According to this invention a vice comprises first and second jaws and clamp means for effecting relative movement between the jaws in a direction to clamp a wor piece between the jaws, the clamp means comprising unthreaded mechanical means for applying a final clamp¬ ing pressure. The unthreaded means may comprise cooperable surfaces inclined to the direction.

The first jaw may comprise inner and outer parts respectively having said surfaces inclined to the direction, and means for moving the outer part relative to the inner part.

The inner part may comprise a conical surface cooperable with a surface on a clamp element movable by rotation of the outer part about an axis offset from the axis of the conical surface. The invention also provides a clamp mechanism for use with a vice having first and second jaws with means for effecting relative movement between the jaws in a direction and comprising a rotatable outer member providing a surface inclined to the axis of rotation and operatively connected to a clamp element having an inner operating surface.

From another aspect the invention provides a vice having first and second jaws, means for effecting

relative movement between the jaws in a direction, the first jaw having clamp mechanism comprising inner and outer elements cooperable by unthreaded means, the outer element being rotatable to move the inner element axially and apply a clamping pressure.

The inner element may have an inner surface engaging a conical inclined surface with line contact, rotation of the outer element about an axis offset from the cone axis rolling the line contact around the conical surface. The invention may be performed in various ways and one specific embodiment with possible modifications will now be described by way of example with reference to the accompanying drawings, in which:

Pig. 1 is a plan view of a vice; -Pig. 2 is a part-section of part of a modified vice on an enlarged scale; pig. 3 is an exploded perspective view of part of

Fig. 2 on an enlarged scale; and Fig. 4 illustrates an operating feature. A vice 10, which may for example be associated with a pillar drill, has a base 11 on which is mounted a fixed jaw 12 having an operating face 13 and a movable jaw 14 having an operating face 16.

In known manner the jaw 14 is in sliding engagement with parallel guides 19 fixed to the base 11 so that the jaw 14 can be moved to and fro as indicated by arrow A. The jaw 14 is moved by an externally threaded rod 21, rotatable by a handle 22, which extends through the jaw 14 and is in threaded engagement in a bore in a boss 23

upstanding from the base 11.

In tightening such a vice considerable force may ha to be applied to the handle 22, and a greater initial force be required to release the grip of the vice becaus of frictional effects, particularly between the threads the rod 21 and the boss 23.

In the present case a clamp block 30 Fig. 2 is associated with outer end of the jaw 14, which has a fla outer face 31 at right angles to the axis 32 of the rod 21 and arrow A.

The jaw 14 has an outwardly extending boss 33, with head 33a, located in a recess 34 on the inner face 35 of the block 30 so as to resist relative rotation between th parts 14, 30. The boss 33 could be square section. The rod 21 passes through unthreaded bores 36, 37 in parts 14, 30, the bore 37 being of enlarged cross-section in its outer region 37a to provide an annular shoulder 38 engageable by a shoulder 39 on an enlarged head 40 of the rod 21. A bore 41 is formed in the block 30 diametricall opposite recess 34 with the axis 42 of the bore 41 ^' and th centre of the recess 34 being equidistant from rod axis 32.

The bore 41 need not be opposite the recess 34 but should be on the opposite side of rod 21 to the recess 34 as viewed in Fig. 2.

The bore 41 and recess 34 need not be equidistant from the axis of rod 21; for example the axis 42 may be

three times as distant from the axis of the rod 21 as is the centre of the recess 54.

The outer part 43 of bore 41 is of reduced cross- section to provide an annular shoulder 44 at the base of the inner part 45 of the bore 41.

The outer face ^' 31 of the jaw 14 opposite the bore 41 is provided with a boss 46 having an inner cylindrical part 47 Fig. 4 and an outer conical part 48 and providing a conical surface 50. The conical part could have a flat top 49.

A clamp mechanism 51 comprises a rod 52 which is a close rotatable fit in the bore 43 and has an outer handle 53 held on the rod 52 by releasable jaws 54 under the control of a captive threaded bolt 56 having a stem 55 extending into the jaws. The rod 52 has axis 57, offset from axis 42 by distance x _*

A thrust bearing 58 is received on the rod 52 in the bore 45 and engages the shoulder 44. The inner end of the rod 52 has a circular plate 59 with an outer flat face 60 at right angles to the axis 57 and engageable by the thrust bearing 58. The inner flat face 61 of the plate 59 is at an acute angle oi_ to a transverse plane at right angles to the axis 57. The angle of the conical surface 50 to a transverse plane at right angles to the axis 42 is also ^ . The inner face 61 has a cylindrical boss 62 which has a flat inner face 63 parallel to the face 61. The boss 62 has axis 62a Fig. 4.

A disc 64 has a generally flat inner face 65 engageable with the conical surface 50 and has an outwardly extending central boss 66 having an outer flat surface 67 parallel to surfaces 65 and 63 and held space from the surface 63 by a thrust bearing 68 received on the bosses 62, 66.

With this arrangement, if the handle 53 is rotated through 180° from an undamped position, in which the disc 64 is in the full line position of Fig. 4, to a clamped condition shown in chain-dotted line, the centre 64a of the face 65 is moved axially by distance Y in relation to the boss 46 because the line contact 65a of the disc 64 with the surface 50 rolls round the surface 5 in moving between the positions. The disc 64 does not rotate on its own axis but the line contact moves round the conical surface 50. As the handle 53 is rotated, in addition to axial movement of th jaw 14, the block 30 pivots slightly, the recess 34 permitting this, and pressure is applied to the jaw 14 through the boss 33 as well as through the boss 46. The engagement between the teeth of rod 21 and the boss 23 is tightened by this final closing movement of the jaw 14 but, when the vice is opened, the handle 53 is first rotated to its undamped position before the handle 22 is operated.

In operating the vice, the handle 22 is operated to close the jaw 14 on a workpiece and the handle 22 is tightened with reasonable fores, and a final clamping is

effected by rotating the handle 53 which is operable independent of handle 22. Because the mechanism 51 does not involve interengaged threads the force required to rotate the handle 53 to apply and release the clamp mechanism 51 is reasonable and the clamp is generally smoothly operable.

The clamp mechanism 51 can readily be fitted to existing vices by removing the conventional outer boss 70 Fig. 1 and providing the jaw 14 with bosses 33, 46. The rod 21 may need to be extended.

Block 30 may be reduced in axial length to ease manufacture.