URB 2,5A Drill rig gin is equipped with two trommels placed on one shaft. One
trommel is meant for tool support during drilling, the other trammel is for
round-trip operations, shaft ends rest upon spherical bearings 4 (Drawing 6).
Drawing 6. Gin
1 – gin shaft; 2 – gin trommel; 3 – wedge key; 4 – spherical bearing; 5 – chain wheel; 6 - sleeve; 7 - chisel; 8 – ball bearing; 9 – spline key; 10 – sliding key; 11 – index pin; 12 - nut; 13 - strap; 14 – pressure lever; 15 - axe; 16 – ring nut; 17 – retaining ring; 19 - disc; 20 – center disc; 21 - backplate; 22 - spring; 23 – grease cup
Trommels are mounted on ball bearings 8, that are seated on the shaft (landing fit) and separated with sleeves 6.
Trommel is provided with a hole to fix cable with a chisel 7.
Trommels have friction couplings providing trommels independent actuation.
Back plate 21 is mounted on shaft 1 spline key 9 and fixed with round nut 12.
Every gin friction clutch consists of three inserted in the ring gear center discs 19, between which there are two intermediate discs 20 set on the back plate gear rim.
The discs are pressed by front plate 18, which is set on the back plate gear rim too.
Retaining ring 17 is inserted in the front disc, shoulders 14 of pressure lever thrust retaining ring inner collar. Lever shoulders swing on axes 15, nested in the back plate hub reaming lug. Collet is mounted on the shaft by sliding key 10 inserted in the slot and fixed with screws. To move collet along the shaft strap 13 with bearing is put on it.
With clutch engagement collet moves inside the coupling, pressure lever rollers move on to the conical part of the sleeve, pressure levers turn round their axes and press the discs with shoulders thrusting retaining ring lug. When friction clutch is disengaged discs are easier to decouple in virtue of three specific sleeves with nested springs 22.
Springs move outer plate from the back plate making possible fast and accurate clutch disengagement. Torque data from the friction clutch is controlled by ring nut 16 with fixing device, index pin 11. To prevent retaining ring 17 rotation guide pins are screwed in the retaining ring with their ends placed in the front plate body holes.
Chain wheel 5 with number of teeth z = 70 for double-strand bush roller chain with chain pitch t=25,4 mm is seated on wedge key 3 for gin shaft drive 1 from the transmission.
Every gin trommel is fitted up with the drum brake with independent control transferred to brake lever.
Levers are connected with axes by pull rods transferring motion to clutches and with the help of them brake band tension is adjusted.
Free brake bands should assume easy gin trommels rotation by hand and fixed brake bands should guarantee gin trommels secure stop.
Gin trommels are provided with grease cups 23 for bearing chambers oil charging during gin assembling and operating service or repair.