The invention relates to a pick locking device for a plow pick with a pick shank that can be inserted into an receptor box of a pick holder, with a retaining pin capable of being forced through an opening located on the face of the pick shank into a locking groove that runs in the direction of insertion along one side face of the tool shank, where a deformable plastic clamp element with two legs positioned at an angle to each other is provided in order to secure the retaining pin in its locking position, and where the one leg of the plastic clamp element is inserted into a retainer in the pick shank and the other leg inserts into a corresponding locking recess formed on the retaining pin. The invention particularly relates to the clamp element for such pick locking device, consisting of a deformable plastic material and including two legs positioned at an angle to each other of which one can be inserted into a retainer in the pick shank and the other is designated for engaging in a locking recess on the retaining pin, as well as a retaining pin for the pick locking device.
The generic pick locking device known from DE 297 07 967 U1 employs a one-piece plastic profiled elbow which has a groove with open edges running along the rear of both legs that is inserted into a corresponding profiled elbow holding device in the pick shank so that said elbow grips and clamps the retaining pin on both sides with both of its legs, i.e., on the bottom groove and on the side groove. In this known pick locking device, the elbow holding fixture consists of a trough-shaped recess into which the elbow clamp element is inserted. At the same time, the elbow clamp element inserts into a locking recess which runs around the perimeter of the retaining pin in the form of a groove, thus securing the bolt against accidental unlocking. Both legs have a convex cross-section and the cross section of the groove at the rear or both legs is made with a concave cross-section in order to achieve the required elasticity of the clamp element. The pick locking device known from DE 297 07 967 U1 generally fulfils its purpose satisfactorily, however, due to the complicated shape of the profiled elbow clamp element and the corresponding recess in the tool shank is comparatively difficult to realize and is relatively expensive.
DE 298 03 944 U1 proposes a split clamp element design with separate elastic chuck pieces, positioned at an appropriate distance from each other and held in holding fixtures in the pick shank that are arranged at a corresponding distance; here, the one elastic chuck piece on the inner groove flank and the other on the groove bottom projects into the locking groove of the pick shank against the retaining pin. In this instance, both the elastic chuck pieces are made as clamping pins in the form of sleeves and/or as solid material pins, preferably comprised of plastic.