Abstract:
A hinge damper is comprised of a rotation axis that is rotated according to the rotation of a rotation member and is pivotally attached to a case to be able to rotate freely, a gearing that is attached to the rotation axis to be able to freely rotate while having an internal tooth, means for transferring the rotation of the open/close member to the gearing, a gear planet that is engaged with the internal tooth of the gearing, rotation control means that regulates the rotation of the gear planet so that its center performs circular locus movement around the rotation center of the gearing, and means that absorbs the rotation energy of the gearing.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a hinge damper of an opening/closing device that enables smooth and safe opening/closing of an opening/closing member of a document pressing plate of a copier or an opening/closing member of a toilet seat.  
         [0003]     2. Related Art  
         [0004]     Conventionally, in an opening/closing device of a document pressing plate that includes an attachment member that is attached to an apparatus body such as a copier, a support member that can freely rotate and support the document pressing plate while being pivotally attached to the attachment member, and a compressed coil spring that is inserted between the attachment member and the support member while biasing the document pressing plate to the opening direction thereof, there is a technique that prevents the document pressing plate from suddenly falling because the weight of the document pressing plate overcomes the bias of the pressed coil spring and resultingly prevents a hand of the user from being caught between the plate and the apparatus body or the position of the document being moved (for example, refer to Patent Document 1).  
         [0005]     However, the above-mentioned conventional technique to prevent the document pressing plate from sudden falling uses an oil damper and therefore has the following problems: 
    1. As the damper absorbs energy in the loading direction, rigidity is required for the case that receives a piston;     2. Since it is made of metal such as die-cast, the damper is heavy. In addition, since it becomes long in its axial direction, the damper requires space for installation;     3. To put it in a coil spring in a hinge, the spring itself is large-sized;     4. Since the oil viscosity resistance is converted into heat energy, it comes to possess high temperature when used continuously. Moreover, since the oil viscosity resistance depends on the outside temperature, it is unstable. Therefore, there may be cases where the damper does not function well when the opening/closing device is opened and closed in succession;     5. If the document pressing device is closed forcibly, overload is applied to the damper to raise the oil pressure inside thereof, which may lead to a damage;     6. Since the piston rod of the damper is prone to eccentric loading, it must be operated with high accuracy and may easily cause oil leakage and/or breakage of the device;     7. Oil or water around the damper may adhere on the piston rod, causing damage to a packing or malfunctioning;     8. When disposed, it requires an environmental measure due to oil or the like, and;     9. Since the oil depends on the outside temperature, when used in a location that is not kept in room temperature, performance of the damper differs significantly. 
 
 Patent Reference 1: Japanese Utility Model Publication No. 2589714 
   
 
         [0015]     The purpose of the present invention is to provide a hinge damper of an opening/closing device that can solve the above mentioned problems and is light weight, small, stable even when used for a long period of time, and easy to perform maintenance.  
       SUMMARY OF THE INVENTION  
       [0016]     A hinge damper of the present invention includes an attachment member to be attached to an apparatus body such as a copier, a support member that can freely rotate and support a open/close member such as a document pressing plate while being pivotally attached to the attachment member, a compressed coil spring that is inserted between the attachment member and the support member while biasing the open/close member toward its opening direction, and an elastic body such as urethane elastomer foam, wherein a rotation axis that is rotated according to the rotation of a rotation member and is pivotally attached to a case to be able to rotate, a gearing that is attached to the rotation axis while having internal teeth, means for transferring the rotation of the open/close member to the gearing, a gear planet that is engaged with the internal teeth of the gearing, rotation control means that regulates the rotation of the gear planet so that its center performs circular locus movement around the rotation center of the gearing, and means that absorb the rotation energy of the gearing are included. In addition, the means that transfers the rotation of the open/close member to the gearing is a sector gear. Moreover, the means that regulates the rotation of the gear planet has an actuation pin that is implanted in the gear planet and a bush that has a hole to which the actuation pin is inserted so that the action of the pin is regulated. Furthermore, the means to absorb the rotation energy of the gearing has a friction tooth formed on the gearing and a plate planet having wave-shape periphery surface on which the friction tooth slides. Still furthermore, the hinge damper is incorporated into the attachment member of the open/close member.  
         [0017]     The hinge damper of the present invention has following advantages; it has a large capacity to absorb energy thanks to the structure of a small damper function, is light weight and small, stable when used for a long period of time, and is easy to perform maintenance. Moreover, there is another advantage that as it does not use oil like conventional oil dampers, problems mentioned above can be avoided. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1A  is a side-view of an opening/closing device of a document pressing plate having a hinge damper of the present invention and  1 B is a view showing its function.  
         [0019]      FIG. 2  is an external view of the hinge damper.  
         [0020]      FIG. 3  is a perspective view of a hinge damper that is disassembled in a support axis direction.  
         [0021]      FIG. 4  is a cross sectional view of the hinge damper.  
         [0022]      FIG. 5  is a cross sectional view taken along a line A-A of  FIG. 4 .  
         [0023]      FIG. 6  is a cross sectional view taken along a line B-B of  FIG. 4 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     Hereinafter, an embodiment of a hinge damper of an opening/closing device of the present invention will be described referring to figures.  
         [0025]     In  FIG. 1 , P is a document pressing plate which is attached to M, a main body of a copier or the like, via an H, which is an opening/closing device. P can open/close freely. The opening/closing device H mainly includes an attachment member  1  which is attached to the main body M, a support arm  3  which is pivotally attached to the attachment member  1  via a hinge axis  2  so as to allow the support arm  3  to freely move in a rotational manner, and a lift arm  5  which is pivotally attached to a tip of the support arm  3  via a support axis  4  so as to allow the lift arm  5  to freely move in a rotational manner.  
         [0026]     In the support arm  3 , a first slider  6  and a second slider  7  are installed while enabling them to freely slide in a longitudinal direction. Between the first and second sliders  6  and  7 , a compressed coil spring  8  is inserted. Instead of the compressed coil spring  8 , an urethane elastomer foam may be used. A cam follower  6   a  of the first slider  6  is attached to a cam part  9  placed on the attachment member  1 , while a cam follower  7   a  of the second slider  7  is attached to a front side plate  5   a  of the lift arm  5 . Note that the opening/closing device H of the present invention is not limited to the structure described above and any conventional structure, for example, one in which the support axis  4  and the lift arm  5  are not included and the document pressing plate P is attached and fixed to the support arm  3 , may be used.  
         [0027]     In the attachment member  1  which is in the vicinity of the hinge axis  2 , a case  10  of the hinge damper is provided.  
         [0028]      FIG. 2  shows external appearance of the case  10  of the hinge damper and the case  10  includes a case body  10   a  and a lid  10   b .  11  is an attachment frame for attaching the case  10  to the opening/closing device H. In the case  10 , as shown in  FIG. 3  which is an exploded diagram, a hinge damper is installed.  
         [0029]     In  FIG. 3, 12  is a sector gear,  13  is a small gear,  14  is a support axis,  15  is a first internal tooth gear,  16  is a first gear planet,  17   a  is a first eccentric shaft,  17   b  is a second eccentric shaft,  18  is a second internal tooth gear,  19  is a second gear planet,  20  is a third internal tooth gear,  21  is a third gear planet,  22   a  is a third eccentric shaft,  22   b  is a fourth eccentric shaft,  23  is a fourth internal tooth gear, and  24  is a fourth gear planet.  
         [0030]     As apparent from  FIG. 5 , the sector gear  12  is attached and fixed to the hinge axis  2  of the opening/closing device H and rotates along with the rotation of the hinge axis  2 . On the sector gear  12 , along the rotation angle thereof that is almost equal to the rotation angle of the opening/closing device H, teeth  12   a  are formed.  
         [0031]     The small gear  13  is attached to freely rotate around the support axis  14  and is engaged with the sector gear  12 . A flange portion  13   a  is provided to the small gear  13  in an integrated manner. The flange portion  13   a  has a plain part  13   a ′. On the tip of the support axis  14 , a square-headed bolt  14   a  is provided and is fitted into a square hole  11   a  of the attachment frame  11  to prevent it from rotating.  
         [0032]     As apparent from  FIG. 5 , the flange portion  13   a  of the small gear  13  is fitted into a hole  15   a  formed on the first internal tooth gear  15  and a plain part  15   a ′ thereof is attached to the plain part  13   a ′ of the flange portion  13  so that they are rotated in an integrated manner.  
         [0033]     As shown in  FIG. 6 , teeth  16   a  of the first gear planet  16  is engaged with teeth  15   a  of the first internal tooth gear  15  and can roll. The first gear planet  16  is attached to the first eccentric shaft  17   a  and can freely rotate. The first eccentric shaft  17   a  is attached to the support axis  14  and cannot rotate. Therefore, the first gear planet  16  rotates in a condition where it is decentered to the central axis of the support axis  14 .  
         [0034]     As apparent from  FIG. 4 , the second internal tooth gear  18  is connected to the first gear planet  16  so that they rotate in an integrated manner. The second internal tooth gear  18  is engaged with the second gear planet  19  so that they rotate in an integrated manner. The second gear planet  19  is attached so that it rotates in a condition where it is decentered to the second eccentric shaft  17   b . The first eccentric shaft  17   a  and the second eccentric shaft  17   b  are located to be symmetric to the central axis of the support axis  14 .  
         [0035]     The third internal tooth gear  20  is connected to the second gear planet  19  so that they can rotate in an integrated manner. The third gear planet  21  is engaged with the third internal tooth gear  20  so that they can rotate in an integrated manner. The third gear planet  21  is attached so that it rotates in a condition where it is decentered to the third eccentric shaft  22   a.    
         [0036]     The fourth internal tooth gear  23  is connected to the third gear planet  26  so that they can rotate in an integrated manner. The fourth internal tooth gear  23  is engaged with the fourth gear planet  24  so that they can rotate in an integrated manner. The fourth gear planet  24  is attached so that it rotates in a condition where it is decentered to the fourth eccentric shaft  22   b . The third eccentric shaft  22   a  and the fourth eccentric shaft  22   b  are located to be symmetric to the central axis of the support axis  14 .  
         [0037]     Because the hinge damper of the present embodiment is structured as above, when the document pressing plate P is closed as in  FIG. 1  (B) to the arrow direction, the sector gear  12  integrated with the hinge axis  2  is rotated counterclockwise, as indicated by an arrow in  FIG. 2 , and turns the small gear  13  clockwise.  
         [0038]     When the small gear  13  rotates, together with this movement, the first internal tooth gear  15  rotates and the first gear planet  16  that is engaged with the internal tooth gear  15  rotates in the same direction. The number of teeth N of the first internal tooth gear  15  is more than the number of teeth of the first gear planet  16   n  (N&gt;n). Therefore, when the first internal tooth gear  15  is rotated 360°, speed of the first gear planet  16  is increased for the N/n times of rotation.  
         [0039]     The rotation of the first gear planet  16  also increases the speed of the second gear planet  19  via the second internal tooth gear  18 . Thus, the speed of the third gear planet  21  and the fourth gear planer  24  are increased sequentially.  
         [0040]     Due to the engagement friction (resistance) of each internal gear and gear planet, the rotation energy is absorbed.  
         [0041]     Means to transfer the rotation of the opening/closing device H is not limited to the above mentioned sector gear or other kind of gear and a power transmission mechanism such as a belt or a link may be used.  
         [0042]     The opening/closing device of the hinge damper of the present invention is not limited to the above mentioned document pressing plate of a copier, but is applicable to hinge that opens/closes an open/close member of a scanner, a fax, or a lid of a toilet seat.