GB2165588A

GB2165588A - Pivoting support for cylinder

Info

Publication number: GB2165588A
Application number: GB08524174A
Authority: GB
Inventors: Kurt Stoll; Gerhard Hihn
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 1984-10-10
Filing date: 1985-10-01
Publication date: 1986-04-16
Also published as: GB2165588B; ES296434U; ES296434Y; IT8584962A0; IN166645B; SE8504664L; DE3437160A1; JPS6196205A; SE8504664D0; FR2571446B1; JPS6196204A; JPH0473001B2; JPH0574721B2; GB8524174D0; KR860003442A; FR2571446A1; IT1187485B

Abstract

A pneumatic or hydraulic piston/cylinder assembly has a support (6) for movement of the assembly. The support (6) has two support brackets (11, 12) which can be fitted to parts (22, 22') of the outer circumference (7) of the cylinder (1), which can be rigidly connected to and disconnected from each other, and which can be rigidly clamped to the cylinder (1). Each support bracket (11, 12) has at least one pivot (27, 27') for rotatable mounting in an associated bearing and movement of the assembly. The support (6) completely surrounds the cylinder (1). The two brackets may be located with respect to each other by pins (33) and clamped together by screws (29). The rods (5) running parallel to the cylinder are accomodated in cutaways (38) and are acted upon by tapering centering elements (39). <IMAGE>

Description

SPECIFICATION Pneumatic or hydraulic piston/cylinder assembly The invention concerns a pneumatic or hydraulic assembly with a cylinder tube guiding a piston and a support for a bearing enabling movement thereof.

In well-known working cylinders of the above type, supports for moving bearings of the working cylinder are situated in the area of its axial end and usually at one cylinder cover. The support contains an eye shaped on or fixed to the cylinder cover, through which a moving shaft can be pushed. The moving shaft can then be supported in bearings at both ends, so that the working cylinder can move around this moving shaft.

There is another possibility of making the moving shaft as two separate moving pivots, which are shaped on or fixed to parts of the working cylinder.

Due to the support being rigidly fixed to the working cylinder, the above-mentioned working cylinders can only be used for special areas of work. If, for example, the method of operation of a working cylinder previously supported in bearings in the area of the cylinder cover is to be modified, so that it is to be supported in bearings in the area of its centre longitudinally, then this can only be done with great expense, if at all. For example, new pivots would have to be welded on in the area of the outside circumference of the cylinder tube, which could lead to damage to the cylinder tube itself.

A purpose of the invention is therefore to create a pneumatic or hydraulic working cylinder with a support for its moving bearing, so that it can be fitted at any position along the longitudinal direction of the cylinder tube, which is easy to fit and to remove and which can easily be fitted later to other working cylinders.

According to the present invention there is provided a pneumatic or hydraulic assembly comprising a cylinder guiding a piston, a bearing support comprising two support brackets co-operable with respective parts of the external surface of the cylinder, the brackets being rigidly but releasably connectible to each other and being adapted to be rigidly clamped to the cylinder, each support bracket having a pivot arranged to be rotatably supported in a bearing with the bearing support surrounding the cylinder.

Due to the two part design of the support, it can be fitted anywhere on the outer circumference of the cylinder tube. Assembly or dismantling is done simply by connecting or disconnecting the connection between the two support brackets. After fitting, the support is securely centred on the cylinder tube, which guarantees secure movement. Even working cylinders not previously equipped with a support for movement can easily be later equipped with the support of the working cylinder.

The working cylinder has the advantage that the axis of movement can be varied without great expense, for example a support in the area of a cylinder cover can be moved to the area in the centre of the working cylinder longitudinally in a short time. The support in the area of the centre of the working cylinder longitudinally is often necessary if particular working conditions or restricted space require it.

Fitting the support does not have any adverse effect on the cylinder tube and the fixing of the support so that it can be undone requires no special construction features on the working cylinder itself.

Preferably the support brackets are Ushaped, and each can be located with the open part of the U on the cylinder, with both legs wholly or partly surrounding the cylinder.

This guarantees secure mounting and simultaneous centring of the support on the cylinder.

Preferably also the free ends of the legs of the U of the support brackets are adjacent to each other when located on the cylinder, and the legs of the U of both support brackets are adjacent on front sides and the two support brackets in the fitted state form a structure which coaxially surrounds the cylinder. This makes mounting of the suppport easier and also ensures centring on the cylinder. There can also be ensured good centring of the support brackets on the cylinder, on the one hand, and on the other hand ensure that the support bracket makes contact at the required positions on the outside circumference of the cylinder. This gives certain transfer of the clamping force occurring when connecting the two support brackets to the cylinder.

A simple movable support of the cylinder by the pivots can be made possible in a bearing block. The support brackets act as intermediate members between the pivots and the cylinder; a change of the position of the support bracket automatically causes a change in the position of the pivots. Simple manufacture of the support is possible.

As the common axis of movement of both moving pivots runs through the centre of the cylinder tube, there is a favourable distribution of forces and torques. The support brackets are hardly stressed, so that the support sits securely on the cylinder tube even in extreme situations.

Simple and reasonably priced manufacture of the support and simultanously simple and quick fitting to and removal from the cylinder tube is possible.

The position of the two support brackets relative to each other can be secured and assembly simplified. A compact construction of the support is possible. Positioning and con necting parts are integrated in the parts of the support bracket which are necessary in any case. A secure holding of the cylinder cover can be ensured, as can guiding of the support. The support brackets are simultaneously set on tie rods when locating them on the cylinder. This secures the support against turning, which also permits a correction of the position in the longitudinal position of the cylinder before fixing the two support brackets, without changing the relative position of the pivots in the circumferential direction of the cylinder.

By screwing centring elements towards the tie rods, for example, conical ends of the centring elements come into contact with the tie rods and tighten these between the centring elements and the support brackets. It is even possible to fit the support to the cylinder so that the support brackets only make contact with the tie rods and not with the cylinder. This is a special advantage if the cylinder must not be loaded for some reason.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a side view of an assembly in accordance with the invention; and Figure 2 is a section through the support of the cylinder along section ll-ll in Fig. 1.

Referring to the drawings, a pneumatic or hydraulic assembly comprises a cylinder tube 1, which is closed at both ends by means of respective cylinder covers 2, 3. A piston rod 4 projecting from cylinder cover 3 is also shown. The two cylinder covers 2, 3 are connected together by bar shaped tie rods 5 parallel to the longitudinal axis of the cylinder tube. A support 6 for the moving support of the working cylinder is set on to cylinder tube 1 and tie rod 5.

As can be seen from Fig. 2, the tie rods are situated in the area of the outer circumference 7 of cylinder tube 1 and, seen from the centre of the cylinder, are at a radial distance from the outer circumference 7. Four tie rods 5 are provided on the working cylinder and are evenly distributed over the circumference of the cylinder tube, where, as shown in the section of Fig. 2, they lie at the corners of an imaginary square or rectangle. The connecting lines of two radially opposite tie rods 5 therefore intersect at the centre of cylinder tube 1 and are at a right angle to the longitudinal axis of the cylinder tube.

The tie rods 5 are pushed or screwed into the cylinder covers 2, 3, as shown at 8. The tie rods are therefore best provided at both ends with a thread 9, which engages in the appropriate internal thread of a turnscrew 10.

Of course, any other equivalent type of fixing can be selected for the tie rods 5. Support 6 is explained in more detail below from Fig. 2.

The drawing shows the state with the support fitted to the working cylinder.

The support 6 contains two support brackets 11, 12, which are U-shaped. Each support bracket therefore has two legs 13 and 14 for support bracket 11 and legs 13' and 14' for support bracket 12. They also have respective crossbars 15, 15' connected separately to the legs and an open area 16, 1'of each support bracket.

The support brackets 11, 12 are now set with their open areas 16, 16' on to the cylinder tube 1, so that the open areas 16, 16' are opposite each other. In this condition, the free ends 17, 18 of the legs of the support bracket have their front sides 19, 19' in contact and the cylinder tube 1 is completely surrounded by the crossbars 15, 15' and the legs 13, 13', 14 and 14' of the support brackets. The crossbars 15, 15' of the support brackets are provided with respective contact surfaces 21, 21' on the insides 20, 20' towards the cylinder tube 1, which makes contact with parts 22, 22' of the outer circumference 7 of the cylinder tube 1.These contact surfaces are made arc-shaped, particu lariy in the shape of an arc of a circle as seen in the longitudinal direction of crossbars 15, 15' and their contour corresponds to the outer contour of parts 22, 22'. Also, raised contact surfaces 24, 24' are provided on the insides 23 of legs 13-14' turned towards the cylinder tube 1, where the spacing of the contact surfaces 24, 24' of two legs of a support bracket corresponds substantially to the outside diameter of cylinder tube 1.

In the state of support 6 when fitted to the cylinder tube 1, all the contact surfaces 21, 21', 24 and 24' of the support brackets are in contact at the outside surfaces 25 of cylinder tube 1 or on parts thereof.

The support brackets 11, 12 are now set with their open area 16, 16' on to the cylinder tube 1, so that the open areas 16, 16' are opposite each other. In this condition, the free ends 17, 18 of the legs of the support bracket have their front sides 19, 19' in contact and the cylinder tube 1 is completely surrounded by the crossbars 15, 15' and the legs 13, 13', 14 and 14' of the support brackets. The crossbars 15, 15' of the support brackets are provided with respective contact surfaces 21, 21' on the insides 20, 20' towards the cylinder tube 1, which makes contact with parts 22, 22' of the outer circumference 7 of the cylinder tube 1. These contact surfaces are made arc-shaped particularly in the shaoe of an arc of a circle as seen in the longitudinal direction of crossbars 15, 15' and their contour corresponds to the outer contour of parts 22, 22'. Also, raised contact surfaces 24, 24' are provided on the insides 23 of legs 13-14' turned towards the cylinder tube 1, where the spacing of the contact surfaces 24, 24' of two legs of a support bracket corresponds substantially to the out side diameter of cylinder tube 1.

Moving pivots 27, 27' are provided at this support for the moving support of the working cylinder in a bearing (not shown). They are situated at the side surfaces 26, 26' of crossbars 15, 15' of the support brackets 11, 12 away from the cylinder tube 1, and project in the direction away from cylinder tube 1. The two pivots 27, 27' are best situated along a common axis 28, which passes through the centre of the cylinder tube 1 and intersects its longitudinal axis. The pivots are therefore in the radial direction, as seen from the cylinder tube 1.

Connecting parts 29, particularly screws, are provided to connect the two supporting brackets 11, 12. One of the support brackets 11 has a penetration 30, e.g. a bore, in each of its legs 13, 14, which passes transversely through the leg in its longitudinal direction and is suitable for accommodating a connecting part 29. The longitudinal axis of the penetrations is best made parallel to the axis 28.

Openings 31 provided with threads are made in the front sides 19' of the opposite legs 13', 14', into which the connecting parts can be screwed. (For the sake of clarity only one connecting part 29 is shown drawn in Fig. 2, the other one is indicated by a dotted line) Also, a positioning cut-out 32 in the shape of a blind hole or a blind bore is made in each front side 19, 19', the longitudinal direction of which is also parallel to axis 28. The opposite positioning cut-outs of two opposite legs are aligned, so that a positioning part 33, such as a pin, can be pushed in the cut-outs. (For the sake of clarity, the positioning cut-out and part are only shown in one leg in Fig. 2) Again referring to Fig. 1. the support 6 is shown in a view along arrow I in Fig. 2. The legs 14, 14' of the support brackets 11, 12 are therefore visible with the outsides 34, 34' away from cylinder tube 1.One can see that the connecting parts 29 are arranged to be at the same distance from the sides 35, 36 of the brackets towards the cylinder covers 2, 3.

One positioning element 33 is always assigned to two legs in contact. This is situated approximately in the middle between the longitudinal axis of the connecting part 29 and one of the sides 35, 36. According to the illustration, the positioning element 33 in the area of the legs 14, 14' is situated between the connecting parts 29 and side 35 and in the area of the legs 13, 13' it is situated between the connecting part 29 and side 36. Of course any other arrangement of two positioning eie- ments can be provided per adjacent set of legs.

Again referring to Fig. 2, cut-outs 38 are made in the outer contour of the tie rods transverse to the longitudinal direction in a corner area 37 towards cylinder tube 1 between the legs 13, 13', 14 and 14' and the crossbars 15, 15' at right angles to each other. These cut-outs 38 have a longitudinal direction which is parallel to the longitudinal direction of the tie rods or coincides with it.

The contour of each cut-out 38 corresponds to the inner contour of a half of a longitudi nally slotted hollow cylinder and is made as an arc of a circle. Fitting the support brackets 11, 12 to the cylinder tube 1 causes the contact surfaces 21, 21' to make contact with the corresponding parts 22, 22' of the cylinder tube and on the other hand the cut-outs 38 make contact with the tie rods 5 and partly surround these. Screwing the two support brackets together with the connecting parts 29 produces a clamping connection between the support brackets and the cylinder tube and on the other hand secures them against turning due to the combined effect of the cut-outs 38 and the tie rods 5.

For the additional centring of the support 6 relative to the tie rods 5, centring elements 39 such as threaded pins are provided in the legs of the support brackets. The centring elements are provided with threads so that they can be screwed in and out of the openings 40, e.g. bores, going through the legs of the support brackets. The arrangement of the centring elements 39 is such that their longitudinal axis 41 is best situated at a right angle to the axis 28 and also to the longitudinal axis of cylinder tube 1. Two centring elements 39, 39' are provided per leg 13, 13', 14 and 14', which act together with the tie rod situated in the corner area of the leg and the associated crossbar.

According to Fig. 2, the position of the centring elements 39 relative to the associated tie rod 5 is such that the longitudinal axis 41 is displaced by a certain amount from the longitudinal axis of the tie rod 5, where the distance corresponds approximately to the radius of tie rod 5. It is best to make the distance a little larger than this. The ends 42 of the centring elements 39 towards the tie rods are conical and acute, so that a conical shape is obtained. If the centring elements 39 are screwed from the outside 34, 34' towards the cylinder tube 1, this gives contact of surface 43 of the conical ends 42 to areas of the outside circumference 44 of the appropriate tie rod 5. Further screwing produces tensioning of the centring elements to the tie rods, so that these are pressed into the cut-outs 38 accommodating them.This action produces additional centring of the support relative to the working cylinder.

According to Fig. 2, each tie rod 5 has two centring elements 39, 39' assigned to it, which are situated one after the other in the longitudinal direction of cylinder tube 1. The longitudinal axes 41 are at right angles to the longitudinal axes of the positioning elements 33 and are at the same distance from the connecting parts 29 as the positioning elements 33. In order to fit support 6 to cylinder tube 1, the centring elements 39 are first screwed back, so that the tie rods 5 can be inserted in the appropriate cut-outs 38. The two support brackets 11, 12 are now fitted to the cylinder tube and are screwed together using connecting parts 29. The positioning elements 33 are used for positioning. Finally the centring elements 39 are screwed to the tie rods 5 and tightened.

Support 6 is now centred on cylinder tube 1 and on tie rod 5. Support 6 can easily be positioned anywhere along the tie rods or the cylinder tube. The tightened connections between the centring elements 39 and the tie rods 5 are slightly loosened for this purpose and so is the connection between the two support brackets 11 and 12. The support is now movable on the working cylinder and can be pushed to the required position in the longitudinal direction of cylinder tube 1. It is tightened and centred there as described above.

The positioning of the support is particularly simple, if there is no clamped connection between the support brackets 11, 12 and the cylinder tube 1. The support brackets 11, 12 are solidly connected together and are only held in position by the combined action of the centring elements and tie rods. To move the support 6, only the centring elements have to be loosened and it is then possible to move support 6. In particular it is also possible to use support 6 as a so-called 'central flange', which is positioned in the area of the longitudinal centre of the working cylinder or the cylinder tube. The working cylinder can now move around its longitudinal centre, which is required for certain special applications and for where there is only limited space available.

Claims

1. A pneumatic or hydraulic assembly comprising a cylinder guiding a piston, a bearing support comprising two support brackets cooperable with respective parts of the external surface of the cylinder, the brackets being rigidly but releasably connectible to each other and being adapted to be rigidly clamped to the cylinder, each support bracket having a pivot arranged to be rotatably supported in a bearing with the bearing support surrounding the cylinder.

2. An assembly according to claim 1, wherein the support brackets are U-shaped, and each can be located with the open part of the U on the cylinder, with both legs wholly or partly surrounding the cylinder.

3. An assembly according to claim 2, wherein the free ends of the legs of the U of the support brackets are adjacent to each other when located on the cylinder.

4. An assembly according to claim 3, wherein the legs of the U of both support brackets are adjacent on front sides and the two support brackets in the fitted state form a structure which coaxially surrounds the cylinder.

5. An assembly according to any of claims 2 to 4, wherein the spacing between the two legs of each U-shaped support bracket corresponds at least to the outside diameter of the cylinder.

6. An assembly according to claim 5, wherein raised contact surfaces are provided on the insides of the legs for contact with cylinder radially relative thereto, the spacing between two contact surfaces of each support bracket corresponding at least to the outside diameter of the cylinder.

7. An assembly according to any of claims 2 to 6, wherein a base of each U-shaped support bracket is provided with a contact surface which can make contact with the outer circumference of the cylinder on the inside in the direction of the cylinder.

8. An assembly according to claim 7, wherein each of the support brackets are shaped in an arc of a circle at the contact surface, according to the outside contour of the cylinder.

9. An assembly according to claim 7 or 8, wherein the pivots are mounted on the bases of the respective U-shaped support brackets.

10. An assembly according to any of the preceding claims, wherein each pivot is rigidly mounted or shaped on side surfaces of the respective support bracket in a direction away from the cylinder.

11. An assembly according to claim 10, wherein the pivots project from the respective support brackets in opposite directions.

12. An assembly according to claim 10 or 11, wherein the pivots have a common axis of rotation.

13. An assembly according to claim 12, wherein the cylinder has a circular cross section, the pivots projecting radically in the direction away from the cylinder, and the common axis of rotation passing through the centre of the cylinder.

14. An assembly according to any of the preceding claims, wherein the two support brackets are connectible by connecting members.

15. An assembly according to claim 14, wherein the support brackets are U-shaped, and each can be located with the open part of the U on the cylinder, with both legs wholly or partly surrounding the cylinder; and wherein there are penetrations in the two legs of at least one of the support brackets which penetrations are used to accommodate the connecting members.

16. An assembly according to claim 15, wherein threaded openings are provided in the two legs of at least the other of the support brackets, which openings are coaxial with the penetrations and are used to accommodate the ends of the connecting members.

17. An assembly according to claim 16, wherein the longitudinal directions of the penetrations or the openings coincide with the longitudinal direction of the legs of the support brackets.

18. An assembly according to any of claims 14 to 17, wherein the support brackets can be fixed to the cylinder by the connecting members and the contact surfaces of the support brackets are in contact with parts of the outside circumference of the cylinder.

19. An assembly according to any of the preceding claims, wherein the support contains positioning elements which are used to fix the support brackets rigidly to each other.

20. An assembly according to claim 19, wherein the support brackets are U-shaped, and each can be located with the open part of the U on the cylinder, with both legs wholly or partly surrounding the cylinder; and wherein the positioning elements can be fitted in positioning cut-outs in the front sides of legs of the support brackets.

21. An assembly according to claim 19 or 20, when dependent on any of claims 14 to 18, wherein the longitudinal axis of the positioning elements is parallel to the longitudinal axis of the connection members.

22. An assembly according to claim 20 or 21, wherein a single positioning element is provided to secure the position of two legs relative to each other.

23. An assembly according to any of the preceding claims, wherein at least one barshaped tie rod is provided in the area of the outside circumference of the cylinder, and cooperates with the support.

24. An assembly according to claim 23, wherein the longitudinal axis of the or each tie rod is parallel to the longitudinal axis of the cylinder.

25. An assembly according to claim 23 or 24, wherein the tie rods are fixed in the area of the axial ends of the cylinder.

26. An assembly according to any of claims 23 to 25, wherein there are provided four tie rods which are distributed equally over the outside circumference of the cylinder, and which run at a radial distance from the circumference of the cylinder and parallel to its longitudinal axis.

27. An assembly according to any of claims 23 to 26, wherein the or each tie rod has a circular cross section.

28. An assembly according to any of claims 23 to 27, wherein the support has a cut-out corresponding to the outer contour of the or each tie rod, and which, when the support is fitted to the cylinder, fits the tie rod.

29. An assembly according to claim 28, wherein the support brackets are U-shaped, and each can be located with the open part of the U on the cylinder, with both legs wholly or partly surrounding the cylinder; and wherein a plurality of the cut-outs are made in the corner areas in the direction of the cylinder tube of the transition from the legs of the support brackets to the bases carrying the pivots.

30. An assembly according to claim 29, wherein the contour of the cut-outs corresponds to the inside contour of a longitudi nally slotted or half of a longitudinally slotted hollow cylinder.

31. An assembly according to any of claims 23 to 30, wherein the support contains centring elements by which the support can be centred relative to the tie rods.

32. An assembly according to claim 31, wherein the centring elements are made as threaded pins and can locate in respective openings in the support brackets.

33. An assembly according to claim 31 or 32, wherein the centring elements each have a conical, acute end.

34. An assembly according to any of claims 31 to 33, wherein the centring elements extend substantially at right angles to the longitudinal axis of the tie rods.

35. An assembly according to claim 34, wherein the centring elements are situated in the legs of the support brackets.

36. An assembly according to any of claims 31 to 35, wherein each tie rod has at least one centring element assigned thereto.

37. An assembly according to claim 36, wherein two centring elements are assigned to each tie rod, and are located one after the other relative to the longitudinal direction of the cylinder.

38. An assembly according to claim 36 or 37, wherein the longitudinal axes of the centring elements are at right angles to the respective tie rods and are spaced by a distance corresponding to the radius of the tie rod from the longitudinal axis of the tie rod.

39. An assembly according to claim 38, wherein the longitudinal axes of the centring elements are displaced in the direction of the free ends of the legs of the support brackets relative to the tie rods.

40. An assembly according to any of claims 31 to 39, wherein the surface of the conical end areas of each of the centring elements can be tightened up by moving the centring element in the direction of the respective tie rod relative to its outside diameter.

41. An assembly according to any of claims 31 to 40, wherein the support can be centred on the cylinder, on the one hand by its contact surfaces and on the other hand by the combined effect of the centring elements and the tie rods.

42. An assembly according to any of the preceding claims, wherein the support can be selectively positioned along the longitudinal di rection of the cylinder.

43. A pneumatic or hydraulic assembly substantially as hereinbefore described with reference to the accompanying drawings.