# Patent

## Title
Drawing device

## Abstract

A drawing device increases durability of dampers. A slider 14 and a damper base 22 are provided slidable on a base 12 of a drawing device. The damper base 22 is provided with a damper lock 28 which engages with the base 12 to prevent the damper base 22 from sliding and also makes the damper base slidable in the longitudinal direction. When the slider 14 moves relative to the base 12 in the longitudinal direction by a biasing force of an elastic member 15, the damper base in engagement with the base 12 by the damper lock 28 first moves relative to the slider 14 and thereby, the first damper 24 generates a damping force. Then, the damper lock 28 and the base 12 are disengaged, the base 12 moves relative to the damper base 22 and the slider, and thereby, the second damper 25 generates a damping force.

## Background
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drawing device that generates a force for assisting manual one-way movement of an opening/closing body such as a sliding door, a folding door or a drawer.
2. Related Art
A sliding door is sometimes provided with a drawing device that generates an assisting force in a closing direction for the sliding door that moves in the closing direction. Atypical drawing device is called a self-closing device, and when the sliding door is moved manually along the guide rail in the closing direction and reaches a certain point, a biasing force in the closing direction by the elastic member is exerted on the sliding door. Then, the sliding door moves automatically in the closing direction and stops at a fully closed position (see, for example, Japanese Patent Application Laid-open No. 2008-285933).
On an upper part of a frame, a guide rail is attached that extends in the moving direction of the sliding door. The drawing device is held in the guide rail and can slide in the longitudinal direction of the guide rail by rollers. The sliding door suspends from the drawing device. When the sliding door is pushed manually and moved in the closing direction, the drawing device also moves in the closing direction. There is a pin fixed to the guide rail. When the drawing device moves in the closing direction and reaches a predetermined position, a slider of the drawing device catches the pin. Then, lock between the slier and a base of the drawing device is released and the base moves in the closing direction toward the slider by the elastic member of the drawing device. As the slider holds the pin, it does not move, and hence, the base moves in the closing direction. As the sliding door suspends from the base of the drawing device, the sliding door moves in the closing direction in accordance with movement of the base in the closing direction.
In order to prevent strong collision of the sliding door against the frame or door stop by the biasing force of the elastic member, the drawing device is provided with a damper. In the Japanese Patent Application Laid-open No. 2006-200300, there are two rotary dampers provided in the drawing device, which generate damping forces in accordance with the strength of the biasing force of the elastic member thereby to smooth movement of the sliding door. That is, at the initial operation time when a large biasing force acts on the drawing device, the two rotary dampers are operated to increase the damping forces, and immediately before the sliding door is closed with a small biasing force that acts on the drawing device, one of the rotary dampers is operated to reduce the damping force.
In the drawing device as disclosed in Japanese Patent Application Laid-open No. 2006-200300, on a drawing frame of the drawing device, the two rotary dampers are mounted with a space created therebetween in the longitudinal direction, and the rotary dampers have pinions. The guide rail mounted on the frame has a rack. When an operating member mounted on the sliding door operates a catch member, a pulling coil spring operates to move the drawing frame in the closing direction relative to the guide rail, and at the same time, the pinions move on the rack. Then, the rotary dampers rotate, and a predetermined damping force can be obtained. When the drawing frame moves further, the first pinion gets out of the rack, the damping force is reduced accordingly and the sliding door closes smoothly.
In the above-mentioned drawing device, the two rotary dampers are aligned in the moving direction of the sliding door in order to obtain predetermined damping performance. As a rotary damper which is positioned to the closing side of the sliding door is operated constantly from the time when the drawing device starts to the time when the sliding door is closed completely, there arises a problem of durability.
Then, the present invention has an object to provide a drawing device that is capable of increasing the durability of the damper.
BRIEF SUMMARY OF THE INVENTION
In order to solve the above-mentioned problems, the first aspect of the present invention is a drawing device for giving a biasing force in one direction to an opening/closing body movable relative to a frame when the opening/closing body moves in the one direction, comprising: a trigger pin which is attached to one of the frame and the opening/closing body; and a drawing device main body which is attached to an other of the frame and the opening/closing body and provided for catching the trigger pin to give the opening/closing body the biasing force in the one direction, the drawing device main body having a base which is attached to the other of the frame and the opening/closing body and elongates in a moving direction of the opening/closing body, a slider which has a trigger catcher capable of catching the trigger pin and is slidable relative to the base in a longitudinal direction while the trigger catcher catches the trigger pin, an elastic member which spans the base to the slider, gives the biasing force so as to move the slider relative to the base in the longitudinal direction and thereby gives the biasing force in the one direction to the opening/closing body, and a damper mechanism which generates a damping force against the slider moving relative to the base in the longitudinal direction by the biasing force of the elastic member, the damper mechanism having a first damper and a second damper as damper sources each for generating a damping force, a damper base which is provided in the base to be slidable in the longitudinal direction and a damper lock which is provided in the damper base, and which engages with the base so as to prevent the damper base from sliding relative to the base in the longitudinal direction and releases engagement with the base so as to make the damper base slidable relative to the base in the longitudinal direction, wherein when the slider moves relative to the base in the longitudinal direction by the biasing force of the elastic member, first the damper base engaging with the base by the damper lock moves relative to the slider thereby the first damper generating the damping force, and then, the damper lock and the base are disengaged and the base moves relative to the damper base and the slider, thereby the second damper generating the damping force.
According to the present invention, the first damper is operated first, then, the first damper is switched to the second damper and the second damper. With this structure, as the first or second damper is prevented from operating from the time when the drawing device starts to operate to the time when the opening/closing body gets closed, it is possible to increase the durability of the dampers.



BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing wherein one example is illustrated by way of example, in which;
FIGS. 1A to 1C are outline views of a drawing device according to an exemplary embodiment of the present invention (FIG. 1A is a plan view, FIG. 1B is a side view and FIG. 1C is a front view);
FIGS. 2A to 2D are detail views of a guide rail (FIG. 2A is a cross sectional view of the guide rail at the position of a trigger pin, FIG. 2B is a cross sectional view of the guide rail at the position of a countersunk screw, FIG. 2C is a cross sectional view of the guide rail taken along the longitudinal direction, and FIG. 2D is a front view thereof);
FIGS. 3A and 3B are plan views of a drawing device main body (FIG. 3A illustrates the drawing device main body assembled and FIG. 3B illustrates main parts of the drawing device main body disassembled);
FIGS. 4A and 4B are cross sectional views of the drawing device main body (FIG. 4A illustrates the drawing device main body assembled and FIG. 4B illustrates main parts of the drawing device main body disassembled);
FIGS. 5A to 5C are views of a base (FIG. 5A is a plan view, FIG. 5B is a side view and FIG. 5C is a cross sectional view) ;
FIGS. 6A to 6F illustrate a slider (FIG. 6A is a plan view, FIG. 6B is a side view, FIG. 6C is a bottom view, FIG. 6D is a cross sectional view, FIG. 6E is a left-side front view, and FIG. 6F is a right-side front view);
FIGS. 7A to 7D illustrate a trigger pusher (FIG. 7A is a plan view, FIG. 7B is a side view, FIG. 7C is a left-side front view, and FIG. 7D is a right-side front view);
FIGS. 8A to 8D illustrate a trigger catcher (FIG. 8A is a plan view, FIG. 8B is a side view, FIG. 8C is a bottom view, and FIG. 8D is a right-side front view);
FIGS. 9A to 9C illustrate a malfunction reset cam (FIG. 9A is a plan view, FIG. 9B is a side view, and FIG. 9C is a right-side front view);
FIGS. 10A to 10D illustrate a damper base (FIG. 10A is a plan view, FIG. 10B is a side view, FIG. 10C is a left-side front view and FIG. 10D is a right-side front view);
FIGS. 11A to 11C illustrate a damper lock (FIG. 11A is a plan view, FIG. 11B is a side view, and FIG. 11C is a left-side front view);
FIG. 12 is a side view of a linear damper;
FIGS. 13A to 13C illustrate a rotary damper (FIG. 13A is a plan view, FIG. 13B is a side view, and FIG. 13C is a left-side front view);
FIGS. 14A to 14C are plan views for explaining the operation of the drawing device when the sliding door gets closed (FIG. 14A illustrates the drawing device when the drawing operation starts, FIG. 14B illustrates the drawing device when the dampers are switched, and FIG. 14C illustrates the drawing device when the sliding door that is fully closed);
FIGS. 15A to 15C are cross sectional views for explaining the operation of the drawing device when the sliding door gets closed (FIG. 15A illustrates the drawing device when the drawing operation starts, FIG. 15B illustrates the drawing device when the dampers are switched, and FIG. 15C illustrates the drawing device when the sliding door is fully closed);
FIGS. 16(1-1) to 16(4-2) are detail views in which the trigger catcher 18 rotates to allow sliding;
FIGS. 17A to 17D are plan views for explaining the operation of the drawing device when the sliding door gets open (FIG. 17A illustrates the drawing device when the sliding door is fully closed, FIG. 17B illustrates the drawing device when the sliding door starts to open, FIG. 17C illustrates the drawing device when the damper lock fits in the lock hole of the base, and FIG. 17D illustrates the drawing device when the damper base moves integrally with the base); and
FIGS. 18A to 18D are cross sectional views for explaining the operation of the drawing device when the sliding door gets open (FIG. 18A illustrates the drawing device when the sliding door is fully closed, FIG. 18B illustrates the drawing device when the sliding door starts to open, FIG. 18C illustrates the drawing device when the damper lock fits in the lock hole of the base, and FIG. 18D illustrates the drawing device when the damper base moves integrally with the base).



DETAILED DESCRIPTION OF THE INVENTION
With reference to the drawings, an exemplary embodiment of the present invention will be described below. FIGS. 1A to 1C are outline views of a drawing device. On the top frame of a sliding door 1, a guide rail 2 is fixed that extends in the moving direction of the sliding door 1. A drawing device main body 4 also elongating is inserted into the guide rail 2 and can move smoothly in the guide rail 2 by door rollers 5 and 6 which are provide at the longitudinal-direction respective ends of the drawing device main body 4. The sliding door 1 suspends from the drawing device main body 4. The drawing device main body 4 moves in the guide rail 2 in conjunction with movement in opening and closing directions of the sliding door 1. The sliding door 1 is connected to the door roller 5 via a position adjusting unit 7. The position in the vertical direction and width direction of the sliding door 1 relative to the drawing device main body 4 can be adjusted by the position adjusting unit 7.
The guide rail 2 has a trigger pin 8. This trigger pin 8 is fixed at the position where the sliding door 1 moves in the closing direction and the drawing device main body 4 starts to operate. There is a cover 9 of the drawing device main body 4 and the cover 9 has a slit 9a formed to receive the trigger pin 8 when the drawing device main body 4 moves toward the trigger pin 8.
FIGS. 2A to 2D are detail views of the guide rail 2. The guide rail 2 has an approximately rectangular cross section and is fixed to the frame by a countersunk screw 11. At the ceiling part of the guide rail 2, the trigger pin 8 is fixed projecting in the guide rail 2. At the bottom part of the guide rail 2, a slit 2a is formed the entire length of the guide rail 2 in the longitudinal direction. The door rollers 5 and 6 of the drawing device main body 4 roll on the upper surface of the bottom part of the guide rail 2. There is a connecting shaft 5a (see FIG. 1) that projects from the door rollers 5 and 6 via the slit 2a for connecting the door rollers 5 and 6 to the sliding door 1.
FIGS. 3A to 4B are detail views of the drawing device main body 4. FIGS. 3A and 3B are plan views of the drawing device main body 4 and FIGS. 4A and 4B are vertical cross sectional views of the drawing device main body 4. FIGS. 3A and 4A illustrate the drawing device main body 4 assembled and FIGS. 3B and 4B illustrate the drawing device main body 4 of which main parts are disassembled. The drawing device main body 4 has a base 12 elongating in the longitudinal direction of the guide rail 2 and a slider 14 which is slidable in the longitudinal direction relative to the base 12.
As illustrated in FIGS. 3A and 3B, the rotation axes 17, 16 of the door rollers 5 and 6 are fixed at the respective ends of the base 12 in the longitudinal direction and the door rollers 5 and 6 are rotatable on the rotation axes 17, 16. In the base 12, a pair of side walls 12a is formed at the respective sides of the base 12 in the width direction for guiding the slider 14. A pulling coil spring 15 is provided over between the base 12 and the slider 14 as an elastic member. The slider 14 slides automatically in the base 12 by a biasing force of the pulling coil spring 15.
A trigger catcher 18 is mounted in the slider 14 for catching the trigger pin 8. The trigger catcher 18 is supported at the tip end in the closing direction of a trigger pusher 19 to be rotatable in the horizontal plane. A malfunction reset cam 20 is also supported by the trigger pusher 19 to be rotatable in the horizontal plane. A locking piece 18b (FIG. 4B) and a rotation axis 18a of the trigger catcher 18 pass through an opening 20a of the malfunction reset cam 20 and fit in a trigger catcher guide groove 12b formed in the base 12 and a trigger catcher guide slit 14a formed in the slider 14 to be slidable in the longitudinal direction. There is a compression coil spring 21 provided over between the trigger pusher 19 and the slider 14.
When the sliding door 1 is open, as illustrated in FIGS. 3A and 3B, the slider 14 is positioned at the lock position at the end in the closing direction of the base 12. In an area where the slider 14 operates in the bottom surface of the base 12, a trigger catcher guide groove 12b is formed, including a straight groove 12b-1 extending in the longitudinal direction and a locking groove 12b-2 bent to one side at the end in the closing direction of the straight groove 12b-1. When the locking piece 18b of the trigger catcher 18 is fit in the locking groove 12b-2, the slider 14 is locked. The trigger pusher 19 and the compression coil spring 21 hold the state in which the locking piece 18b of the trigger catcher 18 is fit in the locking groove 12b-2 and then hold the lock position of the slider 14. The malfunction reset cam 20 is provided to return the slider 14 to the lock position even if the lock of the slider 14 is released by malfunction.
Between the paired side walls 12a of the base 12, a damper base 22 is fitted therein slidably. In the bottom part of the base 12, a pair of damper base guide grooves 12c is formed separated in the longitudinal direction. The damper base 22 has a pair of leg parts 22g formed separated in the longitudinal direction. The paired leg parts 22g are fit into the damper base guide grooves 12c. The damper base 22 slides in the base 12 in the longitudinal direction as guided by the damper base guide grooves 12c and the paired side walls 12a of the base 12.
On the damper base 22, a linear damper 24 as a first damper and a rotary damper 25 as a second damper are fixed thereto. The linear damper 24 has a tubular damper main body 24a and a rod 24b extendable relative to the damper main body 24a. When the rod 24b contracts, there is generated a damping force. The rotary damper 25 has a disc-shaped damper main body 25a and a rotation axis 25b rotatable relative to the damper main body 25a. When the rotation axis 25b rotates, there is generated a damping force. The rotation axis 25b is connected to a pinion 27 integrally.
The damper main body 24a of the linear damper 24 and the damper main body 25a of the rotary damper 25 are connected to the damper base 22. The rod 24b of the linear damper 24 is connected to the slider 14. When the slider 14 moves relatively toward the damper base 22, there is generated a damping force of the linear damper 24. There is a rack 26 provided at the opposite side of the base 12 in the closing direction of the sliding door, and the pinion 27 of the rotary damper 25 engages with the rack 26. When the damper base 22 moves relatively toward the opposite end to the closing direction of the base 12, the rotary damper 25 rotates and there occurs a damping force.
As illustrated in FIGS. 4A and 4B, at the end of the damper base 22 in the closing direction, a damper lock 28 is attached thereto to be rotatable in the vertical plane. In the base 12, a lock hole 12d is formed as a damper lock engaging piece for engagement of the damper lock 28 therein. When the damper lock 28 fits in the lock hole 12d of the base 12, the damper base 22 is locked so that the damper base 22 cannot slide in the longitudinal direction relative to the base 12. When engagement between the damper lock 28 and the lock hole 12d of the base 12 is released, the damper base 22 comes to slide in the longitudinal direction relative to the base 12.
Next description is made about the structure of each part of the drawing device main body 4.
FIGS. 5A to 5C illustrate the base 12. The elongated base 12 has both ends in the longitudinal direction where connecting pieces 12e are formed as connected to the door rollers 5 and 6. At the end in the direction opposite to the closing direction of the base 12, a wall part 12f is formed to which an end of the pulling coil spring is connected. At both sides in the width direction of the base 12, the paired side walls 12a are formed. The paired side walls 12a guide sliding of the slider 14 in the longitudinal direction relative to the base 12 and guide sliding of the damper base 22 in the longitudinal direction relative to the base 12.
At the bottom part of the base 12 at the closing direction side, the trigger catcher guide groove 12b is formed having a straight groove 12b-1 extending in the longitudinal direction and a locking groove 12b-2 that is bent to the side at the end in the closing direction of the straight groove 12b-1. At this trigger catcher guide groove 12b, the locking piece 18b and the rotation axis 18a of the trigger catcher 18 are fit therein.
At the end in the direction opposite to the closing direction of the trigger catcher guide groove 12b, a rectangular-shaped lock hole 12d is formed as a damper lock engaging piece that engages with the damper lock. The side surface 12d-1 in the direction opposite to the closing direction of the lock hole 12d is inclined in such a manner that the lock hole 12d becomes larger at the bottom of the lock hole 12d than at the top of the lock hole 12d. This is because, as illustrated in FIGS. 4A and 4B, fitting of the damper lock 28 in the lock hole 12d is secured even when the slider 14 pushes the rod 24b of the linear damper 24.
At the bottom part of the base 12, a pair of damper base guide grooves 12c is formed separated in the longitudinal direction. The damper base guide grooves 12c are provided for guiding the damper base 22. On the side wall of the base 12, a rack 26 is formed.
FIGS. 6A to 6F are detail views of the slider 14. In the slider 14, a trigger catcher guide slit 14a is formed which has a straight slit 14a-1 extending in the longitudinal direction to the closing side and a locking slit 14a-2 bent to the side at the end in the closing direction of the straight slit 14a-1.
This trigger catcher guide slit 14a corresponds to the trigger catcher guide groove 12b of the base 12 and passes through the slider 14 vertically. When the slider 14 reaches the lock position, the trigger catcher guide slit 14a and the trigger catcher guide groove 12b overlap each other. Then, the locking piece 18b of the trigger catcher 18 (see FIG. 4B) rotates in such a manner as to enter the locking groove 12b-2 of the trigger catcher guide groove 12b and the locking slit 14a-2 of the trigger catcher guide slit 14a (see FIG. 3B). As the compression coil spring 21 pushes the trigger pusher 10 in the closing direction, the locking piece 18b of the trigger catcher 18 is kept fit in the locking groove 12b-2 and the locking slit 14a-2 so that the slider 14 is maintained at the lock position.
In the slider 14, a guide bar 14c is formed for guiding the trigger pusher 19 to be slidable. In the slider 14, a projection 14d is formed which is fit inside the compression coil spring 21. At the end in the direction opposite to the closing direction of the slider 14, a connection slit 14e is formed which is connected to the tip end of the rod 24b of the linear damper 24. As illustrated in FIG. 4B, a stop ring 24c is mounted on the tip end of the rod 24b. The stop ring 24c and the slider 14 are connected to each other by fitting the stop ring 24c on the connection slit 14e. 
As illustrated in FIGS. 6A to 6E, at the end in the direction opposite to the closing direction of the slider 14, an operation piece 14f is formed that abuts to the damper lock 28 to rotate the damper lock 28 (see FIG. 15B). In the bottom surface of the slider 14, a recess 14g is formed for allowing rotation of the damper lock 28 by the operation piece 14f. 
FIGS. 7A to 7D illustrate the trigger pusher 19. At the end in the direction opposite to the closing direction of the trigger pusher 19, a projection 19a is formed that is fit inside the compression coil spring 21. At the end in the closing direction of the trigger pusher 19, a hole 19b is formed. In this hole 19b, the rotation axis 18a of the trigger catcher 18 is fit rotatably. At the bottom side of the trigger pusher 19, a guide groove 19c is formed which is guided by the guide bar 14c of the slider 14. Further, in the bottom surface of the trigger pusher 19, a projection 19d is formed that is fit in the straight groove 12b-1 of the base 12 slidably.
FIGS. 8A to 8D illustrate the trigger catcher 18. The trigger catcher 18 has a disc-shaped main body 18c, a rotation axis 18a projecting downward from the main body 18c and a locking piece 18b that is provided in adjacent to the rotation axis 18a under the main body. In an upper surface of the main body 18c, a trigger pin insert groove 18d is formed for inserting the trigger pin 8 therein. The trigger pin insert groove 18d is surrounded by a wall, in a part of which an inlet part 18e is formed for insertion of the trigger pin 8. The locking piece 18b and the rotation axis 18a of the trigger catcher 18 are fit in the trigger catcher guide groove 12b of the base 12.
FIGS. 9A to 9C illustrate the malfunction reset cam 20. Once it is fit in the trigger catcher 18, the malfunction reset cam 20 is supported rotatably, with the trigger catcher 18, by the trigger pusher 19. In the malfunction reset cam 20, a sector-shaped opening 20a is formed in which the locking piece 18b and the rotation axis 18a of the trigger catcher 18 are fit. This sector-shaped opening 20a is formed larger than the locking piece 18b and the rotation axis 18a of the trigger catcher 18 in such a manner that rotation of the trigger catcher 18 relative to the malfunction reset cam 20 can be allowed. At the end in the closing direction of the malfunction reset cam 20, a slit 20b is formed so that the malfunction reset cam 20 is branched into two vertically. On an upper piece 20c, a locking piece 20d is formed so as to catch the trigger pin 8.
When the slider 14 is away from the lock position due to malfunction, the inlet 18e of the trigger pin insert groove 18d of the trigger catcher 18 cannot accommodate the trigger pin 8. Therefore, even if the sliding door 1 is moved in the closing direction and the slider 14 is close to the trigger pin 8, the trigger catcher 18 cannot catch the trigger pin 8. Even in such a case, the upper piece 20c of the malfunction reset cam 20 is bent so that the locking piece 20d of the upper piece 20c catches the trigger pin 8. Therefore, the slider 14 can be reset to the lock position.
FIGS. 10A to 10D illustrate the damper base 22. The damper base 22 has a linear damper fixing part 22a where the damper main body of the linear damper 24 is mounted, a damper lock connection bracket 22c provided at the end in the closing direction of the linear damper fixing part 22a and a plate-shaped rotary damper fixing part 22b where the damper main body 25a of the rotary damper 25 is fixed at the side in the direction opposite to the closing direction of the linear damper fixing part 22a. 
At both ends in the width direction of the linear damper fixing part 22a, a pair of claws 22d is provided bent inward. The damper main body 24a of the linear damper 24 is sandwiched between the paired claws 22d in the width direction. At respective ends in the longitudinal direction of the linear damper fixing part 22a, a pair of end walls 22e is formed between which the damper main body 24a is sandwiched in the longitudinal direction. The damper lock connection bracket 22c projects from the linear damper fixing part 22a in the closing direction. Connected to the damper lock connection bracket 22c is the damper lock 28 via a spring pin rotatably. The damper lock 28 is biased to the lock hole 12d of the base by the spring pin. At the bottom of the plate-shaped rotary damper fixing part 22b, a positioning projection 22f is formed for positioning the damper main body 25a of the rotary damper 25.
FIGS. 11A to 11C illustrate the damper lock 28. The damper lock 28 has a through hole 28a formed, into which a spring pin is inserted for connecting the damper lock 28 to the damper base 22. The damper lock 28 rotates in the vertical plane around the through hole 28a as a seesaw. On the upper surface at the end in the closing direction of the damper lock 28, a slider side hook 28b is formed which engages with a side 14g-1 in an opposite direction to the closing direction of the recess 14g of the slider 14 (see FIG. 6D). In the lower-side center part of the damper lock 28 in the longitudinal direction, a base side hook 28c is formed that engages with a side 12d-1 in an opposite direction to the closing direction of the lock hole 12d of the base 12 (see FIG. 5C).
FIG. 12 illustrates the linear damper 24. The linear damper 24 has the tubular damper main body 24a and the rod 24b that is extendable relative to the damper main body 24a. In the damper main body 24a, a piston (not shown) is provided to be connected to the rod 24b. The damper main body 24a is filled with oil. With extension and contraction of the rod 24b, the piston moves in the damper main body and viscous resistance of the oil causes a damping force. The piston sometimes has an orifice for passage of the oil.
FIGS. 13A to 13C illustrate the rotary damper 25. The rotary damper 25 has the disc-shaped damper main body 25a, the rotation axis 25b rotatable relative to the damper main body 25a and the pinion 27 connected to the rotation axis 25b. The damper main body 25a is filled with oil. The rotation axis 25b is connected to the rotor (not shown) . When the rotor rotates in the damper main body 25a, viscous resistance of the oil causes a damping force. In the damper main body 25a, a pair of overhanging parts 25c is formed which are connected to the damper base 22.
Next description is made about the operation of the drawing device when the sliding door 1 gets closed. FIGS. 14A to 14C are plan views of the drawing device and FIGS. 15A to 15C are cross sectional views of the drawing device. FIGS. 14A and 15A illustrate the drawing device which starts to draw, FIGS. 14B and 15B illustrate the drawing device when the dampers are changed, and FIGS. 14C and 15C illustrate the drawing device when the door is closed fully.
When the sliding door 1 is moved in the closing direction manually, the drawing device main body 4 moves in the closing direction together with the sliding door 1. As illustrated in FIGS. 14A and 15A, when the slider 14 reaches the drawing start position, the trigger catcher 18 abuts to the trigger pin 8. Then, the trigger catcher 18 rotates to catch the trigger pin 8, the slider 14 becomes slidable relative to the base 12. As the pulling coil spring 15 is provided between the slider 14 and the base 12, it causes such a pulling force as to slide the slider 14. As the trigger catcher 18 catches the trigger pin 8 fixed to the guide rail 2, the base 12 moves in the closing direction without moving the trigger catcher 18.
With movement of the base 12 in the closing direction, the sliding door 1 starts to move in the closing direction, and therefore, the force for closing the sliding door 1 is reduced. Then, as the rod 24b moves in the direction of the damper main body 24a of the linear damper 24, there occurs a larger damping force by the linear damper 24. As the linear damper 24 operates at the initial operation time where the spring force of the pulling coil spring 15 is large and the larger damping force is generated, movement of the sliding door 1 can be smoothed.
FIGS. 16(1-1) to (4-2) are detail views in which the trigger catcher 18 rotates to allow sliding. FIGS. 16(1-2) (2-2), (3-2), (4-2) illustrate the trigger catcher 18 before it rotates and FIGS. 16(1-1) (2-1), (3-1), (4-1) illustrate the trigger catcher 18 after it has rotated. FIGS. 16(1-1) and (1-2) at the top stage are plan views of the trigger pin 8 and the trigger catcher 18, FIGS. 16(2-1) and (2-2) at the second stage from the above are plan views of the trigger catcher 18, FIGS. 16(3-1) and (3-2) at the third stage from the above illustrate a state where the trigger catcher 18 is removed and FIGS. 16(4-1) and (4-2) at the bottom stage illustrate a state where the trigger catcher 18 and the malfunction reset cam 20 are removed.
As illustrated in FIGS. 16(1-1) and (1-2), when the trigger pin 8 abuts to the trigger catcher 18, the trigger catcher 18 rotates.
As illustrated in FIGS. 16(2-1) and (2-2), with rotation of the trigger catcher 18, the locking piece 18b of the trigger catcher 18 gets out of the locking groove 12b-2 of the base 12 and the locking slit 14a-2 of the slider 14.
As illustrated in FIGS. 16(3-1) and (3-2), with rotation of the trigger catcher 18, the malfunction reset cam 20 rotates. The open angle of the sector-shaped opening 20a of the malfunction reset cam 20 is larger than the locking piece 18b, the rotation angle of the malfunction reset cam 20 becomes smaller than the trigger catcher 18. Accordingly, if the malfunction reset cam 20 rotates, it does not run off the slider 14.
As illustrated in FIGS. 16(4-1) and (4-2), with rotation of the trigger catcher 18, the trigger pusher 19 that supports the rotation axis 18a of the trigger catcher 18 goes back to the direction opposite to the closing direction and shortens the compression coil spring 21.
Returning to FIGS. 14B and 15B, when the base 12 reaches the damper switching position, the rod 24b is accommodated in the damper main body 24a completely and the damping force due to the linear damper 24 disappears. At the same time, the slider 14 rotates the damper lock 28 against the spring force of the spring pin and engagement between the damper lock 28 and the base 12 is released. The rotated damper lock 28 enters the recess 14g of the slider 14 and the base 12 starts to move in the closing direction of the sliding door 1 relative to the damper base 22. At the end of the damper base 22 in the direction opposite to the closing direction, the rotary damper 25 is provided. Therefore, the rack 26 provided in the base 12 and the pinion 27 of the rotary damper 25 engage with each other, and the rotary damper 25 rotates. The rotation of the rotary damper 25 causes a damping force. Even after the operation of the linear damper 24, it is switched to the rotary damper 25 and the rotary damper 25 causes a damping force until the sliding door 1 is closed fully. This makes it possible to prevent occurrence of impact and noise during the full closing operation. As the pulling force of the pulling coil spring 15 becomes small at a last half of the drawing operation, it does not matter if the damping force generated by the rotary damper 25 is small.
Finally, as illustrated in FIGS. 14C and 15C, the sliding door is fully closed.
Next description is made about the operation of the drawing device when the sliding door opens. FIGS. 17A to 17D are plan views of the drawing device and FIGS. 18A to 18D are cross sectional views of the drawing device. FIGS. 17A and 18A illustrate the drawing device when the sliding door is fully, closed, FIGS. 17B and 18B illustrate the drawing device when the sliding door starts to open, FIGS. 17C and 18C illustrate the drawing device when the damper lock is fit in the lock hole of the base 12 and FIGS. 17D and 18D illustrate the drawing device when the damper base 22 moves integrally with the base 12.
As illustrated in FIGS. 17A and 18A, when the sliding door 1 is fully closed, the damper lock 28 is fit in the recess 14g of the slider 14 and the base 12 can move relative to the slider 14 with movement of the sliding door 1.
As illustrated in FIG. 18B, when the sliding door 1 starts to open, the slider side hook 28b of the damper lock 28 engages with the recess 14g of the slider 14, and the base 12 moves in the opening direction relative to the damper base 22 and the slider 14. Then, the pinion 27f the rotary damper 25 rotates while it engages with the rack 26 provided in the base 12. As the rotary damper 25 is set not to cause the damping force in the rotational direction when the sliding door 1 opens, the load applied when opening the sliding door 1 is only an elastic force that is generated by extending of the pulling coil spring 15.
As illustrated in FIG. 18C, when the lock hole 12d of the base 12 moves to the damper lock position, the base side hook 28c of the damper lock 28 is fit in the lock hole 12d by the spring force of the spring pin and the damper base 22 moves integrally with the base 12. As the base 12 moves in the opening direction of the sliding door 1, the rod 24b is drawn from the damper main body 24a of the linear damper 24.
As illustrated in FIGS. 17D and 18D, the rod 24b is completely drawn from the damper main body 24a of the linear damper 24 and the slider 14 moves up to the lock position of the base 12, the trigger catcher 18 and the malfunction reset cam 20 rotate by the elastic force of the compression coil spring 21 and the slider 14 is fixed to the lock position. Then, as the trigger catcher 18 releases the trigger pin 8, the sliding door is moved without operating of the drawing device.
The present invention is not limited to the above-described embodiments but may be modified in various forms without departing from the scope of the present invention. For example, the drawing device of the present invention may be used to assist closing and opening of the opening/closing body such as folding door, drawer, as well as the sliding door. Besides, in the above-mentioned embodiment, the linear damper is used as a first damper and the rotary damper is used as a second damper. However, the first and second dampers may be linear dampers of different damping forces or rotary dampers of different damping forces. Further, in the above-mentioned embodiment, the trigger catcher and the slider are separate members, but they may be combined into one piece.
The present invention is not limited to the above described embodiments, and various variations and modifications may be possible without departing from the scope of the present invention.
This application is based on the Japanese Patent application No. 2010-038302 filed on Feb. 24, 2010 to which the instant Application claims priority as set forth in the Application Data Sheet.

## Claims

1. A drawing device for imposing a biasing force in one direction to an opening/closing body movable relative to a frame when the opening/closing body moves in the one direction, comprising:
a trigger pin which is attached to one of the frame and the opening/closing body; and
a drawing device main body which is attached to an other of the frame and the opening/closing body and provided for catching the trigger pin to provide the opening/closing body the biasing force in the one direction, the drawing device main body having
a base which is attached to the other of the frame and the opening/closing body and elongated in a moving direction of the opening/closing body,
a slider which has a trigger catcher capable of catching the trigger pin and is slidable relative to the base in a longitudinal direction while the trigger catcher catches the trigger pin,
an elastic member which spans the base to the slider, provides the biasing force so as to move the slider relative to the base in the longitudinal direction and thereby imposes the biasing force in the one direction to the opening/closing body, and
a damper mechanism which generates a damping force against the slider moving relative to the base in the longitudinal direction by the biasing force of the elastic member, the damper mechanism having
a first damper and a second damper as damper sources each for generating the damping force,
a damper base which is provided in the base to be slidable in the longitudinal direction and
a damper lock which is provided in the damper base, and which engages with the base so as to prevent the damper base from sliding relative to the base in the longitudinal direction and releases engagement with the base so as to make the damper base slidable relative to the base in the longitudinal direction,


wherein when the slider moves relative to the base in the longitudinal direction by the biasing force of the elastic member, first the damper base engaging with the base by the damper lock moves relative to the slider thereby the first damper generating the damping force, and then, the damper lock and the base are disengaged and the base moves relative to the damper base and the slider, thereby the second damper generating the damping force.

2. The drawing device of claim 1, wherein the damper lock is provided in the damper base to be rotatable, a damper lock engaging piece is formed in the base that engages with the damper lock, when the slider moves relative to the base in the longitudinal direction by the biasing force of the elastic member, the slider rotates the damper lock which is in engagement with the damper lock engaging piece, and thereby the damper lock and the base are disengaged.

3. The drawing device of claim 2, wherein the damping force generated by the first damper is larger than the damping force generated by the second damper.

4. The drawing device of claim 1, wherein the damping force generated by the first damper is larger than the damping force generated by the second damper.