Christie Drive
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The Christie suspension is by the American inventor J. Walter Christie in the 1920s for light tanks developed chain drive . The main feature of the design is the ability to remove the chains on paved roads and ride on the rollers , which increases range and speed and reduces wear . A - lightly armored - demonstration vehicle drove with chains at 64 km / h, while on the rollers it was 113 km / h.
construction
The Christie chain drive is a roller drive without support rollers for the overhead chain run . It has large, disc-shaped double castors , which are individually suspended on swing arms , which in turn are sprung with coil springs . The rollers are coated with rubber to reduce wear . The drive wheels are at the rear, the idlers at the front of the vehicle. The drive wheels transmit their movement to the crawler tracks via the guide teeth arranged in the middle of the chain links. When driving on the road on the rollers, the last pair of rollers is driven by a roller chain , while the first pair of rollers is steerable . So that this pair of rollers can be taken, the vehicle front is wedge-shaped. Since the coil spring for the suspension of the front pair of rollers cannot be installed vertically, as with the other rollers, Christie designed a lever deflection and arranged these two springs horizontally without having to accept any loss in off-road mobility.
The Christie drive is characterized by the fact that it can be driven with and without chains, has no support rollers, when driving on the road without crawlers, a pair of rollers is driven and the front pair of rollers can be steered and its movement is deflected from the vertical to the horizontal, all rollers individually are suspended and are sprung with (external) coil springs.
Prototypes
In 1928 Christie demonstrated his vehicle to the US Army . The USA purchased five prototypes , but could not finally decide to procure the vehicle, officially for cost reasons. Poland also ordered two vehicles, but later canceled the order.
Soviet Union
BT
In 1931 the Soviet Union acquired two chassis without towers. With the help of their American colleagues, the Soviet engineers improved Christie's design and used it under license for their light tanks of the BT series , which could still drive with or without tracks.
T-34
In the case of the T-34 , the option of wheel travel was dispensed with because more durable chains were now available and experience with the BT had shown that converting from wheel to chain travel and vice versa was too time-consuming. The disadvantages such as a more complicated construction and higher weight of the combined wheel / track drive compared to a pure track drive outweighed the advantage of the greater speed on paved roads. As a result, the complex steering of the first pair of rollers could be omitted and all coil springs could be installed almost vertically.
Great Britain
Great Britain closely followed developments in the Soviet Union and eventually used the Christie principle for its own cruiser tanks , including the following types:
literature
- Matthew Hughes, Chris Mann: T-34 tanks . Karl Müller, Erlangen 1999, ISBN 978-3-86070-799-9 (English: The T-34 tank . Translated by Jürgen Brust).
- Alexander Lüdeke : Weapons Technology in the Second World War . Infantry weapons, unarmored vehicles, armored vehicles, artillery, special weapons, aircraft, ships. Parragon Books, Bath 2007, ISBN 978-1-4054-8584-5 .
Web links
Individual evidence
- ^ J. Walter Christie: Suspension for vehicles. US 1836446 A. April 30, 1928, accessed April 27, 2014 (English, Christie's patent for his drive).
- ^ Robert Jackson: Panzer - Models from all over the world from 1915 to today , Parragon Books, ISBN 978-1-4075-0670-8 , p. 37