Animal-ear-marking tool - has housing with fixed and hinging handles, with movement of hinging handle transmitted to perforation pin via spring biassed hinging pawl

摘要

The tool inserts an item in a body, being for earmarking animals etc. It has a housing with fixed and hinging handles, together with a component sliding to and fro in a straight line, e.g. a perforation pin. Movement of the hinging handle is transmitted to the latter via a hinging pawl acting against its end, there being a spring between the handle and the pawl. A first lug on the hinging handle presses the spring in to a stable position from which it is thrust by a cam on the housing at the end of the pin stroke. First, second and third return springs thrust the pin into a stable retracted position, and the handle and pawl into similar positions defined by stops in the housing. The pawl is a single lever (7) with constant velocity ratio, and is so designed that with a constant angular velocity of the hinging handle the pin speed increases as it moves out of the rest position.