|Jed Martens||12/06/2020 22:02:12|
84 forum posts
OK, something a little different for a Friday evening...
I've been reading here about capping beer bottles using a pneumatic cylinder...
To give you an idea of the kind of thing being used to do this...
It is stated that the force required is "314 pounds" (100 PSI acting on a 2" bore cylinder). I'll take this as being 142kgf, or ~1400N.
All well and good, but I have no experience with pneumatics and no air compressor. I'm wondering if some electro-mechanical contrivance might work?
Consider a stepper motor generating 1Nm of torque (there may be much better motors for this job, but I've only ever played with steppers). A module 1 20 tooth spur gear mounted to this (driving a rack, for example), would generate a force of 100N, as the edge of the gear is 0.01m from the centre (length x force = torque).
This isn't enough, but we can of course use gears to reduce the rpm but increase the torque. A 14:1 gearbox would get us there.
I think the reduction in RPM is ok. The capper does not need to actuate very quickly, and provided the stepper can deliver maximum torque at 60rpm (datasheets I've looked at suggest this is ok) then I think the operation could be completed in a few seconds.
I'm pretty new to this - are there any obvious errors in my thinking above? What I don't have a feel for is whether small module 1 gears can be expected to carry these kinds of forces. Larger gears would be probably result in a solution that was too large (compared to the pneumatic cylinders anyway, which are probably the sensible way of tackling this...). Also, I would guess a 14:1 reduction would need a 2-stage gearbox...
|Grizzly bear||12/06/2020 22:21:27|
|250 forum posts|
How about a small hydraulic press?
|Jed Martens||12/06/2020 22:24:49|
84 forum posts
Hydraulics are even further out of my comfort zone than pneumatics! The long-term aim here would be to introduce a degree of automation. It's easy enough to control a stepper, and I can almost see how it could be approached with a pneumatic cylinder. But I wouldn't know where to start with a hydraulic system...
|Jeff Dayman||12/06/2020 22:48:00|
|1854 forum posts|
The ancient and humble straight line action toggle clamp comes to mind. They are available from many makers in forces from a few pounds to 800 pounds force. Simple mechanical devices that last a while and do not cost much. A good brand is De-Sta-Co. Google is your friend. McMaster Carr have accurate CAD models of many.
Fine adjustment of position of delivered force can be easily done with a screw and nut adjuster in the end of the clamp plunger attaching to whatever "pusher" piece you are using.
Note - if applying high forces to glass bottles it is a good idea to hold them dead square to the force applied and hold them firmly. Otherwise the device becomes a bottle neck breaker rather than a bottle capper.
|not done it yet||12/06/2020 23:32:56|
|4900 forum posts|
Pneumatics is much faster than hydraulics, otherwise very similar. Much of the force is to crimp the cap radially, once pressed firmly in position. Hydraulics tend to operate at far higher pressures than air pressure.
|Paul Lousick||13/06/2020 00:13:03|
|1501 forum posts|
142kgf to is a small load. Some of us weigh that much. Hydraulics would crush the bottle ?
Whats wrong with the inexpensive hand press for capping bottles ? Quick, easy and available on ebay for about $30.
Or make an adaptor to fit the bottle cap and use a drill press.
4784 forum posts
You might get a 240 volt solenoid that would do the job.
Stepper motor geared down sounds really slow. A few seconds per cap will add up very quickly on a production run.
A solenoid and a foot switch would be way faster . Although a hand operated switch would keep fingers away from the danger zone at the critical moment.
|John Haine||13/06/2020 07:03:32|
|3273 forum posts|
Goog grief! I bought a small gadget from Boots with the closer on a small wooden handle sticking out the side, you put the cap blank on the bottle, the gadget on top, and gave it a smart blow with a mallet. Never broke a bottle, worked fine.
|Joseph Noci 1||13/06/2020 07:48:42|
|739 forum posts|
I doubt a solenoid would do it...
Crudely, a solenoid with a 100mm diameter core, 1000 turns with 10 amps flowing, with a 0.1mm gaps tween core and coil, would create a force of roughly 600N, and that only when the core is almost fully in the coil. Also, the nature of solenoids is to result in a snap action, which may just shatter the bottle. And you cannot retract the die from the cap with the solenoid, so you need a powerful retract spring and now the solenoid needs to overcome that force as well.
Linear motor operated 'solenoids' are common - using a leadscrew and gearbox, and available on Ebay , etc - even an old motor-gate actuator would worm, albeit a bit large.
I still think the proven method, pneumatic, is the best.
There were some suggestion of manual methods, although Jed did state he was trying to automate the process..But what about using that manual press , with a small motorised gearbox, and a crank driving the end of the handle of the manual press - the motor could just go round all the time, and on the up stroke the operator removes the corked bottle an inserts the new one..No imbibing on the job lest you lose sync though..
|martin perman||13/06/2020 09:02:11|
1860 forum posts
Automation systems tend to use Pneumatics or hydraulics because they are, relatively speaking, quick, efficient, cheap and easy to use, there is normally only two sensors on a cylinder so electrically simple as well and the force required can be easily obtained, as they say no point re inventing the wheel, when building the unit you may find the the cost of a compressor, a couple of valves and a cylinder would out way that of the controls, gearbox, motor and time required to get a different method working.
|larry phelan 1||13/06/2020 09:02:53|
|806 forum posts|
I would be more interested in how to open the bottle when one cannot find an opener and one has few good teeth left ??
|Neil Wyatt||13/06/2020 09:12:00|
18141 forum posts
But true genius in engineering is something to REMOVE the caps from beer bottles with minimal effort
|Neil Wyatt||13/06/2020 09:13:15|
18141 forum posts
Head of a key and sore thumb, or more risky hook on the edge of brick and well-judged blow with the heel of your hand.
|Lee Rogers||13/06/2020 09:20:05|
70 forum posts
|1012 forum posts|
Plain ol' bottle opener is the most important 'spanner' in the toolbox!
6194 forum posts
Last time I opened a Budweiser the cap looked just like a press-fit type (and could be removed with an ordinary bottle opener), but was really a short screw thread. Possible to unscrew the cap, drink half the beer¹, and replace the cap to finish it later.
Not sure what the idea is. Maybe its so drunks sans bottle-opener can still get to the booze. Except Mr Blotto has to know Budweiser caps can be unscrewed - the whole concept flies in the face of 'common sense'.
¹ Is Budweiser beer or not? Discuss...
|Robert Atkinson 2||13/06/2020 10:41:38|
755 forum posts
I'd go for off the shelf bottle cappping machine, windscreen wiper motor and a spring. Have a number of spring attachment points on the lever to change applied force.
Edited By Robert Atkinson 2 on 13/06/2020 10:42:31
4784 forum posts
What is this alien concept of which you speak?
I think most/many US beers have screw tops. Maybe because dental repairs are so expensive over there? Or just convenience, you know like drive through wedding chapels and microwave popcorn.
Edited By Hopper on 13/06/2020 10:59:54
4784 forum posts
Well if you were using the slower stepper motor model, you could make it to cap two or four bottles at a time to up the pace.
|Nicholas Wheeler 1||13/06/2020 11:31:04|
|362 forum posts|
Mine was about £8 with 100 caps. Takes a couple of seconds per bottle and barely any effort.
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