求翻译：拧开滑动杆的制动螺丝，向下滑动滑板，当试锥尖端与砂浆表面接触时，拧紧制动螺丝，使尺条测杆下端刚好接触滑动上端，并将指针对准零点。是什么意思？

Unscrew the screws of the sliding rod brake, sliding down the skateboard, when the test cone tip and the mortar surface contact, tighten the brake screw, just contact with the sliding top of the foot bar of the bottom of the measuring rod, and align the pointer to zero.

Turn the slide-bar clamp screws, slide down the chute, taper tip and try mortar surface contact, tighten the screw, bar-bar on slide just touches bottom end, and the needle is aligned with zero points.

正在翻译，请等待...

Slide the rod brake screws unscrewed, slide the sliding plate down, when you try cone tip contact with the surface of the mortar, tighten the clamp screw so that lower foot measuring stick just touch sliding top, and place the pointer at the zero point.

正在翻译，请等待...