Ciao non è il mio settore, ma secondo la tua definizione, equalizer o
equalizing bar è il termine esatto.
Ti riporto la definizione dal dizionario di scienza e tecnica Zanichelli McGraw-Hill:

bilanciere=
equalizer:
[ING MECC]
1 bilanciere
A bar to which one attaches a vehicle's whiffletrees to make the pull of draft animals equal. Also known as equalizing bar.
2 bilanciere
A bar which joins a pair of axle springs on a railway locomotive or car for equalization of weight. Also known as equalizing bar.
3 bilanciere
A device which distributes braking force among independent brakes of an automotive vehicle. Also known as equalizer brake.
4 depezzatrice
A machine which saws wooden stock to equal lengths.

Balancer è invece il bilanciatore:
balancer
[ELETTR] bilanciatore
A mechanism for equalizing the loads on the outer lines of a three-wire system for electric power distribution, consisting of two similar shunt or compound machines which are coupled together with the armatures connected in series across the outer lines.

Queste invece sono le definizioni di rod:
rod
[ING NUCL] barra
A relatively long and slender body of material used in, or in conjunction with, a nuclear reactor; may contain fuel, absorber, or fertile material or other material in which activation or transmutation is desired.
[MECC] - V. perch.
[PROG MECC]
1 asta di perforazione
A bar whose end is slotted, tapered, or screwed for the attachment of a drill bit.
2 ferro tondo; asta di legno tonda
A thin, round bar of metal or wood.

e di beam:
beam
[ARCH NAV] larghezza; larghezza massima
The width of a ship at its widest point.
[FIS] fascio
A concentrated, nearly unidirectional flow of particles, or a like propagation of electromagnetic or acoustic waves.
[ING CIV] trave
A body, with one dimension large compared with the other dimensions, whose function is to carry lateral loads (perpendicular to the large dimension) and bending movements.
[TESS] subbio
Spool-shaped holder, 8 to 12 feet (2.4 to 3.7 meters) in length, on which is wrapped yarn that is to be transferred to the warp holder of a loom.

Spero di averti chiarito le idee.
Buon lavoro
Paola

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Note added at 6 hrs (2006-05-10 15:41:05 GMT)
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rocker arm è invece il bilanciere in questo senso:

rocker arm
[ING MECC] bilanciere
In an internal combustion engine, a lever that is pivoted near its center and operated by a pushrod at one end to raise and depress the valve stem at the other end.