JPH11287235A - Nut protection cap and uncapping tool therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the drawing-out of a nut from a bolt by forming cylindrical part in a nut protection cap of magnetic material, constructing it of a large diameter bore cylindrical part and a small diameter bore cylindrical part, sticking a permanent magnet in a stepped part between them, and attaching the nut protection cap to a already installed fastened member by means of magnetic force. SOLUTION: When, in a pipe steel tower, pipes P1, P2 are connected together via opposed flanges F1, F2 by means of a bolt, a protection cap 1 is put over an already arranged nut, and the protection cap 1 is sucked to the flange F1 by means of the end edge of a large diameter cylindrical part 1a. In the protection cap 1, its outline is constructed of the large diameter cylindrical part 1a and a small diameter cylindrical part 1b, and a stepped part is formed of the large diameter bore and a small diameter bore in the corresponding cylindrical parts respectively. In the stepped part, a permanent magnet 2 is stuck, and a line of magnetic force is formed between the flange F1 face and it. In the end face of the small diameter cylindrical part 1b, a through hole 1c is bored with a slight clearance between a flange bolt B and it, and around the through hole 1c, a small hole 1d for an uncapping tool is bored.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective cap for a nut attached to the outside of a tightened nut, and to prevent the nut from being removed with a general-purpose tool.

[0002]

2. Description of the Related Art An example in which the present invention is used for a flange bolt of a pipe tower of a transmission line will be described. The pipe tower is composed of four main legs, supporting members connecting them, an upper arm portion, and the like. The main legs are connected to a plurality of pipe members by bolts with flanges. Its foundation leg is about 1.5m above the ground, and pipes are being added one after another. A plurality of opposing bolt holes are formed in the flange of each pipe member, and the bolts are penetrated and tightened with nuts, and then locked with lock nuts. The main landing gear is provided with a lifting bolt, but the steps on the lower tower leg are always removed to prevent unexpected accidents caused by the intruder's mischief. In addition, steel towers in urban areas are surrounded by fences to prevent these intrusions. However, the cause is that the lower flange bolt of the tower was loosened by malicious mischief, as in the recent collapse of the tower, and such mischief cannot be prevented by the conventional methods.

[0003]

It is required that the connection bolt of the tower flange be removed with a general-purpose tool in addition to preventing the nut from being loosened. If someone tries to remove an existing bolt and nut with a general-purpose hexagonal wrench, no mischief can be made unless the nut is covered and exposed. An object of the present invention is to provide a nut protection cap and a tool for removing the nut, which can be easily attached only to the existing nut and can be removed only with a special tool.

[0004]

According to the first aspect of the present invention, the cap body is made of a magnetic material, which is composed of a large-diameter cylindrical portion and a small-diameter cylindrical portion, and the step of the through hole is formed. A permanent magnet is adhered to the attached portion so as to face the flange, and this is inserted from the tip of the bolt to cover the nut. Since the permanent magnet forms a line of magnetic force between the cap and the existing tightened member and can be strongly attracted, the cylindrical cap is strongly fixed with the nut covered by the nut. Even if a general-purpose tool such as a hexagon wrench is used, it cannot be removed by fitting it to the nut unless the cap is removed. According to the second aspect of the present invention, a ring-shaped permanent magnet is bonded to the stepped portion to form a magnetic line of force between the ring and the existing tightened member, and the cap body is strongly attracted to the flange. According to the third aspect of the present invention, the cylindrical portion is made of resin, a magnetic ring having an L-shaped cross section is fixed from the stepped portion of the large and small holes to the large diameter hole, and a permanent magnet is adhered to the magnetic ring. The ring forms a line of magnetic force on the existing tightened member, and is strongly attracted. According to the invention described in claim 4, the small-diameter hole cylindrical portion drills a concentric hole having a slight gap with the existing bolt end on the end face,
A small hole is made around the concentric hole so that only a specially prepared removal tool can be removed. According to the fifth aspect of the invention, a U-shaped trigger having an outward locking claw on both ends and a screw hole formed in a central portion, and a pusher screwed into the screw hole and provided with a rotating portion on an upper portion. This is a tool for removing a protective cap composed of a bolt and a hook.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a pipe tower in which upper and lower pipes P1, P2 are bolted together by opposed flanges F1, F2. This existing nut is covered with the protective cap 1 of the present invention, and is strongly attached to the flange by the edge of the large-diameter cylindrical portion 1a. As shown in FIG. 2, the protective cap 1 has a large-diameter cylindrical portion 1a and a small-diameter cylindrical portion 1b, each of which has a step with a corresponding large-diameter hole and small-diameter hole. A permanent magnet is adhered to the stepped portion, and forms a line of magnetic force with the flange surface of the tower. A plurality of permanent magnets or a ring-shaped permanent magnet can be more strongly attracted. Further, the protective cap relatively easily moves in the direction of the flange surface due to the characteristics of the magnet, but cannot be easily removed because the movement is prevented by the existing nut. A concentric through-hole 1c is drilled in the end face of the small-diameter cylindrical portion with a slight gap from the flange bolt B, and around the hole, a small hole for a removal tool used for removing a protective cap described later. 1d is open. This through hole 1c is unnecessary when it is not necessary to remove the cap. FIG. 3 shows that a magnetic material ring 3 having an L-shaped cross section is bonded to the stepped portion of the large and small holes of the resin cap body, and a permanent magnet is bonded to this ring by positioning the permanent magnet inside the edge of the cap. The magnetic lines of force formed between the third member 3 and the flange F <b> 1 strongly attract each other.

[0006] While the protective cap that is strongly attracted by the permanent magnet cannot be easily removed,
A tool that can be easily removed is necessary in consideration of the inspection of the nut and the case where the cap is incorrectly attached. FIG.
It is a special tool (removal tool) for that. Removal tool 4
Has a U-shaped trigger 4a having an outwardly extending locking claw 4c at the tip of each half leg, and having a threaded hole at the center, and a hexagonal part with a handle at the top screwed into the threaded hole. And a push bolt 4b provided with The leg of the trigger 1a is slightly elastic due to the half groove. Protective cap 1
When removing the cap, the claw 4c of the removal tool 4 is inserted into the small hole in the upper end face of the cap and hooked. When the push bolt 4b is rotated with a wrench on the upper handle or the hexagonal portion, the existing flange bolt is pushed by the tip of the push bolt, and the trigger 4a is pulled off the protective cap 1 and comes off.

If an inexperienced person tries to remove the protective cap with a hammer with a hammer,
It is stopped by the nut and also fixes the movement in the direction of the surface where the suction force is weak, so that it can be prevented.

[0008]

According to the present invention, since it is a simple operation of merely covering the existing bolt nut from the outside of the nut, even if there is an urgency for a large number of bolt nuts, it can be handled very quickly. Attached member (connection flange for pipe tower)
The protective cap cannot be removed with a general-purpose tool, and it is impossible to remove the existing bolt and nut, thereby preventing the removal of the bolt and nut due to mischief. Further, the special tool can be easily removed as needed, so that maintenance and inspection of the bolt and nut can be performed.

[Brief description of the drawings]

FIG. 1 is a front view showing a usage example of a protective cap.

FIG. 2 is a cut-away front view of a protective cap.

FIG. 3 is a cutaway front view showing another embodiment of the protective cap.

FIG. 4 is a plan view of a protective cap.

FIG. 5 is a front view of a removal tool.

FIG. 6 is a side view of the removal tool.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Protective cap 1a Large-diameter cylindrical part 1b Small-diameter cylindrical part 1c Through-hole 1d Small hole 2 Permanent magnet 3 Sectional L-shaped ring 4 Removal tool 4a Trigger 4b Push bolt 4c Locking claw P1, P2 Pipe tower F1, F2 Flange B bolt N nut

Claims (5)

[Claims] 1. A cylindrical part made of a magnetic material includes a large-diameter hole cylindrical part and a small-diameter hole cylindrical part. A permanent magnet is adhered to the stepped part of the large and small holes. A protective cap for a nut, wherein a permanent magnet forms a line of magnetic force on an existing member to be tightened so as to be attracted when the nut is put on the nut. 2. The protective cap for a nut according to claim 1, wherein a ring-shaped permanent magnet is bonded to the stepped portion. 3. The cylindrical portion is made of resin, a magnetic ring having an L-shaped cross section is fixed from the stepped portion to the large-diameter hole, a permanent magnet is bonded to the magnetic ring, and the magnetic ring is an existing tightened member. 3. The protective cap for a nut according to claim 1, wherein a magnetic line of force is formed on the nut to be attracted. 4. A small hole for a tool is formed in an end face of a small-diameter hole cylindrical portion with a small gap between the end of the small-diameter hole cylindrical portion and an existing bolt, and a peripheral hole is removed therefrom. The protective cap for a nut according to claim 3. 5. A U-shaped trigger having outwardly engaging locking claws at both ends and having a screw hole formed at a center portion, and a push bolt screwed into the screw hole and provided with a rotating portion at an upper portion. 6. A tool for removing a protective cap, wherein the protective claw is detachable by engaging a locking claw in the small hole according to claim 5.