GB2048404A

GB2048404A - Rail car retarder

Info

Publication number: GB2048404A
Application number: GB8005251A
Authority: GB
Original assignee: Dale Mansfield Ltd
Current assignee: Dale Mansfield Ltd
Priority date: 1979-02-17
Filing date: 1980-02-15
Publication date: 1980-12-10
Also published as: GB2048404B

Abstract

A rail car retarder includes an arrester having an abutment member 16 normally held down by a release means 26 out of the path of travel of a rail car and friction means (e.g. pad 14) engageable with beam 10 to restrict its movement therealong the release means 26 being actuable to allow the abutment member 16 to swing into the path of travel of an overspeed rail car by a speed sensitive pawl arrangement Fig. 3 which is operable on being struck by an over- speed rail car. As shown, the pawl arrangement comprises a pawl 52 which is rotatable by an overspeed rail car to cause an anvil member 72 to pivot a lever arrangement 84 to move a release link 38 connected to release means 26. The pawl arrangement is provided uphill of the arrester, a predetermined distance from a stop 40 on beam 10, which stop 40 defines the normal position of abutment member 16. <IMAGE>

Description

SPECIFICATION An improved rail car retarder The invention relates to rail car retarders. The invention is intended for use primarily but not exclusively in mines where rail cars are moved up and down gradients, normally by haulage ropes. The retarder is intended to act as a safety device which retards any rail car moving down the gradient at above a predetermined speed which is sensed by the retarder. A rail car moving faster than said predetermined maximum speed will be referred to hereinafter as ''an overspeed rail car".

According to the present invention there is provided a rail car retarder including a fixed beam with an arrester mounted thereon and a speed sensitive pawl arrangement associated with the arrester to cause the arrester to assume an active position when an overspeed rail car passes said pawl arrangement, the arrester including friction means engageable with said beam to restrict its movement therealong, an abutment means movable into the path of travel of an overspeed rail car on actuation of the arrester and release means connected to said pawl arrangement whereby they release said abutment means when the pawl arrangement is passed by an overspeed rail car.

Preferably the abutment means is pivotally mounted on the arrester and the release means is rigidly mounted on the solid beam whereby the release means only engages the abutment means to hold it out of the path of travel of rail cars when the arrester is in a predetermined position.

Preferably the abutment means is pivotally mounted to the arrester and is spring biased into said rail car engaging position. The spring biasing means may be hair-pin type springs. Stop means may be provided on the beam to contact the arrester when it occupies said predetermined position at which the release means are engageable. The release means may include a catch pivotally mounted with respect to the beam and engageable in a notch in the abutment means when it is moved out of its rail-car engaging position against the bias of the springs.

The abutment means may be provided with a longitudinally extending groove to permit the passage of a haulage rope for the rail cars therethrough .

Preferably the speed sensitive pawl arrangement includes a framework fixed in position relative to said solid beam and having a pawl pivotally mounted thereon, the pawl being counter-balanced such that it normally lies in the path of travel of a rail car, the framework pivotally mounting also an anvil member arranged in the path of pivotal movement of the pawl and connected to said release means of the arrester, the arrangement of pawl and anvil member being such that when an overspeed rail car passes the pawl it is rotated and strikes said anvil member with such force that he anvil member is caused to pivot and actuate said release mechanism.

To control the striking force of the pawl required to pivot the anvil member, the anvil member includes a first arm arranged to one side of its pivot axis in the path of travel of the pawl and a second counter-weighted arm on the other side of said axis. Preferably the connection between the anvil member and the release means of the arrester includes a lever pivotally mounted on the framework of the pawl arrangement, one end of the lever being connected to a rod between the release means and said lever the other end including a pin engageable in an open-ended slot formed in the anvil member.

Preferably the speed sensitive pawl has a first arm intended to project into the path of travel of a rail car and a second arm diametrically opposite to said first arm and including a striking surface adapted to contact the anvil member. The anvil member may have a groove formed therein to permit passage of the first arm of the pawl therethrough.

The mass of the second arm of the pawl and its distribution is so arranged than when a rail car passing the pawl at a speed which is less than said overspeed strikes the pawl it does not pivot sufficiently or with sufficient speed to cause corresponding pivotal movement of the anvil member but rather returns to its original position ready to encounter a further rail car.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is an elevation of an arrester of a rail car retarder; Figure 2 is an end view of the arrester showing the beam on which it is mounted; Figure 3 is an elevation of a speed sensitive pawl arrangement for use with the arrester of Figs. 1 and 2; and Figure 4 is an end elevation of the speed sensitive pawl arrangement.

A rail car arrester is mounted on a solid 1- section beam 10 rigidly mounted between the rails on a gradient up and down which rail cars travel. The arrester includes a framework 12 straddling the beam and in the present embodiment two pairs of friction pads 14 carried by the framework at corresponding locations on opposite sides of the web of the beam and urged by resilient means (not shown) against the beam. It will be realised that any tendancy for the arrester to move along the beam will be restricted by the frictional forces between the pads 14 and the web of the beam. It is this frictional force which is utilised to retard an overspeed rail car.

To arrange for this retardation it is necessary to temporarily connect the rail car with the arrester and to this end the arrester is provided with an abutment member 16 pivotally mounted thereon about an axle 19, the abutment member having a first contact face 18 intended to abut the rail car and a rear face 20 inclined downwardly from the front or contact the face. The abutment member 16 is substantially U-shaped and is spring biased towards the position shown in full lines in Fig.

1, that is into the path of travel of the rail car, by two pairs of hair-pin type springs 22 mounted around the axle 19 and engaging, at their opposite ends, the abutment member 16 a.nd framework 12 respectively.

An extension 24 is provided on the front face 18 of the abutment member, the extension 24, as illustrated in Fig. 1, being adapted to abut a portion of the framework 12 to limit its upward movement.

To allow for the free passage of rail cars past the arrester the. abutment member is pivoted in a clockwise direction, as viewed in Fig. 1, into the position shown in Fig. 1 in phantom lines and is normally retained in this position by a release means 26 mounted on the beam. The release means includes a mount 28 fixed to the beam and on which is pivotally mounted on either side thereof a paìr of arms 30 carrying between them at their free ends a catch rod 32 adapted to engage over a catch surface 34 formed on the extension 24 from the abutment member 16.A coil spring 36 attached to a link 38 fixed to the catch rod 32 biases the catch rod 32 into its engaging position and it will .be realised from the description given above with reference to the drawing that if it is desired to release the abutment member so that it swings into the path of travel of a rail car it is necessary to pull on the link 38 towards the right of Fig. 1 to disengage the bar 32 from the engagement surface 34 of the abutment member which is then free to travel upwards into the position shown in full lines in Fig. 1 under the action of the hairpin springs 22.In this position it lies in the path of travel of a rail car which, on striking it causes it to move along the beam, towards the left as viewed in Fig. 1, against the frictional forces exerted by the friction pads 14, the rail car thus being eventually stopped.

It will be further realised that since the release means 26 is fixed to the beam the abutment member cannot be fixed in an inoperative position until it is returned to the position on the beam shown in Fig. 1 and to assist an operator in locating this position stop 40 is provided on the beam 10.

A speed sensitive pawl arrangement is provided up-hill of the arrester to detect the speed of rail cars passing thereby and, on detecting an overspeed rail car, to cause the release means 28 to allow the abutment member 16 to swing into the path of travel of said rail car such that when it reaches the arrester it contacts the abutment member and is retarded as described above. The speed sensitive pawl arrangement is fixed in position between the rails at a predetermined distance from the stop 40 on the beam and comprises an inverted substantially U-shaped framework 50 between which a speed sensitive pawl 52 is rotatably mounted on an axle 54. The pawl comprises a first arm 56 and diametrically opposite thereto a pair of spaced apart second arms 58.The first arm 56 has a first substantially flat contact face 60 and a curved rear face 62 and it will be realised that a rail car passing the pawl in either direction will cause it to pivot, anti-clockwise as viewed in Fig. 3 when the rail car is passing down the gradient and clockwise when it is passing up the gradient. The pair of second arms 68 similarly have a flat front surfaces 64 and a curved rear surface 68 terminating in a striking surface 70, the purpose of which will be described below.

An anvil member 72 is also pivotally mounted on the framework 50 about an axle 74 and also has two pairs of arms 76, 78 the latter acting as a counter-weight and the former being arranged in the path of travel of the contact surface 70 of the pawl 52.

In the lower surface of the anvil member there is formed an open-ended slot 80 which accommodates a bar 82 carried by a lever arrangement 84 pivotally mounted about an axis 86 on the framework 50. The end of the lever arrangement 84 opposite from that carrying the pin 82 is adapted for connection to a rod which interconnects the link 38 of the release means 28 of the arrester and the lever arrangement 84.

In operation, when a rail car passes the pawl arrangement at a speed below overspeed it pivots the pawl 52 out of its way and owing to the counter-balancing effect of the arms 58 it returns to its original position as shown in Fig. 3 as soon as the car passes. On the other hand, if an overspeed rail car passes the pawl arrangement it causes the pawl to rotate at such a speed that it has sufficient energy when the contact surfaces 70 strike the arms 76 of the anvil member to cause the anvil member to pivot against its counter-ballancing arm 78 to pivot the lever arrangement 84 and consequently move the release link 38. In a situation where the pawl is rotated by a rail car at such a speed that it causes the contact surfaces 70 to strike the arm 76 of the anvil member with insufficient force to pivot the anvil member the geometry and distribution of mass of the pawl member is such that it remains in this position such that the next succeeding part of the rail car, for example its next axle, abuts the face 64 of the arms 58 of the pawl and forces the anvil member to .pivot, thus moving the lever arrangement 84 to cause the release of the abutment member 16.

Various modifications may be made without departing from the scope of the invention as defined in the claims, for example a groove 90 (Fig. 2) may be formed in the rear face 20 of the abutment member to allow it to clear the haulage rope for the rail cars when it moves to its upper position. Various other friction arrangements acting on the fixed beam may be employed and various designs of release mechanisms from the abutment member could be used. Similarly alternative spring means could be used for biasing the various spring urged components of the retarder, for example the abutment member and the release means.

Claims

1. A rail car retarder including a fixed beam with an arrester mounted thereon and a speed sensitive pawl arrangement associated with the arrester to cause the arrester to assume an active position when an overspeed rail car passes said pawl arrangement, the arrester including friction means engageable with said beam to restrict its movement therealong, an abutment means movable into the path of travel of an overspeed rail car on actuation of the arrester and release means connected to said pawl arrangement whereby they release said abutment means when the pawl arrangement is passed by an overspeed rail car.

2. A retarder as claimed in claim 1, in which the abutment means is pivotally mounted on the arrester and the release means is rigidly mounted on the solid beam whereby the release means only engages the abutment means to hold it out of the path of travel of rail cars when the arrester is in a predetermined position.

3. A retarder as claimed in claim 1 or claim 2, in which the abutment means is pivotally mounted to the arrester and is spring biased into said rail car engaging position.

4. A retarder as claimed in claim 3, in which the spring biasing means is hair-pin type springs.

5. A retarder as claimed in any one of claims 2 to 4, in which the release means includes a catch pivotally mounted with respect to the beam and engageable in a notch in the abutment means when it is moved out of its rail-car engaging position against the bias of the springs.

6. A retarder as claimed in any one of claims 1 to 5, in which the abutment means is provided with a longitudinally extending groove to permit the passage of a haulage rope for the rail cars therethrough.

7. A retarder as claimed in any one of the preceding claims in which the speed sensitive pawl arrangement includes a framework fixed in position relative to said solid beam and having a pawl pivotally mounted thereon, the pawl being counter-balanced such that it normally lies in the path of travel of a rail car, the framework pivotally mounting afso an anvil member arranged in the path of pivotal movement of the pawl and connected to said release means of the arrester, the arrangement of pawl and anvil member being such that when an overspeed rail car passes the pawl it is rotated and strikes said anvil member with such force that the anvil member is caused to pivot and actuate said release mechanism .

8. A retarder as claimed in claim 7, in which to control the striking force of the pawl required to pivot the anvil member, the anvil member includes a first arm arranged to one side of its pivot axis in the path of travel of the pawl and a second counter-weighted arm on the other side of said axis.

9. A retarder as claimed in claim 8, in which the connection between the anvil member and the release means of the arrester includes a lever pivotally mounted on the framework of the pawl arrangement, one end of the lever being connected to a rod between the release means and said lever the other end including a pin engageable in an openended slot formed in the anvil member.

10. A retarder as claimed in any one of claims 7 to 9, in which the speed sensitive pawl has a first arm intended to project into the path of travel of a rail car and a second arm diametrically opposite to said first arm and including a striking surface adapted to contact the anvil member.

11. A retarder as claimed in any one of claims 7 to 10, in which the anvil member has a groove formed therein to permit passage of the first arm of the pawl therethrough.

12. A retarder as claimed in claim 10 or claim 11, in which the mass of the second arm of the pawl and its distribution is so arranged that when a rail car passing the pawl at a speed which is less than said overspeed strikes the pawl it does not pivot sufficiently or with sufficient speed to cause corresponding pivotal movement of the anvil member but rather returns to its original position ready to encounter a further rail car.

13. A rail car retarder substantially as hereinbefore described with reference to the accompanying drawings.

14. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.