CA2106720C - Needle for use as part of a plastic fastener dispensing tool - Google Patents

Abstract

A needle for use as part of a fastener dispensing tool adapted for dispensing plastic fasteners of the type typically used to attach tags to products for marking and identification. The needle is made from a single sheet of metal by a stamping and/or rolling technique, and comprises an elongated, generally cylindrical, hollow, slotted member having a stem portion and a base portion. The stem portion terminates at its front end in a relatively sharp tip. The base portion is sized and shaped for insertion in an opening in the nose of the tool and includes a spring tab which is sized and shaped to releasably engage a recessed area formed in one of the walls of the opening so as to prevent unintended removal of the needle from the tool.

Description

- ' 21 0672n NEEDLE FOR USE AS PART OF A PLASTIC
FASTENER DISPENSING TOOL
BACKGROUND OF THE INVENTION
The present invention relates generally to tools for use in dispensing plastic 5 fasteners and more particularly to needles which are used in such tools.
Plastic fasteners are widely used in commerce to attach tags or other items to articles in a manner which minimizes the risk of inadvertent detachment there-from. One type of plastic fastener is manufactured in the form of fastener stockcomprising a pair of continuously connected, elongated side members which are 10 interconnected by a plurality of thin transverse cross links. Typically, one side member comprises a plurality of end-bars or T-bars joined together by severable connectors. The fastener stock is usually produced by molding or stamping from flexible plastic materials, such as nylon, polyethylene, and polypropylene. Additional information pertaining to fastener stock may be obtained from the following com-monly assigned U.S. patents, U.S. Pat. No.4,955,475, issued September 11,1990;
U.S. Pat. No. 4,456,161, issued June 26, 1984; U.S. Pat. No. 4,121,487, issued October 24, 1978; and U.S. Pat. No. 3,103,666, issued September 17, 1963.
The above-described fastener stock is typically loaded into a dispensing tool, often referred to as a "tagger gun". A tagger gun normally includes a hollow needle 20 having a longitudinal slot extending over its length. The fastener stock is inserted into the tagger gun behind the needle. Upon actuation of a trigger mechanism in the gun, an individual fastener is separated from the fastener stock and is inserted into the desired article of commerce through the needle.
In U.S. Patent No. 4,273,279, a typical needle having a single part 25 construction is described. The needle includes a shank or "stem" portion which has a relatively sharp tip to permit penetration into the article to be B

210672~

attached and an integrally formed substantially cylindrical base portion. The shank portion is hollow to permit the T-bar end of the fastener to pass therethrough and has a longitudinal slot to permit the filament of the fastener to extend therefrom as the T-bar end moves through the needle. The base portion includes a central bore with an inner diameter equal to the inner diamter of the hollow shank. The base portion also has a longitudinal slot aligned with the slot in the shank. The needle is made by machining the shank portion and the base portion from a single piece of metal. As can readily be appreciated, however, machining metal into a desired shape can be a rather arduous and time-consuming task which allows little margin for error.
Also disclosed in U.S. Pat. No. 4,273,279 is a needle assembly having a conventional two part structure. The needle assembly includes a shank portion stamped from a piece of a steel and a base portion which is formed of plastic and is molded around the shank portion. One disadvantage with this type of needle, however, is that the molding process is rather expensive, accounting for an overwhelming percentage of the total cost of manufacturing the needles.
Because needles used in tagger guns tend to break frequently and require replacement, they are typically removably mounted in an opening formed in the front end or "nose" of the tagger gun and are releasably secured therein by means of a locking mechanism in the tagger gun.
For example, as shown in Figs. 21 and 22 of U.S. Pat. No. 4,456,161, the needle locking mechanism includes a locking pin, which engages a corresponding recessedarea formed in the needle. The locking pin is also provided with a cut-out slot which provides a passageway for insertion and removal of the needle. The locking pin is biased in its locking position by means of a spring mounted in the tagger gun. When the locking pin is pushed towards the spring to compress it, the slot on the locking pin aligns with the needle to free it for removal. Preferably, that portion of the locking pin engaging the recessed area of the needle in locking position is rectangular or square in cross section.
Unfortunately, the above-described needle locking mechanism suffers from certain disadvantages. For example, the needle may be inserted into the opening in 5 the tagger gun in any one of an infinite number of angular orientations. An inherent problem with this mounting procedure is that it is not intuitively obvious or readily apparent as to what angular orientation is correct. If the angular orientation of the needle is incorrect, the locking pin will not properly engage the recessed area in the needle, frequently resulting in needle breakage or in the jamming of the needle in the 10 tagger gun, or in an ineffective locking of the needle. Moreover, one or morecomponents of the locking mechanism may break or require replacement after repeated or prolonged use.
Another patent of interest to the present invention is the commonly assigned U.S. Pat. No. 4,998,661, issued March 12, 1991. In this patent, a needle assembly 15 adapted for removable mounting on the front end of a tagger gun is disclosed. The needle assembly comprises a needle encased in a holder which may be easily secured to and removed from the front end of the tool, the holder defining in conjunction with the remainder of the tool at least a major portion of the feed track.
In a preferred construction of the needle assembly, the needle is a hollow slotted 20 metal structure and the holder is comprised of plastic which is injection molded around the needle.
In U.S. Patent No. 4,877,172 there is described and illustrated in Figure 4 the use of a tapered needle locking screw for locking an inserted needle in place.
Although the needle locking screw provides a secure, snug engagement of an 25 inserted needle, it still requires precise alignment of the needle before locking.

SUMMARY OF THE INVENTION
It is an object of the present invention to provide a new and improved needle for use as part of a tool for dispensing plastic fasteners.
It is another object of the present invention to provide a needle as described 5 above which can be removably mounted in the nose of a fastener dispensing tool and releasably secured in place.
It is yet another object of the present invention to provide a needle as described above which does not require an extraneous needle locking mechanism for releasably securing the needle in the nose of the fastener dispensing tool and, 10 therefore, can be more easily inserted into and removed from the nose of the fastener dispensing tool.
It is still another object of the present invention to provide a needle as described above which can be made by a more economical manufacturing process than is typically available for existing needles.
In accordance with the objects of the present invention as broadly stated above, there is provided a needle for use as part of a fastener dispensing tool, the needle comprising an elongated tubular member having a stem portion and a base portion, a part of said base portion being adapted cooperatively to engage an opening in the fastener dispensing tool and including first and second spring tabs for 20 releasably securing said base portion within said opening in the fastener dispensing tool, said stem portion being aligned with said base portion, said needle having a longitudinal slot extending the combined length of the base and stem portions.
Moreover, according to the present invention there is also provided a method of making a needle adapted to be removably mounted within an opening formed in 25 a fastener dispensing tool, the method comprising the steps of: (a) providing a sheet 2t 06720 of metal; and (b) processing the sheet of metal by a technique including stamping, rolling, or a combination of stamping and rolling to form a tubular member having a longitudinal slot, said tubular member including a base portion sized and shaped for insertion into the opening in the fastener dispensing tool, said base portion having 5 a pair of spring tabs for releasably securing said base portion within the opening in the fastener dispensing tool.
In another broad aspect, the present invention relates to a method for removably mounting a needle in a fastener dispensing tool comprising the steps of:
(a) providing an opening in the fastener dispensing tool sized and shaped to receive 10 said needle; (b) providing a needle including a stem portion and a base portion, said base portion being sized and shaped for insertion into the opening in the fastener dispensing tool and having a pair of spring tabs for releasably securing said base portion within the opening in the fastener dispensing tool; and (c) inserting said base portion into said opening whereby said spring tab releasably secures said base 15 portion within said opening in said fastener dispensing tool.
Preferably, the base portion and the stem portion of the needle are made from a single sheet of metal by a stamping and/or rolling technique. In addition, the base portion of the needle is preferably shaped to include a second spring tab. A first portion of one of the spring tabs is sized and shaped to releasably engage a recessed 20 area -4(a)-210672~

formed in the nose so as both to prevent unintended removal of the base portion therefrom and to limit rearward insertion of the base portion into the nose. A second portion of the same tab is sized and shaped to engage another portion of the nose so as to prevent vertical movement of the base portion therewithin. The other spring tab serves as a registration member to align the base portion in its desired longitudinal, vertical and axial orientations.
Additional objects, as well as features and advantages, of th~ present inventionwill be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention. In the description, lo reference is made to the accompanying drawings which forms a part thereof and in which is shown by way of illustration specific embodiments for practicing the invention.
These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are hereby incorporated into and constitute a part of this specification, illustrate preferred embodiments of the invention and, together with the description, serve to explain the principles of the invention. In these drawings wherein like reference numerals represent like parts:
Fig. 1 is a perspective view of one embodiment of a needle adapted for use as part of a tool for dispensing plastic fasteners, the needle being constructed according to the teachings of the present invention;
Fig. 2 is a rear view of the needle shown in Fig. 1;
Fig. 3 is a side view of the needle shown in Fig. 1;
Fig. 4 is a top view of the needle shown in Fig. 1;
Fig. 5 is a top, fragmentary view of the front end of a fastener dispensing toolillustrating the opening into which the needle of Fig. 1 may be removably mounted;
Fig. 6 is a front, fragmentary view of the front end of the fastener dispensing tool shown in Fig. 5;
Fig. 7 is a top, fragmentary view showing the needle of Fig. 1 mounted in the opening in the tool of Fig. 5;
Fig. 8 is a front, fragmentary view showing the needle of Fig. 1 mounted in the opening of Fig. 5, the components of the tool located behind the slot not being shown for purposes of clarity;
Fig. 9 is a side, fragmentary view showing the needle of Fig. 1 mounted in the opening of Fig. 5;
Fig. 10 is a fragmentary section view taken along line A-A of Fig. 9;
Fig. 11 is a perspective view of a second embodiment of a needle adapted for useas part of a fastener dispensing tool, the needle being constructed according to the teachings of the present invention;

Fig. 12 is a front, fragmentary view of the front end of a fastener dispensing tool illustrating the opening into which the needle of Fig. 11 may be removably mounted;
Fig. 13 is a perspective view of a third embodiment of a needle adapted for use as part of a fastener dispensing tool, the needle being constructed according to the teachings of the present invention;
Fig. 14 is a top view of a fourth embodiment of a needle adapted for use as partof a fastener dispensing tool, the needle being constructed according to the teachings of the present invention;
Fig. 15 is a front view of the needle shown in Fig. 14;
Fig. 16 is a front, fragmentary view of the nose of a fastener dispensing tool into which the needle of Fig. 14 may be removably mounted;
Fig. 17 is a fragmentary, right side view of the nose of the fastener dispensing tool shown in Fig. 16;
Fig. 18 is a front, fragmentary view showing the needle of Fig. 14 mounted in the nose of Fig. 16; and Fig. 19 is a fragmentary, right side view showing the needle of Fig. 14 mounted in the nose of Fig. 16.

21~6720 -DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings and more particularly to Figs. 1 through 4, there is shown one embodiment of a needle for use as part of a tool for dispensing plastic fasteners, the needle being constructed according to the teachings of the present invention and represented generally by reference numeral 11.
Needle 11, which is preferably made by stamping and/or rolling a single sheet ofmetal, comprises an elongated, hollow, cylindrically shaped stem portion 13. Stem portion 13 terminates at its forward end with a relatively sharp tip 15 and is provided with a longitudinally extending slot 17. The inner diameter of stem portion 13 is somewhat l0 larger than the outer diameter of the T-bar end of a plastic fastener (not shown) to be dispensed through needle 11. The width of slot 17 is sufficiently large to accommodate the cross-link portion of the fastener to be dispensed through the needle.
Needle 11 also includes a base portion 19. Base portion 19 includes a cylindrically shaped bottom section 21 which has an inner diameter substantially equal to the inner diameter of stem portion 13 and is aligned therewith. A longitudinally extending slot 23 is formed in bottom section 21 and is aligned with slot 17 of stem portion 13 so as to permit the cross-link of the fastener being dispensed by the tool to extend from the T-bar end as the latter is pushed through the needle. Base portion 19 also includes a pair of spring tabs 24 and 27 which extend generally upwardly and 20 outwardly on opposite sides of slot 23.
As will hereinafter be discussed in greater detail, base portion 19 of needle 11 is sized and shaped for insertion into an opening 31 formed at the front end or nose 33 of a tagger gun, see Figs. 5 and 6. When being assembled, base portion 19 of needle 11 is inserted into opening 31 from front 34 of front end 33. When base portion 19 is inserted into opening 31, spring tabs 24 and 27 press against the inner walls 37 and 39 of opening 31. Tab 24 includes a first portion 25 and a second portion 26. First portion - - 21067~

25 is shaped to fit into a recessed area of opening 31 in such a way as to prevent the unintended removal of base portion 19 from opening 31. In addition, when mounted in place, the top of first portion 25 of tab 24 extends up above opening 31 in such a way as to permit a user to grasp it and to push it inwardly out of engagement with the recessed area so that base portion 19 may be removed from opening 31. Second portion 26 of tab 24 is shaped and located relative to first portion 25 so as to abut another portion of opening 31 in such a way as to minimize vertical movement of base portion 19 within opening 31. Tab 27 serves as a registration member which helps to keep the needle in its desired longitudinal, vertical and axial orientation when mounted on the tagger gun.
Preferably, needle 11 is made of a metal of the type typically used in tagger gun needles. Examples of suitable metals for needle 11 are a beryllium/copper alloy,stainless steel, and p~ated or coated steel. As can readily be appreciated, one advantage to the construction of the needle of the present invention is that the needle can be manufactured in its entirety by a stamping and/or roll forming process. Such a process is considerably less expensive and time-intensive than the machining process or the combination stamping/molding process described above inconnection with the manufacture of conventional needles.
As can be seen in Figs. 5 and 6, opening 31 in front end 33 is of a general slottype configuration extending in from front 34 of nose 33 and down from the top 34-2 of nose 33. Opening 31 is defined by a curved bottom wall 35 and a pair of upwardlyextending side walls 37 and 39. Bottom wall 35 is shaped to receive bottom section 21 of base 19. Side walls 37 and 39 are shaped to receive tabs 24 and 27, respectively.
Side wall 37 includes an inwardly tapering front portion 40 and a rearwardly disposed, generally rectangularly shaped, recessed area 41. Front portion 40 includes a notch 42, which is sized and shaped to receive second portion 26 of tab 24. Notch 42 is defined in part by a top surface 42-1, which serves to limit vertical movement of second portion 26 of tab 24 when base portion 19 is inserted into opening 31 (see Fig.
8). Area 41 is defined by a rear surface 41r, a side surface 41s, and a front surface 41f.
Area 41 is appropriately dimensioned so that, when first portion 25 of tab 24 is inserted thereinto (i.e., when base portion 19 is fully inserted into opening 31), longitudinal movement of base portion 19 within opening 31 is prevented.
Side wall 39 includes a notch 43, which is sized and shaped to recieve tab 27.
Notch 43 is defined in part by a top surface 43-1, which serves to limit upward movement of tab 27, and a rear surface 43-2, which serves to limit insertion of base portion 19 into opening 31.
Walls 37 and 39 also limit rotational movement of base portion 19 by engaging tabs 24 and 27.
The front end of opening 31 (which spans from the front surface 40f of portion 40 across notch 43) is approxirnately the same width as the rear end of needle 11 in its relaxed position. Consequently, a user may mount needle 11 in opening 31 simply by aligning the rear end of needle 11 with the front end of opening 31 and then sliding needle 11 into opening 31 until first portion 25 of spring tab 24 locks into place in area 41. There is no need to push tab 24 inwardly before pushing base portion 19 through opening 31. Thus, installation of needle 11 in tool 31 can be achieved in one motion and, assuming that nose 33 is kept stationary, can be accompiished using only one hand .
Referring now to Figs. 7 through 9, there are- shown top, front, and side fragmentary views, respectively, of needle 11 fully inserted into opening 31. As can be seen in Fig. 9, the top of first portion 25 of tab 24 extends a short distance out of the top of opening 31 to permit it to be manipulated by a user, for instance, in removing needle 11 from the tool. This may be done, as seen in Fig. 7, by pushing hrst portion 25 towards surface 43 (in the direction of arrow A) until it has cleared surface 41f and then pushing (or pulling) base portion through the front of opening 31.
Referring now to Fig. 10, there is shown a section view of needle 11 mounted in opening 31. As can be seen, that portion of needle 11 that is mounted within opening - 31, i.e., base portion 19, has an outer diameter d and a length 1. It is believed that the ratio of diameter to length (dtl) is indicative of the relative strength of needle retention as well as the strength and durability of the tool, with smaller ratios indicating greater strength and greater ratios indicating lesser strength.
Comparing the d/l ratio of needle 11 to that for conventional needles of the type described in U.S. Pat. No. 4,273,279, one finds needle 11 to have a smaller d/l ratio since the lengths of the respective base portions are substantially equal whereas the diameter of the base portion of needle 11 is considerably smaller than the diameter of the base portion of conventional needles. Consequently, it is believed that needle 11 is more fully retained and, therefore, more likely to remain in proper alignment than conventional needles of the type described above.
Referring now to Fig. 11, there is shown a second embodiment of a needle for use as part of a fastener dispensing tool, the needle being constructed according to the teachings of the present invention and being represented generally by reference numeral 71 .
Needle 71, which, like needle 11, is preferably made by stamping and/or rolling a sheet of metal, such as a beryllium/copper alloy, comprises a slotted, hollow,cylindrically-shaped stem portion 73 substantially identical to stem portion 13 of needle 11. Needle 71 also includes a base portion 75, which includes a slotted cylindrically shaped bottom section 77, which has an inner diameter substantially equal to the inner diameter of stem portion 73 and which is aligned therewith. In addition, base portion 75 includes a generally upwardly extending removal tab 79 and a generally laterally extending wing 81. As can be seen, wing 81 is split to include a spring tab 83, which functions to releasably secure base portion 75 within a suitably shaped slot formed in the nose of a fastener dispensing tool. (See, for example, Fig. 12 which illustrates a generally T-shaped slot 85 formed in the nose of a fastener dispensing tool 87. Depression of spring tab 83 within slot 85 for purposes of removing needle 71 from tool 87 may be achieved by pushing downwardly on a release button 89 integrally formed on tagger gun 87.) Referring now to Fig. 13, there is shown a third embodiment of a needle for use as part of a fastener dispensing tool, the needle being constructed according to the l0 teachings of the present invention and being represented generally by reference numeral 101.
Needle 101 is substantially identical in construction and composition to needle 71, the only difference between needle 71 and needle 101 being that needle 101 does not include a removal tab 79. Like needle 71, needle 101 may be releasably secured within slot 85 of tool 87 (see Fig. 12).
Referring now to Figs.14 and 15, there is shown a fourth embodiment of a needle for use as part of a fastener dispensing tool, the needle being represented generally by reference numeral 151.
In contrast with needle 11, which is primarily intended for use with tagger guns20 of the type wherein a T-bar of a fastener is loaded into the rear end of the needle through the longitudinal slot thereof, needle 151 is intended primarily for use with, but is not limited to use with, tagger guns of the type wherein the T-bar of a fastener is loaded into the rear end of the needle from a direction generally perpendicular to the longitudinal slot of the needle. An example of a tagger gun having such a loading mechanism is sold by Dennison Manufacturing Co. under the trademark MARK ll PISTOL-GRIP SWIFTACHER TOOL.

210~720 Needle 151, which may be made from the same materials used to make needle 11, is preferably made by stamping and/or rolling a single sheet of metal. As can be seen, needle 151 comprises an elongated, hollow, cylindrically shaped stem portion 153.
Stem portion 153 terminates at its forward end with a relatively sharp tip 155 and is provided with a longitudinally extending slot 157. The inner diameter of stem portion 153 is somewhat larger than the outer diameter of the T-bar end of a plastic fastener (not shown) to be dispensed through needle 151. The width of slot 157 is sufficiently large to accommodate the cross-link portion of the fastener to be dispensed through the needle.
Lo Needle 11 also includes a base portion 159. Base portion 159 includes a bottom section 161 which is shaped to define a longitudinally extending slot 163. Slot 163 is aligned with slot 157 of stem portion 153 so as to permit the cross-link of the fastener being dispensed by the tool to extend from the T-bar as the latter is pushed through the needle. The front portion of bottom section 161 is generally cylindrical in shape and has an inner diameter substantially equal to the inner diameter of stem portion 153. The rear portion of bottom section 161 is shaped to define a V-shaped cutting element 162, which may be used to sever an individual fastener from fastener stock.
Base portion 159 also includes a pair of spring tabs 165 and 167 which extend outwardly from opposite sides of slot 163. Tab 165 includes a first portion 166 and a '~ second portion 167. First portion 166 and second portion 167 perform substantially the same functions as first portion 25 and second portion 26 of tab 24, respectively. Tab 167, in addition to performing substanially the same functions as tab 27 of needle 11, is rounded to form a shelf 168, upon which a T-bar rests as it is loaded into needle 151 in the direction indicated by arrow B.

Referring now to Figs. 16 and 17, there are shown front and right side views, respectively, of a tagger gun nose 171 into which needle 151 may be removably mounted. Needle 151 is shown mounted in nose 171 in Figs. 18 and 19.
The embodiments of the present invention described above are intended to be merely exemplary and those skilJed in the art shall be able to make numerous variations and modifications to it without departing from the spirit of the present invention. All such variations and modifications are intended to be within the scope of the present invention as defined by the appended claims.

Claims (17)

1. A needle for use as part of a fastener dispensing tool, the needle comprising an elongated tubular member having a stem portion and a base portion, a part of said base portion being adapted cooperatively to engage an opening in the fastener dispensing tool and including first and second spring tabs for releasably securing said base portion within said opening in the fastener dispensing tool, said stem portion being aligned with said base portion, said needle having a longitudinal slot extending the combined length of the base and stem portions.

2. The needle as claimed in claim 1 wherein said first spring tab is sized so that when said needle is inserted into said opening of said fastener dispensing tool at least a portion of said first spring tab extends partially out of said opening so that said first spring tab can be manipulated by a finger of a person.

3. The needle as claimed in claim 1 wherein said first spring tab includes a portion for keeping said base portion from moving upwardly when said needle is seated within said opening.

4. The needle as claimed in claim 1 wherein said elongated, tubular member also includes means for aligning the needle in a desired orientation when seated in said opening in said fastener dispensing tool.

5. The needle as claimed in claim 4 wherein said first and second spring tab formed on said base portion are located on opposite sides of said slot.

6. The needle as claimed in claim 5 wherein said first spring tab and said second spring tab extend outwardly in substantially different directions.

7. The needle as claimed in claim 5 wherein said first spring tab and said second spring tab extend outwardly in substantially the same direction.

8. The needle as claimed in claim 1 wherein said stem portion and said base portion are formed from a single piece of material.

9. The needle as claimed in claim 6 wherein the two spring tabs extend out in opposite directions.

10. The needle as claimed in claim 9 wherein said base portion includes a V shaped cutting element.

11. The needle as claimed in claim 5 wherein said stem portion and said base portion are formed from a single sheet of metal.

12. The needle as claimed in claim 11 wherein said single sheet of metal is selected from the group consisting of a beryllium/copper alloy, stainless steel, and plated or coated steel.

13. A method of making a needle adapted to be removably mounted within an opening formed in a fastener dispensing tool, the method comprising the steps of:
a. providing a sheet of metal; and b. processing the sheet of metal by a technique including stamping, rolling, or a combination of stamping and rolling to form a tubular member having a longitudinal slot, said tubular member including a base portion sized and shaped for insertion into the opening in the fastener dispensing tool, said base portion having a pair of spring tabs for releasably securing said base portion within the opening in the fastener dispensing tool.

14. A method for removably mounting a needle in a fastener dispensing tool comprising the steps of:
a. providing an opening in the fastener dispensing tool sized and shaped to receive said needle;
b. providing a needle including a stem portion and a base portion, said base portion being sized and shaped for insertion into the opening in the fastener dispensing tool and having a pair of spring tabs for releasably securing said base portion within the opening in the fastener dispensing tool;
and c. inserting said base portion into said opening whereby said spring tab releasably secures said base portion within said opening in said fastener dispensing tool.

15. The method as claimed in claim 15 wherein at least a portion of a said spring tab is sized and shaped to extend partially out of said opening.

16. The method as claimed in claim 14 wherein said opening includes a recessed area adapted to receive a said spring tab when said base portion is fully inserted into said opening so as to prevent said base portion from being accidentally removed from said opening or from being further rearwardly inserted into said opening.

17. The method as claimed in claim 14 wherein said base portion and said stem portion are formed from a single sheet of metal.