Slide Bar Clamp and Straight Edge

The present invention is directed to a clamping mechanism that doubles as a straight edge.

Clamps, vises, and straight edges are commonly used hand tools. Vises and clamps are used to hold a work piece in place. While a workpiece is clamped, other operations may be performed on the piece, such as sawing, routing, or drilling. Also, clamps may be used to hold the workpieces together that have been glued to allow the adhesive to set. If an operation needs to be performed along a straight edge, a solid straight edge may be clamped at either end to a work piece. This generally involves the use of two clamps along with the straight edge.

The hand tool of the present invention advantageously performs several functions. It can be used as a mountable straight edge. It can be used as a simple bar clamp. The invention may further be used by mounting two of the clamps back-to-back to serve as a double-sided clamp which permits clamping a work piece to one of the clamps and using the clamp on the other side to attach the double-sided clamp to a fixed base or bench.

The apparatus includes an elongated base with a straight longitudinally running surface that can operate as a straight edge. The base includes a hollow channel through which a solid rod is suspended. A fixed clamp surface perpendicular to the rod is attached to one end of the elongated base. A moveable lock and clamp structure is mounted in the hollow channel so as to be longitudinally moveable along the rod. The lock and clamp structure includes a moveable clamp surface facing the fixed clamp surface. The lock on the moveable clamp structure can engage the solid rod to prevent the lock and clamp structure from moving in a direction away from the fixed clamp surface.

The lock of the invention includes a plurality of lock plates, each with a hole therethrough. The lock plates are mounted with the solid rod through their holes. A spring surrounding the rod and inserted within the lock and clamp housing pushes against the lock plates. A handle is rotatably mounted on the lock and clamp housing. The handle includes a narrow portion against which the lock plates lean in a sufficiently perpendicular position to the rod so that the housing can be moved longitudinally back and forth along the rod. The handle includes a cam portion which, when the handle is rotated into the locked position, causes the lock plates to tilt with respect to the rod, thereby preventing the lock and clamp housing from moving in a direction away from the fixed clamp surface. As the handle is rotated from the open position to the locked position, the housing is urged in a direction towards the fixed clamp structure to better secure the workpiece between the two clamp surfaces.

The elongated base has a flat bottom surface. Screw holes in the bottom surface may be used to mount the clamp on a flat surface. Moreover, the clamp may be mounted to the back of another identical clamp. Thus a double-sided clamp can be formed with two flat bottomed clamps of the present invention. The lock and clamp housing in the clamp of the present invention can be moved along the base with one hand that can also be used to operate the lock. Thus, the slide bar clamp of the present invention allows for simple one-handed operation of the lock and clamp. Other objects and advantages of the present invention will become apparent during the following description of the presently preferred embodiments of the invention taken in conjunction with the drawings.

FIG. 1 is a perspective view of the slide bar clamp and straight edge of the present invention.

FIG. 2 is an exploded view of the clamp and straight edge of FIG. 1.

FIG. 3 is a plan view of the clamp and straight edge of FIG. 1 with the lock structure in the open position.

FIG. 4 is a plan view of the clamp and straight edge of FIG. 1 with the lock structure in the locked position.

FIG. 5 is a perspective view of two slide bar clamps of the present invention mounted back-to-back to form a double-sided clamp.

The slide bar clamp and straight edge of the present invention shall now be described in greater detail with reference to the drawings. The clamp is formed on an elongated base 1. An elongated hollow channel is formed in the top of the base 1. A bottom surface of the base 1 is flat. Extending up from the two opposed longitudinal edges of the bottom flat surface are straight surfaces 40. The straight surfaces 40 may serve as a straight edge. An overhang 11 extends inward from each of the straight surfaces 40 to provide a track over the hollow channel on the top of the base. The moveable lock and clamp structure 2 is mounted on the channel. The moveable lock and clamp structure includes a clamp surface 23 which faces toward a fixed clamp surface 3 attached to an end of the base 1. A rod 4 is suspended within the channel of the base. The moveable lock and clamp structure 2 is mounted on the rod 4 for longitudinal movement back and forth along the channel. A lock handle 6 is rotatably mounted on the lock and clamp housing. The lock handle 6 is secured at its pivot point by a pivot screw 7. The handle 6 can be moved between an open position in which the lock and clamp housing can be moved freely back and forth along the rod 4 and a locked position in which the lock and clamp housing is prevented from moving in a direction away from the fixed clamp surface 3. In the locked position, a workpiece can be held securely in position between the fixed clamp surface 3 and the moveable clamp surface 23.

A more detailed understanding of the slide bar clamp of the present invention may be had with further reference to FIG. 2. At each opposite end of the channel in the base 1 there is mounted an endplate 30. Each endplate 30 includes an endwall with a hole 31 therein through which the rod 4 is inserted. The rod 4 is provided with a thread 41 at each end thereof. A nut 10 may be used at each end of the rod 4 to hold the apparatus together. The endplates are designed so as to fit within an end of the channel. By securely attaching a nut 10 to both ends of the rod 4, both endwalls are held securely against the base 1 to complete the clamp apparatus. The endplates are each provided with nubs 33 which snugly fit beneath the overhang 11 in the base 1. The nubs 33 prevent the endplates from sliding off the channel while the rod 4 and nut 10 hold the endplates against the ends of the base 1.

Each of the endplates 30 is provided with a bottom surface which aligns flush with the bottom surface of the base 1. Thus, the bottom surface of the endplates forms an extension of the base 1. Each of the bottom surfaces of the endplates is provided with two screw holes 35. The screw holes 35 may also be used to attach the clamp to an adjacent flat surface, such as a bench or wood block. The screw holes 35 may be used as described later with respect to FIG. 5 to attach a second clamp to the first clamp, thereby forming a double-sided clamp.

The fixed clamp surface 3 is formed as an integral part of one of the endplates 30. The fixed clamp surface is oriented perpendicular to the rod 4 and the straight surface 40. The moveable clamp surface 23 on the movable lock and clamp structure faces the fixed clamp surface 3. The moveable lock and clamp structure is formed in a housing 2. A plurality of lock plates 9 are inserted within the housing. Each lock plate 9 includes a hole 91 through which the rod 4 is inserted. The lock plates 9 are arranged face-to-face one against the other within the housing. A spring 8 also mounted about the rod 4 is inserted between a housing wall and the lock plates 9. The spring 8 urges the lock plates in the direction towards the fixed clamp surface 3. The holes 91 in the lock plates 9 are in the lower portion of the lock plates. Against the upper portion of the lock plates 9 is the handle 6. The handle 6 rotates about a pivot 52. A screw 7 attaches the handle 6 to the pivot 52. The screw 7 may be removed to allow the handle 6 to be flipped over to switch the handle between left and right handed operation. The screw 7 is then replaced to secure the handle on the pivot 52. Pivot 52 is located atop a stump 5. The stump 5 has a hole 51 therethrough through which the rod 4 extends. The stump 5 fits down into a well 22 in the housing 2 of the lock and clamp structure. The housing 2 includes a hole 21 therethrough for insertion of the rod 4. The housing 2 is provided with nubs 24 above and below the overhang 11. Thus, the housing can slide back and forth along the channel with the nubs 24 holding the housing on track within the overhangs 11.

The handle 6 assumes two basic positions. In FIG. 3, the open position is shown. A narrowed portion 62 of the handle is narrowed in that there is a relatively small distance between the pivot 52 and the edge of the handle. In the open position, the lock plates 9 lean against the narrowed portion 62 of the handle. The spring 8 pushes the lock plates 9 against the narrowed portion. In this position, the lock plates 9 are sufficiently perpendicular to the rod 4 such that the lock and clamp structure can be freely moved back and forth through the channel along the rod 4. As the handle 6 is moved from the open position of FIG. 3 into the locked position shown in FIG. 4, a transition portion 63 of the handle slides against the lock plates 9. The transition portion gradually increases the distance between the pivot point 52 and the edge of the handle pushing against the lock plates 9. This causes the lock plates to tilt such that the edges of the holes 91 of the lock plates grab against the rod 4 such that the lock plates cannot be moved in the direction away from the fixed jaw surface 3. As the distance between the pivot point 52 and the edge of the handle 6 continues to increase, the housing 2 of the clamp and lock structure is moved towards the fixed jaw clamp surface 3. The clamp surfaces are thus forced together, more securely holding a workpiece between them. In the final locked position shown in FIG. 4, the cam portion 64 of the handle is leaning against the lock plates 9. The lock plates are thus tilted with respect to the rod 4. In this position the inner edges of the holes 91 in the lock plates prevent movement of the lock and clamp structure 2 in a direction away from the fixed clamp surface 3.

In accordance with the present invention, it is a simple matter to move the lock and clamp structure with one hand into the desired position with respect to a workpiece and then use a finger to engage the locking handle. Thus, locking a workpiece to the slide bar clamp can be a simple one-handed operation. With the slide bar clamp attached to a workpiece, the straight surfaces 40 can be used as a straight edge. The clamp holds the edges securely in position. Other operations such as drilling, routing, sawing or sanding may then be performed using the secured straight edge surface 40 as a guide. For example, a router may be operated along the straight edge to rout an area delineated by the straight edge. The straight edge is advantageously held firmly in position on the workpiece by the clamp surfaces of the slide bar clamp and straight edge. Additional clamp are not required.

The details of the materials used in the presently preferred embodiment shall now be described. The presently preferred base 1 is formed from extruded aluminum. The rod 4 is a heat-treated steel rod. The endplates 30 and the housing 2 are all formed from molded nylon. The clamp surfaces may be provided with an array of teeth to provide additional gripping power. The spring 8 is formed from music wire. The lock plates 9 are formed from heat-treated steel. These materials are merely those of the presently preferred embodiment. Any number of other materials may be substituted which can equally perform the functions of the present invention.

Referring now to FIG. 5, the slide bar clamp of the present invention is shown in a back-to-back configuration so as to form a double-sided clamp. The double-sided clamp is formed by attaching two of the slide bar clamps of FIG. 1 together with their bottom faces adjacent one another. The screw holes 35 in the endplates of each of the slide bar clamps are used to fasten the two clamps together with nuts and bolts. The resulting double-sided clamp has four clamping surfaces. Each side has a fixed clamp surface and a moveable lock and clamp structure. While one side of the clamp may be used to attach the double-sided clamp to a saw horse, for instance, the other side of the clamp may be used to attach the workpiece.

Of course, it should be understood that various changes and modifications to the preferred embodiments described above will be apparent to those skilled in the art. For example, alternative clamping mechanisms may be used on the lock and clamp structure of the slide bar clamp and straight edge. Also, the double-sided clamp may be made an integral structure rather than through the attachment of two individual slide bar clamps. These and other changes can be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be covered by the following claims.