Anti-spin/anti-drift module

Description

BACKGROUND OF THE INVENTION

This invention relates to the field of railroad car doors of the type that are pivoted into an out of closure openings in railroad cars and slide transversely of the wall of a railroad car when the door is open. Doors of this type are commonly referred to as plug doors. Anti-spin/anti-drift devices have been used on railroad car plug doors that use pivotal crank rod assemblies to support the door and crank activation rods that extend to a door operating handle assembly. Such operating handle assemblies have a selector gear with an interconnected activation drive pinion gear. Crank rods extend from the selector gear for opening and closing the door. The pinion gear has a handle for manual input thereto. Prior art anti-spin devices have a ratchet gear engaged by directional pawls. Such devices prevent rapid spinning of the handle in one direction if the door is accidentally moved by cargo or by an operator losing control of the handle during opening of the door. The anti-spin devices of this prior type can be found in U.S. Pat. Nos. 3,557,731; 3,660,938 and 4,920,894.

For years the closing and locking mechanism for plug-type railroad car doors have consisted of cranks depending from vertically oriented pipes rotationally secured to the doors and hand-operated gear mechanisms which rotate the pipes and cranks between open and closed positions. Upon rotation of the pipes in a direction to apply a closing force to the door, a gasket in the door frame is usually compressed to seal the door. When the door is released, the cranks rotate in the direction which moves the door laterally outwardly so that it will clear the door frame for longitudinal movement on tracks or rails extending along the length of the car. Since there is very little friction in the mechanism, the door when opened and positioned longitudinally away from the car opening, can move laterally into the car side.

Previous attempts to solve this problem such as in the aforementioned U.S. Pat. Nos. 3,555,731; 3,660,938 and 4,920,894 utilized a modified pinion generally with lugs that engage a flange and clamp a toothed wheel between the pinion and the flange with the toothed wheel movement controlled by a pawl to prevent uncontrolled movement of the operating handle during open and closing operations.

Another U.S. Pat. No. 6,546,611 shows an anti-spin device that replaces the single existing pinion gear with a pair of rotatable pinion gears that have extended engagement travel restriction lugs extending therefrom. The pinion gears are threadably positioned on a handle drive shaft with a ratchet gear assembiy being rotatably positioned over the respective lugs between friction rings and held in place by respective apertured pressure plates. Upon unintentional rapid rotation of the drive handle shaft, the friction rings wedgeably engage the ratchet gears stopping directional rotation of the pinion gear interconnected therewith.

SUMMARY OF THE INVENTION

This invention is directed to an anti-spin/anti-drift module for replacing existing railroad car plug door locking and anti-spin/anti-drift mechanisms. The module of this invention will allow the module to be a “drop-in” unit for a plug door. The gear housing will also set the compression on the pinion gear which will give a consistent torque for every plug door assembly.

The anti-spin/anti-drift gear design of this invention utilizes mechanical friction and a floating pinion as means to control torque through the segmental gear via a load on the door. Essentially a force on the plug door will not spin the operating handle, nor cause the plug door to drift in and out. A constant force is applied to the gear mechanism which allows for a smooth, consistent operation throughout the entire range of motion of the gear mechanism. To open or close the door, the spring force of the module is the main force to overcome. This force is set between 40 to 80 foot pounds on the operating handle, depending on the size of the door. The standard plug door operating mechanism has a 7.2:1 or a 10.13:1 gear ratio through which the power is transmitted to the main gear, connecting bars and pipe assemblies. Inversely, if a load is applied to a door, the gear ratio previously mentioned multiplied by the resisting force of the module will over come the inertia to open and close the door.

Other objects of the invention will be found on the following specification, claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention as shown more or less diagrammatically in the following drawings wherein.

FIG. 1 is a partial, broken away portion of a railroad car plug door with parts omitted, others shown in phantom lines and others broken away all for clarity of illustration;

FIG. 2 is an exploded view of the anti-spin/anti-drift module of this invention;

FIG. 3 is a cross sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is a cross sectional view taken along line 4-4 of FIG. 1; and

FIG. 5 is a perspective view of the anti-spin/anti-drift module of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 of the drawings shows a portion of a plug door 11 of a railroad car. The construction and operating mechanisms of such doors are old and well known in the art as are the anti-spin/anti-drift mechanisms previously used to control spinning of the plug door operating handle and drifting of the plug door when it is removed from the door opening or is moving along its support tracks along the side of the railroad car. Detailed descriptions of the operating mechanisms and prior art anti-spin/anti-drift mechanisms can be found in U.S. Pat. Nos. 3,557,731; 3,660,938; 4,920,894; and 6,546,611 which patents are incorporated by reference in this specification for all purposes. Only sufficient portions of the plug door and operating mechanisms which are necessary for an understanding of the operation of the module 13 of this invention and to completely describe the environment in which the module 13 of this invention functions will be specifically described herein. Reference should be made to the prior art patents mentioned above for additional details of the prior constructions and the environment in which the module of this invention will function.

The main elements of the plug door 11 operating mechanism with which the module of this invention interacts is the segmental gear 15, the operating handle 17 and the pinion gear shaft which is specifically designed for this module 13. Other elements of the structure of the plug door 11 and the plug door operating mechanism are shown in FIGS. 3 and 4 of the drawings of the specification.

FIG. 2 of the drawings is an exploded view of the module 13 of this invention. The module 13 is designed to be installed in or “dropped” into a conventional plug door operating mechanism to replace the conventional pinion gear, pinion gear shaft and anti-spin/anti-drift mechanisms installed therein. The module 13 includes a cylindrical gear housing tube 21 which is shown in the exploded view as open at its opposite ends. The opposite ends of this gear housing are closed by an inner bushing cap 23 at one end and an outer bushing cap 25 at the opposite end. The inner bushing cap 23 is mounted in a main bearing plate 27 and the outer bushing cap 25 is mounted in a bushing cover plate 29, both of which plates are conventional parts of a railroad car plug door and best viewed in FIG. 4 of the drawings. A pinion shaft 31 of this invention is journaled at its opposite ends in the inner and outer bushing caps 23 and 25 as can best be viewed in FIG. 2 of the drawings. The outer end 33 of the pinion shaft is threaded and the threads extend outwardly beyond the outer bushing cap 25 and through a handle adapter 35 so that a lock nut 37 can be threaded on the pinion shaft to fasten the handle adapter and handle 17 to the pinion shaft. Located immediately inwardly of the threaded end 33 is an industry standard square portion 39 of the pinion shaft for receiving the handle adapter. The handle adapter is conventionally welded to the operating handle 17.

The inner end 41 of the pinion shaft 31 is cylindrical in shape and is joumaled in the inner bushing cap 23. A friction disk 43 telescopes over the cylindrical end 41 of the pinion shaft and engages an annular flange 45 formed integrally with the pinion shaft. The friction disk is made of an aluminum bronze material such as that sold under the designation AMPCO 21 and functions as a replaceable wear element in the module 13. A portion 47 of the pinion shaft 31 is located between its flange 45 and its threaded end 33 and this portion is generally square in cross section with chamfered corners but is larger in cross-section than the industry standard square portion 39. A pinion gear 49 is mounted on the square portion 47 of the pinion shaft 31 so that it can move longitudinally on the pinion shaft but will rotate with the pinion shaft. Located on opposite sides of the movable pinion gear are pairs of dished spring or thrust washers 51 and 53. The dished spring or thrust washers referred to herein are disks of metal that are formed in an irregular shape so that when the washer is loaded it deflects, acts as a spring, and provides a preload between surfaces. As is conventional, the dished spring washers of each pair are positioned with their convex sides back to back. The spring washers 51 are captured between the flange 45 of the pinion shaft and the pinion gear. The spring washers 53 are positioned between the pinion gear and a thrust plate 55 which engages the outer bushing cap 25. The thrust plate 55 is formed of the same aluminum bronze material as the friction disk 43 but also has radial grooves 56 formed in its face for better gripping. An arcuate opening 57 is formed in the gear housing tube 21. An arm 59 is attached, as by welding, to the gear housing tube and extends away from the gear housing tube in a direction generally diametrically of the arcuate opening 57. A circular passage 61 is formed in the arm 59 near its distal end.

Upon assembly of the module 13, it is ready to be installed in a railroad car plug door 11. The gear housing tube 21 with its inner and outer bushing caps 23 and 25 welded thereto sets the compression forces acting against the pinion gear 49 by compressing the thrust washers 51 and 53 and forcing the friction disk 43 and thrust plate 55 against the thrust washers. The module 13 is installed in a plug door with its inner bushing cap 23 seated in the main bearing plate 27 and the outer bushing cap 25 seated in the bushing cover plate 29. A bolt 63 in the plug door extends through the passage 61 in the gear housing arm 59 (FIG. 3) to position and align the module relative to the plug door. With the module 13 positioned and aligned in the plug door, the pinion gear will be positioned adjacent the arcuate opening 57 in the gear housing tube 21 to mesh with the segmental gear 15 (FIG. 3) which extends through the arcuate opening. The threaded end 33 of the pinion shaft will extend through the outer bushing cap 25 in the bushing cover plate 29 and into the handle adapter 35 where it receives a lock nut 37 to fasten the operating handle 17 to the pinion shaft 31. The thrust washers 51 and 53 and the pinion gear 49 will be positioned on the pinion shaft 31 over the portion of the shaft having chamfers 65 of relatively narrow width. Thus, the thrust washers and the pinion gear will rotate with the pinion shaft. The thrust plate 55 will be positioned over the portion of the pinion shaft having relatively wider chamfers 67 which will permit the thrust plate 55 to rotate relative to the pinion shaft.

To open the plug door 11, the operating handle 17 is rotated in a counterclockwise direction as viewed in FIG. 1 of the drawings. Rotation of the handle 17 rotates the pinion gear 49 also in a counterclockwise direction. The pinion gear 49 meshes with and causes the segmental gear 15 to rotate in a clockwise direction releasing the connecting bars and pipe assemblies to move the plug door outwardly from the plug door opening in a conventional manner. Utilizing the module of this invention, a constant force is applied by the spring washers 51 and 53 which is between 40 to 80 ft. lbs. on the operating handle 17 depending on the size of the plug door. This constant force is applied to the entire range of motion of the operating handle. If a load is applied to the door, the constant force applied by the spring washers 51 and 53 will resist undesired drifting of the plug door when it is completely open or spin of the operating handle during the opening process.