Conductive caster wheel

A conductive caster wheel is adapted to be mounted on a cart. The conductive caster wheel includes a caster hub adapted to be sleeved on a bearing of the cart, a wheel body sleeved on the caster hub, and a conductive plate disposed inside the caster hub and the wheel body. The conductive plate has an inner conductive section and an outer conductive section. The inner conductive section is exposed from an inner surrounding surface of the caster hub, and is adapted to be electrically connected to the bearing. The outer conductive section is electrically connected to the inner conductive section, is exposed from an outer surrounding surface of the wheel body, and is adapted to be in contact with a ground surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Taiwanese Invention Patent Application No. 109146702, filed on the 29 Dec. 2020.

FIELD

The disclosure relates to a wheel, and more particularly to a conductive caster wheel.

BACKGROUND

Static electricity may discharge and cause damage to electronic equipment, and is therefore a major concern for electronics manufacturing facilities. Workers at these facilities are required to wear electrostatic discharge (ESD) equipment such as anti-static ESD wrist straps while handling electronic components. This type of ESD wrist strap usually has a clip for connecting to a ground conductor and works by dispersing the static electricity on the worker to the ground. Additionally, the workers may use carts and trolleys to transport the manufactured electronic components within the facility, and the electronic components will need to be protected against ESD when being transported. Consequently, the carts used at the electronics manufacturing facilities are conventionally designed with a grounding line near the cart handle to mitigate ESD. However, this design is inconvenient for the workers, and the cart may not always be electrically grounded due to worker neglect or other factors, so that the electronic components transported by the cart may be damaged by electrostatic discharge.

SUMMARY

Therefore, an object of the disclosure is to provide a conductive caster wheel that can alleviate at least one of the drawbacks of the prior art.

According to the disclosure, a conductive caster wheel adapted to be mounted on a cart. The conductive caster wheel includes a caster hub adapted to be sleeved on a bearing of the cart, a wheel body sleeved on the caster hub, and a conductive plate disposed inside the caster hub and the wheel body. The conductive plate has an inner conductive section and an outer conductive section. The inner conductive section is exposed from an inner surrounding surface of the caster hub, and is adapted to be electrically connected to the bearing. The outer conductive section is electrically connected to the inner conductive section, is exposed from an outer surrounding surface of the wheel body, and is adapted to be in contact with a ground surface.

DETAILED DESCRIPTION

Referring toFIGS.1,2and3, an embodiment of a conductive caster wheel200is shown. The conductive caster wheel200is adapted to be rotatably mounted on a metallic bearing901of a cart900so that the cart900can be electrically grounded. The conductive caster wheel200includes a caster hub3adapted to be sleeved on the bearing901of the cart900, a wheel body4sleeved on the caster hub3, and a conductive plate5disposed inside the caster hub3and the wheel body4.

In this embodiment, the caster hub3is made of a plastic material and surrounds a central axis (A), and the wheel body4is made of a plastic material and is solid. The caster hub3and the wheel body4are made by molding and are molded as one piece. However, the method and material used to manufacture the caster hub3and the wheel body4is not limited to the above.

The conductive plate5is made of an electrically conductive metallic material, and is embedded inside the caster hub3and the wheel body4. The conductive plate5has an inner conductive section51and an outer conductive section52. The inner conductive section51is exposed from an inner surrounding surface of the caster hub3, and is adapted to be electrically connected to the bearing901. The outer conductive section52is electrically connected to the inner conductive section51, is exposed from an outer surrounding surface of the wheel body4, and is adapted to be in contact with the ground surface.

The inner conductive section51has an inner covered portion511that is embedded in the caster hub3, and an inner ring portion513that is electrically and transversely connected to the inner covered portion511, that extends along the central axis (A), that is exposed from the inner surrounding surface of the caster hub3, and that is adapted to be electrically connected to the bearing901. The inner covered portion511of the inner conductive section51has a plurality of through holes512that extend parallel to the central axis (A), and the through holes512are filled with a portion of the caster hub3. The inner covered portion511of the inner conductive section51is ring-shaped and is co-axial with the caster hub3, the ring portion513is connected to an inner end of the inner covered portion511, the caster hub3is enclosing the inner ring portion513, and the inner ring portion513is flush with the inner surrounding surface of the caster hub3.

The outer conductive section52has an outer covered portion521that is embedded in the wheel body4, and that is electrically connected to the inner conductive section51. The outer conductive section52further has a peripheral rim portion523that is electrically and transversely connected to the outer covered portion521, that extends along the central axis (A), and that is exposed from the outer surrounding surface of the wheel body4, so that it may be in contact with the ground surface when the wheel body4rolls.

The outer covered portion521of the outer conductive section52is ring-shaped and is co-axial with the wheel body4. The peripheral rim portion523is connected to an outer end of the outer covered portion521. The outer covered portion521has a plurality of through holes522that extend parallel to the central axis (A), and the through holes522are filled with a portion of the wheel body4.

When assembling the cart900, the caster hub3is sleeved onto the bearing901so that the conductive section51of the conductive plate5is in contact with the bearing901. The bearing901is then mounted on an axle902of the cart900. The cart900may have a plurality of axles902corresponding to the amount of conductive caster wheels200that are to be mounted to the cart900. The axles902of the cart900are made of a conductive metal material so that, when the conductive caster wheels200are mounted to the cart900, the cart900is able to stay grounded.

When a worker in an electronics manufacturing facility employs the cart900, he/she may clip his/her ESD wrist strap to any area on the cart900that is made from conductive metal and electrically connected to one of the conductive caster wheels200, or he/she may handle the cart900directly with his/her hands touching any of the conductive metal parts of the cart and any static electricity on the worker and the cart900can be conducted to the ground and discharged.

Referring toFIG.4, another embodiment of the conductive caster wheel200according to this disclosure is shown. In this embodiment, the inner ring portion513of the inner conductive section51and the peripheral rim portion523of the outer conductive section52of the conductive plate5are omitted. Instead, the inner end of the inner covered portion511is in direct contact with the bearing901, and the outer end of the outer covered portion521is in direct contact with the ground surface. Furthermore, the materials used to manufacture the wheel body4and the conductive plate5may be carefully selected to have the same rate of wear, so that the conductive plate5and the wheel body4will be worn away by the ground surface at the same rate.

Additionally, in this embodiment, the through holes512and the through holes522of the conductive plate5are round. However, this is not a limitation this disclosure and the through holes512,522may be other shapes.

In summary of the above, the conductive caster wheel200according to this disclosure is able to remain electrically grounded when the cart900is in use, by virtue of the conductive plate5being disposed inside the caster hub3and the wheel body4. Therefore, the object of this disclosure is satisfied.

While the disclosure has been described in connection if with what are considered the exemplary embodiments, it is understood that this disclosure is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.