Patent Publication Number: US-6708625-B1

Title: Greaseless door lock

Description:
PRIORITY CLAIM 
     This application claims the benefit of the U.S. Provisional Application No. 60/142,223, filed Jul. 2, 1999. 
    
    
     DESCRIPTION 
     This invention relates in general to a greaseless door lock, and more particularly to a greaseless door lock which is mounted on a door of a railroad car to secure the door in an open position or a closed position. 
     BACKGROUND OF THE INVENTION 
     The railroad industry employs a variety of railroad cars for transporting products. Many of these cars, such as boxcars or auto rack railroad cars, are enclosed to protect the products or vehicles being transported. Enclosed railroad cars generally include one or more sliding doors to provide access to the interior of the cars. The doors are generally mounted on upper and lower tracks which are attached to the frame of the car. The doors have conventional door locks to maintain the doors in an open position or a closed position. The conventional door locks must be lubricated with a standard lubricant such as grease. The grease attracts particles and other materials, generally creates a dirty environment and causes grease contamination in the interior of the cars. 
     This problem is especially undesirable in auto rack railroad cars which transport newly manufactured vehicles, including automobiles, vans and trucks. Auto rack railroad cars, known in the railroad industry as auto rack cars, often travel thousands of miles through varying terrain. The typical auto rack car is compartmented, having two or three decks or floors, a frame, two side walls, a roof and a pair of doors at each end of the car. The doors protect the auto rack car from illegal or unauthorized entry and prevent theft or vandalism of the vehicles. The doors also prevent flying objects from entering the car and damaging the vehicles. In transit, the doors are secured in the closed position. When the automobiles are being loaded or unloaded, the doors are secured in the open position. Examples of such doors for auto rack cars are generally illustrated in U.S. Pat. Nos. 3,995,563 and 4,917,021. 
     Each door in an auto rack car includes at least one door lock having a locking pin which engages a socket attached to the frame of the auto rack car. The grease and dirt builds up on these door locks, creates a dirty environment and causes grease contamination inside the auto rack cars which is highly undesirable for the transport of newly manufactured vehicles because the grease and dirt can damage the finishes of the vehicles. The grease also tends to drip or fall off the door locks onto the floor or door tracks of the auto rack car. Workers step in this grease and then track the grease into the new vehicles. Thus, the grease sometimes damages the interior carpeting in the new vehicles. 
     The Association of American Railroads (“AAR”) requires that the door locks and rollers be lubricated or greased every twelve months or sooner if necessary. The AAR also requires that the date on which the doors and rollers are lubricated be painted on the inside of the auto rack cars for tracking purposes. This requires extensive tracking procedures for this regular maintenance which increases the cost of operating the auto rack cars and decreases the efficiency of the use of the auto rack cars. 
     Accordingly, there is a need for a door lock for railroad cars, and in particular auto rack cars which does not need to be lubricated on a regular basis. 
     SUMMARY OF THE INVENTION 
     The present invention solves the above problems by providing a greaseless door lock for railroad cars and particularly auto rack railroad cars which eliminates the need to use grease or another lubricant to lubricate the door locks. The greaseless door lock of the present invention generally includes a steel C-shaped bracket having a side wall and spaced-apart upper and lower end walls attached to and extending transversely from the side wall. A mounting plate is attached to the bracket. The upper and lower end walls include aligned apertures for slidably receiving a steel locking pin. 
     The preferred embodiment of the greaseless door lock includes two semi-clyindrical replaceable plastic bushings, bearing members or collars (primarily referred to herein as “bushings”) mounted in each aperture to prevent the steel-on-steel contact between the locking pin and the inner edges of the end walls which defines the apertures. The locking pin maintains the bushings on the end walls in the apertures. The bushings are preferably molded from a polymer such as a moly disulfide filled nylon although they could be made from other suitable materials such as manganese, bronze, ceramics, UHMW polyethylene, delrin or urethane. The bushings eliminate the need for a lubricant between the steel locking pin and the steel end walls of the bracket. The greaseless door lock also includes a spring mounted on the locking pin, a washer mounted on the locking pin below the spring and a stop extending transversely though the locking pin below the washer, which co-act to provide the action for the locking pin. 
     The greaseless door lock may include an alternatively shaped bracket for different positions on the door and a further embodiment of the greaseless door lock of the present invention includes a cylindrical bushing, bearing member or collar maintained in each aperture by a locking clip. 
     It is therefore an object of the present invention to provide a greaseless door lock for doors on railroad cars. 
     Another object of the present invention is to provide a greaseless door lock for doors on railroad cars which eliminates the need to lubricate the door locks. 
    
    
     Other objects, features and advantages of the present invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an auto rack railroad car; 
     FIG. 2 is an end view of an auto rack railroad car illustrating the doors at one end of the car; 
     FIG. 3 is a fragmentary perspective view of the end of an auto rack car, the left hand door in open position and a conventional lower door lock for the left hand door; 
     FIG. 4 is an enlarged interior plan view of a conventional lower door lock for a right hand door in an auto rack car; 
     FIG. 5 is a fragmentary perspective view of a conventional upper door lock for a left hand door; 
     FIG. 6 is an interior plan view of a conventional locking assembly for a left hand door including interconnected upper and lower door locks; 
     FIG. 7 is a perspective view of a conventional lower door lock; 
     FIG. 8 is a perspective view of a conventional upper door lock; 
     FIG. 9 is a perspective view of a lower greaseless door lock of the present invention; 
     FIG. 10 is an exploded perspective view of the lower greaseless door lock of FIG. 9; 
     FIG. 11 is an enlarged perspective view of a semi-cylindrical collar, bearing member or bushing of the greaseless door lock of the present invention; 
     FIG. 12 is a side plan view of a semi-cylindrical collar, bearing member or bushing of the greaseless door lock of the present invention; 
     FIG. 13 is a top plan view of a semi-cylindrical collar, bearing member or bushing of the greaseless door lock of the present invention; 
     FIG. 14 is a plan view of the interior of a semi-cylindrical collar, bearing member or bushing of the greaseless door lock of the present invention; 
     FIG. 15 is a bottom plan view of a semi-cylindrical collar, bearing member or bushing of the greaseless door lock of the present invention; 
     FIG. 16 is a perspective view of an upper greaseless door lock of the present invention; 
     FIG. 17 is an exploded perspective view of the upper greaseless lock of FIG. 16; 
     FIG. 18 is an enlarged perspective view of an alternative cylindrical collar, bearing member or bushing and locking clip of the present invention; 
     FIG. 19 is a side plan view of the alternative cylindrical collar, bearing or bushing member of FIG. 18; and 
     FIG. 20 is a top plan view of the alternative cylindrical collar, bearing member or bushing of FIG.  18 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The greaseless door lock of the present invention eliminates the need to lubricate door locks on doors in enclosed railroad cars. A greaseless door lock of the present invention is described in detail below in relation to auto rack cars, although the present invention is also suited for box cars and other railroad cars. 
     Referring now to the drawings, and particularly to FIGS. 1 to  8 , a typical auto rack car  10  includes a frame  12  supported by trucks  14 , each of which have several wheels  16  which roll along railroad tracks  18 . The frame  12  supports two side walls  20  and a roof  22 . The auto rack car  10  includes a pair of coacting clamshell doors  24  and  26  mounted on each end of the auto rack car  10 . The doors  24  and  26  are opened to facilitate the loading and unloading of vehicles into and out of the auto rack car  10  and are closed during transport or storage of the vehicles. The right hand door  24  and the left hand door  26  (when viewed from the outside of the car) are shown in closed position in FIGS. 1,  2 ,  4  and  5 , and the left hand door  26  is shown in open position in FIG.  3  and in closed position in FIG.  6 . 
     As best illustrated in FIG. 3, the doors  24  and  26  are supported and guided at their bottom ends by lower door tracks  28  mounted on the frame  12  and are guided at their upper ends by upper door tracks (not shown). The steel door track  28  includes a first substantially horizontally disposed door wheel bearing member  30  and a substantially vertically disposed door guide member  32  integrally formed with the outer edge of the bearing member  30 . The door track  28  further includes a somewhat offset and higher second horizontally disposed member or ledge  34 . The member or ledge  34  includes two spaced apart sockets  38  and  40  for co-acting with a door lock  36  on door  26 . Socket  38  co-acts with a door lock  36  when door  26  is in closed position, and socket  40  coacts with a door lock  36  when door  26  is in the open position. The member or ledge  34  also includes a stop  39  associated with each socket  38  and  40  which limits the movement of the door. Stop  39  is illustrated in FIG.  3 . 
     The conventional door locks found in the prior art which are currently being used on railroad cars are illustrated in FIGS. 3 through 8. As specifically illustrated in FIG. 6, each door has a locking assembly  42  which includes a lower door lock  36  and an upper door lock  36   a  interconnected by a cable  70  which causes the door locks  36  and  36   a  to operate in unison to lock and unlock the doors. As illustrated in FIGS. 3,  4 ,  6  and  7 , the lower door lock  36  includes a vertically disposed locking pin  50  mounted in a substantially C-shaped bracket  52  which is mounted on the door. The locking pin  50  is aligned with and received in socket  38  if the door is in the closed position and aligned with and received in socket  40  if the door is in the open position. The door locks  36  include grease caps or grease fittings  63  and  64  on the upper and lower end walls  58  and  60  of the bracket  52  as illustrated in more detail in FIGS. 7 and 8. 
     The conventional door lock  36  also includes a spring  56  mounted on the locking pin  50  and disposed between the upper and lower end walls  58  and  60  of the bracket  52 . The spring  56  is bottomed at one end against the grease cap or fitting  63  on the upper wall  58  and at the other end against a washer  54  which is mounted on the locking pin  50 . The spring  56  normally urges the locking pin  50  downwardly. 
     An actuating lever  62  is pivotally mounted on the door and pivotally attached to the top end of the locking pin  50 . The actuating lever  62  is rotated or actuated using a key (not shown) which is inserted through keyholes  66  and  68  in the doors  24  and  26  as illustrated in FIG.  2 . The rotation of the actuating lever  62  causes an upward force on the locking pin  50  and a downward force on the outer free end of the actuating lever  62  which is connected to the cable  70 . When the actuating lever  62  is rotated, the cable  70  connected to the actuating lever  62   a  on the upper door lock  36   a  is likewise actuated to cause the locking pin  50   a  to disengage socket  38   a  on the upper deck or floor of the car to unlock the door and allow it to be moved either from closed position to open position or from open position to closed position as illustrated in FIG.  5 . 
     The upper door lock  36   a , as illustrated in FIGS. 5 and 8, has an alternatively shaped bracket, but generally has identical working parts including a locking pin  50   a , a spring  56   a , a washer  54   a  and grease caps or fittings  63   a  and  64   a . A stop  68  is associated with socket  38   a  in order to assist in stopping the door  26  when it reaches the closed position. The lower end of the locking pin  50   a  is beveled to facilitate entry of the locking pin  50   a  into the socket  38   a . Release of a force on the actuating lever  62   a  will allow the spring  56   a  to force the locking pin  50   a  downwardly so that it will sit in a socket  38   a  when the locking pin  50   a  is aligned with the socket  38   a  and thereby maintain the door in the open or closed position. 
     Referring now to FIGS. 9 through 15, one embodiment of a greaseless door lock  100  of the present invention includes a substantially C-shape bracket  102  having a side wall  104  and spaced-apart upper and lower end walls  106  and  108  integrally connected to and extending transversely from the side wall  104 . The end walls  106  and  108  include suitably sized aligned circular apertures  110  and  112 , defined by inner edges  111  and  113  of end walls  106  and  108 , respectively, for receiving a cylindrical locking pin  114 . A mounting plate  116  is attached to the bracket  102  and specifically welded to the side wall  104  and end walls  106  and  108  of the bracket  102 . The locking pin  114  extends through apertures  110  and  112  in the upper end wall  106  and lower end wall  108  and is secured in the bracket  102  by a spring  118  journaled about the locking pin  114 , a disc-shaped washer  120  journaled about the locking pin  114  below the spring  118  and a stop  122  extending transversely through a transverse slot  123  in the locking pin  114 . The stop  122  maintains or supports the washer  120 , and the spring  118  is buttoned or bottomed against the washer  120  to create the downward force on the locking pin  114  in a conventional manner. 
     As further shown in FIG. 10, a pair of upper collars, bearing members or bushings  124  and  126  are positioned in the aperture  110  between the outer circumference of locking pin  114  and the inner edge  111  of the upper end wall  106  which defines the aperture  110 . A pair of lower collars, bearing members or bushings  128  and  130  are positioned in the aperture between the outer circumference of locking pin  114  and the inner edge  113  of the lower end wall  108  which defines the aperture  112 . As illustrated in FIG. 9, the locking pin  114  is suitably sized to maintain the semi-cylindrical bushings  124 ,  126 ,  128  and  130  in place and prevent the displacement of the bushings. Bushings  124 ,  126 ,  128  and  130  are preferably identical. For purposes of this application, bushing  130  is described in greater detail below. 
     As further illustrated in FIGS. 11 through 15, bushing  130  includes a semi-clyindrical body  132 , a semi-cylindrical first or upper flange  134  extending transversely from the entire first or upper end of the semi-cylindrical body  132  and a semi-cylindrical second or lower flange  136  extending transversely from a portion of the second or lower end of the semi-cylindrical body  132 . The upper flange  134  may include a beveled edge  137 . The upper and lower flanges  134  and  136  define a semi-circular slot  135 . Slot  135  has a height which is slightly greater than the thickness of upper and lower end walls  106  and  108  so that bushing  130  can receive the inner edges  111  and  113  of end walls  106  or  108  which define the apertures  110  and  112 , respectively. The flanges  134  and  136  engage the top and bottom surfaces of the end walls  106  or  108  of the bracket as illustrated in FIGS. 9 through 11. 
     More specifically, the bushings  128  and  130  on lower end wall  108  are preferably mounted with the first or upper flanges  134  adjacent to or engaging the top surface of the end wall  108  as illustrated in FIGS. 9 and 10, and with the second or lower flanges  136  adjacent to or engaging the bottom surface of the end wall  108  to form a snug fit. The bushings  124  and  126  are mounted with the second or lower flanges adjacent or engaging the top surface of the end wall  106 , and with the first or upper flanges  134  adjacent to or engaging the bottom surface of the end wall  106 . This arrangement provides the greatest purchase area for the top of the spring  118  to engage the first or upper flanges  134  of bushings  124  and  126  and for the stop  122  to engage the first or upper flanges  134  of bushings  128  and  130 . Preferably, as illustrated in FIGS. 9 to  15  the first or upper flanges are larger than the second or lower flanges in the bushings of the present invention to facilitate ease of mounting the bushings in the aperture as will be appreciated by one of ordinary skill in the art. 
     The C-shaped bracket  102  is preferably made of a suitable metal such as steel, although it could be made of other suitable materials such as plastics, ceramics or composites. To form the steel C-shaped bracket  102 , a suitably sized blank steel plate is laser cut, burned or die cut to the desired profile. The appropriate apertures are punched at the desired locations in the plate to create apertures  110  and  112 . Thereafter, the plate is bent in a conventional manner using progressive dies to form the upper end wall  106 , the side wall  104  and the lower end wall  108 . The mounting plate  116  is then welded to the bracket  102 . Prior to installation, the C-shaped bracket  102  is preferably primed and painted with a suitable rust preventing primer and paint. It should be appreciated that the C-shaped bracket of the greaseless door lock of the present invention could be formed in any suitable alternative manner. 
     The bushings  124 , 126 ,  128 , and  130  are preferably injection molded from a moly disulfide filled nylon, although they could be made in other suitable manners and from other suitable materials such as delrin, urethane, ultra-high molecular weight polyethylene, manganese, bronze and ceramics. The bushings  124 ,  126 ,  128 , and  130  preferably have a low coefficient of friction to steel, dry self-lubricating and non-hygroscopic characteristics, a high compressive strength and a high resistance to wear. Although the bushings  124 ,  126 ,  128 , and  130  are usually protected from direct sunlight, the bushings  124 ,  126 ,  128 , and  130  could include an ultraviolet inhibitor. 
     An upper greaseless door lock  100   a  of the present invention is illustrated in FIGS. 16 and 17. The upper greaseless door lock  100   a  is substantially the same as greaseless door lock  100  except that its side wall  104   a  has a relatively larger surface area than side wall  104 , and the upper and lower end walls  106   a  and  108   a  of door lock  100   a  have relatively larger surface areas than upper and lower end walls  106  and  108 . The upper greaseless door lock  100   a  includes an L-shaped mounting bracket  140  attached to the top of upper wall  106   a . Mounting bracket  140  has a first plate  142  rigidly connected to the upper end wall  106   a  and a second plate  144  adapted for mounting door lock  100   a  to the door. To facilitate attachment of upper greaseless door lock  100   a  to the door, the second plate  144  includes an elongated slot  145  as shown in FIG.  16 . The bushing  124 ,  126 ,  128  and  130  are preferably employed in the upper greaseless door lock  100   a  as described above in regard to the greaseless door lock  100  as illustrated in FIG.  17 . 
     An alternative embodiment of the collars, bearing members or bushings of the greaseless door lock of the present invention is illustrated in FIGS. 18 through 20 and generally indicated by numeral  170 . The bushing  170  is a one-piece cylindrical member which includes a cylindrical body  176 , which defines an aperture  177  at least slightly larger than the locking pin, a flange  174  which extends transversely or outwardly from the entire first or upper end of the body  176 , and a cylindrical ring slot  178  formed in the body  176  below the flange  174 . The distance between the bottom of flange  174  and the top of cylindrical ring slot  178  is slightly greater than the thickness of the walls  106  and  108  such that the end walls  106  and  108  do not cover ring slot  178  when the bushings are inserted in aperatures  110  and  112 . 
     The ring slot  178  is adapted to receive a snap ring or locking clip  180 . The snap ring  180  is placed in the ring slot  178  to securely maintain the bushing  170  in the apertures in walls  110  and  112 . The bushing  170  is made preferably from the same material and in the same manner as bushing  130 . Snap ring  180  is commercially available in a variety of materials, though the preferable material is stainless steel to prevent rusting. 
     Although not shown, one bushing is preferably mounted in the aperature  112  in the lower end wall  108  with the flange  174  adjacent to or engaging the top surface of the end wall  108 , and with one snap ring  180  engaging or adjacent to the bottom surface of the end wall  108 . Although not shown, another bushing  170  is preferably mounted in the aperature  110  in the upper end wall  106  with the flange  174  adjacent or engaging the bottom surface of the end wall  106 , and with another snap ring  180  engaging or adjacent to the top surface of the end wall  106 . 
     It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention, and it is understood that this application is to be limited only by the scope of the claims.