GB1596656A

GB1596656A - Fluid operated tool with a valve controlled reversible motor

Info

Publication number: GB1596656A
Application number: GB2726977A
Authority: GB
Original assignee: Compair Industrial Ltd
Current assignee: Compair Industrial Ltd
Priority date: 1978-04-12
Filing date: 1978-04-12
Publication date: 1981-08-26

Description

(54) FLUID OPERATED TOOL WITH A VALVE CONTROLLED REVERSIBLE MOTOR (71) We, COMPAIR INDUSTRIAL LIMITED, a British Company, of PO Box No. 7, Broomwade Works, High Wycombe, Buckinghamshire, HP13 5SF, do hereby declare the invention for which we pray 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 fluid operated tools and more particularly to a fluid operated tool of the kind comprising a reversible fluid-operated motor having two inlets and an outlet for fluid and reversing control means for connecting a fluid inlet of the tool to either one of the motor inlets. Such tools will hereafter be referred to as "of the kind described".

The invention provides a fluid operated tool of the kind described in which the reversing control means comprises a valve including a cylindrical valve member mounted in a housing of the tool in which said valve member is rotatably movable relative to the housing between a first position in which the tool fluid inlet is connected to a first of the motor inlets and a second position in which the tool fluid inlet is connected to the second motor inlet and said valve member is alternatively slidably movable relative to said housing between said first position and a third position in which the tool fluid inlet is connected to the second motor inlet. The motor is preferably of the rotary vane type.

The tool may include a second valve upstream of the first valve, said second valve being operable to connect and disconnect the tool fluid inlet from the first valve.

The second valve may comprise a slide valve member which is mounted in the housing of the tool. An extension of the slide valve member may protrude from the housing and a lever may be provided pivoted on the housing, for moving said slide valve member between open and closed positions, against the action of a spring. Preferably, the valve member of the second valve is adapted to have a button connected thereto for operating the valve instead of the lever. The extension of the slide valve member may be screw threaded for this purpose.

The housing of the tool preferably includes an elongate cylindrical chamber in which the motor is arranged with its axis of rotation parallel to the axis of the chamber.

The first valve is preferably located in a transverse cylindrical bore formed in the housing, said bore including an inlet orifice in communication with the tool fluid inlet and two outlet orifices in communication with the two motor fluid inlets.

The valve member of the first valve preferably includes a first port for connecting the inlet orifice to a first outlet orifice in the first position and to the second outlet orifice in the second position and a second port for connecting the inlet orifice to the second outlet orifice in the third position.

The first valve bore preferably includes a third outlet orifice in communication with an exhaust outlet of the tool and the first valve member preferably includes a third port in communication with said third outlet orifice and connected by a fourth port to a fifth port which is in communication with the second outlet orifice in the first position and with the first outlet orifice in the second position and further connected to a sixth port which is in communication with the first outlet orifice in the third position. This arrangement provides an outlet to exhaust for the scavenge air in all positions.

The first valve member preferably includes a circumferential groove which is engaged by a pin to limit movement between the first and second positions and a longitudinal groove which is alternatively engaged by a pin to limit movement between the first and third positions. Prefer ably the third valve member is spring urged towards the third position.

Preferably the second valve member is disposed in a second transverse bore in the housing, parallel with the first bore.

A preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure I is a longitudinal section through part of a fluid-operated tool according to the invention; Figure 2 is an end view of the motor of the tool of Figure 1 showing the flow of fluid through the motor for reverse rotation; Figure 3 is a view similar to Figure 2 showing the flow for forward rotation; Figure 4 is a section along the line A-A of Figure 1 showing a reversing valve of the tool, (in a first mode of operation) positioned for reverse rotation; Figure 5 is a view similar to Figure 4 showing the valve positioned for forward rotation; Figure 6 to 8 are scrap sections along the lines B-B, C-C and D-D respectively of Figure 4; Figures 9 to 11 are scrap sections along the lines E-E, F-F and G-G respectively of Figure 5;; Figure 12 is a section along the line A-A of Figure 1 showing the reversing valve of the tool (in a second mode of operation) positioned for reverse rotation; Figure 13 is a view similar to Figure 12 showing the valve positioned for forward rotation; Figures 14 to 16 are scrap sections along the lines H-H, J-J and K-K respectively of Figure 12; and Figures 17 and 18 are scrap sections along the lines L-L and M-M respectively of Figure 13.

Referring first to Figures 1 to 3, a fluid operated tool, generally designated by 40, includes a housing 41 only one end portion of which is illustrated in Figure 1, and at the other end of which may be disposed suitable driving mechanism such as gears, clutches or the like of known type, for driving tool ends such as screwdriver blades, nut runners and the like. The driving mechanism and tool end of the tool 40 are of entirely conventional type and will not be described herein in any further detail.

The housing 41 defines a cylindrical bore 42 within which is disposed a fluid operated motor 43 for driving the tool which motor is shown schematically in Figure 1 and is depicted in Figures 2 and 3. The motor 43 is of the well known rotary vane type including a rotor member 12 having a plurality of radially movable vanes 44, the rotor being disposed in a cylinder 15 and having an axis of rotation parallel to but spaced from the axis of the cylinder. The motor 43 has an exhaust port 13 opening into passages 16 (Figures 4 and 5) in the housing 41 and inlet ports 11 and 19 (Figures 2 and 3) which are separately supplied with working fluid (usually air) under pressure to rotate the rotor 12 in opposite directions.As shown in Figure 2, for reverse (counter-clockwise) rotation, live air is supplied through port 11 and exhausts through port 13, scavenge air passing out through port 19 while, for forward (clockwise) rotation (Figure 3) live air is supplied to port 19 and exhausts through port 13, scavenge air passing out through port 11.

The housing 41 includes a handle portion generally designated by 46 which is generally hollow to permit the flow of air from an inlet nipple 47 to the motor 43. The inlet nipple is a stepped tubular member including a filter 48 for the inlet air. An annular exhaust chamber 17 surrounds the inlet nipple and exhaust air from the motor passes to atmosphere from chamber 17 via silencing material 18. The chamber 17 is connected to the passages 16 in the housing 41 and thence to the exhaust port 13 of the motor.

The handle portion 46 of the housing includes two parallel transverse bores 50, 51 which are interconnected by a passage 52 and are provided between the inlet nipple 47 and the holes 10 and 20. Bore 50 houses an on-off valve of the tool and bore 51 houses a reversing valve which will be described in more detail below.

The on-off valve comprises a generally cylindrical valve member 2 slidably located in a reduced diameter portion of the bore 50. The member 2 includes an annular groove 53 above an enlarged diameter flange 54 which retains an O-ring seal 55 in the groove 53. The O-ring seats on a shoulder 56 formed by a step in the bore 50 and is urged against the shoulder by a spring 57 retained in the bore 50 by a retaining screw 58. An end of the valve member 2 projects from the bore 50 to enable the valve member to be depressed to open the valve. As illustrated in Figure 1, a lever 3 is pivotally mounted on the handle portion 46 for depressing the valve member 2. The lever 3 may be replaced if desired by a button 60 and the upper end of valve 2 is internally screw threaded for receiving such a button. The tool may readily be changed from lever to button operation according to the preference of the user and the purpose for for which the tool is to be employed.

When the valve 2 is opened, inlet air to the tool 40 passes through nipple 47, filter 48 and port 1, flows around valve 2 and enters passage 52. Depending on whether forward or reverse rotation of the motor is desired, the live air must be diverted to either port 11 or port 19 of the motor and the reversing valve is provided for this purpose. The reversing valve comprises a generally cylindrical valve member 7 housed in a valve bush 5 located within bore 51. The bush 5 includes a port 4 aligned with passage 52 for the ingress of live air.

The valve member is movable within bush 5 between forward and reverse rotation positions and the valve member 7 includes porting and mounting cut-away portions which permit the movement from forward to reverse positions to be in either of two modes, rotary with respect to the axis of bore 51 or translational axially of bore 51.

The object of this arrangement is to provide a reversible tool which may, by a simple modification, have a "twist" reverse facility or a "push" reverse facility. This is desirable because for some users, the tool may predominantly be operating in one direction of rotation with only occasional necessity for a change and in this case the "twist" mode is preferred since it allows the tool to remain in either forward or reverse operation. In other applications it is necessary to provide an instant reverse facility and in these cases, the "push" mode of change is more conve nient. The reversing valve described pro vides facility for both these modes of change in one valve.

As stated above, the valve member 7 is a generally cylindrical member housed in bush 5. A spring 28 located between the upper end of member 7 and an end plate 62 urges the member 7 downwardly (as viewed in the drawings) and the member 7 is retained in the bush by a pin 27 (Figures 4, 5, 12 and 13) Reference will now be made particularly to Figures 4 to 11.

In the first "twist" mode of operation, the pin 27 engages in a groove 34 in the lower part of member 7, the groove 34 being circumferential and extending around approximately 1200 segment of the valve member 7. The pin is located in a hole 63 in bush 5 and retained in position by a clip 64.

Spring 28 loads the pin 27 against the upper edge of groove 34 and indents 35 (Figure 4) are provided at either end of groove 34 to "lock" the valve member 7 in these extreme positions while allowing the member 7 to be twisted from one position to the other by manual effort (see Figures 8 and 11 particularly).

The position for reverse rotation is illustrated in Figures 4 and 6 to 8. In this position live air entering the reversing valve through port 4 flows into a port 6 comprising a transverse cut-away segment of the member 7. "Transverse" will hereafter be used to describe ports of this type in member 7 while ports comprising channels extending longitudinally of the member 7 will be described as "longitudinal". From port 6, the live inlet air passes through an orifice 30 in bush 5, into a chamber 8 in the backhead of the motor housing 41, and thence via holes 10 into inlet port 11 of the motor to give reverse rotation of the rotor. Most of this air then passes out of port 13 into ports 16 and thence via exhaust chamber 17 to atmosphere.

The remainder of this air, the scavenge air, is then compressed by the rotating rotor 12 into port 19 of the motor and thence via holes 20 into a chamber 21 in the backhead.

The scavenge air in chamber 21 then enters a transverse port 22 in the reversing valve via an orifice 25 in the bush 5 and thence passes to a further transverse port 24 via a longitudinal connecting port 23. The transverse port 22 is diametrically opposite port 6 at the same level and is separated from port 6 at the same level and is separated from port 6 by a central core of the valve member 7. From port 24, the scavenge air passes through an orifice 29 and the valve bush 5 into one of the exhaust passages 16 and thence to atmosphere.

The position and air flow path for forward rotation in this first mode are illustrated in Figures 5 and 9 to 11. In this position, live air entering the reversing valve through port 4 enters port 6, passes via orifice 25 to chamber 21, and thence via holes 20 to inlet port 19 of the motor to cause forward rotation of the rotor. Again, most of this air is exhausted from the motor through port 13 to passages 16 and to atmosphere, but the scavenge air is compressed by the rotor into port 11. This scavenge air passes into chamber 8 through holes 10 and then via orifice 30 in the bush 5 into port 22 in the member 7. From port 22, the scavenge air passes down longitudinal connecting port 23 to transverse port 24.As can be seen in Figures 7 and 10 port 24 extends around approximately three quarters of the member 7 and is aligned with orifice 29 in the bush 5 in both the forward and reverse positions.

Thus, the scavenge air again passes through orifice 29 into exhaust passage 16 and thence to atmosphere.

Turning now to Figures 12 to 18, the second, "push" mode of operation of the reversing valve will be described. In this second mode, the retaining pin 27 engages in a longitudinal groove 31 in the valve member 7 to allow the member 7 to slide axially of the bush 5 against the action of spring 28. To effect the change from first to second mode, the clip 64 is removed and the pin 27 moved from hole 63 to a hole 66 in the bush 5 which is diametrically opposite hole 63. The clip is then replaced.

In this second mode, to position the valve member 7 for reverse rotation of the motor, the member 7 is pressed in manually against the action of spring 28 to the position shown in Figures 12 and 14 to 16. As can be seen from a comparison of Figures 12, 14 and 15 with Figures 4, 6 and 7, the air flow path to and from the motor for reverse rotation in the second mode is precisely the same as in the first mode and reference should be made to the pertinent description above. Figures 14 and 15 are included for ready comparison with Figures 17 and 18.

The position of valve member 7 and the air flow path for forward rotation in the second mode are illustrated in Figures 13, 17 and 18. Live air entering the valve member 7 via port 4 in bush 5 enters a transverse port 32, flows through orifice 25 in the valve bush 5 into chamber 21 and thence via holes 20 into inlet port 19 of the motor to cause forward rotation of the rotor 12. As can be seen in Figure 13, port 32 is the same shape as port 6 and is arranged above port 6 and rotated by approximately 1200 with respect thereto. Most of this air passes out of port 13 in cylinder 15 into exhaust passages 16 and thence to atmosphere via exhaust chamber 17 and silencing material 18.

The remaining, "scavenge" air is compressed by the rotor 12 into port 11 of the motor, and passes into chamber 8 via holes 10. This scavenge air then passes through orifice 30 into a transverse port 33 in the valve member 7. Port 33 is diametrically opposite port 32 and separated therefrom by the central core of the member 7. Port 33 is connected to ports 22 and 24 by the longitu dinal port 23 and so the scavenge air in port 33 flows via port 23 to port 24 and thence through orifice 29 into exhaust passage 16 and finally to atmosphere.

WHAT WE CLAIM IS: 1. A fluid operated tool of the kind described in which the reversing control means comprises a valve including a cylin drical valve member mounted in a housing of the tool in which said valve member is rotatably movable relative to the housing between a first position in which the tool fluid inlet is connected to a first of the motor inlets and a second position in which the tool fluid inlet is connected to the second motor inlet and said valve member is alter natively slidably movable relative to said housing between said first position and a third position in which the tool fluid inlet is connected to the second motor inlet.

2. A tool as claimed in claim 1 in which the fluid operated motor is of the rotary vane type.

3. A tool as claimed in claim 1 or claim 2 further comprising a second valve upstream of the first valve, said second valve being operable to connect and disconnect the tool fluid inlet from the first valve.

4. A tool as claimed in claim 3 in which the second valve includes a slide valve member which is mounted in the housing of the tool.

5. A tool as claimed in claim 4 in which an extension of the slide valve member protrudes from the housing and a lever is provided pivoted on the housing, for moving said slide valve member between open and closed positions, against the action of a Spnng.

6. A tool as claimed in claim 4 or claim 5 in which the valve member is adapted to have a button connected thereto for operating the valve instead of the lever.

7. A tool as claimed in claim 6 when dependent on claim 5 in which the extension of the valve member is screw-threaded for receiving a button.

8. A tool as claimed in any one of the preceding claims in which the housing of the tool includes an elongate cylindrical chamber in which the motor is arranged with its axis of rotation parallel to the axis of the chamber, and the first valve member is located in a transverse cylindrical bore formed in the housing, said bore including an inlet orifice in communication with the tool fluid inlet and two outlet orifices in communication with the two motor fluid inlets.

9. A tool as claimed in claim 8 in which the valve member of the first valve includes a first port for connecting the inlet orifice to a first outlet orifice in the first position and to the second outlet orifice in the second position and a second port for connecting the inlet orifice to the second outlet orifice in the third position.

10. A tool as claimed in claim 8 or claim 9 in which the first valve bore includes a third outlet orifice in communication with an exhaust outlet of the tool and the first valve member includes a third port in communication with said third outlet orifice and connected by a fourth port to a fifth port which is in communication with the second outlet orifice in the first position and with the first outlet orifice in the second position and further connected to a sixth port which is in communication with the first outlet orifice in the third position.

11. A tool as claimed in any one of the preceding claims in which the first valve member includes a circumferential groove which is engaged by a pin to limit movement between the first and second positions and a longitudinal groove which is alternatively engaged by a pin to limit movement between the first and third positions.

12. A tool as claimed in any one of the preceding claims in which the first valve member is spring urged towards the third position.

13. A tool as claimed in any one of claims 8 to 10 when dependent on any one of claims 4 to 7 in which the second valve

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Claims

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the action of spring 28 to the position shown in Figures 12 and 14 to 16. As can be seen from a comparison of Figures 12, 14 and 15 with Figures 4, 6 and 7, the air flow path to and from the motor for reverse rotation in the second mode is precisely the same as in the first mode and reference should be made to the pertinent description above. Figures 14 and 15 are included for ready comparison with Figures 17 and 18.

The position of valve member 7 and the air flow path for forward rotation in the second mode are illustrated in Figures 13, 17 and 18. Live air entering the valve member 7 via port 4 in bush 5 enters a transverse port 32, flows through orifice 25 in the valve bush 5 into chamber 21 and thence via holes 20 into inlet port 19 of the motor to cause forward rotation of the rotor 12. As can be seen in Figure 13, port 32 is the same shape as port 6 and is arranged above port 6 and rotated by approximately 1200 with respect thereto. Most of this air passes out of port

13 in cylinder 15 into exhaust passages 16 and thence to atmosphere via exhaust chamber 17 and silencing material 18.

The remaining, "scavenge" air is compressed by the rotor 12 into port 11 of the motor, and passes into chamber 8 via holes 10. This scavenge air then passes through orifice 30 into a transverse port 33 in the valve member 7. Port 33 is diametrically opposite port 32 and separated therefrom by the central core of the member 7. Port 33 is connected to ports 22 and 24 by the longitu dinal port 23 and so the scavenge air in port

33 flows via port 23 to port 24 and thence through orifice 29 into exhaust passage 16 and finally to atmosphere.

WHAT WE CLAIM IS: 1. A fluid operated tool of the kind described in which the reversing control means comprises a valve including a cylin drical valve member mounted in a housing of the tool in which said valve member is rotatably movable relative to the housing between a first position in which the tool fluid inlet is connected to a first of the motor inlets and a second position in which the tool fluid inlet is connected to the second motor inlet and said valve member is alter natively slidably movable relative to said housing between said first position and a third position in which the tool fluid inlet is connected to the second motor inlet.
2. A tool as claimed in claim 1 in which the fluid operated motor is of the rotary vane type.
3. A tool as claimed in claim 1 or claim 2 further comprising a second valve upstream of the first valve, said second valve being operable to connect and disconnect the tool fluid inlet from the first valve.
4. A tool as claimed in claim 3 in which the second valve includes a slide valve member which is mounted in the housing of the tool.
5. A tool as claimed in claim 4 in which an extension of the slide valve member protrudes from the housing and a lever is provided pivoted on the housing, for moving said slide valve member between open and closed positions, against the action of a Spnng.
6. A tool as claimed in claim 4 or claim 5 in which the valve member is adapted to have a button connected thereto for operating the valve instead of the lever.
7. A tool as claimed in claim 6 when dependent on claim 5 in which the extension of the valve member is screw-threaded for receiving a button.
8. A tool as claimed in any one of the preceding claims in which the housing of the tool includes an elongate cylindrical chamber in which the motor is arranged with its axis of rotation parallel to the axis of the chamber, and the first valve member is located in a transverse cylindrical bore formed in the housing, said bore including an inlet orifice in communication with the tool fluid inlet and two outlet orifices in communication with the two motor fluid inlets.
9. A tool as claimed in claim 8 in which the valve member of the first valve includes a first port for connecting the inlet orifice to a first outlet orifice in the first position and to the second outlet orifice in the second position and a second port for connecting the inlet orifice to the second outlet orifice in the third position.
10. A tool as claimed in claim 8 or claim 9 in which the first valve bore includes a third outlet orifice in communication with an exhaust outlet of the tool and the first valve member includes a third port in communication with said third outlet orifice and connected by a fourth port to a fifth port which is in communication with the second outlet orifice in the first position and with the first outlet orifice in the second position and further connected to a sixth port which is in communication with the first outlet orifice in the third position.
11. A tool as claimed in any one of the preceding claims in which the first valve member includes a circumferential groove which is engaged by a pin to limit movement between the first and second positions and a longitudinal groove which is alternatively engaged by a pin to limit movement between the first and third positions.
12. A tool as claimed in any one of the preceding claims in which the first valve member is spring urged towards the third position.
13. A tool as claimed in any one of claims 8 to 10 when dependent on any one of claims 4 to 7 in which the second valve

member is disposed in a second transverse bore in the housing, parallel with the first bore.
14. A fluid operated tool substantially as hereinbefore described with reference to and as shown in the accompanying draw ings.