Grounding Floor Glide for Shelving, Chairs, and Equipment to Reduce Risk from ESD (Electro-Static Discharge) and Protect Floors from Damage
This conductive ESD protective foot is a grounding device consisting of a resilient conductive floor glide (foot) that provides an electrical path from a shelving unit, chair, or other equipment, to a conductive floor. The foot can be installed onto a leg leveling bolt or, alternatively, inserted into the shelf post itself. This foot provides an electrical connection for ESD purposes while it allows a device using this foot to be moved without causing damage to the floor. This device provides a conductive path to the floor, allows a shelving unit to slide more easily across a floor without damage and separates metal leg levelers (bolts) from the floor, which reduces risk from rust stains caused my metal legs rusting to the floor from use of water or cleaning methods This Foot protective foot can be installed and removed without the use of tools and is held securely in place when attached. It allows for some variation in bolt-head size as well as post inside diameter, which increases its flexibility, as the Heavy-Hex bolts used as leg levelers have bolt-heads that often vary depending upon the manufacturer. If an electrically conductive version is not required, non-conductive material can be substituted to reduce cost.
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SEQUENCE LISTINGNone.
FIELD OF THE INVENTIONThis invention relates to electrostatic discharge (ESD) and in particular, the grounding of shelving, chairs, and equipment to conductive floors while protecting the appearance of floors from scratches and rust stains caused by leveling legs and posts.
DESCRIPTION OF THE PRIOR ARTConventional shelving units typically include a plurality of vertically standing support posts and at least one shelf horizontally supported by the posts. For example, U.S. Pat. No. 3,523,508, issued to Maslow 1972, and U.S. Pat. No. 3,757,705, issued to Maslow 1970, disclose a shelving unit formed from four support posts, and one or more horizontal shelves provided with a frustro-conically shaped collar at each corner for receiving one of the support posts. A split sleeve is secured to each support post and fits into the frustro-conically shaped collar at each corner of the shelf. The positions of the split sleeves on the support posts are vertically adjustable so the height and relative spacing of the horizontal shelves can be chosen when assembling the shelving structure. These adjustable shelving structures are sold and marketed under the trademark SUPER ERECTA SHELF by InterMetro Industries Corporation, of Wilkes-Barre, Pa. Other similar adjustable shelving structures are offered under brand names such as Eagle and others.
Each post 1 is typically configured with a leveling leg 3 at the base 1-B of the post 1, but, in the absence of a leveling leg 3, the post 1 is sometimes placed directly on a floor, with surface 1-B contacting the floor. The leveling legs 3 typically consist of a galvanized or chrome plated heavy-hex bolt. The height of each of leg leveler 3 can be adjusted to various heights by means of the distance the leg leveler is threaded into the threaded adaptor 2. Although the diameter and thread pitch is consistent, the head size of the heavy-hex bolt 3 varies depending upon the manufacturer.
Static electricity is commonly defined as an electrical charge resulting from the imbalance of electrons on the surface of a material. Most people are quite familiar with the everyday effects of static electricity—it is the shock one receives when touching a doorknob after walking across a carpet. The technical name for the electrical shock just described is electrostatic discharge (ESD). ESD is technically described as the transfer of electrical charge between bodies—for instance, a human hand and a doorknob—that are at different electrical potentials.
In most everyday situations, ESD can be a bother but rarely a problem. However, the problems resulting from ESD are magnified in industrial settings, where ESD is a major concern. Among the many problems that static discharge can cause are the unintentional ignition of flammable materials, damage to electronic components and systems, and the attraction of contaminants such as charged dust particles in clean room environments. Even centuries ago military forces were aware that ESD could cause the unintentional ignition of black powder. To alleviate this sometimes-catastrophic problem, ESD control measures were used as early as the 14th century to protect black powder stores. Today, many industries—from high tech manufacturing plants to businesses commonly thought of as “smoke stack” industries—are concerned with ESD and its control, since controlling ESD can lead to a safer work environment and reduction or elimination of damage resulting from ESD.
While nearly all industries are or should be concerned with controlling ESD, the concern is most acutely felt by businesses in the electronics industry.
To give just a few examples of the damage that ESD can cause in the electronics industry, it can destroy or degrade semiconductor devices by changing operational characteristics. It can cause disruptions to the normal operation of an electronic system—sometimes leading to equipment failure, and in clean rooms it can cause charged particles to adhere tightly to the surface of a silicon wafer, resulting in distinct problems with wafer production and efficiency.
Given these problems and the economic damage that can result from them, control of ESD is a major concern and a complete industry has grown up around the field of ESD control.
Some very common ESD protective measures are to use conductive floors, benches, containers, storage shelves, and transport carts and then connect each of these, as well as products and people, to a common electrical ground. Connecting them to a common electrical ground reduces any build-up of electrical potential between objects, thereby reducing the risk of an ESD event.
A critical component of an ESD control program is dissipating and neutralizing ESD during handling, transporting and storing of ESD sensitive materials.
A common type of shelving unit and transport cart used in the electronics and other industries is a type of wire shelving shown in
Shelving units such as those in
Floors in many electronics manufacturing facilities are typically a special electrically conductive vinyl tile, conductive epoxy, conductive urethane, or other appropriate material. A majority of these floors that are white or light gray and are not only functional, but also provide a clean and professional appearance.
Sliding a shelving unit across a floor typically causes floor damage due to the leg leveler bolt-head or the end of a post digging into the floor. The heavy hex bolts used as leg levelers and the posts themselves rust due to floor cleaning solutions and leave rust stains on the floor. Various floor protectors (floor slides) are available, but they are typically made from insulative material, and there are no electrically conductive floor slides that can be installed both on the leg levelers (see
The present invention is an electrically conductive leg leveler (foot) 10 that easily installs onto a leveling leg 3 of a shelving unit, chair, or equipment, as shown in
Objects and Advantages:
Besides the objects and advantages of the electrically conductive foot 10 described in the above patent, several objects and advantages of the present invention are:
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- (a) Easy to install onto existing leg levelers 3
- (b) Can be Installed by inserting directly into posts without leg levelers
- (c) Installs onto leg leveler bolt-head of various sizes due to the friction-fit and lead-in of surfaces 10-A and 10-C, and corner relief 10-B
- (d) Installs on leveling legs for chairs and other various furniture
- (e) Effective on other types of surfaces besides conductive floors
- (f) Reduces damage caused by metal leg levelers or posts rusting to floor
- (g) Provides a conductive path for electrical ground to a conductive floor for ESD purposes
- (h) Allows the shelving unit to slide across the floor without causing damage
- (i) Leveler 3 can be adjusted with a wrench using the hex surfaces 10D on the outside of foot 10
- (j) Will not stick to the floor or stain the floor like rubber feet
The preferred embodiment of ESD protective foot 10 is shown in
Foot 10 is made of any sufficiently strong, electrically conductive, resilient, corrosion resistant, and flexible material such as a conductive plastic, conductive rubber, stainless steel, or other similar material.
Foot 10 is typically installed in one of two configurations. The first configuration is the external position, as shown in
Allowance for variation the head size of the Heavy-Hex bolt used as a leveling leg 3 is provided by two features. The first feature is pressure on flat surfaces 3-A of the hex bolt are held in place by foot inside contact points 10-A The second feature that allows size variation is the hex bolt corner relief 10-B, which accommodates variation of hex bolt 3 points 3-B and.
Claims
1. A rust-proof floor glide providing a means of electrical interconnection between a shelving post leveling leg and a conductive floor that can be installed by installing onto the leg leveler or by directly inserting said floor glide directly the into post consisting of:
- a. An electrically conductive glide
- b. Optionally can be constructed with insulative material
- c. A means of urging said electrically conductive glide against said leveling leg bolt of various size head dimension
- d. A means of retaining the electrically conductive floor glide of said shelving unit leveling leg of various size head dimension
- e. A means of urging the electrically conductive floor glide against said post
- f. A means of retaining the electrically conductive floor glide inside of said shelving unit post
- g. Optionally may be fitted to other items such as chair legs
Type: Application
Filed: Jan 18, 2021
Publication Date: Jul 21, 2022
Inventor: Scott Randall Newman (Beaverton, OR)
Application Number: 17/151,626