Clamping Tool

Abstract

A clamping tool has a housing with a chamber therein open at one end. A multiplicity of bars is disposed in the chamber, the bars being individually displaceable inwardly of the housing against the spring action of a pad member filled with a compressible and/or displaceable medium, whereby fitting the tool to a component to be gripped thereby causes only the bars aligned with the component to be displaced into the chamber, the surrounding bars remaining immobile to grip around the component. The tool can form a spanner, a chuck, a vice clamp jaw, or a coupling means with one or more housings and associated bar assembly.

Description

BACKGROUND OF THE INVENTION

A clamping tool for form-lockingly holding components of varying shapes and sizes such as screw nuts, screw heads or the like of different sizes, has been proposed, comprising a housing, an outwardly open chamber in the housing, and a pack of bars disposed in the chamber. The bars lie against each other and against the inward wall surface of the chamber, and are displaceable back into the chamber against the action of a compression spring means.

Such a tool can be used to grip a component such as a screw head or a screw nut by the bars being fitted over the component and the tool pressed thereonto, whereby the bars which are in line with the component to be gripped are caused to be retracted into the housing, while the other bars, which lie outside the outline of the component, form-lockingly grip the component, being adapted to its outside contour. By this means the component can be moved by turning the tool. The prior tools of this kind however are generally complicated and expensive, and not entirely satisfactory in operation. In one such tool, the bars are sprung individually, which also causes difficulty in production. In another tool, the bars are secured with their inward ends to a common, resilient wall extending transversely of the chamber. In both cases, it is usually difficult to achieve satisfactory engagement of the bars on the component to be gripped, resulting in delays and inconvenience.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a clamping tool which can securely and positively hold components of varying shapes and configurations.

A further object of the invention is to improve the springing of the slidable bars of the prior art tools, whereby the tool is simpler to produce and more reliable in operation.

Yet another object is to simplify the co-operation between the bars and the spring means acting thereon, and to make the movement of each bar entirely independent of the movement of any other bar.

The tool of this invention has a housing in which is provided a chamber open at one side of the housing. A pack of bars is slidably disposed in the housing, with a spring means in the form of a compression spring pad urging the bars outwardly of the chamber. The bars are prevented from sliding completely out of the chamber either by the bars adjacent the side wall of the chamber being engaged retainingly with said wall, the bars arranged inwardly of the above-mentioned outer bars being engaged with said outer bars and with each other, or by the bars co-operating with a perforated plate which retains the bars in the housing but permits them to slide inwardly of the housing.

The pad means is filled with a compressible and/or displaceable medium, to form a resilient cushion member. The resiliency of the cushion member can be controlled by means of an actuating fluid.

The tool can be used as a spanner, or as a clamping jaw for example of a vice, or as a releasable coupling member.

A tool constructed in accordance with the invention is capable of form-lockingly and securely holding components of widely different shapes and configurations; for the compression spring means according to the invention is very resilient, thereby permitting only the bars which come into butting contact with the component to be clamped, to be pushed back into the chamber in the housing, while the remaining bars which engage around the component remain unaltered in their starting position, and ensure that the component is firmly and positively held, because the filling in the spring pad means provides locally limited resiliency of the pad means due to the compressibility or displaceability of the pad means filling. The deformation of the pad means, by the movement of the displaced bars, causes the free bars to be even more firmly pressed into their starting position due to the resulting rise in pressure in the pad means. Because they are held in place in the housing, the bars no longer need to be connected to the pad means, simple abutment therewith being sufficient. For this reason the bars which are displaced back into the housing no longer affect the adjacent free bars. The spring pad means with its filling enclosed by a casing is easy to produce and can be fitted without difficulty into the chamber in the housing, so that assembling the tool is extremely simple.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of a clamping tool according to the present invention will now be described by way of example with reference to the accompanying diagrammatic drawings in which:

FIG. 1 shows a view from below of a tool in the form of a screw spanner,

FIG. 2 shows a view of the spanner of FIG. 1 in cross-section along the line II--II in FIG. 1, before the spanner is fitted to a component in the form of a screw-threaded nut,

FIG. 3 shows a cross-sectional view similar to that of FIG. 2, but with the spanner fitted to the nut,

FIG. 4 shows a view in cross-section through the housing of the tool, on an enlarged scale,

FIG. 5 shows a view in cross-section through a tool in the form of a plug-in coupling member,

FIG. 6 shows a view in cross-section through a tool in the form of a chuck for a machine tool such as a drilling machine or the like, and

FIG. 7 shows a view in partial cross-section of a bench vice.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 through 4, the clamping tool shown is in the form of a spanner comprising a lever-like handle 1 which is fixedly connected to a housing 2. The housing 2 has a cylindrical chamber which is open outwardly at one end. Disposed in the chamber is a multiplicity of thin elongate bars 3 which lie against each other. The longitudinal axes of the bars 3 lie parallel to each other and to the longitudinal axis of the chamber while the bars 3 fill the chamber of the housing 2 over the entire cross-sectional area of the chamber. The bars 3 are displaceable relative to each other and in the embodiment illustrated are square in cross-section. However, any other suitable cross-sectional shapes, such as rectangular or round cross-sections, can also be used. thus other

As clearly shown in FIG. 2, the bars extend over only a part of the chamber. The remaining part of the chamber is filled by a pad means or cushion 4 which is adapted to the chamber and which comprises an elastic casing 5 of suitable material such as plastics material, and a pressure gas or air filling enclosed in the casing 5. The pad means 4 is resilient and tus acts as a compression spring. The spring pad means 4 bears at one side against the housing, and more precisely against the bottom surface of the chamber, while the inward ends of the bars 3 bear against the otoher side of the pad means 4. The outward ends of at least most of the bars 3 terminate substantially flush with the open end face of the housing 2 (FIG. 2).

With particular reference to FIG. 4, it will be seen that the individual bars 3 are prevented from sliding out of the housing 2, or being pressed outwardly from the housing 2 by the spring pad means 4. The outer bars which lie directly against the cylindrical inside wall of the chamber are prevented from sliding out of the chamber by a recess 6' in each of the outer bars, the recesses 6' being form-lockingly engaged with a projection 6 of suitable configuration on the housing. The projection 6 is advantageously formed by an annular flange.

The bars which lie inwardly of the above-mentioned outer bars are in turn provided in annular rows at their inward ends respectively with a recess 7' and a projection 7 (progressing from the outside inwardly), so that the inwardly arranged bars are also retained in the housing 2 by the interengagement of the recesses 7' and projections 7. Each of the outer bars also has a recess at its inward end, for co-perating with a projection 7 on the inwardly adjacent bar 3.

The central bars can also be of somewhat shorter length in the central region of the chamber, so as to form a centering recess 8 as in FIGS. 2 and 4.

The above-described spanner operates in the following manner: when a component such as a nut 9 is to be held or clamped for the purpose of subsequently tightening or releasing it, the bars are displaced against the spring action of the pad means 4 from their starting position as shown in FIG. 2 into the component-clamping position illustrated in FIG. 3, when the outward ends of the bars 3 are pressed against the nut 9. When this occurs, only those bars 3 which lie within the cross-sectional region of the nut 9 are displaced inwardly of the housing (FIG. 3). The remaining bars therefore form a recess whose outline precisely corresponds to the outline of the nut 9, so that the nut 9 is held positively and can then be tightened or slackened. The nut 9 does not have to be applied to the bars 3 in the region of the centre of the pack of bars 3 or at the centering recess 8, for lateral relative displacement of the bars with respect to the nut 9 will generally not impair the clamping action of the tool. When the spanner is to be removed from the nut 9 after the nut has been slackened or tightened, the bars 3 return to their starting position as shown in FIG. 2, under the spring action of the pad means 4.

As is readily apparent, the above-described tool can be used not only for holding or clamping nuts and screw heads of different shapes and sizes, but also other components of any desired form and configuration. In particular, the tool can also be used as a chuck, as will be described hereinafter.

As is also readily apparent, the thinner the individual bars 3, the more precisely will the tool be able to be adapted to the configuration and outline of the component to be held by the tool.

The tool according to the invention is also envisaged as a releasable connecting and coupling member and as a chuck in force-transmitting shafts, for example in oil drilling apparatuses and the like, and also in bench vices and workpiece processing machines.

Referring now to FIG. 5, this embodiment of the tool is in the form of a coupling member in two parts, comprising two housings 2' and 2" which can be secured together by means of a screw-thread. A respective spring pad means 4 and bars 3 are disposed in each of the cylindrical chambers in the housings 2' and 2". However, the coupling member can also be made in one part and the cylindrical chamber can extend through the coupling member, in which case only one compression-spring pad means is provided, with one of the two assemblies of bars 3 arranged on each side of the single pad means 4.

Instead of a gas filling, the casing 5 can be filled with hydraulic oil, as is provided in the embodiment of the tool in the form of a chuck, as shown in FIG. 6. The casing 5 of the pad means 4 has connection apertures 5' and 5" for hose connection nipples 11 which extend through bores 10' and 10" in the housing 2. By means of hose connections the oil in the casing, which otherwise is too little compressible, can be displaced or can be subjected to a desired pressure, so that in this case also the resiliency of the spring pad means 4 is maintained, or possibly adjusted. The housing 2 also has an extension portion 13 in which is disposed a plug or screw sleeve 12 for connection to a manual or a mechanical drive such as a machine shaft or another connection component, for example a screw lever or handle, when the FIG. 6 embodiment is to be used as a socket or box spanner or the like. It is also possible to provide a plurality of recesses 12 at different positions on the housing, for the insertion of tools. In the embodiment of FIG. 6, unlike the construction described above with reference to FIGS. 1 through 4, the bars 3 in contact with the cylindrical inside surface of the housing carry projections 6.sup.1 at their inward ends, engaging into a recess 6 in the wall of the housing.

In machines and apparatuses which are provided with hydraulic or pneumatic equipment, the compression-spring pad means 4 of FIG. 6 can be subjected to a controlled pressure, so that a workpiece can be reliably held by the chuck.

The pad means 4 can also be filled with small, gas or air filled deformable balls which form a resilient cushion. In this case the cavities between the balls can be filled with fluid introduced by a conduit, for controlling the pressure applied to the pad means.

A particularly suitable material for filling the pad means of bench vices or the like clamping means, as shown in FIG. 7, is gas balls. Referring to FIG. 7, the tool is in the form of a bench vice 15 which has two clamping jaws 18 and 19 with clamping chucks, having substantially rectangular housings. The clamping jaw 18 is stationary while the clamping jaw 19 is movable relative thereto. For this purpose the clamping jaw 19 is displaceable on guide means 20 on a base portion 23, by means of an actuating spindle 22. The compression spring means again comprises a spring pad means formed by a resilient casing 5 and balls 17 which are enclosed by the casing 5. The balls are preferably made from resilient plastics material with a gas filling, and substantially fill the space between the bars 3 and the inward surfaces of the chamber 16 in the housing. The bars 3 of the two clamping jaws 18 and 19 are directed towards each other and project beyond the facing end surfaces of the clamping jaws so that a firm grip can be attained, even when a workpiece to be gripped is irregularly shaped. The chamber 16 is convergent in its portion 16', at an angle of about 10.degree., so as to provide a wedging action causing the balls 17 to be wedged around the pack of bars 3 when the bars 3 are pressed in axial direction in the chamber 16 by a workpiece 24 which is clamped by the clamping jaws 18 and 19, the movement of the bars 3 causing displacement of the balls 17. The pressure relationship can be controlled by displacement of the movable jaw 19 towards the stationary jaw 18, by means of the spindle 22. As the space between the balls 17 is mostly filled with fluid such as oil, a controlled pressure can also be achieved in this embodiment, by means of connection conduits 21.

Instead of the interengaged projections and recesses described with reference to FIG. 4, for preventing the bars 3 from sliding out of the housing 2, it is also possible to use a perforated plate in which the bars are guided and with which they are in abutment in the starting position, while being able to move without hinderance into the chamber when a component is gripped.

Claims

I claim:

1. A clamping tool for form-locking holding of components of varying shapes and sizes, comprising a housing forming a chamber open outwardly at one end, a bundle of slidable rods in the chamber lying against each other and against the inner surface of the chamber, each of said rods having an inner end portion within said chamber in displaceable contact with a resilient cushion, a resilient cushion in the housing urging the rods outwardly of the chamber, said resilient cushion comprising an elastic casing enclosing a compressible medium, and means engaging the rods for retaining the rods in the chamber.

2. A clamping tool according to claim 1 wherein the medium enclosed in the casing is a compressed gas.

3. A clamping tool according to claim 2 wherein the medium enclosed in the casing is compressed air.

4. A clamping tool according to claim 1 wherein the medium enclosed in the casing comprises gas-filled deformable balls.

5. A clamping tool according to claim 4 wherein the space between the balls are filled with fluid.

6. A clamping tool according to claim 1 wherein the pad means has connection conduit means whereby a fluid can act upon the filling of the pad means.

7. A claimping tool according to claim 1 wherein said means engaging the rods for retaining the rods comprises interengaging recess means and projection means formed in the chamber inner surface and on the rods which bear directly against the wall of said chamber, and interengaging recesses and projections on the other rods.

8. A clamping tool according to claim 7 wherein said recess means and said projection means are at the inward ends of said rods.

9. A clamping tool according to claim 7 wherein said recesses and said projections are at the inward ends of said rods.

10. A clamping tool according to claim 1 wherein a plurality of said housings are connected together to form a releasable coupling member.

11. A clamping tool according to claim 1 wherein a lever handle is provided on said housing.

12. A clamping tool according to claim 1 wherein said housing includes an extension portion and a connection sleeve for connecting means for driving the clamping tool.

13. A clamping tool according to claim 1 wherein the rods have a component-centering recess.

14. A clamping tool according to claim 1 which is in the form of a clamping jaw of a bench vice.

15. A clamping tool according to claim 14 wherein the bars project beyond the clamping jaw housing and extend into the resilient cushion means which comprises resilient balls, the chamber in the housing tapering conically in its portion which encloses the bars.

16. A clamping tool comprising a housing having an open compartment, a plurality of slidable rods arranged in a bundle which bear against one another, the outermost rods bearing against the inner wall of the compartment, resilient cushion means in the housing compartment for urging the rods outwardly, said resilient cushion having an elastic sleeve, a compressible medium enclosed in said sleeve, each of said rods being provided with securing means for retaining the rods in said compartment, said securing means including a recess in said rod bearing directly at the housing wall, a projection in said compartment which engages said recesses, the remaining rods interengaging with each other via step-like formations in each rod.