TOUCH ENHANCING PAD

Abstract: The invention relates to an apparatus which enhances the sense of touch when placed between the fingertips of the user and the object being touched and which comprises a liquid lubricant inside a sealed enclosure. The enclosure is formed of a pliable, elastic material having a wall thickness of about 0.003 to 0.020 inches. The liquid lubricant is present in an amount sufficient to fully coat the interior of the enclosure, but which also permits the enclosure to be flattened with at least about 75 percent of the surface area of one side in contact with the other side.

Description: FIELD OF THE INVENTION This invention relates to an apparatus which enhances the sense of touch. BACKGROUND OF THE INVENTION The sense of touch is one of the five senses by which we gather information about the world around us. The sense of touch gives rise to feelings of pleasure and pain and is used to determine the shape, hardness, texture, and temperature of objects. The sense of touch is used extensively in the field of medicine because the shape and hardness of body internals is often an excellent guide in diagnosing and treating disease. One of the most publicized uses of the sense of touch in medical diagnosis is the detection of breast cancer. One out of every eleven women in the United States develops breast cancer. It is the most common form of cancer in women and is the chief cause of cancer deaths among United States women. Early detection of breast cancer is considered extremely important in treating the disease. Breast cancer is characterized by the formation of lumps in the breast. These lumps can be detected by x-ray radiation photography or by manual examination. The known tendency of x-ray radiation to cause various types of cancer generally prevents its routine use for detection. Accordingly, most breast cancers are discovered by the detection of lumps by physical examination of the breasts. Manual examination of the breasts is included by most physicians in their routine examinations of adult women. To help with early detection, the American Cancer Society also recommends monthly selfexaminations for women. To reduce friction and thereby facilitate movement of the hands across the breasts, the American Cancer Society recommends that the monthly self-examinations be conducted during a bath or shower when the skin is wet and soapy. For any number of reasons, many women find it inconvenient to take the additional time for self-examination during their bath or shower. And, for obvious reasons, it is not practical to use water and/or soap as a skin lubricant for breast examination when partially clothed, e.g., at a physician's office. Creams, powders, or lotions are more suitable as friction reducers, but still are rarely used because of the mess. Therefore, most physicians and women conduct breast examinations by using their hands directly on dry skin. Unfortunately, manual examination of the breasts does not ensure that a lump will be detected. In an article entitled "Physicians' Abilities to Detect Lumps in Silicone Breast Models" published in the April 19, 1985 issue of the Journal of The American Cancer Society , (Vol. 253, No. 15, pp. 2224-2228) Dr. Suzanne W. Fletcher et al. of the University of North Carolina at Chanel Hill described a study which tested the ability of 80 physicians to detect lumps of varyins sizes, hardness, and depth in silicone breast models. Dr. Fletcher et al. found that the physicians were able to detect only 44 percent of the lumps. It is not difficult to understand why the detection results were so poor in the study. When conducting a breast cancer examination with bare hands on dry skin, the examiner must ignore the unwanted touch stimuli (i.e., the "noise", e.g., temperature, texture, and if a self-examination, stimuli from the breast itself) in favor of the desired touch stimuli which enable the determination of shape and hardness of an object (i.e., the "signal"). The sense of touch is clearly an ability which can be developed with practice. For example, thousands of blind persons are able to "read" braille lettering, but a sighted person touching braille for the first time is usually unable to distinguish the number of pattern of the protrusions. Consequently, Dr. Fletcher et al. recommended more training for physicians to better develop their senses of touch. Paschal, United States Patent 2,694,196, issued November 16, 1954, discloses and claims a massaging pad formed by sewing together a pair of satin sheets in such a way that friction between the sheets is reduced (the "warp" of one sheet is disposed at a substantial angle to the "warp" of the other). Paschal also discloses a modified from of the device comprising two sheets of flexible plastic material fused or sealed together with a lubricant on the inside. The Paschal device is allegedly an aid to massagers because it reduces the friction between the massager's hands and the body part being massaged. The device does not, however,enhance the sense of touch. Instead, the device masks the sense of touch because it is made of materials which do not readily transmit touch stimuli. SUMMARY OF THE INVENTION The general object of this invention is to provide an apparatus which enhances the sense of touch. A more particular object is to provide an apparatus which improves the ability to detect breast cancer by physical examination. We have discovered an apparatus which enhances the sense of touch when placed between the fingertips of the user and the object being touched. The apparatus comprises: (a) a sealed enclosure of a pliable, elastic material having a wall thickness of 0.076 to 0.51 mm (0.003 to 0.020 inches), a modulus at 300 percent of less than 10.34 × 10⁶Pa (1,500 lbs/sq. in. ("psi")), a tensile strength of greater than 20.68 × 10⁶Pa (3,000 psi), and an ultimate elongation of greater than 400 percent; and (b) a liquid lubricant inside the enclosure which has sufficient lubricity to reduce the coefficient of kinetic friction between the interior walls of the enclosure by at least 60 percent, a sufficiently-high resistance to mass transfer through the enclosure so that the amount of lubricant inside the enclosure remains substantially constant over time, the lubricant has substantial inertness towards the enclosure, and which present in an amount sufficient to fully coat the interior of the enclosure, provided that the amount of the liquid lubricant permit the enclosure to be flattened with at least 75 percent of the surface area of one side in contact with the other side. The use of this apparatus enhances the sense of touch and thereby improves the ability of its user to detect breast cancer by physical examination. The apparatus is also useful in other applications where the sense of touch is employed for diagnosis. The apparatus is non-toxic, reuseable, and leaves no residue on the hands of the user or on the object being touched. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a top view of the apparatus. Figure 2 is a cross-sectional view of the apparatus. DETAILED DESCRIPTION OF THE INVENTION This invention is best understood by reference to the drawings. Figure 1 is a top view of the touch enhancing pad showing an enclosure 10 which has an opening 11 closed off with a physical seal 12. Figure 2 is a cross-sectional view of the pad showing a quantity of a liquid lubricant 13 and a gas 14 inside the pad. To use the pad, it is first placed onto the object to be touched. The fingertips are then used to examine the object just as if the pad were riot present. The bottom wall of the pad (the one in contact with the object being touched) generally remains stationary while the top wall (the one in contact with the fingertips) moves with the fingertips. For what is believed to be a number of reasons, the touch stimuli used to determine shape and hardness are enhanced when the pad is used in this fashion. The enclosure is made of a material which readily transmits the desired touch stimuli through two of its layers and yet is strong enough to resist tearing or puncturing. The ability of a material to transmit touch stimuli is believed to be primarily a function of its thickness and its ability to conform to the contours of the object being touched. This ability to conform is, in turn, primarily a function of the material's pliability and elasticity. In summary, the properties desired for the enclosure material are strength, pliability, and elasticity. The material has a tensile strength of greater than 20.68 × 10⁶Pa (3,000 psi) and most preferably greater than 27.58 × 10⁶Pa (4,000 psi). The material has a thickness of 0.076 to 0.51 mm (0.003 to 0.020 inches). At this thickness, and with a tensile strenght of greater than 20.68 × 10⁶Pa (3,000 psi), the material is strong enough to resist tearing or puncturing and yet thin enough to readily transmit touch stimuli. The material preferably has a thickness of 0.25 mm to 0.38 mm (0.010 to 0.015 inches). The pliability of a material can be measured in terms of its modulus. Modulus is the force required to stretch a material a given amount. For use in this invention, a material has a modulus at 300 percent of less than 10.34 × 10⁶Pa (1,500 psi) and most preferably less than 4.83 × 10⁶Pa (700 psi). The material preferably has sufficient elasticity so that it can be stretched to at least four times its length without breaking. In other words, it is preferred that the material have an ultmate elongation of greater than 400 percent. It is most preferred that the ultimate elongation exceed 600 percent. Although a plurality of pieces of material can be joined together to form the enclosure, it is preferred that the enclosure be formed of a single piece of material because the presence of a seam of any type tends to interfere with the movement of the pad during use. The enclosure may be of any desired shape or size. For breast examination, a round enclosure having a diameter of 28.86 cm (9 inches) is preferred because it fully covers the breast. A highly preferred enclosure has the general shape of a round toy balloon with the single opening physically sealed to prevent the flow of liquid or gas therethrough. Suitable physical seals are clamps, bands, and the like. The interior walls of the enclosure are preferably as smooth as possible to facilitate low-friction movement of one side against the other. Materials exhibiting the above-described properties of strength, pliability, and elasticity are generally members of the class of polymers known as rubbers. A rubber enclosure of the preferred shape and wall thickness is conveniently manufactured by a process known as "dipping". In this process, a suitably-shaped metal or ceramic paddle is dipped into an emulsion of rubber polymer in water known as latex. The latex generally contains a vulcanizing ingredient, such as sulfur, and may also contain a coagulant to improve the deposition of rubber upon the paddle. After the desired period of dipping (ranging from seconds to several minutes), the paddle is withdraw and dried. The dry, vulcanized rubber product is then removed from the paddle. This method of manufacture is widely used for producing surgeons gloves, toy balloons, etc. Both synthetic and natural rubber latexes are suitable for use in making the enclosure. Synthetic rubber latexes are made of many different polymers, including polychloroprene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, etc. Natural rubber latex is obtained from the tree Hevea Braziliensis and is cleaned, preserved, and concentrated before use. The natural rubber latex is preferred because dipped rubber products from it generally exhibit superior properties of strength, pliability, and plasticity. The liquid lubricant reduces the friction between the interior walls of the enclosure and thereby eases movement of the top wall across the stationary bottom wall. The lubricant has sufficient lubricity to reduce the coefficient of kinetic friction between the interior walls by at least about 60 percent. The lubricant also has a sufficiently-high resistance to mass transfer through the walls of the enclosure so that the amount of lubricant inside the enclosure remains substantially constant over time. A mixture of water and soap is inexpensive, non-toxic, and has sufficient lubricity, but water tends to permeate through thin rubber walls, especially at elevated temperatures. The lubricant further has substantial inertness towards the enclosure so that it does not cause failure of the enclosure. Petroleum fractions and animal and vegetable oils are generally unsatisfactory due to their effect on rubber, especially natural rubber latex. The liquid lubricant is present in an amount large enough to fully coat the interior of the enclosure and yet small enough so that the user of the pad can examine an object with only a minimum layer of lubricant between the walls of the enclosure. The amount of the liquid lubricant preferably permits the enclosure to be flattened with at least about 75 percent of the surface area of one side in contact with the other side. As an example, about 10 to 30 ml of lubricant are preferred for use with a 22.86 cm (9 inch) diameter pad. While not critical to the invention, it is, of course, preferred that the lubricant be non-toxic. Preferred liquid lubricants include dimethylsilicone, glycerine, propylene glycol, and polyoxyethylene (also known as polyethylene glycol). The dimethylsilicone fluids are the most preferred lubricants, an example of which is Organosilicone Fluid L-45, a polydimethylsiloxane sold by the Union Carbide Corporation. The ease with which the pad is used is improved some-what if a volume of gas is also present inside the enclosure. The gas has substantial inertness towards the enclosure and is preferably air because of ease of manufacture. The volume of the gas is generally at least about double the volume of the liquid lubricant. The combined volumes of the liquid lubricant and the gas permit the enclosure to be flattened with at least 75 percent of the surface area of one side in contact with the other side. In the example of the 22.86 cm (9 inch) diameter pad, about 100 to 500 ml of gas are preferred. While not wishing to be bound by theory, it is believed that at least five factors contribute to the touch enhancing properties of the pad of this invention. First of all, the pad eliminates or masks certain touch stimuli such as temperature and texture and thereby improves the ability to detect the touch stimuli which enable the determination of shape and hardness. Secondly, the pad reduces friction between the user and the object being touched. This eases the movement of the fingertips across:he object and helps prevent any tendency of the fingertips to skip across a portion of the object. Thirdly, the pad helps immobilize the object being touched. A very small object, protrusion, or indentation is detected most readily by passing the fingertips across it. If the object moves with the fingertips, it is more difficult to detect. For example, it is very difficult to feel a single human heir upon a hard, smooth surface. At least part of the difficulty is because the hair tends to stick to the fingers. When the pad is used, the hair is immobilized and the fingertips can be moved back and forth across the hair, enabling it to be detected. Fourthly, the pad adheres to and follows the contours of objects so well that it, in effect, increases the size of the object for detection purposes. In the above example of the human hair, the increase in the hair's diameter by several thousandths of an inch (which results when one wall of the enclosure adheres to the hair) creates a much larger protrusion for the fingertips to feel. Fifthly, the pad may actually increase the surface area of the fingertips in contact with an object.

Claims: 1. An apparatus which enhances the sense of touch when placed between the fingertips of the user and the object being touched, characterised in that the apparatus comprises a sealed enclosure of a pliable, elastic material having a wall thickness of 0.076 to 0.51 mm (0.003 to 0.020 inches), a modulus at 300 percent of less than 10.34 × 10⁶Pa (1,500 psi), a tensile strength of greater than 20.68 × 10⁶Pa (3,000 psi), and an ultimate elongation of greater than 400 percent; and a liquid lubricant inside the said enclosure which has sufficient lubricity to reduce the co-efficient of kinetic friction between the interior walls of the enclosure by at least 60 percent, a sufficiently-high resistance to mass transfer through the enclosure so that the amount of lubricant inside the enclosure remains substantially constant over time, and the lubricant has substantial inertness towards the enclosure, the lubricant being present in an amount which is sufficient to fully coat the interior of the enclosure but which permits the enclosure to be flattened with at least 75 percent of the surface area of one side in contact with the other side 2. An apparatus as claimed in claim 1 characterised in that the enclosure comprises rubber prepared from natural or synthetic rubber latex. 3. An apparatus as claimed in claim 2 characterised in that it additionally comprises a gas inside the enclosure which is substantially inert towards the enclosure and which is present in a volume at least about double the volume of the liquid lubricant, the combined volumes of the liquid lubricant and the gas permitting the enclosure to be flattened with at least about 75 percent of the surface area of one side in contact with the other side. 4. An apparatus as claimed in claim 3 characterised in that the gas comprises air. 5. An apparatus as claimed in any of claims 1 to 4 characterised in that the enclosure is formed of a single piece of rubber which has a single opening physically sealed to prevent the flow of liquid or gas therethrough. 6. An apparatus as claimed in any of claims 1 to 5 characterised in that the enclosure comprises rubber prepared from natural rubber latex. 7. An apparatus as claimed in any of claims 1 to 6 characterised in that the enclosure material has a modulus at 300 percent of les than 4.83 × 10⁶Pa (700 psi), a tensile strength of greater than 27.58 × 10⁶Pa (4,000 psi), and an ultimate elongation of greater than 600 percent. 8. An apparatus as claimed in any of claims 1 to 7 characterised in that the lubricant comprises dimethylsilicone, glycerine, polyetbylene glycol, or propylene glycol. 9. An apparatus as claimed in any of claims 1 to 7 characterised in that the lubricant comprises dimethylsilicone. 10. An apparatus as claimed in any of claims 1 to 9 characterised in that the enclosure has a wall thickness of 0.25 mm and 0.38 mm (0.010 and 0.015 inches).

Inventors: PERRY, DONALD A., WRIGHT, H. EARL
Applicants: INVENTIVE PRODUCTS, INC.
Application year: 1986
Main classification: A61B10
IPC codes: A61B10, G09B23, A61B19