Tractel blocstop BS Mode D'emploi page 16

2.1) Operating principle of BLOCSTOP TM
fall arrest device:
GB
Fig. 1
Key:
a: wire rope entry hole
b: wire rope
c: pulling direction
d: unlock stirrup
e: shackle (optional)
f: wire rope exit hole
g: jaws
h: cotter pin
The BLOCSTOP TM type BS fall arrest device (fig. 1) is
basically formed by a system of self-clamping jaws (item g,
fig. 1) mounted in a zinc-plated steel casing.
The unit is connected by its shackle (item e, fig.1) to an
anchor point (item 8, fig. 21) or to the suspended platform
(item 9, fig. 22) with a sling.
So long as the wire rope (item b, fig.1) moves in the fall
arrest device in the pulling direction indicated by the arrow
(item c, fig.1), the jaws automatically open and allow the wire
rope to slide. Conversely, as soon as the wire rope in the fall
arrest device moves in the opposite direction, with respect to
the pulling direction (item c, fig.1), the jaws immediately close
on the wire rope and, as with the TIRFOR ® principle, clamp the
wire rope with a force proportional to the load.
To allow controlled descent of the load, the BLOCSTOP
fall arrest device can be unlocked by pulling on the stirrup
(item d, fig. 1) in the direction of the arrow. This operation can
only be performed provided there is no load on the fall arrest
device. A return spring keeps the stirrup in place against the
fall arrest device (shown by bold dotted line in fig. 1).
The shackle (with its cotter pin) (item e, fig. 1) is mounted
on the fall arrest device optionally.
type BS 2.2) Operating principle of BLOCSTOP
fall arrest device:
Fig. 2
Key:
1: housing
2: lever
3: wire rope guide
4: detection roller
5: fall arrest wire rope
6: lifting wire rope
7: mounting hole
8: rotating pin
A: wire rope entry hole
B: wire rope exit hole
The BLOCSTOP TM type BSA fall arrest device (fig.2) is
formed by a zinc-plated steel housing (item 1, fig. 2) and a
zinc-plated steel lever (item 2, fig. 2) with a zinc-plated steel
detection roller (item 4, fig. 2) mounted at its end. The fall
arrest device is rigidly mounted on the suspended platform by
2 screws + self-locking nuts mounted beforehand in the holes
(item 7, fig. 2). The lever (item 2, fig. 2) is rotated to open and
TM close the jaws.
The fall arrest device operates automatically, and depends
only on the distance f (see fig.2) between the lifting wire rope
(item 6, fig. 2) used to lift the suspended platform and the fall
arrest wire rope (item 5, fig. 2) which runs through the unit
(item 1, fig. 2).
Operation is as follows:
- when the lifting wire rope (item 6, fig. 2) is tensioned, the
lever (item 2, fig. 2) keeps the jaws opened and the fall arrest
wire rope (item 5, fig. 2) slides freely in the unit (fig.7),
- when the lifting wire rope (item 6, fig. 2) is slack, the lever
(item 2, fig. 6), pushed by its return spring in the housing
(item 1, fig. 6) swivels, causing the jaws to clamp on the fall
arrest wire rope (item 5, fig. 2). The suspended platform is
immediately stopped on the side on which the fall arrest
device is installed.
Actuation of the lever (item 2, fig. 2) can be caused by:
a) rupture of the lifting wire rope (fig.8),
b) failure of the lifting hoist,
- 16 -
TM type BSA
User name:
Date
INSPECTION AND MAINTENANCE SHEET
Commissioning date:
OVERHAUL
Technician
Signature
name
- 25 -
Type
of intervention
GB