bushes are also conceivable in contrast through openings of the second type 61 63 65 67 69 71 also illustrated as bores in fig9 and fig1 are provided symmetrically uniformly spaced over the entire circumference and with equal circular arc segments between the openings the receiving groove for the band 9 is an internal groove 33 located beneath the encircling connection groove 75 of the connection p the pressure connection in fig6 the detail z of the central guide is shown enlarged in fig7 the stepped edge of the internal groove 33 according to fig6 is shown again enlarged it can be seen that the internal groove 33 is a stepped internal groove having two widths 39 41 the internal groove 33 consists of a deeper internal groove 35 and a shallower internal groove 37 located in the region of the shallower internal groove 37 is the ring 7 which closes the through openings such as for example 17 in one pressure direction and opens them in the other pressure direction if fig7 and fig8 are considered more closely the true to detail design of the internal groove 33 can be seen the stepped edge of the internal groove 33 prevents the ring 7 from.