Flexure base scale

Claim 2

In a weighing scale, a rigid framework, a load supporting member for receiving a load to be weighed in such manner that the load exerts a force on said member, lever means for translating the forces exerted by a load on said load supporting member to output transducer means for indicating the weight of the load, said lever means including a pair of levers each having a fulcrum portion and an arm portion, said lever means also including a transfer member connected to the arm portions of said pair of levers for transferring forces from said arm portions to the output transducer means, and flexure means connecting each of said levers to said load supporting member and said framework in such manner that a force exerted on said supporting member by a load produces a torque in the fulcrum portion and a force in the arm portion of the lever arm, said flexure means including first and second generally rectangular flexure plates disposed in substantially parallel vertical planes on opposite sides of the fulcrum portion of said lever, means rigidly affixing the upper and lower portions of the first flexure plate to said framework and said fulcrum portion in such manner that the central portion of said flexure plate is free to flex without contacting either said framework or said lever, and means rigidly affixing the upper and lower portions of the second flexure plate to said fulcrum portion and said load supporting member in such manner that the central portion of said second flexure plate is free to flex without contacting either said lever or said supporting member.

Claim 3

In a weighing device, a generally rectangular framework including two oppositely disposed side members, a pair of fulcrum members within the area defined by said framework, each of said fulcrum members being parallel to the proximate one of the oppositely disposed side members, flexure means including generally rectangular flexure plates intermediate said fulcrum members and said side members for pivotally mounting said fulcrum members to said side members, main lever arms rigidly secured at one end to said fulcrum members and extending normaLly from said fulcrum members, the free ends of said lever arms being in proximity to each other, platform means connected to said fulcrum members through additional flexure means including generally rectangular flexure plates disposed opposite the first named flexure plates, whereby a downward force on said platform means causes a pivotal torque on at least one of said fulcrum members and a downward force on the free end of the main lever arm secured thereto, a transfer lever arm pivotally mounted at one end of said framework intermediate and parallel to said oppositely disposed side members, flexible cable means connecting said transfer lever arm to the free end of each of said main lever arms, whereby a downward force on either main lever arm causes a downward force on the free end of said transfer lever arm sensor means carried by said framework responsive to the force at the free end of said transfer lever arm, and display means controlled by said sensor means for indicating the weight of an object exerting a force of said platform means.

Claim 4

In a weighing device, a generally rectangular framework including two oppositely disposed side members, a pair of fulcrum members within the area defined by said framework, each of said fulcrum members being parallel to the proximate one of the oppositely disposed side members, flexure means including generally rectangular flexure plates intermediate said fulcrum members and said side members for pivotally mounting said fulcrum members to said side members, main lever arms rigidly secured at one end to said fulcrum members and extending normaLly from said fulcrum members, the free ends of said lever arms being in proximity to each other, platform means connected to said fulcrum members through additional flexure means including generally rectangular flexure plates disposed opposite the first named flexure plates, whereby a downward force on said platform means causes a pivotal torque on at least one of said fulcrum members and a downward force on the free end of the main lever arm secured thereto, a transfer lever arm pivotally mounted at one end of said framework intermediate and parallel to said oppositely disposed side members, flexible cable means connecting said transfer lever arm to the free end of each of said main lever arms, whereby a downward force on either main lever arm causes a downward force on the free end of said transfer lever arm sensor means carried by said framework responsive to the force at the free end of said transfer lever arm, and display means controlled by said sensor means for indicating the weight of an object exerting a force of said platform means.

Claim 5

A weighing device as in claim 2 wherein the free end of said transfer arm member and the centers of said fulcrum members and said cable means all lie in substantially the same horizontal plane.

Claim 6

A weighing device as in claim 2 wherein said platform means includes a horizontal platform member and a plurality of vertical posts, said platform member resting upon the upper ends of said posts, and the lower ends of said posts being mounted upon rigid members connected to said lever members by said additional flexure means.

Claim 7

A weighing device as in claim 2 wherein said one end of said transfer lever arm is mounted to said framework by a flexure assembly including a generally rectangular flexure plate.

Claim 8

A weighing device as in claim 2 wherein said display means is mounted in a housing independent of said framework, said display means being operably connected to said sensor means.

Claim 9

A weighing device as in claim 2 wherein said sensor means includes a load cell connected to the free end of said transfer lever arm, said load cell having an electrical resistance dependent upon the force exerted thereon by said transfer lever arm.

Claim 10

A weighing device as in claim 7 wherein said display means includes electrical signal conditioning means connected to said load cell for producing a signal having a magnitude dependent on the force exerted by said transfer lever arm and digital display means responsive to said signal for displaying the weight of an object on said platform means.

Claim 11

A weighing device as in claim 2 wherein said sensor means includes a hydraulic load cell connected to the free end of said transfer lever arm, said load cell producing a hydraulic pressure dependent upon the force exerted thereon by said transfer lever arm.

Claim 12

A weighing device as in claim 9 wherein said display means includes hydraulic pressure responsive means connected to said load cell for producing a mechanical movement having a magnitude dependent upon the force exerted by said transfer lever arm.

Claim 13

A weighing device as in claim 9 wherein said display means includes pressure transducer means connected to said load cell, said transducer means producing an electrical signal having a magnitude dependent upon the force exerted by said transfer lever arm, and digital display means responsive to said signal for displaying the weight of an object on the said platform means.

Claim 14

In a device for determining the weight of an object placed on a platform, a rigid framework forming a supporting base, a pair of main levers each including a fulcrum portion and a lever arm extending normally therefrom, flexure plate means pivotally mounting said levers to said framework in such manner that the fulcrum portions are parallel to each other and the lever arms extend toward each other, additional flexure plate means connecting the platform to the fulcrum portions of said main levers in such manner that the lever arms of said main levers coNstitute second class levers adapted for deflection in the same direction as said platform, a transfer lever arm pivotally mounted at one end to said framework, flexible means connecting the lever arms of said main levers to said transfer lever arm, and sensor means carried by said framework for detecting the force on said transfer lever arm.

Claim 15

In a device for determining the weight of an object placed on a platform, a rigid framework forming a supporting base, a pair of main levers each including a fulcrum portion and a lever arm extending normally therefrom, flexure plate means pivotally mounting said levers to said framework in such manner that the fulcrum portions are parallel to each other and the lever arms extend toward each other, additional flexure plate means connecting the platform to the fulcrum portions of said main levers in such manner that the lever arms of said main levers coNstitute second class levers adapted for deflection in the same direction as said platform, a transfer lever arm pivotally mounted at one end to said framework, flexible means connecting the lever arms of said main levers to said transfer lever arm, and sensor means carried by said framework for detecting the force on said transfer lever arm.

Claim 16

A device as in claim 12 wherein said sensor means comprises a load cell connected to the end of said transfer lever arm opposite said one end, said load cell having an electrical resistance dependent upon the force exerted thereon by said transfer lever arm.

Claim 17

A device as in claim 13 together with electrically actuated digital display means connected electrically to said load cell for visually displaying by number the weight of an object placed on the platform.

Claim 18

A device as in claim 12 wherein said sensor means comprises a hydraulic load cell engaged by the end of said transfer lever arm opposite said one end, said load cell containing volume of fluid having a pressure dependent upon the pressure exerted on the load cell by said transfer lever arm.

Claim 19

A device as in claim 15 together with pressure responsive means connected to said hydraulic load cell for indicating the weight of an object placed upon the platform.

Claim 20

A device as in claim 16 wherein said pressure responsive means includes means for producing an electrical signal dependent upon the pressure of the fluid in said load cell and digital display means responsive to said electrical signal for indicating the weight of an object placed upon the platform.