JPH06185505A - Earth clamp - Google Patents

Abstract

PURPOSE:To provide an earth clamp wherein a single product can be fitted coping with a cable of different diameters by improving workability at a low cost and can be easily fitted and removed by a single operation even without parts and tools CONSTITUTION:An earth clamp 1 is constituted of a clamp fixing part 18 comprising a cable fixing part 2 having a wave-shaped circular arc-shaped extending/contracting part, U-shaped part 16 set up in both end parts of the cable fixing part and a pressing plate 15 having a pawl (protrusion) 3 in the outside and a stopper 17 in the inside. Mounting holes 7 in two parts and a protrusive part 8 are provided in a chassis of mounting the earth clamp 1. Since spring action is provided by forming the cable fixing part of the earth clamp into a wave-shaped sectional shape, force of tightening a cable 4 is generated, and only the earth clamp 1 in size of single kind can correspond relating to the cable of various different diameters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cable fixing cable.
More particularly, the present invention relates to a one-touch type earth clamp in which grounding (contact) of a grounding portion of a cable to a chassis is reliable and a fixing screw is unnecessary.

[0002]

2. Description of the Related Art A conventional technique for an earth clamp will be described with reference to FIGS. In electronic equipment such as a computer system, for example, a central processing unit (CP
FIG. 7 shows an example of the interface cable for external extraction when the signal from (U) or the like is extracted to the outside. As shown in FIG. 7, in the interface cable 4 for external extraction, a plurality of core wires 14 in which signal transmission wires are coated with resin are wrapped with an insulating coating 13 made of resin or the like, and a metal is provided on the outside thereof. The grounding coating 5 is made of metal, and an insulating outer coating 9 is provided on the outside of the grounding coating 5 for the purpose of protecting the cable. With the structure having such an outer coating 9,
The cable 4 that goes out of the chassis is protected even if a force is applied from the outside. Conventionally, when the interface cable 4 is put out of the chassis 6,
In a state where the outer coating 9 of the cable 4 is peeled off and the ground coating 5 is exposed, the ground coating 5 is fixed on the outer periphery by the metal-made arcuate cable fixing portion 22 as shown in FIG. 5, and the flat clamp fixing portion is formed. The screw 10 is inserted into the hole 12 and fastened to the chassis 6. This allows the cable
The electrical continuity between the cover 5 and the chassis 6 is secured.

The reason for grounding the ground coating 5 of the cable 4 on the chassis 6 will be described below. External device and main unit CPU
When exchanging signals between the cables, the cable core wire 14
Bit information flows at high speed. At this time, an electromagnetic wave is emitted from the core wire 14, but if the earth coating 5 outside the core wire 14 has the same potential as the ground, this electromagnetic wave is not emitted to the outside. Further, the same blocking effect can be obtained against electromagnetic waves coming from other equipment cables, etc., and the internal core wire 1
It is possible to prevent electromagnetic interference from the outside without reaching 4. Therefore, it is necessary to short-circuit the ground coating 5 between the external device and the CPU and ground it. Since the ground of these interface cables 4 is necessary for the external extraction cable, and the external extraction cable is required to withstand a larger tensile force than the inside of the device, conventionally, the screw fastening as described above is generally performed. It was Incidentally, JP-A-3-254199
The publication discloses an improved cable fixing device which is not an earth clamp but is fastened with a screw.

[0004]

The above-mentioned conventional earth clamp and the one disclosed in Japanese Patent Laid-Open No. 3-254199 have the following three problems. 1. Many man-hours are required. The reason is that when installing,
As shown in FIG. 8, (1) Once, expand the metal arc-shaped cable fixing part (a) as shown in (b). (2) Wrap around the cable cover 5 and restore the original shape as shown in (c). (3) Fix with screws (d). This is because the three-step operation is required. further,
When tightening the screws, match the styling of the cable with the
It is necessary to match the mounting direction of the scrump,
This leads to an increase in work man-hours.

2. The purchase price is relatively high, and the management man-hours increase. The reason is that in the above-mentioned conventional earth clamp, the cable fixing portion needs to be brought into close contact with the ground covering portion. It is necessary to prepare an earth clamp, and for that purpose it is necessary to serialize the earth clamp for each size, which reduces the use (purchase amount) for each size and increases the unit price. is there. In addition, it is necessary to manage parts and confirm application with the cable size for each size clamp. 3. As can be seen from the above-mentioned fastening process, screws for fastening parts and drivers for fastening tools are required in addition to the earth clamp body. Therefore, an object of the present invention is to solve the above-mentioned problems, that is, the workability is good, the cost is low, and a single piece can be adapted and attached to cables of different diameters, and there are no parts or tools other than the main body. Another object is to provide an easily attachable / detachable earth clamp.

[0006]

In order to achieve the above object, the earth clamp of the present invention has a metal coating in which the outer circumferences of a plurality of core wires bundled in a circular cross section are covered with a conductive metal. In an earth clamp for grounding a cable for contact-fixing a cable to a chassis, the earth clamp includes an arc-shaped cable fixing portion formed in a corrugated cross-sectional shape and a pressing plate in which both ends thereof are bent inward in a U shape. It is composed of a clamp fixing portion having a protrusion (projection) on the outside.

[0007]

By providing an arc-shaped expandable portion having a corrugated cross-sectional shape in the cable fixing portion of the earth clamp, when the diameter of the cable to be fastened becomes large, the cable fixing portion has a corrugated arc-shaped sectional shape. Since the expandable part expands and has a spring action, a tensile force acts and a force to tighten the cable is generated. Further, due to the elasticity, the applicable range of the diameter of the cable is widened, so that it is possible to deal with the cables of various different diameters by only one type of the size clamp. This earth clamp is
It can be installed without using screws and a driver simply by placing the bull on the chassis and pressing the clamp downward. Also, at the time of installation, the expansion / contraction part described above causes
Since both ends of the clamp are stretched by being stretched, the parallel upper surfaces of the claws are pressed against the chassis, so that the catch can be secured. Also, when removing,
You can easily remove it by pushing it inward with your finger and pulling.

[0008]

EXAMPLE An example of the present invention will be described with reference to FIGS. In FIGS. 1 and 2, an earth clamp 1 is a cable fixing portion 2 having a corrugated arc-shaped expansion / contraction portion.
And a clamp fixing portion 12 including a U-shaped portion 16 installed at both ends thereof and a pressing plate 15 having a stopper 17 inside the claw (projection) 3. The claw (projection) 3 has a shape in which an inclined surface is provided on the lower side and a surface parallel to the chassis 6 is provided on the upper side. The material of the earth clamp may be plastic or metal as long as it has elasticity and strength. Further, the chassis 6 to which the ground clamp 1 is attached is provided with two mounting holes 7 and a convex portion 8 between the mounting holes 7 by means of a diaphragm. The width l of the convex portion 8 in the length direction of the cable to be fastened is
The width is smaller than the stripping width L of the outer jacket 9 of the cable and larger than the width a of the ground clamp 1. Regarding the length of the cable to be fastened and the dimension in the direction perpendicular to the length, the width c of the rectangular mounting hole of the chassis is made smaller than the width d of the U-shaped portion of the cable fixing portion. When attaching the earth clamp 1 and the cable 4 to the chassis 6, after inserting the U-shaped portion 16 into the attachment hole 7,
The pressing plate 15 and the claw (projection) 3 are put into the mounting hole 7 at the same time.
At this time, the pressing plate 15 hits the inner edge of the mounting hole 7, and the portion having the claw (projection) 3 is pressed and inserted into the outer edge of the mounting hole 7, and the stopper provided on the pressing plate 15 at that time. Prevents 17 from hitting the chassis too much.

Due to the wavy cross-sectional shape provided in the arc-shaped cable fixing portion 2 of the earth clamp 1, this portion has a spring property, and a tensile force is generated against elongation. When the arc-shaped inner diameter of the cable fixing portion 2 of the earth clamp 1 is smaller than the diameter of the cable, the cable fixing portion 2 expands and a tensile force is generated. At this time, the clamp fixing claws (projections) 3 and the pressing plate 15 are provided at both ends of the ground clamp 1, and the surfaces of the claws (projections) 3 parallel to the chassis 6 are engaged with the outer edges of the mounting holes 7. Earth clamp 1 because it is stopped and cannot be removed from the mounting hole
Is securely fixed. Also, because of its wavy shape, it has spring properties, so it is possible to use a cable with a diameter about twice that of the outer circumference.
The application range of one size earth clamp is expanded.
Further, the larger the diameter of the cable 4 is, the larger the tensile force is and the larger the fixing force is. Therefore, an appropriate tightening force can be applied according to the size.

The convex portion 8 provided on the chassis 6 is a cable 4
Since the earth coating 5 of the above is inside the outer coating 9, it is difficult to contact with the chassis 6, so that the outer coating 9 is provided.
Since the shape of the convex portion of the chassis cancels out the thickness of the above, and the contact surface on the upper surface of the convex portion and the ground coating portion are at the same height, reliable contact conduction can be achieved. The ground coating 5 is surely brought into contact with the chassis 6 by the dimensions as described above. Further, by providing the convex portion 8, the outer coating 9 is provided when the cable is pulled from the outside.
Since the outer coating 9 hits the convex portion 8 before hitting the earth clamp 1, no force is applied to the earth clamp 1 to prevent the earth clamp 1 from coming off, and a stable cable can be fixed without applying force to the earth clamp 1.

Also, the lower diagonal surface of the claw (projection) has a function of facilitating insertion when inserting the ground clamp into the mounting hole of the chassis, and the upper parallel surface of the claw (projection) is caught by the chassis. As a result, the ground clamp has the function of making it difficult to pull it out of the chassis. Furthermore, since the width d of the U-shaped portion of the earth clamp is smaller than the width c of the mounting hole of the chassis in the dimension perpendicular to the length of the cable to be fastened, the pressing plate to which the U-shaped end portion is connected is Push the inner edge of the mounting hole of the chassis, and press the claw (projection) side against the outer edge of the mounting hole with the reaction force. As a result, it is possible to securely hook the claw (projection), prevent the ground clamp from coming off, and securely fix the ground clamp. In addition, compared to the conventional screw fastening, the fastening with snap action as described above will
There is a problem that the fixing force becomes weaker than the tensile force applied to the bull. This problem can be solved by setting the width of the convex shape of the chassis to be narrower than the width of the ground clamp. That is, even if the cable is pulled from the outside, the outer coating will hit the convex portion of the chassis before the outer coating pulls the earth clamp due to the dimension, so that an external force is applied to the convex portion of the chassis. become. Therefore, it is possible to prevent the cable pulling force from being applied to the ground clamp, which prevents the ground clamp from coming off.

Another embodiment of the present invention will be described with reference to FIG. In this embodiment, a plurality of claws (projections) 31 are provided on the clamp fixing portion 12 of the earth clamp 1 described in the above embodiment.
And 32 are provided, and the plurality of claws (projections) 31 are provided.
The distance M between and 32 is made larger than the thickness of the chassis. If the diameter of the cable is small, the first claw (projection) 31 is used for fixing the clamp, and if the diameter of the cable is large, the second claw (projection) 32 is used for fixing the clamp. , Change the used claws (protrusions) according to the diameter of the applicable cable. As a result, the range of applicable cable diameters can be further expanded.

Further, another embodiment of the present invention will be described with reference to FIG. In this embodiment, as shown in FIG. 4A, an L-shaped portion 19 and a claw (projection) 20 are provided on the clamp fixing portion 12 on one side of the earth clamp 1 described in the above two embodiments.
Is provided. At the time of mounting, this portion is first inserted into the mounting hole 7, and the claw (projection) 20 is hooked on the mounting hole 21 of the chassis 6 and then the clamp fixing portion 1 on the opposite side.
Attach 8. As shown in FIG. 4B, the chassis 6 in this embodiment has three mounting holes 7, two mounting holes 7 and one hooking hole 21. As a result, there is only one snap attachment portion, and the operability of attachment and detachment is improved. FIG. 5A is a perspective view when the ground clamp having the shape shown in FIG. 4 is attached to the chassis 6, and FIG.
The same sectional view is shown in (b).

[0014]

EFFECTS OF THE INVENTION The grounding clamp of the present invention has good workability, can be attached and detached with one touch without using a tool, and can be used with a single component for a wide range of cable diameters.
The number of man-hours, purchase costs, and management man-hours can be reduced, and the usability is significantly improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the first embodiment of the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing Embodiment 3 of the present invention.

FIG. 5 is a diagram in which an earth clamp according to a third embodiment of the present invention is attached to a chassis.

FIG. 6 is a diagram showing a cable structure (cross-sectional view).

FIG. 7 is a sectional view of a conventional example.

FIG. 8 is a diagram showing a conventional mounting method.

[Explanation of symbols]

 1 Aace Clamp 2 Cable Fixing Part 3 Claw (Protrusion) 4 Cable 5 Aarth Cover 6 Chassis 7 Mounting Hole 8 Convex Part 9 Outer Cover 10 Screw 11 Driver 12 Clamp Fixing Part 13 Cover 14 Core Wire 15 pressing plate 16 U-shaped portion 17 stopper 18 clamp fixing portion 19 L-shaped portion 20 claw (projection) 21 hooking hole 22 cable fixing portion

Claims (1)

[Claims] 1. An earth clamp for grounding a cable, in which a cable having a metal coating covered with a conductive metal is fixed to a chassis by contact, wherein the earth clamp is an arc-shaped cable fixing portion formed in a wavy cross-sectional shape. And a clamp fixing portion having at least one end portion of the cable fixing portion bent inwardly in a U shape and a clamp fixing portion having one or more protrusions provided on the outside. An earth clamp featuring.