Cart and track arrangement

A cart and track arrangement includes a track unit having a straight track and a curved track, the straight track having an oblique bearing portion, the curved track having a horizontal bearing portion, and a cart having a cart frame and a wheel set, the wheel set having a wheel axle arranged in parallel to the oblique bearing portion of the straight track and a wheel pivotally mounted on the wheel axle, the wheel having a first tread disposed in parallel to the wheel axle for rotatably supporting on the oblique bearing portion of the straight track and a second tread for rotatably supporting on the horizontal bearing portion of the curved track. In an alternate form, the straight track has a horizontal bearing portion, the curved track has an oblique bearing portion, and the wheel has a first tread disposed in parallel to the wheel axle for rotatably supporting on the horizontal bearing portion of the straight track and a second tread for rotatably supporting on the oblique bearing portion of the curved track.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to cart and track technology and more particularly the arrangement between a cart and a track unit.

2. Description of the Related Art

In order to overcome the effect of a centrifugal force during turning of a cart on a track, the outer rail of the track is usually arranged at an elevation relatively higher than the inner rail around the turning point. However, the cart or cab will tilt when moving over the turning point.

To avoid the aforesaid tilting problem, a high-class cart may be equipped with a suspension system so that the cab can be kept in horizontal when moving over the turning point. However, this suspension system is complicated and quite expensive, not practical for use in an ordinary transportation cart.

Accordingly, there is a strong demand for a cart and track arrangement that eliminates the aforesaid problems.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a cart and track arrangement, which has a simple structural design and which enables the cart to be kept in horizontal when running in another direction, minimizing centrifugal force.

To achieve this and other objects of the present invention, a cart and track arrangement comprises a track unit and a cart. The track unit comprises a straight track and a curved track connected to the straight track curvedly. The straight track comprises an oblique bearing portion transversely downwardly sloping from one lateral side thereof at a predetermined angle and longitudinally extending along the length of the straight track. The curved track comprises a horizontal bearing portion longitudinally extending along the length thereof. The cart comprises a cart frame, and a wheel set mounted on the cart frame and rotatably supported on the track unit. The wheel set comprises a wheel axle, and a wheel pivotally mounted on the wheel axle. The wheel axle is arranged in parallel to the oblique bearing portion of the straight track. The wheel comprises a first tread disposed in parallel to the wheel axle for rotatably supporting on the oblique bearing portion of the straight track, and a second tread for rotatably supporting on the horizontal bearing portion of the curved track.

Further, the oblique bearing portion can be formed integrally with a part of the straight track of the track unit, or separately made and then detachably fastened to the straight track of the track unit.

Further, the cart comprises a spacer ring sleeved onto the wheel axle and stopped between the cart frame and the wheel of the wheel set to prohibit the wheel set from axial displacement.

Further, the spacer ring is disposed at a side of the wheel corresponding to a radially inward side of the curved track of the track unit.

Further, the rack unit comprises a guide roller bearing portion. Further, the cart comprises at least one guide roller rotatably supported on the guide roller bearing portion of the tack unit.

Further, the second tread is located at a side of the first tread corresponding to a radially inward side of the curved track of the tack unit.

Further, the second tread is located at a side of the first tread corresponding to a radially outward side of the curved track of the track unit.

In an alternate form of the present invention, a cart and track arrangement comprises a track unit and a cart. The track unit comprises a straight track and a curved track connected to the straight track curvedly. The straight track comprises a horizontal bearing portion longitudinally extending along the length thereof. The curved track comprises an oblique bearing portion transversely downwardly sloping from one lateral side thereof at a predetermined angle and longitudinally extending along the length of the curved track. The cart comprises a cart frame, and a wheel set mounted on the cart frame and rotatably supported on the track unit. The wheel set comprises a wheel axle, and a wheel pivotally mounted on the wheel axle. The wheel axle is arranged in parallel to the horizontal bearing portion of the straight track. The wheel comprises a first tread disposed in parallel to the wheel axle for rotatably supporting on the horizontal bearing portion of the straight track, and a second tread for rotatably supporting on the oblique bearing portion of the curved track.

Further, the oblique bearing portion can be formed integrally with a part of the curved track of the track unit, or separately made and then detachably fastened to the curved track of the track unit.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG. 1, a cart and track arrangement in accordance with a first embodiment of the present invention is shown comprising a track unit10and a cart30.

The track unit10comprises a straight track11, and a curved track13connected to the straight track11curvedly. The straight track11comprises an oblique bearing portion15transversely downwardly sloping from one lateral side toward the midline thereof at a predetermined angle and longitudinally extending along the length. The curved track13comprises a horizontal bearing portion17longitudinally extending along the length. Further, a guide roller bearing portion19is provided at the track unit10.

The cart30comprises a cart frame31and a wheel set33mounted on the cart frame31. The wheel set33comprises a wheel axle35and a wheel36pivotally mounted on the wheel axle35. The wheel axle35is arranged in parallel to the oblique bearing portion15of the straight track11. The wheel36comprises a first tread361disposed in parallel to the wheel axle35for rotatably supporting on the oblique bearing portion15of the straight track11, and a second tread362for rotatably supporting on the horizontal bearing portion17of the curved track13.

The cart30further comprises two guide rollers39respectively arranged at front and rear sides relative to the wheel36and rotatably supported on the guide roller bearing portion19of the track unit10to prohibit excessive lateral displacement.

The component parts of the present invention have further features as described hereinafter.

The oblique bearing portion15of the straight track11of the track unit10can be formed integral with the straight track11. Alternatively, the oblique bearing portion15can be separately made and then detachably fastened to the straight track11of the track unit10.

The cart30further comprises a spacer ring37sleeved onto the wheel axle35and stopped between the cart frame31and the wheel36of the wheel set33to prohibit the wheel set33from axial displacement.

Further, the spacer ring37is disposed at a side of the wheel36corresponding to a radially inward side of the curved track13of the track unit10.

The cart30further comprises a keyless axle bush38mounted in between the wheel axle35and the wheel36.

The operation of the first embodiment of the present invention is outlined hereinafter.

FIG. 3illustrates a running status of the cart30on the straight track11of the track unit10. As illustrated, the first tread361of the wheel36is kept in contact with the oblique bearing portion15of the straight track11of the track unit10and the wheel axle35of the cart30is kept in a tilted position, however the load-carrying surface32of the cart frame31is kept in horizontal.

When the cart30is moved curvedly away from the straight track11of the track unit10into the curved track13, as shown inFIG. 4, the second tread362of the wheel36is kept in contact with the horizontal bearing portion17of the curved track13of the track unit10and the wheel axle35of the cart30is kept in a tilted position, keeping the load-carrying surface32of the cart frame31in horizontal and minimizing centrifugal force.

FIGS. 5 and 6show a cart and track arrangement in accordance with a second embodiment of the present invention. As illustrated, the cart and track arrangement comprises a track unit10A and a cart30A.

The track unit10A comprises a straight track11A, and a curved track13A connected to the straight track11A curvedly. The straight track11A comprises a horizontal bearing portion15A longitudinally extending along the length. The curved track13A comprises an oblique bearing portion17A transversely downwardly sloping from one lateral side toward the midline thereof at a predetermined angle and longitudinally extending along the length.

The cart30A comprises a cart frame31A and a wheel set33A mounted on the cart frame31A. The wheel set33A comprises a wheel axle35A and a wheel36A. The wheel axle35A is arranged in parallel to the horizontal bearing portion15A of the straight track11A. The wheel36A comprises a first tread361A disposed in parallel to the wheel axle35A for rotatably supporting on the horizontal bearing portion15A of the straight track11A, and a second tread362A for rotatably supporting on the oblique bearing portion17A of the curved track13A.

According to this second embodiment, the cart30A also comprises a spacer ring37A and a keyless axle bush38A arranged in the same way as the like parts in the aforesaid first embodiment.

This second embodiment further comprises a guide roller bearing portion19A provided at the track unit10A, and two guide rollers39A arranged on the cart30A at front and rear sides relative to the wheel36A and kept in contact with the guide roller bearing portion19A to prohibit the cart30A from excessive lateral displacement.

The operation of this second embodiment of the present invention is outlined hereinafter.

FIG. 5illustrates a running status of the cart30A on the straight track11A of the track unit10A. As illustrated, the first tread361A of the wheel36A is kept in contact with the horizontal bearing portion15A of the straight track11A of the track unit10A; the wheel axle35A of the cart30A is kept in horizontal; the load-carrying surface32A of the cart frame31is kept in horizontal.

When the cart30A is moved curvedly away from the straight track11A of the track unit10A into the curved track13A, as shown inFIG. 6, the second tread362A of the wheel36A is kept in contact with the oblique bearing portion17A of the curved track13A of the track unit10A and the wheel axle35A of the cart30A is kept in a horizontal, minimizing centrifugal force.

The oblique bearing portion17A of the curved track13A of the track unit10A can be formed integral with the curved track13A. Alternatively, the oblique bearing portion17A can be separately made and then detachably fastened to the curved track13A of the track unit10A.

Further, the spacer ring also can be disposed at a side of the wheel corresponding to a radially outward side of the curved track of the track unit, or the cart comprises two spacer rings disposed at two sides of the wheel respectively.

Still further, either the second tread can be located at a side of the first tread corresponding to a radially inward side of the curved track of the track unit, or the second tread can be located at a side of the first tread corresponding to a radially outward side of the curved track of the track unit.

In conclusion, the invention provides a cart and track arrangement, which has a simple structural design and which enables the cart to be kept in horizontal when running in another direction, minimizing centrifugal force.