Stretcher fixture and method for stretching springs

Abstract

To provide a jig and method for stretching a spring so that unintended frictional resistance does not occur between the strands of the spring during the process of winding and tightening the spring. [Solution] A stretcher jig 1 for moving a crimping plug 108 connected to a spring 106 in order to stretch the spring 106 provided on a shaft 105, comprising: a lock arm 11 that engages with the shaft 106; and an operating arm 12 that is rotatably attached to the lock arm 11 by a pivot shaft, the operating arm 12 having an action part that contacts a member (winding device 200) attached to the crimping plug 108, and an effort point part that is on the opposite side of the action part with respect to the pivot shaft.

Description

TECHNICAL FIELD

[0001] The present invention relates to a stretcher jig for stretching a spring provided on a shaft, and a method for stretching a spring.

BACKGROUND ART

[0002] In an opening / closing device represented by a shutter, in which the opening / closing body is opened and closed in the vertical direction, a means for correcting the self-weight of the opening / closing body is provided to reduce the load during the opening / closing operation. As one of such means, there is a method using the elastic force of a spring. By setting the elastic force of the spring and the self-weight of the opening / closing body to be substantially balanced, the load caused by the self-weight of the opening / closing body is prevented (or reduced) during the opening / closing operation of the opening / closing body. During construction of such an opening / closing device, an operation of tightening the spring is performed to set the elastic force of the spring in accordance with the weight of the opening / closing body, and techniques related to a winding device used for the spring tightening operation are disclosed in Patent Document 1 and Patent Document 2.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0003]

PATENT DOCUMENT 1

PATENT DOCUMENT 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] As the spring for correcting the self-weight of the opening / closing body, a spring such as a tension coil spring, which has very little gap between the element wires constituting the spring, may be used in some cases. In the process of setting the elastic force of a spring as described above, tightening the spring increases the number of turns. This has the effect of narrowing the spacing between the spring strands, and therefore, if the spring originally has small gaps between the strands, the strands may end up in a state where they are pressed against each other. When the strands are pressed against each other in this way, the frictional resistance between the strands increases, and there is a possibility that the spring may not perform as intended.

[0005] In view of the above, the present invention aims to provide a jig and method for stretching a spring that prevents unintended frictional resistance from occurring between the strands of the spring during the process of winding the spring. [Means for solving the problem]

[0006] (Composition 1) A stretcher jig for moving a crimping plug connected to a spring in order to stretch the spring provided on a shaft, comprising: a locking arm that engages with the shaft; and an operating arm that is rotatably mounted on a pivot shaft to the locking arm, the operating arm having an action portion that contacts a member attached to the crimping plug and an action point portion that is on the opposite side of the action portion with respect to the pivot shaft.

[0007] (Configuration 2) The stretcher jig according to configuration 1, wherein the lock arm has a recess for receiving the shaft, and is equipped with a size-changing member that changes the size of the recess in the direction that is the diameter of the shaft when the shaft is received.

[0008] (Composition 3) The stretcher jig according to configuration 2, wherein the size-changing member is composed of a member whose amount of protrusion into the recess changes when it rotates.

[0009] (Composition 4) The stretcher jig according to configuration 3, wherein the size-changing member is configured to rotate between a first position and a second position, and comprises a first contact surface that makes surface contact with the lock arm at the first position, and a second contact surface that makes surface contact with the lock arm at the second position.

[0010] (Composition 5) A stretcher jig according to any one of configurations 2 to 4, wherein when the lock arm moves to tilt with respect to the shaft due to a reaction force generated by the force applied to the member by the actuation part, the size-changing member is provided on the side of the lock arm on the side where the angle with respect to the shaft becomes smaller.

[0011] (Composition 6) The stretcher jig according to configuration 5, wherein a lock receiving plate that engages with the shaft is provided on the side of the lock arm on the side of the recess facing the size-changing member, where the angle with respect to the shaft becomes smaller when the lock arm moves to tilt relative to the shaft due to a reaction force generated by applying force to the member by the actuation part.

[0012] (Composition 7) A stretcher jig according to any one of configurations 1 to 6, wherein the working part is within the projection range of the lock arm when viewed from a direction along the axial direction of the shaft.

[0013] (Composition 8) A stretcher jig according to any one of configurations 1 to 7, wherein the working part is provided with a rotating member that contacts the member.

[0014] (Composition 9) The stretcher jig according to configuration 8, wherein the lock arm has a recess for receiving the shaft, and the upper end of the rotating member is configured to be lower than the bottom surface of the recess.

[0015] (Composition 10) The stretcher jig according to any one of configurations 1 to 9, comprising a biasing means that biases the operation arm in a closing direction relative to the lock arm.

[0016] (Configuration 11) The stretcher jig according to any one of configurations 1 to 10, wherein the operation arm includes: an arm base rotatably attached to the lock arm via a support shaft; a push arm attached to the arm base and having the action portion; and an operation bar attached to the arm base, having a length longer than the push arm, and having the force point portion.

[0017] (Configuration 12) A spring stretching method using the stretcher jig according to any one of configurations 1 to 11, comprising: a step of arranging the lock arm to mesh with the shaft; a step of opening the operation arm relative to the lock arm to bring the action portion into contact with the member; and a step of further pushing and opening the operation arm to stretch the spring.

[0018] (Configuration 13) The spring stretching method according to configuration 12, wherein the lock arm is meshed with the shaft such that a position where the action portion abuts the member is directly below or directly above the shaft.

[0019] (Configuration 14) The spring stretching method according to configuration 12 or 13, wherein the member is a winding device for tightening the spring. [Advantageous Effects of the Invention]

[0020] According to the present invention, it is possible to provide a jig and a method for stretching a spring that prevent unintended frictional resistance from occurring between the spring wires during the work of tightening the spring. [Brief Description of the Drawings]

[0021] [Figure 1] A diagram showing a stretcher jig according to an embodiment of the present invention. [Figure 2] Diagram showing the locking arm of the stretcher fixture of the embodiment. [Figure 3] Diagram showing the lock receiving plate and lock plate (size changing member) of the stretcher jig of the embodiment. [Figure 4] Explanatory diagram of a stretcher jig according to an embodiment. [Figure 5] Explanatory diagram of a stretcher jig according to an embodiment. [Figure 6] Diagram showing the arm base of the stretcher jig of the embodiment. [Figure 7] Diagram showing the push arm of the stretcher jig in the embodiment. [Figure 8] Diagram showing the operating bar of the stretcher jig in the embodiment. [Figure 9] A photograph showing the test use of the stretcher fixture of the embodiment. [Figure 10] A schematic perspective view showing an example of an opening and closing device (overhead door). [Figure 11] A diagram showing an example of a spring mounting section for compensating for the weight of the opening and closing mechanism. [Figure 12] A schematic diagram showing an example of spring tightening work. [Modes for carrying out the invention]

[0022] The embodiments of the present invention will be described in detail below with reference to the drawings. Note that the following embodiments are merely examples of how the present invention can be implemented, and do not limit the present invention to their scope.

[0023] First, we will describe an example of an opening / closing device that is used with the stretcher jig 1 of this embodiment. Figure 10 shows the opening / closing device 100, which is the target of the stretcher jig 1, and is a perspective view from the indoor side. Figure 11 shows the mounting part of the spring for compensating for the load due to the weight of the opening / closing body. The opening / closing device 100 is, for example, an opening / closing device that opens and closes an opening formed in a wall that separates the indoors from the outdoors, and more specifically, is an opening / closing device referred to as an overhead door or an overhead sliding door. As shown in Figure 10, the opening / closing device 100 is An opening / closing body 101 in which multiple panel bodies are connected so as to be rotatable to one another, A guide rail 102 that guides the movement of the opening / closing body 101, It includes a self-weight correction mechanism for correcting the load caused by the self-weight of the opening / closing body 101. As shown in Figures 10 and 11, the self-weight compensation mechanism is A wire rope 103 connected near the lower end of the opening / closing body 101, A drum 104 for winding up the wire rope 103, A shaft 105 connected to the drum 104, A crimping plug 108 is inserted through the shaft 105, The device includes a spring 106, one end of which is fixed to a bracket 107 that is fixed to the building structure, and the other end of which is fixed to a shaft 105 via a crimping plug 108.

[0024] Multiple rollers 1011 are provided at both ends in the width direction of the opening / closing body 101, and the guide rail 102 guides the movement of the rollers 1011. The opening / closing body 101 consists of multiple panel bodies connected to each other by hinges so as to be rotatable, and is movable along the guide rail 102 between the closed state shown in Figure 10 and the open state in which the opening / closing body 101 is in a nearly horizontal position at the top. In the self-weight compensation mechanism, the elastic force of the spring 106 and the self-weight of the opening / closing body 101 are set to be roughly balanced in order to reduce the load when the opening / closing body 101 is moved, etc. The shaft 105 is connected to a drum 104, which generates a rotational moment due to the weight of the opening / closing body 101 applied via a wire rope 103 (the drum 104 is fixed to the shaft 105), and a crimping plug 108, which generates a rotational moment due to the elastic force of a spring 106, is also connected. As a result, the rotational moment based on the elastic force of the spring 106 and the rotational moment based on the weight of the opening / closing body 101 act in opposite directions on the shaft 105 (they cancel each other out), and the load based on the weight of the opening / closing body 101 is canceled or reduced. The crimping plug 108 is a component used to set the elastic force of the spring 106 (to crimp the spring). As shown in Figure 11, the crimping plug 108 has a bolt 1082 which is a means of fixing it to the shaft 105, and a fitting recess 1081 which is used when rotating the crimping plug 108 (crimping the spring). The crimping plug 108 in this example has four fitting recesses 1081 arranged at 90-degree intervals on its outer circumference (there are fitting recesses at both ends in the diametrical direction). When the bolt 1082 is not tightened, the crimping plug 108 can rotate around the shaft 105 as its axis. When the bolt 1082 is tightened, the bolt comes into contact with the shaft and is fixed to the shaft 105. As described above, one end of the spring 106 is fixed to the bracket 107 and the other end is fixed to the crimping plug 108. By rotating the crimping plug 108, the spring 106 is twisted, imparting elastic force. In this state, the crimping plug 108 is fixed to the shaft 105, thereby imparting a rotational moment to the shaft 105.

[0025] Figure 12 is a schematic diagram showing an example of a winding tightening operation of a spring 106 mounted on a shaft 105. It is an explanatory diagram showing how the winding operation is performed using a winding device 200 and a rotary tool T (such as an electric tool or air tool) to enable efficient and safe winding tightening. The winding device 200 (or the rotating tool T) itself, which utilizes such a rotating tool, can be any type; therefore, its configuration and usage will not be explained here. When a spring is tightened through this process, the number of turns increases (the number of spring strands aligned axially increases). This creates an effect that narrows the spacing between the spring strands, and therefore, if the spring originally had small gaps between the strands, the strands may end up pressing against each other. When the strands are pressed against each other in this way, frictional resistance increases, and the spring may not perform as intended. The stretcher jig 1 of this embodiment is a jig for slightly stretching the spring 106 to reduce friction between strands in order to avoid this. More specifically, it stretches the spring 106 by moving the crimping plug 108 connected to the spring 106, and for this purpose, it is a jig that moves the winding device 200, which is a "member attached to the crimping plug," in the axial direction relative to the shaft 105. Figure 9 shows a photograph illustrating the test use of the stretcher jig 1 of this embodiment. The stretcher jig 1 has a member (lock arm 11) that engages with the shaft 105 and a member (operating arm 12) that rotates relative to it, and uses the principle of leverage to push and move the winding device 200.

[0026] Figure 1 shows a stretcher jig 1 according to an embodiment of the present invention, where Figure 1(a) is a left side view and Figure 1(b) is a top view. Hereafter, in the test use configuration shown in Figure 9, the side facing upwards will be referred to as the top (top surface), the opposite side as the bottom (bottom surface), the direction along the axis of the shaft 105 as the left-right direction (the surface viewed from this direction as the side), the front side (the side with the operating bar) as the base end, and the opposite side as the tip. Note that these are for the sake of explanation, and for example, which surface will be considered the top surface can be determined arbitrarily.

[0027] The stretcher jig 1 of this embodiment is a jig for moving a crimping plug 108 connected to the spring 106 in order to crimp the spring 106 in order to stretch the spring 106 provided on the shaft 105, A lock arm 11 that engages with the shaft 105, An operating arm 12 is rotatably attached to the lock arm 11 by a pivot shaft (hinge pin 13), and the operating arm 12 has a cam follower (working part composed of a rotating member) 14 that abuts against a member (winding device 200) attached to the winding plug 108, and a bar grip (point of force) 1234 located on the opposite side of the cam follower (working part) 14 with respect to the pivot shaft (hinge pin 13), It is equipped with.

[0028] Figure 2 shows the lock arm 11, with Figure 2(a) being a left side view and Figure 2(b) being a top view. The lock arm 11 has a U-shaped recess 111 in a side view that receives the shaft 105, and two tongue-shaped portions for attaching the support shaft (hinge pin 13) are formed above and below the recess 111 on the base end side, so as to protrude toward the base end side. The upper tongue portion 1161 has a hole 11H1 through which the hinge pin 13, which serves as the support shaft, can be inserted, and the lower tongue portion 1162 has a screw hole 11H2 into which the hinge pin 13 is engaged. By attaching the hinge pin 13 to the tongue portion, a hinge shaft (support shaft) is formed. A lock plate mounting recess 115 is formed at the base end of the U-shaped recess 111, with a notch cut into the left side. The notch in the lock plate mounting recess 115 forms a locking surface 114 that locks the lock plate 112. The screw hole 11H3 is a screw hole for engaging the mounting bolt B2 (see Figure 1(b)) that rotatably attaches the lock plate 112. A screw hole 11H4 is formed at the tip of the U-shaped recess 111 for engaging the mounting bolt B3 (see Figure 1(b)) for attaching the lock receiving plate 113.

[0029] Figure 3 shows the lock plate 112 and lock receiving plate 113 attached to the lock arm 11, where Figure 3(a) is a side view showing the lock receiving plate 113 and Figure 3(b) is a side view showing the lock plate 112.

[0030] The lock plate 112 is basically a roughly rectangular plate, but the corner between the first contact surface 1121 and the second contact surface 1122 is arc-shaped. Preferably, the lock plate 112 is made of a material with higher hardness than the stretcher jig body (lock arm 11, etc.). Hole 112H is a mounting hole through which a mounting bolt B2 is inserted to rotatably attach to the lock plate mounting recess 115 of the lock arm 11. The distance between the center of hole 112H (i.e., the axis of rotation) and the first contact surface 1121 is the same as the distance between the center of hole 112H and the second contact surface 1122, and the center of the arc between the first contact surface 1121 and the second contact surface 1122 is the center of hole 112H. Furthermore, a first meshing surface 1123 is formed on the opposite side of the first contact surface 1121, and a second meshing surface 1124 is formed on the opposite side of the second contact surface 1122. The distance between the first meshing surface 1123 and the center of the hole 112H is configured to be different from the distance between the second meshing surface 1124 and the center of the hole 112H. Figure 4 illustrates the function of the lock plate 112 attached to the lock arm 11. Figure 4(a) is a side view showing the lock plate 112 in the first position, and Figure 4(b) is a side view showing the lock plate 112 in the second position. As can be seen from Figure 4, the lock arm 11 and the lock plate 112 are configured as described above so that when the lock plate 112 is in the first position shown in Figure 4(a), the first contact surface 1121 makes surface contact with the locking surface 114 and maintains that position, and when the lock plate 112 is in the second position shown in Figure 4(b), the second contact surface 1122 makes surface contact with the locking surface 114 and maintains that position, and the lock plate 112 is also configured to rotate between the two. When the lock plate 112 is in the first position shown in Figure 4(a), the first engagement surface 1123 protrudes into the recess 111, and when it is in the second position shown in Figure 4(b), the second engagement surface 1124 protrudes into the recess 111. This changes the width of the recess 111 (the vertical dimension in Figure 4), allowing it to appropriately accommodate shafts of different diameters. As can be understood from the above, the lock plate 112 is a "size-changing member that changes the size of the recess of the lock arm in the direction that is the diameter of the shaft when the shaft is received," and is a "member whose amount of protrusion into the recess of the lock arm changes when it rotates." Furthermore, it is "configured to rotate between a first position and a second position, and comprises a first contact surface that makes surface contact with the lock arm in the first position, and a second contact surface that makes surface contact with the lock arm in the second position." Furthermore, since the lock plate 112 is a component that can be attached to and detached from the lock arm 11, a wider variety of shaft diameters can be accommodated by preparing other lock plates with different protrusion lengths inward from the recess 111. In addition, because the lock plate 112 is a component that can be attached to and detached from the lock arm 11, the lock plate that has worn out due to use can be easily replaced.

[0031] The lock receiving plate 113 is also a roughly rectangular plate (see Figure 3(a)), and has two holes 113H through which mounting bolts B3 (2 pieces) for attaching it to the lock arm 11 are inserted. It is preferable that the lock receiving plate 113 is made of a material with higher hardness than the stretcher jig body (lock arm 11, etc.). The surface that becomes the base end when attached to the lock arm 11 has a recessed portion 1131 formed on it, and a similar recessed portion 1131 is formed on the opposite surface. As shown in Figure 4, the surface that becomes the base end when attached to the lock arm 11 is configured to protrude inward into the recess 111. The locking plate 113, together with the locking plate 112, protrudes inward from the recess 111 and engages with the shaft 105. The uneven surface 1131 functions as an anti-slip surface when it engages with the shaft 105. The lock receiving plate 113 has a symmetrical shape, allowing it to be installed even if the front and back are reversed during installation. Furthermore, if one of the protrusions 1131 wears down during use, the other protrusion 1131 can be used by reversing it and attaching it to the lock arm 11. In addition, the lock receiving plate 113 is detachable from the lock arm 11, allowing for easy replacement of a worn or damaged lock receiving plate 113.

[0032] Figure 5 is a diagram illustrating the engagement with the shaft 105. Figure 5(a) is a top view showing the state in which the shaft 105 is positioned in the recess 111, with the longitudinal direction of the lock arm 11 and the shaft 105 being perpendicular (there is some play and they are not engaged). Figure 5(b) is a top view showing the state in which the lock arm 11 engages with the shaft 105 due to the reaction force received when the operating arm 12 is opened and the working part comes into contact with the member 300 (the member attached to the crimping plug). As shown in Figure 5(b), the lock plate 112 on the base end side of the shaft 105 is provided on the left side 117 of the lock arm 11 (where the angle between it and the shaft 105 is smaller than that between it and the right side 118), and the lock receiving plate 113 on the tip end side of the shaft 105 is provided on the right side 118 of the lock arm 11 (where the angle between it and the shaft 105 is smaller than that between it and the left side 117). As can be seen from Figure 5, this arrangement allows the lock plate 112 and the lock receiving plate 113 to engage more appropriately with the shaft 105 when force is applied by opening the operating arm 12. The lock plate 112 is "provided on the side of the lock arm on which the angle with respect to the shaft becomes smaller when the lock arm moves in such a way that it tilts relative to the shaft due to the reaction force generated when a force is applied to the member (the member attached to the crimping plug) by the working part." Furthermore, the lock receiving plate 113 is "provided on the side of the lock arm that faces the size-changing member (lock plate 112) in the recess of the lock arm, and when the lock arm moves to tilt relative to the shaft due to the reaction force generated by applying force to the member (the member attached to the crimping plug) by the working part, the side of the lock arm on which the angle with respect to the shaft becomes smaller." It should be noted that the terms "lock plate" and "lock receiver plate" are merely for convenience; both are essentially the same concept in that they are "members that protrude inward from a recess and engage with the shaft."

[0033] The operating arm 12, which is pivoted to the lock arm 11, is as shown in Figure 1(b), An arm base 122 is rotatably attached to the lock arm 11 by a pivot shaft (hinge pin 13), A push arm 121 is attached to the arm base 122 and has a cam follower (acting part) 14, It includes an operating bar 123 that is attached to the arm base 122, has a longer length than the push arm 121, and has a bar grip (point of force application) 1234, In this embodiment, the operating arm 12 is shown as an example in which three components, a push arm 121, an arm base 122, and an operating bar 123, are joined together. However, the present invention is not limited to this, and may be formed by combining four or more parts, or conversely, by combining two parts or by being composed of one part.

[0034] Figure 6 shows the arm base 122, with Figure 6(a) being a left side view, Figure 6(b) being a view from the base end, and Figure 6(c) being a bottom view. The arm base 122 is a roughly U-shaped member when viewed from the base end (or tip end), and has two tongue-shaped portions 1222 formed on the top and bottom of one side of the columnar portion 1221, protruding from the support shaft (hinge pin 13). The upper and lower tongue portions 1222 each have holes 122H1 through which a hinge pin 13, which serves as a support shaft, can be inserted. The hinge shaft (support shaft), which is formed by attaching the hinge pin 13 to the lock arm 11, is rotatably inserted through these holes, thereby rotatably attaching the arm base 122 to the lock arm 11. Although this configuration is used as an example in this embodiment, the present invention is not limited to this, and any mechanism that can rotatably support the operating arm 12 with respect to the lock arm 11 may be used. In this embodiment, a torsion spring 15 is provided on the hinge shaft, which is a biasing means that biases the operating arm 12 in the closing direction relative to the lock arm 11 (see Figure 1). The torsion spring 15 (biasing means) is not an essential component in the present invention, and it may be omitted (however, it is preferable to have this biasing means as it can reduce the rattling and other issues that may occur in the parts). The columnar portion 1221 has a screw hole 122H2 that extends from the base to the tip for engaging the operating bar 123. Furthermore, a screw hole 122H3 is formed on the bottom surface of the columnar portion 1221 for engaging a bolt B1 (see Figure 1(a)) for attaching the push arm 121. A screw hole 122H4 is formed on the base end surface of the columnar portion 1221 for screwing in a cord attachment fitting 16 (see Figure 1). The cord attachment fitting 16 is for preventing falls during work at height, and is used to attach a fall prevention cord connected to a waist belt or the like.

[0035] Figure 7 shows the push arm 121, with Figure 7(a) being a left side view and Figure 7(b) being a top view. Figure 7(c) is a top view showing the cam follower (acting part) 14 provided on the push arm 121, and Figure 7(d) is a side view. The push arm 121 is basically a plate-shaped (or rod-shaped) member, with a mounting hole 12H1 for attaching the cam follower 14 at its tip and a hole 121H2 for inserting a bolt B1 for attaching it to the arm base 122 at its base. The upper surface of the base end of the push arm 121 is partially cut out, forming a joint 1211 with the arm base 122. The stepped portion 1212 formed by the cutout engages with the front edge of the bottom surface of the columnar portion 1221 of the arm base 122, and is fixed in place with bolt B1 so that they do not rotate relative to each other. The elongated hole 121H3 formed in the push arm 121 is a weight-reducing cutout. The cam follower (rotating member that acts as the working part) 14 is inserted through the mounting hole 121H1 at the tip of the push arm 121 and attached by a nut N1 (see Figure 1(a)). Note that the cam follower (rotating member) is not essential in this invention, and it is also acceptable to have no rotating member (the working part is not a rotating member). However, it is preferable for the working part to be a rotating member because having a rotating member at the working part, which is the part that contacts the "member attached to the crimping plug," makes the operation smoother during use and reduces the risk of damaging the "member attached to the crimping plug."

[0036] Figure 8 shows the operating bar 123, with Figure 8(a) being a view from the tip side and Figure 8(b) being a top view. The operating bar 123 is a rod-shaped member, with a threaded portion 1231 formed at its tip that engages with the threaded hole 122H2 of the arm base 122, and a threaded portion 1232 formed at its base that engages with the bar grip (point of force) 1234 (see Figure 1). In this embodiment, a bar grip 1234 (which serves as a gripping part held by a person) is attached separately to the base end of the operating bar 123 as an example. However, the operating bar 123 itself may also constitute the gripping part (the point where a person holds it and applies force). The flat surface 1233 (there is a similar flat surface 1233 on the back side as well (see Figure 1(a))) is an engagement part for gripping a tool (wrench) used when engaging the operating bar 123 with the screw hole 122H2 of the arm base 122.

[0037] In the stretcher jig 1 of this embodiment, the lock arm 11 has a U-shaped recess 111 (opening at the top) in a side view that receives the shaft 105, and the upper end of the cam follower (rotating member) 14, which is the working part, is configured to be lower than the bottom surface of the recess 111. This prevents the working part from interfering with the shaft 105 received in the recess 111. Furthermore, the cam follower (rotating member) 14, which is the working part, is positioned close to the recess 111 (so that the working part is within the projection range of the lock arm when viewed from a direction along the axis of the shaft). This configuration allows the working part to contact the "member attached to the crimping plug" at a position closer to the shaft 105. If the working part contacts (applies force to) the "member attached to the crimping plug" at a position far from the shaft 105, a large rotational moment is generated in the "member attached to the crimping plug," making it difficult for the "member attached to the crimping plug" to move smoothly along the axis of the shaft 105. However, with the above configuration, this problem is reduced.

[0038] The method of using the stretcher jig 1 of this embodiment, which has the above configuration (method of stretching the spring), will be outlined below. As explained in Figure 12, when it becomes necessary to stretch the spring 106 due to the tightening of the spring 106, first rotate the lock plate 112 to match the diameter of the shaft 105. As mentioned above, it may also be possible to match the diameter of the shaft 105 by replacing the lock plate with a replacement lock plate. Next, as shown in Figure 9(a), the recess 111 of the lock arm 11 is positioned relative to the shaft 105 at a location adjacent to the winding device 200, which is a "member attached to the winding plug" (positioned so that the lock arm engages with the shaft). In this state, when the operating arm 12 is operated so that the push arm 121 opens relative to the lock arm 11, the cam follower 14, which is the working part, comes into contact with the winding device 200. At this time, it is preferable to "engage the lock arm with the shaft so that the position where the working part comes into contact with the winding device (the member attached to the winding plug) is directly below or directly above the shaft." As shown in Figure 5(b), by making the working part (cam follower) come into contact with the "member attached to the winding plug" 300 at a position directly below the shaft 105, the "member attached to the winding plug" can be moved more smoothly as described above. By applying force to further push open the operating arm 12, the winding device 200 moves along the axial direction of the shaft 105, as shown in Figure 9(b). This causes the winding tightening plug 108 attached to the winding device 200 to also move, and consequently, the spring 106 is stretched. Note that during the winding tightening operation of the spring 106, which is a prerequisite for this operation, the bolt 1082 of the winding tightening plug 108 is loosened, allowing the winding tightening plug 108 to rotate relative to the shaft 105 (its fixing is released), and therefore it is also in a state where it can move along its axial direction relative to the shaft 105. As can be understood from the above explanation, the spring 106 can be easily stretched (adjusted for frictional force between strands), and it can also be held in the stretched state with one hand. By holding the extended state with one hand and tightening the bolt 1082 (see Figure 11) of the crimping plug 108 with the other hand, the crimping plug 108 is fixed to the shaft 105, and the spring 106 is maintained in an appropriately extended state. Furthermore, to make it easier to maintain the extended state, a ratchet mechanism may be provided in the rotation mechanism of the lock arm 11 and the operating arm 12.

[0039] As described above, the stretcher jig 1 of this embodiment allows for easy adjustment of the length of the spring 106 to prevent unintended frictional resistance from occurring between the spring wires.

[0040] In this embodiment, the size-changing member for adjusting the width of the recess that receives the shaft according to the shaft's thickness is provided as an example, and is made of a lock plate. However, the present invention is not limited to this, and the size-changing member may also be made of a lock receiving plate. As can be understood from the above description, the lock receiving plate can also be made rotatable (or interchangeable with a lock receiving plate of a different size) to serve as a size-changing member. The size-changing member may also be made of both the lock plate and the lock receiving plate. Note that the lock plate and lock receiving plate are not essential in this invention, and it is acceptable to omit either or both of them (it is possible to make the recess itself engage with the shaft). However, as described above, it is preferable to have both a lock plate and a lock receiving plate.

[0041] In this embodiment, the "member attached to the crimping plug," which is the component on which the stretcher jig acts, is given as an example of a winding device, but the present invention is not limited to this. As can be understood from the above description, the "member attached to the crimping plug" may be any member that, by being attached to the crimping plug, can be moved by the stretcher jig, thereby moving the crimping plug (and consequently stretching the spring).

[0042] In this embodiment, an overhead door was described as an example of an object to which the spring tightening is performed. However, the present invention is not limited to this, and can be applied to any opening and closing device in which an opening and closing body moves vertically, such as a shutter, which uses a spring as a self-weight compensation mechanism to compensate for the load due to the weight of the opening and closing body, and is equipped with a tightening plug for tightening the spring. [Explanation of symbols]

[0043] 1...Stretcher jig 11... Lock Arm 111...recess 112... Lock plate (size change component) 1121...First contact surface 1122...Second contact surface 113... Lock receiving plate 114... Locking surface 12...Operating arm 121... Push Arm 122...Arm base 123... Operation bar 1234...Bar grip (point of force application) 13...Hinge pin (support shaft) 14... Cam follower (rotating member, working part) 15... Torsion spring (biasing mechanism) 100...Opening and closing device 105...shaft 106... Spring 108...Crimp plug 200... Winding device (a component attached to the winding plug)

Claims

1. A jig for moving a crimping plug connected to a spring in order to stretch the spring provided on the shaft, A locking arm that engages with the aforementioned shaft, An operating arm rotatably mounted to the lock arm by a pivot shaft, the operating arm having an action portion that contacts a member attached to the crimping plug, and an action portion that is on the opposite side of the action portion with respect to the pivot shaft, A stretcher jig equipped with the following features.

2. The stretcher jig according to claim 1, wherein the lock arm has a recess for receiving the shaft, and is equipped with a size-changing member that changes the size of the recess in the direction that is the diameter of the shaft when the shaft is received.

3. The stretcher jig according to claim 2, wherein the size-changing member is composed of a member whose amount of protrusion into the recess changes when rotated.

4. The stretcher jig according to claim 3, wherein the size-changing member is configured to rotate between a first position and a second position, and comprises a first contact surface that makes surface contact with the lock arm at the first position, and a second contact surface that makes surface contact with the lock arm at the second position.

5. The stretcher jig according to any one of claims 2 to 4, wherein when the lock arm moves to tilt with respect to the shaft due to a reaction force generated by the force applied to the member by the actuation part, the size changing member is provided on the side of the lock arm on the side where the angle with respect to the shaft becomes smaller.

6. The stretcher jig according to claim 5, wherein a lock receiving plate that engages with the shaft is provided on the side of the lock arm on the side of the recess facing the size-changing member, on the side where the angle with respect to the shaft becomes smaller when the lock arm moves to tilt with respect to the shaft due to a reaction force generated by applying force to the member by the working part.

7. The stretcher jig according to any one of claims 1 to 4, wherein the working part is within the projection range of the lock arm when viewed from a direction along the axial direction of the shaft.

8. The stretcher jig according to any one of claims 1 to 4, wherein the working part is provided with a rotating member that contacts the member.

9. The stretcher jig according to claim 8, wherein the lock arm has a recess for receiving the shaft, and the upper end of the rotating member is configured to be lower than the bottom surface of the recess.

10. A stretcher jig according to any one of claims 1 to 4, further comprising a biasing means for biasing the operating arm in the closing direction relative to the lock arm.

11. The aforementioned operating arm An arm base is rotatably attached to the lock arm by the pivot shaft, A push arm having the action part and attached to the arm base, A stretcher jig according to any one of claims 1 to 4, comprising: an operating bar attached to the arm base, having a length longer than the push arm, and having the point of force application.

12. A method for stretching a spring using a stretcher jig according to any one of claims 1 to 4, The steps include: positioning the lock arm so that it engages with the shaft; The steps include opening the operating arm relative to the locking arm so that the working part comes into contact with the member, The steps include: extending the spring by further pushing open the operating arm; A method for stretching a spring, which includes the following features.

13. The method for stretching a spring according to claim 12, wherein the lock arm is engaged with the shaft such that the position where the working portion contacts the member is directly below or directly above the shaft.

14. The method for stretching a spring according to claim 12 or 13, wherein the member is a winding device for tightening the spring.

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