WO1992010383A1

WO1992010383A1 - Speed management device

Info

Publication number: WO1992010383A1
Application number: PCT/AU1991/000577
Authority: WO
Inventors: Graeme Richard Payne
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-12-12
Filing date: 1991-12-12
Publication date: 1992-06-25
Anticipated expiration: 1993-06-12

Abstract

A speed management device for limiting a motor vehicle to a predetermined speed comprising an apparatus for interfacing a throttle with a control therefor. The apparatus comprises a linkage including a solenoid (143) for selectively connecting and disconnecting the throttle from the control, and a sensing means in the form of a microswitch (151) to sense a relative position at which the solenoid (143) may operate to latch the linkage. The apparatus includes a circuit (173) for operating the solenoid (143), and controlling a servo (127) which controls the throttle to maintain the predetermined speed while the linkage disconnects the throttle from the control. Instantaneous speed information is derived by the circuit (173) from a speed sensor (175), and the predetermined speed is selected on a selector arrangement (177). An option switch (179) is provided to enable or disable the function of the device, and to select other functions that the device may optionally possess. The device functions by operating the solenoid (143) when the circuit (173) determines that the predetermined speed has been reached, and overrides control of the throttle from the driver until the driver desires to slow the vehicle, at which point the circuit (173) senses the relative position and deactuates the solenoid (143) to restore control of the vehicle speed to the driver. An 'impact drive' bistable solenoid is also disclosed.

Description

"SPEED MANAGEMENT DEVICE"

THIS INVENTION relates to a speed management device for managing and inter alia limiting speed of motor vehicles and an apparatus for limiting the maximum speed, of vehicles to a presettable maximum.

In this patent specification- the term "throttle actuator" is defined as including a mechanical control which actuates a butterfly valve in a carburettor, a mechanical control equivalently used in fuel injection, a speed control for an electric motor, or the like; the term "operable control" is defined as including a pedal, lever, twist or other control for operation by a person or other means to effect control over the throttle actuator; and the term "motor" is defined as including a motor or engine, or a motor vehicle.

Hitherto, known devices for controlling the speed of a motor vehicle, commonly known as a "cruise control" or "cruise control devices" have been available. These devices operate by effecting overriding control of a motor vehicle throttle or accelerator pedal, and by means of negative feedback, adjusting a servo to control the throttle setting of the engine of the motor vehicle, in order to maintain a certain speed. These cruise control devices may be selected voluntarily by the driver of the motor vehicle, in order to maintain the speed of the vehicle, usually at the speed at which the cruise control device has been activated. Whilst these cruise control devices can effect control of the speed of the motor vehicle, they can not effect control as a speed limiting device, as will be seen in the case of the present invention. Indeed, the known cruise control devices may be overridden or even selected to maintain a motor vehicle speed which is well above a legal speed limit. In addition, whilst many responsible drivers use the known speed control devices in order to avoid exceeding a gazetted speed limit, a moments inattention resulting in overlooking the act of activating the _ cruise control device, may result in a gazetted speed limit being unintentionally exceeded.

There are known speed limiting devices which rely on cutting off flow of fuel to or interrupting ignition of an internal combustion engine, but these suffer from the problems of being unsmooth in operation.

These and other disadvantages may be obviated by the use of an apparatus embodying the present invention, described hereafter.

In accordance with one aspect of the present invention there is provided a throttle actuating means for interfacing an operable control and a throttle actuator, said throttle actuating means including a first member cooperating with a second member, a mechanism for cooperating with said first member and said second member, and sensing means associated with said members adapted to sense a relative position of said members corresponding to a relative rest position of said members, said first member being adapted for connection to said operable control and said second member being adapted for connection to said throttle actuator, said mechanism being selectable between a first condition and a second condition when said members are in said relative rest position, wherein in said first condition said mechanism locks said first member and said second member together, and in said second condition said mechanism unlocks said first member from said second member for relative independent movement in relation to each other.

Preferably said sensing means includes a switching means cooperating with said throttle actuating means.

Preferably said switching means includes a proximity switch mechanism, a hall effect sensor arrangement, or a light beam sensor arrangement.

Preferably said first member and said second member are mounted for rotational movement coaxial with said throttle actuator.

Preferably said first member and said second member ar.e mounted for linear sliding movement in relation to each other when said mechanism is in said second condition.

Preferably said mechanism comprises an electrically operated solenoid arrangement.

Preferably said electrically operated arrangement is mounted remotely from said first member and said second member.

Preferably said electrically operated solenoid arrangement comprises a solenoid having an electromagnetic coil and a plunger moveable along a central axis between an extended position corresponding to said first condition and a retracted position corresponding to said second condition, and biased toward said extended position, and having a magnet core slidably mounted on said plunger moveable between a proximal position located toward said extended position and a stop located on said plunger at a point located away from said extended position and located relatively toward said electromagnetic coil.

Preferably said magnet core is biased on said plunger toward said proximal point. Preferably electrically operated solenoid arrangement includes a second solenoid associated with said solenoid, adapted to selectively hold said plunger in said retracted position, said second solenoid having a second plunger mounted normally to said plunger and biased toward a second extended position in which it is adapted to interfere with said plunger in said retracted position to retain said plunger thereat, and actuable to a second retracted position to release said plunger.

Preferably said throttle actuating means includes means for limiting shear forces applied at said mechanism by said first and second members.

Preferably said means for limiting comprises a resilient connection between . said second member and said throttle actuator.

In accordance with another aspect of the present invention there is provided a speed management device for limiting the speed of a motor to a predetermined maximum speed comprising an apparatus for interfacing a throttle actuator with an operable control, said apparatus comprising a throttle actuating means as hereinbefore described and a control means, said mechanism being provided for selectively connecting and disconnecting said throttle actuator from said operable control and said sensing means being adapted to sense a relative position at which said mechanism may operate to connect said throttle actuator to said operable control, said control means including a first control means for selectively operating said mechanism, a second control means for selectively controlling said throttle actuator, and detection means for detecting instantaneous motor speed; wherein said control means is adapted to allow said operable control to actuate said throttle actuator until said control means detects that said predetermined maximum speed has been reached or exceeded, whereupon said control means is adapted to actuate said mechanism to disconnect, said operable control from said throttle actuator, and is adapted to control said throttle actuator to substant ally maintain said predetermined maximum speed.

Preferably said control means is adapted to actuate said mechanism to disconnect said operable control from said throttle actuator at a speed exceeding said predetermined maximum speed and thereafter said control means is adapted to control said throttle actuator to substantially maintain said predetermined maximum speed.

Preferably said control means is adapted to actuate said mechanism to reconnect said operable control to said throttle actuator when said sensing means senses said relative position whilst said predetermined maximum speed is substantially maintained. This may be achieved by partially releasing said operable control to a position corresponding to said predetermined maximum speed as maintained by said control means.

Preferably said control means is adapted to release control of said throttle actuator when said sensing means senses said relative position whilst said predetermined maximum speed is substantially maintained, restoring control to the operator thereof.

Preferably said control means also includes brake sense means for sensing overriding control to slow said motor and is adapted to maintain said predetermined maximum speed when said sensing means senses said relative condition; wherein while said predetermined maximum speed is substantially maintained and upon said brake sense means sensing said overriding control, said control means is adapted to release control of said throttle actuator, to restore control to the operator thereof.

In this manner, in a motor vehicle application, whilst said predetermined maximum speed is substantially maintained, upon releasing said operable control said control means continues to maintain said predetermined maximum speed until the operator operates the brake _r whereupon normal control is resumed and the vehicle may be slowed or accelerated until said control means again resumes control.

Preferably said first condition is adapted to be selected at a motor operating speed less than said predetermined maximum speed, and said second condition is adapted to be selected at a motor operating speed substantially equal to or exceeding said predetermined maximum speed.

The invention will be better understood by reference to the following description of four specific embodiments thereof, in whic :-

Figure 1 is a part view of a mechanical schematic diagram of a throttle linkage arrangement for a vehicle speed limiting device according to the first embodiment;

Figure 2 is a schematic diagram of a throttle linkage arrangement for a vehicle speed limiting device according to the first embodiment;

Figure 3 is an electrical schematic diagram of a vehicle speed limiting device according to the first embodiment;

Figure 4 is a side view of a part of a throttle linkage arrangement for a vehicle speed limiting device according to the second embodiment;

Figure 5 is a side view of a further part of a throttle linkage arrangement for a vehicle speed limiting device according to the second and third embodiments;

Figure 6 is a schematic diagram in pla,n view looking along A-A, of a throttle linkage arrangement for a vehicle speed limiting device according to the second and third embodiments;

Figure 7 is an electrical schematic diagram of a vehicle speed limiting device according to the second embodiment;

Figure 8 is an electrical schematic diagram of a vehicle speed limiting device and cruise control according to the third embodiment;

Figure 9 is a cross section view of a bistable solenoid described in relation to the embodiments, shown in the unactuated condition;

Figure 10 is a cross section view of a bistable solenoid described in relation to the embodiments, shown in the actuated condition;

Figure 11 is a plan view of a throttle linkage arrangement for a vehicle speed limiting device according to the fourth embodiment;

Figure 12 is a side elevation of the throttle linkage arrangement shown in figure 11 shown through section

A-A of figure 13;

Figure 13 is a front elevation of the throttle linkage arrangement shown in figure 11;

Figure 14 is a side elevation of the throttle actuating means shown in figure 11 shown through section A-A of figure 13; and

Figure 15 is a side elevation of the throttle actuating means shown in figure 11 shown through section A-A of figure 13.

The first embodiment is directed towards a speed limiting device for a motor vehicle, the mechanical aspects being shown in figures 1 and 2, the electrical aspects being shown in figure 3- A motor vehicle carburettor 11 is represented by a choke 13, a butterfly valve 15, and a spindle connector 17- A throttle actuator in. the form of a linkage 19 connects the butterfly valve 15 and the spindle connector 17 of the carburettor 11 to a throttle actuating means 21 at a pivot point 23.

A further linkage 25 (a servo linkage) is connected to a servo unit 27 by a cable 29. The cable 29 consists of a cable inner 31 and a cable jacket 33, secured against an abutment 35.

The throttle actuating means 21 has a first member 37 accommodated within a second member in the form of a tubular portion 39. The pivot point 23 is fixed to the outer surface of tubular portion 3S.

Tbe tubular portion 39 has an aperture 41 over which is mounted a mechanism in the form of a solenoid unit 43. The first member 37 has an aperture 45 for receiving the plunger 47 of the solenoid unit 43.

The plunger 47 of the solenoid unit 43 is held in extension by a spring 49 locking the first member 37 to the tubular portion 39 in a position defining a relative rest position. When power is applied to the electrical coil (not shown) of the solenoid unit 43, the magnetic field generated in the solenoid coil causes the plunger 47 to act against the spring 49 and withdraw into the solenoid unit, out of engagement with the aperture 45 in the first member 37. This results in the first member 37 and the tubular portion 39 being unlocked for relative independent movement.

The tubular portion 39 accommodates a microswitch 51 having a roller type actuator 53 extending through a further aperture 55 in the tubular portion 39. The roller of the actuator 53 of the microswitch 51 engages the first member 37 in proximity to a contoured step portion 57 thereof.

The throttle actuating means 2" has a stop 59 to limit the movement of the first member 37 within the tubular portion 39 so that the plunger 47 of the solenoid unit 43 lines up with the aperture 4.5 in the first member 37, when the first member 37 is at the relative rest position within the tubular portion.

The first member 37 is provided with an aperture 61 for accommodating a cable inner 63 of a cable (not shown) , the cable inner 63 links to an operable control such as an accelerator pedal. The cable inner 63 is secured within the first member 37 by a screw 65. A further abutment 67 is provided for securing the cable jacket (not shown) of the cable.

A coil spring 69, under tension (extended) , is provided for biasing the tubular portion 39, and hence the linkage 19, towards a position corresponding to a minimum throttle setting on the carburettor 11.

A coil spring 71, under tension (extended) , is provided for biasing the first member 37 towards the rest position within the tubular portion 39. In addition, the coil spring 71 consequently biases the operable control "accelerator pedal" towards an uppermost position, corresponding to a minimum throttle setting on a conventional engine throttle control system in a motor vehicle.

The solenoid unit 43, microswitch unit 51, and servo unit 27 are electrically connected to an electronic processor 73. The electronic processor 73 together with the servo unit 27 form a control means. The electronic processor 73 is additionally connected to a speed sensor in the form of a hall effect device 75. Associated with, the hall effect device 75.is -.a number of magnets affixed to the drive shaft of the vehicle. The hall effect device 75 will respond to the proximity of the magnets as they pass by, when the vehicle is in motion, and thus enable the electronic processor 73 to determine the road speed of the motor vehicle. It should be noted that other means of speed detection are suitable in the practise of the invention.

The processor is also connected to a selector switch 77, which enables the maximum speed to be selected, at which tbe vehicle speed limiting device will operate to limit the speed, of the motor vehicle.

The operation of the motor vehicle speed limiting device will now be described. At speeds below the selected maximum speed as selected on the selector switch 77, the plunger 47 of the solenoid unit 43 will be accommodated within the aperture 45 in the first member 37. As a consequence, the first member 37 will be at a rest position within the tubular portion 39, and the driver of the motor vehicle will have full control of the position of the linkage 19 through the operable control (accelerator pedal) actuating the cable inner 63. In this condition, the throttle actuating means 21 acts as a link in the normal vehicle throttle control linkage at the carburettor of the motor vehicle.

However, upon reaching the preset maximum speed and trying to exceed that speed, the electronic processor 73, by determining the vehicle speed from the signals from the hall effect device 75 and comparing it with the signal derived from the selector switch 77, will determine that the selected maximum speed has been exceeded. Consequently, a signal will be sent to the solenoid unit 43 and the plunger 47 of the solenoid unit 43 will be withdrawn from the aperture 45 in the .first member. Simultaneously, the electronic processor 73 provides a signal to the servo unit, and utilising instantaneous speed information determined from signals from the hall effect device 75 controls tbe position of the servo unit 27 to maintain the speed of the motor vehicle, in much the same manner as a typical servo unit in a cruise control device does. If the vehicle encounters a change in gradient of the road, the electronic processor 73 will detect the slight change in vehicle speed and cause the servo unit 27 to make appropriate adjustments to the throttle setting of the motor vehicle, in order to maintain the selected speed.

At the point in which the solenoid unit 43 is actuated, causing the plunger 47 to withdraw from the aperture 45 in the first member 37, the first member 37 will be caused to slide within the tubular portion 39, away from the stop position determined by the stop 59. As a result of this, the roller type actuator, traversing the step portion 57 will cause the microswitch 51 to switch over. An alternative manner of controlling the icroswitches sensing of the relative rest position will be described with reference to the second embodiment.

Any further depression of the operable control (accelerator pedal of the motor vehicle) will cause the first member 37 to move slidably within, the tubular portion 39, further away from the rest position/stop position determined by the stop 59. Such further depression of the operable control will not effect the engine speed.

Upon release of the operable control (accelerator pedal of the motor vehicle) the coil spring 71 will retract the first member 37 into the tubular portion 39, towards the rest position, until the rest position and stop is reached. At this position, the contacts of the microswitch 51 will be thrown by the roller type actuator 53 _^traversing the step portion 57 of the first member 37. This change of state of the microswitch 51 contacts will be detected by the electronic processor 73 which will release the solenoid 43 and release the servo unit 27 from controlling the further linkage 25 of the vehicle throttle. Thus control of the vehicle speed will be restored to the operator, via the operable control (accelerator pedal) .

The embodiment of this invention is fitted with extra features, being intended to be selectively used by an operator, A further selector switch. 79 is provided whereby the driver of the motor vehicle can select operation of the unit between an off position 81, where the speed limiting device is disabled, a speed limit position 83 where the unit functions as hereinbefore described, and a cruise control position 85 where the unit functions as a cruise control. For use as a cruise control, a stop switch 87 is provided in association with the brake pedal of the motor vehicle, to disable the cruise control when the brake is applied. In addition, the microswitch 51 and the function of the solenoid unit 43 would be disabled. In addition, the electronic processor 73 includes cruise control function switches (not shown) which are typical to known cruise control units. Such switches include "set", "accelerate", "resume", "increase cruise speed", "decrease cruise speed", and "stop".

Various other embodiments can be envisaged from the aforesaid description. The embodiment described in this description is for use in a vehicle with a cable operated throttle system, where the cable pulls the throttle actuator. An alternative version could be built where the throttle actuator is pushed by a rod and linkage arrangement connected to the accelerator pedal. In this case, referring specifically to figure 2 the rod and linkage arrangement would link to the portion of the first member 37 which receives the spring 71. The spring 71 may need to be relocated or alternatively exchanged for a spring in compression located between the first member 37 and the further abutment 67, in order to bias the first member towards the rest position relative to the tubular portion 39.

The second embodiment is directed towards a speed limiting device for a motor vehicle, the mechanical aspects being shown in figures 4, 5 and 6, the electrical aspects being shown in figure 7.

A motor vehicle carburettor 111 is shown in figure 6 and being of dual choke construction, has two chokes 113, two butterfly valves 115, and a spindle connector 117. A throttle actuating means 121 connects directly to the spindle connector 117 of the carburettor 111.

The throttle actuating means 121 has a first arcuate member 137 and a second arcuate member 139.

The second arcuate member 139 is connected to a servo unit 127 by a cable 129. The cable 129 consists of a cable inner 131 and a cable jacket 133, secured against an abutment 135. The second arcuate member also has a pop- connector assembly 136, for connecting the cable inner 131.

The first arcuate member 137 has an aperture 141 around which is mounted an internally threaded sleeve, threaded for receiving a mechanism in the form of a solenoid unit 143. The second arcuate member 139 has an aperture 145 for receiving the plunger 147 of the solenoid unit 143. The movement of the plunger 147 through the aperture 145 is limited by a coverplate 148 (shown in hidden detail) .

When the plunger 147 of the solenoid unit _143 is held in extension, the first arcuate member 137 is locked to the second arcuate member 139 in a position defining a relative rest position. When power is applied to the electrical coil (not shown) of the solenoid unit 143, the magnetic field generated in the solenoid coil causes the plunger 147 to withdraw into the solenoid unit, out of engagement with the aperture 145 in the second arcuate member 139. This results in the first arcuate member 137 and second arcuate member 139 being unlocked for relative independent movement.

The second arcuate member 139 is connected to the spindle connector 117 through a mounting point 149 and is locked to the spindle connector for. relative rotational movement therewith. The first arcuate member 137 is mounted for rotation on the spindle connector 117 about a mounting point 150.

The second arcuate member 139 accommodates a microswitch 151 having an actuator 153, on a flange portion 155. The actuator 153 of the microswitch 151 engages the first arcuate member 137 and is depressed thereby, when the first arcuate member 137 and the second arcuate member 139 are in the relative rest position.

The flange portion 155 has a stop 159 to limit the movement of the first arcuate member 137 relative to the second arcuate member 139 so that the plunger 147 of the solenoid unit 143 lines up with the aperture 145 in the second arcuate member 139, when the first arcuate member 137 is at the relative rest condition.

The first arcuate member 137 is provided with a connector 161 for connecting a cable inner 163 of a cable jacket 164, the cable inner 163 links to an operable control such as an accelerator pedal. The cable inner 163 is secured to the first member 137 by a pop-connector 165. An abutment 167 is provided for securing the cable jacket (not shown) of the cable.

Coil springs 169, under tension (extended) , are provided for biasing the first arcuate member 137 and the second arcuate member 139 and hence the throttle actuating means towards a position corresponding to a minimum throttle setting on the carburettor 111.

The coil spring 169b, under tension (extended) , is provided for biasing the first arcuate member 137 towards the rest position relative to the second arcuate member 139. In addition, the coil spring 169b consequently biases the operable control (accelerator pedal) towards an uppermost position, corresponding to a minimum throttle setting on a conventional engine throttle control system in a motor vehicle.

The solenoid unit 143, microswitch 151, and servo unit 127 are electrically connected to an electronic processor 173. The electronic processor 173 together with the servo unit 127 form a control means.

The electronic processor 173 is additionally connected to a speed sensor in the form of a hall effect device 175. Associated with the hall effect device 175 is a number of magnets affixed to the drive shaft of the vehicle. The hall effect device 175 will respond to the proximity of the magnets as they pass by, when the vehicle is in motion, and thus enable the electronic processor 173 to determine the road speed of the motor vehicle. — X o

The processor is also connected to a selector switch 177.- which enables the maximum speed to be selected, at which the vehicle speed limiting device will operate to limit the speed of the motor vehicle.

The processor 173 is connected to a stop switch 187 provided in association with the brake pedal of the motor vehicle, the stop switch 187 defining brake sense means.

The operation of the motor vehicle speed limiting device of the second embodiment is similar to that described in the first embodiment. At speeds below the selected maximum speed as selected on the selector switch 177, the plunger 147 of the solenoid unit 143 will be accommodated within the aperture 145 in the second arcuate member 139. As a consequence, the first arcuate member 137 will be at a rest position relative to the second arcuate member 139, and the driver of the motor vehicle will have full control of the position of the butterfly valves 115 (and hence the throttle) through the operable control (accelerator pedal) actuating the cable inner 163. In this condition, the throttle actuating means 121 acts as a linkage in the normal vehicle throttle control linkage at the carburettor of the motor vehicle.

However, upon reaching the preset maximum speed and trying to exceed that speed, the electronic processor 173, by determining the vehicle speed from the signals from the hall effect device 175 and comparing it with the signal derived from the selector switch 177, will determine that the selected maximum speed has been exceeded. Consequently, a signal will be sent to the solenoid unit 143 and the plunger 147 of the solenoid unit 143 will be withdrawn from the aperture 145 in the second arcuate member 139. Simultaneously, the electronic processor 173 provides a signal to the servo unit 127, and utilising instantaneous speed information determined from signals from the hall effect device 175 controls the position of the servo unit 127 to maintain the speed of the motor- vehicle, in much the same manner as a typical servo unit in a cruise control device does. If the vehicle encounters a change in gradient of the road, the electronic processor 373 will detect the slight change in vehicle speed and cause the servo unit 127 to make appropriate adjustments to Lhe throttle setting of the motor vehicle, in order to maintain the selected speed.

Any further depression of the operable control (accelerator pedal of the motor vehicle) will cause the first arcuate member 137 to move relative to the second arcuate member 139, further away from the rest position/stop position determined by the stoχ> 159. Such further depression of the operable control will not effect the engine speed.

Upon release of the operable control (accelerator pedal of the motor vehicle) the coil spring 169b will retract the first arcuate member 137 towards the rest position, until the rest position and stop is reached. At this position, the contacts of the microswitch 151 will be thrown by the actuator 153. This change of state of the microswitch 151 contacts will be detected by the electronic processor 173 which will release the solenoid 143 and release the servo unit 127 from controlling the vehicle throttle. Thus control of the vehicle speed will be restored to the operator, via the operable control (accelerator pedal) .

At the point in which the solenoid unit 143 is actuated, causing the plunger 147 to withdraw from the aperture 145 in the second arcuate member 139, if the first arcuate member 137 has not moved relative to the second arcuate member 139, away from the stop position determined by the stop 159, the microswitch 151 will not have switched over. Two features are provided to ensure that this does not cause difficulty, as there is an inherent danger that if the driver released the accelerator pedal of the motor vehicle because in this instance there would be no change over of the contacts in the microswitch, and the driver's desire to slow the vehicle would not be transmitted to the electronic processor 173. Accordingly, tbe electronic processor 173 monitors the state of the microswitch 151, and, if there is no change of the state of the contacts of the microswitch 151 within a predetermined period after the solenoid unit 143 and the servo unit 127 have activated, for example between five milliseconds and one hundred milliseconds, the electronic processor 173 will restore control of the motor vehicle to the operator by releasing the solenoid 143 and releasing the servo unit 127 from controlling the vehicle throttle. Additionally, a stop switch 187 mechanically linked to the brake pedal is provided, so that in the event that the microswitch 151 has not swi-tched over, following the actuation of the solenoid to withdraw the plunger 147 from the aperture 145, and the driver wishes to slow the vehicle, the change of state of the switch 187 caused by applying the brakes will cause the solenoid 143 to release, and release the servo unit 127 from controlling the vehicle throttle, restoring control of the vehicle speed to the driver.

In order to avoid constant cycling of the speed limiter throttle actuating means in the situation where the predetermined maximum speed is reached and the microswitch contacts have not changed over, it is preferable to provide some hysteresis in the control means so that the solenoid is actuated and servo unit activated to control the throttle at a speed above, for example 3km/hr to 6km/hr above, the predetermined maximum speed, whereupon when the solenoid is actuated and the servo unit activated, the servo unit controls the throttle to reduce the vehicle speed down to the predetermined maximum speed, to ensure that the contacts of the microswitch open. The solenoid cannot be released to restore control c-f the vehicle throttle to the driver until the vehicle speed has fallen substantially to the predetermined maximum speed; however applying the brakes will restore control of the throttle to the driver,

The embodiment of this invention is fitted with extra features, being intended to be selectively used by an operator. A further selector switch 179 is provided whereby the driver of the motor vehicle can select operation of the unit between an off position 181, where the speed limiting device is disabled, a speed limit position 183 where the unit functions as hereinbefore described, and a cruise control position 185 where the unit functions as a cruise control for speeds up to the predetermined maximum speed and functions as a speed limiter as hereinbefore described. For use as a cruise control, the stop switch 187 provided in association with the brake pedal of the motor vehicle is also utilised to disable the cruise control function when the brake is applied. In addition, the electronic processor 173 includes cruise control function switches (not shown) which are typical to known cruise control units. Such switches include "set", "accelerate", "resume", "increase cruise speed", "decrease cruise speed", and "stop".

In addition and for convenience the "increase cruise speed" and "decrease cruise speed" switches can be included in the speed limiter to calibrate the predetermined maximum speed for synchronising the speed of the motor vehicle with other motor vehicles travelling on the same road.

The third embodiment is directed towards a combined speed limiting device and cruise control for a motor vehicle, the mechanical aspects being shown in figures 4, 5 and 6, tbe electrical aspects being shown in. figure 8. The structure of the mechanical aspects is the same as described in the second embodiment and will not be repeated.

The variation between the second and third embodiments is in the operation of the unit, and there is no selector switch for selecting between functions of cruise control and speed, limiter.

The operation of the motor vehicle combined speed limiting device and cruise control is similar to that described in the second embodiment except that when the predetermined maximum speed has been reached, and the solenoid unit 143 and servo unit 127 actuated, upon release of the operable control (accelerator) the first arcuate member 137 is retracted to the rest position and stop, and the contacts of the microswitch 151 are thrown by the actuator 153. The change of state of the microswitch contacts, upon detection by the electronic processor 173 results in the solenoid 143 being released, locking the first arcuate member 137 to the second arcuate member 139; however, the servo unit 127 continues to maintain the speed of the vehicle. In this condition the accelerator may be depressed to accelerate the vehicle beyond the preset maximum speed but upon release of the accelerator the preset maximum speed is resumed. The servo unit 127 is not disabled until the brake pedal is depressed, actuating the stop switch 187 and causing the electronic processor to release control of the servo unit, restoring full control of the vehicle speed to the operator.

The embodiment of this invention may be fitted with extra features, being intended to be selectively used by an operator. For convenience "increase cruise speed" and "decrease cruise speed" controls can be included in the combined speed limiting device and cruise control to calibrate the predetermined maximum speed for synchronising the speed of the motor vehicle with other .motor vehicles travelling on the same road.

In addition to the stop switch 187, a switch for cancelling the cruise control can be provided, wired in parallel to the contacts thereof. The actuation of such a "cancel switch" would have the same effect as actuating the stop switch 187. The "cancel switch" provided in this manner would inter alia provide a degree of margin for safety in the event of mechanical failure of tbe stop switch.

It should be understood that any of the operational features described in relation to the aforementioned embodiments could be combined in a new embodiment. Further operational features may be envisaged, having ascertained the invention, and are deemed to fall within the scope of the invention.

Referring to figures 9 and 10, a preferred arrangement for a solenoid unit 43 or 143 is shown. The solenoid unit 43/ 143 has a plunger 47/147 which is adapted to engage the aperture 45 in the first member 37, or aperture 145 in the first arcuate member 137, depending on the particular embodiment with which the solenoid unit 43 or 143 is used.

The solenoid unit 43/143 has a tubular outer casing 211 which has threads for threadingly engagement with a proximal end cap 213 at one end, and a distal end cap 215 mounted at the other end thereof. The proximal end cap 213 has an external male thread for securing to a fitting in either the tubular portion 39 or the second arcuate member 139, depending on the embodiment with which the solenoid unit is employed. The proximal end cap 213 has an aperture 217 through which the plunger 47/147 may protrude. The plunger 47/147 has a radial step 219, which provides a stop for limiting the external travel of the plunger 47/147 through the aperture 217. Located inside the outer casing 211, between the proximal end cap 213 and the distal end cap 215 is an electromagnetic coil 221 wound on a coil former 223. A proximal spacer 225 is located between the coil former 223 and the proximal end cap 213, A distal- spacer 227 is located between the coil former 223 and the distal end cap 215. Tbe distal spacer 227 has a central aperture for slidably receiving a centrally located spindle 231, and supports the spindle 231 for sliding movement along the central aperture 229. The spindle 231 threadingly engages the plunger 47/147 at the proximal end thereof, and threadingly engages a secondary plunger 233 at the distal end thereof.

The spindle 231 has an annular step 235 located at a point in proximity to the electromagnetic coil 221. The annular step 235 limits the movement of the spindle 231, and hence the plungers to which it is attached, in the various states of actuation of the solenoid unit.

A floating core 237 is slidably mounted on the spindle 231, and is moveable between the annular step 235 and the plunger 47/147. The floating core is biased in a direction away from the proximal spacer 225 by a compression spring 239 which acts against an annular step 240 located on the proximal end of the floating core 237. The compression spring 239 urges the floating core to contact the plunger 47/147, and urge the plunger to extend outwardly from the solenoid unit 43/143.

A further solenoid unit 241 is mounted on the distal end cap 215. The further solenoid unit 241 has a plunger 243 which includes a non ferromagnetic portion 244 which is biased in a direction towards the plunger 233 by a compression spring 245. The plunger 233 has an annular recess 247, which is adapted to receive the tip of the plunger 243, when the electromagnetic . coil 221 is energised. Referring to figure 10, the solenoid unit 43/143 is shown with the electromagnetic coil 221 in the energised condition.

On energising the electromagnetic coil 221 the floating core 237 is attracted towards the centre of the electromagnetic coil, causing it to slide in a direction, towards the distal end cap 215. The floating core 237, as it moves, attracted by the magnetic field of the electromagnetic coil 221, and moving against the resistance exerted by the compression spring 239, will contact the annular step 235 and cause the spindle to move towards the distal end of the solenoid unit. The advantage in having the floating core 237 lies in the fact that as the floating core will have built up some momentum before it contacts the annular step 235, it will provide a jarring effect to the central spindle, which is transmitted to the plunger 47/147, which will be more likely to overcome any sticking due to shear stresses imposed by external forces applied at the apertures 45 or 145.

When the spindle 231 and its plungers 47/147 and 233 are sufficiently withdrawn, whilst electromotive force remains applied to the electromagnetic coil 221, the annular recess 247 in the plunger 233 will become coincident with the plunger 243 of the further solenoid unit 241. When this occurs, the compression spring 245 will cause the tip of the plunger 243 to move into the annular recess 247 of the plunger 233. Accordingly, when electromotive force is removed from the electromagnetic coil 221, the spindle 231 and its plungers 47/147 and 233 will remain in the withdrawn position, retained by the interference of the tip of plunger 243 with the annular recess 247 in the plunger portion 233 .

The annular step 235 is configured in such a .manner that it is received between the floating core 237 and the distal spacer 227, when the electromagnetic coil 221 is energised. The annular step 235 is also configured so that while the electromagnetic coil 221 is energised, no compressive force is applied to the annular step between the floating core 237 and the distal spacer 227.

Referring to figure 10, the solenoid unit 43/143 is shown with the spindle 231 and its associated plungers in the withdrawn position, while the electromagnetic coil 221 is energised. As can be seen, the floating core 237 shown in figure 10 is attracted towards the distal end of the solenoid unit 43/143. When the electromotive force is removed from the electromagnetic coil 221, the floating core 237 will be pushed towards the proximal end of the solenoid unit 43/147 until it comes to rest on the radial step 219,

Incorporation of the further solenoid 241 into the solenoid unit has further advantages. As by necessity, the main solenoid including the electromagnetic coil 221 must be quite large, in order to overcome the shear forces which are applied to the plunger 47/147, incorporating the further solenoid unit 241 which acts as a latch, results in power savings due to the fact that the electromagnetic coil 221 is not required to be energised for the whole duration that the speed limiting device is in the second condition, whilst the predetermined maximum speed is maintained.

In order to release the plunger 47/147 into the first condition, or extended position, electromotive force is applied to the coil 247 of the further solenoid unit, actuating the further solenoid unit, resulting in its plunger 243 being withdrawn. The force exerted by the compression spring 239 then carries the spindle 231 and its plungers towards the proximal end of the solenoid unit 43/143, extending tbe plunger 47/147.

The sliding parts in the solenoid unit 43/143 should have bushes to minimise wear. These bushes are not shown but their positioning within the solenoid unit 43/143 should be apparent to a person skilled in the art.

The plunger 47/147, spindle 231 an plunger 233 should be formed of stainless steel or a similarly hard non ferromagnetic metal. The proximal end cap 213 and distal end cap 215 are ideally made of a non ferromagnetic metal such as aluminium, or a material such as a plastic. The outer casing 211, proximal spacer 225, distal spacer 227 and floating core should be made of a metal capable of concentrating a magnetic field, such as mild steel. The plunger 243 is also made of a metal capable of concentrating a magnetic field.

The fourth embodiment, shown in figures 11 to 15, is shown in figure 13 connected to a carburettor 311 having a choke 313 and a butterfly valve 315 mounted in the choke 313 on a spindle connector 317.

The embodiment comprises a throttle actuating means 321 which can be substituted for any of the throttle actuating means described in the preceding embodiments. The throttle actuating means 321 comprises a solenoid unit 143 as hereinbefore described, preferably the solenoid unit described with reference to figures 9 and 10, the solenoid unit 143 functioning as a mechanism. The throttle actuating means 321 is connected by a control cable 329 to a servo unit (not shown) . The control cable 329 is secured to the throttle actuating means 321 at a pop connector assembly 336.

The throttle actuating means 321 includes a first arcuate member 337 and a second arcuate member 339. The control cable 329 is connected to the second arcuate member 339 at the pop connector assembly 336 located thereon.

The first arcuate member 337 receives the proximal end cap 213 of the solenoid unit 143 in a mount 341, in such a manner that the plunger 147 may be received .through apertures (not shown) located in portions 343 forming separate parts of the first arcuate member 337 and the second arcuate member 339. The apertures in the portions 343 are coincident only when the first arcuate member 337 is in a relative rest position relative to the second arcuate member 339.

The first arcuate member 337 and the second arcuate member 339 are mounted to the spindle connector 317 of the carburettor 311, about a central axis 345 which the first arcuate member 337 and the second arcuate member 339 may rotate. The central axis is secured to a flange arrangement 347. The second arcuate member 339 is secured in relation to the flange arrangement by a resilient spring 348, which is provided to provide some resilience to the rotational connection between the central axis 345 and the second arcuate member 339.

The first arcuate member has a microswitch 351 mounted thereto having an actuator 353 for contacting a stepped portion 355 of the second arcuate member 339. In this manner, the relative rest position of the first arcuate member 337 in relation to the second arcuate member 339 can be determined by actuation of the microswitch 351. The central axis 345 has a key 357 which protrudes into a cutout 359 located in the second arcuate member 339, for limiting the rotation of the second arcuate member 339 about and relative to the central axis 345. A throttle cable 363 connects to the accelerator pedal of the motor vehicle and to the first arcuate member 337 by a pop connector 365. A return spring 369 is connected to the second arcuate member 339 for restraining movement of the second arcuate member 339 against the servo unit (not shown) . A further return spring 371 is provided for restraining the movement of the first arcuate member 337 against the accelerator pedal in the motor vehicle.

The throttle actuator of this embodiment operates in exactly the same manner as the throttle actuators described in the previous embodiments, particularly those described with reference to the second and third embodiments, except that the added feature of the resilient spring ensures that if excessive force is applied to the accelerator pedal, transmitted through the throttle cable 363 to the first arcuate member 337, the resilient spring 348 will stretch, taking up the excessive force, and reducing the shear forces across the plunger 147 of the solenoid unit 143, which would otherwise hinder the solenoid unit 143 from actuating. Referring specifically to figures 11 to 13 inclusive, the throttle actuator is shown with the carburettor in the idle condition, and with no force applied to either the control cable 329 or the throttle cable 363. In figures 11 to 13 inclusive, the first arcuate member 337 and second arcuate member 339 are in the relative rest position. Figure 14 shows the throttle actuating means 321 with the first arcuate member 337 and the second arcuate member 339 in the relative rest position, but with excessive force applied to the first arcuate member 337 via the throttle cable 363. As a result of the excessive force applied through the throttle cable 363, the resilient spring 348 has yielded to allow the entire throttle actuating means 321 to rotate about the central axis 345, the resilient spring 348 absorbing the excess force, reducing the shear force exerted at the apertures in the portions 343 of the first arcuate member 337 and the second arcuate member 339 on the actuator 147. It should be noted that pin 375 is attached to the flange arrangement 347.

Referring to figure 15, the throttle actuating means 321 is shown in the condition, where the servo unit is controlling the throttle setting via the control cable 329, and the accelerator pedal in the motor vehicle has been pressed to its maximum extent of travel causing the first arcuate member 337 to be displaced to its maximum rotational extent. This has no. effect on the throttle setting, as in the condition displayed in figure 15, the position of the throttle is controlled by the servo unit (not shown) acting on the second arcuate member 339.

The speed limiting device of this invention ensures that maximum acceleration can be obtained from a motor vehicle without exceeding the preselected speed, as selected on the selector switch 77/177.

A further embodiment is envisaged where the further selector switch 79/179 is not used, and the speed limiter is installed in heavy transport vehicles such as trucks, prime movers and busses, for the purpose of preventing excessive speeds in these vehicles on the open road.

Having ascertained the throttle actuating means 21/121 described in this embodiment, it is possible to build the speed limiting unit by making pertinent modifications to an existing cruise control unit. Whether a modified cruise control unit or a purpose built electronic processor 73/173 is used, it is envisaged that retro fitting this speed limiting device in existing vehicles will be a relatively straightforward exercise.

Furthermore, the feature of the solenoid causing disconnection of the throttle actuator from the operable control makes this unit particularly suitable for use in disabling a vehicle in the event of theft. Moreover, by the provision of a keypad or similar decoding input unit connected to an encoded switching circuit associated with the drive circuit of the solenoid, the circuits can \zz>e arranged so that when the ignition is switched on, the plunger is activated to withdraw from the aperture, until a code has been entered via the decoding input unit which correctly decodes the encoded switching circuit. In this manner, the vehicle will only be permitted to idle until the encoded switching circuit is correctly decoded, whereupon the system will return to its normal selected mode.

It should be appreciated that the scope of the present invention is not limited to the scope of the embodiment described herein. In particular, a remotely mounted solenoid, having a sliding cable connection connecting the solenoid unit to the apertures in the throttle actuating means which is mounted on the carburettor which will result in being able to reduce the size of the throttle actuating means, and is considered to fall within the scope of the invention. Similarly a remotely mounted throttle actuating means is considered to fall within the scope of the invention. Various other methods of separating the two members which move in relation to each other, in the throttle actuating means are envisaged, for example solenoids having a worm drive connecting the plunger to the electrical motor, air operated or hydraulically operated plungers, or indeed an electro-clutch arrangement are suitable in the practice of the invention. It should be noted, however, that where a plunger is used, both the shape of the plunger and the shape of the apertures in the components in the throttle actuating means which receives the plunger, should be tapered.

Claims

THE CLAIMS defining the invention are as follows:-

1. A throttle actuating means for interfacing an operable control and a throttle actuator, said throttle actuating means including a first member cooperating with a second member, a mechanism for cooperating with said first member and said second member, and sensing means associated with said members adapted to sense a relative position of said members corresponding to a relative rest position of said members, said first member being adapted for connection to said operable control and said second member being adapted for connection to said throttle actuator, said mechanism being selectable between a first condition and a second condition when said members are in said relative rest position, wherein in said first condition said mechanism locks said first member and said second member together, and in said second condition said mechanism unlocks said first member from said second member for relative independent movement in relation, to each other.

2. A throttle actuating means as claimed in claim 1 wherein said sensing means includes a switching means cooperating therewith.

3. A throttle actuating means as claimed in claim 2 wherein said switching means includes a proximity switch mechanism, hall effect sensor arrangement, or a light beam sensor arrangement.

4. A throttle actuating means as claimed in any one of the preceding claims 14 to 16 wherein said first member and said second member are mounted for rotational movement coaxial with said throttle actuator.

5. A throttle actuating means as claimed in any one of claims 1 to 3 wherein said first member and said second member are mounted for linear sliding movement in relation to each other when said mechanism is in said second condition.

6. A throttle actuating means as claimed in any one of the preceding claims 1 to 6 wherein said mechanism comprises an electrically operated solenoid arrangement.

7. A throttle actuating means as claimed in claim 6 wherein said electrically operated solenoid is mounted remotely from said first member and said second member.

8. A throttle actuating means as claimed in claim 6 or 7 wherein said electrically operated solenoid arrangement comprises a solenoid having an electromagnetic coil and a plunger moveable along a central axis between an extended position corresponding to said first condition and a retracted position corresponding to said second condition, and biased toward said extended position, and having a magnet core slidably mounted on said plunger moveable between a distal point located toward said extended position and a stop located on said plunger at a proximal point located away from said extended position and located relatively toward said electromagnetic coil.

9. A throttle actuating means as claimed in claim 8 wherein said magnet core is biased on said plunger toward said distal point.

10. A throttle actuating means as claimed in any one of claims 6 to 9 wherein said electrically operated solenoid arrangement includes a second solenoid associated with said solenoid, adapted to selectively hold said plunger in said retracted position, said second solenoid having a second plunger mounted normally to said plunger and biased toward a second extended position in which it is adapted to interfere with said plunger in. said retracted position to retain said plunger thereat, and actuable to a second retracted position to release said plunger. ,

11. A throttle actuating means as claimed in any one of the preceding claims including means for limiting shear forces applied at said mechanism by said first and second members.

12. A throttle actuating means as claimed in claim 10 wherein said means for limiting comprises a resilient connection between said second member and said throttle actuator.

13. A speed management device for limiting the speed of a motor to a predetermined maximum speed comprising an apparatus for interfacing a throttle actuator with an operable control, said apparatus comprising a throttle actuating means as claimed in any one of claims 1 to 12 and a control means, said mechanism being provided for selectively connecting and disconnecting said throttle actuator from said operable control, and said sensing means being adapted to sense a relative position at which said mechanism may operate to connect said throttle actuator to said operable control, said control means including a first control means for selectively operating said mechanism, a second control means for selectively controlling said throttle actuator, and detection means for detecting instantaneous motor speed; wherein said control means is adapted to allow said operable control to actuate said throttle actuator until said control means detects that said predetermined maximum speed has been reached or exceeded, whereupon said control means is adapted to actuate said mechanism to disconnect said operable control from said throttle actuator, and is adapted to control said throttle actuator to substantially maintain said predetermined maximum speed.

14. A speed management device as claimed in claim 13 wherein said control means is adapted to actuate said mechanism to disconnect said operable control from said throttle actuator at a speed exceeding said predetermined speed and thereafter said control means is adapted to control said throttle actuator to substantially maintain said predetermined maximum speed.

15. A speed management device as claimed in claim 13 or claim 14 wherein said control means is adapted to actuate said mechanism to reconnect said operable control to said throttle actuator when said sensing means senses said relative position whilst said predetermined maximum speed is substantially maintained.

16. A speed management device as claimed in claim 145 wherein said control means is adapted to release control of said throttle actuator when said sensing means senses said relative position whilst said predetermined maximum speed is substantially maintained, restoring control to the operator thereof.

17. A speed management device as claimed in any one of claims 13 to 15 wherein said control means also includes brake sense means for sensing overriding control to slow said motor, and is adapted to maintain said predetermined maximum speed when said sensing means senses said relative position; wherein while said predetermined maximum speed is substantially maintained and upon said brake sense means sensing said overriding control, said control means is adapted to actuate release control of said throttle actuator, to restore control to the operator thereof.

18. A speed management device as claimed in any one of claims 13 to 17 wherein said first condition is adapted to be selected at a motor speed less than said predetermined maximum speed, and said second cond tion is adapted to be selected at a motor speed substantially equal to or exceeding said predetermined maximum speed

19. A speed management device substantially as herein described, with reference to the description of any one of the embodiments.

20. A throttle actuating means substantially as herein described, with reference to the description of any one of the embodiments,