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: From one aspect, the invention is a method of making a bending wave panel loudspeaker, comprising rigidly coupling a lever to a panel edge or marginal portion such that the lever extends at an angle to the plane of the panel, coupling a bending wave exciter to the lever whereby bending wave energy is coupled to the panel to produce an acoustic output when the exciter is fed with a signal and supporting the panel on a suspension positioned outboard of the lever. From another aspect the invention is a bending wave panel-form loudspeaker having a lever rigidly coupled to a marginal portion or edge of the panel, a vibration exciter coupled to the lever to apply bending wave energy to the panel to produce an acoustic output and a panel suspension positioned outboard of the lever. From a further aspect, the invention is a small electronic device, e.g.

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 caster is provided with two braking mechanisms and/or a locking mechanism. One embodiment of the present invention provides a castor including a wheel having an axis of rotation and a mounting bracket for a load. A brake lever is attached to the wheel adjacent the axis of rotation and pivotally attached to the mounting bracket. The brake lever is movable to selectively place the wheel and mounting bracket in a locked position or a rotation position. A first brake surface is associated with the mounting bracket and contacts the wheel when the wheel is in the locked position to substantially restrict wheel rotation. A second brake member, having a second brake surface, is linked to the mounting bracket and the brake lever so that the second brake surface contacts the wheel when the wheel is in the locked position. In an alternate embodiment, a lock mechanism is associated with the castor and is selectively engagable to restrict the wheel from moving from the locked position to the rotation position.