I. Field of the Invention
The present invention relates generally to clamps and, more particularly, to lever-operated clamps.
II. Description of Related Art
There are many previously known lever-operated clamps that are used for temporarily clamping items to a structure. For example, such clamps are oftentimes used for assembly work in order to properly secure and position pieces for assembly during the assembly process. Many of these clamps are sold under the trademark DESTACO, CARR LANE, etc.
These previously known lever-operated clamps typically include a base which is secured to a substructure of some sort. One end of an elongated clamping arm is pivotally mounted to the base so that the clamping arm is movable between a hold and a release position in a circular arc. An elongated lever is pivotally mounted to both the base and the clamping arm and is operable to actuate the clamping arm between its hold and its release position.
Conventionally, an elongated bolt having an elastomeric bumper at one end is adjustably secured to or near the free end of the clamp arm so that the bolt with its attached bumper moves in unison with the clamp arm. The elastomeric bumper is positioned to engage the workpiece desired to be clamped and protects the workpiece from the clamping force.
In order to attach the bolt to the clamp arm, the clamp arm for these previously known clamps typically includes a pair of spaced apart side bars. The elongated bolt extends through the channel formed in between the elongated side walls so that the bumper protrudes outwardly from one side of the clamp arm side walls while the opposite end of the bolt protrudes outwardly from the other side of the channel formed by the clamp arm side bars.
In order to rigidly secure the bolt, and thus the bumper, to the clamp arm, a pair of jam nuts are threadably mounted onto the bolt so that one jam nut is positioned on one side of the clamp arm channel while the other jam nut is positioned on the opposite side. The user then utilizes two wrenches to tighten the jam nuts against the clamp arm thus rigidly securing the bolt and thus the bumper to the clamp arm. The actual extension of the bumper from the clamp arm is adjustable by rotating the bolt through the jam nuts prior to tightening the jam nuts.
A major disadvantage of these previously known clamp assemblies, however, is that a pair of wrenches must be used to secure the bolt with its attached bumper in an adjusted position on the clamp arm. This, in turn, provides for a rather cumbersome adjustment of the bolt with its bumper.