| 摘要 |
According to one or more aspects of the present disclosure, an engaging member for operating a subsurface valve between an open position and a closed position includes a bottom portion comprising a terminal end adapted for contacting a valve closure member, the bottom portion having a first material characteristic and an upper portion having a second material characteristic that is quantitatively different from the first material characteristic. The material characteristics include, without limitation, strength, coefficient of friction, and the modulus of elasticity. |
