JP3312671B2 - Swivel joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swivel joint used as a joint in an excavator, a ground improvement machine and other construction machines, which requires a relatively rotatable connection between two members.

[0002]

2. Description of the Related Art FIG. 5 is a side view showing a vertical drilling earth drill which is an example of a construction machine using a swivel joint. A swivel joint 1 is wound around a winch 3 on an earth drill body 2 and A hoisting rope 6 suspended via a sheave 5 at the top of the boom 4 and a kelly bar 8 having a lower end to which a digging bucket 7 is attached are connected so as to be relatively rotatable. A front frame 9 is mounted on the main body 2 so as to be able to move up and down, and a kelever driving device 10 is mounted on an upper part of the front frame 9. It is inserted so that relative rotation is impossible. The swivel joint 1 is provided to prevent the rotation of the kerry bar 8 during excavation from being transmitted to the hoisting rope 6.
At the same time as the winch 3
Pay out.

FIGS. 6A and 6B are a longitudinal sectional view and a front view of the swivel joint 1, respectively. As shown in these figures, the swivel joint 1 is formed by rotatably and concentrically connecting an upper body 12 called an eye end and a lower body 13 called a shaft. For coupling, a cylindrical casing 14 is fixed to the lower part of the upper body 12, and a shaft 15 is concentrically fixed to the upper part of the lower body 13, and a bearing 16 is provided between the shaft 15 and the casing 14. Is provided. Upper body 1
2 has a notch 12a for inserting a thimble 6a at the end of the hoisting rope 6 as a connected member.
The connecting pin 17 is attached so as to form a crotch shape and cross the notch 12a. The connection pin 17 is attached by inserting a rod spanner into one of the square holes 17a provided at both ends of the connection pin 17 as shown in a partially enlarged sectional view of FIG. The portion 17b is screwed into the screw hole 12b provided in the body 12, and the tapered head portion 17c is tightly fitted into the tapered hole 12c, whereby the axial force due to the tightening of the screw portion 17b and the tapered portion 17c The connection pin 17 is firmly connected by the contact surface pressure in the above to prevent the connection pin 17 from coming off. Similarly, the connection pin 18 connected to the kelly bar 8 has a square hole 18a, a screw portion 18b, and a tapered portion 18c.

The reason why the structure for preventing the connection pins 17 and 18 from falling off is employed is as follows. The load applied to the hoisting rope 6 during the excavation work is the sum of the weight of the keriba 8 and the excavating bucket 7 and the weight of the excavated earth and sand, and the weight acts on the hoisting rope 6 as tension.
The twist of the hoisting rope 6 is extended. Drilling bucket 7
When the excavated soil is full, the winch 3 is operated to wind up the hoisting rope 6, the excavating bucket 7 is pulled up to the ground, and the excavated soil is discharged on the ground. At the moment when the landing gear 7 lands on the ground, the weight applied to the hoisting rope 6 is reduced or almost eliminated, so that the stretched twist of the hoisting rope 6 returns instantaneously, and the swivel joint 1 rotates at high speed. During this high-speed rotation, the hoisting rope 6 side connection pin 17 of the swivel joint 1 receives the instantaneous rotational force of the twisting back of the hoisting rope 6, whereby the connecting pin 17 tries to escape outward due to centrifugal force. Force is generated.

[0005] In order to prevent the connection pin from coming off due to the high-speed rotation of the swivel joint 1, the screw 17b and the tapered portion 17c increase the adhesion of the connection pin 17 to prevent loosening.

[0006]

However, when transporting after excavation work is completed, it is necessary to disconnect the hoisting rope 6 and the kelly bar 8 for the divisional transportation of parts. Therefore, it is necessary to remove the connection pin 17 connecting the hoisting rope 6 or the connection pin 18 connecting the kelly bar 8, but it is difficult to remove the connection pin due to rust or the like, and in the worst case, However, there is a problem that cutting may be required due to gas fusing or the like.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a swivel joint having a structure in which a connection pin does not come off and which can be easily removed.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a construction machine and at least one of two bodies which are rotatably and concentrically connected to each other. In a swivel joint provided with a connection pin connected to an end, the connection pin is a headed pin having a retaining head, and an annular groove is provided around a distal end of the connection pin, A pair of pins for projecting the tip of the pin so that the annular groove is exposed outside the pin hole of the body to prevent the connection pin from coming off.
A retaining plate is provided, and the pair of retaining plates are mutually butted.
An arcuate notch formed in the sides, wherein the circular fitting made to have a gap in an annular groove, and has retained the connection pins and secured by bolting respective retaining plate to said body .

In the present invention, the mounting surface of the retaining plate of the body is a concave flat portion, and a pair of retaining plates is fitted into the flat portion so as to sandwich the connection pin between the retaining plates. It is more preferable to have a structure in which a stopper bolt is loosely fitted in a hole provided in the retaining plate and screwed into a screw hole provided in the flat portion.

[0010]

According to the present invention, the arc-shaped notch of the retaining plate is fitted into the annular groove of the connection pin via a gap.
It will be locked. When the retaining function is exerted by the retaining plate as described above, it is not necessary to firmly fix the connecting pin to the mounting hole as compared with a case where the connecting pin is prevented from being removed by the tapered portion or the screw portion. The movement of the connection pin in the axial direction (direction of removal) acts only perpendicularly to the surface of the retaining plate and does not act in the direction in which the retaining plate slides. Does not act on retaining bolts. Further, if the retaining plate is structured such that a retaining bolt is loosely fitted in a hole provided in the retaining plate and screwed into a screw hole provided in the flat portion, the force acting on the retaining bolt is further reduced. .

[0011]

FIG. 1 is a plan view showing a main part of an embodiment of a swivel joint according to the present invention, and FIGS. 2A and 2B are a longitudinal sectional view and a front view, respectively, of the embodiment. This embodiment is an example of a swivel joint used for coupling the hoisting rope 6 of the earth drill and the kelly bar 8 in the same manner as the conventional example shown in FIGS. Reference numerals indicate the same components and parts.

Reference numerals 20 and 21 denote connection pins for connecting the thimble 6a and the keriba 8 of the hoisting rope 6, respectively.
These are pins with heads 20a and 21a having the same structure as each other, and these pins 20 and 21 are inserted into pin holes 12d and 13d provided in the bodies 12 and 13, respectively, with loose dimensions. Also, the heads 20a, 21a of the connection pins 20, 21 are brought into contact with the flat portions 12e, 13e formed in a concave shape at one end of the pin holes 12d, 13d, and the ends of the connection pins 20, 21 are connected to each other. And project from the flat portions 12f and 13f formed in a concave shape.

Although these pins 20 and 21 have the same mounting structure, the following description is based on the connection pin 2 on the hoisting rope 6 side.
0 will be described as a representative. As shown in the exploded perspective view of FIG. 3, an annular groove 20b is provided at the tip of the connection pin 20. Reference numeral 22 denotes a retaining plate having an arc-shaped notch 22a fitted into the groove 20b.
As shown in the vertical cross-sectional view of FIG. 3, the upper and lower ends of the retaining plate 22 contact the upper and lower end surfaces 12h, 12h of the flat portion 12f so as to be fitted immovably up and down. As shown in the cross-sectional view of FIG. 4C, two of these retaining plates 22 are provided, and connection is made from both left and right sides of the connection pin 20 such that the arc-shaped notch 22a is fitted into the groove 20b of the connection pin. It is attached so as to sandwich the pin 20.

As shown in FIG. 4B, the arc-shaped notch 22
The radius of curvature of “a” is such that the diameter d2 of the circle formed by combining the two retaining plates 22 is slightly (about 1 to 2 mm) larger than the diameter d1 of the groove 20b, and the diameter d3 of the connection pin 20 is large. It is set to be smaller.
The pair of retaining plates 22, 22 are manufactured by forming a circular hole at the center of a rectangular plate and cutting the plate into two equal parts at the center. Each retaining plate 22 has a circular hole 22b through which two retaining bolts 23 for retaining are inserted.

As shown in FIG. 3 and FIG.
A rectangular or hexagonal head 23a is formed so that the head can be tightened with a spanner, and a circular flange 23b is formed thereunder. The diameter of the flange 23b is the diameter of the bore 22b. Set slightly smaller. Flat part 1
2f is provided with a screw hole 12g into which the stop bolt 23 is screwed.

As shown in FIG. 1 and FIG.
When the head 20a is brought into contact with one of the flat portions 12e, the groove wall 20d on the head side of the groove 20b is exposed from the flat portion 12f so as to be substantially flush with the flat portion 12f. Inserted into. Then, the retaining plate 22 is slid along the plane portion 12f from the left and right sides of the plane portion 12f and fitted between the upper and lower end surfaces 12h, 12h, so that the arc-shaped notch portion 22a is fitted into the groove 20b, and the stop bolt 23
Through the cutout hole 22b of the retaining plate 22, and the flat portion 12
Screw into the screw hole 12g of f. In this state, as shown in FIG. 1, a gap G1 is formed between the arc-shaped notch 22a and the bottom surface of the groove 20b, and the thickness of the retaining plate 22 is set slightly smaller than the width of the groove 20b. Therefore, a gap G2 is also formed between the tip 20c of the connection pin 20 (or between the head 20a and the side wall surface 20d of the groove 20b when the pin 20 is retracted) and the plate surface of the notch 22a. . In this state, the retaining plate 22 is prevented from coming off due to the axial movement of the retaining plate 22 by the distal end portion 20 c of the connecting pin 20, and the retaining bolt 22 is prevented from moving left and right by the retaining bolt 23. . As a result, the leading end portion 20c is cut out from the groove 20b of the connection pin 20 by the cutout portion 22a.
Is locked to prevent it from falling off. In this state, a gap G1 is formed between the notch 22a and the groove 20b of the connection pin 20,
Due to the presence of G2, only the axial movement of the connection pin 20 acts on the retaining plate 22, and is not transmitted to the retaining plate 22 even if the connection pin 20 vibrates or rotates. 23 is less likely to loosen.

Further, since the loose fitting structure in which the diameter of the hole 22b of the retaining plate 22 is set larger than that of the flange portion 23b of the retaining bolt 23, when the retaining plate 22 is fitted into the flat portion 12f, Since the vertical movement of the retaining plate 22 is prevented, the upper and lower inner peripheral surfaces of the hole 22b and the flange portion 23b are prevented.
Is in a non-contact state, and there is no possibility that the locking bolt 23 will come off due to the force. Further, since the arc-shaped notch 22a is prevented from coming off by the distal end portion 20c of the connection pin 20, and the retaining plate 22 is fitted into the plane portion 12f,
Even if one of the two locking bolts 23 comes off, the left / right movement of the retaining plate 22 is prevented by the retaining bolt 23, and the retaining plate 22 does not come off, and the safety is high. Even if one of the pair of retaining plates 22 falls off, the connection pins 20 are retained as long as the other retaining plate 22 remains, and the safety is high.

The present invention can be applied not only to an earth drill but also to a swivel joint used in other excavators, ground improvement machines and the like. Also, the collar 2 is attached to the fixing bolt 23.
It is also possible to use a normal bolt having no 3b, and in the case of using a normal bolt, even if the head of the bolt is fastened and fixed in contact with the retaining plate, the arc-shaped notch 22a and the groove 20b may be used. As long as there is a gap between
Since the transmission of the movement from the connection pin 20 to the retaining plate 22 is reduced, the retaining bolt is less likely to come off, so that the object of the present invention can be achieved . Further, the present invention is not limited to a swivel joint having two connection pins, but can be applied to a body in which one body is connected to one connected member by a bolt or the like.

[0019]

According to the first aspect, a pair of retaining plates are provided.
The retaining plate is provided with an arc-shaped notch,
Since the part is inserted into the groove of the connection pin with a gap to prevent it from coming off, the vibration and rotation of the connection pin do not act on the retaining plate or the retaining bolt, so the retaining bolt does not come off, As a result, the connection pins are reliably prevented from coming off. Further, since it is not necessary to firmly fix the connection pin to the pin hole, the connection pin can be easily attached and detached.

According to the second aspect of the present invention, the retaining plate is fitted into the concave flat portion, and a retaining bolt is loosely fitted into a hole provided in the retaining plate and screwed into a screw hole provided in the planar portion. Therefore, the force acting on the stop bolt is further reduced, and the possibility that the stop bolt comes off is further eliminated. In addition, since two retaining plates are provided, even if one retaining plate comes off, the other retaining plate prevents the retaining plate from falling off, so that the safety is high.

[Brief description of the drawings]

FIG. 1 is a plan view showing a main part of one embodiment of a swivel joint of the present invention.

FIGS. 2A and 2B are a longitudinal sectional view and a front view, respectively, of the swivel joint of the embodiment.

FIG. 3 is an exploded perspective view showing a part of the swivel joint of the embodiment.

FIG. 4A is a longitudinal sectional view showing a state of attachment of the retaining plate of the embodiment, and FIG. 4B is a front view thereof.

FIG. 5 is a side view of an earth drill which is an example of a machine using the swivel joint.

6A is a longitudinal sectional view of a conventional swivel joint, FIG. 6B is a front view thereof, and FIG. 6C is a partially enlarged sectional view of FIG.

[Explanation of symbols]

12, 13: body, 12d: pin hole, 12e, 12
f: flat part, 12g: screw hole, 20, 21: connection pin,
20a: head, 20b: groove, 22: retaining plate, 22
a: arc-shaped notch, 22b: drilled hole, 23: locking bolt,
G1, G2: gap

Claims (2)

(57) [Claims] 1. A swivel joint for use in a construction machine, wherein at least one of two bodies rotatably and concentrically coupled to each other is provided with a connection pin connected to an end of a member to be connected. The connection pin is a headed pin having a head for retaining, and an annular groove is provided around the tip of the connection pin. A pair of retaining plates are provided to protrude so as to be exposed to the outside and to prevent the connection pins from coming off.
An arc-shaped notch provided at the butted sides of the pair of retaining plates is fitted into the annular groove with a gap,
And swivel joints, characterized in that it has retained the connection pins and secured by bolted respective retaining plate to said body. 2. The device according to claim 1, wherein the mounting surface of the retaining plate of the body is a concave flat portion, and the retaining plate forming a pair with the flat portion is arranged so that the connecting pin is sandwiched between these retaining plates. A swivel joint which is fitted and screwed loosely into a hole provided in a retaining plate and screwed into a screw hole provided in a flat portion.