DEVICE FOR TUNNELING
United States Patent 3708021
A device for tunneling comprising driving a plurality of interlocking staves into the earth about a chosen circumference, by resonantly sonically vibrating the staves as they are being driven. After a circumference of the staves are formed the core of earth therebetween is removed to form the tunnel.
US Patent References:
Coupler for coupling a pile member to a pile driver
Muller - August 1963 - 3100382
Sonic method and apparatus for installing complex structures
Bodine, Jr. - April 1968 - 3380541
/1075027.html
Ebbley - October 1913 - 1075027
Coupler for coupling a pile member to a pile driver
Muller - August 1963 - 3100382
Sonic method and apparatus for installing complex structures
Bodine, Jr. - April 1968 - 3380541
/1075027.html
Ebbley - October 1913 - 1075027
Application Number:
05/105482
Publication Date:
01/02/1973
Filing Date:
01/11/1971
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
173/52
International Classes:
E21D9/00; E21D9/10; E01G5/14
Field of Search:
175/19,55,56 173/49,52 299/31,33
Primary Examiner:
Purser, Ernest R.
Parent Case Data:
This application is a division of my application Ser. No. 749,686 filed Aug. 2, 1968.
Claims:
I claim
1. A device for driving tunneling staves into the earth comprising:
2. The device of claim 1 wherein said oscillators are oriented relative to said staves so as to impart vibrational energy to said staves along the longitudinal axes thereof.
3. The device of claim 1 wherein said means for driving said oscillators comprises a motor and shaft means for coupling the output of said motor to each of said oscillators.
4. The device of claim 1 wherein said clamp means comprises a pair of jaws and hydraulic drive means for driving said jaws into engagement with the ends of said staves.
1. A device for driving tunneling staves into the earth comprising:
2. The device of claim 1 wherein said oscillators are oriented relative to said staves so as to impart vibrational energy to said staves along the longitudinal axes thereof.
3. The device of claim 1 wherein said means for driving said oscillators comprises a motor and shaft means for coupling the output of said motor to each of said oscillators.
4. The device of claim 1 wherein said clamp means comprises a pair of jaws and hydraulic drive means for driving said jaws into engagement with the ends of said staves.
Description:
Prior to the herein invention tunnels were normally formed by dynamiting mountains or the like to be tunneled. There are several disadvantages to that approach. Firstly, of course, dynamite is extremely dangerous to handle. Secondly, the tunneling is almost completely uncontrolled with often a much larger area being blasted or affected than needed or desired. Once the area has been effectively blasted with the dynamite, an extensive removal process for the large boulders and earth involved is required. During and after this process there is still a problem of cave-in prior to the insertion of the reinforcing tubes or whatever is utilized to form the basic reinforced structure of the tunnel. Generally, the area between the reinforced tunnel elements and the larger diameter blasted is filled to provide a solid support for the reinforcing elements. This is obviously a time-consuming, and expensive and complicated process. To date no one has been able to successfully tunnel a hole in difficult formation to the exact desired dimensions required.
The herein invention presents a new concept in tunneling. This invention utilizes in one typical embodiment a device for inserting into the earth a pair of diametrically opposed staves which, for example, could be tubular elements through which soil treatment material may be introduced. On one side of each stave is a tongue and the other side is provided with a grooved extension. The device of this invention can be mounted on the front of a tractor or other suitable device such as a car that can move on a rail bed. The staves are attached to a large support structure which in turn is connected to the tractor or other implement. In one embodiment, the tractor is moved forward during sonic activation, forcing the staves into the ground. While the tractor is moving forward, the staves are individually resonantly sonically vibrated. This substantially loosens the dirt surrounding them, easing the penetration into the ground. The structure that supports the two staves is successively rotated about its center axis, placing additional staves by side about the circumference of the structure. Due to the tongue and groove construction, a tightly sealed circular tube is formed from the plurality of staves. The center earth core is then removed, and additional series of such staves is continued for the length of the tunnel. In a second embodiment of the invention, the tractor or implement containing the power equipment remains stationary while the support structure for the staves is moved forward along a center guide rod that additionally engages the earth. This center guide rod serves to additionally assure accurate centering of the support structure, resulting in precise positioning of the stave elements.
It is believed that the invention will be better understood from the following detailed description and drawings in which:
FIG. 1 is a pictorial representation of the device of this invention mounted on a suitable tractor;
FIG. 2 is a sectional view taken along lines 2--2 of FIG. 1;
FIG. 3 is a front view taken along lines 3--3 of FIG. 1;
FIG. 4 is a sectional view taken along lines 4--4 of FIG. 2;
FIG. 5 is a sectional view taken along lines 5--5 of FIG. 2;
FIG. 6 is a top plan view taken along line 6--6 of FIG. 5;
FIG. 7 is an enlarged cross-sectional view of the staves taken along lines 4--4 of FIG. 3;
FIG. 8 is a pictorial representation of a second embodiment of this invention;
FIG. 9 is a pictorial representation of the second embodiment of this invention, disclosing the removal of staves from a storage car;
FIG. 10 is a partially sectioned view taken along lines 7--7 of FIG. 5;
FIG. 11a is a pictorial view of the second embodiment of this invention wherein the staves are in a starting position;
FIG. 11b is a pictorial representation of the second embodiment of this invention wherein the staves are in a final inserted position; and
FIG. 12 is an enlarged cross-sectional view of a plurality of flat interlocked slightly curved staves.
It has been found most helpful in analyzing the operation of the device of this invention to analogize the acoustically vibrating circuit involved to an equivalent electrical circuit. This sort of approach to analysis is well known to those skilled in the art and is described, for example, in Chapter 2 of "Sonics" by Hueter and Bolt, published in 1955 by John Wiley and Sons. In making such an analogy, force F is equated with electrical voltage E, velocity of vibration u is equated with electrical current i, mechanical compliance C m is equated with electrical capacitance C e , mass M is equated with electrical inductance L, mechanical resistance (friction) R m is equated with electrical resistance R, and mechanical impedance Z m is equated with electrical impedance Z e .
Thus, it can be shown that if a member is elastically vibrated by means of an acoustical sinusoidal force F o sinωt (ω being equal to 2 π times the frequency of vibration), that
Where ωM is equal to 1/ω C m , a resonant condition exists, and the effective mechanical impedance Z m is equal to the mechanical resistance R m , the reactive impedance components ωM and 1/ω C m cancelling each other out. Under such a resonant condition, velocity of vibration u is at a maximum, power factor is unity, and energy is most efficiently delivered to a load to which the resonant system may be coupled.
It is important to note the significance of the attainment of high acoustical "Q" in the resonant system being driven, to increase the efficiency of the vibration thereof and to provide a maximum amount of energy for the grinding operation. As for an equivalent electrical circuit, the "Q" of an acoustical vibration circuit is defined as the sharpness of, resonance thereof, and is indicative of the ratio of the energy stored in each vibration cycle to the energy used in each such cycle. "Q" is mathematically equated to the ratio between ωM and R m . Thus the effective "Q" of the vibrating circuit can be maximized to make for highly efficient high-amplitude vibration by minimizing the effect of resistance in such circuit.
Of significance in the implementation of the method and devices of this invention is the high acceleration of the components of the elastic resonant system that can be achieved at sonic frequencies. The acceleration of a vibrating mass is a function of the square of the frequency of the drive signal times the amplitude of vibration. This can be shown as follows:
The instantaneous displacement y of a sinusoidally vibrating mass can be represented by the following equation:
y = Ycosωt 2.
where Y is the maximum displacement in the vibration cycle and is equal to 2πf, f being the frequency of vibration.
The acceleration a of the mass can be obtained by differentiating equation (2) twice, as follows:
a = (d 2 y/dt 2 ) = -Yω 2 cos(ωt) 3.
The acceleration a thus is a function of Y times (2πf) 2 . At resonance, Y is at a maximum and thus even at moderately high sonic frequencies, very high accelerations are achieved making for correspondingly high vibrational forces at the grinding interfaces.
In considering the significance of the parameters described in connection with equation (1), it should be kept in mind that the total effective resistance, mass, and compliance in the acoustical vibration circuit are represented in the equation and that these parameters may be distributed throughout the system rather than being lumped in any one component or portion thereof.
It is also to be noted that an orbiting-mass oscillator may be utilized in the device of the invention that automatically adjusts its output frequency to maintain resonance with changes in the characteristics of the load. Thus, in the face of changes in the effective mass and compliance presented by the load, the system automatically is maintained in optimum resonant operation by virtue of the "lock-in" characteristics of applicant's unique orbiting-mass oscillator. The orbiting-mass oscillator automatically changes not only its frequency but its phase angle and therefore its power factor with changes in the resistive impedance load to assure optimum efficiency of operation at all times.
Turning now to the drawings, FIGS. 1 and 2 particularly, there is seen a tractor bogie device 11 having a support structure 13 to carry the device 15 of this invention. Mounted on the tractor bogie 11 is a large power unit 16. A motor in housing 17 is attached to the front of the power unit 16. Rigidly affixed to the housing 17 and extending forward therefrom is an inner support cylinder 19. Two horizontal channel beams 20, one above and one below the inner cylinder 19, serve to support it relative to the support structure 13. Mounted in a turning engagement with inner cylinder 19 is an outer cylinder 21, which is provided with a gear ring 23 about its end adjacent the tractor. The gear 23 engages a small pinion gear 24 which is connected to a motor 25 so as to controllably rotate the cylinder 21 about the inner cylinder 19. The outer cylinder 21 has rigidly affixed thereto a third cylinder 22. A large frame structure 26 and 27 extends radially from the third cylinder 22. The cylinder 22 serves to absorb the load from the frame structure 26 and 27 rather than have it placed on the rotatable cylinder 21. The frame structure 26 has in combination two radially extending sets of beams 27. Each set 27 of beams is connected to two arms 28 separated from each other by cross-plates 29. Additionally, the outer cylinder 22 has welded thereto two circumferential U-shaped rings 30. Attached to the rings 30 are cross-members 31 which rigidly support arms 28.
The frame structure 26 additionally serves to hold two orbiting-mass oscillators 32 180° apart at the outer extremity. The orbiting-mass oscillators 32 can be of a type shown, for example, in FIG. 21 of U.S. Pat. No. 2,960,314. The oscillators 32 are driven from motor 17 which rotates shaft 33 located concentrically within inner cylinder 19 and is supported therefrom through support structures 35 and bearings 37. Shaft 33 rotates gear 39 located on the end thereof. In turn gear 39 engages beveled step-up gears 41, which impart rotation to flexible shafts 43. Shafts 43 in turn are supported by bearings 45 mounted on plates 29, and drive oscillators 32.
The oscillator 32 is affixed to a hydraulic clamp 47 which in turn holds the stave 49 to be driven into the earth. Disposed behind the oscillator 32 and affixed to the frame structure 26 through a mounting bracket 51 is a pneumatic or hydraulic spring device 53. The oscillator 32 vibrates essentially in the direction of the arrow 55 which corresponds to the axis of the stave 49. Thus, the oscillator must be free to move between the bracket 51 and an outer bracket 57, which is further secured to the spring device 53.
Considering now FIG. 4 together with FIG. 2, it can be seen that plate 51 is provided with a slotted aperture 59 to allow for the vibratory movement of oscillator 32 and attached flexible shaft 43. A rod 61 is affixed at one end to the oscillator 32 and at the other end to a movable piston 63, disposed within the housing of the spring device 53. An inlet line 65 can conduct an elastic pressure fluid such as either air or oil to a cavity 67 behind the piston 63 so as to maintain bias force to cushion the vibratory effect of the oscillator.
Turning now to FIGS. 5 and 6 there is seen an hydraulic clamp arrangement 47 utilized to hold the stave elements 49. A pair of jaws 71 are pivotally connected to a base member 73. The base member 73 is in turn connected to a piston element 75 which moves in an area 77 of a housing 79. The walls of the housing are tapered at 81 along the outer surface of the jaws 71 so as to force them into tight contact with the stave element 49 in a close position as shown in FIG. 5. An outer housing 83 surrounds the inner housing 79. In order to appreciate how the jaws work, it must be understood that the stave element 49 is relatively stationary due to its weight and also due to its fixation to the stave elements that are previously in the ground. Thus, when hydraulic fluid is brought into line 85 and exits from line 87, the inner housing 79 will move relative to the outer housing 83 to the dotted position shown, allowing the jaws to disengage themselves from the stave 49. Virtually any type of hydraulic jaw is suitable for the herein application and does not form a part of this invention. The jaw shown in FIGS. 5 and 6 is merely illustrative of one type that could be utilized for holding the staves so that they can receive the vibratory energy from the oscillators utilized.
FIG. 7 is an enlarged view of a plurality of cylindrical staves 49 showing the interlocking arrangement. As seen, each stave is provided with a grooved extension 91 on one side and a tongue portion 93 oppositely disposed so that they can fit into an interlocking arrangement as shown.
The resonant vibratory energy imparted to the staves by the resonant frequency oscillators 32 during driving into the earth serves to penetrate the earth, and also to reduce the frictional resistance between the adjacent members so that a relatively tight-fitting tongue and groove connection can be achieved as shown in the figure.
In the operation of the device as shown in FIGS. 1-6, a first complete circle of staves is resonantly driven into the earth to their entire length. New staves are then welded onto the exposed end of the staves driven into the ground, and the new staves are subsequently driven to their entire length, thus forcing the original staves further into the earth. This procedure continues forming one circle after another of staves welded onto each other to the desired final depth of the tunnel. In this arrangement, the device 15 for driving the staves never travels more than the length of the staves and does not generally enter the cavity formed, but remains outside driving the series of staves as indicated.
FIGS. 8-11b disclose a device for driving staves into the earth for tunneling in the manner previously described. However, the operation of the device differs from the one shown in the previous figures in that it continually advances through the tunnel, driving a series of successive staves not axially affixed to each other. The device in FIGS. 8-11b is shown schematically since it utilizes essentially the same features of the device shown in the other drawings.
Turning now to FIGS. 8-10, the device of the second embodiment is shown schematically to depict the novel approach for placement of the staves in a successive telescoping fashion into the ground. The staves in this embodiment will have the flat slightly curved configuration as shown in FIG. 12. The staves 101 as seen in FIG. 8 are successively placed in the ground 103 in the aforementioned telescoping fashion, such that each series of staves slightly overlaps the other. The circumference of the tunnel 105 will pass through the center point 107 of each series of staves. Thus, the tunnel will have nearly a constant diameter. To accomplish this, the staves must be placed at a slight angle as shown in FIG. 8.
After a series of staves is placed into the ground in a complete circumference, the ground is removed and a second series is then inserted. This process is continually repeated until the tunnel is achieved. To accomplish this, the apparatus 109 of this embodiment comprises a tractor vehicle 111 that can move on a bed 113 laid in the formed tunnel or on rails, as desired. A guide rod 115 passes through the vehicle 111 and engages the earth at its front pointed end 117. The guide rod 115 has four racks 118 equidistantly disposed on its outer perimeter. As particularly seen in FIG. 8, the vertically disposed racke engage motor driven gears 120 located within the tractor device 111, and serve to move the tractor device relative to the guide rod 115. Before the staves are placed, the guide rod 115 is accurately centered in the tunnel and firmly engages the earth.
Mounted on the guide rod 115 in front of the tractor device 111 are two essentially identical stave support units 121 and 123, respectively, which separately move on the horizontally disposed racks by pairs of drive motors 125 and 127 located therein. As particularly seen in FIG. 10, the front unit 121 actually has a pair of opposite drive motors 125 for engaging the horizontal racks. The motors 127 in the rear unit 123 are also similarly disposed.
Each movable stave support unit 121 and 123, respectively, has a pair of oppositely disposed extendable arms 129. The arms can be pneumatically or hydraulically operated through lines 131 and 133 respectively, which in turn are connected to reel devices 135 that automatically retract the lines when the devices 121 and 123 are adjacent the tractor. In the forward device 121, the extendable arms 129 thereon pivotally engage two pneumatically operated clamping jaws 137 which can be of a construction similar to that shown in FIG. 5. The arms 129 of the rear unit 123 pivotally engage units 139 which are similar to the embodiment shown in FIG. 2, for example, in that they combine a pneumatic jaw, an oscillator and pneumatic spring in essentially the same arrangement that is shown in FIG. 2.
For simplicity, not all of the lines to direct the hydraulic fluid, or air in case of pneumatic operation, are shown in the figures. It should be understood that additional reels and lines are obviously required in order to operate all of the arms as well as the oscillator and pneumatic jaws. To operate the device of this embodiment, the tractor element 111 is moved to adjacent the rear of the center guide rod 115 as seen in FIG. 9. The jaws 137 of the movable front unit 121 pick up two stave elements 101 from a storage can 138, as seen, carrying them toward the front of the guide rod 115 to engage the earth, as seen in FIG. 11a. The arms 129 of the front movable unit 121 are extended as shown in FIG. 11a such that the elements 101 are brought in contact with the previously inserted staves. The arms 129 of the rear movable unit 123 extend such that the jaws contained in the outer units 139 enclose the rear end of the stave elements 101. The tractor 111 remains static on the bed 113, while the drive motors 127 in the rear unit 123 move the staves forward into the earth during the operation of the oscillators contained in the end units 139 to a final position shown in FIG. 11b.
After two oppositely disposed stave elements 101 are inserted, as seen in FIG. 11b, the entire center rod 115 together with the devices 121 and 123 is rotated to provide adjacent staves. This rotation can be accomplished as seen in FIG. 8 by the use of a motor 141 driving a gear 143 located on the tractor device 111. A large ring gear 145 encloses the motors 120 and is affixed thereto. When the motor 141 is actuated, ring gear 145 rotates the motors 120 which are locked to the back portion of the center member 115. This in turn causes the rotation of the entire element within the tractor 111.
Turning to FIG. 12, there is seen a cross-section of typical stave elements 101. As can be seen, the elements are flat and slightly curved, having a grooved portion 147 on one side and a tongue 149 on the other, so as to effect the arrangement shown of interlocked staves.
The herein invention presents a new concept in tunneling. This invention utilizes in one typical embodiment a device for inserting into the earth a pair of diametrically opposed staves which, for example, could be tubular elements through which soil treatment material may be introduced. On one side of each stave is a tongue and the other side is provided with a grooved extension. The device of this invention can be mounted on the front of a tractor or other suitable device such as a car that can move on a rail bed. The staves are attached to a large support structure which in turn is connected to the tractor or other implement. In one embodiment, the tractor is moved forward during sonic activation, forcing the staves into the ground. While the tractor is moving forward, the staves are individually resonantly sonically vibrated. This substantially loosens the dirt surrounding them, easing the penetration into the ground. The structure that supports the two staves is successively rotated about its center axis, placing additional staves by side about the circumference of the structure. Due to the tongue and groove construction, a tightly sealed circular tube is formed from the plurality of staves. The center earth core is then removed, and additional series of such staves is continued for the length of the tunnel. In a second embodiment of the invention, the tractor or implement containing the power equipment remains stationary while the support structure for the staves is moved forward along a center guide rod that additionally engages the earth. This center guide rod serves to additionally assure accurate centering of the support structure, resulting in precise positioning of the stave elements.
It is believed that the invention will be better understood from the following detailed description and drawings in which:
FIG. 1 is a pictorial representation of the device of this invention mounted on a suitable tractor;
FIG. 2 is a sectional view taken along lines 2--2 of FIG. 1;
FIG. 3 is a front view taken along lines 3--3 of FIG. 1;
FIG. 4 is a sectional view taken along lines 4--4 of FIG. 2;
FIG. 5 is a sectional view taken along lines 5--5 of FIG. 2;
FIG. 6 is a top plan view taken along line 6--6 of FIG. 5;
FIG. 7 is an enlarged cross-sectional view of the staves taken along lines 4--4 of FIG. 3;
FIG. 8 is a pictorial representation of a second embodiment of this invention;
FIG. 9 is a pictorial representation of the second embodiment of this invention, disclosing the removal of staves from a storage car;
FIG. 10 is a partially sectioned view taken along lines 7--7 of FIG. 5;
FIG. 11a is a pictorial view of the second embodiment of this invention wherein the staves are in a starting position;
FIG. 11b is a pictorial representation of the second embodiment of this invention wherein the staves are in a final inserted position; and
FIG. 12 is an enlarged cross-sectional view of a plurality of flat interlocked slightly curved staves.
It has been found most helpful in analyzing the operation of the device of this invention to analogize the acoustically vibrating circuit involved to an equivalent electrical circuit. This sort of approach to analysis is well known to those skilled in the art and is described, for example, in Chapter 2 of "Sonics" by Hueter and Bolt, published in 1955 by John Wiley and Sons. In making such an analogy, force F is equated with electrical voltage E, velocity of vibration u is equated with electrical current i, mechanical compliance C m is equated with electrical capacitance C e , mass M is equated with electrical inductance L, mechanical resistance (friction) R m is equated with electrical resistance R, and mechanical impedance Z m is equated with electrical impedance Z e .
Thus, it can be shown that if a member is elastically vibrated by means of an acoustical sinusoidal force F o sinωt (ω being equal to 2 π times the frequency of vibration), that
Where ωM is equal to 1/ω C m , a resonant condition exists, and the effective mechanical impedance Z m is equal to the mechanical resistance R m , the reactive impedance components ωM and 1/ω C m cancelling each other out. Under such a resonant condition, velocity of vibration u is at a maximum, power factor is unity, and energy is most efficiently delivered to a load to which the resonant system may be coupled.
It is important to note the significance of the attainment of high acoustical "Q" in the resonant system being driven, to increase the efficiency of the vibration thereof and to provide a maximum amount of energy for the grinding operation. As for an equivalent electrical circuit, the "Q" of an acoustical vibration circuit is defined as the sharpness of, resonance thereof, and is indicative of the ratio of the energy stored in each vibration cycle to the energy used in each such cycle. "Q" is mathematically equated to the ratio between ωM and R m . Thus the effective "Q" of the vibrating circuit can be maximized to make for highly efficient high-amplitude vibration by minimizing the effect of resistance in such circuit.
Of significance in the implementation of the method and devices of this invention is the high acceleration of the components of the elastic resonant system that can be achieved at sonic frequencies. The acceleration of a vibrating mass is a function of the square of the frequency of the drive signal times the amplitude of vibration. This can be shown as follows:
The instantaneous displacement y of a sinusoidally vibrating mass can be represented by the following equation:
y = Ycosωt 2.
where Y is the maximum displacement in the vibration cycle and is equal to 2πf, f being the frequency of vibration.
The acceleration a of the mass can be obtained by differentiating equation (2) twice, as follows:
a = (d 2 y/dt 2 ) = -Yω 2 cos(ωt) 3.
The acceleration a thus is a function of Y times (2πf) 2 . At resonance, Y is at a maximum and thus even at moderately high sonic frequencies, very high accelerations are achieved making for correspondingly high vibrational forces at the grinding interfaces.
In considering the significance of the parameters described in connection with equation (1), it should be kept in mind that the total effective resistance, mass, and compliance in the acoustical vibration circuit are represented in the equation and that these parameters may be distributed throughout the system rather than being lumped in any one component or portion thereof.
It is also to be noted that an orbiting-mass oscillator may be utilized in the device of the invention that automatically adjusts its output frequency to maintain resonance with changes in the characteristics of the load. Thus, in the face of changes in the effective mass and compliance presented by the load, the system automatically is maintained in optimum resonant operation by virtue of the "lock-in" characteristics of applicant's unique orbiting-mass oscillator. The orbiting-mass oscillator automatically changes not only its frequency but its phase angle and therefore its power factor with changes in the resistive impedance load to assure optimum efficiency of operation at all times.
Turning now to the drawings, FIGS. 1 and 2 particularly, there is seen a tractor bogie device 11 having a support structure 13 to carry the device 15 of this invention. Mounted on the tractor bogie 11 is a large power unit 16. A motor in housing 17 is attached to the front of the power unit 16. Rigidly affixed to the housing 17 and extending forward therefrom is an inner support cylinder 19. Two horizontal channel beams 20, one above and one below the inner cylinder 19, serve to support it relative to the support structure 13. Mounted in a turning engagement with inner cylinder 19 is an outer cylinder 21, which is provided with a gear ring 23 about its end adjacent the tractor. The gear 23 engages a small pinion gear 24 which is connected to a motor 25 so as to controllably rotate the cylinder 21 about the inner cylinder 19. The outer cylinder 21 has rigidly affixed thereto a third cylinder 22. A large frame structure 26 and 27 extends radially from the third cylinder 22. The cylinder 22 serves to absorb the load from the frame structure 26 and 27 rather than have it placed on the rotatable cylinder 21. The frame structure 26 has in combination two radially extending sets of beams 27. Each set 27 of beams is connected to two arms 28 separated from each other by cross-plates 29. Additionally, the outer cylinder 22 has welded thereto two circumferential U-shaped rings 30. Attached to the rings 30 are cross-members 31 which rigidly support arms 28.
The frame structure 26 additionally serves to hold two orbiting-mass oscillators 32 180° apart at the outer extremity. The orbiting-mass oscillators 32 can be of a type shown, for example, in FIG. 21 of U.S. Pat. No. 2,960,314. The oscillators 32 are driven from motor 17 which rotates shaft 33 located concentrically within inner cylinder 19 and is supported therefrom through support structures 35 and bearings 37. Shaft 33 rotates gear 39 located on the end thereof. In turn gear 39 engages beveled step-up gears 41, which impart rotation to flexible shafts 43. Shafts 43 in turn are supported by bearings 45 mounted on plates 29, and drive oscillators 32.
The oscillator 32 is affixed to a hydraulic clamp 47 which in turn holds the stave 49 to be driven into the earth. Disposed behind the oscillator 32 and affixed to the frame structure 26 through a mounting bracket 51 is a pneumatic or hydraulic spring device 53. The oscillator 32 vibrates essentially in the direction of the arrow 55 which corresponds to the axis of the stave 49. Thus, the oscillator must be free to move between the bracket 51 and an outer bracket 57, which is further secured to the spring device 53.
Considering now FIG. 4 together with FIG. 2, it can be seen that plate 51 is provided with a slotted aperture 59 to allow for the vibratory movement of oscillator 32 and attached flexible shaft 43. A rod 61 is affixed at one end to the oscillator 32 and at the other end to a movable piston 63, disposed within the housing of the spring device 53. An inlet line 65 can conduct an elastic pressure fluid such as either air or oil to a cavity 67 behind the piston 63 so as to maintain bias force to cushion the vibratory effect of the oscillator.
Turning now to FIGS. 5 and 6 there is seen an hydraulic clamp arrangement 47 utilized to hold the stave elements 49. A pair of jaws 71 are pivotally connected to a base member 73. The base member 73 is in turn connected to a piston element 75 which moves in an area 77 of a housing 79. The walls of the housing are tapered at 81 along the outer surface of the jaws 71 so as to force them into tight contact with the stave element 49 in a close position as shown in FIG. 5. An outer housing 83 surrounds the inner housing 79. In order to appreciate how the jaws work, it must be understood that the stave element 49 is relatively stationary due to its weight and also due to its fixation to the stave elements that are previously in the ground. Thus, when hydraulic fluid is brought into line 85 and exits from line 87, the inner housing 79 will move relative to the outer housing 83 to the dotted position shown, allowing the jaws to disengage themselves from the stave 49. Virtually any type of hydraulic jaw is suitable for the herein application and does not form a part of this invention. The jaw shown in FIGS. 5 and 6 is merely illustrative of one type that could be utilized for holding the staves so that they can receive the vibratory energy from the oscillators utilized.
FIG. 7 is an enlarged view of a plurality of cylindrical staves 49 showing the interlocking arrangement. As seen, each stave is provided with a grooved extension 91 on one side and a tongue portion 93 oppositely disposed so that they can fit into an interlocking arrangement as shown.
The resonant vibratory energy imparted to the staves by the resonant frequency oscillators 32 during driving into the earth serves to penetrate the earth, and also to reduce the frictional resistance between the adjacent members so that a relatively tight-fitting tongue and groove connection can be achieved as shown in the figure.
In the operation of the device as shown in FIGS. 1-6, a first complete circle of staves is resonantly driven into the earth to their entire length. New staves are then welded onto the exposed end of the staves driven into the ground, and the new staves are subsequently driven to their entire length, thus forcing the original staves further into the earth. This procedure continues forming one circle after another of staves welded onto each other to the desired final depth of the tunnel. In this arrangement, the device 15 for driving the staves never travels more than the length of the staves and does not generally enter the cavity formed, but remains outside driving the series of staves as indicated.
FIGS. 8-11b disclose a device for driving staves into the earth for tunneling in the manner previously described. However, the operation of the device differs from the one shown in the previous figures in that it continually advances through the tunnel, driving a series of successive staves not axially affixed to each other. The device in FIGS. 8-11b is shown schematically since it utilizes essentially the same features of the device shown in the other drawings.
Turning now to FIGS. 8-10, the device of the second embodiment is shown schematically to depict the novel approach for placement of the staves in a successive telescoping fashion into the ground. The staves in this embodiment will have the flat slightly curved configuration as shown in FIG. 12. The staves 101 as seen in FIG. 8 are successively placed in the ground 103 in the aforementioned telescoping fashion, such that each series of staves slightly overlaps the other. The circumference of the tunnel 105 will pass through the center point 107 of each series of staves. Thus, the tunnel will have nearly a constant diameter. To accomplish this, the staves must be placed at a slight angle as shown in FIG. 8.
After a series of staves is placed into the ground in a complete circumference, the ground is removed and a second series is then inserted. This process is continually repeated until the tunnel is achieved. To accomplish this, the apparatus 109 of this embodiment comprises a tractor vehicle 111 that can move on a bed 113 laid in the formed tunnel or on rails, as desired. A guide rod 115 passes through the vehicle 111 and engages the earth at its front pointed end 117. The guide rod 115 has four racks 118 equidistantly disposed on its outer perimeter. As particularly seen in FIG. 8, the vertically disposed racke engage motor driven gears 120 located within the tractor device 111, and serve to move the tractor device relative to the guide rod 115. Before the staves are placed, the guide rod 115 is accurately centered in the tunnel and firmly engages the earth.
Mounted on the guide rod 115 in front of the tractor device 111 are two essentially identical stave support units 121 and 123, respectively, which separately move on the horizontally disposed racks by pairs of drive motors 125 and 127 located therein. As particularly seen in FIG. 10, the front unit 121 actually has a pair of opposite drive motors 125 for engaging the horizontal racks. The motors 127 in the rear unit 123 are also similarly disposed.
Each movable stave support unit 121 and 123, respectively, has a pair of oppositely disposed extendable arms 129. The arms can be pneumatically or hydraulically operated through lines 131 and 133 respectively, which in turn are connected to reel devices 135 that automatically retract the lines when the devices 121 and 123 are adjacent the tractor. In the forward device 121, the extendable arms 129 thereon pivotally engage two pneumatically operated clamping jaws 137 which can be of a construction similar to that shown in FIG. 5. The arms 129 of the rear unit 123 pivotally engage units 139 which are similar to the embodiment shown in FIG. 2, for example, in that they combine a pneumatic jaw, an oscillator and pneumatic spring in essentially the same arrangement that is shown in FIG. 2.
For simplicity, not all of the lines to direct the hydraulic fluid, or air in case of pneumatic operation, are shown in the figures. It should be understood that additional reels and lines are obviously required in order to operate all of the arms as well as the oscillator and pneumatic jaws. To operate the device of this embodiment, the tractor element 111 is moved to adjacent the rear of the center guide rod 115 as seen in FIG. 9. The jaws 137 of the movable front unit 121 pick up two stave elements 101 from a storage can 138, as seen, carrying them toward the front of the guide rod 115 to engage the earth, as seen in FIG. 11a. The arms 129 of the front movable unit 121 are extended as shown in FIG. 11a such that the elements 101 are brought in contact with the previously inserted staves. The arms 129 of the rear movable unit 123 extend such that the jaws contained in the outer units 139 enclose the rear end of the stave elements 101. The tractor 111 remains static on the bed 113, while the drive motors 127 in the rear unit 123 move the staves forward into the earth during the operation of the oscillators contained in the end units 139 to a final position shown in FIG. 11b.
After two oppositely disposed stave elements 101 are inserted, as seen in FIG. 11b, the entire center rod 115 together with the devices 121 and 123 is rotated to provide adjacent staves. This rotation can be accomplished as seen in FIG. 8 by the use of a motor 141 driving a gear 143 located on the tractor device 111. A large ring gear 145 encloses the motors 120 and is affixed thereto. When the motor 141 is actuated, ring gear 145 rotates the motors 120 which are locked to the back portion of the center member 115. This in turn causes the rotation of the entire element within the tractor 111.
Turning to FIG. 12, there is seen a cross-section of typical stave elements 101. As can be seen, the elements are flat and slightly curved, having a grooved portion 147 on one side and a tongue 149 on the other, so as to effect the arrangement shown of interlocked staves.