US3061288A

US3061288A - Steering means for rotary head tunneling machine

Info

Publication number: US3061288A
Application number: US820200A
Authority: US
Inventors: William W Miller
Original assignee: Goodman Manufacturing Co LP
Current assignee: Goodman Manufacturing Co LP
Priority date: 1959-06-15
Filing date: 1959-06-15
Publication date: 1962-10-30
Anticipated expiration: 1979-10-30
Also published as: GB944612A

Description

OC- 30, 1962 J. s. RoBBlNs 3,061,288

STEERING MEANS FOR ROTARY HEAD TUNNELING MACHENE;

Jmes 3. Robbins, Deceased),

AT TORNEV Oct. 30, 1962 J. S. ROBBINS STEERING MEANS FOR ROTARY HEAD TUNNELING MACHINE Filed June l5. 1959 7 Sheets-Sheet 5 OOOOOOO A^\ y A James S. Robbins}Deceased,

77W 4. @eww J. S. ROBBINS Oct. 30, 1962 STEERING MEANS FOR ROTARY HEAD TUNNELING MACHINE '7 Sheets-Sheet 4 Filed June l5, 1959 ATTORNEY' Oct. 30, 1962 J. s. RoBBlNs 3,061,288

STEERING MEANS EoR ROTARY HEAD TUNNELING MACHINE Filed June 15, 1959 '7 sheets-sheet 5 47W@ www ATTORMEV Oct. 30, 1962 J. s. RoBBlNs 3,051,288

STEERING MEANS FOR ROTARY HEAD TUNNELING MACHINE Filed June l5, 1959 7 Sheets-Sheet 6 1NVENTOR.

BYW/'l//am W. Mil/er flecuor y AT OEV J'mes S. Robbl'nsQDeceased, I

Oct. 30, 1962 J. s'. RoBBlNs 3,061,288

STEERING MEANS FOR ROTARY HEAD TUNNELING MACHINE Filed June 15, 1959 7 Sheets-Sheet 7 United States 3,061,288 STEERING MEANS FR ROTARY HEAD TUNNELING MACHINE James S. Robbins, deceased, late of Seattle, Wash., by

William W. Miller, executor, Northfield, Ill., assignor to Goodman Manufacturing Company, a corporation of Illinois Filed June 15, 1959, Ser. No. 820,200 9 Claims. (Cl. 2627) This invention relates to improvements in tunneling machines of the rotary boring head type, and more particularly relates to such machines adapted to bore directly "into relatively hard minerals, such as rock and the like.

A principal object of the invention is to provide a simpler and more eicient rotary tunneling machine of the class described adapted to -bore relatively large diameter tunnels in `a straight or curved line.

Another object of the invention is to provide an improved form of rotary tunneling machine in which the main frame of the machine is articulated and in which the articulated parts of the main frame may be `held in fixed relation with respect to each other at various angles with respect to the axis of rotation of the boring head, to effect the boring of a tunnel in a straight as well as in a curved line.

A still further object of the invention is to provide a tunneling machine having a rotary `boring head and an elongated main yframe extending rearwardly therefrom and positively supported and guided adjacent its rear end for movement along the tunnel wall, in which steering of the boring head is attained by lateral movement of the rear end portion of the main frame with respect to the positive guide means therefor.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

FIGURE 1 is a top plan View of a tunneling machine constructed in accordance with the invention, showing the machine in operation in a tunnel;

FIGURE 2 is a view in side elevation of the machine shown in FIGURE 1 with certain parts broken away and certain other parts shown in #vertical section;

FIGURE 3fis a rear end view of the machine with certain parts broken away and certain other parts shown in section;

FIGURE -4 is a transverse sectional View taken substantially along line 4 4 of FIG. 2.

FIGURE 5 is a transverse sectional view taken substantially along line 5-'5 of FIGURE 4;

FIGURE 6 is an enlarged fragmentary plan View of the machine looking at the machine just rearwardly of the boring head, with certain parts shown in section in order to illustrate the feeding means for the boring head;

FIGURE 7 is a diagrammatic View showing the tunneling machine driving a tunnel along an arcuate path;

FIGURE 8 .is an enlarged fragmentary plan View of the central part of the machine illustrating the articulated connection for the main frame of the machine, accommodating the machine to drive a tunnel along an arcuate path;

FIGURE 9 is a fragmentary vertical sectional view taken substantially along line 9-9 of FIGURE 3;

FIGURE 10 is a fragmentary vertical sectional view `taken substantially along line lil-10 of lFIGURE 3; and

FIGURE l1 `is a fragmentary view in Side elevation of one of the supporting carriages for the main frame `of the machine, looking substantially along line 1111 of FIGURE 3.

In the embodiment of the invention illustrated in FIG- URES 1 and 2 of the drawings, a Ytunneling machine `10 is shown in the operation of driving a tunnel in rock 3,061,288 Patented Oct. 30, 1962 and the like. The tunneling machine lil-generallyincludes a rotary cutter nor boring head 11 rotatably mounted at the frontend of an elongated main frame 12, commonly called a jumbo, and supported at its rear end on a carriage 13 including widely spaced trucks 15 having angedwheels 16 riding along rails 17, mounted on longitudinally spaced ring beams 19 extending about and reenforcing `the tunnel wall in a conventional manner.

The machine is mounted at its forward end for slidable movement along the ground on a boring head support and shield 2t), having a generally cylindrical wall portion 21 extending about the rear end portion of the boring head. The shield 20 is shown in FIGURE 4 as comprising a plurality of abutting segments 23, andas having a plurality of Wall engaging shoes 24, recessed within and forming continuations of the wall 21. As herein shown, three similar wall engaging shoes 24 Vare provided, one engaging the bottom of the tunnel wall and the others engaging opposite sides of the tunnel Wall just beneath `the center line thereof.

The shoes 24, as shown in FIGURES 2 and 5 extend to Va position closely adjacent the boring head 11 and are guided in box-like guides 25 extending angularly from a peripheral wall 26 of a boring head support portion 23 of the shield 20, and forming supports and closures for Vhydraulic jacks, including cylinders 27 having pistons 29 movable therealong. The pistons 29 are shown in FIG- URE 5 as having connecting lugs 30 extending therefrom between spaced ears 31, extending angularly from the shoes 24, and pivotally connected thereto as by a pivot pin 32.

The bottom shoe 24 may thus tilt the boring head a limited amount, adjacent the forward end thereof, while the side shoes 24 may move the boring head a limited amount from side to side, to maintain the boring head in the required path and to aid in freeing the boring head in cases where it may become jammed inthe tunnel wall.

A means is provided to lift the forward end portion of the machine in cases where the bottom may be soft and the forward end portion of the machine may bog down in the bottom. This means is shown in FIGURE 2 as including a cylindrical guide 33 mounted on the main frame 12, just rearwardly of the shield 20, and vhaving a hydraulic jack 35 extending therealong and pivoted thereto adjacent its upper end. The hydraulic jack 35 has operative connection with a slide 36 slidably guided in the cylindrical guide 33 and adapted to carry a truck 37 at its lower end, shown in dotted lines in FIGURE 2.

A cylindrical guide 3-3, hydraulic jack 35 and slide 36 is provided at each side of the main frame 12. The trucks 37, however, are normally not carried by the slides 35 but are only provided Where the front end of the machine may be bogged down in soft bottom. It is, of course, understood that under such conditions the rails 17 are yextended along the ring beams 19 to positions adjacent the boring head support and shield 20, to accommodate the hydraulic jacks 35 to lift the forward end portion of the machine and to support the forward end portion of the machine, .during the tunneling operation.

A platform 39 4extends rearwardly of the main frame 12 adjacent one side thereof and forms a support for a crane 40, provided to lift the ring beam segments 19 and place Ythem on slidable rails 41 at the top of the main frame 12, and extending along said main frame toward a lift 43, for assembly along the tunnel wall.

The main frame or jumbo 12 is a generally rectangular cross-braced frame structure and includes a front part extending rearwardly from the boring head support and shield 20, and a rear part 101 pivotally connected thereto for movement about a vertical axis. As shown in FIGURES 2 and 10, the front part 100 of the main frame includes parallel spaced longitudinally extending lower beams 103 connected togethed at their rear ends by a transversely extending beam 104. The front part also includes parallel spaced longitudinally extending upper beams 105 extending rearwardly of the boring head support and shield 20, and connected together at their rear ends by a transverse beam 106.

The rear part 101 of the main frame 12, as shown in FIGURE l0 includes parallel spaced longitudinally extending lower beams 107 connected together by a rear transverse beam 109.

The rear part 101 of the main frame 12 also has parallel spaced longitudinally extending upper beams 110 connected together by a rear transverse beam 111 (FIG- URE 8).

The beam 106 is shown as having a gusset or pivot plate 112 suitable mounted thereon at the transverse center thereof and extending rearwardly therefrom beneath a gusset or pivot plate 113 suitably mounted on the beam 111 and extending forwardly therefrom. The

plates

112 and 113 are pivotally connected together as by a pivot pin 115 intersecting the longitudinal axis of the machine. The lower

transverse beams

104 and 109 likewise have

pivot plates

116 and 117 extending rearwardly and forwardly therefrom respectively, and pivotally connected together by a pivot pin 119.

The adjacent ends of the

upper beams

105 and 110 are shown as having transversely extending

vertical bearing plates

120 and 121 mounted on the respective ends thereof and inclined with respect to the ends of said beams. As shown in FIGURE 8 the

bearing plates

120 and 121 on the left hand side of the main frame 12 are connected in abutting relation with respect to each other by nuts and bolts 123. The

bearing plates

120 and 121 at the opposite side of the main frame 12 are spaced apart by spacer blocks 124, and are connected together by nuts and bolts 125, permanently connecting the

frame parts

100 and 101 together out of aligned relation with respect to each other, and positioning the front frame part and boring head to bore a tunnel along an arc, as diagrammatically shown in FIGURE 7.

In FIGURE 6, the

lower beams

103 and 107 are shown as having transversely extending

vertical abutment plates

126 and 127 connected to the adjacent ends thereof and abutting spacer blocks or wedges 129, and secured in abutting engagement with said spacer blocks or wedges, 'by nuts and bolts 130. With the wedge arrangement shown in FIGURE 6, the front and rear frame parts are connected together in aligned relation with respect to each other, positioning the boring head 11 to bore a tunnel along a straight line.

It will be understood that various wedging arrangements may be used for permanently fixing the front and rear frame parts of the main frame 12 in axial alignment with respect to each other, or out of alignment with respect to each other, as desired, to position the boring head 11 to bore along a straight line or an arc as required.

Referring now in particular to FIGURES 1 and 10 Aand the means for feeding the boring head 11 into the tunnel face, a pair of hydraulic feeding jacks 131 are provided. The hydraulic feeding jacks 13-1 as shown in FIG- URE 6, include hydraulic cylinders 132 having connectors 133 extending `from the head ends thereof and extending between connectors 135 extending rearwardly of the plate 95 of the boring head support and shield 20, and pivotally connected to said connectors 135 by vertical pivot pins 136. The cylinders 132 extend within housings 137, which may be cylindrical in form, and which are guided for movement with respect to the frame part 100 on longitudinally spaced rollers 139, mounted on the outer wall of said housings and extending within channel-like guide members 140, extending along each side of the front frame part 100.

The cylinders 132 have piston rods 141 extensible therefrom, connected at their outer ends between vertically spaced connectors 143 on pins 144. The connectors 143 are apertured at their outer ends to accommodate exible cables 145 to be connected thereto, to withdraw the boring head 11 from the tunnel face, when desired. When withdrawing the boring head 11 from the tunnel face, tlexible cables 145 may be connected to either or both `connectors at their advance ends and to certain ring beams 19 at their rear ends. Thus, when uid under pressure is admitted to the piston rod ends of the cylinders 132, the entire machine may be withdrawn from the tunnel face, it being understood that during the withdrawing operation, the housings 137 are free to move longitudinally of the front frame part 100. It should also be understood that one housing 137 may be xedly connected into abutting engagement with a ring beam 19, as by an abutment or reaction jack 147, while the other housing may be free. Thus, when the flexible cable is connected between the connector 143 of the free housing and a ring beam 19, as shown in FIGURE l, the entire forward end portion of the machine may be moved to one side or the other a limited amount determined by the clearance between the peripheral wall 21 of the shield 20, and the tunnel wall.

The abutment jacks 147 are shown as being screw jacks having screws 149 threaded within nuts 150 on the outer ends of housings 151 for the jacks, and having hand grips 153 extending outwardly therefrom, to accommodate turning of the nuts by hand. An angular abutment member 154 is shown as being pivotally connected to the outer end of the screw 149, to abut a ring beam 19 and react thereagainst.

The housing 151 of each screw jack 147 has a bifurcated advance connecting portion 155, the furcations of which extend along opposite sides of the housing 137 and are trunnioned thereto as by trunnion pins 156.

Thus, when the abutment members `154 are engaged with a ring beam 19 at opposite sides of the tunnel wall, and retained in fixed engagement therewith by taking up on the jacks 147, and when fluid under pressure is admitted to the head ends of the cylinders 132, the cylinders 132 will extensibly move with respect to the housings 137 rto effect advancing or feeding movement of the boring head into the tunnel face `for the length of stroke of said piston. At the end of one feeding operation, determined by the length of stroke of the piston 132, the jacks 147 may be released and uid under pressure may be admitted t-o the piston rod ends of the cylinders 132, to advance the housings 137 along said cylinders to the ends of the strokes of the piston rods 141. The jacks 147 may then be placed into abutting engagement with an `advance ring beam 19, and the feeding operation may then be continued.

Referring now to the carriage 13 and the means for steering the machine laterally and up and down, the carriage 13, as shown in FIGURES 3, 9, l0 and ll, includes an upper transversely extending beam 159, forming a slidable support for the rear frame part 101 of the main frame 12. As shown in FIGURES 3 and 9 the under sides of beams 158 slidably supported on bearing plates 162 extending along the top of the beam 159.

Bearing shoes

160 and 160a slidably engage opposite sides of said beam (FIGURE 9).

The beam 159 is supported on the upper ends of vertically extending housings 161 extending vertically of said upper beam. The housings 161 form housings for hydraulic jacks 163, including cylinders 164 pivoted at their head ends to connectors `165 on pivot pins 166. The connectors 165 and pivot pins 166 suspend the hydraulic jacks 163 from the top portions of said housing to extend within hollow columns or posts 167, mounted on the trucks 15.

Each cylinder 164 has a piston rod 169 depending therefrom and extensibly and retractably movable with respect thereto. Each piston rod 169 is connected to a horizontal interior wall 170 of a post 167, to effect raising anciens and lowering of the transverse beam 159 and Itilting of the boring head 11 about the forward end portion of the shoe 24, to vary the vertical inclination of fthe tunnel. The housings 161 are spaced apar-t adjacent their lower end portions by a transverse beam l173, connected to the .beam 159 by a series of angularly extending truss inembers 174, to lend rigidity to the carriage 13. The beam 173 forms a support for laterally slidable shoes 175 mounted on the rear frame part 101 of the main frarne 12.

Each truck 15 includes a bolster plate 176 having laterally spaced parallel depending side walls 177, having a cradle 179 pivotally mounted therebetween on a transverse pivot pin 180 (FIGURE 1l).

Rockable carriers 181 are mounted on oppo-site ends of the cradle `179 between the side walls thereof on pivot Apins 183. The carriers 181 are generally U-shaped in cross-section and have the anged wheels mounted between the legs thereof at 4opposite ends thereof, on axles 184. The flanged wheels 16 are shown as having a central groove 185, engageable with the top of the rail and providing flanges extending along opposite sides of the top or head of the rail. An equalized mounting for the carriage 13 is thus provided on the rails 17, positively retaining the carriage from lateral movement with respect to the rails in either direction of movement of the carriage.

The `means for steering the machine laterally is :shown in FIGURES 3 and 10 `as comp-rising two aligned hydraulic jacks 187, contained within the beam 159, shown in FIGURE 4 as being 4rectangular in cross-section. rThe `hydraulic jacks 187 include cylinders 188 connected at their 'head ends lto a tongue 189 depending from acrossbeam 190 of the rear part 101 of the main frame 12. As shown `in FIGURE 3, piston rods 191 are extensible from the cylinders 188 toward `the outer ends of the `beam 159, and are pivotally connected at their outer ends to connectors 1 93 suitably secured within the beam 159 in spaced relation with respect to the ends thereof.

Thus, -upon the admission of iiuid'under pressure to the head end of one cylinder 188, the rear end portion of the main frame 12 will move laterally along the beams `159 and `173 in one direction. The direction of movement of the rear end portion of the main frame along the beams 159 `and 173 is reversed by the admission of fluid under pressure to the head end of the opposite cylinder 188. The entire main frame 12 may thus 'be pivoted laterally about the point of engagement of the ground engaging shoe 24 with the bottom of the tunnel wal-l to steer the machine laterally by the operation of either hydraulic jack 187, as previously described.

It is, of course, vunderstood that if desired, fluid under pressure may be admitted to the head end of one cylinder 188 and to the piston rod end of the opposite cylinder 188, where more force is required than could be obtained by the admission of uid under pressure to the head ends only of the cylinders 188.

The boring head 11, as shown in FIGURES 1, 2 and 4, comprises a lcentral disk or plate 195 having circumferentially vspaced boring or cutter arms 196 extending radially therefrom, with material carrying buckets 197 carried by said cutter arms and .opening in the direction of rotation of the boring head to pick-up the mined materia-l from the ground and the tunnel face, during rotation and advance feeding movement of the boring head into the working face of the tunnel. The buckets 197 have rearwardly extending and radially inwardly extending discharge chute portions 199V discharging the mined lmaterial through an upwardly opening chute portion 200.of the` boring head support portion 28 of the shield 20, terminating in discharge relation with respect to the receiving end of `a conveyor 201, extending `alongthe front part 180 of the main frame 12. The buckets 197 are constructed on principles similar to those `shown and described in application Serial No. 570,147, filed by James S. 'Robbins on March 7, 1956, `now abandoned, and are no part of the 6 present invention, so will not herein be shownor described further.

Theplate or disk 195 is shown in FIGURE 2 as having a rim 203 extending inwardly therefrom to the .chute portion 199 of the buckets 197, and about the periphery of the disk 195.

A frusto-conical plate 204 extends angularly inwardly and rearwardly from the rim 203 and terminates into a vertically extending .plate 205, having a drive gear 206 bolted or otherwise secured thereto, as shown in FIG- URES 2 `and 5. The plate 205 terminates into a sleeve 207 extending rearwardly from the disk 1915 along a hollow support shaft 209 extending forwardly from the boring head support portion 28 of the shield 20.

The boring head support portion 28 .of the shield 20 is divided into two halves to accommodate transportation of the shield from the place of manufacture to the tunnel location yand from working place to working place, as will more clearly appear as the specification proceeds.

The shield 20 includes the boring head support portion 28, forming a support for the boring head and the drive motors therefor, `and the tunnel wa'll engaging segments 23 mounted thereon and extending about the periphery thereof.

As shown in FIGURE 2, `the boring vhead support portion 28 of the Vshield 20 has a hollow interior portion 210 forming a support for a hollow shaft 209 projecting forwardly of a forward wall 211 of said shield and forming a bearing support for the sleeve 207 of the boring head. Between the vfront Wall 211 of the boring head support portion 28 of the shield 20 and the back wall 95 thereof, is an annular wall 212 spaced inwardly .by the peripheral wall 26. Radially `inwardly spaced walls 213 and 215 also connect the walls 211 and together.

The means for driving the boring head 11, as shown in FIGURES 2 and 4, includes a plurality `of motors 217 mounted on the inside of the front wall 211 and extending rearwardly therefrom. The motors 217 may be of a .type in which `the speed reducer (not shown) is contained within the motor casing and has 4a longitudinally extending shaft 219 driven from the motor through the speed reducer. Drive pinions 220 keyed or otherwise secured to lthe shafts 219 mesh with and drive the ring gear 20.6.

It may be seen from FIGURE 4, that the motors 219 and drive gears 220 extend about the ring gear 206 and are located eccentric of the center of gravity of the boring head. The boring head 11 rotates in a counters-lockwise direction about the boring head -support portion -28 of `the shield 20 when looking at FIGURE 4 :from the front thereof. The motors 217 are so positioned about the ring gear 206 as to exert a force on the boring head support `portion 28 in a clockwise direction. The weight of the eccentrically mounted motors 217, therefore, tends to counteract the torque reaction on the boring head support portion 28 and the main frame 12 and reduce the twisting torquerthereon, tending to rotate the boring head support and main frame 12 about the axis of the boring head.

Theboring head support portion 28 ofthe shield 20 has a plurality of recessed portions 221 therein, opening to the periphery of said support and extending thereabout for the full circumference thereof. The recessed 'portions 221 have bearing support blocks 222 mounted therein, forming bearing supports for thrust rollers 223, engaging a thrust ring 225 extending about the rear end portion of the boring head 11 outwardly of the plate or disk 19.5 and taking the axial thrusting loads on the boring head (FIG-

URES

2, 4 and 5). Y While one form in Iwhich the invention may be embodied is herein shown and' described, it should be understood that Various variations and modifications in the present invention may be effected without departing from the spirit and Scope of the novel concepts thereof.

The invention is claimed as follows:

1, In a rotary tunneling machine,

an elongated articulated main frame,

a rotary boring head rotatably mounted at the forward end of said main frame,

a motor on said main frame for rotatably driving said boring head,

power means for advancing said main frame and feeding said boring head into a tunnel face,

said main frame including a front frame structure and a rear frame structure,

vertical pivot means pivotally connecting said' front frame structure to said rear frame structure in a plane intersecting the longitudinal center of said main frame,

spacers adapted to be selectively connected between the adjacent ends of said frame structures on one and on both sides of said pivot means,

means selectively connecting at least one of said spacer means between the adjacent ends of said frame structures for spacing said frame structures into and out of axial alignment with respect to each other,

and guide means retaining the rear end portion of said rear frame structure from lateral movement with respect to the tunnel wall whereby said spacer means will effect the driving of a tunnel in an arcuate path when spacing said frame structures out of axial alignment with respect to each other.

2. A rotary tunneling machine in accordance with claim l,

in which the spacer means comprises spacer blocks at opposite sides of the vertical pivot of said main `frame and in which the means retaining said spacer means between said front and said rear frame structures comprise clamping plates clamped to said spacer means.

3. A rotary tunneling machine in accordance with claim l,

in which the spacer blocks have opposite faces engaging said front and rear frame structures and extend ing angularly with respect to each other.

4. In a rotary tunneling machine,

an elongated main frame,

a boring head rotatably mounted at the forward end of said main frame,

means for advancing said main frame along the tunnel wall and feeding said boring head into a tunnel face,

motor means for rotatably driving said boring head,

circumferentially spaced guide shoes slidably engageable with the tunnel wall and positioned closely adjacent said boring head,

a carriage supporting and guiding the rear end portion of said main frame and including trucks guided for movement along the tunnel wall at opposite sides of said main frame and retained from lateral movement with respect to the tunnel wall,

a transverse beam mounted on said trucks,

a laterally slidable supporting mounting for the rear end portion of said main frame on said transverse beam,

and hydraulic jack means laterally moving said main frame along said carriage.

5. In a rotary tunneling machine,

an elongated main frame,

a boring head rotatably mounted at the forward end of said main frame,

means feeding said boring head into a tunnel face,

circumferentially spaced guide shoes slidably engageable with the tunnel wall closely adjacent said boring head,

a support shoe spaced circumferentially of said guide shoes and slidably engaging the tunnel oor,

means tilting said boring head in a vertical direction about said support shoe comprising,

a carriage at the rear end of said main frame including trucks at opposite sides of said main frame and retained from lateral movement with respect to the tunnel wall,

a transverse beam supported on said trucks,

a support mounting for the rear end portion of said main `frame on said transverse beam,

the mounting of said beam on said trucks comprising hydraulic jack means operable to vertically move said transverse beam and pivot said boring head about the bottom of said support and guide shoes.

6. A rotary tunneling machine in accordance with claim 5 in which the support mounting for the rear end portion of the main frame on the transverse beam is a laterally slidable mounting and in which hydraulic jacks are provided to move the rear end portion of said main frame along said transverse beam and to retain the rear end portion of said main frame in fixed relation with respect to said transverse beam.

7. In a rotary tunneling machine, an elongated main frame,

a rotary boring head mounted at the forward end' of said main frame,

means for rotatably driving said Iboring head,

support means at the `forward end of said main frame for supporting said boring head for movement along the tunnel wall, power means for advancing said main frame along the tunnel wall and feeding said boring head into a tunnel face,

said main frame being articulated intermediate its ends and comprising front and rear frame sections connected together for movement about a vertical axis intermediate the ends of said main frame,

means adjacent the point of articulation of said main frame for retaining the front and rear sections of said main frame at various xed angular relations with respect to each other,

support means supporting the rear end portion of said main frame and retaining the rear end portion of said main frame from lateral movement with respect to the tunnel wall,

whereby the path of driving the tunnel is controlled by the angular relation of said front and rear sections of said main frame with respect to each other.

8. In a rotary tunneling machine,

an elongated main frame,

a rotary boring head mounted' in the forward end of said main frame,

means for rotatably driving said boring head,

means for advancing said main frame along the tunnel wall and feeding said boring head into the tunnel face,

support means adjacent the forward end of said main frame for supporting said boring head for movement along the tunnel wall,

guide means adjacent said boring head having slidable guiding engagement with the tunnel Wall for guiding said boring head along the tunnel wall,

rear support means for the rear end portion of said main frame,

said main frame being articulated intermediate its ends and comprising front and rear frame structures pivotally connected together for movement about a vertical axis between said guide means and said support means,

means adjacent the point of articulation of said main -frame for retaining the front and rear structures of said main frame into and out of axial alignment with respect to each other,

means guiding said rear support means for movement along the tunnel wall and retaining said rear support means from lateral movement with respect to the tunnel wall,

whereby the line of travel of said tunneling machine is dependent upon the angular relation of said front and rear frame structures with respect to each other,

and means for laterally moving the rear end portion of said main frame along said support means as selected.

9. In a rotary tunneling machine,

an elongated main frame,

a rotary boring head mounted at the forward end of said main frame,

means for rotatably driving said boring head,

means -for advancing said main frame along the tunnel wall and feeding said boring head into the tunnel face,

guide means adjacent said boring head having slidable engagement With the tunnel wall,

rear support means for the rear end portion of said main frame,

said main frame being articulated and comprising front and rear frame structures pivotally connected together for movement about a vertical axis intermediate said guide means and said 4rear support means,

spacer means at the adjacent ends of said front and rear frame structures,

spacing said frame structures into and' out of axial alignment with respect to each other,

individual trucks supporting said rear support means,

a laterally slida-ble connection between said main frame and said rear support means,

means laterally moving said main frame along said rear support means as selected,

and means supporting said support means on said trucks and vertically moving said rear support means for tilting said boring head about said front support means,

said trucks guiding the rear end portion of said main frame for movement along a xed path,

whereby the line of the tunnel may be varied by varying the angular relation between said front and said rear frame structures.

References Cited in the file of this patent UNITED STATES PATENTS 1,185,797 Hodgson June 6, 1916 1,501,093 Blower July 15, 1924 1,922,063 Vaughn Aug. 15, 1933 2,170,660 Langmyhr Aug. 22, 1939 2,694,563 Graham Nov. 16, 1954 2,764,397 Compton Sept, 25, 1956 2,766,977 Robbins Oct. 16, 1956 2,766,978 Robbins Oct. 16, 1956 2,837,325 Biedess June 3, 1958 2,839,165 Gasso June 17, 1958 2,839,281 Alspaugh et al. June 17, 1958 2,864,600 Kirkpatrick Dec. 16, 1958 2,874,936 Gonzales Feb. 24, 1959