US3735823A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Impact motive implement
Assignee: Nippon Pneumatic Manufacturing Co Ltd
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Filing: 1971-04-19
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Granted: 1973-05-29
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Expires: 1991-04-19
Abstract
Abstract An impact motive implement for a fluid impact tool or the like. The implement has a main body having an upper cylinder and a lower cylinder. An upper piston and a lower piston are fitted into the two cylinders and connected with a piston rod. An impact tool is disposed under the main body against the upper end of which the lower end of the lower piston strikes when the piston are lowered. A main valve opens and closes an oil inlet port and an oil outlet port leading to the oil chamber in the lower portion within the lower cylinder, and a limiting valve is moved by the upper piston as it rises. The operating portion of the main valve and the limiting valve are correlated so that the main valve will shut off the oil chamber and the oil inlet port and connect the oil chamber and the oil outlet port by feeding compressed high pressure gas in the upper chamber within the upper cylinder to the operating portion of the main valve when the limiting valve is moved by the upper piston, and the oil chamber and the oil inlet port are connected and the oil chamber and the oil outlet are shut off when the limiting valve is not moved by the upper piston, and when the oil chamber is connected with the oil inlet port, the lower piston is pressed upward by the pressure oil fed into the oil chamber.
Inventors
- 👤 H Nara Terada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:22
CPC Classifications
B; B25; B25D; B25D9/00; B25D9/06; B25D9/12
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
306 words
An impact motive implement, comprising a main body having an upper cylinder and a lower cylinder, an upper piston and a lower piston fitted in the respective cylinders and a piston rod connecting said pistons and a lower end on said lower piston having a smaller diameter than said lower cylinder, a tool holder on the lower end of the main body and an impact tool movably mounted in said tool holder and against the upper end of which the lower end of the lower piston strikes when both pistons are lowered, said body having an oil inlet port opening into said lower cylinder at a point below said lower piston when said lower piston is in the lowermost position and said body having an oil outlet port opening out of said lower cylinder, a compressed gas operated main valve slidable in said implement between a first position in which it closes the oil outlet port and opens said oil inlet port and a second position in which it closes said oil inlet port and opens said oil outlet port, said main body having a passage therethrough from said upper cylinder to said main valve, and a limiting valve in said passage and normally closing said passage and engageable by said upper piston near the upper limit of its movement for opening said limiting valve, whereby when the main valve is in the positioN with the oil inlet port open, oil under pressure can be admitted to the lower cylinder to raise the pistons, compressing gas in the upper cylinder above the upper piston, until the upper piston opens the limiting valve, whereupon the compressed gas in the upper cylinder shifts the main valve to open the oil outlet port and the compressed gas in the upper cylinder drives the pistons downwardly against the impact tool.
Claim 2
Dependent Claim
306 words
An impact motive implement, comprising a main body having an upper cylinder and a lower cylinder, an upper piston and a lower piston fitted in the respective cylinders and a piston rod connecting said pistons and a lower end on said lower piston having a smaller diameter than said lower cylinder, a tool holder on the lower end of the main body and an impact tool movably mounted in said tool holder and against the upper end of which the lower end of the lower piston strikes when both pistons are lowered, said body having an oil inlet port opening into said lower cylinder at a point below said lower piston when said lower piston is in the lowermost position and said body having an oil outlet port opening out of said lower cylinder, a compressed gas operated main valve slidable in said implement between a first position in which it closes the oil outlet port and opens said oil inlet port and a second position in which it closes said oil inlet port and opens said oil outlet port, said main body having a passage therethrough from said upper cylinder to said main valve, and a limiting valve in said passage and normally closing said passage and engageable by said upper piston near the upper limit of its movement for opening said limiting valve, whereby when the main valve is in the positioN with the oil inlet port open, oil under pressure can be admitted to the lower cylinder to raise the pistons, compressing gas in the upper cylinder above the upper piston, until the upper piston opens the limiting valve, whereupon the compressed gas in the upper cylinder shifts the main valve to open the oil outlet port and the compressed gas in the upper cylinder drives the pistons downwardly against the impact tool.
Claim 3
Dependent Claim
135 words
An impact motive implement as claimed in claim 1 in which said main body has a middle cylinder between said upper and lower cylinders through which said piston rod extends, said main valve being a cylindrical sleeve slidable in said lower cylinder between the wall of said cylinder and said lower piston, the oil outlet port being in the bottom of said lower piston and being opened when said main valve is raised above the lowermost position thereof, and said main valve having an opening therein which in the lowermost position of the main valve is aligned with said oil inlet port, and the upper end of said main valve having a piston portion slidable in said middle cylinder, said passage through the main body opening into said middle cylinder beneath the main valve piston.
Claim 4
Dependent Claim
79 words
An impact motive implement as claimed in claim 2 wherein said main body has a further passage therethrough from a point in said upper cylinder just above said upper piston when said upper piston is in the lowermost position to the middle cylinder above the uppermost position of the main valve piston, whereby when the pistons have reached their lowermost position, gas under pressure will flow into said middle cylinder and return said main valve to the lowermost position.
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) | 1976-05-28 | 1976-11-27 | 1977-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-28 | 1980-11-27 | 1981-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-28 | 1984-11-27 | 1985-05-29 | $7700.00 | Window Closed / Lapsed |