Abstract:
A movable bed frame for installation in a conventional trailer and which has a unique counterbalance system for raising the bed frame to a horizontal up or storage position and for lowering the bed frame in a horizontal down position. The counterbalance system is produced by pressurized gas pistons secured to the bed frame and to side walls of the trailer which balances the bed frame so well that a child eight years old can raise and lower the bed frame.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a bed frame for installation in a conventional trailer and having a unique counterbalance means for raising and lowering the bed frame. 
     There is a need for a trailer bed frame which can be installed inside a conventional trailer with or without a mattress and easily raised to a horizontal up or storage position and easily lowered to a horizontal down position when used for sleeping persons. There is also a need for simple and easy means for counterbalancing the bed frame, so that even an eight year old child will be able to raise or lower the bed frame and for the means to be made up of relatively simple and inexpensive component parts readily available. Another need is for the bed frame to be adjustable in size so that mattresses ranging from twin size to king size may be accommodated without adversely affecting the operation of the bed frame. 
     Applicant is unaware of any prior art providing for a bed frame which can be installed in a conventional trailer and which is provided with counterbalance means allowing a child to raise or lower the bed frame and is made from readily available component parts and accepts a range of mattresses from twin size to king size. 
     OBJECTS OF THE INVENTION 
     It is, therefore, an object of the invention to provide a bed frame for installation in a conventional trailer and which can be easily raised to a horizontal up or storage position and easily lowered to a horizontal down or sleeping position. 
     Another object of the invention is to provide a bed frame for installation in a conventional trailer and which has counterbalance means for easy movement of the bed frame in an up or down direction. 
     A further object of the invention is to provide a bed frame for installation in a conventional trailer which has counterbalance means that allows an eight year old child to move the bed frame in an up or down position. 
     A still further object of the invention is to provide a bed frame for installation in a conventional trailer and which can be made from readily available component parts. 
     A yet further object of the invention is to provide a bed frame for installation in a conventional trailer and which accepts a range of mattresses from twin size to king size due to adjustment of the size of the bed frame and due to varying the counterbalance means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view illustrating an embodiment of the invention in its horizontal up or storage position and with dotted lines in a horizontal down position in a conventional trailer. 
     FIG. 2 is a side elevational view illustrating an embodiment of the invention in its horizontal up or storage position against a broken away portion of the inside back wall of a trailer. 
     FIG. 3 is a side elevational view illustrating an embodiment of the invention in a transitional position inside a trailer having its back wall broken away. 
     FIG. 4 is a side elevational view illustrating an embodiment of the invention in its horizontal down position inside a trailer. 
     FIG. 5 is a front cross sectional view taken along line  5 — 5  of FIG. 2 of an embodiment of the invention and illustrates the right pivot and right anchor points of the counterbalance means. 
     FIG. 6 is a cross sectional view taken along line  6 — 6  of FIG.  2  and illustrates the left stop and left rear guide of an embodiment of the invention. 
     FIG. 7 is a perspective view of an embodiment of the invention in its horizontal up position for storage and shows a mattress therein with dotted lines. 
     FIG. 8 is a side elevational view illustrating another embodiment of the invention in its horizontal up or storage position and with dotted lines in a down position in a conventional trailer. 
     FIG. 9 is a side elevational view illustrating another embodiment of the invention in its horizontal up or storage position against a broken away portion of the inside back wall of a trailer. 
     FIG. 10 is a side elevational view illustrating another embodiment of the invention in a transitional position inside a trailer having its back wall broken away. 
     FIG. 11 is a side elevational view illustrating another embodiment of the invention in a horizontal down position inside a trailer. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     A conventional trailer  10  has installed in it the trailer bed frame  12 , which has a side board member  14  and its other side open to receive a mattress or storage items. Trailer bed frame  12  has a bottom board member  16 , a rear board member  18 , and a front board member  20 . These component parts of the bed frame  12  are solidly joined together by any conventional means and can be made from any suitable wood material, such as plywood, that is sufficiently strong to support the weight of a mattress and persons sleeping on the mattress. 
     The front ends of rear board member  18  and front board member  20  are formed into support members  21  for support of the bed frame  12  in its up or down position. 
     The bed frame  12  is provided with counterbalance means comprising a set of four pressurized gas counterbalance pistons  22 , of which two are pivotally secured at their top ends to rear board member  18  and two are pivotally secured at their top ends to front board member  20  of the bed frame  12 . Each counterbalance piston  22  is pivotally secured at its bottom end to the side walls of trailer  10 . All the counterbalance pistons  22  push toward the rear wall of trailer  10 . 
     The gas pressure in the counterbalance pistons  22  may be varied as needed to accommodate various weights of bedframes  12 . Thus, for bed frames weighing from 80 to 100 pounds, counterbalance pistons having gas pressure of 100 pounds may be used. For bed frames weighing from 100 to 120 pounds, counterbalance pistons having gas pressure of 120 pounds may be used. For bed frames weighing from 110 to 130 pounds, counterbalance pistons having gas pressure of 130 pounds may be used. For bed frames weighing from 120 to 140 pounds, counterbalance pistons having gas pressure of 140 pounds may be used. 
     Further variations in the counterbalance means can be made by relocating the position of the counterbalance pistons  22 . 
     For a queen size bed frame  12  having an overall length of about 71 inches, the counterbalance pistons  22  are located as follows: 
     The bottom ends of counterbalance pistons  22  are located about 61¾ inches above the floor of the trailer  10 . The two counterbalance pistons  22  of rear board member  18  and front board member  20  closest to the rear wall of trailer  10  may be referred to as rear counterbalance pistons  22  and their top ends are pivotally mounted on bed frame  12  at a position about 9 inches from the rear wall of the trailer  10  as shown in FIG.  3 . The other two counterbalance pistons  22  respectively of rear board member  10  and front board member  20  may be referred to as front counterbalance pistons  22  and their top ends are pivotally mounted at a position on bed frame  12  about 46 inches from the top ends of the two rear counterbalance pistons  22 . 
     The bottom ends of the two rear counterbalance pistons  22  are respectively pivotally mounted on opposite side walls of the trailer  10  at a position about 25½ inches from the rear wall of the trailer  10 . The bottom ends of the two front counterbalance pistons  22  are respectively pivotally mounted on opposite side walls of the trailer  10  at a location about 71⅝ inches from the rear wall of the trailer  10 . 
     The counterbalance pistons  22  have an extended length of about 29¾ inches and a closed or collapsed length of about 17¼ inches. A suitable counterbalance piston is Model No. C16-19974-16-4-365-325-A11-B11-400 N produced by Suspa, Inc. of Grand Rapids, Mich. 
     For different sizes of bed frames, the above locations can be varied as needed, so long as the counterbalance pistons  22  are kept in parallel relationship to each other. 
     Roller members  24  are attached at the top of each end of side board member  14 . 
     Upper ledge members  26  are located about 6½ inches below the ceiling of the trailer  10  and are attached on each opposite side wall of the trailer  10  to support the support members  21  of bed frame  12  in its up or storage position. 
     Lower ledge members  28  are located about 34¼ inches below the ceiling of trailer  10  and attached on each opposite side wall of trailer  10  to support the support members  21  of bed frame  12  in its down or sleeping position. 
     For easy movement of bed frame  12  up or down, roller members  24  bear against each end member  30  of the back wall of trailer  10 . 
     In a second embodiment of the invention as shown in FIGS. 8 through 11, each end of the rear wall of trailer  10  has track guide means  31  to guide roller members  24  when bed frame  12  is moved. 
     Lower stop members  32  are located 34¼ inches below the ceiling of the trailer  10  and attached at each end of the back wall of the trailer  10  to limit downward travel of the bed frame  12 . 
     Strap means  34  is attached to the underside of bottom board member  16  to begin operation of the bed frame  12 . 
     In the second embodiment of the invention shown in FIGS. 8 through 11, the component parts and location and arrangement of counterbalance pistons  22  have not been changed except for the location of the bottom ends of front counterbalance pistons  22 . These bottom ends of front counterbalance pistons  22  are respectively pivotally mounted on opposite side walls of the trailer  10  at a location about 37 inches from the rear wall of the trailer  10 , thereby maintaining a distance from the bottom ends of rear counterbalance pistons  22  of about 12 inches. 
     As in the first embodiment, the second embodiment of the invention has two rear counterbalance pistons  22  which push toward the back wall of the trailer  10 . However, the second embodiment has two front counterbalance pistons  22  which push to the front due to the new location of their bottom ends, which achieves the same result of offsetting the weight of the bed frame  12  and any mattress in it as achieved by the first embodiment of the invention. 
     In operation, when the bed frame  12  has been installed in the trailer  10 , and placed in the horizontal up or storage position, a pull on strap means  34  will lift the right end of bed frame  12  off from upper ledge members  26  and bed frame  12  will assume the position shown in FIG.  3 . The counterbalancing effect of the counterbalance pistons  22  will require only a moderate pull on strap means  34  to begin the downward travel of bed frame  12 . Once the downward movement begins, the bed frame  12  will gently arrive and be stopped at lower stop members  32  and lower ledge members  28  in a horizontal position. A child of 8 years is able to accomplish the downward movement of the bed frame  12  due to the counterbalance means. 
     After use as desired in the down position, the bed frame  12  is pushed in an upwards direction. Again, the counterbalance means allows minimum force needed to begin the upwards movement, which an eight year old child can provide. The bed frame  12  continues in its upwards travel which is limited by the extended counterbalance pistons  22  to a horizontal position about 6½ inches below the ceiling of the trailer  10 . The bed frame then is supported in its horizontal up or storage position by support members  21  resting on upper ledge members  26  and by the extended counterbalance pistons  22 . 
     Bed frame  12  can be modified in size to receive mattresses of various sizes, and the bed frame  12  modifications range from twin size widths of 30 to 34 inches, double size widths of 48 to 54 inches, queen size width of 60 inches, and king size widths of 72 to 80 inches. The length of bed frame  12  can range from 72 to 100 inches. However, the preferred length of bed frame  12  is 96 inches which is the current distance between side walls of trailer  10 . 
     The various locations of the counterbalance pistons  22  may be modified as needed for the various sizes of bed frame  12 . 
     The counterbalance pistons  22  are preferably pressurized with nitrogen gas. However, other suitable gasses may be used. Other types of suitable counterbalance means include hydraulic or mechanical pistons or extension arms having the requisite counterbalancing capacity. 
     Although I have described the invention in detail with reference to the accompanying drawings illustrating preferred embodiments of the invention, it is understood that numerous changes may be made in the details of construction and arrangement of parts without departing from the spirit and scope of the invention as hereinafter claimed.