Patent US3921731A successfully refreshed from Google Patents.
US3921731A
Expired / Lapsed
US
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Hydraulic impact device
Assignee: Atlas Copco AB
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Filing: 1974-07-23
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Granted: 1975-11-25
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Expires: 1994-07-23
Abstract
Abstract An hydraulically powered impact device intended for rock drilling having a hydraulic fluid section for reciprocately powering an impact piston and a non-hydraulic section into which the impact piston as well as a drill stem adapter extend. The non-hydraulic section, which contains a flush medium supply chamber and a rotation transmitting chuck bushing, is connected to a pressure air source for establishing two separate pressure air barriers, the objects of which are to seal off, lubricate and cool the non-hydraulic section.
Inventors
- 👤 Carl Gosta Bernhard Ekwall
- 👤 Sven Ingemar Johansson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:43
CPC Classifications
E; E21; E21B; E21B6/00; B; B25; B25D; B25D17/00; B25D17/08; B25D17/084; B25D17/26; B25D17/265; Y; Y10; Y10S; Y10S173/00; Y10S173/03
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
139 words
A hydraulic impact device intended for rock drilling, comprising: a housing and an impact piston, said housing being divided into a hydraulic fluid section in which the impact piston is reciprocately powered, and a non-hydraulic section into which the forward end of the impact piston extends; a tool aperture provided in the non-hydraulic section for receiving the rear end of a drill stem or drill stem adapter; a flush medium supply chamber provided in the non-hydraulic section in communication with the tool aperture; and pressure air supply means provided in the non-hydraulic section of the housing and including means for coupling pressure air in front of and behind the flush medium supply chamber establishing two pressure air barriers in the non-hydraulic section, one in front of and one behind the flush medium supply chamber relative to the impact direction.
Claim 2
Dependent Claim
139 words
A hydraulic impact device intended for rock drilling, comprising: a housing and an impact piston, said housing being divided into a hydraulic fluid section in which the impact piston is reciprocately powered, and a non-hydraulic section into which the forward end of the impact piston extends; a tool aperture provided in the non-hydraulic section for receiving the rear end of a drill stem or drill stem adapter; a flush medium supply chamber provided in the non-hydraulic section in communication with the tool aperture; and pressure air supply means provided in the non-hydraulic section of the housing and including means for coupling pressure air in front of and behind the flush medium supply chamber establishing two pressure air barriers in the non-hydraulic section, one in front of and one behind the flush medium supply chamber relative to the impact direction.
Claim 3
Dependent Claim
31 words
Impact device according to claim 1 comprising a metering device coupling a pressure air source to said pressure air supply means, said metering device supplying lubricating oil to the pressure air.
Claim 4
Dependent Claim
50 words
Impact device according to claim 1 wherein said pressure air supply means comprises passage means in said non-hydraulic section of said housing, said passage means including a first passage extending in front of the flush medium supply chamber and at least one passage extending behind the flush medium supply chamber.
Claim 5
Dependent Claim
112 words
Impact device according to claim 1 comprising a rotation transmitting chuck bushing mounted in said non-hydraulic section for cooperation with the rear end of a drill stem or drill stem adapter, the chuck bushing being located between the flush medium supply chamber and the hydraulic fluid section; and said pressure air supply means includes at least one pressure air inlet opening in the housing behind the chuck bushing and an air outlet opening in the housing in front of the chuck bushing, relating to the impact direction, the chuck bushing permitting an air flow therethrough, whereby the rear pressure air barrier is comprised of an air flow extending through said chuck bushing.
Claim 6
Dependent Claim
31 words
Impact device according to claim 4 comprising a metering device coupling a pressure air source to said pressure air supply means, said metering device supplying lubricating oil to the pressure air.
Claim 7
Dependent Claim
49 words
Impact device according to claim 1, comprising an annular space communicating with the tool aperture and wherein said pressure air supply means includes means for supplying pressure air to said annular space, the forward pressure air barrier being comprised of an air flow extending out through said annular space.
Claim 8
Dependent Claim
112 words
Impact device according to claim 6 comprising a rotation transmitting chuck bushing mounted in said non-hydraulic section for cooperation with the rear end of a drill stem or drill stem adapter, the chuck bushing being located between the flush medium supply chamber and the hydraulic fluid section; and said pressure air supply means includes at least one pressure air inlet opening in the housing behind the chuck bushing and an air outlet opening in the housing in front of the chuck bushing, relating to the impact direction, the chuck bushing permitting an air flow therethrough, whereby the rear pressure air barrier is comprised of an air flow extending through said chuck bushing.
Claim 9
Dependent Claim
31 words
Impact device according to claim 6 comprising a metering device coupling a pressure air source to said pressure air supply means, said metering device supplying lubricating oil to the pressure air.
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) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |