    
Bob uk
Unregistered guest
Posted From: 94.197.122.88
| | Posted on Wednesday, 03 September, 2014 - 07:40: |    |
Today I designed a ram to push off a drive flange from a shaft. Wood ruff key and 5 degree taper. It is a drive shaft for a big mortice and tennon machine used for oak framed buildings. It's got 3" square chisels. Once the drive flange is off then the bearing can be replaced and the carpenters wrists will feel better.
The puller is a Churchill screw type.
The ram is 3" long and 2" dia with a o ring half way down sitting 5 thou proud.
The cylinder is 3" dia and 4" long. With a 10 degree lead in a 2" bore plus 2 thou" clearance. The lead is 1/4" into the bore so that the piston and o ring don't catch and tear the o ring.
In the closed end of the cylinder side is a M10 tapped hole and a M10 bolt.
The cylinder is filled with chassis grease.
When the bolt is screwed in it takes up volume which forces the piston out. Because the flange to be pulled is on a taper, it only needs to move a couple of thou" for the drive flange to release. The plan is to put the ram between the puller screw and the shaft end. Tighten the puller screw up solid then screw the M10 bolt in and hit the end of the puller jacking screw with a 4 lb lump hammer to shock the taper.
I have made these before and they work well but eventually strip the thread. Making the thread the next size up lowers the ratio. After about 2 repairs the ram is scrap. On've I made one and for an o ring I used a bead or rtv silicon waited till it was set and forced the piston in with a vice. It worked for a while then the seal come out with a thin curtain of grease behind it.
If the ram doesn't work then the machine will have to be dismantled which is going to a load of Work.
Also a brake caliper can be used by fitting a grease nipple and pumping the gun.
Sometimes when greasing old type of king pins the vehicle will lift under the pressure of the grease on the thrust brgs.
(Message approved by david_gore) |