US3875784A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential pressure device for folding apparatus
Assignee: US Amada Ltd
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Filing: 1974-03-04
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Granted: 1975-04-08
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Expires: 1994-03-04
Abstract
Abstract A folding apparatus is provided with a pivotal folding punch that moves past a work sheet supporting surface and an anvil. Hydraulically powered piston and cylinder mechanisms pull the anvil against the work sheet supporting surface while simultaneously pulling the punch about the anvil. Second hydraulic cylinder and piston mechanisms provide a variable resistance force against the movement of the punch.
Inventors
- 👤 Dennis Daniels
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:10
CPC Classifications
B; B21; B21D; B21D5/00; B21D5/04; B21D5/042
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
164 words
A variable load applying apparatus for a fluid-operated folding machine of the type having a frame provided with a work sheet supporting surface, an anvil spaced from said work sheet supporting surface, to allow free movement of a work sheet beneath and having a folding edge, a punch mounted for pivotal movement past said work sheet supporting surface and folding edge to bend a work sheet clamped between the anvil and work sheet supporting surface, first powered means for moving the anvil toward said work sheet supporting surface for clamping a work sheet therebetween and for moving said punch to bend the work sheet, and wherein the clamping force is varied directly with the punch bending force, the improvement comprising: means for providing a variable resistance force against movement of said punch so that initial movement of said first powered means effects a variable clamping force on the work sheet dependent on said resistance force, and variable control means for determining the resistance force.
Claim 2
Dependent Claim
164 words
A variable load applying apparatus for a fluid-operated folding machine of the type having a frame provided with a work sheet supporting surface, an anvil spaced from said work sheet supporting surface, to allow free movement of a work sheet beneath and having a folding edge, a punch mounted for pivotal movement past said work sheet supporting surface and folding edge to bend a work sheet clamped between the anvil and work sheet supporting surface, first powered means for moving the anvil toward said work sheet supporting surface for clamping a work sheet therebetween and for moving said punch to bend the work sheet, and wherein the clamping force is varied directly with the punch bending force, the improvement comprising: means for providing a variable resistance force against movement of said punch so that initial movement of said first powered means effects a variable clamping force on the work sheet dependent on said resistance force, and variable control means for determining the resistance force.
Claim 3
Dependent Claim
22 words
The apparatus of claim 1, said means for providing a variable resistance force including second powered means flexibly coupled to said punch.
Claim 4
Dependent Claim
60 words
The apparatus of claim 1, said first powered means including flexible coupling means secured to opposite ends of said punch, said second powered means including second flexible coupling means secured to opposite ends of said punch, said first and second powered means including hydraulic means for providing simultaneously opposed forces on said punch for controlling pivotal movement of the punch.
Claim 5
Dependent Claim
71 words
The apparatus of claim 3, said folding machine including transversely spaced, upright side frames having guide slots therein, said first powered means including cylinders and piston rods, linkage means pivotally securing each cylinder to said anvil, said flexible coupling means secured between the piston rods and said punch whereby retraction of said piston rods pulls said cylinders against said linkage means to push said anvil against said work piece supporting surface.
Claim 6
Dependent Claim
81 words
The apparatus of claim 2, said cylinders and piston rods coupled between the punch and said frame, said second powered means including force resistance means for providing a variable resistance force including hydraulic flow lines coupled to said cylinders, said control means including a pressure relief valve coupled to said hydraulic flow lines for relieving fluid pressure in said cylinders to extend the piston rods and thus allow movement of the punch, only after the resistance force exceeds a predetermined amount.
Claim 7
Dependent Claim
54 words
The apparatus of claim 5, said first powered means including primary cylinders and piston rods and hydraulic lines to said cylinders, said control means including main control valve means for directing flow to said primary cylinders to begin moving the anvil against the work sheet and thence pivoting the punch at a controlled rate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |