We have a No. 4 (S/N 8655) and have a problem with the foot pedal mechanism that interacts with the gripper trip assembly. The foot pedal is connected to the pivot mechanism on the non-operator side of the press by way of the bicycle chain on the outside of the press cabinet. I had the cylinder rolled to the end of the bed and was oiling the gripper trip assembly and pivot mechanism attached to the foot pedal. I happened to hit the foot pedal and heard a ‘snap’. At that point the foot pedal dropped to the floor and did not come back up to the normal position. The gripper trip assembly had moved outward to the point that the spring (MRS-106) was fully extended and away from the side of the press. I found a small spacer on the floor. It has a 1/2″ outside diameter with a 1/4″ center hole and is 1/4″ thick. The manual we have does not have any diagram of the pivot mechanism which is attached to the foot pedal via the chain and has a tongue that is between the gripper trip assembly and pushes on the gripper trip assembly to open the grippers when the cylinder is at the feed table. Does a diagram of this part exist which would assist me in determining what happened, how to fix it, and if the spacer is key to the repair?
The problem happened late in the evening so I have yet to take steps to remove any parts. It is also difficult to provide photos because limited space in out print shop means we have the non-operator side of the press fairly close to the wall. I thought I would check with the experts for help before I begin taking things apart.
Can I access the photos mentioned in the above posts?
These photos, courtesy of Jenny Wilkson, show the 4 OS at the School of Visual Concepts in Seattle.
Thank you for the photos, Paul. They point out a couple of things. First, the foot pedal mechanism on our press is definitely a home-grown one. Secondly it shows and confirms what Fritz has told us about an independent circuit breaker attached to our press. Namely, it also is a add-on item. I will get with NA Graphics about the possibility of a proper foot pedal mechanism.
Here are photos of the pedal assembly on a well-preserved old style No. 4.
I removed the trip assembly and the foot pedal mechanism and found the cam on the trip assembly was broken (photos attached). I suspect this is the source of the problem since I could find no broken area on the foot pedal mechanism. This mechanism has had a lot of repair done to it, and may even be a home-grown part. I would like to eventually get a diagram of the actual mechanism. I had another trip assembly which also had broken in the same way and had been repaired by a machinist. After installing the replacement trip assembly and the foot pedal mechanism, the press seems to be back in operation.
The spacer I found near the press is apparently not related to this problem.
I’m traveling without a laptop, but will look for photos on Tuesday. I will also alert other old style No. 4 owners to this post.