JP2006088891A - Caster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remarkably increase silentness and road surface impact absorbing property and reduce cost when a caster is running. <P>SOLUTION: The caster is mounted in such a way that a mounting interval of both supporting parts of a base part of a bracket arm and a base part of a spring is positioned in an angle range of 15-35 with a wheel center as a basic point in the bracket which rotatably supports a basic part of a spring which is installed between a top end of the arm and a hinge arranged near at the top end. Accordingly, amplitudes in front and rear (running) directions in running as well as impact absorbing width in vertical direction are made sufficient in spite of simple structure, and the silentness and road surface impact absorbing property are remarkably improved. A reduction of cost is realized by a reduction of turning radius and compact and simple constitution. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention, for example, a variety of moving equipment for use in hospitals such as stretchers and barges, or general-purpose wheelchairs, strollers, and other precision parts and equipment transportation carts used in factories. A caster suitable for use in a conveying means that requires low vibrations is intended to significantly improve quietness and road surface shock absorption during traveling and to reduce costs.

  As a caster having a structure that absorbs an impact from the road surface, for example, when a link to which a wheel is attached is coupled to a bracket of a carriage, the base end portion of the link is connected to the rotation axis of the briquette. By connecting a rubber member that is torsionally deformed as the link swings and a hydraulic damper is interposed between the bracket and the link body, the torsion spring characteristics of the rubber bush and the hydraulic damper are connected. An invention of a caster is disclosed in which the shock-absorbing characteristics of the link main body are mitigated by the shock-absorbing characteristics of the vehicle and the shock caused by the change in the road surface is attenuated and the tilting motion of the link body is attenuated (see Japanese Patent Laid-Open No. 2000-225803).

  In addition, a rotating body is rotatably provided at the lower part of the vehicle body, one end of the arm is coupled to the rotating body so that the arm can be rotated obliquely downward, and a wheel is attached to the lower part of the arm. A caster having a structure in which an impact from a road surface is buffered by providing a rotational displacement limiting mechanism that restricts the rotational displacement of the arm between the bearing portion of the rotating body and the arm is known (Japanese Patent Laid-Open No. 2000-135901). Issue gazette).

Furthermore, the second wheel on the front side in the running direction floats with respect to the carriage with the substantially V-shaped arm body having the first and second wheels on the two arms so as to form two rows in the traveling direction, and the first on the rear side. There is also known a caster that is swingably mounted via a rubber bush having a restoring force so that the wheel comes into contact with the ground (see Japanese Patent Laid-Open No. 2000-326701).
JP 2000-225803 A JP 2001-135901 A JP 2000-326701 A

  However, the one disclosed in Patent Document 1 uses a hydraulic damper mechanism, a torsionally deformed rubber, a lock mechanism using a "<"-shaped lever, and the structure becomes complicated, and an increase in cost is inevitably avoided. In addition, the shock absorption in the front-rear (running) direction is not sufficient. Furthermore, the thing of patent document 2 has almost no vibration relaxation of the front-back (running | running | working) direction on the structure, and it is necessary to lengthen the length of an arm to some extent, Therefore, the enlargement of components as a whole cannot be avoided. Moreover, since the number of parts increases, an increase in cost is inevitable.

  Furthermore, since the thing of patent document 3 is equipped with two front and back wheels which are two rows in the advancing direction, an enlargement is inevitably avoided, and it is unsuitable as a small caster, and the structure is complicated. Therefore, an increase in cost is inevitable. Further, when traveling on a relatively large stepped road surface, if the front wheel comes in contact with the ground, there is a risk of receiving an extremely large impact, which is not practical.

  Therefore, the present invention solves the above-mentioned problems, has a simple structure, and not only the vertical (up and down) direction, but also sufficient shock absorption in the front and rear (running) direction that occurs when passing through a stepped portion, reducing running vibration, In addition, it is intended to improve quietness, specifically, a base of an arm with a wheel attached to the tip, and a base of a spring interposed between the tip of the arm or a hinge near the tip; In the bracket for pivotally supporting the bracket, the mounting interval between the support bases of the base of the bracket and the base of the spring is located within an angle range of 15 to 35 degrees with the wheel center as the base point. On casters attached to

  As described above, the present invention provides a bracket that rotatably supports a base portion of an arm having a wheel attached to the tip and a base portion of a spring interposed between the tip of the arm or a hinge portion near the tip. The structure is simple because the mounting interval between the support portions of the base portion of the bracket arm and the base portion of the spring is set so as to be within an angle range of 15 degrees to 35 degrees with the wheel center as the base point. In spite of this, not only the impact in the vertical (up and down) direction during running but also the amplitude in the front and rear (running) direction is increased to sufficiently absorb the impact in the front and rear direction, and not only quietness but also road impact absorption. The cost can be reduced because the turning radius can be reduced, the turning radius can be reduced, and the structure can be made compact and simple.

  The specific contents of the present invention will be described below based on the embodiment of FIGS. 1 and 2. FIG. 1 is a side view showing the entire caster as an embodiment of the present invention, and FIG. FIG. 1 is a cross-sectional view taken along lines AA ′ and BB ′ in FIG. In FIG. 1, reference numeral 1 denotes a bracket attached to various kinds of moving tools and carts, 4 denotes an arm having a wheel 6 attached to the tip, and 7 denotes a coiled spring.

  The bracket 1 is formed by press-molding a thick metal plate so that the cross section has a U-shaped cross section, and the back (upper surface) can be attached to a moving tool, a carriage, etc. by screwing or welding, etc. Between the left and right sides of the arm, a pin for pivotally supporting the base of the arm 4 and the base of the spring 7 is spanned at a fixed interval, and the base support 2 of the arm and the base support of the spring 3 is formed.

  Further, the arm 4 is mounted with the base portion supported by the above-described base support portion 2, the front end direction thereof being directed substantially downward, and the wheel 6 is attached to the front end. That is, a portion near the tip of the arm 4 is bent into a “<” shape to form a bent portion 4a, and a cylindrical hub 5 having both ends oriented in the horizontal direction is attached to the tip, and the hub Wheels 6 and 6 which are double-wheeled by hub bolts 5a and 5a are rotatably attached to both left and right ends of 5.

  In the figure, 4b represents a hinge portion formed between the bent portion 4a and the hub 5. The spring 7 has a coil shape, and a cylindrical body 8 having a somewhat larger inner diameter is formed at the end portion on the bracket 1 side, and an inner diameter is somewhat smaller at the end portion on the hinge section 4b side, along the inner side of the cylindrical body 8 described above. Removable cylinders 9 are respectively attached to the cylinders 8, and mounting members 8 a and 9 a project from the cylinders 8 and 9 outward in the longitudinal direction.

  In the spring 7 having such a configuration, the base portion is rotatably supported by the base support portion 3 of the bracket 1 by the mounting bracket 8a, and the tip portion is rotatably attached to the hinge portion 4b of the arm 4 by the pin 10.

  Further, with respect to the mounting interval between the support portions 2 and 3 of the base portion of the arm of the bracket 1 and the base portion of the spring 7, as shown in FIG. 1, the base support portion 2 of the arm 4 is based on the center O of the wheel 6. If the angle between the line A-A 'connecting the center of the spring and the line B-B' connecting the center of the base support portion 3 of the spring 7, that is, the angle connecting A-O-B is less than 15 degrees, the shock absorbing ability in the vertical direction In contrast, when the angle exceeds 35 degrees, the shock absorbing ability in the vertical direction is improved, but the shock absorbing ability in the front-rear (running) direction is lowered.

  Therefore, in order to secure the shock absorbing capacity in the vertical direction while maximizing the shock absorbing capacity in the front-rear (running) direction, both support parts of the base part of the bracket 1 and the base part of the spring 7 are used. Regarding the mounting interval between 2 and 3, it is preferable that the mounting is performed so that the angle connecting A-O-B is within the range of 15 to 35 degrees.

  In this case, the tip of the spring 7 is attached not in the center (O) of the wheel 6 but in the middle of the bent portion 4a of the arm 4 as in the present embodiment shown in FIG. In some cases, strictly speaking, it is not the angle itself connecting A-O-B, but including the case where the arm 4 is curved, if it is closer to the tip of more than three-quarters of the total length of the arm 4, Even in the case where the tip of the spring 7 is attached near the tip of the arm 4 in that sense, the angle connecting the A-O-B is substantially the same. Even if considered equally, there is not much difference in terms of effect.

  In the above configuration, when the rear side of the bracket 1 is attached to various moving tools or carts and travels in the travel direction indicated by the arrows in FIG. 1, the wheels are affected by the impact received by the wheels when passing through the uneven portions of the road surface. 6 moves diagonally upward and left together with the arm 4 with the base support portion 2 of the arm 4 as a fulcrum. At this time, since the spring 7 interposed between the arm 4 and the hinge portion 4b near the tip is pressed and repels downward, the wheel 6 does not move more than necessary.

The side view of the caster which is an Example of this invention. Sectional drawing in the AA 'line (A) and BB' line (B) in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bracket 2 Arm base support part 3 Spring base support part 4 Arm 4a Bending part 4b Hinge part 5 Hub 5a Hub bolt 6 Wheel 7 Spring 8 Cylindrical body 8a Mounting bracket 9 Cylindrical body 9a Mounting bracket 10 Pin

Claims (4)

  In a bracket that rotatably supports a base portion of an arm having a wheel attached to the tip and a base portion of a spring interposed between the tip of the arm or a hinge portion near the tip, the base portion of the arm of the bracket and the spring The caster is attached so that the attachment interval between the center of both support parts and the base of the wheel is within the range of 15 to 35 degrees with the wheel center as the base point.   The caster according to claim 1, wherein the wheel attached to the tip of the arm is a double wheel.   The caster according to claim 1, wherein at least a portion near the tip of the arm is bent into a substantially L shape or a "<" shape.   The caster according to claim 1, wherein the arm is curved from the base portion toward the distal end.

Images