Views: 26 Author: Site Editor Publish Time: 2017-02-14 Origin: Site
In hitherto existing cutting machines with an oscillating knife and a so-called material presser foot mounted on a carrier bar which extends in the longitudinal direction of the knife and is displaceable in this direction at the housing, a clamping device is normally mounted to hold the material presser foot at a certain level once it has been raised. Pivoted at the housing is a lever with which the clamping device can be released, so that the material presser foot is made to fall down by its own weight either into its lower end position or during the cutting operation onto the uppermost layer of cloth or the like. The first disadvantage of these known cutting machines is that during operation the machine has to be held and the lever for the clamping device actuated by one and the same hand, and the other hand has to be extended in front of the oscillating knife to grasp and lift the material presser foot, so not only are both hands required for operation, but, in addition, one hand has to be extended into the danger area around the oscillating knife.
When curves and corners are cut in a pile of material by a cutting machine with an oscillating knife, the material becomes warped in the region of the oscillating knife. In the case of normal materials, artificial leather and the like, the material presser foot, made to rest on the material to be cut by its own weight when the clamping device is released, is raised by this material. However, if very light fluffy materials are cut, the latter are not able to raise the material presser foot, which makes it more difficult to cut narrow curves and corners.
In a cutting machine with an oscillating knife comprising a motor mounted in a housing for driving a lengthwise oscillating knife extending in a substantially vertical direction, further comprising a material presser foot mounted on a carrier bar extending in the longitudinal direction of the knife and displaceably guided in this direction at the housing, and further comprising an actuating member mounted at the housing to release a support means for the carrier bar, these disadvantages are eliminated in accordance with the invention, in that the actuating member is also coupled with a lifting device for lifting the carrier bar in a stepwise manner. This stepwise lifting is easiest to achieve by a transportation member actuated by the actuating member frictionally or positively engaging the carrier bar. This results in a cutting machine with genuine one-hand operation eliminating contact with the danger area around the oscillating knife and during the cutting of narrow curves and corners the material presser foot can be raised by a very precise amount in the simplest way.