| 摘要 |
A method is provided for removing an expander from a ground piercing tool of the type having an elongated tubular tool body with a front nose and a striker disposed for reciprocation within an internal chamber of the body to impart impacts to an impact surface for driving the tool forwardly through the ground. The expander is tightly fitted onto the nose of the tool body. The method of the invention uses a pulling device comprising a pair of arms ending in hooks and mounted at ends opposite the hooks to a yoke having a threaded hole therethrough, and a screw including a threaded stem inserted through and threadedly coupled with the hole. Suitable means are provided for engagement with a device for turning the screw. The method according to a first aspect of the invention includes the steps of positioning the hooks of the pulling device in engagement with a pair of rearwardly facing shoulders on the expander, positioning an end of the screw in contact with the nose of the tool, and tightening the screw against the nose of the tool using the turning device on the engaging means, thereby exerting a pulling force through the arms sufficient to disengage the expander from the nose of the tool.
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