|Publication number||US3912973 A|
|Publication date||Oct 14, 1975|
|Filing date||Jan 14, 1974|
|Priority date||Jan 14, 1974|
|Also published as||CA1031816A, CA1031816A1|
|Publication number||US 3912973 A, US 3912973A, US-A-3912973, US3912973 A, US3912973A|
|Inventors||Young David Arthur|
|Original Assignee||Young David Arthur|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (10), Classifications (9)|
|External Links: USPTO, USPTO Assignment, Espacenet|
' United States Patent Young Oct. 14, 1975 CONDUCTIVE HUMAN ELECTRICAL TERMINAL  Inventor: David Arthur Young, 1 130 Surrey,
Glen Ellyn, 111. 60137  Filed: Jan. 14, 1974  Appl. No.: 433,213
 US. Cl 317/2 B  Int. Cl. HOSF l/00; HOSF 3/02  Field of Search 317/2 B  References Cited UNITED STATES PATENTS 2,287,744 6/1942 Monahan 317/2 B 3,281,624 10/1966 Patchen..... 317/2 B 3,459,997 8/1969 Legge 317/2 B Primary ExaminerL. T. Hix Attorney, Agent, or Firm-Alter and Weiss ABSI'RACT A slip-on conductive rubber boot 0r overshoe has toe, heel and side sections which come up over a workers shoe far enough to insure a good electrical contact between the human wearing the boot or overshoe and ground, regardless of the body position. An integral conductive rubber strap extends from the boot or overshoe upwardly toward a garter for encircling the leg above the calf. A comfortable connector on the garter insures the snug, but not tight fit of the garter. There are no snaps to unsnap, no buckles to dig in, no loose parts to become lost.
4 Claims, 7 Drawing Figures CONDUCTIVE HUMAN ELECTRICAL TERMINAL This invention relates to electrical terminals for the human body and more particularly to safe, reliable, and comfortable means for maintaining a desired body potential.
There are many times when and places where it is desirable to maintain a certain body potential, usually a ground potential. For example, persons moving through an explosive laden atmosphere (such as a hospital operating room filled with ether fumes) often wish to maintain a body ground potential and thereby avoid static electricity sparks. Some medical treatment may involve an application of electrical currents to the body. Workers in intense electrical fields, such as extremely high voltage power line towers, must be grounded at all times for their safety. Those familiar with the field will readily perceive many other times and places when a human terminal is either necessary or desirable.
For example, a worker on a high voltage tower is in an extremely high voltage field wherein his ungrounded body would receive ambient energy in a volume and level comparable to the energy that is consumed by a soldering iron. His body coupling into this electrical environment is capacitive, and therefore, this energy is accumulated as a charge on his body, much as a charge is built upon a capacitor. When the charging energy reaches a sufficient level, there is a discharge in the nature of a static electric are between the body and ground. The body effect produced by such discharge is most difficult to predict. There could be a muscular spasm causing a part of the body to jerk, which could result in a fall or the touching or clutching of a high voltage source; or, the heart muscle could be affected to cause death.
The body charge will not build up if the body is held at the potential of the system ground. Accordingly, it is common practice for people in this kind of environment to wear conductive boots or overshoes which form ground terminals for the body. These ground terminals must maintain a continuous contact with the system ground, at all times. Therefore, the best boots or overshoes are those which make good contact regardless of how the worker moves, whether he is standing or lying prone, on his face, back or side. Also, since the worker climbs over tower struts, bolt heads, screw ends, and the like, the boots or overshoes must resist snagging and tearing which would reduce reliability.
Usually, the boots or overshoes are electrically connected directly to the workers body so that the skin potentials will flow off the body and onto the boots or overshoes. Often the body contacts are garters around an arm or leg, or a belt around the waist. These garters or belts must make good skin contact, yet they must be comfortable. If the garter or belt is too tight, it could cut off circulation. If too loose, it could make an inefficient electrical contact with the body. If there are snaps or buckles, they could come unsnapped, dig into the body, or otherwise become very uncomfortable.
Accordingly, there is a need for a-conductive boot or overshoe which resists wear, tear and other similar damage, which is comfortable to use and which maintains contact with ground, regardless of the workers body position.
Therefore, an object of the invention is to provide new and improved body terminals. Here an object is to provide conductive boots or overshoes which are easy to put on or take off over normal workers boots or shoes. Another object is to provide conductive boots or overshoes having integral body contacts which are positive in operation and comfortable in use. Still another object is to provide conductive boots or overshoes which are free of loose parts that might tend to unsnap or become lost.
Another object is to provide conductive boots' or overshoes of a shape and design which is always in contact with a ground surface despite many changes in body position.
Still another object of the invention is to provide conductive boots or overshoes which are less likely to become torn or otherwise damaged from contact with towers, struts, bolt heads or the like.
In keeping with an aspect of this invention, these and other objects are accomplished by providing a slip-on conductive rubber boot or overshoe having an arch strap to help secure it in place. The toe, heel and sides of the boot or overshoe come up over a worker's shoe far enough to insure a good electrical contact between the boot or overshoe and ground regardless of the workers body position. An integral strap of conductive rubber extends from the boot or overshoe upwardly. It terminates in a garter for encircling the leg above the calf. A special mechanical connector on the garter insures a snug, but not tight, comfortable fit, without the possibility that the garter will come unfastened. There are no snaps to unsnap, no buckles to dig in, no loose parts to become lost.
The nature of a preferred embodiment of the invention will become more apparent from a study of the attached drawings wherein:
FIG. 1 is a perspective view of the inventive boot or overshoe as worn by a worker;
FIG. 2 is a plan view of the boot or overshoe with the integral extension and garter;
FIG. 3 is a cross-sectional view of FIG. 1 taken along line 33 thereof, showing how the boot or overshoe follows the contours of the shoe, toe, sole and heel;
FIG. 4 is a fragmentary view of the tread pattern on the bottom of the boot or overshoe; and
FIGS. 5-7 are three stop motion views showing the use of the fastener attached to the garter.
In greater detail, the inventive boot or overshoe 20 comprises a toe cap 21, a heel section 22 and an arch strap 23, integrally interconnected by side members 24, 25 and sole 26. The toe cap 21 raises from the sole and covers a sufficient area on the top and sides of the worker's toes to insure a good contact with ground regardless of how the worker lies on his stomach or bends his ankle. Likewise, the heel section 22 comes up around the back and heel sides of the workers heels with similar effect when the worker lies on his back. The side panels 24, 25 integrally interconnect toe cap 21 and heel section 22 for making a similar contact with ground, while the worker is lying on his side. From this, it should be apparent that, regardless of the workers body position, the boots or overshoes on his feet are always in good electrical contact with the ground, at all times.
The boots or overshoes are shaped and dimensioned to resist wear, tearing and the like; yet they are easy to slip on or remove. More particularly, as best seen in FIG. 3 the boot or overshoe fits over the workers regular shoe or boot snugly enough to resist bagging or wrinkling while being worn. The heel area 30 of the boot or overshoe comes up and around the heel 31 of the workers regular shoe or boot 32 to preclude any looseness in the instep area, where a bolt head might otherwise catch loose material. The ankle strap 23 easily slips on over the arch of the foot, and yet it also pulls the side walls 24, 25 up tightly against the shoe.
From FIGS. 1, 3 and 4, it is seen that the tread design 32 of the boot or overshoe sole is sufficiently thick to resist wear. It is shaped to guide the contact area of the foot over or around bolt heads 33, nuts, struts and the like whereby minor obstacles fit into spaces 35 in the tread, between the fins 36, 37.
Integrally molded with the boot or overshoe is an extension member 38 which raises from the boot or overshoe toward the workers knee. At the top of extension 38 is a leg encircling garter 40 shaped and dimensioned to fit around the leg in the area lying generally between the knee and calf. This garter fits against the workers skin to make good body contact.
The coupler on the garter is a reliable device which insures a snug fit around the leg, without being too tight. This is important since the snug fit insures good electrical contact with the body, while the not too tight fit insures continued blood circulation.
FIGS. -7 show how the coupler is designed and operated-One end 41 of the garter 40 includes a series of belt holes 46 spaced from each other by distances which enable a worker to select a comfortable length. The other end 47 of the garter has an upstanding post 48 formed in three sections. Section 49 is a somewhat rod-like member which fits through a hole 46 and projects far enough on the other side of garter 40 for a worker to grip and pull it. The next post section 50 is conical and shaped to guide the selected hole 46 into a stretched configuration. The soft conical rubber of section 50 tends. to compress somewhat as the hole stretches around it. The last section 51 on post 48 is approximately the same diameter as the hole 46. Therefore, the belt hole tends to snap around section 51.
Thus, to attach the garter, the worker selects a belt hole and projects the rod end 49 through it (FIG. 5). Then he grips end 49 and pushes the belt hole 46 down over the conical section 50 (FIG. 6). Finally, he snugs the belt end with the selected hole 46 captured under the flared end of conical section 50 (FIG. 7).
The garter is now in place. The garter is tight enough to insure good electrical contact without interfering with the workers circulation. The positive catch around conical section 50 will not easily come unfastened, but can be released by pulling garter end 41. There'are no buckles to dig into the workers leg. There are no loose parts to come unsnapped and be lost.
The entire unit may preferably be made from a simple molded piece of conductive rubber.
While different conductive elastomers may be used to make the boot or overshoe, I prefer to use one known by the American Society of Testing and Measurements Code number 4AA625A13B1'3C12. Of these codes: 4AA is a compounding number, 625 refers to 60 durometer and 2500 pounds per square inch tensile strength; A13 refers to a heat age; 813" refers to a l6 percent compression; and C12 refers to ozone resistance. This coded information is summarized in the following'table.
Durometer 60 Tensile 2500 PSI (min) Elongation 400% Oven Aged 96 hrs. at 158F ASTM-D-573 at 3l0 (3C) Durometer Change +IO Tensile Change -l5% (max) Elongation Change 20% Compression Set 22 hrs.
l58F ASTM-D-395 Method B 25% Ozone 72 hrs. at SOPPHM at lO0F ASTM-D-l l7l & AT8310 (2-E) 0" Rating Those skilled in the art will readily perceive modifications and improvements; therefore, the appended claims are to be construed to cover all equivalents falling within the scope and spirit of the invention.
1. A conductive electrical terminal comprising a slipon conductive boot or overshoe,
said boot or overshoe having a conductive sole, toe
vamp, heel vamp and side vamp sections,
said toe vamp section comprising toe vamp cap,
said toe vamp cap having a horizontal portion covering the top from section of the users shoe,
said heel vamp section comprising a member which comes up around the back and sides encircling the heel of a shoe, and the side vamp section rising above the sole and welt sections of the users shoe, whereby said vamp sections come up over the users shoe far enough to insure a good electrical contact between the boot or overshoe and ground regardless of the users body position,
an integral conductive strap means extending from the heel area of the boot or overshoe upwardly,
a garter integrally and electrically connected to said strap for encircling the leg of the user below the knee and above the calf,
mechanical connector means on the garter to insure a snug, but not tight, comfortable fit around the users leg without requiring tying,
one end of the garter includes a series of belt holes spaced from each other by distances which enable a user to select a comfortable length,
the mechanical connector on the garter is an upstanding post on the other end of the garter,
said post being formed in three sections,
one section being a somewhat rod-like member which fits through a hole and projects far enough on the other side of the garter for a worker to grip and pull it,
the next post section being conically shaped,
the last section being a post approximately the same diameter as a hole, and
said boot or overshoe strap and garter being free of snaps, buckles and loose parts.
2. The terminal of claim 1 wherein said conductive boot or overshoe and strap are a single integral member made of conductive rubber.
3. The terminal of claim 2 wherein the conductive rubber has the following characteristics:
Durometer 60 Tensile 2500 PSI (min) Elongation 400% Oven Aged 96 hrs. at 158F ASTM-D-573 at 3l0 (3C) Durometer Change +l0 -Continued Tensile Change Elongation Change Compression Set 22 hrs.
158F ASTM-D-395 Method B Ozone 72 hrs. at SOPPHM at lF ASTM-D-l l7l & AT83l0 (2-E) -l5% (max) "0" Rating.
into spaces in the tread.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2287744 *||Oct 8, 1941||Jun 23, 1942||Donnell Shoe Company O||Conductive footwear|
|US3281624 *||Jul 22, 1963||Oct 25, 1966||Stephen I Patchen||Electrically conductive elastomeric composite|
|US3459997 *||Aug 15, 1967||Aug 5, 1969||Legge Walter G||Body grounding device|
|Citing Patent||Filing date||Publication date||Applicant||Title|
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|US5184275 *||Dec 21, 1989||Feb 2, 1993||Hughes Aircraft Company||Heel grounding device|
|US5510685 *||Jul 22, 1994||Apr 23, 1996||Grasselli; Giorgio||Electric motor control based on conductive contact of machine component with operator for injury prevention|
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|US6003247 *||May 23, 1997||Dec 21, 1999||Steffe; Daniel D.||Anti-static boot having a conductive upper|
|US7979958 *||Nov 22, 2006||Jul 19, 2011||Andreas Stihl Ag & Co. Kg||Work apparatus|
|US9301558 *||May 10, 2012||Apr 5, 2016||Dan Schlager||Cardiopulmonary lightning protection garment|
|US20070136976 *||Nov 22, 2006||Jun 21, 2007||Andreas Stihl Ag & Co. Kg.||Work apparatus|
|US20130298319 *||May 10, 2012||Nov 14, 2013||Dan Schlager||Cardiopulmonary lightning protection garment|
|EP0079572A1 *||Nov 10, 1982||May 25, 1983||Emile Paul Jules Jean Ducros||Conductive shoe|
|International Classification||A43B7/14, A43B7/20, A43B7/36, A43B7/00|
|Cooperative Classification||A43B7/36, A43B7/20|
|European Classification||A43B7/20, A43B7/36|