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My next inline treadle hammer design


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Charlie, I was really fascinated with your analysis on inline treadle hammer design. I didn't understand most of it, but truly appreciated the effort that you put into it. What intrigued me even more was that BEAUTIFUL model you made. Is it possible that you could send me a dimensioned drawing of the model so that I might better understand the workings of the linkage, particularly the elliptical elements. I am new to this forum and only yesterday saw your post. I have worked as a welder/fabricator for the past 42 years and am planning to retire in June. I have built some rather complex industrial machinery in that time (INCLUDING THE DRILL RIG THAT HELP FREE 33 MINERS IN CHILE BACK IN 2010) so I CAN READ DRAWINGS AND BLUEPRINTS. Thanks, Charlie.    ---- Peter

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  • 2 weeks later...

Peter, Thanks for your interest in my optimization of JasonM's original post.  I don't have any dimensioned drawings for the entire treadle hammer, except for the free-body diagrams of the Hoecken's mechanism, as the rest of the treadle hammer would need to be sized according to the user.  (I'm 6'-2" tall and what would be comfortable for me for the type of use I would want for this hammer might not fit the needs of most others).  The wooden prototype that I threw together was aproximately 1/2 scale, and was mostly just cut on the fly - no drawing for the frame (only the Hoecken's mechanism).  As in the PM I sent you, I will look about my boxes some time over the next two weeks and dig out these drawings and calculations and forward to you what might be useable or readable (I tend to do a lot of margin scribling and doodling on my drawings while I'm thinking, so I'll probaly not send much of that).  But If I recall most, if not all, of the critical size ratios for the linkage is shown in one or two of the pictures I inserted in my original post. 

 

Tubbe, I'd be interested in what the arm and linkage ratios were that you used (Maybe I'll try to scale them off your lego mock-up).  Placement of the ram pivot points in front of the ram would make for a more compact hammer mechanism, but the drive link operating within the space of the throat (space between the ram, or anvil, and the column) reduces again your available working space if one where workiing a larger piece.  (it's all a trade-off no matter how it is designed).  I'll be interested in doing some calcuations to see if your optimization of the linkages maintains as straight a line as the Hoecken's.  At first glance I like what you did, but I fear that the change in geometry and pivot rotation points will cause some front to back oscillations.  What was your expected ram travel for a specified arm length?   

 

-Charlie 

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  • 2 weeks later...

Hi Charlie. I think you can make out the linkage ratios from the "lego video" (counting holes). Small top connected at 3 and the rest is spaced 6. So the ratio is 1:2 on the pivots. The motion is exactly as the Hoecken's I believe. I have analyzed the motion in my 3d package and the travel is very linear. Near the top of the stroke it is off by 0,5% or so. The total ram travel is relative to the link lengths of cause; in my 3d model I made the travel 40cm if I remember right.

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Not sure if any body is still interested in this discussion but I ran across this Whitworth quick return mechanism that I thought would be an excellent way to power this style of hammer. I have studied both hammer types shown in this thread and believe this could work on both types of hammers to power them the very first mechanism in the video is the variation I would use. I do not have the program to draw this. If you mount the mechanism with the small red arm down and mount the yellow arm in line with the back on a brace mounted between the anvil and the back post and connect the green slide to the bottom arm  with the style that has the round sprocket  you should be able to use the very bottom red linkage shaft to connect it with a key way and a pulley on the back side to connect a motor to the bottom section and it will look similar to the linkage on a train wheel while in motion it should in theory travel up and down pushing the mechanism up and down continually. Then on the other style where the pedal linkage arm goes you could mount this set up the same way and the green part would connect it with a small pivot arm to go from the green part to the small grey arm to simulate pulling it up and down with the foot pedal. If the blue arm was a turnbuckle you could adjust it to where it has the right travel to get the proper up and down motion. I can hand draw what I am talking about but not sure how well it would show up. I believe you could have the motor on a pivot like the tire hammer to add tension to the hammer when you want to use the motor and it would run until you pressed down to tension the belt.

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