| 摘要 |
<p>Disclosed herein for use with earth penetrating tools is an improved lubricant pressure relief system that utilizes a housing adapted for retention within a lubricant containing passage. An interior surface or opening of the housing is exposed to the lubricant in the passage and includes an outlet port which has an elastic pressure responsive valve covering the opening. The valve releases lubricant when a selected pressure is exceeded while excluding the entrance of exterior matter. The valve functions as a secondary pressure relief valve when used in combination with a spring biased pressure relief valve located within the opening of the housing, which is thereby protected from exterior matter and its successful operation assured.</p> |
