Mechanical to Pneumatic hammer conversion

[Ted Ewert]

I was going to build a whole new hammer, but I decided to convert my mechanical hammer instead. I'm using a timer relay and a solenoid valve to control the hammer. It's actually a pretty simple setup and a flexible way to accomplish what I need.

I've been working on this project for the last month or so, trying to learn about pneumatic parts and how they all work together. I knew very little before I started, but found it interesting once the picture became a bit clearer. What I came up with is basic enough to convert most mechanical hammers to pneumatic.

I started off by stripping the hammer down to bare bones. I removed the motor and mounts, as well as the cam mounts and the rocker arm assembly. I reinforced the center column since it was going to be taking on a large off-center load. I then started adding components.

I made a couple of videos of the process. I'm learning to edit so they're a little rough around the edges. I spent over 30 years working at a TV station, much of it spent repairing editing equipment, but I never actually learned how to do it. It's kinda fun.

 

https://youtu.be/wDuEiDpRFHk

https://youtu.be/gJhNIRmLvcE

[Ted Ewert]

I have the first version done. The timer has worked as expected and provides a variety of operational modes.

As you can see it has a dial to vary the speed of oscillation. The numbers represent multipliers of the selectable unit at the bottom, in this case .1 second. This makes it easy to adjust the speed of oscillation for your particular needs. 

The timer has 4 modes, two of which I find useful. It has a one shot mode for a single firing of the cylinder. The ram is held up until the start button is pushed. The cylinder is then activated for one cycle, at the rate set on the dial. The other mode is called the flicker mode. This is a continual cycle mode which can be halted and restarted by the reset button. I have added a switch on my flow control valve which shuts off the cycle when the treadle is released. The ram then defaults to the up position and is held there until the treadle is depressed. This saves air between operations. 

This is a picture of the valve and the switch. I cobbled together a mount for the valve, which is epoxied in place, which works well. 

I built the control box as an experimental platform to explore how this timer works. It could certainly be condensed into a smaller package.

Here's a pic of the hammer as it stands:

The cylinder is attached to the ram guide and bolted to the ram. I still have to cut off the roller assembly.

That's it in a nutshell. The hammer now hits a lot harder than it did before, as well as being more versatile and controllable. This simple conversion can be done on almost any type of mechanical hammer. The videos I posted above show some of the construction and early testing if you're interested.

[Ted Ewert]

I made a few more modifications, namely to make it easier to switch between one shot mode and repetitive mode. All the control is now attached to the treadle. 

[j.w.s.]

Ted, I've seen your hammer in operation before (yeah, I'm at least one of your 51 views) - I know you've got your own reasons for converting so I won't ask the why question but I will say that your original cam design seemed to work pretty well. I've never been a fan of the Rusty style hammers just because of their foot print in the shop, but you did a nice job on it. Could have doubled the weight of the build and braced it up a bit more to stop some of the play though from what I remember on one of your earlier videos. Did you take one or two down, I thought there were a few more earlier versions? Either way have fun with the build. You're definitely adding some complications to the mix with the relays, I hope it works out to your liking! Personally I just finished taking a bull inspired pneumatic I made a few years back and converted it to a mechanical hammer, so we're heading in opposite directions on the line. Good luck, I look forward. to seeing some more videos in operation.

-J

ps, can't see the video up above there but I assume that's the latest on on youtube.

[Ted Ewert]

Update.  I finally have this hammer working just as I want it to. I shortened the stroke to 8 inches, lightened the ram to 35 lbs, and built a number of dies.

I get better performance out of the 35 lb ram due to the increased velocity. It's also more controllable with my particular set-up 

I just added a spring bumper to cushion the top of the stroke.