"SPIETH designed" clamping sleeves are friction-locked connecting elements used in applications of general mechanical engineering. Arranged between cylindrical shafts and hub bores, they are capable of transmitting high torque levels and/or axial forces. Their high centring capability, dynamic symmetry and the ease of dismantling afforded by the use of spring hardened steel make them ideal for application wherever precise concentricity is called for, where high rotational frequencies are involved, or where exchangeable components require connecting. Typical application examples include the fixture of pressure rollers, shaft-hub connections to fast-running working spindles on machine tools, centric clamping of axially adjustable shafts, fixture of exchangeable profile rollers ets.
Following examples will give an overview of practical applications.
Example 1: Piston rod clamping. For safety reasons, the piston rod must be safeguarded following shutdown or hydraulic failure by clamping action. The clamping force for the clamping sleeve is applied by means of cup springs; the connection is released by oil pressure. Assembly: Preliminary assembly without cup springs. The shim ring is defined at the flange cover in such a way, that a slight axial pretension acts on the clamping sleeve in its non-tensioned state. The cup springs must not be pretensioned until the piston rod is inserted. Otherwise the clamping sleeve could be permanently deformed as a result of the applied clamping force.
Example 2: Tailstock sleeve clamping. The tailstock sleeve is hydraulically tensioned and precisely centred. Free movement is immediately possible in the untensioned state. The axial thrust occuring during the clamping process with single arrangement of a clamping sleeve is theoretically balanced out in this case by forces working in opposition. In practice, however, in case of a freely located tailstock sleeve, a slight residual thrust may be expected due to the impossibility of creating identical clamping conditions at the clamping sleeves.
Assembly: The height of the shim ring is defined during assembly in such a way that the tailstock sleeve can just still be moved when the flange cover is tightened. This restricts play in the joint between the housing bore, clamping sleeve and tailstock sleeve to the extent that the possible center displacement of the tailstock sleeve relative to the housing bore is minimized even in an untensioned condition.
Example 3: Swivel table clamp. Hydraulic clamping of the shaft in any optional position of the table. Without applied oil pressure, the shaft can immediately be freely moved again. The precisely centred clamp and the intensive end face contact of the swivel table guarantee maximum repeat accuracy. Assembly: The shim ring is defined in such a way that, when the flange cover is mounted, the assembly play between the clamping sleeve and shaft/housing bore is restricted sufficiently to alow the shaft to just still be turned. This ensures a high degree of repeat accuracy of the swivel table position.
Example 4: Blade wheel fixture. The clamping sleeves arranged over a wide basis exert a positive influence on axial centricity and rotating flexural stress of the shaft-hub fit. The degree of torque which can be transfered with two consecutively arranged clamping sleeves is ~30% higher than when using a single clamping sleeve. Assembly: After joining the individual components, the central clamping screw is tightened to a degree of torque corresponding to the required clamping force. The pin used as an anti-rotation element prevents the entire connection from loosening in case of unexpected excessive stress applied in the unscrewing direction of the clamping screw.
Example 5: Bevel wheel fixture. This connection is characterized by simple connecting components, a high degree of concentricity and absolutely freedom from play. Assembly: The bevel wheels are mounted and dismantled at the permanently mounted shafts. This is possible by placing the bevel wheels on the shaft before pushing the clamping sleeve between the shaft and hub bore. To dismantle, first the clamping sleeve is extracted before the bevel wheels can be removed.
Example 6: Fixture of a built-in spindle. With this type of fixture, the circular construction of the clamping sleeve and the reduced clamping force set by restricting the clamping path reliably eliminate the risk of deformation of the built-in spindle housing. Reproduction of the central position after every spindle change is guaranteed by the advanced centring capability of the clamping sleeve. The spring hardness of the clamping sleeves permits troublefree spindle change as often as required. Assembly: The arrangement of the shim ring restricts the occurring clamping forces irrespective of the screw tightening torque. The height of the shim ring must be adjusted in such a way, that the built-in spindle is reliably held but there is no risk of deformation. Clamping force is initiated in this case via a flange cover from one side. In view of the low clamping forces, the reduced retaining force for the rear clamping sleeve brought about by friction loss has practically no impact.
Example 7: Plug-in connections (Picture 9-11). These shaft-hub connections are completely free of play, and permit any optional number of mounting and release operations. The tightening torque levels for clamping force initiating screws depend on the required clamping force for each individual clamping sleeve.
