Trailer weighing system

Abstract

A trailer includes: a chassis defining a pair of cross members, each of the pair of cross members fixed in position with respect to the chassis; a floating coupling apparatus coupled to the chassis between a first cross member and a second cross member of the pair of cross members, the floating coupling apparatus including: a fixed rail suspended between the first cross member and the second cross member; and a floating rail extending from a position proximate to the first cross member to a position proximate to the second cross member, the floating rail configured to move relative to the fixed rail; and a displacement-sensing device configured to sense a load acting on the displacement-sensing device.

That which is claimed is: 
     
         1 . A trailer comprising:
 a chassis defining a pair of cross members, each of the pair of cross members fixed in position with respect to the chassis;   a floating coupling apparatus coupled to the chassis between a first cross member and a second cross member of the pair of cross members, the floating coupling apparatus comprising:
 a fixed rail suspended between the first cross member and the second cross member; and 
 a floating rail extending from a position proximate to the first cross member to a position proximate to the second cross member, the floating rail configured to move relative to the fixed rail; and 
   a displacement-sensing device configured to sense a load acting on the displacement-sensing device.   
     
     
         2 . The trailer of  claim 1 , wherein the displacement-sensing device is positioned between the chassis and the floating coupling apparatus. 
     
     
         3 . The trailer of  claim 1 , wherein the displacement-sensing device comprises an air bag. 
     
     
         4 . The trailer of  claim 1 , wherein the displacement-sensing device comprises a switch configured to signal movement of the floating coupling apparatus relative to the chassis via a load indicator of the trailer. 
     
     
         5 . The trailer of  claim 4 , further comprising a load indicator in communication with the switch, the load indicator configured to signal that an output of the switch corresponding to a target trailer weight has been reached. 
     
     
         6 . The trailer of  claim 5 , wherein the load indicator comprises a load indicator light. 
     
     
         7 . The trailer of  claim 5 , further comprising a mode switch in communication with the load indicator, the mode switch configured to selectably supply power to the load indicator. 
     
     
         8 . The trailer of  claim 1 , wherein the floating rail is slidably attached to the fixed rail by a plurality of fasteners. 
     
     
         9 . A weighing system for a trailer, the system comprising:
 a floating coupling apparatus comprising:
 a fixed rail attached to a chassis of the trailer, the fixed rail comprising a substantially vertical portion resistant to deflection between a first end and a second end of the fixed rail; and 
 a floating rail slideably attached to the fixed rail, the floating rail comprising a substantially vertical portion resistant to deflection between a first end and a second end of the floating rail, the floating rail configured to move in a vertical direction with respect to the fixed rail; and 
   a displacement-sensing device coupled to the floating coupling apparatus and configured to sense movement of a portion of the floating coupling apparatus relative to the chassis.   
     
     
         10 . The system of  claim 9 , wherein the substantially vertical portion of a one of the fixed rail and the floating rail defines a slot, the system further comprising a fastener extending through the slot. 
     
     
         11 . The system of  claim 9 , wherein the floating coupling apparatus further comprises a fifth wheel plate. 
     
     
         12 . The system of  claim 11 , further comprising a kingpin attached to the fifth wheel plate of the floating coupling apparatus, a portion of the fifth wheel plate proximate to the kingpin fixed in position with respect to the floating rail. 
     
     
         13 . The system of  claim 9 , wherein the fixed rail is suspended between and attached to each of a first cross member and a second member of the chassis. 
     
     
         14 . The system of  claim 9 , wherein a one of the fixed rail and the floating rail is a beam, the fixed rail free to move relative to the floating rail when a load is applied to the chassis. 
     
     
         15 . A method of using a trailer, the method comprising:
 loading the trailer with a load, the trailer comprising:
 a chassis defining a pair of cross members; 
 a floating coupling apparatus coupled to the chassis between a first cross member and a second cross member of the pair of cross members, the floating coupling apparatus comprising:
 a fixed rail of the floating coupling apparatus suspended between and attached to each of the first cross member and the second cross member of the chassis; and 
 a floating rail of the floating coupling apparatus extending from a position proximate to the first cross member to a position proximate to the second cross member, the floating rail configured to move relative to the fixed rail, the floating rail positioned adjacent to the fixed rail; and 
 
 a displacement-sensing device coupled to the floating coupling apparatus; 
   measuring displacement of a portion of the floating coupling apparatus relative to the chassis with the displacement-sensing device; and   signaling when the displacement of the portion of the floating coupling apparatus corresponds with a target trailer weight.   
     
     
         16 . The method of  claim 15 , wherein each of the pair of cross members comprises a substantially vertical portion resistant to deflection between a first end and a second end of the respective cross member. 
     
     
         17 . The method of  claim 15 , further comprising signaling when the trailer weight has reached an overloaded condition. 
     
     
         18 . The method of  claim 15 , wherein the displacement-sensing device comprises an air bag, the method further comprising compressing the air bag by movement of the fixed rail with respect to the floating rail. 
     
     
         19 . The method of  claim 15 , wherein the displacement-sensing device comprises a switch and wherein measuring the displacement of a portion of the floating coupling apparatus relative to the chassis comprises measuring the output of the switch. 
     
     
         20 . The method of  claim 15 , further comprising:
 determining the target trailer weight;   weighing the trailer with an independent scale after loading the trailer with a load; and   adjusting a switch of the trailer to activate at the target trailer weight.