CA1206840A

CA1206840A - Fluid drive means for a reciprocating motion

Info

Publication number: CA1206840A
Application number: CA000417268A
Authority: CA
Inventors: Goran Egelius; Christer Ericson
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-12-08
Filing date: 1982-12-08
Publication date: 1986-07-02
Also published as: SE428235B; GB2123088B; GB2123088A; IT1157130B; WO1983002135A1; GB8320007D0; JPS58502160A; ES8401197A1; FR2517762A1; DE3249254T1; ES518005A0; IT8268441A0; SE8107338L; FR2517762B1; IT8254040V0

Abstract

Abstract Of The Disclosure A fluid drive means for a linear reciprocating motion is provided with at least one flexible and collapsible member (15) arranged between elements (11, 12, 14) which move in relation to each other during operation. The member (15) surrounds between said elements (11, 12, 14) a central rod (13), which extends through one of the elements (11, 12). Together with the rod the member (15) completely delimits a fluid chamber for the pressure fluid which is required for the operation of the drive means. The member (15) which is made for instance of an elastomer constist of a roll-membrane and establishes a sealing (19) around the rod (13).

Description

6 !340 DESCRIPTION
The present invention concerns a hydraulic or pneumatic fluid drive means for a reciprocating motion. It is provided with a-t least one flexible and collapsible n~nber arranged between elements which Eve in relation to each other during operation. The chief field of application for such a drive means is as a servo-motor.
A drive means of the above mentioned kind is Cowan for instance through the Swedish layout print No. 7305870-30 There the collapsible member is a bellows which is provided only on the side of the shaft or rod opposite the element or piston in question. Generally such a single-actiny drive means is unsuitable as a serv~-motor, and the ye puns bellows is co-.nplicatea and~q~3iaiY~ to manu~cture. Further it is impossible to make it double-acting with a pressure-member on the other side of the piston. The US Patent No. 2,465,560 issued March 29, 1949 to Warnke, suggests a solution of the sealing problems in a double-acting piston-cylinder-assembly by means of rubber containers or jags in the cylinder chambers.
The object of the invention is to produce in a simple way a reciprocating motion for pneumatic or hydraulic forces without high ZOO demands for machinery accuracy and without the sealing problems that arise when air or another fluid is enclosed in metal cylinders with sealed components. With other words, a cheaper and simpler alternative to conventional piston-cylinder-assemblies for carrying out control mDwements ; is intended.
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According to the invention this problem is solved in that the God in the fluid drive means together with said member completely delimit a fluid chamfer for the pressure fluid which is required for the operation of the drive means and in that said member, which is I
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lZ06~34~1 made or instance ox an elastomers consists of a roll membrane and establishes a sealing against the rod, owe instance a lip sealing. I
The invention will now be sat described with reference to the accompany drawing which in an axial section show an embodiment ox the fluid drive means according to the invention.
In the shown embodiment the fluid drive means comprises a housing or cylinder 10 with end walls lo.
12. In the end walls an output rod 13 is mounted for linear movement. The rod 13 carries a pressure plate 14 between the end walls 11, 12. On each side of the pressure plate 14 a pressure chamber is delimited by a membrane 15, preferably ox rubber, and by the rod 13.
In each end wall a connection 16 for pressure fluid is provided.
t the pressure plate 14 the membrane 15 it statically sealed against the rod 13. A rink may for instance press a flange 19 ox the membrane against the row 13. At the end walls the membrane 15 is dynamically sealed against the rod 13 by means ox a conventional sealing 20, for instant e a lip sealing, made in one piece with the membrane 15. Of manufacturing and assembling reasons the side 21 of the membrane bearing ~25 on the end walls 11 and 12 respectively is manufactured separately and connected to the main part ox the membrane.
When pressure fluid is removed from the pressure chamber on one side angled to the pressure chamber on the other Saudis that the pressure plate 14 and wit that the rod 13 moves in one direction the membrane 15 is collapsed in such a without it rolls up like a roll membrane with one layer outside the other. In order to control this movement a part 22 of the membrane nearest the pressure plate 14 has been made thicker. In that way an indication of bending comes us where this part 22 I, ., . :

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ends. If for instance this part 22 is made a little longer than a third of the axial length ox the membrane eke latter will form three layers when it is collapsed.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A fluid drive means for a reciprocating motion and provided with at least one flexible and collapsible member (15) arranged between elements (11, 12, 14) which move in relation to each other during operation, said member (15) between said elements (11, 12, 14) surrounding a central rod (13) which extends through one of the elements (11, 12), comprising at least one fluid chamber for the pressure fluid which is required for the operation of the drive means being situated between two of the elements and partially delimited by said member, said member being made for instance of an elastomer and comprising a roll membrane having a controlled rolling originating at a specified location, a dynamic sealing (20) for instance a lip sealing being established around the rod (13), where it extends through said one of the elements, the rod being statically sealed by said member of its connection with another of said elements.

2. A fluid drive means according to claim 1 wherein said roll membrane (15) has a change in thickness at, said specific location.

3. A fluid drive means according to claim 2, character-ized in that said thicker part (22) extends through a little more than a third of the axial length of the membrane (15) so that the membrane (15) will form three layers when it is collapsed.

4. A fluid drive means according to any of claims 1-3, characterized in that such a member (15) is provided on each side of a plate (14) secured to said rod (13), which plate (14) together with end walls (11, 12) of a cylinder (10) for each member form a pair of said elements, fluid connections (10) being provided in the end walls (11, 12).

5. A fluid drive means according to claim 1 wherein said membrane has a top wall which is thicker than the side walls of said membrane so that when the pressure fluid is applied during the operation of the drive means a passage way is defined between the external surfaces of the side walls and the internal surface of the fluid chamber to permit the passage of a fluid such as a lubricating fluid for said membrane.

6. A fluid drive means according to claim 1 wherein said membrane has a top wall which is movable and is part of the rolling process.

7. A fluid drive means according to claim 1 wherein said membrane forms an S-shaped roll.

8. A fluid drive means accroding to claim 1 wherein the controlled rolling of said membrane originates only at said specific location.

9. A fluid drive means according to claim 1 wherein the controlled rolling originates at said specific location due to the variation in wall thickness of said membrane at said specific location.

10. A fluid drive means according to claim 1 where said member partially covers the axial length of said central rod.