THREE-POSITION PNEUMATIC OR HYDRAULIC POWER CYLINDER

Abstract

The invention relates to hydraulic cylinder devices and can be used in vehicle transmissions. A three-position pneumatic or hydraulic cylinder consists of a housing having end caps, two pistons, a rod, and supply channels for a working fluid, each piston being configured for limited movement along the rod as a result of a central protuberance, which separates the pistons, and peripheral protuberances on the rod, and being configured for limited movement inside the housing. The central protuberance is configured in the form of a bushing, and an annular protuberance is, configured on the inside surface of the housing. Said bushing and said protuberance form a hermetic moveable coupling of the shaft/opening type. Separate channels are provided for supplying working fluid to the chambers formed by each piston and the corresponding end of the housing, and a shared channel is provided for supplying working fluid to the chambers formed by each piston and the central protuberance and bushing; or, separate channels are provided for supplying working fluid to the chambers formed by each piston and the central protuberance and bushing, and a shared channel is provided for supplying working fluid to the chambers formed by each piston and the corresponding end of the housing.

Claims

1. A three-position pneumatic or hydraulic cylinder consisting of a housing having end caps, two pistons, a rod, and supply channels for a working fluid, each piston being configured for limited movement along the rod as a result of a central protuberance, which separates the pistons, and peripheral protuberances on the rod, and being configured for limited movement inside the housing wherein the central protuberance is configured in the form of a bushing, and an annular protuberance is configured on the inside surface of the housing wherein the bushing and protuberance form a hermetic moveable coupling of the shaft/opening type.

2. A three-position cylinder according to claim 1 wherein the working fluid supply channels are implemented as follows: separate channels to the chambers formed by each piston and the corresponding end of the housing, and a shared channel to the chambers formed by each piston and the central protuberance and bushing.

3. A three-position cylinder according to claim 1 wherein the working fluid supply channels are implemented as follows: separate channels to the chambers formed by each piston and the central protuberance and bushing, and a shared channel to the chambers formed by each piston and the corresponding end of the housing.

4. A three-position cylinder according to claim 1, wherein at least one load interacting pin inclined to the rod axis is located in the bore of the annular protuberance.

5. A three-position cylinder according to claim 2, wherein at least one load interacting pin inclined to the rod axis is located in the bore of the annular protuberance.

6. A three-position cylinder according to claim 3, wherein at least one load interacting pin inclined to the rod axis is located in the bore of the annular protuberance.

Description

[0023] The invention is illustrated by graphic materials: a prototype drawings and photographs.

[0024] FIG. 1 shows a longitudinal sectional view of a first preferred embodiment of a cylinder, central (middle) position.

[0025] FIG. 2 shows a longitudinal sectional view of a first preferred embodiment of a cylinder, rightmost position.

[0026] FIGS. 3 and 4 show a longitudinal sectional view of a second preferred embodiment of a cylinder, the central (middle) position with different design of the working fluid supply channels.

[0027] FIG. 5 shows a longitudinal sectional view of a second preferred embodiment of a cylinder, rightmost position.

[0028] FIG. 6 shows a general view of a prototype three-position cylinder with two end rod elements.

[0029] FIG. 7 shows an exploded view of a prototype three-position cylinder with two end rod elements.

[0030] FIG. 8 shows an exploded view of a prototype three-position cylinder with one end rod element.

[0031] A three-position cylinder consists of a housing 1 where the rod is located including the central part that a cylindrical bushing 2 with two protuberances for pistons 3 and 4 having free play both inside the cylindrical part of the housing 1 and on the bushing 2, two end caps 5 and 6, end rod elements 7, 8 and side pin 9. Preferably, the rod consists of several rigidly connected parts: bushing 2 made of a low friction sliding material, end parts 7, 8 with peripheral protuberances and side pin 9. The device also comprises working fluid (compressed air or liquid) supply channels A, B and C.

[0032] In the first preferred embodiment (FIGS. 1 and 2), separate channels A and C to the chambers formed by each of the pistons 3, 4 and the corresponding end of the housing (caps 5 and 6) can be provided in the housing and caps 5 and 6. The shared channel B to the chambers formed by each of the pistons 3, 4 and the central protuberance and bushing 2 can be provided in the protuberance of the housing 1.

[0033] In the second preferred embodiment (FIGS. 3, 4, 5), separate channels A and C to the chambers formed by each of the pistons and the central protuberance and bushing, is provided in the protuberance of the housing 1, and the shared channel B to the chambers formed by each of the pistons 3, 4 and the corresponding end (end caps 5, 6) can be provided in the wall of the housing 1 (FIGS. 3 and 5), or in the bushing 2 (FIG. 4).

[0034] The device is operable with any number of output load interacting elements (end elements 7, 8, pin 9). When using the device without end element(s) 7, 8, a protruding piston stroke limiter (pistons 3, 4) shall be installed on the bushing 2 and cap (caps 5, 6) with no rod holes. A prototype device with one end rod element is shown in FIG. 8.

[0035] The device operation according to the first preferred embodiment (compressed air) is as follows.

[0036] When compressed air is supplied to channel B, piston 3 moves to the left, and piston 4 moves to the right, the pistons reach the protuberances of the caps 5, 6 and rest against the retaining protuberances of the rods 7 and 8 to, set the bushing 2 in the middle position (FIG. 1). Channels A and C are open to the atmosphere at that moment.

[0037] When compressed air is supplied to channel A, piston 3 moves to the right and, having reached the protuberance of the bushing 2, pushes it to the right, then the piston 3 rests against the retaining protuberance of the main housing, and the bushing 2 rests against the piston 4 that rests against the cap 6, thereby the bushing 2 with elements 7, 8 and pin 9 is set to the rightmost position (FIG. 2). Channels B and C are open to the atmosphere at that moment.

[0038] Movement to the leftmost position is made in the opposite (mirror) order relative to the movement to the rightmost position.

[0039] If the main housing, protuberances of end caps 5, 6 and bushing 2 have asymmetrical design, the rod may be retained in the required (shifted) intermediate position relative to the central (middle) position.

[0040] The device operation according to the second preferred embodiment (compressed air) is as follows (FIGS. 3, 4).

[0041] The device is also operable with any number of output load interacting elements (end elements 7, 8, pin 9). When using the device without end element(s) 7, 8, a protruding piston stroke limiter (pistons 3, 4) shall be installed (as in the first preferred embodiment) on the bushing 2 and cap (caps 5, 6) with no rod holes (FIG. 8).

[0042] When compressed air is supplied to channel B, piston 3 moves to the right, and piston 4 moves to the left, the pistons reach the protuberances of the bushing 2 and rest against the housing to set the bushing 2 with rods 7, 8 and pin 9 in the middle position. Channels A and C are open to the atmosphere at that moment.

[0043] When compressed air is supplied to channel C, piston 4 moves to the right and, having reached rod 8, moves the bushing 2 to the right, the rod 7 rests against piston 3, and the bushing 2 with rods 7, 8 and pin 9 is set to the rightmost position. Channels A and B are open to the atmosphere at that moment.

[0044] Movement to the leftmost position is made in the opposite (mirror) order relative to the movement to the rightmost position.

[0045] If the main housing 1 and bushing 2 have asymmetrical design, the rod may be retained in the required (shifted) intermediate position relative to the central (middle) position.

[0046] The operation principle of the device under liquid pressure is similar to the operation with compressed air but the channels of the main liquid lines that are not under high pressure at the rod repositioning shall open to the main low-pressure liquid line and expansion tank.

INDUSTRIAL APPLICABILITY

[0047] The prototype device (without pin 9 FIGS. 6, 7, 8) during testing demonstrated the operational capability, solved the problem and achieved the said technical result.

[0048] No failures, partial engagement and interruptions recorded during trial operation. It should also be noted that when any of three said positions is reached, the rod (and/or pin) driving (moving) force is the same, therefore it is valid to say that the cylinder is a power cylinder if ensured that all three positions are reached. The driving (moving) device is also operable with a to joint tightness but to ensure force retention in the reached position (under the working fluid pressure) appropriate tightness and sealing in the pistons and end caps shall be provided.