Jib Crane

Abstract

This invention relates to a jib crane characterized by the fact that the top of the jib is pivoted to the main post, which travels on a single rail and the wheels at the bottom of the jib travel on an annular flange fitted around the main post.

Description

SUMMARY OF THE INVENTION

This invention relates to a jib crane. The object of this invention is to provide a jib crane traveling on a single rail and having a load supporting member which may be swung through an angle of 360.degree..

A conventional jib crane travels on two rails and the jib is pivoted to swing freely about the main post. Since it needs two rails, its installation takes up a great deal of space; it cannot swing through 360.degree.; and it has a complicated mechanism.

These disadvantages are overcome by my invention, a preferred embodiment of which is illustrated in the accompanying drawings, in which:

FIG. 1 is a side view of a jib crane according to my invention;

FIG. 2 is a sectional view taken along the line II--II of FIG. 1;

FIG. 3 is a partial longitudinal sectional view of the swingable part of the jib;

FIG. 4 is a sectional view taken along the line IV--IV of FIG. 3;

FIG. 5 is a side view of the traveling part; and

FIG. 6 is a sectional view of the hoist supporting beam.

Referring now to FIG. 1, it will be seen that my crane comprises a single supporting rail 1 and a single guide rail 2 parallel to and above this rail. In the drawing, this guide rail is shown with a C-shaped section.

As seen on FIGS. 1 and 5, a base frame 3 equipped with wheels 4, which roll on the rail 1, and with two rollers 6 which contact both sides of the vertical web of this traveling rail 1 is mounted upon the supporting rail 1. The rollers 6 have a narrow stepped upper portion 6', best seen in FIG. 5. The lateral edges of the upper part of the rail are gripped between the stepped portions 6' and the lower surfaces of this upper part engage the wider portions of the rollers. The wheels 4 of the base frame 3 roll on the rail 1 and are driven by a motor 5 on the frame 3.

The main post 7 stands upright on the base frame 3. From the top end of the main post 7 projects a pin 8, at the top of which is rotatably mounted a roller 9, which engages the groove in the above-mentioned guide rail 2.

As seen in FIGS. 3 and 4, the main post 7 carries an annular flange 10. The upper end of the base of the jib 12 is pivotally mounted by means of the bearing 11 on the pin 8 at the top of the main post. The wheels 13 attached to the lower part of the base of the jib 12 contact the annular flange 10 of the main post. These wheels are mounted on the same shaft as the large gear 15 driven by the motor 14. Therefore, when the motor 14 runs, its motion is transmitted to the wheels, which, guided by the annular flange 10, travel, together with the jib 12, around the main post. The arrangement is more stable, when there are two wheels which contact the annular flange 10. In FIG. 3, 16 is a plate which serves both as the stand for the motor 14 and as a bearing and this plate is fixed to the jib 12. An adequate number of rollers 17 (FIG. 6) are longitudinally spaced along the jib 12 and arranged oppositely in two rows. These rollers 17 engage guide frames 19 having an approximately C-shaped section which are welded to the low sides of the main beam 18 which guides the hoist. Further, pulleys 20, 21 are attached to the tip and base of the jib 12 and between these pulleys is stretched an endless wire rope 22 or the like, one part of which is attached at 23 to the main beam 18. When these pulleys 20, 21 are properly rotated, the main beam 18 is moved toward or away from the main post 7. The hoist 24 is attached to the main beam 18 and can travel freely on the beam 18.

Such being the composition of the jib crane of this invention, the jib crane can travel on the rail through an angle of 360.degree. to lift or move a desired load easily.

As the jib crane of this invention needs only a single traveling rail, it takes less space for installation than a conventional one which needs two rails. Moreover, since the wheels 4 of the base frame of the main post contact the upper surface of the rail 1 and the rollers 6, contact the underside of the upper part of the rail 1 and its vertical web, the crane is not likely to get derailed, regardless of the direction from which the load is applied to the crane. Since the base of the jib rotatably supports the upper part, and the lower part, being supported by rollers, can turn along the annular flange of the main post as a guide, the jib can swing very smoothly up to 360.degree..

Claims

What is claimed is:

1. A jib crane comprising:

a single supporting rail comprising a vertical web and a transverse upper part wider than said web;

a guide rail parallel to and above said supporting rail;

a base frame supported by wheels which roll on said supporting rail and carrying two rollers which grip opposite sides of said supporting rail, said rollers being stepped to simultaneously contact both said web and the lower surface of said transverse part;

a main post which stands upright on said base frame, and has an upper end engaging said guide rail;

a transverse annular flange carried by said post; and

a jib having vertically spaced parts pivoted to said main post, carrying a motor and wheels driven by said motor which travel on said annular flange.

2. A jib crane as claimed in claim 1 in which said jib comprises a box frame, and an I-beam suspended from said box-frame and longitudinally slidable relative to said box-frame, said beam carrying a hoist suspended from rollers and mounted to travel along said beam.