Patent Publication Number: US-2023148715-A1

Title: Plastic product disposed on a strap

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an injection molding product, and more specifically, to a plastic product disposed on a strap with a better aesthetic appearance and an enhanced combination strength. 
     2. Description of the Prior Art 
     A soft strap can be combined with a plastic product to form an assembly, e.g., an injection zipper puller assembly, also called as an injection zipper slider assembly, or a bead string assembly, which is widely used on clothes, luggage and bags. The plastic product can be formed on an end portion of the strap and manufactured by a single injection molding process. 
     However, since the strap is flexible and extendable, it is difficult to fix the end portion of the strap during the single injection molding process. A displacement of the end portion of the strap may cause the end portion of the strap to be exposed out of and not completely covered by the plastic product, which not only negatively affects aesthetic appearance and increases a defect rate but also makes the plastic product and the strap separate from each other easily. 
     For example, please refer to  FIG.  16   .  FIG.  16    is a diagram of an assembly formed by a plastic product and a strap  1 ″ in the prior art. As shown in  FIG.  16   , since an upper injection mold  51  and a lower injection mold  52  of an injection mold assembly only can clamp a left outer portion of the strap  1 ″ outside a mold cavity  50 , an end portion  10 ″ of the strap  11 ″ inside the mold cavity cannot be fixed, so that the end portion of the strap  11 ′ might be displaced or deformed by the melted plastic material to move out of the surface of the plastic material during injection of the plastic material. Therefore, the assembly not only has a poor aesthetic appearance and increases a defect rate but also makes the plastic product and the strap  11 ″ separate from each other easily. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an objective of the present invention to provide a plastic product disposed on a strap with a better aesthetic appearance and an enhanced combination strength for solving the aforementioned problem. 
     In order to achieve the aforementioned objective, the present invention discloses a plastic product disposed on a strap. The strap is a soft string type textile. The plastic product includes a first injection molding portion and a second injection molding portion. The second injection molding portion is combined with the first injection molding portion to form the plastic product. An end portion of the strap protrudes out of the first injection molding portion and is completely covered by the second injection molding portion. A length of the first injection molding portion along a longitudinal direction of the strap is less than a length of the plastic product along the longitudinal direction of the strap, and a protruding length of the end portion of the strap protruding out of the first injection molding portion along the longitudinal direction of the strap is less than half of a thickness of the second injection molding portion along a radial direction of the strap perpendicular to the longitudinal direction of the strap. 
     According to an embodiment of the present invention, a parting line is formed on an outer surface of the plastic product. 
     According to an embodiment of the present invention, the thickness of the second injection molding portion along the radial direction of the strap is equal to a maximum thickness of the plastic product along the radial direction of the strap. 
     According to an embodiment of the present invention, a combining interface of the first injection molding portion and the second injection molding portion includes a flat surface structure or an inflection surface structure. 
     According to an embodiment of the present invention, a combining interface of the first injection molding portion and the second injection molding portion includes a step-shaped structure. 
     According to an embodiment of the present invention, the strap is a rope. 
     According to an embodiment of the present invention, the plastic product is formed in a shape of a zipper slider or a zipper puller. 
     According to an embodiment of the present invention, the first injection molding portion and the second injection molding portion are made of identical material. 
     According to an embodiment of the present invention, the thickness of the second injection molding portion along the radial direction of the strap is equal to a maximum thickness of the plastic product along the radial direction of the strap. 
     According to an embodiment of the present invention, a combining interface of the first injection molding portion and the second injection molding portion includes a flat surface structure or an inflection surface structure. 
     According to an embodiment of the present invention, a combining interface of the first injection molding portion and the second injection molding portion includes a step-shaped structure. 
     According to an embodiment of the present invention, the strap is a string. 
     According to an embodiment of the present invention, the plastic product is formed in a shape of a zipper slider or a zipper puller. 
     According to an embodiment of the present invention, the first injection molding portion and the second injection molding portion are made of identical material. 
     In summary, in the present invention, the plastic product is formed by the first injection molding portion and the second injection molding portion combined with the first injection molding portion. Furthermore, the length of the first injection molding portion along the longitudinal direction of the strap is less than the length of the plastic product along the longitudinal direction of the strap, and the protruding length of the end portion of the strap protruding out of the first injection molding portion is less than half of the thickness of the second injection molding portion along the radial direction of the strap perpendicular to the longitudinal direction of the strap. Therefore, the present invention can ensure the end portion of the strap to be completely covered by the first injection molding portion and the second injection molding portion and can solve a conventional problem that an end portion of a strap cannot be completely covered by a conventional plastic product. Besides, in the present invention, since the end portion of the strap is configured to protrude out of the first injection molding portion and completely be covered by the second injection molding portion, the end portion of the strap protruding out of the first injection molding portion and covered by the second injection molding portion can act as a fixing anchor, which not only enhances a combination strength of the first injection molding portion and the second injection molding portion but also enhances a combination strength of the plastic product and the strap. The present invention not only has a better aesthetic appearance and reduces a defect rate but also has enhanced combination strength for preventing the plastic product and the strap from separating from each other. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a sectional diagram of an assembly formed by a plastic product and a strap according to a first embodiment of the present invention. 
         FIG.  2    is a sectional diagram illustrating a combining interface of a first injection molding portion and a second injection molding portion of the plastic product according to the first embodiment of the present invention. 
         FIG.  3    is a sectional diagram of an assembly formed by a plastic product and a strap according to a second embodiment of the present invention. 
         FIG.  4    is a sectional diagram illustrating a combining interface of a first injection molding portion and a second injection molding portion of the plastic product according to the second embodiment of the present invention. 
         FIG.  5    is a sectional diagram of an assembly formed by a plastic product and a strap according to a third embodiment of the present invention. 
         FIG.  6    is a sectional diagram illustrating a combining interface of a first injection molding portion and a second injection molding portion of the plastic product according to the third embodiment of the present invention. 
         FIG.  7    is a sectional diagram of an assembly formed by a plastic product and a strap according to a fourth embodiment of the present invention. 
         FIG.  8    is a sectional diagram illustrating a combining interface of a first injection molding portion and a second injection molding portion of the plastic product according to the fourth embodiment of the present invention. 
         FIG.  9    is a sectional diagram of an assembly formed by a plastic product and a strap according to a fifth embodiment of the present invention. 
         FIG.  10    is a sectional diagram illustrating a combining interface of a first injection molding portion and a second injection molding portion of the plastic product according to the fifth embodiment of the present invention. 
         FIG.  11    to  FIG.  14    are diagrams of the assembly at different views according to the first embodiment of the present invention. 
         FIG.  15    is a flow chart of a method of disposing the plastic product on the strap according to the first embodiment of the present invention. 
         FIG.  16    is a diagram of an assembly formed by a plastic product and a strap in the prior art. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. The directional terminology is used for purposes of illustration and is in no way limiting. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
     Please refer to  FIG.  1   ,  FIG.  2    and  FIG.  11    to  FIG.  14   .  FIG.  1    is a sectional diagram of an assembly P 1  formed by a plastic product  2   a  and a strap  1   a  according to a first embodiment of the present invention.  FIG.  2    is a sectional diagram illustrating a combining interface  20   a  of a first injection molding portion  21   a  and a second injection molding portion  22   a  of the plastic product  2   a  according to the first embodiment of the present invention.  FIG.  11    to  FIG.  14    are diagrams of the assembly P 1  at different views according to the first embodiment of the present invention. As shown in  FIG.  1   ,  FIG.  2    and  FIG.  11    to  FIG.  14   , the assembly P 1  is formed by the strap  1   a  and the plastic product  2   a  combined with the strap  1   a.  The strap  1   a  can be a soft string type textile. The plastic product  2   a  can cover an end portion  10   a  of the strap  1   a  and formed by the first injection molding portion  21   a  and the second injection molding portion  22   a  combined with the first injection molding portion  21   a.    
     As shown in  FIG.  1    and  FIG.  2   , the strap  1   a  has a first dimension along a longitudinal direction and a second dimension along a radial direction perpendicular to the longitudinal direction, and the first dimension is much greater than the second dimension. In other words, the strap  1   a  can have a greater length along an x-axis direction shown in  FIG.  1    and  FIG.  2    and a shorter radius along a y-axis direction shown in  FIG.  1    and  FIG.  2   . 
     Furthermore, as shown in  FIG.  1    and  FIG.  2   , the end portion  10   a  of the strap  1   a  protrudes out of the first injection molding portion  21   a  and completely covered by the second injection molding portion  22   a.    
     Specifically, a length Ll of the first injection molding portion  21   a  along the longitudinal direction of the strap  1   a  is less than a length L 2  of the plastic product  2   a  along the longitudinal direction of the strap  1   a,  and a protruding length L 3  of the end portion  10   a  of the strap  1   a  protruding out of the first injection molding portion  21   a  along the longitudinal direction is less than half of a thickness H of the second injection molding portion  22   a  along the radial direction of the strap  1   a  perpendicular to the longitudinal direction of the strap  1   a.    
     More specifically, the thickness H of the second injection molding portion  22   a  along the radial direction of the strap  1   a  can be equal to a maximum thickness of the plastic product  2   a  along the radial direction of the strap  1   a.  Furthermore, the length L 2  of the plastic product  2   a  along the longitudinal direction of the strap  1   a  can be equal to a maximum length of the plastic product  2   a  along the longitudinal direction of the strap  1   a.    
     As shown in  FIG.  11    to  FIG.  14   , the plastic product  2   a  can be manufactured by a double injection molding process, i.e., the first injection molding portion  21   a  and the second injection molding portion  22   a  can be manufactured by two different injections, and therefore, a parting line  23   a  is formed on an outer surface of the plastic product  2   a.    
     In this embodiment, as shown in  FIG.  2   , the combining interface  20   a  of the first injection molding portion  21   a  and the second injection molding portion  22   a  includes an inflection surface structure. Specifically, the combining interface  20   a  can include a first flat surface structure parallel to the longitudinal direction of the strap  1   a  and coincided with a central axis of the strap  1   a  and a second flat surface structure perpendicular to the longitudinal direction of the strap  1   a,  i.e., parallel to the y-axis direction, and connected to the first flat surface structure. In another embodiment, instead of the inflection surface structure, the combining interface of the first injection molding portion and the second injection molding portion can include a flat surface structure, a step-shaped structure or any other shape structure. 
     The first injection molding portion  21   a  and the second injection molding portion  22   a  can be made of plastic material or rubber material. Preferably, the first injection molding portion  21   a  and the second injection molding portion  22   a  can be made of identical material, so as to achieve an enhanced combination strength of the first injection molding portion  21   a  and the second injection molding portion  22   a.    
     Specifically, the strap  1   a  can be a string. A radial cross section of the string can have a circular shape. The plastic product  2   a  can be formed in a shape of a zipper slider or a zipper puller. The assembly P 1  can be an injection zipper puller assembly, also called as an injection zipper slider assembly, used on a cloth, a luggage and a bag for cooperating with a zipper. 
     Besides, the numbers of the plastic product, the first injection molding portion and the second injection molding portion are not limited to the this embodiment. In other words, according to practical demands, there can be one or more plastic products disposed on a strap, and the plastic product can include one or more first injection molding portions and one or more second injection molding portions. As shown in  FIG.  10    to  FIG.  14   , in this embodiment, there can be only one plastic product  2   a  disposed on the end portion  10   a  of the strap  1   a,  and the plastic product  2   a  can be formed by two first injection molding portions  21   a  and one second injection molding portion  22   a.  In another embodiment, there can be two plastic products disposed on the end portion of the strap and separated from each other, and each plastic product can include one first injection molding portion and one second injection molding portion. 
     In addition, the shapes of the plastic product, the first injection molding portion, the second injection molding portion and the parting line are not limited to the aforementioned embodiments. It depends on practical demands and can be determined by an injection mold assembly. 
     Please refer to  FIG.  15   .  FIG.  15    is a flow chart of a method of disposing the plastic product  2   a  on the strap  1   a  according to the first embodiment of the present invention. As shown in  FIG.  15   , the method includes following steps: 
     Step S 1 : Place a continuous strap  1 ′ between a first upper injection mold  31  and a first lower injection mold  32  of a first injection mold assembly  3 , and inject melted plastic material into a mold cavity  30  formed between the first upper injection mold  31  and the first lower injection mold  32  to manufacture the first injection molding portion  21   a  on the continuous strap 
     Step S 2 : Cut the continuous strap  1 ′ to obtain the strap  1   a  having the end portion  10   a  protruding out of the first injection molding portion  21   a;  and 
     Step S 3 : Place the end portion  10   a  of the strap  1   a  and the first injection portion  21   a  between a second upper injection mold  41  and a second lower injection mold  42  of a second injection mold assembly  4 , and inject melted plastic material into a mold cavity  40  formed between the second upper injection mold  41  and the second lower injection mold  42  to manufacture the second injection molding portion  22   a  completely covering the end portion  10   a  of the strap  1   a,  so as to obtain the plastic product  2   a  disposed on the strap  1   a.    
     In step S 1 , the first upper injection mold  31  and the first lower injection mold  32  can cooperatively clamp a left outer portion and a right outer portion of the continuous strap  1 ′ outside the mold cavity  30 , so as to tension the continuous strap  1 ′, so that an inner portion of the continuous strap  1 ′ inside the mold cavity  30  can be fixed, which ensures the first injection molding portion  21   a  to be formed at a predetermined position and in a predetermined shape. In step S 3 , the end portion  10   a  of the strap  1   a  attached with the first injection molding portion  21   a  has a certain stiffness and hardness and therefore cannot be displaced or deformed easily when the end portion  10   a  of the strap  1   a  attached with the first injection molding portion  21   a  is placed in the mold cavity  40 , which prevents the end portion  10   a  of the strap  1   a  from moving out of a surface of the melted plastic material during injection of the plastic material, so as to ensure the end portion  10   a  of the strap  1   a  to be completely covered by the second injection molding portion  22   a.    
     Please refer to  FIG.  3    and  FIG.  4   .  FIG.  3    is a sectional diagram of an assembly P 2  formed by a plastic product  2   b  and a strap  2   b  according to a second embodiment of the present invention.  FIG.  4    is a sectional diagram illustrating a combining interface  20   b  of a first injection molding portion  21   b  and a second injection molding portion  22   b  of the plastic product  2  according to the second embodiment of the present invention. As shown in  FIG.  3    and  FIG.  4   , the assembly P 2  of this embodiment is similar to the assembly P 1  of the first embodiment, but the shapes of the first injection molding portion  21   b,  the second injection molding portion  22   b  and the combining interface  20   b  of the first injection molding portion  21  and the second injection molding portion  22   b  of this embodiment are different from the ones of the first embodiment. 
     Specifically, as shown in  FIG.  4   , in this embodiment, the combining interface  20   b  can include a flat surface structure perpendicular to a longitudinal direction of the strap  1   b,  i.e., parallel to the y-axis direction. 
     Please refer to  FIG.  5    and  FIG.  6   .  FIG.  5    is a sectional diagram of an assembly P 3  formed by a plastic product  2   c  and a strap  1   c  according to a third embodiment of the present invention.  FIG.  6    is a sectional diagram illustrating a combining interface  20   c  of a first injection molding portion  21   c  and a second injection molding portion  22   c  of the plastic product  2   c  according to the third embodiment of the present invention. As shown in  FIG.  5    and  FIG.  6   , the assembly P 3  of this embodiment is similar to the assembly P 1  of the first embodiment, but the shapes of the first injection molding portion  21   c,  the second injection molding portion  22   c  and the combining interface  20   c  of the first injection molding portion  21   c  and the second injection molding portion  22   c  of this embodiment are different from the ones of the first embodiment. 
     Specifically, as shown in  FIG.  6   , in this embodiment, the combining interface  20   b  can include a step-shaped structure which includes a first flat surface structure parallel to the longitudinal direction and coincided with a central axis of the strap  1   b,  and two second flat surface structures perpendicular to the longitudinal direction of the strap  1 , i.e., parallel to the y-axis direction, and connected to the flat surface structure. 
     Please refer to  FIG.  7    and  FIG.  8   .  FIG.  7    is a sectional diagram of an assembly P 4  formed by a plastic product  2   d  and a strap  1   d  according to a fourth embodiment of the present invention.  FIG.  8    is a sectional diagram illustrating a combining interface  20   d  of a first injection molding portion  21   d  and a second injection molding portion  22   d  of the plastic product  2   d  according to the fourth embodiment of the present invention. As shown in  FIG.  7    and  FIG.  8   , the assembly P 4  of this embodiment is similar to the assembly P 1  of the first embodiment, but the shapes of the first injection molding portion  21   d,  the second injection molding portion  22   d  and the combining interface  20   d  of the first injection molding portion  21   d  and the second injection molding portion  22   d  of this embodiment are different from the ones of the first embodiment. 
     Specifically, as shown in  FIG.  8   , in this embodiment, the combining interface  20   b  can include two flat surface structures perpendicular to the longitudinal direction of the strap  1   d,  i.e., parallel to the y-axis direction. 
     Please refer to  FIG.  9    and  FIG.  10   .  FIG.  9    is a sectional diagram of an assembly P 5  formed by a plastic product  2   e  and a strap  1   e  according to a fifth embodiment of the present invention.  FIG.  10    is a sectional diagram illustrating a combining interface  20   e  of a first injection molding portion  21   e  and a second injection molding portion  22   e  of the plastic product  2   e  according to the fifth embodiment of the present invention. As shown in  FIG.  9    and  FIG.  10   , the assembly P 5  of this embodiment is similar to the assembly P 1  of the first embodiment, but the shapes of the first injection molding portion  21   e,  the second injection molding portion  22   e  and the combining interface  20   e  of the first injection molding portion  21   e  and the second injection molding portion  22   e  of this embodiment are different from the ones of the first embodiment. 
     Specifically, as shown in  FIG.  10   , in this embodiment, the combining interface  20   b  can include two inflection surface structures symmetrical to each other, and each inflection surface structure can include two inclined surface structure inclined to the longitudinal direction of the strap  1   e,  i.e., the x-axis direction, and connected to each other. 
     The different combining interfaces can provide different combining areas. The greater combining area can achieve the greater combination strength. For example, the combining interface  20   a  of the first embodiment, the combining interface  20   c  of the third embodiment, the combining interface  20   e  of the fifth embodiment have greater combining areas and therefore achieve the greater combination strengths. Besides, inflection portions of the combining interface  20   a  of the first embodiment, the combining interface  20   c  of the third embodiment, the combining interface  20   e  of the fifth embodiment can achieve locking effects, which also facilitates to enhance the combination strengths of the first injection molding portions and the second injection molding portions. Since the combining interface  20   b  of the second embodiment and the combining interface  20   d  of the fourth embodiment include the flat surface structures, the first injection mold assemblies for manufacturing the first injection molding portions can have simple structure. 
     In contrast to the prior art, in the present invention, the plastic product is formed by the first injection molding portion and the second injection molding portion combined with the first injection molding portion. Furthermore, the length of the first injection molding portion along the longitudinal direction of the strap is less than the length of the plastic product along the longitudinal direction of the strap, and the protruding length of the end portion of the strap protruding out of the first injection molding portion is less than half of the thickness of the second injection molding portion along the radial direction of the strap perpendicular to the longitudinal direction of the strap. Therefore, the present invention can ensure the end portion of the strap to be completely covered by the first injection molding portion and the second injection molding portion and can solve a conventional problem that an end portion of a strap cannot be completely covered by a conventional plastic product. Besides, in the present invention, since the end portion of the strap is configured to protrude out of the first injection molding portion and completely be covered by the second injection molding portion, the end portion of the strap protruding out of the first injection molding portion and covered by the second injection molding portion can act as a fixing anchor, which not only enhances a combination strength of the first injection molding portion and the second injection molding portion but also enhances a combination strength of the plastic product and the strap. The present invention not only has a better aesthetic appearance and reduces a defect rate but also has enhanced combination strength for preventing the plastic product and the strap from separating from each other. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.