U.S. patent application number 13/009948 was filed with the patent office on 2012-07-26 for padlock for securing and monitoring a switch.
This patent application is currently assigned to ABUS August Bremicker Soehne KG. Invention is credited to Bernhard Garthe.
Application Number | 20120186308 13/009948 |
Document ID | / |
Family ID | 46543115 |
Filed Date | 2012-07-26 |
United States Patent
Application |
20120186308 |
Kind Code |
A1 |
Garthe; Bernhard |
July 26, 2012 |
Padlock for securing and monitoring a switch
Abstract
A padlock for securing and monitoring a switch of an industrial
plant has a lock housing of plastic, furthermore a hoop which is
displaceably held at the lock housing and a lock cylinder which is
arranged in the lock housing and can selectively be brought from an
open position into a locked position to lock the hoop to the lock
housing. An RFID transponder is arranged in the lock housing. A
securing and monitoring system for a switch of an industrial plant
includes at least one such padlock and a mobile RFID reading device
or an RFID reading device permanently attached in the environment
of the switch, said RFID reading device being configured to read
out the RFID transponder of the padlock.
Inventors: |
Garthe; Bernhard;
(Gevelsberg, DE) |
Assignee: |
ABUS August Bremicker Soehne
KG
Wetter-Volmarstein
DE
|
Family ID: |
46543115 |
Appl. No.: |
13/009948 |
Filed: |
January 20, 2011 |
Current U.S.
Class: |
70/35 ;
70/20 |
Current CPC
Class: |
E05B 67/02 20130101;
H01H 9/281 20130101; E05B 39/04 20130101; Y10T 70/413 20150401;
Y10T 70/446 20150401; F16P 3/08 20130101; E05B 67/24 20130101; G07C
9/00309 20130101 |
Class at
Publication: |
70/35 ;
70/20 |
International
Class: |
E05B 67/06 20060101
E05B067/06; E05B 47/00 20060101 E05B047/00; E05B 67/02 20060101
E05B067/02 |
Claims
1. A padlock for securing and monitoring a switch of an industrial
plant, having a lock housing of plastic, furthermore having a hoop
which is displaceably held at the lock housing, and having a lock
cylinder which is arranged in the lock housing and can selectively
be brought from an open position into a locked position to lock he
hoop to the lock housing, wherein an RFID transponder is arranged
in the lock housing.
2. A padlock in accordance with claim 1, wherein the RFID
transponder is surrounded at all sides in the lock housing.
3. A padlock in accordance with claim 1, wherein the lock cylinder
has a longitudinal shape having a longitudinal axis, wherein the
RFID transponder is arched with respect to the longitudinal axis of
the lock cylinder.
4. A padlock in accordance with claim 3, wherein the RED
transponder extends at least along a part of the length of the lock
cylinder and at least along a part of the periphery of the lock
cylinder.
5. A padlock in accordance with claim 1, wherein the RFID
transponder is arranged spaced apart from the lock cylinder.
6. A padlock in accordance with claim 1, wherein the padlock has a
housing part which is secured in or at the lock housing, wherein
the RFID transponder is arranged in an intermediate space between
the lock housing and the housing part.
7. A padlock in accordance with claim 6, wherein the RFID
transponder is received in a recess of the lock housing or of the
housing part in form-fitted manner.
8. A padlock in accordance with claim 6, wherein the housing part
also comprises plastic.
9. A padlock in accordance with claim 6, wherein the lock housing
and the housing part are secured to one another by mean of a
releasable securing device, wherein the RFID transponder is
captured between the lock housing and the housing part as long as
the lock housing and the housing part are secured to one
another.
10. A padlock in accordance with claim 9, wherein the securing
device is only accessible and releasable when the lock cylinder is
brought into the open position by means of an associated key.
11. A padlock in accordance with claim 10, wherein a limb of the
hoop projects into a hoop receiving passage of the lock housing or
of the housing part when the hoop i lock to the lock housing,
wherein the limb of the hoop can be removed from the hoop receiving
passage when the lock cylinder is brought into the open position,
and wherein the releasable securing device which secures the lock
housing and the housing part to one another is arranged at the end
of the hoop receiving passage.
12. A securing and monitoring system for a switch of an industrial
plant, having at least one padlock which has a lock housing of
plastic and has an RFID transponder in the lock housing, wherein
the padlock is fastened to the switch, furthermore having a
reference RFID transponder which is permanently fastened in the
environment of the switch, and having a mobile RFID reading device
which is configured to read out the RFID transponder of the padlock
and the reference RFID transponder.
13. A securing and monitoring system in accordance with claim 12,
wherein the RFID reading device is configured to store a piece of
identification information read out of the RFID transponder of the
padlock and a piece of identification information read out of the
reference RFID transponder together with a piece of time
information.
14. A securing and monitoring system for a switch of an industrial
plant, having at least one padlock which has a lock housing of
plastic and has an RFID transponder in the lock housing, wherein
the padlock is fastened to the switch, and having a reference RFID
transponder which is permanently fastened in the environment of the
switch and which is configured to read out the RFID transponder of
the padlock at predetermined times.
15. A securing and monitoring system in accordance with claim 14,
wherein the RFID reading device is configured to store a piece of
identification information read out of the RFID transponder of the
padlock together with a piece of time information.
16. A padlock in accordance with claim 1, wherein the RFID
transponder is a passive component without integrated energy supply
and is operationally independent from both the lock cylinder and
the hoop.
Description
[0001] The invention relates to a padlock for securing and
monitoring a switch of an industrial plant. The invention further
relates to a securing and monitoring system for a switch of an
industrial plant which includes at least one padlock.
[0002] A particular area of application of a padlock is in the
field of occupational safety. There is the risk in connection with
the servicing of industrial plants, for example, of a production
machine, that the industrial plan deactivated for the purpose of
service work is activated again by accident while the servicing
work is still continuing. A substantial danger for the service
engineer can result from this. It is therefore customary that the
service engineer moves a switch associated with the industrial
plant to an OFF position for the duration of the service work and
secures it in this position, i.e, the switch is directly blocked or
access to the switch is blocked. The named switch is typically an
energy supply switch, for example a main electrical switch of a
control device or of an energy supply device of the industrial
plant (e.g. power switchbox). Alternatively to this, the named
switch can, for example, be a valve of a liquid line or of a gas
line.
[0003] In order effectively to avoid an accidental activation of
the industrial plant by another person, each service engineer hangs
a padlock on the named switch or on a blocking device associated
with the switch before starting his work and locks said padlock.
The switch is hereby secured in its OFF position, i.e. the switch
cannot be moved accidentally back into an ON position by another
person. When the service engineer has ended his work, he unlocks
his padlock again and releases it from the switch. Each service
engineer usually has his own individual padlock (or a plurality of
his own individual padlocks) associated with him.
[0004] This procedure is also called locking out. The padlock used
is accordingly called a lockout lock. The document U.S. Pat. No.
5,449,867 shows such a securing of an electric rocker switch by
means of a padlock. It is known from the document U.S. Pat. No.
3,171,908 to secure the position of a rotary switch by means of a
padlock.
[0005] So that a plurality of service engineers can block and
release the switch again independently of one another, a plurality
of receivers (e.g. eyelets) can be provided at the switch for
hanging a plurality of lockout locks. This is known from the
document U.S. Pat. No. 6,388,213, for example. If only a single
receiver for a lockout lock is provided, a securing claw can be
used which is hung into the respective eyelet of the switch or of
the associated blocking device and which in turn has a plurality of
hang-in eyelets for a respective padlock. Only when the last
padlock has been removed from the securing claw can the securing
claw be removed from the switch so that it can again be brought
into the ON position. Such a securing claw for use at an electric
switchbox is known, for example, from documents U.S. Pat. Nos.
6,396,008, 5,365,757 and 3,667,259.
[0006] It is known in connection with such a securing of a switch
of an industrial plant to equip the lockout lock used with a
housing of plastic, with a hoop being displaceably held at the lock
housing and with a lock cylinder being arranged in the lock
housing. The lock cylinder can selectively be brought from an open
position into a locked position to lock the hoop to the lock
housing after the hoop has, for example, been hung into an eyelet
of the switch. By forming the lock housing from plastic, a
particularly light padlock results which is of advantage in the use
as a lockout lock since the service engineers occasionally carry a
plurality of lockout locks simultaneously. A housing of plastic can
also contribute to a desired electrical insulation. By the use of a
plastic housing, there is furthermore a particularly simple
possibility of color marking the padlock. The smaller stability of
a plastic housing in comparison with a lock housing made of metal
does not represent any serous disadvantage in a lockout lock since
the padlock only serves the purpose of securing a switch against
unintentional actuation, but not, for example, as theft protection.
Such a lockout lock having a housing of plastic is known, for
example, from documents U.S. Pat. Nos. 7,278,283 and 5,755,121.
They are here cases of simple, purely mechanical padlocks.
[0007] It is an object of the invention to provide a padlock and a
corresponding securing system which enable a reliable securing and
monitoring of a switch of an industrial plant with a simple
design.
[0008] This object is satisfied by a padlock having the features of
claim 1 and in particular by a padlock for securing and monitoring
a switch of an industrial plant having a lock housing made of
plastic, furthermore having a hoop which is displaceably held at
the lock housing and having a lock cylinder which is arranged in
the lock housing and can selectively be brought from an open
position into a locked position to lock the hoop to the lock
housing, wherein an RFID transponder is also arranged in the lock
housing.
[0009] It is possible to check and document in a simple manner by
means of the RFID transponder arranged in the housing of the
lockout lock, while using an associated reading device, whether the
respective lockout lock is or was arranged at a switch of an
industrial plant at a given time to secure the switch. For this
purpose, the padlock used can have a simple mechanical design since
the RFID transponder can be inserted into the padlock as a separate
autonomous unit. The padlock can therefore have a purely mechanical
locking function which is independent of the electronic system of
the RFID transponder. Due to the arrangement of the RFID
transponder in a plastic housing, a radio communication can take
place with an associated reading device substantially without
interference. At the same time, the RFID transponder is reliably
protected against damage and contamination. This is an important
aspect in the use of the padlock as a lockout lock since the
padlock can be exposed to great strain by blows and/or wear if it
is arranged at a switch of an industrial plant and is also taken
along by the service engineer (for example hanging on a belt) when
not in use.
[0010] The arrangement of the RFID transponder in the lock housing
can take place in a variety of manners. The lock housing can, for
example, form an outer cover into which the RFID transponder is
integrated, in particular by overcasting or overmolding. It is
alternatively possible, for example, to receive the RFID
transponder releasably in the lock housing as will be explained in
the following.
[0011] An RFID transponder is a receiver and transmitter device
which receives an interrogation signal at a predetermined radio
frequency and hereupon transmits a predetermined identification
signal (for example an identification number encoded in a radio
signal). This process is called RFID (radio frequency
identification). For this purpose, the RFID transponder has at
least one antenna, an electronic circuit coupled hereto and a
non-volatile memory in which the predetermined identification
number is stored. If an associated reading device generates an
electromagnetic alternating field with a suitable frequency and
transmits it to the RFID transponder (interrogation signal), the
antenna of the RFID transponder takes on the electromagnetic energy
of the alternating field, whereby the transmission of the named
identification signal is triggered (in turn via the antenna). For
this purpose, the electronic circuit of the RFID transponder does
not have to have any energy supply of its own, but can rather take
the required electric energy from the received alternating field.
The output identification signal is imprinted into the alternating
field generated by the reading device by field attenuation such
that the reading device can decode the identification signal of the
RFID transponder. Such an RFID transponder is known, for example,
from the document U.S. Pat. No. 7,205,899.
[0012] It can be found and/or documented in a simple manner by the
reading of the identification signal of an RFID transponder
combined with a lockout lock which lockout lock (corresponding to a
specific service engineer) is or was fastened to a switch of an
industrial plant at a given time. It is also possible in this
respect simultaneously to detect a plurality of RFID transponders
by means of a single associated reading device, i.e. the presence
of a plurality of different RFID transponders or lockout locks can
simultaneously be determined and/or documented. A control device
associated with the switch or with the respective industrial plant
can additionally be supplied with monitoring signals (redundant
possibility of monitoring the switch state) on the basis of the
information obtained by means of the reading device (e.g.
identification number and date/time). Which lockout locks were
arranged at the respective switch of the industrial plant at which
time can alternatively or additionally be documented, for example
for the case of an industrial accident (accident clarification,
liability).
[0013] In accordance with an advantageous embodiment, the RFID
transponder is enclosed on all sides within the lock housing. A
particularly effective protection of the RFID transponder from
mechanical damage and/or contamination is hereby ensured. The
surrounding of the RFID transponder at all sides preferably takes
place by cooperation of the lock housing with a further part of the
padlock, in particular having a further housing part (e.g. inner
housing or outer housing part).
[0014] In accordance with a further embodiment, the lock cylinder
of the padlock has a longitudinal shape with a longitudinal axis
which typically corresponds to the axis of rotation of a rotatable
cylinder core of the lock cylinder. The lock cylinder can be
configured, for example, as a profile cylinder, in particular as a
replaceable profile cylinder. The RFID transponder is arched with
respect to the longitudinal axis of the lock cylinder in this
embodiment. In other words, the RFID transponder extends in curved
shape about the lock cylinder in cross-section (in a normal plane
to the longitudinal axis). A particularly advantageous angular
characteristic of the RFID transponder hereby results, i.e. the
RFID transponder can cooperate with an associated reading device in
a large angular range. A reliable communication with an associated
RFID reading device can in particular hereby be achieved
irrespective of whether the front side or the rear side of the
padlock faces the RFID reading device. The lock cylinder, which is
typically made from metal, in this respect does not prove to be a
disturbance since the lock cylinder can be arranged within the arch
formed by the RFID transponder, i.e. the RFID transponder can
peripherally surround the lock cylinder completely or partly.
[0015] The RFID transponder can in particular extend along at least
a part of the length of the lock cylinder and along at least a part
of the periphery of the lock cylinder. In this respect, the RFID
transponder does not have to contact the lock cylinder, but is
rather preferably arranged spaced apart from it (in the radial
direction with respect to the longitudinal axis of the lock
cylinder). A particularly good reception and transmission
characteristic of the RFID transponder is hereby achieved, whereas
the accommodation of the RFID transponder in the lock housing can
be realized in the manner of a unit "wound" around the lock
cylinder in a simple construction manner and with minimal space
requirements.
[0016] It is of advantage if the RFID transponder is arranged
spaced apart from the lock cylinder. Investigations have shown that
a particularly good angular characteristic of the RFID transponder
is achieved when the RFID transponder does not directly contact the
lock cylinder, but is rather arranged at a specific spacing from
the lock cylinder. This in particular applies when the RFID
transponder is arched with respect to the longitudinal axis of the
lock cylinder, as explained above.
[0017] If the padlock has a further housing part in addition to the
lock housing, said further housing part can be secured in or at the
lock housing (for example received therein), with the RFID
transponder being arranged in an intermediate space between the
lock housing and the further housing part. This allows a
particularly simple and fast fastening of the RFID transponder in
the lock housing since the RFID transponder only has to be placed
into the lock housing or into the further housing part before the
lock housing and the housing part are secured to one another and
the RFID transponder is thus captured in the lock housing.
Furthermore, an advantageous spacing between the RFID transponder
and the lock cylinder can hereby be realized in a simple
manner.
[0018] The RFID transponder can in particular be received in
form-fitted manner in a cut-out of the lock housing or of the
further housing part provided for this purpose to ensure a
substantially clearance-free seating of the RFID transponder in the
lock housing.
[0019] It is preferred with respect to the named further housing
part if it is also made from plastic. A large range and a wide
angular characteristic of the RFID transponder is hereby supported
even better. It is, however, also possible to produce the named
housing part from metal, provided that an electric insulation from
the components of the RFID transponder is ensured (for example by a
plastic enveloping of the RFID transponder).
[0020] In accordance with a preferred embodiment, the lock housing
and the named further housing part are secured to one another by
means of a releasable securing device (for example by means of a
screw), with the RFID transponder being captured between the lock
housing and the housing part as long as the lock housing and the
housing part are secured to one another by means of the named
securing device. The RFID transponder is hereby captively secured
in a reliable manner in the lock housing. The RFID transponder can
nevertheless subsequently be replaced, for example to allocate a
different identification number to the respective lockout lock.
[0021] It is in this respect particularly advantageous if the named
securing device is only accessible when the authorized user has
brought the lock cylinder into the open position by means of an
associated key. It is hereby possible for the authorized user to
replace the RFID transponder as required. However, as long as the
lock housing and the housing part are secured to one another by
means of the named securing device and the padlock is locked, the
RFID transponder is captured in an unreachable manner between the
lock housing and the housing part so that a high manipulation
security is ensured with respect to the association of a
predetermined RFID transponder with the respective padlock.
[0022] It is preferred with respect to the RFID transponder if it
has two antennas. The sensitivity and the angular characteristic of
the RFID transponder can hereby be even further improved.
[0023] The above-named object is also satisfied by a securing and
monitoring system for a switch of an industrial plant which
includes at least one padlock having a lock housing made of plastic
and having an RFID transponder arranged in the lock housing,
wherein the padlock can be fastened to the switch of the industrial
plant, with the securing and monitoring system furthermore having a
reference RFID transponder which is permanently fastened in the
environment of the switch and having a mobile RFID reading device
which is configured to read out the RFID transponder of the padlock
and the reference RFID transponder fastened in the environment of
the switch.
[0024] It is possible by such a securing and monitoring system, on
the one hand, to detect the presence of a lockout lock by means of
the RFID reading device, namely in that the RFID transponder of the
lockout lock is detected. On the other hand, a spatial association
of the lockout lock with the respective switch of the industrial
plant can be established in that the RFID reading device
simultaneously detects the reference RFID transponder mounted in
the vicinity of the switch. The presence of a specific lockout lock
at the switch can thus be reliably and reproducibly detected by
mans of an RFID reading device, whereby a conclusion can be drawn
that the corresponding service engineer has attached his lockout
lock properly to the switch.
[0025] The named RFID reading device can in particular be
configured to store a piece of identification information read out
of the RFID transponder of the lockout lock and a piece of
identification information read out of the reference RFID
transponder together with a piece of time information (date/time),
in particular in a non-volatile memory. The associated time
information can, for example, be derived from an integrated clock
of the RFID reading device.
[0026] The above-named object is also satisfied by a securing and
monitoring system for a switch of an industrial plant which has at
least one padlock having a lock housing made of plastic and having
an RFID transponder arranged in the lock housing, wherein the
padlock can be fastened to the switch of the industrial plant, and
wherein the securing and monitoring system has an RFID reading
device which is permanently fastened in the environment of the
switch and which is configured to read out the RFID transponder of
the padlock at predetermined times.
[0027] In this embodiment, the need to bring the mobile RFID
reading device into the proximity of the switch at predetermined
times to detect any lockout locks or their RFID transponders which
may be present. Instead, an RFID reading device mounted permanently
in the proximity of the switch can detect the presence of one or
more lockout locks at the switch by an automatic check at regular
time intervals.
[0028] The permanently fastened RFID reading device can in
particular be configured to store a piece of identification
information read out of the RFID transponder of the lockout lock
together with a piece of time information, in particular in a
non-volatile memory. A particularly reliable and complete
documentation is hereby possible on which lockout locks were
located at the switch at which times.
[0029] Alternatively or additionally, the piece of information read
out of the RFID transponder of the lockout lock can be transmitted
to a central storage and/or evaluation device. The central storage
and/or evaluation device can in this respect receive the signals
from a plurality of stationary RFID reading devices which are
associated with different switches of the industrial plant.
[0030] In another respect, in the above-explained securing and
monitoring systems, the respective padlock can be further developed
in accordance with one of the embodiments which were likewise
explained above for a lockout lock in accordance with the
invention.
[0031] The invention will be explained in the following only by way
of example with reference to the drawings. Elements which are the
same or of the same kind are marked by the same reference numerals
therein.
[0032] FIG. 1 shows a padlock in an exploded view;
[0033] FIG. 2 shows a padlock in a cross-sectional view;
[0034] FIG. 3 shows an inner housing with an RFID transponder in a
perspective view;
[0035] FIG. 4 shows a schematic representation of a securing and
monitoring system for a switch of an industrial plant; and
[0036] FIG. 5 shows a further securing and monitoring system in a
schematic representation.
[0037] The padlock shown in FIG. 1 has a lock body 11 and a hoop
13. The hoop 13 has a U shape with one shorter limb and one longer
limb. An inwardly facing locking recess 15 is formed at both limbs
of the hoop 13. Furthermore, a ring groove 17 with an abutment head
19 adjacent to it is provided at the free end of the longer
limb.
[0038] The lock body 11 has a lock housing 21 and a further housing
part which is configured as an inner housing 23 in the embodiment
shown. The lock housing 21 and the inner housing 23 comprise
plastic. The inner housing 23 can be inserted into the lock housing
21 and can be fixed to the lock housing 21 by means of a securing
screw 25, as will be explained in the following. The lock housing
21 and the inner housing 23 accommodate a lock cylinder 27 and a
locking mechanism 29 via which the lock cylinder 27 cooperates with
the hoop 13.
[0039] The lock cylinder 27 has a cylinder core 31 having a keyway
33. The cylinder core 31 is rotatably mounted within a cylinder
housing 35 with respect to an axis of rotation A (FIG. 2), wherein
a rotary actuation is only possible when an associated key is
introduced into the keyway 33. The cylinder core 31 has a driver
projection 37 at the rear side.
[0040] The locking mechanism 29 includes a rotational bolt 39 and
two blocking balls 41. The rotational bolt 39 has a substantially
hollow cylindrical shape with an engagement projection 43 at the
inner side which permits a rotationally fixed coupling to the
driver projection 37 of the lock cylinder 27. The rotational bolt
39 has, at the outer side, two receiving recesses 45 which can
partly accept the blocking balls 41 on an opening actuation of the
lock cylinder 27 and thus of the rotating bolt 39. At the
periphery, in each case adjacent to the receiving recesses 45, the
rotational bolt 39 forms locking sections 47 by which the blocking
balls 41 can be held in a blocking engagement with the locking
recesses 15 of the hoop 13.
[0041] The padlock shown in FIG. 1 selectively allows by a
corresponding actuation of the lock cylinder 17 the locking of the
hoop 143 to the lock body 11 (locking position of the lock cylinder
27) or the release of the shorter limb of the hoop 13 from the lock
body 11 (open position of the lock cylinder 27), for example to be
able to introduce the hoop 13 into an eyelet or to remove it
therefrom. The padlock shown is in particular suitable for use as a
lockout lock.
[0042] In accordance with the invention, an RFID transponder is
arranged within the lock housing 21 and is configured in the
embodiment shown here as a flexible unit whose antenna and
electronic components are received in a flexible film. The RFID
transponder 48 is thus U-shaped in cross-section and arched with
respect to the longitudinal axis of the lock cylinder 27 (axis of
rotation A in accordance with FIG. 2). The RFID transponder is in
this respect arranged radially spaced apart from the lock cylinder
27.
[0043] FIG. 2 shows a cross-sectional view of a possible embodiment
of a padlock in accordance with FIG. 1 in a mounted state and with
a locked hoop 13. The inner housing 23 is pushed into the lock
housing 21 and is fixed to the lock housing 21 by means of the
securing screw 25 for the installation of the padlock. The lock
cylinder 27, the locking mechanism 29 and the RFID transponder 48
are thereby captured in the lock housing 21. The fastening screw 25
cooperates with a nut 49 rotationally fixedly inserted into the
inner housing 23. The securing screw 25 is inserted into a hoop
receiving passage 51 of the lock housing 21 which is closed by the
hoop 13 when the hoop 13 is locked to the lock body 11--as shown in
FIG. 2. The nut 49 is covered by means of a cover 53. Provided that
the lock cylinder 27 has been brought into the open position and
the shorter limb of the hoop 13 has been removed from the hoop
receiving passage 51, the securing screw 25 can again be released
from the nut 49 to remove the inner housing 23 from the lock
housing 21. The RFID transponder 48 can hereby also be
retroactively replaced.
[0044] To fix the securing screw 25 permanently or to make a
subsequent opening of the lock housing 21 and any replacement of
the RFID transponder 48 recognizable, the securing screw 25 in the
respective hoop receiving passage 51 can be provided with a lacquer
film or with an adhesive, for example with Loctite (registered
trademark of Henkel Corporation, USA).
[0045] FIG. 2 shows a state of the padlock in which the hoop 13 is
locked and is thus secured against removal from the lock body 11.
The locking sections 47 of the rotational bolt 39 hold the blocking
balls 41 in blocking engagement with the locking recesses 15 of the
hoop 13 for this purpose. To unlock the padlock, a rotational
opening actuation by means of an associated key 55 is required. The
driver projection 37 of the lock cylinder 27 and the rotational
bolt 39 are hereby rotated by 90.degree. so that a respective
receiving recess 45 of the rotational bolt 39 is rotated into the
region of the blocking balls 41. The blocking balls 41 can thus
move back out of the locking recesses 15 of the hoop 13. The hoop
13 can now be pulled out of the lock body 11 axially until the
abutment head 19 of the longer hoop limb abuts the respective
blocking ball 41. The shorter limb of the hoop 13 now already
projects out of the lock body 11. The hoop 13 can now be rotated
about the longitudinal axis of the longer hoop limb. A repeated
locking of the hoop 13 to the lock body 11 takes place in the
reverse order.
[0046] The cross-sectional view in accordance with FIG. 2 allows it
to be recognized that the RFID transponder 48 is received in a
recess 57 of the inner housing 23.
[0047] FIG. 3 shows a perspective view of a possible embodiment of
an inner housing 23 of the padlock in accordance with FIG. 1 or
FIG. 2. The RFID transponder 48 is shown which is curved in U shape
and which is inserted into an outer recess 57 of the inner housing
23 in form-fitted manner. In this respect, the RFID transponder 48
surrounds at a specific radial spacing a central recess 59 of the
inner housing 23 which is provided for the form-fitted reception of
a lock cylinder 27 in the assembled state of the padlock. It can be
recognized in FIG. 3 that the RFID transponder then extends--viewed
in a radial projection with respect to the axis of rotation A in
accordance with FIG. 2--along a part of the length of the lock
cylinder 27 and along a part of the periphery of the lock cylinder
27.
[0048] Since the respective padlock in accordance with FIGS. 1 and
2 is provided with an RFID transponder 48, a piece of
identification information can, as required, be read out of the
RFID transponder 48 by means of an associated RFID reading device,
said piece of identification information allowing a reliable
identification and localization of the respective padlock. The
padlock is hereby particularly well suited for use as a lockout
lock for securing an electric switch or other switch of an
industrial plant. On the one hand, a switch position can namely be
blocked by means of the locked hoop 13. On the other hand, it can
be monitored and documented by reading out the piece of
identification information stored in the padlock which padlock is
or was arranged at the switch at which time. This will be explained
in more detail in the following with reference to two possible
embodiments.
[0049] FIG. 4 shows a securing and monitoring system for a switch
61 of an industrial plant. This securing and monitoring system
includes a padlock 63 whose hoop 13 is hung into a blocking device
65 of the switch 61, for example into an eyelet. The padlock 63 has
an RFID transponder 48, as explained in connection with FIGS. 1 to
3.
[0050] The securing and monitoring system in accordance with FIG. 4
furthermore includes a reference RFID transponder 67 permanently
mounted at the switch 61 or in the proximity of the switch 61. The
securing and monitoring system furthermore includes a mobile RFID
reading device 69. It has a transmission and reception antenna 71,
a control and evaluation circuit 73 coupled hereto, a non-volatile
memory 75 and an energy supply device 77 (e.g. an electric
battery).
[0051] An interrogation signal can be transmitted by means of the
RFID reading device 69, said interrogation signal being an
electromagnetic alternating field of a predetermined frequency. In
response to this interrogation signal, both the RFID transponder 48
of the padlock 63 and the reference RFID transponder 67 output a
respective identification signal which includes a piece of
individual identification information for the respective RFID
transponder 48 and 67 respectively. The respective identification
signal can be received and decoded by the mobile RFID reading
device 69. The respective received and decoded piece of
identification information is stored in the non-volatile memory 75,
preferably together with a piece of associated time
information.
[0052] The switch 61 can thus be monitored by means of the mobile
RFID reading device 69 as to whether the padlock 63 having the RFID
transponder 48 (and/or another padlock) is also detected at a time
at which the RFID reading device has identified the reference RFID
transponder 67. The securing state of the switch 61 can be
documented by a regular or continuous writing of this evaluation
result into the non-volatile memory 75, for example for the case of
a disturbance or of an accident.
[0053] FIG. 5 shows an embodiment of a securing and monitoring
system for a switch 61 of an industrial plant modified with respect
to FIG. 4. This securing and monitoring system also includes a
padlock 63 having an RFID transponder 48, as explained in
connection with FIGS. 1 to 3. The hoop 13 of the padlock 63 is hung
into a blocking device 65 of the switch 61. Unlike the embodiment
in accordance with FIG. 4, a stationary RFID reading device is
arranged at the switch 61 or in the vicinity of the switch 61, i.e.
the RFID reading device 79 is permanently fastened to the switch 61
or in the vicinity of the switch 61 for its operation.
[0054] An interrogation signal which is converted in the RFID
transponder 48 of the padlock 63 into an identification signal can
be automatically triggered by means of the stationary RFID reading
device 79. This identification signal characteristic for the RFID
transponder 48 and thus for the padlock 63 can be received and
decoded by the stationary RFID reading device 79. The piece of
identification information acquired from this is then stored in a
non-volatile memory 75 of the stationary RFID reading device 79,
preferably together with a piece of time information. The securing
state of the switch 61 is thus monitored so that a check can be
made by reading out the non-volatile memory 75 which padlock has
been arranged at the switch 61 or was arranged thereat at an
earlier time.
[0055] It must still be noted with respect to the explained
embodiments that, instead of the shown lock housing 21 and inner
housing 23 (FIGS. 1 and 2), for example a multipart outer lock
housing of plastic can be provided, in particular in the manner of
an open housing having an associated cover, or in the manner of a
two-part lock housing having a central dividing plane as known from
the initially named document U.S. Pat. No. 5,755,121. In the case
of such a multipart lock housing of plastic, an inner housing can
optionally additionally be provided.
[0056] Instead of a padlock having a U-shaped hoop, a padlock can,
for example, also be used having a curved rotary hoop.
REFERENCE NUMERAL LIST
[0057] 11 lock body [0058] 13 hoop [0059] 15 locking recess [0060]
17 ring groove [0061] 19 abutment head [0062] 21 lock housing
[0063] 23 housing part [0064] 25 securing screw [0065] 27 lock
cylinder [0066] 29 locking mechanism [0067] 31 cylinder core [0068]
33 keyway [0069] 35 cylinder housing [0070] 37 driver projection
[0071] 39 rotational bolt [0072] 41 blocking ball [0073] 43
engagement projection [0074] 45 receiving recess [0075] 47 locking
section [0076] 48 RFID transponder [0077] 49 nut [0078] 51 hoop
receiving passage [0079] 53 cover [0080] 55 key [0081] 57 recess
for the RFID transponder [0082] 59 recess for the lock cylinder
[0083] 61 switch [0084] 63 padlock [0085] 65 blocking device [0086]
67 reference RFID transponder [0087] 69 mobile RFID reading device
[0088] 71 transmission and reception antenna [0089] 73 control and
evaluation circuit [0090] 75 non-volatile memory [0091] 77 energy
supply device [0092] 79 stationary RFID reading device [0093] A
axis of rotation
* * * * *