Measuring and testing – Dynamometers – Responsive to force
Patent
1986-08-07
1988-07-05
Woodiel, Donald O.
Measuring and testing
Dynamometers
Responsive to force
7386258, 7386264, 338 2, G01L 500
Patent
active
047546530
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a force measuring device for measuring a force exerted onto a force introduction member inserted into a potlike base member. In the bottom region of the interior of the base member elastomeric material is provided having embedded a pressure transducer or sensor.
BACKGROUND ART
The U.S. Pat. No. 3,410,135 discloses a force measuring device where at the bottom of a potlike base member an elastomeric block is arranged having a slightly raised peripheral lip. Patent force introduction piston having a substantially smaller diameter than the cylindrical interior of the base member fits with its lower face edge into the recess formed by the raised lip. The gap between the peripheral surface of the piston and the cylindrical inner surface of the base member is relatively large and of such a width that upon application of a force no elastomeric material is squeezed out of the base member by the piston. In view of the relatively large gap the piston may assume a certain oblique position with respect to the cylindrical interior on the base member without engaging the surface of the latter. In order to limit such an oblique position of the piston a resilient washer may be provided in the upper region of the annular gap between the piston and the interior surface of the base member. There is no connection between the elastomeric material and the metallic surfaces of the base member and the piston in contact with the elastic material. Without the washer considerable lateral forces will be transmitted to the elastomeric material and cause misreadings of the force measured. With the washer provided a new element of friction is introduced which in turn deteriorates the measuring results. Since the annular gap is relatively wide elastomeric material will be pressed into it at least upon application of large forces which gives rise to further inaccuracies of the measurement.
The U.S. Pat. No. 4,175,429 discloses a force measuring device comprising a pressure sensitive metal wire embedded in a block of vulcanized silicon rubber provided at the bottom of a cylindrical recess in a base member and compressible by means of a movable piston acting as a force introduction member onto the silicon rubber. A considerable space is allowed between the interior cylindrical wall of the base member and the peripheral surface of the piston. In order that a clearance may be maintained as large as possible a sealing ring is provided at the edge of the lower face surface of the piston in contact with the silicon rubber. The sealing ring is in contact with the cylindrical surface of the interior of the base member which results in a considerable friction affecting the accuracy of the force measuring device. Furthermore, any lateral force component of a force applied at an oblique angle onto the force introduction member acts at least partially onto the elastomeric material which again deteriorates the accuracy of measurement.
DISCLOSURE OF THE INVENTION
It is an object of the invention to provide a force measuring device having a simple design and excellent operating parameters.
Another object of the present invention is to provide a force measuring device which is insensitive to lateral force components whilst exactly measuring the vertical force component of a force applied to the force introduction member at an oblique angle.
Still another object of the present invention is a method for producing force measuring devices with increased accuracy.
These and other objects of the invention are achieved by the device and the method as defined in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the principle design of a force measuring device according to the invention in a vertical sectional view,
FIG. 2 is a side view partially in section illustrating a force measuring device produced with an apparatus according to FIG. 5,
FIG. 3 is a top view of the force measuring device of FIG. 2,
FIG. 4 is a side view partially in section of a second embodiment of a force measuring
REFERENCES:
patent: 1994388 (1935-03-01), Erichsen
patent: 2847707 (1958-08-01), Sullivan
patent: 3410135 (1968-11-01), Reynand
patent: 3582691 (1971-06-01), Sonderegger et al.
patent: 4127788 (1978-11-01), Daugherty
patent: 4167381 (1979-09-01), Hilmoe
patent: 4175429 (1979-11-01), Keck
patent: 4383584 (1983-05-01), Dyck
patent: 4644805 (1987-02-01), Hafner
Bock Gunter
Hafner Hans W.
Pfister GmbH
Woodiel Donald O.
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