Title of Invention

AN IMPROVED CUTTING TOOL ASSEMBLY WITH REPLACEABLE CUTTING HEAD

Abstract

This invention relates to an improved cutting tool assembly with replaceable cutting head comprising integrally formed rear (1b, 31b) and front ( 1a, 31a) hollow shank portions, the front shank portion (1a, 31a) being elongated and being of substantially lesser radial dimensions than that of the rear shank portion (1b, 31b); a cutting head (2) releasably centered and keyed against rotation with respect to a free end of said front shank portion; and a displaceable means ( 8,15;34,35;8,44) constituting of an elongated draw rod ( 8, 35) extending through said front shank portion ( 1a, 31a) for bayonet-type coupling at one end thereof to said cutting head (2) and rigidly coupled at an opposite end thereof to a displaceable body (15, 34, 44) slidably located in said rear shank portion ( 1b, 31b) so as to be co-directionally displaceable with said draw rod (8, 35) in an axial direction of said rear shank portion (1b, 31b). A screw actuating means ( 22, 38, 45) screw mounted in said rear shank portion ( 1b, 31b) so as to bear on said displaceable body ( 15, 34, 44) such that screw rotation of said means (22, 38, 45) in opposite directions results in displacement of said body (15, 34, 44) respectively away from and towards said cutting head (2) so as respectively to clamp and release said cutting head (2) to and from said front shank portion (1a, 31a).

Full Text

-1A- FIELD OF THE INVENTION The present invention relates to an improved cutting tool assemble with replaceable cutting head. BACKGROUND OF THE INVENTION Such miniature cutting tools are in general used for internal machining such as, for example, in turning, milling, grooving, drilling, etc. Additionally, such tools can be used for external machining such as, for example, milling. These tools are in general constituted by a hollow shank of which a front, elongated shank portion is of relatively small diameter (for example, 6 to 14 mm). In general, the cutting head is releasably screw coupled to a front leading end of the front shank portion. Such a tool is disclosed, for example, in International Application Serial No. WO 94/23874. With such an configaration the coupling screw must be capable of withstanding the torque load arising out of the axial pre-load originating with the screw mounting of the cutting head on the front shank portion. With increasing reduction in size of the cutting head, smaller and smaller coupling screws have to be used, with consequent danger of the screw being sheared off as the torque forces increase. In addition, the use of such small screws requires equally small turning keys. It will be realized that with such small keys the tightening force which can be exerted is very limited. Such small keys are also subject to easy-fracture and wear. -2- Replacement and fitting of the cutting head involves handling of the screw which can be very diminutive, and it can readily fall and get lost, as is also the case with the very small cutting heads and tightening keys. It has been proposed in DOS 3402547 to produce a cutting tool wherein the cutting head continues to be screw coupled to the front tool shaft but wherein, by virtue of the fact that radially formed ribs on an undersurface of the cutting head mate within correspondingly radially formed grooves on the adjacent surface of the front shaft, the rib and groove arrangement take up the torque forces and this, of course, reduces the stress on the coupling screw. Nevertheless, the use of such a coupling screw, and especially a diminutive screw, is subjected to the disadvantages referred to above. In an alternative embodiment of a cutting tool disclosed in DOS 4026651 the cutting head is fitted to the tool holder via an elongated draw rod which extends through the front shaft portion into a hollow region in the rear shaft portion and is effectively keyed against rotation with respect to the shaft. The draw rod is coupled to a gripping mechanism located in the rear shaft portion and accessible therefrom for retaining the cutting head against the front shaft portion or for displacing it away therefrom. Here, torque forces are taken up by the relatively narrow draw rod adjacent the front end of the shaft, whilst retention and release of the cutting head is by way of a relatively complicated gripping mechanism. It is an object of the present invention to provide a new and improved miniature cutting tool wherein the above-referred-to difficulties and disadvantages in coupling and uncoupling the cutting head to the cutting tool are significantly reduced, BRIEF SUMMARY OF THE INVENTION According to the present invention there is provided a miniature cutting tool comprising integrally formed rear and front hollow shank portions, the front shank portion being elongated and being of substantially lesser radial dimensions than that of the rear shank portion; a cutting head -3- releasably centered and keyed against rotation with respect to a free end of said front shank portion; an elongated draw rod extending through said front shank portion for bayonet-type coupling at one end thereof to said cutting head and rigidly coupled at an opposite end thereof to a body slidably located in said rear shank portion so as to be co-directionally displaceable with said draw rod in an axial direction of said rear shank portion; and screw actuating means screw mounted in said rear shank portion so as to bear on said displaceable body that screw rotation of said means in opposite direction results in displacement of said body respectively away from and towards said cutting head so as respectively to clamp and release said cutting head to and from said front shank portion. Preferably, spring biassing means are provided to spring bias the body towards the cutting head into releasing the cutting head from the front shank portion, said screw actuating means comprising a screw having an inner end bearing on said body so that inwardly directed screw rotation of the screw imparts to the body a displacement away from said cutting end and against the spring biassing. In accordance with a additional preferred embodiment of the invention, the axially displaceable body is formed with a transversely extending cavity having oppositely sloping cam follower surfaces located at transversely spaced apart locations of the cavity, the screw actuating means comprising an elongated cam member extending through the cavity and being formed at transversely spaced apart locations thereof with oppositely sloping cam surfaces in respective sliding relationship with the cam follower surfaces, the screw actuating means being screw displaceable inwardly and outwardly in the cavity so as to give rise to relative sliding displacements of juxtaposed pairs of cam and cam follower surfaces with consequent displacement of the body member towards and away from the cutting head. With the latter embodiment, the cam follower surfaces respectively define a pair of transversely spaced apart conical recesses comprise within the cavity, the cam surfaces being respectively constituted by a pair of transversely spaced apart conical surfaces of the cam member. -4- With a miniature cutting tool in accordance with the invention, the fact that the cutting head is keyed to the front shaft portion means that all torque forces are taken up by this front shaft portion and not by any intermediate screw coupling. The entire mechanism for ensuring the effective clamping and releasing of the cutting head from the front shank portion is located in a readily accessible location in the rear shank portion and, by virtue of a simple screw motion, in one sense effective clamping of the cutting head against the front shaft portion is effected, whilst screw motion in the opposite direction ensures the release of the cutting head from the front shaft portion, either under the influence of a compression spring or by virtue of relative movement of a cam follower on a cam surface. By virtue of the fact that retention of the cutting head on the draw rod is by way of a bayonet-type coupling, release of the cutting head from the draw bar can be effected by a simple rotary motion, without the problems involved in releasing and retaining a screw of diminutive size. BRIEF DESCRIPTION OF/DRAWINGS For a better understanding of the present invention and to show how the same may be carried out in practice, there will now be described a miniature cutting tool in accordance with the present invention, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a first form of an assembled miniature cutting tool in accordance with the present invention; Fig. 2 is a partially sectioned, perspective view of the tool shown in Fig. 1; Fig. 3 is an exploded view of the miniature tool shown in Figs. 1 and 2; Fig. 4 is a perspective view of the shank of the tool shown in the preceding figures; Fig. 5 is a perspective view from below of the cutting head incorporated in the tool shown in the preceding drawings; -5 - Fig. 6 is a longitudinally sectioned perspective view of a part of a modified form of miniature cutting tool in accordance with the present invention; Fig. 7 is a longitudinally sectioned view of the portion of the cutting tool shown in Fig. 6; Fig. 8 is a view corresponding to that shown in Fig. 7 with an axially displaceable body thereof displaced to the right; Fig. 9 is a longitudinally sectioned view of part of a still modified form of cutting tool in accordance with the invention; and Fig. 10 is a side elevation, partially longitudinally sectioned exploded view of the cutting tool shown in Fig. 6. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS As seen in Figs. 1, 2 and 3 of the drawings, a miniature cutting tool designed, for example, for use in internal machining comprises a shank 1 having a front tubular shank portion 1a formed integrally with a rear hollow, cylindrical shank portion 1b the front shank portion 1a being of significantly lesser radial dimensions than the rear shank portion 1b. As can be clearly seen from Figs. 2, 3, 4 and 5 of the drawings, a cutter head 2 having a radially extending cutter blade 3 is formed on a base surface thereof with three radially distributed, dome-like keying projections 4 which are designed to fit into correspondingly formed, dome-like radially distributed keying recesses 5 formed in a terminal edge of the front shank portion 1a such that, when the cutting head 2 is fitted against the terminal edge of the front shank portion 1a it is centered with respect to the front shank portion 1a and keyed against relative rotation with respect thereto. The cutting head 2 which comprises, in addition to the cutting blade 3 and the keying projections 4, an essentially cylindrical body portion 6, has formed on an inner wall thereof a plurality of radially spaced-apart, peripherally located, inwardly directed flanges 7. -6- An elongated draw rod 8 is formed at one end thereof with a plurality of radially extending wings 9 which lie on a circle smaller than the inner diameter of a cylindrical cavity formed in the body member 6, each wing having a peripheral extent such as to allow for ready introduction between the peripheral flanges 7. The elongated draw rod 8 comprises a first portion 10 adjacent the wing portion 9 of substantially cylindrical shape. A central, elongated, threaded portion 11 and a terminal portion 12 of substantially polygonally cross-sectional shape. An elongated, axially displaceable body member 15 is formed with a through-going threaded bore 16 through which the draw rod 8 can be screw inserted and is formed with a pair of opposite circular cylindrical surfaces 17 and an opposite pair of substantially planar side surfaces 19. Formed in a leading end surface 20 of the body member 15 is a radially extending groove 21. The groove 21 is advantageously of V-shaped cross-section, whether, as shown in the figure, with a substantially flat base or otherwise. Such a shape is particularly useful in preventing undesired screw release during cutting. The shank 1 is provided with an intermediate portion 22 which separates the front shank portion 1a from the rear shank portion 1b there being formed in the intermediate portion 22 a threaded aperture 22a into which can be screwed an adjustable screw 23. The assembly is vague provided with a compression spring 24 which fits on to the terminal portion 12 of the draw rod 8 and an abutment, constituted in this embodiment by a clevis-type clip 25 insertable into the rear shank portion 1b via an aperture 26 which serves to retain the spring in a compressed condition. As seen in Fig. 3, assembly of the cutting tool can take place as follows. The draw rod 8 is introduced via its terminal portion 12 into the shank 1 through the open end of the front shank portion la. The body portion 15 is introduced into the rear shank portion 1b via its open end. The -7- draw rod is thereupon screwed into the threaded bore 16 of the body portion until its terminal portion 12 projects therefrom. At the same time, the screw 23 is introduced through the bore 22a so that its tip is located within the groove 21, thereby delimiting the displaceability of the body portion 15 towards the terminal grooved portion of the front shank portion 1a. The spring 24 is inserted into the rear shank portion 1b is held compressed and the clip 25 the spring 24 is then inserted into the rear shank portion 1b through the| aperture 26 and threaded over the terminal portion 12 of the draw rod 8, maintaining the spring 24 in its compressed condition. Preferably the rotation of the body member 15 into a position wherein the groove 21 is located opposite the aperture 22a, and the compression of the spring 24 prior to insertion of the clip 25 is effected using a dedicated prong-like key (not shown). In this condition, with the body portion 15 and the draw rod 8 biassed outwardly by the compression spring 24, the radial wings 9 project slightly beyond the terminal grooved end portion of the front shank portion 1a The cutting head can now be placed in its proper position over the radial wings 9, pressed down against the end of the front shank portion and rotated until the keying projections 4 enter the keying recesses 5, In this position, the cutting head 2 is locked against withdrawal by the bayonet-type fitting of the wings 9 and the interposed flanges 7. If now the screw 23 is screwed inwardly against the surface of the groove 21 of the body member 15, the latter is displaced in a direction away from the cutting head '2 against the biasing force exerted by the compression spring 24; thereby drawing the co-directionally- displaceable draw rod 8 inwardly and effectively clamping the cutting head 2 against the grooved end of the' front shank portion (la) the inter-engagement of the projections 4 of the cutting head 2 in the grooves 5 of the front shank portion 1a effectively keying the cutting head 2 against rotation. In this way, torque forces exerted on the cutting head 2 during the cutting operation are not transmitted to the draw bar 8 but are taken up by the much more massive front shank portion 1a. -8- When it Is now required to replace the cutting head 2, all that is required is to unscrew slightly the screw 23, thereby releasing the body portion 15 for slight displacement under the influence of the compression spring 24 in the direction of the cutting head 2, whereupon the cutting head 2 is displaced away from the grooved end of the front shank portion 1a and can be readily released by a simple rotational movement and detached from the draw rod 8. This replacement of the cutting head can be effected using one hand without the necessity to remove the screw 23 from the shank. This is clearly distinctly advantageous when compared with prior art tools which require two-handed operation and the requirement to safeguard against loss of the wholly removed small securing screw. The provision of the axially displaceable body member 15 with an opposite pair of substantially planar side surfaces 19 allows for the passage of cooling fluid through the rear shank portion 1b in the regions between the planar side surfaces l9 and the inner surface of the rear shank portion 1b. In the embodiments shown in Figs. 6 through 10 of the drawings, the cutting tool comprises a shank 31 having a front tubular shank portion 1a formed integrally and coaxially with a rear hollow, cylindrical shank portion 31b the front shank portion 31a being of significantly lesser radial dimensions than those of the rear shank portion 31b. Extending through diametrically opposite portions of the cylindrical wall of the rear shank portion 31b are bore holes 32a and 32b respectively communicating with the inner cylindrical hollow interior 33 of the rear hollow cylindrical shank portion 31b, with the bore 32a internally threaded. An elongated, substantially cylindrical body member 34 is axially slidable in the region 33 within the rear shank portion 31 and is coupled integrally at the end thereof closest to the front shank portion 31a with an elongated draw rod 35 which corresponds in shape and function with the draw rod 8 described with reference to the preceding drawings. -9- A throughgoing, transversely directed bore 36 is formed in the member 34,- having a pair of oppositely sloping cam surfaces 37a and 37b, which form part of the defining surfaces of the throughgoing bore 36. Essentially, and as can be seen most clearly, for example, in Fig. 10 of the drawings, the throughgoing bore 36 comprises a central portion 36a and upper and lower pseudo conical portions 36b and 36c which are essentially asymmetrically disposed with respect to the central portion 36a, with the surfaces 37a and 37b partially defining the pseudo conical recesses 36b and 36c. Screw actuating means 38 comprises a central, cylindrical connecting portion 39 having an upper screw threaded portion 40 which is formed integrally with the central portion 39 via a conically tapering portion 41 and having a lower cylindrical portion 42 which is formed integrally with the central portion 39 via a conically tapering portion 43. As seen most clearly in Figs. 6 to 10 of the drawings, the screw actuating member 38 is located within the rear shank portion 31b, with the upper screw threaded portion 40 screw threadingly fitted within the screw threaded bore 32a and the lower cylindrical portion 42 slidingly fitted within the lower bore 32b. The central connecting portion 39 is located within the central portion 36a of the transverse bore 36 with the conical surface of the conically tapering portion 41 bearing against the sloping surface 37a and the conical surface of the conically tapering portion 43 constituting a sloping surface bearing against the sloping surface 37b. When the screw actuating member 38 has been screwed outwardly into the position shown in Fig. 7 of the drawings, the sloping surface of the conically shaped portion 43 bears against the sloping surface 37b and gives rise to a leftwardly directed movement of the body member 34 and a consequent displacement of the cutter head 2 from the adjacent surface of the front shank portion la (not shown in this figure). When, however, the screw actuating member is screwed inwardly into the position shown in Fig. 8, the cam follower surface of the conically - 10- tapering portion 41 bears on the sloping cam surface 37a, causing the body member 34 to move to the right, with a consequently rightwardly directed movement of the draw rod 35 which, in its turn, gives rise to effective clamping of the cutter head against the adjacent surface of the front shaft portion la. In an alternative embodiment shown in Fig. 9 of the drawings, the basic construction of an axially displaceable body 44 and a screw adjusting member 45 are the same as previously described with reference to the preceding drawings, but in this case both a transverse bore 46 in the displaceable body 44 and the screw adjusting means 45 are disposed at an acute angle with respect to the longitudinal axis of the tool, the advantage here being that readier access can be had to the screw adjusting means 45 for rotation thereof and consequent displacement of the body 44. Reference will once more be made to Fig. 10 of the drawings for a more detailed description of the construction, mode of assembly and insertion of the screw actuating means 38 into the rear shank portion 31b in general, and through the body 34 in particular. As seen in Fig. 10, the screw actuating means 38 is essentially formed of two separate component parts 38a and 38b, wherein a first component 38a consists of the upper screw threaded portion 40, the conically tapering portion 41 and the central cylindrical connecting portion 39, from which depends integrally a split coupling pin 51 having upper and lower portions 51a and 51b, with the lower portion 51b being of slightly extended radial dimensions as compared to the upper portion 51a and merging therewith via a shoulder 51c. The second component 38b consists of the lower cylindrical portion 42 and the tapering portion 43 having a central bore 52 consisting of upper and lower portions 52a and 52b, with the lower portion 52b being of larger radial dimensions than the portion 52a, the axial extent of the portion 52a being not less than the axial extent of the portion 51a of the coupling element 51. -11 - For the purpose of assembly, the axially displaceable body 34 is located within the internal cavity 33 of the rear shank portion 31b, with the laterally directed bore 36 thereof 36 opposite the diametrically opposed bores 32a and 32b formed in the rear shank portion 31b. The screw actuating component 38a is introduced into the rear shank portion 31b via the bore hole 32a, and through the transverse bore 36 and the coupling pin 51 thereof snapped into position within the second screw actuating component 38b. It is, however, clear that other equivalent means can be employed for assembling the screw actuating means 38. The means just described with reference to Figs. 6 to 10 of the drawings can be used for selective displacement of a cutting head into and out of clamping engagement with an adjacent surface of a front shank portion irrespective of the manner in which the cutter head is secured to the associated draw rod. The invention as specifically described by way of example with respect to the illustrated embodiments can equally well be applied to miniature cutting tools for both internal and external machining. These means can be employed in tools of other kinds for effecting controlled limited displacements of tool elements. 12 We Claim: 1. An improved cutting tool assembly with replaceable cutting head comprising integrally formed rear (lb, 31b) and front ( la, 31a) hollow shank portions, the front shank portion (la, 31a) being elongated and being of substantially lesser radial dimensions than that of the rear shank portion (lb, 31b); a cutting head (2) releasably centered and keyed against rotation with respect to a free end of said front shank portion; and a displaceable means ( 8,15;34,35;8,44) constituting of an elongated draw rod ( 8, 35) extending through said front shank portion ( la, 31a) for bayonet-type coupling at one end thereof to said cutting head (2) and rigidly coupled at an opposite end thereof to a displaceable body (15, 34, 44) slidably located in said rear shank portion ( lb, 31b) so as to be co-directionally displaceable with said draw rod (8, 35) in an axial direction of said rear shank portion (lb, 31b), characterized in that a screw actuating means ( 22, 38, 45) screw mounted in said rear shank portion ( lb, 31b) so as to bear on said displaceable body ( 15, 34, 44) such that screw rotation of said means (22, 38,45) in opposite directions results in displacement of said body (15, 34, 44) respectively away from and towards said cutting head (2) so as respectively to clamp and release said cutting head (2) to and from said front shank portion (la, 31a). 2. The assembly as claimed in claim 1, wherein spring biasing means (24) is provided to spring bias said body (15) towards said cutting head (2) into releasing said cutting head (2) from said front shank portion (la) and wherein said screw actuating means (22) comprises a screw (23) having an inner end bearing on said body (15) so that inwardly directed screw rotation of said screw (23) imparts a displacement to said body (15) away from said cutting head against the spring biasing. 3. The assembly as claimed in claim 2, wherein a grooved portion(21) is formed in a leading, end (20) of said body (15) into which the inner end of said screw (23) fits. 4. The assembly as claimed in claim 2 or 3, wherein said body (15) is screw mounted on said draw rod (8) which projects beyond said body, the compression spring (24) being mounted on the projecting portion (12) of said draw rod (8) and bearing on one end thereof on said body (15) and at an opposite end thereof on an abutment member (25) fixed with respect to said rear shank portion (la). 5. The assembly as claimed in claim 4, wherein said abutment member (25) is a clip (25) transversely insertable into said rear shank portion (la) so as to engage said projecting portion. 13 6. The assembly as claimed in claim 1, wherein said body (34) is formed with a transversely extending cavity (36) having oppositely sloping follower surfaces (41, 43) located at transversely spaced apart locations of said cavity (36) and wherein said screw actuating means (38) comprises an elongated member (34) extending through said cavity (36) and being formed at transversely spaced apart locations thereof with oppositely sloping surfaces ( 37a, 37b) in respective sliding relationship with said follower surfaces ( 41, 43) said screw actuating means (38) being screw displaceable inwardly and outwardly in said cavity (36) so as to give rise to relative sliding displacements of juxtaposed pairs of follower surfaces ( 37b, 43) with consequent displacement of the body member (34) towards and away from the cutting head (2). 7. The assembly as claimed in claim 6, wherein said follower surfaces (41, 43) respectively define a pair of transversely spaced apart conical recesses(36b,36c) accommodated within said cavity (36) and wherein said surfaces (37a, 37b) are respectively constituted by a pair of transversely spaced apart conical surfaces of said member (38). 8. The assembly as claimed in claim 6 or 7, wherein one of said conical surfaces (41) |s formed on a detachable cam member component (42) which can be releasably coupled to the remaining portion (39) of the cam member (38). 9. A cutting tool as claimed in one of claims 6, 7 or 8, wherein one end portion (40) of said member (38) is formed with screw threading so as to screw engage with an internally threaded extremity of said cavity (36). 10. A cutting tool as claimed in any one of the preceding claims, wherein adjacent surfaces of said cutting head (2) and front shank portion (la) are respectively formed with inter-engaging recess (5) and projection means (4) so as to ensure said keying and centering. 11. A cutting tool as claimed in any one of the preceding claims, wherein said one end of said draw rod (8) is formed with a plurality of radially extending wings (9) and wherein said cutting head (2) is formed with an open ended cavity (5) having a set of radially spaced apart, peripherally located, inwardly directed flanges (7), the configuration being such that said bayonet-type coupling is effected upon insertion of said one end of the draw rod (8) into said cutting head cavity (5) with said wings (9) passing respectively between successive flanges (7) and rotating said head (2) with respect to said draw rod (8) so that said wings (9) rest on said flanges (7). 14 12. The assembly as claimed in claim 1, wherein said displacement means (34, 35) comprises an axially displaceable body (34) slidably located in a cylindrical shank portion (31b); and a displacement member (35) coupled to said body (34); a transversely extending cavity (36) formed in said body (34) and having oppositely sloping cam follower surfaces (41, 43) located at transversely spaced apart locations of said cavity (36); an elongated member (38) extending through said cavity (36) and being formed at transversely spaced apart locations thereof with oppositely sloping surfaces (37a, 37b) in respective sliding relationship with said earn follower surfaces (41, 43); and means (23) for selectively displacing said member (38) into and out of the cavity (36) so as to displace the body member (34) in opposite directions. OF L.S.DAVAR & CO. APPLICANTS' AGENT Dated this 9th day of SEPTEMBER ((1997 This invention relates to an improved cutting tool assembly with replaceable cutting head comprising integrally formed rear (1b, 31b) and front ( 1a, 31a) hollow shank portions, the front shank portion (1a, 31a) being elongated and being of substantially lesser radial dimensions than that of the rear shank portion (1b, 31b); a cutting head (2) releasably centered and keyed against rotation with respect to a free end of said front shank portion; and a displaceable means ( 8,15;34,35;8,44) constituting of an elongated draw rod ( 8, 35) extending through said front shank portion ( 1a, 31a) for bayonet-type coupling at one end thereof to said cutting head (2) and rigidly coupled at an opposite end thereof to a displaceable body (15, 34, 44) slidably located in said rear shank portion ( 1b, 31b) so as to be co-directionally displaceable with said draw rod (8, 35) in an axial direction of said rear shank portion (1b, 31b). A screw actuating means ( 22, 38, 45) screw mounted in said rear shank portion ( 1b, 31b) so as to bear on said displaceable body ( 15, 34, 44) such that screw rotation of said means (22, 38, 45) in opposite directions results in displacement of said body (15, 34, 44) respectively away from and towards said cutting head (2) so as respectively to clamp and release said cutting head (2) to and from said front shank portion (1a, 31a).

Documents:

01659-cal-1997-abstract.pdf

01659-cal-1997-claims.pdf

01659-cal-1997-correspondence.pdf

01659-cal-1997-description(complete).pdf

01659-cal-1997-drawings.pdf

01659-cal-1997-form-2.pdf

01659-cal-1997-form-3.pdf

01659-cal-1997-from-1.pdf

01659-cal-1997-p.a.pdf

1659-CAL-1997-FORM-27-1.pdf

1659-CAL-1997-FORM-27.pdf

1659-cal-1997-granted-abstract.pdf

1659-cal-1997-granted-claims.pdf

1659-cal-1997-granted-correspondence.pdf

1659-cal-1997-granted-description (complete).pdf

1659-cal-1997-granted-drawings.pdf

1659-cal-1997-granted-examination report.pdf

1659-cal-1997-granted-form 1.pdf

1659-cal-1997-granted-form 2.pdf

1659-cal-1997-granted-form 3.pdf

1659-cal-1997-granted-letter patent.pdf

1659-cal-1997-granted-pa.pdf

1659-cal-1997-granted-reply to examination report.pdf

1659-cal-1997-granted-specification.pdf

1659-CAL-1997-OTHERS.pdf