JPH0331469Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a device for removing defective rivets that often occur during the manufacture of chassis frames for large vehicles.

(Prior Art) Hydraulically actuated riveting devices, which have been widely used in the manufacture of chassis frames for large vehicles, have a hydraulic cylinder attached to one end of a frame or yoke that is generally U-shaped or C-shaped. A snap is provided in which a piston that is reciprocated by hydraulic pressure is fitted into the same cylinder, and a snap is attached to the shaft end of the cylinder and the other end of the frame opposite to the coaxial end, so that the rivet head is formed in cooperation with the other end of the cylinder. It has a structure in which each can be attached and detached. When performing tack work using such a tack machine, if the length of the tack shaft is longer or shorter than the allowable limit than the standard size, the tack head may not be formed correctly and may not be aligned with the tack axis. The head may be unevenly molded or the molded head may be of insufficient size.
As is well known in the art, rivets with malformed rivet heads may not be able to provide the desired strength, so they must be removed and replaced with new rivets. Conventionally, when removing the defective rivets mentioned above, a special shearing tool with a handle attached to a chisel was applied to the rivet head, the shearing tool was struck with a sledgehammer to shear the rivet head, and then the handle was attached to the punch. A special punching tool was applied to the remaining rivet shaft, and the punching tool was struck with a sledgehammer to remove the rivet shaft.

(Problems to be solved by the invention) In the conventional method for removing defective rivets described above, the shearing of the rivet heads and the extraction of the rivet shafts were each performed by hitting a special tool with a sledgehammer. There was a problem that was dangerous, required a lot of work time, and led to high costs.

(Means for Solving the Problems) The present invention was devised in view of the above, and the outer diameter of the end that comes into contact with the regular-shaped tack head is slightly smaller than the outer diameter of the tack shaft after the tack is mounted. a first snap provided with a punched-out pin in the form of a tapered pin having an outer diameter that gradually increases as it moves away from the end, and a molded rivet head with a malformed shape is accommodated in the end opposite to the small diameter end of the first snap. a second snap having a recess; one of the first and second snaps is removably attached to one end of the generally U-shaped rivet machine frame, and the other snap is attached to the frame. It is removably attached to the piston shaft end of the hydraulic cylinder mounted on the other end, and the annular remaining material of the punched rivet head is placed on the outside of the punched pin of the first snap, facing toward the small diameter end of the pin. An ejector made of an elastic material such as rubber that can be pressed by pressing is installed, and a protective cap is attached to the end of the ejector on the small diameter side of the punching pin to prevent excessive deformation of the ejector in the radial direction. It is characterized by the fact that

(Example) Examples of the present invention will be specifically described below with reference to the accompanying drawings. The reference numeral 10 in the drawing generally indicates a well-known hydraulic rivet machine, and the rivet machine has a generally U-shaped frame or yoke 12, and is fastened to one end of the frame 12 by a nut 14. A hydraulic cylinder 16 is provided, and a piston 18 is slidably fitted within the cylinder, and a first snap 2, which will be described in detail later, is attached to the end of a shaft 18' of the piston 18.
0 is detachably attached to the frame 12, and a second snap 22, which will be described in detail later, is detachably attached to the other end of the frame 12.

Next, as shown enlarged in Figure 2,
The first snap 20 includes a handle 20a and a punched pin 20b that are fitted into a fitting hole provided at the end of the piston shaft 18'. The handle 20a has a groove 2 with a semicircular cross section into which an O-ring is fitted to prevent it from falling off.
0c, while the punched pin 20b has a regular-shaped stud head 24a preformed on the stud 24.
The outer diameter d ₁ of the lower end that comes into contact with the rivet shaft 24 after the rivet is
It has a tapered pin shape that is slightly smaller than the diameter d ₂ of b and has a diameter that gradually increases upward. As an example, when the diameter of the rivet hole before the rivet is 10.6 mm and the rivet shaft diameter d ₂ after the rivet is approximately 11 mm, the diameter d ₁ of the lower end of the pin 20b is 10 mm, and the diameter d ₃ of the upper end is approximately 11 mm. It is preferable that there be. A cylindrical sleeve 28 with an open lower end and an appropriate annular gap 26 is concentrically surrounded around the outer periphery of the punched pin 20b, and an appropriate radial play t is provided within the sleeve 28.
An ejector 30 made of rubber or the like is fitted therein. A metal protective cap 32 is fixed to the lower end surface of the ejector 30 to prevent damage caused by an elastic material such as rubber coming into direct contact with the rivet head. When compressed, the sleeve 2
The ejector is provided with a cylindrical portion 34 that cooperates with the ejector 8 to prevent excessive radial outward deformation of the ejector.

Next, the second snap 22 is attached to the frame 12.
It is composed of a handle 22a that is fitted into a fitting hole provided at the other end, and a receiving part 22b. A cross-sectional groove 22c is provided. The receiving portion 22b is provided with a rectangular groove-shaped recess 22d for accommodating the rivet head 24c of the rivet 24, which is formed into a defective shape.

When setting rivets using the rivet machine 10, ordinary rivet head forming snaps (not shown) are attached to both ends of the frame 12 in place of the first and second snaps 20 and 22. There is. and,
The shaft portion 24b of the rivet 24 having a predetermined rivet diameter is attached to the material 36a to be riveted.
and 36b, and the rivet head is press-formed by the rivet shaft portion protruding from the material to be riveted 36b. That is, the rivet head 24a and the end of the rivet shaft that will be molded into a new rivet head are positioned between the upper and lower snaps,
By operating the operation button 36, hydraulic pressure oil is supplied to the piston upper chamber of the hydraulic cylinder 16 by actuation of the hydraulic control device 40, and the piston shaft 1
8' and the upper snap are lowered together to perform the riveting operation. At this time, if the axis of the rivet shaft 24b and the upper and lower snap axes do not substantially match and the center line of the pressing force is significantly inclined with respect to the rivet shaft, the rivet shaft 24b
If the length of the rivet is too long or too short, a rivet head 24c of a defective shape as shown in FIG. 2 may sometimes be formed. A tack head 24 with such a defective shape
In case c, the desired riveting strength cannot be ensured, so it is necessary to remove the defective studs and perform riveting again with new studs. In this case, as shown in FIG.
A first snap 20 is installed on the 8' side, and a second snap 22 that cooperates with the other end of the frame 12 is attached.
2, the defective rivet head 24c is fitted into the recess 22d of the second snap 22, and the first snap 20 is tightened using hydraulic pressure in the same manner as normal rivet work. is pressed against the second snap 22. Then, the lower end of the punching pin 20b of the first snap 20 comes into contact with the regular-shaped rivet head 24a, and the rivet head is punched out into a donut shape, leaving behind a donut-shaped annular body and removing the rivet shaft 24b and the defective rivet head. 24c falls into the recess 22d of the second snap 22, and the defective studs are removed safely, quickly, and at low cost. Next, when the piston 18 of the rivet machine 10 returns to the inoperative position shown in FIG.
0 automatically expands and strongly presses the annular rivet head remaining material fitted to the outer periphery of the punching pin 20b through the protective cap 32, so that the punching pin 2
The fact that 0b is in the shape of a tapered pin also contributes to the fact that the annular rivet head residue is usually automatically removed. Therefore, the first and second snaps 20 and 2
2 is replaced with a normal rivet snap, and the new rivet work is carried out again.

(Effects of the Invention) As already mentioned, according to the present invention, defective rivets can be removed safely and quickly, and therefore at low cost. Furthermore, after removing the defective rivet, it is necessary to remove the annular rivet head residue remaining on the first snap, but due to the elastic force of the ejector 30 and the tapered shape of the punching pin, the rivet head residue is usually removed. This is extremely advantageous since it is automatically removed. In addition, even in the rare case that the tack head remaining material is twisted and remains without being removed, the elastic force of the ejector 30 is still working, so for example, the tack head remaining material may be held by pliers and a slight rotational force applied. This has the advantage that the remaining tack head material can be removed quickly and easily. Furthermore, the ejector 30 is compressed when punching out the rivet head, but the ejector made of an elastic material such as rubber does not come into direct contact with the rivet head, but receives the punching force through the protective cap 32, so it is not damaged. The durability of the ejector 30 can be ensured since there is little danger of this occurring, and excessive radial deformation is prevented by the cylindrical portion 34 of the protective cap 32 and the sleeve 28 during compression. Note that the sleeve 28 may be omitted and the cylindrical portion 34 of the protective cap 30 may be placed in the position of the illustrated sleeve, or the cylindrical portion 34 may not be placed outside the sleeve 28 but may be placed on its inner peripheral surface. It may also be changed so that it slides along.

[Brief explanation of the drawing]

Fig. 1 is an overall side view showing an embodiment of the present invention, Fig. 2 is an enlarged side sectional view of the main part of Fig. 1, and Fig. 3 is a cross section taken along the - line in Fig. 2. It is a diagram. 10...tack machine, 12...frame, 16...
Hydraulic cylinder, 18...piston, 20...first
Snap, 22...Second snap, 24...Tack,
30... Executor, 32... Protective cap.

Claims (1)

[Scope of utility model registration request] A punched-out pin in the form of a tapered pin, the outer diameter of the end of which comes into contact with the regular-shaped rivet head is slightly smaller than the outer diameter of the rivet shaft after the rivet has been tacked, and the outer diameter gradually increases as it moves away from the end. a second snap having a recess for accommodating a malformed rivet head at an end opposite to the small diameter end of the first snap; , is removably attached to one end of the riveting machine frame having a roughly U-shape, and the other snap is removably attached to the end of the piston shaft of a hydraulic cylinder mounted on the other end of the frame; An ejector made of an elastic material such as rubber that presses the annular remaining material of the punched rivet head toward the small diameter end of the pin is disposed on the outside of the punching pin of the first snap, and the ejector is also A defective rivet extractor characterized in that a protective cap for preventing excessive deformation of the ejector in the radial direction is attached to the small-diameter end of the extractor.