Locking Plier

Abstract

A locking plier employing the over-center locking principle. A movable jaw is pivotally connected to a rigid handle which terminates in a rigid jaw and a movable handle is pivotally connected to the movable jaw. A sliding adjuster having an opening therethrough is positioned over the rigid handle and teeth along the opening mate is locking engagement with teeth along the rigid handle. A link pivotally connects the sliding adjuster and the movable handle to permit the over-center locking position when the teeth are in locking engagement.

Description

This invention relates to a locking plier and, more particularly, to a locking plier employing the over-center locking principle.

There are a number of different locking pliers presently in the market place. All of them are complex in design and employ various mechanisms such as a threadable shaft to adjust the locking plier to a workpiece. Other locking pliers employ telescoping concentric cylindrical members to permit adjusting and insure locking. A further drawback of existing locking pliers is that only a small portion of the gripping surfaces are in contact with the workpiece.

My invention eliminates these complex mechanisms by providing a simple yet efficient self-adjusting and locking mechanism. Adjustment is made instantaneously thereby permitting the average householder to readily use my locking plier. Further, my invention increases the actual surface area in contact with the workpiece which is being gripped. Because of the simplicity of design, my locking plier can be economically manufactured.

My locking plier employs the over-center locking principle of a link connecting a movable jaw and a sliding adjuster which slides upon a rigid handle. The sliding adjuster has teeth for locking engagement with teeth along the rigid handle. A rigid jaw which terminates the rigid handle cooperates with a movable jaw connected to the movable handle to grip the workpiece. A convexly shaped gripping surface increases the efficiency of the actual grip and permits use over a wide range of workpiece sizes.

In the accompanying drawings, I have shown one preferred embodiment of my invention in which:

FIG. 1 is a frontal view of my locking plier;

FIG. 2 is a frontal view of the sliding adjuster; and,

FIG. 3 is an end view of the sliding adjuster.

My locking plier is generally designated 10. Locking plier 10 comprises rigid handle 11 terminating in a rigid jaw 12, a movable jaw 13, a movable handle 14, a sliding adjuster 15 and a link 16.

The movable jaw 13 has a pivotal connection 17 to rigid handle 11 in the vicinity of rigid jaw 12. Movable handle 14 also has a pivotal connection 18 to movable jaw 13.

Sliding adjuster 15 has an opening 19 therethrough, see FIG. 3, into which rigid handle 11 is slidably positioned. The opening 19 has teeth 20, see FIG. 2, which are adapted to engage teeth 21 which extend along a surface of handle 11 to prevent the rearward movement of the sliding adjuster 15.

Link 16 has a pivotal connection 22 at one end to movable handle 14 and a pivotal connection 23 at its other end to sliding adjuster 15. When movable handle 14 is in a closed position, see FIG. 1, the pivotal connection 22 is in an over-center position with respect to pivotal connection 18 and pivotal connection 23.

The actual surfaces 25 and 26 of rigid jaw 12 and movable jaw 13, respectively, which grip a workpiece are serrated to improve gripping. Further, these surfaces 25 and 26 are convexly shaped. This increases the gripping of the plier because more of the serrated surface is in contact with the workpiece.

Both the movable handle 14 and the stationary handle 11 have slight recesses 27 and 28, respectively, in the area of their connection to link 16. This permits a free unimpaired movement of link 16. In other words, although link 16 pivotally connects to adjuster 15 and not handle 11 at pin 23, the extension of link 16 beyond pin 23 moves within the recess 28 in handle 21 as a result of the proximity of adjuster 15 to handle 11.

The operation of my locking plier is as follows. Movable handle 14 is opened and sliding adjuster 15 is slid forward until the gripping surfaces 25 and 26 of rigid jaw 12 and movable jaw 13, respectively, roughly engage a workpiece, not shown. The teeth 20 of sliding adjuster 15 then mesh with teeth 21 of rigid handle 11 in locking engagement and the movable handle 14 is closed. The pivotal link connection 22 assumes an over-center position in relation to pivotal connection 18 and pivotal link connection 23 to lock gripping surfaces 25 and 26 about the workpiece. As different size workpieces are engaged, substantially the same area of surfaces 25 and 26 are engaged because of the curvature of these serrated surfaces.

I have, therefore, provided an instantly adjusting locking plier employing the over-center principle for locking and which is simple of design and inexpensive to manufacture.

Claims

I claim:

1. A locking plier comprising a rigid handle having teeth along an inside face thereof, said handle terminating in a jaw having a gripping surface, a movable jaw pivotally connected to said rigid handle and having a gripping surface in operable alignment with the gripping surface of the jaw of said rigid handle a movable handle pivotally connected to said movable jaw, a sliding adjuster having an opening therethrough and teeth along a surface thereof defining said opening, said rigid handle being slidably positioned through said opening, the teeth of said opening adapted for locking engagement with the teeth of said rigid handle, a link pivotally connected to said sliding adjuster and said movable handle wherein the link-movable handle pivotal connection assumes an over-center position relative to the link-sliding adjuster pivotal connection and the movable handle-movable jaw pivotal connection to lock the gripping surface when said teeth are in locking engagement.

2. The locking plier of claim 1 wherein said gripping surfaces are slightly convexly shaped.

3. The locking pliers of claim 1, wherein said movable handle and said rigid handle have slight recesses therein to permit the free pivotal movement of said link.

4. The locking pliers of claim 2, wherein said gripping surfaces have serrations along a substantial portion thereof.