US3685593A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid operated rock drill having an independent rotation motor
Assignee: Chicago Pneumatic Tool Co LLC
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Filing: 1970-11-03
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Granted: 1972-08-22
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Expires: 1990-11-03
Abstract
Abstract A rock drill having a pneumatically reciprocable piston hammer to pound a striking bar. Live air is caused to be applied continuously to one end of the hammer and alternately to the opposite end. A fluid motor is operable to reciprocate a drive piston relative to live air feed ports and to the hammer to cause development of differential pneumatic pressures alternately at opposite ends of the hammer to reciprocate the latter. Porting of live air to opposite ends of the hammer is arranged so that when the striking bar is withdrawn from or breaks through the work, the hammer will automatically stall even though the drive piston continues to reciprocate. Except during moments of impact of the hammer with the striking bar, pressure air is caused to continuously blow through a hole in the bar to clear away debris at the work end of the tool. A second fluid motor operates independently of the rock drill motor to transmit rotation through a gear train coupling to the striking bar as the latter is being pounded by the hammer. The coupling absorbs undesirable shocks arising between the striking bar and the second motor.
Inventors
- 👤 Lester A Amtsberg
- 👤 Paul J Bilodeau
- 👤 Sebastian F Judd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:50
CPC Classifications
B; B25; B25D; B25D9/00; B25D9/14; B25D9/26; B25D9/265; E; E21; E21B; E21B6/00; Y; Y10; Y10S; Y10S173/00; Y10S173/03
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
228 words
A rock drill including a casing having a piston chamber provided with a shoulder at its lower end, a floating piston hammer reciprocable in the chamber relative to the shoulder, the hammer being of cup-form provided with an axially projecting stem, a work steel having a retracted position in the casing wherein its top end is subject to being pounded by the stem as the hammer reciprocates and wherein the hammer is disabled by the work steel from engaging the shoulder, a pressure air inlet having passages for feeding pressure air to opposite ends of the piston hammer, and cup-form means reciprocable in and out of the cup of the hammer for developing pneumatic pressure differentials of such air alternately at opposite ends of the hammer to reciprocate it during the time the work steel is in its retracted position, wherein the work steel has a surface gear intermediately of its ends, a rotary motor operating independently of the reciprocating hammer has an output shaft, and gear train means drivingly couples the output shaft of the motor with the gear of the work steel; characterized in that the gear train means includes a worm gear shaft carrying a worm gear having a driving connection with the gear of the striking bar, and a torsion bar drivingly connecting the output shaft of the motor with the worm gear shaft.
Claim 2
Dependent Claim
228 words
A rock drill including a casing having a piston chamber provided with a shoulder at its lower end, a floating piston hammer reciprocable in the chamber relative to the shoulder, the hammer being of cup-form provided with an axially projecting stem, a work steel having a retracted position in the casing wherein its top end is subject to being pounded by the stem as the hammer reciprocates and wherein the hammer is disabled by the work steel from engaging the shoulder, a pressure air inlet having passages for feeding pressure air to opposite ends of the piston hammer, and cup-form means reciprocable in and out of the cup of the hammer for developing pneumatic pressure differentials of such air alternately at opposite ends of the hammer to reciprocate it during the time the work steel is in its retracted position, wherein the work steel has a surface gear intermediately of its ends, a rotary motor operating independently of the reciprocating hammer has an output shaft, and gear train means drivingly couples the output shaft of the motor with the gear of the work steel; characterized in that the gear train means includes a worm gear shaft carrying a worm gear having a driving connection with the gear of the striking bar, and a torsion bar drivingly connecting the output shaft of the motor with the worm gear shaft.
Claim 3
Dependent Claim
71 words
In a rock drill as in claim 1, wherein the work steel has a foremost position in which it is out of pounding range of the stem and in which the hammer is engageable with the shoulder, and means is provided which is responsive to engagement of the hammer with the shoulder to disable the cup-form means from causing development of said differential pressures alternately at opposite ends of the hammer.
Claim 4
Dependent Claim
139 words
In a rock drill including a work engaging striking bar having a surface gear intermediately of its ends, a piston hammer reciprocable to pound the bar against the work, and means for alternately pressurizing opposite ends of the hammer to reciprocate the latter, a rotary motor operating independently of the reciprocating hammer having a rotor shaft, and gear train means drivingly coupling the rotor shaft with the gear of the striking bar having the capacity for absorbing axially and rotationally directed thrusts developing in the gear train means between the motor and the striking bar, wherein the gear train means includes a worm gear shaft, a worm gear carried by the worm gear shaft having a driving connection with the gear of the striking bar, and a torsion bar drivingly connecting the rotor shaft with the worm gear shaft.
Claim 5
Dependent Claim
139 words
In a rock drill including a work engaging striking bar having a surface gear intermediately of its ends, a piston hammer reciprocable to pound the bar against the work, and means for alternately pressurizing opposite ends of the hammer to reciprocate the latter, a rotary motor operating independently of the reciprocating hammer having a rotor shaft, and gear train means drivingly coupling the rotor shaft with the gear of the striking bar having the capacity for absorbing axially and rotationally directed thrusts developing in the gear train means between the motor and the striking bar, wherein the gear train means includes a worm gear shaft, a worm gear carried by the worm gear shaft having a driving connection with the gear of the striking bar, and a torsion bar drivingly connecting the rotor shaft with the worm gear shaft.
Claim 6
Dependent Claim
60 words
In a rock drill as in claim 3, wherein the rotor and worm gear shafts are hollow and arranged in axial alignment, the torsion bar is disposed within the interior of both shafts and has a splined driven connection at one end with the rotor shaft and a splined driving connection at its opposite end with the worm gear shaft.
Claim 7
Dependent Claim
114 words
In a rock drill as in claim 4, wherein the rotor and worm gear shafts are respectively supported in a first and second pair of bearings, the motor is pneumatically operated by air carrying an oil lubricant, and passage means is provided for directing exhaust air from the motor thrOugh the first pair of the bearings to one end area of the worm gear, and other passage means is provided for directing exhaust air from the motor through a second pair of the bearings to the opposite end area of the worm gear, the torsion bar having an axially extending hole therethrough defining a connecting passage between the bearings of the said second pair.
Claim 8
Dependent Claim
62 words
In a rock drill as in claim 3, wherein the worm gear shaft has a driving spline connection with the worm gear allowing relative axial movement of the worm gear, and shock absorbing means is mounted upon the worm gear shaft in abutting relation to opposite ends of the worm gear adapted to absorb axially directed thrusts imparted to the worm gear.
Claim 9
Dependent Claim
66 words
In a rock drill as in claim 3, wherein the worm gear shaft has a driving spline connection with the worm gear allowing relative axial movement of the worm gear, the worm gear shaft is supported at each end in a separate bearing having a fixed position, and a separate shock absorbing unit is disposed between each bearing and a corresponding end of the worm gear.
Claim 10
Dependent Claim
61 words
In a rock drill as in claim 7, wherein each shock absorbing unit is slidably received upon the worm gear shaft and comprises an inner thrust ring presenting a bearing surface to an end of the worm gear, an outer thrust ring presenting a bearing surface to the related bearing, and an elastomer ring between the inner and outer thrust rings.
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) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |