WO1982002859A1 - Device for retaining a power control-member of a vehicle engine in a selected position - Google Patents

Abstract

Device (59) for retaining the power control member of the engine of a vehicle in a selected position, this device comprising a housing (63), a first clutch part (60) journalled in a bearing member mounted movably on the housing and connected to the power control member, a second also movable clutch part designed to be placed in a desired position by the control member and housed in the housing and designed to be coupled to the first clutch part as well as a release member designed to be actuated by the slowing down of the vehicle to decouple the clutch parts, these parts comprising magnetic members.

Description

Device for retaining a power control-member of a vehicle engine in a selected position.

The invention relates to a device for retaining the power control member of a vehicle engine in a selected position, said device comprising a housing, a first clutch part joumalled in bearing means movably mounted in said housing and connected with the power control-member, a likewise movable second clutch part adapted to be set in a desired position by control-means and arranged in said housing and adapted to be coupled with the first clutch part and comprising release means actuable by decelerating the vehicle for disconnecting the clutch parts. When the vehicle engine is a petrol engine, the power control-member is the gas valve and when the vehicle engine is a Diesel engine, the power control-member may be the control of the injection pump. Such a device is known from Dutch patent application 75.03656. In this known device the second clutch part comprises a pivotally mounted lever provided with a lug adapted to grip behind a pawl of the first clutch part. The lever is furthermore provided with an extension protruding in the path of movement of a mass formed by a steel ball. The lever is constructed so that its centre of gravity lies outside the pivotal point. As a result of gravity it is thus constantly held in the position in which the lug can grip behind the pawl. The disadvantage of this known device is that due to soiling of the lever hinge in the course of time the lever will no longer turn about the pivotal point without difficulty so that the operation of the device may be disturbed. Moreover, after a lapse of time wear of the pawl and the lug will occur because at each disconnection of the two clutchparts the lug slides along the pawl. This sliding movement occurs whilst the power control-member continuously transfers a considerable force. This disadvantageous load results in the above mentioned wear. Due to said wear and due to the less satisfactory movability of the lever, the operation of the known device becomes unsafe in the course of time. Since such devices are used in vehicles intended for road transport. such unsafe operation may give rise to hazardous traffic situations. If, for example, due to a defective turn the lever does not establish a connection between the two clutch parts, the attention of the vehicle driver is distracted. Due to wear of the pawl and the lug, the connection may abruptly disengage, resulting in unexpected deceleration of the vehicle, which is dangerous for the oncoming traffic.

The invention has for its object to provide a device of the kind set forth in the preamble, which will safely operate even after a long time.

According to the invention this is achieved by providing the clutch parts with magnetic means. This obviates the necessity of using dirt-sensitive fulcra and lugs and pawls subjected to wear so that the device will always operate reliably. A simple and hence safely operating construction is obtained, when in accordance with the invention the release means comprise a mass freely movable along a path on a guide path provided in the housing and the bearing means journal the first clutch part so as to be displaceable sub- stantially parallel to the guide path in a direction of displacement and the first clutch part comprises a stop protruding in the path of movement. When the vehicle decelerates the mass develops a given speed before it comes into contact with the stop. The resulting impact is sufficient to produce the disconnection.

In an advantageous embodiment of the invention the bearing means hold the first clutch part so as to be also rotatable about an axis extending in the direction of displacement,, the stop has a face inclined to the path of move- ment and producing upon the impact of the mass a rotation of the first clutch part about the axis and the clutch parts can be coupled along contact surfaces having forms deviating from surfaces of revolution. Owing to the rotation the contact between the clutch part is drastically diminished so that the "adhesive force" is strongly reduced and, the clutch parts readily disengage. By this preferred embodiment it is consequently ensured that whereas under normal conditions the clutch parts are firmly coupled with one another, disconnection occurs already at a slight deceleration. In a preferred embodiment of the invention the magnetic means are formed by at least one electro-magnet. The electromagnet can be simply switched on and off so that the entire device can be put into and out of operation in a simple manner.

When the magnetic means comprise an electro-magnet, the release means may advantageously comprise in accordance with the invention a mercury switch included in the current supply circuit of the electro-magnet and consisting of a housing having at a rear end inwardly protruding electrodes to be interconnected electrically by a mercury droplet, said housing being connected by mounting means with the vehicle in a position inclined upwards from the rear end in the direction of travel. Upon deceleration of the vehicle the mercury droplet will move forwards in the housing of the switch and thus disrupt the connection between the electrodes. As a result the electro-magnet is switched off and the clutch parts are. disengaged. The housing comprising the clutch parts may then be mounted at any place and in any position in the vehicle. Mounting of the device is thus considerably simplified. It is only necessary to mount the mercury switch in a given position.

When in accordance with the invention the mounting means connect the housing of the mercury switch with the vehicle so as to be rotatable about a substantially horizontal axis transverse of the direction of travel, the angle of inclination of the housing can be adjusted and hence the minimum deceleration at which discoupling occurs. According as the housing is disposed in a more inclined position, the mercury switch will interrupt only at a greater deceleration.

Further features and advantages of the invention will become apparent from the following description of embodiments shown in the drawings.

Fig. 1 is a partly schematic longitudinal sectional view of a preferred embodiment of the device in accordance with the invention,

Fig. 2 is a perspective view, partly broken away, of the device of Fig. 1,

Fig. 3 is a perspective view of a detail of the clutch parts of the device shown in the preceding Figures,

Figs. 4, 5 and 6 show schematically alternative embodiments of the clutch parts,

Fig. 7 schematically shows a different embodiment of the device in accordance with the invention.

Fig. 8 schematically shows a preferred embodiment of the device comprising an electro-magnet,

Fig. 9 shows a different embodiment of the release means for the device of Fig. 8, Fig. 10 shows a further embodiment of the release means.

The device 1 comprises a housing 2 accomodating a first clutch part 4 and a second clutch part 6. The second clutch part 6 can be fixed in an axial position in the housing with the aid of control-means 5. The first clutch part is connected through a cable 13 with the gas pedal 8, which actuates the power control-member of the engine of a vehicle in which the device 1 is mounted. When the engine is a petrol engine, the power control-member is a gas valve and when the vehicle engine is a Diesel engine, the power control-member can control the injection pump. The gas pedal 8 is pivoted to the vehicle 11 by means of a hinge 9 and is coupled through a control-rod 10 with the power control-member. The gas pedal 8 is loaded by a spring 12 urging the gas pedal into a position indicated by broken lines corresponding to the minimum power of the engine.

When the clutch parts 4, 6 are coupled, the device 1 prevents, by means of the cable 13 engaging the gas pedal 8, the spring 12 from retracting the gas pedal 8 beyond a position set by the control-means 5. When in this situation the vehicle is braked, the release membexs 7 included in the device 1 ensure that the clutch parts are disengaged from one another in a manner to be described more fully hereinafter. As a result the gas pedal can be withdrawn by the spring 12 into the position indicated by broken lines. The second clutch part 6 maintains its set position so that, when subsequently the gas pedal 8 is again depressed, the first clutch part 4 can again be coupled in the same position with the second clutch part 6.

The first clutch part 6 comprises a slide 17 displaceable in a support 14 connected with the housing 2. The support 14 has stops 15, which co-operate with a lug 16 rigidly connected with the slide 17, for limiting the stroke of the slide 17. At the right-hand end as viewed in Fig. 1 the slide 17 has a cable clamp 18, in which a cable 23 can be clamped by. means of a screw 19. The cable 23 is connected with the knob 24 of the control-means 5. The knob 24 is slidable in known manner in a guide 27. In the control-knob 24 is recessed a slot 25 into which extend pins 26 rigidly connected with the guide 27. By turning the control-knob 24 the wall of the knob 24 can be brought into engagement with said pins 26. The knob 24 is made of a material such that it is not permanently deformed by the engagement of the pins 26 and resumes its initial shape when released by turning back the knob 24. Consequently the control-knob 24 can be fixed in any selected position by displacing it in an axial direction in a rotational position in which the pins 26 protrude in the slot 25 and by subsequently turning the knob 24.

The cable 13 is sufficiently rigid to move the clutch part 4 to 6, when the gas pedal 8 is used, the clutch part 4 being attracted by 6. When the coupling is established and when more gas has to be supplied for a short time (in overtaking) the cable 13 is sufficiently flexible to bend, after which the cable is again stretched by the force of the spring 12.

The control means 5 may be arranged at a different place rather than directly on the housing 2. This place may be on the instrument panel of the vehicle. The cable 23 may then, if desired, be guided through an outer cable. At the left-hand end the slide 17 has a magnet 20 having two outwardly projecting pole shoes 21, 22. These pole shoes 21, 22 co-operate with a chuck plate 34 of the first clutch part 4. The chuck plate 34 is rigidly mounted on a stop 30, which is freely rotatable on a shaft 29. The stop 30 is enclosed between the rings 31 and fixed with the aid of a screw 33.

The housing 2 also includes the release means 7 comprising a guide path 37 and a steel ball 36 movable therein. The housing 2 is mounted in the vehicle at a small angle A to the horizontal so that in the rest position the ball 36 is located on the right-hand side of the guide path 37. The normal direction of travel is to the left as viewed in fig. 1. When the vehicle decelerates by the driver applying the brakes, the ball 36 moves owing to its inertia in the housing 2 along the guide path 37 to the left and strikes the stop 30. As a result the pole shoes 21, 22 and the chuck plate 34 are disengaged .from one another. The first clutch part 4 can then move to the left under the action of the spring 12 When afterwards the gas pedal 8 is again depressed, the first clutch part 4 again moves towards the second clutch part 6. When the gas pedal 8 is depressed to an extent such that the chuck plate 34 can come into contact with the pole shoes 21, 22 of the magnet 20, the clutch parts 4, 6 are recoupled.

In order to ensure that even at a slight deceleration an hence at a small shift of the ball 36 discoupling occurs, the stop 30 has, in accordance with a preferred aspect of the invention, a surface 35 inclined to the path of movement of the ball 36. When the ball 36 moves in the direction of the arrow 38 towards the stop 30 and comes into contact with the sloping face 35, a radial force in addition to the axial force is exerted on .the stop 30 so that the latter turns in the direction of the arrow 39 (fig. 2) . Since the chuck plate 34 is curved and is arranged on the stop 30 in a manner such that in the normal hanging position of the stop 30 said chuck plate 34 is in contact along lines with the pole shoes 21, 22 of the magnet 20, the contact face between the chuck plate 34 and the pole shoes 21, 22 is directly reduced to two points (see Fig. 3) by said turn in the direction of the arrow 39. The retention force of the magnet on the chuck plat 34 is thus drastically reduced so that the first clutch part 4 can be drawn away from the second clutch part 6 by the action of the spring 12. This effect is each time obtained when the contact faces of the clutch parts do not have the shape of a plane of revolution about the axis, about which the stop can turn. Figs. 4, 5 and 6 show a few other examples of contact faces fulfilling said conditions- At each turn of the clutch parts 4, 6 relative to one another the contact surface is thus very greatly reduced so that the magnetic retention force is also very drastically reduced.

It will be obvious that for a satisfactory. operation of the device it is irrelevant whether the magnet is incorporated in the first or in the second clutch part.

Fig. 2 shows furthermore a guide 40, which ensures that the chuck plate 34 comes in the correct position into contact with the pole shoes 21, 22 of the magnet 20. Since the centre of gravity of the stop 30 has shifted to the right owing to the sloping face 35, the stop 30 is held in contact by gravity with the guide 40. The design of the contact faces may, however, be such that the guide 40 is not required and that by the free rotatability of the stop 30 about the axis 29 the chuck plate 34 automatically finds the correct positon.

Although the path of movement of the ball 36 is shown to extend substantially in the same direction as the displacement of the first clutch part 4, said path of movement may be transverse of said direction. The ball then mainly brings about the turn of the stop 30 in the direction of the arrow 39, whilst in addition an inclined surface 35 may be provided for generating an axial force component on the first clutch part 4. The preferred axpect of the invention for strongly reducing the contact surface between the clutch parts in behalf of discoupling is also applied to the device shown in Fig. 7. Only the essential parts are shown and parts like the setting means and the connection with the power control-member are omitted.

The first clutch part 46 of the device 45 is connected with the power control-member, whereas the second clutch part 47 is connected with setting means. The second clutch part carries a fork 48, in which a contact element 49 is mounted so as to be rotatable about a tilting shaft 50. For coupling the clutch parts 46, 47 the contact element 49 can come into contact with the magnet 51 of the clutch part 46.

The device 45 also comprises release means 52 having a guide path 53 and a steel ball 54 movable along the same. At a deceleration of the vehicle the ball 54 strikes the lower end 56 of the contact element 49, which thus tilts about the tilting shaft 50. Thus the contact surface between the magnet 51 and the contact element 49 is reduced to the lower point 55 of the triangular magnet 51. The magnet 51 is then drawn away from the contact element 49 by the tractive force exerted on the first clutch part 46. By an appropriate design of the fork 48 or by providing a stop thereon the tilting angle of the contact element 49 can be limited. Apart from the triangular shape of the magnet 51 as shown, other shapes are possible. For example, a magnet having two vertically extending pole shoe's may be used.

In the above mentioned embodiments the desired sensitivity to deceleration can be obtained by a suitable choice of the size of the movable mass, shown in the Figures in the form of a ball, and of the distance of the contact point between the mass and the stop or the contact element from the contact surface.

Fig. 8 shows a preferred embodiment of the device in accordance with the. invention. Since the principle of the operation corresponds with that of the device described above the device 59 will be described only as far as it differs from the preceding embodiments.

The first clutch part 60 coupled with the power control-member of the combustion engine comprises a pin 65. The pin 65 can be magnetically engaged by an electro-magnet 62 forming part of the second clutch part 61 connected with the control means 5. The electro-magnet 62 is of the type having a bore 64 receiving the pin 65. The first clutch part 60 and the second clutch part 61 are arranged in known manner in the housing 63.

The electro-magnet 62 is included in a current supply circuit 66 schematically shown in Fig. 8. The current supply circuit 66 is connected by terminals 67 to a current source. This current source will particularly be the battery of the vehicle. The current supply circuit 66 includes a master switch 68 by means of which the device can be switched on and off. The current supply circuit furthermore includes an on-switch 69 which establishes a through-connection depressed. When the switch 69 is released, the connection is interrupted. When the on-switch 69- is actuated, the coil 71 of relay 70 is energized so that the contacts 72 are closed. By means of the circuit shown the on-switch 69 is bridged by the closure of the contacts 72, so that after the release of the on-switch 69 the relay 70 remains operative. By the closure of the contacts 72 the electro-magnet 62 is also switched on. In series with the master switch 68 the current supply circuit 66 includes a mercury switch 73. The mercury switch comprises a housing 74, at the rear end of which are arranged two electrodes 76. These electrodes 76 can be electrically interconnected by a mercury droplet 75, which is also located in the housing 74. The normal direction of travel of the vehicle is to the left as viewed in Fig. 8. The housing 74 of the mercury switch 73 is mounted in the vehicle in the position shown, in which the rear end of the housing 74 holding the electrodes 76 is at a lower lever than the opposite front end. Consequently, the mercury droplet 75 will interconnect the electrodes 76. When the vehicle decelerates, the mercury drop 75 is exposed to a relative force directed to the left with respect to the housing 74. When the deceleration is sufficiently great, the mercury drop 75 will move upwards to the left in the housing 74. Thus the connection between the electrodes 76 is interrupted and the current supply to the relay 70 and the electro-magnet 62 stops. The clutch parts 60 and 61 are thus discoupled. At the termination of the deceleration the mercury drop 75 moves back into the position shown, in which the electrodes 76 are interconnected. The electromagnet,, however, remains out of circuit because the contacts 72 of the relay 70 are opened. By actuating the on-switch 69 the device is again switched on, the power control-member of the combustion engine being again retained in the position set earlier by means of the control-means 5. The current supply circuit may, of course, also be designed so that the mercury switch 73 controls the current supply to the electro-magnet 62 directly or, if desired, through a relay. Then at the termination of the deceleration the electro-magnet 62 is directly switched on again. This has MPI the advantage that it is not necessary to carry out a separat operation i.e. the actuation of the on-switch 69. The driver has, however, to take care that after deceleration the master switch 68 is actuated, since otherwise the gas pedal might "stick", resulting in potential damage of the engine, when reswitching is performed after the deceleration and the disconnection. As a matter of course, this inconvenience only occurs in a vehicle having a manually operated gear box and does not apply to an automatic gear box. Preferably, the mercury switch 73 is connected by mounting means 77 with the vehicle, said means being rotatable in the direction of the arrow 78. Thus the angle of inclination of the housing 74 of the mercury switch can be adjusted and hence he minimum deceleration at which the current supply circuit 66 is interrupted. The greater the angle of the housing 74 to the horizontal, the greater is the deceleration at which interruption occurs.

In the event the mercury switch directly interrupts the current supply to the electro-magnet 62, it is preferred to use the switch 80 of Fig. 9. In this case the mercury switch 81 having electrodes 82, which are electrically interconnected by a mercury drop 83 in the position shown, is fastened to a manually operated lever 84. The manually operable lever 84 is mounted by means of a hinge 87 on a mounting plate 85. The mounting plate 85 can be mounted in the instrument panel of the vehicle. When the hand lever 84 is moved upwards in the direction of the arrow 89, the mercur switch 81 is tilted downwards so that the mercury drop 83 moves towards the other end of the housing of the mercury switch 81. The electrodes 82 are thus electrically disconnected. In this way the mercury switch 81 may also serve as a master switch. In the position shown for the manually operable lever 84 the device is in its operational position and in the upwardly turned position of the lever 84 the device is switched off. In the embodiment of the switch 80 shown the manually operable lever 84 is provided with a lug 86, which can come into contact with a stop screw 88. The stop screw 88 determines the maximum inclination of the mercury switch 81. By the screw 88 the deceleration can be set at which the switch 81 becomes operative in the same manner as described above for Fig. 8. Instead of using a set screw 88 the stop may be formed by the lower end of the opening 90 in the mounting plate 85 co-operating with the manually operable lever 84 in order to determine the maximum angle of inclination of the mercury switch 81.

Fig. 10 shows a different embodiment of the deceleration switch. The mass of the switch 91 is formed by a ball 92.

The ball 92 is movable in a V-shaped gutter 96, which is upwardly inclined in the direction of travel of the vehicle In the situation illustrated in Fig. 10 the ball 92 is exposed to an acceleration indicated by the arrow 95 so that the ball 92 has rolled upwards to the guide path 96. The electrodes 93 of the deceleration switch 91 have resilient tags 94, which in the unstressed state, are free of contact tips 97 in the V-shaped gutter, When the ball 92 rolls back, its weight urges the resilient contacts 94 against the contract strip 97 so that again an electric connection is established between the electrodes 93.

Claims

CLAIM

1. A device for retaining the power control-member of a vehicle engine in a selected position, said device comprising a housing, a first clutch part joumalled in bearing means movably mounted on said housing and connected with the power control-member, a likewise movable second clutch part adapted to be set in a desired position by control-means and accomodated in said housing and adapted to be coupled with said first clutch part and release means adapted to be actuated by deceleration of the vehicle for discoupling the clutch parts characterized in that the clutch parts comprise magnetic means.

2. A device as claimed in Claim 1 characterized in that the release means comprise a mass freely movable along a path of movement on a guide track arranged in the housing, in that the bearing means hold the first clutch part so as to be slidable substantially parallel to the guide track in a direction of displacement and in that the first clutch part comprises a stop protruding in the path of movement.

3. A device as claimed in Claim 2 characterized in that the bearing means hold the first clutch part so as to be also rotatable about an axis extending in the direction of displacement, in that the stop has a surface inclined to the path of movement and causing, when engaged by the mass, rotation of the first clutch part about the axis and in that the clutch parts can be coupled through contact surfaces having shaped deviating from planes of revolution.

4. A device as claimed in Claim 3 characterized in that one of the two clutch parts has two relatively spaced, parallel pole shoes of a magnet and the other clutch part has a unidimensionally curved surface co-operating with said magnet.

5. A device as claimed in Claim 1 characterized in that the release means comprise a mass freely movable along a path of movement on a guide track arranged in the housing, in that the bearing means hold the first clutch part so as to be displaceable substantially parallel to the guide track in the direction of displacement and in that one of the two clutch parts comprises a contact element provided with a stop protruding in the path of movement and being pivotable about an axis being at an angle to the direction of displacement and crossing the path of movement.

6. A device as claimed in anyone of the preceding Claims characterized in that the magnetic means are formed by at least one electro-magnet.

7. A device as claimed in Claim 6 characterized in that the release means comprise a deceleration switch formed by a movable mass and by electrodes electrically disconnectable by said mass and included in a current supply circuit of the electro-magnet.

8. A device as claimed in Claim 7 characterized in that the switch is formed by a mercury switch comprising a housing having at a rear end inwardly protruding electrodes electrically disconnectable by a mercury drop, said housing being connected by mounting means with the vehicle in a position upwardly inclined from the rear end in the direction of travel.

9. A device as claimed in Claim 7 characterized in that the mounting means connect the housing with the vehicle so as to be rotatable about a substantially horizontal axis transverse of the direction of travel.

10. A device as claimed in Claim 9 characterized in that the mercury switch is connected with a manually operable, pivotable lever.