Abstract: An improved method for precision control of a wide variety of work material liquids and an improved pinch valve incorporating that method is disclosed. The method involves constricting a discrete site on a resilient tube having liquids flowing therethrough to pinch off flow, then moving the constriction upstream to maintain flow stoppage and create a partial vacuum to cause positive suck back, the distance the constriction is moved being selectively determinable to selectively adjust suck back. An apparatus for practicing the method comprises an external roller shutoff member which is movable in a direction to intersect with and then move counter to work material flow within a resilient tube to compress the tube against a ramp and gives positive repeatable shutoff of the flow.

Abstract: A toggle switch includes a double-pivoting actuator for alternately actuating at least a pair of switches and a pivotable toggle lever having detents for maintaining the toggle lever in one or more positions. The toggle lever includes a spherically shaped pivot portion which is provided with a pair of flat surfaces for preventing rotation of the toggle lever about its longitudinal axis.

Abstract: An electrical switch apparatus includes at least a pair of electrical switches and an actuating mechanism for sequentially actuating the switches. Each of the switches includes a push button which is movable between first and second positions, and the actuating mechanism includes an actuator which is movable between a first position, at least one intermediate position, and a third position. The actuator includes a cam for each of the push buttons. One of the cams is engageable with one of the push buttons to move the push button to its second position as the actuator moves to an intermediate position, and the other cam is engageable with the other push button to move the push button to its second position as the actuator moves to its third position.

Abstract: A method of forming an electrical contact in an electrical component includes the steps of punching an opening in the electrical component, moving a strip of contact material over the electrical component, shearing a piece of contact material from the strip and inserting it into the opening, and forming the piece into a contact.