FI92140C - Three-way power measuring device - Google Patents

Description

92140

THREE - WAY FORCE MEASURING DEVICE

The invention relates to a three-way force measuring device comprising a force receiving body, e.g. from the free ends where the strain-10 strip sensors are placed to measure the forces in proportion to the deflections of the arms.

Various force measuring devices are used in sports science research. Especially in sports that require walking, running and effort, the force applied by the athlete to the ground and its use over a period of time is desired to be known accurately. It is thus mainly a force plate measuring forces in three directions as a person moves to measure the effort forces of the birth canal.

20 Power plates of this type are constructed of three unidirectional force sensors by mounting them perpendicular to each other. A complex bearing and suspension system is required to prevent cross-forces from crosstalking, as a result of which the resonant frequency of the system remains too low to measure the impact forces.

There are also one-piece, three-way force sensors. Their weakness is, in addition to the complex and expensive structure, the crosstalk of cross-forces, which makes them impossible to use in accurate measurements.

The object of the present invention is to provide a new type of sensor structure which does not have the above-mentioned drawbacks. The characteristic features of the invention are set forth in the appended claims. Because the pivot bearing does not transfer torque, the crosswise free ends of the arms can bend freely according to the force to be measured. In this case, the neutral axes are also maintained at the level of symmetry of the arms.

40 2 92140

The invention will now be described with reference to the accompanying drawings, which show a force measuring device according to the invention.

5 Figure 1 shows the force measuring device seen from above

Figure 2 shows the device of Figure 1 seen from the side and partly in section

Figure 3 shows a section from point III-III in Figure 1 Figure 4 shows the force measuring arms with their connections 10

Figures 1-4 show a device for measuring intense effort. In it, the effort level 1 is connected to the base 1 by means of support members located at both ends, which include arms (4 and 6) and a joint (5) between them. 15 The joint (5) is placed on the free ends of the arms so that no torque is transferred between the arms. In connection with each joint (5), strain gage sensors are mounted on the arms (4,6) to measure forces in different directions from different angles of the tension plane (1). Adding these together gives the components of the tensile force. The measurement can be performed continuously and the cut-off frequency of 200 Hz required to measure man-made forces is easily achievable.

Figure 3 shows a detailed attachment of the arms. Attached to the base-25 part (2) is a transverse arm (6), each end of which forms the aforementioned free end (3). A first arm (4) is fastened to it in the transverse direction in the longitudinal direction of the tension plane (1) by means of a joint (5). The effort level (1) is attached to this arm (4) at the opposite end of the hinge-30 attachment.

Figure 4 shows the arms (4 and 6) removed from the device. The first arm (4) includes strain gauge sensors (9) measured in the transverse direction of the effort level and the second arm (6) 35 includes strain gauge sensors (10 and 11) measuring both length and height. All strain gage sensors (9, 10 and 11) are placed symmetrically in the neutral plane of the arms (4 and 6). . regarding. Optionally, the strain gauge sensors include temperature compensation strips in a known manner.

Claims (4)

A three-way force metering device, which comprises a receiving piece for the force, for example, a tapping level (2), lower part (1) and two bars (4, 6), it understandably obtained at the receiving piece for the force and with a free spirit and the other placed substantially in a perpendicular direction to the grasp and grasp of the base and also this with a free spirit and which bars are connected to each other by their free spirits, on which the transducers (9 - 11) are placed to measure the forces relative to the bending of the bars. , characterized by. that the bonding of the rods (4, 6) is challenged by means of a joint bearing (5) which is placed at the intersection of the neutral axes of the rods. 25 2. The power metering device according to claim 1, characterized by. that, to the lower part (1) in the middle, there is obtained a substantially as wide bar as the device is wide, the spirits of the spring rod thus constitute two free spirits, both of which have been obtained with the said understanding rod (4). 3. Power metering device according to claim 1 or 2, characterized by. that the towing sensors are placed on the bars in pairs symmetrically in relation to the neutral axes. 4. Power metering device according to claim 3, characterized by. that on the understanding rod (4) is placed a pair of strain gauges aimed to measure the force in the direction of the second rod (6) and on the second rod (6) a pair of strain gauges (10, 11) to measure it and inboard cross forces . II