US2068661A - Feeding mechanism for rock drills - Google Patents

Description

5 Sheets-Sheet 1 J. C. CURTIS FEEDING MECHANISM FOR ROCK DRILLS Filed Nov. 29, 1935 Jan. 26, 193?,

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J. 26, 1937. .1. c. CURTIS FEEDING MECHANISM FOR ROCK DRILLS Filed NOV. 29, 1935 3 Sheets-Sheet 2 ./oH/y c: cw? r/.s

INVENTOR ATTORNEY Jan. 25, 1937. J, C, CUR-ns 2,068,661

FEEDING MECHANISM FOR ROCK DRILLS Filed Nov. 29, 1955 5 Sheets-Sheet 3 JOHN C. CURTIS INVENTOR ATTORNEY Patented Jan. 26, 1937 'UNITED STATES PATENT OFFICE 2,068,861 FEEDING MECILANISM` FOB ROCK DRILLS John C. Curtis, Garlield Heights, Ohio, asslgnor to The Cleveland Rock Drill Company, Cleveland, Ohio, a corporation of Ohio I Application November 2,9, 1935, Serial No. 52,135

23 Claims.

This invention relates broadly to rock drills, but more particularly to feeding mechanism for rock drills of the pei'cussive type wherein the drill is siidably mounted on a suitable support or shell, and is automatically fed toward or away from the work. y

One object of this invention is to provide a rock drill with a new and elilcient feeding mechanism capable vof feeding the rock drill toward or away from the work.

Another object of this invention is to produce a feeding'mechanism for rock drill whereby the latter is capable ofrelatively long feed toward or away from the work, without increasing the overall length of the assembly.

Another object of this invention is to utilizev the force ofthe jars imparted to the rock drill due to the reversal of the piston strokes therein, for feeding the rock drill in either direction.

Other objects more or less ancillary to the foregoing and the manner in which the various objects are attained,` reside in the specific construction and aggroupment of the elements peculiar to this structure, as will become apparent .from a more complete examination of this specication, in the claims of which there are assembled certain speciiic combinations of parts and specic constructions indicative of the scope and spirit of the invention.

In the drawings which illustrate a preferred form of the invention:

Fig. 1 is a side elevational view of a rock drill having the invention applied thereto, the support being shown in section to illustrate details of construction.

Fig. 2 is an enlarged cross sectional view taken.

in a plane indicated by line 2-'2 in Fig. 1.

Fig. 3 is an enlarged cross sectional view taken in a plane indicated by line 3 3 in Fig. 1.

Fig. 4 is a fragmental longitudinal sectional view taken in a plane indicated by line 4 4 in Fig. 2.

Fig. 5 is a view similar to Fig. 4 illustrating a portion Vof the mechanism shown in the latter with some parts shown in different position.

Fig. 6 is a cross sectional view taken in a plane indicated by line 6-6 in Fig. 4.

Fig. 7 represents a portion of the mechanism illustrated in Fig. 4, with the valve shown in different position.

Fig. 8 is a cross sectional view taken in a plane indicated by line 8 8 in Fig. 4.

Fig. 9 is a top plan view of the portion oi the mechanism shown in Fig. 4.

Fig. 10 is a cross sectional view taken in a piane indicated by line IIl-Ili in Fig. 3.

Fig. 11 is a cross sectional view taken in a plane indicated by line II-II in Fig. 3.

Fig. 12 is an enlarged cross sectional view taken 5 in a plane indicated by line I2-I2 in Fig. 4.

Fig. 13 is a cross sectional view taken in a plane indicated by line I3-I3 in Fig. 4.

Fig. 14 is an enlarged' sectional view taken in a plane indicated by line Il--II in Fig. 4.

Referring to the drawings, I5 represents a rock drill or drilling motor of the uid actuated percussive type which is Slidably mounted within guideways I6 formed in the upper end of the side walls of a shell or support I1. Transversally 15 disposed through the back head I8 of the motor I5, there is a cylindrical bore I3 having a throttle valveV 20 rotatable therein by the medium of' a handle 2l. To one end of the bore I9 is detachably aillxed a-motive fluid connection 22 through 20 which motive fluid may be admitted into a motive uid chamber 23 formed within the throttle valve 20. Leading from the chamber 23 to the peripheral wall of the throttle valve 20, there are two radially disposed ports 24 and 25, which are capa- 25 ble of communication with a passage 26 formed in the head I8 for admitting motive uid into the motor: I5. Closer to the free end of the throttle valve, the latter is provided with a groove 21 extending partly around the throttle valve. 'I'his groove is in constant communication with the chamber 23 through a radially disposed port 28.

The back head I8 has also incorporated therein a valve mechanism comprising a valve casing 29 formed with a cylindrical bore 30 extending 3- therethrough and emerged at one end to form a counterbore 3|. Provided around the valve casing 29, there is a groove 32, which opens into the lbottom of the counterbore 3l through small ports 33. Between its ends, the bore 30 is provided with an internal annular groove 34 in constant communication with a port 35. Opening into the extreme end of the bore 30, there is a small port 36 leading to the atmosphere through a port 3l. Slidably mounted within the bore 30, there is a valve 38 having a flange 39 slidable within the counterbore 3i. The flange 39 is transversed by a plurality of small ports I0. Back of the valve casing 29, there is a plate 4I having a. port l2 therethrough to aiord communication of the counterbore 3l with a cavity 43 formed within the head I8, and into which opens the port 35. The annular groove 32 formed around the valve casing 23 is in constant communication with the throttle valve 20 through a port Il, with which the throttle valve groove 21 is capable of communication.

Secured to the back head I8 by the usual side bolts 45, there is a housing 46 having detachably secured thereto by bolts 41, a casing 48. Rotatably mounted within the housing 46 in coaxial alignment with the center axis of the drilling motor i5, there is a stem 49 formed with external splines 58. This stem extends into the casing 48, where it is terminated by an enlargement or head 5|, which is machined to pivotally receive two pawls 52, each having a. spring pressed plunger 53 acting thereon yand carried by the head 5|. 'Surrounding the head 5I, there is a ring 54 rotatable within the casing 48. This ring has its inner wall machined to form ratchet teeth 55 with which the pawls 52 are engageable, while the external wall of the ring is machined to form teeth 56. Slidably disposed within the casing 48 in transversal relation with the stem 49, there is a rack 51 with the teeth 58 thereof meshing the teeth 56v of the ring 54. This rack is also terminated by an-enlarged cylindrical head 59, which is slidably mounted within a cylindrical chamber 68 formed in the casing 48, and within which motive uid may be admitted on one side of the head 59 through a port 6I leading from the cavity 43 provided in the'back head I8 adjacent the valve casing `29. The chamber 68 is also capable of communication with the atmosphere through a small Vent 62. 'Ihe rack 51 is constantly urged toward the left in Fig. 6 by a compression spring 63 interposed between the end of the rack and the end of the bore within which it is disposed.

Mounted on the stem 49 in abutting relation with the head 59 of the former, there is a member or head 64 secured to the stem 49 against rotation by a key- 65. The head 64 also carries pivotally mounted pawls 66 having spring pressed plunger 61 acting thereon. Surrounding the head 64, there is a ring 88 having the inner wall thereof machined to form ratchet teeth 69 with which the pawls 66 engage. The external wall of the ring 68 is formed with a notch 18 adapted to receive the end portion of a plunger 1I which is mounted within a bore 12 formed in the casing 48 in parallel alignment with the rack 51. This bore is closed by a plug 'I3 and has dlisposed therein a relatively heavy compression spring 14 lconstantly urging the plunger 1 I .toward the left in Fig. 8.

siidabiy mounted on the stem 49 there is a' sleeve 15 formed with internal splines 16 meshing with the splines of the stem 49. Intermediate its ends, the sleeve 15 is provided with an external annular groove 11. The sleeve 15 has its right end portion in Fig. 4 terminated by external splines 18 capable of engagement with corresponding internal splines of a bevel gear 19 rotatably mounted in the housing 46 in coaxial alignment with the center axis of the stem 49. This bevel gear is hollowed, and has friction disks 88 disposed therein for engagement with the stationary back head I8. The other end portion of the sleeve 15 is similarly formed with external splines 8| capable of engagement with corresponding internal splines of a bevel gear 82 which is rotatably mounted within the casing 48, and like the gear 19, has friction disks 83 disposed therein. Between the gear 82 and the ring 68, there is interposed a plate 84. The teeth of the bevel gear '19 and 82 are in constant interengagement with the teeth of a third bevel gear 85 mounted therebetween in a manner aiording the shank 86 thereof tc extend through the housing 46 between the side walls of the shell I1. To the portion of this shank protruding from the housing 46 is ailixed by a key 81, a gear 8,8.

Secured to the top o f the housing 46 by bolts 89. there is a cap 98 formed with a vertical bore adapted to rotatably receive the shank portion 9| of a .handle 92, the latter extending horizontally above the housing 46. Depending from the shank 9| of the handle 92 in eccentric relation with the center axis thereof, there is a pin 93 having a segment 94 loosely mounted thereon and extending into the annular groove 11 formed on the sleeve 15. To prevent accidental rotary movement of the handle 92, the peripheral wall of the shank 9| is machined to form a-series of detents 95 adapted to receive the end of a spring pressed plunger 96 slidably mounted within the cap 98.

'Ihe free end portion of the casing 48 is formed with a screw threaded bore 91 adapted to accommodate a packing 98, washer 99 and the head |88 of a small tube I8I. The bore 91 is closed by a plug |82 engaging the washer 99 to compress the packing 98 and assure a fluid tight joint between the tube and housing 48. The tube |8| extends through the stem 49 and the back head I8 into the drilling motor I5, from where it extends into the drill steel in the usual manner for conveying cleansing iluid, such as water, to the cutting edge of the drill steel. Adjacent the plug |82, the casing 48 is provided with a laterally projecting boss |83 which is internally threaded to receive a connection capable of admitting cleansing uid into the bore 91, from where it is free to iiow through the tube I8| vial ports I 84 formed in the plug |82.

Rigidly secured to one side wall of the shell I1 by bolts |85, there is a rack |86 extending sub stantially the full length of the shell. The teetli of this rack are in constant operative engagement with the teeth of the gear 81.

In the operation of the mechanism, the throttle valve 28 may be rotated in a clockwise direction in Fig. 10 sufciently to bring the groove 21 in communication with the port 44. In this instance, the motive fluid admitted into the throttle valve chamber 23 through the motive uid connection 22, will flow into the valve casing annular groove 32 through the throttle valve port 28, groove 21, port 44, from where it is free to ow into the valve casing counterbore 3|, through the ports 33. The motive uid acting on the right side of the valve ange in Fig. 7, will flow through the ports 48, to act on the left side of the flange and maintain the valve in the position shown in Fig. 7. From the valve casing counterbore 3|, the motive uid is free to flow into the cavity 43 through the port 42, from where it is admitted into the cylindrical chamber 68 through the port 6|. Motive uid acting on the left side of the rack head 59 in Fig. 6, will drive the rack 51 against the compression of the spring 63. When the head 59 uncovers the port or vent 62, the motive uid acting on the head will exhaust to the atmosphere, causing thereby-a drop of pressure in the cylindrical chamber 68, and a consequential drop of pressure in the valve casing counterbore 3|. Due to the pressure of--the motive uid acting on the right side of the valve ange 48, the valve will shift in the position shown in Fig. 4, closing thereby the port 42, and permitting the motive iiuid previously admitted into the cylindrical chamber 68 to exhaust therefrom via the port 6|, cavity 43, port 35, lannular groove 34 and ports 36 and 31. The motive fluid now exhausting from the cylindrical chamber 60 will allow the rack 51, due to the effort of the compression spring 63, to return in the position shown in Fig. 6. Simultaneously the motive uid still admitted on the right side of the valve ange 39 through the ports 33, will flow through the ports 40 on the left side of the ange. Since the left side of the flange is of a greater effective area than the right side thereof, the valve will again be shifted in the position shown in Fig. 7, thus readmitting motive fluid into the cylindrical chamber 60 through the port 6|, for driving the rack 51 toward the right in Fig. 6. "From the foregoing it will be understood that when motive fluid is admitted from the throttle valve 20 into the port 44, the rack 51 is auto;

matically reciprocated, thus imparting an os-` cillary motion to the ring 54 due to the engagement .of the rack teeth 58 with the teeth 56 of the ring'54. During the rotary motion of the ring 54 in a counterclockwise direction in Fig. 6, the pawls 52 engaging the ratchet teeth 55 will transmit the rotation of the ring to the stem 49, and consequently to the head 64 secured to the stem by the key 64. In this instance, the pawls 66 carried by the head 64, will simply ride the ratchet teeth 69 of the ring 68, without transmitting rotation to the latter. During the rotation of the ring 54 in a clockwise direction in4 Fig. 6, the pawls 52 carried by the head 5| ofthe stem 49, will simply ride the ratchet teeth of the ring without imparting rotation in a clockwise direction to the stem 49, which rotation is checked by the mechanism shown in Fig. 8. Referring to the latter, it will be seen that the pawls 66 carried by the head 64 keyed on the stem 49 and engaging the ratchet teeth 69, would .transmit the rotary motion of the stem 49 in a clockwise direction to the ring 68. The rotation of the latter however is checked due to the interengagement of the spring pressed plunger 1I with the notch 10, affording thereby a cushion means for checking the rotation of the stem 49 in a clockwise direction.

'Ihe rotation of the stem 49 in a counterclockwise direction is transmitted to the sleeve 15 due to the interengagement of the splines 16 thereof with the splines 50 of the stem. Assume now that the sleeve 15 is to be positioned as shown in Fig. 4, that is, with the splines 18 thereof in engagement with the internal splines of the bevel gear 19. In this instance the rotation of the sleeve in a counterclockwise direction is transmitted to the bevel gear 19, and therefrom to the bevel gear 80 in a clockwise direction. The gear 81 keyed on the shank of the gear 80, will also rotate in a clockwise direction and due to the engagement ofthe teeth thereof with the rack |06, will impart rearward feeding motion to the drilling motor I5. When it is desired to feed the drilling motor toward the Work, the handle 92 may be rotated to cause the segment 94, mounted in eccentric relation with the center axis of the shank handle 9|, to shift the sleeve 15 in the position shown in Fig. 5. In this instance the splines 8| of the sleeve 15 engaging the splines of the bevel gear 82 will transmit rotation to the gear 81 in a counterclockwise direction. The gear 81. engaging the rack |06 `will cause forward feeding motion of the drilling motor l5. v

When it is desired to lock the drilling motor I5 against s'lidable movement relative to the shell l1, the handle 92 may be rotated to position the sleeve 15 in equidistant relation with the bevel gears 19 and 82, causing thereby the engagement `of the sleeve splines 18 with the splines of the' bevel gear 19 and the similar engagement of the sleeve splines 8| with the bevel gear 82. In this instance the rotation of the bevel gears 19 and 82 is prevented due to the engagement of the bevel gear 85, and since this gear is in engagement with the shell I1 through the gear 81 and rack |06, the drilling motor is locked against slidabie movement relative .to the shell.

The speed of the forward or backward feeding motion of the drilling motor may be controlled by the operator applying pressure on the handle 92 to cause-the-forcible engagement of the end of the sleeve 15 with either the friction disks 80 or 83, reducing thereby the speed of rotation of the sleeve, and the consequential speed of rotation of the gear 81.

When the throttle valve 20 is positioned to cause the registration of the throttle valve port 25 with the port 26, the port 44 is closed by the throttle valve, and motive fluid is admitted into the drilling motor I5 for actuating the same, without actuating the feeding mechanism. During the actuation of the drilling motor, the jars resulting from the reciprocation of thehammer piston in the motor, will impart forward and backward slidable motion to the drilling motor relative to the shell |1-. Due to the engagement of the gear 81 with the rack |06, the former will tend to oscillate, thus tending to impart through the bevel gears and the sleeve 15, oscillatory motion to the stem 49. However, due to the mechanism illustrated in Fig. 8 associated with the stem ting a step by step slidable feeding movement of the drilling motor in a corresponding direction. In this instance, the direction of feeding motion of the drilling motor may also be controlled by the handle 92 in the manner previously described.

As previously explained, the feeding mechanism is constructed and arranged in a manner whereby the water tube |0| is free to extend therethrough, thus permitting the plug |02 and Water connection |03 to be located at the outer end of the casing 48. In this location, it is obvious that the plug |02 may readily be removed, and the water tube |0| replaced or inspected without necessitating the removal of a portion of the feeding mechanism.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining, and it is to be further understood that various re-arrangements of parts and modification of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

1. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, a feeding mechanism associated with said motor for imparting forward and backward feeding motion thereto, said mechanism including a rack longitudinally of said support, a gear rotatably carried by said motor in operative engagement with said rack, a power actuated unit included in said mechanism capable of rotation in a single direction, and rotation transmitting means associated with said unit and gear operl able for selectively controlling the direction of rotation of said gear for imparting forward or backward feeding motion to said motor due to the operative engagement aforesaid.

2. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, a feeding mechanism associated with said motor for imparting forward and backward feeding motion thereto, said mechanism including a toothed element longitudinallyof said support, a member movably carried by said motor in operative engagement with the teeth of said element, a power actuated element capable of movement in a single direction, and movement transmitting means between said last element and member operable for selectively controlling the direction of movement of said member for imparting forward or backward feeding motion to said motor due to the operative engagement aforesaid.

v 3. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, an elongated element longitudinally of said support, a member carried by said drilling motor, said element and member having means formed thereon capable of interengagement whereby the rotary motion of said member relative to said element causes the slidable movement of said drilling motor, a mechanism including a gear having a power actuated reciprocable rack associated therewith for imparting oscillatory motion thereto, a component associated with said gear, means for transforming the oscillatory motion of said gear into an intermittent rotary motion of said component in a single direction, and means for transmitting the intermittent rotary motion of said component to said member in either direction, said last means being operable for selectively controlling the direction ofrotation of said member, causing thereby the slidable movement of said drilling motor in one or the other direction.

4. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, an elongated element longitudinally of said support, a member carried by said motor, said element and member having means formed thereon capable of interengagement whereby the rotary motion of said member relative to said element causes the slidable movement of said drilling motor, a mechanism including a gear having a power actuated reciprocable rack associated therewith for imparting oscillatory motion thereto, means for transforming the oscillatory motion of said gear into an intermittent rotary motion of said member in one direction, and means operable for selectively controlling the direction of rotation of said member, causing thereby the slidable movement of said motor in one or the other direction.

5. In a feeding device for a rock drill, the cornbination with a support and a drilling motor slidable thereon, an elongated element longitudinally of said support, a rotatable member carried by said drilling motor, said element and member having means formed thereon capable ofinterengagement whereby the rotary motion of said member relative to said element causes the slidable movement of said drilling motor, a mechanismassociated with said member including a power actuated reciprocable driving element operatively connected with a rotatably driven element for imparting oscillatory motion thereto, means for transmitting the rotary motion of said driven element in one direction to said rotary member in either direction irrespective of the rotary motion of said driven element in the other direction, and means operable for selectively controlling the direction of rotation of said rotary member, thereby controlling the direction of the slidable movement of said drilling motor.

6. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, a reciprocatory piston in the motor imparting jars thereto tending to move the motor in two directions relative to the support, a rack longitudinally of the support, a gear carried by said motor in operative engagementwith said rack, the jars resulting from movement of said motor tending to cause the rotation of said gear in both directions due to its operative engagement with said rack, a mechanism including an element rotatable in a single direction, and means whereby said gear may be connected to said element for preventing the rotation of said gear in one or the other direction, controlling thereby the direction of movement of said motor relative to said support.

. 7. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, a reciprocatory hammer piston in the motor imparting jars thereto to move the motor in two directions relative to the support, a movement resisting mechanism associated with said motor for preventing the movement thereof in one direction, said mechanism including a rack longitudinally of said support, a gear rotatable in both directions in operative engagement with said rack, a member rotatable in a singleY direction, and connection means between said member and gear operable for selectively controlling the direction of rotation of said gear, controlling thereby the direction of movement of said motor relative to said support.

8. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, a reciprocatory hammer piston in the motor imparting jars thereto tending to move the motor in two directions relative to the support, a rack longitudinally of the support, a gear carried by said motor in operative engagement with said rack, the jars resulting from movement of said motor tending to cause the rotation of said gear in both directions due to its operativeV engagement with said rack, a rotatable member having a ratchet mechanism associated therewith for preventing its rotation in one direction, and means for operatively connecting said gear to said member for transmitting the rotation of the former in one direction to the latter and preventing the rotation of said gear in the other direction, controlling thereby the direction of movement of said motor relative to said support.

9. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, a reciprocatory hammer piston in the motor imparting jars thereto tending to move the motor in two directions relative to the support, a rack longitudinally of the support, a gear carried by said motor in operative engagement with said rack, the jars resulting from movement of said motor tending to cause the rotation of said gear in both directions due to its operative engagement with said rack, a member rotatable in only one direction, a duality of elements associated with said gear alternatively eonnectable with said member for transmitting the rotation of said gear in either direction to said member in said one direction, and means operable for selectively connecting one or the other of said elements with said member, controlling thereby the direction of rotation of said gear and the direction of movement of said motor relative to said support.

10. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, a reciprocatory hammer piston in!v the motor imparting jars thereto to move the motor in two directions relative to the support, a movement resisting mechanism associated with said motor for preventing the movement thereof in one direction, said mechanism including a rack longitudinal of the support, a gear in operative engagement with said rack rotatable in either direction, a member rotatable in only one direction, and means for operatively connecting said gear to said member for selectively controlling the direction of rotation of said gear and the direction of movement of said motor relative to said support.

11. In a drilling apparatus, the combination with a support and a drilling motor slidable there- 0n, a reciprocatory hammer piston in the'motor imparting jars thereto to move the motor in two directions relative to the support, and a movement resisting mechanism associated with said motor, said mechanism including a rack longitudinal of the support, a pinion in operative engagement with said rack rotatable in both directions due to the movement of said motor in two directions, gears associated with said pinion normally rotated thereby, and means for locking said gears against rotation, preventing thereby the rotation of said pinion and the movement of said motor relative to said support.

12. In a feeding device for a rock drill, the combination with a support and a drilling Amotor slidable thereon, a feeding mechanism associated with said motor for imparting forward and backward feeding motion thereto, said mechanism including a rack longitudinal of said support, a gear rotatably carried by said motor in operative engagement with said rack, a power actuated element rotatable in' a single direction, transmission means between said element and gear including a member selectively movable in one position for transmitting the rotation of said element to said gear in one direction and in another position for transmitting the rotation aforesaid to said gear in the other direction, controlling thereby the direction of feeding motion of said motor.

13. In a feeding device for a rock drill, the combination with a support having a drilling motor slidable thereon, of a feeding mechanism for said motor including a single rack longitudinal of the support, a gear meshing said rack in a manner whereby the rotation thereof causes the feeding motion of said drilling motor, means for irnparting rotation to said gear in either direction including a uid actuated non-reversible motor, and connectable means between said last motor and gear whereby rotation in either direction may be transmitted to said gear.

14. In a feeding device for a rock drill, the combination with a support having a drilling motor slidable thereon, of a feeding mechanism forsaid motor including a single rack longitudinal of the support, a gear meshing with said rack in a manner whereby the rotation thereof causes the feeding motion of said drilling motor, means for imparting rotation to said gear in either direction including a fluid actuated non-reversible motor, clutch means between said last motor and gear whereby rotation in either direction may be transmitted to said gear, and means for preventing the rotation of said gear in a direction adverse to that of the rotation transmitted thereto by said clutch means, preventing thereby the feeding motion of said drilling motor in a direction adverse to that of its feeding motion.

15. In a feeding device for a rock drill, the combination with a support having a drilling motor slidable thereon, of a feeding mechanism for said motor including a single rack longitudinal of the support, a gear meshing with said rack in a manner whereby the rotation thereof causes the ffeding motion of said drilling motor, means for imparting rotation to said gear in either direction including a power actuated element rotatable in one direction, rotation resisting means associated with said element for preventing the rotation thereof in the other direction, and rotation transmitting means between said element and gear for transmitting the rotation of the former to the latter in either direction, said rotation resisting means preventing the rotation of said gear in a direction adverse to that of the rotation normally transmitting thereto by said rotation transmitting means, preventing thereby the movement of said drilling motor in a direction adverse to that of its feeding motion.

16. In a feeding device for a rock drill, the combination with a support having a rock drill slidable thereon, of a feeding mechanism for said rock drill including a single rack longitudinal of the support, a gear engaging said rack in a. manner whereby the rotation thereof causes the feeding motion of said rock drill, means for imparting rotation to said gear in either direction including a fluid actuated non-reversible motor, rotation transmitting means between said motor and gear for transmitting the rotation of the former to the latter in either direction, a throttle valve for controlling the inlet of motive fluid into said motor, and means independent of the amount of pressure fluid admitted into said motor operable for selectively reducing the rotation speed of said gear. y

1'7. In a feeding device for a rock drill, the combination with a support having a rock drill slidable thereon, of a feeding mechanism for said rock drill including a single rack longitudinal of the support, a gear engaging said rack in a manner whereby the rotation thereof causes the feeding motion of said rock drill, means for imparting rotation to said gear in either direction including a fluid actuated motor, rotation transmitting means between said motor and gear, a handle operable for selectively controlling the direction of rotation of said gear, and means selectively operable upon movement of said handle and independently of said motor for reducing the speed of rotation of said gear.

18. In a feeding mechanism for a rock drill, the combination with a support and a drilling motor slidable thereon in either direction, a duality of elements one carried by the motor and the other longitudinal of the support, interengageable means on said elements whereby the movement of one element relative to the other causes the slidable movement of the motor on the support, a power actuated member normally movable in two directions, and means for transmitting motion from said member to one of said elements in a selective direction for effecting the slidable movement of said motor in one or the other direction.

19. In' a rock drill, the combination with a support and a drilling motor slidable thereon, a gear carried by the motor meshing with a rack carried by the support for causing the slidable movement of the motor upon rotation of the gear. a power actuated element rotatable in a single direction, and connectable means between said element and gear whereby rotation may be imparted to the latter for effecting the slidable movement oi' the motor in either direction.

20. In a feeding device for a rock drill, the combination with a support and a drilling motor slidable thereon, a reoiprccatory piston in the motor imparting jars thereto to move the motor in two directions relative to the support, a duality o1' elements one carried by the motor for movement therewith and the other longitudinally ofthe support, interengaging means on said ele\ ments whereby the movement of the motor causes the rotation of the element carried thereby, a mechanism including a member rotatable in a single direction, and means whereby said Ilast element may be connected to said member for preventing the rotation of the element in one or the other direction, controlling thereby the direction -of movement of said motor relative to said sup- 25 and means whereby said element may be connected to said member for preventing the rotation or the former in one or the other direction, controlling thereby the direction ot movement of said motor relative to the support.

22. In a. feeding device for a rock drill, the combination with a support having a drilling motor slidable thereon, a reciprccatory piston in the motor imparting Jars thereto for normally moving the motor in two directions relative to the support, of a mechanism for controlling the direction of movement of the motor including a rack and a gear meshing with the rack-for rotation relative thereto in two directions due to the jars ot the motor, and a member rotatable .ina-single direction connectable with said gear for selectively controlling the direction of rotation of the latter.

ment in either directionincluding a iluid actuated nonreversible motor selectively connectable with said rotatable element for imparting rotation thereto in either direction, eilecting'thcreby the forward or backward `feeding movement o! the motor.

JOHN C. CURTIS.

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