Text version of the page

1. Safety instructions and guidelines for the use ofpower-operated clamping devices

To ensure a safe operation of power-operated clamping devi-ces, particularly of chucks, on heavy-duty lathes with highspeeds certain criteria must be observed:1.When mounting the power chuck and the actuating cylin-der on the lathe, the following saftey requirements mustbe met:1.1The machine spindle may only start when the clam-ping pressure has been built up in the actuating cylin-der and the clamping has been carried out the permis-sible working area.1.2Unclamping may only be possible when the machinespindle has completely stopped.1.3In case of a clamping energy failure, the workpiecemust be firmly clamped until the spindle is completelystopped. (The Röhm safety cylinders meet this requi-rement).1.4In case of a current failure and upon return of the cur-rent supply the actual control position may not bechanged.1.5In case of clamping energy failure the machinespindle must be stopped by a signal.2.The safety instructions given in the respective operatingmanual must be precisely followed.3.After having mounted the chuck and before starting theoperation the function of the chuck must be checked.Two important points are: 3.1Clamping Force! The clamping force ( ± 15%) stated for the clamping device must be reachedat max. actuating force/pressure. 3.2Stroke control! A safety range must be provided forthe stroke of the actuating piston in the front and rearend position. The machine spindle may only start afterthe actuating piston has crosssed the safety range.Only limit switches meeting the requirements for sa-fety limit switches in accordance with VDE 0113/12.73section 7.1.3 may be used for monitoring fthe clam-ping path.4.If the max. speed of the lathe exceeds the max. speed ofthe clamping device or actuating cylinder, the machinemust be equipped with a speed limitation device.5.When the clamping device has been changed, the strokecontrol must be adjusted to the new condition.6.When calculating the required clamping force for machi-ning a workpiece, the centrifugal force of the clampingjaws must be considered (information for calculating therequired clamping force are contained in the end of theRöhm catalogue product group 6).7.A reliable operation of the power chuck can only be gua-ranteed when the mainenace instructions contained in theinstruction manual are precisely followed. In particular thefollowing points must be observed:7.1For lubrication only the lubricants recommended in the operating manual shall be used. (An unsuitablelubricant can reduce the clamping force by more than 50%). 7.2The lubricant must reach all surfaces to be lubricated.(At the narrow fits of the mounting parts a high pres-sure is required for pressing in the lubricant. For thisprupose a pressure gun must be used.)7.3In order to distribute the grease evenly, move theclamping piston several times to its end positions,repeat the lubrication and then check the clampingforce.8.Before restarting a serial machining operation and in bet-ween the maintenance intervals the clamping force shouldbe checked by means of a load cell. ”Only regular checksensure optimum reliability”.9.It is recommended to move the clamping piston severaltimes to its end positions after 500 clamping strokes at thelatest. (In this way any lubricant pushed away will be retur-ned to the pressure surfaces. The pressure force is thusmaintained for a longer period of time).10.When using special clamping jaws the following instruc-tions must be observed:10.1The clamping jaws should be designed in such a waythat their weight and height is as low as possible. Theclamping point should possibly be close to the frontside of the chuck. (Clamping points at a larger di-stance may cause a higher surface pressure in thejaw guiding mechanism and may thus reduce theclamping force considerably).10.2In case the special jaws are for contructional reasonswider and/or higher as the step jaws assigned to theclamping device, the resulting higher centrifugal for-ces must be considered when calculating the requi-red clamping pressure and the rated speed.To determine the permissible speed for a certain track, please refer to page 12, section 9.To determine the actual gripping power, we shouldlike to recommend the use of our electronic grippingpower measuring system EDS. The EDS measuringsystem allows you to measure the gripping power ofthe idle and the rotating chuck. It is thus excellently suited for recording changes of the gripping powerdue to the centrifugal force of the jaws.10.3Welded models should possibly not be used. If requi-red, the welding seams must be checked as to theircentrifugal and clamping force capacity.10.4The mounting screws must be arranged in such a way that the highest possible useful moment is re-ached.11.The max. speed may only be used at max. applied actua-ting force and with properly functioning chucks.12.In the case of high speeds the chucks may only be usedbelow a protective hood with sufficiently large dimensions.13.For power chucks with a jaw quick-change attachment inin the inside of the chuck a safety device is required whichprevents the machine spindle form starting when theclamping jaws are released.14.After a collision the clamping device must be checked forfissures before being used again.

9