Abstract: A mail box signal device article is adapted for ready installation to a street mail box. The article comprises a housing for holding the components of the device, with the housing itself attached to the mail box. Mounted on the housing is a hub assembly comprised of an axle which extends through a side wall of the housing, a first disc rotatably mounted on the axle within the housing and a second disc rotatably mounted on the axle outside of the housing. The two discs rotate together. An arm extends from the first disc and has a lateral pin extending at a right angle from one extremity. A slide link with an elongated slot is slidably connected with the lateral pin of the arm. A bracket pivotably attached to one extremity of the slide link is intended for permanent mounting to a door of the mail box. A signal is fixedly attached to the second disc of the hub assembly. The signal is moved to a vertical position when the door is opened and remains there until disengaged by the owner.

Abstract: A two-stage pump which includes a pair of reciprocating pump members operating in opposed pump chambers and a connecting rod connecting the pump members to cause the pump members to operate in unison. Air under pressure is supplied to the chambers by a spool valve member which operates in a guide sleeve. The spool valve includes four outwardly extending portions defining a central pressure slot and a pair of exhaust slots. Ports in the sleeve communicate with the pump chambers. The spool valve is moved by pressure in pressure chambers at opposite ends of the sleeve member. The sleeve is mounted in a bore, and metering air passageways are formed between the valve sleeve and the bore and connecting the pressure chambers with the exhaust slots.