Patent GB-168207-A (GB)
Title: Improvements in or relating to scleroscopes
IPC: G01N3/52
Filed: 1920-06-26
Abstract: 168,207. Wade, H., (Schuchardt & Schutte). June 26, 1920. Testing hardness by rebound of hard body.- Comprises a scleroscope in which the guide for the falling hammer is prismatic, preferably, threesided, the third side being transparent, and a driver device for returning the hammer. In the form shown in Figs. 1 and 3, the guide tube is .of triangular section closed on the third side by a glass plate 11. The hammer a is cylindrical and has a line-bearing on each of the three faces of the guide. The hammer is held up by the lower end of catches b<1>, b<2> engaging a recess therein. A spring 14 bears between inner and outer thimbles 32, 33 both having conical recesses at the lower ends which are adapted to engage projections on the upper ends of the catches. Normally the inner thimble keeps the lower ends of the catches apart. When the outer thimble 33 is depressed, the lower ends of the catches are pressed towards each other and the hammer is released. Independent means are employed for returning the hammer. The back of the body of the tube d is grooved to receive a rod c surrounded by two springs 24, e, the first one bearing between an abutment guide 18<1> and a plunger 34, while the second bears between an abutment guide 18<2> and the head of a driver h which loosely surrounds the rod c. A lug g on the lower end of the driver projects under the rod c and a second lug 23 projects into a slot formed in the corner of the hammer guide. Normally, the projection 23 is out of the .path of the hammer, but on depressing the plunger 34, both springs are compressed and the driver h moved down. A cam 36 on the lower end of the driver engages a cam 37 and the lower end of the driver is moved laterally into the hammer path and at the same time disengaged from the rod c, whereupon the spring e returns the driver and hammer, the driver being moved out of the path of the hammer at the end of the stroke by the engagement of a cam 35 with the edge 22<1> of the slot. The spring 24 returns the plunger. In the second form shown in Figs. 7 and 14, the tube carries an arresting device comprising a cage 43 carrying balls 42 which engage the rod a' of the hammer, and also a conical guide 41. The cage has a slight vertical movement limited by collars 45 and is retained when moved to the upward or downward limit by a spring friction ring 46. In the lower position of the cage, downward movement of the rod a<1> is prevented, while on the upper position free downward movement of the rod is permitted. The cage is moved automatically by flanges a<3>, a<4> on the ends of the hammer, the top of the rod being thinned so that the hammer can move downward slightly after the flange has engaged the cage. The catch b is depressed against a spring plunger 33 to release the hammer, which is returned by depressing a piston 51 against a spring 24, air being compressed in a tube 49, the pressure acting upon a piston h, a lug 23 on which engages the flange a<2> and returns the hammer. Release of the piston causes a vacuum which, together with the weight of the piston h, causes the return of the latter.