U.S. patent number 3,911,534 [Application Number 05/519,270] was granted by the patent office on 1975-10-14 for anti-theft fastening device.
This patent grant is currently assigned to I. D. Engineering, Inc.. Invention is credited to Henry J. Martens, Jan Vandebult.
United States Patent |
3,911,534 |
Martens , et al. |
October 14, 1975 |
Anti-theft fastening device
Abstract
A fastening device for securing articles together, the device
including releasably connected male and female components. The male
component comprises a pin and the female component comprises a
retaining insert positioned in a housing for releasably clamping
the pin. When joined, the pin can not be separated from the
retainer except by a special tool. The insert is of magnetic
material, and an actuating tool including an electromagnet is
employed to actuate the insert to permit removal of the pin. The
housed insert is attached to a tag, with the tag being attached to
the article which is to be sold. The tag houses an electrical
circuit which activates an alarm if the tag is not properly removed
at the checkout point by means of the special tool.
Inventors: |
Martens; Henry J. (Lynnfield,
MA), Vandebult; Jan (Topsfield, MA) |
Assignee: |
I. D. Engineering, Inc.
(Peabody, MA)
|
Family
ID: |
24067573 |
Appl.
No.: |
05/519,270 |
Filed: |
October 30, 1974 |
Current U.S.
Class: |
70/57.1;
24/704.2; 70/276; 24/704.1; 24/706.8; 70/282; 340/572.8 |
Current CPC
Class: |
E05B
73/0052 (20130101); E05B 73/0017 (20130101); E05B
73/00 (20130101); Y10T 24/50 (20150115); Y10T
24/505 (20150115); Y10T 70/5004 (20150401); Y10T
24/4614 (20150115); Y10T 70/7057 (20150401); Y10T
70/7124 (20150401) |
Current International
Class: |
E05B
73/00 (20060101); E05B 47/00 (20060101); A44B
009/00 (); G08B 013/00 (); G08B 021/00 () |
Field of
Search: |
;340/258D,280 ;70/276
;292/252 ;24/15R,155BR,21B,252DP,49CP |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Magnetic Lock Foils Snoopers" Popular Science, Feb. 1951, pp. 219
& 220..
|
Primary Examiner: Griffin; Donald A.
Attorney, Agent or Firm: Beall & Jeffery
Claims
I claim:
1. The combination of a fastening device and a detaching tool for
releasing the same comprising:
a. a generally cylindrical non-metallic housing closed at one end
and formed with a central opening and a relatively enlarged recess
at the open end of said housing;
b. a ring mounted in said recess in said housing, said ring being
formed with a downwardly and inwardly tapered inner surface;
c. an insert formed of magnetic material loosely received within
said housing and extending upwardly substantially into said central
opening, said insert being formed with a conical lower end adapted
to mate with said tapered surface of said ring, an axial bore, and
at least one transverse opening formed in said conical end of
relatively greater dimension than said axial opening;
d. a pin extending upwardly through said axial bore of said
insert;
e. retaining ball means disposed within said transverse opening of
said insert;
f. spring means for resiliently biasing said insert toward the open
end of said housing thereby adapting said retaining ball means to
tightly frictionally engage said pin and retain the same in said
insert, and
g. a detaching tool for releasing said retaining ball means and
freeing said pin, said tool including electromagnetic means and
circuit means for energizing said electromagnetic means, said
detaching tool when positioned adjacent the closed end of said
housing and when said electromagnetic means is energized
functioning to retract said insert against the bias of said spring
means thereby permitting movement of said retaining ball means away
from said pin to permit removal of said pin.
2. A fastening device comprising:
a. a generally cylindrical non-metallic housing closed at one end
and formed with a central opening and a relatively enlarged recess
at the open end of said housing;
b. a ring mounted in said recess in said housing, said ring being
formed with a downwardly and inwardly tapered inner surface;
c. an insert formed of magnetic material loosely received within
said housing and extending upwardly substantially into said central
opening, said insert being formed with a conical lower end adapted
to mate with said tapered surface of said ring, an axial bore, and
at least one transverse opening formed in said conical end;
d. a pin extending upwardly through said axial bore of said
insert;
e. retaining ball means disposed within said transverse opening of
said insert, and
f. spring means for resiliently biasing said insert toward the open
end of said housing thereby adapting said retaining ball means to
tightly frictionally engage said pin and retain the same in said
insert.
3. The fastening device of claim 2 wherein said retaining ball
means comprises a pair of balls positioned in said transverse
opening formed in said insert.
4. The fastening device of claim 2 wherein the open end of said
housing is formed with a laterally outwardly extending peripheral
flange.
5. A fastening device comprising:
a. a generally cylindrical non-metallic housing closed at one end
and formed with a central opening and a relatively enlarged recess
at the open end of said housing;
b. a ring mounted in said recess in said housing, said ring being
formed with a downwardly and inwardly tapered inner surface;
c. an insert formed of magnetic material loosely received within
said housing and extending upwardly substantially into said central
opening, said insert being formed with an axial bore, and at least
one transverse opening formed in the lower end of said insert;
d. a pin extending upwardly through said axial bore of said
insert;
e. retaining ball means disposed within said transverse opening of
said insert, and
f. spring means for resiliently biasing said insert toward the open
end of said housing thereby adapting said ball means to engage said
ring and tightly frictionally engage said pin and retain the same
in said insert.
Description
BACKGROUND OF THE INVENTION
The present invention relates as indicated to a fastening device
and a tool for releasing the same, and relates more particularly to
a fastening device which can be attached to an article or articles
in such a manner that the device can be separated only by the use
of a special tool located for example, at a checkout point in a
department store or the like. In accordance with the present
invention, the fastening device is secured to an identification tag
with the assembly in turn being temporarily secured to articles
prior to the authorized handling and sale of such articles, at
which time the identification tag and device can be removed from
the article. The invention is thus highly useful for purposes of
anti-theft detection in department stores and the like where the
identification tag must be removed from the article purchased
during the check-out process. If a person attemps to
surreptitiously remove the article from the store without
purchasing the same, the identification tag which remains attached
to the article contains electric circuitry which triggers an alarm
system at an exit point or points in the store.
The fastening device constructed in accordance with the present
invention comprises an improvement over the fastening devise
disclosed and claimed in pending App. Ser. No. 307,366, filed Nov.
17, 1972 in the name of Martin A. J. Martens and entitled
"Fastening Clip," now U.S. Pat. No. 3,858,280 granted Jan. 7, 1975.
In accordance with such earlier application, the fastening device
likewise comprised a male component in the form of a pin and a
female component in the form of a retainer resiliently mounted in a
housing. The coupling of the pin to the retainer, with the pin
extending through the article to be sold, precluded disengagement
of the pin from the retainer except by a special tool. The
construction of the retainer and housing was such as to permit
activation of the retainer and consequent release of the pin either
mechanically or magnetically. When mechanically activated, a
detaching tool is inserted through a top opening in the housing in
which the retainer is mounted for withdrawing the retainer to
permit release of the pin. When magnetically activated, an
electromagnet is positioned adjacent the same open end of the
housing and the retainer, formed of magnetic material, is drawn
toward the electromagnet thereby freeing the pin for removal from
the retainer.
Although the fastening clip and described forms of activation in
the noted application proved generally satisfactory, certain
disadvantages did exist. In the form requiring mechanical
activation, the use of the special tool is relatively
time-consuming and required significant manual dexterity. In
addition, the open end of the housing, required for mechanical
activation, did not absolutely preclude tampering with the device
in an effort to surreptitiously remove the device prior to checkout
of the article.
SUMMARY OF THE INVENTION
A primary object of the present invention is to provide a fastening
device which can be quickly and easily secured to the article or
articles to be temporarily fastened, while at the same time
providing a locking arrangement which positively prevents
separation of the fastener components without a special tool. In
accordance with the invention, any attempted removal or separation
of the fastener components serves to increase the resistance to
such separation. The female section of the fastener is constructed
so as to prevent separation of the fastener components except by a
specially designed tool.
A further, more specific object of the invention is to provide a
fastening device in the form of a lock which is positioned in one
half of a tag assembly, with the securing of the other half of the
tag assembly preventing removal of the fastening device from the
tag. The device is mounted in the tag in such a manner as to permit
rotation thereof thereby preventing the pin from being unscrewed
from the lock prior to authorized detaching of the pin from the
lock. The lock housing is closed in the exteriorly exposed regions
thereof to prevent access to the interior thereof.
Another object of the invention is to provide a lock and tag
assembly which are of extremely rugged construction, thereby
permitting repeated reuse of the lock and tag.
A still further object of the invention is the provision of a novel
electromagnetic detaching tool for conditioning the lock for
removal of the pin at the checkout station. In accordance with the
invention the pin-retaining insert of the lock is formed of
magnetic material whereby positioning of the detaching tool
adjacent the exposed, closed end of the lock and actuation of the
tool releases the pin from the insert positioned interiorly of the
lock for removal of the pin. In accordance with the invention, the
insert is spring biased away from the closed end of the lock into
frictional engagement with a ring having a tapered inner surface
complemental to the tapered outer surface of the insert. When the
insert is so biased, retaining balls loosely positioned in the
insert tightly frictionally engage the surface of the pin, with the
frictional contact increasing when the pin is attempted to be
removed from the lock prior to authorized removal of the pin at the
checkout station by the detaching tool.
Yet another object of the invention is to provide such a detaching
tool the electrical circuit of which includes an overload
protection device which prevents overheating of the magnetic coil
when the actuating switch for the tool is inadvertently left closed
for longer than a predetermined time .
These and other objects of the invention will become apparent when
the following description proceeds in particular reference to the
application drawings.
BRIEF DESCRIPTION OF THE APPLICATION DRAWINGS
FIG. 1 comprises a side elevational view of the lock and tag
assembly in accordance with the invention;
FIG. 2 is an exploded, partially sectioned view of the lock
assembly and pin;
FIG. 3 is an exploded view of the tag assembly;
FIG. 4 is a circuit diagram of the tag assembly;
FIG. 5 is an exploded view of the detaching tool in accordance with
the invention, and
FIG. 6 is a circuit diagram of the detaching tool.
FIG. 7 is a modification showing the pin attached to the tag,
and
FIG. 8 is a further modification showing the pin attached to a
separate strip hinged to the tag.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now in more detail to the application drawings, wherein
like parts are indicated by like reference numerals and initially
to FIGS. 1 and 2, FIG. 1 illustrates an assembled lock and tag
assembly, with the lock assembly being generally indicated at 10
and the tag assembly generally indicated at 12. The tag assembly
comprises tag cover sections 14 and 16 which are formed with mating
peripheral and interior portions so as to permit the sections to be
rigidly secured together, with the construction of the tag sections
to be hereinafter described when particular reference is made to
FIG. 3. An antenna generally indicated at 18 is mounted between the
tag sections for triggering an alarm circuit if the tag and lock
assembly are surreptitiously removed from the premises without
authorized removal of the tag from the article to be purchased at
the checkout station, as will be hereinafter described in more
detail. The tag section 14 is formed with an opening 20 generally
aligned with the axis of the lock 10 through which the fastening
pin can extend into frictional engagement with the lock, with the
pin being shown in FIG. 1, attaching an article A, shown in dashed
line, to the device.
Referring to FIG. 2, the lock assembly 10 comprises a housing 24
which is generally hat-shaped and closed at one end. An insert 26
is mounted for longitudinal movement in central bore 28 of the
housing, and the housing is counter bored as shown at 30 to receive
a retaining ring 32. The ring 32 and the bore 30 are dimensioned so
as to permit press fitting of the ring into the bore for permanent
retention in the housing. The housing is preferably made of
"Lexan," a commercially available product sold by General Electric,
although it will be understood that other suitable plastic
materials could likewise be employed. The ring 32 is perferably
formed of steel, as is the insert 26.
The insert 26 includes a relatively reduced diameter upper section
34 the bottom of which is defined by a shoulder 36 against which
the bottom of a compression spring 38 engages, with the top of the
spring engaging a flat annular surface 40 formed adjacent the
closed end of the housing. The lower portion of the insert is
tapered and formed with a transverse opening 42 within which
retaining balls 44 and 46 are loosely mounted. A central bore 48 is
formed in the insert of sufficient diameter to receive the shank
portion 50 of a pin generally indicated at 52. The pin 52 further
includes a head portion 54, with the shaft being secured to the
head by soldering as shown in 56, or equivalent securing methods,
in addition to the regular staking method. Such method of securing
the shank to the head greatly strengthens the pin and permits
repeated use of the same without fear of weakening or breaking.
The ring 32 is formed with a conically tapered inner surface 58
which complements the tapered lower portion of the insert 26, with
the spring 38 biasing the insert downwardly so that the adjacent
tapered surfaces of the insert and ring are in tight frictional
contact. In such position, the retaining balls 44 and 46 are forced
by the surface of the ring 58 into the axial bore 48 of the
insert.
When the pin 52 is to be inserted into the lock assembly 10 the
shank 50 of the pin is positioned in the axial bore 48 of the
insert and the pin forced toward the closed end of the housing 24.
In the position of the retaining balls 44, 46 shown in FIG. 2, the
shaft 50 is precluded from moving past the balls, although
continued movement of the shaft of the pin toward the closed end of
the housing forces the insert 26 upwardly against the bias of
spring 38. As the insert is raised in the housing, the retaining
balls are able to move laterally outwardly in the transverse bore
42 thereby permitting the shaft 50 to travel past the adjacent
surfaces of the retaining balls into the interior of the insert.
When the head 54 of the pin is adjacent the article to which the
tag and lock assembly is secured, the pin is released and the
spring 38 biases the insert downwardly thereby biasing the
retaining balls 44 and 46 into tight frictional engagement with the
surface of the shank portion 50 of the pin. In this manner, the pin
is rigidly secured in the lock, and any attempted removal of the
pin prior to authorized removal at the checkout station serves only
to increase the frictional resistance between the retaining balls
44 and 46 and the pin inasmuch as the attempted withdrawal of the
pin serves to force the insert 26 downwardly against the tapered
surface of the ring 32, against the inner surface of which the
retaining balls 44 and 46 engage. There is thus provided a lock and
pin assembly which is completely effective unless and until the
lock assembly is actuated as will be hereinafter described to
longitudinally upwardly move the insert 26 thereby freeing the
pressure of the retaining balls 44 and 46 on the shank 50 of the
pin. As above noted, the insert 26 is of steel, and positioning of
the detaching tool adjacent the closed end of the housing and
actuation thereof serves to withdraw the insert toward the closed
end of the housing thereby conditioning the lock assembly for
removal of the pin.
Referring now to FIG. 3, there is illustrated therein in exploded
view the components of the tag assembly 12. It will be noted that
the cover section 14 of the tag assembly is shown inverted in FIG.
3 and that when assembled the tag section will be positioned on the
tag section 16 so that the internal rib constructions are
adjacently disposed. As shown in FIG. 1, the exposed surfaces of
the tag sections 14 and 16 when the tag is assembled are smooth to
facilitate handling of the tag and to accommodate instructional or
advertising printing on the tag surfaces.
Each tag section is formed with a series of longitudinal ribs
commonly designated at 60 and transverse ribs commonly designated
at 62 which extend perpendicular thereto, with the ribs in each
section forming a grid-like internal construction. The longitudinal
and transverse ribs in each section are located so as to be aligned
when the tag section 14 is superimposed on the bottom tag section
16 prior to securing the sections together when the tag is
assembled. The ribs 60 and 62 are primarily for the purpose of
substantially strengthening the tag thereby to achieve the desired
objective of repeated use of the tag. The tag construction together
with the material employed for th etag, preferably ABS, although
other rugged plastic material of equivalent properties could also
be employed, provide a tag assembly which is virtually
indestructible and capable of repeated use without significant
deteriation. The surfaces of the ribs 60 and 62 are slightly
recessed relative to the peripheral surfaces of the cover sections,
as shown in FIG. 1, thereby to accommodate therebetween an antenna
generally indicated at 64. The antenna 64 is generally U-shaped,
including leg sections 66 and 68 and a center section 70. The
antenna is preferably formed of brass, and is approximately .002
inches in thickness. The antenna is adhesively secured to an
underlying tape member 72, a commercially purchased item from the
Minnesota Mining and Manufacturing Company and sold under the
product designation "3M270."
A projection 74 is provided on the antenna leg 68 for spacing
longitudinally on such leg a gold plated brass ribbon 76 on which
is secured a diode 78. Due to the relatively small size of the
diode, the ribbon 76 is required to span the gap between the
respective sections of the antenna leg 68 to establish electrical
contact between the diode and the antenna. A second tape strip 80
extends over the antenna leg 68 overlying the ribbon and diode to
further protect the same and to prevent premature failure of these
members in the antenna circuit. To protect the diode on the bottom
side thereof, a rubber insert 82 is positioned below the diode and
supporting ribbon between the same and the tag cover section
16.
The assembly of the tag 12 should be apparent from the above
description. After positioning the antenna and diode on the tag
section 16 by the tape members as above described, the tag sections
14 and 16 are aligned as shown in FIG. 1, and ultrasonically welded
whereby the tag sections are rigidly secured together. The
positioning of the diode relative to the antenna leg 68, at the
location of the projection 64, is relatively important so as to
correctly tune the antenna to a certain frequency. The transmittal
signal from the antenna section 68 is preferably double the signal
received by the antenna section 66, and the diode must be fairly
precisely positioned along the antenna leg 68 to obtain this
doubling frequency characteristic.
As shown in FIGS. 1 and 3, the cover section 16 of the tag is
formed with a tubular extension 84 at one end thereof for receiving
the lock assembly 10, and the other cover section 14 is formed with
a semicircular projection 85 at its forward end which overlays and
closes the tubular extension when the tag sections are superimposed
and secured. The projection 85 is formed with opening 20 for
receiving the shank 50 of pin 52.
The tubular extension 84 is recessed at 86 (FIG. 1) to receive the
peripheral bottom flange 87 (FIG. 2) formed on the lock housing 24.
As seen in FIG. 2, the housing 24 is downwardly and outwardly
tapered toward flange 87, which construction permits the lock
housing to be rotated in the tubular extension 84 but prevents the
lock from being withdrawn from the tag section 16 due to the flange
87. The lock 10 is dropped in the tubular extension 84 before the
tag section 14 is secured to the lower tag section 16.
The ability of the lock 10 to rotate in the tag assembly as
described, and the rounded, closed end of the lock, are of
significant importance inasmuch as relative rotation of the pin and
lock is inhibited when assembled thereby making difficult the
removal of the pin from the lock prior to authorized removal at the
checkout station. The head 54 of the pin is preferably positioned
closely adjacent the tag cover 16 and of course the pin penetrates
through the article to which the tag assembly is temporarily
secured.
The circuit diagram for the tag assembly 12 is shown in FIG. 4,
with the antenna legs 66 and 68 being schematically represented,
and diode 78 and ribbon 76 extending between the antenna legs. As
above noted, the receiving frequency at antenna leg 66, due to
diode 78, is preferably doubled so that the transmitting frequency
can be precisely detected at a chosen site or sites in the store at
which detection equipment is positioned. In this regard, reference
is made to my earlier U.S. Pat. No. 3,711,848 which specifically
describes such detecting equipment, which is normally positioned at
one or more exits from the store for the purpose of detecting
articles attempted to be removed from the store with the tag still
on the article. As described in my earlier patent, a transmitter
unit is preferably positioned at one side of the exit and
constantly transmits a signal at a predetermined frequency. When an
article bearing a tag is attempted to be passed through the exit
without authorization, the signal is picked up and doubled as
described, with the higher signal being picked up by a receiver
unit likewise positioned adjacent the exit for actuating an alarm
circuit, with the alarm comprising a flashing light, bell or other
audible or visual alarm, or combinations of these. Although the
operating frequencies are not critical, preferably high frequency
ranges are employed in order to preclude false actuation of the
system by unprotected articles passing through the checkpoints,
with the typical operating frequency at the lower range being 912
megacycles and the doubled frequency being 1,824 megacycles.
Referring now to FIG. 5, which comprises an exploded view of the
detaching tool constructed in accordance with the invention, the
detaching tool generally indicated at 90 and includes a bottom
plate 92 and a cover 94. Mounted in the cover 94 is an indicator
light L.sub.1 and a pushbottom switch S.sub.1, with the latter
being partially exposed at the exterior of the cover through
opening 100 formed in a side wall of the cover. As illustrated, the
indicator light L.sub.1 is exposed through an opening formed in the
top of the cover.
Mounted on bottom plate 92 is a magnetic coil C.sub.1 formed of
copper windings (not shown) and generally doughnut shaped in cross
section. An iron core C.sub.2 is mounted for longitudinal movement
within the center opening of the coil C.sub.1, with the core
C.sub.2 being somewhat greater in diameter than an opening 102
formed generally centrally in the top wall of the cover 94. The
opening 102 is for the purpose of conveniently aligning the iron
core with the lock when it is desired to remove the pin from the
lock at the checkout station. It will be noted that the coil
C.sub.1 is relatively large thereby providing a powerful magnetic
force on the core C.sub.2 for retracting the insert 26 upwardly in
the housing 24 of the lock when the lock is positioned adjacent the
detaching tool. As previously described, the retraction of the
insert 26 permits transverse outward movement of the retaining
balls 44 and 46 thereby permitting removal of the pin 52 from the
lock at the checkout station.
Also mounted on the bottom plate 92 are relays R.sub.1 and R.sub.2
which are carried on bracket 104 which is secured to the bottom
plate by any suitable means. A rectifier plate 106 carrying
rectifiers D.sub.1, D.sub.2, D.sub.3, and D.sub.4 is also mounted
on the bottom plate 92 adjacent the relays R.sub.1 and R.sub.2.
Referring to FIG. 6, the circuit diagram for the detaching tool,
the cover 94 and bottom plate 92 are shown in dash lines in the
circuit diagram, and it will be noted that plug connectors commonly
designated at PC are provided on the cover and bottom plate for
plugging in the cover to the plate. Such method of assembly permits
the cover to be removed quickly and easily from the bottom plate
for repair or replacement of the circuit parts. A power plug 110 is
provided, shown schematically at the left of the circuit diagram,
connected to a suitable source of alternating current such as a
wall outlet or the like.
The components previously described in connection with FIG. 5 are
illustrated in the schematic diagram, and the operation of the
detaching tool should be apparent from the diagram. When the cover
is plugged in the bottom plate, the closing of switch S.sub.1
activates coil C.sub.1 through the diodes D.sub.1, D.sub.2, D.sub.3
and D.sub.4 thereby energizing the iron core C.sub.2. When the
housing of the lock is disposed adjacent the opening 102 in the
cover 94 of the detaching tool, the insert is retracted as above
described thereby conditioning the tool for removal of the pin. The
indicator light L.sub.1 forms part of the circuit and is actuated
when the switch S.sub.1 is closed. A fuse F.sub.1 is also included
in the switch circuit. The circuit is also grounded as indicated at
G.
An important part of the detaching tool comprises an overload
protection feature provided by relays R.sub.1 and R.sub.2. When
pushbutton switch S.sub.1 is kept in an "on" position for longer
than a predetermined time period, for example 60 seconds, relay
R.sub.1, which is a delay relay, will be activated, with relay
R.sub.1 in turn activating relay R.sub.2. Relay R.sub.2, which is
normally closed, is opened when activated thereby shutting off
power to the coil and preventing overheating of the coil. The
overload protection thus insures long life of the coil and thus the
detaching tool.
FIGS. 7 and 8 illustrate modifications in which the pin is
permanently attached to the tag. Referring to FIG. 7, which is
particularly suited for applying the tag to hardware items, tools,
sporting goods and the like, the pin 52 is secured to one end of a
chain 120, by soldering, for example. The other end of the chain
120 is attached to a rivet 122 secured to the tag cover section 14.
In use, the chain 120 is looped around the article to which the tag
is to be attached, with the pin extending into opening 120 as
previously described to lock the pin, and thus the article, to the
tag. The modification has the further advantage of the pin being
permanently attached to the tag to facilitate application of the
pin to the lock.
Referring to FIG. 8, in this form the pin 52 is permanently
attached to a strip 124, preferably of plastic, one end 126 of
which is secured to the tag cover section 14 by riveting or
ultrasonic welding so as to rigidly secure the connection. The main
body portion of the tag is of less thickness than the end portion
126, and the plastic material and method of attachment to the tag
is such that the strip is normally biased away from the tag as
shown in FIG. 8. This modification is particularly useful for
application of the tag and lock to soft goods such as clothing,
with the pin 52 being mounted on the strip 124 so as to be aligned
with the lock when the pin is moved toward the lock. This
modification also has the advantage, as in FIG. 7 of the pin being
permanently connected to the tag to facilitate handling and
application of the tag assembly to the goods.
It will thus be seen that the objects of the invention have been
accomplished. The tag assembly which mounts the lock and houses the
antenna circuit is constructed of a rugged plastic material which
insures long life of the tag without significant deterioration. The
antenna is sealed within the tag, and the lock is mounted at one
end of the tag assembly in such a manner as to preclude removal
from the tag. The tag and lock are therefore virtually fool-proof
and permit alarm detection at an exit or exits from the store when
the tag and lock are attempted to be removed with an article
without authorization. The pin can be detached from the lock simply
and quickly by the detaching tool thereby permitting subsequent
reassembly of the pin with the lock on other articles to be
protected. The detaching tool is simple in construction and
provides a strong magnetic force for actuating the lock at the
checkout station, with the tool being simply positioned adjacent
the lock and the actuating switch depressed to close the circuit
through the magnetic coil. The detaching tool includes and overload
protection feature which precludes actuation of the magnetic coil
beyond a predetermined time period thereby preventing overheating
of the coil and premature failure of the detaching tool.
* * * * *