Guide Clamp

The present invention relates to tool guiding and marking devices and more particularly to guides and markers which are clamped to a workpiece. As such, the invention will be hereinafter called a "guide clamp," functioning both as a guide and a clamp.

The present invention is a development from and an improvement over the "guide clamp" disclosed in my application, Ser. No. 326,840, filed Dec. 3, 1981, and which has matured into U.S. Pat. No. 4,394,800, dated July 26, 1983, and which is embodied herein in its entirety by reference. The prior guide clamp and the guide clamp disclosed herein are similar in appearance and may be used in a similar manner. However, their internal features differ in significant aspects to attain a more simple, economical and versatile structure in a guide clamp as herein disclosed.

Guide clamps are not new and the patent to William J. Fortune, U.S. Pat. No. 3,287,808, is exemplary of the prior art. The basic features of a guide clamp include a guide bar having a pair of gripping jaws outstanding from one edge of the bar to clamp onto a workpiece such as a board. One jaw, the clamping jaw, is at one end of the bar. The other jaw, the shifting jaw, may be positioned along the reach of the bar to bring the jaws against the edges of the workpiece and the clamping jaw will then secure the guide clamp onto the workpiece. The guide clamp may be used for various purposes such as for clamping parts together, marking or providing an abutment for a power hand saw which is held against the guide clamp as it makes a cut across the workpiece.

The present invention combines these basic features into a neatly arranged, compact unit wherein the components of the clamping jaw and the shifting jaw which connect with the bar are carried within a channel-shaped bar completely out of the way and with only the jaw face abutments and finger gripping wings at the shifting jaw projecting below the bar.

It follows that the objects of the invention are to provide a novel and improved guide clamp which: (a) can be used to hold and guide power hand tools in proper positions and in precise alignment as they are moved across a workpiece; (b) can be used to hold attachments and special tools for precision woodworking operations; (c) can be quickly and easily mounted upon a workpiece and secured thereto by simply pushing a lever; (d) can be attached to a workpiece with no portion of the jaws or other parts of the clamp projecting below the workpiece to permit the workpiece to lie flat upon a table with the guide clamp in place; (e) has an adjustable shifting jaw which is easily moved along the reach of the reach of the guide bar and locked in place on the guide bar at any selected position; (f) provides for an improved and simplified locking mechanism on the shifting jaw which is completely within the embrace of a channel shaped bar in an out-of-the-way position; (g) is a lightweight unit useful as a clamp, guide and a base whereon other tools may be affixed; and (h) may be manufactured at low cost from extruded and molded low-cost materials as a neat-appearing, economical, rugged and durable unit.

With the foregoing and other objects in view, my invention comprises certain constructions, combinations and arrangements of parts and elements as hereinafter described, defined in the appended claims and illustrated, in preferred embodiments, in the accompanying drawings, in which:

FIG. 1 is an isometric view of the improved guide clamp mounted upon a board or a workpiece, for clamping or marking;

FIG. 2 is a transverse sectional elevational view of the guide clamp bar as taken from the indicated line 2--2 at FIG. 1 but on an enlarged scale;

FIG. 3 is a sectional view similar to FIG. 2 but showing an alternate construction of the bar;

FIG. 4 is a sectional view similar to FIG. 2 but showing another alternate construction of the bar;

FIG. 5 is a side elevational view of the guide clamp as taken from the indicated arrow 5 at FIG. 1 but on an enlarged scale and with portion broken away to conserve space;

FIG. 6 is a longitudinal sectional elevational view as taken from the indicated line 6--6 at FIG. 1 but on an enlarged scale and with portions broken away to conserve space;

FIG. 7 is a sectional plan view as taken from the indicated line 7--7 at FIG. 6 showing the components forming the clamp jaw;

FIG. 8 is an isometric exploded view of the clamp jaw components shown at FIG. 7;

FIG. 9 is a sectional plan view as taken from the indicated line 9--9 at FIG. 6, showing the components forming the shifting jaw;

FIG. 10 is an isometric exploded view of the shifting jaw components shown at FIG. 9;

FIG. 11 is a fragmentary portion of the shifting jaw components as shown at FIG. 9 but on an enlarged scale and illustrating the same as being locked to the guide clamp bar as for clamping to a workpiece;

FIG. 12 is a fragmentary portion of the shifting jaw components, similar to the showing at FIG. 11, but illustrating the same as being unlocked from the guide clamp bar for free shifting of the shifting jaw on the guide clamp bar;

FIG. 13 is a fragmentary portion of the guide clamp bar as taken from the indicated line 13--13 at FIG. 2 but on a greatly enlarged scale and illustrating an alternate construction to more effectively secure the shifting jaw onto the guide clamp bar; and

FIGS. 14 and 15 are fragmentary sectional details of a portion of an alternate construction of parts of the shifting jaw mounted on the guide clamp bar and wherein FIG. 14 is viewed from the indicated line 14--14 at FIG. 15 and FIG. 15 is viewed from the indicated line 15--15 at FIG. 14.

Referring more particularly to the drawing, the improved guide clamp G includes a straight, elongate bar B. A clamp jaw C is affixed to the head end of the bar and an opposing shifting jaw S is movable along the reach of the bar. An end cap E may be affixed to the rearward end of the bar. The clamp and shifting jaws S and C depend from the underside of the bar B to grip the opposite edges of a workpiece W such as a board. The jaws are spaced for gripping the workpiece by moving the shifting jaw S along the bar and the guide clamp G is then locked upon the workpiece W by depressing a lever L outstanding from the clamp jaw as illustrated at FIG. 6. It is to be noted that this guide clamp G may be of any length necessary to accommodate and fit upon any flat workpiece with which it will be used.

The bar B, illustrated in section at FIG. 2, is channel shaped with a top surface 20 constituting the web portion of the channel and with legs 21 depending from the edges of the top surface 20 constituting the flange portions of the channel. The cavity 22 between these legs 21 is constricted at its lower opening by an inturned lip 23 at the bottom of each leg. The upper portions of the clamp jaw C and the shifting jaw S and the end cap E fit into this cavity 22 as hereinafter described. This channel shaped bar B is a symmetrical unit to provide a neat appearance, and is manufactured as an extrusion of a high-strength aluminum alloy or similar metal of sufficient strength for the purpose at hand. The extrusion may be cut to selected lengths for economical manufacture of the bars so the only machining operations necessary will be squaring the ends 24 to better fit with the clamp jaw C and end cap E.

The bar B', illustrated in section at FIG. 3, has the same features as the bar B. The bar is channel shaped with a top surface 20', legs 21' to form a cavity 22' and with a constricted lower opening formed by inturned lips 23'. However, this bar B' is manufactured by bending and forming sheet metal such as steel plate. Such forming operations are conventional and need not be described. The purpose of such a construction is to reduce the cost of manufacture and provide a stronger and stiffer bar.

The Bar" is essentially the same as bar B and is also manufactured from an extrusion of selected metal. The top surface 20, the legs 21, the cavity 22 and the inturned lips 23 are the same as heretofore described. However, a slide slot 25 is provided alongside one or both legs 21 by a flange 26 upstanding from an outwardly projecting shoulder 27. Also, to hold a fixed attachment on the bar, a notched guideway 28 is located at the outer face of a leg near its top edge above the flange 25. The attachments used with this bar B" are described in my aforementioned copending application, Ser. No. 326,840, and need not be further described.

The clamp jaw C, shown at FIGS. 6, 7 and 8, is actuated by the lever L mounted in a block 30 at the end of the bar B. The lever L is formed as a flat arm 31 having an enlarged, cylindrical cam head 32 which fits in a socket in the block 30 and within the bar cavity 22. The cam head 32 has a passageway 33 through it and a flat face 34 normal to the surface of the arm 31. The block 30 is formed with spaced wall portions 35 which abut against the bar end 24. The wall portions 35 upstand from a floor section 36 at the undersurface of the bar. Spaced lugs 37, which snugly fit into the bar cavity 22, join with the wall portions 35 and floor 36. The cam head 32 is fitted between the lugs 37 and passageways 38 through the lugs 37 and through the legs 21 of the bar B register with the cam head passageway 33 to receive a pintle pin 39. The assembly is thus held in place and when the lever L is in the up position, as shown at FIG. 5, the end of the clamp jaw C abuts against the flat face 34 and against the block 30, but, when the lever L is depressed, as shown at FIG. 6, the cam head rotates to shift the clamp jaw C towards a workpiece to lock it into place.

The clamp jaw C is a comparatively stubby member having an upper support block 40 shaped to slidably fit in the bar cavity 22 and an abutment 41 below the block 40 which includes the jaw face 42. A neck 43 separates the support block 40 and the abutment 41 to receive the inturned lips 23 of the bar legs 21. An abutment wall 44 opposite the jaw face 42 is extended to the support block 40 to engage the lever head 32. The jaw face 42 is also extended to the support block 40 to carry a socket 45 where a reaction spring is mounted as will be described.

The clamp jaw C may be formed as a skeletal structure with pocket-like cavities in both the support block 40 and the abutment 41 in any suitable pattern such as illustrated. This cavity pattern saves material and facilitates forming a dimensionally stable component, especially when the clamp jaw C is molded from a selected, strong plastic material such as nylon. It is to be noted that nylon is one preferred material for the manufacture of the clamp jaw C, the lever L, the sliding jaw S and the end cap E, all with conventional injection molding operations.

When securing a workpiece in the guide clamp by depressing the lever L, the clamp jaw C moves towards and against the workpiece a short distance `d` as shown at FIG. 6. To release the guide clamp C from the workpiece W it is merely necessary to lift the lever L and in doing so the clamp jaw C is free to move back to its initial position, as against the block 30 as shown at FIG. 5. This mcvement is automatically accomplished by a reaction spring 46 which is mounted between the jaw face 42 and a holding block 47 fitted into the bar cavity 22 a short distance from the jaw face 42. The holding block 47 is provided with a socket 48 opposite to the jaw face socket 45 and the ends of the spring 46 are fitted into these sockets to hold it into place. The holding block 47 is secured in position in the cavity 22 by pins 49 driven into matching holes 50 through the block and in the legs 21 of the bar B, as shown in FIG. 7. The bias of the spring 46 keeps the clamp jaw C against the cam head 32 of the lever L at all times.

The shifting jaw S combines a jaw block 51, lock clips 52 and a release carrier 53 as shown at FIGS. 6, 9, 10, 11, and 12. The jaw block includes an H-shaped structure in the bar cavity 22 above the inturned lips 23 with a head wall 54 at the forward side of the jaw block 51, that is, the side facing the clamp jaw C. A transverse rear wall 55 at the opposite side of the jaw block 51 and a longitudinally disposed central wall 56 between the head and rear walls completes the H-form. A floor 57 between the bar lips 23 connects with the lower edges of the walls 54, 55 and 56 to form two side-by-side compartments in the bar cavity 22. A pair of spaced, opposing T-shaped guides 58 merge with, and extend below and rearwardly from the floor 57 to be embraced by the inner faces and under sides of the inturned lips 23 and provide opposing parallel guidewalls between which the release carrier is mounted as hereinafter described. A transverse abutment 59 is positioned below the forward end of the floor 57, and below the head wall 54, with its forward side forming the jaw face 60. The forward portions of the guides 58, below the floor 57, are widened to extend downwardly to merge with the abutment 59. The rearwardly extended portions of the guides 58 have undersurfaces 61 which are parallel with the inturned lips 23 thereabove to permit the guides to slide in a groove in the release carrier.

The lock clips 52 are flat rectangular plates of hard metal, with squared, sharp edges to grip the inner walls of the bar legs 21 and thereby lock the shifting jaw to the bar. A set or nest of three or four lock clips 52 is mounted in each side compartment formed by the walls 54, 55 and 56 above the floor 57. The inward end of each nest of clips 52 is carried on a pad 62 located at the corner formed by the central wall 56 and the forward head wall 54. Thence, the nest of clips extends outwardly and rearwardly therefrom at a suitable angle to reach to and engage the inner wall surface of the adjacent bar leg 21, as shown at FIGS. 9 and 11. When so engaged, with the opposing nests of lock clips 52 pushing against the wall 56 and against the opposing bar legs 21, the shifting jaw is tightly locked to the bar. The lock clips 52 may have an outer corner rounded as at 63, FIG. 10, to better fit the fillet formed at the corner between the under surface of top 20 and the inner surface of the leg 21 shown at FIG. 2. To complete the lock clips, a central slot 64 is provided in each lock clip 52 to receive a pull bolt 65 as hereinafter further described.

The outer end of each nest of clips 52 is adapted to shift rearwardly to move the clips out of engagement with the bar legs 21 and to the position shown at FIG. 12. So positioned the shifting jaw S may be moved back and forth along the bar B. The nests of lock clips 52 are normally, and resiliently, held in this disengaged position by the release carrier 53. The release carrier is shaped as a rectangular post topped by a forward transverse head 66 and a rearward transverse head 67. The heads are proportional to fit in the bar cavity 22 above the inturned lips 23. The sidewalls 68 of this post-shaped carrier lie between the guides 58 as heretofore mentioned. A pair of wings 69 outstand from opposite sides of the bottom of the post to facilitate gripping and shifting of the shifting jaw S. A slide slot 70 in the base of each wing 69 adjacent to the sidewall 68 receives the lower undersurface 61 of the guide 58 fitting against the sidewall.

A lip 71 cantilevers from the forward wall of the post forming the release carrier 53 to lie underneath the floor 57 and two spaced rods 72 upstand from this lip to extend through slots 73 in the floor 57. Each pull bolt 65 is formed with a tubular head 74 adapted to fit over a rod 72. The bolt shaft 75 of each pull bolt is extended through the slots 64 of its nest of lock clips 52 and secured thereto by a lock nut 76 with a free fit. These components are so proportioned that movement of the release carrier 53 towards the jaw block 51 engages the nested lock clips 52 with the walls of legs 21, FIG. 11, and movement of the release carrier away from the jaw block 52 releases the nested lock clips from the walls of the legs 21, FIG. 12. To keep the release carrier in a releasing position except when the jaw block engages a workpiece, a spring 77 is mounted between the jaw block 51 and carrier 53 in respective sockets 78 and 79.

The end cap E at the end of the bar opposite to the clamp jaw C need not be described since it is cosmetic and does not contribute to the operation of the guide clamp. It may assume any suitable form which will fit upon the bar and close the cavity 22 at the end of the bar.

A number of alternates and variations to the features herein described are possible to devise and develop and such need not be described herein. The structure shown at FIG. 13, however, provides for a modification of the bar B which is desired where the guide clamp is to grip a workpiece W with considerable tightness. When the bar B is formed of extruded aluminum and the lock clips 52 of the shifting jaw S are of tempered steel with sharp edges, it is possible that the lock clips will bite into the inner walls of the bar legs 21 deeper than can be tolerated. To avoid such a result, modified bar legs 21a are formed with serrations 80 spaced such that each lock clip 52 will seat upon a serration step as illustrated. Such serrations are easily formed in the bar after it is extruded by pulling a cog-wheel tool through the channel cavity 22. With such serrations the locking of the shifting jaw S is positive in all respects.

FIGS. 14 and 15 illustrate a modified mode of mounting lock clips 52a of the shifting jaw S in the channel cavity 22 by placing the lock clips 52a upright to engage the underside of the top 20 of the bar B. The jaw block 51a is modified by extending the floor 57a about and above the inturned lip 23 of the bar B. A pad 62a on the floor 57a holds a nest of lock clips 52a to incline upwardly and rearwardly to the underside of top 20. A pull bolt 65a extends horizontally through a passageway 81 in the rear wall 55 to connect with the forward head 66 of the release carrier 53. The pull bolt 65a is shaped to extend through slots 64a of the lock clips 52a to hold these lock clips together and to shift them against and away from the undersurface of the top 20. The other elements of this modified shifting jaw S' are essentially the same as hereinbefore described.

The operation of the improved guide clamp G is apparent from the foregoing description. The guide clamp G is placed upon a workpiece with the clamp jaw at an edge of the workpiece. The shifting jaw is then moved to the opposite edge of the workpiece with sufficient pressure against the wings 69 to push the jaw face 60 against the workpiece and overcome the bias of spring 77. This movement brings the lock clips 52 against the legs 21 to initiate locking of the shifting jaw onto the bar B. Depression of the lever L then moves the clamp jaw against the workpiece to securely lock the guide clamp G onto the workpiece.

I have now described my invention in considerable detail. It is obvious, however, that others skilled in the art can devise and build alternate and equivalent constructions which are within the spirit and scope of my invention. Thus, my protection should be limited, not by the constructions illustrated and described, but only by the proper scope of the appended claims.