Force measuring device

• US 4,744,254 A
• Filed: 12/12/1986
• Issued: 05/17/1988
• Est. Priority Date: 12/18/1985
• Status: Expired due to Fees

• Current Assignee: Pfister GmbH
• Original Assignee: Pfister GmbH
• Inventors: Barten, Hans
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/941,213
• Time in Patent Office: 522 Days
• Field of Search: 73/862.65, 73/862.66, 177/211, 177/DIG. 9, 177/134
• US Class Current: 73/862.622
• CPC Class Codes: G01G 21/23 Support or suspension of weighing platforms G01G21/24 takes precedence
• CPC Class Codes: G01G 3/1402 Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
• CPC Class Codes: G01L 1/2206 Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
• CPC Class Codes: G01L 1/26 Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload
• CPC Class Codes: Y10S 177/09 Scale bearings

Abstract

A force measuring device of unitary design comprising a beam provided with force sensitive elements supported on a base plate by support elements at a closed distance, the support elements being housed in recesses provided at bottom surface of said beam and a top surface of said base plate. Since the support elements are integrated in said beam no separate support elements are necessary for supporting said force measuring device such that lateral forces are compensated.

Claims

1. A force measuring device comprising:

a beam including a body provided with force sensitive means responsive to strain or shearing forces exerted onto said beam, an upper surface of said beam being formed for force introduction to said beam and a bottom surface of said beam having formed therein recesses at outward regions of said beam;

a base plate having a top surface in parallel to said bottom surface of said beam and being provided with recesses aligned to corresponding of said recesses provided at said bottom surface of said beam; and

support elements loosely fitting into said recesses in said bottom surface of said beam and said top surface of said base plate, having opposite curved surfaces for engaging bottom surfaces of said recesses and having a size adapted to maintain a relatively small gap between said bottom surface of said beam and said top surface of said base plate,

the arrangement being such that a unitary force measuring device is formed with lateral force components being compensated by restoring forces caused by said support elements being rocked to slanted position by said lateral force components and an excess lateral movement of said beam relative to said base plate being limited by a restricted skewing of said support elements in said recesses.

2. The force measuring device of claim 1 wherein said recesses are of generally cylindrical shape.

3. The force measuring device of claim 2 wherein a diameter of said cylindrical recesses is in the range of 70 to 90% of a diameter of said support elements, a height of said support elements being in the range of two to three times of their diameters.

4. The force measuring device of claim 1 wherein said recesses in said bottom surface of said beam have a remarkably larger height than said recesses in said top surface of said base plate.

5. The force measuring device of claim 1 wherein said force-sensitive means and said support elements are arranged symmetrically to a vertical plane through said beam, said force-sensitive elements being arranged closer to said plane than said support elements.

6. The force measuring device of claim 1 wherein adjacent to each said curved opposed surface of said support elements an elastic ring is provided, said elastic ring sealing and centering said support element.

7. The force measuring device of claim 1 wherein said force-sensitive means and said support elements are symmetrically arranged about a central vertical axis extending in a direction of force application onto said beam, said force sensitive means being arranged closer to said axis than said support elements.

8. The force measuring device of claim 1 wherein said gap between said bottom surface of said beam and said top surface of said base plate is in the range of one millimeter to one centimeter.

9. The force measuring device of claim 1 wherein surfaces in said recesses engaging said opposed curved surfaces of said support elements are curved in the same sense as but less than said opposed curved surfaces of said support elements.

10. The force measuring device of claim 1 wherein said beam, said base plate and said support elements are made of stainless steel.

11. The force measuring device of claim 1 wherein said upper surface of said beam has mounted thereon a force introduction member by means of a bearing permitting tilting of said force introduction member in respect of a horizontal plane.

12. A force measuring device comprising:

a beam including a body provided with force sensitive means responsive to strain or shearing forces exerted onto said beam, an upper surface of said beam being formed for force introduction to said beam and a bottom surface of said beam having formed therein cylindrical recesses at outward regions of said beam;

a base plate having a top surface in parallel to said bottom surface of said beam and being provided with cylindrical recesses aligned to corresponding of said cylindrical recesses provided at said bottom surface of said beam; and

cylindrical support elements loosely fitting into said cylindrical recesses in said bottom surface of said beam and said top surface of said base plate, having opposite curved surfaces for engaging bottom surfaces of said cylindrical recesses and having a size adapted to maintain a relatively small gap between said bottom surface of said beam and said top surface of said base plate,

the arrangement being such that a unitary force measuring device is formed with lateral force components being compensated by restoring forces caused by said cylindrical support elements being rocked to slanted position by said lateral force components and an excess lateral movement of said beam relative to said base plate being limited by restricted skewing of said cylindrical support elements in said cylindrical recesses, wherein said cylindrical recesses in said bottom surface of said beam having a remarkably larger height than said cylindrical recesses in said top surface of said base plate.