GB2193126A

GB2193126A - Clamping device

Info

Publication number: GB2193126A
Application number: GB08715469A
Authority: GB
Inventors: Kurt Stoll
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 1986-07-30
Filing date: 1987-07-01
Publication date: 1988-02-03
Also published as: KR880001367A; DE3625753A1; GB8715469D0; SE8702238D0

Abstract

The device comprises a mount (2,2') with a moving clamping jaw (5,5') thereon. The driven side of the clamping jaw is opposite to a supporting means (10,10'). Between the clamping jaw (5,5') and the supporting means there is a step- down thrust transmitting means with at least one transmitting member (16,16'). There is furthermore a transmitting rod (17,17') which displaces the transmitting member(s) as it moves into the step-down transmitting means, the transmitting member(s) then bearing against the supporting means (10) and acting on the clamping jaw so that the latter is shifted. <IMAGE>

Description

SPECIFICATION A clamping device The invention relates to clamping devices and more particularly to such a device comprising a mount and a clamping jaw able to be reciprocated in the direction of clamping.

Such clamping fixtures are of universal application, for example to clamp components, workpieces or other objects securely in place, to support them or to position them. The mount of the clamping device is then attached permanently or otherwise to a suitable counter-abutment, foundation or the like so that the clamping jaw is located directly adjacent to or engages the object to the handled. By then operating the clamping device the clamping jaw is moved towards the object to be clamped, that is to say in the clamping direction, and is driven against the object. In this manner the object may be held or positioned as desired. The types of clamping device so far proposed of the initially mentioned sort are for example in the form of a rack and pinion jack in which the clamping jaw is mounted on a rack moved by a crank drive.Such clamping devices do however have the disadvantage of a comparatively large overall size and of only being able to exert small clamping forces.

Other types of clamping device operate on a hydraulic principle, as for example like a hydraulic vehicle lifting jack, which are suitable for exerting somewhat higher clamping forces.

However, there is a considerable problem as regards leakage.

One object of the present invention is to devise a clamping device of the initially mentioned type which is of compact mechanical design.

A further aim of the invention is to devise such a clamping device which is readily operated and manipulated.

A still further aim of the invention is to provide such a clamping fixture which, while enabling a powerful clamping force to be produced, is not subject to leakage.

In order to achieve these or other aims appearing from the ensuing specification and claims, in the invention a clamping device is characterized by comprising: a mount, a clamping jaw arranged substantially within said mount so as to be able to be reciprocated therein along a clamping axis, a supporting means attached to the mount and arranged opposite to a driven side of said clamping jaw,-a displacing member able to be moved into and out of a transmission zone between the driven side of the clamping jaw and the supporting means, such motion entailing shifting from an initial position into a working po- sition in said transmission zone, a mechanical thrust transmitting means adapted to increase the mechanical advantage, at least one transmitting member in said transmission zone adapted to be moved by said displacing member while bearing against said supporting means and acting on said driven side of said clamping jaw so that the latter is moved outwards from said mount.

The operation of the clamping device thus no longer involves a direct action on the clamping jaw and instead for shifting the clamping jaw in the clamping direction the displacing member is moved to a greater or lesser extent into the transmission zone, where the motion of the displacing member is transmitted mechanically to the clamping jaw with a change in the mechanical advantage during such transmission so that the displacing member may be moved with less effort while nevertheless the clamping jaw may be actuated with an extremely high clamping force.

An advantage in this respect is the complete absence of leakage problems as in hydraulic systems since the force transmitting means is entirely mechanical, this also proving to be a more economical construction inasfar as there is no need for any seals. The device in accordance with the invention may be made with a very compact overall size and is therefore readily manipulated and, more particularly, may be easily moved to the site of application.

Advantageous further developments of the invention are described in the claims. In accordance with one such feature the displacing member has a displacing part with a displacing cross section increasing in a direction opposite to the direction of inward motion and which is able to cooperate with the transmission member or members and which is preferably located at the end part of the displacing member nearer the transmission zone.

This further development of the invention serves to provide a progressively increasing clamping force, this meaning that the device is less subject to wear and that the object to be clamped is more gently treated inasfar as the clamping jaw is advanced in a controlled manner onto the object to be clamped with a gentle but firm clamping action, that is to say there is no chance of a violent jarring impact on the object likely to damage same.

As part of a further development of the invention the clamping device is designed with thrust deflecting surface means which are curved or arcuate, or more particularly circularly arcuate.

This further feature means that there is a varying speed of forward motion of the clamping jaw in the clamping direction so that the clamping jaw initially has a higher speed and is then slowly and gradually moved into the clamping position. This is something that also contributes to reducing strains and wear in the device.

A further development of the invention is possible in which there are two transmitting members which are placed opposite to each other on the two sides of the longitudinal axis of the displacing member in the initial position thereof so that the displacing part of the displacing member may be moved in between the two transmitting members while simultaneously increasing the distance therebetween.

This arrangement means that there is a symmetrical placement of the transmitting members in relation to the displacing member so that there will be a symmetrical transmission of the force without any possibility of the clamping jaw running skew and jamming.

The clamping device of the invention may furthermore be so designed that the one or more transmission members are in the form of a floatingly supported structure with a circularly cylindrical form, as for example in the form of a roller. The displacing part may be in the form of a wedge of which each wedge face cooperates with a circularly cylindrical transmission member, the longitudinal axes of the transmission members being parallel to the wedge surfaces. Furthermore, the surfaces for the deflection of thrust for cooperation with the respective transmission member are formed by the outer surface or a part thereof of a cylindrical supporting member, the same being in the form of a rotatable supporting roller. The thrust transmitting surface on the clamping jaw side may in each case be formed by the outer surface of a roller rotatably supported on the clamping jaw.

These features aid in reducing the friction of the clamping device while increasing the efficiency of force transmission.

In accordance with further features of the invention the transmission zone is in the form of a closed space filled with a large number of small, loose and freely moving transmission members and delimited at one end by the clamping jaw and at the other end by the supporting means, which is preferably in the form of a support wall, and the transmission members are preferably spherical and made of steel. The supporting wall may have a passage opening for the displacing member, the displacing member being in the form of a bar.

On its driven side the clamping jaw may have a well forming part of the transmission zone or space and which preferably has a converging wall form. As part of a further feature the driven side of the clamping jaw has a well therein forming part of the transmission space and preferably having a conical wall form.

These further features are particularly advantageous as regards lowering the price of manufacture of the clamping devices. This form of the invention is furthermore characterized by a high mechanical advantage so that a small input force acting on the displacing will lead to an extremely high clamping force being exerted by the clamping jaw. This is more especially made possible by the feature of having the transmission members in the form of spheres such as metal balls.The feature of having the converging or conical wall form means that the transmission members may be displaced with only a small effort, this also being true for a further feature of the invention in accordance with which a thrust deflecting surface is provided on the supporting means and/or on the clamping jaw which as considered in the radial direction relative to the longitudinal axis of the displacing member and outwards extends as far as the opposite part of the clamping jaw or the supporting means, respectively, in such a way that the distance between the deflecting surface and the opposite part of the clamping jaw or, respectively, of the supporting means decreases in an outward direction, if the inclined deflecting surface is on the clamping jaw.

A further advantage of the clamping device in accordance with the invention is to be seen in the high operational reliability, for even if in the operating setting the driving force acting on the displacing member should fail as a consequence of a breakdown of some other part of the system, as for example owing to the failure of the air supply to an actuating pneumatic drive cylinder, the displacing member will still remain in the operative position, since no restoring forces will act on it directly.

Even if the clamping jaw is biased towards the supporting means in order to ensure its return stroke, it is essentially only transverse forces that act on the displacing member, whereas the forces acting in the longitudinal direction of this member are negligible. In normal operation the return of the displacing member may be best produced by the production of a vacuum in the pneumatic drive cylinder or bellows.

The invention will now be described in detail with reference to the accompanying drawings.

Figure 1 shows a first constructional form of the clamping device in accordance with the present invention in a perspective view with the walls of the housing only indicated by chained lines.

Figure 2 is a longitudinal section through the device as in figure 1 in plan, the section being taken on the line Il-Il of figure 1 and showing the initial setting of the displacing member.

Figure 3 shows the clamping device as in figures 1 and 2 in a manner similar to that of figure 2.

Figure 4 shows one possible application of the device in accordance with figure 1.

Figure 5 shows a further working example of the clamping device of the present invention.

Figure 6 is a lengthways section taken through the clamping device of figure 5 in the initial setting.

Figure 7 shows the same clamping device as in figure 5 in longitudinal section in the operative condition thereof.

The clamping device 1 shown in figures 1 through 4 and the clamping device 1' of figures 5 through 7 both have the same basic design for which reason the following account will use identical reference numerals for like parts for the sake of simplicity. However to distinguish them, the reference numerals applying for the construction of figures 5 through 7 are supplemented with an apostrophe.

Both embodiments of the invention 1 and 1' constituting a clamping device have a mount in the form of a housing 2 and 2'.

The housing 2 is designed in the form of a rectangular prismatic box with only one opening 3 at one end while its longitudinal sides do not have any such openings. The housing 2' as shown in figure 5 consists of two tubular sections 4 and 4a which are coaxially arranged in relation to each other and are joined by screw means so that the result is a configuration in the form of a cylinder with a step in its wall At the free end part of the section 4 having the smaller diameter the housing 2' also has an opening 3'.

A clamping jaw 5 and 5' is mounted in the housing 2 and 2' adjacent to the opening 3 and 3' so as be able to slide in the longitudinal direction 6 and 6' of the housing. It more or less forms the termination of the housing in the opening 3 and 3'. The clamping jaw 5 and 5' is located in its initial or basic setting, which is shown in figures 2 and 6, in which it is essentially completely within the interior of the housing 2 and 2', that is to say with its outwardly facing clamping surface 7 and 7' essentially flush with the limits of the opening 3 and 3'. By means of a drive means, which is still to be described, the clamping jaw 5 and 5' may be driven through the opening 3 and 3' to a greater or lesser extent into a clamping position. In what follows this direction of motion will be referred to as the clamping direction 8.The clamping jaw then engages an object 11 with its clamping surface 7 and 7' as is indicated in figure 4. Dependent on the particular embodiment of the invention it is possible for the clamping jaw to be shifted some distance out of the housing 2 and 2' even when in the non-actuated condition.

The driven side 9 and 9' of the clamping jaw 5 and 5' facing in the opposite direction to the direction of clamping is spaced from a supporting means 10 and 10' secured to the housing. It is generally in the longitudinal plane of the respective housing. In the part between the supporting means 10 and 10' and the driven side 9 and 9', which in what follows will be referred to as the transmission zone 14 and 14', there is a thrust transmitting and step down transmission means 15 and 15'. It contains at least one transmission member 16 and 16', which is able to cooperate with a displacing member 17 and 17'.This displacing member 17 and 17' is able to be shifted between a functional position as indicated in figures 2 and 6 in which it extends to a lesser degree into the transmission zone, and various different operative settings in which it extends to some extent into the transmission zone (see figures 3 and 7).

The manner of operation of the clamping device in accordance with the invention is as follows: Starting in the initial setting of the displacing member 17 and 17' and the corresponding initial setting of the clamping jaw 5 and 5' the displacing member 17 and 17' may be moved into the transmission zone 14 and 14', one or more of the transmitting members 16 and 16' of the transmission and step down means 15 and 15' being displaced to the side and they are pressed not only onto the supporting means 10 and 10' but also against the driven side 9 and 9'.Since the supporting means 10 and 10' is stationarily arranged in the housing 2 and 2' the space needed for the displacement of the transmission member 16 and 16' is created by shifting of the clamping jaw 5 and 5' in the clamping direction 8; it is in this manner that a weak or low displacing force acting on the displacing member 17 and 17' is stepped up into a high thrust transmitted and exerted by the respective clamping jaw.

A more detailed account will now be given of the working examples 1 and 1'. In the case of the clamping device 1 shown in figures 1 and 4 the geometrical form of the interior of the housing is that of a rectangular prism. The clamping jaw 5 generally has a rectangular prismatic or cubic form, its four side faces 18 parallel to the direction 8 of clamping being adapted to slide so that the clamping jaw is precisely guided on corresponding adjacent surfaces 19 of the inner wall surface of the housing. In two oppositely placed side surfaces 18 there is in each case an opening 20 extending in the longitudinal direction 6 or the clamping direction 8 and this opening receives a check pin 21 anchored in the facing wall surface of the housing.Between the check pin 21 and the check pin 21 and the side of the opening 20, facing the driven side 9, there is a compression spring 22, which biases the clamping jaw 5 into its retracted initial setting, in which the end surface 23 of the opening 20 has engaged the check pin 21 (see figure 2) cooperating therewith. The check pin 21 furthermore serves to limit motion of the clamping jaw in the clamping direction 8, which is additionally dependent on the length of the spring in the compressed state thereof.

On its driven side the clamping jaw 5 is provided with a well 24 which extends in the clamping direction 8 about as far as halfway along the length of the clamping jaw and also opens on the two unbroken or recess-free sides. It serves to receive the displacing member 17 in its different operative settings. As seen in plan view as in figure 2 with the check pins 21 above and below, the clamping jaw 5 will be seen to have a generally U-like form, the two legs 25 and 25' having the openings 20 in them and extending into the interior of the housing, the surface of the transverse bar 26 directed away from the interior forming the clamping surface 7.

The end parts of the two legs 25 and 25' of the U-like structure facing into the housing are split like forks so as to have two spaced holding prongs 29 extending in the opposite direction to the direction 8 of clamping. It is between these prongs 29 that respective rollers 30 are bearinged. Each roller extends at a right angle to the length direction 6 and in parallelism to the associated side surface 18 having the opening 20 therein. The rollers 30 are thus sunk into the respective leg 25 and 25' and have a peripheral part extending in a direction opposite to the clamping direction 8 towards the supporting means 10 from the clamping jaw 5. This peripheral part constitutes a thrust transmitting surface 31.

In the embodiment of the invention referenced 1 the supporting means 10 has as its main parts two cylindrical supporting members 32 which extend parallel to the supporting members 32 and of which each is opposite to, and spaced from, one of the rollers 30 in the basic or initial position in the longitudinal direction 6.

The two rollers 30 and the two supporting members 32 are thus arranged in the corners of an imaginary right angle. The supporting members 32 are best in the form of supporting rollers, which are supported by way of needle bearings on a pin 33, such pins 33 for their part being mounted in two opposite housing walls (at 34). The outer surface of the supporting members 32 constitutes a thrust deflecting surface 35.

The clamping device 1 comprises two transmission members 16, which are each of circularly cylindrical form and whose longitudinal axis are parallel to those of the rollers 30 and 32 already mentioned. They are spaced apart and placed on each side of the longitudinal axis 6 between the two pairs 30 and 32 of rollers, their outer surfaces each contacting the transmission surface 31 and the deflecting surface 35 of one of the two pairs of rollers.

Therefore in the basic or initial position of the clamping jaw 5 shown in figure 2 the two transmission members 16 are thus nearer to the longitudinal axis 6 than the roller members 30 and 32.

In the clamping device 1 the displacing member 17 is generally in the form of a plate, the plane of the plate extending in the longitudinal direction 6 and parallel to the axes of the rollers. In the initial setting shown in figure 2 it is largely located on the side, opposite to the clamping jaw 5, of the supporting means 10 and its end part, adjacent to the clamping jaw 5, forms a wedge-like displacing part 38, whose wedge surfaces also run in parallelism to the axes of the rollers.

In the initial setting shown in figure 2 the displacing member 17 has its displacing part 38 extending to through and between the two supporting members 32 and into the transmission zone 14, it simultaneously extending a slight extent into the space between the two transmission members 16. Thus in the initial position the members 16 are so located that their respective outer surfaces 36 engage a wedge surface 37, a transmission surface 31 and a deflecting surface 35. They are thus held in place by engagement on three sides so that they do not require any separate means for retaining them and are best arranged in a freely floating manner. It is only their length which has to be designed to correspond to the breadth of the interior space in the housing so that although they are located in the axial direction they are able to be shifted in the transverse direction.If now, in a manner yet to be explained, the displacing member 17 is shifted and moved in the clamping direction the two transmission members 16 are moved away from each other and displaced outwards in a direction athwart the longitudinal axis 6 owing to the displacing cross section of the displacing part 38 becoming larger in a direction opposite to the clamping direction. When this happens the transmission members 16 are pressed in between the two oppositely placed rollers 30 and 32 and owing to the arrangement of the supporting roller 32 so as to be stationary in relation to the housing, the clamping jaw 5 will yield and be moved out in the direction of clamping.The maximum stroke of the clamping jaw 5 will be attained when the displacing member 16 is in the operative setting to be seen in figure 3, in which the displacing part 38 is completely drawn through between the two transmission members 16 and is in the well 24.

In order to make it impossible for the cylindrical transmission members 16 to be displaced outwards past the apical points of the two rollers 30 and 32, there are abutment pins 40 fitted in the respective housing wall to linut the displacement of the transmission members, such pins projecting into the transmission zone 14. They may if required be in the form of adjustable threaded pins so that the motion of the displacing member may be limited.

During their displacing motion the transmission members 16 rollingly engage the wedge surfaces 37, the entrained rollers and the supporting members 32 as indicated by the arrows 44 so that there is hardly any friction, this facilitating operation. However it will be clear that all the cylindrical members 30, 32 and 16 may also be arranged so that they are not able to turn, furthermore it is not necessary for the transmission surface 31 and the deflecting surface 35 to be constituted by rol lers or rolling members.However, the fact that the surfaces 31 and 35 as seen in the direction of displacement of the transmission members, that is to say from the inside to the outside, converge and more especially are curved, as is the case with the embodiment shown, means that the clamping jaw 5 firstly moves outwards comparatively rapidly and then slowly slides into its clamping setting, there at the same time being a progressive increase in the clamping force. On the lower surface of the housing the clamping device 1 externally has an attachment means 44 which enables it to be attached to a base 45 or the like as shown in figure 4 so that this base will take up the clamping force exerted on the object 11.

In the clamping device 1' shown in figures 5 through 7 the clamping jaw 5' is in the form of a cylindrical plunger, which is slidingly mounted in the housing section 4 with a smaller diameter so that motion in the length direction 6' is possible. The clamping jaw 5' has a radially projecting annular collar 46 which runs on the inner surface of the housing and the housing section 4 furthermore has a annular abutment collar 47 projecting radially inwards, same also surrounding the clamping jaw 5. Between the two collars 46 and 47 there extends a compression spring 22' surrounding the clamping jaw 5 and which serves to bias the clamping jaw 5' into the initial position.

The supporting means 10' is in this example of the invention constituted by a supporting wall 48, which is located at the part where the two sections 4 and 4a join. It is best screwed to the section 4 and it divides the interior of the housing into two spaces, each extending towards one housing end. The space adjacent to the clamping jaw and arranged in the transmission zone 14 forms a transmission space 49, which is made up of the the part 50 of the space extending between the clamping jaw 5' and the supporting wall 48, on the one hand and on the other hand of a second space section 51, which is delimited by the surface of a well 24' in the clamping jaw 5' on the driven side thereof.

The transmission space 49 is completely tilled with a large number of relatively small freely moving loose transmission members, that are preferably in the form of steel balls.

The amount of them in the space determines the distance of the clamping jaw 5' from the supporting wall 48 in the basis setting.

The supporting wall 48 is provided with a central through hole 52 allowing the passage of the displacing member 17' preferably in the form of a rod. At its end part adjacent to the clamping jaw, this member 17' has a conical displacing end 38' which projects into the transmission space 49 in the initial setting shown in figure 6. The displacing member 17' may be moved out of this initial position by a driving means (which is later to be described) into various working settings in which it extends further into the transmission space 49.

When it is advanced in a direction coinciding with the clamping direction its displacing member end 38' will displace the transmission members 16' to the side. The number of the displaced transmission members 16' will depend on the depth of penetration of the displacing member 17' and the amount of material additionally to moved into the transmission space 49.The consequence of the displacement is that the transmission members 16' while engaging, and being supported by, the supporting wall 48 will act on the driven side 9' of the clamping jaw 5' and will accordingly move the same outwards in the clamping direction 61 Unlike the clamping device 1 the clamping device 17 has a deflecting surface 35' on the driven side of the clamping jaw 5' which forms the transition between the two sections 50 and 51 of the space and which extends towards the outside in the opposite direction to the direction 8 of clamping. Its function will be clear from the remarks made above.

The well 24' is cylindrical and it may, as is indicated in broken lines at 24" also be made with a slightly conical form so that its cross section decreases towards the clamping surface 7'. This latter form will favor the displacement process of the displacing members 16', which will then be more readily displaced with the displacing member 17' moved into the well 24' or 24" (see the working setting indicated in figure 7) and into the section 51 of the space.

In the case of the working examples the actuation of the displacing member 17 and 17' is by way of a pneumatic actuator 53.

Operation by means of an electromagnet or by means of an electric motor would also be conceivable. For actuation there is a bellowstype actuator 55 placed between the supporting means 10 and the housing end wall 54 remote from the clamping jaw 5 or 5'. The one end face of the actuator 55 is attached to the end wall 54 of the housing while its opposite end 56 is attached to the displacing member 17 or 17'. The space inside the bellows actuator 55 is connected via a port 57 in the housing end wall 54 with a control unit 58 as shown in figure 4.

In the initial setting of the displacing member 17 and 17' the bellows actuator 55 will be in the non-extended setting and its end 56 will be in the immediate vicinity of the housing end wall 54. If now gas under pressure is allowed to flow by the control unit 58 into the interior of the bellows element the latter will be extended moving the end 56 and the displacing member 17 and 17' forwards in the clamping direction 8. The stroke of the bellows actuator is limited by the supporting means 10 and 10', which is preferably in the form of an abutment means cooperating with the end 56.

Since, whatever its setting, the displacing member 17 and 17' will practically not be acted upon by any forces opposite to the clamping direction 8 it will keep to its operative setting even if owing to some sort of fsilure the pressure in the bellows actuator should drop. Even in such a case the clamping force will be maintsined so that the invention provides a high degree of operational reliability. It is convenient if the control device has a suction line or a vacuum generator 59 to cause the retraction of the displacing member 17 and 17' by producing a negative pressure in the interior of the bellows element.

It is an advantage if the individual bellows segments of the bellows element are made of metal in order to increase the working life of the pneumatic actuator.

In the case of a further example of the invention which is not illustrated the displacing member is formed by the piston rod of a piston and cylinder actuator, which is then used in lieu of the bellows-type actuator.

The substantial advantage of the device in accordance with the invention is to be more especially seen in the fact that only small input drive forces are needed to displace the displacing member 17 and 17' and the bellows actuator may be thus operated with a low pressure. This low operating force is then converted mechanically in the thrust transmitting and step-down means 15 and 15' into a high driving force acting on the clamping jaw without involving any sealing problems as would for example be the case with a hydraulic cylinder device.

It is to be added that the clamping device 1' may obviously provided with a projecting attachment lug or the like which is preferably able to be fitted around the housing section 4 like a pipe cleat.

Claims

1. A clamping device comprising a mount, a clamping jaw arranged substantially within said mount so as to be able to be reciprocated therein along a clamping axis, a supporting means attached to the mount and arranged opposite to a driven side of said clamping jaw, a displacing member able to be moved into and out of a transmission zone between the driven side of the clamping jaw and the supporting means, such motion entailing shift-ing from an initial position into a working position in said transmission zone, a mechanical thrust transmitting means adapted to increase the mechanical advantage, at least one transmitting member in said transmission zone adapted to be moved by said displacing member while bearing against said supporting means and acting on said drivenside of said clamping jaw so that the latter is moved outwards from said mount.

2. A clamping device as claimed in claim 1 wherein said displacing member possesses a displacing cross section which increases in a direction opposite to the direction of motion into the transmission zone and is able to cooperate with at least one such transmitting member.

3. A clamping device as claimed in claim 2 wherein said displacing cross section of said displacing member is on an end part thereof adjacent to said transmission zone.

4. A clamping device as claimed in claim 2 or 3 wherein said displacing cross section is in the form of a wedge with separate wedge surfaces adapted to cooperate with respective ones of such transmitting members, such transmitting members having longitudinal axes parallel to said wedge surfaces.

5. A clamping device as claimed in any one of the preceding claims wherein the direction of motion of the displacing member and the direction of motion of the clamping jaw are both parallel to a given common line.

6. A clamping device as claimed in any one of the preceding claims wherein said displacing member is adapted to displace at least one such transmitting member outwards when in the transmission zone and substantially at a right angle to the direction of motion thereof, the distance between the transmitting member and the longitudinal axis of the displacing member increasing as the displacing member is moved into the transmission zone.

7. A clamping device as claimed in any one of the preceding claims comprising means defining a thrust deflecting surface for cooperation with said transmission member and so set that as said displacing member is moved into the transmission zone the transmission member engages such deflecting surface and the distance between the supporting means and the driven side of the clamping jaw decreases in a radially outward direction.

8. A clamping device as claimed in claim 6 wherein said thrust deflecting surface has a curved form.

9. A clamping device as claimed in claim 7 or 8 wherein such deflecting surface located on said supporting means and arranged to cooperate with such transmitting member is formed by at least part of the surface of a cylindrical supporting member included as part of said supporting means.

10. A clamping device as claimed in claim 9 wherein said supporting member is in the form of a supporting roller.

11. A clamping device as claimed in claim 7 or 8 comprising a roller mounted rotatably on said clamping jaw and having said deflecting surface thereon.

12. A clamping device as claimed in any of the preceding claims comprising such transmitting members placed opposite each other on two sides of the diaplacing member and adapted to be moved apart in step with each other as the displacing member is moved in between them.

13. A clamping device as claimed in any one of the preceding claims wherein said transmitting member is in the form of a circularly cylindrical roller.

14. A clamping device as claimed in claim 13 wherein said roller is floatingly mounted in said mount.

15. A clamping device as claimed in any one of the preceding claims comprising a multiplicity of such transmitting members in the form of freely movable, loose structures filled into said transmission zone which is defined between said driven side of said clamping jaw and said supporting means.

16. A clamping device as claimed in claim 15 wherein said transmitting members are in the form of steel balls and said supporting means includes a transverse wall within said mount.

17. A clamping device as claimed in claim 16 wherein said transverse supporting wall has a hole therein allowing the passage of said displacing member therethrough while retaining said balls to the one side thereof in said transmitting zone.

18. A clamping device as claimed in claim 17 wherein said displacing member is in the form of a bar.

19. A clamping device as claimed in any one of the preceding claims wherein said clamping jaw possesses a well therein opening into said transmission zone and forming a part thereof.

20. A clamping device as claimed in claim 19 wherein said well tapers conically so as to become narrower in the direction of clamping.

21. A clamping device as claimed in any one of the preceding claims wherein at least adjacent to said traflsmission zone said mount is made in the form of a sleeve.

22. A clamping device as claimed in any one of the preceding claims comprising a power driving means for moving said displacing member.

23. A clamping device as claimed in any one of the preceding claims comprising a fluid power actuator within said mount with an output member thereof connected with said displacing member and with an opposite end thereof attached to said mount in a fixed manner.

24. A clamping device as claimed in claim 23 wherein said power actuator includes a piston and cylinder device.

25. A clamping device as claimed in claim 23 wherein said power actuator includes a bellows-type device.

26. A clamping device as claimed in any of claims 23 to 25 wherein said fluid power actuator is arranged on a side of said supporting means facing away from said transmission zone.

27. A clamping device as claimed in any one of the preceding claims comprising means for biasing said clamping jaw towards said supporting means.

28. A clamping device as claimed in claim 27 wherein said biasing means includes a spring.

29. A clamping device as claimed in any one of the preceding claims comprising means for exhausting driving fluid from said actuator.

30. A clamping device as claimed in claim 29 wherein said means for exhausting fluid includes a vacuum generator.

31. A clamping device substantially as hereinbefore described with reference to Figs. 1 through 4 of the accompanying drawings.

32. A clamping device substantially as hereinbefore described with reference to Figs. 5 through 7 of the accompanying drawings.

33. Any novel subject matter or combination including novel subject matter herein disclosed in the foregoing Specification or Claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding claims.