Patent application title: Novel design for ergonomic hand grip that can be used for writing instruments
James Wukjae Lee (San Diego, CA, US)
IPC8 Class: AA46B1700FI
Class name: Coating implements with material supply with means to attach or conform to body of user
Publication date: 2009-10-01
Patent application number: 20090245916
This invention is an improvement in hand held devices used for marking,
pointing, or touching. The improvement is comprised of a novel grip for
the purpose of comfort. The grip incorporates novel materials and novel
shape to accomplish said purpose. This invention is also comprised of a
barrel that is able to accept a mechanism for intended use, marking,
pointing, or touching, while also being able to be attached to the said
grip in a manner that is able to accomplish said purpose
1. A device with a grip for a purpose comprising: a cylindrical shape
having a plurality of radial and longitudinal indentations or
2. The device of claim 1, wherein said purpose is for comfort.
3. The device of claim 1, wherein said Indentations or protrusions have a difference in their height as measured from axial center.
4 The device of claim 3, wherein said indentations and protrusions cover an area in size that is adequate to interact with all parts of the hand that are involved in grasping said grip.
5. The device of claim 4, wherein the size of said indentations and protrusions is optimized to interact with the bones of the hands and fingers through interference, similar to the action that teeth of opposing gears undergo.
6. The device of claim 4, wherein the size of said indentations or protrusions is optimized to allow the continued flow of blood in tissues and the relief of pressure on nerves.
7. The device of claim 5, wherein the size of indentations and protrusions relative to the distance from axial center is 0.001 to 0.3 inches.
8. The device of claim 6, wherein the size of indentations and protrusions relative to the distance from axial center is 0.001 to 0.3 inches.
9. The device of claim 1, wherein said grip is comprised of a material.
10. The device of claim 9, wherein material has sufficiently low durometer to provide relief of high pressure points on tissues of the hand whole holding said grip.
11. The device of claim 9, wherein said material has a high coefficient of friction to aid in the reduction of tension needed by the hand to grasp said grip.
12. The device of claim 10 & 11, where in said material may consist of substances known as thermoplastic elastomers.
13. The device of claim 12 wherein said material may consist of a single thermoplastic elastomer or a combination of different thermoplastic elastomers to attain the best characteristics for said purpose of claim 2.
14. The device of claim 13, wherein said material may be a combination of thermoplastic elastomers CL40 and CL2003 as manufactured by GLS corporation.
15. The device of claim 14, wherein said material may be a mix of 60% CL40 and 40% CL2003 as manufactured by GLS Corporation.
16. The device of claim 1, wherein said material may be colored for aesthetic purposes.
17. The device of claim 1 should be of a shape and size that it will both fit within the grip without affecting comfort and large enough to hold the any mechanisms necessary for its function.
This application claims priority to provisional patent, application
number U.S. 61/072,126, filing date Mar. 28, 2008.
CROSS-REFERENCE TO RELATED APPLICATIONS
STATEMENT REGARD FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT
REFERENCE TO A "SEQUENCE LISTING," A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISC AND AN INCORPORATION-By-REFERENCE OF THE MATERIAL ON THE COMPACT DISC
BACKGROUND OF THE INVENTION
There have been attempts in the past to create a more comfortable grip for writing instruments. What is described in this text pertains to all instruments interacting with the hand. But for simplicity, I will mention only the pen. One surface is the pen grip and the other is the surface are the parts of the hands and fingers that come into contact with the grip.
These past efforts have been in the pursuit of the obvious to attain comfort. That is, they tried to incorporate changes that sounded like they would be comfortable. Soft, smooth, and sleek are all adjectives that can be used to describe the instruments made with these characteristics in mind. Previous attempts have realized marginal success at best.
Herein is described a design for a pen grip that addresses the real ergonomic needs of a writer's hand and fingers, the addressing of which results in a truly comfortable pen.
First, one must assess why writing can result in pain. It can be summed up with the following concept: excess grip pressure resulting in hand muscle ischemia, high tendon tension, and neuropraxia.
The Cartesian XYZ axes will be used for orientation in that the plane of writing surface (paper for example) would be the XY plane and that the writing instrument would point toward that plane along the Z axis.
To attain pen tip pressure along the Z axis that produces a mark (especially to produce marks on triplicate, or carbon copy papers), hand pressure in that along that same axis must be transmitted to the pen tip. The fingers must exert grip pressure on the sides of pen grip that ensures adequate friction, to prevent pen from slipping. Pen tip pressure, which is necessary to make a mark, is mainly along the axis of the writing instrument, is essentially parallel to hand pressure and perpendicular to grip pressure.
If the pen is designed poorly, high grip pressures are needed to attain the proper level of friction. In other words, you have to hold the pen tightly to make a mark. With excess grip pressure comes other associated problems all leading to pain. These problems include ischemia, tendonitis, and neuropraxia.
Writing with such a poorly designed instrument puts stress on the many muscles of the hand. These muscles include, but are not limited to, the interosseous, thenar, and flexor digitorum muscles. With great tension in these muscles comes decrease in blood flow into these muscles as blood has to flow against this rise in pressure in these muscle groups.
If tension in contracting muscles (the result of holding a pen really hard) causes pressure within this tissue that is greater than blood pressure, then indeed no blood will flow into the muscle at all. Blood carries oxygen in. If the muscles use more oxygen than can be delivered, cramping occurs. This of course is quite painful. Most are familiar with term "Charlie horse." This is cramping of the leg muscles.
Tendonitis can occur if high tension on the tendons injures the tendons themselves. Repeated injury causes repetitive stress injury and associated inflammation with results in pain.
Also, with increasing grip pressure, there is a concomitant increase in finger tip pressure. The finger tips have one of the highest densities of nerve endings in the body. Pressure on nerves themselves prevents flow of nutrient along the nerve resulting in a condition called neuropraxia which causes anything from temporary numbness to permanent pain syndromes (you experience temporary symptoms of this as the "pins and needles" your foot "falls asleep").
Most pens in existence rely almost entirely on friction to convert this writing pressure to pen tip pressure along the Z axis.
Poor designs utilize smooth, slick surface on the pen grip. The coefficient of friction is for this set up is low and would thus require great pen grip pressure.
Slightly better designs have increased the coefficient of friction by utilizing slightly rubberized surfaces. Usually employing a silicon based plastic. But there is still large room for improvement.
Some, pens incorporate shape in an attempt to give a more comfortable writing experience. But, this shape had not been optimized.
BRIEF SUMMARY OF THE INVENTION
The perfect pen grip would increase the coupling of a deformable surface with the deformable surface of hand and finger tissues. One acceptable design would have a highly contoured surface in both radial and longitudinal aspects. An example would resemble a pattern of raised squares wrapped around the surface of the pen. This grip should be made with a material with a high coefficient of friction.
DESCRIPTION OF THE DRAWING
FIG. 1 shows a Grip on a pen with an appropriately sized gripping area. This grip would be large enough to allow all functional parts of the hand to be in contact with the grip. The radial indentations provide the proper interaction by interference with the hand. They do so by closely following the shape of the bones of the hand. The longitudinal indentations as indicated allow continued blood flow through the tissues of the hand. The longitudinal indentations also allow for the continued nutrient flow through the nerves.
DETAILED DESCRIPTION OF THE INVENTION
The design of a perfect pen grip must incorporate materials that allow for greater friction and to optimize interference (as described below) to transfer hand pressure to pen tip pressure. New materials have been created that have a higher coefficient of friction. These materials have not yet been used for pen grips. Also, the proper shape has not yet been incorporated.
Essentially, this problem is an issue of transferring a force parallel to the line of action. The hand force in the Z axis directed toward the XY plane must be transferred via grip pressure which is perpendicular to the Z axis. In order to create a better pen grip, we need to transfer hand pressure in the Z axis to pen tip pressure in the Z axis, which by definition are parallel. Gears utilize "interference" to efficiently transfer forces parallel to line of travel (when viewed at the point of contact between two gears)
Gears are essentially highly contoured pieces that mate with each other in terms of their contouring. Common gears are symmetrical and regularly shaped because of their use in rotary motion, but the principle of interference can occur with any highly contoured shape.
A highly contoured surface in a pen grip would allow for this interference to occur. By incorporating radial contours into the instrument grip, the tissues of the hand would have to deform less as the underlying bones would take on the force. The proper shape can be determined by utilizing xray photography. In doing so, the two surfaces would be forced to interfere along the line of force. One possible grip shape incorporating this would resemble a square wave or a sinewave when viewed from the side. These can be described as radial grooves or indentations.
In the course of writing and gripping the pen, forces in the X an Y axes also occur. These forces are needed to move pen tip to create markings on the paper. It would therefore be beneficial to have longitudinal grooves of the same nature to ensure interference for optimal transference of these motions as well. These indentations would also allow for greater longitudinal oxygen and nutrient flow.
One possible pattern would incorporate "criss-cross" grooves over the surface of pen grip that would result is a checker-board like pattern of raised squares along the surface of the pen grip. A grip of this design would allow minimal grip pressures that are necessary to perform writing tasks. This would result in minimizing any possible pain as a result.
With a reduction in necessary grip pressure, a number of other pain syndromes can be addressed, in particular arthritis, tendonitis, and carpal tunnel syndrome.
Arthritis is the painful inflammation of joints. In arthritis the more grip pressure required to write, the greater the stress on the joints that are painful. If you decrease required-grip-pressure you can decrease the pain experienced by the user.
Tendonitis and carpal tunnel syndrome are similar. Tendonitis is the inflammation of tendons. Carpal tunnel syndrome is the painful inflammation of the tendons and or their retaining structures that lie at the base of the hand. These are the very tendons responsible for moving the fingers and positioning the hand for writing. The less force needed to hold a pen and write, the less tension on these tendons, therefore the less pain experienced while writing.
Also, It should be noted that with the proper shaping and spacing of grooves that another benefit with regards to neuropraxia would be gained.
Along with allowing decreased grip pressure, the grooves would allow a decrease in impeded blood to flow in the areas of the finger not in direct contact with the higher areas of grip. That is, in the areas that are recessed in the pen and therefore putting lesser or no pressure on finger tissues, there will be
Also, as we write, we subconsciously make tiny alterations in the way we hold the pen. This is similar to the "tossing and turning" we do in our sleep. If we did not, we would get areas of pain as the tissues that we are resting on become ischemic. If we didn't ever change position tissues will eventually become necrotic or die.
Presented with a poorly designed grip this alteration is met with a grip that is identical. A smooth round surface would look and feel the same regardless of where a hand held it. We therefore would not benefit with this grip alteration. Contrasting this would be altering the way we hold a pen with a highly contoured surface. With high and low areas, a shift in grip will allow new areas to be in contact or not in contact with the pen grip. This would allow new areas to receive fresh blood, and therefore oxygen, with every shift of grip. All areas would eventually be regularly oxygenated--no cramping, no pain.
Ideally the grip of writing instruments should employs any of the following features:
The writing instrument employs a generally elongated and cylindrical shape that many people are already familiar and comfortable with. This elongated and cylindrical shape is optimized to accept a grip with the following description. The grip that is sized to include the entire area that is to be contacted by any part of the hand holding the instrument. The grip is shaped to allow areas of the hand most directly supported by the bones of the hand to have contoured contact points. Contact points may be radial indentations at those points contacted by the hand. One radial indentation to be included is contacted by the skin overlying any combination of areas that are described as involving the proximal phalanx of the index finger, head of the first metacarpal, thenar muscles (muscles that move the thumb), and the proximal phalanx of the thumb. Another radial indentation to be included is contacted by the skin overlying any combination of the areas that are described as involving the base of the distal phalanx of the index finger, base of the distal phalanx of the middle finger, base of the distal phalanx of the thumb. Another radial indentation to be included is contacted by any combination of the areas that are described as involving the tip of the distal phalanx of the index finger, tip of the distal phalanx of the middle finger, tip of the distal phalanx of the thumb. These indentations don't necessarily have to be utilized in the above fashion to be effective.
Texture is such to allow alternate pressure on blood vessels and nerves. The grip has raised areas and depressed areas such that slight rotation of grip around the longitudinal axis allows these areas to move relative to the hand and therefore offers varying pressure points to the areas of the hand that are contacting the pen. The resulting alternation of pressure allows different blood vessels to be open and supply nutrients and oxygen to tissues. This also allows nerves to replenish their nutrients which they do along their longitudinal axis.
Material employed by grip offers the maximum coefficient of friction. This material can be of a low durometer thermoplastic elastomer. High coefficient of friction ensures that low hand pressures are needed to supply normal force to apply longitudinal force (which is orthogonal to grip pressure) needed to write.
Also, material has the appropriate elasticity to provide feedback to the fingers of the user. This feedback allows the user to know how hard to hold the grip. Most grips are made of hard substances that have no "give." That is to say that the regardless of the pressure you put on the grip, the surface shape remains the same. The above mentioned material will deform at the appropriate pressure to give feedback to the fingers that correct grip pressure has been attained.
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