Abstract: A first steerable prime mover wheeled tower and a plurality of laterally spaced intermediate and end towers collectively carry a horizontal irrigation conduit which receives water through a hose dragged behind the prime mover wheeled tower. The irrigation conduit is supported by a truss structure extending between the tops of the several towers. Electric drive motors on the individual towers are powered in proper sequence to cause the intermediate and end wheeled towers to follow the linear path of the prime mover wheeled tower without appreciable lag. A system of control switches responds to tension in a control cable connected with a spring-loaded crank element on the prime mover wheeled tower to produce automatic activation of the control switches.

Abstract: A pressure switch and method of manufacture wherein a resiliently yieldable intermediate open layer is sandwiched between flexible conductive layers, all of which is enclosed between flexible outer layers, so that in the unstressed or relatively unstressed condition the contact layers are spaced apart by the intermediate layer, while flexure or other sufficient stressing of the assembly effects contact of the contact layers through the open intermediate layer.

Abstract: A pressure sensitive door edge construction including a channel facing outwardly from a door and having inturned lips defining therebetween a slot, a resiliently depressible bead extending exteriorly along the channel bridging the slot, a reduced neck on the inner side of the bead extending through the slot, and inner enlargement on the neck interiorly of the channel, and pressure responsive means operatively connected to the bead for stopping door movement upon bead depression.