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.

What is claimed is: 
     
         1 . A mechanically vertically driven hemming press comprising:
 a direct drive system including a planetary gear box connected to a servo motor that drives a slide vertically and delivers force to perform hemming; and   a counterbalance cylinder to balance the weight of the slide.   
     
     
         2 . The mechanically vertically 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 and drives the slide vertically. 
     
     
         3 . The mechanically vertically driven hemming press of  claim 1  wherein the planetary gear box has dual output shafts each coupled to a rotating crank shaft. 
     
     
         4 . The mechanically vertically driven hemming press of  claim 1  wherein the servo motor only uses power during hemming operations. 
     
     
         5 . A hemming press comprising a counterbalanced vertically moving slide attached to a top hemming tool, which moves down and performs hemming operation by bending edges of sheet metal panels resting on a bottom hemming tool, which is vertically supported on a base,
 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 the slide vertically relative to the base;   the slide associated with the crank shaft wherein rotary motion of the crank shaft drives vertical slide motion through a connecting rod;   the top hemming tool attached to the slide; and   the bottom hemming tool supported by the base of the press;   wherein desired torque to deliver the rated tonnage vertically 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 to provide the vertical slide motion. 
     
     
         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 coupling and connector shaft to provide the vertical slide motion. 
     
     
         8 . The hemming press of  claim 5  wherein the vertically counterbalanced slide is designed to withstand rated tonnage of  120  tons delivered vertically and the slide supports the vertically balanced 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 vertically mounted pivot block in to 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 the vertically moving 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 vertically moving 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 vertically moving slide is guided with guide rods vertically guided in a guide post structure fitted with replaceable wear bushes. 
     
     
         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 hemming operations to reduce energy consumption. 
     
     
         18 . A hemming press comprising a counterbalanced vertically moving slide attached to a top hemming tool, which moves down and performs hemming operation by bending edges of sheet metal panels resting on a bottom hemming tool, which is vertically supported on a base,
 a servo motor connected to an input shaft of a planetary gear box;   the planetary gear box having a dual output shaft with each output shaft connected to a crank shaft in a direct drive twin crank shaft system to provide vertical slide motion;   an oscillating connecting rod with a top end connected to the crank shaft and a bottom end pivotably connected to the base to move the slide vertically relative to the base;   the slide associated with the crank shaft wherein rotary motion of the crank shaft drives vertical slide motion through a pair of connecting rods;   the top hemming tool attached to the slide;   a pair of counterbalance cylinders to counterbalance weight of the slide and the top hemming tool; and   the bottom hemming tool supported by the base of the press;   wherein desired torque to deliver the rated tonnage vertically to perform the hemming is delivered directly by the servo motor and wherein the servo motor only uses power during hemming operations.