# Patent

## Title
Connection structure for ground terminal fitting

## Abstract

A connection structure connects a plate-like terminal main body (11) on the ground terminal fitting (10) in surface contact with a grounding member (20) that has female screw holes (41, 42) and a receiving portion (23). A wire connecting portion (12) on the ground terminal fitting (10) is connected to a wire (60). A lock (13) on the terminal main body (11) engages the receiving portion (23) and is on an axis line extension (70) of the wire (60). Mounting holes (151, 152) formed on the terminal main body (11) and aligned with the female screw holes (41, 42) by locking the lock (13) to the receiving portion (23). The ground terminal fitting (10) is connected to the grounding member (20) by screwing bolts (51, 52) inserted through the mounting holes (151, 152) into the female screw holes (41, 42).

## Background
BACKGROUND
1. Field of the Invention
The present invention relates to a connection structure for ground terminal fitting.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 2004-253167 discloses a connection structure for fitting and connecting through holes of a ground terminal to two stud bolts projecting on a ground panel. The connection structure that has stud bolts projecting on the ground panel easily positions the ground terminal with respect to the ground panel. However, positioning the ground terminal with respect to the ground panel is difficult with a connection structure that has a female screw hole provided on a ground panel and a through hole of a ground terminal positioned with respect to the female screw hole.
Consideration has been given to providing a lock on the ground terminal for locking to a receiving portion formed on the ground panel to facilitate positioning the ground terminal. However, this approach presents a new problem of positioning the lock and the receiving portion prior to locking the lock to the receiving portion.
The invention was completed based on the above situation and aims to improve operability.
SUMMARY OF THE INVENTION
The invention relates to a connection structure to connect a plate-like terminal main body on a ground terminal fitting in surface contact with a grounding member. The connection structure includes a female screw hole and a receiving portion formed on the grounding member. A wire connecting portion is formed on the ground terminal fitting and is connected to a wire. A locking portion is formed on the terminal main body on an axis line extension of the wire connected to the wire connecting portion and is configured to be locked to the receiving portion. A mounting hole is formed on the terminal main body and can be aligned with the female screw hole by locking the locking portion to the receiving portion. The ground terminal fitting is connected to the grounding member by inserting a bolt through the mounting hole and screwing the bolt into the female screw hole.
The locking portion is arranged on the extension of the axis line of the wire. Thus, an operator can easily visually grasp a positional relationship of the locking portion and the receiving portion and can easily control the position and movement of the locking portion by gripping the wire. Thus, positioning the mounting hole with respect to the female screw hole for locking is facilitated.
A locking direction of the locking portion to the receiving portion may be substantially parallel to an axial direction of the wire. Thus, an operation of locking the locking portion to the receiving portion is performed easily.
The locking portion and the receiving portion may be capable of coming into contact with each other to prevent following rotation of the terminal main body portion when the bolt is tightened. Accordingly, the locking portion and the receiving portion for positioning the mounting hole with respect to the female screw hole also function to prevent following rotation of the terminal main body portion. Therefore the structure is simplified as compared with the case where both functions are exhibited by separate dedicated parts.
The grounding member may have first and second female screw holes. The terminal main body may be formed with a first mounting hole corresponding to the first female screw hole and a second mounting hole corresponding to the second female screw hole. A difference between inner diameters of the second female screw hole and the second mounting hole may be larger than a difference between inner diameters of the first female screw hole and the first mounting hole. Thus, if the bolt is first tightened to fix the ground terminal fitting to the grounding member at the first female screw hole and the first mounting hole having a smaller inner diameter difference, there is no likelihood that an opening area of the second mounting hole deviates from that of the second female screw hole at the second female screw hole and the second mounting hole having a larger inner diameter difference.
The locking portion and the receiving portion may be capable of contacting each other to prevent following rotation of the terminal main body portion when the bolt is tightened. A distance from the receiving portion to the first female screw hole may be longer than a distance from the receiving portion to the second female screw hole. The technical significance of this configuration is as follows. In the case of tightening the bolt, a moment acting on the receiving portion and the locking portion is suppressed lower as a distance from a center of rotation of the bolt to the receiving portion becomes longer. Thus, the distance from the first female screw hole to be first bolt-fastened to the receiving portion is set longer than the distance from the second female screw hole to be bolt-fastened later to the receiving portion. In this way, loads on the receiving portion and the locking portion can be reduced.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view showing a state where a ground terminal fitting is connected to a grounding member in one embodiment.
FIG. 2 is a section along X-X of FIG. 1.
FIG. 3 is a plan view showing a state where the ground terminal fitting is positioned with respect to the grounding member by locking a locking portion to a receiving portion.
FIG. 4 is a plan view showing a state where a bolt is tightened at a first female screw hole and a first mounting hole from the state of FIG. 3.
FIG. 5 is a plan view of the grounding member.
FIG. 6 is a plan view of the ground terminal fitting.
FIG. 7 is a side view of the ground terminal fitting.



DETAILED DESCRIPTION
A connection structure for a ground terminal fitting is identified by the numeral 10 in FIGS. 1 to 7 and is configured for fixing and electrically conductively connecting the ground terminal fitting 10 in surface contact with a ground contact surface 21 of a grounding member 20 such as a body of a vehicle. Note that, an upper side in FIGS. 1, 3 to 6 is defined as a “front” concerning a front-back direction. Further, a vertical direction is based on FIGS. 2 and 7 and a lateral direction is based on FIGS. 1, 3 to 6.
As shown in FIGS. 2 and 5, the grounding member 20 includes a panel 22 in the form of a flat metal plate. A first metal nut 31 is fixed electrically conductively to the lower surface of the panel 22, such as by welding and a second metal nut 32 is fixed electrically conductively to the lower surface of the panel 22, such as by welding. The upper surface of the panel 22 defines the ground contact surface 21 for electrically conductive connection to the ground terminal fitting 10.
A receiving portion 23 penetrates through the panel 22 from the upper to lower surfaces of the panel 22 and has a substantially rectangular opening in a plan view thereof. A front edge of the opening edge of the receiving portion 23 defines a stopper 24. Areas of the ground contact surface 21 of the panel 22 near opposite left and right opening edges of the receiving portion 23 function as receiving surfaces 25. The receiving portion 23 has both a positioning function of determining the position of the ground terminal fitting 10 on the upper surface of the panel 22 in a horizontal direction and a rotation stopping function of preventing following rotation of the ground terminal fitting 10 when bolts 51, 52 are tightened.
The second nut 32 is arranged at a position behind and at a distance from the receiving portion 23. That is, a straight line connecting the second nut 32 and the receiving portion 23 extends in the front-back direction. The first nut 31 is arranged behind the receiving portion 23 and to the right of the second nut 32. A straight line connecting the first and second nuts 31, 32 extends in the lateral direction and is perpendicular to the straight line that connects the second nut 32 and the receiving portion 23. Thus, the receiving portion 23, the first nut 31 and the second nut 32 constitute vertices of a right-angled triangle.
The first nut 31 is formed with a first female screw hole 41, and the panel 22 is formed with a circular first through hole 261 arranged coaxially with the first female screw hole 41. The first through hole 261 has a slightly larger inner diameter than the first female screw hole 41. The second nut 32 is formed with a second female screw hole 42 having an inner diameter equal to that of the first female screw hole 41. The panel 22 also is formed with a circular second through hole 262 arranged coaxially with the second female screw hole 42. The second through hole 262 has a slightly larger inner diameter than the second female screw hole 42.
The ground terminal fitting 10 is formed by bending a metal plate material punched out into a predetermined shape. As shown in FIGS. 6 and 7, the ground terminal fitting 10 is configured by integrally forming a terminal main body 11 in the form of a flat plate and a wire connecting portion 12 in the form of an open barrel.
The terminal main body 11 has a plan shape obtained by rotating a T shape counterclockwise by 90°. A lock 13 is cantilevered forward from the front end of the terminal main body 11. A width of the lock 13 in the lateral direction is constant over the entire length and is slightly smaller than a width of an opening area of the receiving portion 23. The lock 13 is bent in a stepped manner. Specifically, the lock 13 has a base 13A flush with the terminal main body 11, a step 13B extending down from the projecting end of the base 13A and a tip 13C extending forward from the lower end of the step 13B. The lock 13 is locked by obliquely inserting the tip 13C and the step 13B into the receiving portion 23 from an upper-rear side.
The width of the lock 13 is smaller than the width of an upper end part of the terminal main body 11 and two butting portions 14 are formed at opposite left and right sides of the lock 13 due to this dimensional difference. The butting portions 14 protrude bilaterally symmetrically out in a width direction from left and right edges 13D of the lock 13 and are continuous and flush with the front end part of the terminal main body 11. Further, the front end edges of the butting portions 14 are located on the same straight line to be juxtaposed in the lateral direction. In a state where the lock 13 is locked to the receiving portion 23, the front end edges of the butting portions 14 are laid on the left and right receiving surfaces 25.
A circular first mounting hole 151 penetrates through the terminal main body 11 and registers with the first female screw hole 41 when the lock 13 is locked to the receiving portion 23. An inner diameter of the first mounting hole 151 is slightly larger than inner diameters of the first through hole 261 and the first female screw hole 41. The first bolt 51 can be inserted through the first mounting hole 151 and the first through hole 261 from above the ground terminal fitting 10 and screwed into the first female screw hole 41 when the first mounting hole 151 registers with the first female screw hole 41.
Similarly, a circular second mounting hole 152 penetrates through the terminal main body 11 at a position corresponding to the second female screw hole 42 when the lock 13 is locked to the receiving portion 23. An inner diameter of the second mounting hole 152 is larger than inner diameters of the second through hole 262 and the second female screw hole 42. Thus, the second bolt 52 can be inserted through the second mounting hole 152 and the second through hole 262 from above the ground terminal fitting 10 and screwed into the second female screw hole 42 when the second mounting hole 152 registers with the second female screw hole 42. The second bolt 52 has the same size and shape as the first bolt 51.
The lock 13 is locked to the receiving portion 23 as a first step for mounting the ground terminal fitting 10 on the grounding member 20. Subsequently, the first bolt 51 is screwed and tightened into the first female screw hole 41 and the first mounting hole 151 and, then, the second bolt 52 is screwed and tightened into the second female screw hole 42 and the second mounting hole 152. The inner diameter of the first mounting hole 151 is smaller than the opening area of the second mounting hole 152. Thus, a difference between the inner diameters of the first female screw hole 41 and the first mounting hole 151 to be first bolt-fastened is smaller than a difference between the inner diameters of the second female screw hole 42 and the second mounting hole 152 to be bolt-fastened later.
The lock 13, the first mounting hole 151 and the second mounting hole 152 of the ground terminal fitting 10 are arranged to correspond to the receiving portion 23, the first female screw hole 41 and the second female screw hole 42 of the grounding member 20. Accordingly, the first mounting hole 151, the second mounting hole 152 and the lock 13 are arranged to constitute vertices of a right-angled triangle. A distance from the first mounting hole 151 to be first bolt-fastened to the lock 13 (i.e. distance from the first female screw hole 41 to the receiving portion 23) exceeds a distance from the second mounting hole 152 to be bolt-fastened later to the lock 13 (i.e. distance from the second female screw hole 42 to the receiving portion 23).
The wire connecting portion 12 has a wire barrel 12A and an insulation barrel 12B located behind the wire barrel 12A. The wire barrel 12A and the insulation barrel 12B are of known form. A conductor 62 exposed by removing an insulation coating 61 of an end part of a wire 60 is fixed electrically conductively to the wire barrel 12A. A front end part of the wire 60 where the insulation coating 61 is not removed is fixed to the insulation barrel 12B.
The wire connecting portion 12 has a long narrow base plate 12C. The front end of the base plate 12C is continuous and substantially flush with a rear part of the terminal main body 11. An axis line of the wire 60 fixed to the wire connecting portion 12 extends in the front-back direction. The locking portion 13 is arranged before the wire connecting portion 12 and on an axis line extension line 70 of the wire 60. Similarly, the second mounting hole 152 is arranged between the wire connecting portion 12 and locking portion 13 on the axis line extension line 70 of the wire 60. On the other hand, the first mounting hole 151 is at a position deviated rightward from the axis line extension line 70 of the wire 60. Further, an inserting direction (locking direction) of the locking portion 13 into the receiving portion 23 is substantially parallel to an axis line extension line 70) of the wire 60.
In mounting the ground terminal fitting 10 on the grounding member 20, the terminal main body 11 first is positioned with respect to the ground contact surface 21. At this time, an operator grips a part of the wire 60 near the wire connecting portion 12 with the left hand and controls the position of the lock 13 with respect to the receiving portion 23 while visually confirming the positions of the lock 13 and the receiving portion 23. The locking portion 13 then is inserted into the receiving portion 23 from behind and the step 13B is caused to face the stopper 24. The lateral position of the terminal main body 11 then is adjusted with the receiving portion 23 and the lock 13 as a support so that the first mounting hole 151 and the first female screw hole 41 are aligned coaxially. In this way, the second mounting hole 152 is aligned with the second female screw hole 42 and the terminal main body 11 is positioned with respect to the ground contact surface 21.
The operator then inserts and lightly screws the first bolt 51 into the first mounting hole 151 with the right hand and tightens the first bolt 51 by operating a tool (not shown) with the right hand while gripping the wire 60 with the left hand. At this time, a clockwise rotational force about the first bolt 51 is applied to the terminal main body portion 11. However, the step 13B of the lock 13 is in contact with the stopper 24 of the receiving portion 23 in a clockwise direction. Thus, a following rotation of the terminal main body portion 11 is prevented. In this way, the second mounting hole 152 is held aligned with the second female screw hole 42.
The second bolt 52 then is inserted through the second mounting hole 152, screwed into the second female screw hole 42 and tightened using the tool. At this point, the terminal main body 11 is fixed to the ground contact surface 21 by the first bolt 51 and following rotation of the terminal main body portion 11 is prevented by the first bolt 51 engaged in the first female screw hole 41 and the side edges 13D of the lock 13 caught by the opening edge of the receiving portion 23. An operation of connecting the ground terminal fitting 10 to the grounding member 20 is completed after tightening the second bolt 52.
The connection structure for the ground terminal fitting 10 of this embodiment connects the plate-like terminal main body 11 provided on the ground terminal fitting 10 in surface contact with the grounding member 20. The ground terminal fitting 10 is formed with the wire connecting portion 12 and the lock 13. The lock 13 is arranged on the axis line extension line 70 of the wire 60 connected to the wire connecting portion 12, and is locked to the receiving portion 23 of the grounding member 20. When the lock 13 is locked to the receiving portion 23, the first and second mounting holes 151, 152 formed on the terminal main body 11 of the ground terminal fitting 10 are aligned respectively with the first and second female screw holes 41, 42 of the grounding member 20.
The lock 13 is arranged on the axis line extension 70 of the wire 60. Thus, the operator can easily visually determine a positional relationship of the lock 13 and the receiving portion 23 and can easily control the position and movement of the lock 13 by gripping the wire 60. Thus, operability in positioning the mounting holes with respect to the female screw holes for locking is good. In addition, since the inserting direction of the lock 13 into the receiving portion 23 is substantially parallel to the axial direction of the wire 60, locking the lock 13 to the receiving portion 23 is performed more easily.
Further, the step 13B of the lock 13 and the stopper 24 of the receiving portion 23 come into contact with each other to prevent following rotation of the terminal main body portion 11 when the first bolt 51 is tightened. Since the lock 13 and the receiving portion 23 for positioning the mounting holes with respect to the female screw holes also function to prevent following rotation of the terminal main body 11, the structure is simplified as compared with the case where both functions are exhibited by separate dedicated parts.
The grounding member 20 is formed with the first and second female screw holes 41, 42, the terminal main body 11 is formed with the first mounting hole 151 corresponding to the first female screw hole 41 and the second mounting hole 152 corresponding to the second female screw hole 42, and the difference between the inner diameters of the second female screw hole 42 and the second mounting hole 152 is larger than the difference between the inner diameters of the first female screw hole 41 and the first mounting hole 151. The bolt first is tightened at the first female screw hole 41 and the first mounting hole 151 having a smaller inner diameter difference to fix the ground terminal fitting 10 to the grounding member 20. Thus, there is no likelihood that the opening area of the second mounting hole 152 deviates from that of the second female screw hole 42 at the second female screw hole 42 and the second mounting hole 152 having a larger inner diameter difference.
The distance from the receiving portion 23 to the first female screw hole 41 (i.e. distance from the lock 13 to the first mounting hole 151) exceeds the distance from the receiving portion 23 to the second female screw hole 42 (i.e. distance from the locking portion 13 to the second mounting hole 152). The technical significance of this configuration is as follows. In the case of tightening the bolt, a moment acting on the receiving portion 23 and the lock 13 is suppressed lower as a distance from a center of rotation of the bolt to the receiving portion 23 becomes longer. Thus, the distance from the first female screw hole 41 to be bolt-fastened first to the receiving portion 23 exceeds the distance from the second female screw hole 42 to be bolt-fastened later to the receiving portion 23. In this way, loads on the receiving portion 23 and the lock 13 can be reduced.
The receiving portion 23 on the grounding member 20 is in the form of a through hole and the lock 13 formed on the ground terminal fitting 10 is cantilevered and includes the step 13B. The lock 13 is locked to the receiving portion 23 in a state where the step 13B can come into contact with the stopper 24 of the receiving portion 23. In tightening the first bolt 51 at the first mounting hole 151 and the first female screw hole 41, a rotational force in a direction to bring the step 13B into contact with the stopper 24 is applied to the terminal main body 11. In this case, if the rotational force acting on the terminal main body portion 11 is strong, the step 13B may be separated from the stopper 24 while the terminal main body 11 rotates following the first bolt 51, and the lock 13 may improperly sink deep into the receiving portion 23. However, the terminal main body 11 of the invention is provided with the butting portions 14 for preventing the following rotation of the terminal main body portion 11. The butting portions 14 protrude from the side edges 13D of the locking portion 13 and contact the receiving surfaces 25, which are areas of the ground contact surface 21 near the opening edge of the receiving portion 23, when the first bolt 51 is tightened. In addition, since the pair of butting portions 14 are provided at the opposite sides of the lock 13, they stably contact with the receiving surfaces 25. This contact action prevents the lock 13 from improperly sinking into the receiving portion 23 and the following rotation of the terminal main body 11. In this way, a displacement of the second mounting hole 152 with respect to the second female screw hole 42 is also prevented.
The invention is not limited to the above described and illustrated embodiment. For example, the following embodiments are also included in the scope of the present invention.
Although the inserting direction of the locking portion into the receiving portion is substantially parallel to the axial direction of the wire in the above embodiment, it may be a direction intersecting with the axial direction of the wire.
Although the lock is formed on the outer peripheral edge part of the terminal main body portion in the above embodiment, it may be formed by cutting and bending or striking a part of the terminal main body portion.
Although the lock is bent in the stepped manner (step-like manner) with respect to the terminal main body portion in the above embodiment, it may be flush with the terminal main body portion.
Although two mounting holes and two female screw holes are provided in the above embodiment, one, three or more mounting holes and one, three or more female screw holes may be provided.
Although the receiving portion is in the form of a through hole in the above embodiment, it may be in the form of a dead-end recess on the grounding member or in the form of a projection projecting from the grounding member and formed such as by cutting and bending.
Although the female screw holes are formed on the nuts fixed to the under surface of the panel constituting the ground contact surface of the grounding member in the above embodiment, they may be directly formed on a member constituting the ground contact surface of the grounding member.
Although the first mounting hole, the second mounting hole and the lock (i.e. the first female screw hole, the second female screw hole and the receiving portion) are arranged to constitute the vertices of the triangle in the above embodiment, they may be arranged side by side on one straight line.
Although the distance from the first mounting hole to be first bolt-fastened to the lock (i.e. distance from the first female screw hole to the receiving portion) is set longer than that from the second mounting hole to be bolt-fastened later to the lock (i.e. distance from the second female screw hole to the receiving portion) in the above embodiment, the distance from the first mounting hole to the lock may be equal to or shorter than that from the second mounting hole to the lock.
Although the first mounting hole is arranged at the position deviated from the line connecting the lock and the wire connecting portion (axis line extension line of the wire) in the above embodiment, it may be arranged on the line connecting the lock and the wire connecting portion.
Although the second mounting hole is arranged at the position on the line connecting the lock and the wire connecting portion (axis line extension line of the wire) in the above embodiment, it may be arranged at a position deviated from the line connecting the locking portion and the wire connecting portion.
Although the difference between the inner diameters of the first female screw hole to be first bolt-fastened and the first mounting hole is set smaller than that between the inner diameters of the second female screw hole to be bolt-fastened later and the second mounting hole in the above embodiment, it may be equal to or larger than the difference between the inner diameters of the second female screw hole and the second mounting hole.
Although the inner diameter of the first mounting hole to be first bolt-fastened is substantially equal to that of the first female screw hole in the above embodiment, the inner diameter (opening area) of the first mounting hole may be set larger than that (opening area) of the first female screw hole.
Although the inner diameter of the second mounting hole to be bolt-fastened later is set larger than that (opening area) of the second female screw hole in the above embodiment, the inner diameter of the second mounting hole may be substantially equal to that of the second female screw hole.
Although the inner diameters of the first and second female screw holes are set equal in the above embodiment, they may be different.
Although the inner diameter of the first mounting hole is set smaller than that (opening area) of the second mounting hole in the above embodiment, it may be equal to or larger than the inner diameter of the second mounting hole.
LIST OF REFERENCE SIGNS


    10 . . . ground terminal fitting
    11 . . . terminal main body
    12 . . . wire connecting portion
    13 . . . lock
    151 . . . first mounting hole
    152 . . . second mounting hole
    20 . . . grounding member
    23 . . . receiving portion
    41 . . . first female screw hole
    42 . . . second female screw hole
    51 . . . first bolt
    52 . . . second bolt
    60 . . . wire
    70 . . . axis line extension line

## Claims

1. A connection structure for connecting a plate-like terminal main body provided on a ground terminal fitting in surface contact with a grounding member, comprising:
first and second female screw holes formed on the grounding member;
a receiving portion formed on the grounding member;
a wire connecting portion formed on the ground terminal fitting and connected to a wire;
a lock formed on the terminal main body to be able to be locked to the receiving portion and arranged on an axis line extension line of the wire connected to the wire connecting portion, a locking direction of the lock to the receiving portion being substantially parallel to an axial direction of the wire;
a first mounting hole formed on the terminal main body at a position to be aligned with the first female screw hole when the lock is locked to the receiving portion; and
a second mounting hole formed on the terminal main body at a position to be aligned with the second female screw hole when the lock is locked to the receiving portion;
the ground terminal fitting being connected to the grounding member by screwing a first bolt inserted through the first mounting hole into the first female screw hole and screwing a second bolt inserted through the second mounting hole into the second female screw hole, and wherein,
the lock and the receiving portion are capable of coming into contact with each other to prevent following rotation of the terminal main body when the first bolt is tightened, and
a difference between inner diameters of the second female screw hole and the second mounting hole exceeds a difference between inner diameters of the first female screw hole and the first mounting hole.

2. The connection structure of claim 1, wherein the first mounting hole is offset from the axis line extension line.

3. The connection structure of claim 1, wherein the terminal main body is substantially planar at all locations spaced from the lock.

4. The connection structure of claim 1, wherein the lock is bent about at least one bend line extending substantially perpendicular to the axis line extension line.

5. The connection structure of claim 1, wherein:
the lock and the receiving portion contact each other to prevent following rotation of the terminal main body when the first bolt is tightened; and
a distance from the receiving portion to the first female screw hole exceeds a distance from the receiving portion to the second female screw hole.

6. The connection structure of claim 1, wherein the second mounting hole is on the axis line extension line.