JPH0428423Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention fixes pipe-shaped branch rods to the lower ends of vertically extending pedestals so that they extend radially in plan view, and The present invention relates to an improvement in the structure for attaching the casters to a branch leg in a chair leg device in which a caster with a roller is provided on the lower surface of the tip of the leg.

[Conventional technology]

As described above, various ideas have been devised as means for attaching casters to the tips of branch rods, and as one example, Japanese Utility Model Publication No. 141539/1983 discloses a method for attaching casters to the tip of a branch rod with a U-shape with a downward opening in cross section. A supporting piece with a nut fixed to it is fixed by welding to the lower surface of the top plate at the tip of this branch rod, so that the branch rod is completely covered with the support piece. A cover body formed in a bag shape is fitted over the branch rod from the distal end direction, and a bolt insertion hole concentric with the screw hole of the nut is bored in the bottom plate of the distal end of the cover body. A device has been disclosed in which a mounting bolt is screwed into a nut through the bolt insertion hole.

[Problem that the invention attempts to solve]

However, in the configuration in which the nut is fixed to the support piece fixed to the branch rod as in this prior art, the position of the nut remains unchanged, so errors in machining of the support piece, errors in the welding position of the nut, or errors in the cover Due to an error in the position of the bolt insertion hole when machining the body, the axis of the nut and the axis of the bolt insertion hole in the cover body were misaligned along the longitudinal direction of the branch rod. There was a problem where the caster mounting bolt could not be screwed into the nut.

In addition, the load of the chair acting on the nut via the caster is supported only by the support piece, which not only tends to deform, but also has a U-shaped cross section with a downward opening. However, since the bending strength and torsional strength of the branch rod itself is lower than that in the case where the branch rod is formed into a pipe shape as described in Publication of Utility Model Publication No. 55-36244, it is difficult to install the caster. Another problem was that the strength was weak.

The object of the present invention is to enable a caster to be reliably and firmly attached to a branch rod.

[Means to solve the problem]

In order to achieve this purpose, the present invention has a plurality of branch leg rods formed in the shape of a pipe with a rectangular or semicircular cross section by a bottom plate, left and right side plates, and a top plate, on a leg column extending in the vertical direction. and fixed to the lower surface of the tip of each branch rod so as to extend radially.
In a chair that is provided with casters having mounting bolts that protrude upward, a front opening hole is formed in the distal end surface of the branch leg rod and extends across the entire left and right width of the branch leg rod; A support member having an upwardly facing U-shaped cross section is tightly fitted inside the portion near the tip by inserting it through the front opening hole so as to be in close contact with the inner surfaces of the bottom plate and the left and right side plates of the branch leg rod, and A nut for the mounting bolt of the caster is fixed to the bottom plate of the support body, and a bolt insertion hole approximately concentric with the nut is bored in the bottom plate of the branch rod, so that the bottom plate of the support body and the branch rod are connected to each other. The bottom plate of the caster is fastened to the nut by screwing a mounting bolt of the caster into the nut, and a cover body for closing the front opening hole is attached to the tip of the branch rod.

[Functions and effects of the idea]

According to this configuration, the support body can be moved along the longitudinal direction of the branch rod, so that the bolt insertion hole in the branch rod may be misaligned along the longitudinal direction of the branch rod, or the nut may not be attached to the support body. Even if the mounting position is shifted along the longitudinal direction of the support, the screw hole of the nut can be aligned with the bolt insertion hole of the branch rod. By tightly fitting the support, the support will not come off even if the tip of the mounting bolt touches it, and it can be held in a state where it cannot rotate together with the mounting bolt, so simply attach the support to the branch rod. Even though it is only inserted inside, the caster mounting bolt can be securely screwed into the nut.

Therefore, according to the present invention, by moving the support body, the screw hole of the nut can be aligned with the bolt insertion hole of the branch rod, and the support body can be moved without having to hold each support body by hand. Since the mounting bolt of the caster can be screwed into the nut of the body, the caster can be reliably mounted to the branch rod.

Moreover, since the bottom plate of the branch rod and the bottom plate of the support body are fastened as one plate by the mounting bolt of the caster and the nut of the support body, the bottom plate of the branch leg rod and the bottom plate of the support body are mutually connected. By reinforcing each other, the bending strength can be significantly improved. In addition, the branch rod is pipe-shaped and has high bending strength and torsional strength, and the support body has a U-shaped cross section. It has strong strength against bending along the longitudinal direction of the branch rod, and also serves as a reinforcing member to prevent the branch rod from bending.
The mounting strength of the caster can be significantly improved, and the posture of the caster can be reliably prevented from changing due to deformation of the members after the caster is mounted.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

In the figure, reference numeral 1 indicates a leg device of a chair, and the leg device 1 includes a support rod 2 with a seat body (not shown) attached to the upper end, and a hollow shape into which the support rod 2 is fitted so as to be vertically slidable. The pedestal 3 includes a pedestal 3, and a plurality of branch rods 5 extending radially from the lower end of the pedestal 3 in plan view. A cover cylinder 4 is fixed to the pillar 3,
On the other hand, a caster 6 with a roller and a cover body 7 are provided at the tip of each of the branch rods 5.

The branch leg rod 5 is formed by bending a substantially rectangular metal plate so that one end surface and the other end surface thereof are joined, thereby forming a bottom plate 5b, left and right side plates 5c, 5c, and a top plate 5d.
The metal plate joint 5a is located at the bottom plate 5b, and the joints 5a are welded at appropriate intervals. The base end of each branch leg rod 5 is fixed to the outer surface of the large diameter portion 3a at the lower end of the pedestal 3 by welding.

A front opening hole 9 that is completely open over the entire cross-sectional area of each branch rod 5 is formed at the tip of each branch rod 5, and a top opening hole 10 that communicates with the front opening hole 9 is formed in the top plate 5d. While cutting out and forming the bottom plate 5
A bolt insertion hole 8 for the mounting bolt 6a of the caster 6 is bored in b.

Further, the cover body 7 has several ribs protruding from its front surface to improve its strength and aesthetic appearance, and the top plate 7a of the cover body 7 has sideways openings. forming an engagement groove 7b;
This engagement groove 7b is fitted into both left and right edges of the upper surface opening hole 10 of the branch rod 5, while the bottom plate 7c of the cover body 7 is fitted with the bottom plate 7c of the cover body 7. A locking hole 11 is formed so as to be concentric with the bolt insertion hole 8 of the branch rod 5. This locking hole 11 has a diameter larger than that of the support portion 6b at the base of the mounting bolt 6a of the caster 6.

In the hollow portion of the tip of the branch rod 5, the bottom plate 5b and the left and right side plates 5c of the branch rod 5,
A support 12 formed into a U-shaped cross section so as to be in close contact with the support 12 is inserted through the front opening hole 9 and fitted tightly, and a nut 13 is fixed to the upper surface of the bottom plate 12a of the support 12. By screwing the mounting bolt 6a of the caster 6 into the nut 13 from below through the locking hole 11 of the protective cover 7 and the bolt insertion hole 8 of the branch leg 5, the support part 6b of the caster 6 and the The bottom plate 5b of the branch rod 5 and the bottom plate 12a of the support body 12 are fastened together with the nut 13, thereby attaching the caster 6 to the branch rod 5.

In addition, as shown in FIG.
A horizontal flange 3b is formed at the upper end of the pillar 3, and a synthetic resin ring 16 with a skirt portion 16a is inserted upward through the upper surface of the horizontal flange 3b. Incapacitated,
The height of the seat body can be adjusted by screwing a set screw 18 with a lock into the nut 17 embedded in the ring body 16 and bringing the set screw 18 into contact with the inclined outer surface 2a of the support rod 2. I try to support them freely.

With the above structure, when installing the caster 6, the support 12 is inserted through the front opening hole 9 of the branch rod 5, and the support 12 is attached so that the screw hole of the nut 13 is connected to the branch rod 5. After aligning so that it is concentric with the bolt insertion hole 8 of , the cover body 7 is fitted onto the branch rod 5 from the front, and then the support hole 11 of the cover body 7 and the bolt insertion hole of the branch rod 5 are fitted. 8, the mounting bolt 6a of the caster 6 is screwed into the nut 13, and the bottom plate 5b of the branch rod 5 and the bottom plate 12a of the support body 12 are tightened together.

In this case, since the support body 12 is movable along the longitudinal direction of the branch rod 5, the nut 13 becomes concentric with the bolt insertion hole 8 regardless of machining errors of the support body 12 and the branch rod 5. Moreover, since the support body 12 is tightly fitted into the branch rod 5, the support body 12 cannot be rotated inside the branch rod 5 even if it is not held by hand. The front opening hole 9
The mounting bolt 6a can be reliably screwed into the nut 13 even when the cover body 7 covers the mounting bolt 6a.

Since the bottom plate 12a of the support 12 and the bottom plate 5b of the branch rod 5 are tightened together with the mounting bolts 6a and nuts 13, the bottom plate 12a of the support 12 and the bottom plate 5b of the branch rod 5 are bent. In addition to this, the branch leg rod 5 is pipe-shaped and has strong bending strength and torsional strength, and the support body 12 is U-shaped with an upward opening in cross section. The caster 6 can be firmly attached due to the combination of the following three factors: the strength against bending along the longitudinal direction of the branch leg rod 5 is significantly improved.

In addition, as shown by the dashed line in FIG. 1 and FIG.
After drilling a welding hole 14 of an appropriate diameter to expose the caster 6 to the branch rod 5, the inner circumference of the welding hole 14 is
The bottom plate 5b and the bottom plate 12a of the support body 12 may be integrally welded.

In this way, the connection between the support body 12 and the bottom plate 5b becomes even stronger, and the rigidity of the branch rod 5 can be further improved. In that case, since welding is performed with the caster 6 attached, it goes without saying that the reliability of attaching and removing the caster 6 is not impaired.

Further, the diameter of the locking hole 11 drilled in the bottom plate 7c of the cover body 7 is formed to be the same diameter as the through hole 8 of the bottom plate 5b of the branch leg 5, so that the bottom plate 7 of the cover body 7
b, the bottom plate 5b of the branch leg 5, and the bottom plate 12 of the support 12.
It is also possible to tighten all three together with a.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a diagram showing the main parts of the present invention.
The figure is a perspective view of the support strut, FIG. 3 is a negative view of FIG. 2, FIG. 4 is a negative cross-sectional view of FIG. 3, FIG. 5 is a negative cross-sectional view of FIG. FIG. 7 is a perspective view of the tip of the branch rod, FIG. 7 is a perspective view of the cover seen from below, and FIG. 8 is a cross-sectional view taken from FIG. 2. 1... Leg device, 3... Leg column, 5... Branch leg rod, 5
b...Bottom plate of the branch rod, 5c...Side plate of the branch rod, 5
d... Top plate of branch leg rod, 6... Caster, 6a...
...Mounting bolt, 7...Cover body, 8...Bolt insertion hole, 9...Front opening hole, 12...Support body, 12
a...Bottom plate of the support body, 12b...Side plate of the support body,
13...Natsuto.

Claims (1)

[Scope of utility model registration request] A plurality of branch leg rods 5 formed in a pipe shape with a square or semi-cylindrical cross section by a bottom plate 5b, left and right side plates 5c, and a top plate 5d are attached to a leg column 3 extending in the vertical direction.
In the chair, the caster 6 is fixed so as to extend radially in a plan view, and is provided with a mounting bolt 6a projecting upward on the lower surface of the tip of each of the branch legs 5. A front opening hole 9 that is open over the entire left and right width of the branch rod 5 is formed on the surface thereof, and a bottom plate 5b and left and right side plates 5c of the branch rod 5 are formed inside the portion near the tip of the branch rod 5.
A support 12 having an upwardly U-shaped cross section so as to be in close contact with the inner surface of the support body 12 is inserted through the front opening hole 9 and tightly fitted, and the mounting bolts 6a of the caster 6 are inserted into the bottom plate 12a of the support body 12. against Natsu 1
3 is fixed thereto, while a bolt insertion hole 8 is provided in the bottom plate 5b of the branch leg 5, which is substantially concentric with the nut 13.
, and fasten the bottom plate 12a of the support 12 and the bottom plate 5b of the branch rod 5 by screwing the mounting bolt 6a of the caster 6 to the nut 13, and the tip of the branch rod 5. A caster mounting device for a chair, characterized in that a cover body 7 that closes the front opening hole 9 is attached to the part.