JPH09220261A - Adjustment structure for caster angle of wheelchair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily adjust the axial direction of a caster shaft to a vertical direction even when the axial direction of a head pipe fixed to a frame is changed and to make a caster angle hardly go wrong even when a front wheelt intereferes with an obstacle or the like. SOLUTION: On the lower end of the frame 6, an insertion hole 6a whose cross section is circular capable of inserting and fixing a head pipe upper part 10a by a first clamp 9 is formed. Between bearings 14a and 14e and the fitting hole 10c of the lower end of the head pipe 10, an almost cylindrical sleeve 13 is disposed. The cross section of the fitting hole 10c is made circular, the sleeve 13 can be fitted and fixed by a second clamp 11 and the axial direction Y1 is made to cross to the axial direction Y0 of the head pipe upper part 10a. On the inner peripheral side of the sleeve 13, an assembly hole 23 to which the bearings 14a and 14e are fitted and the caster shaft 15 and the axial direction X1 are made coaxial by crossing the axial direction X0 of the outer peripheral surface of the sleeve is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel caster angle adjusting structure composed of caster wheels of a wheelchair.

[0002]

2. Description of the Related Art Conventionally, a front wheel of a wheelchair is composed of caster wheels, an axle is supported by a fork extending obliquely, and an upper portion of the fork has a caster axle (a kingpin shaft of a vehicle) extending upward. (Corresponding) is fixed,
The caster shaft is rotatably held by a head pipe connected to the front part of the frame with a bearing interposed.

The conventional head pipe is usually welded and fixed to the frame. Therefore, depending on the physique and preference of the user, for example, when attempting to lower the seat intersection, the rear part of the frame lowers, the head pipe fixed to the front part of the frame tilts backward, and the caster angle ( The angle between the axial direction of the caster shaft and the vertical direction may change from 0 ° to several °.

If the caster angle deviates from the vertical direction as described above, it prevents the front wheels from freely rotating by 360 °, which makes it difficult to change the direction of the wheelchair, which is not preferable.

Therefore, in order to adjust the caster angle in the vertical direction even if the inclination angle of the seat is to be adjusted, conventionally, the angle of the head pipe can be adjusted with respect to the frame as follows. It had a structure.

That is, the head pipe is held by a plurality of clamps, and the clamps are screwed to a mounting plate welded to the frame. Then, the structure was such that the clamp was screwed to the mounting slope.

However, in the conventional structure, even if the screw is initially screwed to a proper position, when the front wheel hits an obstacle, the position of the clamp screwed to the mounting plate is changed, and the head pipe of the head pipe is changed. The axial direction, that is, the axial direction of the caster shaft is deviated from the vertical direction, which hinders the free rotation of the front wheels by 360 °.

The present invention is to solve the above-mentioned problems, and even if the axial direction of the head pipe fixed to the frame changes, the axial direction of the caster shaft can be easily approached in the vertical direction. It is an object of the present invention to provide a caster angle adjusting structure for a wheelchair, which can be adjusted and whose caster angle is hard to come up even if the front wheels interfere with an obstacle or the like.

[0009]

In the caster angle adjusting structure according to the present invention, a caster shaft is fixed to an upper portion of a fork supporting a front wheel, and the caster shaft is fixed to a frame of a wheelchair through a bearing. Held by the head pipe
A caster angle adjusting structure for a wheelchair capable of adjusting the axial direction of the caster shaft, wherein the lower end of the frame is:
An insertion hole having a circular cross section is formed so that the upper portion of the head pipe can be inserted and fixed using the first fixing means, and a substantially cylindrical sleeve is formed between the bearing and the inner peripheral surface of the lower end of the head pipe. Is arranged so that the sleeve can be fitted and fixed to the lower end of the head pipe by using the second fixing means, and with respect to the axial direction of the portion of the head pipe inserted into the insertion hole. A fitting hole having a circular cross section intersecting the axial direction is formed, and the bearing is fitted to the inner peripheral side of the sleeve, and the outer peripheral surface of the portion of the sleeve to be inserted into the fitting hole is formed. An assembly hole that intersects the axial direction and is coaxial with the caster shaft in the axial direction,
It is characterized by being formed.

It is preferable that a flange portion is formed on the sleeve so as to project from a lower end of the head pipe, and a locking surface for rotating the sleeve is formed on the collar portion.

Further, the intersection angle between the axial direction of the assembling hole of the sleeve and the axial direction of the outer peripheral surface of the portion of the sleeve to be inserted into the fitting hole, and the axial direction of the fitting hole of the head pipe. It is desirable that the intersection angle with the axial direction of the portion of the head pipe that is inserted into the insertion hole be equal.

[0012]

According to the caster angle adjusting structure of the present invention, the caster shaft is fixed between the head pipe fixed to the frame and the caster shaft and coaxial with the caster shaft on the inner peripheral side with respect to the axial direction of the predetermined outer peripheral surface. A sleeve that intersects the axial direction of the hole is inserted, and the fitting hole that fixes the sleeve of the head pipe also intersects the axial direction of the part that is inserted and fixed in the frame of the head pipe. I am letting you.

Therefore, even if the axial direction of the frame insertion portion of the head pipe is changed in an attempt to change the seat or the like according to the physique and preference of the user, the head pipe and the head pipe are released by fixing the first and second fixing means. If the sleeve and the sleeve are respectively rotated in a predetermined direction, the insertion hole and the fitting hole have a circular cross section and can be easily rotated, and as a result, the assembly hole in the sleeve and the predetermined outer peripheral surface can be easily rotated. The caster shaft is vertically moved by adjusting the rotation angle of each of the two intersecting angles of the crossing in the axial direction and the crossing in the axial direction between the fitting hole in the head pipe and the frame insertion portion of the head pipe. Can be placed close to each other, and then each component can be fixed by the first and second fixing means.

The sleeve is fixed in the fitting hole of the head pipe by fixing the second fixing means, and the upper part of the head pipe is fixed in the insertion hole of the frame by fixing the first fixing means. Will be done. Therefore, even if the front wheel as the caster wheel interferes with an obstacle, the sleeve itself fixed in the fitting hole of the head pipe is hard to rotate, and the head pipe itself fixed in the insertion hole of the frame is also It becomes difficult to rotate, and the caster angle does not roll.

Therefore, according to the caster angle adjusting structure of the present invention, even if the axial direction of the frame insertion portion of the head pipe fixed to the frame changes, the rotational adjustment of the sleeve and the head pipe allows the axial direction of the caster shaft to be adjusted. Can be easily adjusted to approach in the vertical direction, which is convenient for seat angle adjustment to make it easier to sit, and even if the front wheels interfere with obstacles etc., the caster angle is hard to come up.

When the collar portion protruding from the lower end of the head pipe is formed on the sleeve and the locking surface for rotating the sleeve is formed on the collar portion, after the second fixing means is released from the fixing, The rotation of the sleeve can be adjusted by applying a spanner, wrench or the like to the stop surface, and the caster angle adjustment work can be easily performed.

Further, an intersecting angle between the axial direction of the assembling hole of the sleeve and the axial direction of the outer peripheral surface of the fitting hole insertion portion of the sleeve,
If the angle of intersection between the axial direction of the fitting hole of the head pipe and the axial direction of the frame insertion portion of the head pipe is equal,
The following actions and effects can be obtained.

That is, even if the axial direction of the insertion hole of the frame is arranged in the vertical direction, the axial crossing of the assembly hole and the outer peripheral surface of the fitting hole insertion portion in the sleeve, and the head. If the sleeve and the head pipe are rotated so that the fitting hole in the pipe and the frame insertion portion of the head pipe intersect with each other in the axial direction, two intersection angles can be obtained. Can be offset
The caster shaft can be arranged in the vertical direction.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

In the wheelchair C of the embodiment, as shown in FIG. 1, a frame 1 has a rear frame 4, which connects the upper horizontal frame 2, the lower horizontal frame 3, and the rear ends of the upper and lower horizontal frames 2 and 3 to the left and right, And a front frame 6 connecting the front ends of the upper and lower horizontal frames 2 and 3, respectively, and a seat frame (not shown) extending from the left and right lower horizontal frames 3 is arranged to provide a seat. ing.
Reference numeral 5 denotes an elbow pad frame which is arranged on each of the left and right sides and connects the upper horizontal frame 2 and the rear frame 4.

Axle mounting brackets 7 are fixed to the left and right rear frames 4, and large-diameter rear wheels 8 are mounted on the respective axle mounting brackets 7.

Below the front frames 6, front wheels 19 as caster wheels of small diameter are arranged.

As shown in FIGS. 1 and 2, each front wheel 19 is provided with an axle 20 which is arranged in a horizontal direction. The axle 20 has a ball bearing (not shown) arranged to rotatably support the front wheel 19. ing. And each axle 20 is a fork 1 with a bifurcated shape.
A caster shaft 15 that is supported by No. 8 and extends upward is fixed to the upper surface of the fork 18 by fixing a nut 17. Each of the caster shafts 15 has a male screw portion 15b that is screwed with the nut 17 at the lower end of the main body 15a, and has a nut 1 to be described later at the upper end of the main body 15a.
The male screw portion 15c that is screwed with the screw 6 is provided.

An annular ball bearing 14 is disposed on the outer peripheral surface of each caster shaft 15. In the case of the embodiment, as the ball bearing 14, two balls, an upper ball bearing 14a and a lower ball bearing 14e, each having an outer case 14b, 14f, an inner case 14c, 14g, and rolling elements 14d, 14h, are used. The inner case 14c, 14g is fixed to the caster shaft 15 by screwing together a sleeve 13 described later by screwing the male screw portion 15c.

A substantially cylindrical sleeve 13 is externally fitted and fixed to the outer cases 14b and 14f of the ball bearings 14a and 14e by interference fitting. The sleeve 13 is provided with an assembling hole 23 on the inner peripheral side, and the assembling hole 23 has an axial direction X1 in a fitting hole 10c of the head pipe 10 described later in the sleeve 13, as shown in FIGS. Body 1 to be inserted
The outer peripheral surface of 3a is formed so as to intersect with the axial direction X0 so as to have a crossing angle α of 3 °. In the case of the embodiment, the assembly hole 23 is composed of a large-diameter upper hole 23a, a small-diameter intermediate hole 23b, and a large-diameter lower hole 23c in this order from above.
Ball bearings 14a and 14e are provided in the upper hole 23a and the lower hole 23c.
The outer cases 14b and 14f are fitted and fixed.
Then, the assembly hole 23 is arranged coaxially with the caster shaft 15 via the ball bearings 14a and 14e. Further, a hexagonal plate-shaped collar portion 13b is formed at the lower end of the sleeve 13. In addition, in the case of the embodiment, the six flat surfaces of the outer peripheral surface of the collar portion 13b serve as locking surfaces 13c used when the sleeve 13 is rotated.

On the other hand, at the lower ends of the left and right front frames 6, as shown in FIGS. 1 and 2, insertion holes 6a each having a circular cross section are formed.
The upper portion (small diameter portion) 10a of the head pipe 10 is inserted into the insertion hole 6a. Also, the insertion hole 6a
A first clamp 9 is provided on the outer peripheral side as a first fixing means capable of fixing the head pipe upper portion 10a by reducing the diameter of the insertion hole 6a during tightening. The first clamp 9 is composed of a main body 9a having a substantially U-shaped cross section, and a screw 9b screwed onto the main body 9a and reducing the inner peripheral surface of the main body 9a when tightened. A split groove 6b is provided on the peripheral edge of the insertion hole 6a so that the diameter of the insertion hole 6a can be easily reduced when the screw 9b is tightened.

As shown in FIGS. 1, 2, 5, and 6, the head pipe 10 is composed of a cylindrical small-diameter portion 10a on the upper side and a large-diameter cylindrical portion 10b on the lower side. Part 10
A fitting hole 10c having a circular cross section for fitting the sleeve 13 is formed on the inner peripheral side of b. Then, a split groove 10d is formed around the fitting hole 10c so that the fitting hole 10c can be reduced in diameter and the sleeve 13 can be easily fixed when tightened by the second clamp 11 as the second fixing means. Has been done. Further, a concave groove 10e is formed on the outer peripheral surface of the large diameter portion 10b so that the second clamp 11 can be easily arranged.

The fitting hole 10c has an axial direction Y1.
Are bored so as to intersect with the axial direction Y0 of the outer peripheral surface of the small diameter portion 10a so as to have a crossing angle β of 3 °.

The second clamp 11 is screwed onto the main body 11a having a substantially U-shaped cross section, and the main body 11a is screwed into the main body 11a.
and a screw 11b for reducing the inner peripheral surface of a. In addition, the second clamp 11 is formed with a screw hole (not shown) for fixing the step 12 arranged at the lower front portion of the wheelchair C.

In the wheelchair C of this embodiment, when the seat angle is adjusted, the seat angle is adjusted by the length of the small diameter portion 10a of the head pipe to be inserted into the insertion hole 6a of the front frame 6, or the rear wheel. The mounting position of the rear frame 4 of the axle mounting bracket 7 supporting 8 is moved up and down for adjustment.

At that time, the insertion holes 6a of the left and right front frames 6 are formed.
Along with the axial direction Y0 of each head pipe small diameter portion 10a,
When tilted forward by 6 °, the left and right first clamps 9 are loosened as shown in FIG.
0 is rotated to incline the axial direction Y1 of the fitting hole 10c rearward from the axial direction Y0 of the small diameter portion 10a of the head pipe by 3 °, and then the left and right first clamps 9 are tightened. In addition, the left and right second clamps 11 are loosened, and a spanner or the like is fitted to the locking surfaces 13c, 13c of the collar portion 13b that are parallel to each other to rotate the sleeve 13 so that the axial direction X1 of the assembling hole 23 is in the sleeve body. The second clamp 11 is tightened by inclining it backward by 3 ° from the axial direction X0 of 13a.

With this adjustment, since the axial direction V of the left and right caster shafts 15 becomes the vertical direction, the left and right front wheels 1
No. 9 can rotate 360 degrees around the caster shaft 15 without any hindrance, and does not hinder the turning of the wheelchair C.

By reversing the above operation, it is possible to deal with the case where the axial direction Y0 of each head pipe small-diameter portion 10a together with the insertion holes 6a of the left and right front frames 6 is inclined backward by 6 °.

Also, by adjusting the seat, the small diameter portions 10a of the head pipes are inserted together with the insertion holes 6a of the left and right front frames 6.
When the axial direction Y0 of is the vertical direction, the left and right first and second clamps 9 and 11 are unfastened and fastened, and the left and right head pipes 10 and the sleeve 13 are rotated, As shown in FIG. 8, the axial direction Y of each fitting hole 10c
1 is inclined 3 ° rearward from the axial direction Y0 of the head pipe small diameter portion 10a, and the axial direction X1 of each assembling hole 23 is set to the sleeve 1
By tilting 3 ° forward from the axial direction X0 of 3, the axial direction V of the left and right caster shafts 15 can be made vertical. In this case, of course, contrary to the above, the axial direction Y1 of each fitting hole 10c is inclined forward by 3 ° from the axial direction Y0 of the head pipe small-diameter portion 10a, and the axial direction X1 of each assembling hole 23 of the sleeve 13 is changed. You may incline 3 degrees backward from the axial direction X0.

By adjusting the seat, the small diameter portions 10 of the head pipes 6 are inserted together with the insertion holes 6a of the left and right front frames 6.
When the axial direction Y0 of a is tilted forward or backward by less than 6 ° from the vertical direction, the first and second left and right
The clamps 9 and 11 are released and tightened, the left and right head pipes 10 and the sleeve 13 are rotated, and the axial direction Y1 of each fitting hole 10c is rearward or forward of the axial direction Y0 of the head pipe small diameter portion 10a. When the axial direction X1 of each assembling hole 23 is inclined forward or rearward of the axial direction X0 of the sleeve 13 by a predetermined angle, the axial direction V of the left and right caster shafts 15 can be made vertical. it can.
At that time, the two sleeves 13 and the head pipe 1 where the axial directions X0 and X1 and the axial directions Y0 and Y1 intersect each other
Since 0 is used, if the rotation adjustment of the sleeve 13 and the head pipe 10 is appropriately performed, the head pipe 10
If the axial direction Y0 of is within ± 6 ° from the vertical direction,
The axial direction V of the caster shaft 15 can be arranged closer to the vertical direction.

Therefore, in the adjusting structure of the embodiment, the head pipe upper portion (small diameter portion) 1 fixed to the front frame 6
Even if the axial direction Y0 of 0a changes, the axial direction V of the caster shaft 15 is adjusted by the rotation adjustment of the sleeve 13 and the head pipe 10.
The seat can be adjusted in the vertical direction, and the angle of the seat can be conveniently adjusted to make it easier to sit. Further, since this angle adjustment can be performed steplessly without replacing the parts, the angle adjustment of the seat becomes more convenient.

Further, the sleeve 13 is the head pipe 1.
The second clamp 11 capable of reducing the diameter of the fitting hole 10c at the lower end of 0.
By tightening the, the fitting hole 1 of the head pipe 10
0c, and the upper portion (small diameter portion) 10a of the head pipe 10 is inserted into the insertion hole 6a of the front frame 6 by tightening the first clamp 9 capable of reducing the insertion hole 6a of the front frame 6. It will be fixed. for that reason,
Even if the front wheels 19 as caster wheels interfere with obstacles,
The sleeve 13 itself fixed in the fitting hole 10c of the head pipe 10 is hard to rotate, and the head pipe 10 itself fixed in the insertion hole 6a of the front frame 6 is also hard to rotate, and the caster angle comes. I don't know.

Furthermore, in the embodiment, the sleeve 13
Since the flange portion 13b protruding from the lower end of the head pipe 10 is formed on the head pipe 10 and the locking surface 13c for rotating the sleeve is formed on the flange portion 13b, the second clamp 11 is unlocked and then locked. It is possible to adjust the rotation of the sleeve 13 by applying a spanner / wrench or the like to the surface 13c, and the caster angle adjustment work can be performed easily.

Further, as in the embodiment, the axial direction X1 of the assembling hole 23 of the sleeve 13 and the sleeve body 13a.
Angle α of the outer peripheral surface of the head pipe 1 with the axial direction X0
No. 0 fitting hole 10c axial direction Y1 and head pipe small diameter portion 1
If the intersection angle β of 0a with the axial direction Y0 is made equal,
Axial direction of insertion hole 6a of front frame 6 (matches Y0)
Is arranged in the vertical direction, the axial direction X1.
For example, by arranging Y1 in the opposite direction in the front-back direction, caster shaft 1
Since the axial direction V of 5 can be arranged in the vertical direction, the accuracy of arranging the caster shaft 15 in the vertical direction can be improved.

In the embodiment, the crossing angle α in the axial directions X0 and X1 and the crossing angle β in the axial directions Y0 and Y1 are set to 3 °, but these crossing angles α and β are shown. Is 3
The angle is not limited to °, and may be greater than 3 ° or less than 3 °.

Further, in the embodiment, the clamps 9 and 11 are exemplified as the first and second fixing means, but the fixing means may be a screw means, for example, the insertion hole 6a of the front frame 6 may be provided at the periphery thereof. Provide a screw hole so as to be orthogonal to 6a,
A screw screwed into the screw hole is brought into contact with the outer peripheral surface of the small diameter portion 10a of the head pipe 10 to fix the head pipe 10 in the front frame insertion hole 6a, or similarly, to fit the large diameter portion 10b of the head pipe. A screw hole is provided so as to be orthogonal to the fitting hole 10c, and a screw screwed into the screw hole is inserted into the sleeve body 13
Alternatively, the sleeve 13 may be fixed in the fitting hole 10c by contacting the sleeve 13a.

[Brief description of drawings]

FIG. 1 is a side view of a wheelchair according to an embodiment of the present invention.

FIG. 2 is an exploded side view near the caster shaft of the same embodiment.

FIG. 3 is a side view of the sleeve of the same embodiment.

FIG. 4 is a bottom view of the sleeve, as seen from the IV direction in FIG. 3.

FIG. 5 is a side view of the head pipe of the same embodiment.

FIG. 6 is a bottom view of the same head pipe as seen from the VI direction in FIG.

FIG. 7 is a side view showing a state in which the caster angle of the embodiment is adjusted.

FIG. 8 is a side view showing a state where the caster angle of the embodiment is further adjusted.

[Explanation of symbols]

 6 ... Front frame, 6a ... Insertion hole, 9 ... (First fixing means) First clamp, 10 ... Head pipe, 10a ... (Insertion hole insertion site) Small diameter portion, 10c ... Fitting hole, 11 ... (Second fixing) Means) Second clamp, 13 ... Sleeve, 13a ... (Fitting hole insertion portion) body, 14 ... Bearing, 15 ... Castor shaft, 18 ... Fork, 19 ... Front wheel, 23 ... Assembly hole, X0 ... (Sleeve outer peripheral surface) ) Axial direction, X1 ... (Assembling hole) axial direction, Y0 ... (Head pipe upper part) axial direction, Y1 ... (Fitting hole) axial direction, V ... (Caster shaft) axial direction, C ... Wheelchair.

Claims (3)

[Claims] 1. A caster shaft is fixed to an upper portion of a fork supporting a front wheel, and the caster shaft is held by a head pipe fixed to a frame of a wheelchair via a bearing,
A structure for adjusting a caster angle of a wheelchair capable of adjusting an axial direction of the caster shaft, the structure having a circular cross section capable of inserting and fixing an upper portion of the head pipe at a lower end of the frame by using a first fixing means. An insertion hole is formed, and between the bearing and the inner peripheral surface of the lower end of the head pipe,
A substantially cylindrical sleeve is provided, and the sleeve can be fitted and fixed to the lower end of the head pipe by using a second fixing means, and a portion of the head pipe to be inserted into the insertion hole is formed. A fitting hole having a circular cross section that intersects the axial direction with respect to the axial direction is formed, and the bearing is fitted to the inner peripheral side of the sleeve, and
A wheelchair characterized in that an assembly hole is formed so as to intersect with the axial direction of the outer peripheral surface of the portion of the sleeve inserted into the fitting hole, and the caster shaft is coaxial with the axial direction. Adjustable caster angle. 2. The sleeve is formed with a collar portion projecting from a lower end of the head pipe, and the collar portion is formed with a locking surface for rotating the sleeve. Wheelchair caster angle adjustment structure. 3. An intersection angle between an axial direction of an assembling hole of the sleeve and an axial direction of an outer peripheral surface of a portion of the sleeve to be inserted into the fitting hole, and an axial direction of the fitting hole of the head pipe. The caster angle adjusting structure for a wheelchair according to claim 1 or 2, wherein a crossing angle of a portion of the head pipe to be inserted into the insertion hole and an axial direction is equal to each other.