Servo Hemming Press

Abstract

Servo hemming press includes a direct drive system powered with a centrally located common planetary gear servo drive. A pair of connecting rods can actuate a slide vertically up and down to close the hemming tools and can perform the desired hemming operation. A planetary gear box preferably with dual output shafts is directly coupled to the crank shafts through couplings. The bottom end of the connecting rod can be connected to a pivot pin block that is secured to the base of the press. A spring-type overload protector can be incorporated between the base and the pivot pin block to protect the press from possible overloading beyond the rated tonnage capacity. The desired torque to deliver the rated tonnage to perform the hemming operation is delivered directly by a servo motor connected to the planetary gear box, thereby eliminating a flywheel and clutch of earlier systems.

1 . A mechanically driven hemming press comprising:
 a direct drive system including a planetary gear box connected to a servo motor that delivers force to perform hemming.   
     
     
         2 . The mechanically driven hemming press of  claim 1  wherein the planetary gear box and the servo motor form a planetary gear servo drive that is centrally located. 
     
     
         3 . The mechanically driven hemming press of  claim 1  wherein the planetary gear box has dual output shafts each coupled to a crank shaft, the hemming press lacking a flywheel or a clutch unit. 
     
     
         4 . The mechanically driven hemming press of  claim 1  wherein the servo motor only uses power during stamping operations. 
     
     
         5 . A hemming press supported on a base adapted for hemming two preformed sheet metal panels by bending the edges and pressing to hold together to form hemmed panels, the hemming press comprising:
 a servo motor connected to an input shaft of a planetary gear box;   the planetary gear box having an output shaft connected to a crank shaft;   an oscillating connecting rod with a top end connected to the crank shaft and a bottom end pivotably connected to the base to move a slide relative to the base;   the slide associated with the crank shaft wherein rotary motion of the crank shaft drives the slide through a connecting rod;   a top hemming tool attached to the slide; and   a bottom hemming tool supported by the base of the press;   wherein desired torque to deliver the rated tonnage to perform the hemming is delivered directly by the servo motor.   
     
     
         6 . The hemming press of  claim 5  wherein the planetary gear box has dual output shafts in a direct drive twin crank shaft system. 
     
     
         7 . The hemming press of  claim 6  wherein each output shaft is connected to the crank shaft through a coupling and a connecting shaft wherein motion is transmitted from the servo motor to the planetary gear box and then to the crank shaft through the coupling and the connector shaft. 
     
     
         8 . The hemming press of  claim 5  wherein the slide is designed to withstand rated tonnage of 120 tons and the slide supports the top hemming tool. 
     
     
         9 . The hemming press of  claim 5  wherein the crank shaft can rotate at a speed of 8 rpm. 
     
     
         10 . The hemming press of  claim 5  wherein the base supports a pivot block into which a bottom end of the connecting rod is fitted with a pivot pin and a bush bearing. 
     
     
         11 . The hemming press of  claim 10  having a second bush bearing fitted on to the slide and third bush bearing on top of the connecting rod, wherein the bush bearings are made of laminate composite bearing materials with high load capacity and low friction surface. 
     
     
         12 . The hemming press of  claim 6  wherein a pair of connecting rods actuates the slide vertically up and down to close the hemming tools and perform desired hemming. 
     
     
         13 . The hemming press of  claim 6  further comprising a pair of counterbalance cylinders, a set of four guide post structures, a set of four guide rods, and a pair of pivot blocks. 
     
     
         14 . The hemming press of  claim 13  wherein a spring-type pressure compensator is incorporated between each pivot block and the base to safeguard the press from overloading. 
     
     
         15 . The hemming press of  claim 5  wherein the slide is guided with gibs fitted with replaceable wear liners. 
     
     
         16 . The hemming press of  claim 5  wherein further comprising a pneumatic counterbalance cylinder to counterbalance weight of the slide and the top hemming tool. 
     
     
         17 . The hemming press of  claim 5  wherein the servo motor only uses power during stamping operations to reduce energy consumption. 
     
     
         18 . The hemming press of  claim 5  lacking a flywheel or a clutch unit.