摘要 |
A superior ram-boring machine“mole”, employing compressed air to drive a reciprocating piston onto either forward or rearward anvils thereby imparting momentum. Wherein a control valve received into the rear of the piston interacts with ports therein determining its stroke characteristics. The end receiving impacts, and hence the direction of action are determined by accurately positioning the control valve forwardly or rearwards. Incorporating a robust, air-on, fail-safe“Rapid Reverse”mechanism, actuated by a small rotation of the air hose. Whereby guide means and an indexing collar incorporating or comprising encompassing spring or elastic means having inter-engaging features deforms by flexing and or compression to disengage and is biased to re-engage with corresponding features to position and lock the control valve into forward and reverse settings; thereby assisting easy switching, location and retention of operating positions. The invention also provides improvements in durability, product life, ease of operation and servicing. |