A rim splitter was used on the outer rims of older vehicles to facilitate removal and replacement of tires. The tool was used to remove a tyre and replace it onto a split wheel rim. After the air was let out, the safety rim key was pulled. The swing arms were spread out and the three arms evenly spaced around the rim. The single arm with the screw gear needed to be close to the split so that the hooks fit on the rim and the rim was then pulled inward and the tyre could be be removed from the rim. After the tire was repaired or a new one was ready to be put on the collapsed rim the tool was used to push the rim back together and the safety key could be reinserted. A rim splitter were a universal type tool used for many cars of the 1920's and 1930's.A cast iron rim splitter which has two hinged side arms with hooked ends. The middle shaft has a hooked end and an inner bolt that can be screwed up or down.St Joseph Michigan Hercules Product Co Made in U.S.A. L 7motoring rim-splitter tyres tool