Clamp

The present invention is directed to a clamp for firmly holding and securing a workpiece, or for use as a welder's ground clamp. Clamps are used in multifarious environments, such as for holding wooden furniture parts together for adhesive bonding, for holding metal parts together during the welding process, and the like. The clamp of the invention is in that class defined as spring clamps which provide a pair of clamping or holding jaws, one of which is pivoted to the other and urged toward the other jaw by a spring to secure the workpiece thereat in sandwich-like fashion. These prior art clamps, however, are not easily and readily adaptable to workpieces that vary greatly in size, whereby each clamp is expressly and specifically suitable for only a narrow range of sizes of workpieces. For larger-sized workpieces, larger spring clamps must be used, that cannot accomodate smaller-sized workpieces.

It is, therefore, the primary objective of the present invention to provide a spring clamp having a pair of clamping jaws which will readily and easily accomodate a large range of sizes of workpieces.

It is another objective of the present invention to provide such a spring clamp that will accomodate such a large range of sizes of workpieces such that such accomodation is continuous in that any sized workpiece within the size range may be accomodated, without any "blind" areas extant.

It is another objective of the present invention to provide such a spring clamp that may be used for holding and clamping any type of workpiece.

Toward these and other ends, the spring clamp of the present invention includes a lower clamping member at one end of which is mounted a rubber or soft pad element which actually grips a portion of a workpiece to be clamped, and an upper clamping member which incorporates an adjustable and removable L-shaped bracket having at one end another rubber or soft padded element for gripping an opposite portion of a workpiece. Each of the two clamping members is also provided with a rear handle element which are pivotally coupled together and are biased about the pivot axis by a spring provided between the two handle elements. The upper clamping member has a slide housing for slidingly mounting the L-shaped clamping bracket, which slide housing is integrally affixed to the end of the upper handle element and extends perpendicularly thereto. The slide housing extends directly adjacent to the upper surface of the lower clamping jaw when the two clamping members do not clamp a workpiece therebetween. The slide housing has an interior slideway in which slides one leg portion of the L-shaped bracket member. The slideway is open-sided at the portion thereof facing forwardly toward the upper rubber padded element, so that the other leg portion of the L-shaped bracket may project and extend outwardly therethrough. An indented or smaller-diameter rim portion of the other leg portion cooperates and receives nestled therein a pair of oppositely disposed retaining flanges projecting from the inner forward edge surfaces of the slide housing, so as to prevent the removal or falling out of the L-shaped bracket from the slide housing in the forward direction, through the open sided front surface thereof, while still permitting the entire L-shaped bracket to be removed by sliding it upwardly and out of the open top of the slide housing. The L-shaped bracket is positionable within the slide housing in two distinct manners: The first where the other leg portion, which has the upper rubber padded element affixed thereto at its forward, distal end, lies closer to the lower clamping member than the one leg portion of the L-shaped bracket contained within the slideway; and the second where the other leg portion lies farther away from the lower clamping member than the one leg portion, whereby conversion from the first to the second state automatically and relatively instantaneously converts the clamp from one state to clamp a relatively small-sized and narrow workpiece, to one that is able to accomodate a relatively much larger-sized and broader workpiece. A thumb screw secures the L-shaped bracket in any one of its many positions, whether in the first or second state thereof. The slideway has a length greater than the length of the one leg portion of the L-shaped bracket to ensure there are no "blind" spots where a particular thickness or size of workpiece could not be accomodated by the clamp of the invention, thus ensuring that a continuous range of sizes of workpieces may be accomodated within the range of sizes suitable to the particular clamp of the invention.

In anther embodiment of the invention, having special use as a welder's ground clamp, the lower clamping jaw is U-shaped for receiving therein a U-shaped gripping member that is used for gripping a lower portion of a pipe, or the like. The gripping member is adjustably positionable in the lower clamping jaw by a longitudinal channel formed in the base of the gripping member in cooperation with a screw passing through the base of the clamping jaw and channel, the screw being held in place at a desired portion of the channel by a wing nut. The lower handle portion of the clamp is also provided with a hole and screw therefor for connecting the end of a ground wire from a welder's generator supplying power to the weld gun, the clamp of the present invention being made of metal to provide such a ground connection. The base of the lower clamping jaw also is formed with a rectilinear-shaped through-opening in order to allow for the passage through the lower clamping jaw of part of the first leg portion of the L-shaped bracket, when the L-shaped bracket is extra-long, thereby allowing for even greater thicknesses of workpieces to be accomodated and clamped.

The invention will be more readily understood with reference to the accompanying drawing, wherein:

FIG. 1 is an isometric view of the first embodiment of the clamp of the invention in its first state thereof;

FIG. 2 is a side elevation view of the clamp of FIG. 1 in the second state thereof;

FIG. 3 is a cross-sectional view taken along line 3--3 of FIG. 2;

FIG. 4 is an isometric view of the second embodiment of the clamp of the invention;

FIG. 5 is a side elevation view thereof;

FIG. 6A is a perspective view of the U-shaped gripping member of the lower clamping jaw of the clamp of FIG. 4; and

FIG. 6B is an assembly view, in perspective, showing the parts for securing the U-shaped gripping member to the U-shaped lower clamping jaw.

Referring now to the drawings in greater detail, the spring clamp of the invention is indicated generally by reference numeral 10. The clamp 10 has a first, lower clamping jaw 12 which is integrally connected with a first, lower handle element or portion 14 extending rearwardly from the rear surface of the lower jaw 12. A second, upper handle element or portion 16 is provided and extends parallel to and is coextensive with the lower handle element 14 when in its rest position. The two handle elements are pivotally connected together by a pivot shaft 15 as seen in FIGS. 1 and 2, and are urged away from each other by a spring 17 mounted between the two handle elements. The second, upper handle element 16 is integrally connected, at its forward-most surface, to a vertically-oriented slide-housing 20 which in the preferred embodiment is a hollow tube having a rectilinear-shaped cross section. The slide-housing 20 has an open end 20' and a lower end 20", with the integral connection between the rear surface of the handle element 16 and the slide-housing being at the rear surface of the slide-housing at an intermediate portion thereof that is closer to the end 20" than the end 20'. In the normal, rest state of the clamp 10, the lower end 20" abuts against the upper surface of the lower clamp jaw 12, so that the alignment of the clamp takes place. The interior of the slide-housing 20 constitutes a slideway for slidingly receiving a first vertical leg portion 30 of an L-shaped bracket element 32. The leg portion 30 is also generally of rectilinear-shaped cross section for mating and sliding movement in the slideway of the housing 20. The first leg portion 30 has a free or unconnected upper end 30' and a lower end 30". The L-shaped bracket 32 also has a second horizontal leg portion 34 which constitutes the second clamping jaw. The second leg portion 34 extends parallel to the lower clamping jaw 12 when the clamp is in its rest or normal state, and is substantially coextensive therewith. The second leg portion 34 projects perpendicularly from the lower end 30" of the first leg portion, as seen in FIG. 2, and is formed integrally therewith.

The L-shaped bracket 32 may take on two separate states with respect to the slide-housing 20. The first state thereof is shown in FIG. 1, where the second leg portion 34 lies closer to the lower clamping jaw 12 than the free end 30' of the first leg portion 30. The second state thereof is shown in FIG. 2, where the second leg portion 34 lies farther away from the lower clamping jaw 12. In the first state, the connected or lower end 30" of the first leg portion is inserted first into the slideway of the slide-housing 20 through the open end 20' thereof, while in the second state thereof, the upper or free end 30' is inserted first into the slideway through the open end 20'. In the first state shown in FIG. 1, a workpiece 38 of relatively narrow thickness may be clamped between the lower clamping jaw 12 and the upper one 34. When it is desired to clamp therebetween a workpiece of much greater relative thickness, such is easily and readily accomplished by removing the L-shaped bracket and inserting the free end 30' into the open end 20' first to position the L-shaped bracket in its second state shown in FIG. 2, so that the much larger relative thickness may be readily accomodated, with only fine tuning of the upper jaw 34 being necessary thereafter. Whether in the first or second state, a thumb screw 50 having a threaded shank passing through an appropriately-provided hole in the rear surface of the slide-housing retains the L-shaped bracket in the desired position in the slideway, the fine-tuning above-stated requiring only small vertical adjustment of the first leg portion and its retention by the thumb screw.

Each of the ends of the lower clamping jaw 12 and upper clamping jaw or second leg portion 34 is provided with a rubber or soft clamping pad 54, 56, respectively, between which the workpiece is actually gripped and clamped. Preferably, each pad 54, 56 has a slightly greater size than the jaws themselves so that only the pads contact the workpiece.

The second leg portion projects outwardly and forwardly from the lower or connected end of the first leg portion and protrudes through the housing 20 via the opened forward portion thereof, and is prevented from escaping from the slideway in the forward direction by means of a pair of vertically-oriented, oppositely-disposed recesses or grooves 62, 64 that extend the entire height or thickness of the second leg portion, which recesses receive therein, respectively, a pair of mutually-facing flanges or beads 60, 62 formed along the inner surface of the side walls 21, 23, respectively, of the housing 20. Each bead or flange extends from its respective side wall at the forward edge thereof, as clearly shown in FIG. 3. The recesses 64, 66 define a reduced-diameter portion of the second leg portion adjacent its end connected to the end 30" of the second leg portion.

When using the clamp 10, for a relatively thin or narrow workpiece, the L-shaped clamp is positioned as shown in FIG. 1, while for a relatively thicker or broader workpiece, the L-shaped bracket is positioned as shown in FIG. 2. This allows for quick and facile adaptation of the clamp to two workpieces of considerable difference in size, without needing to pass through all the continuous intermediate stages necessary in prior art clamps.

The L-shaped bracket is preferably made of mild strength aluminum so that the point of the threaded shank of the thumb screw 50 may bite into the surface of the first leg portion and prevent slippage. The length of the slideway is greater than the length of the first leg portion so that all intermediate positions of the clamp may be realized, without any "blind spots" present. The size and length of the L-shaped bracket's portions will vary depending upon the end use, as will the slideway and lower clamping jaw.

It is possible to provide a different slide arrangement, where the female receiving portions or recesses 64, 66, are provided in the housing 20, and the male parts on the second leg portion 34, as in the mortise and tenon type connection or dovetail connection.

A modification of the clamp 10 is shown in FIG. 4, and allows for the accomodation of extra-long first leg portions 130 of the L-shaped bracket 132 when such is positioned in the second state thereof shown in FIG. 2. Such accomodation is achieved via a rectilinear-shaped through-opening or cutout 71 formed in the case or lower wall of the lower clamping jaw 112. This through-opening is in substantial alignment with the hollow interior of the slide-housing 120 when the handle means 114,116 are in their normal, spaced-apart state when a workpiece is being clamped. The free end 130' of the L-shaped bracket in the second state thereof may project through the through-opening 71 as shown in FIG. 4 in order to accomodate any size thickness of workpiece, offering a much greater range of workpiece thicknesses that may be accomodated as compared with the clamp 10. The opening 71 preferably has a length as taken in the direction parallel to the length of the clamping jaw 112 that is greater than the thickness of the first leg portion 130, which thickness is taken in the same direction as the length of the opening 71, whereby, when the two handle elements 114 and 116 are pivoted about the pivot pin 115, clearance is provided for the portion of the first leg portion situated within the through-opening, in the manner best seen in FIG. 5. Of course, the L-shaped bracket may also be used in the first state thereof, in the manner shown in FIG. 1, with the free end 130' projecting upwardly and out from the upper end of the slide housing 120.

Referring now to FIGS. 5-6, there is shown a second embodiment of the clamp of the invention, indicated generally by reference numeral 10". The clamp 10" may be used in the same manner as the clamp 10, but has additional use as a welder's clamp. When welders use a weld gun of a welding apparatus for welding pipes, hollow tubes, and the like, the ground wire of the welding apparatus may be grounded, which is presently done by first welding an angle iron, or the like, to the pipe itself if the end of the pipe is not accessible. Then the ground wire clip is secured to this angle iron to achieved the ground. This is a timely and extremely inconvenient process. The clamp 10" obviates the need for using and welding an angle iron to the pipe proper and itself clamps between its upper and lower clamping jaws the pipe section at which it is located and at which the grounding of the welding apparatus is to be carried out.

The clamp 10" also includes a lower, U-shaped clamping jaw 212 with a rectilinear-shaped opening 271 through which passes a part of the first leg portion 130 of a L-shaped bracket 132, as described previously for the clamp 10. The lower clamping jaw 212 is provided with a U-shaped, alligator gripping member 238 best seen in FIG. 6A. The gripping member 238 has a base wall portion 240 in which is formed a longitudinally-extending channel 242, and a pair of upstanding side walls 244, 246 projecting from the side edge surfaces of the base wall portion 240. The upper edge surface of each side wall is provided with serrations 250 to aid in the gripping of a pipe, or the like, when the clamp 10" is used as a welder's ground clamp. The gripping member 238 is adjustably positionable in the lower clamping jaw 212 in order to accomodate different sizes of pipes or the like and different lengths of second leg portions 134 with the concomitant different projection of the upper gripping surface pad 256, which in this embodiment is preferably more elongated than the pads 56 or 156 for better gripping a curved surface of a pipe, or the like. The alligator clamping member 238 is secured at a desired position in the lower, U-shaped clamping jaw 212 via a screw or carriage bolt 271 and associated wing nut 273, the shank of the screw passing through a hole formed in the lower clamping jaw adjacent the front end thereof, and also through the channel 242, as best seen in FIG. 5. By simply loosening the wing nut and moving the alligator gripping member relative to the lower clamping member, with the screw 271 remaining stationary as the channel 242 moves therepast, it is possible to either move the alligator gripping member closer or farther away from the slide-housing 220. The carriage bolt 271 has an enlarged, conventional head portion 275 by which it is turned, and also includes a lower, secondary rectilinear-shaped head portion or built-in nut portion 277 which fits snugly inside the channel 242, so that no wrench is needed to tighten the bolt, since the built-in nut remains within the channel 242 and prevents rotation of the screw as the wind nut 273 is rotated to tighten the connection.

The clamp 10" also includes a ground-wire receptacle or hole which threadingly receives therein a ground-screw 281 for securing and grounding a ground-wire lead clip 283. The ground wire clip 283 is part of a ground wire of a conventional welding apparatus having a welding gun for welding pipes, or the like. Thus, when a welder wishes to weld a pipe, or the like, and when the end of the pipe is not accessible for securing the ground-wire clip thereto, the clamp 10" is used instead, the clamp 10" being made of suitable metal or alloy to effect the grounding, which obviates the need of welding an angle iron to the pipe being welded, which has hitherto been necessary.

While a specific embodiment of the invention has been shown and described, it is to be understood that numerous changes and modifications maay be made therein without departing from the scope, spirit and intent thereof as set forth in the appended claim.