JP2018062259A - Bicycle for training to bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bicycle for training to bicycle, which enables easy and speedy attachment/detachment of a bracket unit pivotally supporting a pedal crank and which excels in strength and durability.SOLUTION: A bicycle for training to bicycle, in which a coupling part 31 projecting from a bracket unit 30 is attachable to or detachable from a cylindrical part 21 extending downward from a body frame of a vehicle body, comprises: a vertically long slit 22 formed at the lower end of the cylindrical part 21; a body-side through-hole 23 formed above the slit 22; a projection 32 formed on the coupling part 31 and engaged with the slit 22 so as to be vertically disposed in contact with the inside faces of the slit; and a bracket-unit-side through hole 33 formed in the coupling part 31 in a position where this through-hole coincides with the body-side through-hole 23 when the slit 22 and the projection 32 are engaged. The coupling part 31 is fixed to the cylindrical part 21 by means of a bolt 40 and a nut 41 inserted into both the through-holes 23, 33.SELECTED DRAWING: Figure 1

Description

  The present invention is excellent in the strength, stability and durability of the connecting portion between the bracket unit for supporting the pedal crank and the main body frame of the vehicle body, and easily and quickly attach and detach the bracket unit and the main body frame. It relates to a bicycle for running practice.

  Conventionally, a bracket unit (pedal unit) equipped with a pedal and pedal crank can be removed from the body frame of the vehicle body as a driving practice bicycle suitable for practice for children to be able to ride on the bicycle. Some have been proposed (Patent Documents 1, 2, and 3).

In the bicycle for running practice described in Patent Document 1, a cylindrical connecting portion (contained portion) that protrudes from the pedal unit extends from the main body frame of the vehicle body to the cylindrical portion (connection). A vertical slit formed at the lower end of the cylindrical portion so as to extend along the longitudinal direction, and at a position 90 degrees lateral to the slit. A body-side through hole formed in the cylindrical portion is provided.
On the other hand, the connecting portion of the pedal unit has a columnar protrusion fitted into the slit, and a position of the pedal unit at a position coincident with the through hole on the main body side in a state where the slit and the protrusion are engaged. A pedal unit side through hole formed in the connecting portion is provided.
And the connection part of the said pedal unit is detachably fixed with respect to the said cylindrical part with the volt | bolt inserted in the through-hole on the said main body side and the through-hole on the said pedal unit side.

  The traveling practice bicycle described in Patent Document 2 and Patent Document 3 has a polygonal cylindrical connecting portion that projects from the pedal unit into a polygonal cylindrical cylindrical portion that extends downward from the body frame of the vehicle body. The connecting portion of the pedal unit is detachably fixed to the cylindrical portion by a bolt penetrating both.

Japanese Patent No. 5825596 JP2015-24686A Utility Model Registration No. 3093576

In the bicycle for running practice described in Patent Document 1, the portion where the vertically long slit and the columnar protrusion are in contact is limited to the upper half side surface of the columnar protrusion. There has been a problem that rattling is likely to occur in the engaged state due to vibration, deflection, wear, or the like due to such a lateral force.
In the bicycle for running practice described in Patent Document 2 and Patent Document 3, since the load concentrates on the bolt fixing the connecting portion and the cylindrical portion, the bolt is loosened or the bolt is easily damaged. There was a problem. Moreover, there exists a problem that manufacturing cost will rise if a polygonal cylindrical connection part and a polygonal cylindrical part are used.
Furthermore, the bicycle for running practice described in Patent Document 3 needs to tighten a plurality of bolts, and it is difficult to align the bolt insertion holes, and the work of tightening the bolts takes time and is troublesome. There was a problem of being bad.

Therefore, the main problem to be solved by the present invention is to increase the strength against the lateral force applied when the pedal is depressed, and the engagement state between the connecting portion formed on the bracket unit and the cylindrical portion of the body frame of the vehicle body It is to solve the rattling or the load is concentrated on the bolt that fixes both.
Therefore, the object of the present invention is to solve the above-described problems in the conventional bicycle for practice, and to easily align the bracket unit and the body frame of the vehicle body easily, and to easily establish a strong and stable engagement state thereof. An object of the present invention is to provide a bicycle for driving practice that can be obtained quickly and reliably.

  Further, another object of the present invention is to easily obtain a strong and stable engagement state even if only one bolt for detachably fixing the bracket unit to the body frame of the vehicle body is used. An object of the present invention is to provide a bicycle for driving practice that has excellent workability.

Another object of the present invention is to easily and firmly fix the protrusion that engages with the slit formed in the cylindrical portion of the main body frame at an accurate position with respect to the connecting portion of the bracket unit, and An object of the present invention is to provide a traveling practice bicycle that can be excellent in strength and durability.
Another object of the present invention is to provide a traveling practice bicycle in which the bracket unit can be easily attached and fixed to the main body frame in the correct direction that matches the longitudinal direction of the bicycle.

Another object of the present invention is as a bolt and nut for detachably fixing the bracket unit to the body frame of the vehicle body, and has a special shape and excellent strength and durability, and excellent detachability. It is to provide a bicycle for driving practice using things.
Another object of the present invention is to provide a bicycle for driving practice in which an adult can easily support a bicycle with a saddle.

  The present invention is "a bicycle for traveling practice in which the connecting portion formed to project from the bracket unit that pivotally supports the pedal crank is detachable from a cylindrical portion extending downward from the body frame of the vehicle body, A vertically long slit formed in the lower end portion of the cylindrical portion so as to extend along the longitudinal direction thereof, a body-side through hole formed in the cylindrical portion at a position above the slit, and the bracket unit A protrusion that is fitted in the slit and engages with the inner surface of the slit so as to be long in the vertical direction, and in the state where the slit and the protrusion are engaged, A bracket unit side through hole formed in the connecting portion of the bracket unit at a position coinciding with the through hole, the body side through hole and the bracket unit side Is to bolt to be inserted into holes, and the bracket unit removably fixed traveling bicycle practicing connection of "with respect to the tubular portion by a nut and key features.

  Further, the present invention is a travel practice bicycle in which a connecting portion protruding from a bracket unit that pivotally supports a pedal crank is detachable from a cylindrical portion that extends downward from a body frame of a vehicle body. A slit formed in a lower end portion of the cylindrical portion, a body-side through hole formed in the cylindrical portion at a position above the slit, and a connecting portion of the bracket unit. A projection that is fitted into the slit and engages with the entire inner surface of the slit, and the connecting portion of the bracket unit at a position that coincides with the through hole on the main body side when the slit and the projection are engaged. A through hole on the bracket unit side formed on the main body side and a bolt inserted into the through hole on the bracket unit side, and a nut by the nut It is an removably fixed traveling practice bicycle "key features of the connecting portion of the bracket unit for.

In the bicycle for driving practice according to the present invention, the slits of the cylindrical part are formed at two locations, and the protrusion is composed of a plate-like member that engages with both of the slits of the cylindrical part. The plate-like member may be formed by being fixed in a state of penetrating the connecting portion of the bracket unit.
In the traveling practice bicycle according to the present invention, the formation position of the through hole on the main body side and the through hole on the bracket unit side and the formation position of the slit may coincide with the front-rear direction of the vehicle body.
In the traveling practice bicycle according to the present invention, the ridge includes a rectangular shape having a vertically long cross section, another polygonal shape, an elliptical shape having a vertically long cross section, or a straight portion extending in the vertical direction. It may be oval.

In the traveling practice bicycle according to the present invention, one through hole on the main body side is formed on each of opposite side portions of the cylindrical portion, and the through hole on the bracket unit side is a connecting portion of the bracket unit. One is formed on each of the opposite sides of each of the above, and the rod-like nut (long nut or long nut having a head at one end) penetrating through all the through holes and a bolt screwed to the nut The connecting part of the bracket unit may be detachably fixed to the cylindrical part.
In the traveling practice bicycle of the present invention, the saddle attached to the main body frame may have a handle formed at the rear end thereof.

In the traveling practice bicycle of the present invention configured as described above, the ridges fitted in the slits formed in the cylindrical portion are engaged so as to be in long contact with the inner side surface of the slit in the vertical direction, and the load is applied. It is possible to avoid concentrating on a narrow area.
That is, in the bicycle for driving practice of the present invention, the engagement between the slit and the ridge can not only cope with the load and vibration from above, but also increases the strength against the lateral force applied when the pedal is depressed, It can be solved that rattling occurs in the engaged state between the connecting portion formed in the above and the cylindrical portion of the main body frame of the vehicle body, or that the load is concentrated on the bolt that fixes both.

Therefore, in the present invention, the connecting portion of the bracket unit can be firmly fixed to the cylindrical portion, and is excellent in stability and durability when used for a long time as a bicycle equipped with a normal pedal. A practice bicycle can be provided.
Furthermore, in the traveling practice bicycle of the present invention, the cylindrical portion and the connecting portion can be fixed by inserting one bolt into the through hole, so that the cylindrical portion on the vehicle body side and the pedal crank are pivoted. The supporting bracket unit can be easily and quickly attached and detached.

  Further, in the traveling practice bicycle of the present invention, two slits of the cylindrical portion are formed, the ridge is composed of a plate-like member that engages both of the slits of the cylindrical portion, When the plate-shaped member is formed by being fixed in a state of penetrating the connecting portion of the bracket unit, the fixing strength of the ridge can be increased, and further, the fixing position of the ridge is accurate. And efficiency of fixing work can be achieved.

  In the traveling practice bicycle according to the present invention, when the formation position of the through hole on the main body side and the through hole on the bracket unit side and the formation position of the slit are the same position as the longitudinal direction of the vehicle body, The operation of forming through holes and slits in the cylindrical part of the unit and the main body frame can be easily and easily performed, and the positioning and fixing of the bracket unit with respect to the cylindrical part is also easily and easily performed. be able to.

  In the bicycle for driving practice of the present invention, the ridge includes a rectangular shape having a vertically long cross section, other polygonal shapes, an elliptical shape having a vertically long cross section, or a straight portion extending vertically. In the case of an elliptical shape, the contact portion between the ridge and the inner surface of the slit can be obtained long, and the strength, stability and the connection portion between the bracket unit that pivotally supports the pedal crank and the body frame of the vehicle body can be obtained. It can be a bicycle for driving practice with excellent durability.

In the traveling practice bicycle according to the present invention, one through hole on the main body side is formed on each of opposite side portions of the cylindrical portion, and the through hole on the bracket unit side is a connecting portion of the bracket unit. The bracket unit connecting part can be attached to and detached from the cylindrical part by means of a rod-like nut that penetrates all the through holes and a bolt that is screwed to the nut. The bolts can be inserted easily and quickly, and the bolt threads are protected by the nuts and are not damaged. It can be set as the bicycle for driving practice excellent in the strength, stability and durability of the connecting portion with the main body frame.
That is, since the screw thread of the bolt is protected by the nut, it is possible to prevent the screw thread from being damaged and the bolt from being taken out.
Moreover, since the nut is cylindrical, the strength of the nut itself can be increased.
Furthermore, since the female thread portion is longer than a normal nut, the amount of biting with the bolt increases, and it is possible to prevent disengagement and increase the strength.
In addition, what is necessary is just to screw the bolt which has a head with respect to the both ends of the long nut, when using a long nut without a head.

In the traveling practice bicycle according to the present invention, when the saddle has a handle formed at the rear end thereof, an adult can easily support the bicycle by holding the saddle.
In the traveling practice bicycle of the present invention, instead of the vertically long slit, a slit that engages with a protrusion formed on the connecting portion of the bracket unit is adopted, and the protrusion fitted into the slit and the inner surface of the slit Even when the entire body is in contact with each other, a bicycle for driving practice that is excellent in strength, stability and durability of the connecting portion between the bracket unit that pivotally supports the pedal crank and the body frame of the vehicle body in the same manner as described above. be able to.

FIG. 1 is a view showing a cylindrical part of a traveling practice bicycle and a main part of a bracket unit of an embodiment embodying the present invention, and (A) is a perspective view showing a state before they are fitted together. (B) is a front view which shows the state before they are fitted, (C) is a front view which shows the state which fitted them. FIG. 2 is a diagram showing a traveling practice bicycle according to an embodiment of the present invention, in which a side view of a main part showing a state in which a bracket unit is removed from a tubular part of the traveling practice bicycle, It is a side view which shows the state which can be used as a normal bicycle which fixed the bracket unit to the cylindrical part of the bicycle. FIG. 3 is a view showing a cylindrical portion of a bicycle for practice of practice and an essential part of a bracket unit according to an embodiment of the present invention, and FIG. 3 (A) is a side view showing a state in which they are fitted, B) is a side view showing a state in which they are fitted together and the bolts and nuts, and (C) is a side view showing a state in which they are fitted together and the bolts and nuts are tightened. 4 (A) to 4 (D) are front views showing main portions of a cylindrical portion and a bracket unit of a bicycle for traveling practice according to another embodiment embodying the present invention. FIG. 5 is a perspective view showing a bottom side of a saddle of a traveling practice bicycle according to an embodiment of the present invention.

  The bicycle for traveling practice according to the present invention is preferably “running in which the connecting portion protruding from the bracket unit that pivotally supports the pedal crank is detachable from the cylindrical portion that extends downward from the body frame of the vehicle body. A practice bicycle, a vertically long slit formed in the lower end portion of the cylindrical portion so as to extend along the longitudinal direction thereof, and a main body side formed in the cylindrical portion at a position above the slit A through-hole, a protrusion formed in the connecting portion of the bracket unit and engaged with the inner surface of the slit so as to be long in the vertical direction, and the slit and the protrusion are engaged. The bracket unit side through hole formed in the connecting portion of the bracket unit at a position coinciding with the body side through hole, and the body side through hole An embodiment described below, which is a bicycle for traveling practice in which a connecting portion of the bracket unit is detachably fixed to the tubular portion by a bolt and a nut inserted through a through hole on the bracket unit side. It can be more concretely realized.

DESCRIPTION OF EMBODIMENTS Hereinafter, a traveling practice bicycle 1 embodying the present invention will be described with reference to the drawings.
A traveling practice bicycle 1 according to an embodiment of the present invention includes a main body frame 2 that is a main part constituting the vehicle body, and a handle post 3 that is an accessory part assembled to the main body frame 2, similarly to a normal bicycle. A handle 4, a front wheel 5, a rear wheel 6, a seat post 7, a saddle 8, a pedal crank 9, a pedal 9a, a gear 10, a chain 11, a brake system 12, and the like are provided.
The main body frame 2 is composed of a metal pipe, and a handle post 3 to which the handle 4 is fixed is attached to a front end portion of the main body frame 2.
The front wheel 5 is pivotally supported on a front fork 3 a formed at a lower portion of the handle post 3.

Near the central portion of the main body frame 2 is fixed a cylindrical portion 21 made of a cylindrical metal pipe arranged so as to extend in a slightly oblique vertical direction, and an upper end of the cylindrical portion 21 is fixed. On the side, a seat post 7 having the saddle 8 fixed to the upper end is fitted and fixed so as to be detachable.
In the traveling practice bicycle 1 of this embodiment, the saddle 8 attached to the main body frame 2 (cylindrical portion 21) has a handle 8a formed of a recess formed on the back side of the rear end portion. Yes.
Further, a connecting part 31 protruding from a bracket unit 30 that pivotally supports the pedal crank 9 is fitted to the lower end side of the cylindrical part 21 so as to be in close contact with the inner side of the cylindrical part 21, and the bracket unit. 30 is detachably fixed to the tubular portion 21 (see FIG. 2).

  The rear wheel 6 is pivotally supported at the rear end portion of the main body frame 2, and the rear wheel 6 is rotationally driven by the chain 11 attached to the gear 10 formed on one side of the pedal crank 9. It is like that. In addition, the pedal crank 9 in which the gear 10 is formed is generally called a gear crank.

The structure of the tubular portion 21, the bracket unit 30 and the connecting portion 31 of the traveling exercise bicycle 1 will be described in more detail below.
The cylindrical portion 21 has a vertically long slit 22 formed in a lower end thereof so as to extend along the longitudinal direction thereof, and a main body side formed in the cylindrical portion 21 at a position above the slit 22. A through hole 23 is provided.
In the traveling practice bicycle 1 of the present embodiment, the slits 22 of the cylindrical portion 21 are formed at a position corresponding to the front-rear direction of the traveling training bicycle 1, that is, at two locations on the tubular portion 21. Has been.
Furthermore, the formation positions of the through holes 23 on the main body side are each formed at one position, that is, at two positions at positions corresponding to the longitudinal direction of the vehicle body.

The bracket unit 30 is formed of a cylindrical metal pipe and has a function corresponding to a configuration generally called a bottom bracket. The pedal unit 9a includes two pedal cranks 9 that are pivotally supported at the tip end portions. A bearing structure capable of supporting the connecting crankshaft is provided.
In the traveling practice bicycle 1 of the present invention, the bracket unit 30 has a connecting portion 31 formed of a cylindrical metal pipe projecting upward on the upper surface thereof by welding.

The connecting portion 31 of the bracket unit 30 is formed with a ridge 32 that is fitted into the slit 22 and engages with the inner side surface (including the upper side and the left and right sides) of the slit 22 so as to be long in the vertical direction. .
Further, in a state where the slit 22 and the protrusion 32 are engaged, a through hole 33 on the bracket unit side is formed in the connecting portion 31 of the bracket unit 30 at a position coinciding with the through hole 23 on the main body side. Has been.
Here, the formation positions of the through holes 33 on the bracket unit side are each formed at one position, that is, at two positions at positions corresponding to the longitudinal direction of the vehicle body.

  And, in order to make the connecting portion 31 projecting from the bracket unit 30 that pivotally supports the pedal crank 9 detachable from the cylindrical portion 21 extending slightly obliquely forward and downward from the main body frame 2 of the vehicle body. The connecting portion 31 of the bracket unit 30 is detachably fixed to the cylindrical portion 21 by a bolt 40 inserted through the through hole 23 on the main body side and the through hole 33 on the bracket unit side. Yes.

Here, as the bolt 40, 1) adopting a configuration in which an elongated bolt having a normal shape having a thread on the outer surface is inserted into the through holes 23 and 33 and fixed with a short nut having a normal shape. 2) An elongated rod-like nut 41 having a smooth outer surface and a female screw hole 41a formed on the inner surface and having a head for retaining and rotating at one end is provided with the two through holes 23, A configuration in which the bolt 40 is screwed into the female screw hole 41a may be employed.
By adopting the configuration of 2) above, the thread of the bolt 40 is not damaged, and the occurrence of rattling due to the deterioration of the bolt 40 can be prevented. In addition, the workability of inserting the nut 41 through the through holes 23 and 33 is improved.
Moreover, since the screw thread of the bolt 40 is protected by the nut 41, it is possible to prevent the screw thread of the bolt 40 from being damaged and being unable to remove the bolt 40.
Moreover, since the nut 41 is cylindrical, the strength of the nut itself can be increased.
Further, since the female thread portion is longer than a normal nut, the amount of biting with the bolt 40 is increased, and it is possible to obtain the effects of preventing the disengagement and increasing the strength.

When the configuration 2) is adopted, the length of the elongated bar-shaped nut 41 is substantially the same as the length of the outer diameter of the tubular portion 21 except for the head portion, and the tubular portion 21. It is good to use what just penetrates (refer FIG.3 (B)).
In addition, it is good to use the volt | bolt 40 and the nut 41 which formed the hexagonal hole for rotation operation in the head of the said volt | bolt 40 and the nut 41. FIG.

In the traveling practice bicycle 1 of the present embodiment, the ridge 32 is composed of a single plate-like member 32 a that engages with both the slits 22 of the cylindrical portion 21, and the plate-like member. 32a penetrates the connecting part 31 of the bracket unit 30 and is fixed by welding in a state where both ends are exposed.
For this reason, the fixing strength and durability of the protrusion 32 with respect to the connection part 31 can be improved, and further, the accuracy of the fixing position of the protrusion 32 and the efficiency of the fixing operation can be achieved.

Next, a method for manufacturing the traveling practice bicycle 1 according to the embodiment will be described.
First, in order to manufacture the traveling practice bicycle 1 of the present invention, instead of the conventional method of manufacturing a bicycle in which a bottom bracket is directly welded to the lower end portion of the tubular portion 21 of the main body frame 2 into which the seat post 7 is fitted, The lower end portion of the cylindrical portion 21 of the main body frame 2 is left open.
And the slit 22 is formed in the lower end part of the said cylindrical part 21 by methods, such as punching in a rectangular shape, or cutting.
Further, the through hole 23 on the body side is formed in a circular shape at a position above the slit 22 by a method such as punching or cutting.

On the other hand, the bracket unit 30 can pivotally support a crankshaft connecting the two pedal cranks 9 by welding two cylindrical metal pipes so as to be orthogonal to each other in a T shape. The bearing structure and the cylindrical connecting portion 31 protruding upward on the upper surface side of the bracket unit 30 can be manufactured.
Then, in the vicinity of the lower end portion of the connecting portion 31, a method of punching or cutting a rectangular through hole 32b into which a metal plate material (plate-like member 32a) for forming the protrusion 32 can be fitted. Form with.

Further, the through hole 33 on the bracket unit side is formed in a circular shape at a position above the through hole 32b of the connecting portion 31 by a method such as punching or cutting.
In addition, a plate-like member 32a for forming the protrusion 32 is fitted into the rectangular through-hole 32b, and then both sides of the plate-like member 32a are fixed to the connecting portion 31 by spot welding. .
In a preferred embodiment, the plate-like member 32a is made of iron and has a lateral length of 30 mm, a height of 16 mm, and a thickness of 5 mm. And the outer diameter of the said connection part 31 is 25.4 mm, The length which the said plate-shaped member 32a exposes outside from the said rectangular-shaped through-hole 32b, and forms the said protrusion 32 is as follows. 2.3 mm. These numbers are reference values.
Further, by setting the dimensional tolerance between the slit 22 and the side surface of the protrusion 32 to about 0.5 mm, it is possible to prevent the rattling from occurring between the slit 22 and the protrusion 32.
Other components of the practice bicycle 1 according to the embodiment of the present invention can be easily manufactured by the same method as the conventional bicycle manufacturing method.

Next, a method of using the traveling practice bicycle 1 configured as described above will be described.
In the traveling practice bicycle 1 of this embodiment, it is possible to practice to be able to ride the bicycle with the bracket unit 30 and the chain 11 removed (the state shown in the upper side of FIG. 2). .
In other words, since there is no pedal, pedal crank and bottom bracket in a normal bicycle, the pedals do not get in the way when practicing to learn the sense of balance before learning the pedaling operation, and balance safely and efficiently. Practice to acquire methods such as sensation and steering wheel operation.

In the traveling practice bicycle 1 of the present embodiment, since the handle 8a is formed at the rear part of the saddle 8, an effect that an adult can easily hold and support the saddle 8 can be obtained.
After mastering methods such as balance feeling and steering wheel operation with the bicycle of the above form, the connecting portion 31 of the bracket unit 30 is inserted and fixed to the tubular portion 21, and the chain 11 is attached. It can be used as a bicycle.

When the bracket unit 30 is fixed to the cylindrical portion 21 as described above, the ridge 32 formed on the connecting portion 31 of the bracket unit 30 is fitted from the bottom in accordance with the slit 22 of the cylindrical portion 21. Thus, the cylindrical portion 21 and the bracket unit 30 can maintain a state of being firmly engaged with each other without rattling in the correct direction and the correct position.
Therefore, in the present invention, even when a cheap and easy-to-handle cylindrical pipe is used for the cylindrical portion 21 and the connecting portion 31, the engagement between the slit 22 and the protrusion 32 is only a load / vibration from above. Since it can handle loads and vibrations from the side, the strength against the lateral force applied when the pedal 9a is stepped on is increased, and the connecting portion 31 formed on the bracket unit 30 and the cylindrical portion of the body frame 2 of the vehicle body It is possible to solve the problem that rattling occurs in the engaged state with the bolt 21 and that the load is concentrated on the bolt 40 and the nut 41 that fix both.

  Next, since the bracket unit side through hole 33 is located at a position coincident with the body side through hole 23, an elongated rod-like nut 41 is inserted so as to penetrate both the through holes 23 and 33. And the connection part 31 of the bracket unit 30 is rapidly and firmly fixed with respect to the cylindrical part 21 by screwing the volt | bolt 40 which mounted the washer 42 in the female screw hole 41a of the said nut 41. As shown in FIG.

The present invention is not limited to the above embodiment, and the shape of the ridge 32 is appropriately changed as shown in FIGS. 4A and 4B, and the side surface (upper and left and right) of the ridge 32 is changed. The shape of the slit 22 that engages so as to be long in the vertical direction may be changed as appropriate.
The protrusion 32 shown in FIG. 4A has a substantially elliptical shape including a linear portion extending in the vertical direction. However, the protrusion 32 may be an elliptical shape having a vertically long cross section.
Furthermore, the protrusion 32 shown to FIG. 4 (B) is polygonal shape containing the linear part extended in an up-down direction.

In addition, the present invention is not limited to the above-described embodiment, and instead of the protrusions 32 that are long in the up and down direction, square or polygonal protrusions such as three, four, five, six, etc., As shown in FIG. 4C, the upper portion may be formed as a substantially square protrusion 34 having a semicircular shape.
In the case where the protrusion 34 is used instead of the protrusion 32 that is long in the vertical direction, the upper side and the left and right sides of the slit 22 are included with the tubular portion 21 and the connecting portion 31 engaged at the correct position. It may be formed in a shape and a position such that the entire inner side surface is in long contact with the side surface and the upper surface of the protrusion 34.
That is, both side surfaces from the upper end to the lower end (or near the lower end) of the protrusion 34 may be in contact with the inner side surface (including the upper side and the left and right sides) of the slit 22.
By making the contact portion between the protrusion 34 and the slit 22 longer as described above, the engagement of the slit 22 and the protrusion 34 can not only cope with the load and vibration from above, but also the left and right applied when the pedal 9a is depressed. The strength against the direction force can be increased.
And the cylindrical part 21 and the connection part 31 of the bracket unit 30 can maintain the state engaged firmly, without rattling in the correct direction and the correct position.

  Furthermore, the present invention is not limited to the above embodiment, and the position where the main body side through hole 23 and the bracket unit side through hole 33 are formed is a position corresponding to the traveling direction (front-rear position) of the vehicle body. It is not formed on the left and right side surfaces of the vehicle body, or as shown in FIG. 4D, the formation position of the protrusion 32 or the protrusion 34 is not the position corresponding to the traveling direction (front-rear position) of the vehicle body. It is possible to change such as forming it on the side surface side.

  Furthermore, the present invention can be carried out by appropriately changing the position, shape, size, material, number, etc. of the through holes, slits, protrusions, and protrusions without departing from the spirit of the present invention, or the cylindrical portion and the connecting portion. The shape may be changed as appropriate.

  INDUSTRIAL APPLICATION This invention can be utilized industrially suitably as a bicycle for driving practice.

1 Bicycle for practice 2 Body frame 3 Handle post 3a Front fork 4 Handle 5 Front wheel 6 Rear wheel 7 Seat post 8 Saddle 8a Handle 9 Pedal crank 9a Pedal 10 Gear 11 Chain 12 Brake system 21 Cylindrical part 22 Slit 23 Through hole 30 Bracket unit 31 Connecting part (bottom bracket adapter)
32 Projection 32a Plate-shaped member 32b Through hole 33 Through hole 34 on bracket unit side Projection 40 Bolt 41 Nut 41a Female screw hole 42 Washer

Claims (7)

A traveling practice bicycle in which a connecting portion protruding from a bracket unit that pivotally supports a pedal crank is detachable from a cylindrical portion extending downward from a body frame of a vehicle body,
A vertically long slit formed in the lower end portion of the cylindrical portion so as to extend along the longitudinal direction;
A through-hole on the main body side formed in the tubular part at a position above the slit;
A protrusion that is formed in the connecting portion of the bracket unit and is engaged with the inner surface of the slit so as to be long in the vertical direction by being fitted into the slit;
In the state where the slit and the protrusion are engaged, a through hole on the bracket unit side formed in the connecting portion of the bracket unit at a position coinciding with the through hole on the main body side,
With
For running practice, wherein the bracket unit connecting portion is detachably fixed to the cylindrical portion by a bolt and a nut inserted through the body side through hole and the bracket unit side through hole. bicycle.   Two slits of the cylindrical part are formed, and the protrusion is composed of a plate-like member that engages with both of the slits of the cylindrical part, and the plate-like member is the bracket. The traveling practice bicycle according to claim 1, wherein the bicycle is formed by being fixed in a state of penetrating through the connecting portion of the unit.   The travel according to claim 1 or 2, wherein the formation position of the through hole on the main body side and the through hole on the bracket unit side and the formation position of the slit are positions that coincide with the longitudinal direction of the vehicle body. Practice bicycle.   The protrusion is characterized in that the vertical cross section is a vertically long rectangular shape, other polygonal shape, the vertical cross section is a vertically long elliptical shape, or a substantially elliptical shape including a straight portion extending in the vertical direction. The traveling practice bicycle according to any one of claims 1 to 3.   One through hole on the main body side is formed on each opposite side portion of the cylindrical portion, and one through hole on the bracket unit side is formed on each opposite side portion of the connecting portion of the bracket unit. The connecting portion of the bracket unit is detachably fixed to the cylindrical portion by a rod-shaped nut that passes through all the through holes and a bolt that is screwed to the nut. Item 5. The traveling practice bicycle according to any one of Items 1 to 4.   The saddle mounted on the main body frame has a handle formed at a rear end thereof, and the bicycle for traveling practice according to any one of claims 1 to 5. A traveling practice bicycle in which a connecting portion protruding from a bracket unit that pivotally supports a pedal crank is detachable from a cylindrical portion extending downward from a body frame of a vehicle body,
A slit formed in the lower end of the cylindrical portion,
A through-hole on the main body side formed in the tubular part at a position above the slit;
A protrusion that is formed in the connecting portion of the bracket unit, is engaged with the slit so as to be in contact with the entire inner surface of the slit;
In the state where the slit and the projection are engaged, a through hole on the bracket unit side formed in the connecting portion of the bracket unit at a position coinciding with the through hole on the main body side,
With
For running practice, wherein the bracket unit connecting portion is detachably fixed to the cylindrical portion by a bolt and a nut inserted through the body side through hole and the bracket unit side through hole. bicycle.

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