US 2003/0163923 A1Published application

Shear-locking device

AssigneeWolf-GmbH & Co.KG

InventorsManfred Schneider, Gerhard Staudt

Life of this patent

Estimating the term…

Loading patent…

Abstract

The invention relates to a locking device, especially for anvil shears, ensuring closure of the shear free from any light gap and irrespective of manufacturing tolerances and wear. A pivoting tumbler (24) fitted with a cam surface (34) and interacting with a corresponding cam surface (32) of the other limb (14) of the shear is actuated by the force of an opening spring (20) into closed position (10). The arrangement operates in such a way that the cam surfaces interact in a self-locking manner when continuously pivoted in the closing area and the tumbler may be moved to an end position when the limbs of the shear are progressively closed thus ensuring a final closing position. The cam surfaces (34) of the tumbler interacting with a cam surface (32) of a catch groove (28) can have a larger configuration in the direction of closure. Due to technical manufacturing reasons, an arched cam surface may also be provided, which is eccentrically located in relation to the pivoting axis of the tumbler. The tumbler is pivoted by a slide button (22) which slides in a linear guide of the shell of the handle. A fine locking device (50) is provided between the slide button and the guide ensuring that the slide button may be fixed in different closed positions and preventing unintentional closure in the opening position.

Claims10

Dependent claims

Pruning shears comprised of:

first and second crossed pivoted limbs (10, 14) which carry respective cooperating cutting elements (12, 16) at the front ends thereof, and which extend rearwardly to form hand grips for operating the shears;
a spring (20) that cooperates with the limbs (10, 14) to apply a force tending to open the shears;
a locking device, the locking device comprising:
a manually operable slide button (22);
a tumbler (24) which is pivotally mounted on the first limb,(10) and which is coupled to be moved by the slide button in a first direction to lock the shears in a closed position against the force of the spring (20) with no gap between the cutting elements, and in a second direction to a released position at which the shears may be manually opened and closed;
a cam surface (34) on the tumbler;
and
a latching cam surface (32) on the second limb (14) that interacts with the cam surface (34) on the tumbler, the two cam surfaces being so shaped and located that, when the shears are locked in the closed position, the tumbler is prevented from moving in the second direction, thereby to provide self-locking,
at least one of the cam surfaces being sufficiently extended to allow the tumbler to move far enough in the first direction to lock shears in the closed position, and to maintain self locking, independent of wear, adjustment or manufacturing tolerance in the shears.

6 more elements

Dependencies are inferred from the claim text.