| 摘要 |
The cylinder unit (4) piston (5) is secured (6) to the lower shaft (2) of the pressure foot (3). Tubing (8) connects the cylinder to a pneumatic control system including a pressure regulator. This is equipped with adjustable stabilizing valves. Preferred features: The piston has an annular groove along its outer edge, accommodating a resilient O-ring seal, and is connected through a shaft to the shoe. The tubing is connected to the top of the cylinder and ends at the pneumatic control system, where a regulator controls pressure in the air circuit, to a high degree of precision. Control of the regulator is by means of a suitable pressure reducer and pressure stabilizing valve. The quantity passed by the valve is varied by a pressure regulator. An auxiliary compensating unit is inserted between cylinder and pressure regulator, to compensate small variations of pressure, before the pressure regulation valve comes into action. A second output may be installed low in the cylinder, with which a pneumatic auxiliary valve can be connected to assist lifting of the foot, when inserting or removing material. A parallel mechanical connection between compensating unit and shaft of the shoe is feasible.
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