| 摘要 |
A hydraulic stretching device for a saw chain active in sawing apparatus having a saw bar and including a holder (1), a driving wheel (3) for the saw chain arranged essentially stationary in relation to the holder and a guiding part (7) permanently arranged at a saw bar to interact with the holder (1). The guiding part (7) is permanently attached to resist turning and axially displaceable in relation to the holder (1) in the longitudinal direction (8) of the saw bar to allow stretching of a saw chain running round the saw bar (6) and the driving wheel (3). The stretching device for a saw chain is arranged to be active between the holder (1) and the guiding device (7) and including a hydraulically influenced piston (10). The piston (10) is arranged in a displaceable manner at the holder in parallel with the longitudinal direction (8) of the saw bar and has an engaging surface (11) intended to engage an opposing surface (12) on the guiding part (7). The engaging surface and the opposing surface are located in parallel planes and that these planes are arranged at an angle to a plane perpendicular to the longitudinal axis of the saw bar. In this way, the piston (10), when it engages the surfaces, affects the guiding part (7) with a force F whose components act partly in the longitudinal direction of the saw bar (Fs) to stretch the saw chain and partly in a direction across the longitudinal direction of the saw bar (F8) to achieve a stabilizing gripping of the parts that move in relation to one another. In addition, a compressible mechanism (13,14) is arranged to engage between the piston and the guiding part before the engaging and opposing surfaces engage one another, whereby an initial stretching of the saw chain is achieved before the combined stretching and gripping effect is realized. |
