US3858666A

US3858666A - Continuous rotation rock drill

Info

Publication number: US3858666A
Application number: US293093A
Authority: US
Inventors: Edward A Bailey; Walter D Fish; Rene Pertusio
Original assignee: Edward A Bailey; Walter D Fish; Rene Pertusio
Current assignee: Cannon Industries Inc
Priority date: 1972-09-28
Filing date: 1972-09-28
Publication date: 1975-01-07
Anticipated expiration: 1992-01-07
Also published as: CA975350A; AU6058573A; AU467027B2; ZA737428B; IT997300B

Abstract

A rock drill having a drill rotation motor coaxial with the percussion motor hammer piston and surrounding the striking bar of the drill.

Description

Bauifley et a1. 1 1 Jan. 7, 1975 [54] CONTIINIUOUS ROTATION ROCK DRILL 1,846,817 2 1932 Smith, Jr 173 105 x 1 1 Edward Bafley, 2, 5131???? 15/1323 5213119711333: 13311:..131123 BOX 37, Newport, -H- 0377?; 3,059,618 10/1962 Osgood 173/105 x Walter Fish, 14 Hlghlandvlew 3,116,666 1/1964 36611 418/196 x Rd, Claremont, NH. 03743; Rene 3,191,693 6/1965 Lincoln 173/105 X Pertusio, PO. Box 757, Goshen, 3,528,345 9/1970 Rumsey 1 418/196 X 03752 3,666,024 5/1972 Beaumont. 173/105 3,685,593 8/1972 Amtsberg 173/105 X [22] F11ed: Sept. 28, 1972 FOREIGN PATENTS OR APPLICATIONS [21] Appl' 293393 568,813 4/1945 Great Britain 173/59 [52] US. Cl 173/59, 173/78, 173/105, P i Examiner- Ernest R Purser 7 173/DIG- 2, 418/1 Assistant ExaminerWi11iam F. Pate, 111 [51] Int. Cl B25d 9/00 Atto ney, Agent, or FirmH0ward E, Sandler [58] Field of Search 173/105, 106, 107, 108,

173/59; 418/196, 227 [57] ABSTRAQT [56] References Cited A rock drill having a drill rotation motor coaxial with UNITED STATES PATENTS the [JEFCiJSSlOH motor hanimer piston and surrounding 1 the strikmg bar of the dull. 1,459,402 6/1923 Johnson 173/108 1,605,712 11/1926 Gilman 173/105 9 Claims, 4 Drawing Figures PATENTED JAN 7 I975 SHEEY 10F 2 1 CUNTINIUOUS ROTATION ROCK DRILL In the field of rock drill engineering it is well known to provide a rock drill apparatus having a percussion motor with a reciprocating hammer piston and an independently operable drill rotation motor for rotating the striking bar of the rock drill and thereby providing rotation of the drill steel and bit.

In the rock drill apparatus of the prior art the drill rotation motor has been mounted generally alongside the percussion motor in a portion of the housing extending laterally from the outer surface of the percussion motor cylinder. The present invention provides an independently operable rotation motor having the main drive member and gear reduction elements coaxial with or symmetrically distributed around the striking bar of the rock drill so that the rock drill housing is free of any lateral extension for the rotation motor. This design yields obvious advantages over prior designs in a better balanced apparatus, reduced space requirements for the housing, better muffler arrangement, multiple tooth engagement of the drive gearing and better lubrication of the striking bar and associated rotating parts.

These and other advantages and objects of the present invention will be more readily appreciated upon consideration of the following description and drawings in which:

FIG. 1 is a median sectional view of a rock drill constructed according to the principles of this invention taken substantially on line ll-1 of FIG. 2 looking in the direction indicated by the arrows;

FIG. 2 is a three dimensional view of the rock drill of FIG. 1 on a smaller scale, with portions broken away to show details of the rotation motor and planetary drive;

FIG. 3 is a sectional view taken substantially on line 33 of FIG. 2 looking in the direction indicated by the arrows;

FIG. 4 is a fragmentary sectional view taken substantially on line 4-4 of FIG. 1 looking in the direction indicated by the arrows.

In FIG. 1 there is shown a sectional view of a percussive rock drill generally indicated at of the valveless type described and shown in US. Pat. No. 3,666,024 and provided with a hammer piston 12 having a stem portion 14 with passageways therein for controlling the compressed air which produces reciprocation of the hammer piston 12 within a cylinder body 16 having a back head 17 as more fully described and illustrated in the above cited US. patent.

Coaxial with the hammer piston 12 is an elongated generally cylindrical striking bar 20 extending inwardly from beyond the forward end of the rock drill 10 (to the right as seen in FIGS. 1 and 2) through approximately half the length of the drill It) to a point within the drill where it may be struck by the hammer piston 12 upon reciprocation thereof. The striking bar 20 has external splines 21 in a central portion to provide a slidable driving engagement with internal splines 23 of a chuck 22 having small external splines 24 on the forward end portion thereof for a purpose to be disclosed.

An elongated, hollow, generally cylindrical planetary carrier member 28 internally drivingly receives the chuck 22 along with a chuck bushing 26 rearwardly abutting the chuck 22 to slidably support the rearward end of the striking bar 20. Forward and rearward end portions of the carrier member 28 are rotatably supported against both radial and axial forces by suitable bearings as for instance the tapered roller bearings shown as

elements

30 and 31, front and rear bearings respectively. The

bearings

31 and 30 are respectively mounted in a yoke portion 34 and a planetary gear cover portion 36, respectively, of the body of the rock drill l0, rigidly secured together and to the rock drill body by elongated threaded members such as side rods 38 (see FIG. 3) and side rod nuts 39 abutting a front cover portion 40 of the rock drill body to removably secure the

portions

34, 36 and 40 in coaxial abutting relationship as well as the cylinder body 16 with the back head 17.

A wide flanged air motor bearing support 42 having a hub portion radially spaced from and surrounding an intermediate portion of the carrier member 28 is assembled with an air motor gear housing 44 and an air motor front plate 46 to form the body of the rotation motor 47 of the instant invention. Mounted on the hub portion of the air motor bearing support 42 is a pair of needle type roller bearing assemblies 48 to rotatably support an air motor drive gear 50 hereinafter more completely described but having (as been seen in FIG. 1) a forwardly extending externally toothed portion 52 which is the driving sun gear for a set of planetary speed reduction gearing incorporating the before mentioned carrier member 28 on which are rotatably mounted a plurality of pinions 54 (see FIG. 2) in toothed engagement with the gear portion 52 and the internal teeth of a fixed planetary gear 56 rigidly secured between the yoke 34 and planetary gear cover 36 and rigidly secured against rotation by the side rods 38 extending through notches 57 in the exterior periphery of the fixed gear 56.

In FIG. 3 the air motor drive gear is seen to have on its periphery a plurality of teeth of two different sizes namely large teeth 60 and small teeth 62. The large teeth 60 (8 are shown) are spaced apart approximately three times the normal pitch for that size of tooth and the small teeth 62 are formed in between the large teeth 60 (six small teeth 62 are shown between each pair of large teeth 60). The drive gear 50 and the large teeth 60 thereon are suitably sized to rotate with very small clearance within the central bore 45 of the gear housing 44 to minimize leakage of air between the large teeth 60 and the bore 45 when the rotation motor 47 is operating.

Meshed with the drive gear 50 is a pair of air motor idler gears or pinions 64 provided with toothed spaces complementary to the large and

small teeth

60 and 62 of drive gear 50 so that the idler gear 64 show a pair of large tooth spaces 65 with small tooth spaces 66 therebetween of a number equal to the number of small teeth between each two large teeth on the drive gear 50. The purpose of the large teeth on the drive gear 50 is to provide air capacity for a powerful rotation motor while the small teeth on the

gears

50 and 64 make for smooth operation of the pinion 64 not possible with gear teeth the size of the large teeth 60.

As best seen in FIG. 2 the gears 50 and 65 have a face width much greater than normal for this size gearing for the purpose of providing more air capacity to increase the power of the rotation motor.

It is to be noted that the above described construction of the air motor and the planetary reduction gear set provides that the carrier member 28 if mechanically isolated from the rotation motor 47 so that damage to or failure of one of these will not cause trouble in the other member.

As best seen in FIG. 2 three fluid conducting elements, illustrated as

hoses

70, 71 and 72, respectively communicate with an air manifold 74 rigidly secured to the side of the yoke 34 of rock drill to provide compressed air to the rock drill 10. As will be seen the central hose 71 is larger than the other two hoses and is used for the supply of air to the percussion motor to reciprocate the piston 12 backward and forward in the cylinder body 16 in a well known manner as set forth in the above cited US. patent. The supply of air through the hose 71 is controlled by usual valve means (not shown) communicating with a source of compressed air such as a compressor. Other control means (also not shown) are used to selectively connect

hose

70 or 72 to the source of compressed air and simultaneously to connect the other of the two

hoses

70 and 72 to the outside atmosphere for exhausting of a portion of the compressed air furnished to the rotation motor as hereinafter made plain.

The manifold 74 is provided with passageways (not shown) communicating the

hoses

70 and 72 with respective passageways in the front yoke 34 which in turn communicate with

respective bores

76 and 77 through the bearing support 42 which in turn communicate with open

sided bore portions

76 and 77 in the gear housing 44 which communicate with the spaces between the drive gear 50 and the bore 45 of the housing 44 adjacent opposite sides of the pinion 64 (see FIG. 3).

Referring again to FIG. 4 it is to be seen that

bores

76 and 77 are cross connected by suitable

air conducting grooves

80 and 81 in the face of bearing support 42 with

similar bores

78 and 79 respectively through the flange portion of bearing support 42 which in turn communicate with partial bores 78' and 79, respectively, on opposite sides of a second pinion 64' communicating with the space between drive gear 50 and the bore 45 on opposite sides of the second pinion 64' so that when pressure fluid or compressed air is furnished to hose 70 (see FIG. 2) such compressed air will be provided to the

bores

76 and 78 and the partial bores 76 and 78' and the spaces between the drive gear 50 and the bore 45 on the left hand side of gear 64 as seen in FIG. 3 and on the right hand side of gear 64' as seen in that figure. Thus, with pressure furnished as above stated the drive gear 50 will be rotated in the direction shown by arrow 68 in the middle of FIG. 3.

When the hose 70 is connected to compressed air the hose 72 will be connected to the atmosphere which in turn connects the

bores

77 and 79; and the partial bores 77' and 79 and the spaces between drive gear 50 and the bore 45 on the right hand side of gear 64 and on the left hand side of gear 64'; to the atmosphere for the purpose of exhausting air which travels around the exterior of the pinion 64 and 64' during rotation under the force of the compressed air.

Two other partial bores 84' and 85 left and right hand in FIG. 3 and right and left hand bores 84 and 85, respectively in FIG. 4 communicate from the spaces between the drive gear 50 and the bore 45, through the flange of the bearing support 42, with exhaust passages 88 and 89 in the front yoke 34 which in turn are pennanently connected to internal volume 90 ofa muffler 91 surrounding the cylinder body 16 of the rock drill l0. Whenever air is furnished to either

bores

76 and 78 or bores 77 and 79 the compressed air after pushing the large gear teeth 60 on the drive gear 50 past the exhaust port 84' or 85' air will be exhausted directly from the space between the drive gear 50 and the bore 45 to the muffler volume 90 wherein the sound of the exhaust will be greatly attenuated before coming into contact with the ambient atmosphere to provide sound level reduction in a well known manner.

It should be readily apparent that provision of compressed air to hose 72 will provide compressed air to bores 77 and 79 and

partial bores

77 and 79 with resultant force reversal to provide for reverse rotation of the drive gear 50. When the hose 72 is connected to the pressure side the hose will be connected to atmosphere and exhaust by way of

partial bores

78 and 76 through the

bores

78 and 76 and the hose 70 will be similar to the exhaust through 72 during forward rotation. The main exhaust will still be through the bore portions 84' and and the

bores

84 and 85 to passageways 88 and 89 through muffler volume during reverse rotation.

Referring again to FIG. 1 it will be seen that a passageway 92 extends obliquely forwardly and inwardly from passageways 88 and 89, respectively, to the roller portion of bearing 31. The passageways 92 provide for the use of some exhaust air bled off from the passageways 88 and 89 to travel through the bearing 31 and the spaces around and between the striking bar 20 and the chuck driver 22 and chuck bushing 26 and forwardly through the bearing 30 to provide cooling and lubrication (from a well known air line oiler) to the bearings and other rotating and sliding parts in a very desirable manner.

As regards the operation of the rock drill 10 of this invention the above described rotation of the air motor drive gear 50 is of course transferred to the sun gear 52 and the pinions 54. The pinions 54 being in engagement with the stationary gear 56 will travel around the inner teeth of the gear 56 and carry with them the carrier member 28 which is in turn drivingly engaged by means of splines 24 with chuck 22, the splines 23 of which slidingly engage the splines 21 of the striking bar 20 to provide the desired rotation thereof.

Such rotation is of course transferred through coupling means (not shown) to drill steels and drill 'bits connected to the rock drill 10 in a well known manner to provide for the rotation of the drill during drilling and also to provide rotation for threadingly engaging and disengaging the couplings and drill steels as desired.

Although a particular embodiment of the rock drill of this invention has been hereinabove described, it is to be realized that other embodiments of the principles of this invention are envisioned and possible. It is therefore respectfully requested that this invention be interpreted as broadly as possible within the scope of those principles.

What is claimed is:

l. A pressure fluid actuated rock drill comprising: an elongated cylinder body; a piston member reciprocable in said cylinder body along the central longitudinal axis of said body; passageway means adapted to be con-' nected to a fluid pressure source to supply fluid under pressure to reciprocate said piston member in said body; an elongated striking bar slidably rotatably mounted in said body and coaxial therewith to receive blows from said piston; a fluid operated reversible drill rotation motor symmetrical about said axis and in driving communication with a striking bar chuck driver for the selective rotation of said striking bar in opposite directions about the longitudinal axis thereof; and speed reduction gear means including a set of planetary gears coaxial with said rotation motor and in driving engagement between said rotation motor and said chuck driver.

2. A rock drill as specified in claim 1 wherein said passageway means include cooperable passageways in said hammer piston and in said cylinder body.

3. The rock drill as specified in claim 2 wherein said piston member comprises a head portion and an elongated stem portion and said passageways in said piston member are in said stem portion.

4. The rock drill as specified in claim 1 wherein said rotation motor comprises; a double pitch driving gear coaxial with said body, a plurality of double pitch driving pinions equidistant from said axis, and fluid conducting passageway means for rotation of said striking bar in either a forward or a reverse direction.

5. The rock drill as specified in claim 4 wherein said speed reduction gear means is supported on antifriction bearing means at each end of said motor and said driving gear is supported independently of said speed reduction gear means.

6. The rock drill as specified in claim 5 wherein said support of said driving gear includes antifriction bearing means.

7. The rock drill as specified in claim 1 additionally comprising a muffler and said rotation motor has primary exhaust connections permanently connected to the interior of said muffler.

8. The rock drill as specified in claim 7 wherein said rotation motor has anti-friction bearings at both axial ends thereof with secondary exhaust passageway means conducting exhaust fluid from said rotation motor to said bearings.

9. The rock drill as specified in claim 8 wherein said secondary exhaust passageway means also communicate with the exterior of said striking bar.

Claims

1. A pressure fluid actuated rock drill comprising: an elongated cylinder body; a piston member reciprocable in said cylinder body along the central longitudinal axis of said body; passageway means adapted to be connected to a fluid pressure source to supply fluid under pressure to reciprocate said piston member in said body; an elongated striking bar slidably rotatably mounted in said body and coaxial therewith to receive blows from said piston; a fluid operated reversible drill rotation motor symmetrical about said axis and in driving communication with a striking bar chuck driver for the selective rotation of said striking bar in opposite directions about the longitudinal axis thereof; and speed reduction gear means including a set of planetary gears coaxial with said rotation motor and in driving engagement between said rotation motor and said chuck driver.