WO2004052662A1

WO2004052662A1 - Shock-cushioning caster

Info

Publication number: WO2004052662A1
Application number: PCT/JP2003/015638
Authority: WO
Inventors: Nobuchika Murata
Original assignee: Shishiku Adokuraisu Kabushiki Kaisha
Priority date: 2002-12-10
Filing date: 2003-12-05
Publication date: 2004-06-24
Also published as: AU2003289226A1; JPWO2004052662A1; JP3094703U

Abstract

A caster comprises a holding member (3) for rotatably supporting a wheel supported by a wheel shaft (8), a swing shaft (7) for swingably supporting the holding member at an installation member (2), limiting means (9) for limiting the swing of the holding member within a range from a start position at which the swing shaft and the wheel shaft of the wheel are aligned in a line in a direction substantially perpendicular to the direction of a tangential line on the wheel and a surface on which the wheel rolls (15) to an end position at which the line is shifted by a predetermined angle, and a biasing member (11) for biasing the holding member toward the start position so as to position it at the start position. When the wheel rolls down or over a step, shock force received by the wheel is cushioned when the holding member swings, against biasing force from the biasing member, from the start point side to the end point side, and the wheel is moved by the swing toward the rear relative to an advance direction of the wheel. At this time, the wheel slightly moves up and down relative to the installation member; however, the amplitude of the up and down movement is small in comparison with the amount of movement of the wheel toward the rear relative to the advance direction of the wheel.

Description

Casters to reduce the impact

Technical field

TECHNICAL FIELD The present invention relates to a caster for buffering an external force applied to a wheel. Light

Background art

Conventionally, casters have been used as wheel devices for trolleys, wheelchairs, and the like, and various types have been proposed. Some of these casters have an impact when the wheels roll on the road or floor and go down a step, or when riding over a step.

, To absorb and mitigate the shock, that is, a buffer mechanism (buffer)

).

For example, U.S. Pat. No. 3,094,703 discloses a utility model registration by the present applicant.

FIG. 2 of 703) shows a caster with a buffer function. Although the gazette does not specifically disclose the shock absorbing mechanism of the caster, such casters mainly include an elastic panel (spring) having an elastic restoring force and a damper (attenuator).

) Is often used.

If a rotary type damper is adopted here,

A supporting bracket fastened to a vehicle such as a bogie, a low damper attached to the supporting bracket, and a swing bracket pivotally connected to the supporting bracket with one damper shaft of the rotary damper as a fulcrum axis. A wheel rotatably connected to the end of the swing bracket via an axle and an elastic panel interposed between the support bracket and the swing bracket so as to be extendable and contractible are provided.

By the way, according to Cass Yuichi of the above publication, the straight line connecting the damper shaft (fulcrum shaft) of the rotary damper, which is the swing center of the swing bracket, and the axle that supports the wheels is approximately 45 to the vertical direction. ° It is inclined about. For this reason, from the fulcrum axis to the axle If the length of the axle is set to the distance L, the axle will shift from the fulcrum axis horizontally by approximately L · sin 45 °.

For example, according to such a caster, when the swing bracket swings about 20 ° around the fulcrum axis, a straight line connecting the fulcrum axis and the axle is inclined at about 65 ° with respect to the vertical direction. . As a result, when the swing bracket swings approximately 20 ° due to the vibration, the maximum amplitude of the vertical vibration of the wheel is approximately 40% of the height difference between the swing shaft and the axle when there is no vibration. Will also be reached.

In other words, the caster originally has a structure in which the wheel vibrates up and down greatly with respect to the support bracket, and if the damping action of the rotary damper cannot be obtained, the wheel is driven by the continuous expansion and contraction of the elastic panel. It vibrates greatly up and down.

Such vertical vibrations of the wheels are required to be reduced as much as possible because the greater the amplitude, the greater the impact on the occupants of the luggage and the wheelchair. Therefore, as described above, for the caster with a buffer function, a buffer function for attenuating the impact applied to the wheels by the mouth damper becomes effective.

For example, when the wheel is subjected to vibration or impact from unevenness of the road surface, the swing bracket is swung about the swing shaft with respect to the support bracket, and the elastic panel is expanded and contracted with the swing. On the other hand, the damper shaft of the rotary damper is rotated with the swing of the swing bracket, and this rotation generates a flow resistance of the working fluid in the rotary damper, thereby providing a damping action for suppressing the swing of the swing bracket. Can be This damping action absorbs the vibrations and shocks that the wheels have received from uneven road surfaces.

In this way, for a caster with a shock absorbing function, an attenuator such as a rotary damper can quickly converge the large amplitude vibration applied to the wheel, and the ブラケット continuous It seems that this is an effective means of suppressing vibration.

However, even with casters using the above-mentioned attenuators, as described above, since the wheel itself adopts a structure that vibrates up and down greatly, immediately after impact is applied to the wheels, There is a possibility that the wheel will sink with a large amplitude. In addition, since such a large sinking of the wheel is accompanied by a large acceleration, there is a problem that, in particular, a passenger in a wheelchair may give a great sense of discomfort or discomfort.

In addition, it is necessary to mount an attenuator such as a rotary damper in the structure of the casing, which may complicate the structure of the casing itself. However, there is also a problem that the failure frequency may be increased.

The present invention has been made in order to solve the above-mentioned problems, and a "caster for reducing impact" (hereinafter referred to as "caster for reducing impact") which can significantly suppress vertical vibration of wheels without using various dampers such as a rotary damper. (Referred to simply as “casters”). Disclosure of the invention

In order to achieve this object, a caster according to a first aspect of the present invention includes a wheel that can roll on a rolling surface, and a mounting member that attaches the wheel to an object, and supports an axle of the wheel. A holding member for rotatably holding the wheel, a rocking shaft for swingably supporting the holding member on the mounting member, and an axle for the rocking shaft and the wheel. The swinging motion of the holding member is within a range from a starting point position arranged in a direction substantially orthogonal to a tangential direction of a rolling surface to an end point position at which the axle of the wheel is displaced by a predetermined angle from the starting point position about the swing axis. Limiting means for restricting the movement, and urging the holding member, whose swing is restricted between the start point position and the end point position by the restricting means, toward the start point position so as to be positioned at the start point position. And a member.

According to the caster of the first invention, the attachment member is attached to an object (for example, a lower surface of a vehicle body of a bogie or a lower end of a front wheel support of a wheelchair) to be used as a wheel device of the object. At this time, the wheel is rolled with its outer peripheral surface in contact with a rolling surface such as a road surface or a floor surface. The rolling wheel is rotated with respect to the holding member about its own axle. At this time, the wheel is rolled so that the turning direction of the wheel coincides with the swinging direction from the start point side to the end point side of the holding member. Then, the holding member is made to be able to swing backward in the traveling direction of the object (ie, the caster) accompanying the rolling of the wheel.

Here, when the wheel goes down a step on a road surface or the like, the wheel collides with the road surface or the like and receives the impact force as an external force. When the wheel receives an external force, the holding member is swung about the swing axis from the starting point side toward the end point side relative to the mounting member while resisting the urging force of the urging member. . Due to this swing, the axle of the wheel draws an arc-shaped trajectory around the swing axis from a state where the axle and the swing axis of the wheel are arranged in a direction substantially perpendicular to the tangential direction of the wheel and the driven surface. The object is moved rearward in the traveling direction of the object with respect to the mounting member.

However, when the holding member reaches the end point position, further swing beyond the end point position is restricted by the restricting means. This restriction also restricts the movement of the wheel axle backward in the direction of travel of the object. Thereafter, if the impact force is not continuously applied, the holding member is urged by the urging force of the urging member, and moves in the opposite direction to the mounting member to swing toward the starting point position. It is moved to the original state.

As described above, when the holding member swings and the axle of the wheel is moved rearward in the traveling direction of the object with respect to the mounting member, the axle of the wheel follows an arc-shaped trajectory. The height difference from the wheel to the axle (vertical distance to the rolling surface) is also reduced. The amount of reduction in the height difference corresponds to the amount of change in the height difference (distance) from the mounting member to the contact point between the wheel and the driven surface.

Specifically, when the holding member is at the starting point side, if the distance from the wheel axle to the swing axis is distance L, the wheel axle moves rearward in the traveling direction with the swing of the holding member. Is the product of the sine function value of the angular displacement 0 of the holding member and the distance L (Δ Χ = L · sin 0). On the other hand, the distance Δ 移動 that moves in the vertical direction with respect to the rolling surface is a difference obtained by subtracting the product of the distance L and the cosine function value of the angular displacement の of the holding member from the above distance L (AY = L · (1— cos 0)).

Therefore, the distance Δ する that the wheel axle moves in the direction perpendicular to the rolling surface is smaller than the distance X that the wheel and its axle move rearward in the traveling direction if the angular displacement 0 is less than approximately 90 °. Always smaller. For example, if the position in which the end point position is substantially 2 0 ⁰ away from the start position of the holding member, the vertical movement of the wheel becomes less substantially 6% of the distance L mentioned above, contrast, horizontal movement of the wheel X Is approximately 34% of the distance L.

In other words, a wheel that moves up and down with respect to the mounting member in accordance with the swing of the holding member has a height of approximately 6% or less with respect to the height difference (that is, the distance L) between the swing axis and the axle of the wheel when there is no vibration. It only works. As a result, when the wheel rolls over a step on a road surface or the like, the vertical movement of the wheel with respect to the mounting member can be reduced, and the object is prevented from vibrating significantly up and down while traveling.

In the caster according to the second invention, in the caster according to the first invention, when the holding member is at the start point position, at least a part of the holding member and the attachment member may be connected to the holding member. When the holding member is at the end point position, at least a part of the holding member and the mounting member are swung toward the end point position of the holding member while the holding member is at the end point position. Butts in the direction.

According to the caster of the second invention, the caster operates in the same manner as the caster of the first invention. In addition, when the holding member swings toward the starting point, at least a part of the holding member is attached to the mounting member. By abutting at least a part of the sway, swing beyond its starting point is limited. On the other hand, when the holding member swings toward its end point position, at least a part of the holding member abuts at least a part of the mounting member, thereby restricting swinging beyond the end point position. .

The caster according to the third invention is the caster according to the first or second invention, The means includes: an engaging member provided on one of the holding member or the mounting member; a fitting member slidably fitted to the engaging member; and the other of the holding member or the mounting member and the swing shaft as a center. A starting end face, which is provided in an arc shape and is engaged with the engagement member when the holding member is at the start point position, and is engaged with the engagement member when the holding member is at the end point position. And a guide groove having an end surface.

According to the caster of the third aspect of the invention, the caster operates in the same manner as the caster of the first or second aspect of the invention, and further, when the holding member is swung about the swing shaft with respect to the mounting member, the engaging member Is relatively slid in the guide groove while being fitted in the guide groove. That is, the swing of the holding member is guided by the sliding of the engaging member in the guide groove.

Further, when the holding member reaches the starting point position, the engaging member abuts on the starting end face of the guide groove, and the abutment restricts the swinging movement of the holding member beyond the starting point position. On the other hand, when the holding member reaches the end position, the engaging member abuts on the end surface of the guide groove, and the abutment restricts the swing of the holding member from exceeding the end position.

A caster according to a fourth aspect of the present invention is the caster according to any one of the first to third aspects, wherein the biasing member has one end locked to the holding member or the mounting member in the vicinity of the swing shaft. A one-end locking portion, a bending portion extending from the one-end locking portion toward the swing shaft, and bent so as to straddle at least a part of an outer periphery of the swing shaft; An elastic body having an end that is folded at an angle of about 90 ° or less with respect to the one end engaging part and having the other end engaging part that is engaged with the other of the holding member or the mounting member; When the holding member is swung from the start point side to the end point side around the swing axis, the one end locking part side and the other end locking part are provided via the bending part. The angle with the side is reduced, and the urging force is generated with the reduction.

According to the caster of the fourth invention, the caster operates in the same manner as the caster of any of the first to third inventions, and the holding member is located on the starting point side with respect to the mounting member about the pivot axis. When the elastic body is swung toward the end point, the elastic body is elastically deformed in accordance with the swing, and the one end locking portion side and the other end locking portion are bent.

When the two locking portions are flexed, the angle between the two locking portions is reduced via the curved portion. As the angle decreases, the elastic body generates a restoring force due to the elastic deformation. The holding member is urged toward the starting point by the elastic restoring force of the elastic member.

Also, since the curved portion of the elastic body straddles the outer periphery of the swing shaft, when the one end locking portion side and the other end locking portion side of the elastic body are bent and deformed by the swing of the holding member. However, the curved portion is not crushed below the outer diameter of the swing shaft. Therefore, bending deformation of the elastic body at the one-end locking portion side and the other-end locking portion side causes excessive stress concentration in the curved portion, and the bent portion is prevented from being broken and broken.

A caster according to a fifth aspect of the present invention is the caster according to the fourth aspect, wherein one end of the elastic body is locked to the holding member in the vicinity of the swing shaft. The stop is wound and locked around the outer periphery of the engaging member, and the engaging member is provided as a part of the mounting member.

According to the caster of the fifth invention, the caster of the fourth invention operates in the same manner as the caster of the fourth invention, and the other end locking portion of the elastic body is wound around the engaging member sliding in the guide groove provided in the holding member. Since it is turned, the engaging member can also be used as a member for locking the other end locking portion of the elastic body to the mounting member.

A caster according to a sixth aspect of the present invention is the caster according to the fourth or fifth aspect, wherein the elastic body has a length from the curved portion to the one-end locking portion from the bent portion to the other-end locking portion. It is formed shorter than the length.

According to the caster of the sixth aspect of the present invention, in addition to the operation similar to that of the caster of the fourth or fifth aspect, the elastic body has a length from the curved portion to the one end locking portion. Since it is shorter than the length, the portion from the curved portion to the one-end locking portion is unlikely to bend and deform. That is, the external force applied to the part applied from the curved part to the one-end locking part is The bending moment applied to the curved portion can be reduced, and the elastic body can be given strong elasticity.

A caster according to a seventh aspect of the present invention is the caster according to any one of the first to third aspects, wherein the urging member includes an elastic body that is non-rotatably attached to the mounting member. At least a part of the shaft is non-rotatably passed through the inner periphery of the elastic body.

According to the caster of the seventh invention, the caster acts in the same manner as the caster of any of the first to third inventions. In addition, when the holding member is swung about the swing axis by the impact received by the wheel, the elastic body The swinging shaft, which is non-rotatably connected to the holding member, is rotated together with the holding member while elastically deforming the elastic body non-rotatably attached to the mounting member so as to twist. Due to the elastic deformation of the elastic body, the holding member is urged toward the starting point.

The caster according to an eighth aspect of the present invention is the caster according to the seventh aspect, wherein a part of the oscillating shaft has a substantially polygonal outer peripheral shape, and the elastic body has a substantially polygonal outer peripheral shape of the oscillating shaft. The mounting member is formed in a substantially cylindrical shape having an inner peripheral shape that matches the outer peripheral shape of the elastic body. Elastic member attaching portion.

The caster of the eighth invention operates in the same manner as the caster of the seventh invention, and furthermore, the outer peripheral shape of a part of the swing shaft and the inner peripheral shape of the elastic body are matched, and the outer peripheral shape of the elastic body is The inner peripheral shape of the elastic attachment portion of the mounting member is matched. In addition, since the elastic body conforms to both the swinging shaft and the elastic body attaching portion with a substantially polygonal inner or outer peripheral shape, the swinging shaft is the inner circumferential portion of the elastic body, and the elastic body is the elastic body. The inner periphery of the attachment portion is prevented from idling. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side view of a caster according to a first embodiment of the present invention, and illustrates a state where a swing bracket is at a start point position. FIG. 2 is a front view of the caster projected from the front side in the traveling direction of the wheel. FIG. 3 is a longitudinal sectional view taken along the line III-III in FIG. 2, and is a view showing a state where the swing bracket is at a start point position.

FIG. 4 is a vertical cross-sectional view taken along the line III-III in FIG. 2, and shows a state in which the swing bracket is at an end point position.

FIG. 5 (a) is a side view of the caster in a state where the swing bracket is at the start point position, and FIG. 5 (b) is a side view of the caster in a state where the swing bracket is at the end point position.

FIG. 6 is a side view of a caster according to the second embodiment.

FIG. 7 is a cross-sectional view illustrating the internal structure of the caster according to the second embodiment.

FIG. 8 is a side view of the caster when the swing bracket according to the second embodiment is at the end point position. Explanation of reference numerals

1, 20 Caster 0

2, 21 Supporting tool (part of mounting member)

3, 22 Swing bracket (holding member)

4 wheels

5 Porto (part of mounting member)

7, 23 Swing axis

8 axle (wheel axle)

9, 28 Guide groove (Guide groove, part of restriction means)

10, 25 Guide pins (part of the engaging member, part of the restricting means)

1 1 Urging member (elastic body, urging member)

1 1 a Locking part (one of the one-end locking part or the other-end locking part, one-end locking part)

1 1 b Curved section

9,

^ Locking part (one end locking part or the other end locking part, other end locking part) Buffer (part of locking member)

Rolled surface

Rectangular shaft (part of swing shaft)

Eight housing (elastic body attachment part, part of mounting member)

Shock absorber (elastic body, part of biasing member)

Angle (the angle formed by the one-end locking part side and the other-end locking part type) Best mode for carrying out the invention

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a side view of a casing 1 according to a first embodiment of the present invention, and illustrates a state where a swing bracket 3 is at a start point position.

The caster 1 is attached to an object (not shown) such as a wheelchair or a trolley, and is used as a wheel of the object. The object to which the caster 1 is attached is not limited to a wheelchair or a trolley, but can be used as a device for moving and carrying various heavy objects such as stretchers, beds, and pianos.

As shown in FIG. 1, the caster 1 mainly includes a support 2 attached to an object such as a wheelchair or a trolley, a swing bracket 3 that is swingably connected to the support 2, and a swing bracket 3. And a wheel 4 rotatably supported by the moving bracket 3. The support 2 has a shaft-like port 5 vertically suspended at a front portion (right side in FIG. 1) of an upper end portion (upper side in FIG. 1). The port 5 is supported by bearings 6, 6 (see FIG. 3) mounted inside the support 2, and is rotatably mounted on the support 2 via the bearings 6, 6. I have.

The support 2 is attached to the object via the port 5 and is turned around the center axis j (the dashed line on the right in FIG. 1) of the port 5 so as to be directed in the traveling direction of the wheel 4. It is configured to be.

Specifically, the central axis j of the port 5 is in a horizontal direction with respect to a straight line k (dashed line on the left side in FIG. 1) connecting the contact point P of the wheel 4 and the driven surface 15 with the axle 8. (Right direction in Fig. 1). Therefore, when the wheel 4 rolls and the caster 1 advances, the axle 8 of the wheel 4 always moves backward with respect to the port 5 in the traveling direction of the caster 1 (or the rolling direction of the wheel 4). ), The support 2 is rotated in a horizontal plane about the port 5 as a central axis.

FIG. 2 is a view in which the casters 1 are projected from the front side in the traveling direction of the wheels 4 (the right side in FIG. 1), that is, a front view of the casters 1. As shown in FIG. 1, the swing bracket 3 straddles the upper end of the support 2 and the rear part (the upper left side in FIG. 1).

As shown in FIG. 2, the swing bracket 3 includes a pair of side plates 3a and 3b that sandwich the right and left sides of the support 2 and the upper ends of the pair of side plates 3a and 3b The left and right ends of a top plate 3c placed on the upper end of the top plate 3c are integrally connected. The pair of side plates 3a and 3b are fastened with axial ends of a swing shaft 7, an axle 8 and a guide pin 10 to be described later, respectively, between the lower ends of the pair of side plates 3a and 3b. Is provided with wheels 4 supported by axles 8.

Returning to FIG. As shown in FIG. 1, the swing bracket 3 is formed in an inverted letter shape in a side view, and protrudes forward in the traveling direction of the caster 1 (the right side in FIG. 1). A swing shaft 7 is provided at a rear portion on the upper end side (the upper left side in FIG. 1) of the swing bracket 3, and the swing bracket 3 allows the swing bracket 3 to swing with respect to the support 2. It is pivoted. An axle 8 that pivotally supports the wheels 4 so as to be rotatable about the lower end of the swing bracket 3 (FIG. 1, lower left side) is located substantially vertically below the swing shaft 7. Is provided.

The wheel 4 is rotatable around the axle 8 with respect to the swing bracket 3. In the front part of the swing bracket 3 (the right side in FIG. 1), a part protruding forward in the traveling direction of the CAS 1 has a substantially arc-shaped long hole centered on the swing shaft 7. Guide grooves 9 are provided. That is, the guide groove 9 is a long groove extending in the same direction as the swing direction of the swing bracket 3.

The guide groove 9 is formed so as to penetrate in the width direction of the swing bracket 3 (perpendicular direction to the paper surface of FIG. 1 (or the horizontal direction of FIG. 2)). A guide pin 10 is fitted slidably.

3 and 4 are longitudinal sectional views taken along the line III-III in FIG. 2. In particular, FIG. 3 shows a state in which the swing bracket 3 is at the starting point position, as in FIG. 1, and FIG. The state where the moving bracket 3 is at the end point position is illustrated.

As shown in FIG. 3, the guide pin 10 is a shaft having a substantially circular cross-section when provided in the width direction of the support 2 (perpendicular to the plane of FIG. 1 (or the horizontal direction in FIG. 2)). And an axial end portion thereof is fitted into the guide groove 9. As described above, the guide groove 9 is a substantially arc-shaped long groove in a side view, and both ends in the longitudinal direction are closed.

Here, when the swing bracket 3 is swung clockwise from the position shown in FIG. 3 to the position shown in FIG. 4, the guide pin 10 is moved in the longitudinal direction of the guide groove 9 as shown in FIG. One end side (upper side in Fig. 4) is abutted against the inner peripheral end surface (termination surface), and this abutment restricts sliding in the guide groove 9. The abutment of the guide pin 10 causes the swing bracket 3 Is limited in the clockwise swing of Fig. 4.

On the other hand, when the swing bracket 3 is swung counterclockwise from the position shown in FIG. 4 to the position shown in FIG. 3, the guide pin 10 is moved into the guide groove 9 as shown in FIG. The inner peripheral end face (start end face) at the other end side in the longitudinal direction (the lower side in FIG. 3) is abutted, and sliding in the guide groove 9 is restricted by this abutment. The butting of the guide pins 10 limits the swinging of the swing bracket 3 in the counterclockwise direction in FIG.

As described above, the range of movement of the guide pin 10 is restricted by the guide groove 9, so that the swing range of the swing bracket 3 is limited to a predetermined angle range. Specifically, the swing range of the swing bracket 3 is determined by the guide pins 10 as shown in FIG.

1 2

, \ As shown in Fig. 4, the guide pin 10 extends in the longitudinal direction of the guide groove 9 from the position where the guide groove 9 abuts on the inner peripheral end surface at one end in the longitudinal direction (the lower side in Fig. 3). Between the other end (the upper side in Fig. 4) and the position where it abuts on the inner peripheral end face (hereinafter referred to as the "end point position").

When the swing bracket 3 is at the starting point, as shown in FIG. 3, on the straight line k extending in a direction substantially orthogonal to the tangential direction of the contact point P between the wheel 4 and the driven surface 15, the contact points P, The center of the oscillating shaft 7 and the center of the axle 8 are arranged substantially in a line.

On the other hand, as shown in FIG. 4, when the swing bracket 3 is at the end point position, the swing bracket 3 is moved clockwise about the swing shaft 7 from the above “start position” by an angle of 0 ( (In Fig. 4, it is approximately 20 °). In FIG. 3, the tangential direction at the contact point P between the wheel 4 and the rolling surface 15 is a direction that coincides with the ridge line on the surface of the rolling surface 15.

As shown in FIG. 3, the swinging bracket 3 includes an urging member 1 1 that urges the swinging bracket 3 from the end point to the start point, that is, in the counterclockwise direction in FIG. Is attached. By the urging of the urging member 11, the guide pin 10 abuts on the inner peripheral end face (start end face) of the other end in the longitudinal direction of the guide groove 9 (the lower side in FIG. 3), and the swing bracket 3 is not provided. It is located at the above-mentioned starting point position in a load state.

The biasing member 11 is a leaf spring formed of an elastic body such as panel steel that can be elastically deformed, and is mainly provided with a locking portion lla, a curved portion 11b, and a locking portion 11c. ing.

At one end of the biasing member 11, a locking portion 11 a folded back into a substantially J-shape when viewed from the side is provided, and the locking portion 11 a is attached to the swing bracket 3 near the swing shaft 7. Locked to top plate 3c. The urging member 11 extends from the locking portion 11 a to the swing shaft 7, and is curved so that the extended portion straddles at least a part of the outer periphery of the swing shaft 7. The curved portion 11b is formed.

The biasing member 11 is bent into a substantially rectangular shape in a side view at the curved portion 11b, and the tip of the biasing member 11 is bent. Extending toward the input pin 10. At the end of the extending portion, there is provided a locking portion 11 c which is folded back in a substantially annular shape when viewed from the side. The locking portion 11 c is wound around the outer periphery of the guide pin 10 and locked. . A buffer 12 having a substantially circular outer shape in a side view is fitted inside the inner periphery of the locking portion 11c.

The buffer body 12 is formed in a substantially circular shape in a side view in which the outer periphery matches the inner peripheral shape of the locking portion 11 c of the urging member 11. A substantially circular through-hole is formed in the center of the axis of the buffer 12 and is concentric with the outer periphery of the buffer 12. A guide bin 10 is inserted into the through-hole. The through hole into which the guide bin 10 is inserted is formed so as to penetrate in the axial direction of the buffer 12 (perpendicular to the plane of FIG. 3 and FIG. 4). It is slidably fitted in guide grooves 9, 9 provided in the side plates 3a, 3b of the moving bracket 3, respectively.

Such a buffer 12 is made of a material having durability and elastic restorability, for example, a resin material such as a hard polyurethane resin, and the guide pin 10 sticks inside the locking portion 11 c. Can be prevented. Moreover, since the both ends in the axial direction of the buffer 12 are fitted in the guide grooves 9, 9, direct collision or contact between the guide pin 10 and the guide groove 9 is prevented. When the guide bin 10 and the guide bin 10 are formed of a metal material, it is possible to prevent collision noise and rubbing noise between the metal materials.

In this way, by providing a buffer in one of the guide groove 9 and the guide bin 10 which are in abutting relationship with each other, it is possible to buffer such a collision and reduce the collision noise. The rubbing noise and the like caused by the sliding of are also reduced.

Returning to FIG. The biasing member 11 has an angle a between a portion extending from one locking portion 11a to the bending portion 11b and a portion extending from the bending portion 11b to the other locking portion 11c. The angle α is set to about 90 ° or less (about 45 ° in FIG. 3).

Further, the biasing member 11 reduces the angle of the curved portion 11 b by inserting the guide bin 10 into the guide groove 9 as the swing bracket 3 swings. This is to generate a restoring force to return the swing bracket 3 to the starting point position by the elastic deformation accompanied by the reduction of the degree Q !. That is, the natural restoring force of the urging member 11 becomes the urging force for urging the swing bracket 3.

Further, a portion of the urging member 11 extending from the locking portion 11a to the curved portion 11b is shorter than a portion extending from the locking portion 11c to the curved portion 11b. Therefore, in the biasing member 11 formed of the elastic body, the portion from the curved portion 11b to the locking portion 11a is unlikely to be bent and deformed. That is, the bending moment exerted on the bending portion 11b by the external force applied to the portion from the bending portion 11b to the locking portion 11a can be reduced, and the elastic member 11 can be provided with strong elasticity.

Next, a method of using the caster 1 configured as described above will be described with reference to FIGS. Here, FIG. 5 (a) is a side view of the caster 1 in a state where the swing bracket 3 is at the start position, and FIG. 5 (b) is a caster in a state where the swing bracket 3 is in the end position. It is a side view of evening 1.

According to the caster 1, the support 2 is attached via a port 5 to an object (not shown) such as a lower end of a support of a wheelchair or a lower surface of a bogie. As a result, the support 2 is attached to the object so as to be rotatable about the port 5 in the horizontal plane with respect to the central axis.

When the wheel 4 rolls on the rolling surface 15, first, the support 2 is rotated in a horizontal plane about the port 5, and the caster 1 attached to the object is rotated with the wheel 4. The direction of the support 2 can be changed by itself so that the contact point P with the moving surface 15 is located behind the bolt 5 in the traveling direction (left side in FIG. 5).

As a result, the turning direction of the wheel 4 (clockwise direction in FIG. 5) coincides with the swinging direction (clockwise direction in FIG. 5) of the swing bracket 3 from the start position to the end position. In other words, when the swing bracket 3 swings while the caster 1 is moving, the swing bracket 3 always swings rearward in the traveling direction (the left side in FIG. 1) due to the rolling of the wheels 4. Become. · After that, the object moves in the traveling direction (right side in FIG. 5) as the wheel 4 rolls. For example, the wheel 4 goes down the step on the rolling surface 15 to When 4 collides with the driven surface 15 and receives an impact force, the swing bracket 3 swings from the start position to the end position.

By the swing of the swing bracket 3, the guide pin 10 is relatively slid in the guide groove 9 from the other end in the longitudinal direction (the lower side in FIG. 1) to one end in the longitudinal direction (the upper side in FIG. 1). However, with the relative sliding of the guide pins 10, the biasing member 11 is subjected to elastic deformation accompanied by a reduction in the angle of the curved portion 11b (see FIGS. 3 and 4).

With this elastic deformation, an elastic restoring force is generated in the urging member 11, and by this elastic restoring force, a force is applied to the swing bracket 3 to push the swing shaft 7 back to the starting position with the swing shaft 7 as the swing center. . Further, the swing of the swing bracket 3 causes the axle 8 of the wheel 4 to move from the state in which the axle 8 of the wheel 4 and the contact point P of the driven surface 15 are aligned on a straight line k (see FIG. 5A). The wheel 4 is moved toward the rear in the traveling direction of the wheel 4 (leftward in FIG. 5) with respect to the support 2 while drawing an arc-shaped trajectory around the driving shaft 7.

After that, the elastic deformation of the urging member 11 proceeds, and the elastic restoring force of the urging member 11 exceeds the force for oscillating the swing bracket 3 or the guide as shown in FIG. 5 (b). When the rocking limitation by the groove 9 and the guide pin 10 is applied, the rocking bracket 3 is urged by the elastic restoring force of the urging member 11 and moves in the opposite direction with respect to the support 2. As a result, the trajectory is swung about the oscillating shaft 7 toward the start point side along an arc-shaped trajectory, and returns to the original state shown in FIG. 5 (a).

According to the caster 1 configured as described above, when the swing bracket 3 swings, the wheel 4 and its axle 8 move rearward in the traveling direction of the wheel 4 with respect to the support 2 (FIGS. 1 to 5). To the left). In this case, since the axle 8 takes an arc-shaped trajectory due to the swing of the swing bracket 3, the vertical distance from the axle 8 to the swing shaft 7 becomes shorter from the distance L to the distance (L-1ΔΥ). Become. The difference Δ Δ in the vertical distance is the amount of change in the distance from the swing shaft 7 to the contact point P between the wheel 4 and the rolling surface 15, and This corresponds to the amount of vertical movement of wheel 4 (the amount of vertical movement).

For example, if the distance L from the axle 8 to the swing shaft 7 is approximately 6 cm, and the swing bracket 3 swings approximately 20 ° from the start position to the end position, the horizontal position of the wheel 4 with respect to the support 2 The travel distance Δ Χ (= 6 · sin 20 °) is approximately 20.5 mm, whereas the vertical travel distance Δ Υ of the wheel 4 with respect to the support 2 (= 6-6 · cos 20 °) Is approximately 3.6 mm. Thus, when the wheel 4 receives an impact, the impact force can be buffered by largely moving the impact force in the horizontal direction.

Moreover, the vertical movement amount Δ Δ of the wheel 4 is greatly reduced compared to the horizontal movement amount ΔΧ, so that the vibration of the wheel 4 in the vertical direction can be reduced without using an attenuator such as a damper. It can be attenuated early. Therefore, when the wheel 4 rolls over the step of the rolling surface 15, the vertical movement of the wheel 4 with respect to the support 2 can be reduced, and the object vibrates up and down greatly while moving. Thus, the starting resistance at the start of rolling of the wheel 4 can be reduced. 'Next, a modification of the first embodiment will be described with reference to FIGS. FIG. 6 is a side view of the caster 20 according to the second embodiment, FIG. 7 is a cross-sectional view showing an internal structure of the caster 20, and FIG. FIG. 4 is a side view of the caster 20 in the case of FIG.

The caster 20 of the second embodiment includes an urging member for urging the swing bracket mainly from the end position to the start position with respect to the caster 11 of the first embodiment. It has been changed. Hereinafter, the same portions as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted, and only different portions will be described. In addition, in FIGS. 6 to 8, members having the same use and function as the members of the caster 1 of the first embodiment are given the same names, and detailed description is omitted.

As shown in FIG. 6, the wheel 4 is pivotally supported by the lower end of the swing bracket 22 via the axle 8, and the swing bracket 22 swings on the support 21 via the swing shaft 23. It is freely supported. In addition, the swing shaft 23 penetrates the swing bracket 22 and the support The center of the swinging shaft 23 is aligned with the center of the axle 8 and the contact point P on the straight line k. Have been.

The end of the guide bin 25 in the axial direction (perpendicular to the paper surface in FIG. 6) is fastened to the swing bracket 22 via an E-shaped retaining ring 26. The guide pin 25 is connected to the swing bracket. 22 and the support 21 are provided.

As shown in FIG. 7, the housing 24 is a hollow cylindrical body having an inner peripheral shape that is substantially square in cross section, and a buffer member 27 made of an elastic material such as rubber is provided on the inner peripheral portion. ing. The cushioning member 27 has an outer peripheral shape formed in a substantially square shape in cross section in conformity with the inner peripheral shape of the housing 24, and an opening having a substantially square inner peripheral shape in cross section in the center thereof. A part is formed.

The opening of the buffer member 27 is formed so as to penetrate in the axial direction of the housing 24, and the rectangular shaft portion 23 a of the swing shaft 23 is provided. The rectangular shaft portion 23 a of the oscillating shaft 23 has an outer peripheral shape having a substantially square shape in cross section that matches the inner peripheral shape of the buffer member 27. When the part 23 a rotates around the central axis, the cushioning member 27 is elastically deformed so as to be twisted in the housing 24. Due to the elastic deformation of the cushioning member 27, an urging force for pushing the swing bracket 22 to the start point position is obtained.

Further, the support 21 is provided with a guide groove 28 for slidably fitting the guide pin 25 having the buffer 12 around the outer periphery. The guide groove 28 is formed in a substantially arc-shaped long hole centered on the swing shaft 23, and is a long groove extending in the same direction as the swing direction of the swing bracket 22. The guide pin 25 is a shaft-like body having a substantially circular shape in cross section and provided in the width direction of the support 21 (perpendicular to the plane of FIG. 7). It is fitted inside.

The shock absorber 12 wrapped around the outer periphery of the guide bin 25 is formed in a cylindrical shape extending in the axial direction of the guide bin 25, and both ends in the axial direction are guide grooves 2 of the swing bracket 22. 8 are fitted. Therefore, the guide pin 25 and the guide groove 28 When the swing bracket 22 and the guide bin 25 are formed of a metal material, it is possible to prevent a collision sound and a rubbing sound between the metal materials. The guide groove 28 is a substantially arc-shaped long groove as viewed from the side as described above, and both ends in the longitudinal direction are closed.

Here, when the swing bracket 22 is swung clockwise from the starting point position shown in FIG. 7 by an angle of 0, the guide pin 25 moves along with the swing bracket 22 to one end in the longitudinal direction of the guide groove 28. (The lower side in Fig. 7) is abutted against the inner peripheral end surface (termination surface), and this abutment restricts sliding in the guide groove 9. Due to the abutment of the guide pins 25, the swing bracket 22 is restricted from swinging clockwise at the position shown in FIG.

On the other hand, when the swing bracket 22 is swung counterclockwise from the end position shown in FIG. 8, the guide pin 25 is moved to the other end of the guide groove 28 in the longitudinal direction as shown in FIG. (Upper side in Fig. 7) is abutted against the inner peripheral end surface (start end surface), and this abutment restricts sliding in the guide groove 28. Due to the abutment of the guide pins 25, the swing bracket 3 is restricted from swinging counterclockwise at the positions shown in FIGS.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. Can easily be inferred.

For example, in the second embodiment, the outer peripheral shape and the inner peripheral shape of the rectangular shaft portion 23 a of the swing shaft, the buffer member 27, and the housing 24 are formed to be substantially square in cross section. The shape and inner peripheral shape are not necessarily limited to a substantially square shape in cross section, and may be, for example, an elliptical shape or another polygonal shape. Industrial applicability

According to the CAS of the present invention, when the wheel goes down or climbs over a step, the impact force received by the wheel is such that the holding member opposes the urging force of the urging member from the starting position to the end point. The wheel is moved to the position side, and the wheel moves And buffered. At this time, the wheel is slightly moved up and down with respect to the mounting member, but the amplitude of the up and down movement is smaller than the amount of movement of the wheel backward in the traveling direction, and is significantly reduced as compared with the conventional caster. You.

Therefore, there is an effect that the large vertical vibration of the wheel can be suppressed without using an attenuator, and the vertical vibration can be quickly converged. In addition, since the amplitude associated with the up-and-down vibration of the wheel is small, when used for an object such as a wheelchair, there is an effect that the sinking of the wheel does not give a discomfort to the occupant. Further, there is an effect that the starting resistance at the start of rolling of the wheels can be reduced.

Further, the caster of the present invention does not need to use an attenuator for forcibly attenuating the vertical vibration of the wheels due to its structure, and the structure of the caster itself can be simplified accordingly. Therefore, the production cost of the caster itself can be reduced, and the caster itself can be hardly broken down.

Claims

The scope of the claims

1. A caster including a wheel that can roll on a rolling surface and a mounting member that attaches the wheel to an object,

A holding member that pivotally supports the axle of the wheel and rotatably holds the wheel, a swing shaft that pivotally supports the holding member to the mounting member,

From the starting position where the swing axis and the axle of the wheel are arranged in a direction substantially perpendicular to the tangential direction of the wheel and the rolling surface, the axle of the wheel is predetermined from the starting position about the swing axis. Limiting means for restricting the swing of the holding member within a range up to the end position at which the angular displacement has occurred;

An urging member for urging the holding member, whose swinging is restricted between the start point position and the end point position by the restricting means, toward the start point position so as to be positioned at the start point position. A caster that cushions shocks.

2. The limiting means, when the holding member is at the start point position, causes at least a part of the holding member and the mounting member to abut against each other in a swing direction toward the start point position of the holding member. When the holding member is at the end point position, at least a part of the holding member and the mounting member are brought into abutment in a swing direction toward the end point position of the holding member. Casu Yuichi relieves the shock described in paragraph 1.

3. The restricting means comprises: an engaging member provided on one of the holding member or the mounting member; and a slidably fitted engagement member, and the swing shaft is mounted on the other side of the holding member or the mounting member. A starting end face with which the engaging member abuts when the holding member is at the start point position, and the engaging member abuts when the holding member is at the end point position. And a guide groove having an end surface formed to reduce the impact according to claim 1 or 2.

4. The biasing member has one end locking portion having one end locked to one of the holding member or the mounting member in the vicinity of the swing shaft, and from the one end locking portion toward the swing shaft. A curved portion that is extended and curved so as to straddle at least a part of the outer periphery of the swing shaft, and is bent from the curved portion at an angle of about 90 ° or less with respect to the one-end locking portion. An elastic body having the other end locking portion locked to the other of the holding member or the mounting member,

When the holding member is swung from the start point side to the end point side around the swing axis, the elastic body is disposed in front of the one end locking part side via the bending part. The impact according to any one of claims 1 to 3, characterized in that the angle formed between the other end engaging portion side is reduced and an urging force is generated with the reduction. Caster to soften.

5. One end locking portion of the elastic body is locked to the holding member in the vicinity of the swing shaft,

The other end locking portion of the elastic body is wound and locked around the outer periphery of the engaging member, and the engaging member is provided as a part of the mounting member. A caster to mitigate the impact described in item 4.

6. The elastic body is characterized in that the length from the curved portion to the one-end locking portion is shorter than the length from the curved portion to the other-end locking portion. Casu Yuichi to relieve the impact described in paragraph 4 or 5.

7. The urging member includes an elastic body which is non-rotatably attached to the mounting member.

The impact according to any one of claims 1 to 3, wherein at least a part of the swing shaft is non-rotatably passed through an inner peripheral portion of the elastic body. Casters to relieve the heat.

8. A part of the swing shaft has a substantially polygonal outer peripheral shape,

The elastic body has a substantially polygonal inner peripheral shape that matches the substantially polygonal outer peripheral shape of the pivot axis. It is formed in a substantially cylindrical shape having a square outer peripheral shape,

The shock absorber according to claim 7, wherein the mounting member includes an elastic body attaching portion formed in a substantially cylindrical shape having an inner peripheral shape that matches the outer peripheral shape of the elastic body. Caster to soften.