Jack 20ts

 

Some dimensions and pictures from Per's jack and two versions in the La Gleize museum

- Total weight = 60.5KG
- The maximum range of the jack is 343mm
- You get the max. range with 130 turns of the swing arm.
- The cams on the foot are 26.5mm apart, this means that the full range of the jack is 343 / 26.5 = 13 cams.
- This means the jack has a total reduction of 10:1
- The swing arm moves pi x 2 x 300mm = 1885mm per turn.
    1885mm x 130turns = 245050mm
    The maximum range of the jack is 343mm
    245050 / 343 = 714.5
    20000 / 714.5 = 28
    You'll have to pull on the handle bar with 28Kg to lift 20000Kg with this jack!

Click on the image to open the larger printable file (57.2KB)

Click on the image to open the larger printable file (56.9KB)

I did not take the cams off the axle, since I couldn't risk damaging this piece of antique. So I could not draw how the cams were fixed to the axle. We have some indication how this was done: On the sides of the cams, you find 30° angles. The cams are placed together with pieces of leather between them. This probably means that only the ring on the right was fixed to the swing arm axle somehow and the cams with the leather in between are only pressed against that ring in order to fix them to it.

The below pictures were taken in the "La Gleize" museum in November 2003.

v01

v02

v03

v04

h01

h02

h03

h04

v05

v06

v07

h05

h06

h07

h08

There is another jack in the museum. Unfortunately it is inside a diorama, so I don't have clear pictures of it. You can see it differs from the other one on several points:
- It has a "crown" top instead of a flat one.
- The axles plate is ribbed.
- There is a smaller diameter handle bar on the swing arm. It is possible, this one is not foldable.

a1

a2