Patent Grant
9416578
The present invention relates to a door closer.
As a type of door closer, a floor hinge embedded in a floor is disclosed in Patent Literature 1. The floor hinge proposed by the present applicant in Patent Literature 1 is configured to include a spring retaining seat on a fixed side, a return spring, and a piston in this order from the side closest to a main shaft. In other words, the floor hinge is configured such that the return spring is interposed between the piston and the spring retaining seat on the fixed side and an end surface of the piston on the main shaft side serves as a spring retaining seat on a moving side. The piston moves toward the spring retaining seat on the fixed side when a door is opened, and accordingly, the return spring is compressed to store the closing force. The floor hinge is configured to use the closing force (spring force) of the return spring to rotate the main shaft and automatically close the door.
However, in the floor hinge configured in this manner, the spring force of the return spring cannot be adjusted from the outside of a main body housing without disassembly. Accordingly, depending on the relationship with the size or weight of the door, an excessively large force may be required to open the door, or the door may not be fully dosed.
The present invention has been made to solve the above problems. A door closer according to the present invention includes: a main shaft that rotates upon a door opening/closing operation; a main body housing that pivotally supports the main shaft and includes an oil chamber filled with hydraulic oil; a piston that partitions the oil chamber into a first oil chamber on a side close to the main shaft and a second oil chamber on a side opposite to the main shaft, and moves toward the first oil chamber upon the door opening operation and moves toward the second oil chamber upon the door closing operation; a piston drive section that converts a rotation movement of the main shaft into a linear movement to drive the piston; and a return spring located on an identical line to the piston and interposed between a spring retaining seat on a fixed side close to the main shaft and a spring retaining seat on a moving side distant from the main shaft, the return spring storing a closing force upon being compressed by the spring retaining seat on the moving side moving closer to the spring retaining seat on the fixed side upon the door opening operation, and the door closer further includes a spring force adjustment mechanism configured to change a position of a spring retaining member having the spring retaining seat on the fixed side in an axial direction of the piston with respect to the main body housing, and configured to adjust a spring force of the return spring by a change of the position of the spring retaining member through an operation from an outside of the main body housing.
In the door closer with such configuration, the piston moves toward the second oil chamber upon the door closing operation. Accordingly, the pressure in the first oil chamber is not increased upon the door closing operation. Therefore, there is no concern that hydraulic oil is leaked from a bearing portion of the main shaft due to an increase in pressure of the first oil chamber. The door closer includes the spring force adjustment mechanism configured to change the position of the spring retaining member with respect to the main body housing. Thus, by operating the spring force adjustment mechanism from the outside of the main body housing, the position of the spring retaining member can be changed and the spring force of the return spring can be easily adjusted.
Specifically, it is preferable that the piston is located between the spring retaining member and the main shaft, the piston and the spring retaining seat on the moving side are connected by a connecting rod penetrating the spring retaining member, the connecting rod has a tubular portion opening at an end on the opposite side to the piston, and the spring force adjustment mechanism includes: an operation section provided to an end of the main body housing on a side close to the second oil chamber; and a transmission section that transmits a movement of the operation section to the spring retaining member through an inside of the tubular portion of the connecting rod to move the spring retaining member in the axial direction of the piston.
In the configuration where the piston is located between the spring retaining member and the main shaft, i.e., in the configuration where the piston is located on the side close to the main shaft with respect to the spring retaining member, the spring force adjustment mechanism can be configured easily, as compared to the configuration where the piston is located on the side opposite to the main shaft with respect to the spring retaining member. The operation section is provided to the end of the main body housing on the side close to the second oil chamber. Thus, the operation section can be easily operated. Moreover, the spring retaining member is located away from the end of the main body housing on the side close to the second oil chamber. In addition, even if the connecting rod or return spring exists in between, the transmission section uses the internal space of the tubular portion of the connecting rod to transmit the movement of the operation section. Thus, the movement of the operation section can be securely transmitted, and the increase in size of the main body housing can be prevented.
Moreover, it is preferable that a horizontal hole is formed in a peripheral wall of the tubular portion of the connecting rod, and the spring force adjustment mechanism includes: an adjustment shaft that penetrates the end of the main body housing on the side close to the second oil chamber and is inserted through the tubular portion of the connecting rod; and a coordinating member that coordinates the adjustment shaft with the spring retaining member via the horizontal hole of the connecting rod.
The adjustment shaft is inserted into the connecting rod. The coordinating member coordinates the adjustment shaft with the spring retaining member via the horizontal hole of the connecting rod. Consequently, by operating the protruding portion of the adjustment shaft, which protrudes from the end of the main body housing on the side close to the second oil chamber side, the position of the spring retaining member can be easily changed.
Furthermore, it is preferable that the connecting rod has a tubular shape over a total length, a communicating hole with a check valve communicating between the first oil chamber and the second oil chamber is formed at a center of the piston, and the communicating hole is located inside an end of the connecting rod on a side close to the piston.
The communicating hole with the check valve is formed in the piston. Accordingly, the hydraulic oil can pass from the communicating hole of the piston upon the door opening operation. Furthermore, the communicating hole can be closed by the check valve upon the door closing operation. Moreover, the connecting rod is formed into a tube shape over its total length. Accordingly, the communicating hole can be located inside the end on the piston side of the connecting rod. Therefore, the size increase of the piston and the main body housing can be prevented as compared to the configuration where the communicating hole is located outside the connecting rod. In addition, the connecting rod is formed into a tube shape up to the end on the side close to the piston. Thus, the hydraulic oil can pass from the communicating hole of the piston through the inside of the connecting rod. If the horizontal hole is formed in the connecting rod, the hydraulic oil can move easily from the inside to the outside of the connecting rod through the horizontal hole.
Furthermore, it is preferable that the spring force adjustment mechanism includes: an operation section provided to an end of the main body housing on a side close to the second oil chamber; and a transmission section that transmits a movement of the operation section to the spring retaining member to move the spring retaining member in the axial direction of the piston, the transmission section is provided with a flange portion that is rotated by an operation of the operation section, and a rolling element holding plate that holds a plurality of rolling elements rolling by rotation of the flange portion is arranged in the main body housing.
The flange portion provided to the transmission section rotates while rolling the plurality of rolling elements held by the rolling element holding plate. Thus, operability upon adjustment of the spring force can be improved.
Furthermore, it is preferable that a recess is formed in the main body housing, and an expansion absorption member is accommodated in the recess to come into contact with hydraulic oil in the first oil chamber.
The expansion absorption member accommodated in the recess is in contact with the hydraulic oil in the first oil chamber. Thus, the hydraulic oil, which has expanded due to an increase in temperature, can be prevented from leaking from the main body housing.
Furthermore, it is preferable that the door closer includes pullout prevention means that prevents the expansion absorption member from coming out of the recess.
By virtue of the pullout prevention means, the expansion absorption member can be prevented from coming out of the recess.
As described above, in the door closer according to the present invention, the position of the spring retaining member having the spring retaining seat on the fixed side can be changed by the spring force adjustment mechanism from the outside of the main body housing. Thus, the spring force of the return spring can be easily adjusted in accordance with the size and weight of a door.
Hereinafter, a floor hinge as a door closer according to one embodiment of the present invention will be described with reference to
The main body housing 1 includes a main section 10 constituting its main part, an upper cap 11 mounted at the top on the rear side, and a horizontal cap 12 mounted at the end on the front side. The oil chamber filled with hydraulic oil is formed in the main body housing 1.
A main shaft 3 is pivotally supported in the rear of the main body housing 1. The main shaft 3 serves as the axis of rotation of a door. The main shaft 3 rotates in response to the door opening/closing operation. The center of the main shaft 3 is located on the center line (axis) of the piston 2 in planar view. The main shaft 3 is rotatably supported by the upper cap 11 and a bottom portion of the main section 10 via bearings 13 and 14. An upper portion of the main shaft 3 protrudes upwardly by a predetermined length from the upper cap 11. A heart-shaped cam 4 is provided to the main shaft 3. The cam 4 and the main shaft 3 rotate integrally. The cam 4 and the main shaft 3 may be integrally processed and formed to constitute a single member. Alternatively, the cam 4 may form a floor hinge as a separate member from the main shaft 3. In any case, the cam 4 rotates integrally with the main shaft 3 upon the door opening/closing operation, and converts the rotation operation of the main shaft 3 into linear motion in the axial direction. Accordingly, the cam 4 functions as a piston drive section that drives the piston 2. The cam 4 is a plate cam whose peripheral surface is a cam surface. Only an area within a predetermined angle of the entire periphery is a section to be used in the door opening/closing operation. In the embodiment, the peripheral surface of the cam 4 has a symmetrical shape. One area of the two 180-degree areas is the section to be used. However, the peripheral surface of the cam 4 may have an asymmetrical shape. A recess 4ais formed at one point in the cam surface. The recess 4a is formed at a position corresponding to a door closed state, i.e., when the opening degree of the door is zero degrees.
Sliding plates 5 are respectively placed above and below the cam 4. A roller 6 as a cam follower that rotates in contact with the cam 4 is provided between the sliding plates 5. A support shaft of the roller 6 is mounted to the sliding plates 5. Therefore, when the cam 4 rotates together with the main shaft 3, the sliding plates 5 move in the axial direction via the roller 6. When the cam 4 rotates 180 degrees, the states illustrated in
The piston 2 partitions the oil chamber into a first oil chamber 15 on the main shaft 3 side, i.e., on the rear side, and a second oil chamber 16 on the opposite side to the main shaft 3, i.e., on the front side. The piston 2 moves toward the first oil chamber 15 side, i.e., the rear side, upon the door opening operation, and moves toward the second oil chamber 16 side, i.e., the front side, upon the door closing operation. The piston 2 includes a tubular outer cylinder 20 and a tubular inner cylinder 21 press-fitted and integrated into the outer cylinder 20. The inner cylinder 21 is formed to have a small diameter portion on the front side and a large diameter portion on the rear side. The inside of the large diameter portion serves as the recess. The sliding plates 5 are inserted therein.
Moreover, a check valve 22 is provided inside the small diameter portion of the inner cylinder 21. Specifically, as illustrated in cross section of
As illustrated in
A tubular main connecting rod 30 is connected to the piston 2. The main connecting rod 30 is connected to the front side of the piston 2 such that its axis coincides with the axis of the piston 2. The main connecting rod 30 extends from the piston 2 toward the front side. An external thread portion is formed on the small diameter portion of the inner cylinder 21 of the piston 2. A ring-shaped space is provided between the small diameter portion and the outer cylinder 20. A rear end of the main connecting rod 30 enters the space to be screwed onto the small diameter portion of the inner cylinder 21 of the piston. Therefore, the check valve 22 of the piston 2 is located inside the rear end of the main connecting rod 30.
A tubular auxiliary connecting rod 31 is connected to the front side of the main connecting rod 30. The auxiliary connecting rod 31 is screwed in an internal thread portion on an inner peripheral surface of a front end of the main connecting rod 30. Moreover, a ring-shaped flange portion 32 is formed at a front end of the auxiliary connecting rod 31. A rear end surface of the flange portion 32 forms a spring retaining seat on the moving side. Moreover, the main connecting rod 30 and the auxiliary connecting rod 31 constitute a connecting rod that connects the piston 2 and the spring retaining seat on the moving side.
The spring retaining member 40 is located on the front side of the piston 2 at a position a predetermined distance away from the piston 2 in the door closed state. A return spring 50 made of a coil spring is located on the front side of the spring retaining member 40. The spring retaining member 40 has a disc shape with a through hole in the center. The main connecting rod 30 penetrates through the spring retaining member 40. A front end surface of the spring retaining member 40 forms a spring retaining seat on the fixed side. In other words, the return spring 50 is interposed between the spring retaining member 40 and the flange portion 32 of the auxiliary connecting rod 31. The connecting rod is inserted in the return spring 50. Accordingly, the spring retaining member 40 is always pressed and biased toward the rear by the return spring 50, and the auxiliary connecting rod 31 is always pressed and biased toward the front by the return spring 50. The biasing force acting on the auxiliary connecting rod 31 is transmitted from the main connecting rod 30 to the piston 2, the sliding plates 5, and the cam 4. Therefore, upon the door opening operation, the piston 2 and the connecting rod move toward the rear side to compress the return spring 50 as illustrated in
In addition, the floor hinge is formed using the spring retaining member 40 as a separate member from the main body housing 1. The floor hinge is formed such that the spring retaining member 40 is slidable in the axial direction with respect to the main body housing 1. In
Next, a description will be given of a spring force adjustment mechanism that changes the position of the spring retaining member 40 by an operation from the outside of the main body housing 1 to adjust the spring force of the return spring 50. In
The spring force adjustment mechanism includes the adjustment shaft and a coordinating pin 60 as a coordinating member. The adjustment shaft is on the same axis as those of the piston 2, the return spring 50, and the connecting rod. The adjustment shaft includes a first adjustment shaft 61 and a second adjustment shaft 62. The first adjustment shaft 61 penetrates the center of the horizontal cap 12 in the axial direction. A front end portion 61a of the first adjustment shaft 61 protrudes from the horizontal cap 12 toward the front side. The front end portion 61a of the first adjustment shaft 61, which protrudes from the horizontal cap 12, serves as an operation section. This portion is rotated to operate the adjustment shaft. Moreover, the first adjustment shaft 61 includes a flange portion 61b, almost all of which is accommodated in a recess 12a formed on the rear end surface side of the horizontal cap 12. The flange portion 61b is accommodated in the recess 12a of the horizontal cap 12 such that its front end surface and side surfaces do not come into contact with the horizontal cap 12.
A disc-shaped rolling element holding plate 70 is placed in the second oil chamber 16 by being fitted into the main body housing 1 through a hole portion for mounting the horizontal cap 12. An outer edge of a rear end surface of the rolling element holding plate 70 is in contact with a stepped portion 71 on the inner wall surface of the main body housing 1. Consequently, the position of the rolling element holding plate 70 is determined in the second oil chamber 16. A hole 70a is formed at the center of the rolling element holding plate 70. The first adjustment shaft 61 penetrates through the hole 70a. Moreover, a groove portion 70b is formed in a front end surface of the rolling element holding plate 70. A cage 72 that rollably holds a plurality of needle rollers 73 is fitted and accommodated in the groove portion 70b. As illustrated in
The first adjustment shaft 61 is inserted in the connecting rod. An external thread portion is formed on an outer peripheral surface of a rear end of the first adjustment shaft 61. The external thread portion is screwed in an internal thread portion formed in an inner peripheral surface of a front end of the second adjustment shaft 62. The entirety of the second adjustment shaft 62 is inserted in the connecting rod, specifically, in the main connecting rod 30. By rotating the first adjustment shaft 61, the second adjustment shaft 62 slides in the axial direction by virtue of the screw feeding mechanism.
The coordinating pin 60 is mounted and fixed to the rear of the second adjustment shaft 62. The coordinating pin 60 has a vertical axis and penetrates the second adjustment shaft 62 vertically. A horizontal hole 63 having a long hole shape that is long in the axial direction is formed in each of the upper and lower parts of a peripheral wall of the main connecting rod 30. Upper and lower ends of the coordinating pin 60 are inserted through the horizontal holes 63, and extend upwardly and downwardly. A pair of upper and lower engagement recesses 42 is formed in an inner peripheral surface of the spring retaining member 40. The upper and lower ends of the coordinating pin 60 are respectively engaged in the engagement recesses 42. A flat surface 60a is formed on each of front portions of the upper and lower ends of the coordinating pin 60. A flat surface is formed, corresponding to the flat surface 60a, also on a front portion of a wall surface of the engagement recess 42 of the spring retaining member 40. Therefore, the coordinating pin 60 and the spring retaining member 40 are in a relationship where their flat surfaces are in contact with each other. The flat surface 60a of the coordinating pin 60 moves the spring retaining member 40 in the axial direction while pressing the flat surface of the spring retaining member 40 toward the front side. In this manner, in the embodiment, the front end portion 61a of the first adjustment shaft 61, which protrudes from the horizontal cap 12, serves as the operation section that is rotated and operated. The rotation of the first adjustment shaft 61 is converted into the movement of the second adjustment shaft 62 in the axial direction by virtue of the screw feeding mechanism. In this manner, the rotation of the first adjustment shaft 61 is transmitted by the coordinating pin 60 to spring retaining member 40 through the horizontal holes 63 of the main connecting rod 30. In the embodiment, the first adjustment shaft 61, the second adjustment shaft 62, and the coordinating pin 60 constitute a transmission section that transmits the movement of the operation section to the spring retaining member 40.
A recess 62a is formed in a rear end surface of the second adjustment shaft 62. As illustrated in
A recess 10A for accommodating a sponge rubber 80 as an expansion absorption member is formed in a portion that defines the first oil chamber 15 at the bottom of the main section 10 of the main body housing 1. As illustrated in
In the floor hinge configured as described above, the piston 2 moves toward the first oil chamber 15 side upon the door opening operation and moves toward the second oil chamber 16 side upon the door closing operation. Accordingly, the hydraulic pressure on the first oil chamber 15 side is not increased upon the door closing operation. Thus, oil leakage from an area of the bearing 13 of the main shaft 3, which is caused by an increase in pressure of the first oil chamber 15, can be suppressed. Moreover, the recess 10A is formed in the main section 10 of the main body housing 1. The sponge rubber 80 is accommodated in the recess 10A. Thus, oil is prevented from leaking from the main body housing 1 (for example, between the upper cap 11 and the main section 10) due to the expansion of the hydraulic oil caused by temperature increase. The sponge rubber 80 accommodated in the recess 10A comes into contact with hydraulic oil in the first oil chamber 15. Thus, the sponge rubber 80 does not inhibit the movement of the cam 4 and the sliding plates 5 in the first oil chamber 15. Moreover, the pin 82 securely prevents the sponge rubber 80 accommodated in an unmovable manner in the recess 10A from coming out of the recess 10A. Furthermore, the recess 10A is formed to surround the bearing mounting portion 10C of the main section 10. Thus, a sufficient space to accommodate the sponge rubber 80 can be secured.
The front end portion 61a of the first adjustment shaft 61 protrudes from the horizontal cap 12. Accordingly, by rotating the front end portion 61a of the first adjustment shaft 61, it is possible to easily change the position of the spring retaining member 40 in the axial direction and easily adjust the spring force of the return spring 50 from the outside of the main body housing 1. Especially, the front end portion 61a of the first adjustment shaft 61, which protrudes from the horizontal cap 12, can be operated as the operation section. Hence, an increase in size of the main body housing 1 can be prevented, and additionally, the operation of adjusting the spring force is easy.
The rolling element holding plate 70 is placed in the main body housing 1. When the front end portion 61a of the first adjustment shaft 61 is rotated, the flange portion 61b of the first adjustment shaft 61 rotates while rolling the plurality of needle rollers 73 held by the rolling element holding plate 70. The rolling element holding plate 70 can receive a load in the axial direction when the first adjustment shaft 61 is rotated. Thus, the rotation operation of the first adjustment shaft 61 does not require a large force. In addition, operability upon adjustment of the spring force is improved.
Moreover, the connecting rod is formed into a tube shape and the first adjustment shaft 61 and the second adjustment shaft 62 are inserted into the connecting rod. Accordingly, the movement of the operation section can be transmitted using an internal space of the connecting rod. Thus, the transmission section is formed without making the main body housing 1 thick in the vertical direction and wide in the horizontal direction. The pair of horizontal holes 63, which faces at 180 degrees, is formed in the connecting rod. The coordinating pin 60 protrudes from the horizontal holes 63 outwardly in the radial direction. Thus, it is possible to move the spring retaining member 40 smoothly and compress the return spring 50. In addition, the spring retaining member 40 moves in the axial direction without rotating. Thus, when the spring force of the return spring 50 is adjusted, rubbing noise does not occur between the return spring 50 and the spring retaining member 40. In the configuration where the spring retaining member 40 rotates together with the adjustment shaft, the spring retaining member 40 slides with respect to the return spring 50 while rotating in the circumferential direction. Accordingly, the rubbing noise occurs. In the configuration where the spring retaining member 40 moves in the axial direction, however, it is possible to prevent the rubbing noise from occurring between the spring retaining member 40 and the return spring 50. In addition, the adjustment can be made smoothly.
On the other hand, the piston 2 is located on the rear side of the spring retaining member 40, i.e., on the main shaft 3 side. In other words, the floor hinge is not configured such that the adjustment shaft penetrates the piston 2. Therefore, the spring force adjustment mechanism can be configured easily. The check valve 22 of the piston 2 can be also arranged easily. The length of the piston 2 in the axial direction can be prevented from becoming excessively long. The flow control channels 17 and 18 can be also arranged easily. Moreover, the floor hinge has an overlapping structure where the sliding plates 5 are inserted in the rear of the piston 2 by a predetermined length. Accordingly also in the configuration where the piston 2 is placed on the rear side of the spring retaining member 40, the total dimension of the main body housing 1 in the axial direction can be reduced.
The connecting rod has a tubular shape up to the rear end, and the check valve 22 is located inside the rear end. Accordingly, upon the door opening operation, the hydraulic oil that has moved from the communicating hole of the piston 2 to the second oil chamber 16 side can pass through the connecting rod. Furthermore, the hydraulic oil can also move easily from the horizontal holes 63 of the connecting rod to the outside of the connecting rod. Moreover, in the configuration where the check valve 22 is located outside the connecting rod, the piston 2 is increased in diameter. However, since the connecting rod is formed into a tube shape and the check valve 22 is placed inside the connecting rod, it is possible to prevent the size increase of the piston 2 and the main body housing 1.
The floor hinge according to the embodiment is configured such that the coordinating pin 60 penetrates the connecting rod vertically. However, the floor hinge may be configured such that the coordinating pin 60 penetrates the connecting rod horizontally. The direction may be any direction. However, in any case, the floor hinge is preferred to be configured such that the coordinating pin 60 penetrates the connecting rod in the radial direction. Moreover, the floor hinge may be configured such that the coordinating pin 60 is located on the rear side of the spring retaining member 40. However, as described above, the configuration where the coordinating pin 60 is inserted into the spring retaining member 40 from the radially inner side can reduce the dimension in the front and back direction, as compared to the configuration where the coordinating pin 60 is arranged on the rear side of the spring retaining member 40.
The heart-shaped cam 4 is used as the piston drive section. However, the floor hinge may be formed from a rack and pinion. However, in the case of the floor hinge, a large driving force is required. Therefore, the use of the cam 4 is preferable.
The check valve 22 is placed at the center of the piston 2. However, it may be placed outside the connecting rod. Moreover, the connecting rod has a tubular shape over its total length. However, the connecting rod may be solid in the rear and tubular only in the front. Moreover, the connecting rod and the piston 2 may be integrated as a single member. The floor hinge may be configured to form the main connecting rod 30 and the piston 2 as a single member and form the auxiliary connecting rod 31 as a separate member.
Furthermore, the floor hinge may be configured to place the piston 2 on the front side of the spring retaining member 40. In other words, the rear end surface of the piston 2 may serve as the spring retaining seat on the moving side, and the return spring 50 may be interposed between the piston 2 and the spring retaining member 40.
Moreover, the protruding portion of the adjustment shaft, which protrudes from the horizontal cap 12, functions as the operation section. However, the floor hinge may be configured such that the operation section is simply exposed without protruding from die horizontal cap 12. Although a rotation operation is preferred as an operation of the operation section, its operation is not limited to the rotation operation. For example, its operation may be an operation for moving the operation section in the axial direction.
Moreover, the recess 10A is formed in the main section 10 of the housing main body 1. However, the recess for accommodating the expansion absorption member may be formed in the upper cap 11.
Moreover, the pullout prevention means is the pin 82. However, a screw or the like may be used as the pullout prevention means.
The case of the floor hinge has been described. However, the door closer according to the embodiment is applicable to various door closers to be mounted on an upper part of or inside a door, or on a door frame.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-041651 | Mar 2013 | JP | national |
| 2013-052802 | Mar 2013 | JP | national |
| 2013-188389 | Sep 2013 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/079869 | 11/5/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2014/136317 | 9/12/2014 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3701180 | Jentsch | Oct 1972 | A |
| 3724023 | Tillmann | Apr 1973 | A |
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| 5243735 | O'Brien, II | Sep 1993 | A |
| 5337448 | Brown | Aug 1994 | A |
| 5417013 | Tillmann | May 1995 | A |
| 5666692 | Toledo | Sep 1997 | A |
| 5802670 | Bienek | Sep 1998 | A |
| 5901412 | Jentsch | May 1999 | A |
| 6260236 | Toledo | Jul 2001 | B1 |
| 20070256275 | Winkler | Nov 2007 | A1 |
| 20080034535 | Chiang | Feb 2008 | A1 |
| Number | Date | Country |
|---|---|---|
| 0407150 | Jan 1991 | EP |
| 4535631 | Nov 1970 | JP |
| 755254 | Dec 1995 | JP |
| 2012241439 | Dec 2012 | JP |
| Entry |
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| International Search Report dated Jan. 21, 2014 filed in PCT/JP2013/079869. |
| Number | Date | Country | |
|---|---|---|---|
| 20150345202 A1 | Dec 2015 | US |
