APPARATUS FOR USE IN SUBTERRANEAN EXCAVATION
United States Patent 3650116
A multisection shield incorporates means for subterranean excavation and for removal of excavated materials, and provides for the installation of planked lining within the shield. The apparatus is employed in a system of tunnel or conduit lining wherein floor and roof planks are prepositioned, and side wall planks are thereafter wedges in place therebetween. The apparatus further includes a forward safety bonnet operated in advance of excavation, and directional control means.
US Patent References:
Rotary cutter wheel tunneling machine
Tabor - May 1968 - 3382002
Tunneling machine with power operated poling plates
Tabor - February 1967 - 3306055
Method of and apparatus for forming tunnels
Warner et al. - July 1933 - 1917170
Apparatus and method for installing pipe
Gilman - February 1934 - 1948707
Tunneling apparatus
Caputo - April 1940 - 2196100
Rotary cutter wheel tunneling machine
Tabor - May 1968 - 3382002
Tunneling machine with power operated poling plates
Tabor - February 1967 - 3306055
Method of and apparatus for forming tunnels
Warner et al. - July 1933 - 1917170
Apparatus and method for installing pipe
Gilman - February 1934 - 1948707
Tunneling apparatus
Caputo - April 1940 - 2196100
Application Number:
05/066701
Publication Date:
03/21/1972
Filing Date:
08/25/1970
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
405/146, 405/144
International Classes:
E21D9/08; E21D19/00; E21D9/06; E01G3/02
Field of Search:
61/84,85,42,43,45 299/31,33
US Patent References:
Primary Examiner:
Taylor, Dennis L.
Parent Case Data:
CROSS REFERENCE TO RELATED APPLICATION
This application relates to improvements developed in the type of excavation apparatus as shown in my prior, co-pending application Ser. No. 823,407, filed May 9, 1969, entitled METHOD AND APPARATUS FOR FORMING SUBTERRANEAN STRUCTURES, of which this application is a continuation-in-part.
Claims:
I claim
1. In an apparatus for excavation and lining of subterranean tunnels including a shield assembly having multiple sections including a forward section of rectangular configuration in cross section including a top wall, right angle side walls and a base wall, and terminating forwardly in leading edges, an inclined plate mounted on the base wall rearwardly of the leading edge of the same and including an elevated discharge end to direct material rearwardly from the open end of said forward section, and conveyor means operatively associated with the elevated discharge end of said inclined plate to further move excavated material rearwardly within said apparatus, an excavation assembly within the shield, including digging apparatus movably mounted for excavation forwardly of the shield, and means for advancing the shield comprising a jack system contained within the shield and effective to force movement of the shield in one direction, the improvement comprising:
2. The apparatus as claimed in claim 1, further comprising a direction control plate hingedly connected for pivoting about a horizontal axis to the leading edge of the base wall and extending longitudinally the full width of said forward section and means for controlling the angular position of said control plate with respect to said base to thereby control the up and down movement of said apparatus which conforms generally to the angular position of said directional control plate relative to the plane of said base wall.
3. The apparatus as claimed in claim 1, wherein said means for controlling the angular position of said guide plate comprises: a plurality of threaded shafts pivotably coupled to said control and extending upwardly therefrom, fixed retainer means extending inwardly from the side walls of said shield forward section, and adjustable lock members adjustably secured on said shafts on each side of said retainer receiving said shafts.
1. In an apparatus for excavation and lining of subterranean tunnels including a shield assembly having multiple sections including a forward section of rectangular configuration in cross section including a top wall, right angle side walls and a base wall, and terminating forwardly in leading edges, an inclined plate mounted on the base wall rearwardly of the leading edge of the same and including an elevated discharge end to direct material rearwardly from the open end of said forward section, and conveyor means operatively associated with the elevated discharge end of said inclined plate to further move excavated material rearwardly within said apparatus, an excavation assembly within the shield, including digging apparatus movably mounted for excavation forwardly of the shield, and means for advancing the shield comprising a jack system contained within the shield and effective to force movement of the shield in one direction, the improvement comprising:
2. The apparatus as claimed in claim 1, further comprising a direction control plate hingedly connected for pivoting about a horizontal axis to the leading edge of the base wall and extending longitudinally the full width of said forward section and means for controlling the angular position of said control plate with respect to said base to thereby control the up and down movement of said apparatus which conforms generally to the angular position of said directional control plate relative to the plane of said base wall.
3. The apparatus as claimed in claim 1, wherein said means for controlling the angular position of said guide plate comprises: a plurality of threaded shafts pivotably coupled to said control and extending upwardly therefrom, fixed retainer means extending inwardly from the side walls of said shield forward section, and adjustable lock members adjustably secured on said shafts on each side of said retainer receiving said shafts.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the same field of endeavor described in the aforesaid prior application, that is, to the formation of subterranean tunnels, conduits and other excavations of the type needed illustratively for sewer lines, in mining, and the like. The invention comprehends new and novel equipment for safely and speedily forming subterranean earth openings. The present improvements deal with a novel advance bonnet employed in certain types of soil formations, and to a directional control means also useful under that circumstance of use.
2. Statement of the Prior Art
The present improvements have arisen from practical employment of the apparatus shown in and described in the aforesaid prior application, which contains a statement of the most relevant known prior art.
SUMMARY OF THE INVENTION
In common with the invention of said prior application, the present apparatus relates to that category of equipment wherein a shield is forced into the tunnelling area, the shield being associated with excavation equipment and conveying means. The present apparatus provides a new and novel means for installation of lining timbers within the shield, and for advance of the shield with respect to the previously installed stand or course thereof, employing said previous stand or course as a base for the advancing mechanism. It is a basic objective of this invention to provide apparatus for the safe, rapid and economical formation and lining of subterranean tunnels, accomplished through the use of self-contained excavation, conveying and shield means, in which the tunnel lining is prepositioned within the shield. By virtue of the installation of an effective liner within the confines of the shield, there is no section of tunnelling exposed to the possibility of cave-ins, dislodgment of large rocks or the like, or other similar mishaps. Moreover, the present invention comprehends an advance overhead bonnet adapted for independent movement ahead of the shield in soil particularly subject to cave-in, such as loose sand, and the like, to further protect the operator of the apparatus.
In such soil conditions, it is also often difficult to control the direction of movement of the apparatus, particularly as to maintaining a desired level of cut. To overcome this problem, the present apparatus incorporates a hinged control plate serving to define a level control mechanism for the shield as it moves through the ground. The control plate is mounted for modification of its angle of attack during operation, if modification is necessary to maintain a desired angle, or if a change in angle is called for.
This invention comprehends a shield assembly which, when placed in an initially formed excavation, is thereafter self-advancing as formation of a tunnel progresses. In accomplishing this objective, the shield comprising leading and trailing sections, the leading section having the excavation apparatus, and the trailing section being used as an assembly area for the tunnel lining. Extensible means in the form of a group of spaced apart jacks or the like are positioned medially within the shield and have portions adapted to bear against the lining. Upon extension of these jacks, the shield assembly is advanced with respect thereto, thus providing a space for the positioning of further spans or courses thereof.
By virtue of the employment of spaced apart, individually actuable jack means, the path of movement of the shield is controllable, in normal soil conditions, thereby enabling the operator to maintain a selected course and to readily correct for deviations. The hinged control plate of this invention aids in this objective where the soil is of low resistance.
The excavation apparatus hereof, which may take numerous alternative forms and cover various locations, is preferably and ideally located on the roof section of the leading portion of the shield, immediately over a conveyance area. By this means, the excavated material is effectively discharged and the space within the shield is conserved.
Additional objects and advantages of the invention include the incorporation of a self-contained conveyor means for the removal of excavated material from within the shield during operation, the provision of a selectively inclined leading guide plate for the shield, and the provision of a movable bonnet member to protect the forward open end of the shield from the entrance of overhead material during advance.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of the apparatus as it would appear in side elevation during a tunnelling excavation;
FIG. 2 is an enlarged sectional view of the apparatus upper section as viewed from the approximate plane of line 2--2 of FIG. 1, looking in the direction of the arrows;
FIG. 3 is a sectional view on line 3--3 of FIG. 2, looking in the direction of the arrows;
FIG. 4 is a forward sectional view showing the components of the improvement, taken on line 4--4 of FIG. 3, looking in the direction of the arrows;
FIG. 5 is an enlarged perspective view showing details of the control plate hereof, partially disassembled; and
FIG. 6 is a schematic hydraulic diagram of the shield and bonnet advanced cylinders hereof.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings in more detail, and initially to FIG. 1, the invention is therein shown in a typical situation of use. The apparatus includes a shield assembly 10 made up of a forward section 12, an intermediate section 14 and a trailing section 16. The individual sections collectively form a unitary shield member which is here shown as of rectangular form, but which may assume any configuration necessary to the excavation to be made therewith.
The trailing section 16 has a top wall 18, side walls 20, 22 and a base 24. At its forward edge, each of said walls terminates in a perpendicular flange 26 with a reverted lip 28. The intermediate section in like manner has a top wall 30, base wall 32, and side walls 34, 36. The trailing edges of the last named walls have perpendicular flanges 38 which abut directly against and are fixedly secured to the flanges 26, and the flanges 38 also have reverted lips 40.
The leading section and intermediate section are interiorly divided from one another by a channel form bulkhead 42 which extends about the full interior periphery thereof. The leading section has a top wall 44, base wall 46, and side walls 48, 50.
An inclined plate 52 extends upwardly from the leading edge 54 of the base wall 46. The plate has an elevated discharge end 56, and side shield members 58 and 60 are disposed on either side of the inclined plate. The conveyor system of this apparatus is generally identified in the drawing by reference numeral 62. The conveyor may be of any desired form, but as shown here includes a frame 64 with a horizontal, longitudinally extending cross plate 66. An endless chain conveyor 68 with a series of spaced apart cross bars 70 is trained about an idler axle 72 adjacent the discharge end of the inclined plate, and about a drive sprocket driven by a motor 74 at its other end. The conveyor is mounted on one or more movable jacks 76 and is therefore of variable height.
The means 78 for excavation of material in advance of the shield is similar to that disclosed in the aforesaid application. In FIG. 2, it is to be noted that longitudinal structural members 80, 82 extend along the top wall 30 of the intermediate section between the bulkhead 42 and the flange 38. A mounting plate 84 is fixedly secured to the structural members, and carries a swivel plate 86 with arcuate slots 88 and 90 therein. Disposed in the slots are side-by-side swivel members 92, 94, and member 92 having a fixed, laterally projecting extension 96 thereon. An extensible and retractable hydraulic cylinder assembly 98 is pivotally connected to the extension 96, and to a clevice 100 on the lip 40 of the flange 38. Thus, extension and retraction of the cylinder assembly pivots the swivel member and associated components in the slots 88 and 90.
A substantially vertical boom 102 is pivotally secured between the swivel members on a cross pin 104. A second hydraulic cylinder assembly 106 is also pivoted between the swivel members, on an axle 108. Enlarged boom plates 110 and 112 are fixedly secured to the boom, and the lower end of the second cylinder is pivoted therebetween on a pivot pin 114. As shown in FIG. 3, the pin 114 may be adjustably positioned in a selected pair of several pairs of openings to modify the range of operation of the excavator. An elongated arm 116 of heavy construction is pivoted between the boom plates on a pin 118. A third hydraulic cylinder 120 of the extensible and retractable variety is pivotally connected between the plates on an axle 122, and is also pivoted, on a pin 124, between forward arm plates 126, 128 fixed to the arm adjacent its outer or distal end. A hoe, comprising a digging blade 130 and a perpendicular mounting plate 132 is fixed to the arm and is rigidified by gussets 134 and 136. It will thus be observed that movement of the cylinder assemblies 106 and 120 actuates the hoe to dig into the earth in advance of the shield, and to cause loosened material to be forced up the inclined plate 52.
As indicated above, it has been assumed for purposes of description herein that an initial tunnel excavation has been accomplished prior to the institution of use of this apparatus in its method of excavating a further tunnel and lining the same. As the shield is placed in use, and advanced a measurable distance, for example, about six feet, a lining procedure is instituted. This procedure involves initially the laying in place of a group of transverse base timbers 140 which rest on the base wall 24 of the trailing section 16 of the shield.
A pair of elevator assemblies 142, best shown in FIG. 3, are employed next in the method of installation. These assemblies 142, which are identical to one another except as to positioning, are each mounted on a vertical channel member 144 in such manner and location that an assembly 142 is provided at each side of the shield. Fixed to the channel 144 is an outer channel 146 having a vertical slot 148 extending from substantially its mid-section length to its top. A boss 150 is provided at the base end of the outer channel, and a hydraulic cylinder 152 is connected thereto. The cylinder has an extensible and retractable rod 154, and is of course supplied with suitable supply lines leading to a remote control means. The rod 154 has a clevis 156 on its outer end on which an elongated arm 158 is mounted. The arm 158 has a rectangular block 160 at one end thereof which is dimensioned to be slidable within the outer channel 146, but is too great in size to pass through the slot 148. The arm 158 extends through the slot, whereby upon extension and retraction of the rod 154, the arm is raised and lowered. The control means for the elevation assembly is preferably arranged for simultaneous extension and retraction of each assembly.
As a second step in the method hereof, a group of roof timbers or rafters 162, each having slotted lower corners (not shown) are placed on the arms 158 and elevated into position above the previously placed base timbers 140.
With the roof timbers 162 elevated to a position in which they bear against the top wall 18 of the trailing shield section, and the base timbers in place therebetween, side timbers 164, 166 are forced into position. The side timbers are first positioned angularly in opposite pairs, with their upper ends being located in the slotted ends of the roof timbers. Suitable tools, such as portable hydraulic cylinders, are then employed to substantially simultaneously wedge the base ends of the side timbers into place. This fixedly engages the side timbers between the base and roof timbers, and the timbers are, of course, dimensioned for an extremely rigid connection.
The result of completion of the aforesaid process of timber placement results in the formation of tunnel lining or a completed conduit, up to a final course or stand of timbers disposed within the trailing shield section and indicated in the drawing at S. This final course of timbers co-qcts with the invention apparatus in providing means for advance of the shield. At convenient peripherally spaced positions, a series of push cylinders or jacks 168 are fixed in brackets 170 on the respective walls of the intermediate section of the shield. It will be observed in the drawing that these may be, in the rectangular form of the invention herein shown, at the four corners of the device, with a center thrust cylinder positioned on the base. This arrangement is variable with the selected shape of the shield. Each of said cylinders has an extensible and retractable rod 172 associated therewith and extended through suitable openings in the abutting flanges of the intermediate and trailing sections of the shield. Each of said rods has an abutment collar 174 which is engageable against the course S. The lining is immovable due to its manner of formation and also due to the fact that it is anchored at its terminal end by suitable jack means or otherwise. Joint extension of all of the rods 172 therefore results in straight linear movement of the shield forwardly into the earth. If one or more of the rods is not actuated with the others, the direction of movement is altered, thereby permitting a steering or course alteration in the movement of the shield.
The foregoing is substantially comprehensive of the invention herein disclosed, as well as that shown in the aforesaid co-pending application. In order to maintain a desired angle of approach into the material being excavated, the present invention includes means for control of the forward bottom edge of the shield leading section. Referring to FIGS. 3 and 5 of the drawings, it will there be observed that a plurality of spaced apart hinge sleeves 200 are fixedly secured on the leading edge 54 of the base wall 46 of the leading section. A guide plate 202 with a sharp forward edge 204 extends fully across the leading edge, and has a series of spaced hinged sleeves 206 which interfit in piano hinge fashion with the sleeves 200. An elongated pintle 208 extends through the aligned sleeves, whereby the guide plate is hingedly mounted on the leading edge of the base wall 46. Adjacent the ends of the guide plate, lift eyes 210, 212 project upwardly therefrom. Elongated, threaded shafts 214, 216, each having a ring 218, 220, are retained by the respective lift eyes, the shafts projecting upwardly through retainers 222, 224 on the side walls 50 and 48. Lock nuts 226, 228 are adjustably secured on each of the shafts, and may be rotated in order to vertically move the shafts with respect to the retainers. Lowering of the shafts results in downward pivoting of the guide plate to induce, in turn, a down angle on the travel of the shield. Conversely, raising of the shafts results in an upturned travel of the shield.
To overcome further the danger of material falling back into the shield during excavation, the present invention provides a shield upper bonnet assembly, designated generally by reference numeral 300 in the drawing. The bonnet includes a roof plate 302 overlying the top wall of the shield, and side plates 304, 306 depending therefrom over the upper portion of the shield side walls 48 and 50. The roof plate 302 includes a leading edge 308, and a top angle plate 310 extends inwardly therefrom. The leading edges of the side plates 304 and 306 are preferably angled inwardly, and each has a side angle plate 312, 314. Side push elements 316, 318 are disposed at the junctures of the top bonnet plate 310 with the respective side angle plates 312 and 314. The push elements each includes a horizontal member 320 and a vertical member 322. These members carry fixed guide lugs 324 and 326 which ride in longitudinal slots 328, 330, respectively, formed in the shield top wall 44 and the side walls 48 and 50. A vertical abutment 332 depends from each of the horizontal members 320 and carries an eye member 334. Pivotally secured to the eye member is a clevis 336 comprising the outer end of an extensible rod 338 of a cylinder assembly 340. The cylinders 340 are retained in brackets 342 in the intermediate section of the shield.
Referring to FIG. 6 of the drawing, a typical hydraulic layout for shield and shield bonnet advance in the environment of this invention is therein shown and described. With the shield propulsion cylinders 168 ready for advance, the shield bonnet cylinders are in neutral position, permitting them to retract upon forward movement of the main shield. Thereafter, when planking is completed to the extent of the shield advance, and excavation ready to begin preparatory to a further advance, the bonnet is first advanced, thus protecting the hoe operator from overhead cave-in of material.
1. Field of the Invention
This invention relates generally to the same field of endeavor described in the aforesaid prior application, that is, to the formation of subterranean tunnels, conduits and other excavations of the type needed illustratively for sewer lines, in mining, and the like. The invention comprehends new and novel equipment for safely and speedily forming subterranean earth openings. The present improvements deal with a novel advance bonnet employed in certain types of soil formations, and to a directional control means also useful under that circumstance of use.
2. Statement of the Prior Art
The present improvements have arisen from practical employment of the apparatus shown in and described in the aforesaid prior application, which contains a statement of the most relevant known prior art.
SUMMARY OF THE INVENTION
In common with the invention of said prior application, the present apparatus relates to that category of equipment wherein a shield is forced into the tunnelling area, the shield being associated with excavation equipment and conveying means. The present apparatus provides a new and novel means for installation of lining timbers within the shield, and for advance of the shield with respect to the previously installed stand or course thereof, employing said previous stand or course as a base for the advancing mechanism. It is a basic objective of this invention to provide apparatus for the safe, rapid and economical formation and lining of subterranean tunnels, accomplished through the use of self-contained excavation, conveying and shield means, in which the tunnel lining is prepositioned within the shield. By virtue of the installation of an effective liner within the confines of the shield, there is no section of tunnelling exposed to the possibility of cave-ins, dislodgment of large rocks or the like, or other similar mishaps. Moreover, the present invention comprehends an advance overhead bonnet adapted for independent movement ahead of the shield in soil particularly subject to cave-in, such as loose sand, and the like, to further protect the operator of the apparatus.
In such soil conditions, it is also often difficult to control the direction of movement of the apparatus, particularly as to maintaining a desired level of cut. To overcome this problem, the present apparatus incorporates a hinged control plate serving to define a level control mechanism for the shield as it moves through the ground. The control plate is mounted for modification of its angle of attack during operation, if modification is necessary to maintain a desired angle, or if a change in angle is called for.
This invention comprehends a shield assembly which, when placed in an initially formed excavation, is thereafter self-advancing as formation of a tunnel progresses. In accomplishing this objective, the shield comprising leading and trailing sections, the leading section having the excavation apparatus, and the trailing section being used as an assembly area for the tunnel lining. Extensible means in the form of a group of spaced apart jacks or the like are positioned medially within the shield and have portions adapted to bear against the lining. Upon extension of these jacks, the shield assembly is advanced with respect thereto, thus providing a space for the positioning of further spans or courses thereof.
By virtue of the employment of spaced apart, individually actuable jack means, the path of movement of the shield is controllable, in normal soil conditions, thereby enabling the operator to maintain a selected course and to readily correct for deviations. The hinged control plate of this invention aids in this objective where the soil is of low resistance.
The excavation apparatus hereof, which may take numerous alternative forms and cover various locations, is preferably and ideally located on the roof section of the leading portion of the shield, immediately over a conveyance area. By this means, the excavated material is effectively discharged and the space within the shield is conserved.
Additional objects and advantages of the invention include the incorporation of a self-contained conveyor means for the removal of excavated material from within the shield during operation, the provision of a selectively inclined leading guide plate for the shield, and the provision of a movable bonnet member to protect the forward open end of the shield from the entrance of overhead material during advance.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of the apparatus as it would appear in side elevation during a tunnelling excavation;
FIG. 2 is an enlarged sectional view of the apparatus upper section as viewed from the approximate plane of line 2--2 of FIG. 1, looking in the direction of the arrows;
FIG. 3 is a sectional view on line 3--3 of FIG. 2, looking in the direction of the arrows;
FIG. 4 is a forward sectional view showing the components of the improvement, taken on line 4--4 of FIG. 3, looking in the direction of the arrows;
FIG. 5 is an enlarged perspective view showing details of the control plate hereof, partially disassembled; and
FIG. 6 is a schematic hydraulic diagram of the shield and bonnet advanced cylinders hereof.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings in more detail, and initially to FIG. 1, the invention is therein shown in a typical situation of use. The apparatus includes a shield assembly 10 made up of a forward section 12, an intermediate section 14 and a trailing section 16. The individual sections collectively form a unitary shield member which is here shown as of rectangular form, but which may assume any configuration necessary to the excavation to be made therewith.
The trailing section 16 has a top wall 18, side walls 20, 22 and a base 24. At its forward edge, each of said walls terminates in a perpendicular flange 26 with a reverted lip 28. The intermediate section in like manner has a top wall 30, base wall 32, and side walls 34, 36. The trailing edges of the last named walls have perpendicular flanges 38 which abut directly against and are fixedly secured to the flanges 26, and the flanges 38 also have reverted lips 40.
The leading section and intermediate section are interiorly divided from one another by a channel form bulkhead 42 which extends about the full interior periphery thereof. The leading section has a top wall 44, base wall 46, and side walls 48, 50.
An inclined plate 52 extends upwardly from the leading edge 54 of the base wall 46. The plate has an elevated discharge end 56, and side shield members 58 and 60 are disposed on either side of the inclined plate. The conveyor system of this apparatus is generally identified in the drawing by reference numeral 62. The conveyor may be of any desired form, but as shown here includes a frame 64 with a horizontal, longitudinally extending cross plate 66. An endless chain conveyor 68 with a series of spaced apart cross bars 70 is trained about an idler axle 72 adjacent the discharge end of the inclined plate, and about a drive sprocket driven by a motor 74 at its other end. The conveyor is mounted on one or more movable jacks 76 and is therefore of variable height.
The means 78 for excavation of material in advance of the shield is similar to that disclosed in the aforesaid application. In FIG. 2, it is to be noted that longitudinal structural members 80, 82 extend along the top wall 30 of the intermediate section between the bulkhead 42 and the flange 38. A mounting plate 84 is fixedly secured to the structural members, and carries a swivel plate 86 with arcuate slots 88 and 90 therein. Disposed in the slots are side-by-side swivel members 92, 94, and member 92 having a fixed, laterally projecting extension 96 thereon. An extensible and retractable hydraulic cylinder assembly 98 is pivotally connected to the extension 96, and to a clevice 100 on the lip 40 of the flange 38. Thus, extension and retraction of the cylinder assembly pivots the swivel member and associated components in the slots 88 and 90.
A substantially vertical boom 102 is pivotally secured between the swivel members on a cross pin 104. A second hydraulic cylinder assembly 106 is also pivoted between the swivel members, on an axle 108. Enlarged boom plates 110 and 112 are fixedly secured to the boom, and the lower end of the second cylinder is pivoted therebetween on a pivot pin 114. As shown in FIG. 3, the pin 114 may be adjustably positioned in a selected pair of several pairs of openings to modify the range of operation of the excavator. An elongated arm 116 of heavy construction is pivoted between the boom plates on a pin 118. A third hydraulic cylinder 120 of the extensible and retractable variety is pivotally connected between the plates on an axle 122, and is also pivoted, on a pin 124, between forward arm plates 126, 128 fixed to the arm adjacent its outer or distal end. A hoe, comprising a digging blade 130 and a perpendicular mounting plate 132 is fixed to the arm and is rigidified by gussets 134 and 136. It will thus be observed that movement of the cylinder assemblies 106 and 120 actuates the hoe to dig into the earth in advance of the shield, and to cause loosened material to be forced up the inclined plate 52.
As indicated above, it has been assumed for purposes of description herein that an initial tunnel excavation has been accomplished prior to the institution of use of this apparatus in its method of excavating a further tunnel and lining the same. As the shield is placed in use, and advanced a measurable distance, for example, about six feet, a lining procedure is instituted. This procedure involves initially the laying in place of a group of transverse base timbers 140 which rest on the base wall 24 of the trailing section 16 of the shield.
A pair of elevator assemblies 142, best shown in FIG. 3, are employed next in the method of installation. These assemblies 142, which are identical to one another except as to positioning, are each mounted on a vertical channel member 144 in such manner and location that an assembly 142 is provided at each side of the shield. Fixed to the channel 144 is an outer channel 146 having a vertical slot 148 extending from substantially its mid-section length to its top. A boss 150 is provided at the base end of the outer channel, and a hydraulic cylinder 152 is connected thereto. The cylinder has an extensible and retractable rod 154, and is of course supplied with suitable supply lines leading to a remote control means. The rod 154 has a clevis 156 on its outer end on which an elongated arm 158 is mounted. The arm 158 has a rectangular block 160 at one end thereof which is dimensioned to be slidable within the outer channel 146, but is too great in size to pass through the slot 148. The arm 158 extends through the slot, whereby upon extension and retraction of the rod 154, the arm is raised and lowered. The control means for the elevation assembly is preferably arranged for simultaneous extension and retraction of each assembly.
As a second step in the method hereof, a group of roof timbers or rafters 162, each having slotted lower corners (not shown) are placed on the arms 158 and elevated into position above the previously placed base timbers 140.
With the roof timbers 162 elevated to a position in which they bear against the top wall 18 of the trailing shield section, and the base timbers in place therebetween, side timbers 164, 166 are forced into position. The side timbers are first positioned angularly in opposite pairs, with their upper ends being located in the slotted ends of the roof timbers. Suitable tools, such as portable hydraulic cylinders, are then employed to substantially simultaneously wedge the base ends of the side timbers into place. This fixedly engages the side timbers between the base and roof timbers, and the timbers are, of course, dimensioned for an extremely rigid connection.
The result of completion of the aforesaid process of timber placement results in the formation of tunnel lining or a completed conduit, up to a final course or stand of timbers disposed within the trailing shield section and indicated in the drawing at S. This final course of timbers co-qcts with the invention apparatus in providing means for advance of the shield. At convenient peripherally spaced positions, a series of push cylinders or jacks 168 are fixed in brackets 170 on the respective walls of the intermediate section of the shield. It will be observed in the drawing that these may be, in the rectangular form of the invention herein shown, at the four corners of the device, with a center thrust cylinder positioned on the base. This arrangement is variable with the selected shape of the shield. Each of said cylinders has an extensible and retractable rod 172 associated therewith and extended through suitable openings in the abutting flanges of the intermediate and trailing sections of the shield. Each of said rods has an abutment collar 174 which is engageable against the course S. The lining is immovable due to its manner of formation and also due to the fact that it is anchored at its terminal end by suitable jack means or otherwise. Joint extension of all of the rods 172 therefore results in straight linear movement of the shield forwardly into the earth. If one or more of the rods is not actuated with the others, the direction of movement is altered, thereby permitting a steering or course alteration in the movement of the shield.
The foregoing is substantially comprehensive of the invention herein disclosed, as well as that shown in the aforesaid co-pending application. In order to maintain a desired angle of approach into the material being excavated, the present invention includes means for control of the forward bottom edge of the shield leading section. Referring to FIGS. 3 and 5 of the drawings, it will there be observed that a plurality of spaced apart hinge sleeves 200 are fixedly secured on the leading edge 54 of the base wall 46 of the leading section. A guide plate 202 with a sharp forward edge 204 extends fully across the leading edge, and has a series of spaced hinged sleeves 206 which interfit in piano hinge fashion with the sleeves 200. An elongated pintle 208 extends through the aligned sleeves, whereby the guide plate is hingedly mounted on the leading edge of the base wall 46. Adjacent the ends of the guide plate, lift eyes 210, 212 project upwardly therefrom. Elongated, threaded shafts 214, 216, each having a ring 218, 220, are retained by the respective lift eyes, the shafts projecting upwardly through retainers 222, 224 on the side walls 50 and 48. Lock nuts 226, 228 are adjustably secured on each of the shafts, and may be rotated in order to vertically move the shafts with respect to the retainers. Lowering of the shafts results in downward pivoting of the guide plate to induce, in turn, a down angle on the travel of the shield. Conversely, raising of the shafts results in an upturned travel of the shield.
To overcome further the danger of material falling back into the shield during excavation, the present invention provides a shield upper bonnet assembly, designated generally by reference numeral 300 in the drawing. The bonnet includes a roof plate 302 overlying the top wall of the shield, and side plates 304, 306 depending therefrom over the upper portion of the shield side walls 48 and 50. The roof plate 302 includes a leading edge 308, and a top angle plate 310 extends inwardly therefrom. The leading edges of the side plates 304 and 306 are preferably angled inwardly, and each has a side angle plate 312, 314. Side push elements 316, 318 are disposed at the junctures of the top bonnet plate 310 with the respective side angle plates 312 and 314. The push elements each includes a horizontal member 320 and a vertical member 322. These members carry fixed guide lugs 324 and 326 which ride in longitudinal slots 328, 330, respectively, formed in the shield top wall 44 and the side walls 48 and 50. A vertical abutment 332 depends from each of the horizontal members 320 and carries an eye member 334. Pivotally secured to the eye member is a clevis 336 comprising the outer end of an extensible rod 338 of a cylinder assembly 340. The cylinders 340 are retained in brackets 342 in the intermediate section of the shield.
Referring to FIG. 6 of the drawing, a typical hydraulic layout for shield and shield bonnet advance in the environment of this invention is therein shown and described. With the shield propulsion cylinders 168 ready for advance, the shield bonnet cylinders are in neutral position, permitting them to retract upon forward movement of the main shield. Thereafter, when planking is completed to the extent of the shield advance, and excavation ready to begin preparatory to a further advance, the bonnet is first advanced, thus protecting the hoe operator from overhead cave-in of material.