US3701386A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic drifter
Assignee: Dresser Industries Inc
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Filing: 1970-12-11
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Granted: 1972-10-31
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Expires: 1990-12-11
Abstract
Abstract A hydraulically-actuated percussion drill having a hydraulic control valve arranged so that hole-cleaner air can be directed through an axial passage in the piston without interference from the hydraulic valve; the piston is annular so that its central bore acts as an air passage. Oil drainage grooves are provided at the piston-housing joints where high pressure oil might otherwise tend to escape into the air passage; air pressure is used to retard leakage of oil past the grooves. Preferably the piston is built to include a cushioner flange which moves into hydraulic snubber cavities to decelerate the piston. The hydraulic supply system is such that high pressure oil is continually washed through the snubber cavities to take away heat developed by the snubbing actions.
Inventors
- 👤 Jacob E Feucht
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:01
CPC Classifications
E; E21; E21B; E21B6/00; B; B25; B25D; B25D9/00; B25D9/06; B25D9/12; Y; Y10; Y10S; Y10S173/00; Y10S173/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
88 words
A percussion drill having a housing and a striker pistondrill steel assembly disposed therein; said housing defining separate hydraulic chambers alternately pressurized, one above the other, for reciprocating the piston back and forth in the housing; said drill steel having a reduced diameter shaft portion extending through a bearing at the work output end of the housing and an enlarged impact-receiver portion loosely keyed to a surrounding drive gear within the housing, whereby the drill steel caN wobble about the bearing while being rotated by the drive gear.
Claim 2
Dependent Claim
88 words
A percussion drill having a housing and a striker pistondrill steel assembly disposed therein; said housing defining separate hydraulic chambers alternately pressurized, one above the other, for reciprocating the piston back and forth in the housing; said drill steel having a reduced diameter shaft portion extending through a bearing at the work output end of the housing and an enlarged impact-receiver portion loosely keyed to a surrounding drive gear within the housing, whereby the drill steel caN wobble about the bearing while being rotated by the drive gear.
Claim 3
Dependent Claim
50 words
The drill of claim 1 wherein the piston and drill steel are formed with communicating air passages for hole-cleaner air, and the housing is provided with an air seal at the bearing-drill steel joint such that compressed air is prevented from leaking through the work output end of the drill.
Claim 4
Dependent Claim
88 words
A percussion drill comprising a striker piston slidably confined within a drill housing; a first low area work chamber continually pressurized with hydraulic liquid for retracting the piston, and a second high area work chamber intermittently pressurized with hydraulic liquid for advancing the piston; said piston having a passage therethrough for conducting high pressure hole-cleaner air to the hole being drilled; said housing having annular hydraulic drain grooves at the piston-housing joints where hydraulic liquid could otherwise leak from the pressurized work chamber to the piston air passage.
Claim 5
Dependent Claim
88 words
A percussion drill comprising a striker piston slidably confined within a drill housing; a first low area work chamber continually pressurized with hydraulic liquid for retracting the piston, and a second high area work chamber intermittently pressurized with hydraulic liquid for advancing the piston; said piston having a passage therethrough for conducting high pressure hole-cleaner air to the hole being drilled; said housing having annular hydraulic drain grooves at the piston-housing joints where hydraulic liquid could otherwise leak from the pressurized work chamber to the piston air passage.
Claim 6
Dependent Claim
42 words
The drill of claim 3 and further comprising means for causing the air pressure to be materially higher than the hydraulic drain pressure, whereby the air pressure prevents leakage of hydraulic liquid from the associated drain groove into the piston air passage.
Claim 7
Dependent Claim
63 words
The drill of claim 3 wherein the piston air passage comprises a relatively small diameter hole-cleaner air passage extending rearwardly from the striker end of the piston, and a relatively large diameter counterbore extending forwardly from the rear end of the piston; said housing including a fixed air admission tube extending forwardly into the counterbore to deliver air to the small diameter passage.
Claim 8
Dependent Claim
36 words
The drill of claim 5 wherein the outside diameter of the piston at its striker end is larger than the diameter of the counterbore, whereby the air pressure continually exerts a rearward bias on the piston.
Claim 9
Dependent Claim
121 words
A percussion drill comprising a striker piston slidably confined within a drill housing; a first low area work chamber continually pressurized with hydraulic liquid for moving the piston in one direction, and a second high area work chamber intermittently pressurized with hydraulic liquid for moving the piston in the other direction; said piston having an enlarged cushioner flange arranged within the first continually pressurized chamber; said first chamber comprising a central chamber space materially larger in diameter than the cushioner flange, and reduced diameter end cavity spaces only slightly larger in diameter than the cushioner flange, whereby the piston can move freely while the flange is in the central chamber space but less freely when the flange enters either end cavity.
Claim 10
Dependent Claim
121 words
A percussion drill comprising a striker piston slidably confined within a drill housing; a first low area work chamber continually pressurized with hydraulic liquid for moving the piston in one direction, and a second high area work chamber intermittently pressurized with hydraulic liquid for moving the piston in the other direction; said piston having an enlarged cushioner flange arranged within the first continually pressurized chamber; said first chamber comprising a central chamber space materially larger in diameter than the cushioner flange, and reduced diameter end cavity spaces only slightly larger in diameter than the cushioner flange, whereby the piston can move freely while the flange is in the central chamber space but less freely when the flange enters either end cavity.
Claim 11
Dependent Claim
31 words
The drill of claim 7 wherein the entire hydraulic supply is initially admitted to the low area work chamber, thereafter to the high area work chamber, and finally to the drain.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-31 | 1976-05-01 | 1976-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-31 | 1980-05-01 | 1980-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-31 | 1984-05-01 | 1984-10-31 | $7700.00 | Window Closed / Lapsed |