| 摘要 |
<p>A power driven pipe threading machine is provided with a coolant system by which an oil free, glycol based coolant is dispensed onto the workpiece during thread cutting in the area thereof adjacent a thread cutting die at a rate which provides for the coolant to completely evaporate and for the workpiece to be cooled to a temperature which provides a good quality thread. The coolant is pumped from a reservoir to a coolant outlet on the die head of the machine and through a needle valve by which the discharge rate is adjustable, and a torque responsive shut-off valve is associated with the die head for controlling the flow of coolant from the reservoir to the needle valve and coolant outlet in response to initial threading engagement between the workpiece and cutting dies on the die head.</p> |
