US PATENT SUBCLASS 72 / 350
.~.~ With application of frictional restraining force to work during deformation

Current as of: June, 1999
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72 /   HD   METAL DEFORMING

343  DF  BY USE OF CLOSED-DIE AND COACTING WORK-FORCER (E.G., PUSH-DRAWING) {3}
347  DF  .~ Cup or shell drawing (i.e., deep drawing) {2}
350.~.~ With application of frictional restraining force to work during deformation {1}
351  DF  .~.~.~> With yieldable actuation of work-gripper (e.g., spring-biased blank-holder)

DEFINITION

Classification: 72/350

With application of frictional restraining force to work during deformation:

(under subclass 347) Subject matter utilizing a nonpositive

work gripper and actuating means for making said gripper effective to engage work, said actuating means or said gripper embodying adjustable or yieldable structure which is intended to be capable of so limiting or regulating the force of engagement of said gripper with the work as to permit movement (i.e., slippage) of a portion of the gripped work in response to internal stresses developed therein by and during the motion of said movable member.

(1) Note. Subclasses 350+ is loci for deep-drawing apparatus utilizing a "blank holder" or "clamp ring" which is so actuated that it permits work material to slip gradually into the bore of the draw ring or die during the drawing of a cup or shell. The slippage of work under frictional restraint distinguishes the blank holder of this subclass from the nondeforming work gripping clamp which characterizes preceding subclasses 293 (see accompanying diagram). [figure] [caption]Deep-drawing with frictional restraint on work (subclass 350).

(2) Note. The blank holder of this subclass has the effect of a metal-deforming tool or tool couple acting to modify the operation of the plunger and draw ring. Similar structure may be found in subclasses 312+, where, however, no yielding or slippage function is disclosed or desired.

SEE OR SEARCH THIS CLASS, SUBCLASS:

293+, for a positively gripping blank-holding clamp and coacting metal-deforming tool.

417, for interrelated blank holder mover and tool mover.