Abstract: The subject recoil pad for rifles and shotguns is a one-piece plastic spring comprising a base which attaches to the end of the butt of the rifle or shotgun, a working part which, in use, contacts the user's shoulder and two struts interconnecting the base and working part. In plan view the pad has an elongated egg shape, matching the shape of the end of the butt. The base, working part and struts are all essentially flat, the base and working part being parallel to each other and about 3/8 of an inch apart. The struts extend from the ends of the working part at an angle to the base so that the junctures of the struts and base are some distance from the ends of the base. The angles are in the range of 30.degree. to 50.degree. with 40.degree. preferred.

Abstract: Systems including piezoelectric sensor elements advantageously mounted between supporting hard plastic material of various types or other mechanically similar materials. The sensor can further be supported by backup plate structures. Some backup plates show full shoe coverage and others show partial sole coverage. Detachable mounting formed by mechanically interengaging parts allow transducer inserts to be made in a modular manner for use in different sensor shoes or sensor insole pads, thus allowing many more patients to be analyzed and treated through use of the invention. Also disclosed is a digital charge signal integrator circuit.

Abstract: Hoof force detection apparatus having shoe portions adapted for connecting to the hooves of hoofed animals. The apparatus also includes piezoelectric elements mounted on sensor mounting sections which are connected to the shoe portions using flexion joints. The flexion joints allow forces applied to the animal's hooves through the shoe to be accommodated without applying undesirable bending moments and shear forces which would render output signals from the piezoelectric elements unreliable. Preferred forms of shoe-transducer structures include a plurality of spokes extending from shoe portions to centrally positioned sensor mounting sections. Other forms have sensors mounted in the shoe portions. The piezoelectric sensor structures preferably include a ceramic piezoelectric element protected by a cap having a flange. The protective cap and piezoelectric element are held in place by a mounting ring in some preferred embodiments. Backup plates can be used to properly support the sensor structures.