WO2003087586A1

WO2003087586A1 - A device for producing a linear movement

Info

Publication number: WO2003087586A1
Application number: PCT/SE2003/000598
Authority: WO
Inventors: Leif Börje JOHANNESSON
Original assignee: Delaval Holding Ab
Priority date: 2002-04-17
Filing date: 2003-04-14
Publication date: 2003-10-23
Also published as: AU2003225455A1; SE0201155D0; SE0201155L; SE521964C2

Abstract

The invention refers to a device for producing a linear movement, and to a removing device. The device includes a cylinder (1) forming a cylinder space and a piston, movable in the cylinder and dividing the cylinder space into a first space and a second space. A piston rod (5) is connected to the piston and extends out of the cylinder. A closing body (6) arranged at one end of the cylinder to form a closed space of one of the first and second spaces, wherein the closed space is intended to contain a medium. A first passage permits the medium to flow to the closed space. A second passage permits the medium to flow from the closed space. Control means controls the flow of the medium to and from the closed space via the passages. A separate element (30) includes the closure member, the control means and the passages.

Description

A device for producing a linear movement

THE BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention refers to a device for producing a linear movement, including a cylinder forming a cylinder space, a piston movable in the cylinder and dividing the cylinder space into a first space and a second space, a piston rod, connected to the piston and extending out of the cylinder, a closure member arranged at one end of the cylinder to form a closed space of one of the first space and the second space, wherein the closed space is intended to contain a medium, at least a first passage for permitting the medium to flow to the closed space, at least a second passage for permitting the medium to flow from the closed space, and control means for controlling the flow of the medium to and from the closed space via the passages.

The invention also refers to a removing device for retracting a milking member including at least one teatcup from a teat of an animal.

Such devices are used for various purposes. For instance, such devices are frequently used in a removing device for retracting the milking member and the teatcups from the teats of a dairy animal when the milking of the animal is to be finished. The device can be designed in such a manner that the movement of the piston in the cylinder is obtained by the application of a vacuum to the closed space or the application of a pressurised medium to the closed space. A disadvantage of such devices is that they consists of a number of different standard components which are mounted to each other by* means of various joining member and connecting conduits. The total costs for such devices are therefore relatively high, i.e. the costs for the high number of standard components and the costs for the mounting of the device.

US-A-3,991 ,716 discloses a milking plant having such a device for providing a linear movement for retracting the milking member and the teatcups from the teats of an animal. The device includes a cylinder housing a piston, which via a piston rod and a rope is connected to the milking member. The cylinder is driven by the supply of a medium under high pressure, i.e. pressurised air. The supply of pressurised air is controlled by means of a control valve arrangement provided at a distance from the cylinder and connected to the cylinder via separate conduits.

SE-B-340 911 discloses another milking plant having such a device for providing a linear movement for retracting the milking member and the teatcups from the teats of an animal. The device includes a cylinder housing a piston, which via a piston rod and a rope is connected to the milking member. In this prior art device, the cylinder is driven by the application of vacuum or low pressure. The application of the vacuum is controlled by means of a control valve arrangement provided at a distance from the cylinder and connected to the cylinder via separate conduits.

SUMMARY OF THE INVENTION

The object of the present invention is overcome the disadvantage mentioned above and to provide a simplified and less expensive device for providing a linear movement.

This object is achieved by means of the device initially defined, wherein the device includes a separate element, which includes the closure member, the control means and the passages. Such a separate element may thus be designed to include a plurality of the components, which are essential for the operation and function of the device, i.e. for providing the linear movement of the piston in the cylinder. Such an element may be manufactured as a separate element, which is the substantially only additional element except for the cylinder and the piston need to complete the device. Advantageously, said separate element forms a single body. Such a single body can be compact and is easy to handle in case of replacement, and in case of service and repair of the device. Said body may then be attachable to and detachable from the cylinder as an integrated unit. Consequently, the device may consist substantially of a first separate module including the cylinder and the piston and a second separate module including said body.

According to an embodiment of the invention, the control means includes a first valve member arranged to take one position of a first position, in which the first passage is open and the second passage is closed, and a second position, in which the first passage is closed and the second passage is open. By means of such a first valve member, included in the separate element, the closed space can be connected either to the surroundings or to a low-pressure source or a high-pressure source.

According to a further embodiment of the invention, the control means includes a flow-reducing member for throttling the flow through one of the passages. By means of such a flow-reducing member, included in the separate element, the speed of the movement of the piston may be adjusted to a desired level. Advantageously, the first valve member is arranged between the closed space and the flow-reducing member.

According to a further embodiment of the invention, the control means includes a second valve member provided to take one position of an open position and a closed position with regard to one of the passages. By means of such a second valve member, included in the separate element, the movement of the piston may thus be initiated. Advantageously, the flow-reducing member may be arranged between the first valve member and the second valve member. Furthermore, the second valve member may include an electromagnet for adjusting the second valve member to take one of the open and closed positions.

According to further embodiment of the invention, said separate element includes an opening permitting the passage of the piston rod. Such an embodiment is very compact since all parts are included in the separate element. Preferably, a seal member is arranged at the opening to abut the circumferential surface of the piston rod. In such an embodiment, the separate element may also include at least one attachment member for permitting attachment to any structure of an arrangement where the device is to be used. The separate element will thus carry a main part of the weight of the device and the load produced by the device during the work of the piston.

According to a further embodiment of the invention, the first passage is connectable to a source providing a relatively high pressure of the medium in the closed space, and wherein the second passage is connectable to the surroundings. By means of such a design pressurised air may thus be employed to move the piston in the cylinder. In this connection, the second valve member may control the first valve member to be in the first position when the second valve member is in the open position and to be in the second position when the second valve member is in the closed position.

According to a further embodiment of the invention, the second passage is connectable to a vacuum pump providing a relatively low pressure of the medium in the closed space, and wherein the first passage is connectable to the surroundings. By means of such a design, a vacuum or low pressure may thus be employed to suck the medium out of the closed space and move the piston in the cylinder. In this connection, the second valve member may control the first valve member to be in the second position when the second valve member is in the open position and to be in the first position when the second valve member is in the closed position. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described more closely by means of various embodiments thereof and with reference to the drawings attached hereto.

Fig 1 discloses a principle diagram of a device according to a first embodiment of the invention, wherein the function of the different elements of the device is disclosed and wherein the device is connected to a high-pressure source.

Fig 2 discloses a perspective view of the device in Fig 1.

Fig 3 discloses a perspective exploded view of the device in Fig 2.

Fig 4 discloses a perspective exploded view of a separate element of the device in Fig 2 from a first direction. Fig 5 discloses a perspective exploded view of the element I Fig 4 from a second direction.

Fig 6 discloses schematically a view of a milking plant including the device in Fig 2.

Fig 7 discloses a principle diagram of a device according to a second embodiment of the invention, wherein the function of the different elements of the device is disclosed and wherein the device is connected to a vacuum pump.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION

Fig 1 discloses principle diagram of a device for producing a linear movement. The device includes a cylinder 1 forming an inner cylinder space and a piston 2, which is movable in the inner cylinder space. The piston 2 divides the cylinder space into a first space 3 below the piston 2 in Fig 1 , and a second space 4. A piston rod 5 is connected to the piston 2. A closure member 6 is arranged at one end of the cylinder 1 to form a closed space of the first space 3 in the embodiment disclosed in Fig 1. The piston rod 5 extends out of the cylinder 1 to the surroundings through the first space 3 and the closure member 6. The second space 4 is open to the surroundings. A filter 8 is arranged on top op the cylinder 1 for preventing dirt or other particles from reaching the inner cylinder space of the cylinder 1.

In the embodiment disclosed in Fig 1 , the closed space is intended to contain a medium in the form of pressurised air, wherein the pressure will exert a force to the piston 2 for moving the piston 2 upwardly in Fig 1. The pressurised air is supplied from a high-pressure source 9, for instance in the form of a compressor producing a pressure significantly above the atmospheric pressure. The pressurised air is transported from the high-pressure source 9 to the first space 3 via an air conduit 10 and a first passage 11. In order to permit the piston 2 to move downwardly in Fig. 1 , the pressurised air can flow from the first space 3 to the surroundings via a second passage 12.

The first passage 11 is formed of a common conduit 15, a first valve member 16, an intermediate conduit 17, a second valve member 18 and an inlet nipple 19 connected to the air conduit 10. The intermediate conduit 17 includes a flow-reducing member 20, which is arranged between the first valve member 16 and the second valve member 18 for throttling the flow through the first passage 11.

The second passage 12 is formed of the common conduit 15, the first valve member 16 and an outlet conduit 21.

The common conduit 15, the first valve member 16, the intermediate conduit 17 with the flow-reducing member 20, and the second valve member 18 thus forms control means for controlling the flow of the medium to and from the closed first space 3 via the passages 11 , 12.

The first valve member 16 is arranged to take one position of a first position, in which the first passage 11 is open and the second passage 12 is closed, and a second position, in which the first passage 11 is closed and the second passage 12 is open. In the embodiment disclosed, the first valve member 16 includes a valve body 25 arranged in a valve space 26 to which the common conduit 15, the intermediate conduit 17 and the outlet conduit 21 are connected. The valve body 25 is thus movable between the first position, in which the common conduit 15 and the outlet conduit 21 communicate via the valve space 26, whereas the intermediate conduit 17 is closed, and a second position, in which the common conduit 15 and the intermediate conduit 17 communicate, whereas the outlet conduit 21 is closed.

The second valve member 18 is arranged to take one position of an open position and a closed position with regard to the first passage 11. The second valve member 18 includes an electromagnet 27 for adjusting the second valve member 18 to take one of the open and closed positions. The second valve member 18 may, via the electromagnet 27, be connected to a control unit (not disclosed) for activating and deactivating the device and the movement of the piston. In the open position, pressurised air from the high-pressure source will flow through second valve member 18 and the intermediate conduit 17 into the valve space 26 and move the valve piston 25 to the second position. The pressurised air will thus flow into the closed first space 3 and move the piston 2 upwardly in Fig 1. In the closed position, there is no flow of pressurised air from the high-pressure source 9. The valve body will then move to the second position permitting the pressurised air to escape from the first space 3 and the piston to move downwardly in Fig 1. The second valve member 18 thus controls the first valve member 16 to be in the first position when the second valve member 18 is in the open position and to be in the second position when the second valve member 18 is in the closed position.

As appears from Figs 2 - 5 the device includes a separate element 30, which includes the closure member 6, the control means 16, 20, 18 and the passages 11 , 12. The separate element 30 is designed to form a single body including three main parts 31 , 32, 33. The first part 31 includes the closure member 6 and the common conduit 15. The second part 32 includes the first valve member 16, the intermediate conduit 17 with the flow-reducing member 20, the second valve member 18, the inlet nipple 19, and the outlet conduit extending out through the bottom surface of the second part 32 and thus not disclosed in Fig3 2-5. The third part 33 includes the electromagnet 27. The three parts 31, 32, 33 of the separate element 30 are attached to each other to form a single body by means of screw connections 34 and 35, schematically indicated. The first part 31 abuts tightly and is firmly attached to the second part 32 by means of the screw connections 34. The second part 32 abuts tightly and is firmly attached to the third part 33 by means of the screw connection 35. The separate element 30 is thus attachable to and detachable from the cylinder 1 as an integrated unit.

Furthermore, the first part 31 of the separate element 30 includes an opening 36 permitting the passage of the piston rod 5. A seal member 37 is provided at the opening 36 for abutting sealingly the circumferential surface of the piston rod 4 in order to prevent air leakage from the first space 3 to the surroundings.

The separate element 30 may also include an attachment member 38 for permitting attachment to any structure of the arrangement where the device is to be used. In the embodiment disclosed, the attachment member 38 is attached to the lower side of the first part 31 of the separate element 30. The attachment member 38 includes two attachment flanges extending outwardly. The total weight of the device and the load produced by the device will thus be carried by the attachment member 38. It is also possible to provide a further attachment member 39 at the top of the cylinder 1 for attachment to said structure. In the embodiment disclosed in Fig 2, the upper attachment member 39 is also arranged to hold the filter 8.

Fig 6 discloses schematically a milking arrangement 50 including a milking box 51 and a milking machine with a long milk conduit 52 and a milking member including a claw 53 and four teatcups 54 to be applied to an animal to be milked. The arrangement 50 also includes a removing device 55 for retracting the teatcups 54 and the milking member from the teats of the animal. The removing device 55 includes a device as described above and a elongated flexible element 56 connecting the milking member 53 to the piston rod 5 of the device. The flexible element 56 may be formed by a cord or a chain, for instance. It is to be noted that the removing device 55 may also be used to retract a single teatcup in case the teats are milked separately from each other without the use of a collecting claw.

Fig 7 discloses a principle diagram of a second embodiment of the device, which differs from the device of the first embodiment in that the movement of the piston is driven by a low pressure or vacuum in the closed space instead of by a high pressure. In the second embodiment, the first passage 11 , permitting a flow of the medium to the first space 3, is thus connectable to the surroundings, whereas the second passage 12, permitting a flow of the medium from the first space 3, is connected to a vacuum pump 60 sucking the medium from the first space 3 for providing a relatively low pressure therein. In this embodiment, the first passage 11 is formed of a common conduit 15, a first valve member 16 and an inlet conduit 21. The second passage 12 is formed of the common conduit 15, the first valve member 16, an intermediate conduit 17, a second valve member 18 and an outlet nipple 19 connected to the vacuum pump 60 via an air conduit 10. The intermediate conduit 17 includes a flow-reducing member 20, which is arranged between the first valve member 16 and the second valve member 18 for throttling the flow through the second passage 12. Also in this embodiment, the first valve member 16, schematically disclosed, is controlled by the position of the second valve member 18 in such a manner that the first valve member 16 is in the second position when the second valve member 18 is in the open position and in the first position when the second valve member 18 is in the closed position.

In the second embodiment disclosed in Fig 7, the closure member 6, and thus the separate element 30 (not disclosed in Fig 7), is arranged on top of the cylinder to form a closed space of the second space 4.

The present invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claims. It is to be noted that the separate element 30 does not need to include all the control means described above. In a first aspect of the invention, the separate element 30 may include only the first valve member 16. In second aspect of the invention the separate element may include the first valve member 16 and the flow-reducing member 20. In a third aspect of the invention, the separate element 30 may include the first valve member 16, the flow-reducing member 20 and the second valve member 18.

The device disclosed in the embodiments is arranged to exert a pulling force with regard to the piston rod 5. It is to be noted that the device may also be arranged to exert a pushing force with regard to the piston rod. In the first embodiment, the second space 4 will then form the closed space, and in the second embodiment the first space 3 will form the closed space.

Claims

1. A device for producing a linear movement, including a cylinder (1) forming a cylinder space, a piston (2) movable in the cylinder (1) and dividing the cylinder space into a first space (3) and a second space (4), a piston rod (5), connected to the piston (2) and extending out of the cylinder (1 ), a closure member (6) arranged at one end of the cylinder (1 ) to form a closed space of one of the first space (3) and the second space (4), wherein the closed space is intended to contain a medium, at least a first passage (11) for permitting the medium to flow to the closed space, at least a second passage (12) for permitting the medium to flow from the closed space, and control means (16, 18, 20) for controlling the flow of the medium to and from the closed space via the passages (11, 12), wherein the device includes a separate element (30), which includes the closure member (6), the control means (16, 18, 20) and the passages (11 , 12).

2. A device according to claim 1 , wherein said separate element (30) forms a single body.

3. A device according to any one of claim 1 and 2, wherein said separate element (30) is attachable to and detachable from the cylinder (1) as an integrated unit.

4. A device according to any one of the preceding claims, wherein the control means includes a first valve member (16) arranged to take one position of a first position, in which the first passage (11) is open and the second passage (12) is closed, and a second position, in which the first passage (11 ) is closed and the second passage (12) is open.

5. A device according to any one of the preceding claims, wherein the control means includes a flow-reducing member (20) for throttling the flow through one of the passages (11 , 12).

6. A device according to claim 5, wherein the first valve member (16) is arranged between the closed space and the flow-reducing member (20).

7. A device according to any one the preceding claims, wherein the control means includes a second valve member (18) provided to take one position of an open position and a closed position with regard to one of the passages (11 , 12).

8. A device according to claim 7, wherein the flow-reducing member (20) is arranged between the first valve member (16) and the second valve member (18).

9. A device according to any one of claims 7 and 8, wherein the second valve member (18) includes an electromagnet (27) for adjusting the second valve member (18) to take one of the open and closed positions.

10. A device according to any one the preceding claims, wherein said separate element (30) includes an opening (36) permitting the passage of the piston rod (5).

11. A device according to any one of the preceding claims, wherein a seal member (37) is arranged at the opening (36) to abut the circumferential surface of the piston rod (5).

12. A device according to any one of the preceding claims, wherein said separate element (30) includes at least one attachment member (38) for permitting attachment to any structure of an arrangement where the device is to be used.

13. A device according to any one of the preceding claims, wherein the first passage (11 ) is connectable to a source (9) providing a relatively high pressure of the medium in the closed space, and wherein the second passage (12) is connectable to the surroundings.

14. A device according to claims 4, 7 and 13, wherein the second valve member (18) controls the first valve member (16) to be in the first position when the second valve member (18) is in the open position and to be in the second position when the second valve member (18) is in the closed position.

15. A device according to any one of claims 1 to 12, wherein the second passage (12) is connectable to a vacuum pump (60) providing a relatively low pressure of the medium in the closed space, and wherein the first passage (11 ) is connectable to the surroundings.

16. A device according to claims 4, 7 and 15, wherein the second valve member (18) controls the first valve member (16) to be in the second position when the second valve member (18) is in the open position and to be in the first position when the second valve member (18) is in the closed position.

17. A removing device for retracting a milking member including at least one teatcup (54) from a teat of an animal, wherein the removing device (55) includes a device according to any one of claims 1-16.