Force transducers for fitting in force plates

• US 4,974,454 A
• Filed: 04/20/1989
• Issued: 12/04/1990
• Est. Priority Date: 05/18/1988
• Status: Expired due to Fees

• Current Assignee: Kistler Instrumente AG (Kistler Holding AG)
• Original Assignee: Kistler Instrumente AG (Kistler Holding AG)
• Inventors: Wolfer, Peter, Sonderegger, Hans C.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/340,706
• Time in Patent Office: 593 Days
• Field of Search: 73/862.04, 73/862.05, 73/862.06, 73/862.38, 73/862.62, 73/862.65, 177/132, 177/133, 177/134, 177/211
• US Class Current: 73/862.541
• CPC Class Codes: A61B 5/1036 Measuring load distribution, e.g. podologic studies
• CPC Class Codes: B23Q 17/0966 by measuring a force on parts of the machine other than a motor
• CPC Class Codes: G01G 19/44 for weighing persons
• 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: G01L 5/167 using piezoelectric means

Abstract

A force transducer with an electromechanical transducer element for fitting in force plates (i.e. measuring platforms) includes adjacent a first axial end a radial mounting flange with a greater outside diameter than that adjacent the second axial end. This make it possible, after connecting the signal lines, to insert the transducer in a mounting hole of the base plate of the force plate and then fix it by welding, brazing, soldering or cementing. The transducer with its signal lines thus becomes an integral part of the base plate and is sealed completely against outside influences. The recesses of the base plate may be filled with a curable resin, providing further portection against mechanical shocks and corrosion influences while at the same time enhancing the rigidity of the force plate.

Claims

1. Force transducer with an electromehanical transducer element fore fitting in a base plate of force plates having at least a first mounting hole, comprising:

a first radial mounting flange, adjacent at least a first axial end of said transducer with greater outside diameter than the outside diameter adjacent a second axial end of the transducer, for engaging said first mounting hole and fixing the transducer tightly sealed in said first mounting hole;

said first mounting hole having a diameter at least equal to the outside diameter of said first radial mounting flange for a substantial portion of the length of said transducer; and

an axial mounting extension extending from said second axial end of said transducer and including a central through hole for receiving a preloading screw.

2. Force transducer according to claim 1, including a second radial mounting flange adjacent said second axial end with smaller outside diameter than the outside diameter of the first mounting flange, for fitting in a second mounting hole in the base plate oriented essentially coaxial to the first mounting hole.

3. Force transducer according to claim 1, including signal lines exiting said transducer radially at a point located between its axial ends.

4. Force transducer with an electromehanical transducer element for fitting in a base plate of force plates having at least a first mounting hole, comprising:

a first radial mounting flange, adjacent at least a first axial end of said transducer with greater outside diameter than the outside diameter adjacent a second axial end of the transducer, for engaging said first mounting hole and fixing the transducer tightly sealed in said first mounting hole;

said first mounting hole having a diameter at least equal to the outside diameter of said first radial mounting flange for a substantial portion of the length of said transducer; and

an axial mounting extension extending from said second axial end of said transducer and including an external thread, to be received by a clamping nut acting on the base plate of the force plate to preload the measuring assembly of the transducer element.

5. Force transducer with an electromehanical transducer element for fitting in a base plate of force plates having at least a first mounting hole, comprising:

a first radial mounting flange, adjacent at least a first axial end of said transducer with greater outside diameter than the outside diameter adjacent a second axial end of the transducer, for engaging said first mounting hole and fixing the transducers rightly sealed in said first mounting hole;

said first mounting hole having a diameter at least equal to the outside diameter of said first radial mounting flange for a substantial portion of the length of said transducer; and

a threaded hole at the first axial end of the transducer facing the mounting flange.

6. Force plate comprising:

a base plate with at least a first mounting hole;

a force transducer having an electromehanical transducer element, including a first radial mounting flange adjacent at least a first axial end of said transducer with greater outside diameter than the outside diameter adjacent a second axial end of the transducer, for engaging said first mounting hole and fixing the transducer tightly sealed in said first mounting hole in said a base plate of the force plate; and

said first mounting hole having a diameter at lest equal to the outside diameter of said first radial mounting flange for a substantial portion of the length of said transducer.

7. Force plate according to claim 6 wherein said transducer includes a second radial mounting flange adjacent said second axial end with smaller outside diameter than the outside diameter of the first mounting flange, for fitting in a second mounting hole in the base plate oriented essentially coaxial to the first mounting hole.

8. Force plate according to claim 6 wherein said base plate includes a recess and said transducer includes signal lines running through the recess in the base plate.

9. Force plate according to claim 8 wherein the recess in the base plate accommodating the signal lines is filled with an insulating setting gel or curable resin.

10. Force plate according to claim 8 wherein one or more booster amplifiers are electrically connected to said transducer element and are located in the recess of the base plate.

11. Force plate according to claim 6, wherein the mounting flange of the force transducer is joined to the base plate by one of the following:

welding, brazing, soldering or cementing.

12. Force plate according to claim 6, wherein the base plate is in the form of a box section.

13. Force plate according to claim 6, wherein the base plate is solid and includes a recess receiving signal lines of said transducer.

14. Force plate according to claim 6, wherein said transducer includes an axial mounting extension extending from said second axial end of said transducer, the mounting extension including a central through hole for receiving first fixing screw which extends from the central thorough hole for securing the baseplate to a subfloor.

15. Force plate according to claim 14, wherein the base plate has a two-stage hole in which is positioned the mounting extension;

and

the first fixing screw rests on the shoulder of the two-stage hole.

16. Force plate according to claim 15 including a cover plate adjacent said first axial end of said transducer and having a hole through which a second fixing screw secures the cover plate to a threaded hole in said first axial end of said transducer.

17. Force plate according to claim 14 including a cover plate adjacent said first axial end of said transducer and having a hole through which a portion of said first fixing screen passes to secure said cover plate to said base plate.

18. Force plate according to claim 17, wherein the first fixing screw preloads said transducer.

19. Force plate according to claim 6 including a cover plate adjacent said first axial end of said transducer and having a hole through which a fixing screw secures the cover plate to a threaded hole in said first axial end of said transducer.