US3467207A

US3467207A - Universal drilling machine

Info

Publication number: US3467207A
Application number: US585373A
Authority: US
Inventors: Harley G Pyles; Charles D Albright; Robert E Haun
Original assignee: Individual
Current assignee: CHARLES D ALBRIGHT; ROBERT E HAUN; Envirotech Corp
Priority date: 1966-10-10
Filing date: 1966-10-10
Publication date: 1969-09-16
Anticipated expiration: 1986-09-16

Description

Sept. 16, 1969 H. PYLES ET UNIVERSAL DRILLING MACHINE Filed Oct. 10, 1966 5 Sheets-Sheet 1 INVENTORS HARLEY G.Pfll CHARLES D.ALBRIGHT ROBERT E.HAUN

Sept. 16, 1969 H. e. PYLES ET UNIVERSAL DRILLING MACHINE 5 Sheets5heet 1;

Filed Oct. 10, 1966 I N VE NTORS HARLEY G. PYLES p 1969 H. G. PYLES ET AL 3,467,207

' UNIVERSAL DRILLING MACHINE Filed Oct. 10. 1966 5 Sheets-Sheet 5 5 n [H in "MI I IJ II I 3; HARL 5. PYLES ca-lAmEs ALBRIGHT BY ROBERT E. HAUN 534L277? K aw: M

Sept. 16, 1969 H. G. PYLES ET AL 3,467,207

UNIVERSAL DRILLING MACHINE Filed Oct. 10, 1966 5 Sheets-Sheet 4 1 I J ll 5* UH INVENTORS HARLEY G. PYLES CHARLES D. ALBRIGHT BY ROBERT E. HAUN Sept 16, 1969 PYLES ET AL 3,467,207

UNIVERSAL DRILLING MACHINE Filed Oct. 10, 1966 5 Sheets-Sheet 5 cu an N h N N g 93 3 m N N :1 mm m 8 03 If) N /g N \g; 55 Q l O In g E N INVENTORS N HARLEY e. PYLES odARLes 0. ALBRIGHT y ROBERT E. 'HAUN 5 d 4 United States Patent 3,467,207 UNIVERSAL DRILLING MACHINE Harley G. Pyles, 109 Gaston Ave., and {Charles D. Al-

bright, 506 West End Drive, both of Falrmont, W. Va. 26554, and Robert E. Haun, 4827 Millbrooke Road, Albany, Ga. 31701 Filed Oct. 10, 1066, Ser. No. 585,373 Int. Cl. E21c 3/02, 19/00; EZlb 7/00 US. Cl. 175-55 10 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a drilling machine that includes thrust means for imparting thrust forces to the drilling implement and rotary drive means to impart high speed rotary motion to the same drilling implement. A power operated means is provided for advancing the drilling implement longitudinally on a support member during the drilling operation. A shock absorbing means is connected to the drilling implement advancing member to absorb the thrust forces exerted in a direction opposite to the direction of advance of the drilling implement. There are also provided means to vary the frequency of the thrust forces imparted by the thrust means.

This invention relates to a universal rotary percussion drilling machine and more particularly to a universal drilling machine that selectively imparts longitudinal percussive motion, high speed rotary motion, or both, to the drilling implement as it penetrates the material.

In the mining of various materials, particularly the harder ores, it is the present practice to dislodge the material from the face with explosives. A series of spaced holes are drilled into the face at varying angles to receive the explosives. The holes are charged with an explosive, properly stemmed and sequentially detonated to dislodge the material from the face.

The number of holes drilled in the face depends on many factors, such as the hardness of the material, the desired size consist of the dislodged material and the type of explosives used. It is apparent, because of the large number of holes that must be drilled in the face to properly dislodge the material, the productivity and cost of mining is dependent largely on the speed at which the holes can be drilled into the material.

The ore or material being mined is not homogeneous and the hardness of the material will vary substantially within the same seam. It has been discovered, to obtain optimum penetration in materials of different hardness, that a combination of rotary and precussive forces must be applied to the drilling implement As the hardness of the material increases, the speed of rotation of the drilling implement is decreased and the percussive forces are increased. Conversely, when the material being drilled decreases in hardness, the rotation of the drilling implement is increased and the percussive forces are decreased. Because of the variations in hardness in the seam, the optimum combination of rotary and percussive forces is usually determined by the operator during the drilling operation. To have a drilling machine that is capable of maintaining optimum penetration rates in strata of dilferent hardness, it is essential to be able to vary the torque, thrust, speed of rotation, percussion frequency and percussion force exerted on the drill bit. We

3,467,207 Patented Sept. 16, 1969 have provided a drilling machine that is capable of changing all of these forces.

It has also been discovered where a combination of rotary and percussive forces is exerted on the drilling implement that the rate of penetration is increased when the reverse thrust exerted by the percussion unit is opposed by a thrust that exceeds the percussive thrust. A continued advancing thrust is then maintained on the drilling implement as it penetrates the material. It has also been discovered where an extensible support means is provided for the drilling implement that, the wear on the guides and the friction losses are minimized when the twisting or cocking moments exerted on the drill head and other support members are eliminated as the various components move relative to each other during advance of the drilling implement.

Briefly, the invention is directed to an extensible drillin machine having both rotary and percussive drive means in the drill head. Means are provided to vary the thrust force and frequency of the percussive means and to vary the linear thrust on the drilling implement and the speed of rotation of the rotary drive means. There is also provided a means for absorbing the reverse thrust exerted by the percussive means to thereby maintain a continued advancing thrust on the drilling implement. The power operated means for advancing the drill head is located in the same plane as the drilling implement to counteract the reactive thrust exerted by the drilling implement and minimize the twisting moments exerted on the drill head.

Accordingly, the principal object of this invention is to provide a drilling implement having means to impart both rotary motion and percussive thrusts to the drilling implement.

Another object of this invention is to provide a drilling implement having means to impart rotary motion and percussive thrusts to the drilling implement and vary the effective forces exerted by the rotary and percussive devices.

Another object of this invention is to provide a means to absorb the linear thrust exerted by a percussion unit on a drilling machine in a direction opposite to the direction of drilling in the material.

Another object of this invention is to provide an extensible drilling implement support wherein the twisting moments on the various components during the drilling operation to thereby minimize the friction and wear on the sliding portions of the various components.

These and other objects and advantages of this invention will be more completely disclosed and described in the following specification, the accompanying drawings and the appended claims.

In the drawings:

FIGURE 1 is a view in side elevation of a mobile drilling machine having an extensible drill assembly with a rotary percussive drill head mounted thereon.

FIGURE 2 is a top plan view of the extensible drill assembly illustrated in FIGURE 1.

FIGURE 3 is a front end view of the drill assembly of FIGURE 2.

FIGURE 4 is a top plan view of the drill assembly illustrated in FIGURE 2 with the drilling implement removed.

FIGURE 5 is a view in side elevation of the drill assembly illustrated in FIGURE 4 in an extended position.

FIGURE 6 is a view similar to FIGURE 5 illustrating the drill assembly in a telescoped position with the drill head advanced toward the front portion of the feed rack.

FIGURE 7 is 'a view in section taken along the lines 3 77 in FIGURE illustrating the construction of the feed rack.

FIGURE 8 is a view in section taken along the lines 88 in FIGURE 5 illustrating the construction of the drill carriage and the manner in which the drill carriage is telescopically supported on the feed rack.

FIGURE 9 is a view in section taken along the lines 99. in FIGURE 5 illustrating the manner in which the drill head is movably supported on the drill carriage.

FIGURE 10 is a view in section taken along the lines 10--10 in FIGURE 5 illustrating the reverse thrustabsorbing mechanism.

FIGURE 11 is a view in side elevation of one embodiment of the drill head illustrating the eccentric weights operable to impart linear thrusts of equal force in opposite directions along the longitudinal axis of the drilling implement.

FIGURE 12 is a top plan view of the drill head with the cover removed to illustrate the shafts and drive gearing for the eccentric weights and the device gearing to impart rotary motion to the drilling implement.

FIGURE 13 is similar to FIGURE 11 and illustrates a drill head in side elevation with a plurality of eccentric weights secured to rotatable shafts supported in the drill head. The eccentric weights in FIGURE 13 are arranged to impart differential thrusts to the drill head 13.

FIGURE 14 is a view similar to FIGURE 12 and illustrates the gearing for rotating the shafts and eccentric weights and for rotating the drilling implement.

FIGURE 15 is a schematic hydraulic diagram of suitable apparatus to vary the forces on the drilling implement.

Referring to the drawings and particularly FIGURES 1-5, there is illustrated a mobile drilling machine generally designated by the numeral 10, The mobile drilling machine has a body portion 12 supported on propelling wheels 14 and 16. A boom member 18 is pivotally secured to the front end of the body portion 12 and has a drill assembly 20 connected thereto. The boom 18 is arranged to pivot in a horizontal plane and also in a vertical plane to position the drill assembly 20 at various locations relative to the mine face. On the front end of the boom 18 there is a pivot mechanism 22 that permits the drill assembly 20 to rotate about a vertical pivot axis. The pivot mechanism 22 has a feed rack support means 24 pivotally secured thereto to pivot the drill assembly 20 in a vertical plane about a pivot pin 26. An extensible hydraulically operated member 28 is connected to the pivot mechanism 22 and feed rack support means 24 and is arranged to pivot the drill assembly 20 about the pivot pin 26 and maintain the drill assembly in a preselected angular relation. It will be apparent that the mobile drilling machine 10 with the boom member 18 may position the drill assembly 20 in any desired position for horizontal and angular drilling. The drill assembly 20 may be utilized with other types of support means for drilling in other positions without departing from the scope of this invention.

A suitable source of hydraulic fluid under pressure is provided in the body portion 12 for the hereinafter described power actuating means. Manually operated control valves 30 are positioned on the body 12 and are arranged to vary the pressures to the hydraulically actuated telescopic means and to the hydraulically operated motors on the drilling implement. The schematic hydraulic diagram in FIGURE 15 illustrates a suitable manner in which hydraulic fluid under pressure is supplied to the various cylinders and hydraulic motors. The supply and return hoses to the hydraulically actuated devices are not shown in drawings 1-14 so that the structural details of the drill assembly 20 may be shown. It should be understood, however, that flexible hoses or other suitable means are arranged to convey the hydraulic fluid under pressure to the various hydraulically actuated devices.

Referring to FIGURES 2-10, the drill assembly generally designated by the numeral 20 has a feed rack generally designated by the numeral 32 movably secured to the feed rack support means 24. A drill carriage generally designated by the numeral 34 is supported on the feed rack 32 and is movable longitudinally relative thereto. A drill head generally designated by the numeral 36 is supported on the drill carriage 34 and moves longitudinally thereon. A drilling implement 38 is secured to the drill head 36 and extends forwardly therefrom and has a drill bit 40 on the front edge thereof that penetrates the material during the drilling operation. With this arrangement the drill assembly 20 is extensible in that the drill carriage 34 moves relative to the feed rack 32 and the drill head 36 moves longitudinally relative to drill carriage 34. The drilling implement 38 which is connected to the drill carriage 34 is of a length substantially equal to the length of the feed rack 32 and drill carriage 34 so that substantially the entire length of the drilling implement 38 penetrates the material being drilled when the drill assembly 20 is in a telescoped position, as illustrated in FIGURE 6. This extensibility of the drill assembly 20 provides for the drilling of relatively deep holes in the material.

Referring in greater detail to the construction of the elements of the drill assembly, the feed rack 32 has a pair of parallel spaced

channels

42 and 44 connected at their front end by a transverse plate 46 and at their rear end portions by a lower horizontal plate 48 (FIG. 7) to form a frame-like member. The feed rack 32 is connected to the feed rack support means 24 by brackets or guides 50 extending over the lower outwardly extending flanges of the

channels

42 and 44. A cylinder 52 is secured to the feed rack support means 24 and has a piston 54 extending forwardly therefrom. The piston 54 is connected to a bracket 56 depending downwardly from the feed rack 32. With this arrangement the feed rack 32 may be moved longitudinally on the feed rack support 24 so that the forwardly extending abutment 58 can be moved into abutting relation with the mine face to provide an additional support for the drill assembly 20 during the drilling operation. The transverse plate 46 connecting the

channels

42 and 44 at their front end portions has an aperture 60 therethrough with suitable bearings 62 within the aperture 60. The drilling implement 38 extends through the aperture 60 and is supported in the bearings 62.

The drill carriage 34 mounted on the feed rack 32 has a pair of parallel spaced side members 64 and 66 with outwardly extending top flanges 68 and 70 and intermediate flanges 72 and 74 (FIG. 8). The

flanges

72 and 74 ride on the upper surface of the top flanges of the

feed rack channels

42 and 44. Adjustable guides or

brackets

76 and 78 secure the drill carriage 34 to the feed rack 32. The drill carriage 34 has a transverse front plate 80 and a transverse rear plate 82 that maintain the side members 64 and 66 in spaced relation and form a frame-like drill carriage 34.

The transverse front plate 80 has an aperture 84 therethrough which is aligned with aperture 60 in the feed rack front plate 46. A bearing 86 is secured to the plate 80 and the drilling implement 38 extends through bearings 86 and '62 in the front plates 80 and 46 of the drill carriage and feed rack respectively. With this arrangement the drilling implement 38 is supported at two locations during the entire drilling operation. The arrangement of the drill carriage 34 on the feed rack 32 and the drill head 36 on drill carriage 34 permits the bearing 86 on the front of the drill carriage transverse plate 80 to remain at a location equidistant between the front of the drill head 36 and the front bearing 60 in the feed rack front plate 46. The drilling implement 38 thus has a support means, i.e. bearing 86, at an intermediate location between the drill head 36 and the front of the feed rack 32 during the entire drilling operation to thereby minimize the deflection of the drilling implement 38 as it advances during the drilling operation.

The feed rack side members 40 and 44 have

cylinders

88 and 90 secured at their rear end portions by

brackets

92 and 94.

Piston rods

96 and 98 extend from the front of the

respective cylinders

88 and 90 and are connected at their end portions to brackets 100 and 102 secured to the rear transverse plate 82 of the drill carriage 34. Within the

cylinders

88 and 90 there are pistons (not shown) secured to the ends of the

rods

96 and 98 so that hydraulic fluid supplied to opposite ends of the

cylinders

88 and 90 will exert a force on the piston and extend and retract the

respective piston rods

96 and 98 in a conventional manner. Since the

cylinders

88 and 90 are connected at their rear end portions to the feed rack 32 and the end portions of the

piston rods

96 and 98 are connected to the drill carriage 34, the extension or retraction of the

rods

96 and 98 Within cylinders 88 and 90- will move the drill carriage relative to the feed rack 32. For example, during the drilling operation the

piston rods

96 and 98 retract into the

cylinders

88 and 90 to advance the drill carriage 34 toward the front end of the feed rack 32 and thus, as will be later described in more detail, advance the drilling implement 38 into the mine face.

The drill head 36 is box-like in construction and is positioned between the feed rack side members 64 and 66. The drill head 36 has a top plate 104 (FIG. 9) that extends beyond the flanges 68 and 70 of the feed rack 32 and is slidably positioned thereon. Guides or brackets -6 and 107 secure the drill head 36 to the feed rack 32. With this arrangement, the drill head 36 is movable longitudinally on the drill carriage 34 to advance the drilling implement 38 connected to the front end thereof.

The drill carriage side menbers 64 and 66 each has a stub shaft 108 and 110 extending inwardly therefrom adjacent the front transverse member 80 (FIG. 4). Rollers 112 and 114 are rotatably mounted on stub shafts 108 and 110. The drill carriage 34 has a transverse shaft 116 secured to side members 64 and 66 adjacent the rear transverse plate 86 and a pair of

rollers

118 and 120 are rotatably mounted on the shaft 116. A drum 122 is positioned between the

rollers

118 and 120 and is arranged to support the flexible hoses (not shown) that supply hydraulic fluid to the drive motors associated with drill head 36. Although the

members

112, 114, 118 and 120 have been described as rollers, it should be understood that sprockets or other types of rotary supports may also be used.

The feed rack 32 has a pair of spaced depending brackets 124 on the plate 48 between the drill carriage side members 64 and 66, one of the depending brackets is shown in FIGURE 5. The drill head front wall 126 has a corresponding pair of spaced

brackets

128 and 130 extending forwardly therefrom on opposite sides of the drilling implement 38. A pair of paced

parallel chains

132 and 134 are connected at one end to the respective brackets 124 on feed rack 32 and have their other end connected to the

brackets

128 and 130 on the drill head front wall 126. The intermediate portions of

chains

132 and 134 are reeved about respective rollers 112 and 114. Reverse

thrust absorbing devices

136 and 138 form a part of the chain and are illustrated as connected to the

chains

132 and 134 adjacent the

brackets

128 and 130. The thrust absorbing devices are arranged to absorb the reverse thrust exerted by the percussive means, as will later be described in greater detail.

The drill head 36 is advanced on the drill head carriage 34 by means of the

flexible chains

132 and 134 as the drill head carriage 34 is advanced on the feed rack 32 when the

piston rods

96 and 98 are retracted into the

respective cylinders

88 and 90. It should be noted, as illustrated in FIGURE 5, the

chains

132 and 134 between the drill head front face 126 and rollers 112 and 114 are in the same horizontal plane as the longitudinal axis of drilling implement 38, indicated by the dash-dot line 140 in FIG- URES 5 and 6. With this arrangement the reactive thrust exerted by the drilling implement 38 on the drill head 36 is opposed by the advancing thrust exerted by the

chains

132 and 134 in the same plane so that twisting or cocking moments are not exerted on the drill head 36. The advancing thrust exerted by the

chains

132 and 134 is opposed by a reactive thrust through the drilling implement 38 caused by the opposition of the material being drilled. With other arrangements, where twisting moments are exerted in a drill head, the drill head cocks or twists in the drill carriage 34 so that the guides or brackets 106 and 108 are urged against the flanges of the drill carriage side members 64 and 66, and substantial friction must be overcome between the rubbing elements during the advancing of the drill head. This excessive friction causes rapid wear of the brackets and the other parts of the drill head 36. With the herein above described arrangement wherein the reactive thrust of the drilling implement is opposed by the

chains

132 and 134 in the same plane, the twisting moments on the drill head 36 are not present and the wear due to friction is eliminated and substantially all of the advancing thrust exerted by the

chains

132 and 134 is therefore transferred through the drill head 36 into the drilling implement 38.

The feed

rack side members

42 and 44 have other brackets 142 secured thereto and the drill head 36 has

brackets

144 and 146 extending rearwardly therefrom. A second pair of chains 148 and 150 are secured at their end portions to the

respective brackets

142 and 144 and are reeved about the

rear rollers

118 and 120. With this arrangement as the

rods

96 and 98 move outwardly from the

cylinders

88 and 90, the drill head 36 is retracted on the drill head carriage 34.

The reactive thrust of the drilling implement 38 is transferred to the

chains

132 and 134 and since the

chains

132 and 134 are reeved about the rollers 112 and 114, the reactive thrust of the chains is located at the midpoint between the upper section of the chain beneath the rollers.

This location is coincident with the longitudinal axis of stub shafts 108 and 110. The longitudinal axes of cylinders 88 and are thus in the same plane as the axes of the stub shafts 108 and are the reactive forces of

chains

132 and 134 are opposed by the

cylinders

88 and 90 along their longitudinal axes. Since the axes of the cylinders are in the same plane as the line of thrusts of

chains

132 and 134, twisting moments are not present between the drill carriage 34 and the feed rack 32 and excessive wear and frictional forces on the

guide members

76 and 78 is minimized.

The embodiment of the drill head 36 is illustrated in FIGURES 11 and 12 and has a housing 152 with four

shafts

154, 156, 158 and 160 rotatably supported therein in spaced parallel relation to each other. Semicircular eccentric weights 162 are detachably secured to the opposite ends of each of the shafts by brackets 164. The weights are arranged so that upon rotation they impart thrust forces to the drill head 36 in a direction parallel to the longitudinal axis of the drilling implement 38 so that linear thrust forces are imparted to the drilling implement. For example, in FIGURE 11, assuming the eccentric weights are rotating, all the weights 162 are exerting a thrust in a forward direction toward the front of the drill head 36 and in the direction of drill advance. Upon rotation through 90, because of the manner the shafts are geared to each other, pairs of weights oppose each other in vertical directions to cancel out thrusts in the vertical direction. Upon rotation through another 90, i.e. from that illustrated in FIGURE 11, the eccentric Weights exert a thrust in a direction opposite to that illustrated in FIGURE 11. The effective thrust force of the eccentric weights can be rapidly changed by substituting heavier or lighter eccentric weights on the ends of

shafts

154, 156, 158 and 160.

Referring to FIGURE 12, the drive means for rotating the eccentric weights as above described includes a hydraulic percussion drive motor 166 supported on the drill head housing rear wall 168. The motor 166 has a shaft 170 with a bevel gear 172 secured thereto. The bevel gear 172 meshes with a bevel gear 174 mounted on a shaft 176 suitably Supported by housing 152. A spur gear 178 is also secured to shaft 176 and meshes with spur gear 180, which is mounted on a suitably supported idler shaft 182. The idler shaft 182 has another spur gear 184 secured thereto that meshes with a spur gear 186 secured to shaft 160 adjacent one wall of the housing 152. With this arrangement rotation of shaft 170 by motor 166 is transmitted through the above described gear train to rotate shaft 160 on which a pair of eccentric weights 162 are mounted. Adjacent the other side of the housing 152 all of the

shafts

154, 156, 158 and 160 have spur gears 188 nonrotatably secured thereto and in meshing relation with each other. The spur gears 188 are indicated in dotted lines in FIGURE l1 and show the manner in which all four

shafts

154, 156, 158 and 160 are driven at the same speed. The frequency of the linear thrusts exerted by the eccentric weights 162 can be varied by varying the speed of motor 166. Thus, with the above described eccentric weight drive mechanism and the quickly detachable eccentric weights, it is possible to rapidly vary both the frequency and the thrust force exerted by the drill head on the drilling implement. It should be understood, however, that other gear arrangements are possible to rotate the

respective shafts

154, 156, 158 and 160 to rotate the eccentric weights in the proper directions at a preselected speed. In addition, the prime mover for rotating the shafts could be a variable speed electric motor or the like.

The drill head front wall 126 has an aperture 190 therethrough and a receiver 192 for the drilling implement 38. Suitable locking means are provided in the receiver 192 and also bearings for rotatably supporting the drilling implement 38. Connected to the receiver 192 in a shaft 194 that extends through the aperture 190 in the drill head front wall 126. The shaft 190 is secured to a portion of the receiver 192 to rotate the same upon rotation of shaft 194. The shaft 194 is suitably' supported in the drill head rear wall 168 and has a spur gear 196 nonrotatably secured thereto. A drilling implement rotating motor 198 is secured to the drill head rear wall 168 and has a shaft 200 extending into the drill head housing 152. A spur gear 202 is secured to the motor shaft 200 and meshes with a large spur gear 204 mounted on a shaft 206. The shaft, in turn, has a spur gear 208 mounted thereon that meshes with spur gear 206 secured to main shaft 194. Thus, upon rotation of drill rotating motor 198, the shaft 194 is rotated through the above described gear train to rotate the drilling implement 38. The rotational speed of the drilling implement 38 can be varied by varying the speed of rotary drive motor 198. With the above described drill head 36 it is now possible to selectively impart longitudinal percussive thrusts to the drilling implement 38 and/or rotary motion. The speed of rotation can be varied by varying the speed of motor 198 and the frequency of the linear thrusts can be varied by varying the speed of percussion motor 166. The thrust forces imparted by the drill head 36 can be changed by changing the effective weight of eccentric 162.

Referring to FIGURES l3 and 14, there is illustrated another embodiment of the drill head 36 wherein differential thrusts forces are imparted to the drilling implement 38 and rotary motion is imparted thereto by a drive similar to that illustrated in FIGURES 11 and 12. The elements in the drill head illustrated in FIGURES 13 and 14 that are the same as the elements in the drill head illustrated in FIGURES 11 and 12 will be designated by the same numerals. In order to provide a differential motion to the drill head 36 illustrated in FIGURES 13 and 14 an additional pair of

shafts

210 and 212 are rotatably supported in the drill head housing 152 in spaced parallel relation to each other and in spaced parallel relation to the

shafts

154, 156, 158 and 160. The shaft 210 is in the same plane as

shafts

154, and 156, and shaft 212 is in the same plane as

shafts

158 and 160. Eccentric weights 214 are secured to the ends of

shafts

210 and 212 by means of brackets 216 and have one-half the mass of the eccentric weights 162. The

shafts

210 and 212 are rotated at twice the speed as

shafts

154, 156 through the following gear train. Drive from motor 166 is transmitted through shaft to meshing

bevel gears

172 and 174. Secured to the other end of the shaft 176 is a spur gear 218 that meshes with an intermediate gear 220 rotatably positioned on shaft 212. The gears 218 and 220 are indicated in dotted lines in FIGURE 13. Intermediate gear 220, in turn, meshes with spur gear 186 secured to shaft 160 to thereby drive the four

shafts

154, 156, 158 and 160 through the meshing gears 188, as previously described. Also meshing with gear 218 is a reach gear 222 positioned on shaft 224. The spur gear 222 in turn meshes with a gear 226 formed on shaft 210'. The ratio of the

gears

222 and 226 is such that the shaft 210 rotates at twice the speed as

shafts

154, 156, 158 and 160. Shaft 210 has another spur gear 228 nonrotatably secured thereto that meshes with a similar gear secured to shaft 212 positioned therebelow so that

shafts

210 and 212 rotate in the opposite direction at twice the speed as

shafts

154, 156, 158 and 160.

The diflferential thrust is obtained with the drive mechanism illustrated in FIGURES 13 and 14 in the following manner. For example, in FIGURE 13, assuming the shafts are rotating, a forward thrust is imparted to the drill head 36 by the

eccentric weights

162 and 214 in the position illustrated. The thrust force of eccentric weights 214 is additive to the thrust forces of eccentric weights 162 in the position illustrated in FIGURE 13. The

shafts

210 and 212 are rotating at twice the speed of the

shafts

154, 156, and 158 and 160 so that the effective thrust of each of the weights 214 is the same as each of the weights 162.

When the weights 162 move through 90 from that illustrated in FIGURE 13, the eccentric weights 214 move through to impart a thrust toward the rear of the drill head 36 having a thrust force equal to the thrust force exerted by the weights 214. As the weights 162 progress another 90, the weights 162 impart a rearward thrust force on the drill head 36 and the eccentric weights 124 exert a forward thrust on the drill head 36 to cancel one-half of the rearward thrust imparted by the weight 162. As the weights 162 progress through another 90", the weights 214 have progressed 180 from that illustrated in FIGURE 13 to impart a rearward thrust to the drill head 36. When the eccentric weights 162 progress through another 90 of rotation, the weights 214 have progressed through 180 of rotation and the

weights

162 and 214 assume the position illustrated in FIGURE 13 to provide an additive forward thrust to the drilling implement equal to the effective thrust of all of the eccentric weights in the eccentric drive mechanism illustrated in FIGURES 13 and 14. With this arrangement it is possible to provide a differential thrust to the drilling implement 38 which, in a forward or drilling direction, is at a maximum and utilizes the thrust force of all of the eccentric weights. In the reverse direction, however, the smaller weights 214 cancel an equivalent portion of the thiust force exerted by the eccentric weights 162 to thereby reduce the rearward thrust exerted by the drive mechanism.

As will be now described, it is highly desirable to reduce as much as possible the rearward thrust exerted by the percussive units so that the drill bit remains in abutting relation with the base of the hole or bore, especially when rotary motion is being applied to the drilling implement 38.

As previously described, the

flexible chains

132 and 134 have reverse

thrust absorbing devices

136 and 138 secured thereto to absorb the reverse thrust of the previously described percussive mechanism. A suitable reverse thrust absorbing device is illustrated in FIGURE 10. 1t

should be understood, however, that other suitable thrust absorbing devices could be utilized to absorb the reverse thrust of the drill head 36. The thrust absorbing device has a housing 230 with a rearwardly extending bracket 232. The bracket 232 may be connected to the

brackets

128 or 130 on the drill head front wall 126. There is provided an aperture 234 in the front wall of the housing 230. A rod 236 extends through the aperture 234 and has a transversely flanged end portion 238 within the housing 230. The other end of the rod 236 is connected to the chain 132. Positioned between the front Wall of housing 230 and the transverse flange 238 on the rod 236 is a compression spring 240.

The reverse thrust absorbing device 136 functions in the following manner. As the drilling element 138 is being advanced into the mineface by means of retracting the

piston rods

96 and 98 in the

cylinders

88 and 90, a tension is exerted on the

chains

132 and 134. The tension on

chains

132 and 134 compresses the spring 240 within the housing 230. When a reverse percussive thrust is exerted by the drill head 36 the spring 240 is compressed further. A suflicient forward force is retained on the drilling implement 38 through the compressed spring 240 and the

chains

132 and 134 to maintain the drill bit in abutting relation with the base of the bore hole. Thus, the continued deflection of the spring 240 during the drilling operation, absorbs a substantial portion of the re verse thrust imparted by the percussive unit and maintains the drill bit in abutting relation with the base of the bore hole. It has been found where both rotary and percussive forces are used simultaneously during the drilling operation, optimum penetration is obtained when the drill bit is continuously maintained in abutting relation with the base or end of the bore hole and the reverse

thrust absorbing devices

136 and 138 provide a means to maintain the drill bit in abutting relation with the base of the bore hole during the reverse thrust imparted by the eccentric weights.

FIGURE 15 illustrates diagrammatically a suitable hydraulic system for the percussion motor 166, the rotary drive motor 198 and the

cylinders

88 and 90. FIGURE 15 is schematic and it should be understood that other types of hydraulic arrangements could be provided for the

mechanisms

166, 198 and 90. Further, electrical drive could be substituted for the various hydraulic motors and the piston-cylinder servomechanism.

FIGURE 15 illustrates a reservoir 242 for the hydraulic fluid. Schematically throughout FIGURE 15 where the fluid is returned to the reservoir 242, a return is indicated diagrammatically and also numbered 242 for convenience. There are three constant volume pumps 244, 246 and 248 having their intake opening connected to reservoir 242 by conduits 250, 252 and 254. A commondrive 256 is illustrated schematically to drive the constant volume pumps 244, 246 and 248 at a predetermined constant speed. A conduit 258 is connected at one end to pump 244 and at the other end to a valve 260. The valve 260 contains an integral pressure relief valve that by-passes hydraulic fluid above a preselected and preset pressure through outlet conduit 262 to reservoir 242. In the off position, the fluid supplied through conduit 258 flows through valve 260, out conduit 262 and returns to reservoir 242. There is a second outlet conduit 264 that connects valve 260 with the hydraulic motor 166 associated with the eccentric drive previously described. Thus, by handle 266 on valve 260 the operator can actuate percussion motor 166 to rotate at a preselected maximum speed. A branch conduit 268 is connected at one end to conduit 258 and is connected at the other end to an adjustable flow control valve 270. The adjustable flow control valve 270 may be adjusted by handle 274 to by-pass a constant volume of hydraulic fluid. The valve 270 thus controls the r.p.m. of percussion motor 166. To obtain the highest r.p.m. valve 270 is closed and valve 260 is opened to the motor 166. Where it is desired to decrease the speed of motor 166, the valve 270 is adjusted to by-pass a fixed volume of fluid supplied by pump 244.

In a similar manner the pump 246 has an outlet conduit 276 connected to a control valve 278. There is connected to conduit 276 by branch conduit 280 a flow control valve 282 similar to flow control valve 270. The flow control valve 282 has an adjusting handle 284 to vary the volume of fluid by-passed through outlet conduit 286 so that the speed of rotation of motor 198 can be controlled by the flow control valve 282. The valve 278 is similar to valve 260 in that it contains an integral adjustable pressure relief valve that by-passes fluid above a preselected pressure through outlet conduit 280 to reservoir 242. A suitable adjusting device 283 is schematically illustrated on valve 278 to vary the pressure relief setting for the adjustable pressure relief portion of valve 278. The valve 278 has a first conduit 285 connected to the rotary drive motor 198 and a second conduit 287 connected to the other inlet of the rotary drive motor 198. With this arrangement hydraulic fluid supplied through conduit 285 drives the shaft of motor 198 in one direction and alternatively supplies fluid through conduit 287 to rotate the shaft of motor 198 in the opposite direction. In the olf position, the fluid flows through valve 287 and outlet conduit 289 and returns to reservoir 242. A handle 288 is provided to control the flow of the hydraulic fluid through the valve 278 and has three positions. A first position directs the fluid to conduit 285, the second position directs the fluid to conduit 287 and in the third or off position permits the fluid to flow through valve 278 to outlet conduit 289 and reservoir 242.

With this arrangement, the torque of motor 198 can be controlled by handle 288 by increasing or decreasing the pressure relief setting in valve 278. The speed or r.p.m. of the motor 198 can be controlled by the flow control valve 282.

Pump 248 has its outlet connected through conduit 291 to the three position valve 290. The valve 290 is connected to the opposite ends of

cylinders

88 and 90 by

conduits

292 and 294. A by-pass outlet conduit 296 returns fluid to reservoir 242 above a preselected pressure by means of an integral pressure relief valve therein. The conduit 294 that supplies the front end of

cylinders

88 and 90 has an adjustable pressure relief valve 295 therein to vary the maximum pressure of the fluid supplied to the

cylinders

88 and 90 to retract the

piston rods

96 and 98. An outlet conduit 298 conveys the fluid from valve 295 to reservoir 242. By actuating handle 300 of valve 290, fluid under pressure can be supplied to the front end of

cylinders

88 and 90 through conduits 294 to retract the

pistons

96 and 98 and thus advance the drill carriage 34 and drill head 36 towards the front end of the feed carriage 32. The thrust exerted by the pistoncylinder arrangement is adjustable and is controlled by the adjustable pressure relief valve 295. Where it is desired to reduce the forward thrust on the drilling implement 38 the pressure relief valve 295 is adjusted to reduce the pressure at which the pressure relief valve will open and maintain a preselected maximum pressure in conduit 294. To retract the drilling implement from the mine face, the handle 300 of valve 290 is moved to supply hydraulic fluid through conduit 292 to the rear of the

cylinders

88 and 90 and to permit the fluid in the front of the cylinders to drain to outlet conduit 296 through conduit 294. There is also provided a position on valve 290 Where fluid is trapped in

conduits

292 and 294 to maintain the

piston rods

96 and 98 at a preselected position relative to the

cylinders

88 and 90 and thus maintain the drill carriage 34 and drill head 36 in a preselected location relative to the feed carriage 32.

It will be apparent that substantially the same operation of the percussion motor rotary drive motor and piston cylinder control could be obtained with manually controlled variable volume pumps. Variable volume pumps would eliminate the flow control valves that control the r.p.m. of the

respective motors

166 and 198.

According to the provisions of the patent statutes, we have explained the principle, preferred construction, and mode of operation of our invention and have illustrated and described what we now consider to represent its best embodiments. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim: 1. In a drilling machine the combination comprising, a drill head support member having a front end portion, a drill head mounted on said support member for longitudinal movement thereon, a drilling implement secured to said drill head and extending forwardly therefrom, said drill head support member front end portion having means to support said drilling implement as said drilling implement moves longitudinally relative to said support member, said drill head including thrust means to impart thrust forces in opposite directions to said drilling implement, said drill head including rotary drive means to impart high speed rotary motion to said drilling implement, and power operated means to advance said drill head longitudinally on said support member and impart forward thrust forces on said drilling implement during the drilling operation. 2. In a drilling machine as set forth in claim 1 in which,

said power operated means to advance said drill head longitudinally on said support member includes means to absorb the thrust forces exerted by said thrust means in a direction opposite to the direction of advance of said drilling implement so that said power operated means maintains a continued advancing force on said drilling implement in the direction of advance of said drilling implement. 3. In a drilling machine as set forth in claim 1 which includes,

a plurality of shafts rotatably mounted in said drill head, eccentric weights mounted on said shafts and operable upon rotation to impart thrust forces in opposite directions to said drilling implement connected thereto. 4. In a drilling machine as set forth in claim 3 which includes,

means to vary the frequency of the thrust forces imparted by said eccentric weights to said drilling implement connected to said drill head, and means to vary the magnitude of said thrust forces imparted to said drilling implement connected to said drill head. 5. In a drilling machine as set forth in claim 4 which includes,

means to vary the thrust forces imparted to said drilling implement during the drilling operation by said power operated means, and means to vary the speed of rotation of said drilling implement by said rotary drive means. 6. In a drilling machine having an extensible drill head support the combination comprising,

an elongtaed feed rack having a front end portion and a pair of parallel side members, support means for said feed rack, first power operated means to move said feed rack longitudinally on said support means, a drill head carriage mounted on said feed rack for longitudinal movement relative thereto, said drill head carriage having a pair of parallel spaced side members, a front end portion and a rear end portion,

second power operated means to move said drill head carriage longitudinally on said feed rack,

a drill head mounted on said drill carriage for longitudinal movement relative thereto,

an elongated drilling implement having a bit end portion secured to said drill head and extending forwardlly therefrom with said bit end portion extending beyond said feed rack front end portion,

said drilling implement supported by said drill carriage front end portion and said feed rack front end portion,

roller means rotatably secured to said drill carriage adjacent said front end portion,

flexible means connected at one end to the front end portion of said drill head and at the other end to said feed rack and having its intermediate portion reeved about said roller means so that movement of said drill carriage forwardly by said second power operated means moves said drill head forwardly on said drill carriage, and

said flexible element between said roller means and said drill head positioned in substantially the same plane as said drilling implement so that the reactive thrust force exerted on said drilling implement during the drilling operation is in the same plane as the thrust forces exerted by the flexible element on the drill head.

7. In a drilling machine having an extensible drill head support as set forth in claim 6 in which said second power operated means includes a piston-cylinder servomechanism,

said cylinder connected to said feedrack side members and extending longitudinally thereon,

said piston within said cylinder having a piston rod connected thereto and extending from said cylinder, the end of said piston rod connected to said drill carriage so that longitudinal movement of said piston within said cylinder moves said drill carriage on said feed rack, and the longitudinal axis of said cylinder being in substantially the same plane as the axis of said roller menas rotatably secured to said drill carriage front end portion so that the reactive thrust force exerted by said drill carriage during the drilling operation is in the same plane as the thrust forces exerted by the piston cylinder servomechanism.

8. In a drilling machine having an extensible drill head support as set forth in claim 6 in which,

said feed rack front end portion has an aperture therethrough,

said drill head carriage front end portion having an aperture therethrough aligned with said aperture in said feed rack front end portion, and

said drilling implement extending through said aligned apertures and supported by said feed rack front end portion and said drill carriage front end portion.

9. In a drilling machine having an extensible drill head support as set forth in claim 6 in which said drill head includes,

thrust means to impart thrust forces in opposite directions to said drilling implement, and

rotary drive means to impart high speed rotary motion to said drilling implement.

10. In a drilling machine having an extensible drill head support as set forth in claim 6 which includes,

said flexible element connected at one end to the front end portion of said drill head and at the other end to said feed rack including means to absorb the thrust forces exerted by said percussion means in a direction opposite to the direction of advance of said drilling implement so that said second power operated means maintains a continued advancing force 13 14 on said drilling iinplement in the direction of ad- 3,150,723 9/1964 Hale 173-147 X vance of said drilling implement. 3,181,630 5/1965 Coburn 173-147 X References Cited UNITED STATES PATENTS 2,102,603 12/1937 Pinazza 17349 3,023,820 3/1962 Desvaux et a1 173-49 X 173 49 3,146,836 9/1964 Lee 173-147 CHARLES E. OCONNELL, Primary Examiner 5 RICHARD E. FAVREAU, Assistant Examiner US. Cl. X.R.