JPH11252741A - Knockout hole construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide knockout hole construction of a box which does not need to dispose burrs produced when a hole is punched. SOLUTION: Recessed chipped-off parts 5 are formed in the external brims 3a of cutouts 3 connected by the external end parts of junctions 4 which unite into a body a board section 2 of a box with a punched-off board section 1 to be surrounded by hole punching cutouts 3a formed in the board section 2, and the end sides of the junctions 4 facing on the recessed chipped-off parts 5 are made into thin-breadth parts 4a. Consequently, the thin-breadth parts 4a facing on the recessed chipped-off parts 5 are cut on the occasion of punching the punched board section 1 off. Accordingly, it becomes possible to fit a protecting bush without disposing these burrs, since burrs on the cut surfaces are located inside the hole brim.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knockout hole structure for punching various holes for drawing electric wires and pipes into an electric equipment storage box or the outer shell of an electric equipment and for mounting the equipment. It is.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional knock-out hole structure for an electric equipment storage box or the like is provided with a joining portion 12 at a required portion of a notch 11 for punching a hole, and a punching plate portion 13 and a main body 14 are formed. The connection was integrated. Then, a punch is given to the punching plate portion 13 to cut the joint portion 12, and the punching plate portion 13 is punched to form a hole (A) for drawing in an electric wire, a pipe or the like as shown in FIG. Was.

[0003]

However, in this conventional device, as shown in FIG. 5, the cut portion of the joint 12 protrudes from the edge of the hole (A) formed by punching and becomes a burr. I needed to.

[0004]

In order to solve the above-mentioned problems, a knockout hole structure according to the present invention is provided in which a punching plate portion is joined to a required portion of a notch for punching a hole formed in a plate portion of a box. A notch is provided on the outer edge side of the notch to which the outer end of each joint is connected, and the end of the joint facing the notch is formed in a narrow width portion. It is characterized by the following. Further, it is preferable to form the punched plate portion into a line-symmetric shape by cutting, and to dispose the joint portion symmetrically with respect to the base end of one axis.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described in detail with reference to FIGS. Reference numeral 1 denotes a punching plate portion formed in the plate portion 2 of the electric equipment storage box by being surrounded by a notch 3 for punching holes. The punching plate portion 1 is provided at a required portion of the notch 3 for punching holes. It is integrated with the plate part 2 by the joint part 4 arranged. An outer edge 3a of the notch 3 to which the outer end of each joint 4 is connected is provided with a concave notch 5, and an end of the joint 4 facing the concave notch 5 has a narrow width portion 4.
a. Further, the punched plate portion 1 is formed in a line-symmetrical shape, that is, an elliptical shape by the cuts 3, and the joint portions 4 and 4 are disposed symmetrically with respect to the base end of the short axis which is one axis line. .

As shown in FIG. 3, a plurality of knockout hole structures having such a structure are provided on a back plate 2 which is a required plate 2 of an electric equipment storage box, and are provided at positions where electric wires, pipes and the like are drawn. The punch plate 1 having a knockout hole structure is punched to form a hole having an outer edge 3a of the cut 3 as an outer shape. At this time, in order to integrate the punched plate portion 1 formed in the plate portion 2 by being surrounded by the cutout 3 for punching holes, the joining is provided at a required position of the cutout 3 so as to be integrated with the plate portion 2. The outer end of the joint 4 is connected to a concave notch 5 provided on the outer edge 3 a of the cut 3, and the end side of the joint 4 facing the concave notch 5 is a narrow width portion. Since the punched plate portion 1 is formed by pressing the punched plate portion 1 with a tool or the like, the narrow width portion 4a is cut and the punched plate portion 1 is punched. At this time, as shown in FIG. 2, since the narrow portion 4a, which is the cut portion, is located in the concave portion 5, the burr on the cut surface is located inside the edge of the hole. If the protection bush is attached, the recessed portion is concealed by the protection bush, so that the appearance is good.

Further, the punching plate 1 is formed in a line-symmetrical shape, that is, an elliptical shape by the cuts 3, and the joints 4, 4 are disposed symmetrically with respect to the base end of the short axis which is one axis. By pressing a position away from the short axis of the punching plate portion 1 to be formed into an elliptical shape, the punching plate portion 3 rotates about the joining portions 4 and 4 to form a joining portion. 4, 4 narrow portions 4a, 4
a can be easily cut off. In this case, pressing the end of the punched plate portion 1 farthest from the short axis increases the torque, so that less force is required. In addition,
The punching plate portion 1 may be circular, elliptical, square, or rectangular in addition to the oval shape as the line-symmetric shape due to the cut 3. In the case where the cut 3 is provided at the opening edge of the box, it is needless to say that the cut 3 is provided in a U-shape.

[0008]

According to the present invention, as is apparent from the above description, when the punched plate portion 1 is punched to form a hole, the narrow portion of the joining portion, which is the cut portion, is located in the concave notch. Since the burr on the cut surface is located inside the hole edge, there is no need to treat the burr. Accordingly, the present invention is of great benefit to the industry as a solution to the problem of the conventional knockout hole structure of a box.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a front view showing a state in which holes according to the embodiment of the present invention are formed.

FIG. 3 is a perspective view showing an embodiment of the present invention.

FIG. 4 is a front view showing a conventional example.

FIG. 5 is a front view showing a conventional example in which holes are formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Punched plate part 2 Plate part 3 Cut 3a Outer edge of cut 4 Joining part 4a Narrow width part 5 Concave notch

Claims (2)

[Claims] A joint (4) is provided at a required portion of a notch (3) for punching a hole to form a punching plate (1) in a plate (2) of a box. 4) the notch (3) to which the outer end of
Knockout characterized in that a concave notch (5) is provided on the outer edge (3a) side of the joint, and an end side of the joint (4) facing the concave notch (5) is formed in a narrow width portion (4a). Hole structure. 2. A punching plate (1) is formed in a line-symmetrical shape by a cut (3), and is symmetrical to a base end of one axis to form a joint (4).
The knockout hole structure according to claim 1, wherein (4) is provided.