GB2177767A - Motor vehicle braking system - Google Patents

Abstract

The system provides automatic braking when the vehicle (as shown a trailer), moving in reverse contacts an obstruction; a member 56 rotates in one direction in the forward direction of movement of the vehicle 10 and in the opposite direction in the reverse direction of movement of the vehicle 10 and upon rotation of the member 56 in said opposite direction being sensed the brake system 71 is brought into readiness for operation by detector means sensing contact of e.g, a bumper tube 22 with an obstruction. As shown member 56 is a disc fixed to a hub cap 34 and carrying magnets 62 which registers with a ring 46 of magnet, on a disc 38. Forwards rotation of disc 56 rotates disc 38 in one direction but in the opposite direction movement of disc 38 opens a valve 52-contact of tube 22 with an obstruction operates valve 74 to operate the brakes. in the embodiment of Figs. 11-13 a drive shaft (150) carries a circumferential band of magnets cooperable with an arcuate head (154) carrying magnets. The specification envisages rotation sensing by fluid, hydraulic, mechanical electrical means or a combination - detection may utilize a bar, rail, sensing strip, sonar or infra red. <IMAGE>

Description

SPECIFICATION Motor vehicle braking system This invention relates to a motor vehicle braking system providing automatic braking when the vehicle, moving in reverse, detects an obstruction.

It is already known, particularly in connection with goods-carrying vehicles, to provide at the rear of the vehicle (which may for example be a wagon or the trailer of a tractor/trailer combination) a detector which, when the vehicle reverses, detects an obstruction and serves to generate a signal which can be used to initiate application of the vehicle's brakes so bringing the vehicle to a standstill and minimising the risk of damage or injury to any obstruction or person behind the vehicle.

There are several types available, and at least one such known system is interrelated to a driver-controlled reverse selector on the vehicle in such a manner that the system is armed or made ready for brake application to be effected upon receiving a signal from the detector only when the vehicle's driver has selected reverse gear. Thus, with this system a signal generated by the detector causes brake application only when the vehicle's driver has deliberately operated the selector for the vehicle to be driven backwards.

There are other methods which necessitate the engaging of an electrical switch, or the operating of a camera and associated equipment, and rely on the driver to control or activate. None of these will operate, therefore, if for instance the vehicle should commence running backwards, e.g. down a hill when out of gear, or as a result of being impacted at the front. Thus, the prior proposed systems do not safeguard against the risk of accident in the event of unintentional reverse movement of the vehicle, which can arise in a substantial number of varied circumstances of which possibly the most important one is the risk arising from inattentive parking upon an inclined surface.

An object of the present invention is to provide a method of automatically actuating the braking system of a vehicle which safeguards against any reverse movement, whether intentional or unintentional, and in which the need for the operation of switched, or a reverse selector of the vehicle to have been shifted into the reverse condition, is obviated.

A second object of the present invention is to provide a motor vehicle braking system and a third object is to provide a unit connectable to a braking system of a vehicle for automatically actuating the braking system.

With the first object in view the present invention provides a method of automatically actuating the braking system of a vehicle comprising the steps of detecting the vehicle contacting an obstruction when the vehicle is moving backwards and thereby generating a signal, sensing the rotational direction of a member which rotates in one direction in the forward direction of movement of the vehicle and in the opposite direction in the reverse direction of movement of the vehicle and arming the system, upon sensing rotation of the member in said opposite direction, for the detector signal to cause brake application.

With the second object in view, the present invention provides a motor vehicle braking system comprising detector means, positioned on the vehicle, constructed and arranged to detect the vehicle contacting an obstruction when the vehicle is moving backwards and generating a signal on said contact, sensor means effective to sense the rotational direction of a member which rotates in one direction in the forward direction of movement of the vehicle and in the opposite direction in the reverse direction of movement of the vehicle, said sensor means serving, upon sensing rotation of the member in said opposite direction, to make ready or arm the system enabling the detector signal to cause brake application and means actuable by the detector signal to cause brake application.

With the third object in view the present invention provides a unit connectable to a braking system of a vehicle for automatically actuating the braking system comprising detector means actuable on rearward movement of the vehicle to generate a signal, sensor means constructed and arranged to sense the rearward movement of the vehicle, pneumatic means connected with the sensor means to arm the braking system enabling the detector signal to cause brake application on said rearward movement and pneumatic means actuable by the detector signal to cause said brake application.

The sensor means may comprise any suitable means which senses rotation of any practical component of the vehicle which rotates in the one direction on forward movement of the vehicle and in the opposite direction upon backward movement of the vehicle. For instance, the vehicle component may be an axle or a drive shaft thereof, and the sensor means may be fluid sensor means, hydraulic, mechanical or electrical, or a combination thereof.

The detector means are for example in the form of a bar or rail, a sensing strip, sonar or infra red or other means.

The method of automatically actuating the braking system of a vehicle preferably includes the step of releasing brake application to the armed mode allowing for movement of the vehicle. Additionally the method further includes the step of disarming the system when the vehicle moves forward.

The motor vehicle braking system advantageously includes means to release brake application to the armed mode for movement of the vehicle. Preferably means to disarm the system when the vehicle moves forward are further included.

Advantageously the means to cause brake application is pneumatic and further the sensor means preferably comprise a pair of spaced, opposed interacting magnet means, one mounted on an element of the vehicle and movable therewith and the other mounted on a fixed element of the vehicle.

Preferably in the unit connected to a braking system of a vehicle the sensor means is constructed and arranged to sense the rotational direction of a member which rotates in one direction on the forward direction of movement of the vehicle and in the opposite direction on the reverse direction of movement of the vehicle. Advantageously the detector means of the unit is pneumatic.

The invention wiil be described further by way of example with reference to a preferred embodiment of the invention illustrated in the accompanying drawings in which: Fig. 1 is a perspective view of the rear portion of the trailer of a tractor-trailer combination; Fig. 2 is a transverse cross-sectional view of the rear bumper of the trailer taken along line 2-2 of Fig. 1; Fig. 3 is a cross-sectional view of a first embodiment associated with the wheel hub assembly of the trailer of Fig. 1; Fig. 4 is an exploded perspective view of the rotation detector of the wheel hub assembly of Fig. 3; Fig. 5 is a view of the magnetic activator disc of the rotation detector of Fig. 4 taken along line 5-5 of Fig. 3 and showing its position in relation to the valve pin when the trailer is moving forwardly; Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 5;; Fig. 7 is a view similar to Fig. 5 showing the position of the disc in relation to the valve pin when the trailer is moving in reverse; Fig. 8 is a cross-sectional view taken along line 8-8 of Fig. 7; Fig. 9 is a schematic flow diagram of the air brake system of the device; Fig. 10 is a flow diagram similar to Fig. 9 showing the brake system in operation; Fig. 11 is a cross-sectional view of a second embodiment of the invention associated with the drive shaft of a vehicle; Fig. 12 is a view taken along line 12-12 of Fig. 10; and Fig. 13 is a view taken along line 13-13 of Fig. 11.

The embodiment shown in the drawings consists of a trailer 10 of a tractor-trailer combination, with a body frame 12 and including a set of rear wheels 14 comprising a pair of wheels 16 journally mounted for free rotation on a fixed axle 18. A fixed bumper frame 20 depends from body frame 12 and carries a rearwardly projecting pneumatic bumper tube 22 of flexible material. As seen in Fig. 2, a second pneumatic tube 24 is disposed within bumper tube 22 and extends substantially the length of the bumper tube.

The hub assembly of one wheel 16 is shown in Fig. 3 and comprises a wheel hub 26 journally mounted by bearings 28 on a fixed axle 30 having an axle bore 32 closed at one end by a plug 32 which is fixed by set screws 33 to the axle and which faces a hub cap 34 mounted on boss 36 of wheel hub 26. As seen more particularly in Fig. 4, a first magnet disc 38 is axially mounted for rotation on plug 32 by a pivot bolt 40 and spaced from the plug by a bushing 42 on the disc.

The outer face 44 of disc 38 carries a ring 46 of fixed, spaced magnets. A stop pin 48 projects from plug 32 through a first aperture 50 in disc 38 and a spring air valve 52 projects from the plug through a second aperture 54 in disc 38 radially opposite to aperture 50 with respect to aperture 50. A second magnet disc 56 faces first magnet disc 38, being fixed to hub cap 34 on blocks 58 by bolts 60. Disc 56 carries a ring 62 of fixed, spaced magnets which registers with ring 46 on disc 38.

The air flow system associated with trailer 10, as shown in Fig. 9 of the drawings, consists of an air brake supply line 70 passing to brake system 71 of the trailer through a normally open port 72 of a first shuttle valve 74 and an auxilliary air line 76 normally closed by shuttle valve 74. Auxilliary air supply line 76 is connected by a line 78 to a pressure reducing valve 80 and from valve 80 through a line 81 to normally closed spring air valve 52. Line 81 is connected by a line 82 to control port 83 of a first normally closed pass control valve 84. Auxilliary air supply line 76 is connected through line 78 by a line 120 to pass control valve 84, thence by a line 86 to a second normally open pass control valve 88, and thence by a line 90 to connect with a line 92 impinging on one end 94 of a second shuttle valve 96 which bears at its other end on a compression spring 98. Line 92 connects also through a normally closed third pass control valve 100 and a line 102 to impinge on one end 104 of first shuttle valve 74. Air supply line 78 connects, by a line 106 through a normally open port 108 of second shuttle valve 96, with a line 110 which impinges on the other end 112 of first shuttle valve 74. Bumper tube 24 is connected by an air line 114 to control port 116 of pass control valve 100 and to a normally open port 118 of shuttle valve 96 to air. Brake supply line 70 is connected by a line 124 to control port 126 of pass control valve 88.

In the operation of the embodiment of Fig.

3 to 8 the operator normally controls the brake system of trailer 10 through brake line 70. When trailer 10 is moving forward magnetic disc 56 rotates magnetic disc 38 in the direction of arrow 130 as seen in Fig. 5 and pin 48 prevents valve 52 from being opened, as seen in Fig. 6. However, movement of trailer 10 in reverse, i.e. backwards, causes disc 56 to rotate disc 38 in the opposite direction as indicated by arrow 132 in Fig. 7 and this movement of disc 38 opens valve 52 as seen in Fig. 8.

The opening of valve 52 vents air from line 81, 82 which opens port 83 of valve 84 and allows pressurized air from line 120 to pass through valve 84, line 86, valve 88, line 90 and line 92 to throw shuttle valve 96, against the action of spring 98, in the direction of arrow 134 as seen in Fig. 10, thus sealing the venting of line 114 and relieving the pressure on end 112 of shuttle valve 74. Also the venting of bumper tube 24 is cut off. This brings the brake system into readiness for automatic operation by the contact of bumper tube 22 with an obstruction.

When bumper tube 22 comes into contact with any obstruction an air pulse is sent from tube 24 along line 114 to valve 100 which opens port 116 and allows pressurized air from line 92 to pass through line 102 and against end 104 of shuttle valve 74, throwing valve 74 in the direction of arrow 136 as seen in Fig. 10, thus closing line 70 and opening line 76 through part 138 to brake system 71. This automatically operates brake system 71 to stop the reverse movement of trailer 10 immediately.

In order to release the brake system from the automatically actuated mode the operator of the vehicle presses the foot brake which actuates valve 88 through lines 70 and 124 to port 126. This closes valve 88, cutting off the air supply to lines 90 and 92 and releasing the pressure on end 94 of shuttle valve 96. Shuttle valve 96 is thus allowed to be thrown back by spring 98 to its normal position and allows air from line 106 to pass through port 108 and line 110 to end 112 of shuttle valve 74 which throws that valve back to its normal position.

When the operator releases the foot brake, port 126 is closed which returns the system to its armed mode. On the resumption of forward movement of trailer 10, air valve 52 returns-to its normal closed position as seen in Fig. 5 and 6. This closes port 83 of valve 84, thus returning the system to its original (normal) mode of operation.

In the embodiment shown in Figs. 11 to 13 of the drawings the invention is activated through drive shaft 1 50 of a vehicle which carries a circumferential band 1 52 of magnets.

An arcuate head 154 floats over band 152 and comprises a curved plate 156 carrying a row 158 of magnets on its concave side concentric with band 1 52. Head 154 is carried by a pair of support arms 160 fixed to a block 162 on the chassis of the vehicle. The free end portion 164 of each arm 160 carries lateral flanges 166 which are enclosed in a bearing box 168 encasing a row of spherical bearings 170 along each crevice formed by flanges 166 which free end portion 164.

Stops 172 limit the travel of plate 156. Plate 156 is connected through a pivot pin 174 to one end of a link arm 176 which is pivotally connecting through a slot 178 at its other end to a pin 180 on block 162. Spring valve 52 projects through an aperture 182 located in arm 176 between pivot pins 174 and 180.

In the operation of the embodiment of Figs.

11 to 13 the rotation of drive shaft 150 in the forward operation of the vehicle causes plate 156 to move in the direction of arrow 184 by the action of the magnets of band 152 on the magnets of row 158, keeping air valve 52 centred in aperture 182. When the vehicle moves in reverse the rotation of drive shaft 150 in the opposite direction causes plate 156 to move in the same direction which causes link arm 176 to move opening air valve 52 and arming the system of Fig. 9 in the same manner as previously described.

Claims (12)

1. A method of automatically actuating the braking system of a vehicle, comprising the steps of detecting the vehicle contacting an obstruction when the vehicle is moving backwards and thereby generating a signal, sensing the rotational direction of a member which rotates in one direction in the forward direction of movement of the vehicle and in the opposite direction in the reverse direction of movement of the vehicle and arming the system, upon sensing rotation of the member in said opposite direction, for the detector signal to cause brake application.

2. A method as claimed in claim 1 including the step of releasing brake application to the armed mode allowing for movement of the vehicle.

3. A method as claimed in claim 2 including the step of disarming the system when the vehicle moves forward.

4. A motor vehicle braking system comprising detector means, positioned on the vehicle, constructed and arranged to detect the vehicle contacting an obstruction where the vehicle is moving backwards and generating a signal on said contact, sensor means effective to sense the rotational direction of a member which rotates in one direction in the forward direction of movement of the vehicle and in the opposite direction in the reverse direction of movement of the vehicle, said sensor means serving, upon sensing rotation of the member in said opposite direction, to arm the system enabling the detector signal to cause brake application and means actuable by the detector signal to cause brake application.

5. A braking system as claimed in claim 4 including means to release brake application to the armed mode for movement of the vehicle.

6. A braking system as claimed in claim 5 including means to disarm the system when the vehicle moves forward.

7. A braking system as claimed in claim 4 in which the means to cause brake application is pneumatic.

8. A braking system as claimed in claim 4 in which the sensor means comprises a pair of spaced opposed interacting magnet means, one mounted on an element of the vehicle and movable therewith and the other mounted on a fixed element of the vehicle.

9. A unit connectable to a braking system of a vehicle for automatically actuating the braking system, comprising detector means actuable on rearward movement of the vehicle to generate a signal sensor means constructed and arranged to sense the rearward movement of the vehicle, pneumatic means connected with the sensor means to arm the braking system enabling the detector signal to cause brake application on said rearward movement and pneumatic means actuable by the detector signal to cause said brake application.

10. A unit as claimed in claim 9 in which the sensor means is constructed and arranged to sense the rotational direction of a member which rotates in one direction on the forward direction of movement of the vehicle and in the opposite direction on the reverse direction of movement of the vehicle.

11. A unit as claimed in claim 9 in which the detector means is pneumatic.

12. A motor vehicle braking system substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.