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<p>[QUOTE="dcarr, post: 26299120, member: 4781"]A few weeks ago I posted some info and pictures related to my coin press malfunctioning.</p><p><br /></p><p>After further use of the press, it became obvious that there were still some issues. Now that I know more, everything I had worked on previously was related to the ejection system. That system WAS fixed, but there were other problems lurking ...</p><p><br /></p><p>The mysterious "Clutch Valve Failure" fault seemed to be fixed when I repaired the ejection system. But the problem became more frequent and harder to get past as I used the press more. Eventually, I could not get the press to run at all.</p><p><br /></p><p>For a while, every time I had that fault, I would shut down the press and fiddle with the ejection system. Upon starting back up again, the press would work. But only for a shorter and shorter time in each instance. In every case, sooner or later, pushing the "two-hand" buttons to initiate a strike would result in the fault and the press would stop moving right in the middle of the striking. Eventually, I could net get the press to move AT ALL, no matter what I did.</p><p><br /></p><p>I began to realize that the "Clutch Valve Failure" was related to something other than the ejection system. I surmised that the reason the press would work for a short time after starting it up was that it functioned when "cold", but would fail when warmed up some.</p><p><br /></p><p>I was going to be hosting an event for one of the local coin clubs, and I had to get this thing working right or everybody would be disappointed.</p><p><br /></p><p>What is the "Clutch Valve" (the one that was failing) ? I previously thought it was the valve that controlled the ejection system, but that was not it.</p><p><br /></p><p>Finally, I started looking at the obvious. This device (orange arrow) looked like some kind of large valve. The blue pipes are high-pressure air lines. The tan cables are electrical. This seems like an electrically (solenoid) operated air valve. It diverts air through the center shaft of the flywheel to cause a clutch to engage on the inboard side of the flywheel. Engagement of that clutch is what causes the press to move (and strike) :</p><p><br /></p><p>[ATTACH=full]1679134[/ATTACH]</p><p><br /></p><p>So it was time to take that gizmo apart and see what was going on inside it. Fortunately, it was easy to get at. Upon taking it apart I found that it contained two solenoid-controlled plungers that controlled air flow. Both plungers had silicone rubber seals. The first thing I noticed was that both had chipping around the edges. These had been in use for a long time ! :</p><p><br /></p><p>[ATTACH=full]1679135[/ATTACH]</p><p><br /></p><p>The central area does not make contact with anything. The portion of these gaskets that is outside the scribe circle (pink arrow in the image above) is the area that makes contact to seal off the air. The chipping had just started to get to the circles. I believed that they were borderline functional, and that is why it was difficult to pin down the real issue.</p><p><br /></p><p>I fabricated new gaskets out of some silicone rubber I had. After I installed them, I started up the press and pushed the two-hand buttons. The press performed a normal striking motion ! Then I pushed the buttons again to perform another normal strike. I heard the normal sounds that preceded the engagement of the clutch for striking. But then NOTHING. No striking movement at all. What the hell !</p><p><br /></p><p>I shut down the press, turned it off, then back on and started it up. The first push of the buttons resulted in a normal striking motion. The second time - nothing.</p><p><br /></p><p>I checked all the electrical connections that I could find everywhere. I investigated all sorts of things. Eventually, I got the idea to try a system reset while running. I pressed the two-hand buttons and got a normal strike. I pushed the buttons again and nothing happened. but I left the press (flywheel) running this time. Pressing the "Reset" button on the control panel did nothing because, as far as the press was concerned, there was nothing to reset. I had to give it something to reset. So I came up with the idea of triggering an over-load fault (by pushing a certain test button). Then the reset button would do something. So I did that and then when I pressed the two-hand buttons, I got a strike. Pressing the two-hand buttons again - nothing. The reset procedure allowed as many strikes in a row as I wanted. But I can't keep pushing those overload & reset buttons for every strike - that would be very inconvenient (and shouldn't be necessary).</p><p><br /></p><p>So why wasn't the press automatically resetting itself after completion of a strike cycle ? It did before I worked on the clutch valve, why not now !!? I rebuilt the clutch valve again - no difference.</p><p><br /></p><p>I thought about it for a while and inspected the timing mechanism inside the right side of the press. I found nothing there. While still thinking about the issue, I decided to take a break from that and inspect an area on the left side of the press where I had previously repaired a small oil leak. That oil leak was stopped (for the most part). But at that point I happened to notice a device (switch) that was nearby. This switch has a roller wheel that rides on a ledge. When the frame rail moves up and down (for striking), the ledge moves as well and the switch is activated. Maybe the switch was bad ?</p><p><br /></p><p>So for my next test, I started the press and did one strike. Pushing the two-hand buttons again did nothing. But at that point I went around to the roller switch and lifted it up. At that point I heard a click inside the electrical cabinet (an electrical relay had tripped). After that, pushing the two-hand buttons was successful in causing another strike. The roller switch position is adjustable by loosening the set screw. (light green arrow):</p><p> [ATTACH=full]1679136[/ATTACH]</p><p><br /></p><p>I used the press for 17 years and never touched this switch. The set screw was still tight. But now that I have repaired some faulty systems on the press suddenly it needs adjustment, even though I never touched it !!? I can't explain why it needed adjustment at this time. But I set the position and everything worked !</p><p><br /></p><p>I then proceeded with producing an order of nearly 1,000 pieces. I struck 950 of them with no press issues whatsoever. Then, suddenly, a loud sound THWAT-THWAT-THWAT-THWAT ... etc. I immediately shut down. It sounded bad.</p><p><br /></p><p>I checked the motor, flywheel belts, etc. I found nothing wrong. So I started the flywheel again. The same alarming sound started immediately. This time I left it running while I looked and listened closely (and carefully - being close to the spinning flywheel is intimidating). Soon I put my hand on the device that is mounted on the end of the motor shaft (see the GREEN arrow in the first image above). The device was vibrating badly. I was pretty sure it was the culprit. So I shut down the press and started removing the device. It is apparently an RPM speed switch. Below a certain RPM threshold, the switch is electrically closed. Above that RPM, the switch opens. One function of the switch is to prevent restarting of the motor unless the motor RPM is below a certain threshold. The actual RPM threshold is adjustable via external set screws on either side of the device.</p><p><br /></p><p>Upon removing the device from the motor shaft, a washer fell out, but I couldn't tell from where. I took the device apart and rebuilt it. I did not find anything obviously wrong. But, upon reinstalling it, I found that the rubber buffer that fits in the universal connecting joint on the shaft looked defective. It should be in the shape of an "X". But two wings of it were missing (see yellow arrows):</p><p><br /></p><p>[ATTACH=full]1679138[/ATTACH]</p><p><br /></p><p>It seemed logical that the missing rubber pieces could cause the shaft coupler to "THWAT" repeatedly. Feeling around the oil pan below the joint I came up with the two broken pieces.</p><p><br /></p><p>I had a similar (but not exactly the same) coupler that was replaced years ago on one of my engraving machines. The coupler itself wouldn't fit. But I modified the red rubber buffer from it and put it into the old coupler on the press (the blue arrows point to three of the four ends of the "X"-shaped red-rubber buffer):</p><p><br /></p><p>[ATTACH=full]1679139[/ATTACH]</p><p><br /></p><p>After that I started the flywheel and there were no unusual noises.</p><p><br /></p><p>A couple days later I hosted the coin club striking event and there were no issues with the press.</p><p><br /></p><p>A good time was had by all. Whew ![/QUOTE]</p><p><br /></p>
[QUOTE="dcarr, post: 26299120, member: 4781"]A few weeks ago I posted some info and pictures related to my coin press malfunctioning. After further use of the press, it became obvious that there were still some issues. Now that I know more, everything I had worked on previously was related to the ejection system. That system WAS fixed, but there were other problems lurking ... The mysterious "Clutch Valve Failure" fault seemed to be fixed when I repaired the ejection system. But the problem became more frequent and harder to get past as I used the press more. Eventually, I could not get the press to run at all. For a while, every time I had that fault, I would shut down the press and fiddle with the ejection system. Upon starting back up again, the press would work. But only for a shorter and shorter time in each instance. In every case, sooner or later, pushing the "two-hand" buttons to initiate a strike would result in the fault and the press would stop moving right in the middle of the striking. Eventually, I could net get the press to move AT ALL, no matter what I did. I began to realize that the "Clutch Valve Failure" was related to something other than the ejection system. I surmised that the reason the press would work for a short time after starting it up was that it functioned when "cold", but would fail when warmed up some. I was going to be hosting an event for one of the local coin clubs, and I had to get this thing working right or everybody would be disappointed. What is the "Clutch Valve" (the one that was failing) ? I previously thought it was the valve that controlled the ejection system, but that was not it. Finally, I started looking at the obvious. This device (orange arrow) looked like some kind of large valve. The blue pipes are high-pressure air lines. The tan cables are electrical. This seems like an electrically (solenoid) operated air valve. It diverts air through the center shaft of the flywheel to cause a clutch to engage on the inboard side of the flywheel. Engagement of that clutch is what causes the press to move (and strike) : [ATTACH=full]1679134[/ATTACH] So it was time to take that gizmo apart and see what was going on inside it. Fortunately, it was easy to get at. Upon taking it apart I found that it contained two solenoid-controlled plungers that controlled air flow. Both plungers had silicone rubber seals. The first thing I noticed was that both had chipping around the edges. These had been in use for a long time ! : [ATTACH=full]1679135[/ATTACH] The central area does not make contact with anything. The portion of these gaskets that is outside the scribe circle (pink arrow in the image above) is the area that makes contact to seal off the air. The chipping had just started to get to the circles. I believed that they were borderline functional, and that is why it was difficult to pin down the real issue. I fabricated new gaskets out of some silicone rubber I had. After I installed them, I started up the press and pushed the two-hand buttons. The press performed a normal striking motion ! Then I pushed the buttons again to perform another normal strike. I heard the normal sounds that preceded the engagement of the clutch for striking. But then NOTHING. No striking movement at all. What the hell ! I shut down the press, turned it off, then back on and started it up. The first push of the buttons resulted in a normal striking motion. The second time - nothing. I checked all the electrical connections that I could find everywhere. I investigated all sorts of things. Eventually, I got the idea to try a system reset while running. I pressed the two-hand buttons and got a normal strike. I pushed the buttons again and nothing happened. but I left the press (flywheel) running this time. Pressing the "Reset" button on the control panel did nothing because, as far as the press was concerned, there was nothing to reset. I had to give it something to reset. So I came up with the idea of triggering an over-load fault (by pushing a certain test button). Then the reset button would do something. So I did that and then when I pressed the two-hand buttons, I got a strike. Pressing the two-hand buttons again - nothing. The reset procedure allowed as many strikes in a row as I wanted. But I can't keep pushing those overload & reset buttons for every strike - that would be very inconvenient (and shouldn't be necessary). So why wasn't the press automatically resetting itself after completion of a strike cycle ? It did before I worked on the clutch valve, why not now !!? I rebuilt the clutch valve again - no difference. I thought about it for a while and inspected the timing mechanism inside the right side of the press. I found nothing there. While still thinking about the issue, I decided to take a break from that and inspect an area on the left side of the press where I had previously repaired a small oil leak. That oil leak was stopped (for the most part). But at that point I happened to notice a device (switch) that was nearby. This switch has a roller wheel that rides on a ledge. When the frame rail moves up and down (for striking), the ledge moves as well and the switch is activated. Maybe the switch was bad ? So for my next test, I started the press and did one strike. Pushing the two-hand buttons again did nothing. But at that point I went around to the roller switch and lifted it up. At that point I heard a click inside the electrical cabinet (an electrical relay had tripped). After that, pushing the two-hand buttons was successful in causing another strike. The roller switch position is adjustable by loosening the set screw. (light green arrow): [ATTACH=full]1679136[/ATTACH] I used the press for 17 years and never touched this switch. The set screw was still tight. But now that I have repaired some faulty systems on the press suddenly it needs adjustment, even though I never touched it !!? I can't explain why it needed adjustment at this time. But I set the position and everything worked ! I then proceeded with producing an order of nearly 1,000 pieces. I struck 950 of them with no press issues whatsoever. Then, suddenly, a loud sound THWAT-THWAT-THWAT-THWAT ... etc. I immediately shut down. It sounded bad. I checked the motor, flywheel belts, etc. I found nothing wrong. So I started the flywheel again. The same alarming sound started immediately. This time I left it running while I looked and listened closely (and carefully - being close to the spinning flywheel is intimidating). Soon I put my hand on the device that is mounted on the end of the motor shaft (see the GREEN arrow in the first image above). The device was vibrating badly. I was pretty sure it was the culprit. So I shut down the press and started removing the device. It is apparently an RPM speed switch. Below a certain RPM threshold, the switch is electrically closed. Above that RPM, the switch opens. One function of the switch is to prevent restarting of the motor unless the motor RPM is below a certain threshold. The actual RPM threshold is adjustable via external set screws on either side of the device. Upon removing the device from the motor shaft, a washer fell out, but I couldn't tell from where. I took the device apart and rebuilt it. I did not find anything obviously wrong. But, upon reinstalling it, I found that the rubber buffer that fits in the universal connecting joint on the shaft looked defective. It should be in the shape of an "X". But two wings of it were missing (see yellow arrows): [ATTACH=full]1679138[/ATTACH] It seemed logical that the missing rubber pieces could cause the shaft coupler to "THWAT" repeatedly. Feeling around the oil pan below the joint I came up with the two broken pieces. I had a similar (but not exactly the same) coupler that was replaced years ago on one of my engraving machines. The coupler itself wouldn't fit. But I modified the red rubber buffer from it and put it into the old coupler on the press (the blue arrows point to three of the four ends of the "X"-shaped red-rubber buffer): [ATTACH=full]1679139[/ATTACH] After that I started the flywheel and there were no unusual noises. A couple days later I hosted the coin club striking event and there were no issues with the press. A good time was had by all. Whew ![/QUOTE]
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