Abstract: A battery powered grass shear having improved upper and lower shear blades with improved cutting and durability characteristics and which require less power to operate. The lower shear blade, which is fixed to the housing of the battery powered grass shear, is provided with a forwardly and upwardly extending forward portion provided with transversely spaced apart cutting teeth. The upper shear blade, which is reciprocated relative to the lower shear blade, is formed of a comparatively thin, heat treatable, resilient steel and is normally flat when in a non-stressed state. The upper blade, when assembled to the lower blade is bowed upwardly and the cutting edges of the spaced apart teeth on the upper blade intersect the cutting edges of the spaced apart teeth on the lower blade and make point to point contact throughout the length of the blade as the blades are reciprocated. The cutting surfaces are preferably heat treated to an equal hardness.

Abstract: An improved cooling system wherein printed circuit cards are made into modules of two cards each with an enclosed space between them inside the module. The modules cooperate with a rack which carries air passages, and upon connection of the module into the rack, air flows from one side of the rack through the module space, thus cooling the cards from their rear surfaces, thence out of the module, and returned via the other side of the rack.

Abstract: Cordless electric tools or the like comprising a power handle and a plurality of diverse tool heads detachably securable thereto. The power handle includes battery means therein and operator controlled switch means, whereas each of the diverse tool heads may include an electric motor and an output means. The tool heads and power handle include interengageable means constructed for quick mechanical and electrical interconnection therebetween facilitating quick connection and disconnection of the power handle from the various tool heads without requiring any special tools or implements. Electrical interconnection is made automatically upon mechanical interconnection. In addition, a battery charger for the battery means may include similar mechanical and electrical connection means operatively engageable with the power handle to afford ready and easy charging of the battery means between uses of the power handle.

Abstract: An improved system of pitch control for aircraft having a "flying tail"; i.e., a movable horizontal stabilizer with at least one movable elevator thereon. The human or automatic pilot input commands operate the elevators, and then the elevator response is used as part of the command to operate the stabilizer.

Abstract: A compact, portable electrical discharge metalworking machine for off-hand use and general applicability. The invention is a lightweight, versatile gun type tool which has air and water cooling of electrode and work, a vibrating electrode to facilitate its motion inside the work, a simple, automatic, spring driven, all orientation electrode feed, and uses low voltage, high amperage electricity.

Abstract: A system for mounting two bearings on a single shaft to achieve self-alignment without spherical bearings. The invention system comprises a cast-in convex curved seat which cooperates with resilient hold down means, whereby the bearings are protected from damage by the force of assembly while the system is substantially self aligning.

Abstract: An improved air reversing valve, as for use with a pneumatic scaler, chisel or the like, comprising throttling means between the two sides of the valve disc whereby the tool's performance characteristics are generally improved. Additionally, the valve is made multi-element whereby its manufacture is simplified, as by powdered metal casting internal passageways in facing surfaces of adjacent parts, rather than cross drilling or the like.

Abstract: An improved shifter mechanism for the transmission of a power tool in which the operating lever can be located to either side of the transmission housing. The operating rod has a flat which operates one end of a pivoted shift member, the other end of which moves a clutch member to engage or disengage a rotation clutch. The shifter provides positive action, a long throw, and permits operation in either direction. The clutch itself includes an improved lubrication feature and improved mounting of the fixed clutch member to the armature shaft.

Abstract: A dust cap particularly for use with an overhead rotary hammer. The dust collector is a cup-like member with a bellows side wall, integrally formed in one piece. It has a thickened neck to fit on the tool shank below the chuck, thereby encompassing the chuck and the lower end of the anchor. Dust is efficiently caught in that the bulk of the dust passes through the anchor and chuck, and then directly into the dust collector cup, plus most of the dust outside the anchor is also caught as it falls around the anchor. The bellows side wall facilitates changing tools and removing anchor ends.

Abstract: A sharpener having a clam-shell housing in which a motor is mounted for driving a grinding wheel disposed adjacent one end of the housing, a chuck which holds either twist drills or a diamond dresser, the chuck being indexable 180.degree. about its axis, and structure for mounting the chuck relative to the grinding wheel so that either the twist drill can be moved in a prescribed manner across the grinding periphery of the grinding wheel, or so that the diamond dresser can be moved across the grinding wheel in order to dress the wheel to a form suitable for sharpening twist drills or the like, and also means for moving the twist drills or the like or diamond dresser towards the grinding wheel.