HOLE-FORMING CORE Russian patent published in 1994 - IPC

FIELD: producing ferrum concrete articles. SUBSTANCE: hole-forming core has a case wherein an exciter of force vertical pulses is received. The exciter is made of strikes which are in contact with flexible members mounted within the case. Working chambers of the strikers are coupled with a fluid source through a branch pipe and formed with lateral and longitudinal baffles secured in the space of the case. One of the longitudinal baffles has openings for connecting of the working chambers with each other and mounting the strikers. EFFECT: improved design. 7 cl, 8 dwg