V+O+to+V to-infinitive

Solution 1:

• I forbade him to enter my building.
• I advised him not to smoke.

These are both B-Equi cases, each referring to two acts: one speech act addressing my opinions in the main clause, with I as speaker (subject) and him as addressee (indirect object); and one other activity to be performed (or not performed, depending) by him, in the infinitive clause. So the idea is that only one copy of him is needed, and it's in the right place to be both the subject of the infinitive and the indirect object of the main verb.

• I want you to be quiet.

This one is clearly B-Raising. You is not an indirect object and has meaning only in the infinitive clause. With want, the infinitive clause (with its subject) is the direct object, and the subject is positioned the same, but doesn't relate to the main verb. Any NP can get raised; consider the funny NP tests:

• I want (for) there to be a party tonight.
• *I ordered there to be a party tonight.
• She wants the shit to hit the fan.
• *She forbade the shit to hit the fan.

• I help her to carry all the boxes.

Help, now, is a rather special verb. It can take either infinitive or gerund complements, and the infinitives allow optional to. Those are signs that a verb has had most of its meaning bleached out and has become a gear in the syntax machine.

Help in this construction is so closely allied to the infinitive that its subject also becomes potentially the subject of the infinitive, possibly in conjunction with its original subject. What does it mean to "help her to carry out the boxes"? Who did the carrying? This is sort of a grey area.

Solution 2:

To-infinitivals are not objects.

For one thing, objects may be passivised, but to-infinitivals, generally, may not.

* To be quiet is wanted you

* To help carry all the boxes was helped her

* To enter my building was forbidden him

* Not to smoke was advised him

Besides this, to-infinitivals are allowed in places where objects, which take the form of noun phrases, are not.

* I want you a doctor

To-infinitivals are also not object complements, a sort of predicative complement which ascribes a property to the object and not the subject of the verb, because they may not be systematically replaced with noun phrases or adjective phrases.

* I advised him healthy

* I advised him non-smoker

It's better by far to consider to-infinitivals a separate sort of complement licensed by certain verbs, and not as objects or object complements as you suggest.