1. Field of the Invention
The present invention relates to a resin coil spring and a method of manufacturing the resin coil spring.
2. Description of the Related Art
Conventionally, a reagent container employed in an automated analyzer includes a metallic compression spring in a cap. A used reagent container must be disposed as medical waste. However, when a main body of the reagent container is made of synthetic resin, the reagent container cannot be disposed as it is unless the metallic compression spring is removed. One way to solve this problem is to use a resin spring which is used in a liquid-filling pump with a push-down head and the like instead of the metallic compression spring (see, for example Japanese Patent Application Laid-Open No. H10-73138).
A method of manufacturing a resin coil spring according to one aspect of the present invention includes integrally molding a spring unit from synthetic resin, the spring unit including a coil unit having plural coil members and ring-like supports respectively arranged on two sides of the coil unit and connected to an end of each of the plural coil members, and stacking the molded spring units one on another.
A resin coil spring according to another aspect of the present invention includes plural spring units each integrally molded from synthetic resin and stacked one on another, the spring unit including a coil unit having plural coil members, and ring-like supports respectively arranged on two sides of the coil unit and connected to an end of each of the plural coil members.
The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.
A method of manufacturing a resin coil spring and a resin coil spring according to a first embodiment of the present invention will be described in detail below with reference to the accompanying drawings.
A resin coil spring 1 includes, as shown in
Here, when the pitch angle is wider than 20° or the number of turns is larger than ½ turn, the spring force of the spring unit 2 can be increased. In this case, however, the coil member 2c of the spring unit 2 tends to bulge in a radially outward direction about the central axis when being compressed. When the coil member 2c bulges in this manner, an outer circumferential portion of the coil member 2c is brought into contact with a wall or the like of an object for which the spring unit 2 is employed depending on the type of the object. Then, the spring unit 2 cannot work as a spring. Or, the spring unit 2 cannot exert sufficient spring force because of the friction between the outer circumferential portion of the coil member 2c and the wall or the like. However, if the coil member 2c has an excessively narrow pitch angle and an excessively small number of turns, the spring unit 2 cannot have a required spring force.
The resin coil spring 1 configured as described above is manufactured from two spring units 2 each molded integrally and stacked one on another so that the holes 2d engage with the corresponding bosses 2e respectively as shown in
Next, a method of manufacturing a resin coil spring and a resin coil spring according to a second embodiment of the present invention will be described in detail with reference to the accompanying drawings. The resin coil spring 1 of the first embodiment is manufactured from two left-handed spring units 2 stacked one on another. On the other hand, the resin coil spring of the second embodiment is manufactured from one left-handed spring unit 2 and one right-handed spring unit placed one on another.
The resin coil spring 5 includes a left-handed spring unit 2 and a right-handed spring unit 4 each integrally molded from synthetic resin such as polyacetal as shown in
The resin coil spring 5 configured as described above is easily manufactured from the spring unit 2 and the spring unit 4 each integrally molded and placed one on another so that the bosses 2e engage with the corresponding holes 4d, as shown in
When the spring unit 2 or the spring unit 4 has a pitch angle exceeding 20°, and if the stress works on the spring unit 2 or 4 to cause expansion or contraction, the support 2b or the support 4b may rotate in the circumferential direction in accordance with the direction of winding of the coil members 2c or 4c. When the spring unit 2 and the spring unit 4 having different directions of winding are placed one on another and combined as in the resin coil spring 5, even if the support 2b or the support 4b rotates in the circumferential direction at the time of expansion or contraction, the rotations are in opposite directions. Therefore, the rotations of the supports 2b and 4b offset with each other. Thus, the resin coil spring 5 can prevent the friction resistance caused by the rotation of the supports 2b and 4b from negatively affecting the expansion and contraction of the coil members 2c and 4c, whereby the resin coil spring 5 can sufficiently work as a spring. Therefore, when the spring units with different directions of winding are combined in the resin coil spring of the present invention, preferably an even number of spring units are combined.
A method of manufacturing a resin coil spring and a resin coil spring according to a third embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The resin coil springs 1 and 5 of the first and the second embodiments are short resin coil springs made from two spring units stacked one on another. On the other hand, the resin coil spring of the third embodiment is a long resin coil spring wherein five spring units including the left-handed spring units 2 and the right-handed spring units 4 are stacked.
The resin coil spring 10 includes two left-handed spring units 2 and three right-handed spring units 4 as shown in
In the resin coil spring 10, when the coil members 2c and 4c of the adjacent spring units 2 and 4 have different directions of winding, and an odd number of spring units including spring units 2 and 4 are stacked one on another, the rotations of the supports 2b and 4b of the adjacent spring units 2 and 4 are offset with each other. In the resin coil spring 10 in which an odd number of spring units 2 and 4 are stacked one on another, the number of spring units 4 is larger than the number of the spring units with a different direction of winding by one. Therefore, the pitch angle of the coil member 4c of one spring unit 4 is set equal to or narrower than 20°, so as to prevent the rotation of the supports 4b of the spring unit 4. Thus, the resin coil spring 10 can prevent the rotation of the support 4b attributable to the spring units 4 whose number is larger than the other spring units by one. In the resin coil spring 10, the pitch angle of the coil members 2c and 4c of all the spring units 2 and 4 stacked one on another may be set equal to or narrower than 20°.
As is obvious from the description of the resin coil springs 1, 5, 10 of the first to the third embodiments, the method of manufacturing the resin coil spring according to the present invention includes a step of integrally molding a spring unit from synthetic resin, and a step of stacking a plurality of the molded spring units one on another. The resin coil spring of the present invention is manufactured from plural spring units stacked one on another. Therefore, the resin coil springs of the present invention can be manufactured from any number of spring units stacked one on another depending on the required length, as far as the diameters of the spring units are the same. Preparing two types of spring units, namely, the left-handed spring units and the right-handed spring units in advance should be sufficient. Thus, according to the method of manufacturing the resin coil spring and the resin coil spring of the present invention, it is not necessary to prepare a metal mold for each size of the resin coil spring. Therefore, a resin coil spring of a required length can be provided at low cost, and resin coil springs of various lengths can be readily manufactured.
The resin coil spring of the present invention may be integrally molded from synthetic resin, and configured as a resin coil spring 15 shown in
Thus, as can be seen from the foregoing, since the method of manufacturing the resin coil spring according to the present invention includes a step of integrally molding a spring unit from synthetic resin, and a step of stacking the molded spring units one on another, and the resin coil spring according to the present invention is manufactured from plural spring units stacked one on another, resin coil springs of different lengths and the same diameter can be easily manufactured, and resin coil springs of different lengths can be provided at low cost.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2005-232548 | Aug 2005 | JP | national |
This application is a continuation of PCT international application Ser. No. PCT/JP2006/315324 filed Aug. 2, 2006 which designates the United States, incorporated herein by reference, and which claims the benefit of priority from Japanese Patent Applications No. 2005-232548, filed Aug. 10, 2005 incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2006/315324 | Aug 2006 | US |
Child | 12026170 | US |