US2347499A - Rock drill - Google Patents

Description

I z I 2 Sheets-Sheet 1 C. F. OSGOODl Rocx DRILL Filed Aug. 12, 1941 April 25, 1944.`

April 25, 1944. c, sGooD 2,347,49 9

ROCK'DRILL Filed Aug. 12, 1941 2 Sheets-Sheet 2 V' A 'IA ZQMA-W.

Patented Apr. 25, 1944 ROCK DRI-LL Charles F. Osgood, Claremont, N. H., assignor to Sullivan Machinery Company,a .corporation of Massachusetts Application August 12, 1941, Serial No. 406,513

6 Claims.

This invention relates to ro-ck drills -and particularly, but not exclusively, has reference to improvements in the feeding mechanism of a hammer rock drill of the mounteddrifter type.

An object of the -present 'invention is to vprovide an improved rock ,drill. Another object is to provide an improved rock drill feeding mechanism. A further object is to -provide an improved feeding mechanism of the vibration Controlled or so-called jump feed type operated by a vibratory action set up within the drill hammer motor during operation of the drill. A still Vfurther object is to provide improved `drill feeding mechanism embo'dying a flexible feeding element and having novel means for maintaining the flexible feeding element under tension. 'Yet another object is to Vprovide improved means Vfor automatically .yieldingly -tensioning the flexible feeding element and novel means for automatically maintaining the flexible feeding element under tension. Another objectis .to provide an improved and extremely compact arrangement -of 'the control means :forthe feeding mechanism.

Yet another objectiis to provide animproved arrangement of the 'fiexible control element on the drill guide andanimproved arrangement of the control mechanism associated :with the flexible element, whereby compactness is obtained. A still further object lis 'to 'provide an .improved rock dri111having novel V'combinations .and arrangement-of parts. V'Other and further objects andtheir resultant advantages will -be apparent after -the invention becomes lbetter -understood from -an examination of the pecification and claims in connection with the accompanying drawings, in which one embodiment ofthe invention is illustrated.

In the drawings: I

Fig. 1 is a side elevational view of ahammer rock drill in which the illustrative embodiment of the invention is incorporated, parts being shown in longitudinal Vertical section to illustrate structural details.

Pig. 2 is an enlarged rear end elevational view of the rock drill .shown in Fig'. 1.

Fig. 3 is an enlarged detail view in longitudinal Vertical section taken substantially .on line 3-3 of Fig. 2.

Fig. 4 is an enlarged detail cross sectional view taken on line 4-4 of Fig. 1.

Fig. 5 is a cross sectional view takencn line '5-5 of Fig. 3.

Fig. 6 is across sectional view-.taken-on-line V[-- of Fig. 3. i

Fig. 7 is 'a :detail sectional view taken on line .1-1 of 6.

Fig. .'8 is Va detail sectional view Vtaken on line `hFig. 9 .is va detail sectional view taken on line In the villustrative .embodiment of the invention the improved feedingr means generally designated I isembodied in a hammer rock drill'of the mounted zdrifter type .generally designated 2.

'It will vbe evident, however, that the invention ymay be .em-bod-ied in a-pparatus .of various other vin common transverse planes. The guide vShell has a usual bottom swivel plate 5 adapted for reception in the saddle mo'unting of a conventional .rock d-rillsupport. The drill hammer motor -3 includes ,afmotorcylinder .having a cylinder bore containing a reciproc'able hammer piston 'l adapted to deliver impact blows .to the shank 8 of a usual rock drillsteel 9. The drll steel shank is mounted in a usual manner within a chuck carried within a front chuck housing IO Asuitaloly secured to the motor cylinder, and the motor cylinder Ihas a back head II carrying ausual throttle'valve mechanism |2 for controlling the supply of motive fluid to the'motor cylinder. A usual fiuid distributing Valve mechanismisprovided for distributing themotive fluid to the opposite'ends of .themotor cylinder to effect-reciprocation of the hammer piston in a well-known manner. The .hammer'piston as it reciprocates inthe motor cylinder to effect the percussive actuation of the drill steel, imparts longitudinal vibrations .in .opposite directions to the nammermotor v3, ,and these longitudinal vibrations are employedvto effect feeding of the hammer motorbackand forth of the shell guide- .ways as .willlaterjbe described. i

The improved feedingV means l-includes a fiexible feed-controlchain which lies on .the-botvtom of .the.rguide .-.shell and extends longitudinally within .the I'guide .shell intermediate [the shell .guideways,..and .the .shell bottom preferably has an upstanding ledgelikeprojection 14 extending .centrally ,'longitudinally ,of the shell vand Vwith .which the'chain engages, for guid-ing the chain to maintainzthe latter in vparallelism with the shelLguideways. `As illustrated, the front end of the feed .cha'inis detachably secured at |5 .to .the front-.end ofv the guide s'hll .and is yieldingly connected at its rear end to an improved automatic Chain tensiom'ng device generally designated 16, attached to the rear end of the guide shell. A feed control sprocket |1 lies vvithin the guide shell 'midway between the guideways thereof as shown in Fig. 5, and this sprocket is keyed to a transverse shaft |8 arranged within the shell and journaled in suitable bearings supported within a casing |9 suitably attached to the rear head ll of the drill hammer motor 3. The axis of rotation of the sprocket |1 is parallel to the transverse planes in which the V shell guideways lie. Guide rolls 23 also journaled on transverse axes within the casing 19, are arranged at opposite sides of the feed sprocket I 1 for guiding the feed chain 3 with respect thereto. Integral with the feed sprocket |1 is a sprocket 2| connected by'an endless drive chain 22, extending upwardly between the shell guideways, to a sprocket 23 of a control mechanism generally designated 24, to be later described. The axis of rotation of the sprocket l1 is located below the top of the guide shell while the axis of rotation of the sprocket 23 is located a substantial distance above the top of the shell, in the manner shown in Figs. and 6.

Now again referring to the improved automatic chain tensioning device IB, it will be noted that the rear end of the feed chain |3 is attached at 25 to a bolt 25 slidably guided in a i' bore 21 of a casing 28 which is shown as arranged with its center line in alinement with a line which is midway between the sides `of the guide shell. This casing has lateral lugs 29 secured by bolts 30 to the rear end of the guide shell. Threaded on the rear end of the bolt 26 is an adjusting nut 3| and interposed between this nut and a shoulder 32 on a casing 28 is a coil spring 33. The coil spring 33 surrounds the bolt 26 and is arranged in a chamber 34 in the casing 28, and access to this chamber is attained by means of a detachable cover plate 35. Formed on the bolt 26 is a series of ratchet teeth 36 with which a spring-pressed pawl 31 engages, this pawl being arranged Within a Vertical bore 38 provided with a bottom closure plug 39. The pawl 31 is preferably of polygonal cross section so as to prevent rotation thereof within its bore. A coil spring 40 interposed between the plug and the pawl constantly urges the latter into engagement With the ratchet teeth. The coil spring 33 efiects tensioning of the. feed chain 13 and the pawl engaging the ratchet teeth maintains the feed chain under tension. If desired, the automatic tensioning device 13 may be arranged at the front end of the guide shell instead of at the rear end as disclosed, although this latter arrangement is preferred herein.

The control mechanism 24 is mounted on the casing 19 attached at the rear end of the hammer motor and is arranged above the top of the guide shell. This control mechanism includes a ratchet ring rotatably mounted. in a transverse bore 46 in the casing |9 and having internal ratchet teeth 41. This ratchet ring has its hub keyed to a control shaft 48 to which the control sprocket 23 is secured. This control shaft is suitably journaled within the casing |9, as shown in Fig. 6. A stationary pawl carrier 49 is arranged within the ratchet ring and is formed integral with a stub shaft 50 keyed to a cover plate 5| attached to the casing-VV -The pawl carrier carries' sets of reversible, spring-pressed pawls 52 and 53 engageable with the ratchet teeth 51 of the ratchet ring for controlling the direction of rotation of the feed sprocket ll. For selectively rendering the set of pawls en'ective, a shifter annulus 54 is rotatably mounted in the casing bore 48, and has recesses '55 to permit the pawls to move into engagement with the ratchet teeth. An internal cylindric surface 56 on the shifter annulus 54 is engageable with the pawls for pressing the latter inwardly into their released position out of engagement with the ratchet teeth. For moving the shifter annulus into its different positions, a lever 51 projects within a slot 58 in the annulus and this lever is secured to a control shaft 59 rotatably mounted in the casing cover plate 5|, and having a conveniently locatedv Operating handle 63. Spring-pressed plungers 6| and G2 arranged within suitably located bores in the casing cover plate are engageablev with notches respectively for looking the parts in their different adjusted positions.

The mode of operation of the improved rock drill is as follows: The drill guide shell 4 may be set up at the working face by clamping the swivel plate 5 within the saddle mounting of the rock drill support. The operator may then manipulate the throttle valve mechanism |2 to effect a supply of motive fluid to the drill hammer motor 3 to actuate percussively the drill steel 9. When the dril1 hammer motor is running toeffect percussive actuation of the drill steel, reciprocatory movement of the hammer piston 1 causes,` due to the sudden reversals in the directions of movements of the piston, vibratory or recoil movements of the hammer motor alternately in opposite directions longitudinally thereof, as is well understood by those skilled in the artresulting lin alternating tendencies to movement of the hammer motor forwardly and rearwardly with respect to the guide shell. Movement of the hammer motor in the feeding direction is permitted by the ratchet and pawl mechanism, the ratchet teeth at that time slipping freely over the pawls 53 to permit rotation with the feed sprocket |1 with respect to the feed chain |3, and movement of the hammer motor in the reverse direction is checked automatically by the ratchet and pawl mechanism, the then active pawls 53 engaging the ratchet teeth, holding the ratchet ring against rotation and thereby automatically checking reverse movement of the hammer motor. It is accordingly evident that with the parts as shown the control mechanism 24 associated with the feed chain |3 and feed sprocket |1 permits intermlttent step by step movement of the drill hammer motor in the feeding direction along the shell guideways While preventing movement of the dril1 hammer motor in the reverse direction. When the shifter annulus 54 is in the position shown in Fig. 8, the feed sprocket l1 is free to rotate in a counterclockwise direction as Viewed fin Fig. 3, relative to the feed control chain |3,

thereby permitting forward feeding movement of the drill hammer motor along the shell guideways, the relatively stationary control chain, as the hammer motorrmoves forwardly, effecting such counterclockwise rotation of. the feed sprocket. The reverse rotation of the feed sprocket |1 is checked automatically by the pawls 53 engaging the teeth of the ratchet ring 45, and as a result, rotation of the feed sprocket in a clockwise direction as viewed in Fig. 3 is prevented. It will thus be seen as the hammer piston 1 of the hammer motor reciprocates within the hammer motor cylinder to actuate percussively the drill steel, the jars imparted by the piston dueto the .sudden reversal in the direction of movement thereof cause the hammer motor to jump step by step in a forward direction along the shell guideways, thereby feeding the drill steel toward the Work. When the operator manipulates the handle 6B, the shifter annulus v513 may be rotated to effect release of the set of pawls 53 shown in Fig. 7 and to permit the set of pawls 52 to move into engagement with the teeth of the ratchet ring 45. When the parts are in this reversed position, the feed sprocket IT, as viewed in Fig. 3 is free to rotate in a clockwise direction, so that as the hammer piston rapidly reciprocates within the motor cylinder, the feed sprocket il is free to rotate in a reverse direction relative to the feed chain, due to the jars set up by the hammer piston, the then active pawls 52 releasing automatically to permit free rotation of the feed sprocket in the reverse feeding direction, and holding automatically the feed sprocket against rotation in the opposite direction. When the shifter annulus d is moved into its intermediate position, both sets of pawls 52 and 53 are free to engage the ratchet teeth; and as a result, the ratchet ring together with the feed sprocket are locked against rotation in both directions, so that movement of the hammer motor along the guide shell is prevented. During the feeding operation the coil spring 33 automatically efiects tensioning of the feed control chain i3 and the pawl 31 engaging the ratchet teeth 35 automatically maintains the feed chain under tension.

In lieu of the tension-maintaining ratchet disclosed, any suitable form of gripping means might be employed such as a friction cone or other frictional gripping means, and instead of the single pawl shown, any desired number of pawls may be used. Also, other means than that disclosed might be used to effect tensioning of the feed control chain such as pneumatic means, for instance of the kind embodying a fluid actuated piston contained in a cylinder. Further, intermeshing gearing or other forms of transmission means might be used instead of the endless drive chain between the two control shafts, and in place of the feed sprocket and feed control chain connections, a pulley and wire rope or cable might be used to equal advantage.

As a result of this invention, it will be noted that an irnproved rcck drill feeding meohanism is provided, having novel arrangements of parts whereby the rock drill is rendered extremely compact and rugged in design. It will further be evident that by the provision of the automatic tensioning device associated with the control chain, the latter is always maintained under the proper tension thereby preventing the possibility of a too-loose chain and as a result, increasing the eficiency of the feed mechanism. By the provision of the tensioning spring and the associated automatic ratchet device, the feed control chain is always properly tensioned and the tension of the chain is automatically maintained. Other advantages of the invention will be clearly apparent to those skilled in the art.

While there is in this application specfically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. -In a rock drill, the combination com-prising 'a 'guide lproviding parallel guideways lying in commontransverse planes, a drill hammer-motor guided on said guide for movement along the guideways thereof, a flexible control element 'at- 'tac'h'ed to said guide and extending along the 'bottom of vsaid guide longitudinally between said 'guideways, a rotary control member carried nby said 'hammer motor and arranged with its axis of rotation lying in a transverse plane in paral- 'lelism to the planes of said guideways, said control member engaging said flexible control element, 'a direction 'controlling device carried by said hammer motor above the guide guideways, and operative connections extending between theV guide guideways, for connecting said control Vdevice to said rotary control member.

2. 'In 'a rock drill, the combination 'comprising a Vguide providing parallel guideways lying in common transverse planes, a `drill hammer motor guided'on said guide for movement along the "guideways thereof, a flexible control 'element attached to said guide and extending along 'the bottom of said guide longitudinally midway between said guideways below the plane of the latter, a rotary control member carried by said hammer motor and engaging said flexible control element, a second rotary control member carried by the drill hammer motor and arranged in planes above the guide guideways, a direction controlling device associated with said second rotary control member, and an endless drive chain extending between the guide guideways for connecting said rotary control members in driving relation.

3. In a rock drill, the combination comprising a guide providing parallel guideways lying in common transverse planes, a drill hammer motor guided on said guide for movement along the guideways thereof, means for feeding said motor along said guide guideways including a flexible feed control element extending along the bottom of said guide longitudinally between the guideways thereof, a rotary control member journaled on said hammer motor on a transverse axis below the top of said guide, said axis of rotation of said control member being disposed parallel to the planes of said guideways, a second rotary control member journaled on said hammer motor on a parallel axis above the top of said guide, and operative driving connections between said rotary control members, said connections extending within said guide between the guideways thereof.

4. In a rock drill, the combination comprising a guide providing parallel guideways, a drill steel actuator movable along the guideways of said guide, a flexible feeding element extending longitudinally along the bottom of said guide midway between the guideways thereof, a rotary control member carried by said drill steel actuator and arranged within said guide between the guideways thereof, said rotary member engaging said flexible element, a control mechanism carried by said actuator and arranged outside of said guide, and operative connections between said control mechanism and said rotary member, said connections extending into said guide between the guideways thereof at one side of said rotary member.

5. In a rock drill, the combination comprising a guide providing parallel longitudinal guideways disposed in common transverse planes, a hammer motor guided on said guide for movement along said guideways and having jars imparted thereto during the operation thereof, and means operated by said jars for feeding said hammer motor step by step along said guide, said feeding means including a flexible feed control element arranged longitudinally of said guide mid- Way between the sides thereof, a rotary control member engaging said flexible control element and arranged with its aXis of rotation parallel to the planes of said guideways, a control mechanism for controlling the direction of rotation of said rotary member, resilient means for automatically tensioning said flexible element including a tensioning element arranged longitudinally midway between the sides of said guide at one end thereof and guided for longitudinal movement relative to said guide, and an automatic grip device associated with said longitudinally movable tensioning element for permitting free movement of the latter longitudinally in a direction to tighten said exible element while precluding movement in the opposite direction thereby automatically to maintain said flexible element under tension.

6. In a rock drill, the combination comprising a guide providing spaced apart parallel longitudinally extending guideways, a drill hammer motor guided on said guide for movement along said guideways, a flexible control element attached to said guide and extending within said guide longitudinally along the bottom thereof midway between said guideways, a rotary control member carried by said hammer motor and engaging said flexible element, a direction controlling device carried by said hammer motor externally of said guide, said control member and said controlling device being arranged on parallel transverse axes arranged parallel to the planes of said guide guideways, and operative transmission connections between said rotary control member and said controlling device, said connections extending from the exterior of said guide through the space between said guideways into said guide.

CHARLES F. OSGOOD.

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