Indian Patents. 264694:"A TRANSIT MIXER FOR FLOWABLE MEDIA, IN PARTICULAR CONCRETE "

Title of Invention	"A TRANSIT MIXER FOR FLOWABLE MEDIA, IN PARTICULAR CONCRETE "
Abstract	The invention relates to a transit mixer for free-flowing media, in particular concrete, the mixing drum of said mixer being mounted on supports. According to the invention, the rollers that bear the circular path of the mixing drum are partially sunk in the support housing.

Full Text	Transit mixer for free-flowing media, in particular concrete The invention concerns a transit mixer as set out in the generic part of claim 1. Such transit mixers (DE 44 31 501) have a front and rear pedestal for supporting the mixing drum on the vehicle frame, with the front pedestal bearing the drive for the mixing drum and the rear pedestal provided with two rotatably mounted rollers on which the mixing drum with its circumferential running tread supports itself. The mounting of the rollers is effected by corresponding roller supports with two opposing bearing plates in which the rollers are mounted. The roller supports are bolted by flange-side fillets to the upper side of the pedestal. This design has the disadvantage that the support roller bearings are readily contaminated and, further, a comparatively large gap exists between the running tread and the upper side of the pedestal, as a result of which the risk of an accident increases, because persons working on the transit mixer can very easily reach their hands through the rotating rollers into the given danger area. For this reason, comparatively large covering hoods are necessary for covering the gap to the outside. However, mounting the support roller blocks is very complicated because on one hand exact alignment of the support roller blocks on the pedestal and corresponding alignment of the rollers mounted in the support roller blocks has to be ensured, as a result of which substantial adjustment work is needed. In this regard, it must be remembered that perfect mounting requires the two rollers to be perfectly aligned with regard to the running tread of the mixing drum arranged at an angle on the vehicle frame. The object of the invention is to propose a transit mixer that is safer to operate, less susceptible to contamination and is easier to clean. In a further aspect, essentially no adjustment work for the support roller blocks should be necessary, especially also when rollers are changed. This object is achieved in accordance with the invention by sinking each of the rollers of the pedestal, with the exception of a protruding segment, into the pedestal, with, however, a segment of each roller protruding outward through an opening in the pedestal for the purpose of supporting the mixing drum. As a result, the gap between the running tread or mixing drum and pedestal surface can be essentially minimized, such that access to this area from the outside is very difficult in practice. In this regard, it is expedient that at least the upper section of the pedestal, i.e. in the region of the mounting of the rollers, is designed as a type of box housing, that is, preferably formed from a front and rear support wall, two side cheeks and upper ceiling wall. As a result, the rollers are encapsulated and protected inside the pedestal. Further, the advantage arises that the rollers mounted via bolts in the support walls can be produced in a setting with the pedestal, as a result of which the adjustment work for perfect alignment of the roller surfaces with the running tread of the mixing drum arranged at an angle on the vehicle frame can be facilitated or reduced. In a further embodiment of the invention, the entire pedestal is built in the manner of a housing, as a result of which the pedestal has a compact and rigid structure. In this regard, the pedestal offers hardly any points of attack or points of collection for contamination by collection of concrete and the like and can otherwise be simply cleaned. Especially, however, encapsulation inside the pedestal protects the rollers including the bearings, against contamination, as a result of which the lifetime of the bearings and the rollers is extended. Due to the minimized gap between running tread and pedestal surface, the dimensions of the cover plates for the gap are also reduced. Due to the box-like structure of the support with internal ribs and fillets for rigidity and thus as a hollow construction, the result is a comparatively lightweight, but nonetheless rigid pedestal structure that is mounted to the vehicle frame by laterally set, suitable bearing elements. In a particularly preferred further embodiment of the invention, for which separate protection is sought, the pedestal housing is of a two-limb design. This is effected expediently by providing the lower region of the pedestal with a central, essentially tunnel-like cutout, which is open to the front and to the bottom, preferably also to the rear. The bearing elements for mounting the pedestal to the frame are formed at the lower end of the pedestal limbs. The consequence of this pedestal structure is a certain flexibility that enables torsional stress to be cushioned within the pedestal on travel over uneven ground. If traveling over a pothole leads to twisting of the beam on one side, the flexibility of the two-limb pedestal leads to much lower loads on the bearing mounts of the pedestal, than is the case for a pedestal of high rigidity. Since the cutout is provided in the lower region, more precisely roughly in the lower half of the pedestal, the pedestal has an overlapping hollow structure above the cutout, as a result of which adequate rigidity of the nonetheless more flexibly designed pedestal in the lower bearing area is guaranteed. With regard to the roller bearing, it is expedient that the openings in the box cover for roller reach-through in the axle direction of the rollers are essentially of the roller width and, at right angles to the roller axle direction, smaller than the roller diameter. As a result, the rollers mounted inside the pedestal are perfectly encapsulated and the risk of injury to persons operating the vehicle is reduced. It goes without saying that at any rate the width and the length of the openings are dimensioned such that perfect reach-through of the roller for the purpose of supporting the mixing drum is possible, but that the remaining gap is correspondingly slight. As a consequence of the sunken arrangement of the rollers, only a small roller segment protrudes upwardly over the pedestal, which is sufficient for the mixing drum bearing. Expediently, the roller protrudes above the opening to less than one-third of the roller radius. For the formation of the two-limb pedestal structure, it is expedient if the cutout is essentially U-shaped, more precisely largely edge-free, i.e. curved over the circumference, such that the occurrence of stress peaks is essentially avoided. It is widely known that transit mixers are offered with mixing drums of different volumes. In order that vehicles of different sized mixers may be able to use the one and the same pedestal, the invention also provides for adjusting devices for the front and rear pedestal, for which independent protection is also sought. Mixing drums for different volumes nonetheless have generally the same drum diameter and use the same front and rear drum region, but differ in the length of the cylindrical centre-part of the mixing drum. The outcome of this is that mixing drums with large volumes are formed longer than mixing drums with small volumes. For the vehicle-side bearing, this means that a mixing drum of long design is arranged with its longitudinal axis at a lower angle to the frame than is the case for a shorter mixing drum. Since, in accordance with the invention, the rear pedestal is provided with a longitudinal-adjustment and a tilting device, it is possible when a shorter mixing drum is being used to displace the pedestal forward toward the driver's cabin and especially to tilt it upward about the two front bearing elements, such that the roller surface for supporting the running tread of the mixing drum can, as it were, track the running tread. The front bearing elements may be designed as bearing bolts, bearing pipes, square profiles or the like. Naturally, the pedestal can be locked in the longitudinally-adjusted and tilted position with, in line with the specification of the lengths of the mixing drum caused by the different volumes of the mixing drum, predefined locking positions are specified for when the rear pedestal is longitudinally-displaced or tilted. The front pedestal is analogously fitted with a tilting device, such that here, too, tracking is possible to suit mixing drums of different lengths. A particular advantage is that each of the rollers is supported by a bolt, with at least one roller bearing with an internal and an external ring as well as rolling bodies between them is provided between bolt and roller body, with the internal ring of the roller bearing in the installed state arranged directly coaxially about the bolt. Until now, it was common to provide between the internal ring and bolt a sleeve on which the internal ring was attached. Surprisingly, it has transpired that this sleeve can be dispensed with at no disadvantage. As a result, a further material saving is made. In the design of the invention, the external ring of the roller bearing is pressed into the roller body. The roller bodies, formed as tapered rollers, are located in a cage between the external and the internal ring. Between bolt and internal ring of the roller bearing, provision is made for a clearance fit, such that the bolt can be removed without major application of force. In a further embodiment of the invention, the bolts carrying the rollers are advantageously held detachably, on one hand each in an opening in a first plate forming the front side of the pedestal wall, and, on the other each in a further opposing opening in a plate forming the rear side of the pedestal wall. The plates employed may consist for example of steel, aluminum, carbon fiber materials or plastics. In this embodiment of the invention of a transit mixer, the widely known support roller blocks can be dispensed with. As a result, further material can be saved. The roller bearings, which are arranged coaxially about the bolts, are also arranged inside the pedestal in this embodiment. As a result, the risk of accident is reduced on one hand, and dirt is advantageously prevented from penetrating into the roller bearings on the other. Penetration of dirt into the pedestal can be substantially diminished by providing lateral wiper elements that substantially reduce the gap between rollers and upper pedestal surface. Furthermore, the mounting of the bolts in accordance with the invention is characterized by high strength. It is an advantageous provision that the openings in the interior of the pedestal continue in bearing sleeves coaxial to the bolt or that the openings are formed by the bearing sleeves. Among other things, this safeguards improved bolt introduc- tion. Production accuracy is substantially increased by the design of the invention. By virtue of the fact that the openings in the pedestal can be incorporated after its manufacture, the position of the bolts and thus the position of the bearings to the race and the rollers can be defined exactly. Until now, it was necessary to exactly position the support roller blocks on the pedestal to ensure exact angle positioning. Until now, increased personnel usage was necessary for this. Corresponding advantages also rise during changing of the rollers. It is also conceivable that the bolt is guided at least on one side not through an opening in the plate, but rather is held just in a bearing sleeve in the interior of the pedestal. It is of especial advantage that the bolt is a step bolt, and that the bolt has an external thread at its thin end into which a groove nut is engaged. At its thick end, the bolt has a bolt head with ring contact surface, with the rear of which it contacts the pedestal. Advantageously, a cutout with contact surface in the bearing sleeve or directly in the rear plate is provided. The bolt is advantageously transported with its thin end toward the front from the opening in the rear plate through a central opening in the roller body as far as the opposite opening in the front plate. In this regard, the opening in the rear plate is larger than the opening in the front plate in order that the thick end of the step bolt may be accommodated. A groove nut is now bolted from the outside onto the external thread provided on the thin end of the bolt. The bolt is tensioned with the aid of this groove nut in the bolt pedestal. At the same time, the bolt with its step contact surface is pulled laterally from the rear against the roller bearing, as a result of which the roller bearing is advantageously pre-tensioned. The pre-tension can be arbitrarily adjusted by turning the groove nut. In the rear opening, the bolt is secured against turning, for example by a metal pin. Naturally, the opening sizes etc can also be chosen such that the bolt can be introduced into the pedestal from the front and be attached in this reverse position. To guarantee the simplest possible replacement of the rollers or of the bearings after they are worn, openings, preferably lateral, are provided in the pedestal for replacing the rollers and the roller bearings. Naturally, it is also conceivable for the openings to be provided beneath the rollers in the form of a roller shaft. For changing the rollers, the rollers have to be relieved by supporting the mixing drum. Thereafter, the bolts are loosened by removing the groove nuts and can be taken out from the rear. The roller bodies along with the roller bearing are removed through the side openings and replaced by new roller bodies. To protect the roller bearings against unnecessary contamination, advantageous provision is made for forming the openings such that they are closable. This occurs in the simplest of manners by means of metal or plastic plates to be bolted onto the side of the pedestal. To increase the lifetime of the bearings, a lubricating nipple for lubricating the roller bearings is provided advantageously at the rear or the front of each bolt. It is especially expedient that the pedestal continues upward in each of two carrier arms, especially for mounting the filler hopper and the discharge shell, with the upper edge contour of the plate forming the rear pedestal surface and/or of the plate forming the front pedestal surface being contoured, at least partially, in a U-shape curve or a V-shape. Where mention is made of plates in the description and claims, naturally this includes plates that are also composed of several plates. The measure of continuing the pedestal upward on both sides in each carrier arm has both strength and esthetic advantages. The pedestal construction is stiffened by the U- or V-shape contouring of the plate edges. The carrier arms continue into the pedestal. On account of the special form of the plates, which corresponds to the flow of forces, additional reinforcements between the carrier arms can be dispensed with that were necessary previously to guarantee rigidity of the carrier arms. Especially, forces acting on the carrier arms during cornering are absorbed by the shaping of the pedestal in accordance with the invention. It is furthermore of advantage that the opposing inner surfaces of the plates forming the carrier arms combine essentially into a U-shape or V-shape in the longitudinal central plane of the vehicle and form an upper pedestal surface in which openings are provided for the rollers. The upper pedestal surface avoids penetration of dirt into the pedestal. Shaping of the pedestal surface in accordance with the invention causes the shape of this upper pedestal surface to be adapted to the U- or V-shape of the pedestal side surfaces. The openings inside the upper pedestal surface are necessary in order that the running tread of the mixing drum can be supported by the two rollers of the pedestal. Advantageously, the openings are just large enough to allow the rollers to rotate without any problems. The smaller the opening, the less dirt can get into the inside of the hollow bodies. To further increase the stability of the pedestal carrier arm construction, the plate forming the rear pedestal surface and the plate forming the front pedestal surface are each advantageously connected, especially by welding, by their upper edge to the edges of the plate forming the U-shaped or V-shaped pedestal surface, preferably along the entire length of the edge. Preferred embodiments of the invention are described below with the aid of the drawing. In it, Fig. 1 shows a side view of a transit mixer with a front and rear pedestal, Fig. 2 shows a three-dimensional view of an embodiment of a pedestal with carrier arms, Fig. 3 shows a three-dimensional view of the pedestal in accordance with Fig. 2, seen from another angle, Fig. 4 shows an embodiment of a roller bearing, Fig. 5 shows a three-dimensional view of the pedestal illustrated in Figs. 2 and 3, but without carrier arms and without rollers, Fig. 6 shows a three-dimensional view of a further embodiment of a pedestal in box design, Fig. 7 shows a view of the pedestal illustrated in Fig. 6, seen from another angle, and with the carrier arms attached to it Fig. 8 shows a three-dimensional view of the pedestal in accordance with Figs. 6 and 7 from another angle, Fig. 9 shows a three-dimensional view of a further preferred embodiment of a two-limb pedestal construction, Fig. 10 shows a schematic view of a mixing drum mounted on a front and rear pedestal, and Fig. 11 shows an analogous view in accordance with Fig. 10 of a mixing drum with lower nominal volume, and Fig. 12 shows a further alternative embodiment of a pedestal with 3-point bearing. Fig. 1 shows a concrete mixing vehicle 1 in the form of a truck with a frame 2, which usually is formed from two parallel beams bearing a front and rear pedestal 3 and 4 on which a mixing drum labeled 5 for concrete or similar viscous substances is accommodated and mounted. In the region of the front pedestal 3 is arranged the drive for the mixing drum 5, but this is only illustrated here schematically. The mixing drum 5 is mounted rotatably via a running tread 6 formed on the rear part of the drum on the pedestal. For this purpose, pedestal 4, as can be seen from Fig. 2, has two rollers 7, which are mounted rotatably in pedestal 4. In the embodiment of Figs. 2 and 3, the upper section of the pedestal 4 is formed from a box-shaped housing, which is essentially formed from a front pedestal wall 8 and a rear pedestal wall 9 visible in Fig. 3, which are bridged by a ceiling wall 10. This has an arc shape adjusted to the diameter or the running tread 6 of the mixing drum 5 to be accommodated. On both sides of the upper region of the pedestal are provided two carrier arms 11 which, in the embodiment shown, are equally formed as hollow box profiles and are attached to the box structure of the upper pedestal section. These carrier arms 11 are suitably connected to the pedestal arch, by welding and/or bolted connections, for which purpose the upper front and rear regions of the pedestal wall of the pedestal are provided with suitable interfaces or connecting points 12. Access covers 14 are provided at the side cheeks of the pedestal or, as shown in Fig. 2, the side cheeks 13 of the carrier arms 11, said access covers attached by being slipped on or by bolted connections and providing access from the outside into the inside of the pedestal or to the rollers 7 accommodated therein. The carrier arms 11 encompass the mixing drum 5 on both sides from the side and, as evident from Fig. 1, accommodate the hopper filler 15 for the concrete feed and the discharge hopper 16. Further, a delivery slide 17 is provided. The upper box-shaped part of the pedestal 4 is supported by two inclined supporting struts 18 and rear spars, which are connected to a pedestal frame 19, by means of which the pedestal is arranged on the beams or the frame 2. The pedestal frame 19 is constructed from two longitudinal spars 20 and two cross-spars 21. In the embodiment shown, the supporting struts and the spars are formed by square profiles. As is best seen from Fig. 2, the rollers 7 for mounting the mixing drum are sunk inside the pedestal 4 and protrude from openings 22 in the ceiling wall 10 just far enough as is needed for mounting purposes for supporting the mixing drum. As is especially evident from Figs. 4 and 5, the rollers 7 are mounted on bolts 23, which are designed as step bolts. Each bolt is accommodated in opposing bearing openings 24 and 25 in the front and rear pedestal wall 8 and 9. These openings 24 and 25 continue inside the pedestal box as bearing sleeves 26 and 27, as is best seen in Fig. 5. Across its circumference at the external end, the rear bearing sleeve 27 has a cutout 28 with an annular contact surface. The bolt head 29 of the step bolt 23 is accommodated in this cutout 28 with a lower annular contact surface (Fig. 4). An external thread 30 is provided at the circumference of the thin end of each bearing bolt 23. The bearing bolt 23 is tensioned by means of a groove nut 31 between the rear pedestal wall 4 and the front pedestal wall 3. The thick end of the bearing bolt 23 is secured in the usual way against turning. Between bearing bolt 23 and the rolling body 32 is provided a roller bearing 33 formed as a tapered roller bearing. The outer ring 33 of the roller bearing 33 is pressed into the roller body 32. The roller bodies 35 formed as cone stumps are arranged in a cage not illustrated. The rolling bodies 35 are supported on an inner ring 36. In this embodiment, the roller bearing is formed as a two-row bearing with two inner and two outer rings. In opposition to the known prior art, no sleeve is located between the inner ring 36 and the bearing bolt 23. The inner ring 36 of the roller bearing 35 is arranged coaxially directly about the bearing bolts 23. Between bearing bolt 23 and internal ring 36, provision is made for a clearance fit, such that the bolt 23 can be removed simply. As is best seen from Fig. 2, the upper end face 10 of the pedestal is curved or arched to suit the mixing drum, just like the upper edges 37 and 38 of the front pedestal cheek and the rear pedestal cheek 8 and 9. As a result, only a small gap remains between the mixing drum and pedestal. Additionally, the transition between pedestal 4 and carrier arms 11 is stiffened, a fact which is especially necessitated by the formation of the carrier arms and the pedestal in this region as a hollow profile part. As a result, additional struts between the carrier arms 11 or between the carrier arms 11 and the pedestal 4 can be dispensed with. Consequently, the structure of the pedestal is leaner overall and hardly any dirt-collection points are formed. Further, compact encompassing of the mixing drum occurs, especially caused by the sunken arrangement, very clearly evident from Fig. 2, of the rollers 7 inside the pedestal, such that only narrow trim plates 39 are needed for closing the remaining smaller gap between the circumference of the mixing drum and the upper end face 10 of the pedestal. For the sake of completeness only, it is noted that a bearing console 40 for the single-arm mounting of the swivel arm with chute or delivery slide 17 is provided at the rear pedestal cheek 4. From Fig. 4, finally, wiper elements 41 are visible that reduce the gap between the rollers 7 and the edges of the two openings 22 in the end face 10. Contamination of the bearings is substantially reduced by the wiper elements 41. The wiper elements 41 are formed as angled elements and bolted by their base to the upper pedestal surface. Instead of such wiper elements 41, brushes or rubber wipers and the like may be used. In Figs. 6 to 8 is shown an alternative design for a rear pedestal 4, with the same labels being used for the same parts. By way of difference from the embodiment of Figs. 2, 3 and 5, the pedestal structure shown here has an overall box-like structure. The upper section, accommodating the two carrier arms, with arch-like end face 10 and the upper, front and rear wall section 43 and 44 is built up like the upper section of the pedestal 4 of Figs. 2, 3 and 5. Analogously in this regard, the rollers 7 in the upper pedestal section are sunk inside the box-like or housing-like pedestal 4, said rollers protruding only slightly from the two openings 22 in order that the mixing drum mounted on pedestal 4 may be rotatably accommodated with a small intermediate gap. Insofar, reference in this regard can be made to the embodiment described previously. Here, too, the carrier arms 11 are welded or similarly connected via the connecting point 12 to the upper supper section. As is especially evident from Fig. 6, the lager sleeves 26 and 27 for accommodating the rollers in accordance with Fig. 3 are accommodated in two pedestal cheeks 44 and 45, whose upper edges are shaped analogously to the curve shape of the ceiling wall 10. In connection to these two pedestal cheeks 44 and 45, the pedestal 4 continues downward through a front pedestal wall 46 and a rear pedestal wall, also intact, which is not visible in the drawing. These two pedestal walls are connected laterally to a box housing by corresponding side walls 47. The box housing is correspondingly stiffened by internal ribs or fillets. On each side of the lower end of the pedestal 4 are two protruding axle-journallike bearing parts by means of which the pedestal structure is mounted to the frame. Alternatively, pipes or bolts reaching through the pedestal structure may be provided for this. These may be axle-journal-like lugs, bolts, bearing flanges, bearing fillets and the like. In accordance with the invention, the result is a compact, comparatively rigid, outwardly intact pedestal structure through which especially the mounted rollers 7 are accommodated protectively via the upswept pedestal cheeks. Since the pedestal forms a unit, the bearings for the rollers can be mechanically processed in a unit with the pedestal, as a result of which the adjustment work is greatly simplified. In this regard, allowance must be accorded for the fact that the bearing bolts for the rollers must be aligned exactly in order that perfect, rotary accommodation of the voluminous mixing drum may be guaranteed. On account of the overall smooth outer surfaces, a fact which is especially important for the concrete mixer vehicles described herein, the collection of dirt by concrete or mortar is largely avoided or cleaning facilitated. The bolts 48 are tensioned or bolted in known manner by U-shaped clamps to lateral protrusions of the beams of the frame. The advantage of the overall rigid structure of the embodiment of Figs. 6 to 8 consists in the fact that especially the rolling stability of the vehicle is increased. In a further embodiment of the invention, the box-shaped pedestal structure of Fig. 9 can in turn be formed more flexibly by formation of a central cutout 50 in the front and rear side wall, as a result of which the pedestal structure in the lower region is, as it were, formed in a U-shape with two pedestal limbs 49, to which the axle-journal-like bolts 48 are attached. To be sure, as a result of this the rolling stability is somewhat slightly reduced relative to the embodiment of Figs. 6 to 8 , but corresponding torsional forces can be accommodated in an outstanding manner, said forces arising when a vehicle with a mixing drum loaded with concrete travels over potholes or the like, which can lead to deformation of one of the two beams, as a result of which corresponding twisting can occur in the region of the pedestal structure that can be accommodated on account of the more flexible formation of the pedestal structure in accordance with Fig. 9. As a result, bearing bolts 48 and the mounting of the bolts to the frame are placed under much less stress. It must be remembered that loads of up to 15 t can occur here. When the beam twists as irregularities in the road are traveled over, the twisting can be accommodated inside the pedestal structure. In this regard, it is not necessary for the rear, lower pedestal wall to be formed with such a cutout, rather this can well remain intact, at any rate it must be ensured that, at least in the front region of the pedestal structure, a quasi-two-limb design of the lower region of the box-like pedestal structure is achieved via the cutout. This is best evident from the illustration in Fig. 9. With this embodiment, overloading of the bearing regions of the pedestal structure on the beams is avoided even under high torsional stress. As is known, concrete vehicles come with mixing drums of different size, with generally vehicles with mixing drums having a nominal volume of 6, 7, 8, 9 and 10 m3 being used. Generally, the drum diameter of the mixing drums is the same, but the cylindrical section of the drum is designed with different length. This is best evident from a comparison of Figs. 10 and 11. Fig. 10 shows a mixing drum 5 with a nominal volume of, for example 10 m3, whereas Fig. 11 shows a mixing drum 5 with a nominal volume of 6 m3. The front part 51 and the rear part 52 of the mixing drum in both embodiments of the mixing drum 5 are unchanged, but the central cylindrical section 53 is designed for different lengths. As a result, largely the same parts of the mixing drum can be used for different nominal volumes. In order, in accordance with the invention, that the same pedestals may be used for the front and rear region despite the use of mixing drums of different volumes, the rear pedestal 4 is fitted with an adjustment device that facilitates longitudinal displacement of the rear pedestal in the axial direction of the beam and swiveling of the rear pedestal. In contrast, the front pedestal 3 is fitted with an adjustment device which facilitates swiveling of the front pedestal. Fig. 10 shows in this connection an arrangement of a mixing drum on a concrete vehicle in which the adjustment device of the rear pedestal 4 is in the neutral position, i.e. the pedestal 4 is located in a non-swiveled position in which the axes of the bearing bolts 48 span a plane which is essentially parallel to the beams. For the neutral position, a medium drum size, for example a drum with a nominal volume of 9 m3, is used expediently in order that the tilting angle may not become too great. In the case of the large drums, that is, drums of greater length, the pedestals then have to be tilted backward. In the case of short drums, the pedestals then have to be tilted forward. In this regard, the beams in Figs. 10 and 11 are only indicated schematically by a solid straight line beneath the bearing bolts 48. For the event that a mixing drum in accordance with Fig. 11 is used, which has a smaller nominal volume and thus a not so long cylindrical section 53, the rear pedestal 4 is displaced forward from the neutral position illustrated in Fig. 10 via the adjustment device in consequence of longitudinal guide members, that is, in the direction of the driver's cabin of the concrete vehicle and swiveled slightly upward, relative to its rear region, as is indicated in Fig. 11 by the angle 3. As a result, the roller bearing of the pedestal 4 tracks and is aligned relative to the running tread 6, since, in the short mixing-drum design of Fig. 11, the mixing drum is tilted more extensively than in the case of the long mixing drum of Fig. 10, i.e. the axle of the mixing drum contains a greater angle with the plane of the beams 2 than in Fig. 10. In the embodiment of Fig. 11, the swiveling in this regard occurs in the region of the front bearing bolt 48. The upswept position of the pedestal is then locked in suitable manner, which may be effected for example by welding on a holder or in such a way that flaps or cross-plates attached laterally to the beams have a guide curve for a guide pin provided on the pedestal side, in order to facilitate a swivel movement. Locking then proceeds by corresponding locking pins, with the swiveling motion of the mixing drum adjusting to the different nominal volumes in predefined steps. At the same time, as may be seen from Fig. 11, the front pedestal 3 is swiveled upward about its front bearing bolts through an angle a, such that here as well the pedestal bearing tracks the different nominal volumes of the mixing drums. The embodiment of a pedestal in accordance with Fig. 12 resembles the design of the embodiment of Figs. 6 to 8 in that the pedestal structure has a box-like structure. Admittedly, this pedestal structure is designed to have a 3-point bearing on the frame or the beams. The two rear bearing points for the pedestal structure of Fig. 12, which are labeled 48, are formed in accordance with the embodiment of Figs. 6 to 8, with the bearings 48 formed by a pipe passing through the pedestal structure. However, the mounting of the pedestal structure in the front region is different on account of the design as a 3-point bearing. To this end, in the embodiment shown, the front section of the pedestal structure or the front part is formed by a tapering hood 60 with pyramidal or funnel-like structure, with a bearing bolt 61, shown here as an axle journal, located at the front end. In the ideal case, this contact point is designed as a ball joint or also as an elastic bearing. The pedestal structure is mounted with the two lateral bearings 48 relative to the beams, whereas in contrast the pedestal structure in the front region can be mounted to a traverse or similar that bridges the beam. As is evident from Fig. 12, the bearing position 61 is centrally arranged relative to the pedestal structure or the two bearing points 48. Otherwise, as regards the further shape of the pedestal structure, reference is made to the previous description, especially concerning the upper structure of the pedestal box including the sunken accommodation of the pedestal rollers and the lateral carrier arms of the pedestal structure. The advantage of the 3-point bearing realized in the embodiment of Fig. 12 consists in the fact that, on torsional stress on the two beams of the vehicle frame, one plane is spanned and as a result enforced deformation of the pedestal structure and corresponding overloading of the bearing points is largely avoided. In the case of a 4-point bearing, the pedestal is held in one plane at the vehicle frame by four bearing points. When torsional forces occur on the two beams, the resultant bending which occurs causes at least one of the bearing points to wander out of the spanned plane, such that forces necessarily act on the pedestal and the bearing points. This must be counteracted by a corresponding design of the bearing regions. In the case of the 3-point bearing described, such forced deformation on the pedestal structure can be largely avoided, such that no correspondingly large forces can build up at the bearing points. Patent claims 1. Transit mixer for free-flowing media, especially concrete, with a mixing drum, which has a rear drum discharge and at its outer circumference a running tread, which is rotatably supported by at least two rollers of a pedestal mounted on a vehicle frame, characterized by the fact that the rollers (7) of the pedestal (4) are each, with the exception of a roller segment, sunk in the pedestal (4), with the roller segment protruding through an opening (22) in the pedestal (4) for supporting the mixing drum (5). 2. Transit mixer in accordance with claim 1, characterized by the fact that the roller reach-through opening (22) in the axle direction of the roller (7) is essentially of the roller width and at right angles to the roller axial direction smaller than the roller diameter. 3. Transit mixer in accordance with claims 1 or 2, characterized by the fact that the roller (7) protrudes above the opening (22) to less than one-third of the roller radius. 4. Transit mixer in accordance with any of claims 1 to 3, characterized by the fact that the pedestal (4), at least in its upper section, is formed by a box-like housing with a front and rear support wall (8, 9), with preferably side cheeks and with an upper ceiling wall (10), in which are provided the openings (22) for the reach-through of the rollers (7). 5. Transit mixer in accordance with any of the previous claims, characterized by the fact that the rollers (7) in the front and rear support wall (8, 9) of the pedestal housing are mounted. 6. Transit mixer in accordance with any of the previous claims, characterized by the fact that the entire pedestal (4) is formed as a box housing with a front and rear support wall (45, 46), side cheeks (47) and an upper ceiling wall (10) bearing the roller reach-through openings (22), with a front and a rear bearing part (48) for mounting the pedestal to the vehicle frame provided on both sides of the pedestal at the lower end of the box housing. 7. Transit mixer, especially in accordance with any of the previous claims, characterized by the fact that in the lower pedestal section, preferably at the front, a preferably tunnellike formed cutout (50) is provided, which divides the lower housing section of the pedestal into two lateral pedestal limbs (49), at whose ends the bearing parts (48) for mounting the pedestal to the vehicle frame are arranged. 8. Transit mixer in accordance with claim 7, characterized by the fact that the cutout (50) extends in the longitudinal direction through the pedestal. 9. Transit mixer in accordance with claim 7 or 8, characterized by the fact that the cutout is essentially formed as a U-shape and preferably free of edges around the circumference. 10. Transit mixer, especially in accordance with any of the previous claims, characterized by the fact that the rear pedestal (4) is displaceable in the longitudinal direction of the vehicle frame (2) and is formed such that it tilts away from the vehicle frame. 11. Transit mixer in accordance with claim 10, characterized by the fact that the front pedestal (3) is formed such that it tilts away from the vehicle frame. 12. Transit mixer in accordance with any of the previous claims, characterized by the fact that rollers (7) are each supported by a bolt (23), with at least one roller bearing (33) with an internal and an external ring (36) and with rolling bodies (35) located between them provided between bolt (23) and roller body (32), with the internal ring of the roller bearing (33) in the installed state arranged directly coaxially about the bolt (23). 13. Transit mixer in accordance with any of the previous claims, characterized by the fact that the bolts (23) carrying the rollers (7) are each mounted in an opening (22) in the front and rear pedestal wall. 14. Transit mixer, especially in accordance with any of the previous claims, characterized by the fact that the bolt (23) is a step bolt, and that the bolt (23) has an external thread (30) at its thin end into which a groove nut (31) is engaged. 15. Transit mixer, especially in accordance with any of the previous claims, characterized by the fact that in the pedestal (4), preferably lateral openings are provided for replacing the rolling bodies (32), which preferably are closably formed by means of plates (14) that can be bolted to the pedestal (4). 16 Transit mixer in accordance with any of the previous claims, characterized by the fact that the pedestal (4) continues upward in each of two carrier arms (11), especially for mounting the filler hopper and the discharge shell, with the upper edge contour (37, 38) of the rear pedestal surface (45) and/or the front pedestal surface (44) being adjusted to the mixing drum circumference, essentially contoured in a U-shape or essentially in a V-shape. 17. Transit mixer in accordance with any of the previous claims, characterized by the fact that the rear pedestal wall (39, 45) and the front pedestal wall (8, 44) are each connected, especially welded, by the upper edge (37, 38) to the side edges of the ceiling wall forming the U- or V-shaped upper pedestal surface (10), preferably along the entire length of the edge. 18. Transit mixer, especially in accordance with any of the previous claims, characterized by the fact that the pedestal structure is mounted relative to the vehicle frame by a 3-point bearing. 19. Transit mixer in accordance with claim 18, characterized by the fact that the pedestal structure has two lateral bearing points (48) for mounting to the vehicle frame and an essentially centrally-arranged bearing point (61) for mounting to the vehicle frame, with the centrally- arranged bearing point (61) preferably being arranged in the front region of the pedestal structure. 20. Transit mixer in accordance with claim 18 or 19, characterized by the fact that the pedestal structure is formed with a hood-like front section (60), preferably in pyramidal or hopper shape, at whose front end the bearing point is formed (61). 21. Transit mixer in accordance with any of claims 18 to 20, characterized by the fact that the bearing points (48) for attachment to the beams is formed by a pipe or bolt reaching through the pedestal structure and the front bearing point (61) by an axle-journal-like bearing bolt, a ball joint or elastic bearing, which is mounted to the cross-traverse bridging the beam.

Full Text

Transit mixer for free-flowing media, in particular concrete
The invention concerns a transit mixer as set out in the generic part of claim 1.
Such transit mixers (DE 44 31 501) have a front and rear pedestal for supporting the mixing
drum on the vehicle frame, with the front pedestal bearing the drive for the mixing drum and
the rear pedestal provided with two rotatably mounted rollers on which the mixing drum
with its circumferential running tread supports itself. The mounting of the rollers is effected
by corresponding roller supports with two opposing bearing plates in which the rollers are
mounted. The roller supports are bolted by flange-side fillets to the upper side of the pedestal.
This design has the disadvantage that the support roller bearings are readily contaminated
and, further, a comparatively large gap exists between the running tread and the upper
side of the pedestal, as a result of which the risk of an accident increases, because persons
working on the transit mixer can very easily reach their hands through the rotating rollers
into the given danger area. For this reason, comparatively large covering hoods are necessary
for covering the gap to the outside. However, mounting the support roller blocks is very
complicated because on one hand exact alignment of the support roller blocks on the pedestal
and corresponding alignment of the rollers mounted in the support roller blocks has to be
ensured, as a result of which substantial adjustment work is needed.
In this regard, it must be remembered that perfect mounting requires the two rollers to be
perfectly aligned with regard to the running tread of the mixing drum arranged at an angle
on the vehicle frame.
The object of the invention is to propose a transit mixer that is safer to operate, less susceptible
to contamination and is easier to clean. In a further aspect, essentially no adjustment
work for the support roller blocks should be necessary, especially also when rollers are
changed.
This object is achieved in accordance with the invention by sinking each of the rollers of the
pedestal, with the exception of a protruding segment, into the pedestal, with, however, a
segment of each roller protruding outward through an opening in the pedestal for the purpose
of supporting the mixing drum. As a result, the gap between the running tread or mixing
drum and pedestal surface can be essentially minimized, such that access to this area
from the outside is very difficult in practice. In this regard, it is expedient that at least the
upper section of the pedestal, i.e. in the region of the mounting of the rollers, is designed as
a type of box housing, that is, preferably formed from a front and rear support wall, two side
cheeks and upper ceiling wall. As a result, the rollers are encapsulated and protected inside
the pedestal. Further, the advantage arises that the rollers mounted via bolts in the support
walls can be produced in a setting with the pedestal, as a result of which the adjustment
work for perfect alignment of the roller surfaces with the running tread of the mixing drum
arranged at an angle on the vehicle frame can be facilitated or reduced.
In a further embodiment of the invention, the entire pedestal is built in the manner of a
housing, as a result of which the pedestal has a compact and rigid structure. In this regard,
the pedestal offers hardly any points of attack or points of collection for contamination by
collection of concrete and the like and can otherwise be simply cleaned. Especially, however,
encapsulation inside the pedestal protects the rollers including the bearings, against
contamination, as a result of which the lifetime of the bearings and the rollers is extended.
Due to the minimized gap between running tread and pedestal surface, the dimensions of the
cover plates for the gap are also reduced.
Due to the box-like structure of the support with internal ribs and fillets for rigidity and thus
as a hollow construction, the result is a comparatively lightweight, but nonetheless rigid
pedestal structure that is mounted to the vehicle frame by laterally set, suitable bearing elements.
In a particularly preferred further embodiment of the invention, for which separate protection
is sought, the pedestal housing is of a two-limb design. This is effected expediently by
providing the lower region of the pedestal with a central, essentially tunnel-like cutout,
which is open to the front and to the bottom, preferably also to the rear. The bearing elements
for mounting the pedestal to the frame are formed at the lower end of the pedestal
limbs. The consequence of this pedestal structure is a certain flexibility that enables torsional
stress to be cushioned within the pedestal on travel over uneven ground. If traveling
over a pothole leads to twisting of the beam on one side, the flexibility of the two-limb pedestal
leads to much lower loads on the bearing mounts of the pedestal, than is the case for a
pedestal of high rigidity. Since the cutout is provided in the lower region, more precisely
roughly in the lower half of the pedestal, the pedestal has an overlapping hollow structure
above the cutout, as a result of which adequate rigidity of the nonetheless more flexibly designed
pedestal in the lower bearing area is guaranteed. With regard to the roller bearing, it
is expedient that the openings in the box cover for roller reach-through in the axle direction
of the rollers are essentially of the roller width and, at right angles to the roller axle direction,
smaller than the roller diameter. As a result, the rollers mounted inside the pedestal are
perfectly encapsulated and the risk of injury to persons operating the vehicle is reduced. It
goes without saying that at any rate the width and the length of the openings are dimensioned
such that perfect reach-through of the roller for the purpose of supporting the mixing
drum is possible, but that the remaining gap is correspondingly slight. As a consequence of
the sunken arrangement of the rollers, only a small roller segment protrudes upwardly over
the pedestal, which is sufficient for the mixing drum bearing. Expediently, the roller protrudes
above the opening to less than one-third of the roller radius.
For the formation of the two-limb pedestal structure, it is expedient if the cutout is essentially
U-shaped, more precisely largely edge-free, i.e. curved over the circumference, such
that the occurrence of stress peaks is essentially avoided.
It is widely known that transit mixers are offered with mixing drums of different volumes.
In order that vehicles of different sized mixers may be able to use the one and the same pedestal,
the invention also provides for adjusting devices for the front and rear pedestal, for
which independent protection is also sought. Mixing drums for different volumes nonetheless
have generally the same drum diameter and use the same front and rear drum region,
but differ in the length of the cylindrical centre-part of the mixing drum. The outcome of
this is that mixing drums with large volumes are formed longer than mixing drums with
small volumes. For the vehicle-side bearing, this means that a mixing drum of long design is
arranged with its longitudinal axis at a lower angle to the frame than is the case for a shorter
mixing drum. Since, in accordance with the invention, the rear pedestal is provided with a
longitudinal-adjustment and a tilting device, it is possible when a shorter mixing drum is
being used to displace the pedestal forward toward the driver's cabin and especially to tilt it
upward about the two front bearing elements, such that the roller surface for supporting the
running tread of the mixing drum can, as it were, track the running tread. The front bearing
elements may be designed as bearing bolts, bearing pipes, square profiles or the like. Naturally,
the pedestal can be locked in the longitudinally-adjusted and tilted position with, in
line with the specification of the lengths of the mixing drum caused by the different volumes
of the mixing drum, predefined locking positions are specified for when the rear pedestal is
longitudinally-displaced or tilted. The front pedestal is analogously fitted with a tilting device,
such that here, too, tracking is possible to suit mixing drums of different lengths.
A particular advantage is that each of the rollers is supported by a bolt, with at least one
roller bearing with an internal and an external ring as well as rolling bodies between them is
provided between bolt and roller body, with the internal ring of the roller bearing in the installed
state arranged directly coaxially about the bolt. Until now, it was common to provide
between the internal ring and bolt a sleeve on which the internal ring was attached. Surprisingly,
it has transpired that this sleeve can be dispensed with at no disadvantage. As a result,
a further material saving is made. In the design of the invention, the external ring of the
roller bearing is pressed into the roller body. The roller bodies, formed as tapered rollers, are
located in a cage between the external and the internal ring. Between bolt and internal ring
of the roller bearing, provision is made for a clearance fit, such that the bolt can be removed
without major application of force.
In a further embodiment of the invention, the bolts carrying the rollers are advantageously
held detachably, on one hand each in an opening in a first plate forming the front side of the
pedestal wall, and, on the other each in a further opposing opening in a plate forming the
rear side of the pedestal wall. The plates employed may consist for example of steel, aluminum,
carbon fiber materials or plastics. In this embodiment of the invention of a transit
mixer, the widely known support roller blocks can be dispensed with. As a result, further
material can be saved. The roller bearings, which are arranged coaxially about the bolts, are
also arranged inside the pedestal in this embodiment. As a result, the risk of accident is reduced
on one hand, and dirt is advantageously prevented from penetrating into the roller
bearings on the other. Penetration of dirt into the pedestal can be substantially diminished by
providing lateral wiper elements that substantially reduce the gap between rollers and upper
pedestal surface. Furthermore, the mounting of the bolts in accordance with the invention is
characterized by high strength. It is an advantageous provision that the openings in the interior
of the pedestal continue in bearing sleeves coaxial to the bolt or that the openings are
formed by the bearing sleeves. Among other things, this safeguards improved bolt introduc-
tion.
Production accuracy is substantially increased by the design of the invention. By virtue of
the fact that the openings in the pedestal can be incorporated after its manufacture, the position
of the bolts and thus the position of the bearings to the race and the rollers can be defined
exactly. Until now, it was necessary to exactly position the support roller blocks on the
pedestal to ensure exact angle positioning. Until now, increased personnel usage was necessary
for this. Corresponding advantages also rise during changing of the rollers.
It is also conceivable that the bolt is guided at least on one side not through an opening in
the plate, but rather is held just in a bearing sleeve in the interior of the pedestal.
It is of especial advantage that the bolt is a step bolt, and that the bolt has an external thread
at its thin end into which a groove nut is engaged. At its thick end, the bolt has a bolt head
with ring contact surface, with the rear of which it contacts the pedestal. Advantageously, a
cutout with contact surface in the bearing sleeve or directly in the rear plate is provided. The
bolt is advantageously transported with its thin end toward the front from the opening in the
rear plate through a central opening in the roller body as far as the opposite opening in the
front plate. In this regard, the opening in the rear plate is larger than the opening in the front
plate in order that the thick end of the step bolt may be accommodated. A groove nut is now
bolted from the outside onto the external thread provided on the thin end of the bolt. The
bolt is tensioned with the aid of this groove nut in the bolt pedestal. At the same time, the
bolt with its step contact surface is pulled laterally from the rear against the roller bearing,
as a result of which the roller bearing is advantageously pre-tensioned. The pre-tension can
be arbitrarily adjusted by turning the groove nut. In the rear opening, the bolt is secured
against turning, for example by a metal pin. Naturally, the opening sizes etc can also be chosen
such that the bolt can be introduced into the pedestal from the front and be attached in
this reverse position.
To guarantee the simplest possible replacement of the rollers or of the bearings after they
are worn, openings, preferably lateral, are provided in the pedestal for replacing the rollers
and the roller bearings. Naturally, it is also conceivable for the openings to be provided beneath
the rollers in the form of a roller shaft. For changing the rollers, the rollers have to be
relieved by supporting the mixing drum. Thereafter, the bolts are loosened by removing the
groove nuts and can be taken out from the rear. The roller bodies along with the roller bearing
are removed through the side openings and replaced by new roller bodies.
To protect the roller bearings against unnecessary contamination, advantageous provision is
made for forming the openings such that they are closable. This occurs in the simplest of
manners by means of metal or plastic plates to be bolted onto the side of the pedestal.
To increase the lifetime of the bearings, a lubricating nipple for lubricating the roller bearings
is provided advantageously at the rear or the front of each bolt.
It is especially expedient that the pedestal continues upward in each of two carrier arms,
especially for mounting the filler hopper and the discharge shell, with the upper edge contour
of the plate forming the rear pedestal surface and/or of the plate forming the front pedestal
surface being contoured, at least partially, in a U-shape curve or a V-shape. Where
mention is made of plates in the description and claims, naturally this includes plates that
are also composed of several plates. The measure of continuing the pedestal upward on both
sides in each carrier arm has both strength and esthetic advantages. The pedestal construction
is stiffened by the U- or V-shape contouring of the plate edges. The carrier arms continue
into the pedestal. On account of the special form of the plates, which corresponds to
the flow of forces, additional reinforcements between the carrier arms can be dispensed with
that were necessary previously to guarantee rigidity of the carrier arms. Especially, forces
acting on the carrier arms during cornering are absorbed by the shaping of the pedestal in
accordance with the invention.
It is furthermore of advantage that the opposing inner surfaces of the plates forming the carrier
arms combine essentially into a U-shape or V-shape in the longitudinal central plane of
the vehicle and form an upper pedestal surface in which openings are provided for the rollers.
The upper pedestal surface avoids penetration of dirt into the pedestal. Shaping of the
pedestal surface in accordance with the invention causes the shape of this upper pedestal
surface to be adapted to the U- or V-shape of the pedestal side surfaces. The openings inside
the upper pedestal surface are necessary in order that the running tread of the mixing
drum can be supported by the two rollers of the pedestal. Advantageously, the openings are
just large enough to allow the rollers to rotate without any problems. The smaller the opening,
the less dirt can get into the inside of the hollow bodies.
To further increase the stability of the pedestal carrier arm construction, the plate forming
the rear pedestal surface and the plate forming the front pedestal surface are each advantageously
connected, especially by welding, by their upper edge to the edges of the plate
forming the U-shaped or V-shaped pedestal surface, preferably along the entire length of the
edge.
Preferred embodiments of the invention are described below with the aid of the drawing. In
it,
Fig. 1 shows a side view of a transit mixer with a front and rear pedestal,
Fig. 2 shows a three-dimensional view of an embodiment of a pedestal with carrier arms,
Fig. 3 shows a three-dimensional view of the pedestal in accordance with Fig. 2, seen from
another angle,
Fig. 4 shows an embodiment of a roller bearing,
Fig. 5 shows a three-dimensional view of the pedestal illustrated in Figs. 2 and 3, but without
carrier arms and without rollers,
Fig. 6 shows a three-dimensional view of a further embodiment of a pedestal in box design,
Fig. 7 shows a view of the pedestal illustrated in Fig. 6, seen from another angle, and with
the carrier arms attached to it
Fig. 8 shows a three-dimensional view of the pedestal in accordance with Figs. 6 and 7 from
another angle,
Fig. 9 shows a three-dimensional view of a further preferred embodiment of a two-limb
pedestal construction,
Fig. 10 shows a schematic view of a mixing drum mounted on a front and rear pedestal, and
Fig. 11 shows an analogous view in accordance with Fig. 10 of a mixing drum with lower
nominal volume, and
Fig. 12 shows a further alternative embodiment of a pedestal with 3-point bearing.
Fig. 1 shows a concrete mixing vehicle 1 in the form of a truck with a frame 2, which usually
is formed from two parallel beams bearing a front and rear pedestal 3 and 4 on which a
mixing drum labeled 5 for concrete or similar viscous substances is accommodated and
mounted. In the region of the front pedestal 3 is arranged the drive for the mixing drum 5,
but this is only illustrated here schematically. The mixing drum 5 is mounted rotatably via a
running tread 6 formed on the rear part of the drum on the pedestal. For this purpose, pedestal
4, as can be seen from Fig. 2, has two rollers 7, which are mounted rotatably in pedestal
4.
In the embodiment of Figs. 2 and 3, the upper section of the pedestal 4 is formed from a
box-shaped housing, which is essentially formed from a front pedestal wall 8 and a rear
pedestal wall 9 visible in Fig. 3, which are bridged by a ceiling wall 10. This has an arc
shape adjusted to the diameter or the running tread 6 of the mixing drum 5 to be accommodated.
On both sides of the upper region of the pedestal are provided two carrier arms 11 which, in
the embodiment shown, are equally formed as hollow box profiles and are attached to the
box structure of the upper pedestal section. These carrier arms 11 are suitably connected to
the pedestal arch, by welding and/or bolted connections, for which purpose the upper front
and rear regions of the pedestal wall of the pedestal are provided with suitable interfaces or
connecting points 12. Access covers 14 are provided at the side cheeks of the pedestal or, as
shown in Fig. 2, the side cheeks 13 of the carrier arms 11, said access covers attached by
being slipped on or by bolted connections and providing access from the outside into the
inside of the pedestal or to the rollers 7 accommodated therein. The carrier arms 11 encompass
the mixing drum 5 on both sides from the side and, as evident from Fig. 1, accommodate
the hopper filler 15 for the concrete feed and the discharge hopper 16. Further, a delivery
slide 17 is provided.
The upper box-shaped part of the pedestal 4 is supported by two inclined supporting struts
18 and rear spars, which are connected to a pedestal frame 19, by means of which the pedestal
is arranged on the beams or the frame 2. The pedestal frame 19 is constructed from two
longitudinal spars 20 and two cross-spars 21. In the embodiment shown, the supporting
struts and the spars are formed by square profiles.
As is best seen from Fig. 2, the rollers 7 for mounting the mixing drum are sunk inside the
pedestal 4 and protrude from openings 22 in the ceiling wall 10 just far enough as is needed
for mounting purposes for supporting the mixing drum.
As is especially evident from Figs. 4 and 5, the rollers 7 are mounted on bolts 23, which are
designed as step bolts. Each bolt is accommodated in opposing bearing openings 24 and 25
in the front and rear pedestal wall 8 and 9. These openings 24 and 25 continue inside the
pedestal box as bearing sleeves 26 and 27, as is best seen in Fig. 5.
Across its circumference at the external end, the rear bearing sleeve 27 has a cutout 28 with
an annular contact surface. The bolt head 29 of the step bolt 23 is accommodated in this
cutout 28 with a lower annular contact surface (Fig. 4). An external thread 30 is provided at
the circumference of the thin end of each bearing bolt 23. The bearing bolt 23 is tensioned
by means of a groove nut 31 between the rear pedestal wall 4 and the front pedestal wall 3.
The thick end of the bearing bolt 23 is secured in the usual way against turning.
Between bearing bolt 23 and the rolling body 32 is provided a roller bearing 33 formed as a
tapered roller bearing. The outer ring 33 of the roller bearing 33 is pressed into the roller
body 32. The roller bodies 35 formed as cone stumps are arranged in a cage not illustrated.
The rolling bodies 35 are supported on an inner ring 36.
In this embodiment, the roller bearing is formed as a two-row bearing with two inner and
two outer rings. In opposition to the known prior art, no sleeve is located between the inner
ring 36 and the bearing bolt 23. The inner ring 36 of the roller bearing 35 is arranged coaxially
directly about the bearing bolts 23.
Between bearing bolt 23 and internal ring 36, provision is made for a clearance fit, such that
the bolt 23 can be removed simply.
As is best seen from Fig. 2, the upper end face 10 of the pedestal is curved or arched to suit
the mixing drum, just like the upper edges 37 and 38 of the front pedestal cheek and the rear
pedestal cheek 8 and 9. As a result, only a small gap remains between the mixing drum and
pedestal. Additionally, the transition between pedestal 4 and carrier arms 11 is stiffened, a
fact which is especially necessitated by the formation of the carrier arms and the pedestal in
this region as a hollow profile part. As a result, additional struts between the carrier arms 11
or between the carrier arms 11 and the pedestal 4 can be dispensed with. Consequently, the
structure of the pedestal is leaner overall and hardly any dirt-collection points are formed.
Further, compact encompassing of the mixing drum occurs, especially caused by the sunken
arrangement, very clearly evident from Fig. 2, of the rollers 7 inside the pedestal, such that
only narrow trim plates 39 are needed for closing the remaining smaller gap between the
circumference of the mixing drum and the upper end face 10 of the pedestal.
For the sake of completeness only, it is noted that a bearing console 40 for the single-arm
mounting of the swivel arm with chute or delivery slide 17 is provided at the rear pedestal
cheek 4.
From Fig. 4, finally, wiper elements 41 are visible that reduce the gap between the rollers 7
and the edges of the two openings 22 in the end face 10.
Contamination of the bearings is substantially reduced by the wiper elements 41.
The wiper elements 41 are formed as angled elements and bolted by their base to the upper
pedestal surface. Instead of such wiper elements 41, brushes or rubber wipers and the like
may be used.
In Figs. 6 to 8 is shown an alternative design for a rear pedestal 4, with the same labels being
used for the same parts. By way of difference from the embodiment of Figs. 2, 3 and 5,
the pedestal structure shown here has an overall box-like structure. The upper section, accommodating
the two carrier arms, with arch-like end face 10 and the upper, front and rear
wall section 43 and 44 is built up like the upper section of the pedestal 4 of Figs. 2, 3 and 5.
Analogously in this regard, the rollers 7 in the upper pedestal section are sunk inside the
box-like or housing-like pedestal 4, said rollers protruding only slightly from the two openings
22 in order that the mixing drum mounted on pedestal 4 may be rotatably accommodated
with a small intermediate gap.
Insofar, reference in this regard can be made to the embodiment described previously.
Here, too, the carrier arms 11 are welded or similarly connected via the connecting point 12
to the upper supper section. As is especially evident from Fig. 6, the lager sleeves 26 and 27
for accommodating the rollers in accordance with Fig. 3 are accommodated in two pedestal
cheeks 44 and 45, whose upper edges are shaped analogously to the curve shape of the ceiling
wall 10. In connection to these two pedestal cheeks 44 and 45, the pedestal 4 continues
downward through a front pedestal wall 46 and a rear pedestal wall, also intact, which is not
visible in the drawing. These two pedestal walls are connected laterally to a box housing by
corresponding side walls 47. The box housing is correspondingly stiffened by internal ribs
or fillets. On each side of the lower end of the pedestal 4 are two protruding axle-journallike
bearing parts by means of which the pedestal structure is mounted to the frame. Alternatively,
pipes or bolts reaching through the pedestal structure may be provided for this.
These may be axle-journal-like lugs, bolts, bearing flanges, bearing fillets and the like. In
accordance with the invention, the result is a compact, comparatively rigid, outwardly intact
pedestal structure through which especially the mounted rollers 7 are accommodated protectively
via the upswept pedestal cheeks. Since the pedestal forms a unit, the bearings for the
rollers can be mechanically processed in a unit with the pedestal, as a result of which the
adjustment work is greatly simplified. In this regard, allowance must be accorded for the
fact that the bearing bolts for the rollers must be aligned exactly in order that perfect, rotary
accommodation of the voluminous mixing drum may be guaranteed. On account of the
overall smooth outer surfaces, a fact which is especially important for the concrete mixer
vehicles described herein, the collection of dirt by concrete or mortar is largely avoided or
cleaning facilitated.
The bolts 48 are tensioned or bolted in known manner by U-shaped clamps to lateral protrusions
of the beams of the frame. The advantage of the overall rigid structure of the embodiment
of Figs. 6 to 8 consists in the fact that especially the rolling stability of the vehicle is
increased.
In a further embodiment of the invention, the box-shaped pedestal structure of Fig. 9 can in
turn be formed more flexibly by formation of a central cutout 50 in the front and rear side
wall, as a result of which the pedestal structure in the lower region is, as it were, formed in a
U-shape with two pedestal limbs 49, to which the axle-journal-like bolts 48 are attached. To
be sure, as a result of this the rolling stability is somewhat slightly reduced relative to the
embodiment of Figs. 6 to 8 , but corresponding torsional forces can be accommodated in an
outstanding manner, said forces arising when a vehicle with a mixing drum loaded with
concrete travels over potholes or the like, which can lead to deformation of one of the two
beams, as a result of which corresponding twisting can occur in the region of the pedestal
structure that can be accommodated on account of the more flexible formation of the pedestal
structure in accordance with Fig. 9. As a result, bearing bolts 48 and the mounting of the
bolts to the frame are placed under much less stress. It must be remembered that loads of up
to 15 t can occur here. When the beam twists as irregularities in the road are traveled over,
the twisting can be accommodated inside the pedestal structure. In this regard, it is not necessary
for the rear, lower pedestal wall to be formed with such a cutout, rather this can well
remain intact, at any rate it must be ensured that, at least in the front region of the pedestal
structure, a quasi-two-limb design of the lower region of the box-like pedestal structure is
achieved via the cutout. This is best evident from the illustration in Fig. 9. With this embodiment,
overloading of the bearing regions of the pedestal structure on the beams is
avoided even under high torsional stress.
As is known, concrete vehicles come with mixing drums of different size, with generally
vehicles with mixing drums having a nominal volume of 6, 7, 8, 9 and 10 m3 being used.
Generally, the drum diameter of the mixing drums is the same, but the cylindrical section of
the drum is designed with different length. This is best evident from a comparison of Figs.
10 and 11. Fig. 10 shows a mixing drum 5 with a nominal volume of, for example 10 m3,
whereas Fig. 11 shows a mixing drum 5 with a nominal volume of 6 m3. The front part 51
and the rear part 52 of the mixing drum in both embodiments of the mixing drum 5 are unchanged,
but the central cylindrical section 53 is designed for different lengths. As a result,
largely the same parts of the mixing drum can be used for different nominal volumes. In
order, in accordance with the invention, that the same pedestals may be used for the front
and rear region despite the use of mixing drums of different volumes, the rear pedestal 4 is
fitted with an adjustment device that facilitates longitudinal displacement of the rear pedestal
in the axial direction of the beam and swiveling of the rear pedestal. In contrast, the front
pedestal 3 is fitted with an adjustment device which facilitates swiveling of the front pedestal.
Fig. 10 shows in this connection an arrangement of a mixing drum on a concrete vehicle in
which the adjustment device of the rear pedestal 4 is in the neutral position, i.e. the pedestal
4 is located in a non-swiveled position in which the axes of the bearing bolts 48 span a plane
which is essentially parallel to the beams.
For the neutral position, a medium drum size, for example a drum with a nominal volume of
9 m3, is used expediently in order that the tilting angle may not become too great. In the
case of the large drums, that is, drums of greater length, the pedestals then have to be tilted
backward. In the case of short drums, the pedestals then have to be tilted forward. In this
regard, the beams in Figs. 10 and 11 are only indicated schematically by a solid straight line
beneath the bearing bolts 48. For the event that a mixing drum in accordance with Fig. 11 is
used, which has a smaller nominal volume and thus a not so long cylindrical section 53, the
rear pedestal 4 is displaced forward from the neutral position illustrated in Fig. 10 via the
adjustment device in consequence of longitudinal guide members, that is, in the direction of
the driver's cabin of the concrete vehicle and swiveled slightly upward, relative to its rear
region, as is indicated in Fig. 11 by the angle 3. As a result, the roller bearing of the pedestal
4 tracks and is aligned relative to the running tread 6, since, in the short mixing-drum design
of Fig. 11, the mixing drum is tilted more extensively than in the case of the long mixing
drum of Fig. 10, i.e. the axle of the mixing drum contains a greater angle with the plane of
the beams 2 than in Fig. 10. In the embodiment of Fig. 11, the swiveling in this regard occurs
in the region of the front bearing bolt 48. The upswept position of the pedestal is then
locked in suitable manner, which may be effected for example by welding on a holder or in
such a way that flaps or cross-plates attached laterally to the beams have a guide curve for a
guide pin provided on the pedestal side, in order to facilitate a swivel movement. Locking
then proceeds by corresponding locking pins, with the swiveling motion of the mixing drum
adjusting to the different nominal volumes in predefined steps. At the same time, as may be
seen from Fig. 11, the front pedestal 3 is swiveled upward about its front bearing bolts
through an angle a, such that here as well the pedestal bearing tracks the different nominal
volumes of the mixing drums.
The embodiment of a pedestal in accordance with Fig. 12 resembles the design of the embodiment
of Figs. 6 to 8 in that the pedestal structure has a box-like structure.
Admittedly, this pedestal structure is designed to have a 3-point bearing on the frame or the
beams. The two rear bearing points for the pedestal structure of Fig. 12, which are labeled
48, are formed in accordance with the embodiment of Figs. 6 to 8, with the bearings 48
formed by a pipe passing through the pedestal structure. However, the mounting of the pedestal
structure in the front region is different on account of the design as a 3-point bearing.
To this end, in the embodiment shown, the front section of the pedestal structure or the front
part is formed by a tapering hood 60 with pyramidal or funnel-like structure, with a bearing
bolt 61, shown here as an axle journal, located at the front end. In the ideal case, this contact
point is designed as a ball joint or also as an elastic bearing. The pedestal structure is
mounted with the two lateral bearings 48 relative to the beams, whereas in contrast the pedestal
structure in the front region can be mounted to a traverse or similar that bridges the
beam. As is evident from Fig. 12, the bearing position 61 is centrally arranged relative to the
pedestal structure or the two bearing points 48. Otherwise, as regards the further shape of
the pedestal structure, reference is made to the previous description, especially concerning
the upper structure of the pedestal box including the sunken accommodation of the pedestal
rollers and the lateral carrier arms of the pedestal structure.
The advantage of the 3-point bearing realized in the embodiment of Fig. 12 consists in the
fact that, on torsional stress on the two beams of the vehicle frame, one plane is spanned and
as a result enforced deformation of the pedestal structure and corresponding overloading of
the bearing points is largely avoided. In the case of a 4-point bearing, the pedestal is held in
one plane at the vehicle frame by four bearing points. When torsional forces occur on the
two beams, the resultant bending which occurs causes at least one of the bearing points to
wander out of the spanned plane, such that forces necessarily act on the pedestal and the
bearing points. This must be counteracted by a corresponding design of the bearing regions.
In the case of the 3-point bearing described, such forced deformation on the pedestal structure
can be largely avoided, such that no correspondingly large forces can build up at the
bearing points.

Patent claims
1. Transit mixer for free-flowing media, especially concrete, with a mixing drum, which has
a rear drum discharge and at its outer circumference a running tread, which is rotatably supported
by at least two rollers of a pedestal mounted on a vehicle frame, characterized by
the fact that the rollers (7) of the pedestal (4) are each, with the exception of a roller segment,
sunk in the pedestal (4), with the roller segment protruding through an opening (22) in
the pedestal (4) for supporting the mixing drum (5).
2. Transit mixer in accordance with claim 1, characterized by the fact that the roller
reach-through opening (22) in the axle direction of the roller (7) is essentially of the roller
width and at right angles to the roller axial direction smaller than the roller diameter.
3. Transit mixer in accordance with claims 1 or 2, characterized by the fact that the roller
(7) protrudes above the opening (22) to less than one-third of the roller radius.
4. Transit mixer in accordance with any of claims 1 to 3, characterized by the fact that the
pedestal (4), at least in its upper section, is formed by a box-like housing with a front and
rear support wall (8, 9), with preferably side cheeks and with an upper ceiling wall (10), in
which are provided the openings (22) for the reach-through of the rollers (7).
5. Transit mixer in accordance with any of the previous claims, characterized by the fact
that the rollers (7) in the front and rear support wall (8, 9) of the pedestal housing are
mounted.
6. Transit mixer in accordance with any of the previous claims, characterized by the fact
that the entire pedestal (4) is formed as a box housing with a front and rear support wall
(45, 46), side cheeks (47) and an upper ceiling wall (10) bearing the roller reach-through
openings (22), with a front and a rear bearing part (48) for mounting the pedestal to the vehicle
frame provided on both sides of the pedestal at the lower end of the box housing.
7. Transit mixer, especially in accordance with any of the previous claims, characterized
by the fact that in the lower pedestal section, preferably at the front, a preferably tunnellike
formed cutout (50) is provided, which divides the lower housing section of the pedestal
into two lateral pedestal limbs (49), at whose ends the bearing parts (48) for mounting the
pedestal to the vehicle frame are arranged.
8. Transit mixer in accordance with claim 7, characterized by the fact that the cutout (50)
extends in the longitudinal direction through the pedestal.
9. Transit mixer in accordance with claim 7 or 8, characterized by the fact that the cutout
is essentially formed as a U-shape and preferably free of edges around the circumference.
10. Transit mixer, especially in accordance with any of the previous claims, characterized
by the fact that the rear pedestal (4) is displaceable in the longitudinal direction of the vehicle
frame (2) and is formed such that it tilts away from the vehicle frame.
11. Transit mixer in accordance with claim 10, characterized by the fact that the front
pedestal (3) is formed such that it tilts away from the vehicle frame.
12. Transit mixer in accordance with any of the previous claims, characterized by the fact
that rollers (7) are each supported by a bolt (23), with at least one roller bearing (33) with
an internal and an external ring (36) and with rolling bodies (35) located between them provided
between bolt (23) and roller body (32), with the internal ring of the roller bearing (33)
in the installed state arranged directly coaxially about the bolt (23).
13. Transit mixer in accordance with any of the previous claims, characterized by the fact
that the bolts (23) carrying the rollers (7) are each mounted in an opening (22) in the front
and rear pedestal wall.
14. Transit mixer, especially in accordance with any of the previous claims, characterized
by the fact that the bolt (23) is a step bolt, and that the bolt (23) has an external thread (30)
at its thin end into which a groove nut (31) is engaged.
15. Transit mixer, especially in accordance with any of the previous claims, characterized
by the fact that in the pedestal (4), preferably lateral openings are provided for replacing
the rolling bodies (32), which preferably are closably formed by means of plates (14) that
can be bolted to the pedestal (4).
16 Transit mixer in accordance with any of the previous claims, characterized by the fact
that the pedestal (4) continues upward in each of two carrier arms (11), especially for
mounting the filler hopper and the discharge shell, with the upper edge contour (37, 38) of
the rear pedestal surface (45) and/or the front pedestal surface (44) being adjusted to the
mixing drum circumference, essentially contoured in a U-shape or essentially in a V-shape.
17. Transit mixer in accordance with any of the previous claims, characterized by the fact
that the rear pedestal wall (39, 45) and the front pedestal wall (8, 44) are each connected,
especially welded, by the upper edge (37, 38) to the side edges of the ceiling wall forming
the U- or V-shaped upper pedestal surface (10), preferably along the entire length of the
edge.
18. Transit mixer, especially in accordance with any of the previous claims, characterized
by the fact that the pedestal structure is mounted relative to the vehicle frame by a 3-point
bearing.
19. Transit mixer in accordance with claim 18, characterized by the fact that the pedestal
structure has two lateral bearing points (48) for mounting to the vehicle frame and an essentially
centrally-arranged bearing point (61) for mounting to the vehicle frame, with the centrally-
arranged bearing point (61) preferably being arranged in the front region of the pedestal
structure.
20. Transit mixer in accordance with claim 18 or 19, characterized by the fact that the
pedestal structure is formed with a hood-like front section (60), preferably in pyramidal or
hopper shape, at whose front end the bearing point is formed (61).
21. Transit mixer in accordance with any of claims 18 to 20, characterized by the fact that
the bearing points (48) for attachment to the beams is formed by a pipe or bolt reaching
through the pedestal structure and the front bearing point (61) by an axle-journal-like bearing
bolt, a ball joint or elastic bearing, which is mounted to the cross-traverse bridging the
beam.

Documents:

4738-DELNP-2006 (PETITION UNDER RULE 137).pdf

4738-delnp-2006-Abstract-(23-11-2012).pdf

4738-DELNP-2006-Abstract-261114.pdf

4738-delnp-2006-abstract.pdf

4738-DELNP-2006-Amended Pages Of Specification-261114.pdf

4738-delnp-2006-Claims-(23-11-2012).pdf

4738-DELNP-2006-Claims-261114.pdf

4738-delnp-2006-claims.pdf

4738-delnp-2006-Correspondance Others-(22-04-2013).pdf

4738-delnp-2006-Correspondence Others-(23-11-2012).pdf

4738-delnp-2006-correspondence-others-1.pdf

4738-delnp-2006-correspondence-others.pdf

4738-delnp-2006-description (complete).pdf

4738-delnp-2006-Drawings-(23-11-2012).pdf

4738-delnp-2006-drawings.pdf

4738-DELNP-2006-Form 1-261114.pdf

4738-DELNP-2006-Form 2(Title Page)-261114.pdf

4738-delnp-2006-form-1.pdf

4738-delnp-2006-form-18.pdf

4738-delnp-2006-Form-2-(23-11-2012).pdf

4738-delnp-2006-form-2.pdf

4738-delnp-2006-Form-3-(23-11-2012).pdf

4738-delnp-2006-form-3.pdf

4738-delnp-2006-form-5.pdf

4738-delnp-2006-GPA-(23-11-2012).pdf

4738-delnp-2006-gpa.pdf

4738-DELNP-2006-OTHERS-261114.pdf

4738-delnp-2006-pct-210.pdf

4738-delnp-2006-pct-237.pdf

4738-delnp-2006-pct-304.pdf

4738-delnp-2006-pct-338.pdf

4738-delnp-2006-pct-373.pdf

4738-delnp-2006-Petition-137-(23-11-2012).pdf

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Patent Number

264694

Indian Patent Application Number

4738/DELNP/2006

PG Journal Number

04/2015

Publication Date

23-Jan-2015

Grant Date

15-Jan-2015

Date of Filing

18-Aug-2006

Name of Patentee

STETTER GMBH

Applicant Address

DR. KARL-LENZ-STRASSE 70, 87700 MEMMINGEN, GERMANY

Inventors:

#	Inventor's Name	Inventor's Address
1	SIEGFRIED BUCHTA	AN DEN EICHEN 6, 87758 KRONBURG, GERMANY
2	JOCHEN GORLICH	ZUR SCHONEN AUSSICHT 24, 58579 SCHALKSMUHLE, GERMANY
3	ZORAN ANIC	UNTERER OTTILIENWEG 1, 87000 MEMMINGEN, GERMANY

PCT International Classification Number

B28C

PCT International Application Number

PCT/EP2005/000539

PCT International Filing date

2005-01-20

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10 2004 003 373.0	2004-01-22	Germany