Abstract: A method and device for filling a container with liquid up to a predetermined level. The device includes a cylinder and a piston movable within the cylinder between a rest position and a fill position. A supply of liquid for filling the container is provided to a first end of the piston at alternating pressures to cycle the piston back and forth between the rest and fill positions. Each time the piston reaches its fill position, supply liquid is added to the container. With each cycle the device draws fluid from the container and then attempts to compress the drawn fluid with a second end of the piston. When the fluid drawn is gas, the piston can compress the gas to continue moving to the fill position. When the drawn fluid is liquid, the piston can not compress the liquid and thus is stopped to prevent further filling.

Abstract: A low-cost, easy to manufacture and maintain pressure responsive switch. The switch includes a pressure responsive diaphragm made from latex rubber that is mounted in a housing base. An annular groove in the housing base communicates with an annular shoulder in a housing cover to compress an O-ring for forming upper and lower chambers, sealing the housing and securing the diaphragm.

Abstract: A sensing edge for controlling movement of a door by actuation of a device upon an external force being applied to the sensing edge. The sensing edge includes an elongated, generally flexible tubular sheath which is secured to the door. The sheath includes an elongated, entirely hollow cavity with an optically reflective interior surface. A light transmitter is positioned proximate a first end of the sheath for transmitting a light beam toward a second end of the sheath. A light detector is positioned proximate the second end of the sheath for detecting the presence or absence of the light beam at the second sheath end. The light detector generates a signal for actuating the device upon detecting the absence of the light beam at the second end of the sheath.

Abstract: A sensing device for use with a door movable in a first direction by an actuator is employed to stop or reverse the direction of movement of the door upon a force being applied to the sensing device by an object in the path of movement of the door. The sensing device comprises a sensing edge for being secured to the door. The sensing edge includes a generally flexible elongated sheath and a pair of generally parallel spaced contact members disposed within the sheath. The contact members are electrically connected to the actuator. A termination circuit is electrically connected to the contact members for generally continuously generating an installer selected predetermined output which is applied through the contact members to the actuator to enable operation of the actuator for movement of the door in the first direction.

Abstract: A sensing edge for a gate to protect persons, equipment and the gate from impact damage. The sensing edge includes a mounting member which is snap-fit to the leading member of the gate and extends around a portion of the external surface of the leading member of the gate. An elongate outer sheath surrounds the mounting member and a switch is positioned between the sheath and mounting member for actuation of the device upon application of pressure to the exterior surface of the sheath. The sensing edge extends sufficiently around the leading and side edges of the leading member to permit the device to be actuated in response to forces which approach the leading member at an angle.

Abstract: A sensing edge for causing an object moving in a first direction to move in a second direction by actuation of a device upon force being applied to the sensing edge. The sensing edge includes a base member for being secured to the object. A first elongate wall extends from the base member to form a generally enclosed cavity. A second elongate wall extends from the base member such that the second wall is positioned within the cavity between the first wall and the base member. A switch is positioned within the cavity between the first and second walls for actuation of the device upon application of external pressure to the first wall.

Abstract: A redundant sensing edge for a door to protect persons, equipment and the door from impact damage by actuating a device upon detecting an object in proximity to the door edge. The sensing edge includes an elongate outer sheath compressible upon application of external pressure. A force sensing switch is positioned within the elongate outer sheath for sensing the application of force to the sheath. Upon force being applied to the sheath, the force sensing switch actuates the device for controlling the door. The sensing edge also includes a proximity sensing switch for detecting the presence of an animate object in proximity to the door edge. The proximity sensing switch includes an electrical circuit positioned near the elongate sheath and a control circuit for detecting changes in the capacitance of the electrical circuit. An animate object in proximity to the elongate sheath changes the capacitance of the electrical circuit.