TONGS WITH CONTROLLED LOCKING LATCH Russian patent published in 2014 - IPC B25B7/12 B25B7/14 

FIELD: process engineering.

SUBSTANCE: invention relates to hand tool. Hand tongs for, particularly, making of pipe joints in pipeline systems have two arms hinged together by the first hinge joint and are divided into mounting arm and handle arm (2, 3). First handle arm (3) is divided lever (14) remote from said handle and lever (15) arranged nearby said handle. Levers (14, 15) are jointed via second hinge joint by hinge pin (16). Note here that traction wheel (17) and ratchet wheel (18) with external rim (27) are fitted on said pin to spin thereon. Traction wheel (17) engages with traction means (20) coupling two handle levers (2, 3). Spring-loaded pawl (25) fitted on handle lever (15) to engage with ratchet wheel (18) so that both ratchet wheel (18) and traction wheel (17) spin to close the tongs. Spring-loaded latch (30) is engaged with ratchet wheel (18) to allow its rotation at tongs closing and to prohibit it in opposite direction. There is the switch (33) to reverse the direction of spring-loading of locking latch (30) so that in operation of said switch (33) locking latch (30) disengages from ratchet wheel (18). Traction means (20) extends through block and tackle system from traction wheel (17) via guide wheel (21) arranged on second handle arm (2) and, back, to first handle lever (3).

EFFECT: lower force at closing the tongs.

2 cl, 3 dwg