US2913225A

US2913225A - Rock drilling apparatus

Info

Publication number: US2913225A
Application number: US624128A
Authority: US
Inventors: Norman E Wolfram
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-11-23
Filing date: 1956-11-23
Publication date: 1959-11-17
Anticipated expiration: 1976-11-17

Description

N. E. WOLFRAM aocx DRILLINGYAPPARATUS Nov. 17, 1959 2 Sheets-Sheet 1 filed Nov. 25, 1956 INVENTOR. NORMAN 5:. WQLFRAM ATTORNEYS Nov. 17, 1959 N. E. WOLFRAM 2,913,225

ROCK DRILLING APPARATUS Filed Nov. 2a, 1955 2 Sheets-Sheet 2 a? 6/ FIC3.5.'

55 I 29, 3a 3a 6 i L 8 5 E 536 3 1- g a 27 INVEN A NORMAN E. WOL AM I 43 44 BY Ul! 9 A oRNEYs United States Patent C) 2,913,225 ROCK DRILLING APPARATUS NormanE. Wolfram, South Deerfield, Mass. Application November 23, 1956, Serial No. 624,128: 4 Claims. (Cl. 255-49 This invention relates to drilling rigs and particularly to a rig for wagon drills and the like for drilling in'rock or other terrain and having a pneumatic drifter or rotatively and percussively driven hammer drill for actuating a rock drill bit.

An object of the invention is to provide a drilling device whereby low pressure air or exhaust air from a pneumatic drifter or pneumatic hammer drill will be utilized to assist in cleaning the drillings from a drilled hole hehind the bit.

Another object of the invention is to provide structure which will convey high pressure air through a drifter or drill to the front of a bit without appreciable loss in pressure to clean the bit and the hole being drilled.

Still another object is to provide simple and efficient structure for continuously feeding high pressure air without pressure loss to the front of a bit and exhaust or low pressure air behind the bit during the operation of the drifter or pneumatic hammer drill for a cooperative continuous cleaning action of a drilled hole and the bit.

Further objects, advantages and features will be apparent from the following description and the accompanying drawings.

In the drawings,

Fig. 1 is a front view of a drilling rig constructed and arranged in accordance with the present invention and as mounted on a conventional wagon drill mast;

Fig. 2 is a longitudinal sectional view with parts broken away of the drill rig shown by Fig. 1;

Fig. 3 is an enlarged view of the bit with the lower end of the structure shown by Figs. 1 and 2 in section and indicating a hole being drilled;

Fig. 4 is an enlarged fragmentary view of the front head or chuck end of the drifter or hammer drill as shown in Fig. 1 with the drill casing and coupling shown in section and with the drill shaft removed;

Fig. 5 is a sectional view taken on line 55 of Fig. 2;

and

Fig. 6 is a sectional view taken on line 66 of Fig. 2.

In common types of pneumatic hammer drills or drifters for rock drilling high pressure air operates the power tool to deliver the desired percussive and rotary action to the drill shaft and bit. High pressure air is also conducted at the same time through a bore in the drill shaft to the face of the bit for blowing drillings from in front of the bit and to clean out the hole behind the bit. In normal deep drilling operations drillings frequently become piled up in a hole being drilled to the extent that the air pressure being delivered into the bottom part of the hole is insufiicient to remove all drillings by blowing them up and out through the top of the hole. When the operator notices a blocked condition arising, the drifter can be manipulated to shut off air pressure to the hammer mechanism and to by-pass such air into the bore of the drill shaft. Pressure in the shaft bore is thus supplemented while the drilling is interrupted. The increased air blast then lifts the drillings out of the hole and when clear, the drilling continues as before. In diverting air 2,913,225 Patented Nov. 17, 1959 2 pressure which normally operates the drifter piston hammer the exhaust line is also shut off. The exhaust line in such tools normally is open to the atmosphere and it is a feature of the present invention to utilize the pressure of the exhaust line in a manner to assist the cleaning of the hole being drilled and to prevent the need for periodically stopping the drilling.

raise and lower a pneumatic drifter or rock hammer drill 18 slidably mounted on the mast for manipulating the rig in the usual manner.,

The mechanism of the drifter or rock hammer drill 18 is 'rotatively and percussively driven by high pressure air from an air inlet conduit 19 which is connected with an air compressor (not shown). Drifter 18 has a composite housing 20 (Fig. 2) with a chuck 21 at its lower end and a high pressure air inlet opening 22 at the other end. The hose or conduit 19 is connected to the inlet opening 22. i

A piston hammer 23 is slidably mounted in the housing 20 between the two ends'of the housing, a front hammer bearing 24 being provided in the housing with a distance piece 25 interposed between thehousing inner Wall 26 and the bearing 24. A ratchet 27, rifle bar 28, rifle nut 29, chuck driver 30 and chuck driver nut 31 are provided to turn or rotate the chuck intermittently as the hammer reciprocates. A valve chest 32 with an automatic valve 33 feeds high pressure air from inlet opening 22 to the piston hammer to reciprocate it in the housing. An exhaust port or opening 34 is also provided in the housing.

The chuck 21 has an inner member 35 and an outer member 36. A drill shaft or drill steel piece in the form of a stub shaft 37 is removably mounted in the chuck. The shaft 37 has a pair of spaced lugs 38 which seat in longitudinal grooves at 39 in the outer member 36 of the chuck. Outer member 36 has a lower end opening with opposed lug keyways 40 (Fig. 5) for initially inserting the lugs 38 in the chuck and for turning into longitudinal grooves 39 after the manner of a bayonet joint. In other words, grooves 39 are offset from and connected with the keyways 40. Thus once the lugs have been inserted through the keyways, shaft 37 can be turned to position the lugs for slidable movement in the grooves 39. Keeper blocks 41 extending to the upper end of member 36 and retained by member 35 (Fig. 5) may also be seated in the longitudinal grooves 39 to block the keyways 40. The keeper blocks thus provide one of the guiding surfaces for the lugs 38 and lock them in the grooves 39 so that they can slide longitudinally on rebound of the shaft 37 from a piston hammer blow but cannot turn and come out the keyways 40 of the chuck. It may be noted a washer or disc may be held by the couplingmember 46 (which is attached to the chuck of the housing as will be later described,

Fig. 4) to support the lower ends of the keepers 41 to maintain them against sliding out of the keyways 40. The rotary and percussive action and principal elements of the drifter assembly are of known construction and I Couplings 42 provide means for drill shaft extensions to be added to shaft 37 and a bit 43 is mounted on the drill shaft by an outer coupling, the outer end of the shaft 37 beingthreaded and the drill shaft extensions having threaded ends. Bit 43 has a threaded shaft44 at its rear for connection by the outer coupling 42 to any drill shaft extension.

A drill casing 45 is connected to the housing 20 at its chuck end to encircle shaft 37 and any shaft extensions to a point closely adjacent bit 43. A coupling member 46 with a flange 47 (see Fig. 4) abuts the front head or chuck end 21 of the housing, the flange having tie rod openings 48 to receive tie rods 49 extending through the openings. Rods 49 are secured at their inner threaded ends to tie rod nuts ,50 which secure a conventional pair of casing tie rodsSl to the housing. Nuts 52 clamp tie rods 49 to flange 47 and secure the coupling member 46 in position.

Coupling .46 also has an elbow conduit 53 for low pressure. air connected as shown by Fig. 1 by a tube 54 to an elbow conduit 55 leading to the: exhaust port 34 of the housing. The elbow conduit 55 is received in the chamber of an exhaust valve housing 55' of the drifter. This chamber, as will be understood by those skilled in the art, normally contains a valve for closing off the exhaust when by-passing high pressure air into the bore of the drill shaft. The elbow 55 has a constantly open port for exhaust as shown at 34' in Fig. 1. Thus exhaust air from the drifter operation will be conducted through the annular space around the drill shaft 37 and out of the casing 45 behind the bit 43. This, as will be seen, is to provide air to supplement high pressure air and assist in cleaning a drilled hole during the drilling. The drill casing 45 is tightly fitted to the coupling member 46 by a threaded connection (Fig. 4) with an abutment 56. The casing is concentrically spaced from the shaft extensions as by a spacer member 57 (Figs. 2 and 3) slidably fitting over the drill shaft and having annularly spaced wings or flanges 58 in slidable contact with the interior wall of the drill casing.

The low pressure exhaust air coming from the casing 45 supplements and cooperates with high pressure air supplied from the high pressure inlet opening 22 of the housing 20 through the housing, the drill shaft and bit, and without pressure drop or loss to the front of the bit so as to remove drillings and clear a drilled hole dun'ng drilling. Housing 20 has a central axial opening 60 (Fig. 2) at its rear end in which a high pressure air tube spud 61 is mounted. The axial opening is connected through rifle bar 28 and piston hammer 23,

which have like axial openings, all aligned for an air tube 64 to extend from the spud through the rifle bar and piston hammer into the chuck. Drill shaft 37 and bit 43' likewise have

axial openings

65 and 66 and the outer end of air tube 64 is slidably fitted in an enlarged axial opening 62 at the inner end of the shaft 37.

A conduit or tube 67 connects the air tube spud 61 with the high pressure inlet opening'22 of the housing. In this manner, high pressure air at the same pressure used in driving the hammer is directed continuously and without pressure loss to the front end of the bit. Axial opening 66 of the bit is forked at its front end to direct the high pressure air to each side of the tip at the leading face of the bit.

No appreciable loss or drop in pressure occurs between the air tube and the drill shaft since the air tube 64 extends slidably within the axial opening of the drill shaft and remains in such opening during all operative phases of the drifter or drill, both when the hammer is driving the drill shaft and when the drill shaft rebounds.

High pressure air is thus conducted from the inlet opening of the drifter through to the front of the bit. At the same time, exhaust air which otherwise would be vented to the atmosphere and wasted is conducted down into and through the sleeved drill casing 45 to the rear of the bit to assist in cleaning out the drilled hole. Thus material in the hole blown upwardly from the face of the bit by the high pressure airv is assisted upwardly and out the top of the hole by the exhaust air from the casing. Because there is no appreciable pressure loss in conveying the high pressure air to the front of the bit, the exhaust or casing air delivered behind the bit is always of lower pressure than the air expelled from the bit and cooperates with it rather than working against it in cleaning the bit and clearing the drilled hole. The holebeing drilled may. thus be kept continuously cleared of drillings and without interruption of the hammering action.

What is claimed is:

l. Rock drilling apparatus comprising a fluid operated percussive motor having an inlet connection with a source of high pressure fluid and an exhaust port, a drill bit mounted to transmit the percussive force of the motor tome 'face of a rock, passageway means leading from said inlet port to the forward end of said drill bit whereby high pressure fluid will be directed therefrom and passageway means leading from said exhaust port to a point adjacent the rear of said drill bit.

2. Rock drilling apparatus as in claim 1 wherein the inlet connection is to a source of pressurized air.

3. Rock drilling apparatus comprising an air driven percussive motor having a casing and a reciprocable piston mounted therein, a drill steel mounted in said casingto receive the force of said piston, a drill bit mounted at the outer end of said steel, said percussive motor having an air inlet connected to a source of pressurized air and an exhaust port, said drill bit having passageways opening on its forward end and passageway means interconnecting the drill bit passageways with said air inlet connection to the source of pressurized air, a tube securedto said casing and surrounding said steel in spaced relation, said tube terminatingjust short of said drill bit to provide an opening thereat, and a passageway means interconnecting said exhaust port and said tube whereby low pressure air is discharged adjacent the rear of said drill bit;

4. Rock drilling apparatus as in claim 3 wherein said passageway means connected with said air inlet comprises a relatively fixed tube centrally disposed in said piston and received by an opening therein, said drillsteel having a bore slidably and rotatively receiving the outer end of said fixed tube and communicating with said drill bit passageways and further wherein means are provided for rotating the drill steel during percussive operation of said motor.

References Cited inthe file of this patent UNITED STATES PATENTS 651,487 Leyner June 12, 1900 823,980 Walker June 19, 1906 2,646,967 Buccanero July 28, 1953 FOREIGN PATENTS 328,629 Great Britain Apr. 30, 1930-