Doug MacQueen wroteYou are really making me work for this. K series are medium sized models. M and N are large ones.
I’m sorry, I’m not trying to be difficult or argumentative & I really appreciate the replies. Whether I am right or wrong we are talking across purposes. Maybe I am not explaining myself clearly.
I am not referring to the K series time locks that use smaller L size movements.
As I understand it, the M series time locks were available with or without what is called the “Open Attachment”.
The top two time locks A & B in the following link (http://www.my-time-machines.net/yale4mvt.htm) are described as Quad-Ms, and have the open attachment & it occupies the area to the right of the movements. The open attachment is described and discussed in their description.
The third lock pictured, “C” is shorter than “A” & “B”, because it lacks the open attachment. The description for this lock states that it is a Quad-M, that has been retrofitted with L size movements.
If you look at the catalogue page you posted, it states clearly that the picture is of a regular Quadruple-M. Below the picture, it provides measurements for two Quadruple-M series time locks. The regular, and a Style K4 Quad-M (not K movements), that lacks the open attachment.
I understand that a series N lock uses M size movements & is designed to operate an automatic bolt motor and it seems that it has a very similar shape to a type M that lacks the open attachment.
Thankyou for your patience.
…Mark
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