Abstract: A system for monitoring the condition of elongate structural elements, for example, railway rails, and a method of designing and manufacturing the system is disclosed. The method includes identifying and selecting suitable modes of propagation and signal frequencies that can be expected to travel large distances through an elongate structural element; designing a transducer that will excite the selected mode at the selected frequency; numerically modelling the transducer as attached to the elongate structural element; validating the transducer design by analysing a harmonic response of the selected mode of propagation to excitation by the transducer, and manufacturing one or more transducers for use in the system.

Abstract: A system for monitoring the condition of elongate structural elements, for example, railway rails, and a method of designing and manufacturing the system is disclosed. The method includes identifying and selecting suitable modes of propagation and signal frequencies that can be expected to travel large distances through an elongate structural element; designing a transducer that will excite the selected mode at the selected frequency; numerically modelling the transducer as attached to the elongate structural element; validating the transducer design by analyzing a harmonic response of the selected mode of propagation to excitation by the transducer, and manufacturing one or more transducers for use in the system.

Abstract: THIS invention relates to a piezoelectric actuation device and more particularly but not exclusively, to a piezoelectric actuation device with three piezoelectric actuator sets. The device includes a first clamp arrangement being displaceable between an engaged position and a disengaged position and a second clamp arrangement being displaceable between an engaged position and a disengaged position. The device also includes an actuation arrangement being displaceable between a first condition and an inverse second condition; and force transmission means for transmitting a force to a load applied thereto, with the force transmission means being coupled to the actuation arrangement. The device is characterized in that the actuation arrangement displaces the force transmission means when it is displaced from the first condition to the second condition, and also displaces the same force transmission means when it is displaced from the second condition to the first condition within a single actuating cycle.

Abstract: The invention relates to a system for monitoring the condition of elongate structural elements and more particularly but not exclusively, to a system for monitoring and detecting cracks and breaks in railway rails. The invention furthermore extends to the methodology of designing and developing such a system. The method includes the steps of identifying modes of propagation and signal frequencies that can be expected to travel large distances through an elongate structural element; selecting a suitable mode of propagation and frequency of operation; designing a transducer that is adapted to excite the selected mode at the selected frequency; numerically modelling the transducer as attached to the elongate structural element; and analyzing a harmonic response of the selected mode of propagation to excitation by the transducer in order to validate the transducer design.

Abstract: The invention relates to a method of actuating by means of a wax actuator and to a wax actuator. The wax actuator (10, 100, 200) includes a wax expansion generator comprising a housing (12) defining a chamber (18) which is partially filled with wax (20.1) and partially filled with hydraulic fluid, the wax (20.1) and the hydraulic fluid being separated by at least one sealing interface (20.2, 202), and heating means (22) for heating the wax (20.1) to cause it to melt and expand. The wax actuator (10, 100, 200) further includes a hydraulic transmission device comprising a hydraulic line (38) in communication with the hydraulic fluid within the chamber (18) and a connector (40) at a downstream end of the hydraulic line (38) for use in connecting the hydraulic line (38) to a working object.

Abstract: A strain/electrical potential transducer (10) includes a rigid base (12), a rigid beam (18) hinged to the base (12) at (20), an elongate stack (14) of dielectric substance, e.g. piezoelectric material, generally parallel with the beam (18) and hinged to the base at (16), and a rigid link (22) interconnecting ends of the beam and stack remote from the base (12). The transducer can be operated as a displacement generator by applying potential difference to the stack (14) via contacts (15) to strain the stack (14) and to cause amplified, transverse displacement as shown at (32). Conversely, the transducer can be operated as a sensor. Displacement at (32) causes strain in the stack (14) which generates a potential difference at the contacts (15). Composite transducers are disclosed. A manipulating device in the form of an arrangement of displacement generators and use thereof for microscanning are disclosed.

Abstract: A strain/electrical potential transducer (10) includes a rigid base (12), a rigid beam (18) hinged to the base (12) at (20), an elongate stack (14) of dielectric substance, e.g. piezoelectric material, generally parallel with the beam (18) and hinged to the base at (16), and a rigid link (22) interconnecting ends of the beam and stack remote from the base (12). The transducer can be operated as a displacement generator by applying potential difference to the stack (14) via contacts (15) to strain the stack (14) and to cause amplified, transverse displacement as shown at (32). Conversely, the transducer can be operated as a sensor. Displacement at (32) causes strain in the stack (14) which generates a potential difference at the contacts (15). Composite transducers are disclosed. A manipulating device in the form of an arrangement of displacement generators and use thereof for microscanning are disclosed.