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Patent US3695366A successfully refreshed from Google Patents.
US3695366A
Expired / Lapsed
US
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Hydraulic hammer with back pressure isolation
Assignee: Dresser Rand Co
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Filing: 1970-11-09
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Granted: 1972-10-03
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Expires: 1990-11-09
Abstract
Abstract An improved hydraulic hammer constructed to eliminate frequency variations in operation due to fluctuating back pressure. A flow path from a hammer operating piston to a fluid outlet is provided with a venturi to isolate the piston from fluctuation in back pressure downstream of the restriction.
Inventors
- 👤 Ernst F Klessig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:38
CPC Classifications
B; B25; B25D; B25D9/00; B25D9/06; B25D9/12; Y; Y10; Y10S; Y10S173/00; Y10S173/04
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
159 words
A hydraulic hammer comprising: a. a casing having a bore; b. a hammer received within said bore for reciprocating movement therein; c. a work performing member operatively associated with said casing to be struck by said hammer during reciprocation of said hammer; d. means for reciprocating said hammer within said bore including 1. means within said bore having opposed first and second pressure surfaces, said first surface being of greater size than said second surface, 2. first means establishing constant fluid communication between said second surface and a source of hydraulic fluid under pressure, and 3. second means alternately establishing fluid communication between said first surface and said source or a hydraulic fluid outlet; and e. means associated with one of said second means and said fluid outlet defining a venturi to maintain back pressure against said first surface at a relatively constant level when said second means establishes fluid communication between said first surface and said fluid outlet.
Claim 2
Dependent Claim
159 words
A hydraulic hammer comprising: a. a casing having a bore; b. a hammer received within said bore for reciprocating movement therein; c. a work performing member operatively associated with said casing to be struck by said hammer during reciprocation of said hammer; d. means for reciprocating said hammer within said bore including 1. means within said bore having opposed first and second pressure surfaces, said first surface being of greater size than said second surface, 2. first means establishing constant fluid communication between said second surface and a source of hydraulic fluid under pressure, and 3. second means alternately establishing fluid communication between said first surface and said source or a hydraulic fluid outlet; and e. means associated with one of said second means and said fluid outlet defining a venturi to maintain back pressure against said first surface at a relatively constant level when said second means establishes fluid communication between said first surface and said fluid outlet.
Claim 3
Dependent Claim
19 words
first means establishing constant fluid communication between said second surface and a source of hydraulic fluid under pressure, and
Claim 4
Dependent Claim
19 words
first means establishing constant fluid communication between said second surface and a source of hydraulic fluid under pressure, and
Claim 5
Dependent Claim
22 words
The hydraulic hammer of claim 1 wherein said second means comprises a control valve and said venturi defining means is carried thereon.
Claim 6
Dependent Claim
27 words
means, including a surface to be subjected to hydraulic fluid under pressure, for driving said hammer within said bore in a direction opposite said one direction, and
Claim 7
Dependent Claim
27 words
means, including a surface to be subjected to hydraulic fluid under pressure, for driving said hammer within said bore in a direction opposite said one direction, and
Claim 8
Dependent Claim
92 words
means for alternately establishing a first fluid flow path between said sUrface and a source of hydraulic fluid under pressure and a second flow path between said surface and a hydraulic fluid outlet; and e. means defining a venturi in said second flow path for isolating pressure fluctuations downstream of the isolating means from fluid in said second flow path and upstream of the isolating means whereby pressure against said surface is maintained constant when said second flow path is established to eliminate variations of operational frequency due to said pressure fluctuations.
Claim 9
Dependent Claim
92 words
means for alternately establishing a first fluid flow path between said sUrface and a source of hydraulic fluid under pressure and a second flow path between said surface and a hydraulic fluid outlet; and e. means defining a venturi in said second flow path for isolating pressure fluctuations downstream of the isolating means from fluid in said second flow path and upstream of the isolating means whereby pressure against said surface is maintained constant when said second flow path is established to eliminate variations of operational frequency due to said pressure fluctuations.
Claim 10
Dependent Claim
53 words
The hydraulic hammer of claim 1 wherein said second means comprises a bore and a reciprocably movable valve spool having a reduced diameter portion received in the bore, and said venturi defining means comprises a land on said spool reduced diameter portion and having a diameter less than the diameter of said bore.
Claim 11
Dependent Claim
63 words
second means alternately establishing fluid communication between said first surface and said source or a hydraulic fluid outlet; and e. means associated with one of said second means and said fluid outlet defining a venturi to maintain back pressure against said first surface at a relatively constant level when said second means establishes fluid communication between said first surface and said fluid outlet.
Claim 12
Dependent Claim
63 words
second means alternately establishing fluid communication between said first surface and said source or a hydraulic fluid outlet; and e. means associated with one of said second means and said fluid outlet defining a venturi to maintain back pressure against said first surface at a relatively constant level when said second means establishes fluid communication between said first surface and said fluid outlet.
Claim 13
Dependent Claim
52 words
A hydraulic hammer comprising: a. a casing having a bore; b. a hammer received within said bore for reciprocating movement therein; c. a work performing member operatively associated with said casing to be struck by said hammer during reciprocation of said hammer; d. means for reciprocating said hammer within said bore including
Claim 14
Dependent Claim
52 words
A hydraulic hammer comprising: a. a casing having a bore; b. a hammer received within said bore for reciprocating movement therein; c. a work performing member operatively associated with said casing to be struck by said hammer during reciprocation of said hammer; d. means for reciprocating said hammer within said bore including
Claim 15
Dependent Claim
119 words
A hydraulic hammer according to claim 4 wherein said hammer is arranged to be driven against said member when said first surface is in fluid communication with said source; said second means includes a second bore in fluid communication with the end of the bore in the casing adjacent said first surface and with said fluid outlet, and a valve spool having a reduced diameter portion received within said second bore for reciprocal movement therein to interconnect said fluid outlet and said casing bore end in one position of movement within said second bore; and said venturi defining means comprises an annular projection on said reduced diameter portion having a lesser diameter than the diameter of said second bore.
Claim 16
Dependent Claim
36 words
A hydraulic hammer according to claim 5 wherein the sides of said projection are tapered with the side of said projection adjacent said outlet having a greater longitudinal extent than the opposite side of said land.
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) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |