These lines come from the biography of Benjamin Franklin, written in the late 18th century. If you want to understand the last few words, it would help to divide them up like this: [means would be used] [ to prevent me] The first clause - as Behnam corrected pointed out in his comment - is a type 2 conditional in the passive voice. The word 'means' is a noun here, meaning a way or a method. The whole phrase means that someone (presumably Franklin's father) would use certain 'means' to prevent him going openly. We can presume that these 'means' would be a punishment of some kind. Just a side note: This is the second time in the last hour that a member has asked for an explanation of a quotation from a text written several hundred years ago, without giving the source of the quotation. In both cases, a professional native-speaker English teacher replied by saying that the sentence did not make sense. This is an entirely reasonable comment, given how much English has changed over the centuries. Texts that were written in the 17th or 18th centuries do sound strange or even wrong to us, and it's natural ( in the context of a language learners' site) to assume that something that is odd must be non-native error. So ... if you are quoting something from a historical text, please tell us! It will save us all a lot of time and (occasionally) embarrassment.

This is the other "used to" pattern that gets ignored by textbooks. ;) You have "an infinitive of purpose" here, and the meaning is "in order to" or "with the intention to". Read it as, "...(it) would be used in order to prevent me" or "they would use it with the intention of preventing me".

The meaning is literal. means would be used (by my father) to prevent me = my father would use means to prevent me

This is not grammatically correct. The whole paragraph doesn't really make any sense.

it seems that the sentece is conditional two in passive state.