Tool for tightening clamps

Claim 1

A tool for tightening clamps, of the kind comprising a flexible strip and an apertured head, having a passage in which the end of the flexible strip can be engaged after the strip has been passed around a bunch of articles to be clamped together and through the apertured head, the tool being used to cut-off that portion of the flexible strip of the clamp which projects beyond the apertured head following tightening to a greater or lesser degree of the clamp around the articles, the tool comprising a plate having a transverse portion at one of its ends formed to define an intake opening to receive said portion of the flexible strip of a clamp and at the other of its ends a fixed grip; a displacement member mounted for movement longitudinally of said plate and including means capable of gripping said portion of a clamp; a trigger pivotally mounted on said plate for movement relative to said fixed grip; coupling means including a swinging link provided between said displacement member and said trigger and including a release mechanism controlled by elastic calibrating means; a cutting lever pivotally mounted between a rest position where it leaves free said intake opening of said plate and a working position and with which are associated restoring means which draw said cutting levers in the direction of said rest position; said release mechanism comprising a cam having a cam surface with two separate stable zones separated from one another by an unstable zone and a cam follower maintained in contact with the cam surface of the cam by elastic calibrating means, said cam and said cam-follower being relatively movable within limits defined by said cam surface thereby to swing said cutting lever from said rest position into said working position, one of said cam and said cam-follower being fixed to said trigger and the other being provided on said swinging link of said coupling means provided between said trigger and said displacement member, said elastic calibrating means being coupled to said swinging link and said swinging link having engagement means engaged with complementary engagement means fixed to said cutting lever.