Generating force to cap beer bottle

[Jed MartensParticipant @jedmartens56976]

OK, something a little different for a Friday evening…

I've been reading here about capping beer bottles using a pneumatic cylinder…

pneumatic beer bottle capper

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…

Jed

[Jed MartensParticipant @jedmartens56976]

[Grizzly bearParticipant @grizzlybear]

How about a small hydraulic press?

Bear..

[Jed MartensParticipant @jedmartens56976]

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 DaymanParticipant @jeffdayman43397]

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 yetParticipant @notdoneityet]

Posted by Grizzly bear on 12/06/2020 22:21:27:

How about a small hydraulic press?

Bear..

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 LousickParticipant @paullousick59116]

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.

[HopperParticipant @hopper]

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 HaineParticipant @johnhaine32865]

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 1Participant @josephnoci1]

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 1Participant @martinperman1]

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.

Martin P

[larry phelan 1Participant @larryphelan1]

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 WyattModerator @neilwyatt]

Very good.

But true genius in engineering is something to REMOVE the caps from beer bottles with minimal effort

Neil

[Neil WyattModerator @neilwyatt]

Posted by larry phelan 1 on 13/06/2020 09:02:53:

I would be more interested in how to open the bottle when one cannot find an opener and one has few good teeth left ??

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 RogersParticipant @leerogers95060]

Posted by Neil Wyatt on 13/06/2020 09:13:15:

Posted by larry phelan 1 on 13/06/2020 09:02:53:

I would be more interested in how to open the bottle when one cannot find an opener and one has few good teeth left ??

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.

I spent many years working with French lads as a chef , the one skill that national service gave all of them was how to open a beer bottle with their teeth.

[DMBParticipant @dmb]

Plain ol' bottle opener is the most important 'spanner' in the toolbox!

[SillyOldDufferModerator @sillyoldduffer]

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'.

Dave

¹ Is Budweiser beer or not? Discuss…

[Robert Atkinson 2Participant @robertatkinson2]

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.
You can even use the park switch on the motor to run a single cycle everytime you press a foot switch. Most will give a choice of speed too.

Robert G8RPI

Edited By Robert Atkinson 2 on 13/06/2020 10:42:31

[HopperParticipant @hopper]

Posted by SillyOldDuffer on 13/06/2020 09:54:56:

… drink half the beer,…

 

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

[HopperParticipant @hopper]

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.

[Nick WheelerParticipant @nickwheeler]

Posted by John Haine on 13/06/2020 07:03:32:

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.

Exactly.

Mine was about £8 with 100 caps. Takes a couple of seconds per bottle and barely any effort.

[DanielParticipant @daniel]

I do have to concur with many above posts; my primary concern remains that of cap removal.

If you really must close a bottle, then I think Robert Atkinson is onto something fun and interesting,

and could lend itself well to (semi) automation.

I like automats.

ATB,

Daniel

[Brian GParticipant @briang]

The simplest way to get hands-free operation is probably to add a return spring and connect the hand press to a pedal. Industrial staplers often just use a length of chain for this.

For powered operation, If a windscreen wiper motor isn't powerful enough you could try a mechanism I encountered on a small powered notcher. A pedal pushed the crank that operated the notcher into a continuously rotating flywheel, engaging a gab. As the notcher reached the top of the stroke a cam pushed crank out of engagement, and unless the pedal was held down it stopped after one cycle. With this mechanism the motor ran continuously, making the choice of motors simpler

Brian G

[Jed MartensParticipant @jedmartens56976]

Thanks for the replies, I should have provided a little background. My wife operates a (very) small microbrewery. Years ago I built a semi-automatic bottle filling machine. This uses load-cells to detect fill-level, solenoid valves to stop/start the flow of beer to the filling heads, and peristaltic pumps (driven by stepper motors) to dose each bottle with priming sugar and bottling yeast.

The machine has 4 filling heads, but my wife normally only runs it with two heads operating, as she is still manually capping each bottle. So capping is the bottle-neck (pun intended).

The wee hand-held cappers are great for a batch of home-brew, but something less manual would help a lot in this case.

Regarding the speed when using a geared motor, as long as the capping operation is faster than the filling operation (around 15s) then it will be fine.

The suggestion of using windscreen wiper motors is very interesting. It essentially has the gearbox built in. A quick google showed that some claim to deliver 40Nm of torque, which should be plenty. Are these kind of motors reversible?

To those saying "use pneumatics" I have to say I agree with you! But I'd like to investigate the electro-mechanical options first, as the existing machine already uses steppers and relays and such.

Jed

[Robert Atkinson 2Participant @robertatkinson2]

American "screw-top" beer bottlles are really "twist-off". They are still crown caps like traditional bottles and put on the same way. The difference is in the neck of the bottle.

Robert G8RPI.

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