CAM LOCK FOR TOOL ELEMENTS

Abstract: A locking cam for locking a pair of tool elements together. The locking cam member (12) is rotatably mounted in one (30) of the tool elements such that a clamping surface engages a female gib surface (24) formed on the other (22) tool element. Clamping screws (40) exert a rotative force on the cam member so as to bring the clamping surface into contact with the female gib surface and forceably lock the tool elements (30) (22) together.

Description: CA LOCK FOR TOOL ELEMENTS BACKGROUND OF THE INVENTION It is well known to use male and female gibs to form dove tail joints to slidably attach one tool element to another. While this structure readily facilitates the linear adjustment of one of the elements with respect to the other, it poses problems in regard to the clamping of the elements together in a desired position. It is known to provide an adjustment screw rotatably attached to one of the elements and threadingly engaging the other to facilitate their mutual adjustment and to hold them in position once they are adjusted. However, vibrations imparted to the elements in their normal usage will usually cause the adjustment screw to rotate, thereby altering the respective positions of the elements. It is also known to utilize clamping screws engaging one of the elements and bearing against the other. However, due to the clearances necessary to allow the elements to slide with respect to one another, such clamping screws typically raise one of the elements with respect to the other, it poses problems in regard to the clamping of the elements together in a desired position. It is known to provide an adjustment screw rotatably attached to one of the elements and threadingly engaging the other to facilitate their mutual adjustment and to hold them in position once they are adjusted. However, vibrations imparted to the elements in their normal usage will usually cause the adjustment screw to rotate, thereby altering the respective positions of the elements. It is also known to utilize clamping screws engaging one of the elements and bearing against the other. However, due to the clearances necessary to allow the elements to slide with respect to one another, such clamping screws typically raise one of the elements out of contact with the broad, bottom surface of the dove tail groove and place undue stresses on the angled sides formed by the gibs. When utilized in tools which must operate under severe load conditions, the useful life of the tool elements can be markedly reduced by such stresses. Clamping screws entering the elements laterally must bear against one of the angled sides forming the gibs and, therefore, do not achieve an adequate clamping force. In order to increase the clamping force, it has become necessary to utilize a large number of clamping screws, thereby rendering the adjustment of the relative positions of the tool elements a time consuming and uneconomical process. SUMMARY OF THE INVENTION The present invention relates to a cam lock for clamping tool elements together in a desired orientation. The cam lock acts on the inclined surface of a female gib formed on one side of a groove in one of the tool elements. The other tool element is slidably received in the groove such that, as the cam lock is rotated, it exerts a force on the second tool element to force it against the opposite side of the groove as well as the base of the groove. The cam lock acts on a significant surface area of the gib so as to distribute the stresses over a maximum area. Furthermore, by urging the second tool element in contact with both the opposite side of the groove and the base of the groove, it enables the tool elements to be utilized under severe working conditions while maintaining them in their clamped positions. The cam lock element is rotatably mounted within the second of the tool elements and defines a clamping surface and a force receiving surface. The clamping surface bears against the inclined side of the female gib, while the force receiving surface bears against the inclined side of the female gib, while the force receiving surface bears against an end of a force element, such as a threaded screw, which exerts a rotative force on the cam member. BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a front view of the locking cam member according to the invention. FIGURE 2 is a top view of the locking cam member shown in FIGURE 1. FIGURE 3 is a cross-sectional view of the locking cam member taken along line A-A in FIGURE 1. FIGURE 4 is a side view of the locking cam member shown in FIGURE 1. FIGURE 5 is a front view of tool elements incorporating the locking cam member according to the invention. FIGURE 6 is a side view of the tool elements shown in FIGURE 5. FIGURE 7 is a cross-sectional view of the tool elements taken along line B-B in FIGURE 5. FIGURE 8 is a side view of a portable lathe incorporating the tool elements shown in FIGURES 5-7. FIGURE 9 is a side view, similar to FIGURE 6, showing an alternative tool holding member. FIGURE 10 is a side view, similar to FIGURE 6, showing a second alternative tool holding member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The locking cam member 10 according to the invention is shown in Figures 1-4 and comprises a generally cylindrical body 12 having a longitudinal axis 14. Cylindrical body 12 defines a clamping surface 16 which extends substantially radially from longitudinal axis 14, as shown in Figures 3 and 4. A pair of force receiving surfaces 18 are also formed on the cylindrical body 12. Although the invention will be described as incorporating a pair of such force receiving surfaces, it is to be understood that more or less of these surfaces may be utilized without exceeding the scope of the invention. The exact number will vary according to the overall length of the locking cam member and the amount of clamping force that is required.. As shown in Figure 3 the force receiving surfaces 18 also extend substantially radially outwardly from the longitudinal axis 14 and define an included angle with the clamping surface 16. Angle**, is an obtuse angle and may be on the order of 150°. Clamping surface 16 defines an angle T with respect to surface 20, which angle is approximately 90°. The locking cam member 10 is shown in its operative positions in Figures 5-7. A first tool element 22, which may be a mounting bracket or the like, defines a groove having a first side forming a female gib 24, a groove bottom 26 and a second, opposite side 28. As is well known in the art, female gib 24 defines an acute angle with bottom 26 as shown in Figure 7. A second tool element 30 is slidably received in the groove defined by tool element 22 such that it may be moved in a direction along axis 32, shown in Figure 5. To facilitate this adjustment, adjusting screw 34 is rotatably mounted to bracket 36 which, in turn, is attached to tool element 22. Adjusting screw 34 threadingly engages tool element 30 such that rotation of knob 38 causes tool element 30 to traverse along axis 32. Locking cam member 10 is rotatably mounted within tool element 30 such that its longitudinal axis 14 extends generally parallel to the direction of motion along axis 32. A pair of clamping screws 40 are threaded into tool element 30 such that their ends contact force receiving surfaces 18. As clamping screws 40 are threaded inwardly against the force receiving surfaces 18, the locking cam member 13 is caused to rotate about longitudinal axis 14 in a counterclockwise direction as indicated by arrow 42 in Figure 7. Such rotation brings clamping surface 16 into contact with female gib 24 thereby exerting a force on tool element 30 causing it to move into engagement with bottom 26 and side 28 of the groove. The stresses imparted to tool element 30 during the tool operation are distributed over the contact area with bottom 26 and the side 28 of the groove, as well as the contact area between clamping surface 16 and female gib 24. Tool element 30 may have a cutting tool 44 attached thereto via tool clamping screws 46, as shown in Figure 7. Tool 44 typically has a cutting edge 48 which bears against the surface of the article to be machined or cut. Tool element 22 may also define a plurality of holes 50 to accommodate screws 52 or the like so as to attach the tool element to a machining tool or the like. Although the locking cam member according to the invention may be utilized with any type of tool, it has found particular application in conjunction with a portable lathe. Portable lathes, per se, are well known in the art and, as shown in Fig. 8, typically comprise a mandrel 54 having an expansible wedge mechanism 56 at one end to attach it to the interior of a pipe 58. Wedge clamping elements 60 expand radially outwardly to grip the interior of pipe 58. Figure 8 shows only one such clamping member, however, it is understood that such members are usually equally -6- circumferentially spaced about the wedge mechanism 56 to provide a uniform clamping force. The portable lathe also includes a cutting head 62 which may have a drive motor 64 attached thereto so as to rotate a cutting wheel 66. The tool element 22 is typically attached to the face of the cutting wheel 66 via bolts 52. Second tool element 30 is adjusted with respect to tool element 22 so as to bring cutting tool 44 into proper alignment with the end of pipe 58. Once the proper alignment has been achieved, clamping screws 40 are tightened so as to rotate the locking cam member 10 and to rigidly affix tool member 30 in its desired position. The cutting head 62 is fed. toward the end of pipe 58 so as to bring the cutting tool 44 into contact therewith by manual manipulation of feed mechanism 68. The specific details of the portable lathe such as the wedge clamping mechanism, the rotating mechanism, the cutting head and the feed mechanism form no part of this invention, and reference is made to U.S. Patent 4,422,356 to Pertle and U.S. Patent No. 4,437,366 to Astle for typical examples of portable lathe structures. The clamping member according to this invention may be utilized with any type of machine tool structure. Although a counterbore tool 44 is shown in Figures 5-8, it is to be understood that tool element 30 may be shaped so as to accommodate a facing tool, as shown by 30a in Figure 9, or to accommodate a bevelling tool, as shown by 30b in Figure 10. The tool element 30a in Figure 9 may be used to clamp a facing tool (not shown) to a second tool element 22a. Although a manual adjustment screw is not shown In Figure 9, the operative relationships between tool element 30a and tool element 22a are the same as that previously described. The clamping screws 40 perform precisely the same function as set forth in the previous embodiments. Figure 10 shows a tool element 30b to which may be attached a bevelling tool to form a bevel on the end of pipe 58. Quite obviously, the precise type of cutting tool does not alter the relationships between the first and second tool elements, and the locking cam member. The foregoing is provided for illustrative purposes only and should not be construed as in any way limiting this invention, the scope of which is defined solely by the appended claims.

Claims: WHAT IS CLAIMED IS; 1. A locking device for adjustably locking tool elements together including a first tool element defining a groove having at least a first side forming a female gib, a bottom and a second opposite side; and a second tool element having a portion slidably received in the groove; characterized by a locking cam member mounted in the second tool element so as to rotate about an axis extending generally parallel to the groove, the cam member defining both a clamping surface and at least one force receiving surface; and, at least one force exerting means attached to the second tool element and bearing against the at least one force receiving surface, whereby the cam member may be rotated such that the clamping surface contacts the female gib to lock the first and second tool elements together. 2. The locking device according to claim 1 characterized In that the locking cam member has a generally cylindrical configuration and is mounted in the second tool element so as to rotate about a longitudinal axis. 3. The locking device according to claim 2 characterized in that the clamping surface extends substantially radially from the longitudinal axis. 4. The locking device according to claim 3 characterized in that the clamping surface extends substantially the length of the locking cam member. 5. The locking device according to claim 3 characterized in that the at least one force receiving surface extends substantially radially from the longitudinal axis. 6. The locking device according to claim 5 characterized in that the clamping surface and the force receiving surface define an included obtuse angle. 7. The locking device according to claim 6 characterized in that the included obtuse angle is approximately 150°. 8. The locking device according to claim 1 characterized in that the second side of the groove forms an angle of approximately 90° with respect to the bottom of the groove. 9. The locking device- according to claim 1 further characterized by a means for attaching a cutting tool to the second tool element. 10. The locking device according to claim 9 characterized by a second means for attaching the first tool element to a rotatable cutting head. 11. The locking device according to claim 10 characterized in that the locking cam member has a generally cylindrical configuration and is mounted in the second tool element so as to rotate about a longitudinal axis. 12. The locking device according to claim 11 characterized in that the clamping surface extends substantially radially from the longitudinal axis. 13. The locking device according to claim 12 characterized in that the clamping surface extends substantially the length of the locking cam member. 14. The locking device according to claim 13 characterized in that the at least one force receiving surface extends substantially radially from the longitudinal axis. 15. The locking device according to claim 14 characterized in that the clamping surface and the force receiving surface define an include obtuse angle. 16. The locking device according to claim 15 characterized in that the included obtuse angle Is approximately 150°. 17. The locking device according to claim 16 characterized in that the second side of the groove forms an angle of approximately 90° with respect to the bottom of the groove.

Inventors: SCHUSTER RANDALL, VANDERPOL JERALD, SCHUSTER, RANDALL, VANDERPOL, JERALD
Applicants: TRI TOOL INC, TRI TOOL INC.
Application year: 1987
Main classification: F16B2
IPC codes: B23B29, B23D35, B23Q1, F16B2, F16B3, F16C29