[GreenKeys] M28 to M14 TD adapter

[epvgk at limpoc.com]

On Fri, Jan 15, 2016 at 03:00:41PM -0500, Roy Morgan wrote:
> Nick,
> 
> There is a base unit that would be bolted to the table that accepts the bottom most plate of the thing you show, and had the mating sliding contacts shown in your second picture.  The base was fitted with some sort of switch that closed the loop contacts when you took the T/D out, so that the loop in which the T/D was operating would continue to be continuous.
> 
> If a T/D was malfunctioning or was due for service, it would take only seconds to remove it and replace it with another one.  I am pretty sure that the line closing contacts were arranged so that the loop was never open even during removal or installation of the T/D.   (Looping jacks in patch panels do this.) The pictures I have here of Model 14 T/Ds show a finger hold place at the very bottom of the tape end that lets you get a good grip on the machine, lift it up and pull it out of the base unit.  Once a T/D is settled onto its base, both the mechanical dimensions of the base and bottom plate, and the weight of the machine ensure it will stay put.


I have a couple of them, and yes the contacts are arranged to close the loop when                                              
the TD unit is removed - when you put it in place, it goes in at a sort of angle;                                              
the contacts on the base are a pair, like switch contacts, and the fingers on the TD                                           
itself slide under them. When the TD is sitting flat in position, its contact fingers                                          
push upward on the upper of the base contacts, lifting them off the shorter, bottom                                            
shorting contacts. Unless they're bent, or dirty, or misaligned, or there's some dirt                                          
there, etc. :)               

If someone needs my extra TD/base combo, it is available to a good home, but as usual, 
it's heavy and hard to ship safely. I'm in San Francisco. 

eric