Abstract: A mitre box has an integrally formed synthetic resin support member which includes a platform portion, a corner post with right angularly disposed faces, a pair of clamp posts spaced from the corner post and a saw guide post disposed between the clamp posts. The corner post has a transverse channel bisecting the 90.degree. angle defined by its vertical faces, and the saw guide post has a channel aligned therewith so that a saw blade may be guided when seated in these two cooperating channels to effect a 45.degree. cut in a workpiece abutting one of the vertical faces of the corner post. Clamp assemblies are adjustably mounted in the clamp posts and include elongated members which are adjustably moveable therein relative to the cooperating vertical faces of the corner posts.

Abstract: A cutting and abrading hand tool is provided with a blade holder of generally rectangular shape and provided on opposite external side walls with parallel longitudinally extending outwardly facing grooves. Interchangeable and disposable blades of tubular form are provided which have various cross-sectional configurations and which have a longitudinally extending slot therein defined by inwardly extending flanges dimensioned to have a slip fit with the grooves of the holder. The holder is provided with abutments at either end of the grooves for securing the blades on the holder. The end portions of the holder having the abutments at one end of the holder are manually flexible inwardly to permit endwise removal and replacement of the blades.

Abstract: An improved case for a self-extending rule having a resilient blade which assumes a straight position when in a relaxed state and has a pair of case sections formed with flat top, bottom, and back walls, and arcuate side walls enclosing a cylindrical interior chamber and with a front wall having a generally arcuate opening in a lower sector thereof defined by the rim of the adjacent side wall and the edge of a reentrant web extending from the opposite side wall. The underside of the web has a center post extending into the chamber to mount a cylindrical cup for nesting the convolutions of the blade when inserted endwise through said arcuate opening and underneath the edge of the web. A brake is mounted for rectilinear movement in a radial opening in the top wall of the case adjacent the front side of the cup and is biased into engagement with a converging open rim of the cup.

Abstract: A holder for nails and the like includes a pair of operating members with pivot means biasing the jaw portions of the operating members into normally closed position and with the handle portions being movable towards each other to open the jaw portions. The jaw portions have vertically extending inner side faces and inclined outer side faces tapering from a reduced cross section at the top faces thereof to a broad cross section adjacent the bottom faces thereof. The outer side face of at least one jaw portion may have measuring indicia spaced along one portion of the length thereof, and the pivot means and operating members are desirably integrally formed. To limit the amount of pivotal movement of the operating member handle portions, stops are provided thereon which project towards each other and which are spaced apart a predetermined limited distance in the normal position of the holder.

Abstract: Sets of lamps arranged in adjacent opposed arrowhead configurations with each lamp energized by means of individual switching transistors having base drive voltages coupled through a multi-position switch to timing signals. The timing signals are generated by sequentially actuated flip-flops energized in response to impulses from a master clock and gating circuitry. Opposite directions are indicated by selectively energizing three sets of lamps forming three adjacent arrowheads, sequentially, in one direction, three similar sets in another direction, or by steadily illuminating one set of lamps forming an arrowhead while sequentially energizing lamps forming a shaft.