GB2037376A - Remote Control System - Google Patents

Abstract

A remote control system for controlling the movement of a member (2) comprises a first piston and cylinder means (3, 4) connected to the member, a fluid path (7) extending from the first piston and cylinder means to a control station remote from the member, means (5, 6) for driving fluid down the fluid path into the first piston and cylinder means, a flexible tension bearing mechanical coupling (9), and means (17) for applying tension to the member, the tension applying means being located at the control station and being connected to the member via the mechanical coupling, the arrangement being such that driving fluid down the fluid path into the first piston and cylinder means moves the member in one direction and applying tension to the mechanical coupling moves the member in the opposite direction. <IMAGE>

Description

SPECIFICATION Remote Control System This invention relates to remote control systems.

According to the invention a remote control system for controlling the movement of a member comprises a first piston and cylinder means connected to the member, a fluid path extending from the first piston and cylinder means to a control station remote from the member, means for driving fluid down the fluid path into the first piston and cylinder means, a flexible tension bearing mechanical coupling, and means for applying tension to the member, the tension applying means being located at the control station and being connected to the member via the mechanical coupling, the arrangement being such that driving fluid down the fluid path into the first piston and cylinder means moves the member in one direction and applying tension to the mechanical coupling moves the member in the opposite direction.

The flexible tension bearing mechanical coupling may be a Bowden cable. One particular form of Bowden cable which may be used is one having a movable inner member supported on ball bearings. Such cables are known per se.

One end of the mechanical coupling may be connected to the first piston and cylinder means, the other end of the coupling being connected to the tension applying means. Instead of connecting the coupling to the first piston and cylinder means the coupling may be connected directly to the member whose movement is to be controlled.

The member whose movement is to be controlled may be connected to a piston of the first piston and cylinder means, the cylinder in which said piston is mounted being fixed.

The fluid path and the first piston and cylinder means may form part of hydraulic system.

The mechanical coupling may be disposed in the fluid path.

The means for driving fluid down the fluid path into the first piston and cylinder means may comprise another piston and cylinder means at the control station and in communication with the fluid path and means for operating said another piston and cylinder means. The means for operating said another piston and cylinder means may be a motor; alternatively said another piston and cylinder means may be operated manually, for example through a lever or screw system. The motor may be an electric stepping motor or a D.C.

motor whose output shaft is positionally controlled electronically. The motor may also be used to apply tension to the mechanical coupling.

The mechanical coupling may be connected to the second piston and cylinder means.

The means for applying tension to the member may comprise a piston and cylinder means and means for applying fluid pressure to this piston and cylinder means. The movement of the tension applying piston and cylinder means corresponds to the movement of the first piston and cylinder means and may be used to provide a feedback signal of the position of the first piston and cylinder means.

The means for applying fluid pressure to the first and tension applying piston and cylinder means may comprise a source of high pressure fluid and valve means interposed between the high pressure source and the first and tension applying piston and cylinder means. The valve means may have a neutral state in which the high pressure source is disconnected from both the first and tension applying piston and cylinder means, a first state in which the high pressure source is connected to the first piston and cylinder means and a second state in which the high pressure source is connected to the tension applying piston and cylinder means. The state of the valve means may be controlled according to the combination of the position of an output shaft of a motor and a feedback signal of the position of the memory whose movement is to be controlled.

The motor may be an electric stepping motor or a D.C. motor whose output shaft is positionally controlled electronically.

According to another aspect of the invention a brush making machine includes a holder for a brush stock and at least one operating head for inserting and securing bristle tufts in the brush stock, the holder for the brush stock being movably mounted on a first frame, the first frame being movably mounted on a second frame, and the second frame being movably mounted on a third frame, wherein the movement of the holder relative to the first frame or of one frame relative to another frame is controlled by a remote control system as defined above.

The movement of the holder relative to the first frame, the movement of the first frame relative to the second frame and the movement of the second frame relative to the third frame may each be controlled by a respective remote control system as defined above.

The third frame may be movably mounted on the base of the machine. The movement of the third frame relative to the base may be controlled by another remote control system as defined above.

The relative movements may be sliding movements and/or pivotal movements. In one embodiment of the invention the brush stock holders are mounted on the first frame for horizontal sliding movement relative thereto, the first frame is mounted on the second frame for pivoting movement relative thereto about a horizontal axis parallei to the movement of the holder relative to the first frame, the second frame is mounted on the third frame for horizontal sliding movement relative thereto transverse to the movement of the holder relative to the first frame, and the third frame is mounted on the base for vertical sliding movement relative thereto.

The control station for each of the remote control systems may be located on the base of the machine.

By way of example, certain illustrative embodiments of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a schematic view of a first remote control system; Figure 2 is a schematic view of a second remote control system; Figure 3 is a schematic view of a third remote control system; Figures 4A and 4B are schematic side elevation views of a brush-making machine; Figures 5A and 5B are schematic end elevation views of the brush-making machine shown in Figures 4A and 4B; and Figure 6 is a schematic view of a fourth remote control system.

Referring first to Figure 1, a remote control system 1 for controlling the movement of a member 2 comprises a first piston and cylinder means consisting of a piston 3 attached to the member 2 and a cylinder 4, and a second piston and cylinder means which is the same size as the first and consists of a piston 5 and a cylinder 6. A flexible hydraulic hose 7 provides a fluid path between the cylinders 4 and 6 and an accumulator 8 maintains the pressure in the hydraulic system.

A flexible Bowden cable 9, having a moving inner member 10 and which in this particular example is a ball bearing cable, connects the piston 3 to the piston 5 and glands 11 seal the points of entry of the member 1 0 into the cylinders 4 and 6.

The piston 5 is connected to a tube 1 2 which is mounted for sliding movement along the axis of the cylinder 6 but prevented from rotation by a cross member 1 3 slidably mounted by slide bars 14. The tube 12 carries a nut 1 5 which is fixed to the tube 12 and which is engaged by a lead screw 1 6 driven through a toothed belt drive by a stepping motor 17.

In operation of the remote control system the piston 5 is moved relative to the cylinder 6 by the stepping motor 1 7 operating through the lead screw 1 6 and nut 1 5. Movement of the piston 5 to the right (as seen in Figure 1) forces hydraulic fluid out of the cylinder 6 and into the cylinder 4 thereby moving the piston 3 and member 2 to the right (as seen in Figure 1). The movement of the piston 3 to the right is also encouraged by a compressive force developed in the inner member 10 of the Bowden cable but since the hydrautic coupling acts as a much more rigid link than the mechanical coupling. When the couplings are in compression by far the greater proportion of the force transmitted to the piston 3 is derived from the hydraulic coupling.

Movement of the piston 5 to the left (as seen in Figure 1) creates a tension force in the inner member 10 of the Bowden cable and this pulls the piston 3 and member 2 to the left (as seen in Figure 1). Since the Bowden cable is strong and rigid in tension whereas the hydraulic coupling is comparatively weak by far the greater proportion of the force transmitted to the piston 3 is in this case derived from the mechanical coupling.

Thus it will be seen that the movement of the piston 3 and member 2 copies the movement of the piston 5 which is controlled by the stepping motor 1 7. The stepping motor 17, the piston and cylinder 5, 6 and the accumulator 8 are all located at a control station while the piston and cylinder 3, 4 and the member 2 are at a remote location. The only connections to the remote location are therefore a flexible Bowden cable and one hydraulic hose. These members can be several metres long if desired without affecting the performance of the system and their flexibility enables them to be used in confined spaces and led along tortuous paths.

Although in Figure 1 the accumulator 8 is shown connected in the path of the hydraulic hose 7, it may alternatively be connected by a separate hydraulic hose to the cylinder 6. In this case the hydraulic hose 7 may be provided around the Bowden cable 9 enclosing the cable. This arrangement eliminates the need for the glands 11 and means that there is only a single connection between the first and second piston and cylinder means.

Referring now to Figure 2 a remote control system 21 for controlling the movement of a member 22 comprises a first piston and cylinder means consisting of a piston 23 attached to the member 22 and a cylinder 24, and a second piston and cylinder means consisting of a piston 25 and a cylinder 26. A flexible hydraulic hose 27 provides a fluid path between the cylinder 24 and a first port of a valve 28.

A flexible Bowden cable 29 having a moving inner member 30 connects the piston 23 to the piston 25 and glands 31 seal the points of entry of the member 30 into the cylinders 24 and 26.

A hydraulic hose 32 connects the cylinder 26 to a second port of the valve 28 which is also connected to the supply and return lines 37 of a hydraulic system.

A rod 33 is connected at one end to the piston 25 and together with the piston 25 is slidably mounted in the cylinder 26. The other end of the rod 33 is connected to a rack 34 which engages a pinion 35 carried on a shaft extending out of the valve 28. Another shaft extending out of the valve 28 is connected to a stepping motor 36 which drives the valve.

The valve 28 has three states. In the first state which is a neutral state the first and second ports of the valve 28 are closed and the pistons 23 and 25 are held in a fixed position. If the stepping motor 36 is now actuated in one direction the ports of the valve are opened, the hydraulic hose 27 is connected to the supply line of the hydraulic system and the hydraulic hose 32 is connected to the return line. This forces hydraulic fluid into the cylinder 24 thereby moving the piston 23 and the member 22 to the right (as seen in Figure 2).

Movement of the piston 23 to the right causes, through the tension in the inner member 30 of the Bowden cable, the piston 25 to move to the right thereby expelling hydraulic fluid from the cylinder 26 along the return line of the hydraulic system.

Movement of the piston 25 to the right moves the rack 34 to the right thereby rotating the pinion 35. Rotatidn of the pinion 35 in this direction tends to return the valve 28 to its neutral state; the amount of rotation of the pinion 35 that is required to return the valve 28 to its neutral state is directly proportional to the amount of rotation of the stepping motor 36 in actuating the valve.

For example if the stepping motor 36 rotates once in moving the valve out of the neutral state, the pinion 35 will have to rotate K times (where K is a constant) to return the valve 28 to its neutral position and if the stepping motor 36 rotates twice in moving the valve out of the neutral state, the pinion 35 will have to rotate 2K times to return the valve to its neutral state.

If the stepping motor 36 is actuated in the opposite direction to that just described, the ports of the valve are again opened but in this case the hydraulic hose 32 is connected to the supply line of the hydraulic system and the hydraulic hose 27 is connected to the return line. This forces hydraulic fluid into the cylinder 26 thereby moving the piston 25 to the left (as seen in Figure 2). Movement of the piston 25 to the left applies tension to the inner member 30 of the Bowden cable and pulls the piston 23 and member 22 to the left thereby expelling hydraulic fluid from the cylinder 24 along the return line of the hydraulic system.

The movement of the piston 25 to the left moves the rack 34 to the left thereby rotating the pinion 35 in the opposite sense to that described above. Rotation of the pinion 35 in this direction tends to return the valve 28 to its neutral state.

Thus, for example, if the stepping motor 36 rotates twice in said opposite direction, the pinion 35 will have to rotate 2K times to return the valve 28 to its neutral state.

From the description above, it will be seen that in the arrangement shown in Figure 2, the position of the member 22 is controlled by the stepping motor 36 as in Figure 1, but the power for moving the member 22 is derived from the hydraulic system 37 and not from the motor 36, and a feedback system consisting of the rack 34 and pinion 35 are therefore required to provide a feedback signal of the position of the member 22.

Figure 3 shows a remote control system 41 for controlling the movement of a member 42. The system comprises a first piston and cylinder means consisting of a piston 43 attached to the member 42 and a cylinder 44, and a second piston and cylinder means consisting of a piston 45 and a cylinder 46. A flexible hydraulic hose 47 provides a fluid path between the cylinder 44 and a first port of a valve 48.

A flexible Bowden cable 49 having a moving inner member 50 connects the piston 43 to the piston 45 and glands 51 seal the points of entry of the member 50 into the cylinder 44 and 46.

A hydraulic hose 52 connects the cylinder 46 to a second port of the valve 48 which is also connected to the supply and return iines 59 of a hydraulic system.

A rod 53 is connected at one end to the piston 45 and together with the piston 45 is slidably mounted in the cylinder 46. The other end of the rod 53 carries a cam 54 with an inclined camming surface 55 which is engaged by a cam follower extending out of the valve 48. The valve 48 carries a nut (not shown) which engages a lead screw 57 which is connected to a stepping motor 56 so that rotation of the lead screw 57 by the stepping motor 56 moves the valve 48 along the lead screw.

The valve 48 has three states. In the first state, which is a neutral state, the cam follower is approximately halfway up the camming surface 55 and the first and second ports of the valve 48 are closed and the pistons 43 and 45 are held in a fixed position. In the second state, the cam follower is higher up the camming surface 55, the hydraulic hose 47 is connected to the supply line of the hydraulic system and the hydraulic hose 52 is connected to the return line. In the third state, the cam follower is lower down the camming surface 55, the hydraulic hose 52 is connected to the supply line of the hydraulic system and the hydraulic hose 47 is connected to the return line.

If the stepping motor 56 is actuated so as to move the valve 48 to the right (as seen in Figure 3) this switches the valve 48 to its second state so that, as described with reference to Figure 2, the member 42 and pistons 43 and 45 move to the right, and once the pistons 43 and 45 have moved the same distance as the valve 48, the valve returns to its neutral state. If the stepping motor 56 is actuated in the opposite direction so as to move the valve 48 to the left (as seen in Figure 3) this switches the valve 48 to its third state so that, as described with reference to Figure 2, the member 42 and pistons 45 move to the left, and once the pistons 43 and 45 have moved the same distance as the valve 48, the valve returns to its neutral state.

Thus it will be seen that the system 41 shown in Figure 3 is quite similar two the system 21 shown in Figure 2 but differs in the arrangement for providing a feedback signal of the position of the pistons in their cylinders. In the remote control systems 21 and 41 the piston and cylinder arrangements 23, 24 and 43, 44 are situated at a remote location but the other piston and cylinder arrangements 25, 26 and 45, 46, the valves 28 and 48, and the stepping motors 36 and 56 are located at a control station. Also, as in the control system 1 shown in Figure 1 the only connections to the remote location are a flexible Bowden cable and a hydraulic hose.

The remote control systems described above may be used in a great many applications. One application for which they are particularly suitable is controlling the movement of brush stock holders in a brush making machine. This application of the systems shown in Figures 1 to 3 will now be explained with reference to Figures 4A, 4B. 5A and 5B which illustrate a typical supporting arrangement for a set of brush stock holders (other parts of the brush making machine not being shown).

Referring first to Figures 4A and 4B the brush making machine shown in the drawings has a plurality of,operating heads 61 for drilling holes in brush stocks (not shown) mounted on respective brush stock holders 62, and for inserting and securing bristle tufts into the holes drilled in the brush stocks. Various arrangements of operating heads 61 may be used according to the particular design of machine but these are well known to those skilled in the art and will not be described further. The brush stock holders 62 and operating heads 61 are not shown in Figures 5A and 5B.

The brush stock holders 62 are mounted on uprights (not shown) which are slidably mounted on a first frame 63. The holders 62 may be fixed to the uprights or they may be pivotally connected to the uprights. The holders 62 are moved relative to the frame 63 by a rod 64 whose movement is controlled by a remote control system of any of the forms shown in Figures 1 to 3; the remote piston and cylinder means of the system is mounted on the frame 63 and is designated by the reference numeral 65 in Figures 4A and 4B.

The movement of the holders 62 may be either of two modes: in a first mode illustrated in Figure 4A the brush stock holders 62 are fixed to their uprights and slide horizontally relative to the first frame 63; in a second mode illustrated in Figure 48 the brush stock holders 62 are pivotally mounted on their uprights and the uprights are prevented from sliding horizontally relative to the first frame 63 so that movement of the rod 64 pivots the brush stock holders 62.

Referring now to Figures 4A, 4B, 5A and 5B the first frame 63 is pivotally mounted by plates 66 on a second frame 71. The axis of pivoting 67 of the plates 66 is a horizontal axis parallel to the direction of sliding movement of the brush stock holders 62 relative to the first frame 63. The pivotal movement of the first frame 63 is controlled by another remote control system of any of the forms shown in Figures 1 to 3; the remote piston and cylinder means of the system is mounted between a pivot 68 on the first frame 63 and a pivot 69 on the second frame 71 and is designated by the reference numeral 70.

The second frame 71 is slidably mounted on slide bars 72 of a third frame 73 for sliding movement in a horizontal direction perpendicular to the direction of sliding movement of the brush stock holders 62. The sliding movement of the second frame 71 is controlled by another remote control system of any of the forms shown in Figures 1 to 3; the remote piston and cylinder means of the system is designated by the reference numeral 75, is mounted on the slide bars 72 and is connected to a lug 74 fixed to the second frame 71.

The third frame 73 is slidably mounted on slide bars 76 attached to a base 77 of the machine for sliding vertical movement. The sliding vertical movement of the third frame 73 is controlled by another remote control system of any of the forms shown in Figures 1 to 3; the remote piston and cylinder means of the system is designated by the reference numeral 78 and is connected between the base 77 and the third frame 73 of the machine.

In operation of the machine the brush stock holders are moved in the required directions by the combination of the movements described above controlled by the four remote control systems. The control stations of the remote control systems are located on the base of the machine and a respective hydraulic hose and a respective Bowden cable lead from the base of the machine to each of the piston and cylinder means 65, 70, 75 and 78.

This arrangement for moving the brush stock holders in a brush making machine has various advantages over methods which have been used in the past. In one prior arrangement each of the drives for the movements of the brush holders has been mounted on a stationary part of the machine. This makes connection of some of the drives difficult; for example, the drive for sliding the brush stock holders 62 relative to the first frame 63 must be able to accommodate the movement of the holders due to pivoting of the first frame 63, sliding of the second frame 71, and sliding of the third frame 73. Thus it is preferable to mount the various drives directly on the various moving parts of the machine.However with prior drive arrangements, this involves mounting bulky and heavy units on the moving parts of the machine so that the power consumption of the machine is considerably increased and so is its size. In contrast, in the machine shown in Figure 4 a single acting piston and cylinder is the only component mounted on any moving part of the machine; furthermore the only connections which have to be made to each piston and cylinder are one hydraulic hose and one Bowden cable and both of these connections may follow the most convenient path which provides least obstruction to the other working parts of the machine.The use of a mechanical coupling (the Bowden cable) to move the piston in one direction is particularly advantageous since it enables the piston and cylinder arrangements to be a single acting piston and cylinder rather than a double acting piston and cylinder which wouid be larger and heavier.

Different brush machines will have a different number of movements and the nature of these movements will also differ according to the design of the machine. Thus it may be that only one control system will be required to control the machine movements of a brush machine embodying this invention.

While various particular embodiments of the invention have been described many modifications may be made. For example, the remote control system of Figure 1 may be modified in the manner shown in Figure 6 in which parts which are also shown in Figure 1 are referenced by the same reference numerals as in Figure 1. In this modification the stepping motor 17, screw 16 and nut 15 are replaced by a unit 90 consisting of a stepping motor 136, a valve 128 and a double acting piston and cylinder 126.

The unit 90 is equivalent to the combination of elements shown in the left hand side of Figure 2, namely the motor 36, valve 28, rack 34, pinion 35, rod 33, piston 25 and cylinder 31, but with the hydraulic line 27 connected to the right hand end of the cylinder 26 (instead of the cylinder 24) and the piston 25 connected to the piston 5 (instead of directly to the inner member 30 of the Bowden cable 29) and equivalent parts are referenced by the same reference numerals as are used in Figure 2 preceded by the numeral 1. Since the valve 128 is built in a single unit with the cylinder 126 the feedback system from the piston 125 in the cylinder 126 to the valve 128 can be simplified, the rack 34 and pinion 35 being omitted.

The remote control system shown in Figure 6 may be used in the brush making machine shown in Figures 4A, 4B, 5A and 5B as any of the remote control systems described in a similar manner to the remote control system shown in Figure 1.

The Bowden cable shown in Figures 1 to 3 and 6 may be replaced by any other flexible mechanical coupling which is able to transmit tensile forces. For example, a cable made of flexible steel, terylene or a similar material could be used without any outer covering, the cable being guided over pulleys or low friction static surfaces. The stepping motors may be replaced by another form of motor, for example a D.C. motor whose output shaft is positionally controlled electronically.

Claims (12)

Claims

1. A remote control system for controlling the movement of a member comprising a first piston and cylinder means connected to the member, a fluid path extending from the first piston and cylinder means to a control station remote from the member, means for driving fluid down the fluid path into the first piston and cylinder means, a flexible tension bearing mechanical coupling, and means for applying tension to the member, the tension applying means being located at the control station and being connected to the member via the mechanical coupling, the arrangement being such that driving fluid down the fluid path into the first piston and cylinder means moves the member in one direction and applying tension to the mechanical coupling moves the member in the opposite direction.

2. A system as claimed in claim 1 in which the flexible tension bearing mechanical coupling is a Bowden cable.

3. A system as claimed in claim 1 or 2 in which one end of the mechanical coupling is connected to the first piston and cylinder means, the other end of the coupling being connected to the tension applying means.

4. A system as claimed in any preceding claim in which the member whose movement is to be controlled is connected to a piston of the first piston and cylinder means, the cylinder in which said piston is mounted being fixed.

5. A system as claimed in any preceding claim in which the fluid path and the first piston and cylinder means form part of hydraulic system.

6. A system as claimed in any preceding claim in which the mechanical coupling is disposed in the fluid path.

7. A system as claimed in any preceding claim in which the means for driving fluid down the fluid path into the first piston and cylinder means comprises another piston and cylinder means at the control station and in communication with the fluid path and means for operating said another piston and cylinder means.

8. A system as claimed in any preceding claim in which the means for applying tension to the member comprises a piston and cylinder means and means for applying fluid pressure to this piston and cylinder means.

9. A system as claimed in any preceding claim in which the means for applying fluid pressure to the first and tension applying piston and cylinder means may comprise a source of high pressure fluid and valve means interposed between the high pressure source and the first and tension applying piston and cylinder means. The valve means may have a neutral state in which the high pressure source is disconnected from both the first and tension applying piston and cylinder means, a first state in which the high pressure source is connected to the first piston and cylinder means and a second state in which the high pressure source is connected to the tension applying piston and cylinder means.The state of the valve means may be controlled according to the combination of the position of an output shaft of a motor and a feedback signal of the position of the member whose movement is to be controlled.

The motor may be an electric stepping motor or a D.C. motor whose output shaft is positionally controlled electronically.

10. A brush making machine including a holder for a brush stock and at least one operating head for inserting and securing bristle tufts in the brush stock, the holder for the brush stock being movably mounted on a first frame, the first frame being movably mounted on a second frame, and the second frame being movably mounted on a third frame, wherein the movement of the holder relative to the first frame or of one frame relative to another frame is controlled by a remote control system as defined above.

11. A machine as claimed in claim 10 in which the movement of the holder relative to the first frame, the movement of the first frame relative to the second frame and the movement of the second frame relative to the third frame are each be controlled by a respective remote control system as defined above.

12. A machine as claimed in claim 10 or 11 in which the third frame is movably mounted on the base of the machine.