Background of the Invention
This invention relates to a retractable and distensible railroad wheel assembly for attachment to a road vehicle that enables the road vehicle to travel along a railroad track.
In the past, various self-propelled vehicles have been developed which can travel over a normal flat road surface and which also travel on railroad tracks. Usually, the prior art vehicles have been vehicles that have been modified to include railroad wheels that can be attached to the vehicle for railroad track travel. In some instances, retractable and distensible railroad wheel assemblies have been combined with road vehicles which enable the road vehicles to be converted from a road vehicle to a rail-mounted vehicle when the vehicle is to move from the road surface to the railroad track. The road driving wheels of some of the prior art vehicles also engage the track and propel the vehicle along the track and the vehicles can be used for various load carrying jobs and maintenance jobs on a railroad track.
Summary of the Invention
Briefly described, the present invention comprises a retractable and distensible railroad wheel assembly for road vehicles which is of relatively lightweight construction and yet is fast-acting, reliable and provides enough stability for the vehicle on the railroad tracks to enable the vehicle to carry heavy loads and to dump loads to the side of the railroad track and still allow the road wheels to bear part of the load and to propel the vehicle along the track. The retractable and distensible roalroad wheel assembly comprises a pair of support bearings mounted on each side of the vehicle, an axle extending across the normal direction of movement of the vehicle, railroad wheels mounted on the ends of the axle, and a linkage assembly connected between each pair of support bearings at the sides of the vehicle and the axle. The linkage assemblies each include a wheel support arm pivotally connected at one of its ends to one of the support bearings and an actuating linkage connected between the other support bearing and the axle and which is foldable and unfoldable to move the axle and wheels through an arc to distend and retract the wheels beneath the vehicle. A fluid actuated ram is connected to one of the links in the actuating linkage and its ramrod is connected to the other link in the actuating linkage so that the retraction and distension of the ram folds and unfolds the linkage assembly, and the ram and actuating linkage are constructed to have their greatest downward effective force just as the wheels of the railroad wheel assembly engage the rails of the track and as the support arm and linkage assembly begin to support and stabilize the vehicle on the rails.
Thus, it is an object of this invention to provide a retractable and distensible railroad wheel assembly for road vehicles, such as for rotatable dumps and other load-carrying vehicles, which is fast-acting, reliable, and which provides a stable support for the vehicle on railroad tracks.
Another object of this invention is to provide a retractable and distensible railroad wheel assembly for self-propelled road vehicles which is reliable and inexpensive, which is retractable to a compact position where it is out of the way of the normal work functions of the vehicle, and which can be mounted on the front and on the rear of the vehicle.
Other objects, features and advantages of the present invention will become apparent upon reading the following specification, when taken in conjunction with the accomanying drawing.
Brief Description of the Drawing
FIG. 1 is a rear view of a rotary dump vehicle and illustrates the retractable and distensible railroad wheel assembly mounted on the vehicle, showing the vehicle mounted on a railroad track with its dump body rotated and tilted.
FIG. 2 is a side elevational view of the retractable and distensible railroad wheel assembly, illustrating one railroad wheel, the axle, one pair of support bearings, the wheel support arm and the actuating linkage and fluid actuated ram, with the wheel assembly shown in its downwardly distended position.
FIG. 3 is a side elevational view of the railroad wheel assembly, similar to FIG. 2, but showing the wheel assembly in its upward retracted position.
FIG. 4 is a rear view of the actuating linkage assembly.
Detailed Description
Referring now in more detail to the drawing, in which like numerals indicate like parts throughout the several views, FIG. 1 illustrates a rotary dump load-carrying vehicle 10 which includes a vehicle framework 11, ground-engaging wheels 12 mounted on the framework, a passenger cab 14 and a rotatable and tiltable dump body 15. The vehicle 10 is illustrated as being mounted on and driven on a railroad track 16 which includes a ballast 18, crossties 19 and rails 20. A pair of railroad wheels 21 and 22 are located at the rear of the vehicle 10 and partially support and stabilize the vehicle from the railroad track 16, while the inner road-engaging wheels 12a and 12b also engage the rails 20 and function to partially support and to move the vehicle 10 along the length of the railroad track. An additional pair of railroad wheels (not shown in FIG. 1) are mounted on the vehicle frame 11 at the front portion of the vehicle ahead of the front steerable road wheels of the vehicle (not shown) and support and guide the front portion of the vehicle along the railroad track. The front and rear pair of railroad wheels are each mounted on a common axle, such as axle 24 of the rear pairs of wheels 21 and 22.
As illustrated in FIG. 2, the railroad wheel assembly 23 includes pairs of support bearings 25 and 26 connected to the undersurface of the framework 11 of the vehicle at opposite sides of the vehicle at the rear of the vehicle, and at opposite sides of the vehicle at the front of the vehicle (not shown). Support bearing 25 is a clevis assembly that comprises a bracket 28 and a pair of plates 29 and 30 (FIG. 4) extending from the open end of the bracket. Plates 29 and 30 define aligned openings therein and pivot pin 31 extends through the aligned openings. The support bearing 26 is similar to bearing 25 in that it is a clevis assembly that comprises a bracket 32 mounted on the lower surface of the framework 11 and a pair of spaced parallel plates 34 (only one shown) defining aligned openings through which pivot pin 35 extends. Bearing sleeves 31a and 35a surround the pivot pins 31 and 35, respectively.
Wheel support arm 36 is connected at one of its ends to support bearing 26 and at its other end to axle bearing 38 (FIG. 4) which surrounds the axle 24. Actuating linkage 39 comprises a pair of duplicate actuating plates 40 and 41 that function as actuating link means, and intermediate link plates 42 and 43 which function as intermediate link means. Actuating link plates 40 and 41 are approximately triangular in shape and define aligned openings for the receipt of pivot pin 31 of support bearing 25, mounting pin 45 and pivot pin 46. The pins 31, 45 and 46 are arranged in triangular relationship with respect to one another. Intermediate link plates 42 and 43 each define aligned openings for the receipt of pivot pin 46, and each link plate is rigidly connected to an axle bearing 47 and 48. Bearing sleeves 45a and 46a surround mounting pin 45 and pivot pin 46, and the intermediate link plates 42 and 43 are connected to the bearing sleeve 46a.
Fluid-actuated ram 49 comprises a cylinder 50 rigidly connected to the sleeve 45a of mounting pin 45 and a ramrod which is distensible and retractable with respect to the cylinder and which is connected at its outer end to actuating pin 52 and its bearing sleeve 52a. The intermediate link plates 42 and 43 define openings therein for the receipt of actuating pin 52, and the ramrod 51 is connected to the bearing sleeve 52a. A pair of fluid lines 54 and 55 are connected to opposite ends of the cylinder 50 for controlling the operation of fluid-actuated ram 49.
As illustrated in FIG. 2, the retraction and distension of ramrod 51 from cylinder 50 causes the actuating pin 52a to move through an arc 54 about pivot pin 46. The actuating pin 52 moves from a position beyond the pivot pin 46 when the ramrod is distended as illustrated in FIG. 2 through the arc 54 to a position where the actuating pin 52 is on the same side of the pivot pin 46 as is cylinder 50 and mounting pin 45 (FIG. 3). When the actuating pin 52 is located beside the pivot pin 46, as when the center 52b of the actuating pin 52 is located at reference line 55, the actuating pin is then at its most effective lever arm with respect to pivot pin 46 and fluid-actuated ram 49, so that the actuating linkage assembly 49 then exerts its greatest upward or downward movement with respect to axle 24 and the railroad wheels 21 and 22. This arrangement is for the purpose of causing the actuating linkage to have its greatest rotational force about the pivot pin 46 as the flanged steel railroad wheels 22 first contact the rails 20 of the railroad and begin to support the vehicle 10. As the intermediate link plates 42 and 43 rotate in a counterclockwise direction (FIGS. 2 and 3) progressively more toward an upright attitude, progressively less force is required to continue their rotation for a given load. Also, as the wheel support arm is moved progressively further down in a clockwise direction through its arc it moves progressively more toward an upright attitude and progressively less force is required to continue its rotation for a given load. Thus, the relationship of the parts of the linkage assembly causes the assembly to become progressively more able to lift a load as the railroad wheels engage the tracks and begin to lift more and more weight of the vehicle.
Wheel support arm 36 is curved along its length to form a concave recess 58 on its upper surface, and the pair of actuating link plates 40 and 41 define a concave recess 59 on their forward (FIG. 2) or lower (FIG. 3) surfaces. When the fluid-actuated ram 49 is retracted, the axle 24 moves upwardly through its arc 56 until the axle and its axle bearing 38 are located in the position illustrated in FIG. 3, which places the axle bearing 38 approximately behind the support bearing 25, with the upper portion of the axle bearing 38 being above the lowermost portion of the support bearing 25, and with the axle bearing 38 being received in the concave recesses 59 of the actuating link plates 40 and 41. The curved surface 58 of the wheel support arm 36 then extends beneath and about the support bearing 25. This locates the axle bearing 38 at a relatively high elevation with respect to the vehicle, so that the railroad wheels will be retracted upwardly and far away from the road surface.
Also, each of the intemediate link plates 42 and 43 define a concave recess 57 on its upper surface. When the fluid-actuated rams 49 are retracted and the wheel assemblies are retracted to their position shown in FIG. 3, the cylinders 49 will protrude into the recesses 57 of the intermediate link plates 42 and 43.
Aligned openings 60 are formed in actuating link plates 40 and 41, and similar aligned openings are formed in the intermediate link plates 42 and 43, and when the railroad wheel assembly is distended as illustrated in FIG. 2, the openings are aligned with each other and a pin is insertable through the openings to lock the actuating linkage 39 in its distended or down position. The intermediate link plates 42 and 43 also define second aligned openings 62, and when the wheel assembly is retracted as illustrated in FIG. 3, the second aligned openings 62 are aligned with the openings 60 in the actuating link plates 40 and 41, and the pin can be inserted through the aligned openings to lock the wheel assembly in its up or retracted position.
While this invention has been described in detail with particular reference to preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinbefore and as defined in the appended claims.