Screwdriver for small precision screws - has plastics convergent lens in handle and focused on screwdriver blade to provide enlarged image (DK 24.10.77)

摘要

The screwdriver is used for precision screws, these being difficult to manipulate due to their small size. It has a plastics convergent lens (12) fixed in its handle, and the focal point of this lens lies at the top of the screwdriver blade (10). This provides and enlarged image of the blade area. There is an inscribed line on the lens which lies parallel to the plane of the blade. This blade is fixed into one end of a clear plastics stem (11), the other end being fixed in the face of the lens. The handle (13, 14) is a short tubular length of clear plastics enclosing the circumference of the lens.