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Title: Scale employing wheatstone-type bridges and strain gages
Claims: I claim: 1. A scale, comprising: (a) a platform and means supporting said platform including load measuring means that includes eight strain gages in which four gages are under tension and four gages are under compression responsive to load applied to said platform, (b) two electrical Wheatstone bridges each of the type having four resistors, and said eight strain gages forming said resistors for said bridges whereby all of said resistors are active, said bridges having a joint voltage output signal proportional to said load, said two bridges forming the sole electrical Wheatstone bridge means to measure load of said scale, (c) said strain gages being arranged in pairs with one of the pair in tension and one in compression and there being torsion bar means associated with each pair of gages in which a torsion bar end portion is disposed in horizontally cantilevered position, said gages under compression being on one side of said torsion bar end portions and said gages under tension being on the opposite side of said torsion bar end portions, and (d) said load measuring means including a load transferring mounting associated with each torsion bar end portion that is adjustable therealong in scale calibration. 2. The subject matter of claim 1 in which each mounting is a ball having a support which is rotatable and has a ball rest eccentric relative to the axis of rotation, whereby adjustment of the load transferring mounting is achieved by rotation of said supports. 3. The subject matter of claim 2 in which each bridge includes a Wheatstone bridge, in which there are two horizontally-disposed, parallel, juxtaposed, spaced torsion bars, in which said platform is generally rectangular, in which said pair of gages have generally four corner locations relative to said platform, in which there is a base secured to the central portion of said torsion bars, and in which said platform rests on said balls. 4. A scale, comprising: (a) a plate-like generally rectangular platform, (b) a pair of horizontally-disposed, parallel, juxtaposed, spaced torsion bars located under opposite sides of said platform, (c) platform supporting means including means operative to apply platform load to the end portions of said torsion bars in four-corner disposition, (d) an upper and a lower strain gage on each torsion bar end portion for a total of eight strain gages and two Wheatstone type bridges using said strain gages for all resistors of said bridges whereby all bridge resistors are active and said two bridges form the sole electrical Wheatstone bridge means to measure load of said scale, (e) a base secured to the central portions of said torsion bars, and (f) said platform supporting means including said torsion bar end portions each having an upstanding, rotatably adjusted, threaded member secured therein with a head having a seat eccentrically located relative to the axis of rotation of said threaded member and a ball located on said ball whereby general leveling of said platform can be achieved by rotary full-turn adjustment of said threaded members and whereby scale calibration adjustment can be facilitated by less than full-turn adjustment of said threaded members thereby shifting the locations of said balls along said torsion bars. 5. The subject matter of claim 4 in which said base includes a rectangular frame and said torsion bars being juxtaposed to opposite sides of said frame, a channel receiving each torsion bar having a base interposed between said frame and the torsion bar, said channels having upper end portions of their legs cut away to avoid interfering with said threaded members and balls, and abutment means between the lower legs of said channels and torsion bar end portions to avoid damage to said torsion bars under excessive loads on said platforms. 6. The subject matter of claim 5 in which there is retainer means depending from said platform and engaging said base preventing lateral shifting of said platform horizontally of said base. 7. A scale, comprising: (a) a platform and means supporting said platform including load measuring means that includes strain gages, (b) electrical bridge means of the type having four resistors, said strain gages being included in the resistors of said electrical bridge means, said bridge means having a voltage output signal responsive to load, (c) said load measuring means including horizontally disposed torsion bars, and said torsion bars having said strain gages mounted thereon to measure strain in said torsion bars, and (d) said load measuring means including load transferring mountings associated with said torsion bars that are adjustable therealong in scale calibration. 8. A scale, comprising: (a) a plate-like generally rectangular platform, (b) a pair of horizontally-disposed, parallel, juxtaposed, spaced torsion bars located under opposite sides of said platform, (c) platform supporting means including means operative to apply platform load to the end portions of said torsion bars in four-corner disposition, (d) strain gages on said torsion bar end portions and Wheatstone type bridge means including said strain gages in the resistors of said bridge means, (e) a base secured to the central portions of said torsion bars, and (f) said platform supporting means including said torsion bar end portions each having an upstanding, rotatably adjusted, threaded member secured therein with a head having a seat eccentrically located relative to the axis of rotation of said threaded member and a ball located on said seat and a lower surface of said platform bearing on said ball whereby general leveling of said platform can be achieved by rotary full-turn adjustment of said threaded members and whereby scale calibration adjustment can be facilitated by less than full-turn adjustment of said threaded members thereby shifting the locations of said balls along said torsion bars. Other info: Inventors: Belcher, Claude A. (San Diego, CA, US) Application Number: 008401 Filing Date: 1979-02-01 Publication_date: 1980-09-23 Assignee: Primary Class(es): 177/211 177/255 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Miller, Jr., George H. Assistant Examiner: Attorney: Bowen; Duane C. |
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