Folding mechanism of rod-like member

Abstract

To provide a folding mechanism of a rod-like member, capable of suppressing abrasion and deformation in long term use.SOLUTION: A folding mechanism 35 of a rod-like member comprises connection members 36, 37, and a first shaft 38 rotatably connecting the pair of connection members 36, 37. The one connection member 36 is configured including: a connection member body 55; a lever member 65 disposed rotatably to the connection member body 55 and having a tip part 66 capable of coming into contact with a contacted surface 44 disposed on the other connection member 37; and a spring member 74 energizing the lever member 65. The rotation in the folding direction of a rod-like member 24b is regulated by contact between a rotation regulation surface 68 disposed at the tip part 66 of the lever member 65 and the contacted surface 44, and the tip part 66 of the ever member 65 is separated from the contacted surface 44 by rotating the lever member 65 against the energization force of the spring member 74, so that the rotation in the folding direction of the rod-like member 24b is permitted.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a folding mechanism for a rod-shaped member. [Background technology]

[0002] In wheelchairs, in order to make the wheelchair smaller when not in use or when loading it into a car, a structure is adopted in which a folding bracket is inserted in the middle of the rod-shaped member (frame member) that supports the push handle, making it possible to fold the upper rod-shaped member including the push handle.

[0003] Conventional back folding fittings, as disclosed in Patent Document 1 below, for example, connect a pair of upper and lower pivot members via a pivot, and a locked state in which folding action is restricted is achieved by inserting a lock pin on one of the pivot members into a lock hole on the other pivot member, and an unlocked state in which folding action is permitted is achieved by removing the lock pin from the lock hole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-000320 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of a structure using a lock hole and a lock pin, there is a problem in that the peripheral wall of the lock hole and the lock pin are prone to localized wear and deformation due to rubbing between the peripheral wall of the lock hole and the lock pin over long periods of use.

[0006] The present invention has been made against the background described above, and has as its object to provide a folding mechanism for a rod-shaped member that is capable of suppressing wear and deformation when used for a long period of time. [Means for solving the problem]

[0007] The folding mechanism of the rod-shaped member according to the first aspect of the present invention is defined as follows. a pair of connecting members attached to respective opposing ends of the pair of rod-shaped members; a first shaft that rotatably connects the pair of connecting members, One of the connecting members is A connecting member body, a lever member rotatably provided on the connecting member body and having a tip portion capable of contacting an abutment surface provided on the other connecting member; a spring member that biases the lever member so as to protrude a tip portion of the lever member toward the abutment surface, By contact between the rotation control surface provided at the tip of the lever member and the abutment surface, rotation of the rod-shaped member in the folding direction is restricted, and by rotating the lever member against the biasing force of the spring member, the tip of the lever member moves away from the abutment surface, allowing rotation of the rod-shaped member in the folding direction.

[0008] According to the folding mechanism for the rod-shaped members of the first aspect thus defined, when in use (in a non-folded state), the load acting on the pair of rod-shaped members connected so as not to rotate is received by the abutment of two opposing flat surfaces (the rotation restricting surface of the lever member and the abutted surface of the other connecting member). Therefore, compared to a folding mechanism using a conventional lock hole and lock pin, the contact area at the abutment part increases and the pressure per unit area decreases, so that wear and deformation during long-term use can be suppressed.

[0009] Here, a gap adjustment means for adjusting the amount of gap between the one connecting member and the other connecting member can be provided at a position opposite to the position where the lever member abuts, across the normal line of the abutted surface passing through the axis of the first shaft (second aspect). In this way, rattling of the rod-shaped member during use can be adjusted.

[0010] The third aspect of the present invention is defined as follows: In the folding mechanism of the rod-shaped member of the first aspect, when the rotation of the rod-shaped member is restricted, the tip of the lever member is accommodated in an internal space surrounded by the other connecting member and the other rod-shaped member to which the other connecting member is attached, and the lever member extends to the outside through an opening formed between the one connecting member and the other rod-shaped member, and an operating portion of the lever member is disposed outside the connecting member body, During the process of rotating the rod-shaped member in the folding direction, the operating portion of the lever member is moved closer to the first axis based on the biasing force of the spring member, so that the height from the first axis to the top of the operating portion becomes lower than the height from the first axis to the edge of the opening.

[0011] According to the folding mechanism of the rod-shaped member of the third aspect thus defined, interference between the operating portion and the other rod-shaped member can be avoided, and one rod-shaped member and one connecting member can be folded at a large rotation angle.

[0012] In the present invention, a part of the abutted surface of the other connecting member can be configured as a separate, detachable second abutted member (fourth aspect). In this way, if the second contact member becomes worn after a long period of use, only the second contact member can be replaced as needed. Also, if the second contact member is made of a low-friction material with a smaller friction coefficient than the other connecting member, the force required for the folding operation can be reduced.

[0013] In addition, in this invention, the rod-shaped member can be a rear rod-shaped member that supports a push handle of a wheelchair (a fifth aspect). The folding mechanism of this invention is particularly suitable for use in folding rear rod-shaped members including push handles of a wheelchair. [Brief description of the drawings]

[0014] [Figure 1]1 is a side view of a wheelchair equipped with a folding mechanism according to one embodiment of the present invention; [Diagram 2] FIG. 2 is an external perspective view of the folding mechanism of FIG. [Diagram 3] 3A and 3B are views showing an upper connecting member and a lower connecting member which constitute the folding mechanism in FIG. 2, in which (A) is an external perspective view and (B) is a cross-sectional view thereof. [Figure 4] FIG. 13 is a view showing the lower connecting member alone. [Diagram 5] 13 is a diagram showing the folding mechanism in a locked state in which rotation in the folding direction is restricted. FIG. [Figure 6] 11A to 11C are explanatory diagrams of a folding operation in the embodiment. [Figure 7] FIG. 7 is an explanatory diagram of the folding operation following FIG. 6. [Figure 8] 6A to 6C are explanatory views of the operation of a screw member serving as a gap adjusting means. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of a wheelchair equipped with a folding mechanism according to an embodiment of the present invention. The wheelchair 10 includes left and right frames 12, a flexible cloth seat 14 disposed between the frames 12, and left and right front wheels 16 and rear wheels 17 attached to the frames 12. In this specification, left and right refer to the left and right of a wheelchair user seated in the wheelchair 10, and front and rear refer to the front and rear of a wheelchair user seated in the wheelchair 10. FIG. 1 shows only the left side of the wheelchair 10, but the right side of the wheelchair 10, not shown, also includes a frame 12, a front wheel 16, and a rear wheel 17 that are symmetrical to the left side of FIG. 1.

[0016] Each frame 12 includes an upper rod-shaped member 19 extending in the front-rear direction and having an arm support (armrest portion) 18 attached to its upper surface, an intermediate rod-shaped member 20 disposed below the upper rod-shaped member 19 and extending in the front-rear direction, a front rod-shaped member 21 connected to the front end of the intermediate rod-shaped member 20 and extending in the vertical direction, a lower rod-shaped member 23 disposed below the intermediate rod-shaped member 20, extending in the front-rear direction and having its front portion connected to the front rod-shaped member 21, and a rear rod-shaped member 24 extending in the vertical direction and connecting the rear portion of the lower rod-shaped member 23 to the rear end of the intermediate rod-shaped member 20 and the rear end of the upper rod-shaped member 19 and erected behind the seat 14. These rod-shaped members constituting part of the frame 12 are made of metal pipes.

[0017] The left and right rear rod-like members 24, 24 are fitted with corresponding ends of a flexible cloth back support 29. The rear rod-like members 24 and the back support 29 form a backrest against which a wheelchair user leans.

[0018] In the figure, reference numeral 27 denotes a push handle made of resin that is grasped by the caregiver when moving the wheelchair 10. The push handle 27 is supported by the rear rod-shaped members 24 that extend upward.

[0019] An axle support hole (not shown) is provided in the lower part of each rear rod-shaped member 24, and the axle of the rear wheel 17 is fitted into the axle support hole to support the rear wheel 17 for free rotation. The rear wheel 17 in this example includes a rubber or resin tire 28 mounted on the outer periphery of a hard rim 17b.

[0020] An inverted L-shaped foot support rod 25 is connected to each front rod-shaped member 21, and a foot support (footrest portion) 26 is attached to the lower end of each foot support rod 25.

[0021] A crossbar 31 having an X-shape in a front view is disposed between the left and right frames 12, 12, and the left and right frames 12, 12 are connected to each other via each crossbar 31 in a foldable manner.

[0022] 1, the folding mechanism 35 of this embodiment is provided between the lower rod 24a and the upper rod 24b constituting the rear rod member 24 as the back side rod member, and the upper rod portion including the push handle 27 can be folded backward. The folding mechanism 35 will be described in detail below.

[0023] The folding mechanism 35 includes a pair of connecting members, which are an upper connecting member 36 and a lower connecting member 37, and a first shaft 38 that rotatably connects the pair of connecting members. FIG. 2 is an external perspective view of folding mechanism 35, and FIG. 3 is a view showing folding mechanism 35 separated into upper connecting member 36 side and lower connecting member 37 side. 3, the upper connecting member 36 is attached to the lower end of the upper rod 24b, and the lower connecting member 37 is attached to the upper end of the lower rod 24a. That is, a pair of connecting members 37, 36 are attached to the opposing ends of the pair of rod-shaped members 24a, 24b.

[0024] First, the lower connecting member 37 will be described. As shown in Fig. 4, the lower connecting member 37 is a metal member that is substantially U-shaped in plan view and has a pair of plate-like side wall portions 40, 40 that face each other with a gap therebetween, and a connecting portion 42 that connects these side wall portions 40 together. As shown in Fig. 4(B), the lower portion of the lower connecting member 37 serves as an attachment portion to the lower rod 24a, and the lower connecting member 37 is joined to the lower rod 24a with a notch portion 43 formed in the inner wall portion fitted onto the upper end portion of the lower rod 24a. Meanwhile, at the upper part of the lower connecting member 37, a pair of side walls 40, 40 extend in a direction away from the connecting part 42 and toward the rear side of the wheelchair beyond the outer circumferential surface of the lower rod 24a, and a connecting hole 41 into which a cylindrical first shaft 38 is inserted is formed in the pair of side walls 40, 40. The axial direction of the first shaft 38 inserted into the connecting hole 41 is the left-right direction of the wheelchair.

[0025] An abutted surface 44 against which the opposing upper connecting member 36 abuts is formed on the inner surface of the connecting portion 42. More specifically, the abutted surface 44 extends vertically from the vicinity of the upper opening 37a (see FIG. 4(B)) of the lower connecting member 37 to the vicinity of the upper end of the lower rod 24a. A recess 45 capable of accommodating a separate second abutted member 50 is formed in a part of the abutted surface 44 of the lower connecting member 37. The recess 45 has an elliptical shape in a plan view as shown in FIG. 4(C), and a stepped through-hole 46 is formed in the bottom surface of the recess 45, penetrating the connecting portion 42 in the thickness direction (see FIG. 4(B)).

[0026] The second abutted member 50 is a member having a head 51 made of a flat plate having an oval shape in a plan view and two legs 52, and is fitted into the recessed portion 45 of the lower connecting member 37 with the outward protrusions formed on the legs 52 hooked onto the stepped portions of the through-holes 46. At this time, the dimensions of each portion are adjusted so that the upper surface 50a of the second abutted member 50 is approximately flush with the abutted surface 44 formed on the lower connecting member 37, as shown in Fig. 3(B), and a flat surface that is long in the vertical direction and forms the abutted surface 44 is formed on the inner surface of the lower connecting member 37 including the second abutted member 50.

[0027] As described later, in this example, since the lever member 65 of the upper connecting member 36 slides on the upper surface 50a of the second abutted member 50, it is desirable to use a resin material with a low friction coefficient such as POM (polyacetal) or Teflon (registered trademark) for the second abutted member 50.

[0028] Next, a description will be given of the upper connecting member 36. As shown in Fig. 3, the upper connecting member 36 includes a connecting member main body 55, a lever member 65, and a spring member 74, and is attached to the end of the upper rod 24b. The connecting member body 55 has an axial mounting portion 56, and is attached to the upper rod 24b via a mounting bolt 57 with the mounting portion 56 inserted inside the upper rod 24b. The portion of the connecting member body 55 exposed below the upper rod 24b extends in a direction away from the abutted surface 44 of the opposing lower connecting member 37 and outward (toward the rear of the wheelchair) beyond the outer circumferential surface of the upper rod 24b, forming a connecting hole 58 into which the first shaft 38 is inserted. A pair of plate-like side walls 60, 60 facing each other with a gap therebetween are formed at the bottom of the connecting member body 55. A connecting hole 61 into which a second shaft 62 is inserted is formed in the pair of side walls 60, 60, and a lever member 65 is provided rotatably via the second shaft 62.

[0029] 5, the lever member 65 has a tip portion 66 that can come into contact with the abutment surface 44. The tip portion 66 is provided with a rotation restriction surface 68 that restricts the rotation of the upper rod 24b in the folding direction by abutting against the abutment surface 44. The tip portion 66 is housed in an internal space 47 surrounded by the lower connecting member 37 and the lower rod 24a (see FIG. 5). The other portion of the lever member 65 extends outward through an opening 48 formed between the connecting member main body 55 and the lower rod 24a, and has a curved shape that fits along the outer surface of the connecting member main body 55. An operating portion 70 is provided at the end opposite to the tip portion 66.

[0030] 3(B), a spring member 74 is disposed between a protrusion 67 provided near a tip end 66 of the lever member 65 and a recess 73 formed in the connecting member body 55. The lever member 65 is biased by the spring member 74 in the counterclockwise direction around the second shaft 62 so that the tip end 66 of the lever member 65 protrudes toward the abutment surface 44 provided on the lower connecting member 37.

[0031] FIG. 5 is a diagram showing the folding mechanism 35 in a locked state in which the rotation of the rod-shaped member (in this example, the upper rod 24b) in the folding direction is restricted. As shown in the figure, the distance L2 from the axis of the first shaft 38 to the rotation restriction surface 68 of the lever member 65 is greater than the distance L1 from the axis of the first shaft 38 to the abutted surface 44. The rotation restriction surface 68 of the lever member 65 abuts against the abutted surface 44 at a position lower than the normal line P of the abutted surface 44 passing through the axis of the first shaft 38, forming a first rotation restriction portion, and the rotation of the upper rod 24b in the folding direction indicated by the two-dot chain arrow in the figure is restricted. In this locked state, the push handle 27 is disposed at a predetermined position shown in FIG. 1 and is used by the caregiver. At that time, the load acting on the rear rod-shaped member 24 via the push handle 27 is received by the abutment of two opposing planes (the rotation restriction surface 68 of the lever member 65 and the abutted surface 44 of the lower connecting member 37).

[0032] On the other hand, in the locked state shown in Figure 5, when the operating portion 70 of the lever member 65 is pressed downward, the lever member 65 rotates clockwise around the second axis 62 in the figure against the biasing force of the spring member 74, the tip portion 66 of the lever member 65 moves away from the abutment surface 44, and rotation in the folding direction at the upper lever 24b is permitted.

[0033] In Figure 5, a second rotation control portion is provided on the opposite side of the normal line P from the abutment portion (first rotation control portion) by the lever member 65, which controls rotation in the direction opposite to the folding direction of the upper rod 24b by abutment between the upper connecting member 36 and the abutted surface 44.

[0034] This second rotation restricting portion is provided with a screw member 77 as a gap adjusting means for adjusting the amount of gap between the upper connecting member 36 and the lower connecting member 37. A male screw portion formed on the shaft of the screw member 77 screws into a female screw hole 76 formed on the connecting member main body 55 side, and the screw member 77 is capable of advancing and retreating in the direction toward and away from the lower connecting member 37 (more specifically, the abutted surface 44). For example, if the play in the upper rod 24b in the locked state becomes large due to wear from long-term use, the play in the upper rod 24b can be reduced by moving the head 78 of the screw member 77 closer to the abutting surface 44 of the lower connecting member 37, as shown in Figure 8.

[0035] Next, the folding operation of the upper rod 24b including the push handle 27 of the wheelchair 10 will be described. Fig. 6(A) shows a locked state in which rotation of the upper rod 24b in the folding direction is restricted. When the operating portion 70 of the lever member 65 is pressed down from this state as shown in Fig. 6(B), the lever member 65 rotates clockwise around the second shaft 62 against the biasing force of the spring member 74, and the tip portion 66 of the lever member 65 moves away from the abutment surface 44, allowing rotation of the upper rod 24b in the folding direction (clockwise in the figure).

[0036] When the upper rod 24b begins to rotate in the folding direction, as shown in Figure 6 (C), the curved surface 69 of the tip 66 of the lever member 65, which continues from the rotation control surface 68, abuts against the upper surface 50a of the second abutted member 50 due to the biasing force of the spring member 74, and the curved surface 69 of the lever member 65 slides over the upper surface 50a as the upper rod 24b subsequently rotates. When the upper rod 24b rotates further, as shown in Fig. 7(D), the abutted surface 44 (specifically, the upper surface 50a of the second abutted member 50) is disengaged from the tip 66 of the lever member 65, and the operating portion 70 of the lever member 65 approaches the first shaft 38 based on the biasing force of the spring member 74. As a result, as shown in Fig. 7(E), the height H2 from the first shaft 38 to the top of the operating portion 70 becomes lower than the height H1 from the first shaft 38 to the edge of the opening 48. Therefore, in this embodiment, the upper rod 24b and the upper connecting member 36 can be folded at a rotation angle of approximately 180° while avoiding interference between the operating portion 70 of the lever member 65 and the lower rod 24a.

[0037] On the other hand, the operation of returning the folded upper rod 24b to the position of the use state is performed in the reverse order to the operation of folding the upper rod 24b. When the upper rod 24b is rotated counterclockwise in the figure, which is the opposite to the folding direction, from the folded state of the upper rod 24b shown in Fig. 7(E), the tip 66 of the lever member 65 slides on the abutment surface 44 (more specifically, on the upper surface 50a of the second abutment member 50), and then, at the position shown in Fig. 6(A), the lever member 65 rotates counterclockwise around the second shaft 62 based on the biasing force of the spring member 74, and the rotation restriction surface 68 of the lever member 65 abuts against the abutment surface 44, and the upper rod 24b is locked in a predetermined position of use. In addition, when returning the folded upper lever 24b to the position for use, the operator only needs to rotate the upper lever 24b, and does not need to directly operate the operating portion 70 of the lever member 65.

[0038] According to the folding mechanism 35 of this embodiment as described above, when in use (unfolded state), the load acting on the upper rod 24b side of a pair of rod-shaped members that are non-rotatably connected (such as the load applied to the push handle 27) is received by the abutment of two opposing surfaces (the rotation restriction surface 68 of the lever member 65 and the abutted surface 44 of the lower connecting member 37). Therefore, compared to folding mechanisms that use conventional lock holes and lock pins, the contact area at the abutment parts is increased, and wear and deformation during long-term use can be suppressed.

[0039] Furthermore, in the folding mechanism 35 of this embodiment, a screw member 77 is provided as a gap adjustment means for adjusting the amount of gap between the upper connecting member 36 and the lower connecting member 37 on the opposite side of the abutment by the lever member 65, across the normal line P of the abutted surface 44 that passes through the axis of the first shaft 38, so that the wobble of the upper lever 24b during use can be adjusted.

[0040] Furthermore, in the folding mechanism 35 of this embodiment, in the process of rotating the upper rod 24b in the folding direction from a locked state in which the rotation of the upper rod 24b is restricted, the operating portion 70 of the lever member 65 is moved closer to the first axis 38 based on the biasing force of the spring member 74, and the height H2 from the first axis 38 to the top of the operating portion 70 is configured to be lower than the height H1 from the first axis 38 to the edge of the opening 48. Therefore, interference between the operating portion 70 and the lower rod 24a can be avoided, and the upper rod 24b and the upper connecting member 36 can be folded at a large rotation angle.

[0041] In the folding mechanism 35 of the present embodiment, a part of the abutted surface 44 of the lower connecting member 37 is configured as a separate, detachable second abutted member 50. Therefore, when the second abutted member 50 becomes worn after a long period of use, only the second abutted member 50 can be replaced as needed.

[0042] Although the embodiments of the present invention have been described in detail above, these are merely examples, and the present invention can be embodied in various modified forms without departing from the spirit of the present invention. For example, the above embodiment is an example in which, of a pair of connecting members, the connecting member with the lever member is arranged on the upper side and the connecting member with the abutment surface is arranged on the lower side, but in some cases it is also possible to arrange the connecting member with the lever member on the lower side and the connecting member with the abutment surface on the upper side. In addition, the above embodiment is an example in which a folding mechanism is provided on the back rod-shaped member (frame member) that constitutes the backrest of a wheelchair, but the present invention can also be applied to folding mechanisms of rod-shaped members used in things other than wheelchairs. [Explanation of symbols]

[0043] 10. Wheelchair 24 Posterior rod (dorsal rod) 27 Push Handle 35 Folding mechanism 36 Upper connecting member (one connecting member) 37 Lower connecting member (other connecting member) 38 First axis 44 Abutted surface 47 Interior Space 48 Aperture 50 Second abutted member 65 Lever member 66 Tip 68 Rotation restriction surface 74 Spring parts 77 Screw member (gap adjustment means) P normal

Claims

1. a pair of connecting members attached to respective opposing ends of the pair of rod-shaped members; a first shaft that rotatably connects the pair of connecting members, One of the connecting members is A connecting member body, a lever member rotatably provided on the connecting member body and having a tip portion capable of contacting an abutment surface provided on the other connecting member; a spring member that biases the lever member so as to protrude a tip portion of the lever member toward the abutment surface, A folding mechanism for a rod-shaped member, in which rotation of the rod-shaped member in the folding direction is restricted by abutment between a rotation restriction surface provided at the tip of the lever member and the abutment surface, and by rotating the lever member against the biasing force of the spring member, the tip of the lever member moves away from the abutment surface, thereby allowing rotation of the rod-shaped member in the folding direction.

2. 2. A folding mechanism for a rod-shaped member as described in claim 1, wherein a gap adjustment means for adjusting the amount of gap between the one connecting member and the other connecting member is provided on the opposite side of the abutment by the lever member, across the normal line of the abutted surface passing through the axis of the first shaft.

3. When the rotation of the rod-shaped member is restricted, the tip of the lever member is accommodated in an internal space surrounded by the other connecting member and the other rod-shaped member to which the other connecting member is attached, and the lever member extends to the outside through an opening formed between the one connecting member and the other rod-shaped member, and an operating portion of the lever member is disposed outside the connecting member body, A folding mechanism for a rod-shaped member as described in claim 1, wherein, during the process of rotating the rod-shaped member in the folding direction, the operating portion of the lever member is brought closer to the first axis based on the biasing force of the spring member, so that the height from the first axis to the top of the operating portion becomes lower than the height from the first axis to the edge of the opening.

4. 2. The folding mechanism for a rod-shaped member according to claim 1, wherein a portion of the abutted surface of the other connecting member is formed of a separate, detachable second abutted member.

5. 5. The folding mechanism for a rod-shaped member according to claim 1, wherein the rod-shaped member is a rear rod-shaped member that supports a push handle of a wheelchair.

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