TECHNICAL SOLUTION The object to be worked on has to be held firmly enough, especially in metal, wood, machine-building and other industries where a higher degree of finishing precision is required.

STATE-OF-THE-ART Various solutions with a varying degree of efficiency have been applied, but none wholly satisfactory. As a rule, recourse is taken to the longest possible slide with lathes guiding the slide along the vice paths with minimum clearance. But as the clearance cannot possibly be entirely eliminated, at the final tightening stage the held object is raised and shifted from the vice base. If the workpiece is not parallel with the vice jaws, it is held at two points only, so that irrespective of the tightening force there is a risk for the cutting tool to destabilize or even knock it out of the vice. These are only some problems encountered in the existing designs. The present patent eliminates these problems.

THE ESSENCE OF THE INVENTION The primary purpose of the Invention is to ensure that the workpiece is efficiently and firmly held, always at four points or in two lines, no matter how parallel- running it is, with prevention of upward gliding, loss of parallel or vertical line in relation to the vice guides. The secondary but also vital purpose is to provide much smaller tightening forces by means of a flexibly adjustable slide. This solution is applicable to all types of vices, mechanical, hydraulic or pneumatic.

The technical novelty of the Invention is as follows: The nut holder and the truncated reverse cone-shaped nut keep the vice body and the slide together, acting, at the same time, as a pusher in the direction of tightening or disengagement, enabling the slide to rotate around the nut holder and nut axis, which in turn allows self-adjustability, whereas the conical shape of the nut

prevents the slide from rising and instead with its final tightening force brings the slide to the vice body; at this stage the vice becomes a single whole.

In terms of hydraulics as an integral part of the whole idea, the technical novelty of the Invention is as follows: The working part of the hydraulic system is extended to the joint which, turning by 90 degrees, is pushing the smaller piston which is pushing oil and through the bigger piston moves the bushing with multiple force; this, over a threaded spindle- serving simultaneously for moving the slide to and fro-is pushing the nut holder and thereby the slide in the direction of tightening.

BRIEF DESCRIPTION OF DRAWINGS The attached drawings as part of the description of the Invention illustrate the Invention's optimum design and help clarify its general principles.

Fig. 1-The All-purpose Vice as it looks in real space, with the self-adjustable slide.

"MECHANICAL TIGHTENING" Fig. 2-A-A'cross-section with all its visible parts Fig. 3-B-B'cross-section with all its visible parts Fig. 4-The nut holder and truncated reverse cone-shaped nut as it looks in real space, with a part of the threaded spindle Fig. 5-Rear part of the vice as it looks in real space, in this case with hydraulic joint tightening Fig. 6-A-A'cross-section of only the hydraulic part ending with a part of the threaded spindle having an ending identical to"MECHANICAL TIGHTENING" (Fig. 2) Fig. 7-A-A'cross-section. of only the working part of the hydraulic system in the joint position after final tightening, with the handle removed.

DETAILED DESCRIPTION OF AT LEAST ONE WAY OF APPLICATION By turning the handle (9) through the threaded spindle (5) and the screw nut, which is a constituent part of the grip body (8), the nut holder (12) is pushed forward, and through the truncated reverse cone-shaped nut (13) the slide (4) is moved towards

the workpiece which is gently engaged by touching or leaning on the hard jaw; it is followed by final tightening by means of stronger pressure exerted on the handle.

"HYDRAULIC JOINT TIGHTENING"proceeds as follows: Fig. 6 and 7: by turning the handle (19) the nut holder (12) is moved through the threaded spindle (5) and the screw nut, which is a constituent part of the bushing (29), whereas the slide (4) is moved through the nut holder and the truncated reverse cone-shaped nut (13). Following a touch with the workpiece and its gentle engagement the joint (18) is turned by means of the handle (19) by 90 degrees. Turning of the joint (18) gives a thrust to the piston (22) which exerts pressure on oil in the chamber (26), whereby via the bigger piston (27) with the sleeve (25) the bushing (29) is pushed by multiple force; in its turn the bushing (29), via the threaded nut and the threaded spindle, gives a push to the nut holder which through the slide (4) transfers force S- 1 towards tightening not allowing force S-2 to raise the slide (4) and, at the same time, enabling the slide C-C to adapt itself to the non-parallel movements of the held workpiece. When the lateral plates (6) on the slide (4) get down along the vice guides, all the above steps retain the same function, except that the slide (4) is now parallel.

APPLICATION OF THE INVENTION The Invention can help make a practical, safe, accurate and useful vice at a low cost, including essential improvements compared to the existing vices.