KMZ DRUG

See the basis Canon Vt - pictures from Cameraquest.


http://www.ussrphoto.com/UserContent/722015_canos Vt.png

Yes Luiz, this the Canon Jacques referred to- I think. I never owned one, but I suppose it's like Jacgues says- triggers share a common "issue"- stiffness.
Leicavit on the other hand is an add-on type (or so I've read in the forums) and that may be the reason why they wind smoother. Apart from the legendary build quality.

Milo- you're right, my repairman said that Drug shutter is like the one in early Prakticas. The word 'early' somehow slipped my mind, or I didn't think of it as important. Now that you mention it, it surely is. I don't know how either of the shutter mechanism looks like. But one day.....

Excuse but all Prakticas since the beginning have a different mechanics they are similar to Edixas and in reverse sense of Exaktas

Droug is much simpler and has a reverssed Zorki lay-out
Regards
LP

Excuse but all Prakticas since the beginning have a different mechanics they are similar to Edixas and in reverse sense of Exaktas

Droug is much simpler and has a reverssed Zorki lay-out
Regards
LP

in order to see Drug mechanics go to

http://rangefinder.ru/club/viewtopic.php?f=5&t=8056
http://rangefinder.ru/club/viewtopic.php?f=5&t=8056&start=20
http://rangefinder.ru/club/viewtopic.php?f=5&t=8056&start=40
http://rangefinder.ru/club/viewtopic.php?f=5&t=8056&start=60

Regards
LP

Wow Luiz,
You are a wealth of info.
Thanks for the clarification!

Regards,
Marko

Here the winding mechanim od Canon VI-T (also V-T)
extremely similar to Droug


http://www.ussrphoto.com/UserContent/1522015_canon VI T winding mechanism.png

Regards
LP

quote:

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Originally posted by Luiz Paracampo

Here the winding mechanim od Canon VI-T (also V-T)
extremely similar to Droug

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Thank you Luiz,
similar but very different. The Canon has only one chain wheel and the trigger pulls to the other direction. That's much better because the additional chain wheel of the Droug is even smaller and takes much energy. The Canon should work much better.

I wonder which construction is older, the Canon or the Droug.

Jacques said that his Canon had the same winding problem as Drug. Maybe one or two wheels doesn't have that much influence on the force needed to wind. Leicavit on the other hand is reported to operate smoothly. But Leicavit is an add-on, not built-in like in Canon VI-T or Drug. Maybe that is the reason for smoother operation, or some other construction finesse that Leice used, like ball-bearings, etc.

It's the friction between the plates of the chain. When new it was working but after years without oil the friction can be too much and the smaller the chain-wheels are the more friction you will get. The second chain-wheel of the Droug is very small.
The Leicavit has one advantage, the body is much bigger. If Leica used a chain also, their chain could be bigger. There could be a spacer between the chain-plates which will bring the friction down. These spacers could be made of copper or could have special coatings. For Droug and Canon it was important to keep the body small.
Canon's advantage is their reverse system, only one chain-wheel needed. I can even think of a reverse system without a chain.

Now, after watching Ulrich's photos of his Drougs again in the other thread, I see that only the Droug had a reverse system and instead the Canon had a normal system and the Leicavit must be a normal system either because it's a add-on. So why was a reverse system needed for the Droug?

If the Drug had a "normal winding system" this would be a left side winding system.like Exakta
the bottom trigger forces the film advance lay-out to be that way.
The presence of the two gears in no way makes the advance harder than the other.
Canon and Drugs suffer from stiffness and so, they were descontinued
Leicavit and Abrahamson quick advance which is a copy of RotSchild's Camcraft are slightly less brute because being a removable unit it fuctuates during advance operation and adjusts itself to the center of the shaft of main empty cвmera roll. Even so, these systems had no success at all.
Today Lomography has a four lensed plastic sequence cвmera that has a similar systemusing nylon cord instead of chain and frequently the system breaks, making the cвmera inoperable.

The Canon is a normal system (normal like a Zorki) and because of it the Canon needs only one chain-wheel. Both triggers (Canon and Droug) pull to the same side so that the left hand can be used for film advance. But because the Droug is a reverse system it needs an additional chain-wheel. I still can't understand the reason why the Droug was made as a reverse system. Makes no sense to me.

If you ride your bicycle with a dry chain the chain will make much noise because of friction. This friction will wear on the surface of the chain-plates and without oil it will get rusty and very stiff. But on a bicycle the smallest chain-wheel is still much much bigger than on a Droug and the Droug has 2 much smaller chain-wheels. I'm sure, after years without service the Droug chain can't be working smooth.

Why even have all the hazzle with the chain when you can have a wind-lever. A wind-lever which rotates only must not be slower to operate than a trigger which pulls to the side. There were Prakticas which had the wind-lever on the bottom to be used with the left hand. For these Prakitcas their reverse system made sense (reverse to Zorkis). Wind with the left hand and shoot with the right hand. Simple technic and much better. This would have been a nice idea for a Zorki-7, fast, small body and not expensive.

I don't know how the system looks on Prakticas but I have an Agfa Flexilette that employes a wind lever on the gottom that one has to drive with the left thumb to wind the film. A very easy operation to be honest. And it winds from right to left- the reverse way...