Abstract: An improved book block transport channel has adjustable lateral guide members, which define the channel width, and an adjustable skid plate with support finger projections outwardly in two opposed directions. The skid plate support fingers are received in slots in the guide members and define a discontinuous channel floor adjacent the guide members. The openings in the channel floor and the slots are partly bridged by guide rails which are mechanically coupled to a respective guide member and to the support fingers which are received in the slots in that guide member.

Abstract: In a system for setting the vertical position of the rounding bar in a book block rounding and backing machine which possesses a support bearing unit, within which the rounding bar that acts on the spine of the book block reciprocates, the support-bearing unit is adjusted in the vertical direction, in side frames, by means of adjusting spindles, so as to set its vertical position, and is immobilized in the side frames by means of a clamping arrangement. The support bearing unit 7 is carried in a frame 4 and can, with the rounding bar 3, be deposited, by their own dead weight, onto the spine of a book block 1. The support bearing unit 7 is supported on intermediate supporting elements 24, 24a so that it cannot descent below them, while being free to slide upwards. The intermediate supporting elements 24, 24a are lowered by means of adjusting spindles 22 which can be motor driven.