US2781185A - Drilling apparatus - Google Patents

Description

Feb. 12, 1957 Filed June 2, 1954 D. ROBBINS DRILLING APPARATUS 5 SheetsSheet 1 II" II II II II II II II II II II INVENTOR DfiY/S ROBBINS v Zda j ATTORNEYS Feb. 12, 1957 D. ROBBINS 2,781,185

DRILLING APPARATUS Filed June 2, 1954 5 Sheets-Sheet 2 i i? f -1- Bf i wk 2212,

ATTORNEZE Feb. 12, 1957 D. ROBBINS 3 DRILLING APPARATUS Filed June 2, 1954 3 Sheets-Sheet 3 IN VENTOR 0/? W5 foam/V6 ATTORNEYS United States Patent 6 DRILLING APPARATUS Davis Robbins, Oneonta, Ala.

Application June 2, 1954, Serial No. 433,991

8 Claims. (Cl. 255-51) This invention relates to drilling apparatus and more particularly to means for drilling holes downwardly into the earth.

One object of my invention is to provide drilling apparatus which shall embody a transmission unit mounted for vertical movement in guideways and means to raise or lower the transmission unit in the guideways together with means connecting the unit in driving relation with a drill rod whereby the transmission unit moves downward as drilling proceeds.

Another object of my invention is to provide apparatus of the character designated including improved means for connecting and disconnecting drill rod sections to a movable transmission unit, together with a magazine mounted for pivotal movement at one side of the apparatus for holding a plurality of drill rod sections and disposed to move a section of the drill rod beneath the transmission unit.

further object of my invention is to provide apparatus for drilling holes downwardly into the earth which shall embody a hollow drill rod together with means for forcing air under pressure downwardly through the drill rod to clear the hole being bored of cuttings and to cool the drill bit.

A further object of my invention is to provide portable drilling apparatus having improved means associated therewith for leveling the same whereby the drill rod moves vertically into the earth.

A further object of my invention is to provide drilling apparatus of the character designated which shall have means associated therewith for discharging the cuttings from the hole being bored whereby the cuttings will not interfere with the operation of the apparatus.

A still further object of my invention is to provide apparatus for drilling holes downwardly into the earth which shall be durable, simple of construction, economical of manufacture and which may be readily moved from place to place and set up for the drilling operation in a minimum of time.

Apparatus embodying features of my invention is shown in the accompanying drawings forming a part of this application, in which:

Fig. l is a front elevational view, partly broken away and in section;

Fig. 2 is a side elevational view, partly broken away and in section;

Fig. 3 is an enlarged detail sectional view taken generally along the line III-III of Fig. 1;

Fig. 4 is a plan View partly broken away and in section, showing the means for discharging the cuttings from the hole being bored;

Fig. 5 is a sectional view taken generally along the line VV of Fig. 4;

Fig. 6 is a side elevational view, partly broken away and in section, showing the drill rod section which carries the cutting tool;

Fig. 7 is a plan view showing the means for moving the lower guides into and out of engagement with the drill rod, the drill rod being shown in section; and

Fig. 8 is a fragmental view showing the jack member for the front of the supporting vehicle.

Referring now to the drawings for a better understanding of my invention I show a supporting frame embodying lower and upper horizontal plates 10 and 11, respectively, connected by laterally spacedvertical frame members 12 and 13. The vertical frame members are provided withguideways 14 and 16 which extend the length thereof, as shown in Fig. 1. The horizontal plate 10 is secured rigidly to the rear end of a transporting vehicle, such as acaterpillar tractor 17 and is supported during the drilling operation byhydraulic jack members 13 and 19. Each of thejacks 18 and 19 comprises a fluid pressure operatedcylinder 21 having apiston rod 22 projecting from the lower end thereof. Connected to the lower ends of thepiston rods 22 are ground engagingshoe members 23.

Projecting forwardly of the front end of thetractor 17 are a pair of laterally spacedbrackets 24, only one of which is shown. Pivotally connected between thebrackets 24, by means ofpins 26, is a fluid pressure operatedcylinder 27 of ajack member 25. Projecting downwardly from thecylinder 27 is apiston rod 28 having a ground engaging shoe member 29 connected to the lower end thereof. To limit tilting movement of thecylinder 27 about its pivot point, aU-shaped bracket 31 is secured rigidly to the upper surface of thebrackets 24. The legs of the U-shaped bracket indicated at 32 and 33 are thus positioned on opposite sides of thecylinder 27 while thebase 34 thereof is positioned'above thecylinder 27. Secured to and connecting thebase 34 of the U-shaped bracket and the upper end of thecylinder 27 is a'tensionspring 36 which holds the cylinder in a substantially vertical position while the shoe member 29 is raised, such as when the apparatus is being moved from place to place. The forward portion of the.tractor 17 adjacent thejack 25 is connected to the upper plate 11 by means of abrace member 37 thereby adding strength to the supporting frame.

Mounted for vertical movement between theguideways 14 and 16 is atransmission unit 38 including ahousing 39. Secured to the ends of thehousing 39 areroller support members 41 which carryrollers 42 that engage opposite sides of theguideways 14 and 16, as shown in Fig. 2. Secured to thehousing 39 adjacent one end thereof is one flight of asprocket chain 43 which passes over upper andlower sprocket wheels 44 and 46 respectively. Thesprocket wheel 44 is keyed to atransverse shaft 47 which is mounted for rotation insuitable bearings 48 and 49 on the upper plate 11. Thesprocket wheel 46 is mounted for rotation in a U-shaped bracket 51 by means of a short shaft member 52. The bracket 51 is secured to the lower horizontal plate 11, as shown in Fig. 1. Connected to thehousing 39 adjacent the end thereof opposite thesprocket chain 43 is one flight of asprocket chain 53 which passes over an upper sprocket wheel 54 keyed to theshaft 47. The lower end of thesprocket chain 53 passes over asprocket wheel 56 mounted for rotation in aU-shaped bracket 57 by means of a short shaft 58. The U-shapedbracket 57 is also secured to the horizontal plate 10.

Mounted on theshaft 47 adjacent the ends thereof are plates which are secured to the upper ends ofpiston rods 64 and 66 of fluid pressure operatedcylinders 67 and 68. i The pivotal connections between therack members 62 and 63 and thepiston rods 64 and 66 permitlimited movement of the upper ends fthe rock members relative to I Patented lF'eb. 12,1957

thepinions 59 and 61 whereby the rack members maythe lower ends thereof for supporting :double flange.

rollers 65a which are positioned to engage opposite edges of the outermost portions of theframe members 12 and 13, as shown in Fig. 1, whereby the rack members andpiston rods 64 and 66 are held against movement outwardly of the frame members. To urge therack members 62 and 63 into engagement with thepinions 59 and 61 as the racks are raised and lowered by thecylinders 67 and 68,rollers 69 and 71 are mounted for rotation inbrackets 72 and 73 respectively, on the plate 11 at the side of the racks opposite the pinions. As theracks 62nd 63 are raised or lowered by the cylinders thepinions 59 and are rotated thereby causing raising or lowering of thesprocket chains 43 and 53 through the shaft 4-? thesprocket wheels 44 and 54. Thetransmission unit 38 is thus raised or lowered by causing thesprocket chains 43 and 53 to move in the required direction.

Connected to the power unit of thetractor 17 is ahorizontal shaft member 74 having abevel gear 76 mounted at the outer end thereof. Meshing with thebevel gear 76 is abevel gear 77 which is secured to the lower end of avertical shaft 78 having a polygonalupper portion 79 which extends through suitable openings in thehousing 39 of the transmission unit, as shown in Fig. 3. Asuitable shear pin 80 is provided in theshaft 73 which shears when the drill strikes a crevice or other obstruction.

Mounted within thehousing 39 of the transmission unit '38 and adapted to slide vertically along thepolygonal portion 79 of theshaft 78 is asprocket wheel 31 having annular flanges $2 and 83 which slidably engage the inner surface of thehousing 39, as shown. The upper end of theshaft 78 rotates in a suitable bearing 84 mounted in the upper plate 11.

Passing through thehousing 39 of thetransmission unit 38 and mounted for rotation relative thereto is ahollow driving head 36. Secured to the drivinghead 86 within thehousing 39 is asprocket wheel 87. Asprocket chain 88 connects thesprockets 81 and 87 and transmits power from theshaft 78 to the drivinghead 86.

Mounted at the lower end of the drivinghead 86 is afemale coupling 89 which is adapted to receive amale coupling 91 at the upper end of a hollow drill rod section indicated at 92. The lower end of the drill rod section is provided with a female coupling 93 for receiving the male coupling of alower section 92 of the drill rod.

-As shown in Fig. 6, the first drill rod section which enters the ground, indicated at 92a, is provided with adrill collar 94 having spiral flukes 94a thereon which causes the cuttings from the hole being bored to move in a spiral path about the outer surface of the drill rod and limits lateral shifting of the drill bit, thereby preventing excessive wear at the sides of the bit. Thedrill rod section 92a is provided with a female coupling at its lower end 1 for receiving a threaded male coupling of adrill bit 95.

Connected to the upper end of the hollow drivinghead 86 by means of an airswivel joint 109 is ahose 96 which communicates with a suitable compressor, not'shown, for

. pins 114 and 116, respectively.

.are secured to thebars 104 and 106, respectively. Pivotally connected to the upper ends of thepins 109 and 111 arelever arms 112 and 113 which are fulcrumed to the upper surface of thehousing members 101 and 182 by Secured .to the inner ends of thebars 104 and 106 are arcu-ateguide members 117 and 118 which partially surround the drill rod sections, as shown in Fig. 7.Rollers 119 are mounted for rotation on the inner surface of thearcuate members 117 and 118 in position toengage the drill rod sections as the same is rotated by the drivinghead 86. The 'arcuate guide members 117 and 118 are moved into and out of engagement With the drill rod section by the lever arms 112 and. 113 and openings 121 are provided in thebars 104 and 106 for receiving suitable pins whereby therollers 19 of the arcuate members are held in engagement with the drill rod section during the initial drilling operation. Also,openings 122 are provided in thebars 104 and 106 for receiving suitable pins which engage the outer ends of thehousing members 191 and 1112 to limit inward movement ofbars 104 and 106, whereby thearcuate members 117 and 113 are held out of engagement with the drill rod sections, while sections are being added or removed and after the hole has been bored a distance to prevent lateral shifting of the drill rod section.

Additionaldrill rod sections 92 are carried in a maga to the under surface of the horizontal plate 11, as shown 'in Fig. l.

The lower end oftheshaft 129 is secured to the horizontal plate 18. Thearm members 127 and 128 supplying air under pressure to the hollow driving head.

.bars 104 and 106, which are substantially square as viewed incross section.Elongated openings 107 and 108 are provided in the upper Wall of the housing members-101 and 102 for receivingpins 109 and 111 which are also connected bysuitable brace members 132.

'Themagazine 123 is provided with an annularrow of cup-shapedmembers 133 adjacent the lower end thereof for receiving the lower ends of thedrill rod sections 92. The upper ends of thedrill rod sections 92 are held in the magazine by means ofU-shaped members 134 having latcnmembers 136 mounted for pivotal movement adjacent the outer end of one of the legs of eachU-shaped member 134. A suitable notch 137 is provided in the other leg of each U-shaped member for receiving the free end of thelatch member 136, as shown in Fig. 1. Due to the fact that the magazine rotates inbearings 124 and 126 at the outer ends of arm members 127. and 123 which in turn are mounted for rotating movement about thevertical shaft 129, each drill rod section may be positioned directly beneath the drivinghead 86 by merely rotating the arm members about theshaft 129 and then rotating the magazine in thebearings 124 and 126.

Surrounding thedrill rod section 92 beneath the horizontal plate 10 is a discharge housing member 133'having abottom wall 139,side Walls 141 and a top or cover 142 formed of a resilient material. Theside walls 141 are provided with an outwardly extendingflange 143 for supporting the outer edge of the flexible cover 1 :2. Ametallic strip 144 surrounds thecover 142 and is secured to theflange 143 by any suitable means such as rivets orbolts 146, thereby securing the flexible cover to the flange 14-3.Openings 147 and 148are provided in the bottom and cover, respectively, of the housing for receiving thedrill rod sections 92 or 92a, as the case may 153 is' a packing member in the form of aresilient ring 154 having downwardly tapered side walls which engage the upwardly flaringflange 153, as shown in Figs. 1 and 5. Thering member 154 is split at one side thereof as at 165 whereby it may be slipped around a drill rod section. Thering member 154 is provided with anopening 156 therein which is provided with an enlarged diameter portion 157 adjacent the lower end thereof. Fitting within the enlarged diameter portion 157 and secured to thering member 154 is anannular sealing member 158 having a downwardly and inwardly extendingflange 159 which engages the outer surface of thedrill rod 92 to form an air tight seal therewith. Thehousing 138 is provided with anoutlet conduit 161 for discharging the cuttings from the hole being bored.

Fitting over thering member 154 is aclamp ring 162 which is in the form of a pair ofsemi-circular members 163 and 164 pivotally connected at one side thereof by means of abolt 166. Projecting outwardly from themembers 163 and 164 arehandle members 167 and 168, respectively. Theclamp ring 162 is locked in place by means ofbracket members 169 and 171 mounted at opposite sides of theannular member 152, as shown in Figs. 1 and 4. Thebrackets 169 and 171 are provided with oppositely disposed horizontal slots therein for receiving thehandle members 167 and 168 when theclamp ring 162 is rotated in a counterclockwise direction, as viewed in plan.

To support thedrill rod sections 92 while the uppermost one is being removed, I securetransverse pipe sections 172 to the walls of thedrill rod section 92 adjacent the upper ends thereof. Thepipe sections 172 connect opposite sides of the drill rod sections, there being suitable openings in the drill rod sections for receiving thepipe sections 172 as shown in Figs. 1 and 6. Thepipe section 172 is joined to the walls of thedrill rod section 92 by any suitable means, such as by welding, whereby there is no escape of air as the air passes downwardly through the drill rod section. Mounted on the undersurface of the horizontal plate by any suitable means, such as by welding, is a rearwardly extendingbracket 174 having acylindrical sleeve member 176 secured to the outer end thereof. Thesleeve member 176 is in position to receive a suitable bar member which passes through theadjacent pipe section 172 to support the drill rod sections remaining in the hole being bored while the uppermost section is being removed. By providing thetransverse pipe sections 172, there is a relatively long bearing area for the bar member which passes therethrough, thus preventing excessive wear to the walls of the drill rod sections.

Atransverse pipe section 173 similar in all respects to thepipe section 172 is provided adjacent the lower end of the drill rod sections for receiving a suitable bar, whereby the uppermost drill rod section may be held against rotation while thefemale section 89 of the drivinghead 86 is unscrewed from or screwed onto themale coupling 91. Preferably, thepipe sections 172 and 173 are positioned at substantially right angles to each other, as shown. Thefemale sections are screwed onto and unscrewed from the male sections by rotating the drivinghead 86 in reverse directions.

Thevertical frame members 14 and 16 are provided withjoints 177 and 178 whereby the upper portions thereof may be moved downwardly onto thetractor 17 when the apparatus is being transported a great distance on another vehicle, such as a truck or the like. Asuitable hinge 179 connects the upper and lower portions of thevertical frame members 14 and 16, as shown in Fig. 2. In view of the fact that thejacks 67 and 68 are carried by the upper portion of theframe members 14 and 16 and are not connected to the lower portions thereof, they move with the upper portions as the upper portions move toward lowered and raised positions. Thevertical shaft 129 carrying themagazine 123 is disconnected from the remainder of the apparatus when the upper portions of the frame members are lowered onto the tractor. 17. 7

vertical frame members are held in upright position while the apparatus is in operation by means of thebrace member 37 and byhorizontal bracket members 181 and 182 welded to the upper and lower portions of the vertical members, respectively. Thebracket members 181 and 182 are attached to each other by means ofbolts 183, as shown in Fig. 1. To raise and lower the upper portions of theframe members 12 and 13, a fluid pressure operatedcylinder 184 is pivotally mounted on the plate 10. Projecting outwardly of the upper end of thecylinder 184 is apiston rod 186 which is pivotally connected to the frame members.

From the foregoing description, the operation of my improved drilling apparatus will be readily understood.

The apparatus is transported to the area where the holes are to be bored, such as a strip mining area, and thevertical frame members 14 and 16am moved to the upright position by means of thecylinder 184. Thebrace member 37 is mounted between the upper plate 11 and the tractor 1'7 and thebolts 183 are installed thereby locking the upper portions of the vertical frame members to the lower portions thereof. The apparatus is then moved by thetractor 17 to the position where a hole is to be drilled into the earth. Theshoe members 23 and 29 are lowered into engagement with the ground and the apparatus is then leveled by raising or lowering thejacks 18, 19 and 25 as required.

With the apparatus thus leveled, thearms 127 and 128 carrying themagazine 123 are swung around and the magazine is rotated so as to position the drill rod section 92:: beneath the drivinghead 86. The drivinghead 86 is then rotated in a direction to screw thefemale coupling 89 onto the male coupling at the upper end of the drill rod section 920. Thearcuate guidemembers 117 and 118 are moved into engagement with the outer wall 1 of the drive rod section, as shown in Fig. 7. A shallow hole is then drilled into the ground by rotating the drivinghead 86 through the medium of thesprocket chain 88, theshaft 78 and the drivingshaft 74 which is connected to thetractor 17. After the shallow hole is drilled into the earth, the guide members are moved out of engagement with thedrill rod section 92a and the section is raised by actuating the pressure operatedcylinders 67 and 68 in a direction to raise theracks 62 and 63, thereby raising the flights of thesprocket chains 43 and 53 which are attached to thetransmission unit 38. With thedrill rod section 92a thus raised, thering member 152 in thedischarge housing 133 is positioned beneath therecess 97 in the lower plate 10 and the drill rod section 92:: is passed downwardly through thering member 152 and theopening 147. The resilientsplit ring member 154 is then placed around the drill rod section, as shown in Fig. 5 with the inwardly extendingflange 159 in sliding contact with the outer surface of the drill rod. Theclamp ring 162 is then placed around the drill rod section and rotated in a counterclockwise direction whereby it engages thebrackets 169 and 171 and locks theresilient packing member 154 within theannular member 152. By providing aresilient cover 142 for thedischarge housing 138, the drill rod section remains in a vertical position while the housing accommodates itself to the contour of the earth surrounding the hole being bored.

With thedischarge housing 138 thus mounted beneath the plate 18, thecylinders 67 and 63 are actuated to cause rotation of thesprocket chains 43 and 53 in a direction to lower thetransmission unit 38 together with thedrill rod section 92a. The drivinghead 86 and the drill rod section are then rotated by thesprocket chain 88, theshaft 78 and thedrive shaft 74. When theupper pipe section 172 in thedrill rod section 92a moves to a position opposite thesleeve member 176, a suitable bar is placed through the sleeve member and the pipe section, thereby holding the drill rod section against rotation and supporting the same. With the drill rod section locked in place by the rod, the drivinghead 86 is rotated in a reverse direction to unscrew thefemale coupling 89 from the male coupling of thedrill rod section 92a. Thetransmission unit 38 is raised and the magazine is swung around to position adrill rod section 92 beneath the drivinghead 86. The drivinghead 86 is then rotated in a direction to screw thefemale coupling 89 thereof down onto themale coupling 91 of thedrill rod section 92. The female coupling at the lower end of thedrill rod section 92 is then screwed onto the male coupling at the upper end of the drill rod section 92:; by rotating the drivinghead 86. Thecylinders 67 and 68 are next actuated so as to raise the transmission unit 38 a slight distance whereby the rod member may be removed from thepipe section 172 and thesleeve member 176. Continued rotary motion is imparted to thedrill rod section 92 until thepipe section 172 moves to a point opposite thesleeve member 176, whereupon another drill rod section is added as described above.

As the drill rod sections are rotated thedrill bit 95 cuts into the earth. Compressed air is introduced through thehose connection 96 and flows downwardly through the drivinghead 86 and the hollowdrill rod sections 92 and 92a thence out through the male coupling of thedrill bit 95 where it picks up'the cuttings from the hole being bored and conveys them upwardly about the outer surface of the drill rod section to thedischarge housing 138 where the cuttings are discharged through theconduit 161. The downwardly and inwardly extendingflange 159 on the sealing member 155 prevents air and the cuttings from being blown out around the drill rod sections.

To remove the drill rod sections from the drilled hole, thetransmission unit 38 together with the drill rod sec- 'tions are raised by actuating thecylinders 67 and 68. The bar is inserted through thesleevemember 176 and thepipe section 172 of the seconddrill rod section 92 whereby it is held against rotation and supported. The female joint at the lower end of the uppermostdrill rod section 92 is then unscrewed from the male coupling at the upper end of the second drill rod section by reversing the direction of rotation of the drivinghead 36. Themagazine 123 is then swung around into position to receive the drill rod section which is attached to the drivinghead 86. A suitable bar is then placed through thepipe section 173 at the lower end of thedrill rod section 92 thereby holding the same against rotation while the drivinghead 86 is rotated in a direction to unscrew thefemale coupling 89 from themale coupling 91. The magazine is then swung outwardly to the position shown in Fig. 1. With the uppermostdrill rod section 92 removed, thetransmission unit 33 is lowered by thecylinders 67 and 68 to place thefemale coupling 89 of the driving head into engagement with the male coupling of the next drill rod section. The driving read 86. is then driven in a direction to screw thefemale coupling 89 thereof onto the male coupling of the next drill rod section. Thetransmission unit 38 together with the drivinghead 36 and the drill rod sections are then raised by actuating thecylinders 67 and 68 and the second drill rod section is removed in the same manner as the first. This procedure is continued until all of the drill rod sections are removed from the opening and placed in 'the magazine.

After all of the drill rod sections have been removed from the hole, theannular sealing member 154 of thedischarge housing 138 is removed by rotating theclamp ring 162 in a clockwise direction. Thedrill bit 95 is then passed upwardly through theannular member 152. Thedischarge housing 133 is then removed from beneath the plate 1% and is transferred to anew location Where a hole is to be bored. The shoes of thehydraulic jacks 18, 19 and 25 are next lifted by actuating thecylinders 21 and 27. The apparatus is then transferred by From the foregoing it will be seen that I have devised an improved apparatus for drilling holes downwardly into the earth. By providing portable drilling apparatus. together with improved means for connecting and disconnecting drill rod sections, my apparatus is particularly adapted for drilling holes for explosives in strip mining areas. Also, by providing hollow drill sections together with means for forcing compressed air downwa'rdly through the same and the drill bit, the cuttings are removed immediately from the hole and the drill head is cooled continuously. Furthermore, by providing a vertically movable transmission unit together with 1 -eans to drive the same from a polygonal shaft during the vertical movement, my apparatus is simple of construction, economical of manufacture and requires a minimum of personnel to operate the same.

In actual practice I have found that my improved apparatus is satisfactory in every respect and that the same may be moved from place to place and set up for operation in a very short period of time. Also, I have found that the actual drilling time required, after the apparatus is set up, is reduced materially over apparatus heretofore known to me.

While I have shown my inventionin but one form, it will beobvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is: V a

1. Drilling apparatus for drilling holes ,downwardl into the earth comprising a vertical frame, vertical guideways in the frame, a polygonal rotary driving shaft mounted to rotate in the frame and carried thereby, means for rotating said driving shaft, a transmission unit mounted for vertical movement in the guideways, means connecting the transmission unit in driving relation with the polygonal shaft,'a hollow drill rod adapted to convey air from an air pressure source downwardly to clear the hole being bored of cuttings, a hollow drill bit connected to' the lower end of the drill rod, meansdetachably connecting the drill rod to and driving the same from the transmission unit, a discharge housing for said cuttings surrounding the drill rod adjacent the lower end of the vertical frame, and power means connected to the transmission unit to raise the transmission unit in the guideways and to lower the transmission unit as drilling proceeds.

2. Drilling apparatus as set forth in claim 1 inwhich the drill rod is sectional and in which a magazine for holding sections of the drill rod is pivotally mounted alongside the frame in position for a section of the drill rod and a portion of the magazine to be swung between the guideways beneath the transmission unit to be connected thereto.

3. Drilling apparatus as set forth in claim 1 in which the guide means for the drill comprises a pair of horizontally extending arcuate members having rollers mounted for rotation along the inner surfaces thereof and positioned to receive the drill rod therebetween and means for moving said arcuate members whereby the rollers move into and out of engagement with said drill rod.

4. Drilling apparatus for drilling holes downwardly into the earth comprising a vertical frame, vertical guideways in thefrarne, a transmission unit mounted for vertical movement in said guideways, power means for raising and lowering said transmission unit, a vertical rotary driv-.

to said transmission unit for driving the same, a hollow driving head driven by the transmission unit, a hollow drill rod adapted to convey air from an air pressure source downwardly to clear the hole being bored of cuttings, a hollow drill bit connected to the lower end of the drill rod, means connecting an air pressure source to said hollow driving head and means for connecting the driving head to the upper end of the drill rod,

5. Drilling apparatus as defined inclaim 4 in which the power means for raising and lowering the transmission unit comprises vertically extending endless sprocket chains mounted for rotation in the same direction adjacent each side of the transmission unit, means connecting one flight of each of said chains to said transmission unit, a drive shaft mounted for rotation adjacent the upper end of the vertical frame, sprocket wheels on said shaft for driving the sprocket chains in the same direction, at least one pinion mounted on said shaft, a rack mounted on the vertical frame in position to engage and rotate said pinion, and fluid pressure operated means for moving said rack relative to said pinion.

6. Drilling apparatus for drilling holes downwardly into the earth comprising a vertical frame, vertical guideways in the frame, a transmission unit mounted for vertical movement in said guideways, power means for raising and lowering said transmission unit, a rotary driving shaft connected to said transmission unit for driving the same, means for rotating said driving shaft a sectional drill rod comprising a plurality of individual hollow sections, a hollow drill bit connected to the lower end of the drill rod, means to connect the individual sections and to drive the drill rod from the transmission unit, means introducing air from an air pressure source downwardly through the hollow drill rod and the drill bit, seal-means positioned outwardly of and adjacent the upper end of the hole being bored and surrounding the drill rod for discharging air moving upwardly through the hole together with the cuttings entrained with the upwardly moving air, and support means on said frame adapted to engage the drill rod and support the lower sections of the drill rod while the uppermost section is being removed.

7. Drilling apparatus as defined in claim 6 in which the means for supporting the lower sections of the drill rod while the uppermost section is being removed comprises a pipe section extending transversely through the upper portion of each drill rod section, a bracket secured to the lower portion of the frame, a sleeve member secured to said bracket and positioned opposite said pipe section, and a rod-like member disposed to pass through said sleeve member and said pipe section.

8. Apparatus as set forth inclaim 7 in which transversely extending pipe sections are also provided in the lower portion of the individual drill rod-like member sections for receiving a rod whereby the uppermost section may be held against rotation while it is being disconnected from the transmission unit.

References Cited in the file of this patent UNITED STATES PATENTS 1,065,409 Van Sickle June 24, 1913 1,242,305 Arey Oct. 9, 1917 2,114,305 Johansen Apr. 19, 1938 2,145,939 Markley Feb. 7, 1939 2,202,446 Esseling May 28, 1940 2,215,928 Hornbrook Sept. 24, 1940 2,527,255 Hunt Oct. 24, 1950 2,557,049 Haines June 12, 1951 2,594,098 Vanderzee Apr. 22, 1952 2,660,403 Roland Nov. 24, 1953

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