Abstract: An improved rotary impact clutch or impact wrench of the type normally used for setting threaded fasteners by imparting rotary impacts. The combination includes a hammer member which is driven; an anvil to which the rotary impacts are delivered. Pins which may be referred to as dog pins or anvil pins are carried in axial recesses on the inside of the hammer member and are movable axially against the force of a spring to come into position to deliver impacts against lobes of the anvil member. Ball cam means are provided associated with a cam sleeve which has engagement with the dog pins for the imparting of the axial movement to them. The dog pins or anvil pins are generally cylindrical, having an intermediate part of smaller diameter. The improvements reside primarily in a further component preferably in the form of a ring, shaped to be positioned inside of the hammer and having diametrically opposed recesses to engage the end parts of the dog or anvil pins.

Abstract: A centrifugal air compressor having first and second stages together with means for recirculation, at a predetermined low level of flow, air of compression from the second stage simultaneously to the inlet passage of the rotor of the first stage and to the discharge passage of the rotor of the first stage in such manner that the injected air is admitted tangentially to the inlet passage and in the direction of the prevailing flow to the discharge passage, with the result of improved flow stability through the compressor being obtained.