Abstract: The valving element, according to the first embodiment depicted, comprises a plate-type element having an undulated or scalloped edge or periphery. The plate-type element has a plurality of flow ports formed therein each of which subtends an arc drawn from the radial center of the element. The ends of the ports, which otherwise would be subject to fatigue, failure and fracture, are spaced further from the edge than in prior art practice. Accordingly, the shock of impact of the plate-type element on opening or closing is less likely to precipitate fatigue and failure of the port ends. Additionally, at a plurality of locations about the periphery, the plate-type element has linear portions; upon the plate-type element impacting on any of these linear portions, it will make a line contact which more readily disperses the impact shock.

Abstract: An operating scheme for electronic locks wherein both the key and the lock have a first and second combination. The lock will open when the first key combination equals the first lock combination and the second key combination equals the second lock combination. The lock recombinates to the first key combination and the second key combination when the first key combination equals the second lock combination.

Abstract: According to an embodiment thereof, the stabilizer has a generally axially-extending lip projecting therefrom for engagement (of the latter) by a powered, rotary, thrusting apparatus. The method, then, comprises forceably thrusting a stabilizer into an earth structure bore and rotating the stabilizer during the thrusting thereof, particularly with the aid of apparatus of the aforesaid type.

Abstract: The unloading means comprise unloading ports, and valving therefor, for step-control unloading of a gas compressor. In a first embodiment, the unloading means are provided in side walls of a rotary, positive displacement, gas compressor, and in an alternate embodiment the unloading means are disposed within end walls (of a rotary, positive displacement, gas compressor), and comprehends means for step-control of a plural-stage machine.

Abstract: The unloading means comprise unloading ports, and valving therefor, for step-control unloading of a gas compressor. In a first embodiment, the unloading means are provided in side walls of a rotary, positive displacement, gas compressor, and in an alternate embodiment the unloading means are disposed within end walls (of a rotary, positive displacement, gas compressor), and comprehends means for step-control of a plural-stage machine.