blocks 160 and 162 the cage plate hold up brackets 140 and 142 are somewhat l shaped and one arm thereof is affixed to the bottom plate of the inventive back up tongs and the other ends of the hold up brackets 140 and 142 are provided with a support bracket 166 which has bolted thereto cam followers or the like two of which may be seen at 168 and 170 it is these cam followers 168 and 170 which bear against the bottom surface of the bottom cage plate 96 and support its weight in cooperation with the hydraulic cylinder 158 although two hold up brackets 140 and 142 are shown in fig6 it is apparent that any number of hold up brackets may be used although a single bracket may not be desirable for adequately supporting the cage plate assembly 36 the operation of this inventive hold up system will be explained in detail hereinafter the operation of the inventive back up tongs will be described based on the preceding figures as well as additional fig8 10 when it is desired to make up or break out a pipe joint or casing joint employing the inventive back up tongs in combination with a power tong unit the units are typically suspended from the top of the drill rig by a chain or line so that the units may then be swung into place the back up tongs must then be clamped onto the lower of the two pipes after the pipe has been placed into the.