Abstract:
A lifting bracket assembly is disclosed. The lifting bracket assembly includes a motor, a pair of gear heads mechanically coupled to the motor such that each of the gear heads is coupled to a jack screw connector, a first and second jack screw, wherein each of the jack screws is coupled to one of the jack screw connectors and one of the gear heads, a first lifting bracket rotatably coupled to the first jack screw, a second lifting bracket rotatably coupled to the second jack screw, wherein the first and second jacks screws are different, a first guide tube fixedly coupled at a first end to the first lifting bracket and coupled to a first rail beam at a second end, and a second guide tube fixedly coupled at a first end to the second lifting bracket and coupled to a second rail beam at a second end.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present patent document claims the benefit of the filing date under 35U.S.C. §119(e) of Provisional U.S. Patent Application Ser. No. 61/389,970, filed Oct. 5, 2010, which is hereby incorporated by reference, and is related to U.S. utility patent application Ser. No. 12/345,151, titled “JACK SCREW CONNECTOR,” filed on Dec. 29, 2008, the entire contents of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     This patent relates to car hoist systems and more particularly to a lifting bracket assembly and jack screw connector for use in a shallow pit car hoist system. 
     BACKGROUND 
     Car hoist systems may be designed or configured to include a wide selection of synchronized mechanical screw lift components, gear ratios, controls and power options. A typical car hoist system may be designed and configured to accommodate a variety of car types such as, for example, single units, married pairs and/or articulated cars. To accommodate and support the desired variety of car types, the car hoist system and components of the car hoist system can be adapted or arranged to support a wide range of lift heights, vehicle weights and dimensions. 
     Shallow pit car hoist systems are one type of car hoist system that may be utilized. A typical shallow pit car hoist system may operate and lift a vehicle with a pit depth of only three and a half feet (3′6″). The limited pit depth reduces excavation, construction and installation costs when compared to alternate deep pit designs, Moreover, the maintenance of the shallow pit car hoist system may be simplified when compared to alternate deep pit designs because the lifting screws may be housed in an oil-filled caisson that provides continuous oil bath lubrication to the screw and nut. This configuration protects the screw from environmental contamination and continuously lubricates the lifting screws thereby increasing the wear life of the nut and screw. 
     It would be desirable to provide a lifting bracket assembly and jack screw connector that may connect the lifting screws and drive mechanisms while allowing and/or compensating for any misalignment between the components. 
     SUMMARY 
     The exemplary jack screw connector disclosed and discussed herein provides a flexible connection that accommodates lateral movement or misalignment between the lifting or jack screws and the moving components, drive mechanisms, etc. of the vehicle lift equipment. The exemplary jack screw connector is configured to transmit high axial loads in combination with a torque load to the lifting or jack screws which, in turn, actuate a lifting frame to raise the vehicle. 
     In one embodiment, a lifting bracket assembly system is disclosed. The lifting bracket assembly includes a motor, a pair of gear heads mechanically coupled to the motor such that each of the gear heads is coupled to a jack screw connector, a first and second jack screw, wherein each of the jack screws is coupled to one of the jack screw connectors and one of the gear heads, a first lifting bracket rotatably coupled to the first jack screw, a second lifting bracket rotatably coupled to the second jack screw, wherein the first and second jacks screws are different, a first guide tube fixedly coupled at a first end to the first lifting bracket and coupled to a first rail beam at a second end, and a second guide tube fixedly coupled at a first end to the second lifting bracket and coupled to a second rail beam at a second end. 
     A method for assembling a lifting bracket assembly is also disclosed. The lifting bracket assembly including a frame, a guide bracket supported by the frame, a jackscrew connected to a jackscrew connector and gearhead, with the gearhead connected to the frame. A lifting bracket is aligned and rotatably coupled to the jack screw. A guide tube is slidably aligned with a guide bracket. The guide tube has a first end and a second end opposite the first end for supporting a beam. The guide tube is aligned and fixedly connected at the first end to the lifting bracket. 
     Additional features and advantages of the disclosed embodiments are described in, and will be apparent from, the following Detailed Description and the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  illustrates a perspective view of an exemplary jack screw connector; 
         FIG. 2  illustrates a side view of the exemplary jack screw connector shown in  FIG. 1 ; 
         FIG. 3  illustrates an exploded perspective view of the exemplary jack screw connector shown in  FIG. 1 ; 
         FIG. 4  illustrates an assembled perspective view of the exemplary jack screw connector coupled to a jack screw and gear box; 
         FIG. 5  illustrates an exemplary lifting bracket assembly and jack screw connector; 
         FIGS. 6 to 10  illustrate assembly drawings of the exemplary lifting bracket assembly shown in  FIG. 5 ; and 
         FIG. 11  illustrates an exploded view of a lifting bracket sub-assembly. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary jack screw connector disclosed and discussed herein provides a flexible connection that accommodates lateral movement or misalignment between the lifting or jack screws and the moving components, drive mechanisms, etc. of the vehicle lift equipment. The exemplary jack screw connector is configured to transmit high axial loads in combination with a torque load to the lifting or jack screws which, in turn, actuate a lifting frame to raise the vehicle. 
     One embodiment of an exemplary jack screw connector may be designed and configured to support, for example, a tensile load of eighteen thousand pounds (18,000 lbs.) and may include a female threaded connector to engage or cooperate with two and seven-eighths inch (2⅞″) diameter threads of a lifting or jack screw. Another embodiment of an exemplary jack screw connector may further include opposite the threaded female connector, a bore for supporting a keyed rod for coupling to a gearbox. Another embodiment of an exemplary jack screw connector may further be coated utilizing a wear resistant and/or lubricating coating such as, for example, a MICROLON® 1052 coating provided by Mircosurface Corporation of Morris, Ill. 
       FIG. 1  illustrates a perspective view of an exemplary jack screw connector  100 . The jack screw connector  100  includes a lower connector or clevis  102  and an upper connector or clevis  104  pivotably connected to or cooperating with an eye block  106 . As used herein, the term connector or clevis describes a substantially U-shaped component configured or adapted to pivotably cooperate with the eye block  106 . The eye block  106  supports a pair of orthogonally or transversely oriented, with respect to each other, shafts or pins  102 A and  104 A pivotably coupled to the clevises  102 ,  104 , respectively. The pins  102 A and  104 A each may be formed or manufactured with a pair of snap-ring grooves  108  (see  FIG. 2 ) sized to accept a snap-ring  110 . The eye block  106  supports and reinforces each of the shafts or pins  102 A and  104 A carried therein as well as each leg of the U-shape portion of the clevises  102 ,  104  relative to the base of the U-shape. In this way, the eye block  106  may contain and/or prevent undue flexing of each of the shafts or pins  102 A and  104 A and minimize the torque applied to each leg of the U-shape portion of the clevises  102 ,  104  as a load is applied thereto. 
     Each connector or clevis  102 ,  104  includes a chamfered or angled portion  112  formed at a distal end of each leg of the U-shape relative to the base of the U-shape. The chamfered portion  112  on each of the clevises  102 ,  104  ensures or allows for an adequate range of motion without contact relative to each of the clevises  102 ,  104 . The combination and freedom of movement afforded between the pivotably coupled to clevises  102 ,  104  provides for or allows for a connection to be established and rotatably maintained between a shaft (not shown) coupled along the rotational axis CL 1  associated with the lower clevis  102 , and a device (not shown) coupled along the rotational axis CL 2  associated with the upper clevis  104 . 
     The lower clevis  102  may support a female threaded portion  114  for connecting to a jack screw  400  (see  FIG. 4 ). The upper clevis  104  may include or cooperate with a load bolt  200  (see  FIG. 2 ) having a keyed portion  202  and a threaded portion  204 . The load bolt  200  may be configured to cooperate with a gear box  402  (see  FIG. 4 ) and convey a load between the lower and upper clevises  102 ,  104 . A locking pin  116  may be bored through the lower clevis  102  and configured to engage and secure the jack screw  400  when cooperating with the female threaded portion  114 . In an alternate embodiment, the locking pin  116  may be replaced with a set screw (not shown). The set screw (not shown) may cooperate with a tapped through hole provided in the lower clevis  102 . The set screw (not shown) may be arranged to engage and secure the jack screw  400  and/or a tapped hole (not shown) provided within the jack screw  400 . 
       FIG. 3  illustrates an exploded perspective view of the exemplary jack screw connector  100 . The lower clevis  102  supports and carries the eye block  106  between the legs  300 ,  302  that define the U-shape. The eye block  106  is sized such that the legs  300 ,  302  of the lower clevis  102  and the legs  304 ,  306  are slidable and pivotable relative to the outer surfaces of the eye block  106  while supporting the pins  102 A and  104 A carried within the orthogonally oriented through-bores  308 ,  310 , respectively. The surface of the through-bores  308 ,  310 , the surface of the pins  102 A and  104 A and any other surface that may experience friction, can be coated with, for example, a 0.0007″ MICROLON® 1052 coating to reduce frictional wear thereon. 
     The load bolt  200  may include a load bolt head  312  formed distal to the threaded portion  204 . A keyway  314  sized to accept a substantially rectangular key  316  may be formed adjacent to the load bolt head  312 . The key  316  may be accepted within a mating keyway  318  formed in the upper clevis  104 . The load bolt head  312 , the keyway  314  and key  316  may cooperate with a countersunk portion  320  formed in the upper clevis  104 . 
       FIG. 4  illustrates an assembled perspective view of the exemplary jack screw connector  100  coupled to the jack screw  400  and the gear box  402 . In particular, the load bolt  200  is aligned and carried within the gear box  402  via a key (not shown) carried within the keyway  202  and a complimentary keyway (not shown) disposed within the interior of the gear box  402 . In operation, the gear box  402  may be positioned such that axes CL 3  and CL 4  are substantially aligned. Any misalignment between the axis CL 3  and the axis CL 4  can be compensated for by the cooperation of the lower and upper clevises  102 ,  104  about the eye block  106 . In this way, a rotary input provided by an input shaft  404  may be converted and supplied by the gear box  402  to the jack screw  400 . 
       FIG. 5  illustrates an isometric view of a lifting bracket assembly  500  including the jack screw connector  100 . In this embodiment, the jack screw connector  100  is supported and carried by a base frame  502  via the gear box  402 . The base frame  502  further supports a drive motor  504  mechanically coupled to the input shaft  404  via a gear head  506 . The gear head  506  may be any known reduction gear, transmission or other mechanism coupling device. The jack screw connector  100  further cooperates with a lifting bracket  508  via the jack screw  400 . In particular, a jack nut  510  cooperates with the lifting bracket  508  to rotatably secure the jack screw  400 . The lifting bracket  508  may, in turn, be pinned or otherwise fixedly secured to a guide tube  512 . The guide tube  512  is received and guided by a guide bracket  514  secured to the base frame  502 . The guide tube  512  is further secured via a pin  518  to and configured to lift a rail beam  516 . For example, the guide bracket  514  may carry a key  520  sized to slideably cooperate with a keyway  522  formed in the guide tube  512 . In this way, alignment between the guide bracket  514  and the guide tube  512  may be maintained. The rail beam  516  may configured to support and carry a rail car (not shown) as it is lifted or lowered in the directions indicated by the arrow B. 
     The lifting bracket assembly  500  shown in  FIG. 5  utilizes a pair of guide tubes  512  in one embodiment. The illustrated two-guide post lifting bracket assembly  500  provides a compact design and a limited number of components. Alternatively, another embodiment may include four-guide post lifting bracket assembly (not shown) may provide for increased stability over the two-guide post lifting bracket assembly  500  while being configured to lift and support a greater load. 
       FIGS. 6 to 10  illustrate step by step assembly drawings for the lifting bracket assembly  500 .  FIG. 6  illustrates the base frame  502  (including the drive motor  504  and gear head  506 ) mounted to a test stand  600 . In another embodiment, the test stand  600  may be replaced by working surfaces  602 ,  602 ′ defined adjacent to a trench or circular caissons  604  dug into, for example, a rail car service facility. The base frame  502  may be positioned across the trench  604  and supported by the working surfaces  602 , 602 ′.  FIG. 7  illustrates the jack screw  400  aligned for coupling to the gear box  402  via the jack screw connector  100 .  FIG. 8  illustrates the jack screw  400  aligned for securing to the lifting bracket  508  via the jack nut  510 . The lifting bracket  508 , in this exemplary embodiment, is aligned to receive the guide tube  512 . The guide tube  512  is further aligned with the lifting bracket  508  utilizing the guide bracket  514  carried by the base frame  502 . When the guide tube  512  engages and cooperates with the lifting bracket  508  (see  FIG. 8 ), the pin  518  may secure the two components together. The guide tube  512 , when aligned with lifting bracket  508  via the guide bracket  514 , may further align with the rail beam  516 .  FIG. 9  illustrates the guide tube  512  secured or coupled to the rail beam  516  utilizing fasteners or bolts C. 
       FIG. 11  illustrates an exploded perspective view of the lifting bracket  508  aligned with, and configured to engage, the jack screw  400  and the guide tube  512 . The lifting bracket  508  may be a solid welded structure configured to support and receive the jack screw  400 . The jack nut  510  may further cooperate with a thrust bearing  1100  and a follower nut  1102  to allow the jack screw  400  to rotate freely relative to the lifting bracket  508 . The pin  518  may secure the guide tube  512  to the lifting bracket  508  utilizing one or more cotter pins D. 
     In operation, the motor  504  may cause the gear box  402  to rotate jack screw  400 . The jack screw  400  may, in turn, rotate with respect to the lifting bracket  508 . The lifting bracket  508  rides along the jack screw  400  in the direction indicated by the arrow B in  FIG. 5 . Because the lifting bracket  508  and the guide tube  512  are fixedly attached to each other, the movement of the lifting bracket  508  along the jack screw  400  will also cause the guide tube  512  to move in the direction indicated by the arrow B. The guide tube  512  engages and supports the beam rail  516  to raise or lower a rail car supported thereon. 
     In another embodiment, the lifting bracket assembly  500  may include one or more limit switches  524  configured to detect and communicate the position of the assembly  500 . In yet another embodiment, a limit switch may be affixed to, for example, the base frame  502  via a wire. The wire may be part of spring loaded mechanism configured to physically and/or mechanically link base frame  502  to the lifting bracket  508 . The wire or lanyard may be kept under constant tension by the spring loaded mechanism and the limit switch may be configured to detect the wire itself or a flag attached thereto. In normal operation, the limit switch may detect and verify the presence of the wire or flag. In the event of a failure such as, for example, a break in one of the jack screws  400 , the lifting bracket  508  would move freely relative to the frame base  502 . The uncontrolled or free movement would, in turn, separate the wire causing the limit switch to change state. The change in state may be utilized to stop and/or shut down the lifting bracket assembly  500 . 
     It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims