Harrington Hoists and Cranes RHN - Rhino Wire Rope Hoist - Manual (Page 32)

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3) The upper geared limit switch S3 ↑ should activate before the BLS↑ limit switch. If this is
not the case, reset the S3 ↑ limit switch according to Section 3.8.7
4) Observe that the distance between the top of the hook block and the next obstacle is greater
than 3.5”. This distance is the minimum clearance dimension (2”) plus the minimum
distance between S3
↑ and BLS↑ (¾”) plus the minimum distance between BLS↑ and S1↑
(¾”), see Figure 3-17 . If the clearance dimension is less than 3.5”, reset the upper limit
switch, see Section 3.8.7 .
5) Activate the “down” button on the control pendant carefully, observing the hoisting motion,
until the S2 ↑ lower geared limit switch disables hook motion in the down direction.
6) Observe minimum clearance between rope guide (S) and the rope anchor clamps (K). There
clearance between the should be equal to or greater than 3/4” (20mm), see
Figure 3-17 . If
necessary, reset the lower limit switch, see Section 3.8.7
3.8.4 Testing the high to low and low to high speed transition limit switch, S4 ↑↑ and S4↓ ↓ .
1) Activate the “up” button on the control pendant. Carefully observing the hoisting motion.
2) Ensure that the S4 ↑↑ (low speed transition limit), activates at least 2.0 in. (50mm)
before the upper limit, S3 ↑ , see Figure 3-17 . This means that the hook motion should
transition from high to low speed at least 2.0 in. (50mm) before the hook motion
completely stops at S3
↑ .
3) Lower the hook block from S3 ↑ and ensure that the hook motion is at low speed until
S4 ↓ ↓ . Once switch S4↓ ↓ is no longer activated, the hoist will have the ability to run at
high speed in the down direction see Figure 3-18.
4) Reset the limit switch if necessary, see Section 3.8.7 .
3.8.5 Testing the S1 ↑ (Safety Limit Switch)
The safety limit switch, S1 ↑ , is tested at the factory and does not require on site testing. If
replacing the geared limit switch, consult the factory for proper adjustment.
3.8.6 Testing the BLS ↑ (Block Operated Limit Switch).

The hoist is being operated while testing the BLS. Keep away from all
moving parts to ensure your safety and the safety of others.
3.8.6.1 Lower the hook 2-3 feet below the S3 ↑ switching position.
3.8.6.2 Begin raising the hook at slow speed and manually lift the ball weight of the BLS
that is located above the hook block. Lifting the weight removes the tension from the rope
that is holding the switch closed. The hoist should be inoperable in the up direction as long
as the switch remains open, but should be operable in the down direction.
3.8.6.3 Adjust the limit switch if necessary, see Section 3.8.7
3.8.7 Setting hoist limit switch ( Figure 3-17 , Figure 3-18, Figure 3-19, Figure 3-20, and Figure 3-21 ).
1)

The cover of the limit switch must be removed to set the contacts. This
exposes live contact connections. There is a danger of contact with electrically live parts!
2)

The limit switch is state of the art construction and is safe in
operation. However dangers may arise if it is used incorrectly and not for its intended
purpose.
3) The limit switch can be adjusted at the setscrews (S1), (S2), (S3), and (S4) see Figure 3-21.
 Turning to the left: switching point is moved “downwards”.