Abstract: An inertial force transducer having an operative frequency range comprises a resonant element having a frequency distribution of modes in the operative frequency range of the transducer and a coupler for mounting the resonant element to a site to which force is to be applied. The resonant element is a piezoelectric device comprising a layer of piezoelectric material and a substrate layer on the layer of piezoelectric material. The substrate layer has a region extending beyond the piezoelectric layer, with the coupler mounted to the extended region whereby the low frequency performance of the transducer is extended.

Abstract: An electromechanical force transducer comprising a plurality of resonant elements, a low stiffness member coupled between the adjacent faces of at least two adjacent resonant elements, and a stub member on which the resonant elements are supported and for coupling the transducer to a site to which force is to be applied. An electromechanical force transducer comprising a plate-like resonant element having a frequency distribution of modes in the operative frequency range of the transducer, and a stub member for coupling the transducer to a site to which force is to be applied and on which the resonant element is supported and arranged such that whole body non-bending modes are introduced into the resonant element.

Abstract: A mould is provided for the making and holding of working models for the manufacture of false teeth. The mould has upwardly extending side walls 11, 12, 13 and 14 and means to retain moulded material within the mould. The retaining means comprises at least one retaining member such as a locking strap 16 which, in use, is passed through at least one side wall of the mould to project into the moulded material.