GB2123590A

GB2123590A - Rail car sensor

Info

Publication number: GB2123590A
Application number: GB08220346A
Authority: GB
Inventors: Eric Dring
Original assignee: Dale
Current assignee: Dale
Priority date: 1982-07-13
Filing date: 1982-07-13
Publication date: 1984-02-01
Also published as: GB2123590B

Abstract

A rail car sensor adapted for location between a pair of rails and actuable on passage of a flanged wheel past the sensor includes an electrical switch and means for actuating the switch. A first lever rotatably mounted about a substantially vertical axis is connected to said switch actuating means and at least one connecting rod extending between the lever and an arm pivotally mounted about an axis parallel to the axis of the lever and in such a way that the arm is adapted to lie alongside the inner face of a rail, whereby on passage of a flanged wheel along the rail the arm is pivoted about its axis causing pivotal movement of the lever and actuation of the electrical switch. <IMAGE>

Description

SPECIFICATION Improved rail car sensor The present invention relates to an improved rail car sensor, that is a device for sensing the passage of a rail mounted vehicle at a specified position.

The present invention is especially but not exclusively intended for use with rail systems in mines where the arduous working conditions are such that rail car sensors normally employed on railway systems are not suitable.

It is important for the safe operation of the mine rail system that an indication is given when a particular length of track is occupied by a train.

Additionally, certain safety measures employed on the mine system require sensors so that they may be activated or de-activated, as the case may be.

Many of the modern high technology units such as magnetic proximity switches, ultra-sonic devices, light beams and photo cells have been tried and have given an indifferent performance owing to the harsh environment. In most cases such systems have been converted back to some form of mechanical/electrical switch after failures have been experienced.

It is apparent that the only common part of the wide variety of mine vehicles used under ground that can be sensed is the wheel flange and consequently all of the present switches available actuate by being pressed down by the wheel flange and are known as treadle switches. These units suffer from certain disadvantages which make their use inadvisable in a mine roadway. For instance some are not sufficientiy robust and others involve components located between the rails.

In summary, therefore, the prior arrangements suffer from the following disadvantages: 1) They are vulnerable to mechanical damage.

2) They can be accidentally operated by people walking between the tracks.

3) They can present a hazard to people walking in the dark.

An object of the present invention is to obviate or mitigate these disadvantages.

According to the present invention there is provided a rail car sensor including an electrical switch, movable means for actuating said switch, a first lever rotatably mounted about a substantially vertical axis and connected to said switch actuating means and at ieast one connecting rod extending between said lever and an arm pivotally mounted about an axis parallel to the axis of the lever in such a way that the arm is adapted to lie alongside the inner face of a rail, whereby on passage of a flanged wheel along the rail the arm is pivoted about its axis causing pivotal movement of the lever and actuation of the electrical switch.

Preferably two arms are provided on the device being mounted alongside each rail, each being connected to the lever on opposite sides of its pivot axis by a connecting rod.

Preferably the actuating means comprises a block slidably mounted on a bar, the axis of which is transverse to the longitudinal axis of the rails, coil springs being provided around the baron either side of the block and being so biased that when no force is applied to said lever said actuating means occupies a central position and the arms are equally spaced from the inside facing faces of the rails.

Preferably the electrical switch is a plunger switch having a roller at the outer end of its plunger adapted to move over an inclined track on the actuating means whereby movement of the actuating means in one direction causes actuation of the switch.

Preferably the pivot axes for the arms and lever, together with the bar carrying the actuating member and the switch are mounted on a base plate rigidly connected to RSJ's providing sleepers for the rails as well as a mounting for the base plate.

Preferably a metal cover having inclined ends is provided to cover the sensor.

Preferably the cover plate terminates adjacent the inner facing faces of the rails.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Fig. 1 is a plan view of a rail car sensor Fig. 2 is a side elevation and Fig. 3 is an end elevation.

A rail car sensor is mounted between two rails 10, 1 2 of a mine railway system. The sensor comprises a base plate 1 4 incorporating a pair of longitudinal stiffners 1 6 fixed to its underside and fixed also to a pair of RSJ's 18 arranged to run transversely of the rails 10, 12 and act as sleepers therefor, clamping means 20 being provided for the rails.

An electrical limit switch 22 is supported on the base plate 1 4. The limit switch is intended to give an electrical signal on passage of a rail car past the sensor and the sensor is provided with mechanical means operable by movement of the rail car to cause movement in the longitudinal direction of the track of the operating plunger 24 of the limit switch, this plunger being provided at its free end with a roller 26.

An actuator block 28 is held in contact against the roller 26, the block being mounted on a bar 30 supported at its ends in supports 32 fixed to the base plate 14. Two coiled compression springs 34, 36 are arranged on either side of the actuating block 28 and extend between the block 28 and the supports 32. It will be realised that the springs 34, 36 provide a centering action for the actuator block 28. An inclined face 38 is machined on the face of the actuator block contacting the roller 26 and it will be realised that movement of the block towards the rail 10 will cause the plunger 24 of the limit switch 22 to be depressed thereby giving a signal.

Movement of the actuator block on passage of a rail car past the sensor is caused by a pair of sensing arms moved by the flanges on the rail car wheels and a linkage which will now be described in detail. Two vertical pivot shafts 40 are mounted on the base plate 14 and rotatably support two arms 42 such that the arms lie alongside the rails 10, 12. The edges of the arms 42 adjacent the rails 1 0, 12 are inclined with respect to the inside face of the rails when the arms are in the "centre" position. The arms are arranged such that their tops are substantially level with the tops of the rails 10, 1 2 and that part of the arms closest to the inside faces of the rails are spaced from these inside faces by an amount which is less than the thickness of the flange of the rail car.As a result, it will be realised that a rail car passing the arms in either direction will cause them to progressively pivot away from the inside face of the rails owing to the decreasing gap between the arms and the rails provided by the inclined faces of the arms.

Each arm near its end remote from the shaft 40 is provided with a block 44 on its underside, the block supporting a pivot pin 46 about which a connecting rod 48 is rotatably mounted. The connecting rods 48 for each arm are of the same length and the ends thereof, remote from the pivot pins 46, are pivotably attached by pins 50 to a lever 52 rotatably mounted about a vertical shaft 54 upstanding from the base plate 14. The pivot pins 50 have their centres arranged on a diameter through the shaft 54, equispaced on opposite sides of the centre of said shaft. It will be realised therefore that inward movement of the arms 42 is transmitted by way of the connecting rods 48 to the lever 52 which is caused to pivot in a clockwise direction as viewed in Figure 1.

The free end of the lever 52 is provided with a slot 56 which accommodates a pin 58 projecting upwardly from the actuating block 28. The clockwise movement of the lever which occurs on passage of a rail car past the sensor will result in the movement of the actuating block 28 towards the rail 10 described above and thus actuation of the limit switch 22. When the rail car has passed the sensor the springs 36 will cause the entire assembly to return to its "centre" position awaiting the next rail car.

To protect the arrangement against damage a chequered plate cover 60 having inclined ends 62 is fixed to the base plate 14 by bolts 64. This allows personnel walking between the rails to pass over the sensor without danger. The cover plate 60 does not extend over the entire device as it must leave an area of the arms 42 exposed but it will be realised that owing to the fact that the arms pivot inwardly as opposed to downwardly even if some arrangement is pushed down on the arms 42 they will not actuate the limit switch accidentally.

Various modifications can be made without departing from the scope of the invention, for example the structural assembly can be altered in many ways. Only one arm need be employed.

Additionally many linkages of different designs can be employed to connect the arms and the actuating block is provided that in the case of a plunger limit switch movement of the arms causes movement of the plunger. If an alternative form of limit switch is employed then an alternative linkage giving a different but suitable output movement can be utilised.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to whether or not particular emphasis has been placed thereon.

Claims

1. A rail car sensor including an electrical switch, movable means for actuating said switch, a first lever rotatably mounted about a substantially vertical axis and connected to said switch actuating means and at least one connecting rod extending between said lever and an arm pivotally mounted about an axis parallel to the axis of the lever in such a way that the arm is adapted to lie alongside the inner face of a rail, whereby on passage of a flanged wheel along the rail the arm is pivoted about its axis causing pivotal movement of the lever and actuation of the electrical switch.

2. A sensor as claimed in Claim 1, in which two arms are provided on the device, being mounted alongside each rail, each being connected to the lever on opposite sides of its pivot axis by a connecting rod.

3. A sensor as claimed in Claim 2, in which the actuating means comprises a block slidably mounted on a bar, the axis of which is transverse to the longitudinal axis of the rails, coil springs being provided around the bar on either side of the block and being so biased that when no force is applied to said lever said actuating means occupies a central position and the arms are equally spaced from the inside facing faces of the rails.

4. A sensor as claimed in any one of Claims 1 to 3, in which the electrical switch is a plunger switch having a roller at the outer end of its plunger adapted to move over an inclined track on the actuating means whereby movement of the actuating means in one direction causes actuation of the switch.

5. A sensor as claimed in any one of Claims 2 to 4, in which the pivot axes for the arms and lever, together with the bar carrying the actuating member and the switch are mounted on a base plate rigidly connected to RSJ's providing sleepers for the rails as well as a mounting for the base plate.

6. A sensor as claimed in any one of the preceding Claims, in which a metal cover having inclined ends covers the sensor.

7. A sensor as,claimed in Claim 6, in which the cover plate terminates adjacent the inner facing faces of the rails.

8. A rail car sensor substantially as hereinbefore described with reference to the accompanying drawing.

9. Any novel subject matter or combination including novel subject matter herein described, whether or not within the scope of or relating to the same invention as any of the preceding Claims.