The SPG Series encompasses a unique design. The jaws and the pistons are an integral assembly. These grippers have just three moving parts, therefore the design is both compact and lightweight.
Jaw construction
A pair of ground, stainless steel guide shafts (which double as air pistons) are press fit and pinned to each gripper jaw. Shafts are placed diagonally and spaced far apart for maximum jaw stability.
Only 3 moving parts
The two jaw units are linked by the third moving part, a rocker arm, that synchronizes jaw motion. The arm does not drive the jaws so wear is minimal. The shaft/pistons of each jaw pass freely through enlarged holes in its mate. "C" in the photos indicates the opposing piston faces to which air pressure is applied for jaw closing. "O" targets the opposing “jaw open” faces.
Cylinder blocks are symmetrical
Four cylinders are bored in each of two blocks and connected by internal air passages to the "C" and "O" piston faces. Each cylinder incorporates permanently lubricated, high-performance linear bearings that provide clean, drip-proof operation and allow use of a non-lubricated air supply. Opening and closing forces are equal, allowing the grippers to be used for both OD & ID gripping.
Porting block completes the housing
No troublesome gibs to wear or adjust. Four dowel pins align the porting block perfectly with the cylinder blocks. Eight high-performance linear bearings guide the four pistons through the entire length of the gripper body. Centering accuracy is maintained to .002" and side play is .0015" or less per jaw. Metal name plates provide coverage and protection on both sides.
