JP7199706B2 - caster structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caster structure having a swivel function, and more particularly to a caster structure that allows the casters to be oriented in a specific direction even when a moving object including casters is lifted. It is.

Casters are commonly provided at the lower end of moveable tows, carts, chairs, and the like. This caster has a revolving part that revolves about a vertical axis and a tire that rotates about a horizontal axis. It is positioned so that it can follow the turning with respect to the traveling direction.

By the way, when moving a moving body having such casters, there are cases where the entire moving body is lifted and moved.

However, when such a moving body as a whole is lifted, each caster may remain oriented in the direction at which it was lifted, or may be oriented in any direction due to vibration or the like. Therefore, when the robot moves in a different direction after it touches the ground next time, the casters pointing in a direction different from the traveling direction will put a burden on the swivel part and the like.

On the other hand, Patent Literature 1 proposes a structure in which the tires can be oriented in a specific direction when only the tires are lifted from the floor without lifting the moving body.

The structure described in Patent Document 1 is such that when moving a desk for a meeting, the casters are grounded on the floor so that the desk can be moved. When the tire is rotated 90 degrees from the fixed leg, the strut provided inside the leg is lowered to move the tire so as to protrude below the fixed leg. Also, when using this desk in an installed state, by rotating the top plate in a horizontal plane, the tire is moved above the fixed leg together with the support provided inside the leg, and the tire is moved above the fixed leg. The caster can be oriented in a specific direction along a guide surface provided in the .

JP-A-2005-96713

However, the structure of Patent Document 1 has the following problems.

That is, in the structure shown in Patent Document 1, there is a possibility that the casters may face various directions when the whole desk is lifted in order to get over a step while the tires are in contact with the floor and moved. There is For this reason, when the robot is moved on the ground next time, since the casters are in a free state, there is a problem in that a load is applied to the rotating shafts of the casters facing various directions.

In addition, when such a structure is used, for example, as a caster structure for a large towing vehicle, it is necessary to raise and lower heavy tires. Doing so may cause malfunction.

Furthermore, when such casters are installed in multiple places, for example, if the running surface has unevenness such as farmland or stone pavement, the unevenness causes the tires to face in different directions, making it difficult to travel. It becomes unstable.

Therefore, the present invention has been made by focusing on the above problems, and even when the entire moving body having casters is lifted or when moving on an uneven running surface, the direction of the casters can be set in a specific direction. It is an object to provide a caster structure that is aimed.

That is, in order to solve the above problems, the present invention provides a rotating shaft provided in a vertical direction with respect to a main body, and a vertical distance between the main body and the main body at a position away from the rotating shaft in the horizontal direction. A caster structure provided on the left and right sides of the main body, the caster comprising an axle that is provided so as to be rotatable with respect to the rotation axis, and a tire that is attached to the axle, wherein the tire is lifted from the ground, the tires of the casters provided on the left and right sides are biased to align in a specific direction with the distance between the axle and the main body set to the constant distance is provided .

With this configuration, even when the entire main body of the moving body is lifted, the tires can be oriented in the characteristic direction. Also, it is possible to eliminate the burden on the turning shaft and the like. Further, even when moving on a running surface having irregularities, the direction of the casters can be urged in the characteristic direction to some extent to make the vehicle run, so that the running can be stabilized.

Further, in such an invention, a connecting rod is provided which is connected to the casters provided on the left and right sides to align the angles of the left and right tires, and the connecting rod is provided with the biasing means.

With this configuration, when the main body is lifted, the left and right tires can be oriented in a specific direction at the same time by one biasing means provided on the connecting rod.

Furthermore, a support rod that supports the left and right casters and a connecting rod that is provided at a position apart from the support rod and that aligns the angles of the tires provided on the left and right are provided, and the biasing means is attached to the support rod. On the other hand, an elastic body is provided to return the lateral position of the connecting rod to the neutral position.

With this configuration, a link mechanism can be formed by the support rods, the connecting rods, and the like, and the link mechanism can change the angle between the inner ring and the outer ring when the main body is turned left and right. By returning the link mechanism to the neutral state, the left and right tires can be oriented straight ahead.

Further, the biasing means includes a pair of rotatable left and right levers attached between the support rod and the connecting rod, and an elastic body attached between the left and right levers. .

With this structure, the left and right levers can be attracted to each other by the elastic body, and the connecting rod can be returned to the neutral position so that the left and right tires can be oriented straight ahead. At this time, by providing an elastic body between the left and right levers, it is possible to equalize the tensile force in the left and right direction, thereby eliminating the possibility that only one tire is strongly pulled.

Further, a restricting member is provided to restrict the rotation of the left and right levers so that the levers do not rotate from the center toward the other lever.

With this configuration, the regulating member prevents the left and right levers from rotating in opposite directions from the neutral position, and the elastic body provided between the left and right levers returns the connecting rod to the neutral position. You can now align the tires in the straight-ahead direction.

According to the present invention, the turning shaft is provided in the vertical direction with respect to the main body, and the turning shaft is provided so that the vertical distance from the main body is constant at a position away from the turning shaft in the horizontal direction. In a caster structure in which casters are provided on the left and right sides of the main body, the casters are provided with an axle that is rotatable about the axle and a tire that is attached to the axle, when the tire is released from the ground. Since the wheels of the casters provided on the left and right sides are provided with biasing means for biasing the tires so as to align them in a specific direction with the distance between the axle and the main body set to the constant distance , Next, when the robot is grounded and moved in a different direction, it is possible to eliminate the load on the turning shaft and the like. Further, even when moving on a running surface having irregularities, the direction of the casters can be urged in the characteristic direction to some extent to make the vehicle run, so that the running can be stabilized.

The figure which shows the caster structure which shows one embodiment of this invention. An exploded perspective view of a caster in the same form A diagram showing the state of the ratchet part and the axle when moving forward in the same configuration A diagram showing the state of the ratchet part and the axle when moving backward in the same configuration. A diagram showing the left turning state and the state of the urging means in the same configuration. A diagram showing the right turning state and the state of the biasing means in the same configuration. The figure which shows the effect|action of the state which provided the different contact part in the same form.

An embodiment of the present invention will be described below with reference to the drawings.

A mobile object having caster structure 1 in this embodiment will be described by taking, for example, a lap machine connected to the rear part of a tractor as an example.

As shown in FIG. 1, the caster structure 1 of this embodiment has casters 2 on the left and right sides of a main body 10. When moving forward, the traction force from the tractor in front is used to move the tires 20 behind the turning shaft 33. When moving backward, the tire 20 is moved forward so as to follow the turning shaft 33 without being reversed 180 degrees around the vertical axis. Characteristically, the left and right tires 20 are connected by using a support rod 21 and a connecting rod 8 so as to form a link mechanism, so that the tires 20 can be oriented in the turning direction, and the main body can be moved by the tractor. When the tire 20 is lifted as a whole, the connecting rod 8 is returned to the neutral position by the biasing means 9 provided between the support rod 21 and the connecting rod 8 so that the tire 20 can be oriented straight ahead. It is.

First, as shown in FIG. 2, the left and right casters 2 have a revolving portion 3 having a revolving shaft 33 around a vertical axis, and an axle 55 with respect to the revolving shaft 33 to move in the front-rear direction with respect to the support rod 21. It is configured to include an axle moving unit 4 and the like. By using such an axle moving portion 4, the tire 20 is configured to follow the turning shaft 33 without being reversed 180 degrees around the vertical axis.

The swivel portion 3 of the caster 2 is provided on both end sides of a support rod 21 attached to the main body 10, and is centered on an upper bearing portion 31 and a lower bearing portion 32 provided so as to vertically face each other. An insertion hole 35 is provided, into which the turning shaft 33 is inserted with a certain gap from the vertical direction. A male screw portion 34 is formed at the tip portion of the turning shaft 33 inserted into the shaft insertion hole 35 , and is inserted into upper and lower screw holes 42 provided in the center of the axle guide 41 constituting the axle moving portion 4 . It is designed to be fixed by By inserting and fixing the turning shaft 33 into the screw hole 42 of the axle guide 41 in this way, the axle moving part 4 can be rotated around the vertical axis with the center of the turning shaft 33 inserted into the shaft insertion hole 35 as the axis. It is designed to rotate.

On the other hand, the axle moving part 4 attached to the turning part 3 uses the rotational force of the tire 20 to move the axle 55 in the longitudinal direction of the turning shaft 33. An axle guide 41 having a guide surface 43 , an axle support member 5 configured to be slidable in the front-rear direction along the axle guide 41 , and an axle 55 of the axle support member 5 along with the rotational force of the tire 20 . It is configured to have a ratchet portion 6 and the like for moving in the front-rear direction.

Among them, the axle guide 41 is provided by forming a guide surface 43 parallel to the side surface of the tire 20 and parallel grooves 44 facing the upper and lower sides thereof. A guide plate 51 of the axle support member 5 is slid forward and backward along the groove 44 and the guide surface 43 .

A pin 52 projecting vertically is provided at both front and rear ends of the guide plate 51 so as to enable smooth movement along the groove 44 of the axle guide 41. A bearing 53 is provided at the tip of the pin 52. Friction inside the groove 44 is reduced by attaching such as.

Further, the guide surface 43 is provided with an elongated hole 45 extending in the front-rear direction. The elongated hole 45 is used to set the distance by which the axle guide 41 slides in the longitudinal direction when the axle 55 is moved longitudinally with respect to the turning shaft 33 . , and abutted on the inside of the elongated hole 45 . As a result, the axle 55 can move within the range of the elongated hole 45, and the axle 55 is positioned behind the pivot shaft 33 to enable pivoting during forward movement. Positioning in front of the shaft 33 enables turning when traveling in reverse.

The ratchet portion 6 is forcibly moving the axle 55 in the longitudinal direction along the elongated hole 45 , and uses the rotational force of the tire 20 to move the axle 55 in the longitudinal direction of the turning shaft 33 . It is configured to allow As shown in FIGS. 2 to 4, the ratchet portion 6 includes a pair of front and rear rotatable claw portions 61 having their tip portions 62 (see FIGS. 3 and 4) opposed to the upper surface of the axle guide 41. and a rotary plate 7 having a protrusion capable of coming into contact with the distal end portion 62 of the claw portion 61 . The claws 61 are adapted to vertically move the respective tip portions 62 around a fulcrum 63 provided on the upper surface of the axle guide 41 , while the rotary plate 7 rotates integrally with the tire 20 . It has become. A plurality of projections 71 are provided on the surface of the rotating plate 7 concentrically. By advancing the tire 20, the rotating plate 7 is rotated in that direction as shown in FIG. The projection 71 of the rotary plate 7 is brought into contact with the tip 62 of the claw 61 on the front side (upper view in FIG. 3). At this time, the projection 71 abuts against the distal end portion 62 of the pawl portion 61, thereby restricting the movement of the rotating plate 7, and as shown in the lower diagram of FIG. move to escape. As a result, the axle 55 moves rearward beyond the turning shaft 33 . At this position, the projection 71 of the rotary plate 7 touches the lower surface 64 of the rear claw portion 61 so as to stroke it, so that the tire 20 can be rotated continuously. Conversely, when the main body 10 is moved backward from this state, the tire 20 rotates in the opposite direction as shown in the upper diagram of FIG. Then, the projection 71 provided on the rotating plate 7 hits the tip 62 of the claw 61 on the rear side, and the axle 55 moves forward along the long hole 45 so as to release the rotational force (lower figure in FIG. 4). . Then, while the axle 55 is moved to the front side of the long hole 45, the projection 71 is brought into contact with the lower surface 64 of the front claw portion 61 so as to stroke, and the rotation of the tire 20 is allowed only in front of the long hole 45. be done. As a result, the axle 55 can be positioned behind the turning shaft 33 to allow turning when moving forward, and can be allowed to turn by positioning the axle 55 in front of the turning shaft 33 when moving backward.

By moving the axle 55 back and forth in this way, it becomes unnecessary to invert the tire 20 by 180 degrees around the vertical axis, and the directionality immediately after the backward movement can be stabilized. The left and right casters 2 may face different directions. Therefore, as shown in FIG. 1, the left and right axle moving parts 4 are connected by a connecting rod 8 via a hinge 81 so that the directions of the tires 20 of the left and right casters 2 can be aligned.

The connecting rod 8 is attached to the left and right axle guides 41 via hinges 81, as shown in FIG. At this time, the connecting rod 8 is provided parallel to the front side of the support rod 21, and the left and right turning shafts 33 and the left and right hinges 81 form a link mechanism. The distance between the left and right hinges 81 is shorter than the distance between the left and right turning shafts 33, so that the left and right turning shafts 33 and the hinges 81 form a trapezoidal link.

In such a configuration, in this embodiment, when the main body 10 is lifted and moved using a tractor, the biasing means 9 is provided for directing the right and left tires 20 in the straight forward direction.

This biasing means 9 may be of any method as long as it allows the tires 20 to be oriented straight when the main body 10 is lifted. In addition, a pair of left and right levers 92 are rotatably provided at the center of the support rod 21, and a protrusion 82 is provided at the center of the connecting rod 8 so that the contact portion 93 of the lever 92 is brought into contact with the protrusion 82. It consists of This lever 92 is attached to a rotation shaft 91 provided on the support rod 21 so as to be rotatable about a vertical axis. I try to match. Further, the support rod 21 is provided with a stopper 95 that prevents the left and right levers 92 from rotating in opposite directions. 6), the lever 92 on one side is brought into contact with a stopper 95 and the lever 92 on the opposite side is pulled by a spring 94. As shown in FIG. When the projection 82 is returned to the neutral position by the spring 94 in this way, the left and right tires 20 are directed straight ahead. Since the frictional force due to the contact of the tire 20 becomes greater than the force, the orientation of the tire 20 during running is not affected.

A contact portion 93 of the lever 92 that contacts the protrusion 82 is configured to have a curved shape protruding toward the protrusion 82 . As a result, even when the lever 92 is rotated, the force of the spring 94 from the lever 92 can be directed along the connecting rod 8 . That is, in the case where the lever 92 is configured linearly, as shown in the right diagram of FIG. and the return force cannot be directed in the direction of the connecting rod 8. Therefore, here, the contact portion 93 is curved in an arc shape so that the return force of the spring 94 can be directed toward the connecting rod 8 as shown in the left diagram of FIG.

Next, the operation when using the caster structure 1 configured as described above with the main body 10 will be described.

First, when the main body 10 is moved forward using a tractor, the tire 20 rotates in the direction in which it is pulled by the tractor. Then, as shown in the upper diagram of FIG. 3, the rotating plate 7 rotates with the rotation of the tire 20, and the protrusion 71 provided on the surface of the rotating plate 7 hits the tip portion 62 of the front claw portion 61. As shown in FIG. Then, the axle 55 is moved rearward so that the rotary plate 7 escapes therefrom. As a result, the axle 55 is positioned behind the turning shaft 33 (lower diagram in FIG. 3), and the tire 20 can be made to follow the traction direction when moving forward.

At this time, when the main body 10 tries to turn in the direction shown in FIG. 5, the tire 20 turns around the turning shaft 33 following the pulling direction. At this time, since the pivot shaft 33 of the support rod 21 and the hinge 81 of the connecting rod 8 constitute a trapezoidal link, the angle of the tire 20 on the inner side in the turning direction can be increased, and the tire 20 on the outer side in the turning direction can be rotated. angle can be reduced. As a result, the axial center of the tire 20 can be focused on the turning center side, and the generation of thrust load can be prevented.

On the other hand, when changing the direction from the forward movement to the backward movement, the main body 10 is reversed by the tractor. As a result, the tire 20 rotates in the backward direction, and the rotating plate 7 also rotates in the backward direction. Then, as shown in FIG. 4, the projection 71 of the rotary plate 7 hits the tip 62 of the claw 61 on the rear side, and the rotary plate 7 moves forward so as to escape from it. Then, the tire 20 is rotated with the axle 55 positioned in front of the turning shaft 33 . As a result, by switching the axle 55 in the longitudinal direction with respect to the turning shaft 33, it is possible to secure directional stability when changing direction to forward/reverse and running stability when running on uneven ground. become able to.

When the main body 10 is turned in this manner during backward movement, the trapezoidal link is used to increase the angle of the tire 20 on the inner side in the turning direction and to decrease the angle of the tire 20 on the outer side in the turning direction. As a result, the axial center of the tire 20 comes to focus on the turning center side, so that the generation of thrust load can be prevented.

When the main body 10 is lifted and moved using a tractor, the main body 10 is lifted as it is by operating the lower link of the tractor.

Then, the tire 20 separates from the running surface, and the frictional force from the ground applied to the tire 20 disappears.

At this time, when the tire 20 is turned leftward as shown in FIG. 93 comes to be pressed by the protrusion 82 . On the other hand, the left lever 92 abuts against the stopper 95 and is positioned in a neutral state, from which the right lever 92 is pulled by the spring 94 . Then, the connecting rod 8 tries to return to the neutral position. At this time, since the contact portion 93 of the right lever 92 has a curved shape, the return force of the lever 92 is directed in the axial direction of the connecting rod 8, and the connecting rod 8 is returned to the neutral position with a light force. be able to

On the other hand, when the tire 20 turns to the right as shown in FIG. is pushed by the protrusion 82. On the other hand, the right lever 92 abuts against the stopper 95 and is positioned in a neutral state, from which the left lever 92 is pulled by the spring 94 . Then, the connecting rod 8 tries to return to the neutral position. At this time, since the contact portion 93 of the left lever 92 has a curved shape, the return force of the lever 92 is directed in the axial direction of the connecting rod 8, and the connecting rod 8 is returned to the neutral position with a light force. be able to

When the lever 92 returns to the neutral position in this way, the left and right tires 20 connected to the connecting rod 8 are oriented straight ahead.

As described above, according to the above-described embodiment, the pivot 33 provided in the vertical direction with respect to the main body 10 of the lap machine, and the vertical direction of the main body 10 at a position away from the pivot 33 in the horizontal direction. A caster 2 provided with a constant distance and provided with an axle 55 rotatable with respect to the rotation shaft 33 and a tire 20 attached to the axle 55 is mounted on the left and right sides of the main body 10. In the caster structure 1 provided in the above, when the tires 20 are separated from the ground, the tires 20 of the casters 2 provided on the left and right are set so that the distance between the axle 55 and the main body 10 is the constant distance Since the urging means 9 is provided to apply a force so as to align them in a specific direction, the load on the turning shaft 33 or the like can be eliminated when they are next grounded and moved in a different direction. will be able to Further, even when moving on a running surface having irregularities such as farmland, the direction of the casters 2 can be made to run straight to some extent, so that the running can be stabilized.

It should be noted that the present invention is not limited to the above embodiments, and can be implemented in various modes.

For example, in the above embodiment, agricultural machines such as a lap machine have been described as an example of a moving object, but the present invention can also be applied to objects that can move on a running surface, such as carts, desks, desks, and the like. can.

In the above-described embodiment, the caster structure 1 is configured so that the axle 55 of the tire 20 can be moved in the front-rear direction with respect to the support rod 21 to change the position of the axle 55 between forward and backward movement. Instead, it can also be applied to a structure in which the tire 20 is turned 180 degrees around the vertical axis with respect to the turning shaft 33 . However, when the present invention is applied to such a caster 2, if the connecting rod 8 or the like is provided, the tire 20 cannot be turned 180 degrees. Therefore, without providing the connecting rod 8, a spring or the like may be attached so that the turning shaft 33 can always be oriented in the straight direction so that the tire 20 can be oriented in the straight direction.

1: caster structure 2: caster (20 tires, 21 support rods)
3... Turning portion (31 upper bearing portion, 32 lower bearing portion, 33 turning shaft, 34 male screw portion)
4 Axle moving part (41 axle guide, 42 screw hole, 43 guide surface, 44 groove, 45 long hole)
5 Axle support member (51 guide plate, 52 pin, 53 bearing, 54 bolt, 55 axle)
6 Ratchet part (61 pawl part, 62 tip part, 63 fulcrum, 64 lower surface)
7 Rotating plate (71 projections)
8 ... connecting rod (81 hinges, 82 protrusions)
9: biasing means (91 rotation shaft, 92 lever, 93 contact portion, 94 spring, 95 stopper)
10... vehicle body

Claims (5)

a turning shaft provided in a vertical direction with respect to the main body;
an axle provided so that a vertical distance from the main body is constant at a position away from the pivot shaft in the horizontal direction, and rotatable with respect to the pivot shaft;
a tire mounted on the axle;
In a caster structure in which casters are provided on the left and right sides of the main body,
When the tire is lifted from the ground, a force is applied to align the tires of the casters provided on the left and right sides in a specific direction with the distance between the axle and the main body set to the constant distance. A caster structure characterized in that a force means is provided . A connecting rod is provided that is connected to the casters provided on the left and right and aligns the angles of the left and right tires,
2. A caster structure according to claim 1, wherein said connecting rod is provided with said biasing means. a support rod that supports the left and right casters ;
a connecting rod provided at a position apart from the support rod and arranged to align the angles of the tires provided on the left and right;
2. A caster structure according to claim 1, wherein said urging means has an elastic body for returning the lateral position of said connecting rod to said neutral position with respect to said supporting rod. The urging means comprises a pair of rotatable left and right levers attached between the support rod and the connecting rod, and an elastic body attached between the left and right levers. A caster structure according to claim 3. 5. The caster structure according to claim 4, further comprising a restricting member for restricting rotation of said left and right levers so that said levers do not rotate from the center toward the other lever.

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