Rubber crawler belts to be used in a light-weight robot, etc. have been developed. The crawler belts have tread lugs on outer periphery thereof and equally-spaced projections for engaging with a wheel or a sprocket on inner periphery thereof. Such crawler belts, however, tend to stretch too much, go slack and come off the wheel after long use. Sometimes they may break due to lack of strength. If the crawler belts are increased in thickness to overcome these shortcomings, they are increased in weight, too.
To address the above-mentioned problem, technologies have been developed to reinforce the crawler belts by embedding an endless high-tensile-strength belt made of thin metal belt, etc. in a rubber-made main body of the crawler belt as disclosed in the patent documents 1 to 3 listed below.
Patent Document 1: Japanese Patent Application Laid-Open No. H6-156333
Patent Document 2: Japanese Patent Application Laid-Open No. H6-199253
Patent Document 3: Japanese Patent Application Laid-Open No. H6-329057