Note: Descriptions are shown in the official language in which they were submitted.
CA 02731080 2011-01-17
Description
ELECTRONICALLY CONTROLLED CATCHING DEVICE FOR A FALL
PROTECTION SYSTEM
Technical Field
[0001] The invention relates to a fall arrester for a fixed climbing
protection
system for preventing a person from falling off a ladder, a platform or the
like. The fall arrester, which is also called a runner, is guided in a guide
rail. The person to be secured wears a full body harness and is connected
to the runner via a connection means. For this, the connection means is
fastened to an anchor point of the runner. The fall arrester has a locking
device which can be shifted between a first, unlocked position and a
second position locking the fall arrester on the guide rail. A holding device
holds the locking device back in the first, unlocked position, and the
locking device is preloaded into the second, locking position. In the event
of a fall, the locking device is triggered in speed-dependent manner.
State of the art
[0002] Mechanical fall arresters are known from DE-U-295 01 716 and WO
99/49939. The fall arresters are guided along the guide rail of the climbing
protection system. The locking device has a swivellably housed catch,
wherein one end of the catch has the anchor point and the other end a
detent lug and wherein in the case of a fall the detent lug engages in
catching stops of the guide rail and thus prevents a fall. The catch is
preloaded into the locking position via a spring. The detent lug of the catch
points downwards, with the result that during ascent the catching stops of
the guide rail are travelled over. During descent, the user leans back
slightly (leaning back), with the result that the catch is brought into the
unlocked position and the runner can move downwards unhindered.
[0003] As a fall in a climbing protection system is different above all
because of
the increased speed of the entrained runner compared with the normal
speed of travel within the climbing protection system, it is conceivable to
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design fall arresters with speed-dependent locking devices. Such a fall
arrester is described in DE 103 42 627 Al. The fall arrester described
there has a spring-loaded catch, on the non-catching end of which there is
a feeler roller, and an anchor point. If the person to be secured moves
slowly and in a controlled manner down the climbing protection system,
the feeler roller is guided over catching stops of the guide rail, wherein a
spring always pulls the catch back into its starting position in good time,
with the result that the catch does not engage in the catching stops of the
guide rail. In contrast, in the case of a fall, during which the fall arrester
moves clearly faster along the guide rail, there is not enough time for the
restoring spring to pull the catch back into the starting position, with the
result that the catching end engages in the catching stops of the guide rail
and thus prevents the fall. However, a disadvantage of this fall arrester is
that the mechanical parameters that determine the catching speed, such
as the spaces between the catching stops or the moment of inertia of the
catch, can no longer be varied after completion. It is thus not possible to
adapt the properties of the fall arrester to the conditions in question.
[0004] A fall arrester with a speed-dependent locking device is also known
from
EP 1 820 539, wherein the locking device has a centrifugal clutch. During
movement of the fall arrester, a friction wheel rolls along the guide rail and
its circumferential velocity is thus proportional to the speed of the fall
arrester. When a defined speed threshold value is exceeded, a restraint
device is released by the centrifugal clutch, with the result that a preloaded
locking bar is pressed into a recess in the guide rail and the fall arrester
is
thus locked.
[0005] An emergency braking system for an elevator is known from DE 21 28
662, in which a generator ascertains an electrical value that corresponds
to the speed of the elevator. When a threshold value is exceeded, the
locking device is triggered via an electromagnet and the movement of the
elevator is stopped. The locking device itself consists of two pairs of brake
shoes, the toothed outer edges of which can engage with opposite guide
rails of the elevator and bring the elevator to a stop via friction.
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Description of the invention
Technical problem
[0006] The problem of the present invention is to provide a fall arrester, the
locking device of which reacts to speed, wherein the speed at which the
locking device engages can be adjusted.
Technical solution
[0007] According to the invention, this problem is solved in that the fall
arrester
has an electronic apparatus for determining speed which triggers the
locking device depending on the speed of the runner.
Advantageous effects
[0008] The locking device is triggered particularly quickly as a result of the
electronic speed determination.
[0009] The locking device preferably has a holding device with an
electromagnet,
wherein the holding device is uncoupled or released by exciting the
electromagnet.
[0010] The fall arrester preferably has an electronic control system which
activates the locking device by uncoupling or releasing the holding device
if the speed of the runner exceeds a predetermined threshold speed, e.g.
in the event of a fall.
[0011] The locking device preferably has a mobile stopping element which is
held, during operation, in a first, unlocked position by means of the holding
device. If the holding device is uncoupled, the mobile stopping element is
disconnected and pressed into the second, locking position by a stressing
element, e.g. a spring.
[0012] The mobile stopping element is preferably a mobile bolt or a rotatably
housed catch.
[0013] The locking device preferably represents a combination of electrical
and
mechanical protection means. For this, the locking device has a two-part
catch. One part of the catch is formed by the detent lug rotatably housed
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on an axis. The other part is formed by a mechanical lever which is also
rotatably housed, expediently on the same axis as the detent lug, and
which has the anchor point. The lever and the detent lug are held together
by means of the holding device, with the result that the combination of
lever and detent lug functions like a conventional catch. If the holding
device is uncoupled, the detent lug detaches itself from the mechanical
lever and is pressed into the locking position. The two-part design of the
catch also makes it possible to reduce the reaction time of the locking
device.
[0014] Moreover, the two-part embodiment has a particularly positive effect
should the electronic control system of the electromagnet malfunction (e.g.
defective electromagnet). As a result of the advantageous combination of
mechanical and electronic protection means, the fall arrester is then in fact
not without effect, but can still provide adequate protection for the user
with the help of the mechanical locking device. As a result of this
embodiment, the proven safety of conventional fall arresters is
supplemented in a particularly advantageous way by the option of
individually setting the speed at which the locking device is triggered and
adapting it to the special needs of the user as well as the conditions of the
respective climbing protection system. The fall arrester thus increases the
safety of the climbing protection system and, at the same time, offers a
substantially greater ease of use than with conventional fall arresters.
[0015] In the two-part embodiment, by the first unlocked position is meant
here
the position in which the detent lug is held against the lever by the holding
device. In the second, locking position, in contrast, the holding device has
released the detent lug, with the result that the latter has detached itself
from the lever. If the electronic system fails and therefore the mechanical
lever swivels together with the detent lug, like a conventional, one-part
catch, against the catching stops of the guide rail and locks on them, the
detent lug is in the locking position, although the holding device has not
released and still holds back the detent lug. However, electronic systems
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normally react more quickly than mechanical systems, with the result that,
for the sake of simplicity, this linguistic inaccuracy can be accommodated.
[0016] For determining speed, the electronic apparatus preferably has a
generator which is driven via a wheel or a roller, wherein the wheel is
pressed against the guide rail of the climbing protection system, with the
result that it is in constant contact with the running surface of the guide
rail.
[0017] The electrical energy that is generated by the generator when the
runner
moves on the rail is preferably also used to supply electrical energy to the
electronic control system and the electromagnet. In particular, the
electrical energy generated by the generator can be stored in capacitors in
order to provide the control system with enough energy to excite the
electromagnet. The electrical energy provided by the generator can alone
be enough to supply the control system and the electromagnet. The fall
arrester is thereby completely self-sufficient and independent in relation to
the energy supply.
[0018] The electronic apparatus for determining speed can also have other
optical or electronic elements. In a preferred embodiment, the speed of the
runner is determined via an optical sensor (e.g. speckle sensor) using the
optical flow. The speed can also be determined via capacitive or inductive
methods.
[0019] The speed threshold is preferably chosen such that it is above the
speed
that the runner reaches when the user is using the climbing device
normally. The fact that the locking device of the runner is triggered
depending on its speed makes the blocking of the runner independent of
possible stresses on the anchor point by the user. In the case of a fall, the
blocking of the runner is not prevented by the fact that the user pulls on
the anchor point.
[0020] In the event of a fall, the locking device according to the invention
can
react earlier than according to the state of the art. In particular, the
threshold value of the speed is chosen such that it corresponds to a drop
height of less than or equal to 50 cm, preferably less than or equal to 10
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cm. In practice, it is advantageous to choose this threshold value in a
range between 0.7 and 1.5 m/s, better still 0.8 to 1.2 m/s.
[0021] The locking device is advantageously attached on the runner such that a
manipulation of the mobile stopping element by the user is prevented
when the runner is mounted on the rail. The user thus cannot prevent the
stopping element from blocking the runner on the rail if the user falls.
[0022] With the same aim, it is further advantageous to attach the stopping
element on the runner such that the user cannot mechanically work on the
stopping element with a tool in order to block it, so as to prevent the
movement into the second, locking position when the runner is mounted
on the rail.
Brief description of the drawings
[0023] Embodiment examples of the invention are explained below with reference
to the drawings. There are shown in:
Fig. 1 the fall arrester for personal fall protection according to a first
embodiment of the invention in a schematic diagram;
Fig. 2 the fall arrester for personal fall protection according to a second
embodiment of the invention in blocked position;
Fig. 3 the fall arrester for personal fall protection according to a second
embodiment of the invention in released position;
Fig. 4 the fall arrester of Figure 2 in a three-dimensional representation;
Fig. 5 the housing of the speed-determining apparatus of Figure 4 in
section;
Fig. 6 the fall arrester for personal fall protection according to a fourth
embodiment of the invention, wherein the mechanical locking device is
blocked and stops the free movement of the runner;
Fig. 7 the fall arrester from Figure 6, wherein the locking device is in its
first, unlocked position in which it allows a free movement of the runner
along the guide rail;
Fig. 8 the fall arrester from Figure 6, wherein the electronic locking device
is blocked and stops the free movement of the runner;
Fig. 9 the fall arrester for personal fall protection according to a fifth
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embodiment mounted on a section of rail in a three-dimensional
representation;
Fig. 10 the fall arrester from Figure 9, wherein the locking device allows a
free movement of the runner along the guide rail;
Fig. 11 the fall arrester from Figure 9, wherein the electronic locking device
is blocked and stops the free movement of the runner;
Fig. 12 the fall arrester of Figure 9, wherein the mechanical locking device
is blocked and stops the free movement of the runner; and
Fig. 13 the fall arrester from Fig. 9 in a three-dimensional representation
without the rail.
Way(s) of carrying out the invention
[0024] A schematic diagram of a fall arrester 10 according to the invention of
a
personal fall protection means is represented in Figure 1. The schematic
diagram is simplified in order to explain the principle of a locking device
30. The fall arrester or the runner 10 is guided along a rail 12. The runner
is mounted such that it slides on the rail 12. Figure 1 does not
represent the means of the runner 10 by which it can slide on the rail 12.
In this regard, the rail 12 and the runner 10 can be designed according to
the state of the art. The runner 10 has a housing 20 with a front 14 and a
back 16. When the runner 10 is fitted on the rail 12, the back 16 faces the
rail 12 and the front 14 the user. The runner 10 has an anchor point 18 as
well as the locking device 30 which can prevent the runner 10 from sliding
on rail 12 at least in a downward movement if the speed of the runner 10
exceeds a predetermined threshold value. The anchor point 18 is
attached, in this schematic diagram, to the housing 20 of the runner 10,
and thus does not engage in the locking device 30 described below
independently of a stress exerted by the user.
[0025] The locking device 30 comprises a bolt 32 which is mounted sliding in
an
opening 34 in the runner 10. The bolt 32 can be in two positions. In a first
position, the bolt 32 is withdrawn as far as possible into the housing 20 of
the runner 10 and makes possible the free movement of the runner 10
along the rail 12. At intervals, the rail 12 has catching stops 106 in the
form
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of openings or catching stops 107 in the form of pawls (Fig. 2). In the
second position, the bolt 32 protrudes so far beyond the back 16 of the
runner 10 that it engages in one of the catching stops 106 of the rail 12
and thus blocks the movement of the runner 10 along the rail 12. A stop 38
is provided to limit the sliding of the bolt 32 in the direction of the rail
12.
The bolt 32 is stressed in the direction of the second, blocking position by
means of a compression spring 40. The housing 20 of the runner 10 is
designed such that it covers the whole locking device 30, and thus the
user has no access to the locking device 30 from the front 14 of the runner
10. The user is thereby prevented from engaging in the locking device 30
either intentionally or unintentionally. The fact that the bolt 32 protrudes
from the back 16 of the runner 10 is not a disadvantage, as the back 16 is
not accessible for the user when the runner 10 is sitting on the rail 12.
[0026] The locking device 30 furthermore has a holding device by which the
bolt
32 is held in the first, non-blocking position. The holding device consists of
a pin 42 which engages in a recess 44 of the bolt 32. The pin 42 can be
designed as a magnetic core of an electromagnet 46 and be preloaded by
a spring, not represented in Figure 1, into the recess 44 of the bolt 32. In
this situation, the electromagnet 46 is switched off. The holding device is
uncoupled by exciting the electromagnet 46, whereby the pin 42 is drawn
into the electromagnet 46 and, at the same time, pulled out of the recess
44 of the bolt 32. The preloaded bolt 32 is then moved by the spring 40
into the second, blocking position, and stops the free movement of the
runner 10 along the rail 12.
[0027] The locking device 30 is triggered if the sliding speed of the runner
10 in
the rail 12 exceeds a predetermined speed that is representative of a fall
situation. The speed of the runner 10 is determined with the help of an
electric generator 60 which is mounted on the runner 10. The electric
generator 60 has a rotor axis which is driven by a friction wheel 62 or a
roller that rolls along the rail 12. The friction wheel 62 can be fastened
directly on the axis of the rotor of the generator 60 or transmit the rotation
to the latter via a movement transmission system. The voltage or
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frequency of the electrical signal generated by the generator 60 typically
increases with the rotational speed of the rotor. An electronic control
system 70 is connected to the generator 60 and picks up its voltage or
frequency signal. It excites the electromagnet 46 and thus triggers the
locking device 30 as soon as the value generated by the generator 60,
characteristic of the speed of the runner 10, exceeds a previously defined
threshold value. The speed threshold value can be fixed or adjustable for
example via a potentiometer.
[0028] The electronic control system 70 can be an electronic card or printed
circuit which a person skilled in the art readily knows how to use. If for
example the value characteristic of the speed is the electrical voltage
delivered by the generator 60, the comparison can be drawn by means of
an electronic circuit.
[0029] The electrical energy that is generated by the generator 60 when the
runner 10 moves on the rail 12 can be used to supply electrical energy to
the electronic control system 70 and the electromagnet 46. In particular,
the electrical energy generated by the generator 60 can be stored in
capacitors in order to guarantee the control system 70 enough energy to
excite the electromagnet 46. The electrical energy provided by the
generator 60 can alone be enough to supply the control system 70 and the
electromagnet 46. The fall arrester 10 is thereby completely self-sufficient
and independent in relation to the energy supply.
[0030] If the runner 10 is blocked on the rail 12 after the bolt 32 has passed
into
the second, blocking position, the user can then reset the bolt 32 in the
non-blocking position by hand, for example by pressing on the end of the
bolt 32 from the rearward part of the rail 12 until the pin 42 again engages
in recess 44 of the bolt 32.
[0031] The second embodiment represented in Figures 2 and 3 of the fall
arrester
is also guided on the guide rail 12. The guide rail 12 is a C-profile,
wherein the opening edges of the C-profile act as guide flange. The runner
10 has, on both sides, guide grooves 82 that receive the guide flange of
the guide rail 12. Guide rollers 84 to 89 which roll along the outside and
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inside of the guide flange protrude in the guide grooves 82. The guide
rollers 84 to 89 are preferably made of plastic or elastomer or covered with
such a material, in order to limit the generation of noise when the runner
10 slides on the rail 12. The rollers 84 to 89 also ensure the positioning of
the runner 10 in relation to the rail 12 and consequently of the friction
wheel 62 on the rail 12.
[0032] Unlike in the first embodiment, here the central element of the locking
device 30 is a catch 100, rotatably housed in the runner 10, which can be
swivelled into a first and a second position. In the first position,
represented in Fig. 3, a detent lug 102 of the catch 100 does not engage in
the rail 12 and therefore allows a free upward and downward movement of
the runner 10 along the rail 12. In the second position, represented in Fig.
2, the detent lug 102 of the catch 100 engages in the catching stops 106,
107 of the rail 12 and thus blocks the downward movement of the runner
10. An upward movement of the runner 10 is also possible in the second
position, as the detent lug 102 of the catch 100, as a result of its bevelled
shape, can be moved over the catching stops 106, 107 of the guide rail 12
during the upward movement. A stop 108 on the runner 10 prevents the
catch 100 from moving beyond the second position. The stop 108 can be
designed fixed and in one piece with the runner 10. It can also be
adjustable, in order that the extent of the projection of the detent lug 102
of
the catch 100 beyond the back wall 16 of the runner 10 is adjustable. The
runner 10 can thereby be adapted to different rails 12 with larger or
smaller spaces between the catching stops 106, 107 from the back 16 of
the runner 10. The stop 108 is for example a headless screw screwed into
the runner 10.
[0033] The catch 100 is stressed in the direction of the second position. The
stressing means is preferably an elastic stressing element, for example a
spring 110, between the runner 10 and the catch 100. As an alternative,
the stressing on the catch 100 in the direction of the bottom of the rail 12
can be achieved only as a result of the gravity which acts on the catch
100.
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[0034] As in the first embodiment, the fall arrester 10 has a holding device
which
holds the catch 100 in the first position during normal operation and can be
uncoupled in order to make possible the movement of the catch 100 into
the second position. The holding device can be identical to that of the first
embodiment, except that the recess 44 is provided in the catch 100.
[0035] An advantageous variant of the holding device is represented in Figures
2
and 3. It comprises a magnetic base or permanent magnet 114 and an
electromagnet 112 with a metal or other surface which is suitable for the
permanent magnet 114 to adhere to it permanently when the
electromagnet 112 is not switched on. The permanent magnet 114 is
preferably fastened to the catch 100 and the electromagnet 112 to the
runner 10. The electromagnet 112 holds the catch 100 in the first position
as a result of the permanent magnet 114 magnetically adhering to the
corresponding surface of the electromagnet 112. The holding device is
uncoupled by switching the electromagnet 112 on in order to produce a
magnetic force which counteracts the magnetic adhesion of the permanent
magnet 114 and it is sufficient to release the permanent magnet 114 from
the corresponding surface of the electromagnet 112. The preloaded catch
100 is pivoted by the spring 110 into the second position, with the result
that the detent lug 102 of the catch 100 engages in one of the catching
stops 106, 107 of the guide rail 12 and thus stops the downwardly directed
movement of the runner 10 on the rail 12. The swivelling of the catch 100
into the second position results from the stress applied by the spring 110
or any other above-mentioned stressing means, but the pivoting speed
can advantageously be increased by magnetically repelling the permanent
magnet 114 away from the electromagnet 112, in order to ensure a faster
blocking of the runner 10 in rail 12.
[0036] As in the first embodiment, the locking device 30 is activated
according to
this second embodiment when the sliding speed of the runner 10 on the
rail 12 exceeds a predetermined threshold speed which is representative
of a fall situation.
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[0037] In the example represented, the electronic control system 70 and the
electric generator 60 are accommodated in the same housing 72. As
Figure 5 shows, the housing 72 also contains the friction wheel 62 which is
to roll along the front of the rail 12, as well as two further wheels or
rollers
64 and 66. The friction wheel 62 drives the rotor of the electric generator
60 by rotation, wherein the friction wheel 62 drives the roller 64 which in
turn drives the roller 66 on the rotor axis of the electric generator 60.
[0038] Moreover, a counter roller 68 is provided in order to ensure the
contact
between the friction wheel 62 and the rail 12. The counter roller 68 is to
roll
along the front wall of the rail 12 opposite the friction wheel 62. It is
preferably to be provided that the front wall of the rail 12 is clamped
elastically between the friction wheel 62 and the counter roller 68. For this,
the counter roller 68 can be elastically stressed against the friction wheel
62. Moreover, the counter roller 68 can be attached rotating on the end of
an arm 74 which is attached pivoting in relation to an axis 76 on the
housing 72. The end of the arm 74 which carries the counter roller 68 is
stressed in the direction of the friction wheel 62 by a compression spring
78 which is only represented in Figure 5. Finally, it is advantageous to
provide a device in order to absorb the play in order to ensure, e.g. should
the front of the rail 12 display changes in shape, that there is contact
between the friction wheel 62 and the rail 12. In the example represented,
this is achieved by mounting the housing 72 pivoting about an axis 80 on
the runner 10 together with the counter roller 68.
[0039] Of course, the guide means and the arrangement of the housing 72 with
the above-described components can also be used within the framework
of the first embodiment.
[0040] The catch 100 is arranged on the runner such that manual engagement by
the user is avoided. In a still more advantageous arrangement, the catch
100 can be arranged such that the user can be prevented from blocking
the catch 100 by using a tool, for example a screwdriver, between catch
100 and runner 10, in order to prevent a movement towards the rail 12. In
the example represented, the electromagnet 112 is accommodated in a
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housing 20 fastened on runner 10. More precisely, this housing 20 is
fastened on the front 14 of the runner 10 above the opening 34 in which
the catch 100 lies. In the mentioned example, the housing 20 covers only
part of the opening 34, namely the lower part with the detent lug 102 of the
catch 100 which lies opposite its pivot axis 120. The housing 20 thus
prevents the user from being able to intentionally stop the catch 100 from
engaging in the catching stops 106, 107 on the bottom of the rail 12 by
manually engaging in the free part of the catch 100 or by inserting a tool,
for example a screwdriver, into the opening 34 between the free end of the
catch 100 and the runner 10. In the part of the opening 34 not covered by
the housing 20, the user cannot grip or block the catch 100, as this does
not protrude beyond the front 14 and the play between the side walls of
the catch 100 and the side walls of the opening 34 is small enough to
prevent the user from inserting a finger or a tool, for example a
screwdriver. In a variant, the opening 34 is completely closed at the front
14 by the housing 20 or any other suitable means, for example a plate
attached to runner 10 above the part of the opening 34 not covered by
housing 20. The fact that the catch 100 can project in relation to the back
16 of the runner 10 is not a disadvantage from a safety point of view, as
the back 16 of the runner 10 is not accessible for the user when the runner
is mounted on the rail 12, as the walls of the rail 12 enclose the
rearward part of the runner 10.
[0041] If the locking device 30 has been triggered and the free movement of
the
runner 10 in the rail 12 is blocked, it is provided that the user can bring
the
catch 100 into the first position again in order to continue climbing down or
up the climbing device. In the example represented, the pawls or catching
stops 107 of the rail 12 cause during an upward movement of the runner
10 a sufficient pivoting movement of the catch 100 in the direction of the
first position, with the result that the permanent magnet 114 again
magnetically adheres to the corresponding surface of the electromagnet
112 because the electromagnet 112 is no longer excited. As soon as the
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catch 100 is in the first position, the fall arrester 10 is ready for use
again
for personal fall protection.
[0042] Figure 4 shows a three-dimensional representation of the fall arrester
10
according to this second embodiment. For reasons of clarity, the anchor
point 18 is not represented.
[0043] In a third, not represented embodiment, the fall arrester 10 has a
second,
mechanical locking device in order to block the sliding of the runner 10 in
the rail 12 if the user falls, wherein this second locking device corresponds
to the state of the art, as described for example in DE-U-295 01 716. The
second locking device comprises a further catch which can be swivelled
from a first position, in which it does not prevent the downward movement
of the runner 10 on the rail 12, into a second position, in which it blocks
the
downward movement of the runner 10 on the rail 12. In this case, the
anchor point 18 is attached on this second catch. The passage of the
second catch from the first position into the second is triggered by the
change to downward direction as the result of a pull exerted on the second
catch by the user via a connection means with which he is fastened to the
anchor point 18. The second locking device operates independently of the
first locking device 30 according to the first or second embodiment. If,
consequently, one locking device is defective, the second continues to
function. In particular, the second, conventional locking device further
represents a fall protection means should the first locking device not
function for example because of a failure of the electric generator 60 or the
control system 70. In this embodiment, the first locking device 30
according to the first or second embodiment and the second locking
device according to the state of the art can be attached in succession in
longitudinal direction on the same runner 10.
[0044] Figures 6, 7 and 8 represent a fall arrester 10 for personal fall
protection
according to a fourth embodiment which is a further development of the
second embodiment. The overall description of the second embodiment is
therefore valid for this fourth embodiment with the exception of the
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constituents which are individually listed below. For reasons of clarity, the
counter roller 68 has not been represented.
[0045] The fall arrester 10 has a catch which, unlike the catch 100 of the
second
embodiment, is designed in two parts. This two-part catch is composed of
a mechanical lever 104 and a detent lug 102 which are rotatably housed
independently of each other on the same axis 120. The mechanical lever
104 has the anchor point 18 to which the user is fastened via a connection
means. The holding device of the locking device 30 serves to hold the
detent lug 102 against the mechanical lever 104. For this, the holding
device can have an electromagnet 112 which is released by current
supply, as in the second embodiment. The electromagnet 112 is located
on the detent lug 102, while the permanent magnet 114 is fastened
opposite on the lever 104, or vice versa. If the holding device is coupled
on, the permanent magnet 114 adheres to the corresponding surface of
the electromagnet 112. During normal operation, the mechanical lever 104
and the detent lug 102 are therefore in fixed connection. The unit
consisting of the mechanical lever 104 and the detent lug 102 thus
functions similarly to a conventional catch according to the state of the art.
The fact that the user pulls on the anchor point 18 backwards or upwards
causes the two-part catch 102, 104 to be released from the catching stops
106, 107 on the bottom of the rail 12. This situation is represented in
Figure 7, in which the arrow 122 indicates the direction in which the tensile
stress is exerted on the anchor point 18 by the connection means between
the anchor point 18 and the user of the climbing protection system. This
tension goes in the opposite direction to the stress exerted on the detent
lug 102 by the spring 110.
[0046] On the other hand, the consequence of the fact that the user pulls
downwards on the anchor point 18, as is indicated by the arrow 122 in
Figure 6, is that the two-part catch 102, 104 is pressed in the direction of
the rail 12. The detent lug 102 therefore engages in the catching stops
106, 107 on the bottom of the rail 12, as is represented in Figure 6. The
detent lug 102 consequently blocks the downward movement of the runner
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on the rail 12. As a result of the bevelled shape of the catch 102, the
upwardly directed travel of the runner 10 on the rail 12 remains possible. It
is to be preferred that the lever 104 has a bearing surface 124 which is in
contact with a surface 126 of the detent lug 102 in order to transmit
shearing stresses of the mechanical lever 104 onto the detent lug 102 and
in order to prevent this from occurring via the permanent magnet 114 and
the corresponding surface of the electromagnet 112. For the rest, the
detent lug 102 is attached on the runner 10 in such a way that a
manipulation by the user is prevented. In the example represented, the
part of the mechanical lever 104 in the direction of the upper end of the rail
12 forms a fork at the level of the axis 120. The part of the detent lug 102
in the direction of the upper part of the rail 12 is attached between the
arms of the mechanical lever 104 which form the aforementioned fork. The
detent lug 102 does not protrude beyond the front surface of the
mechanical lever 104. Moreover, the play between the arms of the fork of
the lever 104 and the upper part of the detent lug 102 is small enough to
prevent the user from inserting a finger or a tool, for example a
screwdriver, there. The user therefore cannot grip this part of the detent
lug 102 or block it with the help of a tool. The whole of the remaining part
of the detent lug 102 extends below the lever 104. Therefore the user
cannot reach these areas of the detent lug 102 with his fingers either. The
chosen play between the end of the lever 104 and the lower end of the rail
12 and the runner 10 can be small enough that the user cannot insert his
finger there in order to hold the detent lug 102 back. A cover 128, not
represented in Figures 6 to 8, can be provided which limits the access to
the detent lug 102 still further. A possible embodiment of the cover 128 is
represented in Figure 12.
[0047] The housing 72 is attached to the front 14 of the runner 10. A friction
wheel 62 is provided for rolling along the front of the rail 12. The friction
wheel 62 is housed in the housing 72 and partially protrudes from this in
order to come into contact with the rail 12. The friction wheel 62 is
preferably mounted directly on the axis of the electric generator 60 in the
CA 02731080 2011-01-17
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housing 72. In the example represented, the housing 72 is mounted
pivoting in relation to an axis 80 on the runner 10. As a result of this
pivoting mounting, the play can be absorbed in order to ensure a
permanent contact between the friction wheel 62 and the front wall of the
rail 12 when the runner 10 slides on the rail 12. The housing 72 is
preferably elastically stressed, for example via a spring, about the pivot
axis 80 in the direction of rail 12 in order to ensure a permanent contact
with the rail 12, even if the latter should display any changes in shape.
[0048] As described with reference to the second embodiment of the fall
arrester,
the electronic control system 70 triggers the locking device 30 if the sliding
speed of the runner 10 on the rail 12 exceeds a threshold value above
which it can be assumed that the user finds himself in a fall situation. The
electronic control system 70 and the measurement of the sliding speed of
the runner 10 on the rail 12 by means of an electric generator 60 can be
designed in identical manner, as described with reference to the second
embodiment. In Figures 6 to 8, however, the housing 72 which contains
these components is attached to the upper end of the runner 10, which
makes it easier to connect the electronic control system 70 to the
electromagnet 112. Alternatively, it can be attached to the lower end, as is
represented for the second embodiment.
[0049] The effect of the uncoupling of the holding device is that the detent
lug 102
is detached from the mechanical lever 104, as represented in Figure 8.
The detent lug 102 is stressed in the direction of the bottom of the rail 12
by the spring 110 and engages in the catching stops 106, 107 on the
bottom of the rail 12 in order to block the downwardly directed movement
of the runner 10 on the rail 12. The upwardly directed travel of the runner
on the rail 12 continues to be possible in this situation.
[0050] The fall arrester 10 according to this fourth embodiment is used as
follows.
In normal use, the detent lug 102 is in fixed connection with the lever 104
via the holding device. When the user uses the fall arrester 10 in a
climbing system, he exerts a backwardly or upwardly directed tensile
stress on the anchor point 18, with the result that the two-part catch is kept
CA 02731080 2011-01-17
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away from the area of the catching stops 106, 107 on the bottom of the rail
12. This tension can be manual or caused by a connection means
between the user and the anchor point 18. This case is illustrated in Figure
7. If the user falls, in the case of locking devices 30 with a conventional
catch 100 a certain time passes until the catch 100 engages in the
catching stops 106, 107 on the bottom of the rail 12 due to the downwardly
directed tensile stress on the anchor point 18. The more time elapses until
the locking device 30 is triggered, the further the user falls in the event of
a
fall. The reaction time of the locking device 30 is reduced by the two-part
catch represented in Figures 6 to 8. As soon as the speed of the runner 10
on the rail 12 exceeds a previously defined speed, the electronic control
system 70 uncouples the holding system, before the two-part catch is
pressed into the catching stops 106, 107 of the rail 12 in a conventional
way, thus under the influence of the downwardly directed tension on the
anchor point 18. When the holding device is uncoupled, the detent lug 102
is detached from the lever 104 and stressed in the direction of the catching
stops 106, 107 of the rail 12 under the influence of the spring 110.
Consequently, the runner 10 on the rail 12 is blocked more quickly than
with conventional fall arresters. In order to achieve this effect, the speed
threshold value which is predetermined for the electronic control system
70 must, as explained above, be selected in suitable manner. Figure 8
illustrates the situation represented in which the fall arrester 10 stops the
user from falling, wherein the pull on the anchor point is still directed
backwards, while the detent lug 102, which is no longer connected to the
lever 104, is already engaging in the catching stops 106, 107 on the
bottom of the rail 12. In the same way, the fall arrester 10 remains
effective even when the user intentionally pulls the anchor point 18
backwards or upwards in order to prevent the catch 102 from engaging in
the catching stops 106, 107 of the rail 12. As soon as the speed of the
runner 10 exceeds the speed predetermined for the electronic control
system 70, the holding device is released and the detent lug 102 is
pressed into the catching stops 106, 107 of the rail 12, in order to block the
CA 02731080 2011-01-17
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movement of the runner 10 on the rail 12 despite the pulling movement by
the user on the anchor point 18.
[0051] In this embodiment, the holding device is automatically recoupled when
the mechanical lever 104 is likewise swivelled into the second position by
the weight of the user in the event of a fall, a short time after the holding
device is triggered, and is thereby brought back into contact with the
detent lug 102. The permanent magnet 114 then again magnetically
adheres to the corresponding surface of the electromagnet 112 because
the electromagnet 112 is already currentless again at the time. Since the
runner 10 is again stopped at this time and its speed thus lies below the
comparison threshold, the electromagnet 112 has been de-energized
again by the electronic control system 70.
[0052] Should a malfunction prevent the uncoupling of the holding device
during
the fall, if for example the generator 60 or the control system 70 were
defective, the detent lug 102 would nevertheless be forced to press into
the catching stops 106, 107 on the bottom of the rail 12 by the downward
pull exerted by the weight of the user on the anchor point 18 and thus on
the lever 104. The locking device 30 thus blocks the runner 10 in this case
also on the rail 12, in a way such as is known in the state of the art.
[0053] Figures 9 to 12 show the fall arrester 10 in a fifth embodiment which
represents a further development of the fourth embodiment. The overall
description of the fourth embodiment is therefore valid for this fifth
embodiment with the exception of the constituents which are individually
listed below.
[0054] Buffers 90 and 92 are fastened to the bottom of the lateral grooves 82.
These buffers absorb impacts and mechanical oscillations between the
bottom of the lateral grooves of the rail 12 and the runner 10 during
movements on the rail 12 and limit the noise caused during the movement
of the runner 10. The buffers 90, 92 can also be used in the above
embodiments.
[0055] The catch is again designed in two parts, wherein in this case the
detent
lug 102 is rotatably housed with two fork-shaped arms on the axis 120.
CA 02731080 2011-01-17
The lever 104 is mounted between the arms of the fork of the detent lug
102. As an alternative, the reverse configuration, as described in the fourth
embodiment, can also be used.
[0056] Initially the spring 110 does not stress the detent lug 102 directly
towards
the rail 12, but only the lever 104, which then transmits the stress onto the
detent lug 102. It is the task of another spring 130 to press the detent lug
102 against the catching stops 106, 107 of the rail 12 when the lever 104
is kept at a distance from the rail 12 and the detent lug 102 is detached
from the lever 104. This case is represented in Figure 11.
[0057] The advantage of two springs 110 and 130 is that the reaction speed of
the locking device 30 is accelerated in certain cases. If, in the event of a
fall of the user, the movements of the detent lug 102 and of the
mechanical lever 104 are superimposed, the detent lug 102 is directly
stressed by the spring 130 and at the same time indirectly stressed by the
spring 110. Thus, the time required to swivel the detent lug 102 from the
first into the second position, thus the reaction time of the locking device
30, is reduced.
[0058] The measures that are taken to prevent the user from working on the
detent lug 102 or blocking it with a tool are similar to those described with
reference to the fourth embodiment. The cover 128 is also to be provided
in order to prevent any insertion of a tool or a finger of the user, should
the
play between the part of the detent lug 102 which faces the lower part of
the rail 12 and the opposite edge of the opening 34 of the runner 10 be
large enough. The cover is shown schematically only in Figures 10 to 12.
[0059] As in the fourth embodiment, the housing 72 (not represented) including
generator 60 and friction wheel 62 can be attached to the front 14 of the
runner 10 in a recess 73.
[0060] The mode of operation of the protection device according to the fifth
embodiment is identical to the mode of operation of the fourth embodiment
with the exception of the aforementioned roller of the springs 110 and 130.
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[0061] Of course, this invention is not limited to the described and
represented
embodiments, but can have many variants which are available to a person
skilled in the art.
[0062] In the various embodiments described, the electronic control system 70
can be provided to establish, in addition to the speed, also the movement
direction of the runner 10 on the rail 12 in order not to cause an uncoupling
of the holding system if the speed threshold is exceeded during ascent.
Blocking of the runner 10 on the rail 12 when the runner 10 travels
upwards, i.e. in a direction that does not correspond to a fall, is thereby
prevented. However, it is easier not to establish this and to always trigger
the locking device 30 as soon as the speed threshold is exceeded,
completely regardless of the direction in which the runner 10 is sliding.
This speed threshold is normally not reached when the user is climbing up
a climbing system and in this case the runner 10 is thus not blocked on the
rail 12. Because it is bevelled, the detent lug 102 can normally travel over
the catching stops 106, 107 in any event.
[0063] In the various embodiments, the speed is measured with the help of an
electric generator 60. Alternatively, other means of measuring speed can
be used. In particular, it is possible to use an inductive, capacitive or
optical speed sensor which can cooperate with the catching stops 106,
107 on the bottom of the rail 12 or other elements which are incorporated
into the rail 12 for this purpose. However, the use of an electric generator
60 is advantageous because it can also be used to generate just the
electrical energy necessary for the operation of the fall arrester 10. In the
various described embodiments, the electronic control system 70 is
provided to activate the locking device 30 when the speed threshold is
exceeded by the runner 10. Of course, the control system 70 can also be
used to already activate the locking device 30 when the speed limit is
reached.
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List of reference numbers
Fall arrester/runner 80 Pivot axis
12 Guide rail 82 Guide grooves
14 Front of the runner 84 Guide roller
16 Back of the runner 85 Guide roller
18 Anchor point 86 Guide roller
Housing 87 Guide roller
Locking device 88 Guide roller
32 Bolt 89 Guide roller
34 Opening 90 Buffer
38 Stop 92 Buffer
Spring 100 Catch
42 Pin 102 Detent lug
44 Recess 104 Mechanical lever
46 Electromagnet 106 Catching stops
60 Generator 107 Catching stops
62 Friction wheel 108 Stop
64 Roller 110 Spring
66 Roller 112 Electromagnet
68 Counter roller 114 Permanent magnet
70 Control system 120 Pivot axis
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72 Housing 122 Direction of the tensile stress
73 Recess 124 Bearing surface
74 Arm 126 Surface
76 Axis 128 Cover
78 Compression spring 130 Spring
