other linking mechanism 56 so as to create the loop of bristle blocks 20 the loop 20 rotates around the rotatable end units 30 and 32 such that the contact surface 54 of each block 50 faces upwardly through about half of each rotation of the loop of bristle blocks 20 the loop 20 rotates in a clockwise fashion at the end unit 32 the bristle blocks change direction and are turned or rotated through 180 u00b0 such that the contact surface 54 faces downwardly a movable head bristle bed cleaner 70 is positioned at a location l where the bristle blocks have been rotated through about 150 u00b0 the cleaner 70 is positioned at a level below the level of the rotatable end units 30 and 32 the moveable head bristle bed cleaner 70 is mounted on one or more brackets 75 the brackets 75 are mounted to an end plate 76 which is fixed to the main members of the frame 12 as best seen by reference to fig3 the cleaner 70 includes a linear actuator which is designed to move a cleaning head discussed below of the cleaner 70 across the width w l of the loop of bristle blocks 20 in the embodiment shown in fig3 the linear actuator is a rodless cable cylinder 80 although linear actuators such as those available from bimba manufacturing can be used instead of a.