US3622021A

US3622021A - Safety latches for rotary car dumper

Info

Publication number: US3622021A
Application number: US859419A
Authority: US
Inventors: Donald J Heath; Walter L Lopatka; James W Petrie
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1969-09-19
Filing date: 1969-09-19
Publication date: 1971-11-23
Anticipated expiration: 1988-11-23

Abstract

A rotary car dumper which inverts a laden rail car and of the type having clamps to lock it in an invertible cradle is provided with gravity-operated safety latches. In the event the clamp holding mechanisms fail, the safety latches provide positive retention of the clamps so that the car can be safely returned to its upright position.

Description

PATENTEBmJv 23 i97l SHEET 1 0F 4 I N VILN H )RS DONALD J. HEATH WALTER L. LOPATKA JAMES W PETRIE A T TORNE YS PATENTEDuuv 23 Ian SHEET b [1F 4 SAFETY LATCHES FOR ROTARY CAR BUMPER BACKGROUND OF THE INVENTION The present invention pertains to railcar dumpers which invert a laden car to dump its contents. More specifically, the invention concerns those types of car dumpers which use a rotary cradle to support the upright car and have cable-operated clamps that either partially or fully span the open upper side of the car to support the car when the dumper is inverted.

Generally the contents of the car are dumped before the car is inverted 180 and the only load on the clamp-holding cables or ropes is the empty car. However, if the contents of the car are frozen, the holding cables have to support both the load of the material and the inverted car. Lack of proper cable maintenance can in time cause a cable failure under the condition just mentioned and result in the dropping of the inverted, loaded car. The mechanical safety latches of the present invention provide positive retention of the clamps if the cables fail, so that the car can be safely returned to the upright position and removed from the dumper.

The present trend is toward larger capacity cars and greater payload. To provide for this, a greater than normal number of car clamps are usually used so as to increase the factor of safety and prevent damage to car and/or dumper in the event of failure. The addition of the safety latches of this invention is a simpler and more economical means of furnishing the required added protection than providing extra car clamps.

SUMMARY OF THE INVENTION A pair of gravity-operated safety latches are pivotally mounted on the fixed frame portion of the leading side of the cradle relative to the direction in which the cradle rotates toward an inverted dumping position, and in straddling relation to the plane of movement of a beam clamp. Lateral abutments of the beam lie in the plane of movement of the latches and an abutment ledge on each latch moves into underlying relation with an abutment as the gravitating latch swings relative to the inverting cradle. Similar gravity-operated latches are pivoted to the beam clamp at its other end and coact with abutments carried by the fixed frame portion of the cradle. It is therefore the object of the present invention to provide mechanism for locking the clamp arm of a rotary car dumper by pivotal latches which are urged by gravity into positive locking relation to the clamp arm when the dumper is inverted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of one type of rotary car dumper incorporating the safety latches of the present invention.

FIG. 2 is a fragmentary diagrammatic perspective illustrating one of the beam clamps shown in FIG. 1 with its safety latches and associated frame structure.

FIG. 3 is a fragmentary diagrammatic perspective of a beam clamp and safety latch arrangement, and the actuating mechanism for the clamp.

FIG. 3A is a fragmentary view in elevation of a portion of the actuating mechanism for the clamps.

FIGS. 4-7 are diagrammatic end elevations of the FIG. 1 car dumper, and illustrate successive operational positions from the beginning to end of a car-dumping operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT As above indicated, the present invention may be advantageously used with various rotary car dumpers presently being used. One such car dumper (FIG. 1) used with cars of constant height, as in unit train operation, includes the conventional transversely U-shaped rigid cradle structure 12 that interconnects

end rings

14 and 16 which are supported on wheels 18in a pit 20. A railcar R is moved in the direction of the arrow 22 onto rails 24in the cradle, following which the cradle is rotated in the direction of the arrow 26 until the car is substantially inverted and its contents drop into the pit for removal by a conveyor or other apparatus.

in attaining the inverted position, an initially overhead beam clamp 30 at each end portion of the cradle 12 moves automatically into clamping relation with the upper edge portions of the sidewalls of the railcar. In the ordinary car dumper the mechanism which operates the two beam clamps provides the sole support of the inverted car. In the present apparatus, the beam clamps are mechanically locked in place by pairs of

safety latches

32 and 34 which in conjunction with the beam clamps 30, can assume, if necessary, the entire weight of a laden car. In the ordinary dumper, if the clamp-operating mechanism breaks, the car can be dropped and damaged, whereas in the present instance the safety latches lock and prevent damage to the clamps. Because the clamps cannot release when the latches are active, no damage to the car can occur and the car, even though it may not dump, can be safely removed from the dumper.

With continued reference to FIG. 1 and to the general and known operating principles of the rotary car dumper 10, a reversible motor M drives a gearbox 33 that is connected to aligned power shafts 35 which each power a cable drum 36. A cable 38 on each drum is trained around the associated

end ring

14 or 16 to efiect rotative movement of the cradle 12.

Each beam clamp 30 is operated by individual mechanism at 40 which lies in the plane of the clamp beam, and the ensuing descriptionis typical of either clamp mechanism. The cradle 12 includes a fabricated initially upright guide post 42, best shown in FIG. 2, which is engaged by slidable clamp beam carriage 44. A horizontal pivot shaft 46 is mounted on the carriage 44 and pivotally carries one end portion of the beam clamp 30. A stop 47 on the carriage 44 limits downward pivotal movement of the clamp 30 so that the beam declines slightly and its free end portion contacts the railcar first. Clamping contact is made at that side of the railcar by a pad 48, and at the other side by a pad 50.

The beam clamps 30 automatically engage the railcar as the cradle 12 rotates. For this purpose, the free end of the clamp 30 (FIG. 3) carries a pair of sheaves 52 which individually guide clamp-holding cables 54 that are anchored to the cradle through an equalizer bar at 56. Extending through the beam, the cables 54 are trained over another pair of sheaves 58, and downward through the carriage 44. Trained around lower sheaves 60, the clamp-holding cables 54 then extend upward and are wound and anchored to individual portions of a winding drum 62 which moves with the cradle 12.

The winding drum 62, in an advanced rotative position of the cradle 12, is rotated in a clockwise direction by a massive counterweight 64, a ratchet wheel 66, and a pawl 68. The counterweight swings free from the winding drum shaft. Pawl 68 is pivoted to the counterweight at 70 and is arranged to rotate the winding drum 62 in a clockwise direction after about 42 of rotation of the cradle 12 to the position shown in FIG. 6. As shown in FIG. 3A, the pawl 68 is part of a lever 72 which is biased at one end by a spring 74 in a direction urging the pawl into contact with the ratchet wheel 66. At its other end the lever carries a roller 76 which is selectively engageable by a shoe 78 to disengage the pawl. Shoe 78 is mounted on an arm 80, that is pivoted to a shaft 82, and is connected to a line 84. The shaft 82 is fixed in the frame which supports the winding drum and extends across the plane of movement of the counterweight 64 to form a stop which limits movement of the counterweight when the cradle 12 is upright.

The link 84 is connected to a bellcrank 86 which has a roller 88 that rides on a short, arcuate, fixed cam track 90. A compression spring 92 urges the link 84 upward, and thus urges the roller 88 toward the cam track 90. In the upright position illustrated in FIG. 3, the bellcrank 86 is held by the cam track in a position in which the link 84 is in its downward position, thus causing the shoe 78 (FIG. 3A) to push upward against the roller 76 to hold the pawl 68 in a released position.

A bracket 94 (FIG. 3) carries the bellcrank 86 and moves with the cradle 12 away from a fixed stop 95. Also mounted on the bracket 94 is a sheave 96 which is engaged with a length of drum winding cable 98. One end of the drum winding cable is wound clockwise around andanchored to a central part of the winding drum 62. The other end of the cable 98 is secured to the lower end of a clamp-lifting carriage 100. A carriage-lifting cable 102 extends from the other end of the carriage 100 counterclockwise around and is anchored to another portion of the winding drum.

Carriage 100 has guide rollers that roll inside a generally tubular, arcuate guide 104, that is best shown in FIG. 5, and is provided with an abutment nose 106 which projects from the guide 104 and is arranged to strike the top end of a fixed stop member 108. Because the abutment nose 106 is engaged with the stop member 108 and the cable 98 extends clockwise around the winding drum, the winding drum cannot rotate in a clockwise direction when the cradle 12 is upright. One end portion of a clamp-lifting cable 110 is wound counterclockwise around and anchored to the winding drum 62, and the cable 110 is trained over a sheave 112 on the guide post 42, and around a sheave 114 which is connected to the clamp beam carriage 44, and upward over a second sheave 112. Below the latter sheave the cable is anchored to the guide post 42. The clamp beam 30 in its raised FIG. 3 position is supported by the cable 110 because the winding drum 62 is locked against clockwise rotation as previously described.

It will now be apparent that as the cradle 12 rotates (counterclockwise) away from its FIG. 3 and 4 upright position, the drum-winding cable sheave 96 moves upward and the clamplifting carriage 100 remains engaged with the stop member 108, thus releasing the winding drum 62 so it rotates clockwise and pays out the cable 110. Accordingly, the clamp beam carriage 44 is lowered by gravity toward the car R, and at about l3 of rotation (the FIG. 5 position) the pad 48 of the beam clamp 30 will contact the upper edge of the car.

At approximately 42 of rotation (the FIG. 6 position) the roller 88 of the bellcrank 86 is beyond the arcuate section of cam track 90 and is free to move outward. The spring 92 thus urges the link 84 upward and the spring 74 causes engagement of the pawl 68 with the ratchet wheel 66. At this time the counterweight is free of the shaft 82. Continued rotation of the cradle 12, accordingly, causes the counterweight 64 to rotate the winding drum clockwise. This will cause the clamplifting cable 110 (FIG. 3) to pay out from the winding drum.

When the cradle 12 has rotated 90 from its initial position the winding drum 62 is at top dead center (a position not illustrated) and further rotation toward dumping position causes a counterweight 116 (FIGS. 3 and 6) to set a band brake 118 that locks the winding drum from further rotation. Before the brake comes into action at 90, the counterweight 64 has rotated approximately 42 about its pivot axis, thus turning the winding drum clockwise the same 42. This action takes up the clamp-holding cables 54 to force the clamp beam 30 against the railcar R.

From the described 90 position to the fully inverted position shown in FIG. 7 the railcar R is locked in the cradle and if the material in the car is loose, it begins to dump into the pit 20. Dumping is usually completed by the time the dumper has rotated to a I60 position. If the clamp-holding cables 54 have been properly maintained, inspected, and replaced at proper intervals, they will safely hold the full weight of an inverted railcar plus its contents. Thus, even if the contents of a car happen to be frozen and do not dump, the car can be safely returned to its initial position and removed from the dumper. If the cables have not been properly maintained, there is a danger that they might break so that the beam clamps 30 are inoperative when supporting either a full or empty car. In the present case, the safety latches 32 and 34 lock the beam clamps 30 so that the car cannot drop. Ordinary car dumpers without the latches or other safety devices have shown that the results can be hazardous to personnel and extremely destructive to the car and to the dumper apparatus, not to mention the attendant cost and inconvenience in removing the car and repairing the damage.

With a beam-clamp type of rotary car dumper using the safety latches of the present invention, the free end of each beam clamp 30 is provided with a laterally projecting abutment member 120 in the plane of each of the safety latches 32. The two latches 32 are pivotally mounted on aligned stub shafts 122, only one of which is shown, that are held by brackets 124 on a fixed longitudinal frame member 126 which is a part of the rotatable cradle 12. Each latch 32 is of generally inverted L-shape and is overbalanced outwardly against a stop 128 when the cradle 12 is in its initial upright position. When the cradle is inverted, an abutment ledge portion 129 of each latch 32 underlies the adjacent abutment member 120.

The latches 34 are mounted for free rotation on outer projections of a shaft 130 which carries the sheaves 58. When the cradle 12 is upright (FIG. 4), each latch 34 is substantially horizontal and rests upon a stop block 132 that projects from the carriage 44. An adjacent abutment 134 on the fixed guide post 42 is arranged to underlie a ledge portion 136 of the latch 34 when the cradle 12 is inverted after the beam clamp 30 is engaged with the car.

With reference to FIGS. 4-7, each pair of the safety latches 32 and 34 cooperate with the car dumper in the following manner. A railcar R is positioned lengthwise in the dumper. If the car is part of a unit train, its couplers are on the rotational axis A of the car dumper, and it need not be uncoupled from the train. Cars which have their couplers displaced from the axis A must be uncoupled. In either case, the safety latches 32 and 34 handle only cars of unifonn height, although the safety latches do not prevent the dumper from handling cars of other heights.

The operator energizes the motor M and the dumper begins to rotate in the direction of the arrow 26. It will be noted that the clamp-lifting cable 110 tends to rotate the winding drum 62 clockwise due to the weight of the clamp beam 30. However, the drum-winding cable 98 prevents clockwise rotation because this forces the clamp-lifting carriage 100 downward, and the carriage abutment nose 106 rests on the stop member 108. Thus, as the winding drum 62 moves away from the stop member 108, the winding drum 62 is free to rotate clockwise. In this manner the clamp-lifting cable 110 pays off the winding drum and allows the clamp beam 30 to descend by gravity. At about 13 of rotation (the FIG. 5 position) the clamp beam 30 is resting upon the sidewalls of the railcar R. The latch 32 is still overbalanced onto its stop 128 and the latch 34 is, similarly, still overbalanced on its stop 132.

As soon as the bellcrank 86 is elevated far enough for its roller 88 to disengage the cam track (the 42 FIG. 6 position), the spring 92 pushes the link 84 upward and the shoe 78 releases the pawl lever 72. The spring 74 then pivots the lever 72 and moves the pawl 68 to engage the ratchet wheel 66. While the clamp-lifting cable 110 was being payed out, the clamp-holding cables 54 were being wound on the winding drum. Accordingly, as soon as the pawl 68 is engaged with the ratchet wheel 66, the winding drum cannot rotate counterclockwise without moving the counterweight 64. The clamp beam 30 is considered locked because it cannot move away from the railcar without moving the counterweight.

Rotation of the dumper beyond the FIG. 6 position tends to swing the counterweight 64 clockwise. This applies a torque to the winding drum to exert tension on the clamp-holding cables 54 in order to clamp the railcar R to the rails 24. The torque also provides an immediate follow up" action which resets the clamp beam if the clamp beam was initially set against an excess surcharge of material that is crushed or dislodged during the dumping operation. As rotation of the dumper progresses, the pressure applied to the clamp beam 30 increases, but the total pressure is limited to the weight of an average empty car in order to avoid crushing the sides of lighter than usual cars.

The brake 118 supplies additional emergency holding power in case part or all of the load does not dump, as may be the case if the contents are frozen. The brake is set automatically by the counterweight 116 at and beyond about of rotation of the dumper, and prevents reverse rotation of the winding drum if the total load resting on the clamp beams 30 exceeds the holding power of the counterweight 64. 1f the counterweights alone held the car and frozen contents, the same pressure would be applied to all cars, and this would be likely to damage light cars. Beyond the 90 rotated position of the dumper, the safety latches 32 and 34 swing away from their

stops

128 and 132, and begin to move toward their

respective abutment members

120 and 134.

The contents of the car are usually completely dumped by the time the dumper has rotated about 160 from its starting position. Neither

safety latch

32 or 34 is in an effective position at this rotative position of the car dumper. However, if the contents of the car do not dump, it is hazardous to rely solely on the clamp-holding cables 54.

Accordingly, as the dumper rotates beyond 160 gravity causes the

latches

32 and 34 to swing into operative positions where the

ledge portions

129 and 136, respectively, lie vertically aligned with the

abutments

120 and 134. As shown in FIG. 7, the ledges are slightly spaced from the abutments to assure free motion of the safety latches in moving to their operative positions. Thus positioned, the safety latches will now positively prevent the railcar from dropping if the clampholding cables 54 break, and in the event of such breakage will retain the beam clamps in position until the railcar is returned to a safe upright position because the frictional engagement of the

ledges

129 and 136 with the

abutments

120 and 134 will keep the latches in their locked positions.

It will be apparent that the gravity-operated mechanical safety latches 32 and 34 provide for positive retention of the beam clamps in the event the holding cables break, and provide a simpler and less costly alternative than using more beam clamps to increase the safety factor.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.

What is claimed is:

1. in a rotary car dumper including a railcar supporting cradle, a laterally extending overhead clamp arm and slidable means carrying said arm into closely adjacent overlying relation with a hopper type railcar to support the car when it is invetted by the dumper; the improvement comprising a first abutment mounted on said clamp arm, an adjacent first safety latch pivotally mounted in overbalanced condition on said cradle, a second abutment mounted on said cradle, and an ad jacent second safety latch pivotally mounted in overbalanced condition on said clamp am, said latches being gravitationally self-rotating when the dumper is inverted to move into blocking relation with their respective abutments and prevent any substantial downward displacement of the inverted clamp arm and the railcar supported by the clamp arm.

2. In a rotary car dumper including a railcar supporting cradle, a laterally extending overhead clamp arm and slidable means carrying said arm into closely adjacent overlying relation with the upper portions of an open top railcar to support the car when the dumper inverts the railcar, the improvement comprising a gravity-operated safety latch adjacent each end of said clamp arm, means pivotally connecting one of said latches to said cradle, means pivotally connecting the other of said latches to said clamp arm, abutment means mounted on said cradle adjacent the latch mounted on said clamp arm, and abutment means mounted on said clamp arm adjacent the latch mounted on said cradle, each latch being gravitally urged free of its associated abutment when the car dumper is upright to allow setting the clamp onto the railcar, and being swung by gravity into blocking relation with its associated abutment when the car dumper is inverted, said latches and abutments elevationally locking said clamp arm to prevent accidental release of the inverted railcar.

3. Apparatus according to claim 2 in which the clamp arm latch leads in the direction of inverting movement of the dumper and is generally L-shaped, a latch stop supporting the leading latch in an upright position overbalanced away from an upright car positioned in the dumper, said leading latch thus rotating in a clockwise direction about its associated pivot means when the dumper is inverted to swing the free end of the latch into underlying relation with its associated abutment means on said cradle.

4. Apparatus according to claim 3 in which the cradle latch trails in the direction of inverting movement of the dumper and extends inward from the clamp arm slide, a latch stop mounted on said clamp arm and supporting the trailing latch in a generally horizontal position with the car dumper upright so that the trailing latch rotates in a counterclockwise direction about its associated pivot means, and means defining an abutment ledge on said trailing latch, said ledge overlying said clamp arm abutment means when the dumper is inverted.

5. In a rotary car dumper including an invertible cradle and transverse beam clamp arms which are end-supported on fixed frame members and span and engage the cradle to support the inverted car while it is discharged, the improvement comprising a first pivot shaft secured to one end portion of said clamp arm, a freely pivotable first latch mounted on said first pivot shaft, a second pivot shaft mounted on said fixed frame members adjacent the other end of said clamp arm, a freely pivotable second latch mounted on said second pivot shaft, said first and second latches being respectively mounted on the trailing and leading portions of said clamp arm relative to the direction of inverting movement of said cradle, a first abutment mounted on said fixed frame member in the plane of swinging movement of said first latch, and a second abutment mounted on said clamp arm in the plane of swinging movement of said second latch, said first and second latches being gravity operated when the car dumper is inverted to position a portion of said second latch under its associated abutment and a portion of said first latch over its associated abutment to prevent downward movement of said clamp arm.

Claims

1. In a rotary car dumper incluDing a railcar supporting cradle, a laterally extending overhead clamp arm and slidable means carrying said arm into closely adjacent overlying relation with a hopper type railcar to support the car when it is inverted by the dumper; the improvement comprising a first abutment mounted on said clamp arm, an adjacent first safety latch pivotally mounted in overbalanced condition on said cradle, a second abutment mounted on said cradle, and an adjacent second safety latch pivotally mounted in overbalanced condition on said clamp arm, said latches being gravitationally self-rotating when the dumper is inverted to move into blocking relation with their respective abutments and prevent any substantial downward displacement of the inverted clamp arm and the railcar supported by the clamp arm.