Abstract:
A drive-through work station with power operated tarping equipment is provided to efficiently and safely apply tarpaulin covers to payloads on flatbed highway trailers. The work station may include a work platform at one or both sides of the trailer being tarped.

Description:
TECHNICAL FIELD 
     This invention relates to placement of a tarpaulin cover over a payload on a flatbed trailer of the type towed on highways by an appropriately equipped tow truck or tractor. 
     BACKGROUND OF THE INVENTION 
     Many payloads transported on flatbed trailers need to be covered to protect the load from the sun, dust, rain, sleet, snow and the like. Heretofore it has been a common practice to protect vulnerable payloads with a large tarpaulin cover which is relatively heavy. Because of the weight of the tarpaulin cover, the services of several workmen are needed to lift and place the cover on the payload. Typical trailer tarping operations are labor intensive and time-consuming. 
     INFORMATION DISCLOSURE STATEMENT 
     Flatbed trailers are typically “tarped” by a substantial number of workmen lifting and tugging a heavy tarpaulin cover over the payload on the flatbed trailer. The tarpaulin cover is heavy and thus requires a considerable number of workmen. The proper number of workman are not always available at the time needed and thus time is wasted waiting for the required number. At some locations workmen are drawn from other work projects, thus causing undesirable interruptions in those projects. Manually moving the tarpaulin cover into a cargo covering position on a flatbed trailer is a difficult job requiring considerable strength and not all workmen are capable of such work or agreeable to engage in such work. 
     Heretofore others have provided protective covers for various cargo carrying vehicles. U.S. Pat. No. 2,070,586, issued on Feb. 16, 1937 to B. F. Fitch on a Freight container, discloses a freight container having a roof of corrugated metal sheets which may be lifted by a hoist hook. 
     U.S. Pat. No. 3,994,240, issued Nov. 30, 1976, to R. L. Berg et al. on a Coil Car Cover, describes a light weight removable cover for railroad coil cars which is made of fiberglass reinforced plastic and which includes a lifting cage engageable by the lift hook of a crane. 
     U.S. Pat. No. 4,050,734 issued Sep. 27, 1977 to D. B. Richard on a Roll-up Truck Cover Assembly, shows a flexible top cover for a dump truck. The flexible cover is wound up on a spring biased take-up roll carried on support arms pivoted by fluid operated cylinders. 
     U.S. Pat. No. 5,036,775, issued Aug. 6, 1991, to E. D. Snead on a Covered Gondola Car, shows gondola cars covered by rigid covers made of fiberglass which can be removed by a tractor-shovel. 
     U.S. Pat. No. 5,054,402 issued Oct. 8, 1991, to G. W. Brassell on a Removable Cover for Gondola Cars with Lightweight Composite Panel Construction, discloses removable cover panels having a plastic foam core sandwiched between metal sheets. The cover is removable by connecting a hoist hood to a lift line. 
     U.S. Pat. No. 5,682,823, issued Nov. 4, 1997, to E. L. Tihansky et al. on a Removable Insulated Cover and Method of Transporting Hot Oversized Steel Ingots, shows a rigid protective housing for a ingot placed on a railroad car by a lifting device. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is a primary object of this invention to provide a drive-through work station for efficiently installing a tarpaulin cover to a payload on a flatbed highway trailer It is a further object to provide a work station for installing a tarpaulin cover to a flatbed highway trailer which required less manpower than heretofore required. Another object of this invention is the provision of a work station to install a tarpaulin cover to the payload on a flatbed trailer in less time than heretofore required. A further object of the invention is to enhance worker safety, as for instance, by decreasing the chance of workers falling off the trailer during a tarping operation and by providing safe worker movement to and from the flatbed trailer. 
     The work station of the present invention utilizes a power operated traveling hoist for lifting and moving a tarpaulin cover to its cargo covering position with minimal manpower and in much less time than previously required. 
     In a preferred embodiment of the invention, one end of the tarpaulin cover is releaseably attached to a hanger on the end of a hoist line or chain of a power operated winch. The power operated winch is mounted on a wheeled carriage supported on an overhead track running lengthwise above the trailer. After the tarpaulin end is raised by the power winch, the carriage is power driven along the support track thereby pulling the tarpaulin cover over the payload on the trailer The towed end of the tarpaulin cover is lowered and disconnected from the hanger. Then the tarpaulin cover is secured to the trailer. 
     In order to facilitate the operation of the work station a walkway or work platform is preferably provided at one or both lateral sides of the trailer. The work platform may be at the height of the flatbed trailer for trailers transporting loads of low elevation, or it may be at an elevated height for trailers carrying high loads. The work performed affords safe movement of workers to and from the flatbed trailers, and positions for handling and fastening the tarpaulin to the trailer or the cargo. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various embodiments of the invention are illustrated by the drawings, in which: 
     FIG. 1 is a top view of a trailer tarping work station; 
     FIG. 2 is a side view of the work station shown in FIG. 1; 
     FIG. 3 is an end view of the work station shown in FIG. 2; 
     FIG. 4 is a side view showing the traveling hoist of the work station; 
     FIG. 5 is an end view of the traveling hoist shown in FIG. 4; 
     FIG. 6 is a side view of the work station showing the winch line lowered and a hanger connected to a tarpaulin cover; 
     FIG. 7 is a side view of the work station showing the tarpaulin cover being moved lengthwise over the payload on the trailer; 
     FIG. 8 is a top view of a workstation which includes a work platform; 
     FIG. 9 is a side view of the work station shown in FIG. 8; 
     FIG. 10 is an end view of the work station shown in FIG. 9; 
     FIG. 11 is a side view of a workstation having an elevated work platform; 
     FIG. 12 is an end view of the work station shown in FIG. 11; 
     FIG. 13 is a top view of a workstation having work platforms at both lateral sides of the trailer; 
     FIG. 14 is a side view of the work station shown in FIG. 13; 
     FIG. 15 is an end view of the work station shown in FIG. 14; 
     FIG. 16 is a side view of a work station having an elevated work platform at each of the lateral sides of the trailer being tarped; 
     FIG. 17 is an end view of the work station shown in FIG. 16; 
     FIG. 18 is an end view of a work station having work platforms at opposite lateral sides of the trailer which are supported on wheels permitting lateral movement of the platforms relative to the trailer, and 
     FIG. 19 is a partial side view of one of the wheeled platforms shown in FIG.  18 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1,  2  and  3 , a flatbed trailer  22  with a payload  23  has been disconnected from its towing tractor. The front end of the trailer is supported on a swingdown support  24  and the rear of the trailer is supported by its tandem wheels  26 . The trailer  22  is parked at a tarping work station which includes an overhead track  28  in the form on a wide flange I beam, or H beam. The track  28  is rigidly secured to parallel support arms  30  extending horizontally from the top of a pair of vertical support poles  32  spaced from one another in the longitudinal direction of the trailer  22 . The support poles  22  include pads at their bottoms which are rigidly bolted to studs extending upwardly from buried concrete bases. A traveling hoist  34 , such as a commercially available hoist model YEL 1/4-MT 16S1 sold by YALE of Forest City, Ark., is mounted on the overhead track  28  and includes a winch  38  supporting a tarpaulin hanger  36 . 
     The travel of the hoist  34  on the track  28  and the raising and lowering of the tarpaulin hanger  36  is controlled by a push button controller  33  on the end of are tractable electric cable  35 . Although the trailer ( 22 ) is shown disconnected from its tow tractor, the work station is designed as a drive-through facility and in normal operation the tow tractor is not disconnected from the trailer and the truck and trailer remain at the station only long enough for tarping of the trailer. 
     Referring to FIGS. 4 and 5, the traveling hoist  34  includes the winch  38  powered by a reversible electric motor  40 . The winch  38  is supported on a traveling carriage  42  having a pair of drive wheels  44  at each of the opposite lateral sides of the web of the track  28 , the wheels  44  engaging the top sides of the bottom flanges of the I beam track  28 . The wheels  44  of the carriage are driven by a reversible electric motor  46  to move the traveling hoist along the track  28 . The electric winch  38  includes a hoist line  56  with a hoist hook  56  connected to an eye  58  on the tarpaulin hanger  36 . The hanger  36  has a pair of spaced hooks  62  on a cross rod  60  which are adapted for releasable connection to tarpaulin covers. 
     Referring to FIG. 6, the winch cable has been lowered and the hooks  62  of the hanger  36  are connected to one longitudinal end of a tarpaulin cover  64 . The winch has raised and pulled the tarpaulin to near the rear end of the payload  23 . FIG. 7 shows the tarpaulin end raised above the payload  23  and the traveling hoist ( 34 ) has been power driven to a mid position relative to the payload  23  on the trailer  22 . The tarpaulin cover  64  has been moved forward to cover about one half of the payload  23 . To complete the covering operation, carriage  42  will be driven forward on the track  28  to bring the tarpaulin cover  64  end to near the front end of the payload  23 . The tarpaulin cover  64  is then disconnected from the hanger  36  and workmen secure the cover to the trailer  22  and/or the payload  23 . 
     Electric power is supplied to the electric motors  40 ,  46  by sliding contact rails, not shown, carried by the track  28 . The reversible electric motors  40 ,  46  are controlled by the hand held controller  33  which has manually operated push buttons for fore and aft travel of the hoist  34  and raising and lowering of hoist line  56  and hanger  36 . 
     The work station shown in FIGS. 8,  9  and  10  includes a walkway or work platform  70  at one lateral side of the trailer  22 . The work platform  70  is preferably as long as the trailer  22  and includes a ladder or stair case  72  at one end together with appropriate guard rails  74 . There are no guard rails on the side of the walkway that is adjacent the trailer  22 , thus permitting worker access to the trailer  22  and its payload  23 . The work platform  70  is supported by legs  76  at the height of the floor of flatbed trailer and the platform  70  may be secured to the track support posts  32 . The work platform  70  facilitates the tarping of a trailer by making it easier and quicker for workmen to assist in completing the load covering job including moving into position to fasten down the tarpaulin cover. Also, by standing on the work platform  70  the worker with the hoist controller  33  is in a better position to oversee the covering operation and to properly control the traveling hoist  34 . 
     FIGS. 11 and 12 show a work station in which the work platform  80  is elevated to near the top of the payload  23  on the trailer  22 . This construction is desirable for tarping payloads which have considerable height. 
     FIGS. 13,  14  and  15  illustrate a work station having a first work platform  70  on one lateral side of the trailer  22  and a second work platform  84  at the opposite lateral side of the trailer  22  being tarped. This allows additional workmen to assist in the tarpaulin cover applying operation thereby speeding up the tarping procedure. Also, an irregular configuration of the payload may make it desirable to have workman at both sides of the trailer and in positions to properly place a tarpaulin cover on the payload. 
     FIGS. 16 and 17 show a work station with elevated work platforms  86 ,  88  at opposite sides of the trailer being tarped. Workmen on these elevated platforms can prevent the tarpaulin being dragged across payload items having sharp corners or edges. This work station design is desirable for high payloads or payloads having tarpaulin covers applied only to their tops. 
     FIGS. 18 and 19 illustrate a work station having work platforms  90 ,  92  at opposite sides of the trailer  22  being tarped, which are mounted on rollers or wheels  94  supported on laterally extending tracks  96 ,  98  having stops or abutments  100  at their opposite ends. By rolling the platforms  90 ,  92  away from one another the truck operator is given additional room to drive the truck and trailer into the tarping station and each platform can then be rolled into the desired position adjacent the trailer for the tarping of the trailer. This construction prevents accidental damage to the work station by the truck or trailer when moved into the tarping station. Also, the work platform  90  can be rolled away from the tractor/trailer if the truck driver needs to inspect the tires or other parts of the trailer prior to moving the trailer out of the work station. 
     In order to avoid unnecessary repetition, the controller  33  and its electric cable  35  are not illustrated in FIGS. 8-18; however, it is to be understood that these components are present in an operative construction of this invention.