Hydraulic tool clamping element - has pressure only on narrow shoulder of indicator plunger to allow use of small compliant return spring

摘要

The hydraulic tool clamping element is self-contained in a housing (1) fastened to the rotating spindle of the machine. A screw (3) exerts a force on the piston (5) to produce a desired pressure in the oil-filled pressure chamber (2). Sliding through two fixed seals (11,12) of a stepped bore (7) is an indicator plunger (6). Between the seals the indicator plunger has a small shoulder (9) which serves to move it against an opposing return spring (10) when oil pressure rises in the space between the seals. There is a passage connecting this space to the pressure chamber (2). The distance the tail (8) of the indicator plunger protrudes through the housing measures the oil pressure and hence the clamping force. USE/ADVANTAGE - Compact dimensions. Movement of plunger is great enough to permit easy reading. Oil loss through seals is minimal.