GB2220608A

GB2220608A - Slide fasteners

Info

Publication number: GB2220608A
Application number: GB8816919A
Authority: GB
Inventors: Ching Fu Liao
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-07-15
Filing date: 1988-07-15
Publication date: 1990-01-17
Anticipated expiration: 2008-07-15
Also published as: GB2220608B; GB8816919D0

Abstract

A slide of a slide fastener comprises a pulling tab (7) having a loop (75) and a slide (8) including a body (85) and a pulling ring (80) integrally formed therewith. The loop and the pulling ring are in a chain-linking relationship with no slit existing in either. The molding device includes a first mold (L), a second mold (R) which can be separated to open the molding device, and at least one set of molding parts, each of which sets comprises at least four upper parts (1, 2, 3, 4), moveably installed in the first mold (L), and the remaining of which (5, 6) are installed in the second mold (R) so that the upper molding parts can be separated after the production of the slide (7, 8) to facilitate removal of the produced slide; each of the upper molding parts being provided with a pair of chain-linking sub-cavities (17, 18), (27, 28), (37, 38) or (47, 48) which, when the upper molding parts are brought together, combine with all other sub-cavities pairs into two independent but chain-linking cavities for forming a pair of independent but chain-linking pulling tab (7) and pulling ring (80) of a slide fastener. <IMAGE>

Description

INTEGRAL SLIDE FASTENER AND THE MOLDING PARTS THEREOF This invention relates to an integral slide fastener and the molding device for producing it.

Until today, slide fasteners have been produced by first forming a pulling tab and a slide, firstly by injection molding, and then manually assembling the pulling tab to the slide by chain-linking a ring-shaped portion of the pulling tab with a pulling ring integrally formed on the slide. The term "chain-linking" referred herein and hereafter means to link two ring-shaped (or partially ring-shaped ) members in a manner similar to the linking way of two consecutive rings in a chain. A slit is always provided in the pulling ring so that the ring-shaped portion of the pulling tab can be put into the pulling ring therethrough, and thereafter the slit must be closed so ag to prevent the disengagement of the pulling tab from the pulling ring (or the slide ).

Needless to say, the above-described conventional method for producing a slide fastener is both time-consuining and costly due to the fact that it comprises four steps including forming a pulling tab, forming a slide, assembling the pulling tab to the slide, and finally closing the slit provided on the pulling ring. In addition, manual operation is also included in the production procedure.

The primary object of this invention is to provide an integral slide fastener which is formed in a single stroke by injection molding and which does not include slit in either the pulling ring or the ring-shaped portion of the pulling tab.

Another object of this invention is to provide a molding device for forming an integral slide of a slide fastener, which comprises a pair of left and right molds, and at least one set of replaceable molding parts installed in the pair of left and right molds so as to form, together with the left and right molds, at least one pair of independent while chainlinking molding cavities for producing in a single production stroke at least one slide of slide fastener, each of which comprises a pair of independent while chain-linking pulling tab and slide. Since the molding parts can be individually replaced without changing the left and right molds, the shapes and designs of the produced slide fastener, especially of the pulling tab, can be easily changed without replacing the whole left and right molds.Consequently, the slide fasteners can be produced in a more speedy and economical manner.

Fig. 1A is a perspective view of the slide of a slide fastener in accordance with this invention; Fig. 1B is the top view of the slide as shown in Fig. 1A in a slightly reduced scale; Fig. 2A through 2D are, respectively, the perspective views of four upper molding parts for forming the pulling tab and pulling ring of a slide in accordance with this invention; Fig. 3A is a perspective view showing how the four molding parts as shown in Fig. 2A through 2D are brought together to form two independent but chain-linking molding cavities; Fig. 3B is a view similar to Fig. 3A, with the molding cavities shown from a different direction; Fig. 3C is a perspective view showing a portion of the slide as shown in Fig. 1 which is formed by the four molding parts as shown in Figs. 3A or 3B;; Fig. 4A and 4B are, respectively, the perspective views of two lower molding parts for forming, in cooperation with a pair of left and right molds and the four upper molding parts as shown in Figs. 2A through 2D, the residual portion of a slide fastener except that portion as shown in Fig. 3C; Fig. 5A is a perspective view showing the position when the two lower molding parts as shown in Figs. 4A and 4B are brought together; Fig. 5B is the perspective view of the residual portion of a slide except for the portion shown in Fig. 3C; Fig. 6 is a perspective view showing a state in which the six molding parts as shown in Figs. 2A through 2D and Figs. 4A and 4B are brought together for the production of a slide; Fig. 7 is a front view showing the shape of the produced slide fastener and some materials, left in the runner of the molds, connected with the produced slide; and Figs. 8A through 8C are top views showing the steps how the six molding parts separate from one another so as to release the produced slide fastener.

Figs. 1A and 1B show an integral slide of a slide fastener in accordance with this invention. The whole slide is integrally formed in a production stroke by injection molding and comprises a pulling tab 7 and a slide 8 including a slide body 85 and a pulling ring 80 integrally formed on the upper surface of the slide body 85 with no slit existing along the pulling ring 80 or at the junctures of the pulling ring 80 to the slide body 85. An opening 75 is provided at the lower portion of the pulling tab 7 so as to form, around the opening 75, a ring-shaped portion including the lower edge 76 of the pulling tab 7. Also a ring-shaped-portion is formed around an opening 90 provided between the pulling ring 80 and upper surface of the slide body 85.The two ring-shaped portions are in a chain-linking relationship, namely the lower edge 76 of the pulling tab 7 extends through the opening 90 and the pulling ring 80 extends through the opening 75. This integral slide can be produced by the use of a set of molding device see Figs. 6 and 8A) mainly comprising a left mold L; a right mold R; four upper molding parts 1, 2, 3 and 4 (see also Figs. 2A through 2D), among which the upper molding parts 2 and 3 are movably provided in the left mold L and the upper molding parts 1 and 4 are movably provided in the the right mold R; and two lower molding parts 5 and 6 (see also Figs.

4A and 4B) moveably provided in the left mold L and the right mold R, respectively. The constructions and functions of the upper molding parts and lower molding parts will later be explained in more detail.

As is best shown in Fig. 1B, the portion of the slide over the upper surface of the slide body 85 can be divided into four regions I, II, III and IV by two planes SS and TT.

The pulling tab 7 comprises four portions 71, 72, 73 and 74, respectively in regions I, II, III and IV. While the pulling ring 80 comprises four portions 81, 82, 83 and 84, respectively in regions I, II, III and IV. Since the pulling tab 7 and the pulling ring 80 are in chain-linking relationship, further reduction of the number of required upper molding parts to less than four will cause the problem of separating the produced slide from the molding device.

Namely, the produced slide will hinder the withdrawl of the upper molding parts or same withdrawl will hurt the produced fastener. Consequently, at least four upper molding parts are required for the production of a slide of a slide fasteners in accordance with this invention.

Figs. 2A through 2D show the constructions of four upper molding parts 1, 2, 3 and 4 each provided therein with subcavities for forming a portion of the slide, respectively, in the above-described regions I, II, III and IV. In order to clearly illustrate the construction of the sub-cavities, runners for introducing the constituting material of a slide into the cavities and guide holes for guiding an ejector rod have been omitted.

As shown in Fig. 2A, the first upper molding part 1 is provided therein with a pair of independent or noncommunicative sub-cavities (17, 18) for forming the abovementioned two portions (71, 81). Similarly, as shown in Figs.

2B, 2C and 2D, the second, third and fourth upper molding parts 2, 3 and 4 are provided therein, respectively, with a pair of independent sub-cavities (27, 28), (37, 38) and (47, 48), respectively, for forming the portions (72, 82), (73, 83) and (74, 84). Prior to the production of a slide by utilizing the molding device in accordance with this invention, the four upper molding parts 1, 2, 3 and 4 must be brought together into the position as shown in Fig. 6. In this position, the first upper molding part 1 is adjacent to the second upper molding part 2 on a surface 12, and to the fourth upper molding part 4 on a surface 14. Similarly, the second upper molding part 2 comprises two surfaces 21 and 23 which are adjacent to the first and the third upper molding parts 1 and 3, respectively, in the same state.The third upper molding part 3 comprises two surfaces 32 and 34, and the fourth upper molding part 4 comprises two surfaces 41 and 43. In addition to the above-described adjacent surfaces, each of the four upper molding parts 1, 2, 3 and 4 also comprises a guide surface 15, 25, 35 or 45. As can be seen from Fig. 2A, the guide surface 15 of the first upper molding part 1 is slant with respect to the surface 14 for a reason 'to be described later, and the situation for the guide surfaces 25, 35 and 45 is the same.

As can be seen from Fig. 3A, when the third and the fourth upper molding part 3 and 4 are brought together with their surfaces 34 and 43 abutting against each other, the sub-cavities 37 and 38 overlap, respectively, with the cavities 47 and 48 so as to form two independent sub-cavities corresponding the left half of the portion of a slide as shown in Fig 3C. Likewise, when the first and the second upper molding parts 1 and 2 are brought together in a similar manner, two independent sub-cavities corresponding to the residual half of the same portion are formed.Then, when the first, the second upper molding parts 1, 2 and the third, the fourth upper molding parts 3, 4 are further put together with the surfaces 14 and 23 overlapping with the corresponding surfaces 41 and 32, two independent and chain-linking cavities corresponding to the whole pulling tab 7 and the pulling ring 80 of a slide as shown in Fig. 3C will be formed. Fig. 3B is similar to Fig. 3A, but shows the sub-cavities 17, 27, 37 and 47 for the pulling tab 7 in a more clear manner.

Fig. 4A shows the structure of a lower molding part 5 to be provided in a left mold, Fig. 4B shows the structure of another lower molding part 6 to be provided in a right mold.

When these two lower molding parts 5 and 6 are brought together with the above-described four upper molding parts 1, 2, 3 and 4 to come onto the position shown in Fig. 6, the top surfaces 51 and 61 of the two lower molding parts 5 and 6 contact with the bottom surfaces of the upper molding parts.

The lower molding part 6 comprises a base portion 60 and an extension 62 extending from one side of the lower molding part 6 opposite the lower molding part 5 toward the latter. The extension 62 includes a V-shaped concave portion 63 formed at the free end thereof; a top surface 66 lower than the top surface 61 of the base portion 60 by a height difference equal to the thickness of the top plate 86 of the slide body 85 (see Fig. SB) so as to form a sub-cavity, together with the upper molding parts 1, 2, 3, 4 and the left and right molds, for forming a portion of the top plate 86; and a step-shaped portion 68 formed in the vicinity of the juncture of the extension 62 to the base portion 60 near the top surface 66 so as to form a sub-cavity, together with the right mold, for forming a portion 88 of the side plate of a slide (see also Fig. 5B). The lower molding part 5 comprises a base portion 50 and an extension 52 extending from one side of the molding part 5 opposite the lower molding part 6 toward the latter.

The extension 52 includes a guide slot 55 opening toward the extension 62 so as to sandwich the extension 62 therein for guiding the movement of the lower molding part 6 toward or away from the lower molding part 5; a top surface 56 partially lower than the top surface 51 of the base portion 50 by a height difference equal to the thickness of the top plate 86 of the slide body 85 (see Fig. 5B) so as to form a subcavity, together with the upper molding parts 1, 2, 3, 4 and the left and right molds, for forming a portion of the top plate 86; and a step-shaped portion 57 formed at the free end of the extension 52 near the top surface 56 so as to form a sub-cavity, together with the right mold, for forming a portion 87 of the side plate of a slide (see also Fig. SB).

During the production of the slide, when the extension 62 reaches a predetermined position for producing a slide as shown in Fig. 5A, no gap exists between the side edges of the extension 62 and of the guide slot 55, and a space 100 is formed between the V-shaped ' concave portion 63 of the extension 62 and the concave end surface 53 of the guide slot 55, with the top end and the bottom end of the space 100 being, respectively, bounded by the upper molding parts and the left mold (not shown in Fig. 5A) so as to form, during molding operation, a connecting portion 89 which connects the top plate 86 and the bottom plate 86' of the slide body 85.

The bottom plate 86' and the side plate 87', 88' connected thereto can be formed by similar structures provided on the undersurfaces of the extensions 52 and 62. Consequently, the whole slide body 85 can be produced through the cooperation of the lower molding parts 5, 6 together with the upper molding parts 1, 2, 3, 4 and the left and right molds.

When the upper and lower molding parts 1 through 6 are brought together as shown in Fig. 6, the sub-cavities 18, 28, 38 and 48 provided in the upper molding parts 1, 2, 3 and 4 see also Figs. 3A and 3B) for forming the pulling ring 80 see Fig. 3C) come into positions connecting with the subcavities provided between the upper molding parts and the lower molding parts for forming the top plate 86 of the slide body 85 ( see Fig. 5A) so as to cooperatively constitute a complete cavity (hereinunder referred to as second cavity) for forming a whole slide 8 inclusive of a slide body 85 and a pulling ring 80. As can be readily understood, the thus formed cavity for the whole slide 8 is in an independent but chainlinking relationship with a combined cavity ( hereinunder referred to as first cavity ) for the pulling tab 7 formed by the sub-cavities 17, 27, 37 and 47 as described above.

Now, referring to Fig. 7, a whole slide can be produced within a single production stroke, when the material for injection molding is charged into the molding device through a sprue (not shown) and a main runner M and then is introduced into an upper branch runner U connecting with the first cavity and a lower branch runner V connecting with the second cavity. The extra materials connected with the slide fastener can later be taken away from the slide.

Figs. 8A through 8C show, by top views, how the six molding parts 1, 2, 3, 4, 5, 6 and the left mold L and right mold R move relative to one another after a slide has been formed so as to separate the produced slide from the molding device. The upper molding parts 2, 3 and the lower molding part 5 are installed in the left mold L, and the upper molding parts 1, 4 and the lower molding part 6 are installed in the right mold R. At first, the left mold L (together with the molding parts 2, 3 and 5 ) and the right mold R ( together with the molding parts 1, 4 and 6 ) are moved away from each other along the opposite directions E and F, from the position of Fig. 8A into the position of Fig. 8B.Then, under the action of compressed springs (not shown) provided along the guide surfaces 25 and 35 of the upper molding parts 2 and 3, the upper molding parts 2 and 3, respectively, move relative to the left mold L along the directions B and C s-o as to separate from each other by.a small gap. The upper molding parts 1 and 4 move at the same time in a similar manner along the directions A and D. Consequently, the whole molding device comes into the position shown in Fig. 8C, and the produced slide is ready for being separated from the molding device by the use of an ejector rod. Though, for the purpose of illustration, the movements of the comprising members of the molding device has been divided into two steps, it is to be understood that the movements along the directions E, F and the movements along the directions A, B, C, D occur simultaneously.

Although the above description has been made with respect to the case in which two of the upper molding parts and one of the lower molding parts are installed in the left mold, and the remaining molding parts are installed in the right mold, this invention is also applicable in the case all of the four upper molding parts are installed in an upper mold, and both of the lower molding parts are installed in a lower mold if slight modifications, with respect to the molding device, are made. In addition, though the case for the production of a single slide is described above, several set of upper and lower molding parts can be installed in the same pair of left and right (or upper and lower) molds so as to produce several slide fasteners simultaneously within a single production stroke.

Claims

1. An integral slide of a slide fastener comprising a pulling tab having a ring-shaped portion, and a slide including a slide body and a pulling ring integrally formed with the slide body, the ring-shaped portion and the pulling ring being in an independent and chain-linking relationship with no slit existing in either the ring-shaped portion or the pulling-ring.

2. A molding device for producing, by injection molding, the slide of a slide fastener as described in Claim 1, including a first mold, a second mold which can be moved toward or away from the first mold so as to close or open the molding device, and at least one set of molding parts; each set of molding parts comprising: at least four upper molding parts which are moveably installed in the first mold or in the second mold so that the at least four upper molding parts can be moved away from one another after the production of the slide is completed to facilitate the separation of the produced slide from the molding device; each of the at least four upper molding parts being provided therein with a pair of independent and chainlinking sub-cavities which, when all of the at least four upper molding parts are brought together, dan be combined together with all other sub-cavities pairs into two independent but chain-linking cavities for forming a pair of independent but chain-linking pulling tab and pulling ring; each of the at least four upper molding parts being provided with a surface which is slant with respect to the direction of the relative movement between the first and the second molds so as to guide the movement of each upper molding part relative to one of the first and the second molds; and lower molding parts installed in the first and the second molds for forming, in cooperation with the two molds and the upper molding parts, the slide body of a slide fastener.

3. A molding device for producing, by injection molding, the slide of a slide fastener as described in Claim 1, including a first mold, a second mold which can be moved toward or away from the first mold so as to close or open the molding device, and at least one set of molding parts; each set of molding parts comprising: at least four upper molding parts which are moveably installed in the first mold so that the at least four upper molding parts can be moved away from one another after the production of the slide is completed to facilitate the separation of the produced slide from the molding device; each of the at least four upper molding parts being provided therein with a pair of independent but chain-linking subcavities which, when all of the at least four upper molding parts are brought together, can be combined together with all other sub-cavities pairs into two independent but chainlinking cavities for forming a pair of independent but chainlinking pulling tab and pulling ring; each of the at least four upper molding parts being provided with a surface which is slant with respect to the direction of the relative movement between the first and second molds so as to guide the movement of each of the upper molding part relative to the first mold; and lower molding parts moveably installed in the second mold for forming, in cooperation with the first and the second molds and the upper molding parts, the slide body of a slide fastener.