CA1184449A - Pneumatic motor for rock drills and the like - Google Patents
Pneumatic motor for rock drills and the likeInfo
- Publication number
- CA1184449A CA1184449A CA000448389A CA448389A CA1184449A CA 1184449 A CA1184449 A CA 1184449A CA 000448389 A CA000448389 A CA 000448389A CA 448389 A CA448389 A CA 448389A CA 1184449 A CA1184449 A CA 1184449A
- Authority
- CA
- Canada
- Prior art keywords
- striking bar
- pneumatic
- oil
- air
- pneumatic motor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Earth Drilling (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A pneumatic motor for rock drills and the like having a reciprocating piston with valves at its opposite ends for valving motive air to the piston head from both ends of the cylinder. Large receivers are provided near the respective valves to accommodate availability of air on demand from the valves and to dampen pressure fluctuations. One of the receivers is connected to an external source of fluid under pressure; while the two receivers are interconnected by tubing external to the pneumatic motor itself. This permits the cylinder for the piston to comprise a simple tube provided with exhaust ports only. Additionally, exhaust air and oil from an air motor, which rotates the rock drill, are directed into the area between the lower end of the reciprocating piston and a striking bar for the drill rod to lubricate the .
reciprocating parts.
A pneumatic motor for rock drills and the like having a reciprocating piston with valves at its opposite ends for valving motive air to the piston head from both ends of the cylinder. Large receivers are provided near the respective valves to accommodate availability of air on demand from the valves and to dampen pressure fluctuations. One of the receivers is connected to an external source of fluid under pressure; while the two receivers are interconnected by tubing external to the pneumatic motor itself. This permits the cylinder for the piston to comprise a simple tube provided with exhaust ports only. Additionally, exhaust air and oil from an air motor, which rotates the rock drill, are directed into the area between the lower end of the reciprocating piston and a striking bar for the drill rod to lubricate the .
reciprocating parts.
Description
This invention relates to a pneumatic motor and more particularly to a motor for use in rock drills and the like.
This i.s a division of copending Canadian Patent application serial number 367,475, filed December 23, 1980.
In the past, pneumatic motors for rock ~rills and the like have been provided wherein the hammer piston includes reduced-diameter portions extending axially on opposite sides of an enlarged central piston portion. The reduce~-diameter portions include reduced area sections which act as inlet valve means for valving motive air to the piston head from both ends of the cylinder. On example of such a pneumatic motor can be found by reference to U~S. Patent No. 1,264,217, issued April 30, 1918.
The present invention resides in a pneumatic rock drill assembly of the type in which a drill rod is carried by a striking bar which is repeatedly struck by a reciprocating piston and wherein the striking bar is carried for reciprocation by a rotatable bushing connected through a gear train enclosed within a gearbox to a pneumatic motor. Passageway means is provided in the rock drill assembly for directing exhaust air and oil from the pneumatic motor to the periphery of the striking bar only to lubricate the same.
The above and othe.r features of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings which form form a part of this specification, and in which:
~
sb/~G' Figure 1 is a vertical cross-sectional view of the pneumatic motor, rock drill assembly of the inventio,n;
Fig. 2 is a top view of the apparatus shown in Fig. l; and Fig. 3 is a cross-sectional view taken along line III-III of Fig. 2 showing one of two tubes which interconnect receivers at opposite ends of the reciprocating piston assembly.
With reference now to the drawings, and particularly to Figs. 1 and 2, there is shown a rock drill assembly comprising an upper housing 10, a lower housing 12 and an intermediate hammer piston and cylinder assembly, generally indicated by the reference nlImeral 14. The upper housing 10 includes a cup-shaped member 16 into which i5 fitted a generally circular bushing part 18 to provide a first or upper receiver chamber 20 adapted for connection to a source of external aix pressure via an inlet port 22. Carried on the sb/j~
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lower housing 12 is a second generally circular bushing part 24; and between the parts 18 and 24 is a cylinder section 26 comprising a simple -tube having exhaust ports 28 formed -therein.
Reciprocable within -the cylinder 26 is the large diameter por-tion 30 of a hammer pis-ton, generally indicated by the reference numeral 32. Extending axially on opposite sides of the enlarged-diameter piston portion 30 are reduced-diameter piston portions 34 and 36. Piston portion 34 reciprocates wi-thin a sleeve or liner 38 inserted into a bore in the part 18. Simi~larly, pis-ton portion 36 recipro-cates within a sleeve or liner 40 inser-ted into a bore in the part 24. Also formed in the par-t 24 and surrounding the liner 40 is a second receiver chamber 42.
As best shown in Pi~s. 2 and 3, the housing portion 16 is formed with a si.de extension 44 having a lower flange 46 which rests on the periphery of part 18. Formed in the flan~e 46 are two openings 48 which receive -thin-walled tubes 50, one of which is shown in Fig. 3~ The other ends of the thin-walled tubes 50 are connec-ted to an elbow 52 which connects the lower ends of the -tubes wi-th ports 54 extending through the pa.rt 24 and communicating with the lower receiver chamber 42. Thus, the tubes 50. interconnec-t the upper and lower receiver chambers 20 and 42 without the necessity for machinin~ passageways i~n -the cylinder assembly. At -the same time, the tubing permits the cylinder 26 for the large diameter piston 30 -to comprise a simple tube having only the exhaust por-ts 28 formed therein.
The upper liner 38 in part 18 is provided with mab/ ~
ports 56 which con~unicate wi.-th an ~nnular passageway 58 formed in -the part 18. The passageway 58, in turn, i5 connected through por-t 60 to the recei~er chamber 20.
Similarly, the lower receiver chamber 42 is aclapted to be connec-ted -to the interior of -the cylinder formed by the liner 40 -through ports 62~ I-t will be noted that the reduced-diameter pis-ton portions 34 and 36 have necked down areas or portions 64 and 66. ~hese cooperate with -the por-ts 56 and 62 to alternately valve motive air to the upper and lower sur-~aces of the large diame-ter pi~ston portion 30. That is, with the hammer piston 32 in the position shown in F~g. 1, the lower cide o~ the la.rge didmeter pis-ton portior 30 is connected to the recei:ver chamber 42 via the necked-down portion 66 and port 62. Under these circums-tances, the lower side of the piston por-tion 30 is pressurized to force the hammer pis-ton 32 upwardly while air exits through ~he exhaust ports 28. After the large diameter piston portion 30 closes. off~.the exhaust ports 28, the air captured above it cushions the upward travel of the hammer piston~
. 20 Upward movement of the hammer pis-ton will continue until the space above piston portion 30 is in communication with the upper receiyer chamber 20 via the necked-down portion 64 and th~ ports 56. Now fluid under pressure is admitted to the top side of the large di`ameter p.iston portion 30, thereby forcing it downwardly; while air is again exhausted through the exhaust ports 28. Af ter the lower edge of the piston por-tion 30 closes of f the exhaust por-ts 28, the air beneath the pis-ton portion 30 cushions the dcscent of the piston until i-ts underside is again in communication with the receiver chamber 42, whereupon the cycle is repea-ted.
mab/` ' ~L8~
With the arrangement shown, the relativel~ large receivers 20 and 42 dampen any pressure fluctua-tions in the line and, at the same time, assure availabilit~ of air under pressure on demand from the valves. A-t the same time, and by virtue of the fact that the receivers are intercomlec-ted by the tubes 50, no machining of the cyl:inder 26 is required other -than the formation of the exhaust ports 28.
Mounted on the lower housing 12 is a pneumatic or air motor 68 having two lnlet ports connected -through -tubes lQ 70 and 72 and openings in a flange 74 of housing 10 to fittings 76 and 78 wh.ich communicate with nipples 80 and 82 on the other side of the cup~shaped housing 16. The nipples 80 and 82, in turn, are adap-ted to be connec-ted through suitable valYing, not shown, to a source of fluid under pressure. When it is desired to rotate the pneumatic-motor 68 in one direction, for example, air under pressure will - flow in-to the motor through tube 70; whereas, when the reverse direction of rota-tion is desi~red, air under pressure will flow into the motor -through tube 72. This air wi-th en-trained oil is exhaustecl from the l~otor through an annular passage-way 84 e The output shaft 86 of the fluid motor 68 i~s journaled in suitable beari`ngs as shown and carries a pinion gear 88 whi.ch meshes wi-th a clus-ter gear 90, also carried within suitable beari.ngs. The cluster gear 90, in turn, drives a bushing gear 92 whi~ch forms an integral part of a circular bushing 94 carried on taper bearings 96 and 98 within the housing 12. The bushing 94 is provided with an internal, mab/,' ¦
splined sleeve 100 which meshes with a splined strikinc3 bar 102. As the bushing 94 is rotated within bearings 96 and 98, so also will the striking bar 102 by vixtue of its splined connection to the sleeve 100. At the same time, the striking bar 102 can be reciprocated by virtue of its splined connection to the sleeve 100 as it is repeatedly struck by the lower end of the hammer piston 32 which, as explained above, continually reciprocates as long as fluid under pressure is supplied to the receiver chambers 20 and 42.
The gears 88, 90 and 92 are carried within a gearbox 101 provided with seals at 103, 105 and 107. ~il is poured into the gear box which is sealed by the foregoing seals.
Extending through the hammer piston 32, as well as the striking bar 102, is a tube 104 provided with suitable O-ring seals as shown. Tube 104 is connected at its upper end to an inlet port 106 adapted for connection to a source of cleaning fluid, such as water. The fluid passes downwardly through the tube 104, the striking bar 102 and the drill rod itself to the drill bit where it is discharged onto the material being bored. Bushing 94 is held in place by a ring nut 108 in engagement with an annular bushing 110 which abuts the lower end of bushing 94.
The above-described pneumatic motor is also described and is claimed in above-identified parent application 367,475.
Re~erting again to the air motor 68, it will be remembered that exhaust air and oil from khe motor are S~
discharged into annular chamber 84. From this annular chamber, it is directed through passageway 111 in the bushing 12 into a ~pace 114 surrounding the upper end of the striking bar 102 and the lower end of the reduced-diameter portion 36 of the hammer piston 32. This serves to lubricate the reciprocating parts in this portion of the assembly. Part of the exhaust air will escape through opening 115 in the upper wall of housing 12; while the remainder will leak pas~ the striking bar 102 to the atmosphere along the path of the arrows shown in Fig. 1.
Surrounding the hammer piston assembly 14 and the pneumatic motor 68, and carried between grommets 116 and 118, is an aluminum sheath 120 provided at one point around its periphery with an opening 122. Air exhausted through the ports 28 enters the space enclosed by the sheath 120 and thence passes out through the opening 122, the space within the sheath acting to muffle the exhaust of air from the device. Air passing through opening 115, of course, also enters the space enclosed by sheath 120.
Although the invention has been shown in connection with a certain specific embodiment, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.
~/
sb/l
This i.s a division of copending Canadian Patent application serial number 367,475, filed December 23, 1980.
In the past, pneumatic motors for rock ~rills and the like have been provided wherein the hammer piston includes reduced-diameter portions extending axially on opposite sides of an enlarged central piston portion. The reduce~-diameter portions include reduced area sections which act as inlet valve means for valving motive air to the piston head from both ends of the cylinder. On example of such a pneumatic motor can be found by reference to U~S. Patent No. 1,264,217, issued April 30, 1918.
The present invention resides in a pneumatic rock drill assembly of the type in which a drill rod is carried by a striking bar which is repeatedly struck by a reciprocating piston and wherein the striking bar is carried for reciprocation by a rotatable bushing connected through a gear train enclosed within a gearbox to a pneumatic motor. Passageway means is provided in the rock drill assembly for directing exhaust air and oil from the pneumatic motor to the periphery of the striking bar only to lubricate the same.
The above and othe.r features of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings which form form a part of this specification, and in which:
~
sb/~G' Figure 1 is a vertical cross-sectional view of the pneumatic motor, rock drill assembly of the inventio,n;
Fig. 2 is a top view of the apparatus shown in Fig. l; and Fig. 3 is a cross-sectional view taken along line III-III of Fig. 2 showing one of two tubes which interconnect receivers at opposite ends of the reciprocating piston assembly.
With reference now to the drawings, and particularly to Figs. 1 and 2, there is shown a rock drill assembly comprising an upper housing 10, a lower housing 12 and an intermediate hammer piston and cylinder assembly, generally indicated by the reference nlImeral 14. The upper housing 10 includes a cup-shaped member 16 into which i5 fitted a generally circular bushing part 18 to provide a first or upper receiver chamber 20 adapted for connection to a source of external aix pressure via an inlet port 22. Carried on the sb/j~
~84L~
lower housing 12 is a second generally circular bushing part 24; and between the parts 18 and 24 is a cylinder section 26 comprising a simple -tube having exhaust ports 28 formed -therein.
Reciprocable within -the cylinder 26 is the large diameter por-tion 30 of a hammer pis-ton, generally indicated by the reference numeral 32. Extending axially on opposite sides of the enlarged-diameter piston portion 30 are reduced-diameter piston portions 34 and 36. Piston portion 34 reciprocates wi-thin a sleeve or liner 38 inserted into a bore in the part 18. Simi~larly, pis-ton portion 36 recipro-cates within a sleeve or liner 40 inser-ted into a bore in the part 24. Also formed in the par-t 24 and surrounding the liner 40 is a second receiver chamber 42.
As best shown in Pi~s. 2 and 3, the housing portion 16 is formed with a si.de extension 44 having a lower flange 46 which rests on the periphery of part 18. Formed in the flan~e 46 are two openings 48 which receive -thin-walled tubes 50, one of which is shown in Fig. 3~ The other ends of the thin-walled tubes 50 are connec-ted to an elbow 52 which connects the lower ends of the -tubes wi-th ports 54 extending through the pa.rt 24 and communicating with the lower receiver chamber 42. Thus, the tubes 50. interconnec-t the upper and lower receiver chambers 20 and 42 without the necessity for machinin~ passageways i~n -the cylinder assembly. At -the same time, the tubing permits the cylinder 26 for the large diameter piston 30 -to comprise a simple tube having only the exhaust por-ts 28 formed therein.
The upper liner 38 in part 18 is provided with mab/ ~
ports 56 which con~unicate wi.-th an ~nnular passageway 58 formed in -the part 18. The passageway 58, in turn, i5 connected through por-t 60 to the recei~er chamber 20.
Similarly, the lower receiver chamber 42 is aclapted to be connec-ted -to the interior of -the cylinder formed by the liner 40 -through ports 62~ I-t will be noted that the reduced-diameter pis-ton portions 34 and 36 have necked down areas or portions 64 and 66. ~hese cooperate with -the por-ts 56 and 62 to alternately valve motive air to the upper and lower sur-~aces of the large diame-ter pi~ston portion 30. That is, with the hammer piston 32 in the position shown in F~g. 1, the lower cide o~ the la.rge didmeter pis-ton portior 30 is connected to the recei:ver chamber 42 via the necked-down portion 66 and port 62. Under these circums-tances, the lower side of the piston por-tion 30 is pressurized to force the hammer pis-ton 32 upwardly while air exits through ~he exhaust ports 28. After the large diameter piston portion 30 closes. off~.the exhaust ports 28, the air captured above it cushions the upward travel of the hammer piston~
. 20 Upward movement of the hammer pis-ton will continue until the space above piston portion 30 is in communication with the upper receiyer chamber 20 via the necked-down portion 64 and th~ ports 56. Now fluid under pressure is admitted to the top side of the large di`ameter p.iston portion 30, thereby forcing it downwardly; while air is again exhausted through the exhaust ports 28. Af ter the lower edge of the piston por-tion 30 closes of f the exhaust por-ts 28, the air beneath the pis-ton portion 30 cushions the dcscent of the piston until i-ts underside is again in communication with the receiver chamber 42, whereupon the cycle is repea-ted.
mab/` ' ~L8~
With the arrangement shown, the relativel~ large receivers 20 and 42 dampen any pressure fluctua-tions in the line and, at the same time, assure availabilit~ of air under pressure on demand from the valves. A-t the same time, and by virtue of the fact that the receivers are intercomlec-ted by the tubes 50, no machining of the cyl:inder 26 is required other -than the formation of the exhaust ports 28.
Mounted on the lower housing 12 is a pneumatic or air motor 68 having two lnlet ports connected -through -tubes lQ 70 and 72 and openings in a flange 74 of housing 10 to fittings 76 and 78 wh.ich communicate with nipples 80 and 82 on the other side of the cup~shaped housing 16. The nipples 80 and 82, in turn, are adap-ted to be connec-ted through suitable valYing, not shown, to a source of fluid under pressure. When it is desired to rotate the pneumatic-motor 68 in one direction, for example, air under pressure will - flow in-to the motor through tube 70; whereas, when the reverse direction of rota-tion is desi~red, air under pressure will flow into the motor -through tube 72. This air wi-th en-trained oil is exhaustecl from the l~otor through an annular passage-way 84 e The output shaft 86 of the fluid motor 68 i~s journaled in suitable beari`ngs as shown and carries a pinion gear 88 whi.ch meshes wi-th a clus-ter gear 90, also carried within suitable beari.ngs. The cluster gear 90, in turn, drives a bushing gear 92 whi~ch forms an integral part of a circular bushing 94 carried on taper bearings 96 and 98 within the housing 12. The bushing 94 is provided with an internal, mab/,' ¦
splined sleeve 100 which meshes with a splined strikinc3 bar 102. As the bushing 94 is rotated within bearings 96 and 98, so also will the striking bar 102 by vixtue of its splined connection to the sleeve 100. At the same time, the striking bar 102 can be reciprocated by virtue of its splined connection to the sleeve 100 as it is repeatedly struck by the lower end of the hammer piston 32 which, as explained above, continually reciprocates as long as fluid under pressure is supplied to the receiver chambers 20 and 42.
The gears 88, 90 and 92 are carried within a gearbox 101 provided with seals at 103, 105 and 107. ~il is poured into the gear box which is sealed by the foregoing seals.
Extending through the hammer piston 32, as well as the striking bar 102, is a tube 104 provided with suitable O-ring seals as shown. Tube 104 is connected at its upper end to an inlet port 106 adapted for connection to a source of cleaning fluid, such as water. The fluid passes downwardly through the tube 104, the striking bar 102 and the drill rod itself to the drill bit where it is discharged onto the material being bored. Bushing 94 is held in place by a ring nut 108 in engagement with an annular bushing 110 which abuts the lower end of bushing 94.
The above-described pneumatic motor is also described and is claimed in above-identified parent application 367,475.
Re~erting again to the air motor 68, it will be remembered that exhaust air and oil from khe motor are S~
discharged into annular chamber 84. From this annular chamber, it is directed through passageway 111 in the bushing 12 into a ~pace 114 surrounding the upper end of the striking bar 102 and the lower end of the reduced-diameter portion 36 of the hammer piston 32. This serves to lubricate the reciprocating parts in this portion of the assembly. Part of the exhaust air will escape through opening 115 in the upper wall of housing 12; while the remainder will leak pas~ the striking bar 102 to the atmosphere along the path of the arrows shown in Fig. 1.
Surrounding the hammer piston assembly 14 and the pneumatic motor 68, and carried between grommets 116 and 118, is an aluminum sheath 120 provided at one point around its periphery with an opening 122. Air exhausted through the ports 28 enters the space enclosed by the sheath 120 and thence passes out through the opening 122, the space within the sheath acting to muffle the exhaust of air from the device. Air passing through opening 115, of course, also enters the space enclosed by sheath 120.
Although the invention has been shown in connection with a certain specific embodiment, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.
~/
sb/l
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a pneumatic rock drill assembly of the type in which a drill rod is carried by a striking bar which is repeatedly struck by a reciprocating piston and wherein the striking bar is carried for reciprocation by a rotatable bushing connected through a gear train enclosed within a gearbox to a pneumatic motor, the combination of passageway means in the rock drill assembly for directing exhaust air and oil from the pneumatic motor to the periphery of said striking bar only to lubricate the same.
2. The pneumatic rock drill assembly of claim 1 wherein said striking bar is reciprocable within said rotatable bushing by means of a splined connection thereto.
3. The pneumatic rock drill assembly of claim 1 wherein said passageway means bypasses the gearbox such that air and oil frorn the pneumatic motor are not directed into the gearbox.
4. The pneumatic rock drill assembly of claim 3 wherein said bushing is provided at its upper end with an enlarged diameter area portion which surrounds the upper portion of said striking bar and wherein said exhaust air and oil are directed by said passageway means into said enlarged diameter area portion.
5. A lubrication system for the striking bar of a pneumatic rock drill assembly of the type having a non-coaxial drill rotation motor and of the type in which a drill rod is carried by said striking bar which is repeatedly struck by a reciprocating piston and wherein said striking bar is carried for reciprocation by a rotatable bushing connected through a gear train enclosed within a oil flooded gearbox to a pneumatic motor, said gearbox sealed to prevent loss of said oil, said system comprising: a passageway means in said rock drill assembly for directing exhaust air and oil from the pneumatic motor to the outer circumferential periphery of said striking bar to lubricate the lower end thereof.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/110,587 US4340121A (en) | 1980-01-09 | 1980-01-09 | Pneumatic rock drills |
| US110,587 | 1980-01-09 | ||
| CA000367475A CA1167332A (en) | 1980-01-09 | 1980-12-23 | Pneumatic motor for rock drills and the like |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000367475A Division CA1167332A (en) | 1980-01-09 | 1980-12-23 | Pneumatic motor for rock drills and the like |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1184449A true CA1184449A (en) | 1985-03-26 |
Family
ID=25669216
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000448389A Expired CA1184449A (en) | 1980-01-09 | 1984-02-27 | Pneumatic motor for rock drills and the like |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1184449A (en) |
-
1984
- 1984-02-27 CA CA000448389A patent/CA1184449A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |