Abstract: A power section and a converter section are disposed in end-to-end, tandem relationship. Linear motion imparted by the power section to a captive nut in the converter section propells the nut along the spiral flutes of a drive shaft rotatably journalled in the converter section, thereby converting the linear motion of the nut to rotary motion of the drive shaft.

Abstract: A microscope drape fabricated from a very thin, transparent, heat-resistant plastic film which is adapted to completely house an operating microscope including its support arms, is provided with an improved tubular ocular housing extension, the free outer end of which terminates in a pull tab which serves not only to facilitate positioning of said tubular portion over an ocular, but also to facilitate removal of said pull tabs whereby to accurately and effectively position the free outer end of the ocular housing extension remaining after removal of the tab portion closely adjacent to the outer ends of the eyepieces of the oculars.