At this point the next scoop would descend onto the checking fork, and the left upper lock would reengage, checking the rotation of the drive wheel. The right upper lock prevented the wheel from recoiling and turning backwards.
這時候，下一個受水壺降落到格叉上，同時天關已下降，即左天鎖關上，卡住樞輪，使樞輪不再往前轉，並利用右天鎖來防止樞輪因反作用力而倒轉。