Hey translators! I'm working on the translation of a manual from english to spanish, and I was wondering if anyone could help me translate "stop block" in the following context:

"The installation of mid-disk: the side with more apertures should be face down ,and the metal
handle should be placed between two stop block. As shown in figure 8-55."

The manual was (unfortunately) translated from chinese into english, and since it is so technical im not quite sure what they mean by it...

imagino que es alguna especie de prensa?