Abstract:
To solve a tilting of a button in electronic information devices, there is provided a button assembly comprising: a housing with a guide surface formed inside thereof and extending along a direction; a button shaft slidably inserted into the guide surface, and comprising a first recess formed in an outer circumferential surface thereof; a washer inserted into the first recess, and preventing an outward ejection of the button shaft in the guide surface; and an elastic member that biases the button shaft outward, wherein the button shaft comprises a second recess formed adjacent to the first recess and a method of manufacturing a button shaft for a button assembly.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2009-0102283, filed on Oct. 27, 2009, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
       BACKGROUND 
       [0002]    Embodiments of the present invention relate to a button assembly and a method of manufacturing a button shaft for a button assembly. 
         [0003]    Button assemblies include buttons and are used in various kinds of electronic information appliances, such as digital cameras, camcorders, MP3 players, portable multimedia players (PMPs), and the like. When a user presses a button of a button assembly and then releases the button, the button returns to its original position. For this configuration, a button assembly includes an elastic member that biases a button upward, and a washer that prevents the button from ejecting upward. 
       SUMMARY 
       [0004]    According to an embodiment of the invention, there is provided a button assembly comprising: a housing with a guide surface formed inside thereof and extending along a direction; a button shaft slidably inserted into the guide surface, and comprising a first recess formed in an outer circumferential surface thereof; a washer inserted into the first recess that prevents an outward ejection of the button shaft in the guide surface; and an elastic member that biases the button shaft outward, wherein the button shaft comprises a second recess formed adjacent to the first recess. 
         [0005]    Although a cleavage is formed at the contact surface between a sliding core and a lower mold, a recess for a washer formed in a button shaft does not have a burr. Thus, a tilting of a button may be prevented, and the quality of image photographing devices, such as cameras may be enhanced. 
         [0006]    The first recess and the second recess may be parallel to each other and respectively formed in the outer circumferential surface of the button shaft. 
         [0007]    The first recess and the second recess need not be spaced apart from each other in a longitudinal direction of the button shaft. A depth of the first recess may be smaller than a depth of the second recess. 
         [0008]    The first recess and the second recess may be spaced apart from each other in a longitudinal direction of the button shaft. In this regard, a depth of the first recess may be the same as or different from a depth of the second recess. 
         [0009]    The button assembly may further comprise a button head coupled to a top portion of the button shaft, wherein the elastic member comprises a conical coil spring positioned between the button head and the housing. 
         [0010]    The washer may be in a shape of a doughnut, a part of which is cut, and cut portions of the washer are displaced with respect to each other so as to be inserted into the button shaft. 
         [0011]    The button assembly may be used as a release button for an image photographing device, but is not limited thereto. 
         [0012]    According to another aspect of the present invention, there is provided a method of manufacturing a button shaft for a button assembly by forming a recess for a washer in the button shaft movably inserted into an internal guide surface of a housing, the method comprising: arranging a lower mold and a sliding core to be used to perform injection molding of the button shaft; injecting a raw material into the lower mold and the sliding core; and moving the sliding core in a radial direction from a center of the button shaft, wherein a parting line corresponding to a contact surface between the lower mold and the sliding core is formed at a height different from a height of a bottom surface of the recess for a washer into which the washer is inserted. 
         [0013]    The button shaft may be made of a material comprising polycarbonate (PC). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: 
           [0015]      FIG. 1  is a side cross-sectional view of a button assembly according to an embodiment of the present invention; 
           [0016]      FIG. 2  is a perspective view illustrating coupling between a button part and a washer in the button assembly of  FIG. 1 ; 
           [0017]      FIG. 3  is a side cross-sectional view of a button assembly according to another embodiment of the present invention; 
           [0018]      FIGS. 4A through 4C  are side cross-sectional views illustrating a method of manufacturing a button shaft for an image photographing device, according to an embodiment of the present invention; 
           [0019]      FIG. 5  is an enlarged side cross-sectional view of a region represented by a dashed double-dotted line of  FIG. 4B , according to an embodiment of the present invention; and 
           [0020]      FIG. 6  is an enlarged side cross-sectional view illustrating a portion of a manufactured button shaft for an image photographing device corresponding to the region of  FIG. 5 , according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. 
         [0022]      FIG. 1  is a side cross-sectional view of a button assembly according to an embodiment of the present invention.  FIG. 2  is a view illustrating coupling between a button part and a washer in the button assembly of  FIG. 1 . Referring to  FIGS. 1 and 2 , the button assembly includes a button part  10 , a housing  21 , a washer  40 , and an elastic member  30 . The button part  10  includes a button shaft  11  and a button head  12 . The button shaft  11  is slidably inserted into a guide surface  21   a  of the housing  21 . The elastic member  30 , for example, a conical coil spring, is inserted between the button head  12  of the button part  10  and an internal surface of the housing  21 , so that the button part  10  is biased outward, that is, in an external direction of a digital image photographing device including the button assembly. The button shaft  11  includes a recess  11   a  for a washer, and the washer  40  is inserted into the recess  11   a . The washer  40  prevents the button part  10  from ejecting outward. When the button part  10  is pressed inward by a user and then released, the button part  10  returns to its original position by cooperative operation of the elastic member  30  and the washer  40 . 
         [0023]    The recess  11   a  includes a first recess  11   aa  and a second recess  11   ab  that are adjacent to each other. The term “adjacent to each other” as used herein may be understood to include that as illustrated in  FIG. 1 , wherein the first and second recesses  11   aa  and  11   ab  contact each other, and as illustrated in  FIG. 3 , wherein first and second recesses  111   aa  and  111   ab  are spaced apart from each other at a constant distance in a longitudinal direction of a button shaft  111 —however, this term is not limited to the exemplary embodiments illustrated, and should be construed according to its plain and ordinary meaning. 
         [0024]    The first and second recesses  11   aa  and  11   ab  are respectively formed in an outer circumferential surface of the button shaft  11 , and are parallel to each other. The depth of the first recess  11   aa  may be different from the depth of the second recess  11   ab , as illustrated in  FIG. 1 . As illustrated in  FIG. 3 , the depth of the first recess  11   aa  may be the same as the depth of the second recess  11   ab . The first recess  11   aa  is not spaced apart from the second recess  11   ab , as illustrated in  FIG. 1 , and the depth of the first recess  11   aa  needs to be greater than the depth of the second recess  11   ab . On the other hand, the first recess  111   aa  is spaced apart from the second recess  111   ab  as illustrated in  FIG. 3 , and the depths of the first and second recesses  111   aa  and  111   ab  do not matter. 
         [0025]    The first recess  11   aa  or  111   aa  and the second recess  11   ab  or  111   ab  of the recess  11   a  or  111   a , respectively, are formed so that a contact surface between the washer  40  and the recess  11   a  or  111   a  is not formed in a position corresponding to a parting line P ( FIG. 4B ) that corresponds to an interface between a sliding core  60  ( FIG. 4B ) and a lower mold, which will later be described. Embodiments of the recess  11   a , including the first and second recesses  11   aa  and  11   ab , and the recess  111   a , including the first and second recesses  111   aa  and  111   ab , are illustrated in  FIGS. 1 and 3 , but are not limited thereto. In other words, the recess  11   a  may be any recess for a washer with a shape that allows a bottom surface of the recess  11   a , which contacts the washer  40 , not to be formed in a position corresponding to the parting line P. 
         [0026]    The button shaft  11  and the button head  12  of the button part  10  may be made of different materials. For example, the button shaft  11  may be made of polycarbonate (PC), and the button head  12  may be made of a plated acrylonitrile-butadiene-styrene (ABS) plastic. When the button part  10  is made of two different kinds of plastics, the button part  10  may be prepared by double injection molding. However, the button part  10  is not limited thereto, and the button part  10  may be made of the same material. 
         [0027]    The button assembly may be used as a release button in image photographing devices, such as digital cameras or camcorders. Thus, an appearance of the button assembly may be enhanced by plating the button head  12  of the button part  10  with a metal, such as chrome or nickel. 
         [0028]    The elastic member  30  is illustrated in  FIGS. 1 and 3  as a conical coil spring, but is not limited thereto. The elastic member  30  may be any elastic member that provides the button shaft  11  with an elastic force capable of biasing the button shaft  11  outward. 
         [0029]    The washer  40  is in a shape of a doughnut, a part of which is cut. In other words, the washer  40  may in the form of a C-ring. The inside diameter of the washer  40  may be greater than or the same as that of the first recess  11   aa , and may be smaller than the diameter of the button shaft  11 . Thus, when a user holds cut portions  40   a  of the washer  40 , twists the cut portions  40   a  in opposite directions to each other, and then inserts the washer  40  into the button shaft  11 , the shape of the washer  40  returns to its original shape by a resilient force. 
         [0030]      FIGS. 4A through 4C  are views illustrating a method of manufacturing a button shaft for an image photographing device, according to an embodiment of the present invention. 
         [0031]    First, a lower mold  70  and a sliding core  60  are arranged (refer to  FIG. 4A ). The lower mold  70  and the sliding core  60  are used to perform injection molding of the button shaft  11 . The lower mold  70  and the sliding core  60  are disposed to about on each other, and the contact surface between the lower mold  70  and the sliding core  60  defines the parting line P. For convenience for illustration, an upper mold is not illustrated herein. 
         [0032]    A melted plastic is injected into a space formed in the sliding core  60  and the lower mold  70  (refer to  FIG. 4B ). Although not illustrated in  FIG. 4B , the button head  12  of the button part  10  may be formed in a space formed in the upper mold (not shown) and the sliding core  60 . When the button head  12  is formed of a material different from that of the button shaft  11 , the button part  10  may be prepared by double injection molding. 
         [0033]    After the injection of the melted plastic, the sliding core  60  is removed to form the button shaft  11  including the recess  11   a  (refer to  FIG. 4C ). 
         [0034]      FIG. 5  is an enlarged view of a region represented by a dashed double-dotted line of  FIG. 4B , according to an embodiment of the present invention.  FIG. 6  is a view illustrating a portion of a manufactured button shaft for an image photographing device the portion corresponding to the region of  FIG. 5 , according to an embodiment of the present invention. Referring to  FIG. 5 , the sliding core  60  has a surface recessed at the parting line P. As illustrated in  FIG. 5 , due to repetitive injection molding, a cleavage C may be formed at the contact surface between the sliding core  60  and the lower mold  70  in which the interface between the sliding core  60  and the lower mold  70  is supposed to be smoothly formed corresponding to the parting line P. In other words, the mold structure may be defective. As illustrated in  FIG. 6 , the button shaft has a burr b corresponding to the parting line P. In particular, when a surface of a recess in which the washer  40  is inserted thereto is formed has the burr b, the inserted washer  40  is tilted, and thus the appearance of the button assembly is defective. In addition, the cleavage C between the sliding core  60  and the lower mold  70  grows bigger with time passing by, and thus the defective appearance of the button part  10  caused by the burr b is more serious. 
         [0035]    Referring to  FIG. 4B , a bottom surface of the first recess  11   aa  of the button shaft  11  into which the washer  40  is inserted is formed above the parting line P. That is, in the injection molding, the recess  11   a  includes the first recess  11   aa  and the second recess  11   ab  formed adjacent to the first recess  11   aa  so that the bottom surface of the first recess  11   aa  of the button shaft  11  into which the washer  40  is inserted is not positioned at a height corresponding to the parting line P. A bottom surface of the second recess  11   ab  is positioned at a height corresponding to the parting line P. In this regard, the washer  40  is not inserted into the second recess  11   ab , and thus, although the bottom surface of the second recess  11   ab  has the burr b, the washer  40  is not tilted. Since the recess  11   a  of the button shaft  11  does not have the burr b, although the cleavage C may be formed at the contact surface between the sliding core  60  and the lower mold  70  due to repetitive injection molding, the productivity the button assembly may increase and the quality of image photographing devices may be enhanced. 
         [0036]    For example, a button assembly according to one or more embodiments of the present invention may be used in image photographing devices and various kinds of electronic information devices. In addition, a button shaft of the button assembly may be prepared by die casting using at least two molds. 
         [0037]    All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
         [0038]    For the purposes of promoting an understanding of the principles of the invention, reference has been made to the preferred embodiments illustrated in the drawings, and specific language has been used to describe these embodiments. However, no limitation of the scope of the invention is intended by this specific language, and the invention should be construed to encompass all embodiments that would normally occur to one of ordinary skill in the art. 
         [0039]    The present invention may be described in terms of functional block components and various processing steps. Such functional blocks may be realized by any number of components configured to perform the specified functions. The particular implementations shown and described herein are illustrative examples of the invention and are not intended to otherwise limit the scope of the invention in any way. For the sake of brevity, conventional aspects may not be described in detail. Furthermore, the connecting lines, or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections or logical connections may be present in a practical device. Moreover, no item or component is essential to the practice of the invention unless the element is specifically described as “essential” or “critical”. 
         [0040]    The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
         [0041]    The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural. Finally, the steps of all methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. 
         [0042]    The words “mechanism” and “element” are intended to be used generally and are not limited solely to mechanical embodiments. Numerous modifications and adaptations will be readily apparent to those skilled in this art without departing from the spirit and scope of the present invention.