Abstract:
The present invention relates to a ring binder mechanism for binding the sheets of loose leaves. The mechanism comprises an elongated spring plate that extends longitudinally and, in profile, has a shallow U-shaped configuration and opposite edges which extend substantially toward each other; two parallel elongate hinge plates supported by said spring plate for pivotal toggle motion relative to the spring plate about a central hinge line, which are mounted in parallel and retained by the opposite edges of the spring plate; and a plurality of rings for clasping said sheets of loose leaves. Each of the rings comprises a pair of half ring elements of circular cross-section which are mounted on said hinge plates, with one half ring element of each pair being attached to one of the hinge plates and the other half ring element of the pair attached to the other hinge plate, with the two half ring elements of each pair in substantial alignment.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a ring binder mechanism for binding the sheets of loose leaves, especially to a binder mechanism with improved ring elements which can close tightly. 
   BACKGROUND OF THE INVENTION 
   A ring binder is applied to secure loose leaves, such as punched paper, into a file folder or a notebook. It is characterized by ring elements for securing paper, wherein the ring elements can be opened optionally to add or remove paper, or closed to secure paper, while allowing paper to move along them. Generally a lever is provided on both ends of the binder to move the ring elements between an opened position and a closed position. 
     FIGS. 20 and 21  show a ring binder according to the prior art. In the conventional ring binder, end faces  56  of half ring elements  54  form an engagement configuration with a convex portion and a concave portion. When the end faces  56  of the two half ring elements  54  close, the convex portion of the end face  56  of one half ring element engages with the concave portion of the end face  56  of the other half ring element. One disadvantage of this type of engagement configuration is that the end faces can not close tightly and align to each other exactly when two half ring elements close, so that vertical and transverse misalignments for the engagement configuration will occur, as illustrated in  FIGS. 20 and 21 . Owing to the disadvantage that the end faces  56  of the binder which engage with each other misalign up and down, paper which is bound by the binder can not be turned over smoothly, and can even be torn. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a ring binder mechanism that can overcome the above mentioned disadvantages of the prior art so as to enable the ring members to close tightly and align to each other exactly and eliminate the vertical and transverse misalignment. 
   This object is achieved according to the present invention by providing a ring binder mechanism for binding the sheets of loose leaves, the mechanism comprising: an elongated spring plate that extends longitudinally and, in profile, has a shallow U-shaped configuration and opposite edges which extend substantially toward each other; 
   two parallel elongate hinge plates supported by said spring plate for pivotal toggle motion relative to the spring plate about a central hinge line, the hinge plates being mounted in parallel and retained by the opposite edges of the spring plate; 
   a plurality of rings for clasping said sheets of loose leaves, each of the rings comprising a pair of half ring elements mounted on said hinge plates, with one half ring element of each pair being attached to one of the hinge plates and the other half ring element of the pair attached to the other hinge plate, with the two half ring elements of each pair in substantial alignment, the pairs of half ring elements being movable with said hinge plates to toggle between an open position and a closed position and forming a substantially annular shape when in the closed position; 
   wherein free ends of the half ring of each pair elements form a nesting configuration when in the closed position, the free end of one half ring element of each pair having a centrally concave nesting portion and the free end of the other half ring element of the pair having a centrally convex nesting portion, said concave portion and said convex portion being symmetrical about an axis line of the respective ring elements of the pair, so that when the pair of half ring elements are in the closed condition, the free ends of the half ring elements are aligned to each other, and form a surface-engagement, so that the convex resting portion and the concave nesting portion are nested together tightly. 
   Preferably, the nesting portion with a centrally convex portion is formed in a free end of one half ring element of said pair of half ring elements, and the nesting portion with a centrally concave portion is formed in a free end of the other engaging half ring element, the convex nesting portion has an annular conical surface, the concave nesting portion has a conical hole that is formed from its external end surface, a diameter of the conical hole on the external end surface is smaller than that of the cylindrical rod of the half ring element, a cone angle of the conical hole is smaller than that of the annular conical surface of the centrally protruding outwards nesting portion, when the half ring elements are in the closed condition, and the connecting portion between the external end surface of the concave nesting portion and the conical hole thereof engages with the annular conical surface of the convex nesting portion, so that the centrally convex nesting portion is nested in the centrally concave nesting portion. 
   Preferably, the nesting portion with a centrally convex portion is formed in a free end of one half ring element of said pair of half ring elements, and the nesting portion with a centrally concave portion is formed in a free end of the other engaging half ring element, the convex nesting portion has a protruding portion, the protruding portion is connected to a surface of the cylindrical rod of the half ring element via an annulus internal end surface, a diameter of the protruding portion on the internal end surface is smaller than that of the cylindrical rod of the half ring element, the concave nesting portion has a opening that is formed from its external end surface, a diameter of the opening on the external end surface is smaller than that of the cylindrical rod of the half ring element and slightly larger than that of the protruding portion on its internal end surface, when the half ring elements are in the closed condition, and the external end surface of the concave nesting portion and the internal end surface of convex nesting portion form a surface-engagement, so that the convex nesting portion is nested in the concave nesting portion. 
   Preferably, the protruding portion of the convex nesting portion has a conical shape, the opening of the concave nesting portion has a conical hole that is formed from its external end surface and an internal cylindrical hole that is connected to the conical hole. 
   Preferably, the protruding portion of the convex nesting portion has a shape that consists of a cylindrical tip and an arc-shaped annular conical base portion, and the opening of the concave nesting portion has a conical hole that is formed from its external end surface and an internal cylindrical hole that is connected to said conical hole. 
   Preferably, the protruding portion of the convex nesting portion has a cylindrical shape, the opening of the concave nesting portion has a shape of an internal cylindrical hole. 
   Preferably, the nesting portion with a centrally convex portion is formed in a free end of one half ring element of the pair of half ring element pairs, and the nesting portion with a centrally concave portion is formed in a free end of the other engaging half ring element, the convex nesting portion has a protruding conical portion, the conical portion is connected to a surface of the cylindrical rod of the half ring element via an annulus internal end surface, a diameter of the conical portion on the internal end surface is smaller than that of the cylindrical rod of the half ring element, the concave nesting portion has a conical hole that is formed from its external end surface, a diameter of the conical hole on the external end surface is smaller than that of the cylindrical rod of the half ring element and substantially equal to that of the protruding conical portion on the internal end surface, when the half ring elements are in the closed condition, the external end surface of the concave nesting portion and the internal end surface of the convex nesting portion form a surface-engagement, and the conical portion of the convex nesting portion and the conical hole of the concave nesting portion form an engagement, so that the concave nesting portion is nested in the convex nesting portion. 
   Preferably, the pair of half ring elements of the ring binder mechanism form a circular ring. 
   Preferably, one half ring element of said pair of half ring elements of the ring binder mechanism has a straight side. 
   Preferably, two, three, four or more rings are provided in the ring binder mechanism. 
   Preferably, the rings are made of metal material, and the metal material can be steel. 
   Preferably, the rings are made of plastic material. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top perspective view showing a ring binder mechanism in a closed condition according to one embodiment of the present invention. 
       FIG. 2  is a bottom perspective view showing the ring binder mechanism in  FIG. 1 . 
       FIG. 3  is a top perspective view showing the ring binder mechanism in  FIG. 1  in the opened condition. 
       FIG. 4  is a bottom perspective view showing the ring binder mechanism shown in  FIG. 3 . 
       FIG. 5  is a top exploded perspective view showing the ring binder mechanism in  FIG. 1 . 
       FIG. 6  are a front view, a side view and a back view showing the ring binder mechanism in  FIG. 1 . 
       FIG. 7  is a partial front view of the ring binder mechanism in  FIG. 1  in an opened and unclosed condition. 
       FIG. 8  is a partial front view showing a first embodiment of the ring elements of the ring binder mechanism in  FIG. 1  which is in a closed condition, and a partial enlarged view showing the nesting configuration in a closed condition. 
       FIG. 9  is a partial front view showing a second embodiment of the ring elements of the ring binder mechanism in  FIG. 1  that is in a closed condition, and a partial enlarged view showing the nesting configuration in a closed condition. 
       FIG. 10  is a partial front view showing a third embodiment of the ring elements of the ring binder mechanism in  FIG. 1  that is in a closed condition, and a partial enlarged view showing the nesting configuration in a closed condition. 
       FIG. 11  is a partial front view showing a fourth embodiment of the ring elements of the ring binder mechanism in  FIG. 1  that is in a closed condition, and a partial enlarged view showing the nesting configuration in a closed condition. 
       FIG. 12  is a partial front view showing a fifth embodiment of the ring elements of the ring binder mechanism in  FIG. 1  that is in a closed condition, and a partial enlarged view showing the nesting configuration in a closed condition. 
       FIG. 13  is a partial front view showing a sixth embodiment of the ring elements of the ring binder mechanism shown in  FIG. 1  that is in a closed condition, and a partial enlarged view showing the nesting configuration in a closed condition. 
       FIG. 14  is a top perspective view showing another ring binder mechanism in a closed condition according to the present invention, and a partial front view showing the ring element of the ring binder that is in a closed condition. 
       FIG. 15  is a top perspective view showing the ring binder mechanism in  FIG. 14  in an opened condition, and a partial front view showing this ring element of the ring binder that is in an opened condition. 
       FIG. 16  is a top perspective view showing still another ring binder mechanism in a closed condition according to the present invention, and a partial front view showing the ring element of this ring binder that is in a closed condition. 
       FIG. 17  is a top perspective view showing the ring binder mechanism in  FIG. 16  in an opened condition, and a partial front view showing the ring element of this ring binder that is in an opened condition. 
       FIG. 18  is a top perspective view showing still another ring binder mechanism in a closed condition according to the present invention, and a partial front view showing this ring element of this ring binder that is in a closed condition. 
       FIG. 19  is a top perspective view showing the ring binder mechanism in  FIG. 18  in an opened condition, and a partial front view showing the ring element of this ring binder that is in an opened condition. 
       FIGS. 20 and 21  are a perspective view and a partial enlarged perspective view, respectively, showing a ring binder of the prior art. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In all the above-mentioned figures, the corresponding parts are indicated by corresponding reference numbers. 
   Now referring to the above-mentioned figures, especially to the  FIGS. 1 ,  2  and  5 , the ring binder mechanism according to the present invention for binding the sheets of loose leaves is generally indicated by  30 . This mechanism includes an elongated plate  32  and three rings. The three rings are generally indicated by  34  and used to secure the sheets of loose leaves. 
   The plate  32  has a shape, viewed from the top or bottom, of an elongated rectangle and has a substantially arc-shaped (U-shaped) cross section with a rising portion thereof along its longitudinal direction. The plate  32 , as shown, has two ribs that extend along the longitudinal direction in the middle thereof. The plate  32  has two substantially opposite longitudinal edges  40  and substantially opposite transverse ends. A bent bottom edge  44  is formed each along both of the longitudinal edges  40  ( FIG. 2 ). The opposite longitudinal edges are therefore directed toward each other. The plate  32  can be configured in profile as an upside down “U” as shown. The elongated plate  32  is made of metal or any other suitable material which has enough rigidity and can provide a stable attachment for other parts of the mechanism, while light-weight, material-saving and cost-saving. Two holes  46  are provided in the plate  32  ( FIG. 5 ) for receiving and attaching a bushing  48  respectively, so that the mechanism can be fastened in a file folder of a notebook. Six additional holes  52  are positioned along the longitudinal edges  40  for receiving a ring that passes therethrough respectively. Those plates or shells that have other kinds of shapes, including irregular shapes, or those mechanisms that are formed in a file folder or a notebook integrally, all fall within the scope of the present invention. 
   Each of the three rings  34  comprises two half ring elements  54  that can move between a closed position ( FIGS. 1 and 2 ) and an opened position ( FIGS. 3 and 4 ), in which in the closed position each of the ring element forms a continuously closed ring for securing sheets of loose leaves, and in the opened position each of the ring element forms a discontinuously opened ring for adding or removing sheets of loose leaves. The ring element  54  is formed by a substantially cylindrical rod that is made of a suitable material, such as steel. Although in the embodiment shown the two half ring elements  54  of each of the three rings  34  are both movable, a mechanism that has one movable half ring element and one fixed half ring element also falls into the scope of the present invention. Furthermore, those kinds of mechanism which have various numbers, such as more than or less than three rings all fall into the scope of the present invention. 
   The half ring elements  54  are provided on hinge plates  56  that are supported by the elongated plate  32  ( FIGS. 2 and 4 ). The hinge plates  56  are provided for a pivotable movement, so as to move the ring elements between the closed position and the opened position. The hinge plates  56  are provided in parallel for attachment and connected in parallel to each other, so that they can pivotably rotate along the adjacent longitudinal edges. Slots  60  are provided in the hinge plates  56  for connecting to the ring elements. Each of the hinge plates  56  has an outer longitudinal edge  62  that is opposite to a fold line ( FIG. 5 ). The longitudinal edges  62  are inserted into the corresponding bent bottom edges  44  of the elongated plate  32  respectively. The longitudinal edges  62  can move freely in the edges  44  respectively, so as to make the interconnected hinge plates  56  pivotably rotate. The elongated plate  32  provides a small elastic force to press the hinge plates  56  offset away from a common surface position (that is, to face towards the closed position or the opened position). A special control means that is generally indicated by  38  is provided for pivot rotating the hinge plates  56  in a controllable way, so as to move the ring elements between the closed position and the opened position.  FIG. 6  shows the ring binder mechanism shown in  FIG. 1  via a front view, a side view and a back view respectively. 
   The ring elements of the ring binder mechanism according to the present invention will be further described as follows: 
     FIGS. 7 and 8  show a first embodiment of nesting portions  156 ,  156 ′ of the ring element of the ring binder mechanism according to the present invention. As shown in the  FIG. 8  that is a partial enlarged view, the nesting portions  156 ,  156 ′ that are in the closed condition have a central axis line  51 . The nesting portion  156  with a centrally convex portion along the axis line  51  is formed in a free end of one half ring element  54 . A cylindrical tip  150  whose diameter is smaller than that of the cylindrical rod of the half ring element  54  is formed on the top portion of the nesting portion  156  around the axis line  51 . The tip  150  is connected to a surface of the cylindrical rod of the half ring element  54  via an annulus conical surface  151 . The nesting portion  156 ′ with centrally concave portion along the axis line  51  is formed in a free end of the other engaging half ring element  54 . The nesting portion  156 ′ substantially forms a cylindrical hole  152  around the axis line  51 . The cylindrical hole  152  has a conical portion in its bottom. The diameter of the cylindrical hole  152  is larger than that of the top cylinder portion of the nesting portion  156 , but smaller than that of the cylindrical rod of the half ring element  54 . By a conical hole  153  that tapers outwards, the cylindrical hole  152  is connected to an external end surface  154 ′ of the nesting portion  156 ′ at a position adjacent to an external surface of the cylindrical pole. A diameter of the conical hole  153  on the external end surface  154 ′ is slightly smaller than that of the cylindrical rod of the half ring element  54 . A cone angle of the conical hole of the centrally concave nesting portion  156 ′ relative to the axis ling  51  is smaller than that of the annular conical surface of the centrally convex nesting portion  156 . When the half ring elements  54  are in the closed condition, as shown in  FIG. 8 , the connecting portion between the external end surface  154 ′ of the concave nesting portion  156 ′ and the conical hole  153  engages with the annular conical surface  151  of the convex nesting portion  156 , so that the centrally convex nesting portion  156  of the half ring elements  54  is nested in the centrally concave nesting portion  156 ′ of the corresponding half ring elements  54 . In this way, the engagement between the two nesting portions is tighter and the problem that the nesting portions are misaligned can be avoided. 
     FIG. 9  shows a second embodiment of nesting portions  256 ,  256 ′ of the ring element of the ring binder mechanism according to the present invention. As shown in the  FIG. 9  that is a partial enlarged view, the nesting portions  256 ,  256 ′ that are in the closed condition have a central axis line  51 . The nesting portion  256  with centrally convex portion along the axis line  51  is formed in a free end of one half ring element  54 . A cylindrical tip  150  whose diameter is smaller than that of the cylindrical rod of the half ring element  54  is formed on the top portion of the nesting portion  256  around the axis line  51 . The tip  150  is connected to a position of an internal end surface  154  of the nesting portion  256  that is adjacent to an external surface of the cylindrical rod of the half ring element  54  via an arc-shaped annulus conical surface  151 . The nesting portion  256 ′ with a centrally concave portion along the axis line  51  is formed in a free end of the other engaging half ring element  54 . The concave nesting portion  256 ′ substantially forms a cylindrical hole  152  around the axis line  51 . The cylindrical hole  152  has a conical portion in its bottom. The diameter of the cylindrical hole  152  is larger than that of the top cylinder portion of the convex nesting portion  256 , but smaller than that of the cylindrical rod of the half ring element  54 . By a conical hole  153  that tapers outwards, the cylindrical hole  152  is connected to the external end surface  154 ′ of the nesting portion  256 ′ at a position adjacent to an external surface of the cylindrical pole. A cone angle of the conical hole of the centrally concave nesting portion  256 ′ relative to the axis ling  51  is smaller than that of the annular conical surface of the centrally convex nesting portion  256 . A diameter of the conical hole  153  on the external end surface  154 ′ is slightly larger than that of the annulus conical surface on the internal end surface  154 . When the half ring elements  54  are in the closed condition, as shown in  FIG. 9 , the external end surface  154 ′ of the concave nesting portion  256 ′ and the internal end surface  154  of convex nesting portion  256  form a tight surface-engagement, so that the centrally convex nesting portion  256  of the half ring elements  54  is nested in the centrally concave nesting portion  256 ′ of the corresponding half ring elements  54 . In this way, the engagement between the two nesting portions is tighter and the problem that the nesting portions are misaligned can be avoided. 
     FIG. 10  shows a third embodiment of nesting portions  356 ,  356 ′ of the ring element of the ring binder mechanism according to the present invention. The configuration of the third embodiment is substantially similar to that of the nesting portion shown in  FIG. 9 . The differences is in that: instead of the cylindrical tip and the an arc-shaped annulus conical surface shown in  FIG. 9 , an arc-shaped conical surface  151  is formed on the top portion of the convex nesting portion  356  around the axis line  51 . In this way, the risk that paper is torn by the sharp edges of the nesting portions when the paper is added or removed can be eliminated. 
     FIG. 11  shows a fourth embodiment of nesting portions  456 ,  456 ′ of the ring element of the ring binder mechanism according to the present invention. As shown in the  FIG. 11  that is a partial enlarged view, the nesting portions  456 ,  456 ′ that are in the closed condition have a central axis line  51 . The nesting portion  456  with centrally convex portion along the axis line  51  is formed in a free end of one half ring element  54 . A cylindrical tip  150  whose diameter is smaller than that of the cylindrical rod of the half ring element  54  is formed on the top portion of the convex nesting portion  456  around the axis line  51 . The tip  150  is connected to a surface of the cylindrical rod of the half ring element  54  via an internal end surface  154  of the convex nesting portion  456 . The nesting portion  456 ′ with centrally concave along the axis line  51  is formed in a free end of the other engaging half ring element  54 . The concave nesting portion  456 ′ substantially forms a cylindrical hole  152  around the axis line  51 . The cylindrical hole  152  has a conical portion in its bottom. The diameter of the cylindrical hole  152  is larger than that of the tip  150  of the nesting portion  456 , but smaller than that of the cylindrical rod of the half ring element  54 . The cylindrical hole  152  is connected to an external surface of the cylindrical rod via an external end surface  154 ′ of the concave nesting portion  456 ′. When the half ring elements  54  are in the closed condition, as shown in  FIG. 11 , the external end surface  154 ′ of the concave nesting portion  456 ′ and the internal end surface  154  of convex nesting portion  456  form a tight surface-engagement, so that the centrally convex nesting portion  456  of the half ring elements  54  is nested in the centrally concave nesting portion  456 ′ of the corresponding half ring elements  54 . In this way, the engagement between the two nesting portions is tighter and the problem that the nesting portions are misaligned can be avoided. 
     FIG. 12  shows a fifth embodiment of nesting portions  556 ,  556 ′ of the ring element of the ring binder mechanism according to the present invention. As shown in the  FIG. 12  that is a partial enlarged view, the nesting portions  556 ,  556 ′ that are in the closed condition have a central axis line  51 . The nesting portion  556  with centrally convex portion along the axis line  51  is formed in a free end of one half ring element  54 . A flat top frusto-conical portion  150  is formed on the top portion of the convex nesting portion  556  around the axis line  51 . The flat top frusto-conical portion  150  is connected to a surface of the cylindrical rod of the half ring element  54  via an internal end surface  154  of the convex nesting portion  556 . The nesting portion  556 ′ with centrally concave portion along the axis line  51  is formed in a free end of the other engaging half ring element  54 . The concave nesting portion  556 ′ substantially forms a flat bottom frusto-conical hole  152  around the axis line  51 . The frusto-conical hole  152  is connected to an external surface of the cylindrical rod via an external end surface  154 ′ of the concave nesting portion  556 ′. A cone angle of the frusto-conical hole of the centrally concave nesting portion  556 ′ relative to the axis ling  51  is substantially equal to that of the flat top frusto-conical portion  150  of the centrally convex nesting portion  556 , and a diameter of the flat bottom frusto-conical hole  152  on the external end surface  154 ′ is slightly equal to that of the flat top frusto-conical portion  150  on the internal end surface  154 . When the half ring elements  54  are in the closed condition, as shown in  FIG. 12 , the external end surface  154 ′ of the concave nesting portion  556 ′ and the internal end surface  154  of convex nesting portion  556  form a tight surface-engagement, so that the centrally convex nesting portion  556  of the half ring elements  54  is nested in the centrally concave nesting portion  556 ′ of the corresponding half ring elements  54 . In this way, the engagement between the two nesting portions is tighter and the problem that the nesting portions are misaligned can be avoided. 
     FIG. 13  shows a sixth embodiment of nesting portions  656 ,  656 ′ of the ring element of the ring binder mechanism according to the present invention. The configuration of the sixth embodiment is substantially similar to that of the nesting portion shown in  FIG. 12 . The difference is in that: the flat top frusto-conical portion of the nesting portion  556  shown in  FIG. 11  is replaced with an arc-shaped top frusto-conical portion shown in  FIG. 13 . In this way, the risk that paper is torn by the sharp edges of the nesting portions when the paper is added or removed can be eliminated. 
     FIGS. 14 and 15  show another ring binder mechanism according to the present invention that is in a closed condition. The mechanism comprises two rings. One of the half ring elements of each of said rings has a straight side. The nesting portions of the ring elements of the ring binder mechanism also can have the configuration of the above mentioned first to sixth embodiments shown in  FIGS. 7 to 13 . 
     FIGS. 16 and 17  show another ring binder mechanism according to the present invention that is in a closed condition and an opened condition, respectively. The mechanism comprises four rings. One of the half ring elements of each of said rings has a straight side, similar to  FIGS. 14 and 15 . The nesting portions of the ring elements of the ring binder mechanism also can have the configuration of the above mentioned first to sixth embodiments shown in  FIGS. 7 to 13 . In addition, those kinds of mechanism which have various numbers, such as more than or less than four rings are all fell into the scope of the present invention. 
     FIGS. 18 and 19  show another ring binder mechanism according to the present invention that is in a closed condition and an opened condition, respectively. The mechanism comprises three rings. One of the half ring elements of each of said rings has an inclined straight side. The nesting portions of the ring elements of the ring binder mechanism also can have the configuration of the above mentioned first to sixth embodiments shown in  FIGS. 7 to 13 . In addition, those kinds of mechanism which have various numbers, such as more than or less than three rings, all fall into the scope of the present invention. 
   Because various modifications can be done without departing from the scope of the present invention, it should be understood that all the content that is included in the above description and are shown in the figures is only instructive, while not limiting the scope of the invention.