Patent Application
20120256362
I. Field of the Invention
This invention relates generally to an improvement in engineers' vises or the like, and more particularly to master jaw assemblies for the quick removal and attachment of hard and soft jaws.
II. Discussion of the Prior Art
An engineer's vise is used in metalworking applications. An engineer's vise, like a woodworking vise, is used to hold a work piece. Vises have one fixed jaw and another parallel jaw which is moved towards or away from the fixed jaw by a screw. In an engineer's vise, jaws are made either of hard or soft metal. Hard jaws are available with either a coarse gripping surface or are ground flat and smooth. Hard jaws can lead to deformation and error of the finished work piece if the vise is over-tightened, or if the operator is unskilled or negligent in his handling of the work piece around hard jaws. Soft jaws, in contrast, are usually made of a soft metal such as aluminum, plastic or wood. Soft jaws are used to hold delicate work pieces, and can be cut to hold specially shaped work pieces. Soft jaws are typically discarded or recycled after multiple uses.
Because soft jaws are consumable items, it is desirable that they be susceptible to rapid changeover. This requires that soft and hard jaws be prepared for attachment to both the parallel movable jaw and the fixed jaw of the vise. In the prior art, attachable jaws were typically attached to the parallel movable jaw by bolts, requiring holes be drilled into each detachable jaw. U.S. Pat. No. 4,251,066 (“the '066 patent”) teaches providing a master jaw assembly including a locking jaw having a means providing a dovetail groove along an inner side for receiving a dovetail of approximately the same cross-section on the outer side of a detachable jaw. The detachable jaw is fastened to the locking jaw by providing a weakened section of the locking jaw, such as a slot, extending along the base of the groove intermediate of the tapers. One or more pins connect the tapers on opposite sides of the weakened section for movement toward and away from one another. When the dovetail is inserted into the groove, the detachable jaw is attached to the locking jaw.
The approach of fastening the detachable jaw to the locking jaw after attachment in the '066 patent has manifest problems. First, the assembly of the '066 patent is incapable of front loading the detachable jaw and requires that the detachable jaw be inserted from the side. Second, it weakens the structural integrity of the locking jaw. After repeated use of moving the tapers back and forth, the locking jaw will distort and weaken so as to be unusable for its intended purpose. Third, because the locking jaw is made of a metal of greater strength than a soft detachable jaw, a great deal of force is required to pull the tapers toward each other to securely capture the dovetail of the detachable jaw. This will strain the operator and add to the time necessary to change out the detachable jaw. Fourth, the fastening approach of the '066 patent will still allow the detachable jaw to slip inside the dovetail groove if the pins do not adequately tighten the locking jaw to pull the tapers toward one another. Fifth, because the pins are placed on either side of the weakened segment of the locking jaw, the tapers will bow in the middle so that the groove will not conform to the cross-section of the dovetail.
It is accordingly a principal object of the present invention to provide a vise where the detachable jaws can be more easily fastened or clamped to locking jaw.
Another object of this invention is to provide a vise where the detachable jaws are comparatively inexpensive.
An additional object of the present invention is to provide a vise where the detachable jaw may be front loaded into the locking jaw.
Another object of this invention is to provide a vise where the detachable jaw may be releasably attached to the locking jaw with less time and effort.
Still another object of this invention is to provide a vise where the detachable jaw may be securely attached to the locking jaw.
A further object of this invention is to provide a vise in which a soft detachable jaw need not be provided in standard lengths, but instead may be cut from stock of the length required to mount a particular work piece.
A further object is to provide an attachment for converting an existing vise of this type to a vise adapted to accomplish one or more of the above noted objects.
These and other objects are accomplished, in accordance with the illustrated embodiment of the present invention, by providing a master jaw assembly used in a vise that comprises a locking jaw having a groove extending along an inner side of the hard jaw between a top surface and a bottom surface. The groove has a base and is defined by first and second opposing edges. The first edge is flat and the second edge is tapered toward the inward and downward base. The master jaw assembly further includes a detachable jaw with a dovetail protrusion along one side surface thereof. The protrusion is substantially the same width as the groove. A fastening device is disposed in the locking jaw along the first edge.
In accordance with the present invention, the fastening device includes a plurality of bores cut into the base of the locking jaw, a plurality of nut holes cut into a top surface and intersecting the first edge of the locking jaw. A plurality of studs is provided with a right-hand threaded segment, a left-hand threaded segment and an unthreaded segment separating the threaded segments. The right-hand threads are screwed into the bores in the base and a nut operatively engages the left-hand threads of the stud. The nuts further include a downwardly tapered edge. When the dovetail protrusion is inserted into the groove, one edge of the dovetail protrusion engages the tapered edge of the locking jaw, and the other edge of the dovetail protrusion engages the downwardly tapered edge of the nut. The detachable jaw is fastened to the locking jaw by torquing the studs further into the bores and the nuts are pulled through the nut holes and the tapered edges of the nuts engage the dovetail.
The foregoing features, aspects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of an embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several views refer to corresponding parts:
The following discussion is presented to enable a person skilled in the art to make and use the present teachings. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the present teachings. Thus, the present teachings are not intended to be limited to the embodiments shown, but are to be accorded the widest scope consistent with the principals and features disclosed herein.
As shown in
A clamping means is provided to securely fasten the locking jaw 20 to the detachable jaw 22. The clamping means includes a specially shaped nut 54 having an inwardly and upwardly tapered edge 56 when viewed as in
When the dovetail protrusion 52 is inserted into the groove 24, the inward and downward tapered edge 34 engages one side of the dovetail protrusion 52. When screwed downward by torquing the studs 58 clockwise, the nuts are lowered into the nut holes 36 and the inwardly and downwardly tapered edges 56 thereof come into engagement with the opposing side of the dovetail protrusion 52. Tightening the studs 58 further in a clockwise direction places a downward force on the protrusion 52 and securely clamps it between the inward/downward taper 34 and the inward/upward tapered edge 56 of the nuts 54, and thus clamp the detachable jaw 22 to the locking jaw 20. Turning the studs 58 in the opposite direction will raise the nuts 54 and permit the portions of the detachable jaw to be inserted or removed from the groove 24.
This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.
