A method for controlling proper clamping of a workpiece in a clamping device, the clamping jaws of which are moved to a clamping position by movement of a piston of hydraulically operated cylinder-and-piston means in a clamping direction, in which a control signal is produced indicating proper clamping of the workpiece when sensing means cooperating with the piston indicate that the latter, during its movement in clamping direction, has reached at least a first position but not reached a second position spaced in clamping direction from the first position, while at the same time a predetermined pressure acting in clamping direction on the piston is indicated.
A stroke first air cylinder mechanism having a larger-diameter first piston and a larger-diameter first rod is incorporated in a casing, a chuck second air cylinder mechanism having a smaller-diameter second piston and a smaller-diameter second piston and a smaller-diameter second rod is coaxially incorporated into the first air cylinder mechanism, a base end portion of the second rod projects from the first piston and extends to such a position as to face a position detecting portion of the casing, a magnet is mounted to the base end portion of the second rod, and magnetometric sensor is mounted to the position detecting portion. By detecting an operating position of the second rod, opening and closing positions of jaw members can be detected.
A clamping device, for use for example for clamping a tool or workpiece in position in a machine tool comprises a clamping anchor to which a clamping force is applied by a hydraulically operated cylinder. The device also includes a screw operated compensating or back-up unit which acts on the piston of the hydraulic cylinder. The compensating unit is driven by the same hydraulic system as the hydraulic cylinder and when the piston has been moved hydraulically to apply the clamping force to the anchor, a screw component of the compensating unit moves into engagement with the piston to lock the piston in position and maintain the clamping force even if the hydraulic pressure on the piston is then released.
The present invention relates to a method and apparatus for determining a working range of a double-acting clamping cylinder for actuation of operating devices, such as supporting, centering or chucking devices, respectively on machine tools, particularly replaceable chucks on lathes, giving consideration to a post-tightening distance and controlling of the drive for effecting of the machining of the workpiece. In order to avoid a replacement of control cams or adjustment of limit switches of the prior art, the total path of the clamping cylinder is monitored by a length-measuring instrument which gives off electric pulses to a control device which determines the total stroke of the corresponding supporting, centering or clamping device and stores in the control device the end positions thereof lying within the total path of the clamping cylinder within and, with due consideration to the post-tightening stroke associated with the corresponding operating device, determines the working range of the clamping cylinder for the respective operating device outside of which working range the drive for effecting the machining of the workpiece is blocked by the control device.
A process for preparing and cooking corn dogs which are batter coated weiners upon a stick has a fry tank and coating bin mounted on a frame. Food articles are impaled by sticks driven through clasps in slots in a stick clamp. The food articles are dipped into a coating substance by elevation of the coating bin. The articles are elevated by rotating or flipping them above the lip of the fry tank and immersed in hot grease within the fry tank, cooked, and then elevated by rotating or flipping them out of the fry tank. The sticks are unclasped from the stick clamps and placed on a receiving tray. Thermostatically controlled heating elements suspended above the floor of the tank heat the grease.
