that permits lifting without any stress..... - 翻譯

請問以下句子

Lifting of the brushes base group with manual control, hydraulic, patented,
that permits the lifting without any stress maintaining always the same
predefined pressure (up to 80 kg). The lowering is controlled with a lever on
the instrument board that acts with the proper speed and without blows.


我翻成:
以專利的手動控制液壓系統舉起刷子基本組,不需維持在相同的預定壓力(最大到80KG),
而以在儀表板上的調整桿以適當的速度降下刷子.

但關於that permits the lifting without any stress maintaining always the same
predefined pressure (up to 80 kg).這句話

我以為是"不必"維持在一定的壓力下,
但問過幾個人,
它們說是:要維持在一定的相同壓力下，但不一定在80公斤, 80kg是它的上限


請問到底是要維持還是不要?
我以為that permits the lifting without any stress (which is) maintaining
the same predefined pressure. 中間是否省略個關代如上

求解如上多謝進來看看的人




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