GB2082700A

GB2082700A - Method of arresting a vehicle; vehicle having arrestor means

Info

Publication number: GB2082700A
Application number: GB8123363A
Authority: GB
Original assignee: Wheway Watson Holdings Ltd
Current assignee: Mann and Hummel Wheway Ltd
Priority date: 1980-08-06
Filing date: 1981-07-30
Publication date: 1982-03-10
Also published as: GB2082700B

Abstract

A vehicle (10) e.g. a pit tub, is arrested whenever the speed of the vehicle (10) exceeds a threshold value, whereupon an arrestor means (20) which is mounted on the vehicle (10) is actuated whereof an arresting member (22) of said means (20) is moved downwardly to engage with the ground, track or other body relative to which the vehicle (10) is travelling, the arresting member (22) engaging the body to the rear of the centre of rotation (24) of said member (22) that is to the rear of the lowest point at which the arresting member (22) is connected to and receives support from the vehicle (10). Thus, as shown, the member (22) is pivotable downwardly but it could be telescoped downwardly. Speed of vehicle may be sensed by hydraulic pump (33) driven by wheels (16) via belt (32), and a control means responsive to pressure and/or volume pumped releases pressure in a circuit to retract a ram (30) and release control arms (25); speed may be sensed by electrical or other mechanisms. <IMAGE>

Description

SPECIFICATION Method of arresting a vehicle This invention relates to a method of arresting a vehicle and to a vehicle having an arresting means. More particularly, but not exclusively, the invention relates to a method of arresting a vehicle which is adapted to travel on tracks, such as a pit tub of the type used below ground in mine workings to transport coal, debris or other goods or persons, the tub being connected by connectors to further tubs to form a train, the train being towed and controlled by a cable which extends to a stationary engine, where other arresting systems such as brakes have failed.

In mine workings, steep gradients are common and thus the stress to which the cable is put is great, and cables can and do sometimes fail. This results in a run-away pit tube or train, which can cause loss of life.

Brakes and other emergency arresting means may be actuated but these have not always proved effective.

It is therefore an object of the invention to provide a new or improved method of arresting a vehicie, and a vehicle having an arrestor means.

According to one aspect of the invention we provide a method of arresting a vehicle whenever the speed of the vehicle exceeds a threshold value, including the steps of sensing the speed of the vehicle above said threshold value, actuating an arrestor means which is mounted on the vehicle whereof an arresting member of said means is moved downwardly to engage with a body relative to which the vehicle is travelling, to arrest the vehicle, said arresting member engaging the body to the rear of the centre of rotation (as herein defined) of said member.

According to a second aspect of the invention, we provide a vehicle having an arrestor means, said arrestor means comprising an arresting member movable from a retracted position to an extended position in response to the speed of the vehicle as the speed exceeds a threshold value, the arresting member having a portion which, in use, in said extended position, engages a body relative to which the vehicle is travelling to arrest the vehicle, said portion engaging the body at a location rearwardly of the centre of rotation (as herein defined) of said member.

The body may comprise the ground, or, where the vehicle travels on a track, a part of the track such as the sleepers.

It will be appreciated that as the arresting member engages the body whilst the vehicle is travelling that the member will tend to be rotated relative to the vehicle about a centre of rotation.

Where for example, the arresting member is pivotable downwardly, the centre of rotation will be the pivot point or the point at which the arresting member receives support.

Where the arresting member is not pivoted, but for example telescoped downwardly, and when no additional support is provided, the centre of rotation will be the lowest point at which the member is connected to or receives support from the vehicle.

Thus by "centre of rotation" we mean the lowest point at which the arresting member is connected to and receives support from, the vehicle.

In a preferred embodiment however, the member is pivoted downwardly about a pivot which provides the centre of rotation of the member.

In this case the arresting member may be pivotable downwardly from a retracted position wherein the member is clear of the body to permit the vehicle to move freely relative to the body, to an extended position wherein the member engages the body, for example through an angle exceeding 10 .

Where the vehicle is a wheeled vehicle, having for example two pairs of wheels, the wheels being provided in pairs on opposite ends of axles, and the pivot may be located below a plane parallel or substantially parallel to the direction of the vehicle in which the uppermost points of the wheels nearest to said pivot lie, and preferably, the pivot lies in or adjacent a plane parallel or substantially parallel to the direction of the vehicle in which the axis of rotation of said nearest wheels lie.

However, the vehicle may be any other type of vehicle.

The arresting member may be movable downwardly under the influence of gravity, and means may be provided to restrict upward movement of the arresting member after the member has moved downwardly.

The arrestor means may further comprise a control arm connected to the arresting member, and a holding element to retain the control arm in said retracted position when the speed of the vehicle is below the threshold value and release the control element as the speed exceeds the threshold value, thereby freeing the arresting member for said downward movement.

It will be appreciated that as the arresting member engages the body, the arrestor means will be subjected to a considerable shock. By operating the arresting member by a control arm which is released by a holding element of a control means, the holding element will not be subjected to the shock and thus will not be damaged thereby.

The holding element may normally urge the control arm into engagement with a retaining element, the retaining element locating in a recess in the control element.

The holding element may comprise a hydraulic ram received within a cylinder, the ram, when in an extended condition, engaging the control element.

The ram may be maintained in the extended condition by pressurised fluid of a pre-pressurised circuit of a control means and a valve mechanism of the control means releasing the pressure in the pre-pressurised circuit to enable the ram to retract clear of the control element to permit the arresting member to move downwardly, when the speed of the vehicle exceeds a threshold value.

The pressure in the pre-pressurised circuit may be attained by a manual pump.

The speed of the vehicle may be sensed by means comprising a hydraulic pump coupled to one or more of the wheels or the axles so that when the vehicle is travelling, and the wheel and/or axle rotates, the hydraulic pump pumps fluid to the control means and, when the speed of the vehicle exceeds a threshold value, the pressure and/or quantity of fluid pumped by the pump operates the valve mechanism to permit the arresting member to move downwardly.

The vehicle may be provided with two arrestor means, one at each end of the vehicle to ensure maximum arresting effectiveness when the vehicle is travelling in either direction.

The invention is particularly applicable to a track vehicle such as pit tub, in which case the body which the arresting member engages may comprise sleepers of the track and/or ground beneath and/or between the sleepers.

The invention will now be described by way of example with reference to the accompanying drawings wherein: FIGURE 1 is a side view of part of a pit tub having an arrestor means shown in a retracted position, side walls of the vehicle being omitted for clarity; FIGURE 2 is a view similar to Figure 1 with the arrestor means in an extended position.

Referring to the drawings there is shown a vehicle comprising a pit tub 10 having a chassis 11 on which is mounted a container 12 in which bulk material may be transported. The side wall of the container 12 is omitted for clarity, and part of the remainder of the container is shown in dotted lines.

The pit tub 10 is of the type used below ground in mine workings, the pit tub 10 being connected by connectors (not shown) to further pit tubs (not shown) which are together towed and controlled by a cable which extends to a stationary engine.

The pit tub 10 travels on a track 13 which comprises a pair of rails 14 interconnected at intervals by the sleepers 1 5.

The chassis 11 of the pit tub 10 is mounted on a bogie having two pairs of wheels 1 6 mounted for rotation on axles 17, 1 8 which are received within sealed roller bearings (not shown).

The pit tub 10 further comprises a pair of arrestor means adapted to arrest the pit tub 10 when the speed thereof exceeds a threshold value, as hereinafter described.

Each arrestor means 20 comprises a substantially L-shaped arresting member 22 having two limbs 22a, 22b, one limb 22b having a hook formation 21, at one end. The limb 22b of the arresting member 22 is movable downwardly from a retracted position shown in Figure 1 in which the hook formation 21 is raised clear of the track 13 to enable the pit tub 10 to travel freely on the track 1 3, and, when the speed of the pit tub 10 exceeds a threshold value, to an extended position shown in Figure 2 in which the hook 21 is located between the rails 14 and engages sleepers 15 of the track 13 and/or the ground,23 below and between the sleepers 1 5 to arrest the pit tub 10.

Each arresting member 22 is pivotable from the retracted to the extended position about a pivot 24 which is mounted on a bracket 1 9 secured to the chassis 11 of the pit tub 10. The position of the arresting members 22 are controlled by control arms 25 which are pivotally engaged with the arresting members 22 as shown at 26 for rotation relative thereto.

Referring now particularly to Figure 1 wherein the limbs 22b of the arresting members 22 are shown in the retracted position and hence the hook formations 21 are clear of the track 1 3. The control arms 25 each extend from a position substantially centrally of the vehicle downwards to the arresting member and each have a notch recess 27 at the upper end which is engaged by a retaining element comprising a pin 28. The recesses 27 of the control arms 25 are retained in engagement with the retaining pins 28 by means of a holding element comprising a roller 30a of a ram 30 which extends from a hydraulic cylinder 29. The ram 30 is retained in an extended condition against the force of an internal spring 30b by means of fluid pressurised in a prepressurised hydraulic circuit.The circuit extends to a control cabinet which is shown generally at 34.

The ram 30, hydraulic cylinder 29 and prepressurised circuit are all part of a control means which controls both of the arrestor means 20, the control means being operatively connected to the control cabinet 34.

As the pit tub 10 travels along the track 13, the wheels 1 6 will rotate and thus pulleys 31 attached to one of the wheels 1 6 of each pair, will be rotated. The pulleys 31 could alternatively be connected to the axles 1 7, 1 8.

Toothed drive belts 32 are engaged with the pulleys 31 and drive a shaft 33a mounted centrally of the bogie, the shaft 33a being directly connected to a hydraulic pump 33. Thus the pump 33 is operatively driven as the pit tub 10 travels in either direction, and pumps fluid under pressure to the control cabinet 34 via hydraulic pipes (not shown) to operate the control means.

The control means is responsive to the pressure and/or volume of the fluid pumped by the pump 33 which is dependent on the speed at which 'the vehicle is travelling to sense the speed at which the pit tub 10 is travelling either in the direction of the arrow A or in the opposite direction.

When the speed of the pit tub 10 exceeds a threshold value which may be preset into the control means, a valve mechanism within the cabinet 34 is arranged to release the pressure in the pre-pressurised circuit of which the hydraulic cylinder 29 and ram 30 are a part, and thus the ram 30 will retract into the cylinder 29 under the influence of spring 30b.

The control arms 25 will thus, due to their weight and the weight of the arresting member 22 connected thereto, fall downwardly under the influence of gravity and hence the notch recesses 27 of the control arms 25 will disengage the retaining pins 28 to permit the arresting members 22 to rotate about pivots 24 to their extended position as shown in Figure 2, wherein the hook formations 21 engage the sleepers 1 5 of the track 1 3 and/or the ground 23 below and between the sleepers 1 5.

As the arresting members 22 rotate, means comprising uni-rotational ratchets (not shown) attached to the brackets 19 engage with the arresting members 22 to restrict upward movement of the members 22 after they have moved downwardly to their extended positions, as they engage the sleepers 1 5. Further, a stop plate (not shown) is also provided on each of the brackets 1 9 to prevent each of the arresting members 22 from rotating downwards beyond the second position.

Assuming that the pit tub 10 is moving in the direction of the arrow A in the drawings, when the arresting members 22 pivot downwardly the member 22 indicated at R will be the rearmost member and the member 22 indicated at F will be the frontmost member. The members 22 will engage the sleepers 15, and will tend to be rotated about associated pivot 24 but will be prevented from doing so by the uni-rotational ratchet. Thus the member R will be dragged by the pit tub 10 and will, along with the ratchet, be stressed in tension and will arrest pit tub 10 and bring it to a standstill.

The pivot 24 is positioned in a horizontal plane P, which is a small distance below a horizontal plane P2 containing the axis of rotation of the rearmost wheels 1 6 at the rear of the vehicle, and hence the rear wheels 1 6 will be urged downwardly thereby ensuring that the pit tub 10 does not jump from the track 13.

It will be appreciated that if the rails were not level as shown in the drawings, that the planes P1, P2 would be parallel to the rails and not horizontal as described.

To further assist in maintaining the pit tub 10 on the rails when arrested, the pivot 24 is arranged at a level below the centre of gravity of the vehicle.

At the same time as the rear member R engages the sleepers 1 5, the hook formation 21 of the front member F at the end 36 of the pit tub 10, will engage the sleepers 1 5 and tend to ride up over the sleepers 1 5 to lift the front end 36 from the track 13. However, this is not detrimental to the effectiveness of the arresting means 20 at the rear end 35 of the vehicle.

If however the pit tub 10 is travelling in the opposite direction to arrow A, then the end 36 will be the rear end and accordingly, the wheels 1 6 adjacent the end 36 will be urged downwardly towards the track 1 3 by the hook formation 21 as it engages the sleepers 1 5, and the end 35 of the pit tub 10 will lift from the track 13.

It can be seen that by providing the hydraulic cylinder 29 and ram 30 in a pre-pressurised circuit that this provides a fail-safe arrangement as in the event of any pressure failure in the ram 30, cylinder 29 or pre-pressurised circuit, the ram 30 will be retracted, and thus the control arms 25 released, and thus the vehicle will be arrested.

Further, as the ram 30 disengages the control arms 25, and thus the control arms 25 and arresting members 22 can move freely downwardly to their extended position, the substantial shock which will be experienced by the arrestor means 20 as the members 22 engage the sleepers, will not be transmitted to the hydraulic ram or the rest of the control means thereby avoiding damage thereto. The members 22 and arm 25, are constructed so as to be capable of withstanding the shock.

To reset the arrestor means 20 to permit the pit tub 10 to be used again, socket recesses 40 are provided in the pivots 24 whereby a socket tool may be engaged with the recesses 40 to release the ratchets and return the arresting members 22 and control elements 25 to their Figure 1 positions.

The pre-pressurised circuit may then be reprepressurised by means of a manual pump (not shown) to extend the ram 30 and re-engage the retaining pins 28 in their notch recesses 27.

Although downward movement of the arresting members 22 has been described as being pivotable, if desired, the members may move downwardly in any other manner. For example, the members may be telescopic and may telescope downwardly to the extended position.

Further, although in the embodiment described, the members 22 have been described as tending to rotate about a centre of rotation which corresponds to the pivot 24 as the members 22 engage the sleepers 15 and/or rail 43 in a telescoping arrangement for example, the centre of rotation will be the lowermost point at which the members are connected to the vehicle.

Although the invention has been described with reference to a pit tub 10, if desired, the invention may be applied to any other track or road vehicle.

Further, it is not necessary for the hook formation 21 to engage sleepers of a track 13, but they may engage the ground, or means associated with the ground or the track to arrest the vehicle, or any other body relative to which the vehicle moves as it travels.

Although the mechanism for releasing the pressure in the pre-pressurised circuit and the speed sensitive means have been described as being hydraulic, if desired a suitable electrical circuit and switch arrangement or any other mechanism may alternatively be employed.

Claims

1. A method of arresting a vehicle whenever the speed of the vehicle exceeds a threshold value, including the steps of sensing the speed of the vehicle above said threshold value, actuating an arrestor means which is mounted on the vehicle whereof an arresting member of said means is moved downwardly to engage with a body relative to which the vehicle is travelling, to arrest the vehicle, said arresting member engaging the body to the rear of the centre of rotation (as herein defined) of said member.

2. A vehicle having an arrestor means, said arrestor means comprising an arresting member movable from a retracted position to an extended position in response to the speed of the vehicle as the speed exceeds a threshold value, the arresting member having a portion which, in use, in said extended position, engages a body relative to which the vehicle is travelling to arrest the vehicle.

said portion engaging the body at a location rearwardly of the centre of rotation (as herein defined) of said member.

3. The invention according to Claim 1 or Claim 2 wherein the body comprises the ground, or, where the vehicle travels on a track, a part of the track such as the sleepers.

4. The invention according to any one of Claims 1 to 3 wherein the arresting member is pivotable downwardly about a pivot which provides the centre of rotation of the member.

5. The invention according to any one of Claims 1 to 3 wherein the arresting member is telescoped downwardly, from a support point which provides the centre of rotation of the member.

6. The invention according to Claim 4 wherein the arresting member is pivotable downwardly from a retracted position wherein the member is clear of the body to permit the vehicle to move freely relative to the body, to an extended position wherein the member engages the body.

7. The invention according to Claim 4 or Claim 6 wherein the vehicle is a wheeled vehicle, the wheels being provided in pairs on opposite ends of axles, and the pivot is located below a plane parallel or substantially parallel to the direction of the vehicle in which the uppermost points of the wheels nearest to said pivot lie.

8. The invention according to Claim 7 wherein the pivot lies in or adjacent a plane parallel or substantially parallel to the direction of the vehicle in which the axis of rotation of said nearest wheels lie.

9. The invention according to any one of the preceding claims wherein the arresting member is movable downwardly under the influence of gravity, means being provided to restrict upward movement of the arresting member after the member has moved downwardly.

10. The invention according to any one of the preceding claims wherein the arrestor means further comprises a control arm connected to the arresting member, and a holding element to retain the control arm in a retracted position when the speed of the vehicle is below the threshold value and release the control element as the speed exceeds the threshold value, thereby freeing tbe arresting member for said downward movement.

11. The invention according to Claim 10 wherein the holding element normally urges the control arm into engagement with a retaining element, the retaining element locating in a recess in the control element.

12. The invention according to Claim 10 or Claim 11 wherein the holding element comprises a hydraulic ram received within a cylinder, the ram, when in an extended condition, engaging the control element.

13. The invention according to Claim 12 wherein the ram is maintained in the extended condition by pressurised fluid of a pre-pressurised circuit of a control means and a valve mechanism of the control means releasing the pressure in the pre-pressurised circuit to enable the ram to retract clear of the control element to permit the arresting member to move downwardly, when the speed of the vehicle exceeds a threshold value.

14. The invention according to Claim 13 wherein the pressure in the pre-pressurised circuit is attained by a manual pump.

1 5. The invention according to Claim 13 or Claim 14 wherein the speed of the vehicle is sensed by means comprising a hydraulic pump coupled to one or more wheels or axles so that when the vehicle is travelling, and the wheel and/or axle rotates, the hydraulic pump pumps fluid to the control means and, when the speed of the vehicle exceeds a threshold value, the pressure and/or quantity of fluid pumped by the pump operates the valve mechanism to permit the arresting member to move downwardly.

16. The invention according to any one of the preceding claims wherein the vehicle is provided with two arrestor means, one at each end of the vehicle to ensure maximum arresting effectiveness when the vehicle is travelling in either direction.

17. The invention according to any one of the preceding claims wherein the vehicle is a track vehicle such as pit tub, in which case the body which the arresting member engages comprises sleepers of the track and/or ground beneath and/or between the sleepers.

1 8. A method of arresting a vehicle, substantially as hereinbefore described with reference to Figure 1 and Figure 2 of the accompanying drawings.

19. A vehicle substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

20. Any novel feature or novel combination of features described herein and/or shown in the accompanying drawings.