| 摘要 |
A self propelled burrowing device 1 for forming a passageway through a material. The device 1 comprises a plurality of propulsion means 4 which are selectively driven by drive means, in response to gravity, in order to maintain a vertical direction of movement of the device 1. The propulsion means may comprise continuous tracks. The device may be used to provide an air passage 24 through snow between an avalanche victim 20 and the surface. The device may contain means for transmitting an audio, visual or radio signal. |
