Importance

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Abstract

There is a need for a device for driving plastic casing into a water well, or for removing such casing from the well without damaging the casing. This need is met by a casing drive apparatus which includes a shoe for attachment to the bottom end of a plastic well casing, an annular groove defining a pair of shoulders in the sleeve, a drive sub for insertion into the sleeve, a plurality of dogs pivotally mounted in the drive sub for engaging the shoulders, and helical springs for biasing the dogs outwardly into engagement with the shoulders, whereby, when the sub is slid into the sleeve and the dogs engage the shoulders, vertical force exerted on the sub results in movement of the dogs against the shoulders to effect vertical movement of the sleeve and consequently of the well casing.

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First Claim