초록 ▼

A ram boring implement has a pneumatically driven percussion piston (16), which is movable in the axial direction in a reciprocating manner in a housing (12), and a control sleeve (24) which is axially adjustable for reversing the direction of motion of the ram boring implement and is acted upon by

A ram boring implement has a pneumatically driven percussion piston (16), which is movable in the axial direction in a reciprocating manner in a housing (12), and a control sleeve (24) which is axially adjustable for reversing the direction of motion of the ram boring implement and is acted upon by the pressure in one (20) of the pressure chambers (18, 20) formed on both sides of the percussion piston (16). The control sleeve (24) can be adjusted by means of a spindle drive (30, 50) by turning a compressed air supply hose (26). According to the invention, the control sleeve is arranged on a core (30, 34), supported in an axially fixed manner on the housing (12), so that the control sleeve itself forms only a relatively small annular effective area (52) acted upon by pressure. This makes it possible for the control sleeve to be moved forward or toward the rear without the compressed air feed having to be interrupted.

대표청구항 ▼

A ram boring implement, comprising: a generally cylindrical housing; a pneumatically driven percussion piston axially movable in a reciprocating manner in the housing and defining a first pressure chamber in front of it and a second pressure chamber behind it; a core member mounted axially within sa

A ram boring implement, comprising: a generally cylindrical housing; a pneumatically driven percussion piston axially movable in a reciprocating manner in the housing and defining a first pressure chamber in front of it and a second pressure chamber behind it; a core member mounted axially within said housing; said core member having an end portion coaxially projecting into the interior of said housing; a compressed air supply, comprising a compressed air supply hose connected to the housing; and a control sleeve which is axially adjustable for reversing the direction of motion of the ram boring implement, said control sleeve being arranged on an outer circumferential surface of said end portion and including an annular effective area that is acted upon by the pressure in the second pressure chamber; said core member including a spindle drive rotatably mounted in said housing for adjusting the axial position of the control sleeve in response to turning of the compressed air supply hose; said spindle drive having a first end connected to said compressed air hose for rotation therewith and a second end threadedly connected to said control sleeve to adjust the axial position of the control sleeve relative to the spindle drive while the ram boring implement is in operation.