Automatically driven pile driver drilling device

#In order to produce drill holes in the ground or for the purpose of destroying and replacing pipelines placed in the ground, pile driver drilling devices are used, which have a percussion piston arranged inside the device that can be moved back and forth.

#Pile driver drilling devices of this type have been exceptionally suitable for the trenchless placement of lines in the ground and for the replacement of pipelines in the ground by destroying and then replacing them. They require a change in direction in order to be able to produce, for example, blind holes, or in order to avoid the need for digging up a device restrained by an insurmountable obstacle in the ground, instead, being able to move out of the bore hole it already created by means of-reverse operation.

#For a change in direction, numerous systems are known, all of which are based on the fact that the impact energy of the percussion piston, moving axially inside the housing of the device, is introduced into the housing of the device, not in the direction of advance, but in the opposite direction, with the aid of a rearward housing stop for the percussion piston. This takes place in a simple manner, whereby adjusting a control slide inside the housing of the device, whose control edges are displaced axially, determines the point at which the ventilation of the working space, located before the percussion piston in the area of the tip of the device, takes place. At that time the respective control edges are placed opposite the direction of advance, so that the working space is ventilated at a later point in time and, accordingly, the percussion piston with its rearward front surface impacts with a stop forming a rigid part of the housing.

#In the following text, the invention is explained in greater detail with the aid of the examples shown in the drawing, wherein

#FIG. 1 shows a change in direction, in which the positive directions of the control air and of the pressure spring assume the same direction and the control box is in its advance position;

#FIG. 2 shows an enlarged representation of the rearward portion of the pile driver drilling device, similar to FIG. 1, with the front portion of the guide pipe and the control box in their advance position;

#The pile driver drilling device consists of a cylindrical housing (1) with an impact point (2) and a percussion piston (4), provided with radial control openings (3), in whose rearward part is located a rear working space (5). In the rearward part of the housing (1), a stop ring (6), with ventilation openings (7) parallel to the axis, is built in.

#Through the stop ring (6) extends a guide pipe (8) which, on the one end, is connected with a working air or compressed air hose (not shown), and on the other end, extends with its front end into the working space (5) of the percussion piston (4). The guide pipe (8) consists of an inner pipe (9) and a shorter outer pipe (10), between which an annular space (11) is located, with a bore (12), such as a front bore, opening into the working space (5). The inner pipe (9) has one or several radial control openings (13), and the outer pipe has radial control openings (14). Into the annular chamber (11), an axially adjustable control box (15) extends, which is guided between a pressure spring (16), and a stop at the inner pipe (9).

#The control box (15) has radial control openings (17), as well as a front pressure chamber (18), connected with the inner pipe (9), carrying compressed air via the control opening (13), and a pressure chamber (19), which is connected via a control air line in the form of a control air channel (20) in the inner pipe wall, and a valve (not shown), is connected with a control air source. Furthermore, the control box has a stop edge (21), and an interior stop collar (22), while the inner pipe (9) is provided with a stop collar (23). Furthermore, the outer pipe is provided with an outer recess (24).