US3785444A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Jackhammer
Assignee: Individual
•
Filing: 1972-10-10
•
Granted: 1974-01-15
•
Expires: 1992-10-10
Abstract
Abstract A jackhammer has a frame which supports a trip wheel and a power device for rotating the wheel. A striker bar is held by the frame against the periphery of the wheel. The striker bar has a notch in it and the wheel has peripheral trip fingers to engage the notch alternately to raise and release the striker bar. Coiled springs in the frame are operatively connected to the striker bar to be compressed when the bar is lifted and drive the bar downward when it is released. A drill stem is guided in the frame for limited vertical movement with respect to the frame. A head on the striker bar has a sleeve that strikes a shoulder on the drill stem to deliver the impact caused by the springs when the striker bar is released. When desired, a pawl and ratchet mechanism is included to use the upward movement of the striker bar to turn the drill stem.
Inventors
- 👤 P Gray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:07
CPC Classifications
E; E21; E21B; E21B6/00; E21B21/00; E21B21/01; Y; Y10; Y10T; Y10T279/00; Y10T279/17; Y10T279/17111
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
167 words
In a jackhammer, a frame having means therein to support and guide a drill stem; a trip wheel on the frame having trip fingers thereon; a power device on the frame for rotating the trip wheel; a striker bar guided in the frame for endwise movement tangentially of the wheel and having a crosshead thereon; a notch in the striker bar operable to receive the trip fingers for lifting the bar; coiled springs carried by the frame and under compression between the top of the frame and the crosshead; a head on the striker bar at its lower end; a drill stem mounted for limited endwise movement in the frame and having a shoulder thereon positioned to receive an impact from the head when the springs force the striker bar down upon release of the bar by the trip fingers; the head including a sleeve into which the drill stem extends; and the frame having a sleeve fixed therein in which the sleeve of the head reciprocates.
Claim 2
Dependent Claim
167 words
In a jackhammer, a frame having means therein to support and guide a drill stem; a trip wheel on the frame having trip fingers thereon; a power device on the frame for rotating the trip wheel; a striker bar guided in the frame for endwise movement tangentially of the wheel and having a crosshead thereon; a notch in the striker bar operable to receive the trip fingers for lifting the bar; coiled springs carried by the frame and under compression between the top of the frame and the crosshead; a head on the striker bar at its lower end; a drill stem mounted for limited endwise movement in the frame and having a shoulder thereon positioned to receive an impact from the head when the springs force the striker bar down upon release of the bar by the trip fingers; the head including a sleeve into which the drill stem extends; and the frame having a sleeve fixed therein in which the sleeve of the head reciprocates.
Claim 3
Dependent Claim
49 words
The jackhammer defined in claim 1 with; a turn shaft alongside the striker bar in the frame operably connected to the striker bar to turn as the striker bar moves up and down; and means connecting the turn shaft to the drill stem operable to rotate the drill stem.
Claim 4
Dependent Claim
46 words
The jackhammer defined in claim 1 wherein the drill stem is tubular and open at the top into the sleeve of the head; and a fluid supply conduit is connected to the head to supply fluid through the sleeve of the head into the drill stem.
Claim 5
Dependent Claim
24 words
The jackhammer defined in claim 1 wherein the frame has removable guide means spaced below the striker bar head and surrounding the drill stem.
Claim 6
Dependent Claim
31 words
The jackhammer defined in claim 1 embodying a spring pressed roller bearing on the side of the striker bar opposite the place of contact between the striker bar and the wheel.
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) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |