1534276-A is referenced by 14 patents.
1534276 Force transducers EMI Ltd 2 Feb 1976 [1 Feb 1975 (2)] 4465/75 Heading G1N A force transducer includes a planar element in the form of a beam 6 with strain-sensing resistors 1-4 on its upper surface on reduced thickness portions 7, and having parallel limbs AD, BC and a re-entrant portion between them for application of a force at P, which portion projects into a central aperture. In use the beam is clamped along the edge AB and flexes substantially only in the portions 7 of reduced thickness (as shown in Fig. 2) where resistors 1, 2 are strained in the opposite sense to resistors 3, 4, these resistors being connected in a Wheatstone bridge circuit. In an alternative embodiment Piezo resistors 3-10 are provided on a semi-conductor beam 1 by differential doping.; The beam is rigidly mounted along its edge AB and a force applied vertically downwards at P produces flexing at the reduced thickness areas 2 whereby resistors 5,6,7,8 are strained in the opposite sense to 3,4,9,10. In a further embodiment the parallel limbs and re-entrant portion each have four sections of reduced thickness and associated strain gauges, four gauges on each parallel limb and eight on the re-entrant portion, which is double the width of each parallel limb.