GB2288357A - Clamping device - Google Patents

Abstract

A clamping device or vice comprises a base member (B) which may include slots (B1) for bolting to a workbench or machine tool (not shown). The base has a lug L with a threaded bore which threadably receives a jack-screw J having a tommy-bar (T). A movable jaw member (M) in the form of a slide has two upstanding spaced abutment jaw parts (A1 and A2) the assembly being slidable in the confines of the base (B) and movable therealong by the jack-screw (J). A fixed abutment (A3) is secured to the base (B) between the abutments (A1) and (A2). Fixed abutment (A3) may have pre-set fixed positions (A4) on the base (B) and jaw part (A1) and/or (A2) can be made removable. The construction permits a wide range of workpiece widths to be clamped in a compact overall length. <IMAGE>

Description

TITLE A Clamping device or vice This invention relates to a clamping device and particularly to a clamping device in the nature of a vice for holding work pieces during operations carried out thereon.

Vices which are intended to be used to hold workpieces may be bench mounted or mounted on machine tools or may form an integral part of such a tool and are required to have sufficient width of opening of the jaws of the vice in order to accommodate workpieces of widely varying size.

One of the objects of this invention is to provide a vice which is of compact size but which may nevertheless accommodate workpieces of widely varying dimensions.

It is another object of this invention to provide a vice which can selectively clamp work pieces of two substantially differing sizes using only limited adjustment of a movable jaw member.

In accordance with one aspect of this invention, there is provided a vice or clamping device comprising a base member for attachment to a bench or like support structure, a moving jaw member comprising two spaced work piece engaging abutments or moving jaws interconnected and further coupled with a screw-jack whereby the jaw member and both abutments may be moved back and forth along the base member by rotation of the jack, a fixed abutment or jaw on the base member and positioned between the two spaced abutments, the fixed abutment forming one clamp means in conjunction with one moving abutment and a second clamp means in conjunction with the other moving abutment.

With such a constructional arrangement two vice jaws are provided forming the clamping means, one pair of jaws being movable from a fully closed position to a first spaced position and the other pair of jaws being movable from the first spaced position to a second spaced position.

In a further development and modification of this invention one of the moving jaws may be omitted, thus the screw-jack can be coupled with the one moving jaw by means of a sliding bridge passing beneath the fixed jaw whereby the moving jaw is drawn towards the fixed jaw to effect clamping.

Preferably the screw-jack has threading engaging a flange on the base member. Alternatively the screw-jack has threading engaging a flange on a moving jaw or the interconnection therebetween.

In accordance with a second aspect of this invention, there is provided a vice comprising a base member adapted to be secured to a work bench, machine tool or the like structure and having mounted thereon for longitudinally sliding movement a moving jaw cooperating with a fixed jaw connected to the base member, the moving and fixed jaws being in face to face disposition and defining therebetween a workpiece retaining gap of variable width, a rotatable shaft mounted on the base member and having an end thereof adapted for engagement with a rotatable member with the shaft including a threaded portion embraced by a complementary threaded portion attached to the base or to the moving jaw whereby a rotation of the shaft causes the moving jaw to be moved towards or away from the fixed jaw.Preferably the base member includes a plurality of spaced locations at each of which the fixed jaw may be secured, the arrangement being such that the pitch between said fixed locations is substantially equal to or less than the maximum range of movement of the moving jaw.

In the construction of the second aspect of this invention the shaft may threadably engage the base member in which case the shaft moves longitudinally relative thereto or the shaft may threadably engage a fitting on the moving jaw and be rotatably mounted in bearings in the fixed jaw. Either arrangement may have advantages for specific applications.

A construction of this kind, and in accordance with this invention, provides for a compact vice which needs to only offer a range of adjustment of the moving jaw through rotation of the shaft which is limited and sufficient to allow a workpiece to be inserted and thereafter clamped. For workpieces of substantially differing sizes the fixed jaw may be selectively positioned on the base member in any one of a selected number of positions sufficient to accommodate a workpiece when the moving jaw is opened to its maximum extent.

In a preferred embodiment of this invention, the moving jaw is drawn towards the fixed jaw by means of the screw thread on the shaft. It is however equally possible for the other moving jaw of the first aspect to be omitted and the jaw then pushed forward towards the fixed jaw by said shaft.

A construction in accordance with this invention and a modification thereof is explained and described more fully in conjunction with the accompanying drawings showing a preferred embodiment as an example.

In the drawings Figure 1, is a side view of a first embodiment in a first jaw position, Figure 2, is a view in a second jaw position, Figure 3, is a perspective view in the position of Figure 1, Figure 4, is a plan view in the second position.

Figure 5, is a plan view of a modified construction, and Figure 6, is a section on VI - VI of Figure 5.

Referring to the drawings a clamping device or vice comprises a base member B which may include slots B1 for bolting to a workbench or machine tool (not shown). The base has a lug L with a threaded bore which threadably receives a jack-screw J having a tommy-bar T. A movable jaw member M in the form of a slide has two upstanding spaced abutment jaw parts Al and A2 the assembly being slidable in the confines of the base B and movable therealong by the jack-screw J. A fixed abutment A3 is secured to the base B between the abutments Al and A2.

With this construction the jack-screw when adjusted over its range may change the spacing of abutments Al and A3 from the position shown in Fig 1 to the position shown in Fig 2 whilst simultaneously changing the spacing of abutments A2 and A3 from the position shown in Fig 1 to that shown in Fig 2. Thus the clamp has a wide adjustment range defined by the two pairs of abutments for a lesser range of movement of the jack-screw J.

In a modification of the vice and as shown in Figure 4 the fixed abutment A3 may have pegs on the underside which engage with holes A4 in the base B thus making the abutment A3 movable in pre-set steps to accommodate more widely different widths still using the relatively short jack-screw throw. The base B may have a series of holes A4 along each side of the top surface for such a purpose.

The holes may be threaded to be engaged by screws or bolts A5.

In such an arrangement as described above jaw A1 may be omitted if a double clamping area is not required.

The jack-screw J can then act directly on the slide M or a part of the slide may be threaded to receive the jackscrew which is rotatably mounted in a bearing on the base B.

An advantage of the constructions of this invention is not only the compact construction but also the stability afforded by the slide M in the base B which remains supported over the full adjustment range.

Reference is now made to a modification of the construction hereinbefore described and with reference to Figures 5 and 6 of the drawings. As shown in these figures, a base plate 50 is provided which has spaced parallel upstanding side walls 51. Located between the two side walls 51 is a platform 52 which slides in the longitudinal direction. The platform 52 may have profiled edges for example in the form of a dovetail which engages complementary profiles in the side walls 51. As an alternative the platform may simply rest on ledges provided on the underside and in the side walls 51. A front wall 53 of the base includes a bearing arrangement 54 in which a threaded jack-screw spindle 55 is mounted. The jack-screw may be rotated by a tommy bar 56. The other end of the jack-screw is mounted in a bearing assembly 57 on an upstanding lug of the base 50.

A threaded nut or runner 58 is provided which embraces the jack-screw 55 and this nut engages an appropriate recess 59 on the underside of platform 52. It will be understood that the nut 58 engages the recess 59 in a manner whereby it is not rotatable relative thereto.

Thus by this arrangement rotation of the tommy bar 56 causes the nut 58 to move along the jack-screw, thus moving the platform 52.

At each end of the platform 52, an abutment forming a jaw 60 and 61 are provided, these being secured to the platform either by a peg and dowel arrangement or alternatively by screws 62. The clamping jaws 60, 61 may thus be removable or alternatively capable of location in different positions on the platform 52 by the provision of a plurality of screwed recesses into which the screw 62 may locate. The outer ends of the jaws 60, 61 may extend to lie over the side walls 51 and to bear thereon. Such a construction provides improved stability and load bearing.

A fixed clamp jaw 63 is provided which is secured in a respective one of a series of apertures 64 provided in the upper surface of the side walls 51 and this jaw 63 bridges the span across platform 52. The jaw 63 therefore defines one vice-like clamping area in conjunction with jaw 60 and a second clamping area in conjunction with jaw 61.

One of the advantages of this construction over the first described embodiment is that the jack-screw 55 remains in a fixed position relative to the base member and thus the overall length of the vice is compact in relation to the clamping opening available which is in contrast to known art.

For heavy duty application such as for use with machine tools, the construction may be of steel with machined profiles provided between the sliding platform 52 and side walls 51. For lighter use such as joinery, the device could be constructed from light metal such as an aluminium casting or alternatively fabricated from hard wood.

In a further modification (not shown) the fixed jaw 63 has parts which extend beyond the side walls 51 and which depend to engage thereover with securing means operative in a horizontal direction to engage the side walls to provide fixing. Such means could comprise spring loaded plungers with the jaw 63 having profiled parts running in tracks to the side of each side wall 51 whereby the jaw 63 is movable longitudinally but is captive.

Needless to say, the bearings 54, 57 in which the jack-screw is mounted can be precision bearings such as machined bushes, ball or roller bearings. A more positive means of engagement between the jack-screw and moving platform 52 may be provided, for example the platform may have an integral collar with machined threading therein in order that adequate clamping force may be transmitted.

Claims (7)

1. A vice or clamping device comprising a base member for attachment to a bench or like support structure, a moving jaw support member comprising two spaced work piece engaging abutments interconnected and further coupled with a screw-jack whereby the jaw member and both abutments may be moved back and forth along the base member by rotation of the jack, a fixed abutment or jaw on the base member and positioned between the two spaced abutments, the fixed abutment forming one clamp means in conjunction with one moving abutment and a second clamp means in conjunction with the other moving abutment.

2. A vice comprising a base member adapted to be secured to a work bench, machine tool or the like structure and having mounted thereon for longitudinally sliding movement a moving jaw support member cooperating with a fixed jaw connected to the base member, the moving and fixed jaws being in face to face disposition and defining therebetween a workpiece retaining gap of variable width, a rotatable shaft mounted on the base member and including a threaded portion embraced by a complementary threaded portion connected with the base or the moving jaw member whereby a rotation of the shaft causes the moving jaw member to be moved towards or away from the fixed jaw.

3. A vice in accordance with Claim 1 or 2 wherein the moving jaw member comprises a platform which slides between spaced abutments in the base member.

4. A vice in accordance with Claim 4, wherein the base member has spaced, parallel upstanding walls which locate, for sliding movement, the moving jaw support member which forms a carriage, the screw jack being rotatably mounted in spaced bearings in the base member with a nut or runner on the screw-jack between said bearings, the nut or runner being connected to the carriage.

5. A vice comprising a base member, a platform supported by and slidably mounted between spaced runners at the sides of the base for longitudinal movement, a screw threaded spindle rotatably mounted in the base and projecting from the front thereof, the spindle being operatively coupled to move the platform longitudinally by rotation thereof, an abutment upstanding from the platform and movable therewith forming one jaw and an abutment mounted on the base between the runners and bridging the platform and forming a second jaw.

6. A clamping means or vice constructed and arranged to function as described herein and exemplified with reference to Figures 1 to 4 of the drawings.

7. A clamping means or vice constructed and arranged to function as described herein and exemplified with reference to Figures 5 and 6 of the drawings.