A torsion bar suspension, also known as a torsion spring suspension is a general term for any vehicle suspension that uses a torsion bar as its main weight bearing spring.

On the page 102, picture II.5-55 "Gibajuća pogonska osovina sa torzionim vratilom", there is a working shema of the part named "torzioni štap".
http://www.masfak.ni.ac.rs/uploads/articles/www2_drumska_voz...

On the page 200, picture 282, we can also see "torzioni štap" as a part of torsion spring suspension, placed between wheels.
http://www.motorna-vozila.com/download/Motori i Motorna Vozi...

On the link bellow, we can see the same part as on previous pictures, so we can conclude the following, regardless the vehicle types are different:
"torsion bar spring" = "torziona štap"
http://en.wikipedia.org/wiki/Torsion_bar_suspension

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Note added at 2 hrs (2011-05-10 20:53:39 GMT)
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Here are the pictures of "TORSION BAR SPRING": http://picsus.eu/keyword/torsion bar spring/

http://www.google.com/search?q=torsional bars&ie=utf-8&oe=ut...
http://en.wikipedia.org/wiki/Torsion_bar_suspension
A torsion bar with no load applied.
...
A torsion bar with a load applied.

pq=torsional%20bars&xhr=t&q=torsion+bars&cp=9&qe=dG9yc2lvbmFsYmFycw&qesig=rYhE6jfUJw-EQ5OnxIU86A&pkc=AFgZ2tlu27mWAKTWyt_YTnu1YzUGMARNrehJEb5OwfbkqRForDcjv1Ev9tRR_0dE03JmJyaZA-ZjJ5CVH9CbA56DpPAxc7OKyA&pf=p&sclient=psy&client=firefox-a&hs=PbZ&rls=org.mozilla:sr%3Aofficial&source=hp&aq=0l&aqi=&aql=&oq=torsionalbars&pbx=1&bav=on.2,or.r_gc.r_pw.&fp=9ecd9e91e08e01f&bs=1

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Note added at 8 hrs (2011-05-11 03:00:18 GMT)
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Institut za standardizaciju Bosne i Hercegovine:
http://www.bas.gov.ba/index.php?option=com_sobi2&sobi2Task=s...
Oirginal Title: Railway applications - Suspension components - Torsion bar, steel
Title: Područje primjene na željeznici – Elementi ovješenja - Torzioni štap, čelik

SCIndeks:
Na srpskom:
http://scindeks.nb.rs/article.aspx?artid=1820-02060302067S
Karakteristike elastičnosti torzionih sistema oslanjanja osnovnih tenkova i ocena izvedenih rešenja
...
Ključne reči
tenk; sistem oslanjanja; torzioni štap; elastičnost; potencijalna energija
Isti članak na engleskom:
http://scindeks.nb.rs/article.aspx?artid=1820-02060302067S&l...
Characteristics of torsion bar suspension elasticity in MBTs and the assessment of realized solutions
...
Keywords
main battle tank; suspension; torsion bar; elasticity; work load capacity

Pojam koji se pojavljuje preko 7 200 000 puta na Google-u:
http://www.google.com/search?q="torsion bar"&ie=utf-8&oe=utf...