Türkçesini bulamadım, aşağıdaki referanslarda anlatılanlara göre işaret çubuğu denebilir diye düşündüm.

“..a 0.5 m long tailpipe with several 10-12 mm wide vertical slots is a common design, and a horizontal cylinder (≈ 6 mm) of metal, the “tag bar”, is welded across the bottom of the tailpipe to serve as a firm location that can be tagged when lowering the rotor, and also to catch the rotor if rod twist-off should occur, hence saving a fishing trip.”
“… by carefully lowering the rod string until the stator bottom touches the “tag bar” in the bottom of the tailpipe...”
http://www.energy.gov.ab.ca/OilSands/pdfs/RPT_Chops_chptr6.p...

“Tag bar 188 can be a nipple or other structure connected to the lower end of stator housing 186…. “
“Tag bar 188 can prevent the end of rotor 190 from descending too far past stator 182 when rotor 190 is lowered into position…”
“After stator 233 is installed, rotor 278 is inserted on drive rod 280 through stator 233 of PCP 266 until rotor 278 contacts tag bar 284. Rotor 278 may then be pulled back a predetermined distance such that there is clearance between rotor 278 and tag bar 284…”

http://www.faqs.org/patents/app/20110284238

“Tag bar: connected straight below the stator, the tab bar is the reference point for the space-out operations. It also holds the rod string and prevents it from falling to the well bore during the unfortunate event of rod failure.”
http://www.ovtekp.com/_d270295335.htm

resim:
http://www.europump.ca/uploads/euromax.pdf
http://www.europump.ca/uploads/europump_products.pdf
http://www.santos.com/library/NSW_CSG_REF_Longlea_1_Pump_Tes...