Abstract: A pressure-driven engine is provided therein with an intake valve and an exhaust valve the opening and closing operations of which are controlled by a combination of the urging force of the respective springs and the attractive force of the respective magnets. The engine automatically repeats reciprocating motion merely by supplying a pressure source such as steam or various kinds of compression gas. The reciprocating motion or the rotational motion converted from the reciprocating motion is utilized as a power.

Abstract: A fingertip exerciser comprising two balls each having a bore extending centrally therethrough and a connector inserted through the bores of the balls and rotatably connecting the balls together. The faculty of the fingertips can be developed by rotating the two balls with the fingertips.

Abstract: A hose connecting mouthpiece comprising an insert having a rear end to be connected to the hose of a gas filling device, a union nut loosely fitting around the insert and having an internally threaded portion engageable with the externally threaded portion of a known nipple, a packing attached to the front end inner periphery of the insert and adapted for contact with a sealing face at the forward end of the nipple, and a valve core pushing member provided inside the insert and retractable into the insert by being pushed by the forward end of the valve core of the nipple. The mouthpiece is fittable to any one of three types of known nipples different in construction.