升降貨梯http://www.weheartgrub.com/系統中的換向方式和換向控制參數對換向沖擊有決定性的作用，升降貨梯采用液壓傳動，設計新的液壓換向系統已迫在眉睫。

1、升降貨梯采用行程換向閥的換向方法，換向閥芯上聯出一拔桿，為采用行程換向閥換向，利用工作臺上的行程擋塊推動拔桿來實現自動換向。升降貨梯的工作臺慢速運動時，當換向閥到達中間位置，不管液壓缸左右兩腔或是都通壓力油、或是都通回油、或是都封閉，這時，液壓缸兩腔沒有液壓力推動，都會使工作臺運動停止，因而換向閥不能到達另一端，也就出現了所謂“死點”。
Cargo lifter using the commutation valve stroke, valve core linking the pull rod for the introduction of travel valve for the use of the bench trip block push pull lever for automatic commutation. Cargo lifter bench slow motion, when the valve reaches the intermediate position, regardless of the cylinder about two cavities or through pressure oil, or both through the oil return, or are closed, then, there is no two-chamber hydraulic cylinders hydraulic pressure pushes,will make table movement stops, thus reversing valve can not reach the other end, it appeared the so-called "dead spots."

2、升降貨梯采用電磁換向閥的換向方法，由行程擋塊推動行程開關發出換向信號，行程換向閥改為電磁換向閥的換向方法。使電磁鐵動作推動滑閥換向，可以防止“死點”但它一種開關型液壓閥，根據指令瞬間開啟或閉合，即瞬時接通或切斷回油通道，這樣的液壓換向系統在換向時會有很大的沖擊發生。
Cargo lifter electromagnetic valve commutation method to promote the trip switch issued by the trip block commutation signals, stroke valve solenoid valve instead of commutation. Action to promote the spool so that the electromagnet

commutation, can prevent the "dead spots" but it kind of switching hydraulic valves, and instantly open or closed, the instantaneous switching on or off the oil return passage in accordance with instructions, so that the hydraulic reversing system change will be a great shock to happen when.

3、升降貨梯http://www.weheartgrub.com/采用電液換向閥的換向方法，先導閥沒有換向前，用電液換向閥替換電磁換向閥便構成了一種新的換向方法，電液換向閥由先導閥電磁滑閥和主閥液動滑閥組成。一旦控制油路切換了方向，升降貨梯的主閥閥芯就依照事先調定的速度移動到另一工作位置，主油路方向改變，工作臺也就換向運動，防止了換向“死點”。
Cargo lifter electro-hydraulic valve commutation method, the pilot did not change forward, electro-hydraulic valve solenoid valve replacement would constitute a new commutation method, electro-hydraulic valve by the pilot valve electromagnetic spool valve and the main valve hydraulic slide valve. Once the control circuit to switch the direction of the main valve spool cargo lifter on in accordance with the pre-set speed transfer work to another location, change the direction of the main oil line, the table will change to the campaign to prevent the change to "dead spots . "