MOLD TURNING CAM, SQUARE BLOCK, AND PINION
Reading edition
The mold turning cam, known as cam No. 3, has attached to its side the long and short gear segments which impart rotation to the mold turning pinion and square block as the cam revolves. The square block and pinion are found on the inside of the mold gear arm. The gear segments on the mold turning cam turns the pinion, the pinion turns the mold turning shaft, and the mold turning shaft turns the mold disk, through the mold disk pinion which meshes with the mold disk. The short segment turns the mold disk one-quarter of a revolution so as to bring the mold disk into casting position. The long segment turns the disk three-quarters of a revolution, bringing the mold and disk in ejecting position. The mold disk makes one complete revolution in one revolution of the cams.
When the disk makes one-quarter revolution, it is advanced so as to lock the stud block on the vise with the studs on the mold disk, and the slug is cast; the mold then is withdrawn and makes a three-quarter revolution, advancing again and locking to eject the slug. When the mold disk makes the quarter and three-quarter revolutions, all lost motion must be taken up by the square block on the pinion. If there is any lost motion, the studs on the mold disk would not be parallel with the stud blocks on the vise so that they could not enter them without coming in contact with the rim of the stud block.
Adjusting Shoes
On the mold turning cam are two adjustable steel shoes for the purpose of taking up the play between the shoes and the square block when in the casting and ejecting position. These shoes are adjusted by screwing in on the bushing screws that extend through the cam and bank against the shoes. Each shoe is held in place by two machine screws that extend through the bushing screw into the shoe. When adjusting the shoes care must be taken to make them parallel. The distance from the front end of each shoe to the outside of the cam must be the same as it is from the back end of the shoe to the outside of the cam. If these shoes are adjusted wider at the back than at the front they act as wedges as they go down by the square pinion, and may break the cam at the weakest point. If a shoe is set too tight against the square pinion it will break the cam. All that is necessary is to adjust them so as to take up the lost motion between the shoes and the square pinion. It is better to use a micrometer to measure the shoes to make sure they are parallel. Allow a trifle lost motion between the square block and the shoes, because it is better for them to have a little play than to be too tight and perhaps break the cam.
The square block and pinion are held in position on the shaft by a set screw, and there is no adjustment except to have this screw on the top when the machine is in normal position. The screw passes through the square block to the shaft and must enter the spot drilled on the shaft for the point of the screw so as to hold the pinion tight. On the two sides of the square block are two steel shoes, which are held to it by screws. These shoes can be renewed when they become worn.