Nova Patents
CA2020892C

Load cell mounting for rotational control

Abstract

Load cells incorporating rocker pin configured columnar centralstructures within a weighing system have the attribute of self-erecting uponbeing displaced from a vertical orientation due to dynamic transverseloading effects, as may be occasioned by vehicle movements onto a scale.The resultant transient vector forces thus developed have been observed tocause a rotational phenomenon in the rocker pin configured cells whichcauses unacceptable damage to the instrumentation control communicationcomponents of the load cell system. A mounting technique for such loadcells is developed wherein only these rotation inducing forces are restrained,while the vertical force vectors representing valid load data are maintainedin an unrestricted or uncompromised manner. In one aspect of theinvention, a hexagonal form of mounting between a rocker pin neck-contactsurface region and a corresponding receiver cavity achieves a fully pivotingand freely abutting contact geometry while effecting the noted restrictionof rotation. In another aspect, a resilient device such as spring is loadedduring restricted rotational movement of the load cell and released at thetermination of the transient rotational forces to return the load cells totheir initial orientation while the load cells remain under load inducedcompression.

Term

Term ended

Expired 11 July 2010, 16.2 years ago.

  1. Priority
  2. Filed
  3. Granted
  4. Expired
  5. Today

10 claims: 6 independent, 4 dependent

  1. 1
    THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:1. Weighing apparatus comprising a base (22), a load receiving surface (12), at least one self-erecting rocker pin load cell (38) having a vertically aligned longitudinal axis and upper and lower end portions formed with upper (86) and lower (106) contact surfaces positioned between said base (22) and said load receiving surface, respectively, for freely pivotal supporting contact with said load receiving surface, at least one of said upper and lower end portions being received in a rocker pin receiving cavity (100) having a peripheral side wall (108) of a receiver (52), said load cell being subject to both vertical and temporary transverse force vectors creating transient rotational force vectors urging said rocker pin (40) to rotate about said longitudinal axis, said load cell further comprising restrainer means for providing a rotationally stable reference isolated from said rocker pin, and rotation limit means in contact with said load cell (38) and coupled with said restrainer means so as to restrict said rotation of said load cell (38) within predetermined limits by counteracting only said rotational force vectors while not affecting the reaction of said load cell to said vertical force vector and not substantially affecting said freely pivotal supporting contact, characterized in that said restrainer means is formed by said receiver (52) having a lateral portion (110a 110f) of the peripheral side wall (108) formed of non circular 16 configuration and extent and configured for effecting freely pivotal abutting support of said rocker pin load cell (38);and said rotation limit means is formed by the lower end portion of said rocker pin load cell received within said cavity (100) and having a peripherally disposed positioning surface with a noncircular portion (120a - 120f) corresponding with and of lesser extent than said lateral portion (110a - 110f).
  2. 4
    Weighing apparatus as claimed in any one of claims 1 to 3, in which said rocker pin non-circular portion (120a - 120f) is configured as a segment of a right cylinder.
  3. 5
    Weighing apparatus as claimed in any one of claims 1 to 3, in which said receiver cavity (100) is formed having six said peripheral side wall lateral portions (110a - 110f) of substantially linear configuration and of generally hexagonal profile;and said rocker pin non-circular portion (120a - 120f) is configured having a corresponding said hexagonal profile. 17
  4. 7
    Weighing apparatus comprising a base (22), a load receiving surface (12), at least one self-erecting rocker pin load cell (196) having a vertically aligned longitudinal axis and upper (86) and lower (106) contact surfaces positioned between said base (22) and said load receiving surface for freely pivotal supporting contact with said load receiving surface, said load cell being subject to both vertical and temporary transverse force vectors creating transient rotational force vectors urging said rocker pin (40) to rotate about said longitudinal axis, said load cell further comprising restrainer means for providing a rotationally stable reference isolated from said rocker pin, and rotation limit means in contact with said load cell (150) and coupled with said restrainer means so as to restrict said rotation of said load cell (196) within predetermined limits by counteracting only said rotational force vectors while not affecting the reaction of said 18 load cell to said vertical force vector and not substantially affecting said freely pivotal supporting contact, characterized in that said rotation limit means comprises spring means (210, 212) mounted between said restrainer means (200, 202) and said load cell (196) along an axis substantially transverse to said longitudinal axis for resiliently returning said load cell (196) to an initial position subsequent to the induced rotation thereof.
  5. 8
    Weighing apparatus comprising a base (22), a load receiving surface (12), at least one self-erecting rocker pin load cell (224) having a vertically aligned longitudinal axis and upper (86) and lower (106) contact surfaces positioned between said base (22) and said load receiving surface for freely pivotal supporting contact with said load receiving surface, said load cell being subject to both vertical and temporary transverse force vectors creating transient rotational force vectors urging said rocker pin (40) to rotate about said longitudinal axis, said load cell further comprising restrainer means for providing a rotationally stable reference isolated from said rocker pin, and rotation limit means in contact with said load cell (150) and coupled with said restrainer means so as to restrict said rotation of said load cell (224) within predetermined limits by counteracting only said rotational force vectors while not affecting the reaction of said load cell to said vertical force vector and not substantially affecting said freely pivotal supporting contact, characterized in that said rotation limit means comprises an engaging component 19 (236) extending from said rocker pin load cell (224) generally normally to said longitudinal axis;and said restrainer means comprises first and second bumper components (238, 240) mutually spaced apart a distance representing a predetermined limit and located for freely abutting contact with said engaging component (236) upon rotation of said load cell (224).
  6. 10
    Weighing apparatus comprising a base (22), a load receiving surface (12), at least one self-erecting rocker pin load cell (150) having a vertically aligned longitudinal axis and upper (86) and lower (106) contact surfaces positioned between said base (22) and said load receiving surface for freely pivotal supporting contact with said load receiving surface, said load cell being subject to both vertical and temporary transverse force vectors creating transient rotational force vectors urging said rocker pin (40) to rotate about said longitudinal axis, said load cell further comprising restrainer means for providing a rotationally stable reference isolated from said rocker pin, and rotation limit means in contact with said load cell (150) and coupled with said restrainer means so as to restrict said rotation of said load cell (150) within predetermined limits by counteracting only said rotational force vectors while not affecting the reaction of said load cell to said vertical force vector and not substantially affecting said freely pivotal supporting contact, characterized in that said rotation limit means comprises first and second oppositely disposed resiliently deformable springs (188, 190) fixed to and extending outwardly from said load cell (150) generally normally to said longitudinal axis to respective first and second bumper surfaces (156, 158) of said restrainer means, said first and second bumper surfaces (156, 158) being mutually spaced apart and positioned for freely abutting engagement with one of said first and second resiliently deformable springs (188, 190) upon rotational movement of said load cell (150) toward a predetermined limit. 21