Apparatus for straight line shearing
AssigneeEmhart Industries, Inc.
InventorFrancis A. Dahms
Life of this patent
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Abstract
A straight line shearing mechanism which includes a unique pneumatic control system to cause the operation of the shears. One feature involves the cushioning of the piston member of the pneumatic cylinder assembly on the return stroke. Another feature is the provision of an automatic retract to open the shears in the event that the shear blades do not complete their cutting stroke. Also, one blade of a set of shear blades may tilt in the event of excess tension between the blades. Additionally, one shear blade is pivotally adjustable about a pin member having an axis extending in the direction of travel of the blades. Further, the drop guides are horizontally adjustable relative to its associated shear blade in the direction of travel of the shear blade and also adjustable about a vertical axis.
Claims12
An apparatus for use with a feeder for shearing gobs from a column of plastic material comprising:
- (a) at least one set of oppositely disposed shear blades movable in a straight line toward and away from each other between open and shearing positions;
- and
- (b) a pneumatic control system for operating said shear blades, said control system including:
- (i) a source of fluid pressure;
- (ii) pneumatic cylinder assembly means including a piston member and operating rod for driving said shear blades between said open and shearing positions;
- (iii) means connecting said pneumatic cylinder assembly means to said source of fluid pressure including a first valve having first and second positions, said first position permitting fluid pressure to flow to one side of said piston to move said piston into the shearing position, said second position permitting fluid pressure flow to the other side of said piston member to move said piston member into the open position;
- (iv) means connecting said source of fluid pressure to said first valve to cause the actuation thereof including a second valve having first and second positions, said first position permitting fluid pressure to flow to said first valve to actuate said first valve into its first position, said second position permitting fluid pressure flow to said first valve to actuate said first valve into its second position;
- (v) means connecting said source of fluid pressure to said second valve to cause the actuation thereof into its first position and including a third valve having a normal position blocking fluid pressure flow and an actuated position permitting fluid pressure flow;
- and
- (vi) means driven by said operating rod to actuate said second valve into its second position after said shear blades have moved to their shearing position.
Dependencies are inferred from the claim text.