Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
-- ~174~51
.
This invention concerns a rope sling device for lowering a
pers~n or load on a rope, in which the rope passes around a
fri.ction cylinder firmly attached to a base plate.
Such rope sling devices are known; for example, see US Patent
362,173, 2,691,478, 2,432,741, 848,235, 1,351,734, German
Patent 115,414, German Patent Disclosure 2,739,637,~ Swiss
Patent 39,893. ~ seat belt in which a person to. be lowered
sits, or a load, can.be suspended from the base plate.
Under the weight of the person, the rope sling device then
slides downward on the rope. The braking of the rope sling
device is accomplished by the force of friction which is
formed in the sliding of the rope around the fixed friction
cylinder. In addition to the friction force which is produced
on the fixed friction cylinder, other surfaces are also pro-
vided under some circumstances on which the rope slides and
can therefore .be braked (cf. in US Patent 362,173, the guide
ring (D) and the friction cylinder (E)).
In these known rope sling devices, the speed can be regulated
by the person who is. being lowered on the rope sling device
grasplng the rope and thus slowing it down, or by exerting
another braking force on the rope through a lever. If this is
not the case, i.e.,.if the person to be lowered does not
:
:
,, : , , , ~ : :
1 1 7 1 6 5 1
parti~ipate actively himself in the lowering process in the
sense of increasing the 'braking force, the rope sling device'
moves downward with a speed det'ermined only by the braking
force on the friction cylinder.
However, there'are working situations in which it is desired
that the rope sling device'should stop on the'rope when the
person does not intervene. For example, this is the case in
working situations where a person wishes and should work with
two free hands at a certain height, perhaps on a'facade, while
he himself starts and controls the process of the downward
motion by acting on the braking devices on the rope sling
device. In other words: in the case of complete inaction of
the person to be lowered, the device should stop.
Such a'requirement can also arise in a hazardous situation to
prevent a person moving downward on the rope at an uncontrolled'
high speed, when he can no longer slow the speed of the rope
sling device, for example, because he has become unconscious.
This would lead to injuries upon striking the ground. Those
rope sling devices which, in contrast to the aforementioned
rope sling devices, do not operate with a fixed friction
cylinder but instead with a friction cylinder rotating freely
in the one direction of rotation and locking in the other
direction of rotation, have this drawback (see for example,
US Patent 3,759,346 and 3,807,696).
.,
~ 17~6~ 1
It is therefore :the purpose of this invention to improve
the rope sling device of the type mentioned initially, so
that on the one hand the regulation of the braking speed is
very easily possible, but that on the other hand, in the
absence of any action by the person to be lowered or. by a
helper, an absolutely safe braking is guaranteed until the
rope sling device has come to a.stop. It is also intended
to be guaranteed that there can be no.tangles or sllppage,
and no climbing of coils onto neighboring coils. The rope
must also have the simplest possible ~structure.
This problem is solved pursuant to the invention by providing
that the rope - in addition to. being guided on the fixed
friction cylinder - also passes around a pivoting auxiliary
friction devioe connected to a lever, which is rotated by the
friction of the rope passing around it so that it presses the
rope against another brak;ng surface.
Alternatively, a solution of the problem presented is produced
if the rope, in addition to being guided around the friction
cylinder, also passes around a pivoting auxiliary friction
device connected to a lever, on which a spring exerts a force
so that it pr~ses the rope against another.braking surface.
.
It is therefore common to both solutions of the problem pre-
sented that another auxiliary friction device is provided which
-` ~17~6~1
--4--
presses the rope so strongly against another braking surface
in the normal state that a complete slowing to a stop occurs.
In the first~mentioned solution, this is guaranteed by the
fact that the auxiliary friction device is mounted so that it
is rotated or pivoted Sy the force of friction of the rope
passing around it and thus presses the rope against the braking
surface. An automatic clamping or locking therefore occurs,
which is brought about by the fact that in the downward slide
of the rope sling device on the-rope, the pressure of the
auxiliary friction device against the other braking surface
constantly increases until the motion stops. In the solution
mentioned in the second place, the same effect is produced ky
a spring. In both cases, the person to be lowered (or a
helper) can now grasp a lever with which the auxiliary friction
cylinder is connected, and move it in the opposite direction,
or in the direction against the automatic clamping in the
first solution and in the.direction against the force of the
spring in the second solution. If this is the case, the
frictional force on the rope becomes smaller and the rope
sling device can move downward. In the case of complete
inaction of the person to be lowered, for example, if he wishes
to have both hands free and wishes to work at a certain posi-
tion (when used as a labor device), or in the case of loss
of consciousness or injury ~when used as a rescue device),
however, an increase of the rate of drop is absolutely precluded.
Instead, braking occurs to a full stop. When used as a rescue
'` ~174~51
device, the person must then be rescued in another manner.
Such a rope sling device is quite particularly suitable for
a one-time 'descent on a rope for equipping rooms in the upper
stories of hotels which can no longer' be reached by ordinary
rescue'devices tladders, etc.).
The critical difference from the known rope sling devices
mentioned at the outset consists of the fact that the action
of the auxiliary friction device'is slackened, i.e., reduced
by the action of the person to be lowered.
The first-mentioned of the two solutions, which operates with
the automatic clamping of the auxiliary friction device,'
which is caused by the friction of the rope passing around it,
, i5 preferred when it is important to avoid a spring whose break-
a'ae could be a hazard, for reasons of maximum reIiability
and strong stresses from rough handling. Finally with this
solution, a particularly sensitive speed control is
obtained.
A particularly important beneficial improvement of the inventio~
provides that the base plate with two side plates located on it
forms a chamber accessible from the'front in which are located
the friction cylinder, the auxiliary friction device, and the
: ;
6 ~ ~
-- 6 --
other braking surface, and that a cover is provided by
which this space can be sealed off. In such a form of
the housing, formed by a chamber which can be covered,
the rope on the one hand is guided with complete security,
while on the other hand it can be taken out easily.
Therefore, the rope sling device can be used in repeated
succession, since the rope can be easily taken out and
again replaced in a new starting position. It is not
necessary to put up with any ha~ards at all in the ready
condition, because of this simple resetting capability.
In this design, both the friction cylinder and the
auxiliary friction device can be designed without flanges,
i.e., without special rope guide elements, which leads to
another simplification of handling and of the engineering
construction.
In one aspect of the present invention there is
provided a rope sling device for lowering a person or a
load, the device comprising a continuous length of rope;
a housing having a base plate; a nonrotatable friction
cylinder secured to the base plate, one portion of the
rope being wrapped at least once around the friction
cylinder; a cam secured to the base plate and being
rotatable about an axis eccentric with respect to the
center of the cam, the cam having exterior camming
surface, a stationary braking surface, another portion of
the rope passing between the exterior camming surfaces
and the braking surface, rotation of the cam in a first
direction urging the another portion rope against the
braking surface to tightly capture the another portion of
the rope between the exterior camming surfaces and the
braking surface to prevent further movement of the rope;
and a manually actuated lever for rotating the cam in a
second direction opposite of the first direction to move
the exterior camming surfaces away from the braking
surface to allow further movement of the rope, the lever
having a handle portion to allow manual gripping thereof.
~ ~ 7~ 5 1
-6a-
In a further aspect of the present invention
there is provided a rope sling device for lowering a
person or a load, the device comprising a continuous
length of rope, a housing having a base plate; a
friction cylinder nonrotatably mounted to the base
plate, a portion of the rope passing at least once
around the outer surfaces of the friction cylinder;
a cam secured to the base plate and being rotatable
about an axis eccentric with respect to the center of
the cam, another portion of the rope passing around at
least a portion of the outer camming surface surfaces
of the cam; a stationary braking surface having a curved
configuration and being in spaced, confronting relation
with the outer camming surfaces; a manually actuated lever
extending from the housing and being rotatably mounted
with re~pect to the base plate, the lever having an
exterior handle portion to allow manual gripping thereof;
and gear means coupling the lever to the cam for rotation
of the cam in a first direction when the handle portion
of the lever is manually raised to increase the spacing
between the outer camming surfaces and the braking
surface to allow movement of the rope therebetween,
friction between the outer camming surfaces and the rope
causing the cam to rotate in a second direction opposite
of the first direction to drive the outer camming
surfaces toward the braking surface when the handle portion
of the lever is not being manually raised to capture
another portion of the rope between the camming surfaces
and the braking surface for preventing further movement
f the rope-
In a further aspect of the present inventionthere is provided a rope sling device for lowering a person
or a load, the device comprising a continuous length of
: rope; a housing having a base plate; a friction cylinder
nonrotatably mounted to the base plate, a portion of the
rope passing at least once around the outer surfaces of
~ '
i
,~
,
' , ~
: . :
~ 5
-6b-
the friction cylinder; a generally planar stationary
braking surface facing away from the friction cylinder;
a rod nonrotatably mounted to the base plate adjacent
the braking surface in generally parallel alignment
with the friction cylinder, the rod being spaced from
the friction cylinder, another portion of the rope
passing around the rod to form a loop having an arc of
approximately 180 : a cam mounted to the base plate and
being rotatable about an axis eccentric with respect to
its center, the cam having outer camming surfaces formed
thereon, in spaced, confronting relation with the braking
surface, a third portion of the rope passing between the
braking surface and the outer camming surfaces spring
means for biasing the cam in a first direction of
rotation to move the outer camming surfaces toward the
braking surface to capture the third portion of the rope
between the braking surface and the outer camming surfaces
to prevent further movement of the rope; and a manually
rotatable lever rigidly attached to the cam for manual
rotation of the cam in a second direction opposite of the
first direction to move the outer camming surfaces away
from the braking surface to allow further movement of the
rope, the lever having an exteriorly extending handle
portion for manual gripping of the lever.
Examples of embodiment of the invention are
described in detail below with reference to the attached
drawings. The drawings show:
Fig. l A first embodiment represented with the cover
o~en;
Fig. la An illustration of the use of the embodiment
without action by the person to be lowered;
Fig. 2 A section along the line II-II in Fig. l;
~,.~
" 1 17~6S~
--7--
Fig. 3 A section along the line III-III in Fig. l;
,
Fig. 4 A section along the line IV-IV in Fig. 2;
.
Fig. 5 The example of embodiment pursuant to Fig. 1 with
closed cover, or in the state ready for operation;
.
Fig. 6 A modification of the embodiment of Fig. l;
- Fig. 6a An illustration of the use of the modified embodiment
pursuant to Fig. 6;
Fig. 7 A second example of embodiment, in which a section
of the stationary friction cylinder and of the
~ .
auxiliary friction device are broken away;
Fig. 8 A top view of the embodiment pursuant to Fig. 7,
but without individual components broken away;
Fig. 9 A partial cross section through the embodiment
pursuant to Fig. 7 or 8;
Fig. 10 A section along the line X-X in Fig. 7 or 9;
' .
1 17~65~
--8--
Fig. 11 A third example of embodiment
Fig. 12' A view in the direction of *he arrow XII-XII in
Fig. 11;
Fig. 13 A view in the direction of the arrow XIII-XIII in
Fig. 11; ,
Fig. 14 A section along the line XIV-XIV in Fig. 11.
The rope sling device pursuant to the first example of embodi- .
ment has a base plate 1 on which is located a stationary -
friction cylinder 2. As seen from Fig. 2 and Fig. 3, a
chamber-like housing open towards the front is formed because
~ .1 . .... .
of the fact that ~wo side plates 71 and'72 are firmly connected
to the base plate i. This chamber is closed by a cover 73
with a U-shaped cross section (see Fig: 1 ) which is linked
to the side plate 71 by screws 74 and 75. Fig. 1 shows the
rope sling device with open cover 73. In Fig. 5, the'cover is
closed, and with the use of a helical screw 76 screwed into
the threaded hole 77-tFig. 1) in the side section 72, is fixed
in this closed position. As seen in Fig. 2, the upper cover
section 78 ~which corresp~nds in cross section to the upper
leg of the U in Fig. 1) has a first slot 79. Similarly, the
lower cover section 80 (which corresponds to the bottom leg
of the U in the cross section) has a second slot 81. When the
17~5~ -
g
chamber is closed, or in .the position shown in Fig..5,.the
rope'6 passes through the'two slots. Still ano.ther guide
pin 82 is located on the'base plate 1. 'The rope guide.'block
14 also .ser.ves to secure'the rope 6. when turning ~round the
stationary friction cylinder 2. The. base plate 1 has an
opening 34 in which a person who is to be lowered is sus-
pended by means of a snap hook and eye 35 and a seat belt 36.
The weight of the person then acts on the base plate 1 in
the'direction of the arrow 3.8 in the drawing.
~ An auxiliary friction device 84 is also located on the. base
plate 1 with the help of a bolt 83. The auxiliary friction
device 84 can swivel around the bolt 83, which is screwed
.~ ~ , into the base plate l. 'The bolt 83 fits into an appropriate . ''
hole in the auxiliary friction device 84. This hole is ,
located eccentircally in the auxiliary friction device 84.
As seen from Fig. 4, a ge,ar 85 is firmly joined to the
auxiliary friction device 84. The axis of rotation of this
gear is displaced with respect to the auxiliary friction
device 84, so that upon the rotation of the auxiliary friction
device 84 around the bolt 83, it rotates not eccentrically,
but normally concentrically. The gear B5 is engaged with a
second gear 86 which is connected firmly to the lever 64,'
which is mounted to rotate by the use of a pin 87 in the side
section 72.and which extends outward through an opening 88 in
the side section 72.
.
' '
: `
(
-" 1 17~65 1
--10--
As als~ seen from Fig. 4, the cross section of the upper
region of the side section 72 is designed so that it produces
a curved braking surface 89. As seen from Fig. 1, the rope
6 runs through between the auxiliary friction device 84 and
the braking surface 89.
As also seen from Fig. la, the upper end 6' of the rope 6 is
fixed at any position from which a person decides to
descend. The rope runs from there into the rope sling device
and one and one-half times around the stationary friction
cylinder 2. The rope then passes around the auxiliary fric-
tion device 84 and thus also between the auxiliary friction device
84 and the braking surface 89. From there, it runs downward.
~. ,.. _........................ .
If a person is now lowered with the use of this rope sling
device, the rope 6 slides from below in the direction of the
arrow 39 into the descending rope sling device, and over the
auxiliary friction device 84 and over the friction cylinder 2.
It therefore runs counterclockwise around the auxiliary fric-
tion device 84 with an arc of contact of ca. 180. It then
runs to the friction cylinder 2. It runs one and one-half
times around the friction cylinder 2, and from it again upwards,
out of the rope sling device. The rope 6 is primarily braked .
by the fact that in running around the stationary friction
cylinder 2, a braking occurs because of friction. This
braking force however, is not of such magnitude that with a
o ~ ' l
1-~'7~
person of normal weight, a complete braking results until
the device stops. Instead, a normal speed of .descent
re,sults. because of the braking on the stationary friction '
cylinder 2 alone.
The remaining braking is obtained by the use of'the auxiliary
friction device'84 and the braking surface 89, ,in the follow-
ing way: . ~
(a) The person who is lowering himself with the rope sling
device, does not to~ch the lever 64
The rope runs from bottom to top through the device in the
.... , ~ .
direction of the arrow 39 in the drawing. Because of the
frictional force between the rope 6 and the auxiliary friction
device 84, the auxiliary friction device 84 is rotated
counterclockwise around the. bolt 83. Since this is an
eccentric motion around the bolt 83, the rope 6 is pressed
by the auxiliary friction device 84 against the braking
surface 89. The rope 6 is thus clamped with automatic slowing
and self-retention between the auxiliary friction device 84
and the braking surface'89. If the rope 6 still slides over
the.auxiliary friction device 84 anyhow, it has the tendency
to intensify the force with which the auxiliary friction device
84 presses the rope 6'against the braking surface 89. This
'
' . .
~ ~ 7~5 1
-12-
applies a braking force which constantly leads reliably to
the stopping of the rope sling device on the rope 6.
b) The person who is lowering himself with the rope sling
device presses the lever 64 upward:
The gear 86 then rotates counterclockwise,and the gear 85
rotates clockwise. For this reason, the auxiliary friction
device 84, which is connected firmly to the gear 85, also
rotates clockwise and thus in a dixection in which the distance
between the auxiliary friction device 84 and the braking sur-
face 89 is increased. The automatically intensifying and
self-retaining clamping action between the auxiliary friction
device 84 and the braking surface 89, mentioned above, is
eliminated. The entire braking force is not so strong that
it leads to a complete stoppage. Instead, as previously
describéd, sliding occurs at a speed which depends upon the
size of the radii of the friction cylinder 2 and the auxiliary
friction device 84, as well as on the corresponding arc of
wrap and the weight of the rope sling device plus the person
to be lowered.
Fig. 6 shows a modified form of embodiment. The rope 6 in this
case is guided twice around the stationary friction cylinder 2
and downward out of the rope sling device. The upper cover
' 117~51
-13-
section 78' accordingly no longer has an opening, while an
appropriate larger' opening 81' is prov'ided in the'lower
cover section 80. A bracket 101, which has an opening 102,
i8 welded to the top of the base plate 1.
The method of use of this modified embodiment is illustrated
in Fig. 6a. The 'lowering process occurs through a helper H,
who operates the lever 64 of the rope sling device, which is
designated in Fig. 6a with an A. The rope sling device A is
fastened to a frame 103 with the help of the opening'102.
This frame stands on a surface 104 fixed in location. The
rope sling device is therefore suspended at a fixed point~
The person P to be lowered is suspended with the seat belt
36 at the lower end 6' of the rope 6 running down out of the
rope sling device.
Therefore, this is not the case as in the embodiment pursuant
to Fig. 1, wherein the person to be lowered "moves down on the
rope"; instead, the position of the rope sling device remains
fixed. If the end 6" on which the person to be lowered is
fastened is considered as the forward end, the rope runs from
top to bottom through the rope sling device.
In repeating the lowering process, in the example of embodiment
pursuant to Fig. 1 or Fig. la, the following is true: after
completion of the lowering process, i.e., when the person P
- 1 17~5 ~
-14-
has climbed out of the seat belt 36, the rope 6 with the
rope'sling device suspended from its bottom end is simply
hoisted up again. The cover 73 is then opened, the rope is
taken out, and again placed in so that it is located in the
vicinity of the upper end 6'. Another person can then be
lowered.
In the modified embodiment pursuant to Fig. 6 or the use
pursuant to Fig. 6a, the cover 73 is first opened, the rope
is then taken' out, and the end 6n -is hoisted up. The rope' '
is then placed in again so that the rope sling device'is
then ready for another lowering process.
.
In the example of embodiment pursuant to Fig. 7, the friction
cylinder 2 i5 also fastened to the base plate 1 with bolts 5.
The friction cylinder 2 has flanges 3 and 4. The guide rings
37 and 37' are used as rope guides. A rope guide block 114
is provided above the friction cylinder 2, which surrounds the
coils of the rope 6 on the friction cylinder 2 like a chamber.
When the rope 6 moves towards the rope sling device in the
direction of the arrow 39, it runs past the plate 52 and with
a deflection of ca. 180 around the cylindrical rod 53 welded
to the plate 2. The side of the plate 52 forms the braking
surface 54. The rope 6 runs along this. The braking surface
55, formed from a section of the'outer surface of the cylindrical
~ 1 17~5 1
rod 53, follows this. The rope runs 1-1/2 tLmes around the
friction cylinder ~ and then leaves it through the guide
ring 37. The left side of the plate 52 in Fig. 7 has a
'rounded shape and'covers the space between the two flanges
2 and 3 and thus forms another' chamber-like guide for the
rope.
As is apparent from Fig. 10, a plate 56 is connected at right
angles to plate 52. It forms an integral component with
plate'52 and rod 53 (the plate 56 in Fig. ~ lies in front
of the plane of the illustration and is broken away there).
Between the plate'56 and the base plate 1 is located a rotatable
shaft 57. It constitutes the auxiliary friction device. The
rotatable arrangement is obtained from the journals 58 and 59
of the shaft 57 extendin~ into holes 6~ and 61 in the
plate 56 and the base plate 1, respectively. As seen in
~ig. 7, the cross section of the shaft 57 in the region 62
has an eccentric design, so that an eccentric outer surface
63 results in this region. This outer surface is recessed
into the shaft 57, so that a guide for the rope 6 is formed
at the same time. The shaft 57 is connected to the lever 64,
with which the rotational position of the shaft 57 can be
changed. Depending on the position of the lever 54 or of the ,
shaft 57, the rope in passing between the outer surface 63
of the shaft 57 and the braking surface 54 is pressed with
varying strength against the braking surface 54. In the same
'` 117~51
-16-
way, the friction which occurs in the passage of the rope 6
between the braking surface 54 and the rope 6 and also
between the outer surface 63'and the rope 6 is of varying
strength. On the other hand, in the position 64l drawn in
Fig. 1 with broken lines, there 'is no braking. The rope'
6 then passes freely through.
The shaft 57 is provided with an annular groove on~the'right
side in Fig. 4. A torsion spring is loGated in this, one'
end of which extends into an opening in the base plate 1, and
the other end into an opening in the shaft 57, and is pre-
stressed so that it presses the lever 64 in the direction of
the arrow 28. Thé effect described above is thereby produced,
namely the outer surface 63 of the shaft 57 is pres'sed against
the rope 6, if the lever 64 is not pushed upward by the person
to be lowered.
In the third example of embodiment, the friction cylinder 2 is
a'lso located firmly on the base plate 1. The rope is also
wound with 1-1/2 windings around the frictional cylinder 2,
It runs on the friction cylinder 2 over the bottom crossbar
of an oval guide bar 7, which is connected with a brace 9
which is bolted fast to the base plate 1. The oval guide bar
(cf. Fig. 2) is formed by the 'two longitudinal bars 10 and 11,
the'lower crossbar 8, and the upper crossbar 12. The bars 8,
. . .
.....
1 17~65 ~
10, 11, and 12 define a guide opening 13 through which the
rope 6 passes. '
The lever 18 is linked with capability of pivoting to the
top of the rope'guide block 14. It consists of a flat steel
bar 19 and a pipe sectiQn 20 welded to it. A pulley 21 is
welded fast to the upper end of the'flat iron bar 19 (cf.
Fig. 5). A hole 22' extends through the upper end-of the
flat iron bar 19 and the pulley 21, through which 'is passed
a bolt 22 which is bolted fast to the rope guide block 14.
The bolt connection is secured by another bolt 23 which acts
on a smoothly turned cylindrical section 24 of,the bolt 23.
The lever 18 can therefore pivot around the bolt 22.
The auxiliary friction device 25 is firmly attached to the'
brake handle 18 (cf. Fig. 12). Its location on the brake
handle'18 (cf. Fig. 1) is such that the rope 6, before it is
diverted by ca. 180 at the lower crossbar 8 of the guide
frame 7, passes through between the friction cylinder 2 and
the auxiliary friction device 25. It is thereby pressed by
the braking surface 25' of the auxiliary friction device 25
against the surface of the windings of the rope 6, which
lie on the frictio,n cylinder 2. This surface area of the
windings forms the other' braking surface 25"'. The auxiliary
friction device 25 is provided with a flange 26 which pre-
vents the rope 6 from sliding laterally off in case of
.
~ 17as65 1
-18-
careless handling,
A tension spring 27 is provided between the friction cylinder
2 and the lever 18, which pulls the lever 18 in ~he direction
of the arrow 28. Its other end is fastened to the friction
cylinder 2 by the use of the swivel plate 30 and the bolt 29;
at its other end, it is fastened to the lever 18 by the use
of the swivel plate 31 and the bolt 32.
A rod 33 is welded to the upper end of the oval guide frame 7,
which represents a stop for.the lever 18 in the direction
opposite to the'arrow 28.
A guide ring 37 is attached to the 'top of the base plate 1
to secure the,rope 6.
~The rope 6 covers'the fo~lowing path in the lowering of the
rope sling device (cf. Fig. 1). It runs from below up to
the rope sling device (arrow 39 in Fig. 1). It then runs
between the braking surface 25" (the coils of the rope 6
around the friction cylinder 2) and the braking surface 25'
on the auxiliary friction device 25. It then runs to the
crossbar 8 of the guide frame 7 and is diverted by it by
ca. 180. The section of the surface of the crossbar 8 over
which the rope 6 runs is designated by 8' and also acts as a
. - ' . '
- 117~;i51
-19-
braking surface. After the 180 diversion, the rope 6 runs
up to the stationary friction cylinder 2 and passes around
it 1-1/2 times or 2-1/2 times. It then runs upward through
the guide ring 37.
The rope is slowed by frictional force (a) on the surface of
the frictional cylinder 2, (b) on the braking surface 8' of
the crossbar 8, (c) on the braking surface 25' of the auxiliary
friction device 25' of the auxiliary friction device 25, and
at the braking surface 25".
.
The braking force pursuant to (c) can be varied by the person
sitting in the seat belt 36 pushing the lever 18 opposite to
the direction of the arrow 28. On the other hand, i the
person to be lowered leaves the lever 18 completely alone,
the force exerted by the braking surface 25' on the rope 6 is
determined only by the f,orce of the tension spring 27. This
is chosen to be at least so strong that when the brake handle
18 is left alone, the rate of fall is so slow that there is
no risk to the person. It can also be so strongly adjusted
that the person comes completely to a standstill.
