GB1584039A

GB1584039A - Clamping device

Info

Publication number: GB1584039A
Application number: GB5233077A
Authority: GB
Original assignee: Carl Schenck AG
Current assignee: Carl Schenck AG
Priority date: 1976-12-27
Filing date: 1977-12-15
Publication date: 1981-02-04
Also published as: DE2659080A1; DE2659080C3; DE2659080B2; JPS5382956A; JPS56644B2

Description

(54) A CLAMPING DEVICE (71) We, CARL SCHENCK AG, of Land wehrstrasse 55, Darmstadt 61, Fedral Republic of Germany, a German Body Corporate, do hereby declare the invention, for which we pary that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a clamping device for clamping a suitably shaped mem- ber.

Clamping connections are used in technology in many fieds and in many embodiments for the purpose of transmitting forces and torques Clamping between an outer and an inner part is usually brought about by mechanical means. The split or slit outer part is clamped to the inner part for example with the aid of screws, pins or other tensioning elements. These connections can be released but many tensioning elements must be used for example in order to transmit large forces. Actuation of these elements is complicated and time-consuming.

A different type of clamping connection is constituted by shrinkage joints. In these connections, the thermal expansion of a material is used, particulally of steel, or the shrinkage joints. In these connections, the thermal expansion of a material is used, particularly of steel, or the shrinkage during cooling is used in order to produce a tight connection. The inner diameter of the outer part of a shrinkage joint is slightly smaller than the outer diameter of the inner part at room temperature. By heating and thus expanding the outer part or by cooling and thus shrinking the inner part the parts to be connected may be inserted into each other. As soon as the two parts have resumed the normal room temperature or operating temperature, a tight connection is formed between the outer part and the inner part by means of re-expansion.

In general, these shrinkage connections either cannot be released or can only be released by means of special measures.

Shrinkage connections are used in order to connect round components such as shafts, axles, pins, columns etc. to hubs, wheels, rings, connecting pieces, bars and similar components.

Furthermore detachalble shrinkage connections are known in which sealing elements are arranged between the outer and inner part. These connections are released by forcing a pressure medium, e.g. pressure oil, between the inner and outer part and thus by achieving resilient expanding of the outer part. After expansion, the two parts of the connection may be assembled or displaced in relation to each other. These connections are used in order to fix the crossbars to the columns of materials tesing machines. In these connections, the surface of the faces to be connected must be of high quality.If, for example, there is damage to the surface of the columns, then the clamping connection can no longer be released easily, since, despite sealing of the connection, the high pressure required to release clamping can no longer build up between the inner and outer part. Furthermore, the columns must have specially constructed end parts for the assembly of this type of connection.

The present invention seeks to create a clamping clevice for producing a clamping connection which avoids the disadvantages of the known clamping or shrinkage connec tions, which is easily and rapidly released from the clamped component.

According to the invention, there is pro vided a clamping device for clamping a suitable shaped member, comprising a clamping body having an opening for receiving the member to be clamped, a pressure chamber in the clamping body so arranged as to enlarge the receiving opening for receiving the memeber to be clamped when pressuro is applied to the chamber.

Preferably a plurality of pressure medium chambers are provided.

In a solution in accordance with the invention expansin of the clamping body is achieved by passing a pressure medium into the clamping body itself, not between the parts to be clamped, i.e. not between the clamping body and the inner part. The pressure medium expands the walls of the pressure medium chambers in the clamping body resiliently whereby expansion of the opening of the clamping body receiving the inner part takes place when the chambers are arranged and shaped in a suitable manncr. As a result of the solution in accordance with the invention, the previous sealing and processing problems are dispensed with, both with regard to the clamping body and also with regard to the parts to be clamped.

Releasable and easily assembled clamping connections may be produced by the clamping body in accordance with the invention in a simple manner at any time.

The clamping body according to the invention is particularly advantageous because the opening receiving the inner part may have any desired cross-section whereby the arrangement of the pressure medium chambers may be selected in accordance with the shape of the opening. As a result, it is possible not only to accommodate round components such as shafts etc. in a clamping connection but also components having any desired cross-section, for example with a square or a double T-shaped crosssection. The invention facilitates simple and safe tensioning and release in their housings (hubs, bars, tensioning bodies, bearings etc.) of shafts, columns, pistons and other components of any desired cross-sectional shape.

Clamping is effected in the pressureless state of the actuating device. As a result, a safe connection can be obtained and no energy is required to maintain it and the connection remains effective even when there is a failure of the pressure.

The invention will now be described in greater detail, by way of example, with reference to the drawings, in which : - The Figures show sections of embodiments of different clamping bodies and Fig. 1 shows a cylindrical clamping body having a round opening for receiving the inner part and a single chamber for the pressure medium; Fig. 2 shows a clamping body similar to Fig. 1 but having several chambers for the pressure medium in various embodiments; Fig. 2a shows a cylindrical clamping body having pressure medium chambers distributed evenly over the periphery; Fig. 3 shows an axial section through a clamping body according to Fig. 2a; Fig. 4 shows an angular clamping body having a round opening for receiving the inner part and having pressure medium chambers arranged in pairs as well as an actuating device built on to the clamping body;; Fig. 5 shows a square clamping body having a square receiving opening; Fig. 6 shows a clamping body having a double T-shaped receiving opening.

In the embodiment according to Fig. 1, the clamping body 1 comprises a cylindrical wall 2, which has a single pressure medium chamber 5. The chamber is supplied with pressure medium via a supply line 4 from a pressure medium source not shown. For example, a shaft, a column or any desired other component having a round crosssection may be clamped in a receiving opening 5 of the clamping body. Thus it is the same whether the component is to be connected to the clamping body or whether the clamping body is to be connected to the component.

The pressure medium chamber 3 has chamber walls 6 (inner wall) and 7 (outer wall) as well as end faces 8 and 9. When the pressure medium chamber is supplied with a pressure medium, the chamber walls 6 and 7 are expanded in a circumferential direction by the pressure prevailing at the endfaces 8 and 9 and the clamping body 1 and thus the receiving opening 5 expands out. The radial distortion of the inner wall 6 towards the receiving opening 5 may be kept small by suitable shaping of the pres- sure medium chamber, for example by the arrangement of webs between the inner and outer wall, as shown in Fig. 2. Furthermore, an enlarged play may be provided for the receiving opening on the inner wall 6.

The radial distortion of the inner wall 6 may be prevented from reducing the size of the recipient opening 5 during pressure action by this type of measure.

The wall thickness of the chamber walls 6 and 7 and their length in a circumferential direction are dimensioned so that sufficient expansion of the recipient opening 5 is achieved in the pressure medium chamber at maximum pressure of the pressure medium. The clamping force of the clamping body may be changed by suitable selection of its length in an axial direction within broad limits.

The wall 2 of the clamping body does not have to have a uniform wall thickness over its periphery, as shown in Fig. 1. Other suitable shapes of wall may be selected, as indicated for example in Fig. 1 in broken lines. In general, several pressure medium chambers can be provided in one clamping body. For the arrangement and shaping of the pressure medium chambers there are many possibilities, some of which are shown in the further embodiments. In principle, the pressure medium chambers are constructed and arranged so that the desired effect, i.e. expansion of the receiving opening is obtained when acted upon by a pressure means.

In order to make the clamping connection between the clamping body and an inner part the prescribed pressure is generated in the pressure medium chambers. As a result the receiving opening expands outwards and the clamping body and the inner part are able to be joined together, displaced in relation to each other, or released from each other. After lowering the chamber pressure the clamping body draws together again and a tight connection between the clamping body and the inner part results.

Pressure medium chambers 10 to 13 are arranged opposite in pairs in Fig. 2 over the periphery of the clamping body 1. In the example shown, some different embodiments of pressure medium chamber are stated. In practice, however, the same embodiment is generally provided for all chambers in the same clamping body.

The greatest possible expansion of the clamping body should be achieved by the shaping of the pressure medium chambers (in a peripheral direction) at a given chamber pressure-while taking the desired clamping force into account. Thus the expansion of the inner chamber walls in a direction towards the receiving opening is to be inhibited as far as possible or kept as small as possible. The pressure medium chambers 10 to 13, therefore, have webs 14 to 17 which prevent inward deformation of the chamber walls (inner walls) lying towards the receiving opening 5 and thus substantially prevent a reduction of the receiving opening. The webs running radially from the inside towards the outside may have a uniform cross-section (webs 14, 16 and 17).However they may also be constructed with a thicker portion in the middle for example (web 15) or have some other shape determined for example by manufacture. By strengthening the webs, their expansion may be kept small and thus their function may be improved.

The end walls 18 and 19 of the pressure medium chambers may run approximately radially from inside towards the outside, as shown in the pressure means chambers 10 to 12, or may run parallel to each other, as shown in chamber 13. They may take on an irregular shape determined for example by manufacture.

The receiving opening 5 may be constructed with enlarged play 25 at the chamber walls of the pressure medium chambers, as is indicated with the pressure medium chamber 10. As a result, distortion of the chamber walls towards the receiving opening 5 may be balanced out and a reduction in the desired size of the receiving opening may be avoided.

In Fig. 2a, pressure chambers 20 and 22 are distributed evenly over the periphery of the clamping body. The pressure medium chambers may have a trapezoidal crosssection for example in radial section (pressure medium chamber 20) or a rectangular cross-section (pressure medium chamber 22). Accordingly there are approximately rectangular (web 21) or trapezoidal crosssections (web 23) for the webs between the pressure means chambers. The pressure medium chambers or the webs may have any desired other suitable cross-section, however.

If several pressure medium chambers are arranged in one clamping body, then the individual chambers are connected together in a suitable manner and are connected to a common pressure medium source as is indicated for example in Fig. 4.

An axial section according to Fig. 3 through the cylindrical clamping body 1, which lies, for example, along the section line A-A in Fig. 2a, shows the pressure medium chambers 20 and 22, inner and outer chamber walls 30 and 31 as well as closure parts or lids 32 and 33 of the clamping body or of the pressure medium chambers. The closure members or lids 32 and 33 may be screwed to the base body or welded thereto, for example.

Since the lids 32 and 33 do not completely follow the expansion of the base body with the pressure medium chambers when acted upon by pressure medium, an enlarged play 35 of the receiving opening is provided at the lids and possibly at the parts of the base body connected thereto. The pressure medium chambers may be connected together via a common line, as indicated at 34.

A round component 36 is clamped in the receiving opening of the clamping body. The clamping body may be closed at one end as indicated in broken lines at 37.

Fig. 4 shows a clamping body and how it may be used for example in the crossbar 40 of a testing machine which is shown only diagrammatically. The pressure medium chambers 41 are arranged opposite in pairs and are connected to a pressure medium source via a common line 42. The clamping body encircles a column 45 of a testing machine for example. Concerning the arrangement and shaping of the pressure medium chambers as well as the mode of operation of the clamping device, the comments made re Figs. 1 to 3 are valid.

Figs. 5 and 6 show that not only can round components be clamped to the clamping body in accordance with the invention but also components having substantially any desired cross-section. In accordance with Fig. 5 pressure medium chambers 50 to 53 are arranged around the receiving opening 54 in a clamping body having a square crosssection and a square receiving opening. A square component in the receiving opening 54 may therefore be clamped at all four sides. It is also possible to arrange pressure medium chambers, for example, only on two opposite sides of the square opening 54, for example, only pressure medium chambers 50 and 52. In this case the component is clamped in the receiving opening only at the sides at which there are no pressure means chambers.

In a clamping body according to Fig.6 having a receiving opening for a double T shaped profile 60, the faces 63 and 64 of the profile 60 are clamped in the shown arrangement of the pressure medium cham bers 61 and 62. Other arranggements of the pressure medium chambers are also possible.

For example the pressur means chambers may be arranged at faces 63 and 64 in the clampingg body. In this case the endfaces 65 of the profile are clamped. As large a play as desired may be provided at the remaining faces of the receiving opening.

The pressure medium chambers are generally acted upon by an hydraulic pres sure medium, for example pressrue oil.

However applications are also conceivable, for example in plastics components, in which the use of gaseous pressure means is suitable.

A special pressure medium source is not necessary in each case in order to produce the pressure in the pressure medium cham bers. The pressure medium chambers may be constantly filled with a pressure medium for example a viscous pressure medium. The necessary chamber pressure may be pro duced by an actuating device arranged on the clamping body. The actuating device may comprise, for example, a piston or a similar element which acts on a pressure medium chamber and which is actuated mechanically, for example.

In Fig. 4 this type of actuating device is shown in simplified form. It comprises a cylinder 46 built on to the clamping body having a cylinder bore 47 filled with pres sure means, in which bore a piston 48 fits in movable manner. The piston 48 is pressed into the cylinder bore 47 by an actuating screw 49. The chamber 'pressure required to make the clamping body expand may be produced via the connection line 43 in the pressure means chambers 41.

A clamping body accoring to the inven tion may be constructed together with a suitable actuating device, also as a single component for producing any desired clamping connections. Thus any desired suitable materials, for example metals or plastics, may be: used for the clamping body.

WHAT WE CLAIM IS 1. A clamping device for clamping a suitable shaped member, comprising a clamping body having an opening for receiv ing the member to be clamped, a presure chamber in the clamping body so arranged as to enlarge the receiving opening for receiving the member to be clamped when pressure is applied to the chaniber.

2. A clamping device according to claim 1, wherein a plurality of pressure chambels ls provided.

3. A clamping device according to claim 2, wherein the pressure medium chambers are arranged opposite each othe in pairs around the receiving opening.

4. A clamping device according to claim 2 or 3, wherein the pressure medium cham bers are arranged evenly distributed around the receiving opening.

5. A clamping device according to claim 2, 3 or 4, wherein the pressure medium chambers have webs running substantially from the inner wall to the outer wall of the clamping body.

6. A clamping device according to any one of claims 2 to 5, characterised in that the arrangement of the pressure medium chambers is matched to the shape of the receiving opening.

7. A clamping device according to any one of claims 2 to 6, wherein the pressure medium chambers are connected together and are connected to a common pressure medium source.

8. A clamping device according to any one of claims 2 to 7, wherein an enlarged play is provided in the walls of the receiving opening adjacent the pressure medium chambers.

9. A clamping device according to any one of claims 1 to 8, wherein the receiving opening has any desired cross-section.

10. A clamping device according to any one of claim 1 to 9, wherein the pressure medium chamber(s) is (are) filled with a pressure medium which may be acted upon by an actuating device arranged on the clamping body.

11. A clamping device according to any one of claims 1 to 10, wherein the receiving opening is closed at one end either com pletely or partially.

12. A clamping device for clamping a suitably shaped member substantially as described herein with reference to the drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. at the sides at which there are no pressure means chambers. In a clamping body according to Fig.6 having a receiving opening for a double T shaped profile 60, the faces 63 and 64 of the profile 60 are clamped in the shown arrangement of the pressure medium cham bers 61 and 62. Other arranggements of the pressure medium chambers are also possible. For example the pressur means chambers may be arranged at faces 63 and 64 in the clampingg body. In this case the endfaces 65 of the profile are clamped. As large a play as desired may be provided at the remaining faces of the receiving opening. The pressure medium chambers are generally acted upon by an hydraulic pres sure medium, for example pressrue oil. However applications are also conceivable, for example in plastics components, in which the use of gaseous pressure means is suitable. A special pressure medium source is not necessary in each case in order to produce the pressure in the pressure medium cham bers. The pressure medium chambers may be constantly filled with a pressure medium for example a viscous pressure medium. The necessary chamber pressure may be pro duced by an actuating device arranged on the clamping body. The actuating device may comprise, for example, a piston or a similar element which acts on a pressure medium chamber and which is actuated mechanically, for example. In Fig. 4 this type of actuating device is shown in simplified form. It comprises a cylinder 46 built on to the clamping body having a cylinder bore 47 filled with pres sure means, in which bore a piston 48 fits in movable manner. The piston 48 is pressed into the cylinder bore 47 by an actuating screw 49. The chamber 'pressure required to make the clamping body expand may be produced via the connection line 43 in the pressure means chambers 41. A clamping body accoring to the inven tion may be constructed together with a suitable actuating device, also as a single component for producing any desired clamping connections. Thus any desired suitable materials, for example metals or plastics, may be: used for the clamping body. WHAT WE CLAIM IS

1. A clamping device for clamping a suitable shaped member, comprising a clamping body having an opening for receiv ing the member to be clamped, a presure chamber in the clamping body so arranged as to enlarge the receiving opening for receiving the member to be clamped when pressure is applied to the chaniber.