JPH0616221A - Roller conveyor - Google Patents

Abstract

PURPOSE:To facilitate maintenance and always perform stable carrying without play by making constitution in which attaching/detaching a bracket, operating a fixture, and mounting/demounting a roller can be performed from the upper side. CONSTITUTION:This roller conveyor is provided with a main body frame, having a right and left pair of side frames 11A and 11B, and a roller 30 group between both the side frames. Parts-to-be-engaged 14A and 14B are formed on the upper parts of the side frames 11A and 11B, and brackets 20A and 20b for freely supporting a roller shaft 31 are formed placeably on the side frames 11A and 11B. Projection parts 21a, and 21b, freely engaging from the upper side with the parts-to-be-engaged 14A and 14B form the plural portions in the bottom surface of this bracket 20, are vertically provided, and the brackets 20A and 20B are fixed to the side frames 11A and 12B via a fixture 23, in which a part is engaged with the parts-to-be-engaged 14A and 14B and which is penetrating two projection parts 21a and 21b. The position of a roller shaft 31 is located at the upper side of the side frame upper surface, a large space is formed between a carrying surface and the side frame upper surface, and the fork etc.,of a transfer device can be directly operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a main body frame having a pair of left and right side frames, and a group of rollers arranged between the side frames, and is used for directly conveying an object to be conveyed or through a pallet. It relates to a roller conveyor used for, for example.

[0002]

2. Description of the Related Art Hitherto, as a roller conveyor of this type, a structure disclosed in, for example, Japanese Utility Model Laid-Open No. 1-111609 has been provided. In this conventional structure, the main body frame is composed of a pair of left and right side frames and a base frame that connects the lower parts of these side frames. Then, the support frames are arranged in abutting manner on the inner surface sides of the side frames which face each other, and then fixed by bolts and nuts, and the transport rollers are arranged between the support frames. Further, a driving body or the like is arranged on one side frame, and a transmission roller which is interlocked with the driving body and which can be connected / disconnected to the carrying roller is provided on one supporting frame.

[0003]

According to the above-mentioned conventional structure, since the supporting position of the roller shaft is lower than the upper surface of the side frame, the conveyance surface formed by the group of rollers and the upper surface of the side frame. There is only a small space between them. Therefore, when the transferred object is taken out laterally with respect to the transfer path, for example, the fork of the transfer device or the locking claw of the transfer robot cannot directly act, and the transfer conveyor is orthogonal to the transfer path. Cannot be installed (chain conveyor, etc.).

Therefore, conventionally, a lift device for lifting an object to be transferred and a lift device for lifting a transfer conveyor are provided on the transfer path, which makes the entire structure large and complicated, and controls it. Becomes complicated,
Furthermore, the total working time was increased by the insertion of the lift time.

Further, both supporting frames supporting the conveying rollers are separately attached to and detached from the side frames, respectively.
Wearing each by operating the bolts and nuts from the inside is troublesome, and detachment is also troublesome, and maintenance etc. cannot be performed easily.

An object of the present invention is to smoothly take out a conveyed object laterally with respect to the conveying path without employing a lift device, and to easily and easily attach and detach the roller to and from the side frame. The point is to provide a roller conveyor.

[0007]

In order to achieve the above object, the roller conveyor of the first invention is a roller conveyor comprising a main body frame having a pair of left and right side frames and a group of rollers arranged between the both side frames. In addition, a fitted portion is formed on the upper portion of the side frame, and a bracket that can support the roller shaft of the roller is formed on the side frame so that the bracket can be placed on the side frame. A protrusion that can be fitted into the fitting portion from above is provided vertically, and the bracket is fixed to the side frame via a fixture that partially fits into the fitted portion and penetrates one protrusion. ing.

In the roller conveyor according to the second aspect of the present invention, the fitting portion into which the protrusion can be fitted from above is formed by a dovetail groove portion formed in the length direction of the side frame. Further, in the roller conveyor according to the third aspect of the present invention, the protruding portion that can be fitted into the fitted portion from above is formed in a circular shape.

[0009]

According to the structure of the first invention described above, in assembling the roller conveyor, the bracket is first lowered with respect to the upper surface of the side frame, and the plurality of protrusions provided on the lower surface are fitted to the fitted portion. Then, the bracket is tightly fitted from above, and then the bracket is fixed to the side frame by applying a fixing tool penetrating one projection portion from above to fix the bracket to the side frame. The work of removing the roller from the bracket and the work of removing the bracket from the side frame can be performed by reverse operation.

The object to be conveyed can be conveyed by being supported by a group of rollers. During the conveyance, the moment force generated in the bracket via the roller shaft due to the frictional force acting on each roller is to be fitted. It can be received by fitting a plurality of protrusions into the joints. Therefore, although the brackets are each fixed through one fixing tool, they can receive the moment force that is likely to occur due to one point fixing.

Further, in the assembled state, the position of the roller shaft supported by the bracket is above the upper surface of the side frame, and a large space is formed between the conveying surface formed by the group of rollers and the upper surface of the side frame. obtain. Therefore, using this space, for example, the fork of the transfer device or the locking claw of the transfer robot can directly act on the object to be transferred, and a transfer conveyor orthogonal to the transfer path can be provided. You can

According to the structure of the second aspect of the present invention, the position of the bracket can be corrected by sliding the bracket in the front-rear direction with respect to the side frame with the plurality of projections fitted in the dovetail groove.

Further, according to the structure of the third aspect of the present invention, the side frame may be made of iron in which the fitted portion is formed by the round hole into which the protrusion can be fitted.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 8, reference numeral 1 denotes a machine frame, which is a pedestal 2 in which a pair of right and left and a plurality of front and rear are erected at predetermined intervals and left and right pedestals 2
The left and right members 3 for connecting the intermediate portions of the above and the front and rear members 4 for connecting between the front and rear lower portions of the predetermined pedestal 2 are formed. An adjustable landing body 5 is provided at the lower end of each pedestal 2, and a guide body 6 is provided between the inner surfaces of the upper ends of the front and rear pedestals 2. An idle roller conveyor 10 and a drive roller conveyor 40 are arranged so as to be laterally distributed between the upper surfaces of the left and right members 3.

The idle roller conveyor 10 includes a pair of left and right side frames 11A and 11B, as shown in FIGS.
A body frame 13 is constituted by an end plate 12 that connects the ends of the side frames 11A and 11B. Both side frames 11A and 11B are made of aluminum, and the upper dovetails of the first dovetail groove portions 14A and 14B (an example of a fitted portion) are open upward, and the lower portions thereof are downwardly open second dovetail groove portions 15A and 15B, respectively. It is formed in the length direction of the side frames 11A and 11B. The main body frame 13 is fixed to the machine frame 1 side by screwing a bolt 16 passed through the left and right members 3 from below into a nut body 17 arranged in the second dovetail groove portions 15A and 15B. .

Brackets 20A, 20B made of synthetic resin are provided on the side frames 11A, 11B at a plurality of positions in the length direction of the main body frame 13, and the brackets 20A, 20 facing each other on the left and right sides.
A roller 30 is supported between B in a freely rotatable manner. Here, the roller 30 is composed of a roller shaft 31 and a roller body 32 that is fitted onto the roller shaft 31 so as to freely rotate.

The brackets 20A and 20B are integrally provided with projecting portions 21a and 21b at two front and rear positions (a plurality of positions) on the bottom surface thereof. These protrusions 21a, 21b are formed in a circular shape, and can be tightly fitted into the slit-shaped openings of the first dovetail grooves 14A, 14B from above. Each of the brackets 20A and 20B has a single protrusion, in this case, one of the brackets 20A, which is the front protrusion 21a, and the other bracket 20B, which is the rear protrusion 21b. Is forming.

Both brackets 20A and 20B are fixtures.
It is fixed to both side frames 11A and 11B via 23 so as to be detachable and positionally changeable (sliding) in the frame length direction. Here, the fixing tool 23 is in the first dovetail groove sections 14A and 14B. And a bolt 25 that is inserted into the through hole 22 from above and that can be screwed into the nut body 24. Further, on both brackets 20A and 20B, a concave support portion 26 capable of supporting the roller shaft 31 dropped from the upper side is provided.
However, it is formed by opening the upper side and the inner side.

The drive roller conveyor 40 is shown in FIGS.
As shown in FIG. 4, a body frame 43 is configured by a pair of left and right side frames 41A and 41B and an end plate 42 that connects end portions of the side frames 41A and 41B. Both side frames 41A, 41B are made of aluminum, and engaging grooves 44A, 44B with open upper surfaces are formed in the intermediate portions of the inner surfaces facing each other, and the first dovetail groove (fitted portion) with open upper surface is formed at the upper portion. An example) 45A and 45B, and the second dovetail groove portions 46A and 46B, which are open downward, at the bottom are side frames, respectively.
It is formed in the length direction of 41A and 41B. Then, the body frame 43 is provided with bolts 47 that are passed through the left and right members 3 from below.
Is arranged in the second dovetail groove portion 46A, 46B.
It is fixed to the machine frame 1 side by being screwed into.

On one side frame 41A, a pair of guide rails 50a and 50b are arranged in the longitudinal direction of the frame on the inner surface side of the lower part thereof via mounting portions 49a and 49b, respectively. The other side frame 41B is formed to have a low height without a mounting portion or the like. Both guide rails 50a, 50
b is a guide for supporting and guiding a chain (an example of a driving body) 51 stretched between driven chain wheels provided at both ends of the main body frame 43, and a drive which meshes with the chain 51 at an appropriate position of the main body frame 43. A drive device 52 including a chain wheel and a motor, and a control device 53 are provided.

A support frame 60 made of synthetic resin is disposed between the both side frames 41A and 41B, and the support frame 60 supports a roller 56 in a freely rotatable manner. The unit body 55 is configured, and the unit body 55 is arranged at a plurality of positions in the length direction of the main body frame 43. Here, the roller 56 is composed of a roller shaft 57 and a roller body 58 which is fitted onto the roller shaft 57 so as to freely rotate.

The support frame 60 includes a pair of connecting portions 61A and 61B which can be placed on both side frames 41A and 41B, and these connecting portions 61.
A pair of vertical plate portions 62A, 62B hanging from the inner ends of A, 61B
And a horizontal plate portion 63 that is continuously provided from the lower portion of the other vertical plate portion 62B toward the lower portion of the one vertical plate portion 62A, and is provided continuously from the inner surface of the lower half of the one vertical plate portion 62A toward the inside. And the lower end is the horizontal plate 63
It is formed in a U shape in a front view by a pair of front and rear cover plate portions 64 connected to the edge portions of the.

Here, the connecting portions 61A and 61B are integrally provided with projecting portions 65a and 65b at two front and rear positions (a plurality of positions) on the bottom surface thereof. These protrusions 65a and 65b are formed in a circular shape,
The first dovetail groove portions 45A and 45B can be tightly fitted into the slit-shaped opening portions from above. In each case, a single through-hole 66 is formed in each of the protrusions, in this case, one connecting portion 61A is the front protrusion 65a and the other connecting portion 61B is the rear protrusion 65b. ing.

Both connecting portions 61A and 61B are fixed to both side frames 41A and 41B through a fixture 67 so as to be detachable and positionally changeable (sliding) in the frame length direction.
Here, the fixture 67 is composed of a nut body 68 arranged in the first dovetail groove portions 45A and 45B, and a bolt 69 which is inserted into the through hole 66 from above and is screwed into the nut body 68. . Further, a concave support portion 70 capable of supporting the roller shaft 57 that is dropped from the upper side is formed in one of the connecting portions 61A, with the upper portion and the inner portion opened, and the other connecting portion 61B includes
A hole-shaped support portion 71 capable of supporting the roller shaft 57 inserted from the inside is formed with the inside opened.

The support frame 60 is provided with a transmission device 80 which is interlocked with the chain 51 and is capable of contacting the roller body 58 from below. That is, in the transmission 80, the support frame 60 is also used as a main body, and a horizontal bearing hole 81 is formed in the lower part of one vertical plate portion 62A, and a horizontal support shaft is formed in the bearing hole 81.
The support shaft 82 is vertically swingable by fitting one end of the support shaft 82. The other end of the support shaft 82 is fitted into a vertical recess 83 formed in the other vertical plate portion 62B to regulate the swing range of the support shaft 82 in the vertical direction.

A passive chain ring 84, which is an example of a passive body, is rotatably attached to the support shaft 82, and a transmission roller 85, which is an example of a transmission body, is fitted onto the protruding boss portion of the passive chain ring 84. Therefore, both 84 and 85 are integrally rotatable. The passive chain wheel 84 always meshes with the chain 51 from above. The transmission roller 85 is made of urethane rubber, and the outer periphery of the transmission roller 85 can be brought into contact with and separated from the lower portion of the outer periphery of the roller body 58. Cylinder device using air to make contact and separation
86 is interposed between the cylinder rubber receiver 87 attached to the outer end of the support shaft 82 and the lateral plate portion 63. A transmission device 80 is configured by the above 81 to 87.

The unit bodies 55 are arranged every other side in the lengthwise direction of the side frames 41A and 41B, and between the unit bodies 55, rollers similar to those of the idle roller conveyor 10 are provided.
30 is provided via brackets 20A and 20B. However, the drive roller conveyor 40 is all a unit body 55.
May be provided. The transported object 90 includes, for example, a pallet 91 and an article 92 placed on the pallet 91. The pallet 91 may not be used for transportation.

The operation of the above configuration will be described below.
To assemble the above-mentioned idle roller conveyor 10, first, end plates
The left and right members 3 are formed by inserting the body frame 13 in which both side frames 11A and 11B are integrated by 12 through the bolt 16 and the nut body 17.
Fix it in place. Then both sides frame 11A, 11B
Fix the brackets 20A, 20B in place on the upper surface of the bracket. That is, the brackets 20A and 20B are the side frames 11A and 11B.
The plurality of protrusions 21a, 21b provided on the lower surface of the first dovetail groove are closely fitted into the slit-shaped opening portions of the first dovetail groove portions 14A, 14B from above. The lowering ends when the lower surfaces of the brackets 20A and 20B come into contact with the upper surfaces of the side frames 11A and 11B.

Next, the brackets 20A and 20B are formed on both side frames 11
The position is corrected by sliding in the front-back direction with respect to A and 11B. Prior to this position correction, the bolt 25 passed through the through hole 22 from above is loosely screwed into the nut body 24 arranged in the first dovetail groove portions 14A and 14B, and therefore the bracket 20
When A and 20B slide, the bolt 25 and the nut body 24 move integrally. After adjusting the position as described above, bolt 25
Are strongly screwed together, so that the brackets 20A and 20B are fitted on both side frames 11
It is fixed to A and 11B.

In this way, the roller 30 is incorporated between the brackets 20A and 20B fixed to the side frames 11A and 11B. That is, the concave support portion 26 formed on both brackets 20A and 20B.
In contrast, it is performed by dropping both ends of the roller shaft 31 from the upper side. In addition, from both brackets 20A, 20B to roller
Work to remove 30 or bracket 20 from side frames 11A and 11B
The work of separating A and 20B can be performed by the reverse operation to the above.

In assembling the above-mentioned drive roller conveyor 40, first, a body frame 43 constituted by integrally forming both side frames 41A and 41B by an end plate 42 is provided with a predetermined distance between the left and right members 3 via a bolt 47 and a nut body 48. Fixed in position. Next, the unit body 55 is fixed at a predetermined position between the both side frames 41A and 41B with the chain 51 and the like arranged.

That is, the unit body 55 having the transmission 80 and the roller 56 incorporated therein has the vertical plate portions 62A, 62 of the support frame 60.
B to face the inner surfaces of the side frames 41A and 41B,
It is inserted between 41B from above. Near the end of this insertion, the lower ends of the vertical plate portions 62A, 62B are engaged with the locking grooves 44A, 44B from above, and the plurality of protrusions 65a, 65b provided on the lower surfaces of the connecting portions 61A, 61B are First dovetail groove 45A, 45
The slit-shaped opening portion of B is tightly fitted from above. The insertion ends when the lower surfaces of the connecting portions 61A and 61B come into contact with the upper surfaces of the side frames 41A and 41B, and at this time, the passive chain wheel 84 meshes with the chain 51 from above.

Next, the unit body 55 is composed of both side frames 41A and 41B.
The position is corrected by sliding it in the front-back direction. Before performing this position correction, the bolt 69 that has passed through the through hole 66 from above is loosely screwed into the nut body 68 arranged in the first dovetail groove portions 45A and 45B, and therefore, when the unit body 55 slides, the bolt 69 It moves integrally with the nut body 68. After the position correction is performed as described above, the bolt 69 is strongly screwed, so that the unit body 55 is fixed between the both side frames 41A and 41B.

The unit body 55 includes a support frame 60 and rollers 56.
The roller 56 is fixed between the side frames 41A and 41B in a state where the roller 56 is incorporated, but the roller 56 may be incorporated into the support frame 60 fixed between the side frames 41A and 41B. In either case, the roller 56 is assembled to the support frame 60 by first connecting the other connecting portion.
By inserting the other end of the roller shaft 57 from the inside into the hole-shaped support portion 71 formed in 61B, and then dropping one end of the roller shaft 57 from the upper side into the concave support portion 70 formed in one of the connecting portions 61A. Done.

And between the unit body 55, the bracket 20
A roller 30 is arranged via A, 20B and the like. The work of removing the roller 56 from the support frame 60 and the work of removing the support frame 60 from the side frames 41A and 41B can be performed by the reverse operation to the above.

The object 90 to be conveyed is conveyed by the conveyor device assembled as described above as follows. That is, the drive device 52 is actuated to move the chain 51, and the group of passive chain wheels 84 meshing with the chain 51 is supported as a spindle.
Rotate around 82. Then, the transmission roller 85 is integrally rotated together with the passive chain wheel 84. At this time, the cylinder device 86 is contracted to separate the transmission roller 85 from the roller body 58, so that the rotational force of the transmission roller 85 is not transmitted to the roller 56.

Then, by extending the cylinder device 86 and bringing the transmission roller 85 into contact with the roller body 58 from below, the rotational force of the transmission roller 85 is transmitted to the roller 56 and the roller 56 is forcedly rotated. . Therefore, the transported object 90 supported across the idler roller conveyor 10 and the drive roller conveyor 40 is guided and transported by the guide body 6 by the driving force on the drive roller conveyor 40 side.

During such conveyance, each roller 30,
The frictional force acting on 56 causes momentary force to be generated in the brackets 20A, 20B and the connecting portions 61A, 61B via the roller shafts 31, 57. This momental force is generated by the first dovetail groove portions 14A, 14B.
Two protrusions 21a, 21b, 65 on B, 45A, 45B respectively
It can be received because a and 65b are fitted. Therefore, although the brackets 20A, 20B and the connecting portions 61A, 61B are fixed through the single fixing members 23, 67, respectively, they can receive the moment force that is likely to be generated by one point.

In the roller conveyor assembled and used as described above, the bracket
The positions of the roller shafts 31, 57 supported by the 20A, 20B and the connecting portions 61A, 61B are the upper surfaces A of the side frames 11A, 11B, 41A, 41B.
A large space S can be formed between the conveying surface B formed by the group of rollers 30, 56 and the upper surface A of the side frames 11A, 11B, 41A, 41B. Therefore, using this space S, for example, a fork of a transfer device or a locking claw of a transfer robot can directly act on the object 90 to be transferred, and a transfer conveyor orthogonal to the transfer path can be provided. It can be arranged. At that time, at the transfer position of the transported object 90, the guide body 6
Are partially removed.

The object 90 to be conveyed is conveyed as described above. At that time, the conveying route is divided into a plurality of zones, and the transmission roller 85 is set for each zone based on the detection by the detecting device of each zone. When the abutting movement or the separating movement is performed, the conveyance form in which the conveyed object 90 is sequentially fed while being stored can be adopted.

The idle roller conveyor 10 as in the above embodiment
When the conveyor device is configured by arranging the drive roller conveyor 40 and the drive roller conveyor 40 in parallel, the distance between the conveyors 10 and 40 can be freely adjusted, and the shape of the pallet 91 can be flexibly accommodated. However, in the present invention, the idle roller conveyor
This idle roller conveyor 10
It may be a free conveyor type in which a transport path is formed only by itself, or may be a drive conveyor type in which a drive belt is pressed against the lower surface of a group of freely rotatable rollers 30.

In the above embodiment, the protrusions 21a, 21b, 65
a and 65b are fitted into the fitted portion which can be fitted from above by the side frames 11A,
First dovetail groove portion 14 formed in the length direction of 11B, 41A, 41B
Although it is composed of A, 14B, 45A, 45B, in the first invention, for example, iron side frames 11A, 11B, 41A, 41B are used.
It may be a fitted portion in which a round hole in the vertical direction is formed on the upper surface of the. In the first invention, the first dovetail grooves 14A, 14
B, 45A, 45B, protrusions 21a, 21 that can be freely fitted from above
b, 65a, 65b do not necessarily have to be circular, and may be, for example, rectangular.

In the above-mentioned embodiment, the passive chain ring 84 and the transmission roller 85 are used as the transmission device 80 for transmitting the power of the chain 51 to the roller 56. It may be a built-in format. The drive roller conveyor 40 may be of a type that does not have the protrusions 65a and 65b, or may be of a type that causes the fixture 67 to act on each of the plurality of protrusions 65a and 65b.

[0044]

According to the first aspect of the present invention having the above-described structure, the roller conveyor has the bracket mounted on or detached from the side frame from above, and one fixing member acts from above. By attaching and detaching the roller to and from the bracket from above, assembly or disassembly can be easily and easily performed, and maintenance or the like can be easily performed.

The brackets can be quickly fixed by one fixing tool respectively, but the moment force that tends to be generated by one point, that is, the conveyed object supported by the roller group, is conveyed through the roller shaft. The moment force generated in the bracket can be received by the plurality of projections fitted in the fitted portion, and stable transportation can be always performed without rattling.

Further, in the assembled state, the position of the roller shaft supported by the bracket can be set higher than the upper surface of the side frame, and a large space is formed between the conveying surface formed by the roller group and the upper surface of the side frame. it can. Therefore, by utilizing this space, for example, the fork of the transfer device or the locking claw of the transfer robot can directly act on the transferred object, and a transfer conveyor orthogonal to the transfer path can be provided. It can be provided.

According to the structure of the second aspect of the present invention, the bracket easily fits in the carrying direction by sliding the projections into the dovetail groove and then sliding the projections in the front-back direction with respect to the side frame. Can be done.

Further, according to the structure of the third aspect of the present invention, the side frame can easily be made of iron in which the fitting portion is formed by the round hole into which the protrusion can be fitted.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a transmission unit of an idle roller conveyor according to an embodiment of the present invention.

FIG. 2 is a plan view of the transmission unit.

FIG. 3 is a partially cutaway inner side view of a bracket of the transmission unit.

FIG. 4 is a vertical sectional front view of a transmission unit of the drive roller conveyor.

FIG. 5 is a plan view of the transmission unit.

FIG. 6 is a partially cutaway inner side view of the one coupling portion of the transmission unit.

FIG. 7 is a partially cutaway inner side view of the other coupling portion of the transmission unit.

FIG. 8 is a perspective view of the entire conveyor device.

[Explanation of symbols]

 1 Machine frame 6 Guide body 10 Idler roller conveyor 11A, 11B Side frame 13 Main body frame 14A, 14B 1st dovetail groove (fitted part) 20A, 20B Bracket 21a, 21b Projection 22 Through hole 23 Fixing tool 26 Concave support Part 30 Roller 31 Roller shaft 32 Roller body 40 Drive roller conveyor 41A, 41B Side frame 43 Body frame 45A, 45B 1st dovetail groove (fitted part) 51 Chain (drive body) 52 Drive device 55 Unit body 56 Roller 57 roller Shaft 60 Support frame 61A, 61B Coupling part 65a, 65b Projection part 66 Through hole 67 Fixing tool 70 Concave support part 71 Hole support part 80 Transmission device 84 Passive chain wheel (passive body) 85 Transmission roller (transmission body) 90 Transported object Object A Side frame upper surface B Transport surface C Space

Claims (3)

[Claims] 1. A roller conveyor comprising a main body frame having a pair of left and right side frames, and a group of rollers arranged between the side frames, wherein a fitted portion is formed on an upper portion of the side frame. A bracket that can support the roller shaft is formed so that it can be placed on the side frame, and projections that can be fitted into the fitted portion from above are vertically provided from a plurality of bottom surfaces of the bracket to attach the bracket. A roller conveyor, characterized in that it is fixed to the side frame via a fixture that partially fits into the fitted portion and penetrates one projection. 2. The roller conveyor according to claim 1, wherein the fitting portion into which the protrusion is fitted from above is formed by a dovetail groove portion formed in the lengthwise direction of the side frame. 3. The roller conveyor according to claim 1, wherein a protrusion which can be fitted into the fitted portion from above is formed in a circular shape.