EP0142748A1

EP0142748A1 - A lock for securing a mark especially onto a textile article

Info

Publication number: EP0142748A1
Application number: EP84113110A
Authority: EP
Inventors: Herman Braun
Original assignee: ASX 4280 APS; Antonson Security Denmark AS
Current assignee: Actron Entwicklungs AG
Priority date: 1983-11-04
Filing date: 1984-10-31
Publication date: 1985-05-29
Also published as: EP0142748B1; DE3472993D1; DK149540B; ATE36025T1; DK506483A; DK506483D0; DK149540C

Abstract

The lock is preferably to be used for burglar alarms for marking articles for sale, and it comprises two members automatically interengaging when the first member (1) is inserted in a cavity (7) in the second member (5, 6), a loose third member (8) being positioned in said cavity. The locking effect is provided by the loose third member (8) comprising one, optionally more inclined surfaces (10) capable of being tangent to and sliding along a corresponding inner wall in the cavity (7) of the second member. The cavity of the second member is pointed upwards, i.e. towards the inlet opening. A spring (11) is provided below the loose third member (8), and this spring presses as a consequence of the inclined wall (10) the third member (8) upwards and towards the first member (1).

Description

rhe present invention relates to a lock preferably Eor a burglar alarm for marking articles for sale, said lock comprising two members automatically interengaging when one member is inserted in a cavity in the other member, whereby said first member comprises a rod-shaped body, the inserting end of which is completely or partially pointed, said body engaging a third member loosely inserted in the cavity in the second member.
When ensuring articles for sale against burglary it is important that the markers are easy to mount on the articles for sale and only can be removed by an authorized person such as a shop assistant. The available markers are encumbered with the problem that the first member for instance shaped as a solid drawing pin sometimes can be pulled out of the lock merely by subjecting the head of the "drawing pin" to an upward pull.
Consequently, the object of the invention is to provide a lock which is simple and inexpensive to manufacture and which is easy to open by authorized persons by means of special apparatuses, but which is difficult to open without said special apparatuses.
According to the invention the third member is provided with one or more inner surfaces capable of being tangent to and cooperating with corresponding inner surfaces on the second member, these surfaces being inclined upwards and inwards when seen in a vertical sectional view through the lock with the inlet of the cavity facing upwards, whereby the cavity is pointed upwards towards the inlet of the cavity and whereby a spring such as a'flat spring with an upward elastic force is situated in the cavity below the loosely positioned third member.
In this manner a locking effect is obtained between the two members. When the first member is inserted in the cavity of the second member, said first member presses the third, loosely positioned member slightly aside and a short distance downwards whereafter the point of the first member passes the third member. The spring in the bottom implies that the third member does not fall into the bottom of the cavity but instead is pressed upwards towards the top of the cavity pointed upwards. If it is tried to pull out the first member again, a friction between the first member and the third member implies that said first member is pulled upwards too and thereby inwards as a consequence of the inclined surfaces. In this manner the third member fastens on additionally to the first member, and any upward pull fixes only the first member additionally. The lock can only be released by the inner loose third member being pressed downwards against the force of the spring therebelow.
The third member may advantageously be made of a magnetizable material and the second member may be made of a non-magnetizable material such as plastics. In this manner the lock can be released by positioning the marker over a suitably strong magnet attracting the third member, whereby the magnet must be so strong that it can overcome the spring force. The lock may, however, also be released in another manner. The top side of the second member may be completely or partially provided with hidden openings allowing the third member to be pressed into the cavity by means of an implement in such a manner that the first member can be removed from the lock.
According to the invention the loosely positioned third member may be shaped as a disc with an inclined upward projection, one surface of which forms one of the cooperating surfaces. As a result, a simple embodiment is obtained suited for the manufacture of a magnetizable steel alloy. The inclined upward projection on the third member may be provided with a bending forming a barb, and the rim of this barb may towards the first member be shaped as part of a circular arc with a radius fitting the radius of the rod-shaped body of the first member. The rod-shaped body of the first member may advantageously comprise a notch forming a cut cooperating with the rim shaped as a circular arc of the projection. In this manner an efficient engagement of the first and the third member is ensured.
The second member may comprise two ultrasonically welded plastic portions, viz. an upper portion and a lower portion, and the lower portion may be cast with an upwardly inclined plastic flap forming the spring supporting the loosely positioned third member, whereby a very simple and inexpensive manufacture is rendered possible.
_IAccording to a second embodiment, the third member is shaped as two half truncated or pyramidal cones comprising axial bores in the opposing inner sides so that the rod-shaped body of the first member can be received between the two halves, and whereby the halves are provided on the inner sides of the bores with jaws capable of gripping about the first member. At the same time the inclined outer surfaces of the third member may slide against cooperating, touching surfaces on the inner side of the second member.
The invention will be described below with reference to the accompanying drawing, in which

Figure 1 is a sectional view through an embodiment of a lock according to the invention,
Figure 2 is a sectional view corresponding to Figure 1, where the lock is opened,
Figure 3 illustrates a lock with openings for an implement for releasing the lock,
Figure 4 is a sectional view through a second embodiment of a lock according to the invention, and
Figure 5 illustrates the V-shaped resilient member pressing a disc with a locking pin upwards.

Figure 1 illustrates a lock according to the invention. The lock comprises a first member 1 in the form of a steel pin with a plastic head. The pin is pointed in the inlet end and comprises a turned, narrowed portion 2. The lock furthermore comprises a second member 5, 6 inserted in a marker for a burglar alarm on an article for sale. The marker is preferably made of plastics in two portions 3, 4 with ₃ cavity receiving the second member 5, 6. When the second member has been inserted, the two portions 3, 4 of the marker are assembled, for instance by nlstrasonic welding, into an inseparable unit. _Al-ternatively, the marker may be cast or pressed about the second member of the lock. The second member of the lock comprises two portions 5, 6 preferably made of plastics. These two portions are also assembled by ultrasonic welding and surround a cavity 7. A movable member 8 is positioned in this cavity. This movable member is a disc 9 with a pressed projection or flap 10 bent at its upper end to form a barb which can be directed towards the first member.
In the preferred embodiment the disc 9 is made of a hardened and magnetizable steel. The lower portion 6 of the second member is shaped during the casting with a pressed flap 11 forming a spring in the bottom of the lock. The spring presses the movable disc 9 upwards. The cavity 7 is greatest in the lower portion 6 of the second member, where both the loose, movable disc 9 and the spring 11 can be positioned. The cavity is so high that the disc 9 with the projection 10 can be pressed a substantial distance downwards through a suitably strong downward influence, said distance almost corresponding to half the length of the upward projection 10. The bottom of the cavity is insignificantly greater than the disc. As illustrated in Figure 2, a displacement of the third member along the sliding surface on the projection 10 implies that the disc is carried into the bottom of the lock. The side surface 12 of the lower portion of the second member facing the cavity .s in the illustrated embodiment provided with the same inclination as the upward projection of the :hird member. To the right in Figure 1, the disc 9 Ls of such an extent that it almost touches the above side surface. When the third member is pressed downwards, e.g. when subjected to a magnet, the disc is displaced a short distance to the left and released from the first member, cf. Figure 2. The uppermost portion of the cavity 7 can receive the upward projection 8 of the third member and comprises an inclined, planar or conical wall so that the cavity 7 is pointed upwards. The projection 10 may comprise a planar side or a curved surface such as for instance a circular, cylindrical or conical surface, and this surface is tangent to the inner wall of the upper portion of the second member. This inner wall may be an inclined planar wall, but it may also be provided with a curvature. It is essential that the curvature allows the two surfaces to slide against one another in order to release the first member.
When the marker is to be secured to an article, the steel pin 1 of the first member is stuck through the article, e.g. in a sewing or a seam in a garment and pressed into an opening in the uppermost portion of the second member and further into the cavity downwards and past the projection 10. As a result, the disc 9 with the projection 10 is pressed a short distance downwards against the force of the spring 11. The projection 10 fastens fixedly to the pin 1 of the first member, the pin thereby being retained. Attempts of pulling out the first member 1 imply that the pin transfers the movement to the projection 10 and the disc 9. The inclined surface of the projection 10 and the corresponding surface on the upper portion 5 of the second member now imply that the projection is pressed even more firmly onto the pin _Df the first member and the cavity restricts the movement of the disc 9 and the projection upwards and thereby the movement of the first member. Opposite the inclined surface in the upper portion of the second member, the second member may be reinforced by an extra hard wall 15, e.g. of light metal. In this manner this wall is prevented from giving in to the pressure that it can be subjected to when it is tried to wriggle the first member so as to tear it off. The pin or the rod 1 of the first member may be a completely smooth rod, but it is preferably provided with circumferential grooves or narrowings engaging the projection 10 of the third member.
The lock is released by the third member, i.e. the disc 9 with the projection 10, being pressed or pulled downwards against the force of the spring 11. This procedure can be carried out by positioning the marker over a magnet, the magnetic field of which pulls down the steel disc 9. One or optionally several compound cobalt magnets may be used as magnet. As an alternative, the lock may be opened by inserting a needle or a U-shaped hoop downwards into one or two openings provided for this purpose in the upper portions 3, 5 in such a manner that the disc 9 can be pressed downwards as indicated in Figure 3. Such openings should be shaped as discrete as possible and for instance be covered by a mark as an insurance against burglary.
Figure 4 illustrates a second embodiment according to the invention. The same reference numerals have been used in the previous Figures. The movable member is shaped as a two-piece or truncated cone 8a, 8b, and on the inner side of each half opposing jaws 13 are provided. The Figure illustrates three pairs of jaws, but this number may, of course, vary. The inclined surface of the cone may slide on corresponding inclined surfaces 14 on the inner side of the cavity in the upper portion 5 of the second member. The cone is supported by two springs 11, lla in the form of cast upward plastic "flaps". One of the springs lla is fork-shaped and positioned symmetrically on each side about the spring 11. Instead of the cast plastic flaps, a helical spring may be used. The locking effect corresponds completely to the effect described in the first example. When the pin 1 is pulled out, the two cone halves follow said pin a short distance and fasten additionally thereon and thereby retain the pin. The cone angle may be varied in response to the materials used.
According to a particularly advantageous embodiment, the resilient flap 11 has been replaced by a substantially U-shaped tongue 19 communicating with the member 6 in two points 17. This tongue presses the disc 9 with the projection 10 upwards in the same manner as the flap 11. As a consequence of the broader support along the rectilinear rim 20 of the U-shaped tongue, the disc 9 cannot tilt transversely to the longitudinal axis of the U. Furthermore, the U-shaped tongue cannot be hit and damaged by a steel pin 1.

Claims

1. A lock preferably for a burglar alarm for marking articles for sale, said lock comprising two members automatically interengaging when one member (1) is inserted in a cavity (7) in the other member (5, 6) whereby said first member (1) comprises a rod-shaped body, the inserting end of which is completely or partially pointed, said rod-shaped body engaging a third member (8) loosely inserted in the cavity (7) in the second member, whereby a spring with an upward elastic force is situated in the cavity below the loosely inserted third member, and whereby the inner sides of the cavity incline towards the inlet of the cavity (7), characterised by the third loosely inserted member (8) being provided with an oblique upward projection (10) partly capable of being tangent to and cooperating with corresponding inner surfaces on the second member (5, 6), and partly being capable of engaging the rod-shaped body so as to be pressed against said body in case the latter is subjected to a pull.

2. A lock as claimed in claim 1, characterised by the third member (8) being of a magnetizable material and the second member (5, 6) being of a non-magnetizable material such as plastics.

3. A lock as claimed in claim 1, characterised by the top side (5) of the second member being provided with openings allowing the third member (8) to be pressed into the cavity (7) by means of an implement in such a manner that the first member (1) can be removed from the lock.

4. A lock as claimed in claim 1, characterised by the inner side of the cavity (7) in the second member (5) being reinforced opposite the inclined surface by means of a hard material such as for instance a brass plate (15).

5. A lock as claimed in claim 1, characterised by the third loosely positioned member (8) being shaped as a disc with an inclined upward projection (10) pressed up from the disc.

6. A lock as claimed in claim 5, characterised by the projection (10) being provided at the top with a bending forming a barb (16), and by the rim of this barb towards the first member (1) being shaped as part of a circular arc with a radius fitting the radius of the rod-shaped body of the first member.

7. A lock as claimed in claim 6, characterised by the rod-shaped body of the first member comprising a notch (2) forming a cut cooperating with the rim shaped as a circular arc of the projection (10).

8. A lock as claimed in claim 1, characterised by the second member comprising two ultrasonically welded plastic portions, viz. an upper portion (5) and a lower portion (6), and by the lower portion being cast with an upwardly inclined plastic flap forming the spring (11) supporting the loosely positioned third member (8).

9. A lock as claimed in claim 8, characterised by the flap being substantially U-shaped (Figure 5).

10. A lock as claimed in claim 1, characterised by the third member being shaped as two half truncated or pyramidal cones (8a, 8b) comprising axial bores in the opposing inner sides so that the rod-shaped body (1) of the first member can be received between the two halves (8a, 8b), and whereby the halves are provided on the inner sides of the bores with jaws (13) capable of gripping about the first member (1).