Ram boring device

Abstract

A ram boring device has a pressurized-fluid driven striking piston in a device housing and a rotating reversing device configured to urge the striking piston from a forward operation to a reverse operation, in order to create oblique or horizontal bores in the ground. A piston chamber of a rotary piston drive is connected to a control fluid line.

Claims

1. A ram boring device, having: a pressurized-fluid driven striking piston in a device housing and in selective communication with a service fluid pressure and a reversing device of the striking piston for controlling the operation of the boring device between a forward operation to a reverse operation in order to create oblique or horizontal bores in the ground, wherein a piston chamber of a rotary piston drive is connected to a control fluid pressure via a control fluid line for selectively rotating the rotary piston drive and unlocking the reversing device via an autonomously and independently controlled application of the control fluid pressure to a rotary piston of the rotary piston drive.

2. The ram-boring device according to claim 1, wherein the application of control fluid pressure to the rotary piston via the control fluid line can be controlled autonomously and independently of the application of the service fluid pressure.

3. The ram boring device according to claim 1, wherein the control fluid line discharges into the piston chamber of the rotary piston drive.

4. The ram-boring device according to claim 3, wherein a portion of the control fluid line is arranged inside of a service fluid line.

5. The ram boring device according to claim 1, further comprising a valve for selectively controlling the flow of fluid through the control fluid line.

6. The ram boring device according to claim 1, wherein the rotary piston drive is disposed inside of the device housing.

7. The ram boring device according to claim 1, wherein the rotatory piston drive comprises a fluid-powered rotatory piston actuator.

8. The ram boring device according to claim 1, further comprising a control pipe comprising a first slot and a second slot, wherein a locking crosspiece of the reversing device is selectively lockable with respect to the control pipe in a first position associated with the first slot and a second position associated with the second slot.

9. The ram boring device according to claim 1, wherein the reversing device comprises a control sleeve spring biased to move from a position for reverse operation of the striking position to a position for forward operation of the striking piston responsive to a decrease in the service fluid pressure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described in greater detail below on the basis of an exemplary embodiment, which is depicted in the drawings.

(2) FIG. 1 shows a longitudinal section of the rear end of a ram boring device in its forward operation position;

(3) FIG. 2 shows the longitudinal section from FIG. 1, however in the reverse operation position;

(4) FIG. 3 shows a perspective view of the control pipe of the ram-boring device according to FIGS. 1, 2 in the forward operation position;

(5) FIG. 4 shows the control pipe according to FIG. 3, in its reverse operation position, however,

(6) FIG. 5 shows a cross-sectional view along the line V-V of FIG. 1;

(7) FIG. 6 shows a cross-sectional view along the line VI-VI of FIG. 1 and

(8) FIG. 7 shows a cross-sectional view along the line VII-VII of FIG. 1.

DETAILED DESCRIPTION

(9) The ram-boring device 1 has a cylindrical housing 2, of which, however, only the rear part with its screw tail end 3 is depicted. A striking piston 4 that can be moved back and forth is mounted in the housing 2, the reverse movement of which striking piston is delimited by an annular impact surface 5. The striking piston 4 is oscillated by a pressurized fluid supplied via a line 6 and thereby provides the kinetic energy of said piston to a head of the ram boring device located in the front part of the housing 2, or to the device housing via the annular impact surface 5, the head of the ram boring device of which is disposed such that it can be moved axially within the housing 2.

(10) The pressure fluid line 6 is connected to a pivoted control pipe 9 via a two-piece coupling piece 7, 8, which control pipe is pivoted with respect to a locking sleeve 19. This control pipe is mounted on one side at the front end in a control sleeve 10 in the cylinder chamber 11 of the striking piston 4, and on the other side at the rear end in a ventilation block 12, which is disposed in the tail end 3 of the housing 2. The control sleeve 10 is connected to the control pipe 9 via an elastic bushing 13. This sleeve is mounted in an annular groove 14 of the control pipe 9, which is connected to an annular shoulder 15 of the control pipe 9.

(11) The shoulder 15 has a recess, which is not apparent, and which is open towards the tail end of the device (FIGS. 1 and 2), in which recess the front end of a cylindrical helical spring 16 engages. The helical spring encloses the control pipe 9 and is fixed at the rear end 17 thereof in the recess 18 of a pivotable locking sleeve 19 located opposite the control pipe 9. These parts are a part of the rotating reversing device according to the invention, as is evident from the sectional drawings in FIGS. 5 through 7.

(12) This reversing device essentially comprises a rotary piston drive in the shape of a finned tube component 20 having longitudinal fins 21, 22. The finned tube component 20 forms in conjunction with the locking sleeve 19 a rotary piston 23 connected to the locking sleeve 19 as well as the piston chamber 24 of the rotary piston drive with the cylindrical outer sleeve 32, to which separate instrument air is applied via an instrument air line 25 having a instrument air valve 26.

(13) As an alternative locking method, the control pipe 9 has a crosswise slot 27, 28 in the rear part thereof, which slots are spaced apart from one another, and into which a locking crosspiece 29 alternatively engages. The crosswise slot 27 determines the forward operation position (FIG. 1) and the crosswise slot 28 determines the reverse operation position (FIG. 2) of the control pipe 9. The two crosswise slots 27, 28 thereby define the two operating positions of the control pipe 9.

(14) The sectional view in FIG. 6 depicts two fixed stop bars 30, 31 located opposite one another, which delimit the movement of the rotary piston during the reversal using the instrument air valve 26.

(15) The reversal is achieved in such a way that the piston chamber 24 of the rotary piston 23 is pressurized by opening the instrument air valve 26. After the rotary piston has then reached its end position, the helical spring 16 slides the control sleeve 10 with the control pipe 9 forward as a result of a decrease of the pressure in the pressurized air line 6. To this end, the pressure is reduced to such a degree that the helical spring 16 moves the control sleeve 10 out of the position for the reverse operation depicted in FIG. 2, into the position for the forward operation (FIG. 1) in opposition to the residual pressure of the pressurized medium (service air) still exerted in the cylinder chamber 11 of the striking piston 4. The rotary piston 23 can be vented during the movement of the control pipe 9 from the position for the reverse operation depicted in FIG. 2, to the position for the forward operation (FIG. 1). In other words: Instrument air is only applied to the rotary piston to unlock the control pipe 9, i.e. for a very brief period of time.

(16) This is possible because the helical spring 16 places the control pipe 9 in the front position thereof for the forward operation (FIG. 1) after the rotary piston 23 has been vented, in which position a locking crosspiece 29 engages in a rear crosswise slot 28 of the control pipe 9 (FIG. 1) and thereby prevents an axial movement of the control pipe. As soon as this is the case, the pressure of the service air can again be increased and the forward operation can begin.

(17) In order to initiate the reverse operation, the device must first be unlocked with the help of the rotary piston 23 pressurized with instrument air, while maintaining the full pressure level of the service air, in such a way that the control pipe 9 can move, under the influence of the service air, from its position in FIG. 1 into the position according to FIG. 2. In this position, the front crosswise slot 27 and the locking crosspiece 29 once again engage (FIG. 2) under the influence of the helical spring 16 when the rotary piston 23 is no longer pressurized, and the reverse operation begins at full pressure level.