Bidirectional retraction device for sliding doors

Abstract

To make it possible to cope with a wide weight range of a sliding door, obtain a long braking distance, and reduce a product cost.SOLUTION: A bidirectional sliding door retractor 1 of a sliding door 2 is configured such that: a piston type damper 14 is arranged in a case 10 in which a guide part 10a is formed on either side wall and a temporary stop part K is formed at either end part of the guide part 10a; sliders 18, 19 having engaging parts 18a, 19a engaged with the guide part 10a or the temporary stop part K are rotatably connected to a door head side end part and a door tail side end part of the piston type damper 14, respectively; and concurrently, the sliders 18, 19 are provided with energizing force in the retraction direction by a spring member 17, and at least one slider 18 (19) is locked to the temporary stop part K of the case 10. The piston-type damper 14 is made up of two piston-type dampers 14a, 14b connected in series via an intermediate connecting member 20.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a bidirectional retraction device for a sliding door that is capable of retracting a sliding door to a fully closed position and a fully open position when the sliding door is closed and opened, respectively. [Background technology]

[0002] Conventionally, for hanging doors (hanging sliding doors) in which a wheel-type runner device fixed to the upper end of the sliding door runs along a guide rail fixed to the lintel of the door frame, and for sliding doors in which a wheel fixed to the lower end of the sliding door runs along a wheel guide rail, various retraction devices for sliding doors have been proposed that automatically retract the door to the closed position and close it after closing it to a specified position from an open state.

[0003] For example, in the following Patent Document 1, as shown in FIG. 11, a slider 52 is provided in a case 50 so as to be slidable along the opening and closing direction of the sliding door, has an engaging protrusion 52a that engages with a slide guide groove 51a formed in the case 50, and has an upper end that protrudes from the case 50 and is in a relationship in which it can be engaged with and disengaged from the engaging pin 55, a piston-type damper 53 is provided in the case 50 with a piston tip connected to the slider 52, and a spring member 54, one end of which is engaged with the slider 52 and the other end of which is engaged with the case 50, and which applies a biasing force to the slider 52 in the direction in which the sliding door is retracted, A temporary stop portion K consisting of a bent guide groove 51b is formed continuously from the slide guide groove 51a on the sliding door end side of the slide guide groove 51a, The slider 52 is provided with a tip-side engagement piece 52b which engages with the engagement pin 55 when the sliding door is opened, and moves the slider 52 toward the sliding door end against the biasing force of the spring member 54, and at the sliding door end side of the slide guide groove 51a, the engagement protrusion 52a of the slider 52 is guided toward the curved guide groove 51b, causing the slider 52 to swing and be in a temporary stopped state, and thereby disengages from the engagement pin 55. The slider 52 is provided with a base-side engagement piece 52c which engages with the engagement pin 55 when the sliding door is closed, and causes the slider 52, which is in the temporary stopped state, to swing and release the temporary stopped state, thereby engaging the tip-side engagement piece 52b with the engagement pin 55. A retraction device main body is disclosed in which, when the sliding door is closed, the sliding door is retracted to the closed position by the biasing force of the spring member 54 while receiving the braking force of the piston-type damper 53.

[0004] The above-mentioned retraction device retracts the sliding door in the closing direction, but for single-sided sliding doors, a bidirectional retraction device has been proposed that enables the sliding door to be retracted in both the closing direction and the opening direction.

[0005] For example, the following Patent Document 2 discloses a door closing device which comprises a rod-shaped casing having locking grooves on both longitudinal ends, a cushioning damper consisting of a cylinder section and a piston rod, hook members journalled on the base end of the cylinder section and the tip of the piston rod, respectively, and a tensile elastic body provided between the opposing hook members, with at least one of the hook members being locked in the locking groove of the rod-shaped casing.

[0006] According to the retraction device of Patent Document 2 mentioned above, in contrast to the conventional type that required separate retraction devices in both the closing and opening directions of the sliding door, a single retraction device can be used to retract the door in both the closing and opening directions, which provides advantages such as the device being compact, being easily installed in a small space, and being inexpensive due to the simple configuration. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2012-149438 A [Patent Document 2] JP 2009-287355 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the case of the bidirectional retractable device described in Patent Document 2, hook members are provided at the base end of the cylinder and the tip of the piston rod for one damper, so in order to accommodate doors ranging from light to heavy, it was necessary to prepare in advance multiple types of dampers that could handle the impact force according to the weight of the sliding door. Also, if it was desired to extend the range (stroke) over which the damping force of the damper was effective, it was necessary to manufacture a special damper with a long stroke, which was a factor in increasing costs. Furthermore, it was necessary to prepare multiple sizes of cases to store the dampers according to their sizes.

[0009] In addition, the heavier the sliding door, the more powerful the damper that is used. However, in the case of a bidirectional retractable device that uses a single damper, the durability against the repeated opening and closing of the sliding door tends to be low.

[0010] SUMMARY OF THE PRESENT EMBODIMENTS The main object of the present invention is to provide a bidirectional retraction device for a sliding door which is adaptable to a wide range of sliding door weights, provides a long braking distance, and has low manufacturing costs. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention according to claim 1 provides a bidirectional retraction device for a sliding door, in which a piston-type damper is disposed within a case having guide sections formed on both side walls and having temporary stops formed on both ends of the guide sections, and a slider is rotatably connected to the piston-type damper, which has engagement sections at both ends of the leading end and trailing end of the piston-type damper that engage with the guide sections or temporary stops and which is capable of engaging with and disengaging from an engagement pin provided on the door frame or rail, and a spring member is applied to the slider in the retraction direction, and at least one of the sliders is engaged with the temporary stops of the case, The piston-type damper comprises two piston-type dampers connected in series via an intermediate connecting member. A cylinder holder is attached to each of the two piston-type dampers, the cylinder holder is provided so as to be slidable along the case, and the intermediate connecting member is provided so as to be slidable along the case. A bidirectional retraction device for a sliding door is provided.

[0012] In the invention described in claim 1, in the bidirectional retraction device for a sliding door, the piston-type damper is two piston-type dampers connected in series via an intermediate connecting member. a cylinder holder is attached to each of the two piston-type dampers, the cylinder holder is provided so as to be slidable along the case, and the intermediate connecting member is provided so as to be slidable along the case. Therefore, even if the output of each piston damper is small, by combining two piston dampers, it is possible to handle heavy sliding doors. In addition, because two piston dampers are connected in series, the braking distance is almost twice as long as that of a single piston damper, and a long braking distance can be obtained. In addition, since it is possible to use a highly versatile standard damper instead of a special heavy-duty or long-stroke damper, the product cost can be reduced.

[0013] According to a second aspect of the present invention, there is provided a bidirectional retraction device for a sliding door as described in the first aspect, wherein the spring member is provided between the slider and the intermediate connecting member.

[0014] The invention described in claim 2 above prescribes the arrangement of the spring member that retracts the slider. Effect of the Invention

[0015] As explained above in detail, according to the present invention, it is possible to accommodate a wide range of sliding door weights, obtain a long braking distance, and reduce the manufacturing cost. [Brief description of the drawings]

[0016] [Figure 1] 1 is a front view of a hanging sliding door 2 to which a bidirectional retracting device 1 according to the present invention is applied. [Diagram 2] FIG. 2 is an exploded view of the bidirectional retraction device 1 and the hoist-type runner device 7. [Diagram 3] FIG. 1 is a perspective view of a bidirectional retraction device 1. [Figure 4] 1A is an exploded view of the bidirectional retraction device 1, and FIG. 1B is an enlarged view of the end of the case middle part 11. FIG. [Diagram 5] FIG. 2 is a side view of the retraction device unit 9. [Figure 6] FIG. 2 is an exploded view of the retraction device unit 9. [Figure 7] 1A shows an intermediate connecting member 20, in which (A) is a side view, (B) is an end view, and (C) is a bottom view. [Figure 8] FIG. 2 is a perspective view of an intermediate connecting member 20. [Figure 9] FIG. 1 is a procedural diagram showing retraction procedures (A) to (C). [Figure 10] FIG. 2 is a side view showing the stroke of the bidirectional retraction device 1. [Figure 11] FIG. 13 is an enlarged side view of a main portion showing a conventional retraction device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0018] [Structure of bidirectional retraction device 1] 1 is a suspended sliding door in which an opening frame is provided by an upper rail 3, side frames 5A, 5B, and a lower rail 6, and in which suspension wheel type runner devices 7, 8 are disposed to run within the upper rail 3, and which is suspended by these suspension wheel type runner devices 7, 8, allowing the door to move freely along the upper rail 3. The suspended sliding door 2 is designed so that a lower pivot 29 runs along the lower rail 6 so that the lower end of the sliding door does not swing when running.

[0019] As shown in FIG. 2, a U-shaped notch 2a is provided at both ends of the upper portion of the sliding door 2 when viewed from the front. A fixing base 28 is fitted into this notch 2a and fixed by a screw 30.

[0020] The suspension wheel type runner devices 7, 8 are attached to the fixing base 28 in a one-touch manner. To explain in detail the suspension wheel type runner device 7, which is typically arranged on the door end side, the suspension wheel type runner device 7 is composed of a runner body 7A and a runner attachment 7B, which are connected by a vertically oriented shaft member. The runner body 7A has two rollers 32 supported by roller shafts on each side of the roller support body 31, and these rollers 32, 32... roll in the running grooves 3b, 3b of the upper rail 3, allowing it to move freely along the upper rail 3. The suspension wheel type runner device 8 on the door tail side has a similar structure.

[0021] The upper rail 3 can be a guide rail used for a general sliding door, and no special rail is required. As shown in FIG. 2, the upper rail 2 has a slit formed in the center of the lower surface, and running grooves 3b, 3b in which rollers 32, 32... can roll are formed on both sides of the slit. The upper rail 2 is fixed to the lintel of the door frame by fixing screws inserted into a plurality of through holes provided on the ceiling surface. In addition, an engagement pin 4A is arranged at a predetermined position on the ceiling surface of the upper rail 3, with which the bidirectional retraction device 1 engages when the sliding door 2 is closed, and an engagement pin 4B is arranged with which the bidirectional retraction device 1 engages when the sliding door 2 is opened.

[0022] Of the two hoist type runner devices 7 and 8, the bidirectional retraction device 1 is connected to the runner body 7A of the hoist type runner device 7 on the door end side. As shown in Fig. 2, a roller 33 is provided on the other end side of this bidirectional retraction device 1, and the device moves on the upper rail 3 integrally with the sliding door 2. When the sliding door 2 is closed or opened, the sliding door 2 is automatically retracted to the fully closed or fully open position.

[0023] The bidirectional retraction device 1 will now be described in detail.

[0024] As shown in Figures 3 and 4, the bidirectional retraction device 1 has a piston-type damper 14 disposed within a case 10 having guide portions 10a formed on both side walls and temporary stop portions K formed continuous with both ends of the guide portions 10a, and the piston-type damper 14 has engagement portions 18a, 19a at its leading end and trailing end that engage with the guide portions 10a and temporary stop portions K, respectively, and is rotatably connected to sliders 18, 19 which are capable of engaging with and disengaging from an engagement pin 4A (4B) provided on the door frame or rail side. A spring member 17 is applied to the sliders 18, 19 in the retraction direction, and at least one of the sliders 18 (19) is engaged with the temporary stop portion K of the case 10.

[0025] In particular, in the present invention, the piston-type damper 14 is composed of two piston-type dampers 14A and 14B connected in series via an intermediate connecting member 20.

[0026] More specifically, As shown in Figures 3 and 4, the case 10 has guide portions 10a formed on both side walls, and temporary stop portions K are formed continuously with both ends of the guide portions 10a. The guide portions 10a may have any shape as long as they can be engaged with the engagement portions 18a, 19a provided on the sliders 18, 19, but it is particularly preferable that they be formed as slide guide grooves as in the illustrated example. Similarly, the temporary stop portions K may have any shape as long as they can be engaged with the engagement portions 18a, 19a of the sliders 18, 19, but it is particularly preferable that they be formed as bent guide grooves 10b that are bent downward in an L-shape as in the illustrated example.

[0027] As shown in Figure 4(B), on both sides (upper and lower) of the guide portion 10a consisting of a slide guide groove, convex ribs 10c, 10c are formed which protrude toward the inside of the case 10 and extend continuously over almost the entire length of the guide portion 10a.

[0028] 4, the case 10 is constructed by assembling three parts, namely, a case middle part 11 having guide parts 10a formed on both side walls, and left and right case end parts 12, 13 having ends of the guide parts 10a and temporary stop parts K continuous therewith. Note that multiple types of case middle part 11 having different lengths may be prepared.

[0029] The end (door end side) of the case middle part 11 is L-shaped in side view, and a through hole 11b is formed in the lower protruding piece 11a. A guide part 10a consisting of a slide guide groove with a groove-shaped cross section that opens inward is formed in the middle of the height direction of the side wall, and a plate-shaped clamped part 11c is formed at the top and bottom of the guide part 10a.

[0030] On the other hand, the case end 12 is formed with the end of the guide portion 10a and a temporary stop portion K continuous therewith, and on the connection side with the case middle portion 11, it has a clamping portion 12a with a gap capable of clamping the clamped portion 11c of the case middle portion 11, and at the bottom it has an engagement support portion 12b with which the protruding piece 11a of the case middle portion 11 is combined in an engaged state, and the engagement support portion 12b has a through hole.

[0031] Then, after the case middle portion 11 and the case end portion 12 are fitted together so that they are butted against each other, a rivet 34 (or a screw) is passed through the through hole 11b of the protruding piece 11a and the through hole of the fitting support portion 12b to firmly connect the two together.

[0032] The connection between the case middle part 11 and the case end part 13 on the door tail side has an exactly similar structure, and once the two are butted together and fitted together, rivets 34 (or screws) are passed through the through holes to firmly connect the two.

[0033] Of the case 10 which is composed of three components, the case middle portion 11 and the left and right case end portions 12 and 13, by preparing multiple types of case middle portion 11 with different lengths, it is possible to change the length of case 10 while standardizing the parts.

[0034] 5 and 6, the case 10 is provided with a retraction device unit 9 in which sliders 18, 19 are rotatably connected to the leading end and trailing end of the piston damper 14, the engaging portions 18a, 19a engaging with the guide portion 10a and the temporary stop portion K, and which are engaged with and disengaged from engaging pins 4A, 4B provided on the door frame or rail, and to which a spring member 17 applies a biasing force in the retracting direction to the sliders 18, 19. The engaging portions 18a, 19a provided on the sliders 18, 19 may be of any shape as long as they can engage with the guide portion 10a provided on the case 10, but it is particularly preferable that they be engaging protrusions that can engage with the slide guide groove as in the illustrated example.

[0035] The piston damper 14 is composed of two piston dampers 14A, 14B connected in series via an intermediate connecting member 20. That is, the piston damper 14A is disposed on the door leading side of the sliding door 2, and the piston damper 14B is disposed on the door trailing side, and these piston dampers 14A, 14B are connected by the intermediate connecting member 20.

[0036] The two piston-type dampers 14A, 14B may have the same output of the damping force and / or stroke length, or may be combined with those having different outputs. When the two piston-type dampers 14A, 14B have the same damping force, they contract at approximately the same speed, and when they have different damping forces, the piston-type damper with the smaller damping force contracts first, followed by the piston-type damper with the larger damping force.

[0037] Each piston-type damper 14A, 14B is composed of a piston 15 and a cylinder 16, with a viscous material (such as silicone oil) sealed inside the cylinder 16. When the piston 15 moves inside the cylinder 16, the movement of the viscous material generates a resistance force (damping force) according to the speed of movement, thereby absorbing energy.

[0038] As shown in Figures 5 and 6, the slider 18 has an engagement portion 18a on its side that engages with the guide portion 10a and the temporary stop portion K, a connecting shaft portion 18b at its base end, a pin engagement portion 18c at its top, and a spring connection portion 18d at its bottom. The slider 19 on the trailing edge side is also line-symmetrical and has the same structure. Therefore, only the reference numerals are used to follow the slider 18, and a description thereof will be omitted.

[0039] As shown in Fig. 6, a cylinder holder 21 is attached to each of the piston dampers 14A and 14B. The cylinder holder 21 is composed of an end side holder 22 provided on the end side of the piston dampers 14A and 14B, a piston side holder 23 provided on the piston side, and a connecting plate 24 connecting these.

[0040] The end side holder 22 is a member having a cylinder fitting portion 22b into which the tip of the cylinder 16 is fitted at the base end side (cylinder side) of a block-shaped main body 22a, a connecting shaft portion 22c to which the sliders 18, 19 are connected at the tip side on the opposite side, and a recessed groove 22d on each of both side portions that can be fitted into the outside of a pair of upper and lower protrusions 10c, 10c formed on the inner surface of the case 10. The connection with the sliders 18, 19 is performed by passing an axis member 25 through the connecting shaft portions 18b or 19b and 22c and crimping them. Therefore, the sliders 18, 19 are connected to the piston-type damper 14 so as to be rotatable around a horizontal axis.

[0041] The piston side retainer 23 is a member having a cylinder fitting portion 23b into which the piston side end portion of the cylinder 16 is fitted at the base end side (cylinder side) of the block-shaped main body 23a, and having grooves 23c on both side portions which can fit into the outsides of a pair of upper and lower protrusions 10c, 10c formed on the inner surface of the case 10.

[0042] To attach the cylinder holder 21 to the piston-type dampers 14A, 14B, the end side holder 22 is attached to the tip of the cylinder 16, the piston side holder 23 is attached to the piston side of the cylinder 16, and a connecting plate 24 connecting the end side holder 22 and the piston side holder 23 is fixed with screws 24a, 24b.

[0043] The cylinder retainer 21 is slidably mounted along the case 10 with the recessed grooves 22d, 23c provided on both side surfaces of the end side retainer 22 and the piston side retainer 23 respectively fitting into the outside of the protruding strips 10c, 10c of the case 10.

[0044] 7 and 8, the intermediate connecting member 20 connecting the two piston-type dampers 14A and 14B has U-shaped piston fitting portions 20b that open on one side and into which the tip of the piston 15 can be fitted at both ends of a block-shaped main body 20a, has grooves 20c on both side surfaces that can be fitted to the outsides of the upper and lower pairs of convex stripes 10c, 10c formed on the inner surface of the case 10, and has spring connecting portions 20d at both ends of the lower surface. The piston 15 is fitted into the piston fitting portion 20b by fitting the tip of the piston 15 into the circumferential groove 15a (see FIG. 6) provided at the tip of the piston 15 into the convex portion 20e formed on the inner surface of the piston fitting portion 20b.

[0045] The intermediate connecting member 20 is provided slidably along the case 10 with the concave grooves 20c provided on both side surfaces thereof fitting into the outer sides of the convex strips 10c, 10c of the case 10.

[0046] The spring member 17 is composed of two spring members: a spring member 17A on one side suspended between the spring connecting portion 18d of the slider 18 and the spring connecting portion 20d on one side of the intermediate connecting member 20, and a spring member 17B on the other side suspended between the spring connecting portion 19d of the slider 19 and the spring connecting portion 20d on the other side of the intermediate connecting member 20. Note that the spring connecting portion 20d may not be provided at the lower portion of the intermediate connecting member 20, and a single spring member may be suspended between the spring connecting portion 18d of the slider 18 and the spring connecting portion 19d of the slider 19.

[0047] The retraction device unit 9 may also be made changeable in length in response to a change in the length of the case 10. Specifically, the piston-type damper 14 and the spring member 17 (and the connecting plate 24) may be prepared in a plurality of types having different lengths corresponding to the length of the case 10, and the length of the bidirectional retraction device 1 may be made changeable by changing the length of the case intermediate portion 11 and the lengths of the piston-type damper 14 and the spring member 17.

[0048] [Explanation of the operation of the bidirectional retraction device 1] (When sliding door 2 is closed) As shown in Fig. 9(A), when the sliding door 2 is closed, the slider 18 on the door end side, which is in a temporarily stopped state, collides with the engagement pin 4A, causing the slider 18 to swing and release the temporarily stopped state. As a result, the slider 18 is brought into engagement with the engagement pin 4A, as shown in Fig. 9(B). Then, the sliding door 2 is pulled to the fully closed position by the biasing force of the spring members 17A and 17B while receiving the braking force of the piston dampers 14A and 14B (Fig. 9(C)). When the sliding door 2 is closed by the biasing force of the spring members 17A and 17B, if the two piston dampers 14A and 14B have the same output, the two piston dampers 14A and 14B contract simultaneously at approximately the same speed.

[0049] (When sliding door 2 is opened) Next, an explanation will be given of the operation state when the sliding door 2 is opened from the fully closed state. This operation is the reverse operation of the closing operation (in the order from FIG. 9(C) to FIG. 9(A)).

[0050] When the sliding door 2 is opened from its fully closed state (FIG. 9(C)), the slider 18 engaged with the engagement pin 4A moves toward the door end against the biasing force of the spring member 17A as shown in FIG. 9(B). Then, as shown in FIG. 9(A), when the engagement portion 18a of the slider 18 is guided to the curved guide groove 10b, the slider 18 swings and becomes locked in the temporary stop position K. Accordingly, the engagement between the slider 18 and the engagement pin 4A is released.

[0051] After that, when the opening operation is continued, the slider 19 on the door tail side, which is in a temporarily stopped state, hits the engagement pin 4B, causing the slider 19 to swing and release the temporarily stopped state. This brings the slider 19 into engagement with the engagement pin 4B. Then, while receiving the braking force from the piston-type dampers 14A and 14B, the sliding door 2 is pulled to the fully open position by the biasing force of the spring members 17A and 17B.

[0052] As can be seen from the above description, in the bidirectional retraction device 1, of the pair of left and right sliders 18, 19, at least one slider 18 (19) is locked to the temporary stop portion K of the case 10. Specifically, in an intermediate operation state (retraction not yet activated state) in which both sliders 18, 19 are positioned between the engagement pins 4A, 4B, both sliders 18, 19 are locked to the temporary stop portion K, and in a state in which one of the sliders 18, 19 is locked to the engagement pin 4A (4B) and retracted to the fully closed side or the fully open side, one of the sliders 18, 19 is locked to the temporary stop portion K.

[0053] In the bidirectional retraction device 1 of the present invention, the piston damper 14 consists of two piston dampers 14A, 14B connected in series via an intermediate connecting member 20. Therefore, even if the output of each piston damper 14A, 14B is small, by combining the two piston dampers 14A, 14B, it is possible to accommodate a heavy sliding door 2.

[0054] In addition, as shown in Fig. 10, two piston-type dampers 14A, 14B are connected in series, so the braking distance is approximately doubled compared to a single piston-type damper, and a long braking distance can be obtained. That is, the total stroke L is approximately twice the stroke (AB) of one damper between the positions of sliders 18, 19 in the fully closed state of the sliding door 2 shown in Fig. 10(A) and the mid-operation state (retraction not yet activated state) in which both sliders 18, 19 are in a temporary stop state shown in Fig. 10(B).

[0055] In addition, by using a versatile standard damper instead of a special damper for heavy weight or long stroke, it can accommodate heavy sliding doors and long braking distances, thereby reducing product costs.

[0056] [Other examples] (1) In the above embodiment, an example of a suspended sliding door in which the sliding door 2 is suspended by wheel-type runner devices 7, 8 running within the upper rail 3 is shown. However, in the case of a sliding door that is movable by wheels provided on the underside of the sliding door, the wheel-type runner device 7 and roller 33 that are integrally connected to the bidirectional retraction device 1, as well as the wheel-type runner device 8 on the other end side, are not required.

[0057] (2) In the above embodiment, the two piston-type dampers 14A, 14B are connected in series with the pistons 15 facing each other, but they may be connected with the cylinders 16 facing each other, or with the piston 15 and the cylinder 16 facing each other. When connecting the cylinders 16 facing each other or the piston 15 and the cylinder 16 facing each other, the cylinder holder 21 that holds at least one of the cylinders 16 may also serve as the intermediate connecting member 20 that connects the piston-type dampers 14A, 14B. [Explanation of symbols]

[0058] Reference Signs List 1...Bidirectional retraction device, 2...Sliding door, 3...Upper rail, 4A, 4B...Engagement pin, 5A, 5B...Side frame, 6...Lower rail, 7, 8...Hanging wheel type runner device, 9...Retraction device unit, 10...Case, 11...Case middle part, 12, 13...Case end, 14, 14A, 14B...Piston type damper, 15...Piston, 16...Cylinder, 17...Spring member, 18, 19...Slider, 20...Intermediate connecting member, 21...Cylinder holder, 22...End side holder, 23...Piston side holder, 24...Connecting plate

Claims

1. A bidirectional retraction device for a sliding door, in which a piston-type damper is disposed within a case having guide sections formed on both side walls and temporary stops formed at both ends of the guide sections, a slider having engagement sections at a leading end and trailing end of the piston-type damper which engage with the guide sections or temporary stops and which is rotatably connected to an engagement pin provided on the door frame or rail, the slider being capable of engaging and disengaging with the engagement pin, and a spring member is applied to the slider in the retraction direction, and at least one of the sliders is engaged with the temporary stops of the case, A bidirectional retraction device for a sliding door, characterized in that the piston-type damper consists of two piston-type dampers connected in series via an intermediate connecting member, a cylinder holder is attached to each of the two piston-type dampers, the cylinder holder is slidably provided along the case, and the intermediate connecting member is slidably provided along the case.

2. 2. The bidirectional retraction device for a sliding door according to claim 1, wherein said spring members are provided between said slider and said intermediate connecting member.

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