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BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention provides an apparatus and method for replacing the tie plates of a railway. 
     2. Description of the Related Art 
     The rails of a railroad track are usually secured to cross ties by spikes driven into tie plates, with the tie plates located between the rail and the tie, and the head of the spike overlapping the bottom of the rail. The tie plates block lateral movement of the rails, and anchors are attached to the rail on either side of the tie are used to secure the rail against longitudinal movement. 
     Railroad ties occasionally must be replaced due to wear. After a tie is replaced, tie plates must be provided between the rail and the tie so that the rail may be properly secured to the tie. 
     Several other references propose various systems for use in replacing tie plates. For example, U.S. Pat. No. 4,280,613, issued to J. K. Stewart on Jul. 28, 1981, describes a tie plate conveying and orienting system. 
     U.S. Pat. No. 4,770,103, issued to F. Allmer on Sep. 13, 1988, describes a rail clamp. The rail clamp includes a pair of line-up wheels for engaging the inside edges of the rails. A pair of pivoting clamping arms, with each clamping arm having a disk rotatably mounted to its end, engages the outside edge of each rail, just below the rail&#39;s ball. Movement of the clamping arms is controlled by hydraulic cylinders. Additionally, a stabilizer cylinder connecting a bridge crossing the chassis to the rail lifting assembly may either permit the rail lifting assembly to float to correspond with the rails, or may be locked in position. 
     U.S. Pat. No. 4,733,614, issued to G. Mohr et al. on Mar. 29, 1988, describes a machine for repairing a railway track. The machine includes a main chassis having various devices for repairing a railway, mounted on a chain drive under a railway vehicle. A counter weight mounted to the chain drive, moving the opposite direction, counters the effects of inertia. 
     U.S. Pat. No. 4,942,822, issued to D. J. Cotic on Jul. 24, 1990, describes an apparatus and method for automatically setting rail tie plates. The apparatus includes a frame having a ramp thereon. The ramp stores the tie plates, and includes a control mechanism for releasing them one at a time into a plate pocket. A reciprocated pusher then moves the plate from the plate pocket to its position on the tie. 
     U.S. Pat. No. 5,067,412, issued to J. Theurer et al. on Nov. 26, 1991, describes a tie plate-inserting machine. The front of the machine includes a crane broom with a tie plate-collecting magnet. A funnel adjacent to the crane leads to a conveyer, which terminates above a sorting table. A roller conveyer conveys ties from the sorter to a magazine. The magazine moves between a level position for receiving tie plates from the sorting table, and a lower position for dispensing the tie. The machine includes a tie plate-inserting arm slidably supported by a guide rod, for pushing the-tie plates from the magazine to their position below the rail. A lifting roller pivots between a raised position and a lowered position for permitting tie plates to be pushed thereon from the magazine to their final position below the rail. 
     U.S. Pat. No. 5,193,461, issued to J. Theurer et al. on Mar. 16, 1993, describes a tie exchange mean for both removing ties and inserting new ties. The tie exchange machine may move longitudinally along a guide track. A scarifier and track-lifting device are included. A mobile tie transporting crane may move towards or away from the tie exchange device, for transporting either new ties to be installed or old ties which have been removed. The tie-depositing device is a vertically adjustable forklift. 
     U.S. Pat. No. 5,305,692, issued to H. Madison et al. on Apr. 26, 1994, and assigned to Harsco Corporation, the assignee of the present invention, describes a tie exchanger mounted on a truck. The tie exchanger has a rail clamp table having rail clamps and a boom. The boom includes a tie clamp, and may pivot around the vertical axis to insert ties from either side of the tracks. 
     U.S. Pat. No. 5,331,899, issued to J. D. Holley on Jul. 26, 1994, describes a tie plate installer and remover using a magnetic wheel to insert or remove a tie plate. The tie plate installer includes a tie magazine from which tie plates are dropped into a shoot leading to the magnetic wheel, which then carries the tie plate to a position on the tie adjacent to its final location under the rail, and finally pushes it under the rail. 
     U.S. Pat. No. 5,419,259, issued to J. Theurer et al. on May 30, 1995, describes a ballast stabilizer. The ballast stabilizer has a rail clamp including a roller for engaging the rail&#39;s ball, mounted on an arm secured at its other end to a lever. The opposite arm of the lever is secured to a hydraulic cylinder, so that extending the cylinder pushes inward on the clamp arm. A pair of vertical inner wheels are pushed against the gauge side of the rail&#39;s ball by hydraulic cylinders. A shaking apparatus vibrates the machine parallel to the ties. 
     U.S. Pat. No. 5,722,325, issued to K. E. Glomski et al. on Mar. 3, 1998, describes a tie replacement apparatus including drip elements for holding a tie plate in place while the tie underneath is replaced. 
     U.S. Pat. No. 5,839,377, issued to D. M. Brenny et al. on Nov. 24, 1998, describes a machine for installing and removing elastic rail clips of the type used for fastening rails to concrete or wooden ties. 
     U.S. Pat. No. 6,170,401, issued to R. Miller et al. on Jan. 9, 2001, describes a rail vehicle for collection and distribution of railroad cross ties. 
     When replacing tie plates, it is useful to position the human operator where he may observe the operation, and make corrections as necessary. Additionally, it would be helpful for an operator in this position to be able to control movement of the vehicle to which the tie plate replacement apparatus is secured, thereby permitting rapid progression from one tie plate to the next. Furthermore, it is desirable to have the ability to utilize the tie replacement apparatus from different locations on the vehicle, depending on the nature of the obstacles surrounding the vehicle, for example, platforms, bridges, etc. Accordingly, a railway tie replacement apparatus and method incorporating these features is desired. 
     SUMMARY OF THE INVENTION 
     The present invention provides a railway tie insertion vehicle. The vehicle includes an operator&#39;s chair on either side of the vehicle, with a main rail clamp and tie plate magazine located in close proximity to the operator&#39;s chair. A secondary rail clamp is located at the rear of the vehicle. Each operator is provided with a tie plate insertion wand that may be utilized from either the side or the rear of the vehicle, and which includes controls for the vehicle. 
     The main rail clamps are located between the wheels of the vehicle. The rollers are placed underneath the rails&#39; ball where they roll along the rail until lifting is desired. When raising a rail is desired, lifting the clamp will cause the scissor arms to be drawn together, thereby gripping the rail and lifting it a sufficient distance to permit removal and insertion of the tie plate. Hydraulic cylinders are provided for moving the scissor arms away from the ball when unclamping the rail is desired. Additionally, a stabilizer cylinder connecting the wheel and frame assembly to the rail lifting assembly locks the rail in place laterally as the rail is raised, preventing buckling of the rail. The stabilizer cylinder also permits the operator to move the rail laterally in either direction to correct misalignment of the rail. 
     A secondary rail clamp, utilizing the same scissors mechanism but without the rollers, is located at the rear of the machine, permitting tie plates to be inserted from inside the tracks when the machine is used next to a platform or on a bridge, where access to the rail from the outside is restricted. 
     An operator&#39;s chair is provided on either side of the vehicle, with each operator also having a tie plate insertion wand with a set of vehicle controls. Each operator has the ability to propel the vehicle, apply the brakes, control the rail clamps, adjust the rail lift on their individual sides, activate the emergency stop and shut-down mechanism, and blow the vehicle&#39;s horn. The wand extends from the control box to a position adjacent the rail, wherein it may be used to manually push a tie plate under the rail. The control box attached to the wand is connected to the vehicle or electrical system through quick disconnect electrical connectors permitting it to be moved to the vehicle&#39;s rear for use with the secondary clamps. 
     In general, tie plate will be deposited along the rail in advance of the tie plate replacement operation, so that the operators will not normally need to utilize a tie plate transported on the vehicle. However, in the event that a tie plate is not deposited in the location where it is needed, the vehicle does include a tie plate magazine, holding the tie plates vertically stacked. When a new tie plate is needed, the operator can activate a hydraulic pusher, which pushes the bottom tie plate from the magazine onto a ramp, so that the tie plate will slide down off the vehicle, landing adjacent to the rail. 
     The operator will control the vehicle from its cab when travelling to and from a work location. During a tie replacement operation the movement of the vehicle can be controlled by the operators on either side of the vehicle. The vehicle will travel along the track, stopping at each location wherein the tie plate must be replaced. The operators will use the scissors clamp to raise the rail, with the stabilizer cylinder plus the rail clamp&#39;s location between the wheels of the vehicle preventing buckling of the rail while it is being lifted. The operator will use their wand to manually push the old tie plate out from under the rail. If a new tie plate has been deposited along the rail, the operator will simply use the wand to manually push the new tie plate into place. If not, then the operator will actuate the pusher for the tie magazine, driving a tie from the bottom of the magazine onto the ramp, where it will fall into position adjacent to the rail. The operator may then manually push the new tie into place, just as he would if it had been previously deposited. The operators will then,lower the rail, and move to the next tie replacement location. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a railway tie plate insertion vehicle according to the present invention. 
     FIG. 2 is a front view of a rail clamp and a pair of tie plate insertion wands, according to the present invention. 
     FIG. 3 is an isometric view of a rail clamp according to the present invention, illustrating the clamp on one side open, and the clamp on the other side closed. 
     FIG. 4 is a cross-sectional front view of a rail clamp according to the present invention, illustrating one clamp in its closed position, and a second clamp in its open position. FIG. 5 is a cross-sectional front view of a tie plate insertion vehicle according to the present invention. 
     FIG. 6 is a top view of an operator&#39;s chair and tie plate magazine for a railway tie plate insertion vehicle according to the present invention. 
     FIG. 7 is an isometric view of a tie plate insertion wand according to the present invention. 
     FIG. 8 is an isometric view of a tie plate insertion wand according to the present invention. 
     FIG. 9 is an isometric view of a tie plate magazine according to the present invention. 
     FIG. 10 is an isometric view of a tie plate magazine according to the present invention. 
    
    
     Like reference numbers denote like elements throughout the drawings. 
     DETAILED DESCRIPTION 
     The present invention provides an apparatus and method for installing new railway ties in a railway track. 
     Referring to FIGS. 4-5, a typical railway  10  includes pair of rails  12  supported by ties  14 . The ties  14  are typically imbedded in ballast to prevent their movement. A tie plate  16  fits between the rail  12  and the tie  14 , with a plurality of spikes passing through the tie  14  and tie plate  16 , and having their heads overlap the bottom flange of the rail  12 . The spikes and tie plate  16  thereby secure the rail  12  against transverse movement. A rail anchor  19  fits on either side of the tie  14 , and is generally secured to the gauge side or the rail  12 . The rail anchor  19  prevents longitudinal movement of the rail  12  with respect to the tie  14 . The top surface of the rail  12  forms the rail&#39;s ball  20 , which supports the wheels of railway vehicles. Adjacent sections of rail  12  may be joined using joint bars  21 . 
     During a tie  14  replacement operation, it is necessary to replace the tie plates  16 . The present invention is directed towards the insertion of new tie plates  16  between the rails  12  and ties  14 . 
     Referring to FIG. 1, the vehicle  20  includes a chassis  22 , supported by a plurality of wheels  24 . The front  26  of some preferred embodiments includes a motor  28  for propelling the vehicle  20 . The front  26  may also include a fuel tank, a hydraulic fluid tank, hydraulic fluid pump, and other components necessary to operate the vehicle  20 . The front  26  may also include a ballast plow  29 . The back  30  of the vehicle  20  includes a cab  32 , containing a driver&#39;s chair  34 , vehicle controls  36 , and a passenger bench  38 . 
     The center portion  40  of the vehicle  20  includes a rail clamp assembly  42 , for lifting the rails  12  a sufficient distance to permit insertion of a tie plate  16 , which will typically be approximately one to two inches. The rail clamp assembly  42  is best illustrated in FIG.  2 . The rail clamp assembly includes a crossbeam  44 , secured to the top of the chassis  22 . A hydraulic cylinder  46  depends from each end of the crossbeam  44 . The hydraulic cylinders  46  support a lower crossbeam  48  at their bottom ends. A stabilizer cylinder  50  extends between the chassis  22  and the lower crossbeam  48 , with the cylinder  50  oriented in a substantially horizontal direction, and substantially perpendicular to the rails  12 , although some deviation is permissible. A pair of clamping arms  52 ,  54  depend from one end of the lower cross beam  48 , and a mirror image pair of clamping arms  56 ,  58  depend from the other end of the lower cross beam  48 . The clamping arms  52 ,  54 ,  56 ,  58  are pivotally mounted to the lower cross beam  48  at pivots  60 ,  62 ,  64 , and  66 , respectively. The clamping arms  52 ,  54  cross over each other, opening and closing with a scissors-like action. Likewise, clamping arms  56 ,  58  also cross over each other, opening and closing with a scissors-like action. Each of the clamping arms  52 ,  54 ,  56 ,  58  terminates in a roller  68 , which defines a circumferential channel  70  between a pair of raised edges  72 . The channel  70  and raised edges  72  are dimensioned and configured so that the rollers  68  may engage a rail  12  with theentire roller  68  below the rail&#39;s ball  18  (most commonly used), or with the rail&#39;s ball  18  within the channel  70  (useful when engaging a rail  12  above the joint bars connecting adjacent rails  12 ). Hydraulic cylinders  74 ,  76  are connected between the lower cross beam  48  and clamping arms  54 ,  56 , respectively, for opening and closing the clamp  42 . A roller  78  is provided between each pair of arms  52 ,  54 , and  56 ,  58 , where it will sit on top of the rail&#39;s ball  18  when the rollers  68  are under the ball  12 . 
     Referring to FIGS. 3-4, some preferred embodiments of the present invention may include a second clamp  80 , located at the back  30  of the vehicle  20 . The second clamp assembly  80  is in many respects similar to the first clamp assembly  42 . The clamp assembly  80  includes a cross beam  82 , which may be raised and lowered using a hydraulic cylinder  84 , connected between the cross beam  82  and the chassis  22 . A pair of clamping arms  86 ,  88  depend from one end of the crossbeam  82 , and a mirror image pair of clamping arms  90 ,  92  depend from the other end of the cross beam  82 . The clamping arms  86 ,  88 ,  90 ,  92  are pivotally secured to the crossbeam  82  at pivots  94 ,  96 ,  98 ,  100 , respectively. The clamping arms  86 ,  88  thereby cross over each other, and will open and close with respect to each other using a scissors-like action. Likewise, the clamping arms  90 ,  92  also cross over each other, and will open and close with respect to each other using a scissors-like action. Each clamping arm  86 ,  88 ,  90 ,  92  terminates in a clamping tip  102 , defining a horizontal channel  104  thereon, between a pair of raised edges  106 . The channel  104  and raised edges  106  are dimensioned and configured so that the entire clamping tip  102  may fit below the rail&#39;s ball  18  (the normal grasping position), and so that the ball  18  may fit within the channel  104  (when clamping a rail  12  above a joint bar joining adjacent rail sections  12 ). A roller  108  also depends from the cross beam  82 , and is dimensioned and configured to engage the top of the rail&#39;s ball  18  when the clamping tips  102  are beneath the rail&#39;s ball  18 . The clamp assembly  80  also includes a pair of pusher arms  110 ,  112 , with one pusher arm  110  located adjacent to the clamping arms  86 ,  88 , and the other pusher arm  112  located adjacent to the clamping arms  88 ,  90 . The pusher arms  110 ,  112  each terminate in a foot  114  dimensioned and configured to engage the top of a tie  14 . The pusher arms  110 ,  112 , are mounted for vertical sliding movements with respect to the cross beam  82 , with the position of each pusher arm  110 ,  112  controlled by a hydraulic cylinder  116 . 
     The center portion  40  of the vehicle  20  also includes an operator&#39;s chair  118  on either side. Each operator&#39;s chair  118  is provided with a tie plate insertion wand  120 . The tie plate insertion wand  120  is best illustrated in FIGS. 7-8. The tie plate insertion wand  120  includes a pusher rod  122  having a control box  124  at its upper end and a foot  126  at its lower end, dimensioned and configured to facilitate pushing a tie plate  16 . Many preferred embodiments of the control box  124  include all controls necessary to operate the vehicle  20 , including propelling the vehicle  20 , apply the brakes, activate the emergency stop and shutdown mechanism, blow the vehicle&#39;s horn, operating the tie clamp assemblies  42 ,  80 , adjust the rail lift on their individual sides, and dispensing a tie plate  16  from a tie plate magazine (described below). A cable  128 , preferably terminating in a quick disconnect  130 , provides for electrical connection between the control box  124  and the vehicle  20 , thereby permitting the transmission of control signals therebetween. The quick disconnect  130  permits the tie plate insertion wand  120  to be moved from the vehicle&#39;s central portion  30 , wherein it may be used from an operator seated within the chair  118 , to the back  30  of the vehicle  20 , wherein it may used by someone following the vehicle  20 . The tie plate insertion wand  120  may include handles  132 ,  134 ,  136  to facilitate manipulation of the tie plate insertion wand. 
     Referring to FIGS. 9-10, the vehicle  20  may also include a tie plate magazine  138 . The tie plate magazine  138  includes four sidewalls  140 ,  142 ,  144 ,  146 , and an angled bottom  148 . A ramp  150 , having approximately the same angle as the bottom  148 , is positioned with its top end directly adjacent to the bottom  148 . The bottom end of the ramp  150  terminates just above the level of the ties  14 . A slot  152  within the sidewall  140  is dimensioned and configured to permit passage of the lower-most tie plate  16  within the magazine  138  from the magazine  138  to the ramp  152 . A tie plate pusher assembly  154  is provided for pushing the lower-most tie plate  16  from the magazine  138  to the ramp  150 . The pusher assembly  154  includes a pusher  156 , and a hydraulic cylinder  158  secured between the pusher  156  and vehicle chassis  22 . 
     In use, the vehicle  20  will be driven to the railway section upon which repairs are needed, with the work crew riding in the cab  32 . When the work site is reached, two operators will exit the cab  32 , sitting the chairs  118 . They will secure the quick disconnect  130  of their tie plate insertion wands  120  to the mating quick disconnects in the central portion  40  of the vehicle  20 , thereby permitting them to control the vehicle from the chairs  118  instead of the cab  32 . When the operators are using the chairs  118 , the main tie clamp assembly  42  will be utilized, with the secondary tie clamp assembly  80  left in its open and raised travel position. The cylinders  46  will be extended until the rollers  68  are located on either side of the rail  12 , directly beneath the rail&#39;s ball  18  of each rail  12 . The hydraulic cylinders  74 ,  76  will be extended, thereby securing the clamp assembly  42  in this position. The rollers  68  will permit the clamp assembly  42  to roll along the rails  12  in a clamped but relaxed configuration until a location is reached wherein a tie plate  16  needs to be replaced. 
     The operators will use the control boxes  124  to drive the vehicle  20 , stopping the vehicle  20  so that its central portion  40  is aligned with the tie  14  for which the tie plate  16  must be replaced. Again using the control boxes  124 , the operators will retract the cylinders  46 , thereby lifting the rails  12  approximately one to two inches above the tie  14 . The scissor arms  52 ,  54 ,  56 ,  58  will be clamped more tightly around the rail  12  through the combination of this lifting motion and their scissoring action. Typically, a new tie plate  16  will previously have been deposited in a location along side that wherein it will be installed. In the event that a tie plate  16  was not previously deposited, the operator on the side of the vehicle  20  wherein the tie plate  16  is missing will utilize his control box  124  to actuate the hydraulic cylinder  158  of the tie plate pusher  154 , thereby dispensing a tie plate  16  from the magazine  138  to the ramp  150 . The tie plate  16  will then descend the ramp  150  under its own weight, thereby being deposited in close proximity to its final desired location under the rail  12 . In either case, the operator will use the tie plate insertion wand  120  to manually push the tie plate  16  into its proper location between the tie  14  and rail  12 . Again using the control box  124 , the operators will extend the cylinders  46 , thereby lowering the rails  12  onto the tie plates  16 . The operators will then drive the vehicle  20  to the next location wherein a tie plate  16  must be replaced. 
     In some instances, it may be desirable or necessary to insert a tie plate  16  from the gauge side of the rail  12  instead of from the field side. Examples of such situations include locations next to curve blockers or elevated platforms, or possibly on a bridge. Additionally, the secondary clamp assembly  80  provides redundancy in case problems developed with the primary clamp assembly  42 . To use the secondary clamp assembly  80 , the operators will detach the quick disconnect  130  of the tie plate insertion wands  120  from the central portion  40  of the vehicle, connecting them to identical mating quick disconnect portions at the back  30  of the vehicle  20 . Once the vehicle  20  is in a location wherein a tie plate  16  must be replaced, the clamp assembly  80  is lowered until the rollers  108  contact the rail  12 , and then the arms  86 ,  88 ,  90 ,  92  are closed around the rails  12 . The hydraulic cylinders  116  are extended, thereby pushing the arms  110 ,  112  downward, raising the clamp assembly  80 , thereby lifting the rails  12 . This lifting action, combined with the scissor mechanism of the arms  86 ,  88 ,  90 ,  92 , tightens the grip of the arms  86 ,  88 ,  90 ,  92  on the rails  12  as the clamp assembly  80  is lifted. As before, the operators will use the tie plate insertion wands  120  to push the tie plates  16  into position between the rails  12  and ties  14 . If a tie plate was not deposited in the proper location prior to commencing this task, a tie could be dispensed from the tie plate magazine  138 , which ideally should be done from the central portion  40  of the vehicle  20 , before the back  30  of the vehicle  20  reaches the exact work location. Once the tie plates  16  are properly positioned, the operators use the control boxes  124  to lower the clamp assembly  80 , and open the clamping arms  86 ,  88 ,  90 ,  92 . 
     While a specific embodiment of the invention has been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.

Summary:
A railway tie plate insertion vehicle includes operator&#39;s chairs mounted on both sides of the vehicle; with the occupants of each chair being provided with a tie plate insertion wand including controls for movement of the vehicle. A tie magazine deposits a tie plate on the tie upon actuation by the operator when a tie plate has not been previously deposited. A first rail clamp includes a pair of rollers for engaging the rail, attached to the ends of a pair of scissor arms, so that raising the rail draws the scissor arms closer together, increasing the gripping pressure on the rail. A similar rail clamp is located at the rear of the vehicle, which also includes an electrical connection for the operator&#39;s wand, thereby permitting tie plate insertion from the rear of the vehicle when obstacles are present along the sides of the vehicle.