Yale Double Pin Dial Timelock

Doug MacQueen

Here are a few pictures of the Yale which is in dire need of cleaning. The door glass was broken long ago and it is filled with dust and lint. The 2 pictures of the complete one are a different timelock owned by a collector and just for reference. I have never actually studied the mechanism of the Yale but now that I have one, it is time. The left hand movement has been stripped down to show the timing mechanism of the gear train and escapement. Power supplied by the coil spring held under the large gear on the left. Reduction of power through the gear train and then the timed release by the escapement, which is mounted on it’s own separate plate. This is typical of all the modern timelocks I have worked on, so I though I would show this first. I will post some more pictures of the other aspects and features as I clean and study it further.

Doug MacQueen

In this group of pics you can see the coiled flat spring which supplies the power to the lock. It is held in the round case visible in of the previous pictures posted. In another, the click stop mechanism can be seen. This allows the coiled spring to be wound up, storing the energy. It cannot be seen at all when the lock is assembled and sits right atop the spring itself. When assembled, the winding shaft engages the inner end of the spring by a protruding notch which I see now I failed to show when I took the picture. It is on the back side of the shaft. In the third picture is the Geneva stop which is located on the outer backside of the spring housing. All except one of the “teeth” are concave on this geared wheel, which just freewheels, being attached to the case by a shoulder screw. The one convex tooth will stop the wheel from turning in turn stopping the winding shaft. This acts to limit the maximum turns that can be applied to the movement preventing overwinding the spring as well as limiting or rather preventing the spring from fully unwinding. This is known as reserve power, supplying the necessary pressure to ensure unlocking.

Doug MacQueen

Here I have removed the “fancy ” stuff from the timelock. With those parts removed it is now a standard 2 movement 72 hour timelock. Wind it up and it will unlock only after the dials come to “0” hours. There is a pin located under the “68” hour mark on each dial. The the split wishbone linkage rides on the pins until it moves out of the way, releasing the little spur catch seen in closeup. Strangely enough I found the patent for this part of the mechanism was not included in the original patent for the timelock.

Doug MacQueen

here are the pics

Dean Nickel

Very nice! :8)::8):

Doug MacQueen

This is one of two 24 hour pin wheels removed. On the underside you can see the double gear which mates up to the freewheeling double gear mounted to the lock case. This gearing arrangement is for the Sunday attachment shield which makes one revolution for every 7 revolutions the pin wheel makes. In the other picture you can see the tiny teeth on both the pin wheel and the underside of the round disc which sits on the wheel. Loosening the small central thumbscrew (not shown here) allows these two parts to separate enough to allow the pin wheel to be set to the proper time of day. The screwdriver is pointing to the large gear in the case which rotates the pin wheel. Confused yet. Any Questions?

Doug MacQueen

Here are pictures of the pin dials and related parts removed. I had to make the little spanner to remove the round nuts that secure each pin wheel. The tiny screw pictured is not part of this assembly but I included it to show how small they get on this timelock. These little buggers are found on the winding shaft ferrules.

Doug MacQueen

In a timelock this old it was not surprising that many of the pins or buttons were difficult to move in and out. Pulling them out would set the open times of the lock. Not until I started to work on freeing them up did I find out that certain ones would not pull out even though they were not frozen in place. The night hours of 10 through 4 am are not designed to be pulled out without releasing their set pins by hand. This is accomplished with a thin probe through the side holes in the wheel. It appears these specially designed pins were a little extra protection against what was had become a fairly popular threat by the late 1800’s. The application of a large amount of dynamite would be placed against the door in the hopes of breaking or at least causing the immediate release of the timelock. The lack of a bevel on these special pins would prevent them from popping out, keeping the door secure.