Abstract: An extendible ramp for entrance to or egress from vehicles, such as buses, includes sensors arranged to detect whether the ramp abuts an obstruction. The ramp assembly comprises a chassis, a ramp extendible from the chassis, a frame which carries the chassis and a sensor arranged to sense movement of the chassis relative to the frame. The chassis is mounted in the frame such that it moves relative to the frame in response to both abutment of the leading edge of the ramp against an obstacle and in response to vertical force applied to the top of the extended, or partially extended ramp. The chassis also moves relative to the frame in response to a force applied to the side of the extended or partially extended ramp.

Abstract: A method for hierarchical very large scale integration design comprises representing a structure of the hierarchical very large scale integrated design as a graph comprising design objects. The method further comprises specifying a transformation behavior applied to the design objects, and processing, top-down, the graph to perform the transformation on the hierarchical very large scale integrated design.

Abstract: There is provided screen apparatus comprising side walls having a lower edge portion configured to accept tubular screen support members. An upper edge extends from the inlet end of the side walls to an apex from which a declining edge extends to the foot of the side walls. The lower edge, upper edge and declining edge are each provided with edge stiffening. A torque tube is secured between the respective exciter mount castings, the torque tube and stiffened side wall being selected to provide that the first fundamental frequency mode greater than the exciter frequency is at least 2 Hz greater than the exciter frequency and the first fundamental frequency below the exciter frequency is at least 2 Hz lower than the exciter frequency.

Abstract: An extendable ramp assembly includes a chassis, a first ramp slidably movable relative to the chassis and hingably connected to the chassis, and a second ramp carried by the first ramp and movable relative to the chassis and the first ramp. Separate structure is provided for extending and retracting both the first and second ramps. A first mechanism is provided for detecting whether either or both of the first and second ramps abuts an obstruction when at least one of the ramps is being extended. A second mechanism is provided for stopping the extension of at least one of the ramps or for retracting at least one of the ramps in the event of the detecting mechanism detecting the obstruction.

Abstract: There is provided screen apparatus comprising side walls having a lower edge portion configured to accept tubular screen support members. An upper edge extends from the inlet end of the side walls to an apex from which a declining edge extends to the foot of the side walls. The lower edge, upper edge and declining edge are each provided with edge stiffening. A torque tube is secured between the respective exciter mount castings, the torque tube and stiffened side wall being selected to provide that the first fundamental frequency mode greater than the exciter frequency is at least 2 Hz greater than the exciter frequency and the first fundamental frequency below the exciter frequency is at least 2 Hz lower than the exciter frequency.