Improvements in or relating to demonstrating apparatus

摘要

738,502. Educational appliances. ROLLSROYCE, Ltd. Oct. 28, 1953 [Oct. 29, 1952], No. 27245/52. Class 146(2). A demonstration apparatus for use in illustrating the principles of screw-cutting on a lathe comprises a pair of spindles 16, 25, one, 16, being screw threaded (16a) for longitudinally moving a block 15 which carries a writing instrument holder 21, 22, while the other 25 carries a drum 31 having a surface capable of being inscribed by the writing instrument or arranged to detachably support a sheet 32. The two spindles are interconnected by gearing 18, 36, 27 and turned by a handle 28. The intermediate gear 36 is replaceable to effect a different gear-ratio between the spindles 16, 25, the shaft 37 carrying it being adjustably fixed in an arcuate slot in a carrier 38. An electrical circuit comprising a lamp 44 gives a warning when block 15 reaches a selected position. The drum may be illuminated from within.