Carl Stahl Kromer 7251, Manual

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●
It is strictly forbidden to operate the zero gravity balancer
without the safety components supplied (safety chain,
spring fracture safeguard, etc.).
●
A safety chain strained by a falling balancer must be
replaced at once, together with the balancer’s housing.
Installation
Prior to installing the zero gravity balancer, verify that the
suspension structure to which the balancer and its safety
chain are fastened provide adequate stability. The balancer
type 7251 features a rotatable and swivelling safety hook
(2), whereas the balancer type 7261 has a swivelling
suspension eye.
To install the zero gravity balancer, be sure to proceed as
follows:
●
Via the safety suspension (2), suspend the balancer so
that it can be easily aligned and moved in any working
direction (DIN 15112, Part 3.2).
●
It is mandatory to mount the supplied safety chain (4) in
addition to the safety suspension (2) in accordance with
the provisions of DIN 15112, Part 3.2. Note that the maxi-
mum falling distance permitted is 100 mm! It must be
guaranteed that the anti-crash safety device does not
interfere with the balancer across its entire working ran-
ge.
●
Attach the load to the screw-type spring hook installed at
the cable end, then close the hook and screw the knurled
lock nut in place.
●
Adjust the balancer to the working load (see description
under Adjusting the working load).
●
If the zero-gravity balancer is operated with welding
tongs, an insulated suspension is required for the balan-
cer due to the leakage currents involved (see VDE 0100,
section 19, and VDE 0545).
Adjusting the cable length
The zero gravity balancer comes with a long cable so the
cable length can be individually adjusted to on-site require-
ments. Adjusting the cable length is done with the cable
wedge (7). After lengthening or shortening the cable as
required, the free cable end must be compressed with the
supplied ferrule (8) (or with a clamp complying with DIN
3093, Parts 1 to 3); the projecting cable end must then be
cut off flush.
A minimum distance of 100 mm (or 200 mm for type
7261) must be maintained between the cable clamp
and the cable wedge.
Adjusting the suspension
Fine adjustment of the suspension is possible to ensure
low-wear cable and drum operation. To this end, adjust the
suspension hook along the bolt so that the zero gravity
balancer is suspended in a more or less horizontal position
within the working area.
The hook distance to be maintained on the left above the
housing slot should be as follows for the various load ran-
ges, relative to the specified maximum load (factory setting):
7251-01 = approx. 8 mm 7251-09 = approx. 1 mm
7251-02 = approx. 9 mm 7251-10 = approx. 1 mm
7251-03 = approx. 10 mm 7251-11 = approx. 1 mm
7251-04 = approx. 11 mm
7251-05 = approx. 12 mm
7251-23 = approx. 8 mm
7251-06 = approx. 13 mm 7251-24 = approx. 9 mm
7251-07 = approx. 14 mm 7251-25 = approx. 10 mm
7251-08 = approx. 1 mm 7251-26 = approx. 11 mm
7261-01 = approx. 15 mm 7261-04 = approx. 15 mm
7261-02 = approx. 15 mm 7261-05 = approx. 15 mm
7261-03 = approx. 15 mm 7261-06 = approx. 15 mm
Proceed as follows: Loosen the suspension’s clamping
screw (3), move the suspension appropriately, then retigh-
ten the clamping screw (3).
Adjusting the working load
The zero gravity balancer has been factory-preset to the
maximum load permissible for the type/model in question.
●
After attaching the load, apply a size-19 socket span-
ner/wrench to the endless screw (9), then rotate the
spanner in the direction of the “-” symbol until the weight
of the suspended working load is exactly counterbalan-
ced.
●
When setting the minimum load, never extend the cable
beyond a length of 1.5 m (7251) or 0.75 m (7261) respec-
tively, as otherwise the spring fracture safeguard may be
tripped. In case the safeguard mechanism has already
been activated, first carefully preload the spring in the “+”
direction as far as it will go (the spring is now fully “on
block”), then adjust the tension again to the working load
by rotating the endless screw (9) in the “-” direction.
●
To prevent spring destruction, do not slacken it too
much! Full spring release is permitted only if no load
is connected!
●
Infinitely variable load adjustment is possible within the
balancer’s load range (see rating plate (1) for details). To
adjust to lighter working loads, simply rotate the endless
screw (9) in the “-” direction; for heavier loads, rotate it in
the “+” direction. Note that the zero gravity balancer may
not be operated outside the working range indicated on
the rating plate!
The balancers type 7251 0000 23...26 feature a manual
drum lock that allows blocking the cable retraction at a pre-
determined point. To adjust this stop, pull the chain down-
wards to remove the pin from the locking bolt. To set the
cable drum into operation again, pull the chain again and
reinsert the pin into the bolt.
The manual drum lock should never be used for load
replacement!
Cable stop buffer/
Adjusting the cable extension
The cable stop buffer can be easily adjusted by loosening
the screws and simply moving the elastic ball or stop buffer
(5) and the cable clamp (6) to the desired position within the
cable extension section. Be sure to tighten the cable clamp
screws properly after each adjustment.
Never exceed the maximum permissible cable extension
(whether or not the cable length has been increased)!
The limit or end stop is marked by the factory-installed
ferrule.
Drum lock
The drum lock (10) allows you to block the drum for cable
replacement, without any need to unload the spring (see
description under Replacing the cable).
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