Title:
RETRACTABLE RAILROAD CAR CLAMP
United States Patent 3777914
Abstract:
There is provided a clamping apparatus for clamping railroad cars into a rotary dumper capable of inverting cars to discharge the contents. The clamp is characterized in having a jaw member pivotally mounted on one end of an extensible arm. Stationary guide means are provided for coaction with the jaw to guide it along a predetermined path. Means are also provided coacting between the support and the jaw member for tilting the jaw member so that it clears the maximum composite envelope of locomotive profiles within the opening provided in the adjacent end ring of the rotary railroad car dumper.
US Patent References:
Rotary car dumper
Clark - January 1964 - 3116843
Rotary railroad car dumper car clamp latch
Sabin - February 1966 - 3232459
Rotary car dumper
Clark - January 1964 - 3116843
Rotary railroad car dumper car clamp latch
Sabin - February 1966 - 3232459
Inventors:
Cheek, Edward E. (Cleveland, OH)
Sabin, Raymond H. (Willoughby Hills, OH)
Sabin, Raymond H. (Willoughby Hills, OH)
Application Number:
05/241652
Publication Date:
12/11/1973
Filing Date:
04/06/1972
View Patent Images:
Export Citation:
Assignee:
McDowell-Wellman Engineering Company (Cleveland, OH)
Primary Class:
Other Classes:
414/360
International Classes:
B65G67/00; B65G67/54
Field of Search:
214/55,56
Primary Examiner:
Sheridan, Robert G.
Claims:
What is claimed is
1. A clamp apparatus for clamping a railroad car in a rotary railroad car dumper which includes a rotatable cradle, said apparatus comprising in combination:
2. A clamp apparatus in accordance with claim 1 in which the jaw member includes a laterally extending arm portion and an angularly related leg portion.
3. A clamp apparatus in accordance with claim 1 in which the extensible arm is pivotally attached to the cradle at its other extremity.
4. A clamp apparatus in accordance with claim 1 in which the extensible arm is a hydraulically actuated extensible arm.
5. A clamp apparatus in accordance with claim 1 in which the first cam follower means includes separate tilting roller means mounted on said jaw member and the second cam follower means includes pivot roller means.
6. A clamp apparatus in accordance with claim 5 in which the tilting roller means include vertically spaced roller means.
7. A clamp apparatus in accordance with claim 5 in which the roller means each include rollers mounted on pins extending from said jaw member and located at the apices of an obtuse triangle, the roller/pin assembly at the apex of the obtuse angle being disposed in the abutment-containing channel and the two remaining roller/pin assemblies being located in the remaining channel.
1. A clamp apparatus for clamping a railroad car in a rotary railroad car dumper which includes a rotatable cradle, said apparatus comprising in combination:
2. A clamp apparatus in accordance with claim 1 in which the jaw member includes a laterally extending arm portion and an angularly related leg portion.
3. A clamp apparatus in accordance with claim 1 in which the extensible arm is pivotally attached to the cradle at its other extremity.
4. A clamp apparatus in accordance with claim 1 in which the extensible arm is a hydraulically actuated extensible arm.
5. A clamp apparatus in accordance with claim 1 in which the first cam follower means includes separate tilting roller means mounted on said jaw member and the second cam follower means includes pivot roller means.
6. A clamp apparatus in accordance with claim 5 in which the tilting roller means include vertically spaced roller means.
7. A clamp apparatus in accordance with claim 5 in which the roller means each include rollers mounted on pins extending from said jaw member and located at the apices of an obtuse triangle, the roller/pin assembly at the apex of the obtuse angle being disposed in the abutment-containing channel and the two remaining roller/pin assemblies being located in the remaining channel.
Description:
BACKGROUND OF THE INVENTION AND PRIOR ART
This invention relates as indicated to a clamping apparatus especially adapted for use in a rotary railroad car dumper. The design and construction of a rotary railroad car dumper includes consideration not readily apparent. For example, the diameter of the cradle which receives the railroad car or cars for inverting such car or cars while in a coupled condition is not a matter of capricious choice. If the diameter of the cradle is larger than need be, then the foundation for supporting the rotary railraod car dumper must be larger and hence more expensive. Accordingly, it is desired to build the cradle with as small a diameter as possible. On the other hand, the end rings which define the cradle and provide the gears by which the cradle is revolved about its axis must be constructed so as to have sufficient strength to support one or more railroad cars. Also, the structure must withstand the loads imposed by the passage of a locomotive through the cradle if such may be a means for introducing railroad cars into the cradle. Another factor which influences the structure of the cradle is that it must be able to accommodate railroad cars of different height as well as different width. Allowances for these profile variations may influence the cradle structure and the diameter of the apparatus. Still further, the cross-sectional profile of the locomotive or locomotives which must be accommodated by the device affects the diameter and the strength requirements of the end rings.
Because of the previously mentioned variation in the width of the railroad cars which may be handled by the device, it has become a practice in the trade to provide a severed track portion within the confines of the cradle which is movable laterally toward one side of the cradle. To the accomplishment of this end, the tracks are supported upon a platform or carriage which is in turn supported on rollers. By suitable means, the cars may be moved toward one side of the cradle. In such case, the car clamping apparatus on the side toward which the cars are moved may have a jaw member of fixed short dimension since the sidewall of the railroad cars against which it clamps will normally be laterally moved to abut against a fixed abutment member carried by the cradle. The clamps with the short inwardly projecting jaw portion on this particular side of the cradle may then be lowered to engage the marginal edge of the car or cars and thereby hold the car tightly against the track portion.
On the opposite side of the cradle, clamps are also provided; but, because of the extent to which the cars may move laterally toward the opposite side of the cradle and the variations in car width, the inwardly projecting jaw portion must be of substantially longer length so as to be able to engage the upper marginal edge of the railroad car. If, for example, the lateral travel of the platform and the railroad car carried thereon is 7 1/2 inches and the variation in the width of the cars is as much as 4 to 5 inches, the jaw member on the side opposite the side against which the cars normally rest during inversion must be up to a foot longer than the jaw members on the opposite side in order to be able to engage the upper marginal edges of the sidewalls of the railroad cars. The clamps on the opposite sides of the railroad cars, then, serve to hold the car and the platform in position in the cradle during inversion to empty the contents of the car.
Bearing in mind the desirability for minimum diameter of the cradle, the need to rotate cars about the draft gear axis so they can remain coupled during the dumping operation and the variety of profiles of locomotives which may pass through the cradle, and the longer projection of the jaw member on one side, the need for sufficient head room to enable clearance of the longer jaw member by the locomotives becomes apparent.
The present invention solves this problem in a unique manner. It would be a relatively simple matter to increase the diameter of the cradle to allow for passage of locomotives of various heights, widths, and the like. But, this encounters the problem of rotation of coupled railroad cars as well as the foundation requirements for larger diameter structures. The present invention, therefore, is in the provision of means for tilting the longer jaw member about an axis which is parallel to the axis of the rotation of the dumper to raise the inner extremity of the elongated jaw body so that the maximum composite profile of all locomotives which might pass through the rotary car dumper is accommodated while maintaining the diameter of the apparatus at a minimum and without sacrificing the required strength of the end rings for supporting the loads to be encountered.
The prior art has solved this problem by such expediences as increased diameters, by spacing the clamps a distance away from the end rings so that they may extend above the structure of the cradle and by providing slit clamps operative on both sides of an end ring and able to accommodate the end ring structure between axially spaced jaw portions. None of the prior art presently known to me contemplates structure for tilting the jaw out of the envelope of the maximum composite profile of locomotives but within the envelope of a minimum diameter cradle.
Many retractable clamps have been made, but all have been used in applications where all cars are of the same height, requiring only short cylinder stroke to retract for locomotive clearance.
When random height car operation is required, the prior art requires an extremely long clamp stroke for locomotive clearance, thereby preventing clamps from being located at the end rings or high hydraulic pump volume capacity if not at the end ring.
This invention combines the advantages of the retractable clamp for locomotive clearance with random height car operation, thereby limiting the cylinder stroke to only what is required for minimum and maximum car height plus a small amount for retraction. These clamps can also be used to advantage on dumpers with clamps located away from the end rings where random height cars and large locomotives pass through for holding pump volume capacity to a minimum. There is further advantage in reduction of the length of guides and cylinders.
The annexed drawing shows retractable clamps on rear side only. It should be understood that retractable clamps may be required on dump side also for some applications.
BRIEF STATEMENT OF THE INVENTION
Briefly stated, the present invention is in a clamp apparatus for use in a rotary railroad car dumper which includes a rotatable cradle. The apparatus comprises in combination a jaw member, an extensible arm pivotally connected on an axis at one of its extremities to the jaw member, means for attaching the other extremity of the arm to the cradle body, and means for extending and retracting the extensible arm to move the jaw member along a predetermined path. Stationary guide means mountable on the cradle are provided which coact with the jaw member for guiding the jaw member along a first path. Means are provided which coact between the guide means and the jaw member for tilting the jaw member along a second path joining said first path and lying in a plane normal to the pivot axis between the extensible arm and the jaw member. Thus, when the jaw member is moved by the extensible arm upwardly toward an opened position along the first path, it then encounters the second path and is tilted out of the way so that the laterally extending portion of the jaw member will be removed from a position which would otherwise interfere with the passage of vehicles through a rotatable cradle. When the extensible arm is retracted toward a clamping position, the jaw member is tilted back toward a clamping position along the second path and enters then the first path wherein clamping may be effected by further retraction of the extensible arm until the laterally projecting portion of the jaw comes into abutting relation with the top marginal edge of a railroad car.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be better understood by having reference to the annexed drawings wherein:
FIG. 1 is a partial plan view of a section through a cradle looking toward one of the end rings and showing a pair of oppositely disposed railroad car clamps, the left-hand clamp assembly embodying the present invention.
FIG. 2 is a cross-sectional view through the clamp apparatus shown in FIG. 1 as it appears in the plane indicated by the line 2--2 in FIG. 1.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now more particularly to the annexed drawings, FIG. 1 shows a view of a typical rotary car dumper end ring. The structure of the end ring may be conventional and is not important to the present invention other than in determining the space limits within which the car holding clamps must operate. Accordingly, the details of construction of the end ring or the rotatable cradle will not be described.
There is thus partially shown in FIG. 1 end ring structure 10. In dotted line there is shown a maximum composite profile 12 representing the maximum projections of known locomotives which may have occasion to move through end ring 10. The opening 14 in end ring 10 is defined by the marginal edges 16, 18, 20, 22, and 24, these edges being located so that both the opening 14 and the hoop strength of the end ring are of sufficient design to withstand the loads to be imposed thereon. Determination of these parameters is known to those skilled in the art. For structural reasons, it is desirable to locate the railroad car holding clamps close to or in the plane of the end rings, two such end rings being provided for each rotary car dumper cradle. It is when this desire is accommodated that problems are encountered with the necessary length of travel of the clamping jaws to provide adequate clearance for locomotives of a variety of profiles at minimum end ring diameter.
The opening 14 is further defined by the bottom marginal edge 26, lateral risers 28 and 30, and platforms 32 and 34. Also shown in cross-section is a shiftable carriage 36 on which are mounted rails 38 and 40 for supporting railroad cars and locomotives. The structure of the carriage 36 may also be conventional and forms no part of the present invention. Although it does not appear in FIG. 1, the platforms 32 and 34 are of sufficient width to serve as mounting surfaces for the clamp assemblies. In normal operation the carriage 36 is conventionally mounted on rollers or wheels and is laterally shiftable toward the right-hand side of the cradle as shown in FIG. 1 in dotted lines. This shift brings the upper marginal edge of the sidewall of any railroad car of the gondola type, for example, against an abutment 42. The clamping apparatus on the right-hand side of the dumper as shown in FIG. 1, therefore, has a design of only limited variability because the sidewall of a railroad car by operation of the shiftable carriage 36 will be brought into abutting relation with abutment 42 and the jaw member 44 will open closure thereof invariably engage and hold the top marginal edge of the railroad car. Accordingly, the hydraulically actuated clamp assembly generally indicated at 46 for one side of the railroad cars may be of the standard or conventional design shown. Usually two such right-hand clamps at spaced intervals, e.g. at the end rings, are provided for a single car rotary dumper. Where the rotary dumper is adapted to accommodate two cars, there may be four such right-hand sidewall clamps. Thus, the clamp assembly 46 includes an extensible arm assembly 48 having a hydraulic cylinder 50 pivotally secured at its lower extremity to a mounting structure 52 which is in turn secured to the platform 34. The extensible arm 54 is also pivotally secured to the clamp actuator 56 which moves along a predetermined path determined by the guide rails, e.g. rail 58. The limits of travel of the jaw 44 are shown in dotted lines. Since the inward projection of the jaw 44 is outside the maximum composite profile 12, no interference with passage of locomotives from such clamps is experienced.
The clamping assembly on the opposite (left) side of the cradle includes the subject matter of the present invention. Because of the range of movement of the carriage 36 and the variation in the widths of railroad cars, the jaw member 60 includes a laterally projecting portion 62 of considerably greater length than that of the jaw 44. As can be seen, if the apparatus were not provided with some means for displacing the jaw 60 and its upper limit of travel were limited by marginal edge 18, the distal extremity of laterally projecting portion 62 would intercept the maximum composite locomotive profile 12 and prevent passage of at least some locomotives.
The clamping assembly of the present invention provides, therefore, means for tilting the jaw 60 so as to occupy a position within the envelope described by the marginal edges 16 and 18 but so that the inward extremity of laterally projecting portion 62 is outside the maximum composite profile 12.
To the accomplishment of this end there is provided a clamping assembly having a jaw 60 including the laterally projecting portion 62 and a depending leg portion 64. The lower extremity of the leg portion 64 is pivotally connected to the outer extremity of piston rod 66 which may be extended from or retracted into cylinder 68 by hydraulic means in a known manner. The axis of the pivot 70 is parallel to the axis of rotation of the dumper indicated at 72. The lower extremity of the cylinder 68 is in turn pivotally secured as by pivot 74 coacting between flange 76 and mounting flange 78 in turn secured to mounting block 80. Any suitable means of securing the mounting block 80 to the platform 32 may be employed, this particular structure forming no part of the present invention.
There is provided a special guide member generally indicated at 82 which guide member defines for a portion of the stroke of the piston rod 66 a first path of generally vertical disposition. The first path communicates with a second tilting path as will be hereinafter more particularly explained.
As better shown in FIG. 2, the guide structure 82 may be formed of a pair of channels 84 and 86 disposed parallel to each other and in combination with plates 88 and 90 defining a box-like structure in which the jaw member 60 may be moved. A slot 92 is provided for vertical passage of the jaw 60. Within the box-like structure above described there are provided a pair of opposed rails 94 and 96 secured to the channels 84 and 86, respectively, and defining therebetween by virtue of their spaced relation an opening 98 of sufficient dimension to allow passage of the jaw 60 therebetween. The rails 94 and 96 in combination with the plate 88 define a slot 100 in which pivot rollers 102 and 104 may move vertically. Likewise, rails 94 and 96 define in combination with plate 90 a slot 106 in which tilting rollers 108 and 110 may move vertically. The rollers 102 and 104 are mounted on an axle 112 which is in turn carried by the lower extremity of depending leg portion 64.
As best shown in FIG. 1, the slot 100 is provided with a stop 114 against which the pivot rollers 102 and 104 abut at the end of the first path of travel of the jaw 60 before it enters the tilting or second portion of the path of travel. The slot 106 has no such abutment. As shown in FIG. 1, the forward or right-hand edge of the leg portion 64 is provided with two sets of rollers, one set including tilting rollers 108 and 110, and the second set including roller 116 and a corresponding roller on the same axle (not shown). Also within the body of the guide 82 there is provided a cam surface 118 along which tilting rollers 108 and 110 follow after rollers 102 and 104 have been arrested in vertical movement by the abutment or stop 114. The cam surface 118 in cooperation with the cam following tilting rollers 108 and 110 define the second tilting path portion. The second pair of rollers including roller 116 contact and roll against the plate 90 which is duly spaced from the rails 94 and 96 a distance greater than the diameter of the set of rollers including roller 116. Since the leg portion 64 has a width and will be undergoing a tilting action, the set of rollers including roller 116 will be displaced in the manner shown in FIG. 1 so as to come into abutting rolling relationship with the plate 90. This action limits the extent of tilt.
Thus, the contour of the second path portion in which tilting of the jaw 60 is accomplished is determined by the location of the abutment 114, the width of the slot 106 in the plate of tilting, and the contour of the cam 118. When the extensible arm 66 is retracted, the set of tilting rollers 108 and 110 traverse the upper contour of the cam member 118, and enter the slot 106. When both sets of rollers on the innermost edge of the depending leg portion 64 are within the slot 106, retrograde motion of the outer end or distal extremity of jaw 60 is prevented. The uppermost set of tilting rollers 108 and 110 will bear against the vertical portion of the cam surface 118, and the lower set of rollers including rollers 102 and 104 will bear against rails 94 and 96. The length of the channel 106, then, is sufficient to accommodate a variety of heights of railroad cars and may have, for example, a length sufficient to accommodate a stroke of the extensible arm of as much as 49 to 50 inches or more.
It should be pointed out that the axis of the sets of rollers in the preferred embodiment are located at the apices of an obtuse triangle. Thus, if we consider the axle 120 on which the set of tilting rollers 108 and 110 are mounted as point A, the axle 112 of the set of pivot rollers 102 and 104 as point B, and the axle 122 adjacent the lower marginal edge of the leg portion 64 on which the set of rollers including roller 116 rotate as point C, the angle ABC is obtuse and ranges from about 95° to 105°.
The laterally extending portion 62 of the jaw 60 is provided along its lower marginal edge with a flange plate 124 for distribution of the forces of clamping over a larger area consistent with good clamp design. In like manner a flange plate 126 is provided on the jaw member 44.
There has thus been provided a clamping apparatus including an extensible arm, preferably hydraulically actuated, for use in a rotary railroad car dumper on at least one side of the cradle. While the clamping assemblies of the present invention may be used on both sides of the cradle if desired, better practice contemplates the provision of a laterally displaceable carriage for the railroad cars being dumped whereby they are displaced into abutting relationship with one side of the cradle. Thus the length of the jaws of the clamping apparatus on the abutment side of the cradle may be of relatively short width. In operation, then, before dumping, the cars are laterally displaced to one side a relatively short distance and the clamps lowered into clamping relationship with the upper marginal edges of the railroad cars. A set of four clamps is employed for each railroad car, two on each side. These clamps are secured at their lower extremities to the cradle and serve to hold the car in the cradle during rotation thereof in a known manner. However, when a locomotive must pass through the dumper, the clamps on each side must be raised to the maximum stroke so that the envelope occupied by the locomotive may be cleared. The present invention provides a means for tilting the jaw member having the elongated laterally projecting portion out of the locomotive envelope, thereby removing any obstruction to its passage through the cradle. The tilting action is achieved by novel cam and cam follower means coacting between the jaw and the guide means therefor.
This invention relates as indicated to a clamping apparatus especially adapted for use in a rotary railroad car dumper. The design and construction of a rotary railroad car dumper includes consideration not readily apparent. For example, the diameter of the cradle which receives the railroad car or cars for inverting such car or cars while in a coupled condition is not a matter of capricious choice. If the diameter of the cradle is larger than need be, then the foundation for supporting the rotary railraod car dumper must be larger and hence more expensive. Accordingly, it is desired to build the cradle with as small a diameter as possible. On the other hand, the end rings which define the cradle and provide the gears by which the cradle is revolved about its axis must be constructed so as to have sufficient strength to support one or more railroad cars. Also, the structure must withstand the loads imposed by the passage of a locomotive through the cradle if such may be a means for introducing railroad cars into the cradle. Another factor which influences the structure of the cradle is that it must be able to accommodate railroad cars of different height as well as different width. Allowances for these profile variations may influence the cradle structure and the diameter of the apparatus. Still further, the cross-sectional profile of the locomotive or locomotives which must be accommodated by the device affects the diameter and the strength requirements of the end rings.
Because of the previously mentioned variation in the width of the railroad cars which may be handled by the device, it has become a practice in the trade to provide a severed track portion within the confines of the cradle which is movable laterally toward one side of the cradle. To the accomplishment of this end, the tracks are supported upon a platform or carriage which is in turn supported on rollers. By suitable means, the cars may be moved toward one side of the cradle. In such case, the car clamping apparatus on the side toward which the cars are moved may have a jaw member of fixed short dimension since the sidewall of the railroad cars against which it clamps will normally be laterally moved to abut against a fixed abutment member carried by the cradle. The clamps with the short inwardly projecting jaw portion on this particular side of the cradle may then be lowered to engage the marginal edge of the car or cars and thereby hold the car tightly against the track portion.
On the opposite side of the cradle, clamps are also provided; but, because of the extent to which the cars may move laterally toward the opposite side of the cradle and the variations in car width, the inwardly projecting jaw portion must be of substantially longer length so as to be able to engage the upper marginal edge of the railroad car. If, for example, the lateral travel of the platform and the railroad car carried thereon is 7 1/2 inches and the variation in the width of the cars is as much as 4 to 5 inches, the jaw member on the side opposite the side against which the cars normally rest during inversion must be up to a foot longer than the jaw members on the opposite side in order to be able to engage the upper marginal edges of the sidewalls of the railroad cars. The clamps on the opposite sides of the railroad cars, then, serve to hold the car and the platform in position in the cradle during inversion to empty the contents of the car.
Bearing in mind the desirability for minimum diameter of the cradle, the need to rotate cars about the draft gear axis so they can remain coupled during the dumping operation and the variety of profiles of locomotives which may pass through the cradle, and the longer projection of the jaw member on one side, the need for sufficient head room to enable clearance of the longer jaw member by the locomotives becomes apparent.
The present invention solves this problem in a unique manner. It would be a relatively simple matter to increase the diameter of the cradle to allow for passage of locomotives of various heights, widths, and the like. But, this encounters the problem of rotation of coupled railroad cars as well as the foundation requirements for larger diameter structures. The present invention, therefore, is in the provision of means for tilting the longer jaw member about an axis which is parallel to the axis of the rotation of the dumper to raise the inner extremity of the elongated jaw body so that the maximum composite profile of all locomotives which might pass through the rotary car dumper is accommodated while maintaining the diameter of the apparatus at a minimum and without sacrificing the required strength of the end rings for supporting the loads to be encountered.
The prior art has solved this problem by such expediences as increased diameters, by spacing the clamps a distance away from the end rings so that they may extend above the structure of the cradle and by providing slit clamps operative on both sides of an end ring and able to accommodate the end ring structure between axially spaced jaw portions. None of the prior art presently known to me contemplates structure for tilting the jaw out of the envelope of the maximum composite profile of locomotives but within the envelope of a minimum diameter cradle.
Many retractable clamps have been made, but all have been used in applications where all cars are of the same height, requiring only short cylinder stroke to retract for locomotive clearance.
When random height car operation is required, the prior art requires an extremely long clamp stroke for locomotive clearance, thereby preventing clamps from being located at the end rings or high hydraulic pump volume capacity if not at the end ring.
This invention combines the advantages of the retractable clamp for locomotive clearance with random height car operation, thereby limiting the cylinder stroke to only what is required for minimum and maximum car height plus a small amount for retraction. These clamps can also be used to advantage on dumpers with clamps located away from the end rings where random height cars and large locomotives pass through for holding pump volume capacity to a minimum. There is further advantage in reduction of the length of guides and cylinders.
The annexed drawing shows retractable clamps on rear side only. It should be understood that retractable clamps may be required on dump side also for some applications.
BRIEF STATEMENT OF THE INVENTION
Briefly stated, the present invention is in a clamp apparatus for use in a rotary railroad car dumper which includes a rotatable cradle. The apparatus comprises in combination a jaw member, an extensible arm pivotally connected on an axis at one of its extremities to the jaw member, means for attaching the other extremity of the arm to the cradle body, and means for extending and retracting the extensible arm to move the jaw member along a predetermined path. Stationary guide means mountable on the cradle are provided which coact with the jaw member for guiding the jaw member along a first path. Means are provided which coact between the guide means and the jaw member for tilting the jaw member along a second path joining said first path and lying in a plane normal to the pivot axis between the extensible arm and the jaw member. Thus, when the jaw member is moved by the extensible arm upwardly toward an opened position along the first path, it then encounters the second path and is tilted out of the way so that the laterally extending portion of the jaw member will be removed from a position which would otherwise interfere with the passage of vehicles through a rotatable cradle. When the extensible arm is retracted toward a clamping position, the jaw member is tilted back toward a clamping position along the second path and enters then the first path wherein clamping may be effected by further retraction of the extensible arm until the laterally projecting portion of the jaw comes into abutting relation with the top marginal edge of a railroad car.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be better understood by having reference to the annexed drawings wherein:
FIG. 1 is a partial plan view of a section through a cradle looking toward one of the end rings and showing a pair of oppositely disposed railroad car clamps, the left-hand clamp assembly embodying the present invention.
FIG. 2 is a cross-sectional view through the clamp apparatus shown in FIG. 1 as it appears in the plane indicated by the line 2--2 in FIG. 1.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now more particularly to the annexed drawings, FIG. 1 shows a view of a typical rotary car dumper end ring. The structure of the end ring may be conventional and is not important to the present invention other than in determining the space limits within which the car holding clamps must operate. Accordingly, the details of construction of the end ring or the rotatable cradle will not be described.
There is thus partially shown in FIG. 1 end ring structure 10. In dotted line there is shown a maximum composite profile 12 representing the maximum projections of known locomotives which may have occasion to move through end ring 10. The opening 14 in end ring 10 is defined by the marginal edges 16, 18, 20, 22, and 24, these edges being located so that both the opening 14 and the hoop strength of the end ring are of sufficient design to withstand the loads to be imposed thereon. Determination of these parameters is known to those skilled in the art. For structural reasons, it is desirable to locate the railroad car holding clamps close to or in the plane of the end rings, two such end rings being provided for each rotary car dumper cradle. It is when this desire is accommodated that problems are encountered with the necessary length of travel of the clamping jaws to provide adequate clearance for locomotives of a variety of profiles at minimum end ring diameter.
The opening 14 is further defined by the bottom marginal edge 26, lateral risers 28 and 30, and platforms 32 and 34. Also shown in cross-section is a shiftable carriage 36 on which are mounted rails 38 and 40 for supporting railroad cars and locomotives. The structure of the carriage 36 may also be conventional and forms no part of the present invention. Although it does not appear in FIG. 1, the platforms 32 and 34 are of sufficient width to serve as mounting surfaces for the clamp assemblies. In normal operation the carriage 36 is conventionally mounted on rollers or wheels and is laterally shiftable toward the right-hand side of the cradle as shown in FIG. 1 in dotted lines. This shift brings the upper marginal edge of the sidewall of any railroad car of the gondola type, for example, against an abutment 42. The clamping apparatus on the right-hand side of the dumper as shown in FIG. 1, therefore, has a design of only limited variability because the sidewall of a railroad car by operation of the shiftable carriage 36 will be brought into abutting relation with abutment 42 and the jaw member 44 will open closure thereof invariably engage and hold the top marginal edge of the railroad car. Accordingly, the hydraulically actuated clamp assembly generally indicated at 46 for one side of the railroad cars may be of the standard or conventional design shown. Usually two such right-hand clamps at spaced intervals, e.g. at the end rings, are provided for a single car rotary dumper. Where the rotary dumper is adapted to accommodate two cars, there may be four such right-hand sidewall clamps. Thus, the clamp assembly 46 includes an extensible arm assembly 48 having a hydraulic cylinder 50 pivotally secured at its lower extremity to a mounting structure 52 which is in turn secured to the platform 34. The extensible arm 54 is also pivotally secured to the clamp actuator 56 which moves along a predetermined path determined by the guide rails, e.g. rail 58. The limits of travel of the jaw 44 are shown in dotted lines. Since the inward projection of the jaw 44 is outside the maximum composite profile 12, no interference with passage of locomotives from such clamps is experienced.
The clamping assembly on the opposite (left) side of the cradle includes the subject matter of the present invention. Because of the range of movement of the carriage 36 and the variation in the widths of railroad cars, the jaw member 60 includes a laterally projecting portion 62 of considerably greater length than that of the jaw 44. As can be seen, if the apparatus were not provided with some means for displacing the jaw 60 and its upper limit of travel were limited by marginal edge 18, the distal extremity of laterally projecting portion 62 would intercept the maximum composite locomotive profile 12 and prevent passage of at least some locomotives.
The clamping assembly of the present invention provides, therefore, means for tilting the jaw 60 so as to occupy a position within the envelope described by the marginal edges 16 and 18 but so that the inward extremity of laterally projecting portion 62 is outside the maximum composite profile 12.
To the accomplishment of this end there is provided a clamping assembly having a jaw 60 including the laterally projecting portion 62 and a depending leg portion 64. The lower extremity of the leg portion 64 is pivotally connected to the outer extremity of piston rod 66 which may be extended from or retracted into cylinder 68 by hydraulic means in a known manner. The axis of the pivot 70 is parallel to the axis of rotation of the dumper indicated at 72. The lower extremity of the cylinder 68 is in turn pivotally secured as by pivot 74 coacting between flange 76 and mounting flange 78 in turn secured to mounting block 80. Any suitable means of securing the mounting block 80 to the platform 32 may be employed, this particular structure forming no part of the present invention.
There is provided a special guide member generally indicated at 82 which guide member defines for a portion of the stroke of the piston rod 66 a first path of generally vertical disposition. The first path communicates with a second tilting path as will be hereinafter more particularly explained.
As better shown in FIG. 2, the guide structure 82 may be formed of a pair of channels 84 and 86 disposed parallel to each other and in combination with plates 88 and 90 defining a box-like structure in which the jaw member 60 may be moved. A slot 92 is provided for vertical passage of the jaw 60. Within the box-like structure above described there are provided a pair of opposed rails 94 and 96 secured to the channels 84 and 86, respectively, and defining therebetween by virtue of their spaced relation an opening 98 of sufficient dimension to allow passage of the jaw 60 therebetween. The rails 94 and 96 in combination with the plate 88 define a slot 100 in which pivot rollers 102 and 104 may move vertically. Likewise, rails 94 and 96 define in combination with plate 90 a slot 106 in which tilting rollers 108 and 110 may move vertically. The rollers 102 and 104 are mounted on an axle 112 which is in turn carried by the lower extremity of depending leg portion 64.
As best shown in FIG. 1, the slot 100 is provided with a stop 114 against which the pivot rollers 102 and 104 abut at the end of the first path of travel of the jaw 60 before it enters the tilting or second portion of the path of travel. The slot 106 has no such abutment. As shown in FIG. 1, the forward or right-hand edge of the leg portion 64 is provided with two sets of rollers, one set including tilting rollers 108 and 110, and the second set including roller 116 and a corresponding roller on the same axle (not shown). Also within the body of the guide 82 there is provided a cam surface 118 along which tilting rollers 108 and 110 follow after rollers 102 and 104 have been arrested in vertical movement by the abutment or stop 114. The cam surface 118 in cooperation with the cam following tilting rollers 108 and 110 define the second tilting path portion. The second pair of rollers including roller 116 contact and roll against the plate 90 which is duly spaced from the rails 94 and 96 a distance greater than the diameter of the set of rollers including roller 116. Since the leg portion 64 has a width and will be undergoing a tilting action, the set of rollers including roller 116 will be displaced in the manner shown in FIG. 1 so as to come into abutting rolling relationship with the plate 90. This action limits the extent of tilt.
Thus, the contour of the second path portion in which tilting of the jaw 60 is accomplished is determined by the location of the abutment 114, the width of the slot 106 in the plate of tilting, and the contour of the cam 118. When the extensible arm 66 is retracted, the set of tilting rollers 108 and 110 traverse the upper contour of the cam member 118, and enter the slot 106. When both sets of rollers on the innermost edge of the depending leg portion 64 are within the slot 106, retrograde motion of the outer end or distal extremity of jaw 60 is prevented. The uppermost set of tilting rollers 108 and 110 will bear against the vertical portion of the cam surface 118, and the lower set of rollers including rollers 102 and 104 will bear against rails 94 and 96. The length of the channel 106, then, is sufficient to accommodate a variety of heights of railroad cars and may have, for example, a length sufficient to accommodate a stroke of the extensible arm of as much as 49 to 50 inches or more.
It should be pointed out that the axis of the sets of rollers in the preferred embodiment are located at the apices of an obtuse triangle. Thus, if we consider the axle 120 on which the set of tilting rollers 108 and 110 are mounted as point A, the axle 112 of the set of pivot rollers 102 and 104 as point B, and the axle 122 adjacent the lower marginal edge of the leg portion 64 on which the set of rollers including roller 116 rotate as point C, the angle ABC is obtuse and ranges from about 95° to 105°.
The laterally extending portion 62 of the jaw 60 is provided along its lower marginal edge with a flange plate 124 for distribution of the forces of clamping over a larger area consistent with good clamp design. In like manner a flange plate 126 is provided on the jaw member 44.
There has thus been provided a clamping apparatus including an extensible arm, preferably hydraulically actuated, for use in a rotary railroad car dumper on at least one side of the cradle. While the clamping assemblies of the present invention may be used on both sides of the cradle if desired, better practice contemplates the provision of a laterally displaceable carriage for the railroad cars being dumped whereby they are displaced into abutting relationship with one side of the cradle. Thus the length of the jaws of the clamping apparatus on the abutment side of the cradle may be of relatively short width. In operation, then, before dumping, the cars are laterally displaced to one side a relatively short distance and the clamps lowered into clamping relationship with the upper marginal edges of the railroad cars. A set of four clamps is employed for each railroad car, two on each side. These clamps are secured at their lower extremities to the cradle and serve to hold the car in the cradle during rotation thereof in a known manner. However, when a locomotive must pass through the dumper, the clamps on each side must be raised to the maximum stroke so that the envelope occupied by the locomotive may be cleared. The present invention provides a means for tilting the jaw member having the elongated laterally projecting portion out of the locomotive envelope, thereby removing any obstruction to its passage through the cradle. The tilting action is achieved by novel cam and cam follower means coacting between the jaw and the guide means therefor.