Patent Publication Number: US-2009230229-A1

Title: Winding device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a winding device for winding a flexible member. 
     2. Description of the Related Art 
     A head-mounted display (HMD) is well known as a display apparatus of head-mounted type. The HMD is widely used because it allows easy viewing of images on a large screen, facilitates viewing of stereoscopic images, and is movable with the user. Well known examples of a mounting mechanism for mounting the HMD include one in which a belt-like flexible member is fastened around the head, and another having a front-head pressing member and a back-head pressing member. In the latter example, the HMD is mounted or removed by moving the back-head pressing member back and forth to fasten or loosen the HMD on the head. Japanese Patent Laid-Open No. 7-333547 discloses a mounting mechanism using a wire. The disclosed mounting mechanism allows the operator to easily mount the HMD while holding the HMD with one hand. 
     A winding mechanism disclosed in Japanese Patent Laid-Open No. 7-333547 has a structure in which pulling force of a spring causes a ratchet pawl to detent-engage and lock ratchet teeth of a ratchet wheel, so that a wound linear member is prevented from being unwound. It is thus difficult to control backward movement of the linear member at positions other than locking positions between the ratchet pawl and the ratchet teeth. If the operator is unable to stop winding at desired positions, the HMD may be uncomfortable to wear. To solve this problem, it may be possible to increase the number of ratchet teeth so as to allow finer engagement and locking. However, a larger number of ratchet teeth usually require a ratchet wheel having a larger diameter. This is disadvantageous for the HMD which is desired to be compact and lightweight. Alternatively, a one-way mechanism, such as a one-way clutch, may be used as a winding mechanism. The one-way mechanism has a plurality of built-in rollers and allows rotation in only one direction. The one-way mechanism allows the operator to stop winding by stopping rotation at a desired position. However, this makes it complicated to release locking of backward rotation. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in consideration of the above situation. The present invention provides improved operational feeling of a wiring device with a simple configuration. 
     According to an aspect of the present invention, a winding device includes a winding member configured to rotate to wind a flexible member therearound; a first rotating member configured to be rotatable; a second rotating member configured to be rotatable coaxially with the winding member, and having a smaller resistance to rotation in a predetermined direction than that to rotation in a direction opposite the predetermined direction; and an engaging member. When the first rotating member is subjected to a first torque, the engaging member brings the winding member, the first rotating member, and the second rotating member into engagement with one another, so that the winding member becomes rotatable together with the first rotating member in the predetermined direction. When the first rotating member is subjected to a second torque in a direction opposite that of the first torque, the engaging member releases the engagement, so that the winding member becomes rotatable in the direction opposite the predetermined direction. 
     Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is an external view of an HMD according to an embodiment of the present invention. 
         FIG. 2  illustrates the HMD of  FIG. 1  as viewed from the top of the wearer&#39;s head. 
         FIG. 3  illustrates the HMD of  FIG. 1  as viewed from a side of the wearer&#39;s head. 
         FIG. 4  is a cross-sectional view taken along line IV-IV of  FIG. 3  to illustrate a structure of an adjusting unit. 
         FIG. 5  is a cross-sectional view taken along line V-V of  FIG. 2  to illustrate a structure of the adjusting unit. 
         FIG. 6  illustrates an operation of the adjusting unit during a winding operation. 
         FIG. 7  illustrates a state in which wedge members are in contact with a pulley. 
         FIG. 8  is a cross-sectional view taken along line V-V of  FIG. 2  to illustrate a structure of the adjusting unit having alternative components. 
         FIG. 9  is a perspective view of a ski boot provided with the adjusting unit. 
         FIG. 10  is a side view of the ski boot provided with the adjusting unit. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Exemplary embodiments of the present invention will be described in detail in accordance with the accompanying drawings. 
       FIG. 1  is an external view of an HMD according to a first embodiment of the present invention. When wearing the HMD on the head, the wearer can observe images displayed by the HMD. 
     A display unit  101  receives an image signal from a personal computer (PC) or the like, and displays an image to the wearer wearing the HMD. The display unit  101  includes a display device, such as a charge-coupled device (CCD) sensor, for displaying an image, and an optical system. The optical system enlarges an image on the display device, and guides the enlarged image to the eyes of the wearer wearing the HMD. 
     A frame  102  covers the top and sides of the wearer&#39;s head. The frame  102  hangs across the top of the wearer&#39;s head to cover both sides of the head. The frame  102  is connected to the display unit  101 . 
     A tube  103  extends around the back of the wearer&#39;s head. The tube  103  is an elastic accordion tube connected and secured to the frame  102 . 
     A back head pad  104  comes into contact with the back of the wearer&#39;s head. The back head pad  104  is connected and secured to the tube  103 . 
     A front head pad  105  comes into contact with the front of the wearer&#39;s head. The front head pad  105  is connected and secured to the display unit  101 . 
     A top head pad  106  comes into contact with the top of the wearer&#39;s head. As described above, the back head pad  104 , the front head pad  105 , and the top head pad  106  serve as mounting members which allow the wearer to wear the HMD on his/her head. 
     A wire  107  is placed such that it passes internally through the tube  103 , the frame  102 , and the top head pad  106 . The wire  107  extends through a hole  108  in the frame  102  to the outside of the frame  102 , and passes internally through the top head pad  106 . As described above, the wire  107  serves as a wire member. 
     An adjusting unit  109  is used to adjust the tension of the wire  107 . Rotating the adjusting unit  109  allows adjustment of the tension of the wire  107 . A configuration of the adjusting unit  109  will be described in detail below. An end of the wire  107  is connected to point A of the adjusting unit  109  such that the wire  107  is movable about the adjusting unit  109 , while the other end of the wire  107  is connected to point B inside the frame  102 . 
     A guiding member  110  is connected to the frame  102  and guides movement of the top head pad  106 . The top head pad  106  is moved by the tension of the wire  107 . The top head pad  106  is guided by the guiding member  110  to move in a direction perpendicular to the wearer&#39;s head. 
     A leaf spring  111  is fastened to the top of the frame  102  with screws or the like at one end, and fastened to the back head pad  104  with screws or the like at the other end. The leaf spring  111  biases the back head pad  104  in the direction of arrow P. 
       FIG. 2  illustrates the HMD of  FIG. 1  as viewed from the top of the wearer&#39;s head. The configuration of each component is the same as that illustrated in  FIG. 1 . A cross-sectional view taken along line V-V of  FIG. 2  is given in  FIG. 5  to describe an internal structure of the adjusting unit  109 . 
       FIG. 3  illustrates the HMD of  FIG. 1  as viewed from a side of the wearer&#39;s head. The configuration of each component is the same as that illustrated in  FIG. 1 . A cross-sectional view taken along line IV-IV of  FIG. 3  is given in  FIG. 4  to describe an internal structure of the adjusting unit  109 . 
     The HMD according to the first embodiment is configured as described above. The wearer rotates the adjusting unit  109  to wind the wire  107 . When the wire  107  is wound, the back head pad  104  and top head pad  106  connected to the wire  107  are moved in a direction to fasten the HMD to the wearer&#39;s head. That is, by rotating the adjusting unit  109 , the HMD is secured to the wearer&#39;s head. The back head pad  104  and top head pad  106  fastened to the wearer&#39;s head can be loosened by rotating the adjusting unit  109  backward. Next, a structure of the adjusting unit  109  according to the first embodiment will be described in detail. 
       FIG. 4  is a cross-sectional view taken along line IV-IV of  FIG. 3  to illustrate a structure of the adjusting unit  109 . 
       FIG. 5  is a cross-sectional view taken along line V-V of  FIG. 2  to illustrate a structure of the adjusting unit  109 . Hereinafter, a structure of the adjusting unit  109  will be described with reference to  FIG. 4  and  FIG. 5 . 
     An adjusting dial  401  is rotated manually by the wearer. The adjusting dial  401  serves as a first rotating member that is rotatable. It is desirable that the adjusting dial  401  be cylindrical in shape. 
     A support shaft  402  is disposed on the axis of rotation of the adjusting dial  401 . The support shaft  402  has a screw  403  at one end, and is fastened to the frame  102  with a nut  404 . 
     A one-way clutch  405  is on the support shaft  402 . The one-way clutch  405  is rotatable only in a predetermined direction about the support shaft  402 . In the first embodiment, the one-way clutch  405  is rotatable only in a clockwise direction in  FIG. 5 . The one-way clutch  405  has a structure based on publicly known technology, and thus will not be described here. 
     A polygonal piece  406  is press-fitted to the outer periphery of the one-way clutch  405 . The polygonal piece  406  is thus rotatable only in the clockwise direction in  FIG. 5 , and is not rotatable in a counterclockwise direction opposite the clockwise direction. As illustrated in  FIG. 5 , the polygonal piece  406  has a polygonal contour. Each side of the polygon has a groove  407 . The polygonal piece  406  press-fitted to the outer periphery of the one-way clutch  405  serves as a second rotating member having a greater resistance to rotation in directions other than a predetermined direction. 
     A pulley  408  winds the wire  107  therearound to adjust tension applied to the wire  107 . An end of the wire  107  is connected to the pulley  408 . The pulley  408  rotates about the support shaft  402  to wind the wire  107  therearound. The pulley  408  rotates coaxially with the polygonal piece  406 . In the first embodiment, the pulley  408  rotates clockwise in  FIG. 5  to wind the wire  107  therearound, and rotates counterclockwise to loosen the wire  107 . As described above, the pulley  408  serves as a winding member capable of winding the wire  107  therearound. 
     A plurality of wedge members  409  is disposed between the polygonal piece  406  and the pulley  408 . Each of the wedge members  409  has a protrusion  410 , which is fitted in the corresponding groove  407 . Each wedge member  409  serves as an engaging member having a wedge shape. 
     A plurality of boss members  411  is connected to the adjusting dial  401 . As illustrated in  FIG. 5 , more than one of the plurality of boss members  411  are arranged to come into contact with the corresponding wedge member  409 . 
     As described above, the boss members  411  are connected to the adjusting dial  401 . Therefore, when the wearer rotates the adjusting dial  401 , the torque is transmitted through the boss members  411  to the wedge members  409 . 
     A biasing member  412  is provided for each groove  407 . The biasing member  412 , such as a spring, is in contact with the corresponding protrusion  410 , and thus biases the corresponding wedge member  409  clockwise. Next, an operation for mounting the HMD using the adjusting unit  109  will be described in detail. 
     First, the wearer places the HMD on the head, holds the frame  102  with the left hand, and holds the adjusting unit  109  with the right hand. Next, the front of the wearer&#39;s head is fitted to the front head pad  105 . Then, by rotating the adjusting unit  109  clockwise, the back head pad  104  and the top head pad  106  are fastened to the wearer&#39;s head. 
       FIG. 6  illustrates an operation of the adjusting unit  109  during a winding operation. First, when the wearer rotates the adjusting dial  401  of the adjusting unit  109  clockwise, the boss members  411  connected to the adjusting dial  401  are moved clockwise. The boss members  411  come into contact with the corresponding wedge members  409  to move the wedge members  409  clockwise about the support shaft  402 . Since the polygonal piece  406  has a polygonal shape, a gap between the polygonal piece  406  and the pulley  408  is reduced at a position near each vertex of the polygon. Therefore, when the wedge members  409  continue moving, each of the wedge members  409  is inserted into the gap between the polygonal piece  406  and the pulley  408  at a position where the gap is reduced. When the wedge members  409  are inserted into the gap, the adjusting dial  401 , the polygonal piece  406 , and the pulley  408  are brought into engagement with one another through the wedge members  409 . The engagement allows the rotation of the adjusting dial  401  to be transmitted to the polygonal piece  406  and the pulley  408 . This means that if the adjusting dial  401  is rotated clockwise, the polygonal piece  406  and the pulley  408  are also rotated clockwise. Therefore, if the wearer rotates the adjusting dial  401  clockwise after the engagement, the pulley  408  winds the wire  107  therearound, and thus the back head pad  104  and the top head pad  106  can be fastened to the wearer&#39;s head. 
     After completion of the fastening operation, the wound wire  107  is under tension caused by a load applied thereto by the leaf spring  111 . At the same time, the pulley  408  is subjected to a load in the counterclockwise direction. Since the pulley  408  engages with the adjusting dial  401  and the polygonal piece  406 , the adjusting dial  401  and the polygonal piece  406  are also subjected to a load in the counterclockwise direction. However, since the polygonal piece  406  is press-fitted to the outer periphery of the one-way clutch  405  that rotates only clockwise, the polygonal piece  406  does not rotate counterclockwise. This means that the adjusting dial  401  and the pulley  408  that engage with the polygonal piece  406  do not rotate counterclockwise. Therefore, even when the wearer moves his/her hand off the adjusting dial  401  after completion of the fastening, it is possible to keep the back head pad  104  and the top head pad  106  fastened. Thus, as described above, the wearer can fasten the HMD to his/her head and keep the HMD fastened as desired. 
     Next, an operation performed to release fastening will be described. To release fastening, the wearer rotates the adjusting dial  401  counterclockwise. This causes the boss members  411  connected to the adjusting dial  401  to move counterclockwise. When the boss members  411  come into contact with the corresponding wedge members  409 , a load is applied to the wedge members  409  in the counterclockwise direction. When the load applied to the wedge members  409  by the boss members  411  exceeds friction of the wedge members  409  with the polygonal piece  406  and the pulley  408 , the wedge members  409  are moved out of the gap between the polygonal piece  406  and the pulley  408 . This releases the engagement between the polygonal piece  406  and the pulley  408 . Then, the pulley  408  becomes rotatable counterclockwise. As described above, the wound wire  107  is under tension caused by a load applied thereto by the leaf spring  111 . After the engagement is released, however, the pulley  408  rotates counterclockwise to loosen the wound wire  107 . After the engagement is released, if the wearer further rotates the adjusting dial  401  counterclockwise by an amount greater than a predetermined amount, the wedge members  409  are inserted into narrow portions of the gap between the polygonal piece  406  and the pulley  408 , and brought into contact with the pulley  408 . 
       FIG. 7  illustrates a state in which the wedge members  409  are in contact with the pulley  408 . When the wedge members  409  are brought into contact with the pulley  408 , the resulting friction can prevent sudden counterclockwise rotation of the pulley  408  caused by a load from the leaf spring  111 , and thus can safely release the fastening of the wire  107 . That is, it is possible to prevent the wire  107  from suddenly being loosened, and thus to allow fine adjustment. However, if the wedge members  409  are brought into contact with the pulley  408  during counterclockwise rotation of the pulley  408 , the wedge members  409  are inserted deep into the gap between the pulley  408  and the polygonal piece  406 , and so-called jamming may occur. If jamming occurs, it becomes difficult to move the wedge members  409  out of the gap between the pulley  408  and the polygonal piece  406 . To prevent jamming, it is desirable that each groove  407  be provided with a rib or the like. 
     Thus, with a simple configuration, the adjusting unit  109  of the first embodiment is capable of winding the wire  107 , maintaining a wound state of the wire  107  at desired positions, unwinding the wire  107 , and controlling the rotation of the pulley  408  during unwinding of the wire  107 . 
     Rotating the adjusting unit  109  clockwise allows the wearer to wind the wire  107 . After winding the wire  107 , when the wearer moves his/her hand off the adjusting unit  109  at a desired position, the wound state of the wire  107  can be maintained. Rotating the adjusting unit  109  counterclockwise allows the wearer to unwind the wire  107 . Thus, the wearer can intuitively control the winding and unwinding of the wire  107 . 
     In the first embodiment described above, the wire  107  is used to fasten the back head pad  104  and the top head pad  106  to the wearer&#39;s head. However, a strip-shaped member, such as a flat spiral spring, may be used as an alternative to the wire  107 . In other words, the wire  107  may be replaced with any flexible member. 
     The polygonal piece  406  and the wedge members  409  are used in the adjusting unit  109  of the first embodiment. However, components having other shapes may be used to realize the present embodiment. 
       FIG. 8  is a cross-sectional view taken along line V-V of  FIG. 2  to illustrate a structure of the adjusting unit  109  having alternative components. Referring to  FIG. 8 , a star-shaped member  801  is used as an alternative to the polygonal piece  406 . At the same time, ball members  802  are used as alternatives to the wedge members  409 . The biasing members  412 , such as leaf springs, bias the corresponding ball members  802  clockwise. As in the case of  FIG. 7 , the ball members  802  are moved and inserted into narrow portions of a gap between the star-shaped member  801  and the pulley  408 . Therefore, an operation similar to that in the case of  FIG. 7  can be preformed. 
     In the first embodiment described above, the adjusting unit  109  is used to fasten the back head pad  104  and top head pad  106  of the HMD. The adjusting unit  109  may be used for applications other than the HMD. 
     In a second embodiment described below, the adjusting unit  109  is used as a fastening mechanism for ski boots. 
       FIG. 9  is a perspective view of a ski boot provided with the adjusting unit  109 . 
       FIG. 10  is a side view of the ski boot provided with the adjusting unit  109 . 
     Hereinafter, a ski boot provided with the adjusting unit  109  will be described with reference to  FIG. 9  and  FIG. 10 . 
     A shell  901  covers a foot of a wearer of the ski boots. The shell  901  includes a toe portion  902 , a heel portion  903 , an ankle portion  904 , an upper portion  905 , and a foot insertion opening  906 . It is desirable that the shell  901  be made of hard and elastic material. 
     A flapper  907  covers the ankle portion  904  and the upper portion  905 . The flapper  907  surrounds the upper portion  905  and opens toward the front of the wearer&#39;s foot. The flapper  907  is fastened to the shell  901  by bonding, welding, or the like in an area near the Achilles&#39; tendon. 
     The flapper  907  has a plurality of hooks  908  on both sides of an area open toward the front of the wearer&#39;s foot. 
     A wire  909  is provided for fastening the flapper  907 . The wire  909  is threaded through the hooks  908  alternately from side to side. Each of the hooks  908  has a hole to allow the wire  909  to pass through. This can prevent the wire  909  from slipping off the hooks  908 . 
     A tongue-shaped portion  910  is provided for adjusting the width of the foot insertion opening  906 . The tongue-shaped portion  910  extends backward from the toe portion  902  to the ankle portion  904 . The tongue-shaped portion  910  is disposed inside the flapper  907 . The tongue-shaped portion  910  is fastened to the shell  901  at one end by bonding, welding, or the like in an area near the toe portion  902 , but is free at the other end. Therefore, the area of the foot insertion opening  906  can be changed to fit the size of the wearer&#39;s foot. Since the inside of the tongue-shaped portion  910  is to be in direct contact with the wearer&#39;s foot, it is desirable that the tongue-shaped portion  910  be made of flexible material. 
     An adjusting unit  911  controls winding of the wire  909 . The structure of the adjusting unit  911  is the same as that of the adjusting unit  109 . The wearer rotates the adjusting unit  911  to control winding of the wire  909 . The internal structure of the adjusting unit  911  is the same as that of the adjusting unit  109  illustrated in  FIG. 4  and  FIG. 5 . 
     An operation of putting on the ski boot having the above-described configuration, and effects of the operation will now be described. First, when the wire  909  is loose, the tongue-shaped portion  910  is pulled forward. This increases the area of the foot insertion opening  906  of the shell  901  and allows insertion of the wearer&#39;s foot. Then, the wearer&#39;s foot is inserted into the shell  901 . After the insertion, the tongue-shaped portion  910  is pulled to the inside of the flapper  907 . Then, the wire  909  is wound by rotating the adjusting dial  401  of the adjusting unit  911  in CW direction shown in  FIG. 9 . By winding the wire  909 , the flapper  907  is fastened and deformed to fit the shape of the wearer&#39;s foot. Thus, the wearer&#39;s ankle is secured. 
     Next, an operation performed to remove the ski boot from the wearer&#39;s foot will be described. First, the wearer rotates the adjusting dial  401  in CCW direction shown in  FIG. 9 . Thus, since the wedge members  409 , the pulley  408 , and the polygonal piece  406  inside the adjusting unit  911  are brought out of engagement, the pulley  408  having the wire  909  wound therearound becomes freely rotatable. At the same time, the flapper  907  and the tongue-shaped portion  910  around which the wire  909  is wound are released from the deformed state and restored to their initial shapes. The pulley  408  rotates until the line tension of the wire  909  becomes substantially zero. Then, by pulling the tongue-shaped portion  910  to the outside of the shell  901 , the ski boot can be removed from the wearer&#39;s foot. 
     Thus, with a simple configuration, the second embodiment allows winding of the wire  909 , locking of the wire  909  at desired positions, unlocking, and rotation control during the unlocking. Thus, it is possible to realize ski boots that are lightweight, inexpensive, and capable of providing reliable operation. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2008-064250 filed Mar. 13, 2008, which hereby incorporated by reference herein in its entirety.