Title of Invention	A SENSOR AND AN APPARATUS FITTED THEREWITH
Abstract	Abstract of the Disclosure It is a question of an instrumentality (1) and a sensor (2) adapted to be secured in an anchoring groove (17) in the instrumentality undercut in a stepped manner, such sensor (2) having an elongated sensor housing (36) with a recess (44), in which a clamping unit (37), able to be turned about an axis (55) of rotation, is placed, such clamping unit having a clamping part (56) with diametrally opposite clamping fins and an actuating part (57) serving for rotational operation of the clamping part (56). The clamping part (56) is able to be moved by rotation of the actuating part (57) between a clamping position with the clamping fins (63) extended in relation to the two side faces (43) of the sensor housing (36) and a release position further retracted in relation to same. The clamping part (56) and the actuating part (57) are two separate components able to be turned about the axis of rotation (55) in relation to each other, which are in screw-threaded engagement, the actuating part (5 7) being rotatably supported on the sensor housing (36) without screw-threaded engagement and is simultaneously supported in a downward direction without extending past a support face (54) formed by the bottom side of the sensor housing (36) serving for support on the floor (27) of the anchoring groove (17). Figure 1.

Title of Invention

A SENSOR AND AN APPARATUS FITTED THEREWITH

Abstract

Abstract of the Disclosure It is a question of an instrumentality (1) and a sensor (2) adapted to be secured in an anchoring groove (17) in the instrumentality undercut in a stepped manner, such sensor (2) having an elongated sensor housing (36) with a recess (44), in which a clamping unit (37), able to be turned about an axis (55) of rotation, is placed, such clamping unit having a clamping part (56) with diametrally opposite clamping fins and an actuating part (57) serving for rotational operation of the clamping part (56). The clamping part (56) is able to be moved by rotation of the actuating part (57) between a clamping position with the clamping fins (63) extended in relation to the two side faces (43) of the sensor housing (36) and a release position further retracted in relation to same. The clamping part (56) and the actuating part (57) are two separate components able to be turned about the axis of rotation (55) in relation to each other, which are in screw-threaded engagement, the actuating part (5 7) being rotatably supported on the sensor housing (36) without screw-threaded engagement and is simultaneously supported in a downward direction without extending past a support face (54) formed by the bottom side of the sensor housing (36) serving for support on the floor (27) of the anchoring groove (17). Figure 1.

Full Text	--A SENSOR AND AN APPARATUS FITTED THEREWITH-- The invention relates to a sensor adapted to be secured in an anchoring groove which is undercut in a stepped manner, and in particular a position sensor, comprising an elongated sensor housing having at a distance from its two terminal faces at least one recess open towards its top side and to the two side faces, and in which a clamping unit is arranged able to be turned about an axis of rotation extending in the same direction as the height axis of the sensor housing, such clamping unit having a clamping part with two diametrally opposite clamping fins and an actuating part serving for rotary actuation of the clamping part, the clamping part being able to be moved by rotation of the actuating part between a clamping position with the clamping fins extended in relation to the two side faces of the sensor housing and a release position further retracted in relation to same. The invention is furthermore directed to an instrumentality comprising at least one apparatus, as for example a fluid power linear drive, fitted with such a sensor. One prior art device in this category is disclosed in the German patent publication DE 20211518 Ul. The sensor described in this case comprises a sensor housing with an essentially central recess, in which an integral clamping unit defining a clamping part and an actuating part is held in a rotatable manner. The clamping part has diametrally opposite clamping fins, on which radially outwardly facing clamping faces with an eccentric configuration are formed. The mounting of the sensor in an anchoring groove takes place turning with a tool so that the clamping fins, so far located in a retracted release position, are extended to the side and assuming the clamping position are braced against the oppositely placed groove flanks. The sensor may admittedly be relatively simply secured. However in certain circumstances there remains a certain clearance for movement between the sensor housing containing the sensor means and the device component having the anchoring groove. This may in unfavorable circumstances, as for example vibrations, lead to imperfect functioning. The German patent publication DE 9414869 Ul describes an arrangement, in which a sensor is able to be secured inter alia by means of a terminally arranged two-part clamping unit in an anchoring groove. The clamping unit possesses a rotatably movable clamping part and an actuating part in screw-threaded engagement with it. By rotation of the actuating part the clamping part may be shifted into a clamping position fitting underneath the groove's neck, the actuating part being simultaneously clamped against the groove's floor. Since the sensor housing is then not reliably held in position by these means by themselves, an additional detent connection means is arranged at the opposite terminal portion of the sensor housing, something which however renders manufacture more complex. A similar arrangement but without any detent connection means and without a pivotal clamping part is described in the Patent Abstract of Japan relating to the Japanese patent publication JP 2001280310 A. In accordance with the German patent publication DE 196 48 679 C2 a sensor with an anchoring groove is secured by a non-rotatable clamping part, consisting of two lugs able to be spread apart by means of a screw operated spreading body. An attachment device described in the German patent publication DE 102 31 481 B3 for a sensor comprises a clamping part operated by turning to clamp onto longitudinal ribs of an attachment groove. In the case of the German patent publication DE 203 12 472 Ul an attachment device for a sensor comprises two resiliently elastic clamping yokes for clamping in an attachment groove. The German patent publication DE 199 3 0 02 0 Al discloses a linear drive in which a tubular body is closed by a closure plug anchored by a security pin. The present invention has the aim of suggesting measures for locking a sensor ensuring a simple and secure attachment in an anchoring groove which is undercut in a stepped manner. In order to achieve such an aim in the case of a sensor of the type initially mentioned there a provision such that the clamping part and the actuating part are two separate components able to be turned about the axis of rotation in relation to each other, which are in screw-threaded engagement, the actuating part being rotatably supported on the sensor housing without screw-threaded engagement and being simultaneously supported in a downward direction without extending past a support face formed by the bottom side of the sensor housing for support on the floor of the anchoring groove. The object is furthermore to be achieved by an instrumentality which comprises an apparatus with two apparatus components able to be shifted in relation to one another, the one apparatus component having at least one anchoring groove which is undercut in a stepped manner in which at least one sensor in accordance with the invention is releasably secured, the other apparatus component bearing at least one actuating element suitable for contact-free actuation of the sensor. The apparatus may for example be a fluid power linear drive. In accordance with the invention when the clamping unit is activated it is not only the latter which is clamped inside the anchoring groove but also simultaneously the sensor housing. The clamping part is thrust from below against the undercut steps in the anchoring groove and simultaneously the supporting face of the sensor housing is thrust by the actuating part, acting on it, against the floor of the anchoring groove. The handling of the attachment means may more especially so take place that the clamping part during a rotary operatioV of the actuating part is firstly entrained owing to friction of the screw-threaded engagement and is extended laterally into an intermediate position, set by abutment means, in which it fits underneath the undercut steps in the anchoring groove. During the following further rotation of the actuating part the clamping part will screw itself upward into the clamping position for engagement with the undercut steps. Starting with the contact between the clamping part and the undercut steps the sensor housing is urged via the actuating part into the anchoring groove and against the groove's floor. The release of the anchoring engagement preferably takes place by an opposite set of movements. The abutment means limiting the outward motion of the clamping part can be constituted by the flanks of the anchoring groove. Preferably they are however a direct component of the sensor itself and are preferably located on the sensor housing and for example are constituted by the limiting face of the recess. To set the release position it is preferred to have abutment means also arranged on the sensor housing and taking effect when the clamping part is turned back toward the release position. Further advantageous developments of the invention are defined in the dependent claims. Preferably the clamping unit is held non-detachably on the sensor housing by cooperation with it. For this purpose the recess in the sensor housing may have a receiving portion for the clamping part and furthermore a neck portion adjoining same open to the top side of the sensor housing, the actuating part extending into such neck portion. The neck portion has such a cross section that the clamping part can not be moved through it. Furthermore the cross section of the neck portion is so matched to the portion, which fits into it, of the actuating part that the actuating part is trapped in the transverse direction of the sensor housing. It is preferred for the actuating part to extend coaxially into the clamping part with a screw-threaded engagement. The clamping part preferably has the actuating part extending through it. This allows a particularly simple terminal support for the actuating part. In order to provide a particularly simple rotary support means for the entire clamping unit the actuating part may, at its side facing the bottom of the recess, have a bearing socket accepting an upwardly extending bearing pin with a bearing functionality. Compared with a manner of design, in which the actuating part also has a bearing pin fitting downward into the wall of the sensor housing, which is the same in principle, particularly low height dimensions of the sensor housing may be produced. Accordingly the sensors may also be produced as well for mounting in anchoring grooves with a relatively small cross section. In the interior of the sensor housing the sensor means properly so called are located, as for example magnetoresistive sensor means or so-called reed switches. These sensor means are preferably borne by a board accommodated in the interior of the sensor housing, as for example a printed circuit board. Design with small transverse dimensions is more particularly facilitated if the board is stood on edge, that is to say with a board plane parallel to the height axis and the longitudinal axis of the sensor housing. The board can in particular be located by detent connection means in the interior of the sensor housing. It is to be recommended to associate the sensor means and the outgoing cable of the sensor with mutually opposite end parts of the sensor housing. Accordingly the sensor means may be located without hinderance by an outgoing cable and furthermore just in front of a wall. In this case it is an advantage if a narrow rib of the board extends through the intermediate section, located between the recess and the support face, and on either side there is an a respective adjoining end portion of the board, such end portion being able to have larger dimensions in the direction of the height axis than the board's rib portion, the one board portion having the sensor means and the other board terminal portion having the connection contacts for the outwardly running electrical conductors. Preferably the sensor housing comprises a hood-like principal housing body containing the board including the components arranged on it and which on the other hand is filled with a cured potting composition also functioning as a housing component. The support face for the groove floor may in this case be constituted by the potting composition. In the following the invention will be explained in detail with reference to the accompanying drawings. Figure 1 shows an apparatus composed of fluid power linear drive and a sensor with a preferred design in accordance with the invention in a partial view and in longitudinal section on the section line I - I in figure 3. Figure 2 is a perspective separate view of the sensor. Figure 3 shows a portion of the arrangement of figure 1 in a longitudinal section taken on the section line III - III with the clamping part in the clamping position, the release position of the clamping part being illustrated in chained lines to complete the picture. Figure 4 represents a cross section taken on the line IV - IV of figures 1 and 3, the clamping part being depicted in chained lines on assuming the clamping position as is also the case in figure 1 showing it in the intermediate extended position still clear of the undercut steps. The instrumentality referenced 1 comprises an apparatus 3 fitted with at least one sensor 2. The at least one sensor 2 is attached to a first (4) of two relatively moving apparatus components 4 and 5 and is activated at a predetermined relative position of such two components 4 and 5 by an actuating element 6, arranged on the second apparatus component 5, in a contact-free manner. The relative movement of the two apparatus components 4 and 5 is preferably a linear movement. The apparatus 3 is in particular a drive device and preferably such a device operated by fluid power. In the example it is a question of a fluid power linear drive, more particularly in the form of a power cylinder. In it the first apparatus component 4 is constituted by the housing of the linear drive and the second apparatus component 5 is an output drive unit moving linearly as indicated by the double arrow 7, which comprises an output drive piston 12 arranged in an interior space 8 in the housing 4. The output drive piston divides up the inner space 8 into two working chambers, which are able to be supplied via a respective fluid duct 13 and 14 in a controlled fashion with pressure medium in order to be able to move the output drive piston 5 and accordingly the entire output drive unit 5 to perform the linear movement. A force output part 15, which also belongs to the output drive unit 5 and is kinematically coupled with the output drive piston 12 and in the present case is in the form of a piston rod extending at one end from the housing 4, renders possible the tapping or output of power outside the housing 4, such output being for example being utilized for the actuation of a machine element, not illustrated. The actuation element 6 is so designed that it may operate sensor means 16 of the sensor 2 in a contact-free manner, when in this respect it assumes a particular relative position, and more especially a position radially within. Accordingly the sensor 2 is so arranged that the sensor means 16 are placed at a short distance alongside the path of movement of the actuating element 6. In the case of the actuation element 6 it is preferably a question of a permanent magnet means, as for example an annular permanent magnet arranged on the output drive piston 12. The sensor means 16 are preferably constituted by magnetoresistive sensor means or by a so-called reed switch. The sensor 2 illustrated in figure 2 separately is designed to able to be secured releasably by clamping in an undercut anchoring grooves 17 in the first apparatus component 4. The first apparatus component 4 is provided with one or more such anchoring groove 17 having a linear form and extending in parallelism to the linear movement direction 7. In each such anchoring groove 17 one or more sensors 2 may be secured in order to detect only one or more relative positions between the two apparatus components 4 and 5. The anchoring groove 17 is formed in the first apparatus component 4 and let into its outer face 18. It extends preferably along the full overall length of the first apparatus component 4, it preferably being open at its two terminal sides and having a slot-like opening 22 at its longitudinal side facing away from the first apparatus component 4. The insertion and removal of the sensor 2 in and respectively fraom the anchoring groove 17 possible in the case of the working example through the slot-like groove opening and may therefore take place, when the anchoring groove 17 is not accessible owing to a situation in a particular case of the apparatus 3 at a particular time. At this point it is to be observed that the anchoring groove 17 is not necessarily directly arranged in the first apparatus component 4. It can be a component of another carrier means, for example of a holder able to be locked on the first apparatus component 4. The anchoring groove 17 preferably has a neck 23 directly adjoining the output face 18 and constituting a slot-like groove opening, such neck being adjoined by a wider anchoring portion 25 by way of two undercut steps 24. Accordingly there is a configuration of the two longitudinal groove flanks 26 which is stepped in the depth direction of the anchoring groove 17, the undercut steps 25 extending respectively for the entire length of the groove. The anchoring groove 17 is preferably a so-called T groove or slot with a substantially T-like cross section. The anchoring portion 25 has in this case a generally square or rectangular cross section. The anchoring groove 17 furthermore possesses a base face which is preferably planar, it being termed the groove floor 17 and being opposite to the groove's neck in the depth direction of the groove. The sensor 2 may be connected via an electrical cable 28 with a control, display and/or evaluating means, not illustrated detail. The electrical cable 28 has several electrical conductors 32 which within the sensor 2 are electrically connected with the sensor means 16. Such, connection is preferably by means of electrical conductor tracks 33 on a board 34, for example a printed circuit board. The board 34 also bears the sensor means 16 and is preferably provided with pad-like connection contacts 35, on which the electrical conductors 32 are applied in an electrically conductive manner, for example by soldering or bonding using a conductive adhesive. The sensor means 16 are located, like the entire board 34 and other components arranged on it as well, in the interior of the housing (having an elongated configuration), termed the sensor housing 36, of the sensor 2. The sensor 2 may be so arranged in the anchoring groove 17 that it is completely within it and accordingly the sensor housing 3 6 does not project past the slot-like groove opening 22. For securing it stationarily within anchoring groove 17 the sensor means 36 bears a clamping unit generally referenced 37, using which the sensor 2 may be clamped within the anchoring groove 17 against the groove wall by friction. The clamping unit 37 is seated in a recess 44 in the sensor housing 36, such recess being open toward the top side 42 and to the two side faces 43 facing the groove flanks 26. Preferably the lateral openings of the recess 44 merge without interruption with the top opening 46, located of the top side 42, of the recess 44. In the direction of the longitudinal axis 47 of the sensor housing 36 the recess 44 is flanked and delimited on either side by a respective length portion 48 and 4 9 of the housing. The cable 2 8 preferably runs from the rear terminal face 39 of the sensor housing 36. The connection contacts 35 associated with it are preferably in the interior of the adjoining rear length portion 4 9 of the housing. The sensor means 16 are preferably accommodated in the housing's front length portion 48 associated with the front terminal face 38. The sensor housing 36 has a height axis 52 normal to the longitudinal axis 47. With the sensor 2 secured in the anchoring groove 17 the height axis 52 runs in the same direction as the depth direction of the groove and accordingly more particularly at a right angle to the groove's floor 27. The transverse axis 53 of the sensor housing 3 6 runs at a right angle both to the longitudinal axis 47 and also to the height axis 52. In the state mounted in the anchoring groove 17, the bottom side of the sensor housing 36 faces the groove's floor 27, and preferably constitutes a flat support face 54 which may rest on the groove floor 27 and may be supported thereon in the depth direction of the groove. The clamping unit 3 7 is able to be turned about an axis 55 of rotation, extending in the same direction as the height axis 52 of the sensor housing 36, in relation to the sensor housing 36. In this respect the clamping unit 37 is made up of two separate components, which together, independently of one another, can be turned about the axis 55 of rotation. These components comprise a clamping part 5 6 and an actuating part 57 in screw-threaded engagement therewith. The clamping part 56 possesses a central portion 58 having a central male threaded hole 62 through it and having two clamping fins 55 extending radially {as related to the axis 55 of rotation) away from it at diametrally opposite positions. The actuating part 57 has a male threaded shank portion 64 extending through the female threaded hole 62 in the clamping part 5 6 with the production of the above mentioned threaded engagement. At its downwardly turned terminal face 65 facing the support face 54 the actuating part 57 bears against the floor face 66 of the recess 44 in a downward direction. A cylindrical bearing pin 67, which runs from the floor face 66 upward toward the top opening 46 and is preferably integral with the sensor housing 3 6 fits into an also cylindrical bearing socket 68 (which is open toward the terminal face 68) in the actuating part 57. The longitudinal axes of the bearing socket 68 and of the bearing pin 67 coincide with the axis 55 of rotation. Furthermore the diameters of these components 67 and 68 are so matched with each other that the actuating part 57 remains in a state able to be rotated about the axis 55 of rotation in relation to the sensor housing 36, the components 67 and 68, which are fitted into each other, constituting the rotary bearing means responsible for this. The threaded connection between the attachment part 5 7 and the clamping part 56 is sufficiently frictional to ensure entrainment in rotation of the clamping part 56 on rotation of the actuating part 57 as long as the clamping part is not hindered by abutment means extending into its path of rotary motion. Should the clamping part 56 be hindered in its rotary movement, the simultaneous rotary actuation of the actuating part 57 will, owing to the screwing operation then occurring, cause a displacement of the clamping part 56 along the height axis 52, to wit in accordance with the direction of turning of the actuating part 57 upward or downward. Since between the actuating part 57 and the sensor housing 36 there is no screw-threaded engagement, the relative position thereof in the direction of the height axis 52 will always remain the same. Owing to the above described arrangement there is furthermore a guarantee that the actuating part 57 will never, regardless of its actual angular position, protrude downward beyond the support face 54 of the sensor housing 36. Preferably the sensor housing 36 itself directly constitutes the above mentioned abutment means 69 extending into the path of rotary movement of the clamping part 56. They are preferably constituted by two projections, which are associated respectively with one of the two side faces 4 3 and extend at this position into the lateral opening 45. Preferably they are diametrally opposite as related to the axis 55 of rotation. The one projection extends away from the front length portion 4 8 of the housing and the other projection extends from the back length portion 49 of the housing. The abutment means 69 are respectively effective in both directions of rotation of the clamping part 56. They cooperate in this case with the clamping fins 63. The latter strike, in the case of the one direction of turning, one of the projections and on rotation in the other direction strike the other projection. The recess 44 has a sufficient length in the direction of the longitudinal axis to accommodate the entire clamping part 56 when it assumes the release position indicated in figure 3 in chained lines. The clamping fins 63 then go into a retracted position in relation to the sensor housing,36 preferably not extending past the side faces 4 3 of the sensor housing 36. Accordingly the sensor 2 can, when the clamping part 56 is in the release position, be inserted without obstruction through the groove neck 23 or removed from it. The width of the sensor housing 36 as measured between the two side faces 43 is as a rule only slightly less than the width of the groove neck 23. In the release position the clamping part 65 furthermore assumes a position which is lower down in relation to the actuating part 57 and is close to or on the floor face 66 of the recess 44. In this position the clamping faces 71 facing upward and in the direction of the groove neck 23 are lower down in the anchoring groove 17 than the inner step faces 72, ' facing the groove floor 27, of the undercut steps 24. These features are fully illustrated in figure 4 in conjunction with the clamping part 56 represented in thick lines. In order to clamp the sensor 2 inserted into the anchoring groove 17 in place the actuating part 57 is manually, or with the aid of a tool if required, turned in a clamping direction 73 indicated by an arrow. In order to render possible the application of a tool the actuating part 5 7 has a tool engagement shape (for example in the form of a slot and/or a polygonal socket) at its upwardly directed top terminal portion 74, which is arranged adjacent to the top side 42. In the course of the rotation, taking place in the clamping direction 73, of the actuating part 57 firstly the clamping part 56 is moved with it, the two clamping fins 63 on opposite longitudinal sides of the sensor housing 36 being moved by rotation out of the lateral openings 45 and arriving in an extended intermediate position, in which they fit underneath the undercut steps 24 (which are only indicated in chained lines in figure 3) within the anchoring portion 25. This intermediate position is depicted in figures 3 and 4 in full lines and it will be seen that there is still a certain difference in height between the clamping faces 71 and the inner step faces 72. The outward movement of the clamping part 56 is halted by the contact between the clamping fins 63 and the abutment means 69. In order to terminate the clamping operation the actuating part 57 is however further turned in the clamping direction 73, this causing on the one hand the clamping part 56 (which is prevented from further rotation) moving upward on the shank portion 64 owing to the screw-threaded engagement until finally its clamping fins 63 engage the undercut steps 24 defining the groove neck 23. By doing up the actuating part 57 with a sufficient torque it is possible to ensure that the clamping faces 71 of the clamping fins 63 are braced against the inner step faces 72, while simultaneously the actuating part 57 (owing to contact between^ its bottom terminal face 65 and the floor face 66) thrusts downward against the sensor housing 36 and braces the same at its support face 54 against groove floor 27. It is in this manner that the sensor housing 3 6 is reliably clamped fast and does not come out of its relative position in relation to the first apparatus component 4 even when subjected vibration. The release of the clamping connection is performed by a reverse order of operations. The actuating part 57 is turned oppositely to the clamping direction 73, the bracing effect on the wall of the anchoring groove 17 firstly being released since the clamping part 56 is lowered a bit. As soon as the friction between the clamping fins 63 and the undercut steps 24 no longer suffices to lock the clamping part 56, the latter will take part in the reverse movement of the actuating part 57 owing to the friction in the thread until its clamping fins 63 have re-entered the recess 44 and owing to contact with the abutment means 69 are locked in this retracted position. It is now possible for the sensor housing 3 6 to be removed together with the complete sensor 2. As long as the two components 56 and 57 are in threaded engagement with each other the entire clamping unit 3 7 is non-detachably held on the sensor housing 36. In the case of the working example this is connected with the feature that the recess 44 has a receiving portion 76 starting with the top side 42 lower down and occupied by the clamping part 56, and an adjoining neck portion 77 (opening at the top side 42) with a cross section which is smaller than the outline of the clamping part 55 as considered on looking in the direction of the axis 55 of rotation. The neck portion 77 owing to its shape therefore prevents any upward lifting of the clamping part 56 out of position and accordingly also of the actuating part 57 which is in screw-threaded engagement with it. In order to stop the clamping unit pivoting out of the recess 44, the vertical dimensions of the of the actuating part 57 are so selected that its top and preferably head-like terminal portion 74 projects into the neck portion 77, the \ width of the neck portion 77, as considered in the direction of the longitudinal 47, being reduced toward the lateral faces 43 to a size which is smaller than the diameter of the preferably circularly shaped top terminal portion 74. Accordingly the actuating part 57 is held fast in the neck portion 77 in the direction of the transverse axis 53. A removal of the clamping unit 37 is only possible when it is taken to pieces by unscrewing the actuating part 57 into its separate components. Preferably at the top terminal portion 74 of the actuating part 57 the neck portion 77 has a shape corresponding to the latter's outline, which in the case of a circular top terminal portion 74 is a convex circular arc. Accordingly there is a further guidance for the actuating part 57 in addition to the engagement features between the bearing pin 67 and the bearing socket 58. In order to render possible narrow dimensions of the sensor housing 3 6 in the transverse direction the board 34 is stood on edge in the interior of the sensor housing 36. The plane of the board accordingly extends both in the direction of the longitudinal axis 4 7 and also in the direction of the height axis 52. This is well illustrated in figure 4 and elsewhere. Owing to the recess 4 the inner space of the sensor housing 36 only has a small height between the floor face 66 of the recess 44 and the support face 54 opposite to it. Nevertheless the board 34 appropriately extends through this intermediate section 78 as well. In order to render this possible the board 34 has a recess 79 at an edge portion. This means that the board 34 is divided up into two board terminal portions 82 and 83 lying on the near and the far face of the recess 44 in the direction of the longitudinal axis 47 and into a narrower board rib portion 84 connecting same together. The first board terminal portion 82 bears the sensor means 16 and lies inside the front length portion 48 of the housing. The other, second board terminal portion 83 of the housing has the connection contacts 3 5 and lies in the rear length portion 49 of the housing. The board rib portion 84 extends through the intermediate section 78, preferably underneath the center of the actuating part 57, so that the axis 55 of rotation extends through it. The conductor tracks 3 3 f.i. in the form of printed wiring may readily extend through the recess 44 on the board rib portion 84 without any trouble and in a restricted space. Owing to the recess 7 9 the two board terminal portions 82 and 83, as considered in the direction of the height axis 52, have a greater height than the board rib portion 84. They therefore provide a sufficient area for the installation of the sensor means 16 and the electrical conductors 32. In order to render possible particularly simple manufacture the sensor housing 3 6 preferably comprises a hood¬like principal housing body 85 defining the top side 42, the two side faces 43 and the two terminal faces 38 and 39. This principal housing body receives the board 34, fitted with all the components and already connected with the electrical conductors 32, by insertion through the bottom opening 86 of the housing. Detent means 8 7 arranged on the one hand on the board 34 and on the other hand in the interior on the wall of the principal housing body 85 render possible secure anchoring of the board 34 in place. Additional guide elements,57 not illustrated in detail ensure the desired on edge standing position of the board 34. In this fitted condition the interior space of the principal housing body is filled with a potting composition such as a hot melt adhesive, which is then cured and together with principal housing body 85 constitutes the sensor housing 36. The support face 54 can be completely or partially formed by the potting composition 88. The terminal portion of the cable 28 extending into the principal housing body 85 is also embedded in the potting composition 88, the resulting bonding providing for a means for taking strain off the cable 28. The principal housing body 85 preferably consists of plastic material and can be produced by injection molding. The clamping unit 37 preferably consists of metal. Claims 1. A sensor (2), and more particularly a position sensor, adapted for arrangement in an anchoring groove undercut in a stepped manner, comprising an elongated sensor housing (36) which at a distance from its two terminal faces (38 and 39) has at least one recess (44) open towards its top side (42) and to the two side faces (43), in which a clamping unit (37) is arranged able to be turned about an axis (55) of rotation extending in the same direction as the height axis (52) of the sensor housing (36), such clamping unit having a clamping part (56) with two diametrally opposite clamping fins (63) and an actuating part (57) serving for rotary actuation of the clamping part (56) ,- the clamping part (56) being able to be moved by rotation of the actuating part (57) between a clamping position with the clamping fins (63) extended in relation to the two side faces (43) of the sensor housing (36) and a release position with the clamping fins (63) further retracted in relation to the clamping position, characterized in that the clamping part (56) and the actuating part (57) are two separate components able to be turned about the axis of rotation (55) in relation to each other, which are in screw-threaded engagement, the actuating part (57) being rotatably supported on the sensor housing (36) without screw-threaded engagement and being simultaneously supported on the sensor housing (3 6) in a downward direction without extending past a support face (54) formed by the bottom side of the sensor housing (36) and serving for support on the floor (27) of the anchoring groove (17). 2. The sensor in accordance with claim 1, characterized by abutment means (69) on the sensor housing (36) projecting,/ into the path of rotation of the clamping part (56), such abutment means (69) setting the angular position assumed in the clamping position by the clamping part (56) in relation to the sensor housing (36). 3. The sensor in accordance with claim 1 or claim 2, characterized by abutment means (69) on the sensor housing (3 6) projecting into the path of movement of the clamping part, such abutment means setting for the clamping part (56) the angular position assumed in the release position in relation to the sensor housing (36) . 4. The sensor in accordance with claim 2 or claim 3, characterized in that the abutment means (69) are formed by projections protruding into the recess (44). 5. The sensor in accordance with any one of the claims 1 through 4, characterized in that the clamping unit (37) is held by cooperation with the sensor housing (36) on the latter in a non-detachable manner. 6. The sensor in accordance with any one of the claims 1 through 5, characterized in that the recess (44) has a receiving portion (76) accommodating the clamping part (56) and furthermore a neck portion (77) adjacent to same and opening at the top side (42) of the sensor housing (36), the actuating part (57) protruding into the neck portion (77), the neck portion (77) having a cross section preventing movement of the clamping part (56) through it in the direction of the height axis (52), such cross section furthermore being such that the actuating part (57) is trapped in it in the transverse direction of the sensor housing (3 6). 7. The sensor in accordance with any one of the claims 1 through 6, characterized in that the actuating part (57) fits into the clamping part (56) with a screw-threaded engagement and has its terminal face (65) bearing against the floor of the recess (44) . 8. The sensor in accordance with claim 7, characterized in that the actuating part (57) extends coaxially through the clamping part (56) with a screw-threaded engagement. 9. The sensor in accordance with any one of the claims 1 through 8, characterized in that the actuating part (57) has a bearing socket (68) at its bottom terminal side, into which an upwardly directed bearing pin (67) disposed on the sensor housing (36)) fits, the actuating part (57) being rotatably supported on the bearing pin (67). 10. The sensor in accordance with any one of the claims 1 through 9, characterized in that in the interior of the sensor housing (36) a board carrying the sensor means (16) of the sensor (2) is accommodated. 11. The sensor in accordance with claim 10, characterized in that the board (34) stands on edge, its plane extending both in the direction of the longitudinal axis (47) and in the direction of the height axis (52) of the sensor housing (36). 12. The sensor in accordance with claim 10 or claim 11, characterized in that the board (34) extends right through the intermediate section (78) provided between the recess (44) and the support face (54). 13. The sensor in accordance with claim 12, characterized in that the board (34) extends through the intermediate section (78) just underneath the center of the actuating part (57) . 14. The sensor in accordance with claim 12 or claim 13, characterized in that the board (34) possesses two board terminal portions (82 and 83) arranged in the longitudinal direction of the sensor housing (36) on the near and far side of the recess (44), such portions being joined together via a board rib portion (84) extending through the intermediate section (78), the board rib portion (84) having a smaller extent in the direction of the height axis (52) than at least one and preferably both board terminal portions (82 and 83). 15. The sensor in accordance with claim 14, characterized in that one or both of the board terminal portions (82 and 83) extend so far upward that they flank the recess (44) in the longitudinal direction of the sensor housing (36). 16. The sensor in accordance with claim 14 or in claim 15, characterized in that one of the board terminal portions (82) bears the sensor means (16) which are connected, by means of conductor tracks (33) running on the board rib portion (84), with connection contacts (35) disposed on the other board terminal portion (83), outgoing electrical conductors (32) being connected with the connection contacts. 17. The sensor in accordance with any one of the claims 10 through 16, characterized in that the sensor housing (36) possesses a hood-like principal housing body (85) , which accommodates the board (34) and the components (16 and 35) arranged thereon and which is filled with cured potting resin (88) surrounding the board (34). 18. The sensor in accordance with claim 17, characterized in that the board (34) is held by detent connecting means (87) in the principal housing body (85). 19. The sensor in accordance with any one of the claims a through 18, characterized in that the sensor means (16) of the sensor (2) comprise at least a reed switch or magnetoresistive sensor means. 20. An instrumentality with an apparatus (3) which has two apparatus components (4 and 5) able to be moved in relation to each other, of which the one apparatus component (4) has at least one anchoring groove (17) which is undercut in a stepped form, in which at least one sensor (2) designed in accordance with one of the claims 1 through 19 is releasably secured, the other apparatus component (5) bearing at least one actuating element suitable for contact-free operation of the sensor (2). 21. The instrumentality as claimed in claim 20, characterized in that the apparatus (3) is a fluid power linear drive.

Full Text

--A SENSOR AND AN APPARATUS FITTED THEREWITH--
The invention relates to a sensor adapted to be secured in an anchoring groove which is undercut in a stepped manner, and in particular a position sensor, comprising an elongated sensor housing having at a distance from its two terminal faces at least one recess open towards its top side and to the two side faces, and in which a clamping unit is arranged able to be turned about an axis of rotation extending in the same direction as the height axis of the sensor housing, such clamping unit having a clamping part with two diametrally opposite clamping fins and an actuating part serving for rotary actuation of the clamping part, the clamping part being able to be moved by rotation of the actuating part between a clamping position with the clamping fins extended in relation to the two side faces of the sensor housing and a release position further retracted in relation to same. The invention is furthermore directed to an instrumentality comprising at least one apparatus, as for example a fluid power linear drive, fitted with such a sensor.
One prior art device in this category is disclosed in the German patent publication DE 20211518 Ul. The sensor described in this case comprises a sensor housing with an essentially central recess, in which an integral clamping unit defining a clamping part and an actuating part is held in a rotatable manner. The clamping part has diametrally opposite clamping fins, on which radially outwardly facing clamping faces with an eccentric configuration are formed. The mounting of the sensor in an anchoring groove takes place turning with a tool so that the clamping fins, so far located in a retracted release position, are extended to the side and

assuming the clamping position are braced against the
oppositely placed groove flanks. The sensor may admittedly be
relatively simply secured. However in certain circumstances
there remains a certain clearance for movement between the
sensor housing containing the sensor means and the device
component having the anchoring groove. This may in
unfavorable circumstances, as for example vibrations, lead to
imperfect functioning.
The German patent publication DE 9414869 Ul describes an arrangement, in which a sensor is able to be secured inter alia by means of a terminally arranged two-part clamping unit in an anchoring groove. The clamping unit possesses a rotatably movable clamping part and an actuating part in screw-threaded engagement with it. By rotation of the actuating part the clamping part may be shifted into a clamping position fitting underneath the groove's neck, the actuating part being simultaneously clamped against the groove's floor. Since the sensor housing is then not reliably held in position by these means by themselves, an additional detent connection means is arranged at the opposite terminal portion of the sensor housing, something which however renders manufacture more complex.
A similar arrangement but without any detent connection means and without a pivotal clamping part is described in the Patent Abstract of Japan relating to the Japanese patent publication JP 2001280310 A.
In accordance with the German patent publication DE 196 48 679 C2 a sensor with an anchoring groove is secured by a non-rotatable clamping part, consisting of two lugs able to be spread apart by means of a screw operated spreading body.
An attachment device described in the German patent publication DE 102 31 481 B3 for a sensor comprises a clamping part operated by turning to clamp onto longitudinal ribs of an attachment groove. In the case of the German patent publication DE 203 12 472 Ul an attachment device for a sensor comprises two resiliently elastic clamping yokes for clamping

in an attachment groove.
The German patent publication DE 199 3 0 02 0 Al discloses a linear drive in which a tubular body is closed by a closure plug anchored by a security pin.
The present invention has the aim of suggesting measures for locking a sensor ensuring a simple and secure attachment in an anchoring groove which is undercut in a stepped manner.
In order to achieve such an aim in the case of a sensor of the type initially mentioned there a provision such that the clamping part and the actuating part are two separate components able to be turned about the axis of rotation in relation to each other, which are in screw-threaded engagement, the actuating part being rotatably supported on the sensor housing without screw-threaded engagement and being simultaneously supported in a downward direction without extending past a support face formed by the bottom side of the sensor housing for support on the floor of the anchoring groove.
The object is furthermore to be achieved by an instrumentality which comprises an apparatus with two apparatus components able to be shifted in relation to one another, the one apparatus component having at least one anchoring groove which is undercut in a stepped manner in which at least one sensor in accordance with the invention is releasably secured, the other apparatus component bearing at least one actuating element suitable for contact-free actuation of the sensor. The apparatus may for example be a fluid power linear drive.
In accordance with the invention when the clamping unit is activated it is not only the latter which is clamped inside the anchoring groove but also simultaneously the sensor housing. The clamping part is thrust from below against the undercut steps in the anchoring groove and simultaneously the supporting face of the sensor housing is thrust by the actuating part, acting on it, against the floor of the anchoring groove.

The handling of the attachment means may more especially so take place that the clamping part during a rotary operatioV of the actuating part is firstly entrained owing to friction of the screw-threaded engagement and is extended laterally into an intermediate position, set by abutment means, in which it fits underneath the undercut steps in the anchoring groove. During the following further rotation of the actuating part the clamping part will screw itself upward into the clamping position for engagement with the undercut steps. Starting with the contact between the clamping part and the undercut steps the sensor housing is urged via the actuating part into the anchoring groove and against the groove's floor. The release of the anchoring engagement preferably takes place by an opposite set of movements.
The abutment means limiting the outward motion of the clamping part can be constituted by the flanks of the anchoring groove. Preferably they are however a direct component of the sensor itself and are preferably located on the sensor housing and for example are constituted by the limiting face of the recess.
To set the release position it is preferred to have abutment means also arranged on the sensor housing and taking effect when the clamping part is turned back toward the release position.
Further advantageous developments of the invention are defined in the dependent claims.
Preferably the clamping unit is held non-detachably on the sensor housing by cooperation with it. For this purpose the recess in the sensor housing may have a receiving portion for the clamping part and furthermore a neck portion adjoining same open to the top side of the sensor housing, the actuating part extending into such neck portion. The neck portion has such a cross section that the clamping part can not be moved through it. Furthermore the cross section of the neck portion is so matched to the portion, which fits into it, of the actuating part that the actuating part is trapped in the

transverse direction of the sensor housing.
It is preferred for the actuating part to extend coaxially into the clamping part with a screw-threaded engagement. The clamping part preferably has the actuating part extending through it. This allows a particularly simple terminal support for the actuating part.
In order to provide a particularly simple rotary support means for the entire clamping unit the actuating part may, at its side facing the bottom of the recess, have a bearing socket accepting an upwardly extending bearing pin with a bearing functionality. Compared with a manner of design, in which the actuating part also has a bearing pin fitting downward into the wall of the sensor housing, which is the same in principle, particularly low height dimensions of the sensor housing may be produced. Accordingly the sensors may also be produced as well for mounting in anchoring grooves with a relatively small cross section.
In the interior of the sensor housing the sensor means properly so called are located, as for example magnetoresistive sensor means or so-called reed switches. These sensor means are preferably borne by a board accommodated in the interior of the sensor housing, as for example a printed circuit board. Design with small transverse dimensions is more particularly facilitated if the board is stood on edge, that is to say with a board plane parallel to the height axis and the longitudinal axis of the sensor housing. The board can in particular be located by detent connection means in the interior of the sensor housing.
It is to be recommended to associate the sensor means and the outgoing cable of the sensor with mutually opposite end parts of the sensor housing. Accordingly the sensor means may be located without hinderance by an outgoing cable and furthermore just in front of a wall. In this case it is an advantage if a narrow rib of the board extends through the intermediate section, located between the recess and the support face, and on either side there is an a respective

adjoining end portion of the board, such end portion being able to have larger dimensions in the direction of the height axis than the board's rib portion, the one board portion having the sensor means and the other board terminal portion having the connection contacts for the outwardly running electrical conductors.
Preferably the sensor housing comprises a hood-like principal housing body containing the board including the components arranged on it and which on the other hand is filled with a cured potting composition also functioning as a housing component. The support face for the groove floor may in this case be constituted by the potting composition.
In the following the invention will be explained in detail with reference to the accompanying drawings.
Figure 1 shows an apparatus composed of fluid power linear drive and a sensor with a preferred design in accordance with the invention in a partial view and in longitudinal section on the section line I - I in figure 3. Figure 2 is a perspective separate view of the sensor. Figure 3 shows a portion of the arrangement of figure 1 in a longitudinal section taken on the section line III - III with the clamping part in the clamping position, the release position of the clamping part being illustrated in chained lines to complete the picture. Figure 4 represents a cross section taken on the line IV - IV of figures 1 and 3, the clamping part being depicted in chained lines on assuming the clamping position as is also the case in figure 1 showing it in the intermediate extended position still clear of the undercut steps. The instrumentality referenced 1 comprises an apparatus 3 fitted with at least one sensor 2. The at least one sensor 2 is attached to a first (4) of two relatively moving apparatus components 4 and 5 and is activated at a predetermined

relative position of such two components 4 and 5 by an actuating element 6, arranged on the second apparatus component 5, in a contact-free manner. The relative movement of the two apparatus components 4 and 5 is preferably a linear movement.
The apparatus 3 is in particular a drive device and preferably such a device operated by fluid power. In the example it is a question of a fluid power linear drive, more particularly in the form of a power cylinder. In it the first apparatus component 4 is constituted by the housing of the linear drive and the second apparatus component 5 is an output drive unit moving linearly as indicated by the double arrow 7, which comprises an output drive piston 12 arranged in an interior space 8 in the housing 4.
The output drive piston divides up the inner space 8 into two working chambers, which are able to be supplied via a respective fluid duct 13 and 14 in a controlled fashion with pressure medium in order to be able to move the output drive piston 5 and accordingly the entire output drive unit 5 to perform the linear movement. A force output part 15, which also belongs to the output drive unit 5 and is kinematically coupled with the output drive piston 12 and in the present case is in the form of a piston rod extending at one end from the housing 4, renders possible the tapping or output of power outside the housing 4, such output being for example being utilized for the actuation of a machine element, not illustrated.
The actuation element 6 is so designed that it may operate sensor means 16 of the sensor 2 in a contact-free manner, when in this respect it assumes a particular relative position, and more especially a position radially within. Accordingly the sensor 2 is so arranged that the sensor means 16 are placed at a short distance alongside the path of movement of the actuating element 6. In the case of the actuation element 6 it is preferably a question of a permanent magnet means, as for example an annular permanent magnet

arranged on the output drive piston 12. The sensor means 16 are preferably constituted by magnetoresistive sensor means or by a so-called reed switch.
The sensor 2 illustrated in figure 2 separately is designed to able to be secured releasably by clamping in an undercut anchoring grooves 17 in the first apparatus component 4. The first apparatus component 4 is provided with one or more such anchoring groove 17 having a linear form and extending in parallelism to the linear movement direction 7. In each such anchoring groove 17 one or more sensors 2 may be secured in order to detect only one or more relative positions between the two apparatus components 4 and 5.
The anchoring groove 17 is formed in the first apparatus component 4 and let into its outer face 18. It extends preferably along the full overall length of the first apparatus component 4, it preferably being open at its two terminal sides and having a slot-like opening 22 at its longitudinal side facing away from the first apparatus component 4. The insertion and removal of the sensor 2 in and respectively fraom the anchoring groove 17 possible in the case of the working example through the slot-like groove opening and may therefore take place, when the anchoring groove 17 is not accessible owing to a situation in a particular case of the apparatus 3 at a particular time.
At this point it is to be observed that the anchoring groove 17 is not necessarily directly arranged in the first apparatus component 4. It can be a component of another carrier means, for example of a holder able to be locked on the first apparatus component 4.
The anchoring groove 17 preferably has a neck 23 directly adjoining the output face 18 and constituting a slot-like groove opening, such neck being adjoined by a wider anchoring portion 25 by way of two undercut steps 24. Accordingly there is a configuration of the two longitudinal groove flanks 26 which is stepped in the depth direction of the anchoring groove 17, the undercut steps 25 extending respectively for

the entire length of the groove.
The anchoring groove 17 is preferably a so-called T groove or slot with a substantially T-like cross section. The anchoring portion 25 has in this case a generally square or rectangular cross section.
The anchoring groove 17 furthermore possesses a base face which is preferably planar, it being termed the groove floor 17 and being opposite to the groove's neck in the depth direction of the groove.
The sensor 2 may be connected via an electrical cable 28 with a control, display and/or evaluating means, not illustrated detail. The electrical cable 28 has several electrical conductors 32 which within the sensor 2 are electrically connected with the sensor means 16. Such, connection is preferably by means of electrical conductor tracks 33 on a board 34, for example a printed circuit board. The board 34 also bears the sensor means 16 and is preferably provided with pad-like connection contacts 35, on which the electrical conductors 32 are applied in an electrically conductive manner, for example by soldering or bonding using a conductive adhesive.
The sensor means 16 are located, like the entire board 34 and other components arranged on it as well, in the interior of the housing (having an elongated configuration), termed the sensor housing 36, of the sensor 2. The sensor 2 may be so arranged in the anchoring groove 17 that it is completely within it and accordingly the sensor housing 3 6 does not project past the slot-like groove opening 22. For securing it stationarily within anchoring groove 17 the sensor means 36 bears a clamping unit generally referenced 37, using which the sensor 2 may be clamped within the anchoring groove 17 against the groove wall by friction.
The clamping unit 37 is seated in a recess 44 in the sensor housing 36, such recess being open toward the top side 42 and to the two side faces 43 facing the groove flanks 26. Preferably the lateral openings of the recess 44 merge without

interruption with the top opening 46, located of the top side 42, of the recess 44. In the direction of the longitudinal axis 47 of the sensor housing 36 the recess 44 is flanked and delimited on either side by a respective length portion 48 and 4 9 of the housing.
The cable 2 8 preferably runs from the rear terminal face 39 of the sensor housing 36. The connection contacts 35 associated with it are preferably in the interior of the adjoining rear length portion 4 9 of the housing. The sensor means 16 are preferably accommodated in the housing's front length portion 48 associated with the front terminal face 38.
The sensor housing 36 has a height axis 52 normal to the longitudinal axis 47. With the sensor 2 secured in the anchoring groove 17 the height axis 52 runs in the same direction as the depth direction of the groove and accordingly more particularly at a right angle to the groove's floor 27. The transverse axis 53 of the sensor housing 3 6 runs at a right angle both to the longitudinal axis 47 and also to the height axis 52.
In the state mounted in the anchoring groove 17, the bottom side of the sensor housing 36 faces the groove's floor 27, and preferably constitutes a flat support face 54 which may rest on the groove floor 27 and may be supported thereon in the depth direction of the groove.
The clamping unit 3 7 is able to be turned about an axis 55 of rotation, extending in the same direction as the height axis 52 of the sensor housing 36, in relation to the sensor housing 36. In this respect the clamping unit 37 is made up of two separate components, which together, independently of one another, can be turned about the axis 55 of rotation. These components comprise a clamping part 5 6 and an actuating part 57 in screw-threaded engagement therewith.
The clamping part 56 possesses a central portion 58 having a central male threaded hole 62 through it and having two clamping fins 55 extending radially {as related to the axis 55 of rotation) away from it at diametrally opposite

positions. The actuating part 57 has a male threaded shank portion 64 extending through the female threaded hole 62 in the clamping part 5 6 with the production of the above mentioned threaded engagement. At its downwardly turned terminal face 65 facing the support face 54 the actuating part 57 bears against the floor face 66 of the recess 44 in a downward direction.
A cylindrical bearing pin 67, which runs from the floor face 66 upward toward the top opening 46 and is preferably integral with the sensor housing 3 6 fits into an also cylindrical bearing socket 68 (which is open toward the terminal face 68) in the actuating part 57. The longitudinal axes of the bearing socket 68 and of the bearing pin 67 coincide with the axis 55 of rotation. Furthermore the diameters of these components 67 and 68 are so matched with each other that the actuating part 57 remains in a state able to be rotated about the axis 55 of rotation in relation to the sensor housing 36, the components 67 and 68, which are fitted into each other, constituting the rotary bearing means responsible for this.
The threaded connection between the attachment part 5 7 and the clamping part 56 is sufficiently frictional to ensure entrainment in rotation of the clamping part 56 on rotation of the actuating part 57 as long as the clamping part is not hindered by abutment means extending into its path of rotary motion. Should the clamping part 56 be hindered in its rotary movement, the simultaneous rotary actuation of the actuating part 57 will, owing to the screwing operation then occurring, cause a displacement of the clamping part 56 along the height axis 52, to wit in accordance with the direction of turning of the actuating part 57 upward or downward. Since between the actuating part 57 and the sensor housing 36 there is no screw-threaded engagement, the relative position thereof in the direction of the height axis 52 will always remain the same.
Owing to the above described arrangement there is furthermore a guarantee that the actuating part 57 will never,

regardless of its actual angular position, protrude downward beyond the support face 54 of the sensor housing 36.
Preferably the sensor housing 36 itself directly constitutes the above mentioned abutment means 69 extending into the path of rotary movement of the clamping part 56. They are preferably constituted by two projections, which are associated respectively with one of the two side faces 4 3 and extend at this position into the lateral opening 45. Preferably they are diametrally opposite as related to the axis 55 of rotation. The one projection extends away from the front length portion 4 8 of the housing and the other projection extends from the back length portion 49 of the housing.
The abutment means 69 are respectively effective in both directions of rotation of the clamping part 56. They cooperate in this case with the clamping fins 63. The latter strike, in the case of the one direction of turning, one of the projections and on rotation in the other direction strike the other projection.
The recess 44 has a sufficient length in the direction of the longitudinal axis to accommodate the entire clamping part 56 when it assumes the release position indicated in figure 3 in chained lines. The clamping fins 63 then go into a retracted position in relation to the sensor housing,36 preferably not extending past the side faces 4 3 of the sensor housing 36. Accordingly the sensor 2 can, when the clamping part 56 is in the release position, be inserted without obstruction through the groove neck 23 or removed from it. The width of the sensor housing 36 as measured between the two side faces 43 is as a rule only slightly less than the width of the groove neck 23.
In the release position the clamping part 65 furthermore assumes a position which is lower down in relation to the actuating part 57 and is close to or on the floor face 66 of the recess 44. In this position the clamping faces 71 facing upward and in the direction of the groove neck 23 are lower

down in the anchoring groove 17 than the inner step faces 72, ' facing the groove floor 27, of the undercut steps 24. These features are fully illustrated in figure 4 in conjunction with the clamping part 56 represented in thick lines.
In order to clamp the sensor 2 inserted into the anchoring groove 17 in place the actuating part 57 is manually, or with the aid of a tool if required, turned in a clamping direction 73 indicated by an arrow. In order to render possible the application of a tool the actuating part 5 7 has a tool engagement shape (for example in the form of a slot and/or a polygonal socket) at its upwardly directed top terminal portion 74, which is arranged adjacent to the top side 42.
In the course of the rotation, taking place in the clamping direction 73, of the actuating part 57 firstly the clamping part 56 is moved with it, the two clamping fins 63 on opposite longitudinal sides of the sensor housing 36 being moved by rotation out of the lateral openings 45 and arriving in an extended intermediate position, in which they fit underneath the undercut steps 24 (which are only indicated in chained lines in figure 3) within the anchoring portion 25. This intermediate position is depicted in figures 3 and 4 in full lines and it will be seen that there is still a certain difference in height between the clamping faces 71 and the inner step faces 72. The outward movement of the clamping part 56 is halted by the contact between the clamping fins 63 and the abutment means 69. In order to terminate the clamping operation the actuating part 57 is however further turned in the clamping direction 73, this causing on the one hand the clamping part 56 (which is prevented from further rotation) moving upward on the shank portion 64 owing to the screw-threaded engagement until finally its clamping fins 63 engage the undercut steps 24 defining the groove neck 23. By doing up the actuating part 57 with a sufficient torque it is possible to ensure that the clamping faces 71 of the clamping fins 63 are braced against the inner step faces 72, while

simultaneously the actuating part 57 (owing to contact between^ its bottom terminal face 65 and the floor face 66) thrusts downward against the sensor housing 36 and braces the same at its support face 54 against groove floor 27. It is in this manner that the sensor housing 3 6 is reliably clamped fast and does not come out of its relative position in relation to the first apparatus component 4 even when subjected vibration.
The release of the clamping connection is performed by a reverse order of operations. The actuating part 57 is turned oppositely to the clamping direction 73, the bracing effect on the wall of the anchoring groove 17 firstly being released since the clamping part 56 is lowered a bit. As soon as the friction between the clamping fins 63 and the undercut steps 24 no longer suffices to lock the clamping part 56, the latter will take part in the reverse movement of the actuating part 57 owing to the friction in the thread until its clamping fins 63 have re-entered the recess 44 and owing to contact with the abutment means 69 are locked in this retracted position. It is now possible for the sensor housing 3 6 to be removed together with the complete sensor 2.
As long as the two components 56 and 57 are in threaded engagement with each other the entire clamping unit 3 7 is non-detachably held on the sensor housing 36. In the case of the working example this is connected with the feature that the recess 44 has a receiving portion 76 starting with the top side 42 lower down and occupied by the clamping part 56, and an adjoining neck portion 77 (opening at the top side 42) with a cross section which is smaller than the outline of the clamping part 55 as considered on looking in the direction of the axis 55 of rotation. The neck portion 77 owing to its shape therefore prevents any upward lifting of the clamping part 56 out of position and accordingly also of the actuating part 57 which is in screw-threaded engagement with it.
In order to stop the clamping unit pivoting out of the recess 44, the vertical dimensions of the of the actuating part 57 are so selected that its top and preferably head-like

terminal portion 74 projects into the neck portion 77, the \ width of the neck portion 77, as considered in the direction of the longitudinal 47, being reduced toward the lateral faces 43 to a size which is smaller than the diameter of the preferably circularly shaped top terminal portion 74. Accordingly the actuating part 57 is held fast in the neck portion 77 in the direction of the transverse axis 53. A removal of the clamping unit 37 is only possible when it is taken to pieces by unscrewing the actuating part 57 into its separate components.
Preferably at the top terminal portion 74 of the actuating part 57 the neck portion 77 has a shape corresponding to the latter's outline, which in the case of a circular top terminal portion 74 is a convex circular arc. Accordingly there is a further guidance for the actuating part 57 in addition to the engagement features between the bearing pin 67 and the bearing socket 58.
In order to render possible narrow dimensions of the sensor housing 3 6 in the transverse direction the board 34 is stood on edge in the interior of the sensor housing 36. The plane of the board accordingly extends both in the direction of the longitudinal axis 4 7 and also in the direction of the height axis 52. This is well illustrated in figure 4 and elsewhere.
Owing to the recess 4 the inner space of the sensor housing 36 only has a small height between the floor face 66 of the recess 44 and the support face 54 opposite to it. Nevertheless the board 34 appropriately extends through this intermediate section 78 as well.
In order to render this possible the board 34 has a recess 79 at an edge portion. This means that the board 34 is divided up into two board terminal portions 82 and 83 lying on the near and the far face of the recess 44 in the direction of the longitudinal axis 47 and into a narrower board rib portion 84 connecting same together. The first board terminal portion 82 bears the sensor means 16 and lies inside the front length

portion 48 of the housing. The other, second board terminal portion 83 of the housing has the connection contacts 3 5 and lies in the rear length portion 49 of the housing. The board rib portion 84 extends through the intermediate section 78, preferably underneath the center of the actuating part 57, so that the axis 55 of rotation extends through it. The conductor tracks 3 3 f.i. in the form of printed wiring may readily extend through the recess 44 on the board rib portion 84 without any trouble and in a restricted space.
Owing to the recess 7 9 the two board terminal portions 82 and 83, as considered in the direction of the height axis 52, have a greater height than the board rib portion 84. They therefore provide a sufficient area for the installation of the sensor means 16 and the electrical conductors 32.
In order to render possible particularly simple manufacture the sensor housing 3 6 preferably comprises a hood¬like principal housing body 85 defining the top side 42, the two side faces 43 and the two terminal faces 38 and 39. This principal housing body receives the board 34, fitted with all the components and already connected with the electrical conductors 32, by insertion through the bottom opening 86 of the housing. Detent means 8 7 arranged on the one hand on the board 34 and on the other hand in the interior on the wall of the principal housing body 85 render possible secure anchoring of the board 34 in place. Additional guide elements,57 not illustrated in detail ensure the desired on edge standing position of the board 34. In this fitted condition the interior space of the principal housing body is filled with a potting composition such as a hot melt adhesive, which is then cured and together with principal housing body 85 constitutes the sensor housing 36. The support face 54 can be completely or partially formed by the potting composition 88.
The terminal portion of the cable 28 extending into the principal housing body 85 is also embedded in the potting composition 88, the resulting bonding providing for a means for taking strain off the cable 28.

The principal housing body 85 preferably consists of plastic material and can be produced by injection molding. The clamping unit 37 preferably consists of metal.

Claims
1. A sensor (2), and more particularly a position sensor, adapted for arrangement in an anchoring groove undercut in a stepped manner, comprising an elongated sensor housing (36) which at a distance from its two terminal faces (38 and 39) has at least one recess (44) open towards its top side (42) and to the two side faces (43), in which a clamping unit (37) is arranged able to be turned about an axis (55) of rotation extending in the same direction as the height axis (52) of the sensor housing (36), such clamping unit having a clamping part (56) with two diametrally opposite clamping fins (63) and an actuating part (57) serving for rotary actuation of the clamping part (56) ,- the clamping part (56) being able to be moved by rotation of the actuating part (57) between a clamping position with the clamping fins (63) extended in relation to the two side faces (43) of the sensor housing (36) and a release position with the clamping fins (63) further retracted in relation to the clamping position, characterized in that the clamping part (56) and the actuating part (57) are two separate components able to be turned about the axis of rotation (55) in relation to each other, which are in screw-threaded engagement, the actuating part (57) being rotatably
supported on the sensor housing (36) without screw-threaded engagement and being simultaneously supported on the sensor housing (3 6) in a downward direction without extending past a support face (54) formed by the bottom side of the sensor housing (36) and serving for support on the floor (27) of the
anchoring groove (17).

2. The sensor in accordance with claim 1, characterized by abutment means (69) on the sensor housing (36) projecting,/ into the path of rotation of the clamping part (56), such abutment means (69) setting the angular position assumed in the clamping position by the clamping part (56) in relation to the sensor housing (36).
3. The sensor in accordance with claim 1 or claim 2, characterized by abutment means (69) on the sensor housing (3 6) projecting into the path of movement of the clamping
part, such abutment means setting for the clamping part (56) the angular position assumed in the release position in relation to the sensor housing (36) .
4. The sensor in accordance with claim 2 or claim 3, characterized in that the abutment means (69) are formed by projections protruding into the recess (44).
5. The sensor in accordance with any one of the claims 1 through 4, characterized in that the clamping unit (37) is held by cooperation with the sensor housing (36) on the latter in a non-detachable manner.
6. The sensor in accordance with any one of the claims 1 through 5, characterized in that the recess (44) has a receiving portion (76) accommodating the clamping part (56) and furthermore a neck portion (77) adjacent to same and opening at the top side (42) of the sensor housing (36), the actuating part (57) protruding into the neck portion (77), the neck portion (77) having a cross section preventing movement of the clamping part (56) through it in the direction of the height axis (52), such cross section furthermore being such that the actuating part (57) is trapped in it in the transverse direction of the sensor housing (3 6).

7. The sensor in accordance with any one of the claims 1 through 6, characterized in that the actuating part (57) fits into the clamping part (56) with a screw-threaded engagement and has its terminal face (65) bearing against the floor of the recess (44) .
8. The sensor in accordance with claim 7, characterized in that the actuating part (57) extends coaxially through the clamping part (56) with a screw-threaded engagement.
9. The sensor in accordance with any one of the claims 1 through 8, characterized in that the actuating part (57) has a bearing socket (68) at its bottom terminal side, into which an upwardly directed bearing pin (67) disposed on the sensor housing (36)) fits, the actuating part (57) being rotatably supported on the bearing pin (67).

10. The sensor in accordance with any one of the claims 1 through 9, characterized in that in the interior of the sensor housing (36) a board carrying the sensor means (16) of the sensor (2) is accommodated.
11. The sensor in accordance with claim 10, characterized in that the board (34) stands on edge, its plane extending both in the direction of the longitudinal axis (47) and in the direction of the height axis (52) of the sensor housing (36).
12. The sensor in accordance with claim 10 or claim 11, characterized in that the board (34) extends right through the intermediate section (78) provided between the recess (44) and the support face (54).
13. The sensor in accordance with claim 12, characterized in that the board (34) extends through the intermediate section (78) just underneath the center of the actuating part

(57) .
14. The sensor in accordance with claim 12 or claim 13, characterized in that the board (34) possesses two board terminal portions (82 and 83) arranged in the longitudinal direction of the sensor housing (36) on the near and far side of the recess (44), such portions being joined together via a board rib portion (84) extending through the intermediate section (78), the board rib portion (84) having a smaller extent in the direction of the height axis (52) than at least one and preferably both board terminal portions (82 and 83).
15. The sensor in accordance with claim 14, characterized in that one or both of the board terminal portions (82 and 83) extend so far upward that they flank the recess (44) in the longitudinal direction of the sensor housing (36).
16. The sensor in accordance with claim 14 or in claim 15, characterized in that one of the board terminal portions (82) bears the sensor means (16) which are connected, by means of conductor tracks (33) running on the board rib portion
(84), with connection contacts (35) disposed on the other board terminal portion (83), outgoing electrical conductors (32) being connected with the connection contacts.
17. The sensor in accordance with any one of the claims 10 through 16, characterized in that the sensor housing (36) possesses a hood-like principal housing body (85) , which accommodates the board (34) and the components (16 and 35) arranged thereon and which is filled with cured potting resin (88) surrounding the board (34).
18. The sensor in accordance with claim 17, characterized in that the board (34) is held by detent connecting means (87) in the principal housing body (85).

19. The sensor in accordance with any one of the claims a
through 18, characterized in that the sensor means (16) of the
sensor (2) comprise at least a reed switch or magnetoresistive
sensor means.
20. An instrumentality with an apparatus (3) which has
two apparatus components (4 and 5) able to be moved in
relation to each other, of which the one apparatus component
(4) has at least one anchoring groove (17) which is undercut
in a stepped form, in which at least one sensor (2) designed
in accordance with one of the claims 1 through 19 is
releasably secured, the other apparatus component (5) bearing
at least one actuating element suitable for contact-free
operation of the sensor (2).
21. The instrumentality as claimed in claim 20,
characterized in that the apparatus (3) is a fluid power
linear drive.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=tiAFy22oCmj1/taKWk/5YA==&loc=egcICQiyoj82NGgGrC5ChA==

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Patent Number

271407

Indian Patent Application Number

5345/CHENP/2008

PG Journal Number

09/2016

Publication Date

26-Feb-2016

Grant Date

19-Feb-2016

Date of Filing

06-Oct-2008

Name of Patentee

FESTO AG & CO. KG

Applicant Address

RUITER STRASSE 82, D-73734 ESSLINGEN

Inventors:

#	Inventor's Name	Inventor's Address
1	KIESSLING, ALBERT	HALDENSTRASSE 21, D-71263 WEIL DER STADT
2	SCHNEIDER, HEIDEMARIE	OHRICHSTRASSE 66, D-73235 WEILHEIM/TECK
3	SCHUTTE, MANFRED	KROKUSWEG 1, D-73779 DEIZISAU
4	WELKER, FLORIAN	FUCHSRAIN 37, D-73061 EBERSBACH

PCT International Classification Number

G01D11/30

PCT International Application Number

PCT/EP07/01980

PCT International Filing date

2007-03-08

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	202006005609.2	2006-04-06	Germany