HOLLOW-CORE FORMING MANDREL FOR MAKING HOLES IN FERROCONCRETE SLEEPERS TO FIT THE INSERTION BOLTS Russian patent published in 1995 - IPC

FIELD: building engineering. SUBSTANCE: hollow-core forming mandrel for making holes to fit the insertion bolts in ferroconcrete sleepers has a housing with curvilinear cross-section. It rests on the insertion washer with a rectangular window and has a tail with rectangular cross-section. Main and additional vertical angular notches are formed on the lateral surface of the housing. The surfaces of the main notches are shifted by 80-110 one relative another. The tail is placed in the remote member located between the insertion washer and the underrail landing of the pallet. The housing with curvilinear cross-section is fixed on the underrail landing of the pallet by means of a core-type tie member and an interchangeable wedge prop placed in the central longitudinal channel. The wedge prop has a working surface sloped to the longitudinal axis at an angle exceeding the angle of self-braking and contacting with the core-type tie member. The lengths of the greatest axis of the curvilinear cross-section of the housing and the diagonal lines of the cross-section of the remote member exceed the lengths of diagonal lines of the tail cross-section and of the window of the insertion washer 1.01-1.25 and 1.02-1.28 times correspondingly. The height of the remote member is equal to 0.85-0.98 of the tail length and it can be made of the thermoplastic material with the melting point not exceeding 75-85 C. EFFECT: enhanced efficiency. 4 cl, 8 dwg