Attaching Device

The invention relates to attachment devices of the kind disclosed in U.S. Pat. Nos. 3,402,435; 3,462,802; 3,466,077; 3,516,124; 3,558,963, 3,712,655; 3,717,369; and 3,830,583; and U.S. Pat. No. Des. 214,122.

Such devices have filamentary members that are connected to pronged sockets. Each filament terminates in a head that is insertable into the associated socket cavity where it is held in position by the prongs. The devices are useful for attaching tickets and price tags to articles of merchandise. In that usage the head is passed through one or more tickets, through or about an article and finally into the socket.

The design of the socket is intended to prevent, or at least hinder the unauthorized removal of the head after it has been locked in position. Otherwise the attachment may become accidentally separated from its associated article, and the pricing ticket lost; or the head may be deliberately removed from the socket to allow "ticket switching" in which a ticket with a low price is applied to a more expensive article.

Notwithstanding various protective measures that have been taken, the prior art designs have not been successful in preventing either the accidental separation of a head from its socket or the deliberate separation of the head from the socket to permit ticket switching.

Accordingly, it is an object of the invention to enhance the security with which the head of a filamentary attaching device is locked in place in its socket. A related object is to achieve enhanced security against deliberate separation without increasing the likelihood of accidental separation of the head from the socket.

In accomplishing the foregoing and related objects, the invention provides a modification of the head so that it fills the socket cavity, except for the region of the prongs.

In accordance with one aspect of the invention undesired filling in the region of the prongs is avoided by providing a cylindrical neck near the tip of the head and coupling the neck to a truncated cone.

In accordance with another aspect of the invention a major portion of the head has a configuration similar to that of the socket, while the remainder of the head is dissimilar from the socket.

In accordance with a further aspect of the invention there is maximum clearance between the cavity and the head at an intermediate position of the prongs that form a part of the socket cavity.

In accordance with still further aspects of the invention the contour and the slope of its surface with respect to the cavity are proportioned to assure that the cavity is sufficiently filled to forestall release of the head by distortion of the socket and at the same time, prevent the kind of over-filling of the cavity that could keep the prongs from seating properly against the head.

According to yet another aspect of the invention the head of the filamentary member that is connected to the socket cavity is provided with a stop for preventing the head from being drawn through the socket. In addition the socket is provided with a shield, such as a cylindrical sleeve for preventing pressure exerted against the socket from distorting the prongs.

According to still another aspect of the invention the head is provided with one or more appendages that grip the prongs after the head is inserted into the socket in order to lock the prongs in position. This is desirably accomplished by the addition of single appendages at the tip of the prongs in order to engage an outside surface of the prongs at one or more positions when the head is inserted into the socket.

Other aspects of the invention will become apparent after consideration of several illustrative embodiments, taken in conjunction with the drawings in which:

FIG. 1 is a side view of an attaching device in accordance with the invention;

FIG. 2 is a sectional view of the device of FIG. 1 taken along the line 2--2;

FIG. 3 is a sectional view of the device of FIG. 1 taken along the line 3--3;

FIG. 4 is a sectional view of the attaching device of FIG. 1 with its head locked in position;

FIG. 5 is a sectional view of an alternative attaching device embodiment with its head locked in position;

FIG. 6A is a sectional view of a socket and associated head of a prior art type of attaching device;

FIG. 6B is a view of the device of FIG. 6A when subjected to distortion;

FIG. 7A is a sectional view of a socket and associated head of another prior art type of attaching device;

FIG. 7B is a view of the device of FIG. 7A showing prong distortion when the head is inserted into the socket;

FIG. 8A is a sectional view of a further attaching device in accordance with the invention with its head locked in position;

FIG. 8B is a perspective view of the head of the device shown in FIG. 8A; and

FIG. 8C is an end view of the socket showing its prongs locked in position by an inserted head.

As shown in the drawings, an attaching device in accordance with the invention is formed by a filamentary member or strap 10, a socket 11 and a head 15. The device is preferably made by molding a plastic material, such as nylon, as shown in certain of the reference patents. After molding, the filamentary member is desirably stretched to strengthen it.

The socket 11 includes a base member 11a with a desirably round opening, in a top surface 11g, forming the mouth or entrance of a cavity 11b. The cavity is completed by a plurality of resilient or snappable prongs 11c which define an opening 11f at their free ends 11d. Desirably included in the socket 11 is a protective shell 11e that extends outwardly from the base member 11a to prevent tampering with the prongs 11c.

The head 15 illustratively includes a tip 15a that penetrates the cavity 11b and spreads the prongs 11c until they become seated as shown in FIG. 4.

When the tip 15a passes beyond the prongs they snap into place behind the tip 15a to prevent its withdrawal.

Preferably the maximum width of the head is less than that of the cavity 11b and greater than the opening 11f at the ends of the prongs.

To the rear of the tip 15a there is advantageously a neck 15b (preferably cylindrical) and a tapered portion 15c, preferably a truncated cone, which is coupled to a cavity filling or base member 15d, which is preferably cylindrical.

The cavity filling member 15d is constructed so that the overall clearance between its outer surface and the interior of the cavity 11b is less than 10 mils and preferably between 1 to 9 mils. Thus where the member 15d is cylindrical and the cavity opening is round, the latter diameter should be 1 to 9 mils and less than 10 mils greater than the diameter of the cylindrical member.

In addition the length of the cavity filling member 15d should be such that at least 70% of the cavity 11b is filled when the tip 15a is positioned as shown in FIG. 4.

Above the head 15 and supported by the filamentary member 10 is a stop 16, as well as an enlarged portion 17. The stop 16 in the preferred embodiment acts to maintain the cavity filling member 15d within the base member 11a when the head 15 is in the position shown in FIG. 4. The members 16 and 17 also help one hold the filament to insert the head 15 into the socket 11.

In FIG. 5 there is a modification of the attachment device filament according to the invention. In this embodiment the stop 16 is moved rearwards and the shoulder 15e between the members 15c and 15d acts to engage the inner walls of the prongs 11c and locate the cavity filling member 15d within the cavity of the member 11a.

The invention prevents distortion of the member 11a and thus opening of the prongs 11d by keeping the clearance of the cavity filling member 15d and cavity 11b within certain precise limits. This is by contrast with the prior art devices such as shown in FIGS. 6A, 6B, 7A and 7B.

Thus in FIG. 6A, a head 25 at one end of a filamentary member 20 of a prior art attaching device is shown locked in position in a socket 21. The head is formed by a stop 26 that is joined to a tip 25a by a thin cylindrical rod 25d. It is held in position in the socket by the stop 26 and the prongs 21c that snap into place behind the tip 25a. The channel in the socket 21 is a truncated conical void 21t. When side pressure is applied, the walls of the socket become depressed as shown in FIG. 6B, allowing the tip 25a to be easily withdrawn.

In another prior art device shown in FIG. 7A a head 35 at one end of a filamentary member 30 has a base member 35d that is connected to a tip 35a by a tapered member 35c. If the head 35 does not closely follow the configuration of the channel 31t in the socket 31, the fingers 31c cannot properly grip the head 35.

For example, as shown in FIG. 7B, where the base member 35d of the head 35 is slightly longer than the upper part of the channel 31t the fingers 31c are distended, permitting easy removal of the head 35. Alternatively for example, if the conical portion 35c of the head 35 is larger than the lower part of the channel 31t, there is continuous undesirable stress on the fingers which can produce a fatigue effect that permits easy withdrawal of the head 35.

The difficulties with the prior art devices are overcome by the invention, which is further illustrated in FIGS. 8A through 8C. The head 45 is formed by a base 45d with a tip 45a which extends to a cylindrical neck 45b by flared member 45c. The latter has a surface curvature that has a change in slope between the neck 45b and the base 45d. As a result there is maximum clearance between the channel cavity 41t and the head 45 at an intermediate position of the prongs 41c.

The neck 45b has a diameter that is equal or slightly less than the opening at the end of the prongs. This, coupled with the intermediate void 41t between the flared member 45c and the prongs 45c, prevents undesired distention of the prongs when the head 45 is locked in position. In addition the tip 45a has locking appendages 45e which grip the outer surface 41s of the prongs 41c at one or more positions as illustrated by FIGS. 8A and 8C. At the same time the proportions of the head 45 prevent lateral compression of the socket from permitting inadvertent or unauthorized withdrawal of the head 45 from the socket 41.

In particular the outer surface of the head 45 forms an acute angle with the inner surface of the prongs 41c, and the head 45 has a contoured surface with a continuous change of slope from the neck 45b to the base 45d. The locking appendages of the tip 45a may take any convenient form for the purpose of enhancing the security against tampering afforded by the invention.

The continuous change in slope is characterized by going from a minimum to a maximum and then returning to a minimum over the region of the prongs 41c. It is to be noted that in the case of the attaching device shown the base 45d has a length which exceeds the combined lengths of the neck 45b and the flared member 45c. This enhances the security against tampering afforded by the invention, but it is to be noted, for example in FIG. 5, that the base, e.g. 15d may have a length which is less than the combined lengths of the neck and the conical portion 15c.

The foregoing disclosure is illustrative only and other aspects of the invention will become apparent to those of ordinary skill in the art.