US 6,182,492 B2Granted

Hemming machine

AssigneeE.R. ST. Denis Inc.

InventorsLouis Raffin, Dominique R. M. Baulier

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Abstract

A hemming machine of the type having a base, a nest for supporting a sheet metal part to be hemmed, and at least one die is disclosed in which the nest supporting the part to be hemmed is vertically displaced against the dies in order to form the hem. The improvement includes at least three elongated and external shafts wherein each shaft has one end rotatably mounted to the base so that the shafts are spaced apart and parallel with each other. A nut threadably engages each shaft, and these nuts are swivelly secured to the nest which permits a small amount of angular and radial deflection of the nut and shafts during movement of the nest from its lower to its upper position. An electric servo-motor is associated with each threaded shaft to rotatably drive the shafts substantially in unison with each other during the travel approach phase, and then allows in final a slight disynchronization of them, to insure an equalization of the hemming effort applied on each edge of the part, in both pre-hemming and hemming operations.

Claims13

Dependent claims

In a hemming machine of the type having a base, a nest for supporting a sheet metal part to be hemmed, at least one die, and means for moving at least one die into and out of registry with said nest, an improved actuator for vertically moving said nest relative to said base toward and away from said die comprising:

at least three elongated and externally threaded shafts, each shaft having one end rotatably mounted to said base so that said shafts are spaced apart and parallel with each other,
means mounted to said nest for threadably receiving a second end of each shaft, said threadably receiving means being fixed against rotation to said nest,
servo-motor means associated with each shaft for rotatably driving said shafts substantially in synchronism with each other,
wherein said threadably receiving means further comprises a nut which threadably engages said shaft, a first externally splined annulus coaxially disposed around said nut, said first annulus secured to the nest, a second externally splined annulus coaxially disposed around and secured to said nut so that said second annulus is axially spaced from said first annulus, an internally splined tube disposed around first and second annuli so that said internal spines on said tube intermesh with said external splines on said annuli, and
means for swivelly mounting said nut to the nest.

2 more elements

Dependencies are inferred from the claim text.