Adjustable Gripping and Locking Tool

1. Field of the Invention

This invention relates to hand tools in general, and more specifically to a gripping and locking plier or wrench of the vise-grip class.

2. Related Art

This invention is an improvement over the hand tools contained in a number of prior patents, the most predominant and successful being that of Petersen, U.S. Pat. No. 2,280,005, issued Apr. 14, 1942. This tool was called a vise-grip and has been on the market for over 50 years without any serious challenge as to its manner of construction and operation.

The vise-grip tool and various copies of it have several disadvantages, however, and many attempts have been made to eliminate these disadvantages but to date there has been little, if any, success in doing so.

The most serious problem has to do with the adjustment of the jaws to a work piece prior to locking. In order to understand the problem, one must first understand how the jaws are adjusted in the original Petersen tool, which is still used today. The adjustment mechanism includes a manually operated threaded screw that is turned clockwise to open the jaws wider and counter-clockwise to narrow the jaw opening. This screw extends axially inside an elongated hollow handle and has a knurled head protruding from the end of the handle, and the other end of the screw contacting one end of a fulcrum bar which is attached at its opposite end to a pivotable locking lever, or pivoting handle as it will be called herein for purposes of simplicity, and which in turn is attached to an adjustable jaw. The adjustable jaw pivots toward or away from a fixed jaw on the fixed handle. To adjust the tool to a work object, it is held in one hand while the other hand turns the screw head, thereby pivoting the adjustable jaw in a scissor-like fashion either toward or away from the fixed jaw. In order for the jaws to be locked on a work piece, the position of the adjustable jaw is very limited and critical to the locking operation as both jaws cannot be put into contact with the work piece at the same time and still be able to lock them. If such contact is made, they are too close for the lock to be activated; and by the same token, if the adjustable jaw is too far away from the work piece, the jaws still cannot be locked on the work. Therein lies the problem. In order to obtain this critical adjustment of the pivotable jaw, the adjusting screw must usually be adjusted several times before the proper adjustment can be achieved. This fine adjustment is required to lock the jaws every time a different sized work piece is involved.

A second disadvantage is that both hands must be used in order to adjust the tool so that it may be locked on a work piece as described above.

A third disadvantage is that both hands must also be used to release the jaws from a locked position, and if the lock is very tight, the release trigger becomes very difficult to operate. When it finally is activated, the handles will fly apart with considerable force and with possible injury to the operator.

A fourth disadvantage is that the adjustable jaw pivots in an arc and "scissors" as is mentioned above instead of moving in a linear direction. As a result, there is only one point at each adjusted position where the jaws are actually parallel to effect the best grip on a work piece, and it also limits the range of the jaw gap.

Still another disadvantage is the fact that when a vise-grip type tool is adjusted to where the adjustable jaw is at or near its most wide open point, the fixed handle and pivoting handle are so far apart as to be unreachable for the span of an average hand, again requiring the second hand to assist in bringing them together.

Accordingly, several objects and advantages of my invention are:

(1) To provide an adjustable gripping and locking tool wherein the jaws can be adjusted quickly and easily directly against a work piece, with such adjustment producing a light or heavy grip at the choice of the operator, the adjustment being accomplished in just one move of the thumb of the hand holding the tool;

(2) to provide such a tool as in (1) above that has constantly parallel jaws that do not "scissor" during the adjustment operation;

(3) to provide an adjustable locking tool wherein the adjusting, locking and unlocking operations can be done with just one hand; and

(4) To provide an adjusting and locking tool where the spread of the handles at their most wide open position is restricted to the normal span of an average hand for gripping purposes.

Additional objects and advantages of my invention will become apparent from a consideration of the drawings and ensuing description of it, wherein a number of preferred embodiments are presented. It will be understood that the embodiments presented are for illustration purposes only and the invention is not necessarily limited to such, but may be adapted and used for any purpose for which it is found to be suitable.

FIG. 1 is an elevational view as seen from one side of the tool.

FIG. 2 shows a fragment, partly in section, of the outer end of the elongated handle as viewed from the bottom side.

FIG. 3 is the same fragment shown in FIG. 2, partly in section, as seen from one side.

FIG. 4 is an elevation of the tool as shown in FIG. 1 rotated 90 degrees clockwise.

FIG. 5 is a plan view of the tool shown in FIG. 1.

FIG. 6 is a plan view of an alternate adjustable jaw construction.

FIG. 7 is an elevation of a second alternate adjustable jaw configuration.

Referring to the corresponding numbers on the attached drawings, my invention is composed of the following:

FIGS. 1 through 5 show the tool 20 comprising the invention as having an elongated handle 22, a fixed jaw 24 attached to handle 22, a pivoting handle 26, a body 28 connected pivotably to both handles 22 and 26 by pivot pins 30 and 32 (32 not visible in FIG. 1), and an adjustable jaw 34 slidably mounted on body 28. Jaw 34 is attached to body 28 by two pins 36 and 38 which slide freely within an elongated slot 40 in body 28. The two pins 36 and 38 are connected to both sidewalls 42 and 44 (44 is visible only in FIG. 4). Pin 38 is somewhat smaller in diameter than the width of slot 40 so that jaw 34 may pivot on pin 36 so that serrations 66 may be lifted enough to clear serrations 68 during the adjustment of jaw 34. Sidewalls 42 and 44 are attached to jaw 34 by three pins or rivets, 46, 48, and 50, or by welding or braising. An adjusting lever 52 is pivotably attached to handle 26 by a pivot pin 54. The forward end of lever 52 is slotted and forms a yoke whose arms 56 and 58 are angled away from each other in the shape of a "V". Arms 56 and 58 straddle a pin 60 that is attached to the rear lower portion of jaw 34. The rear end of lever 52 is moved back and forth with the thumb of the hand holding the tool to slide jaw 34 along rail 64 toward or away from fixed jaw 24. The angle of arms 56 and 58 perform the function of lifting the rear end of jaw 34 the necessary distance to clear serrations 66 over serrations 68 during the movement of adjustable jaw 34 toward fixed jaw 24 when closing the jaws. When jaw 34 comes in contact with a work piece, it is tilted backward and engages serrations 66 with serrations 68, whereupon handles 22 and 26 are squeezed together to activate the locking action. Reversing the travel of adjustable jaw 34 with adjusting lever 52 to open the jaws produces the same lifting action to again clear the serrations on adjustable jaw 34 over the serrations on rail 64. A spring 70 is attached to body 28 at one end and to handle 22 at the other. A fulcrum bar 72 is pivotably connected at one end to handle 26 by a pivot pin 74 and at the other it butts up against an end of a very stiff spring 76 which is disposed internally in elongated handle 22. Spring 70 maintains the necessary tension between fulcrum bar 72, handle 26, and body 28 so that the toggle action that locks the jaws on an object will work. When handles 22 and 26 are pressed together, the fulcrum point at pin 74 is forced to pass between pivot points established by end 78 of fulcrum bar 72 and pin 32 that attaches pivoting handle 26 to body 28, thereby causing body 28 to pivot on pin 30. This pivoting action causes adjustable jaw 34 to move toward fixed jaw 24, producing the locking action on the work piece. In this instance, spring 76 is held in position within handle 22 by two inwardly projecting parts 80 and 82 in both sides of handle 22. Spring 76 performs a unique function in that a much wider range of travel for adjustable jaw 34 is possible in which a locking operation can be successfully completed. For example, in a locking tool having a screw as the adjusting means, the fulcrum bar is blocked by the screw which has no resiliency. Therefore, there is no movement of the fulcrum bar possible when both jaws are put into contact with a work piece, so the adjustable jaw has to be stopped just short of the work piece, leaving the clearance necessary for the toggle action to work and effect a locking of the jaws on the work piece. Because this clearance is so limited, it is the reason why locking tools having the screw adjustment must usually be adjusted several times before the proper clearance is obtained to lock the jaws. In the present invention, however, both jaws 24 and 34 (and their alternates) can be put into contact with a work piece and when handles 22 and 26 are squeezed together, fulcrum bar 72 can still travel far enough to permit the toggle action to work due to the compression of spring 76. If the adjustable jaw 34 is adjusted to where it is just lightly touching a work piece, a light grip will result; and if the adjustable jaw is pressed hard against a work piece, the serrations on jaw 34 will be moved forward another notch in the serrations on rail 64, thereby effecting a much stronger and tighter grip.

A lever 84 for unlocking jaws 24 and 34 is attached to pivoting handle 26 by pin 86. A spring 88 encircles pin 86 and is biased against lever 84 and handle 26 to hold lever 84 in operable position. When the outer end of lever 84 is pulled inward toward handle 22, the inner part of lever 84 pushes against fulcrum bar 72 and spreads handles 22 and 26 which unlocks jaws 24 and 34 and releases the tool from a work piece. A stop wall 90 on body 28 limits the pivot of Handle 26, keeping handles 22 and 26 within normal gripping range of each other.

FIG. 6 shows an alternate preferred embodiment of adjustable jaw 34. Jaw 34a is shown as having a notch 92 cut or formed therein into which pawl 94 is attached with screw 96. It will be noted that in this embodiment pawl 94 has a single engaging tooth 98, although multiple serrations may also be used. It will also be noted that in this embodiment the sidewalls of jaw 34a are not separate and attached by pins or other means but are integral with the jaw. This makes the jaw much easier and cheaper to manufacture as a single unit because there are no internal teeth or serrations formed as a part of the jaw. Therefore, a straight cut can be made through the jaw to form the bifurcation.

FIG. 7 shows a second alternate preferred jaw configuration wherein jaws 24a and 34b have straight serrated gripping surfaces 100 and 102.

To operate the tool, handles 22 and 26 are spread apart the maximum amount which opens jaws 24 and 34 to their maximum gap. The jaws are then placed around a work piece and adjusting lever is moved in a clockwise direction with the thumb of the hand holding the tool. This movement slides adjustable jaw 34 toward fixed jaw 24 until it contacts the work piece. As described previously herein, a light touch will result in a fairly light grip, and heavy pressure will result in a very tight grip, at the option of the operator. Handles 22 and 26 are then pressed together, locking the jaws on the work piece. To unlock the jaws, the little finger of the hand holding the tool pulls on release lever 84 which spreads handles 22 and 26 and releases the jaws from the work piece.