Land vehicles – Wheeled – Stable vehicles – handle-propelled
Reexamination Certificate
1999-11-29
2002-06-25
Hess, Douglas (Department: 2169)
Land vehicles
Wheeled
Stable vehicles, handle-propelled
C188S020000, C188S029000
Reexamination Certificate
active
06409187
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to wheeled carts, such as a tool cart or the like, and more particularly to a brake system for arresting mobility of a cart and preventing indiscriminate rolling when left unattended.
User-propelled wheeled carts may present a hazard by becoming self-propelled when left unattended. The likelihood and magnitude of the hazard are increased when the cart is heavily loaded or positioned on an incline. To avoid potential damage which may result from inadvertent rolling, prior cart designs have included a braking device which secures and arrests the mobility of the cart when engaged, but which can be conveniently disengaged by the user when a need arises for the cart to be conveyed. One type of such a braking device is sometimes referred to as a “dead-man” switch.
The prior art has failed to produce a commercially acceptable braking mechanism or “dead-man” switch which provides safe and effective braking for wheeled carts, particularly tool carts. Prior braking mechanisms have taken on either a manually or automatically locking configuration. Manual braking systems are constructed in such a way that each wheel or caster is outfitted with its own self-contained braking mechanism, each being actuated and released from the individual wheel locations. In a manual system, the user must inconveniently move around the cart in order to actuate/release the individual braking mechanisms. Such a requirement is inefficient, cumbersome and time consuming, as well as presenting difficulties if the cart is positioned on an incline. The automatic braking systems typically employ a spring to engage or lock one or more of the cart wheels to arrest mobility. A manual brake actuator, usually a brake handle, is sometimes used to toggle between engaged and unengaged braking positions. Prior automatic braking systems exhibit certain drawbacks, including high cost and complexity, as well as being difficult to install, operate and maintain.
Machine shops or mechanical service shops commonly utilize tool storage cabinets or carts which include wheels or casters to allow the cart to be easily moved about the shop floor from job to job. These tool carts are often very heavy, commonly weighing over 300 pounds, and typically have a wheel or caster positioned at each corner of the cart. For such tool carts to be of practical use, they must be readily mobile and possess the ability to quickly and effortlessly overcome the momentum of the tool cart once the cart is positioned in a desired location, while also preventing inadvertent movement of the cart when left unattended.
The present invention attempts to remedy the inconveniences and drawbacks of prior braking mechanisms. The present invention provides a novel and unobvious brake system that can apply braking pressure to at least one cart wheel to arrest or inhibit movement of the cart, while allowing the operator to release the braking pressure when movement of the cart is desired.
SUMMARY OF THE INVENTION
The present invention relates generally to a brake system for a cart, such as a tool cart or the like. While the nature of the invention covered herein is to be determined with reference to the claims appended hereto, certain forms of the invention that are characteristic of the preferred embodiment are described briefly as follows.
According to one embodiment of the present invention, a cart includes a frame, at least two wheels attached to the frame, a braking mechanism, a brake release mechanism, and an actuator for actuating the brake release mechanism. The brake mechanism includes a lever arm coupled to the frame to allow pivotal movement about a pivot axis, with first and second portions of the lever arm disposed on opposite sides of the pivot axis. The lever arm has a braked position wherein the first portion is pressure-loaded against one of the cart wheels. The brake release mechanism includes a cam member coupled to the frame and disposed adjacent the second portion of said lever arm. The actuator is attached to the frame and is coupled to the cam member, such that actuation of the actuator rotates the cam member and causes the cam member to engage the second portion of the lever arm and pivots the lever arm to a released position wherein the first portion of the lever arm is disengaged from the cart wheel.
One object of the present invention is to provide a brake system for a wheeled cart that can apply sufficient braking pressure to at least one wheel to arrest or inhibit movement of the cart, while allowing the operator to release the braking pressure when movement of the cart is desired.
Related objects and advantages of the present invention will be apparent from the following description.
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FKI Industries Inc.
Gort Ed
Hess Douglas
Woodard Emhardt Naughton Moriarty & McNett
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