light in weight and carrying a plurality of pneumatic cylinders not illustrated fed with air from respective nipples 92 and having piston driven output rods 94 the body member 91 has cylindrical chambers formed therein and receives the pistons 95 with the rods extending out the end remote from the body member 93 the latter having the input nipples 92 a spring 97 biases the rods inwardly the cylinders and thus the output rods 94 are arranged in two vertical spaced apart rows with the cylinders in one row staggered relative to those in the other row so that coupling members 96 may be attached to each rod and provide clearance for extending freely in a preferred forms of the module there are twenty cylinders in an 1 8 gauge machine and twenty four cylinders in a 1 10 gauge machine and half of the cylinders are in each row disposed at each lateral end integral with the lower surface of the module is a respective tube 99 only one of which is shown within which a screw 101 extends for securing the module to the mounting bar 49 each of the coupling members 96 includes a slot 98 with an internal nub 100 the.