LeCoultre – Bumper – Cal. 481
I bought this LeCoultre Bumper watch to put up on my sale site. The movement really needed a servicing and the case badly needed some polishing, as well as the usual changing the mainspring and crystal. These Jaeger LeCoultre Bumper watches are absolute classics.
This particular movement is a Cal. 481 bumper movement. They were originally designed in the late 40’s to mid 50’s. Beating at 18,000 A/H.
Here are a few before pictures. As you can see, someone previously did a lot of damage trying to open the screwdown case back. I’ll polish most of that off.
A few more close-ups before opening it up.
Now it’s time to dig in and get my hands dirty 🙂
The dial has such a classic handsome design.
This is the dial-side of the watch with the dial clearly removed. The power-reserve indicator is actually quite a clever simple design. I love stuff like this.
Next, I flip the movement over to the bridge side and remove the oscillating weight.
Revealing a very interesting design for winding the watch via the oscillating weight. If you look at the center of the watch in the next image, you will see the ratchet teeth that intertwine with the pinion of the oscillating weight.
With the oscillating weight disassembled, you can see that one side of the weight has a spring, and the other spring is actually located on the movement itself.
Here is the mechanism that does all the work. Long story short, the weight turns on it’s axis, each rotation moves the teeth on the lever which in turn rotates this mechanism which again, in turn then winds the mainspring.
Just a few shots with the oscillating weight removed.