# US 5,332,324 A · Ergonomic instruments > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,332,324 A - Document ID: US5332324A - Status: Granted - Kind: A - Application number: 08/016,463 - Filed: 1993-02-11 - Granted: 1994-07-26 - Earliest claimed: 1991-05-31 - Inventors: Michael A. Hochstetler - Web page: https://patentgrep.com/patent/US5332324A ## CPC - B43K 23/004: Holders specially adapted for assisting handicapped or disabled persons to write (B43L15/00 takes precedence) - B43K 7/005: {Pen barrels} - B43K: IMPLEMENTS FOR WRITING OR DRAWING (containers, casings or accessories for cosmetic substances, e.g. shaving soap, lipstick, make-up A45D34/00, A45D40/00) ## Abstract An ergonomic, hand held instrument comprising an instrument and a shell. The shell has a longitudinal axis and opposite ends and a hollow interior. The instrument is positioned within the shell with its operational end extending from one end of the shell. The shell has a groove therein extending from adjacent the one end at least a partial revolution about said shell to adjacent the other end. The groove has a bottom and an upstanding wall. The groove spirals around the shell. The bottom has a width greater than the size of one's fingers. The spiral may have one or more partial turns or a single continuous turn or partial turn between the opposite ends of the shell. The bottom extends from the wall toward the other end and is tapered from one turn of the wall to an adjacent turn of the wall with the wall facing the other end whereby one can pick up the instrument and very easily grip the instrument correctly with a lighter grip than with conventional instruments and yet press harder during use without the fatigue, cramps or calluses normally related to use of the instrument for long periods of time. ## Claims ### Claim 1 An ergonomic, hand held instrument comprising a shell having a longitudinal axis having opposite ends and a hollow interior, an instrument positioned within said interior of said shell with its operational end extending from one of said shell ends, said shell having a groove therein extending from adjacent said one shell end axially of said shell, said groove having a bottom surface and an upstanding wall adapted for the fingers and the thumb of the hand holding the instrument to be positioned in said groove against said upstanding wall to apply a force in the axial direction during use, said groove spiraling around said shell, said bottom surface having a width greater than the size of the pad of said fingers, said groove having at least one partial turn adjacent to said one end and between said opposite shell ends, said bottom surface extending from said wall axially toward said other shell end, said fingers having no walls therebetween when placed in said groove, whereby one can pick up said instrument and easily grip said instrument correctly with a lighter grip than with conventional instruments and yet use without hand fatigue, cramps or calluses normally associated with use of the instrument for long periods of time. ### Claim 2 (depends on 1) The instrument of claim 1 wherein said shell is tapered from said one end to said other end, said one shell end being smaller in diameter than said other end. ### Claim 3 (depends on 1) The instrument of claim 1 wherein said wall and bottom are smoothly joined. ### Claim 4 (depends on 1) The instrument of claim 1 wherein the height of said wall is from about 0.0625 to about 0.1875 inches. ### Claim 5 (depends on 1) The instrument of claim 1 wherein said wall is sloped with respect to said axis. ### Claim 6 (depends on 5) The instrument of claim 5 wherein said wall and said axis define an angle of about 30.degree. about 55.degree.. ### Claim 7 (depends on 6) The instrument of claim 6 wherein said angle is about 45.degree.. ### Claim 8 (depends on 1) The instrument of claim 1 wherein said shell is at least about 5 inches in axial length, said turns are about 4 in number, said one shell end is from about 0.1875 to about 0.3325 inches in diameter and said other shell end is from about 0.63 to about 0.37 inches in diameter. ### Claim 9 (depends on 2) The instrument of claim 2 wherein said shell adjacent said shell ends in conical. ### Claim 10 (depends on 9) The instrument of claim 9 wherein the joints of said wall and bottom are smoothly rounded, the height of said wall is from about 0.625 to about 0.1875 inches, said wall is sloped with respect to said axis, said wall and axis define an angle of about 30.degree. to about 55.degree., said shell is at least about 5 inches long, said turns are about 4 in number, said one shell end is from about 0.1875 to about 0.3325 inches in diameter, and said other shell end is from about 0.67 to about 0.37 inches in diameter. ### Claim 11 (depends on 10) The instrument of claim 10 wherein said bottom is about 1 inch wide. ### Claim 12 (depends on 1) The instrument of claim 1 wherein said bottom is about 1 inch wide. ### Claim 13 (depends on 1) The instrument of claim 1 wherein said bottom surface is sloped with respect to said axis. ### Claim 14 (depends on 1) The instrument of claim 1 wherein said shell is tapered from said one shell end to said other shell end, said one shell end being smaller in diameter than said other shell end, said wall and bottom being smoothly joined. ### Claim 15 (depends on 1) The instrument of claim 1 wherein said shell is tapered from said one shell end to said other shell end, said one shell end being smaller in diameter than said other shell end, said wall and bottom being smoothly joined, said wall and bottom surface being sloped with respect to said axis. ### Claim 16 (depends on 1) The instrument of claim 1 wherein said shell is tapered from said one shell end to said other shell end, said one shell end being smaller in diameter than said other shell end, said wall and bottom being smoothly joined, said wall and bottom being sloped with respect to said axis, said shell ends being conical. v