Pivot angle adjusting means for the arm of a material handling device

Claim 1

Pivot angle adjusting means for the arm of a material handling device comprising: (a) an arm mount for holding an arm; (b) a support which supports the arm mount; (c) a rotary shaft which is rotatably mounted to the support, (d) a cylindrical vane chamber having a rotary vane, mounted to the support, in which the rotary vane secured to the rotary shaft is adapted to be pivoted by a fluid supplied to the cylindrical vane chamber; (e) a stopper mounted by means of a spur wheel having upper and lower peripheries, to the rotary shaft below said rotary vane; (f) a pair of sensors mounted to the support, and which are actuated by a pair of further stoppers for detecting the pivot angle of the rotary shaft; (g) a stop having a U-shaped mounting piece being mounted to the support and being movable a certain distance in the direction of the movement of the stopper, and said stop being adapted to be placed in the locus of the movement of the stopper so as to stop the stopper at a certain intermediate point which is the same point within the pivot movement of the stopper when the stopper is pivoted clockwise or counterclockwise; said stop being adapted to be movable a distance equal to the sum of the thickness of the stopper and double the thickness of said stop; and (h) and wherein said stopper comprises a mount piece of substantially U-shaped cross section, and having end bent upwardly and downwardly so as to engage in a periphery of flanges formed in said upper and lower peripheries of said spur wheel, a toothed piece having teeth engageable with teeth of said spur wheel in its inner end and having a tapered outer end surface facing a lower skew or slant, a wedge piece positioned between said toothed piece and the outer end of said mount piece, having a tapered inner end surface which faces an upper skew or slant and contacts with said tapered outer end surface of said toothed piece, and adjustable screw means mounted to the lower part of said mount piece, for pushing up on the bottom of said wedge piece.