| 摘要 |
<p>There is provided a new and useful plug for endwise insertion into a drill hole, the plug including an elongated central body and at least two arrays of ourtwardly extending means being integrally formed with the central body and having outer extremities for engaging the surrounding wall of the drill hole, the juncture of the outwardly extending means of one array being at a longitudinal distance along the central body from the juncture of the outwardly extending means of the other array, the means forming the arrays being flexible inwardly from an unflexed condition wherein the outer extremities of the means in each array are disposed about a longitudinal axis of the plug on a peripheral line of greater diameter than the drill hole, the peripheral lines of the two arrays having a substantial space therebetween in the longitudinal direction of the plug.</p> |
