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(11) | EP 0 039 550 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A control arrangement for producing motion |
| (57) Hydraulic control arrangements for operation from the bridge of a ship are disclosed.
In each example, a cam (19) can be displaced linearly by a cable (20) from the bridge
to control a valve (9) via a lever (21) having a cam-following roller (22) which co-operates
with the camming surface (23) of the cam (19). In response to displacement of the
cam (19), the valve (9) causes oil to be fed to a cylinder (6) so that the latter
is displaced, thereby displacing a carriage (2) until the lever (21) adopts a position
with its roller (22) approximately mid-way along the camming surface (23), whereupon
the valve (9) stops the flow of oil and the carriage (2) stops. In one example, a
cam (34) is carried by the carriage (2) for displacing a lever (35) as a result of
movement of the carriage (2), the lever (35) being connected to control the speed
of an engine of the ship via a cable (38); and another lever (25) carried by the carriage
(2) is connected to the pitch setting mechanism of a controllable pitch propeller
via a cable (30) for altering the pitch of a controllable pitch propeller of the ship
as a result of displacement of the carriage (2). In another example, instead of the
other lever (25) for controlling the setting of a controllable pitch propeller, there
is another lever (41) pivotally mounted and displaced as a result of movement of the
carriage (2) by cams (39 and 40) carried by the carriage (2), the other lever (41)
being connected to control a reversible gearbox for the engine via a cable (49). In
each example, the carriage moves at a given speed lower than that of displacement
of the cam (19) irrespective of the speed of the displacement of the cam if the latter
is greater than the given speed. |
[0001] This invention relates to a control arrangement for producing motion, for example a control arrangement which can be operated from the bridge of a vessel for controlling the speed of an engine and the pitch of a controllable pitch propeller or the speed of an engine and a reversing gearbox.
[0002] According to this invention, there is provided a control arrangement for producing motion comprising:
first means, which can be displaced to any one of a plurality of positions at any one of a plurality of speeds;
a fluid-operated cylinder and piston;
second means, arranged to be responsive to the position of the first means and to be actuated in response to displacenent of the first means from a first to a secrnd position, in use of the arrangement, to triger relative displacement between the cylinder and the piston at a substantially constant speed less than that of displacement of the first means if the speed of displacement of the first means is grater than a given speed, until the second means responds to the second position of the first means; and
third neans, displaced as a result of relative a/splacement between the cylinder and piston.
[0004] The said first means could comprise a cam, for example a cam arranged for linear displacement.
[0005] The said second means could comprise follower means for co-operating with the first means and a valve controlled by the follower means for controlling the supply of f lutq to the said cylinder. In this case, the said valve could be provided with means for adjusting the rate of flow of fluid, for adjusting the speed of relative displacement between the cylinder and distance.
[0006] The said third means could comprise an actuating member. For example, the actuating member could be an actuating lever in which case it could be provided with an associated cam which co-operates with it. In this case, the said third means could further comprise a carriage which is displaced relative to a frame as a result of relative displacement between the cylinder and piston, the said actuating lever being pivotally mounted on either the frame or the carriage and the associated cam being mounted on the other of the frame and the carriage. The third means could further comprise a further actuating member, carried by the carriage. For example, the further actuating member could comprise a further actuating lever, in which case there could be fourth means, for normally preventing pivoting of the further actuating lever during displacement of the carriage. The arrangement could be such that the first actuating lever is suitable for controlling the speed of a vessel's engine and the further actuating lever is suitable for controlling the pitch of a controllable pitch propeller. In this case, there could be pushing means for pivoting back the further actuating lever in response to engine overload. Moreover, such fourth means could be arranged for accommodating excessive force applied by the further actuating lever.
[0007] Instead of such a further actuating lever carried by the carriage, the said third means could further comprise a further actuating lever provided with an associated cam which co-operates with it, the further lever being pivotally mounted on either the carriage or the frame and the associated cam being mounted on the other of the carriage and the frame. In this case, the arrangement could be such that the first actuating lever is suitable for controlling the speed of a vessel's engine and the further actuating lever is suitable for controlling a reversible gearbox for such an engine.
[0008] This invention will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 is a schematic view of a first example of an arrangement according to this invention;
Figure 2 shows items omitted from Figure 1, the arrangement being suitable for use in controlling, from a ship's bridge, the speed of a diesel engine of the ship and the pitch of a controllable pitch propeller of the ship;
Figure 3 shows items which can be used in the arrangement instead of some of those of Figure 1, whereby the arrangement is suitable for use in controlling, from a ship's bridge, the speed of a diesel engine of the ship and a reversible gearbox for the engine;
Figure 4 is a perspective view of part of a practical form of either of the exanples; and
Figure 5 is a longitudinal section through part of an alternative to Figure 2, Figure 6 being a view in the direction A-A in Figure 5.
[0009] Referring first to Figure 1, a frame 1 provides an enclosure for a carriage 2 which can slide in a linear manner along shafts 3 and 4 fixed to the frame, the carriage 2 being provided with bearings 5. Fixed on the carriage 2 is an hydraulic cylinder 6 whose piston rod 7 is fixed to the frame 1. Oil can be admitted to one side or the other of the piston 8 of the cylinder 6 for causing displacement of the cylinder 6 and thereby the carriage 2 via an hydraulic valve 9. Oil can be pumped through the valve 9, when the latter is actuated, by means of a pump 10 from an oil reservoir 11, the valve being provided with an adjustable restrictor 12, the setting of which restrictor determines the speed of displacement of oil and thereby the speed of displacement of the carriage 2. The hydraulic lines 13 and 14 from ports of the valve 9 to respective sides of the piston 8 are rigid lines on the carriage 2; and the hydraulic line 15 from the restrictor 12 (the return line to the reservoir 11) and the hydraulic line 16 to the pump are flexible lines.
[0010] Slidable in a linear manner along rods 17 and 18 fixed to the frame 1 is a cam 19, this being displaceable by means of a.cable 20 connected in use of the . arrangement to a lever on the bridge of a ship. Pivotally mounted on the carriage 2 for actuating the valve 9 is a lever 21 which carries a cam-following roller 22. The roller 22 is normally approximately mid-way along thecamming surface 23 of the cam 19. Also, the lever 21 carries an adjustable valve port setting screw 24.
[0011] Pivotally attached to the carriage 2 is a further lever 25. The lever 25 is normally held in the upright position shown,and pivoting movement resisted,by means of a shaft 26 extending into a cylinder 27 which is pivotally attached to the carriage 2. A spring 28 is held between two flanges 29 on the shaft 26 to normally resist pivoting of the lever 25.. The lever 25 is connected to a cable 30 which, in use of the arrangement,is connected to a controllable pitch propeller setting mechanism.
[0012] Also mounted on the frame 1 is a pair of hydraulic cylinders 31 and, in use of the arrangement, if engine overload is detected, oil is admitted via hydraulic lines 32 to cause inward displacement of the piston rods 33.
[0013] Referring now to Figure 2, also fixed to the carriage 2 on the top thereof and mid-way along, is a cam 34. A bell crank lever 35 is pivotally fixed to the frame 1 via a cylindrical portion 36 and the lever 35 has.a cam-following roller 37 which co-operates with the cam 34. One end of a cable 38 is pivotally connected to the lever 35 andin use of the arrangement/its other end is connected to the speed control of the ship's engine, for example to a governor. The details of Figure 2 are not included in Figure 1 for the sake of clarity.
[0014] Operation of the arrangement according to Figures 1 and 2 is as follows. Displacement of the lever on the bridge causes linear displacement of the cable 20 and thereby a corresponding linear displacement of the cam 19 from a first to a second position. Assuming that the movement of the cam 19 is to the left in Figure 1, the resultant movement of lever 21 results in a movement of the setting screw 24 to set the porting of the valve 9 so that hydraulic fluid is admitted to the left-hand side of the piston 8 and hydraulic fluid is exhausted to the reservoir 11 from the opposite side of the piston 8, so that the cylinder 6 and thereby the carriage 2 are driven in the same direction as the cam 19. The speed of movement is determined by setting of the restrictor 12, this speed being constant irrespective of and lower than the speed of displacement of the cam 19,assuming the latter is above a given speed, namely the speed of movement of the cylinder 6 as dictated by the setting of restrictor 12. When the roller 22 reaches the start of the camming surface 23, the valve 9 will start to be returned to its neutral position under the influence of its return spring or other returning influence until, with the roller 22 approximately halfway along the camming surface 23, the ports of the valve 9 are closed and thus the carriage stops. Similarly, movement of the cam 19 in the opposite direction (to the right in Figure 1) will cause the valve to port the supply to and return from the cylinder 6 in the opposite manner to the above, so that the carriage will again follow the direction of movement of the cam 19 at a constant speed irrespective of and lower than the speed of displacement of the cam 19 assuming the latter is above the said given speed, until the roller 22 regains a position approximately halfway along the camming surface 23.
[0015] Movement of the carriage 2 causes a pivotal movement of the lever 35 as a result of movement of the cam 34 relative to the roller 37, and a linear movement of the lever 25. As a result of this, the engine speed and pitch of the propeller respectively are taken to settings as determined by the position to which the cam 19 is displaced, at rates irrespective of the speed of displacement of the cam 19 if the latter is above the said given speed. Thus, the lever on the bridge may be moved from one command position to another as rapidly as may be desired without any detrimental effects on the control of engine speed and propeller pitch setting. For example,the lever on the bridge may be moved rapidly from "Full Ahead" to "Half Astern", resulting from which the lever 25, at a predetermined rate, will cause the propeller pitch setting mechanism to cause movement from Full Ahead pitch through Zero pitch to the Half Astern pitch, whilst at the same time, again at a predetermined rate, the lever 35 will correspondingly cause reduction in engine speed from full, through low, and then up to the required speed level for Half Astern .
[0016] In the event of an engine overload requiring a reduction in propeller pitch, oil is applied to cylinders 31 via lines 32 to move piston rods 33 inwards towards the lever 25. If the carriage 2 is still moving and the lever 25 is at a position such that a reduction in propeller pitch is necessary having regard to the overload, the lever 25 is pushed back, continuing movement of the carriage being accommodated by pivoting .of lever 25 against the action of spring 28. If the carriage 2 has stopped when an overload causes pistons 33 to move inwards and the lever 25 is at a position such that a reduction in propeller pitch is necessary, lever 25 is forced back with the carriage still stationary, pivoting against the action of spring 28. Also, the arrangement comprising cylinder 27, spring 28 and flanges 29 serves to avoid transmitting an unacceptably high force to the pitch setting mechanism - if this force exceeds a predetermined level, the spring 28 will be compressed between the flanges 29, lever 25 pivoting and the excess force being taken up by the spring 28.
[0017] The above example may be modified for controlling, instead of a controllable pitch propeller, a reversing gearbox for the engine, as well as engine speed. In this case, items 25 to 33 are omitted, and two cams mounted on top of the carriage 2, in a staggered relationship and one behind the other, namely cams 39 and 40 in Figure 3. A lever 41 is pivotally attached to the frame 1 and has an arm 42 which has a roller 43 which co-operates with the cam 39; and an arm 44 which has a roller 45 which co-operates with the cam 40. The pivotal connection of the lever 41 is via a cylindrical portion 46 and rods 47 and 48 fixed to the frame 1 and parallel to shafts 3 and 4 provide a support for the pivotal mounting. One end of a cable 49 is pivotally connected to the lever 41, its other end being connected to the control of a reversing gearbox. The operation of this example as regards engine speed is as in the previous example. As regards control of the reversing gearbox, movement of the carriage 2 causes a corresponding linear movement of the cams 39 and 40 and thereby a pivotal movement of the lever 41 to control the gearbox via cable 49. The arrangement must be such as to give time for the engine speed to reduce to a satisfactory low level during gearbox clutch disengagement and engagement and to increase engine speed setting at a rate suitable for the engine. The cams 39 and 40 are such that lever 41 is set in its mid-position with the carriage 2 at half stroke. The lever 41 is moved rapidly to full movement one way or the other over a relatively short travel of the carriage in either direction from its mid-position to cause Ahead or Astern engagement at low engine speed, further movement causing cam 34 to cause movement of the lever 35 progressively towards higher speed settings. Again, as the carriage 2 moves at a constant speed irrespective of the speed of movement of the cam 19 if the latter is above the said given speed, the lever on the bridge may be moved from one setting to another as quickly as desired.
[0018] Figure 4 is a perspective view showing the layout of part of a practical form of either of the above examples, certain components having been omitted for the sake of clarity and frame I only being shown in part. In this figure, reference 50 designates a screw for setting the amount of restriction of the restrictor 12 of the valve 9 and thereby the speed of movement of the carriage 2; and references 51 and 52 designate openings in the frame 1 for the flexible lines 15 and 16 to the reservoir 11 and the pump 10. The remaining reference numerals have the same significances as they do in the preceding figures.
[0019] The examples have the following advantages. Each arrangement is such that the carriage 2 moves at a constant speed irrespective of and lower than that of the speed of movement of the cam 19 if the latter is above a given speed, namely that dictated by the restrictor 12. The cam 19 merely causes actuation of a valve and therefore the force required for causing- movement of the carriage 2 is small.
[0020] Various modifications may be made to the above examples, for example as follows. The cylinder 6 could be static, the outer end of the piston rod 7 driving the carriage 2. The lever 35 could be mounted pivotally on the carriage, the cam 34 being fixed to the frame, and the lever 41 could be pivotally connected to the carriage 2, the cams 39 and 40 being fixed to the frame. The cylinders 31 and pistons 33 may be replaced by other means having the same function; as can the cylinder 29, spring 28 and flanges 29. Also,any of the cables 20, 30 and 49 could be replaced by a control rod or equivalent.
[0021] Also, in order to provide for an extra increase in speed, additional to that provided for by displacement of bell-crank lever 35 by cam 34, means may be provided for displacing further the lever 35 independently of action by the cam 34, by lowering the pivot axis of lever 35. One way in which this could be carried out is shown in Figures 5 and 6, in which certain items from Figures 1 and 2 have been omitted for the sake of clarity. The lever 35 is formed with a cylindrical extension 53 at right angles to it which extension is received over a bush 54 having two projecting arms 55 and 56. The bush 54 is eccentrically mounted on a pivot pin 57 having a head 58, the pin 57 being fixed to the frame 1 and there being a plate 59 for retaining the lever 35 on the bush 54, the plate 59 being held on the pin 57 by a screw 60. The bush 54 may be rotated in a clockwise direction in Figure 6,against the action of a return spring 61 fixed at one end to the arm 56 on a pin 62,by the piston rod 63 at a hydraulic cylinder 64 fixed to the frame I , the piston rod 63 being pivotally connected to the arm 55. In normal operation, the bush 54 is stationary and the lever 35 is displaced by the cam 34 and pivots around the bush 54. To provide an extra, rapid increase in speed, oil is supplied to the hydraulic cylinder 64 to move the piston rod 63 from left to right in Figure6 , thereby rotating bush 54 clockwise and lowering the pivot axis of lever 35, to provide the longer arm thereof with a further movement, independently of the operation of the cam 34. The flow of hydraulic oil to the cylinder 64 is initiated by a solenoid valve and a remotely operated switch to effect the speed increase. Instead of a hydraulic cylinder for causing rotation of the bush 54, other means - mechanical, electrical or pneumatic - could be used. Reference numerals 65 denote adjustable stop devices for limiting the amount of rotational movement of the bush 54.
1. A control arrangement for producing motion characterised in that it comprises:
first means (19), which can be displaced to any one of a plurality of positions at any one of a plurality of speeds:
a fluid-operated cylinder (6) and piston (8);
second means (21, 22, 9), arranged to be responsive to the position of the first means and to be actuated in response to displacement of the first means (19) from a first to a second position, in use of the arrangement, to trigger relative displacement between the cylinder (6) and piston (8) at a substantially constant speed less than that of displacement of the first means (19) if the speed of displacement of the first means (19) is greater than a given speed, until the second means responds to the second position ofthe first means (19); and
third means (2, 34, 35 and 25; or 2, 34, 35, 39, 10 and 41) displaced as a result of relative displacement between the cylinder (6) and piston (8).
2. An arrangement according to claim 1, characterised in that the said second means
comprises follower means (21, 22) for co-operating with the first means (19) and a
valve (9) controlled by the follower means (21, 22) for controlling the supply of
fluid to the said cylinder (6).
3. An arrangement according to claim 2, characterised in that the said valve (9) is
provided with means (12) for adjusting the rate of flow of fluid, for adjusting the
speed of relative displacement between the cylinder (6) and piston (8).
4. An arrangement according to any preceding claim, characterised in that the said
third means includes an actuating lever (35) provided with an associated cam (34)
which co-operates with it.
5. An arrangement according to claim 4, characterised in that the said third means
further includes a carriage (2) which is displaced relative to a frame (1) as a result
of relative displacement between the cylinder (6) and piston (8), the said lever (35)
being pivotally mounted on either the frame (1) or the carriage (2) and the associated
cam (34) being mounted on the other of the frame (1) and the carriage (2).
6. An arrangement according to claim 5, characterised in that the third means further
includes a further actuating lever (25), carried by the said carriage (2).
7. An arrangement according to claim 6, characterised in that it includes fourth means
(26 to 29), for normally preventing pivoting of the further actuating lever (25) during
displacement of the carriage (1).
8. An arrangement according to claim 7, characterised in that it includes pushing
means (31, 32 and 33) for pivoting back the further actuating lever (25) in response
to an overload.
9. An arrangement according to claim 7 or 8, characterised in that the fourth means
(26 to 29) is arranged for accommodating excessive force applied by the further actuating
lever (25).
10. An arrangement according to claim 5, characterised in that the said third means
further includes a further actuating lever (41) provided with an associated cam (39,
40) which co-operates with it, the further lever (41) being pivotally mounted on either
the carriage (2) or the frame (1) and the associated cam (39, 40) being mounted on
the other of the carriage (2) and the frame (1).