JP2000311728A - Structure to prevent incorrect mounting of terminal fittings - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a structure capable of efficiently assembling terminal fittings efficiently. SOLUTION: A pair of inner frames 3 are assembled to an outer frame 4. Two types of terminal fittings 1 and 2 having different outer shapes are mounted on each inner frame 3. The inner frame 3 is provided with a terminal identification portion that allows only regular terminal fittings to be mounted according to the outer shape of the terminal fittings 1 and 2. The outer wall of the inner frame 3 is provided with combination portions 19 and 27 having different outer shapes. On the other hand, the outer frame 4 is provided with combination receiving portions 21 and 28 to which only the regular inner frame 3 can be attached according to the combination portions 19 and 27. Further, the pair of outer frame bodies 4 are assembled to the casing 34 in parallel on the left and right.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for preventing erroneous assembly of terminal fittings.

[0002]

2. Description of the Related Art FIG. 16 shows a structure for preventing erroneous assembly of terminal fitting 100 disclosed in Japanese Utility Model Laid-Open No. 23431/1993. The four types of terminal fittings 100 shown in FIG.
Identification protrusions 101 are provided at different positions. On the other hand, the base 102 on which the terminal fitting 100 is mounted is provided with a receiving portion 103 for receiving the terminal fitting 100 and an identification recess 104 complementary to each identification projection 101. Thus, the identification protrusion 101 and the identification recess 104 are provided.
By combining each of the terminal fittings 100 with only the proper position, erroneous assembly is prevented.

[0003]

However, in the above-described structure, as the number of the terminal fittings 100 increases, the number of the identification protrusions 10 increases.
1 and the identification recess 104 must be increased, and a mold or the like must be manufactured accordingly.

In the above structure, the terminal fittings 100 and the receiving portions 103 are formed in a one-to-one correspondence regardless of the type of the terminal fittings 100. For this reason, for example, when several types of terminal fittings form a group, and there are a plurality of groups (in such a case, the terminal fittings are usually arranged collectively for each group in many cases), Each terminal fitting 100 and the receiving part 103 must be matched one-to-one, which is a complicated assembling operation. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a structure capable of efficiently erroneously attaching terminal fittings.

[0005]

According to a first aspect of the present invention, there is provided a terminal fitting erroneous assembling prevention structure which comprises a plurality of terminal fittings of the same number. And a plurality of terminal identification units provided for each group, and provided with a terminal identification unit that can be fitted when the arrangement of the terminal fittings in each group is correct, and that cannot be fitted when the arrangement is incorrect. A plurality of inner frames having a form, a mating terminal metal group that can be individually connected to each of the terminal metal fittings is arranged, and when the arrangement of each of the inner frame bodies is correct, the fitting can be performed. In some cases, a plurality of outer frames formed in a common form provided with a group identification unit that is determined to be unfittable, and each outer frame in a state where the inner frame is assembled are erroneously inserted. Frame that regulates arrangement And a casing provided with a separate part, wherein the frame body identification part is one side of an uneven form having the same number as the outer frame body and each having a different form, and is individually fitted with each other. In the case of a different combination, a receiving portion on the other side of the concave-convex shape that makes fitting impossible is formed on the inner frame.

According to a second aspect of the present invention, in the first aspect, the casing is capable of incorporating two of the outer frames in parallel, and has an inner surface having a height. The frame body identification portions formed in different pillar shapes are erected, and the outer frame body is formed with identification portion introduction recesses capable of receiving both of the frame body identification portions toward the inner frame body, and In the case where the arrangement of the outer frame with respect to the casing is regular, the inner frame incorporated in the frame is fitted with the corresponding frame identification portion on the corresponding side, and when the arrangement is incorrect. Is characterized in that the receiving portion is provided which makes it impossible to fit by hitting the incompatible frame identification portion.

[0007]

According to the first aspect of the present invention, first, a terminal fitting is mounted on each of the plurality of inner frames. At this time, a terminal identification portion for identifying the form of the terminal fitting is provided on the inner frame, whereby the terminal fitting is fitted into a proper place. Next, the inner frame to which the terminal fittings are attached is assembled to the outer frame. At this time, the outer frame is provided with a group identification portion for identifying the mounting position of the inner frame, whereby the inner frame is fitted in a regular place. Finally, the outer frame is mounted on the casing. At this time, the casing frame identification portion
The outer frame is fitted into a proper position of the casing by identifying the uneven shape between the outer frame and the receiving portion of the inner frame (not the outer frame). In this way, since the outer frame is distinguished from the inner frame by the casing, the outer frames have the same form. That is, if a plurality of types of smaller inner frames are formed, the same type of larger outer frame may be used, so that the cost can be reduced as a whole.

According to the second aspect of the present invention, the columnar frame identification portion provided on the casing is identified by the receiving portion of the inner frame, and the arrangement of the outer frame can be a regular arrangement.

[0009]

Next, an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 shows an inner frame 3 to which two types of terminal fittings 1 and 2 are attached,
This shows a state before the pair of outer frame bodies 4 and the casing 34 are assembled. A pair of terminal fittings 1 and 2 can be mounted on the inner frame 3, and the outer frame 4 has
A pair of inner frames 3 can be mounted. Further, a pair of outer frame bodies 4 can be mounted on the casing 34.

<Terminal Fittings> FIG. 2 shows terminal fittings 1 and 2. In the present embodiment, a first terminal fitting 1 and a second terminal fitting 2 having different external shapes are provided. The first terminal fitting 1 is longer and wider than the second terminal fitting 2. Each of the terminal fittings 1 and 2 is connected to a core wire 5 </ b> A exposed at one end of the electric wire 5. Bolt through holes 7 through which bolts 6 protruding from the outer frame body 4 can be inserted are provided at the tips of the terminal fittings 1 and 2. Both terminal fittings 1 and 2
One pair forms one group, and is mounted on the inner frame 3 for each group.

<Inner Frame> Next, the configuration of the inner frame 3 will be described with reference to FIGS. The inner frame 3 is integrally formed of synthetic resin, and can accommodate a pair of terminal fittings 1 and 2 therein. The inner frame 3 includes a main body 10 provided with terminal housings 8 and 9 to which the terminal fittings 1 and 2 can be mounted, and a hinge 1 with respect to the main body 10.
2 and an outer frame closing portion 14 which is also rotatable by a hinge 13 with respect to the main body 10.

The main body 10 is provided with a first terminal accommodating portion 8 capable of accommodating the first terminal fitting 1 and a second terminal accommodating portion 9 capable of accommodating the second terminal fitting 2. The side walls of the terminal accommodating portions 8 and 9 are formed as uneven terminal identification portions 8A and 9A according to the outer shapes of the terminal fittings 1 and 2, respectively. Therefore, if the positions of the terminal fittings 1 and 2 are different, it is impossible to mount the terminal fittings 1 and 2 on the inner frame 3. In addition, a through hole 36 (corresponding to a “receiving portion” in the present invention) is provided in the center wall 35 of each of the terminal accommodating portions 8 and 9, penetrating in the front and back directions of the inner frame 3. Through hole 3
6 has a substantially square shape, and is slightly larger than the cross-sections of the frame identification portions 37A and 37B projecting from the casing 34 described later.

In FIG. 3, an engagement recess 15 for engaging the lid 11 is formed in the left side wall of the main body 10. An engagement projection 15A is provided at the center of the engagement recess 15 so that an engagement piece 16 of the lid 11 described later can be fitted therein. The main body 10
The frame engaging portion 17 which can be slightly bent and deformed
The inner frame 3 and the outer frame 4 are retained by being engaged with the engagement protrusions 18 of the outer frame 4.

In FIG. 3, a first combination part 19 is provided on both left and right side walls of the main body part 10. The first combination portion 19 includes two types of uneven portions 3 including a side edge uneven portion 32 provided on the left wall and a central uneven portion 33 provided on the right wall.
2, 33. The side edge uneven portion 32 is provided with two concave portions adjacent to the upper side of the left wall, while the central uneven portion 33 is provided with one concave portion at the center of the right wall. The first combination portion 19 can be fitted into only a first combination receiving portion 21 provided in a frame housing portion 20 of the outer frame 4 described later.

The first combination portion 19 is obtained by exchanging the positions of the side edge uneven portion 32 and the central uneven portion 33, that is, the center wall uneven portion 33 is provided on the right wall, and the side edge uneven portion 3 is provided on the left wall.
2 is a second combination part 27, and the pair of inner frame bodies 3 has at least two parts, one having the first combination part 19 on the outer wall thereof and the other having the second combination part 27. Types are provided.

The lid 11 is connected to the main body 1 via a hinge 12.
0, and an open position (position shown in FIG. 3) for opening the terminal accommodating portions 8, 9 and a closed position for closing the terminal accommodating portions 8, 9 to prevent the terminal fittings 1, 2 from being removed (FIG. 1 or the position shown in FIG. 10). In the lid portion 11, a surface for closing the main body portion 10 (a surface shown in FIG. 3) is provided with the terminal accommodating portions 8,
At a position matching with the position 9, an electric wire holder 22 that comes into contact with the surface of the electric wire 5 is protruded. In FIG. 3, an engagement piece 16 is protruded from a right edge of the lid 11. The engagement piece 16 can be slightly bent and deformed in the left-right direction in the figure, and has an engagement hole 16A in the center thereof.
Is provided (see also FIG. 5), where the engagement protrusion 15 </ b> A of the main body 10 is engaged to thereby form the lid 1.
1 is fixed in the closed position.

At the center of the lid 11, a buttable portion 38 (corresponding to the "receiving portion" in the present invention) having the same shape as the through hole 36 of the main body is provided. In the inner frame 3 shown in FIG. 3, the abuttable portion 38 is formed in a hole shape opened on the front and back of the lid 11, and when the lid 11 closes the main body 10, the abuttable portion 38 is formed in the through hole 36. In alignment, the frame identification portion 37A protruding higher from the back side of the lid portion 11 (the back side of the surface shown in FIG. 3) can be fitted.
Although not shown, the inner frame 3 is prepared with the abuttable portion 38 closed. For this reason, the inner frame 3 provided with the first and second combination portions 19 and 27 is provided as a set in which the abutable portion 38 is opened or closed, and four types of inner frames are provided as a whole. A body 3 is provided.

When the abuttable portion 38 is closed, the frame identifying portion 37A projecting higher is abutted against the abuttable portion 38. Thus, in the present embodiment, the abuttable portion 38 is
Since the difference is whether to open or close the hole provided in the lid 11, only a part of the mold of the inner frame 3 needs to be changed, so that it can be manufactured without major design changes.

The outer frame closing portion 14 is connected to the main body 10 via a hinge 13 and is rotatable about the hinge 13 as a rotation center. As shown in FIG. 1 or FIG. 5, the outer frame closing portion 14 is formed at a position substantially perpendicular to the main body 10, and after the inner frame 3 is assembled to the outer frame 4, the main body 10 is closed. Is rotated to a position where it is substantially flush with. A pair of left and right engagement holes 2
An opening 3 is provided, which is engaged with the closing portion engaging projection 24 of the outer frame 4 to protect the terminal fittings 1 and 2 from the outside.

<Outer Frame> Next, the outer frame 4 will be described with reference to FIGS. The outer frame 4 is integrally formed of resin, and a mating terminal fitting 25 for connecting the terminal fittings 1 and 2 to the outside is insert-molded therein. As shown in FIG. 6, the outer frame 4 is provided with a pair of left and right frame housings 20, and each frame housing 20 has a bolt 6 to which a pair of terminal fittings 1 and 2 can be attached. Is protruding. One end of the mating terminal fitting 25 is connected to the bolt 6 inside the resin, while the other end protrudes outside the outer frame 4.

The left and right wall portions of each frame housing portion 20 are provided with combination receiving portions 21 and 28 capable of receiving only one of the combination portions 19 and 27 of the inner frame 3. In FIG. 6, the first combination receiving portion 21 provided on the left frame housing portion 20 is provided with a side edge projection 29 provided on the left wall.
And a central projection 30 provided on the central wall 31.
The side edge protrusion 29 is provided with two protrusions, and can be assembled with the side edge uneven portion 32 of the inner frame 3.
The central projection 30 is provided with one projection, and can be assembled with the central uneven portion 33 of the inner frame 3. Thus, only the inner frame 3 having the first combination portion 19 can be received in the first combination receiving portion 21.

In the right frame housing portion 20, the positions of the above-mentioned projections 29, 30 are formed in reverse. The center projection 30 is on the left center wall 31, and the side edge projection 29 is on the right. The second combination receiving portion 28 is provided on the wall. Therefore, only the inner frame 3 provided with the second combination portion 27 is received by the second combination receiving portion 28. In this manner, the inner frame 3 can be accommodated at the regular assembling position depending on the positional relationship between the projections 29 and 30.

In each of the frame accommodating portions 20, a fitting concave portion 43 that opens outward is provided at the center of the upper end portion (opening edge portion of the frame accommodating portion 20) in FIG. The fitting recess 43 has a substantially square shape, and can be fitted with frame body identifying portions 37A and 37B of the casing 34 described later. In addition, on the left and right outer walls 41 of the outer frame body 4, an assembling uneven portion 40 is provided. The assembling concave / convex portion 40 is formed symmetrically to the left and right, so that it can be attached to the outer frame housing portion 39 of the casing 34 described later irrespective of the left and right positions.

<Casing> Next, the casing 34 will be described (see FIG. 1). An outer frame housing 39 into which the outer frame 4 can be fitted in a pair on the left and right is provided in a casing 34 formed of resin. Outer frame housing 3
On the left and right outer walls 9, uneven portions 42 into which the assembled uneven portion 40 can be incorporated are provided symmetrically.

A pair of frame identification portions 37A and 37B is provided in each of the outer frame housing portions 39 so as to protrude in a quadrangular prism shape. The cross-sections of the two frame body identification portions 37A and 37B are substantially the same in a substantially square shape, and both can be fitted into the fitting recess 43 of the outer frame body 4. In FIG. 1, a pair of frame identification portions 37B provided in the left outer frame housing portion 39 is formed lower than a pair of frame identification portions 37A provided in the right side. The protruding height of the lower frame identification portion 37B is equal to the height of the outer frame 4 from the bottom surface to the bottom surface of the frame housing portion 20 (the height indicated by “D” in FIG. 8). Or slightly lower. On the other hand, the higher frame identification unit 3
The protruding height of 7A is set higher than the height indicated by reference numeral D and lower than the height of the outer frame 4 (the height indicated by reference numeral F in FIG. 8).

<Operations and Effects of the Embodiment> Next, the operations and effects of the embodiment configured as described above will be described with reference to FIGS.

First, the first and second terminal fittings 1 and 2 are mounted on the first and second terminal receiving portions 8 and 9 of the inner frame 3. In this mounting operation, if the mounting positions of the terminal fittings 1 and 2 are incorrect, the form of the terminal fittings 1 and 2 does not match the shape of the terminal identification portions 8A and 9A. 2 cannot be pushed into the normal position, and erroneous assembly is found.

After the terminal fittings 1 and 2 have been mounted in their proper positions, the lid 11 is rotated to the closed position. Lid part 11
By engaging the engagement piece 16 with the engagement protrusion 15A, the lid 11 and the main body 10 are engaged, and the terminal fittings 1 and 2 are prevented from falling off. At this time, the positions of the through-hole 36 of the main body 10 and the abuttable portion 38 of the lid 11 are aligned.

Next, the pair of inner frames 3 are housed in the frame housing portion 20 of the outer frame 4. During this assembly operation,
Bolts 6 are inserted into bolt through holes 7 of terminal fittings 1 and 2 protruding from inner frame 3. If the positional relationship between the two inner frames 3 is a regular assembling place,
Both the inner frames 3 are accommodated in the outer frames 4 so that the 9, 27 and the combination receiving portions 21, 28 corresponding to the combination portions 19, 27 are aligned (see FIG. 11). At this time, the positions of the through hole 36 of the inner frame 3 and the fitting recess 43 of the outer frame 4 are aligned.

On the other hand, when the mounting position of the inner frame 3 is incorrect (for example, in FIG. 12, the inner frame 3 having the second combination (Showing a case where it is going to be attached to the storage part 20).
Since the concave and convex shapes of the combination receiving portions 21 and 28 do not match with each other, the inner frame 3 cannot be accommodated, and erroneous assembling is found (in FIG. 12, a circle indicated by a symbol “A”). Inside, the central uneven portion 33 and the side edge projection 29 abut each other. Although not shown, the side edge uneven portion 32 and the central projection 30 abut on the center wall 31.) .

When the inner frame members 3 are mounted on the outer frame member 4, nuts (not shown) are attached to the bolts 6, and then the outer frame closing portions 14 protect the terminal fittings 1 and 2. Then, it is assembled to the outer frame 4.

Next, the pair of outer frames 4 is
In the outer frame housing 39. Here, the outer frame 4 and the outer frame housing 3 will be described with reference to FIGS.
9 will be described. In the actual assembling procedure, since the inner frame 3 and the outer frame 4 are assembled to the casing 34 in a combined state, the states shown in FIGS. 13 and 14 do not appear.

In FIG. 13, the outer frame 4 is assembled to an outer frame housing 39 provided with a lower frame identifying portion 37B. At this time, the frame body identification section 37B
Although fitted into the fitting recess 43, its tip is inside the fitting recess 43 and does not protrude toward the frame housing portion 20. For this reason, the low frame identification part 37B
The outer frame housing 39 provided with
The outer frame 4 on which the inner frame 3 is closed or opened can be accommodated.

On the other hand, in FIG. 14, the outer frame 4 is assembled to the outer frame housing 39 provided with the frame identifying portion 37A projecting higher, and the frame identifying portion 37A is fitted into the fitting recess 43. At the same time, the tip portion protrudes to the frame housing portion 20. For this reason, if it is attempted to accommodate the outer frame 4 mounted with the inner frame 3 provided with the closed abuttable portion 38 in the outer frame accommodating portion 39 having the high frame identifying portion 37A, Since the frame body identification portion 37A and the abuttable portion 38 are in contact with each other, the casing 3
The misassembly for No. 4 is found. When the outer frame 4 having the inner frame 3 provided with the open buttable portion 38 is housed in the outer frame housing 39 having the high frame identifying portion 37A, The body identification part 37A is inserted into the through hole 36 of the main body part 10 after penetrating the lid part 11 that opens to the front and back of the inner frame 3.

FIG. 15 shows a state in which both outer frame members 4 are mounted at regular positions with respect to the casing 34. For convenience of illustration, FIG. 15 also shows a state in which only the outer frame 4 is attached to the casing 34. However, in an actual assembling operation, the outer frame 4 is integrated with the inner frame 3. Have been. As described above, according to the present embodiment, when the pair of terminal fittings 1 and 2 are mounted on the inner frame 3, regular terminal fittings are mounted at predetermined positions by the terminal identification portions 8A and 9A. When the inner frame 3 is mounted on the outer frame 4, the regular inner frame is mounted at a predetermined position by the combination portions 19 and 27 and the combination receiving portions 21 and 28. Thus, the terminal fittings 1 and 2 are assembled at the regular assembling positions.

Further, since the inner frame 3 is provided with the lid 11, the terminal fittings 1, 2 are prevented from falling off when the terminal fittings 1, 2 are mounted on the inner frame 3. it can. Further, when the outer frame 4 is mounted on the casing 34, the frame identifying portions 37A and 37B of the casing 34
By identifying the unevenness between the through hole 36 of the inner frame 3 (not the outer frame 4) and the abuttable portion 38,
The outer frame 4 is fitted in a proper place of the casing 34. As described above, since the outer frame 4 is identified between the casing 34 and the inner frame 3, the outer frames 4 have the same form. In other words, if a plurality of types of smaller inner frames 3 are formed, the same type of larger outer frames 4 may be used, so that the cost can be reduced as a whole.

The present invention is not limited to the above-described embodiment. For example, the following ones are also included in the technical scope of the present invention. (1) In the present embodiment, two types of terminal fittings 1 and 2 are accommodated in two sets of the inner frame 3 and are assembled to the outer frame 4. The number of metal fittings, inner frames, and outer frames is not limited to the above, and three or more types of terminal fittings and three or more sets of inner frames may be assembled. (2) In the present embodiment, the combination portions 19 and 27 and the combination receiving portions 21 and 28 are provided symmetrically. However, according to the present invention, it is not necessary to form them symmetrically. The group identification unit may be provided so that the group identification unit can be assembled at the position.

(3) In the present embodiment, the frame identifying section 37
A and B project in a columnar shape having a substantially square cross section. However, according to the present invention, the cross sectional shape does not matter, and it is not necessary to have a columnar shape. (4) In the present embodiment, the columnar frame body identification portions 37A and B are provided so as to project from the casing 34, and the abuttable portion 38 and the through hole 36 are provided on the inner frame body 3. However, according to the invention, ,
The configuration may be reversed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state before an inner frame body, an outer frame body, and a casing to which terminal fittings are attached in a first embodiment.

FIG. 2 is a front view of a terminal fitting.

FIG. 3 is a front view of the inner frame.

FIG. 4 is a side view of the inner frame.

FIG. 5 is a plan view of the inner frame.

FIG. 6 is a front view of the outer frame.

FIG. 7 is a side view of the outer frame body.

FIG. 8 is a plan view of the outer frame body.

FIG. 9 is a front view showing a state before the terminal fitting is attached to the inner frame body and the lid body is closed.

FIG. 10 is a perspective view of an inner frame body to which terminal fittings have been attached before being assembled to an outer frame body.

FIG. 11 is a perspective view when the inner frame is mounted at a regular position with respect to the outer frame.

FIG. 12 is a perspective view when the mounting position is incorrect when the inner frame body is mounted on the outer frame body.

FIG. 13 is a perspective view showing a state in which the outer frame body is assembled to an outer frame body accommodating section provided with a frame body identifying section for projecting lower.

FIG. 14 is a perspective view showing a state where the outer frame body is assembled to an outer frame body accommodating section provided with a frame body identifying section for projecting higher.

FIG. 15 is a front view when a pair of outer frames are assembled to a casing.

FIG. 16 is a diagram of a conventional example in which terminal fittings are assembled to a base.

[Explanation of symbols]

 1, 2, terminal fittings 3, inner frame 4, outer frame 8A, 9A, terminal identification parts 21, 28, combination receiving part (group identification part) 25, mating terminal fitting 34, casing 36, through hole (receiving part) Part) 37: frame identification part 38: abuttable part (receiving part)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Izumi Suzuki 1-14 Nishisuehirocho, Yokkaichi-shi, Mie Sumitomo Wiring Systems, Ltd. (72) Inventor Toshio Asami 1-4-1 Chuo, Wako-shi, Saitama Stock F-term in Honda R & D Co., Ltd. (reference) 5E086 CC47 DD05 DD33 DD49 HH01 HH02 HH20 JJ01 JJ04 JJ11 JJ24 JJ34 JJ36 LL15

Claims (2)

[Claims] 1. A plurality of groups of terminal fittings of a plurality of forms, each of which is formed by assembling the same number of pieces, and a group provided for each group, wherein the arrangement of the terminal fittings in each group is correct. In the case of the arrangement, a plurality of inner frames having a plurality of forms provided with a terminal identification portion that cannot be fitted are provided, and a mating terminal fitting group that can be individually connected to each of the terminal fittings is arranged. A plurality of outer frames formed in a common form, each having a group identification portion provided with a group identification portion that enables fitting when the arrangement of the inner frames is correct and disables fitting when the arrangement is incorrect. A frame, and a casing provided with a frame identification portion that regulates that each of the outer frames in which the inner frame is incorporated is incorrectly arranged, wherein the frame identification portion is With the same number as the outer frame The receiving portion on the other side of the concavo-convex form, which is one side of the concavo-convex form having a different form, and which is individually fitted to each other and cannot be fitted when the combination is different, A structure for preventing erroneous assembling of terminal fittings, which is formed on a frame. 2. The casing is capable of incorporating two of the outer frames in parallel, and has an inner surface on which the frame identification portion formed in a columnar shape with different heights is erected. The outer frame body is formed with an identification portion introduction recess capable of receiving both frame body identification portions toward the inner frame body, and the inner frame body incorporated in each outer frame body includes:
When the arrangement of the outer frame body with respect to the casing is normal, the outer frame body is fitted with the corresponding frame body identification section, and when the arrangement is incorrect, the outer frame body abuts against the non-corresponding frame body identification section. 2. The structure for preventing erroneous assembly of terminal fittings according to claim 1, wherein said receiving portion is provided so as to make fitting impossible.