JPS6226937Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a clamping device for cables in electrical connectors and the like.

2. Description of the Related Art In general, electrical connectors and the like are provided with a cable clamp device to prevent the cable from coming out of the connector. For example, in a conventional electrical connector for a ribbon cable, as shown in FIG. 1 of the accompanying drawings, which are partially cut away, clamp protrusions 3 and 4 are integrally formed on the inner walls of a pair of plastic cases 1 and 2, respectively. The ribbon cable 5 formed in advance and connected to each contact (not shown) arranged in the contact arrangement part 6 of the electrical connector is wound between the clamp protrusions 3 and 4, and the case 1 is closed. Clamping of the cable 5 was effected by tightening the cables 5 and 2 against each other.

Problems to be Solved by the Invention However, in this method of clamping by tightening the plastic cases 1 and 2 (including the clamping protrusions 3 and 4) themselves, as the width of the cable to be clamped increases, As shown exaggerated in the rear view of Figure 2, the plastic case 1
The center portion of cable 2 inevitably swells, and the clamp holding force is concentrated only on both sides, resulting in a decrease in the holding force for the center of the cable. In Figure 2, W is insulation case 1
and 2, where W′ is the normal thickness of cable 5
It shows the thickness of the bulge in the center of plastic cases 1 and 2 when they are clamped. In order to eliminate this kind of bulge in the center of the case as much as possible, conventional methods increase the thickness of the plastic case to provide the necessary strength for the clamp part and increase the tightening force at both ends of the case. In this case, strong force or force may be applied to both ends of the cable, which may crush the cable and cause it to break, resulting in accidents such as disconnection or shorting.Also, because the external shape of the electrical connector increases the thickness of the case, As a result, it becomes difficult to increase the packaging density.
Furthermore, even if the case thickness is increased to increase the tightening force at both ends of the case, as mentioned above, as the cable width increases, the center of the case tends to bulge, and the cable retention force is reduced at both sides. This tends to reduce the holding power of the cable in the center. A decrease in the holding force at the center of the cable will cause the cable inside the case to be displaced from the clamp due to the tensile force applied to the cable from the outside, resulting in inconveniences such as poor contact between the cable core and the contactor and breakage of the core wire. It will increase the risk.

Here, let's consider why plastic cases tend to bulge in the center like this. With the cable 5 sandwiched between the plastic cases 1 and 2 shown in FIG. 1 and FIG.
When the plastic cases 1 and 2 are not inflated, the clamping protrusions 3 and 4 apply a uniform clamping force to the cable 5 along its width. It turns out. A uniformly distributed load is applied to the clamping protrusions 3 and 4 in the outward direction along the width thereof as a reaction force of the clamping force. In this state, each of the plastic cases 1 and 2 has become a support beam at both ends that is receiving an evenly distributed load with support points at the application points of the aforementioned clamping force, that is, points near the outside of both edges of the cable 5. It can be said that there are. Therefore, the deflection δ at the center of the support beam at both ends, which is subjected to an evenly distributed load, is expressed by the following equation.

δ=KL ⁴ P/EI...(1) Here, K is a constant, L is the span of the support beam,
P is a uniformly distributed load, E is Young's modulus of the material of the support beam, and I is the moment of inertia of the support beam.
As is clear from equation (1), the amount of deflection δ at the center of the beam supported at both ends, which receives a uniformly distributed load, is the span L
The larger the distributed load P is, the larger it becomes, and the larger the Young's modulus E and moment of inertia I of the material of the support beam, the smaller it can be. Place this in plastic case 1
and 2, the width of the case corresponds to the span L, the reaction force of the clamping force applied to the cable 5 corresponds to the uniformly distributed load P, and the Young's modulus of the plastic forming the case corresponds to the Young's modulus E.
The moment of inertia of area determined by the cross-sectional shape of the case including the clamping protrusion 3 or 4 corresponds to the moment of inertia of area I. Therefore, the deflection (amount of bulge) at the center of cases 1 and 2 increases as the widths of cases 1 and 2 increase, and as the clamping force applied to cable 5 increases. It can be seen that the smaller the Young's modulus of the plastic material, and the smaller the moment of inertia of the case, the larger it becomes.
Here, if the width of the case is constant, the amount of deflection (amount of bulge) at the center of each case is
It is proportional to the clamping force applied to the case material and inversely proportional to the Young's modulus of the case material and the moment of inertia of the case. Generally, the clamp protrusion 3,
If a case having a shape like 4 is provided, the moment of inertia of the case will certainly increase, and the amount of bulge in the center of the case can be suppressed. However, if the Young's modulus of the case material is small, the amount of bulge at the center of the case inevitably increases as the clamping force of the cable 5 increases. The Young's modulus of the plastic material forming Cases 1 and 2 is 100% of the Young's modulus of metal.
Since it is about 1/2 as small, even if we try to increase the moment of inertia by providing the clamping protrusions 3 and 4 on the case, the width of the case will become wider and the cable 5 will not be clamped. If it is necessary to increase the force, it is difficult to suppress the amount of bulge at the center of cases 1 and 2. This means that even if the clamping protrusions 3 and 4 are integrally formed in the conventional plastic case described above,
This is thought to be the reason why the center of the case had swelled up a lot.

An object of the present invention is to eliminate the above-mentioned drawbacks of the clamping device and to provide a cable clamping device that is small in size and has a simple structure that provides sufficient clamping force.

Means for Solving the Problems The cable clamping device according to the present invention includes a pair of plastic cases that are considerably wide in comparison to their thickness, and a pair of cases that are connected at both edges in the width direction of the cases. It includes a clamping member for clamping each other and a pair of flat clamp metal plates, each of the clamp metal plates being formed between the clamping positions on the inner wall of each corresponding case. The cable is installed in the holding part, and the cable is clamped between the top surfaces of the clamp metal plates in the height direction.

Embodiments Next, the present invention will be described in more detail with regard to embodiments of the present invention based on FIGS. 3 to 7 of the accompanying drawings.

FIG. 3 is a front view of a plug case of an electrical connector for a ribbon cable to which the present invention is applied, and FIG. 4 is a plan view thereof, also showing the clamped cable. This plug case 10 is
A pair of plastic cases 11 and 12 are provided which are wide compared to their thickness when combined with each other. The cases 11 and 12 are tightened at both ends in the width direction with tightening screws 13 and 14. Each case 11 and 12
As shown in the cross-sectional view of Fig. 5, the inner wall of the
Holding protrusions 16 for holding flat clamp metal plates 17 and 18 are each integrally formed. The clamp metal plates 17 and 18 are
It is an elongated piece having a thickness that is weakly press-fitted between the holding projections 16 and a length approximately equal to the width of the cable to be clamped. The height of the clamp metal plates 17 and 18 is determined in the horizontal direction of the metal plates 17 and 18 when the cases 11 and 12 are assembled between the holding protrusions 16, as shown in FIG. The selection is such that the cable 5 to be clamped is gripped between the tips and a sufficient clamping force is selected.

Next, an embodiment of a structure suitable for installing a clamp metal plate will be described with reference to FIGS. 6 and 7. FIG. 6 shows another embodiment of a plastic case corresponding to the plastic case 11 or 12 in the plug case of FIGS. 3 to 5 in an exploded perspective view. This plastic case 21 has an accommodating frame 26 integrally formed on its inner wall for accommodating a clamp metal plate 27. Posts 25 for passing tightening screws are also integrally formed at both ends of the housing frame 26. Figure 7 shows the storage frame 2 of the case in Figure 6.
As shown in FIG. 7, ribs 26A, 26B, 26C, 26D, 26 are provided at predetermined intervals on the inner wall of the housing frame 26.
E, 26F is formed. What should be noted here is that the ribs 26A, 26C, 26D and 26
The protruding heights of F are equal, but the ribs 26B and 26
The protrusion height of E is different from the others, and rib 2
6B is lower than the others, and rib 26E is higher than the others. Therefore, as shown in FIG.
If the metal plate 27 is installed in the housing frame 26 so as to be curved in the direction shown in FIG.

Further, contrary to this embodiment, the protruding heights of the ribs provided on the storage frame are all the same, and the clamp metal plate 27 is formed in advance into a V-shaped curve. effect can be achieved. Alternatively, the clamp metal plate may be embedded in the plastic case in advance by molding.

Furthermore, if you prepare two or more types of clamp metal plates with different heights, you can easily make the same plug case applicable to two or more different types of cables by simply replacing these metal plates. can.

Finally, the operation of the cable clamp device according to the present invention will be explained. Also in the cable clamp device of the present invention, when the cable 5 is sandwiched between the cases 11 and 12 and the cases 11 and 12 are tightened near the outside of both ends of the cable 5, that is, the tightening screws 13 and 14 are used. When tightening, clamp metal plates 17 and 1
A clamping force is applied to the cable 5 at 8. Therefore, the clamp metal plates 17 and 18
In addition, the reaction force of the clamping force is applied to the cases 11 and 12 as a uniformly distributed load. In this state, the combination of the case 11 and the clamp metal plate 17 and the case 12 are similar to those described in the case of the conventional plastic case.
Each combination of the clamp metal plate 18 and the clamp metal plate 18 behaves as a support beam at both ends receiving an evenly distributed load. Therefore, the amount of deflection (amount of bulge) δ at the center of each combination is expressed by the same equation as the above equation (1). Moment of inertia I of each combination
is the same as in the case of the conventional plastic cases 1 and 2 described above, but the Young's modulus E of the material of each combination body 11, 17 and 12, 18 in the present invention is However, each combination 11 in the present invention is larger than the conventional one made entirely of plastic (the Young's modulus of metal is about 100 times larger than that of plastic).
The amount of deflection (bulging amount) δ of the center portions of 17, 12, and 18 is extremely small compared to the case of a conventional plastic case. Therefore, according to the above-described configuration of the present invention, even if the width of the case is considerably wide, the presence of the clamp metal plate prevents the central part of the case from bulging even if the tightening at both ends of the case is increased. Therefore, the clamping force at both ends is always evenly distributed over the entire clamp via the clamp metal plate, and sufficient clamping force is always distributed equally over the entire clamp width as shown by arrow P in Fig. 8. It will be done.

Effects of the Invention As mentioned above, the above-described structure of the present invention has the following special effects compared to the conventional plastic case.

(1) A very simple and inexpensive clamp metal plate,
Since the clamp metal plate is installed in the holding part formed between the cable clamping positions inside the plastic case, the clamp metal plate is
As shown in , sufficient clamping force can be obtained evenly distributed over the entire cable width. As a result, even if cable tension is applied from the outside,
It can withstand sufficient strength and does not apply tensile force to the connection between the cable core and the contact, and furthermore, since the cable clamp section is clamped evenly, the core wire There will be no damage caused by this.

(2) Since the cable can obtain sufficient clamping force evenly distributed over the entire cable width, there is no need to increase the wall thickness toward the outside of the case, and there is no need to increase the external dimensions of the entire case. It becomes possible to provide a case. Furthermore, since the wall thickness of the case can be made thinner, the overall weight of the case can also be reduced.
Material and processing costs will also be lower.

(3) In conventional plastic cases, the thickness of the protrusion for clamping is increased in order to increase the strength of that part, which results in an imbalance in the thickness of the entire case. After processing, there is a risk that distortion may occur in various parts of the case, and if the case is strained, the cable cannot be tightened. The thickness can be made almost uniform, and no distortion occurs in the case.

(4) Unlike conventional plastic cases, the center part will not bulge or both edges of the cable will be crushed by unreasonably large clamping force, resulting in damage to both edges of the cable.
Stable quality and improved reliability.

[Brief explanation of the drawing]

FIG. 1 of the accompanying drawings is a partially cutaway perspective view showing an example of a conventional ribbon cable electrical connector, and FIG.
3 is a front view of the plug case of the electrical connector for ribbon cable to which the present invention is applied; FIG.
The figure is a plan view of the case in Figure 3, and Figure 5 is a plan view of the case in Figure 3.
FIG. 6 is an exploded parts arrangement perspective view showing another embodiment of the plastic case according to the present invention, and FIG. 7 is a portion of the housing frame of the plastic case shown in FIG. 6. FIG. 8 is a partially enlarged view showing the state in which the cable is clamped by the clamp metal plate. 5... Ribbon cable, 10... Plug case, 11, 12... Plastic case, 1
3, 14... Tightening screw, 16... Holding protrusion,
17, 18...Clamp metal plate, 21...Plastic case, 25...Post, 26...Accommodation frame, 26A, 26B, 26C, 26D, 26E,
26F...Rib, 27...Clamp metal plate.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A pair of plastic cases that are considerably wide compared to their thickness, and a device for tightening the pair of cases against each other at both edges in the width direction of the cases. A clamping member and a pair of flat clamp metal plates are provided, each of the clamp metal plates being installed in a holding portion formed between the clamping positions on the inner wall of each corresponding case, A cable clamp device characterized in that the cable is clamped between the top surfaces of the clamp metal plates in the height direction. (2) The cable clamp device according to claim (1), wherein the clamp metal plate is detachably attached to the holding portion. (3) The cable clamp device according to claim (1), wherein the clamp metal plate is embedded in the holding portion.