Metal deforming – By use of non-deforming work-gripping clamp and relatively... – With interrelated clamp closer and tool mover
Patent
1996-10-07
1998-05-05
Crane, Daniel C.
Metal deforming
By use of non-deforming work-gripping clamp and relatively...
With interrelated clamp closer and tool mover
72312, 2924358, B21D 3902
Patent
active
057460833
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/GB95/00288, filed Feb. 13, 1995.
FIELD OF INVENTION
This invention relates to hemming machines for hemming the peripheral edge of sheet metal fabrication such as vehicle door panels.
BACKGROUND OF THE INVENTION
Metal hemming machines for hemming the external periphery of sheet metal fabrications such as vehicle doors are supplied inter alia by Western Atlas Inc of Warren, Mich. 48091, USA. Such machines provide an anvil on which the metal fabrication can rest and a pair of tools or steels which first of all bend over an upturned lip along the periphery which is to be hemmed and then flatten the bent over lip against the fabrication either so as to simply reinforce the edge or trap therein an edge of a second part of the fabrication.
It is an object of the present invention to adapt such a machine to allow an internal opening within a sheet metal fabrication likewise to be hemmed at the same time as the fabrication is externally hemmed without removing the fabrication from the machine and preferably without moving the fabrication within the machine.
SUMMARY OF THE INVENTION
According to the present invention in a hemming machine adapted to hem a sheet metal fabrication around an external peripheral edge thereof and comprising an anvil on which the fabrication rests which itself is apertured so as to register at least with an aperture in the metal fabrication which is also to be internally hemmed, additional hemming apparatus mounted at the upper end of drive and support means located below and protruding up through the opening in the anvil so as to protrude through the opening in the fabrication, comprising:
1. a hemming tool which is displaceable upwardly and downwardly as well as horizontally and which includes a chamfered lower leading edge,
2. a block carrying the tool at one end and movable in a slide, the drive means acting to position the slide vertically,
3. drive means for positioning the block within the slide to position the tool horizontally,
4. a second anvil resiliently displaceable and engaging the underside of the tool normally to raise the latter relative to its lowermost position to enable the tool to move horizontally and effect preliminary internal hemming, and
5. the upper surface of the block is adapted thereafter to withstand an impact force and transmit same to the tool to force the tool in a downward direction until the tool and block bottom on stop means.
Preferably the horizontal movement of the block and tool is achieved by a vertical movement of a nut on a lead screw itself driven by a servo motor and the vertical movement is translated to horizontal movement by means of cam means acting on the block.
In one embodiment, the lead screw nut includes an upstanding arm which over part of its length is bent over at an angle to the vertical so that movement of the arm in a vertical sense causes a member engaging the inclined part of the arm to be moved backwards and forwards.
Alternatively the block may be driven back and forward by hydraulic means or other drive means such as a servo motor located in line with the block and slide.
According to a particularly preferred feature of the invention, the impact force may be applied to the block by means of a hammer member attached to the drive mechanism associated with the external hemming tooling and synchronisation is provided between the internal and external hemming tooling operations so that the hammer attached to the external tooling is ready to descend onto the block of the internal tooling at the same instant as the internal tooling has achieved its required lateral displacement so that the flat underside of the inner tool is overlying the flattened tab of the internal hem so that the final squeeze of both internal and external hem is achieved by the same tool acting directly on the external hem and indirectly through the block and hemming tool of the internal hemming arrangement.
Where the whole of the external periphery of the fabrication is to be externally hemmed, hemming tooling will be
REFERENCES:
patent: 3147726 (1964-09-01), Tribe
patent: 3191414 (1965-06-01), Kollar
patent: 3566817 (1971-03-01), DeCastelet
patent: 3598073 (1971-08-01), St. Denis
patent: 5086638 (1992-02-01), David
patent: 5259230 (1993-11-01), Beyers
Kovarovic Josef
Kowalewsky John Ralph
Crane Daniel C.
Western Atlas U.K. Limited
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