CONTROL ARRANGEMENT

Abstract: There is disclosed a control arrangement for a trolley (11) having a handle (21) by which a driving motor (17) is controlled, the handle (21) working a transducer (22) providing control signalling for said motor (17) and having limited movement relative to the trolley (11) in the fore and aft direction (23) but being stiffly connected to the trolley (11) in the vertical (24) and lateral (25) directions whereby the trolley (11) can be manually controlled by the handle (21) in pitch and yaw, in which the transducer (22) comprises a switch biased to one of two (on/off) positions which on operation of the handle to pull the trolley (11) along actuates a controller (19) to ramp up motor voltage in a predetermined fashion and when the switch returns under its bias to its position indicating lack of demand for further acceleration actuates the controller (19) to ramp down the motor voltage.

Description: CONTROL ARRANGEMENT This invention relates to control arrangement particularly for trolleys, more particularly for two- or three-wheeled, motorised trolleys such as golf trolleys or caddies. Numerous arrangements have been proposed, and some of them realised, for the control of motorised trolleys, by which is meant motorised vehicles which move at walking pace, controlled by a pedestrian. GB-A-2 285 852 describes a control arrangement for a trolley having a handle by which a driving motor is controlled, the handle having a transducer providing a control signal for the driving motor and having limited movement relative to the fore-and-aft direction, but being stiffly connected to the trolley in the vertical and lateral directions whereby the trolley can be manually controlled by the handle in pitch and yaw, essentially to steer it and to control its attitude for example so as to elevate it from a tilted, parked position, in the case of a two-wheeled trolley. The present invention provides control arrangements improved over those described in GB-A-2 285 852 which can be realised less expensively and which can be set up to maximise range through efficient power management. The invention comprises a control arrangement for a trolley having a handle by w hich a driving motor is controlled, the handle working a transducer providing control signalling for said motor and having limited movement relative to the trolley in the fore and aft direction but being stiffly connected to the trollev in the vertical and lateral directions whereby the trolley can be manually controlled by the handle in pitch and yaw, in which the transducer comprises a switch biassed to one of two or three positions which on operation of the handle to move or push the trolley along actuates a controller to ramp up motor voltage in a predetermined fashion and when the switch returns under its bias to its position indicating lack of demand for fuπher acceleration actuates the controller to ramp down the motor voltage. The trolley may be arranged to be just pulled or just pushed, in which case a two-position switch having on and off states may be used. However the trolley may be arranged to be pulled or pushed at will in which case a three-position switch arrangement biassed to the centre position could be used. Such three position switch arrangement could be constituted by two opposed micro switches. The operation of the switch with the trolley at rest may first remove a motor shunt, and may be arranged to produce an initial steep ramp adapted to overcome drive train friction - this can pres ent any perceivable delay in starting off from rest. The initial steep ramp may continue up to a threshold voltage at which a less steep ramp is effected by continued demand for acceleration. Ramping up and down may be effected at different rates - ramping down may be effected at a faster rate than ramping up (except if appropriate, for ramping up at an initial steep rate). After ramping down a motor shunt may be progressively brought into play to effect motor braking. On actuation of the switch to ramp up motor voltage any motor shunt applied may be immediately removed. A pre-set run control may be provided operable to ramp the motor voltage up to a predetermined value for a predetermined time. More than one predetermined time may be available. The arrangement may comprise a push-button type actuator independent of the handle switch to control the feature; one depression of the actuator might give a run-on time of. say. ten seconds, a second depression within. say. one second, could give a run-on time of. say. twenty seconds. Such a pre-set run control may be arranged to be operable only when the motor voltage is not otherwise being ramped up. A cruise control arrangement may be provided in which the instantaneous voltage applied to the motor can be maintained indefinitely. The cruise control may be arranged to be operative only when the motor voltage is being ramped up. thus when the trolley is accelerating under the control of the handle switch and has been thought to have attained a desired speed, the operating mode may be shifted into cruise so that the motor no longer responds to the handle switch. Again, a push-button type actuator may be used to select cruise mode. and. since cruise mode cannot be selected at the same time as pre-set run mode, the same push-button type actuator may be used for both controls, also to cancel cruise mode. The control arrangement may comprise a microprocessor. The pre¬ determined settings, e.g. of ramp rates, threshold voltage, pre-set run voltage and cruise speed, may be held in ROM having been specifically chosen to optimise performance of a particular trolley, or may be held in EEPROM with facility to change them, or some of them, according to user preference. Motor current can. of course, be monitored for protection from short circuit or to switch off in case of out-of-limits operation - a collision, for example. A current limiting arrangement can be provided preventing too-rapid acceleration or limiting uphill speed to improve the efficiency of the battery discharge cycle and to limit motor operation to its maximum efficiency range. The microprocessor can also monitor batter level and indicate charge remaining. The invention also comprises a trolley comprising a control arrangement as referred to above. With the motor braking feature, the motor may drive a fixed wheel arrangement; if a pair of fixed wheels is driven a differential may be used. Embodiments of a control arrangement and a trolley according to the invention will now be described with reference to the accompanying drawings, in which:- Figure 1 is a side elevation of a motorised golf trolley; Figure 2 is a cross-section through one embodiment of handle of the trolley of Figure 1 : Figure 3 is a cross-section through a second embodiment of handle of the trollev of Figure 1 : Figure 4 is a diagrammatic illustration of a control circuit; and Figure 5 is a set of graphs showing motor voltage against time in various operating modes. The drawings illustrate a control arrangement for a golf trolley 1 1. The trolley has a frame 12 with accommodation for a golf bag 13 and runs on wheels 14 on an a le 15 which comprises two half shafts with a differential. A foot 16 allows the trolley 1 1 to stand up when not in motion. An electric motor 17 drives the wheels which in this case are fixed wheels, i.e. without free wheel gear. A batten 18 powers the motor 17 under the control of the control arrangement 19. Instead of the foot 16, which normally requires the trolley to be tilted for movement, a third (free) wheel can be provided, or the third wheel can be driven by the motor while the other two coaxial wheels are free running. The trolley 1 1 has a handle 21 by which the motor 17 is controlled. The handle 21 works a transducer 22 providing control signalling for the motor 17 and having limited movement relative to the trolley 1 1 in the fore and aft direction, arrow 23, but is stiffly connected to the trolley in the vertical and lateral directions 24. 25. When the handle 21 is pulled in the usual fashion for pulling along an unmotorised trolley, the transducer 22 provides control signalling for the motor 17 which drives the wheels 14 reducing or eliminating the pulling force required to move the trollev 1 1. Pitch and vaw r control remains exactlv as it is with unmotorised trollevs. the handle 21 being, for these movements, the equivalent of the conventional unmotorised trolley handle. The handle 21 can. of course, simply be added on to or substituted for the existing handles of conventionally motorised trolleys to retrofit the control arrangement of the present invention. The transducer 22. in the handle illustrated in Figure 2. comprises a microswitch biassed to one of two (on/off) positions which on operation of the handle 21 to pull the trolley 1 1 along actuates the controller 19 to ramp up motor voltage in a predetermined fashion and when the micro switch returns under its bias to its position indicating lack of demand for further acceleration actuates the controller to hold the motor voltage for a predetermined time, then unless there is further demand, to ramp it down. The "'predetermined fashion " and "predetermined time " referred to depend on the circumstances. If the trolley 1 1 is at rest, operation of the micro switch 22 first removes a motor shunt - as seen in Figure 4. a rheostat 27 is connected across the motor 17 terminals and at rest the motor is shunted out with the slider at end "A " . To remove the shunt, the slider is moved to end "'B' * . (Of course, this can perhaps better be implemented with solid state switching in practice). The initial ramp from rest is very steep as seen at Rl on Figure 5. graph I. This is adapted to overcome drive train friction and reduce or eliminate any apparent delay between pulling on the handle and the trolley starting forward. This steep ramp - the slope of which can. of course, be selected at an appropriate value by trial on different types and weights of trolley - continues up to a threshold voltage V τ at which a less steep ramp R2 is effected by continued demand for acceleration. When the trolley 1 1 has accelerated to walking speed the pull on the handle 21 relaxes and the micro switch 22 returns under its bias. This maintains the voltage at the instantaneous level for a pre set time and then ramps the voltage down with a slope R3 steeper than R2. In prolonged walking, the slight slowing down of the trolley 1 1 will cause the micro switch 22 again to actuate the ramping up and down in cycles as shown in graph I of Figure 5. Appropriate selection of ramping rates and the hold level time, depending on the type and weight of the trolley can reduce or eliminate " 'hunting " here. Figure 3 illustrates a handle in which two opposed micro switches 31. 32 are used in a handle which effects appropriately directioned motor drive according as pulling or pushing the trolley is intended. The micro switches are fixed to the handle outer shell 33 and bear against faces 31 a. 32a of an armature 34 fixed to the trolley 1 1. The outer shell is supported on the armature 34 by rubber suspension collars 35. The arrangement (as also with the embodiment of Figure 2) is such that a light force in the appropriate direction will close the respective switch after slight movement, but that further force on the handle will not be taken by the switch mounting er se but rather bv stiffness in the handle mounting or by abutment means. After ramping down, the motor shunt can be progressively brought into play to effect motor braking - the use of motor braking implies, of course, the use of fixed rather than free wheels, hence the desirability of the differential in the drive train. Ramping down can be continued below zero volts so that enhanced motor braking can be used. The braking can be arranged to be regenerative so as to enhance range or time between batten' charges. If, of course, during a braking phase, the micro switch 22 is actuated to ramp up motor voltage again, indicating a demand for acceleration, the motor shunt is instantaneously removed. The handle 21 has a second switch 28 which is a push-button type switch in the end of the handle 21. This can be operated independently of the switch 22 and has different operational modes depending on the circumstances in which it is operated. If the switch 28 is operated when the motor voltage is not already being ramped up (e.g. from a standing start or during braking) it acts as a pre-set run control and it ramps the motor voltage up to a predetermined value V p and holds it for a predetermined time T P as shown in Figure 5, graph II. Two pushes on the button 28 can double this time - broken line trace in graph II. If the button 28 is pressed when the motor voltage is. under the pull or push control, greater than zero (otherwise than by actuation of the button 28) it acts as a cruise control in which the instantaneous voltage applied to the motor 17 is maintained indefinitely, until cancelled by another press on the button 28. This is seen in graph III of Figure 5. where the button 28 is pressed during an R2 ramp at time T c and again at T C D where D is the cruise duration. The controller 19 is based on a microprocessor 26 with either ROM or EEPROM 28 to hold the various parameters determining the ramp rates and timings. The microprocessor 26 can also be arranged to monitor battery charge level to indicate the same in red and green led ' s 29,30, and motor current and to impose a limit on motor current and cut off the power in defined out-of-limits operating conditions. Reverse apparatus (i.e. both push or pull operations from a single switch as shown in Figure 3) is illustrated diagrammatically by a change over switch 32 in Figure 4 - in practice, again, solid state switching under the control of the microprocessor 26 would be preferentially used, but the change over switch illustrates the intention. Implementation in programming of the microprocessor 26. of course, can give different drive characteristics according as the trolley 1 1 is pushed or pulled, should this be desired.

Claims: CLAIMS 1. A control arrangement for a trolley having a handle by which a driving motor is controlled, the handle working a transducer providing control signalling for said motor and having limited movement relative to the trolley in the fore and aft direction but being stiffly connected to the trolley in the vertical and lateral directions whereby the trolley can be manually controlled by the handle in pitch and yaw, in which the transducer comprises a switched biassed to one of two (on/off) positions which on operation of the handle to pull the trolley along actuates a controller to ramp up motor voltage in a predetermined fashion and when the switch returns under its bias to its position indicating lack of demand for further acceleration actuates the controller to ramp down the motor voltage. 2. A control arrangement according to claim 1. in which operation of the switch with the trolley at rest first removes a motor shunt. 3. A control arrangement according to claim 1 or claim 2. in which operation of the switch with the trolley at rest produces an initial steep ramp adapted to overcome drive train friction. 4. A control arrangement according to claim 2, in which the initial steep ramp continues up to a threshold voltage at which a less steep ramp is effected by continued demand for acceleration. 5. A control arrangement according to any one of claims 1 to 4, in which ramping up and down are effected at different rates. 6. A control arrangement according to claim 5. in which ramping down is effected at a faster rate than ramping up (except, if appropriate, for ramping up at an initial steep rate). 7. A control arrangement according to any one of claims 1 to 6. in which during ramping down a motor shunt is progressively brought into play to effect motor braking. 8. A control arrangement according to claim 7, in which on actuation of the switch to ramp up motor voltage any motor shunt applied is immediately removed. 9. A control arrangement according to any one of claims 1 to 8. in which a pre¬ set run control is provided operable to ramp the motor voltage up to a predetermined value for a predetermined time. 10. A control arrangement according to claim 9. in which said pre-set run control is operable to maintain said predetermined value for more than one predetermined time. 1 1. A control arrangement according to claim 9 or claim 10. comprising a push¬ button type actuator independent of the handle switch. 12. A control arrangement according to any one of claims 9 to 1 1. in which the pre-set run control is operable only when the motor voltage is not being otherwise ramped up. 13. A control arrangement according to any one of claims 1 to 12. comprising a cruise control arrangement in which the instantaneous voltage applied to the motor can be maintained indefinitely. 14. A control arrangement according to claim 13. in which the cruise control arrangement is operative only when the motor voltage is being ramped up. 15. A control arrangement according to claim 12 or claim 13. comprising a push-button type actuator independent of the handle switch. 16. A control arrangement according to claim 15. in which the push-button type actuator is the actuator referred to in claim 1 1. 17. A control arrangement according to any one of claims 1 to 16, comprising a microprocessor. 18. A control arrangement according to claim 17. in which pre-determined settings are held in ROM. 19. A control arrangement according to claim 18, in which the ROM comprises EEPROM. 20. A trolley comprising a control arrangement according to any one of claims 1 to 19. 21. A trolley according to claim 20, in which the motor drives a fixed wheel arrangement. 22. A trolley according to claim 21. in which the trolley drives a pair of fixed wheels via a differential.

Inventors: HANCOCK FRANK JOHN THOMPSON, HANCOCK, FRANK, JOHN, THOMPSON
Applicants: HANCOCK FRANK JOHN THOMPSON, HANCOCK, FRANK, JOHN, THOMPSON
Application year: 1997
Main classification: B60L15
IPC codes: B60L7, B60L15, B62B5