Trailer tongue weight measurement system

Abstract

A trailer tongue weight measurement system is provided to ensure proper loading and safe handling of a trailer being towed by a vehicle. The weight measurement system includes a two part or split housing having a operating shaft, a spring and a scale. The weight measurement system may be incorporated into the trailer tongue, the tongue jack, or the hitch. Deflection of the spring in response to a load on the trailer is converted to a weight measurement that may be read on a calibrated scale.

1 . A trailer weight measurement system comprising:
 a split housing, wherein one part of the split housing may move relative to another part of the split housing;   a shaft rotatably disposed within the housing, the shaft comprising:
 a non-threaded portion; 
 a distal end of the non-threaded portion of the shaft extending through a shaft opening in one part of the split housing; 
 a threaded portion, the threaded portion being threaded into a threaded hole in the other part of the split housing; 
 a shoulder separating the non-threaded portion and the threaded portion of the shaft; 
   a spring located within the split housing and concentrically around the shaft between the shaft shoulder and an inside surface of one part of the split housing;   a handle located external to the split housing and connected to the distal end of the shaft; and   a scale having a zero point and a series of indicators corresponding to a weight being measured by the weight measurement system.   
     
     
         2 . The trailer weight measurement system of  claim 1 , wherein the split housing further comprises a tube-like housing comprising a main housing and a jack housing, the jack housing slidably disposed within the main housing and extending through an open bottom end of the main housing. 
     
     
         3 . The trailer weight measurement system of  claim 2 , wherein:
 the main housing further comprising:
 a top end having the shaft opening; 
 the open bottom end; 
 a side wall extending between the top end and the open bottom end; 
   the jack housing further comprising:
 a top end; 
 the threaded hole in a center of the top end; 
 a bottom end; 
 a foot plate at the bottom end of the jack housing for engaging a support surface; 
   the shaft further comprising:
 the distal end of the non-threaded portion of the shaft extending through the shaft opening in the top end of the main housing; 
 the threaded portion being threaded into the threaded hole in the top end of the jack housing; 
   a thrust bearing disposed concentrically about the non-threaded portion of the shaft, a first side of the thrust bearing contacting the shaft shoulder;   the spring disposed concentrically about the non-threaded portion of the shaft, a first end of the spring contacting a second side of the thrust bearing, and a second end of the spring contacting an inside surface of the top end of the main housing, the spring acting to urge the main housing and the jack housing apart; and   the scale located on the non-threaded portion of the shaft proximate the shaft opening, the scale having a zero point and a series of indicators corresponding to a weight being measured by the weight measurement system.   
     
     
         4 . The trailer weight measurement system of  claim 3 , wherein the weight measurement system may be calibrated so that the zero point of the scale is at the shaft opening with no load on the system, and wherein the shaft moves upward out through the shaft opening as a load is applied to the system and the spring compresses thereby revealing the series of indicators on the scale on the shaft. 
     
     
         5 . The trailer weight measurement system of  claim 2 , wherein:
 the main housing further comprising:
 a top end having the shaft opening; 
 the open bottom end; 
 a side wall extending between the top end and the open bottom end; 
   the jack housing further comprising:
 a top end; 
 the threaded hole in a center of the top end; 
 a bottom end; 
 a foot plate at the bottom end of the jack housing for engaging a support surface; 
   a gear housing slidably disposed over the top end of the main housing and the distal end of the shaft, the gear housing comprising:
 a right angle gear set connected to the non-threaded portion of the shaft extending through the shaft opening, the gear set for transitioning the shaft output 90 degrees; 
 an upper portion of the gear housing extending above the main housing and enclosing the gear set; 
 a lower portion of the gear housing extending over and about an upper portion of the main housing to a lower edge; 
   the shaft further comprising:
 the distal end of the non-threaded portion of the shaft extending through the shaft opening in the top end of the main housing; 
 the threaded portion being threaded into the threaded hole in the top end of the jack housing; 
   a thrust bearing disposed concentrically about the non-threaded portion of the shaft, a first side of the thrust bearing contacting the shaft shoulder;   the spring disposed concentrically about the non-threaded portion of the shaft, a first end of the spring contacting a second side of the thrust bearing, and a second end of the spring contacting an inside surface of the top end of the main housing, the spring acting to urge the main housing and the jack housing apart; and   the scale located on upper portion of the main housing, the scale having a zero point and a series of indicators corresponding to a weight being measured by the weight measurement system.   
     
     
         6 . The trailer weight measurement system of  claim 5 , wherein the weight measurement system may be calibrated so that the zero point of the scale is at the lower edge of the gear housing with no load on the system, and wherein the gear housing moves upward with the shaft as a load is applied to the system and the spring compresses thereby revealing the series of indicators on the scale on the main housing. 
     
     
         7 . The trailer weight measurement system of  claim 2 , further comprising a flange plate extending from the main housing and having one or more holes for connecting the trailer weight measurement system to a coupler of a trailer. 
     
     
         8 . The trailer weight measurement system of  claim 2 , further comprising a pin for securing the shaft in place relative to the main housing, the pin holding the shaft, spring, thrust bearing, and jack housing from falling out the bottom of the main housing. 
     
     
         9 . The trailer weight measurement system of  claim 2 , further comprising a crank shaft connected to the non-threaded portion of the shaft extending through the opening in the top end of the main housing, wherein rotation of the crank shaft causes rotation of the shaft and sliding movement of the jack housing relative to the main housing. 
     
     
         10 . The trailer weight measurement system of  claim 2 , further comprising a tongue and groove formed between the main housing and the jack housing, the tongue and groove constraining rotational movement between the main housing and the jack housing. 
     
     
         11 . The trailer weight measurement system of  claim 2 , further comprising a gage read out for amplifying the spring deflection to make it easier to read. 
     
     
         12 . The trailer weight measurement system of  claim 11 , wherein the gage read out further comprises:
 a gage housing disposed over the top end of the main housing, wherein the shaft extends through the gage housing;   a circular gear rack formed on the portion of the shaft extending through the gage housing;   a pinion gear engaged with the circular gear rack;   a shaft extending from the pinion gear through an opening in the gage housing to an exterior of the gage housing; and   an indicator needle connected to the shaft and extending over the scale, the scale being formed on an exterior surface of the gage housing.   
     
     
         13 . The trailer weight measurement system of  claim 2 , wherein the weight measurement system is retrofit into an existing trailer tongue jack by replacing at least the shaft and adding the spring. 
     
     
         14 . The trailer weight measurement system of  claim 2 , wherein the weight measurement system is formed integral with a new trailer tongue jack. 
     
     
         15 . The trailer weight measurement system of  claim 1 , wherein the spring further comprises a coil spring. 
     
     
         16 . A trailer weight measurement system comprising:
 a main housing comprising:
 a top end having a shaft opening; 
 an open bottom end; and 
 a side wall extending between the top end and the open bottom end; 
   a jack housing slidably disposed within the main housing and extending from the open bottom end, the jack housing comprising:
 a top end having a threaded hole; 
 a foot plate at a bottom end of the jack housing for engaging a support surface; 
 a side wall extending between the top end of the jack housing and the foot plate; 
   a shaft rotatably disposed within the main housing, the shaft comprising:
 a non-threaded upper portion; 
 a distal end of the non-threaded upper portion of the shaft extending through the shaft opening in the top end of the main housing; 
 a threaded lower portion, the threaded lower portion being threaded into the threaded hole in the top end of the jack housing; 
   a thrust bearing disposed concentric about the non-threaded portion of the shaft, a first side of the thrust bearing contacting the threaded portion;   a spring disposed concentrically about the non-threaded portion of the shaft, a first end of the spring contacting a second side of the thrust bearing, and a second end of the spring contacting the main housing; and   
       a scale having a series of indicators corresponding to a weight being measured by the weight measurement system, wherein a deflection of the spring and movement of the shaft corresponds to a weight being measured that is displayed on the scale.