Wheelchair hand rim and method for manufacturing wheelchair hand rim

Abstract

To propose a hand rim for a wheelchair in which the joint strength with the wheel of the wheelchair can be improved, and the wheelchair can stably be used over a long term, and its manufacturing method.SOLUTION: A hand rim for a wheelchair includes a rim body 2 made by fiber reinforced plastic, and multiple mounting members 11 disposed at intervals in the circumferential direction of the rim body 2. The mounting member 11 includes an embedded part 13 embedded between layers of the reinforcing fibers of the fiber reinforced plastic for configuring the rim body 2, and a protrusion 12 protruded from the rim body 2. The hand rim 1 having such a configuration is improved in the joint strength between the rim body 2 and the mounting member 11. Also, as a manufacturing method of such hand rim 1, there are included a forming step of laminating the reinforcing fibers and a curing step of curing matrix resin. In the forming step, the embedded part 13 of the mounting member 11 is arranged between the layers of the reinforcing fibers.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a hand rim for use in a wheelchair and a method for manufacturing the hand rim. [Background technology]

[0002] Wheelchairs are fitted with hand rims on the drive wheels that are operated by the user to rotate the drive wheels. For example, Patent Document 1 proposes a hand rim made of fiber-reinforced plastic as such a hand rim. This conventional hand rim is made of fiber-reinforced plastic made of reinforcing fibers with excellent specific strength and specific elasticity, and therefore is capable of achieving both lightweight construction and mechanical properties (strength and rigidity). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-267905 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the hand rim of the conventional configuration described above is attached to a wheel (drive wheel) by screwing a shaft member protruding from the wheel into an insert nut attached to the hand rim. Here, the insert nut is inserted into a nut mounting hole formed in the hand rim after the hand rim is molded and fixed, and is usually fixed to the hand rim with an adhesive. In such a conventional configuration, when a user operates the hand rim, the shaft member and the insert nut that connect the hand rim and the wheel are easily subjected to load, and there is a risk that the insert nut will come off the hand rim due to relatively long-term use or the momentary action of a strong load, etc. Therefore, a configuration that can improve the joining strength between the hand rim and the wheel is required.

[0005] The present invention provides a hand rim for a wheelchair that can improve the joining strength with the wheel of the wheelchair and enable the wheelchair to be used stably for a long period of time, and a method for manufacturing the hand rim. [Means for solving the problem]

[0006] The first invention of the present invention is a wheelchair hand rim comprising a rim body molded into a hollow shape from a fiber-reinforced plastic consisting of reinforcing fibers and a matrix resin, and a plurality of mounting members provided on the rim body at predetermined intervals in the circumferential direction, the hand rim being attached to a wheelchair wheel via the mounting members, characterized in that the rim body is formed by laminating the reinforcing fibers that make up the fiber-reinforced plastic in the thickness direction, and the mounting members have embedded portions embedded between the layers of reinforcing fibers that make up the rim body, and protruding portions that protrude from the rim body and are fixed to the wheelchair wheel via a predetermined fixing means.

[0007] The reinforcing fibers may be carbon fibers, glass fibers, aramid fibers, etc. As the matrix resin, a thermosetting resin such as an epoxy resin or a phenolic resin is preferably used, but a thermoplastic resin such as a polyamide resin may also be used. The mounting member may be made of metal such as aluminum alloy, stainless steel, or steel, plastic, or fiber-reinforced plastic. Although bolts or screws are preferably used as fastening means, welding may also be used if the mounting member is made of the metal.

[0008] In this configuration, the embedded portion of the mounting member that is fixed to the wheel is embedded between the layers of reinforcing fiber that make up the rim body and is integrated with the rim body, so the joining strength between the rim body and the mounting member is extremely high. Therefore, when the hand rim of the present invention is attached to the wheel of a wheelchair, it has improved resistance to the load applied during use of the wheelchair, and damage due to relatively long-term use or the action of a strong load can be suppressed. Therefore, with the configuration of the present invention, the wheelchair can be used stably for a relatively long period of time.

[0009] The second invention of the present invention is a method for manufacturing a wheelchair hand rim of the first invention described above, comprising a forming step of forming a prototype of the rim body by stacking the reinforcing fibers in the thickness direction, and a hardening step of hardening the matrix resin combined with the reinforcing fibers that constitute the prototype of the hand rim, wherein the forming step includes a member placement step of placing embedded portions of the mounting members at predetermined intervals in the circumferential direction between the layers of reinforcing fibers stacked in the thickness direction.

[0010] Here, as the forming step, any of the following methods can be applied: a method of laminating prepregs in which reinforcing fibers are impregnated with a matrix resin, a method of laminating a base material of reinforcing fibers (such as a woven fabric), a method of aligning bundles of reinforcing fibers, wrapping them together, and laminating them. As the curing step, any of the following methods can be applied: a method using an autoclave, a method using a mold, a method using vacuum drawing, and the like.

[0011] In this manufacturing method, the embedded parts of the mounting member are positioned between the layers of reinforcing fiber in the forming step of laminating the reinforcing fibers to form the original body of the rim body, and then the matrix resin is hardened and molded in the hardening step, so that the mounting member can be molded integrally with the rim body. Therefore, this manufacturing method makes it possible to easily manufacture the hand rim of the first invention, which has an extremely high bond strength between the rim body and the mounting member. Effect of the Invention

[0012] As described above, the wheelchair hand rim of the present invention has an extremely high bond strength between the rim body and the mounting member, which prevents the bond between the rim body and the mounting member from being damaged by relatively long-term use or the momentary action of a strong load, etc. Therefore, a wheelchair equipped with the wheelchair hand rim of the present invention can be used stably for a relatively long period of time.

[0013] The method for manufacturing a wheelchair hand rim of the present invention can easily and stably manufacture the above-mentioned wheelchair hand rim. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing a mounting state of a hand rim 1 of the embodiment and a wheel 51 of a wheelchair. [Diagram 2] FIG. 2 is a vertical cross-sectional view showing the attachment state of the hand rim 1 and the wheel 51. [Diagram 3] FIG. 2 is a perspective view in which the hand rim 1 and the wheel 51 are separated. [Figure 4] FIG. [Diagram 5] 1A is a front view, FIG. 1B is a side view, and FIG. [Figure 6] 2A to 2C are explanatory diagrams showing a manufacturing process of the hand rim 1. [Figure 7] 1A is a front view, FIG. 1B is a side view, and FIG. 1C is a perspective view of a mounting member 41 of another example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An embodiment of the present invention will be described with reference to the accompanying drawings. A wheelchair (not shown) has a hand rim 1 attached to a drive wheel, which the user can turn when the wheelchair is moving. As shown in Figures 1 to 3, the hand rim 1 is attached to a wheel 51 that constitutes a drive wheel, and can rotate the drive wheel by being turned. Note that the tire attached to the wheel 51 and the spokes that constitute the wheel 51 can be the same as those of the past, so illustration and description thereof will be omitted.

[0016] The wheel 51 includes a pair of left and right flanges 52 that support the sidewalls of the tire, and a rim recess 53 that is connected between the flanges 52, 52. A plurality of rim-side mounting pieces 55 for mounting the hand rim 1 are arranged at predetermined intervals in the circumferential direction on the inner peripheral surface of the rim recess 53. The rim-side mounting piece 55 is substantially plate-shaped and includes a rim contact portion that contacts the inner peripheral surface of the rim recess 53 and a protruding portion that extends outward from the rim contact portion. An attachment hole (not shown) is formed through the rim contact portion, and an attachment hole 56 is formed through the protruding portion. The rim-side mounting piece 55 is fixed to the rim recess 53 by an attachment bolt 58 that is inserted through the attachment hole of the rim contact portion and a through hole (not shown) that penetrates the rim recess 53.

[0017] Meanwhile, the hand rim 1 comprises an annular rim body 2 and a number of mounting members 11 fixed to the rim body 2 at predetermined intervals in the circumferential direction. Here, the mounting members 11 are attached to rim side mounting pieces 55 arranged on the wheel 51, and are provided at circumferential positions corresponding to the rim side mounting pieces 55 in the same number.

[0018] The rim body 2 of the hand rim 1 is formed into a hollow shape from carbon fiber reinforced plastic (hereinafter referred to as CFRP) which is a composite of carbon fiber and matrix resin. In the rim body 2 of this embodiment, as described later, a predetermined number of woven fabric prepregs, in which carbon fiber fabric is impregnated with matrix resin, are laminated, and the rim body 2 is formed into a thin and hollow shape. In this embodiment, epoxy resin (thermosetting resin) is used as the matrix resin. Note that the carbon fiber corresponds to the reinforcing fiber according to the present invention.

[0019] As shown in Figures 2 and 4, the rim body 2 is composed of an outer ring portion 3 on the radially outer side and an inner ring portion 4 connected radially inward from the outer ring portion 3, with the outer ring portion 3 being formed with a wider width in the axial direction perpendicular to the radial direction than the inner ring portion 4. The axial outer surface of the outer ring portion 3 and the axial outer surface of the inner ring portion 4 are connected uniformly, while the axial inner surface of the outer ring portion 3 and the axial inner surface of the inner ring portion 4 are connected via an inclined peripheral surface portion 5. A rim body 2 configured in this way with an outer ring portion 3 and inner ring portion 4 makes it easier for a user to grip and operate the rim body 2.

[0020] 5, the mounting member 11 is formed by bending a flat rectangular piece, and is composed of a protruding portion 12 fixed to the rim-side mounting piece 55, and an embedded portion 13 bent from one side edge of the protruding portion 12. An elongated insertion hole 14 is formed through the protruding portion 12, and a circular resin insertion portion 15 is formed through the embedded portion 13 in the plate thickness direction.

[0021] The mounting member 11 is integrated with the rim body 2 by embedding the embedded portion 13 in the inclined peripheral surface portion 5 of the rim body 2 as shown in FIG. 2. That is, the rim body 2 is formed by laminating woven fabric prepregs as described above, and when the rim body 2 is molded, the embedded portion 13 of the mounting member 11 is embedded between the layers of the woven fabric prepregs, and the matrix resin of the prepregs is cured to form the mounting member 11 as an integral part. The embedded portion 13 of the mounting member 11 is embedded in the rim body 2, and the protruding portion 12 of the mounting member 11 protrudes from the rim body 2 in the axial direction. Here, the matrix resin penetrates into the resin insertion portion 15 of the embedded portion 13 of the mounting member 11 and is cured, so that an anchor effect is generated and the mounting member 11 is firmly integrated with the rim body 2.

[0022] As shown in Fig. 3, the hand rim 1 of this embodiment is attached to the wheel 51 by fastening each mounting member 11 to each rim-side mounting piece 55 of the wheel 51. More specifically, the protruding portion 12 of each mounting member 11 arranged on the rim body 2 is opposed to each rim-side mounting piece 55 of the wheel 51, and the insertion hole 14 of the protruding portion 12 is aligned with the mounting hole 56 of the rim-side mounting piece 55. In this state, the mounting bolt 21 is inserted through the insertion hole 14 and the mounting hole 56, and the mounting bolt 21 and the mounting nut 22 are screwed together, and the mounting member 11 and the rim-side mounting piece 55 are fastened together by the fastening action of the mounting bolt 21 and the mounting nut 22. In this way, the hand rim 1 is attached to the wheel 51 by fastening each mounting member 11 to each rim-side mounting piece 55 of the wheel 51. In this embodiment, the mounting bolt 21 and the mounting nut 22 correspond to the fastening means according to the present invention.

[0023] Next, a method for manufacturing the hand rim 1 of the present embodiment will be described. In this embodiment, the method for manufacturing the hand rim 1 is the internal pressure molding method known as a method for manufacturing CFRP products.

[0024] The manufacturing process for producing the hand rim 1, as shown in Fig. 6, involves sequentially performing the following steps: a forming step in which the woven prepreg is laminated on an internal pressure applying body such as a thermoplastic resin tube to form an original body (preform), a setting step in which the original body is set in the cavity of a mold, a curing step in which high-pressure gas is injected into the internal pressure applying body of the original body and the mold is heated, and a finishing step in which the surface shape of the molded product removed from the mold is adjusted. Each of these steps is described below.

[0025] In the forming process, the original body is formed by stacking and attaching woven prepregs cut into a predetermined shape to the outer surface of the internal pressure applying body. In the forming process of this embodiment, the mounting member 11 is arranged with a predetermined number of woven prepregs attached. At this time, the mounting member 11 is arranged with its embedded portion 13 placed on the surface of the woven prepreg attached to the internal pressure applying body. Thereafter, a further predetermined number of woven prepregs are stacked and attached, and the embedded portion 13 of the mounting member 11 is covered with the prepreg. Here, the position at which the mounting member 11 is arranged is determined by the radial position at which the embedded portion 13 of the mounting member 11 is embedded in the inclined peripheral surface portion 5 of the hand rim 1 and a circumferential position at a predetermined interval in the circumferential direction. In the original body formed in this forming process, the protruding portion 12 of each mounting member 11 protrudes from its surface. Incidentally, the step of arranging the embedded portion 13 of the mounting member 11 during lamination of the woven fabric prepregs corresponds to the member arranging step according to the present invention.

[0026] In the setting step, the original body formed in the forming step is set in a cavity of a mold. Here, the mold has a cavity formed to have the external shape of the hand rim 1, and this cavity is further formed with fitting holes into which the protruding parts 12 of the mounting members 11 protruding from the original body can be fitted. In the setting step, the original body is set in the cavity by fitting the protruding parts 12 of the mounting members 11 of the original body into the fitting holes of the cavity.

[0027] In the curing process, as described above, gas is injected at a predetermined pressure into the internal pressure applying body of the original body set in the cavity. Then, the mold is heated and maintained at a predetermined temperature. In this curing process, the matrix resin of the prepreg that constitutes the original body penetrates into the resin fitting portion 15 of each mounting member 11 and hardens. Note that the pressure of the gas injected into the internal pressure applying body, the heating temperature of the mold, the heating time, and other curing conditions are appropriately set according to the specifications of the woven prepreg (the basis weight of the carbon fiber and matrix resin) and the number of layers of the woven prepreg (the thickness of the hand rim 1), etc.

[0028] In the finishing process, burrs present on the molded product removed from the mold are removed to smooth the surface shape, etc. In this manner, the hand rim 1 of this embodiment is molded.

[0029] As described above, the hand rim 1 of this embodiment has an extremely high joint strength between the mounting member 11 and the rim body 2, since the embedded portion 13 of the mounting member 11 for mounting to the wheel 51 is embedded in the rim body 2 and molded integrally with the rim body 2. In particular, the matrix resin constituting the rim body 2 penetrates into the resin fitting portion 15 of the mounting member 11 and hardens, so that the mounting member 11 can be more firmly joined to the rim body 2 by its anchor effect. As a result, it is possible to exhibit high resistance to the load applied during use of the wheelchair, and it is possible to prevent the joint between the mounting member 11 and the rim body 2 from being damaged due to relatively long-term use or the action of a strong load. In other words, the hand rim 1 of this embodiment is made of CFRP, which has excellent specific strength and specific elastic modulus, and therefore, in addition to being lightweight while having the desired strength and rigidity, it is also possible to prevent the occurrence of the above-mentioned damage.

[0030] The manufacturing method of this embodiment is a method for manufacturing the hand rim 1 by the internal pressure molding method as described above, and in the forming step of laminating woven prepregs on an internal pressure applying body to form an original body (preform), the mounting member 11 is disposed and embedded between the overlapping woven prepregs, and then a setting step, a curing step, and a finishing step are carried out in sequence to form the hand rim 1 of this embodiment. The hand rim 1 thus manufactured has the embedded portion 13 of the mounting member 11 embedded in the rim body 2, and the mounting member 11 and the rim body 2 are joined extremely firmly. Therefore, according to the manufacturing method of this embodiment, the hand rim 1 of this embodiment can be stably manufactured, which has the above-mentioned effect of preventing damage to the joint between the mounting member 11 and the rim body 2.

[0031] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present invention. For example, the rim body 2 in the embodiment is configured to be composed of an outer ring portion 3 and an inner ring portion 4, but this is not limited to this and the shape of the rim body 2 can be changed as appropriate. For example, it may be in the shape of a circular ring with a cylindrical cross section, or it may be in the shape of a roughly rosary with enlarged and reduced diameter portions repeatedly connected together. In addition, in the embodiment, the mounting member 11 of the hand rim 1 is fixed to the rim side mounting piece 55 of the wheel 51, but this is not limited thereto, and the mounting member 11 of the hand rim 1 may be fixed directly to the rim recess 53 of the wheel 51 by a bolt or the like. Furthermore, the number of mounting members 11 provided on the hand rim 1 can be changed as appropriate. In the embodiment, the hand rim 1 is made by laminating woven prepregs, but the present invention is not limited to this, and may be made by laminating unidirectional prepregs in which carbon fibers are aligned in one direction. Even when such unidirectional prepregs are used, the hand rim can be molded by the internal pressure molding method in the same manner as in the embodiment. In addition, in the embodiment, prepreg is used to manufacture the hand rim 1, but the present invention is not limited to this. For example, an RTM molding method can be used in which carbon fiber woven sheets (not impregnated with matrix resin) or unidirectional sheets (not impregnated with matrix resin) are laminated, and the matrix resin is injected into a mold and cured. Alternatively, a filament winding method can be used in which a bundle of carbon fibers is wound. In any of these manufacturing methods, a hand rim 1 similar to that of this embodiment can be manufactured by arranging the mounting member 11 at a predetermined position during the carbon fiber lamination. In the present embodiment, the hand rim is made of carbon fiber as a reinforcing fiber, but the present embodiment is not limited to this, and glass fiber or aramid fiber can also be used. Furthermore, in the present embodiment, the hand rim is made of epoxy resin as a matrix resin, but the present embodiment is not limited to this, and phenol resin (thermosetting resin) or polyamide resin (thermoplastic resin) can also be used.

[0032] Also, the shape of the mounting member 11 can be changed as appropriate, so long as it includes the embedded portion 13 and the protruding portion 12. Furthermore, the form of the resin fitting portion 15 of the embedded portion 13 can also be changed as appropriate. For example, in the embodiment, a circular hole penetrating the embedded portion 13 in the plate thickness direction is used, but this is not limited to this, and the hole can be of another shape (e.g., rectangular, etc.). Furthermore, the resin fitting portion can be formed by cutting out the side edge of the embedded portion 13, or can be recessed in the plate thickness direction on at least one of the front and back sides of the embedded portion 13. Furthermore, it is also possible that the embedded portion 13 does not have a resin fitting portion formed therein. Here, a specific example of the mounting member 41 is shown in FIG. 7. This mounting member 41 has resin fitting portions 45, 45 cut into a semicircular arc shape formed on both sides of the embedded portion 13. Even with this configuration, the matrix resin of the prepreg penetrates and hardens inside the resin fitting portions 45, 45 of the embedded portion 13, so that an anchor effect is generated as in the above-mentioned embodiment, and the mounting member 41 is firmly integrated with the rim body 2. Note that the mounting member 41 of the other example has a configuration in which notched resin fitting portions 45, 45 are formed instead of the circular hole-shaped resin fitting portion 15 formed through the mounting member 11 of the above-mentioned embodiment, and the rest of the configuration is the same as the embodiment, so the same components are denoted with the same reference numerals and their explanations are omitted. [Explanation of symbols]

[0033] 1 Hand rim 2 Rim body 3 Outer ring 4 Inner Ring 5 Slanted peripheral surface 11 Mounting material 12 Protruding part 13 Buried section 14 Insertion hole 15 Resin fitting part 21 Mounting bolt (fastening means) 22 Mounting nut (fastening means) 41 Mounting material 45 Resin fitting part 51 Wheels 52 Flange 53 Rim recess 55 Rim side mounting piece 56 Mounting hole 58 Mounting bolt

Claims

1. A rim body formed in a hollow shape from fiber-reinforced plastic made of reinforcing fibers and a matrix resin; A plurality of mounting members are provided on the rim body at predetermined intervals in the circumferential direction. A hand rim for a wheelchair, which is attached to a wheel of the wheelchair via the attachment member, The rim body is formed by laminating reinforcing fibers constituting the fiber reinforced plastic in a thickness direction, The mounting member is An embedded portion embedded between layers of reinforcing fiber constituting the rim body; a protruding portion protruding from the rim body and fastened to the wheel of the wheelchair via a predetermined fastening means; The embedded portion and the protruding portion are integrally formed as a flat rectangular piece, Furthermore, the embedded portion is provided with a resin insertion portion that penetrates in the plate thickness direction and into which the matrix resin penetrates.

2. The mounting member is 2. The hand rim for a wheelchair according to claim 1, wherein the rectangular piece is bent from one side edge of the protruding portion, and the embedded portion is connected to the one side edge.

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