US1567695A - Backrest - Google Patents

Description

R. C. ANGELL Dec. Z9

BACKREST Filed Sept. 21 1923 4 Sheets-Sheet 1 i i abe/"f CT Hag/ell,

R. C. ANGELL Dec. 29 1925' BACKREST Filed Sept. 21 1923 4 Sheets-Sheet 2 Clttowoq Dec. 29 1925. 1,567,695

R. c. ANGELL BACKREST Filed Sept. 21 1923 4 Sheets-Sheet 5 Dec. 29 1925- 1,567,695

R. c. ANGELI.

BACKREST Filed Sept. 21 1923 4 Sheets-Sheet 4 FIC?. .9.

Ffa ja GWW Patented Dec. 29, 1925.

UNITED STATES PATENT OFFICE.

ROBERT c. ANGELI., or rRnron Bannay# YORK. AssIGNoR 'ro THR s. s. WHITE DENTAL MANUFACTURING COMPANY,

A QORPORATION F PENNSYLVNIA.

Vnacmnsr.

Application led September 21, 1923. Serial No. 663,967.

Be it known that l, ROBERT C. ANGEIL, a citizen ot' the United States, and a resident of lrince Bay, in the county of Richmond, State of New York, have invented certain new and useful Improvements in Backrests, of which the following is a specification, reference being had to the accompanying drawings. A

lvly invention relates particularly to thatl type of back-rests that are designed for em bodiinent in dental chairs and is vespecially directed tothe conformation of its anterior or supporting surface against which the back of an occupant of the chair may rest.

lhc principal objects of my invention are to provide a backrest formed of variably curved transverse zones so related as to afford a concaved anterior surface arranged to closely conform to the back of the human forni and affording outwardly extending lateral projections tending to closely embrace the' waist of said form and arranged to afford a feeling of security and consequent comfort and confidence to the occupant of the chair. Y'

Other objects of my invention are to provide a back-rest which may bel formed of sheet material shaped to form a shell arranged to coliform to the back and closely hug the waist of a human form and having its perimetral margin drawn backwardly to provide a continuous reinforcing flange which may be cooperatively associated with a back plate or shell of sheet material.

My invention comprehends a back-rest that will not only afford maximum comfort, but that is economical to manufacture, light in weight, readily covered with leather, fabric, paint, enamel, or other superficial covering; that will radiate the heat of the body occupying the chair, thereby producing a sensation of coolness in hot weather; and that is highly sanitary.

My invention further includes novel means for joining the forward and rearward shells of the back-rest together and for hingedly connecting said back-rest to its support.

The form of my invention, -as hereinafter described, comprises a back-rest formed of complementary shells of stamped sheet metal respectively having rim flanges relatively overlapped and joined to form a hollow body whose anterior wall is shaped to conform to the back of a human form, and having its upper and lower zones concaved transversely andits medial zone relatively concaved to conform to the waist of said form, and affording forwardly extending lateral protuberances tending to closely tembrace said waist.

My invention also includes all of the various novel features of construction and arrangement as hereinafter more definitely specified. In the accompanying drawings Figure 1 1s a plan view of a back-rest conveniently embodying my invention; Fig. 2 is a rear elevational view of the back-rest shown in Fig. 1; Fig. 3 is a plan View of the forward shell of said back-rest per se; Fig. 4 is a fr ont elevational view of said forward shell; Fig. 5 1s a central vertical longitudinal sectional view of the forward shell of said backrest, taken on the axial plane of symmetry 5 5; Fig. 6 1s a central vertical longitudinal sectional view of the assembled backrest, taken on the line 6 6 in Fig. 2; Fig. 7 1s a transverse horizontal sectional view of said back-rest, taken on the line 7 7 in Figs. 2 and 6; Fig. 8 is a transverse sectional view talien in a plane at one-tenth of the length of said back-rest, spaced from the top on the line 8 8 in Figs. 4 and 5; Fig. 9 is a transverse sectional view taken in a plane at twotenths of the lengthof said back-rest, on the line 9 9 in Figs. 4 and 5; Fig. 10 is a transversesectional view taken in a plane at threetenths of the length of said back-rest, on the line 10 10 in Figs. 4 and 5; Fig. 11 is a transverse sectional view taken in a plane at four-tenths of the length of said hack-rest, on the line 11-11 in Figs. 4 and 5; Fig. 12 is a transverse sectional view taken in a plane at five-tenths of the length of. said back-rest, on the line 12 12 in Figs 4 and 5; Fig. 13 is a transverse sectional view taken in a plane at six-tenths of the length of said back-rest, on the line 13 13 in Figs. 4 and 5;

' Fig. 14 is a transverse sectional view taken in a plane at seven-tenths of lthe length of said back-rest, on the line 14'-14 in Figs. 4 and 5; Fig. 15 is a transverse sectional view taken in a plane at eight-tenths of the4 length of said back-rest, on the line 15-15 in' Figs. 4 and 5; and Fig. 16 is a transverse sectional view taken in a plane at nine-tenths of the length of said back-rest, spaced'from the top, on the line 16 16 in Figs. 4 and '5.

In said figures the back-rest comprisesv the forward shell 1 and rearward shell 2, each preferably formed of sheet metal and having rim flanges 3 and 4 relatively telescope'd with their margins preferably overlapping to form a hollow body.

Said rearward'shell 2 curves to generally conform to the forward shell 1 and has its medial region flattened to afford an inset plane wall 5, to which the forward shell 1 may be rigidly secured by the transversely extended strap brackets 6 which as best shown in Fig. 7, have their ends secured to said forward shell by rivets 9 and their rearwardly extended straight intermediate portions 11 removably engaged with said plane wall 5 of the rearward shell 2 by the screws 12. n'

The rearward shell 2 is also p rovided with reinforcing plates 14 and 15 disposed within the shell, to which the back-rest frame 16 may be conveniently attached by the screws 17 and 18 extended through said shell 2, in threaded engagement with the respective plates 14 and 15.. I

The back-rest frame 16 is provided with recesses 19 affording bearings for the trunnions 20 of the rock-shaft 21 upon which the back-rest may be oscillated to adjust its inclination, and said trunnions are maintained in said bearings by the retaining plate 22, having the apertures 23 and 24 through 'which the bosses 26 and 27, which afford convenient attachment to a chair back slide of well known construction, may extend.

The back-rest covering which I have chosen to illustrate, comprises a sheet of fabric or leather 30 overlying the metallic shell 1 with an interposed lining of felt 32, or other suitable resilient material, and having its perimetral margin 33 preferably engaged between the opposed telescoped rim flanges 3 and 4 of the shells 1 and 2, respectively.

rlhe forward shell 1 is shaped to conform to the back of the human form, being concaved transversely and increasing m its curvature from its top and bottom toward its medial transverse zone to conforinto the waist of said human form, and'to provide forwardly projecting lateral protuberances 36 and 37 of substantial extent, exceeding one-seventh of the width of said shell, and tending to closely embrace said waist to afford lateral support for the occupant of the chair.

Said forward shell 1 concavedly curves laterally in opposite directions from the axial plane of symmetry 5 5, and forwardly from a plane 50 50 tangent to the transverse curve of said back-rest at the axis of Symmetry and normal to said plane of symmetry.

In order that the contour of the forward shell 1 of the back-rest may be better understood, it has been divided transversely into ten equal parts by horizontal planes 8 8 to 16 16 inclusive, each disposed normal to both the plane of symmetry 5 5 and the transverse tangential plane 50-50, in the order of their numerical notation from the top downward.

As best shown in Figs. 8 to 16 inclusive, representing the transverse sections which divide the shell 1 into ten equal parts, the outer margin of said shell is sharply curved backwardly into the rim flange 3, which thereby affords perimetral convexed ridge crests 34 and 35 variably spaced both from the plane of symmetry 5 5, and from the transverse tangential plane 50-50, and projecting substantially from the latter to its maximum extent between the transverse planes of Sections 13 13 and 14--14 to form the lateral protuberances 36 and 37 to which reference is made.

The crests 34 and 35 of the ridges at the opposite sides of the back-rest are represented by the dash lines on Fig. 4 and are spaced as follows in the plane of section 8 8, at one-tenth of the length of said back-rest from the top, said ridge crests are spaced approximately nine and three-quarter inches apart, or sixty-eight-hundredths of the length of said back-rest, and approximately one-half inch or three-and-one-half-hundredths of said length from the tangential plane 50 50;`in the plane of section 9 9, at two-tenths of the length of said back-rest, said crests are spaced approximately twelvevand-oneu rter inches apart or eighty-sixhundredt of the length of the back-rest,

and approximately seven-eights of an inch or six-hundredths of said length from the tangential plane 50 50; in the plane of section 10-10, at three-tenths of the length of said back-rest from the top, said crests are spaced approximately thirteen-and-one-half inches apart or ninety-five-hundrdths of the length of said back-rest, and approximately one-and-one-eighth inches or eighthundredths of said length from the tangential plane 50-50; in the plane of section 11 11, at four-tenths of the length of said back-rest from the top, said crests are spaced approximately fourteen and. one eighth inches apart or ninety-nine-hundredths of the length of said back-rest, and approximately one-and-f'ive-eighths inches or elevenand-one-lialf-hundredths of said length from the tangential plane 50 50; in the plane of section 12-12, at five-tenths of the length of said back-rest from the top, said crests are spaced approximately fourteen-and-one-quarter inches apart or one hundred hundredths of the length of said back-rest, and approximately two inches or fourteen hundredths of said length from the tangential plane 50 50; in the plane of section 13 13, at six-tenths of the length of said back-rest from the top, said crests are beck-rest from the top,

spaced approximately fourteen-and-one-half -inches apart or.ninety-eight-hundredths of the length of said back-rest, and .approximately two-and-one-quarter inches or iifteen-and-one-half-hundredths of said length from the tangential plane 50'--50; 1n the plane of section 11k-14, at seven-tenths of the length of said back-rest from the top, said crests are spaced approximately thirteen-and-one-quarter inches apart or ninety-three-hundredths of the` length of said .back-rest, and approximately two-andone-quarter inches or hundredths of said length from the tangential plane 50-'-50; in the plane of section 15-15, at eight-tenths of the length of said said crests are spaced approximately twelve-and-.one-half inches apart or eighty'-eight-hundredths of the length of said back-rest, and approximately one-and-three-quarters inches or twelve-andone-half-hundredths of said length from the tangential plane 50-50; and in theplane of section 16-16, at nine-tenths of the length of said back-rest from the top, said crests are spaced approximately elevenand-oneeighth inches apart or seventy-elght-hundredths of the length of 'said back-rest, and approximately one inch or seven-hundredths of said length from the tangential plane 50-50.

My invention is advantageous in that the proportions herein set forth provide a backrest that will afford equal comfort tothe back of a wide range of persons of varying size and weight, including alike children as well as adults.

Although I have described the flanges of the respective shells as being telescoped it may be advanta eous in some instances, par- I ticularly when t e shells are to be enameled,

to so abut the edges of the flanges as to be welded or otherwise secured and therefore, l do not desire to limit my invention to the precise details of construction and ar rangement as herein specified, as it is obvious that various modifications may be made therein without departing from the essential features of my invention as defined in the appended claims.

Having thus described 'my invention, l claim I 1. A back-rest for a dental chair having its longitudinal axis of symmetry dispose in a plane, and its anterior surface variably curved outwardly therefrom and extended laterally forward to form curved protuberances projecting forwardly from said plane approximately one-seventh of the width of said back-rest and arranged to closely embrace the/waist of a human form.

2. A back-rest for a dental chair havin its longitudinal axis of symmetry disposed in a plane, and its anterior surfaces variably curved outwardly therefrom and exfteen-and-one-'halfj tended laterally forward to form curved protuberances projecting forwardly from said plane to an extent exceeding oneseventh of the maximum Width of said backrest and arranged to closely embrace the waist of a human form.

3. A back-rest for a dental chair having its anterior surface curved outwardly from a plane tangent to its longitudinal axis of symmetry, and adually increasing in its curvature towar its medial transverse zone to form lateral forwardly extending protuberances projecting from said plane to an extent approximately one-seventh of the maximum width of said back-rest, and arranged to closely embrace the waist of a human form.

4. A. back-rest for a dental chair having its anterior surface curved outwardly from a plane tangent to its longitudinal axis of symmetry, and'gradually increasing in its curvature from the top and bottom of said back-rest toward its medial transverse zone, and affording lateral forwardly extending protuberances projecting from said plane to thelr maximum extent at approximately between six-tenths and seven-tenths of the length of said back-rest .from the top.

5. iv back-rest for a dental chair having its anterior` surface concaved outwardly from a plane tangent thereto at its lon itudinal axis of symmetry, and gradual y lncreasing in curvature from the top and bottom of said back-rest toward its medial transverse zone, and alording lateral forwardly extending protuberances projecting from said plane to an extent approximately ifteen-andone-halfhundredths of the length of said back-rest.

6. A back-rest for a dental chair having its anterior surface concaved, curving outwardly from a plane tangent thereto at its longitudinal axis of symmetry and graduall v varying in curvature and turned to form a perimetral convex ridge projecting from said plane approximately three-and-onehalf-hundredths of the length vof said backrest at one-tenth of said length from its top; approximately six-hundredths at twotenths; approximately eight-hundredths at three-tenths; approximately eleven-and one-half-hundredths at four-tenths; approximately fourteen-hundredths at tived tenths; approximately fifteen-andone-half hundredths at six-tenths; approximately ifteen-and-one-half-hundredths at seventenths; approximately twelve-and-one-halfhundredths at eight-tenths; and approximately seven-hundredths of the length of said back-rest at nine-tenths of said length from its to 7 A baci-rest for a dental chair having its anterior surface concaved, curving laterally outward from a plane tangent to its longitudinal axis of symmetry and normal to its axial plane of symmetry, and gradually varying in curvature to form a perimetral convex ridge whose crest varies 1n relation to both said axial plane of symmetry and said tangential plane, being disposed aproximately thirty-four-hundredths of the Fength of said back-rest from said plane of symmetry and three-and-one-half hundredths of said length from sald tangential plane, in a transverse plane cutting sald back-rest at one-tenth of its length from its top; forty-three-hundredths from said plane of symmetry and six-hundredths from said tangential plane, in a transverse plane at two-tenths from the top; forty-seven-andone-half-hundredths from said plane of symmetry and eight-hundredths from said tangential plane, in a transverse plane, at three-tenths from the top; forty-nine-andone-half-hundredths from said plane of symmetry and eleven-and-one-half-hundredths from said tangential plane, in a transverse plane, at four-tenths from the top; fifty-hundredths from said plane of symmetry and fourteen-hundredths from said tangential plane, in av plane at fivetenths from the top; forty-nine-hundreths from the plane of symmetry and fifteen-ando-ne-half-hundredths from said tangential plane, in a plane at six-tenths from the top;

' fortysix-and-one-halfhundredths f r om said plane of symmetry and fifteen-and-onehalf-hundredths from said tangential plane, in a plane at seven-tenths from the top; forty-four-hundredths from the plane of symmetry and twelve-and-one-half-hundredths from said tangential plane, in a plane at eight-tenths from the top, and thirty-nine-hundredths from the plane of symmetry and seven-hundredths from said tangential plane, in a plane at nine-tenths of the length of said back-rest from its top.

8. A back-rest for a dental chair having its anterior surface concaved, curving laterally outward from a plane tangent to its longitudinal axis of symmetry, and gradually varying in curvature throughout its extent and affording forwardly directed marginal crests variably spaced both laterally and with respect to said tangential plane as follows :-in a transverse plane at one-tenth of the length of said back-rest, the oppositely disposed crests are spaced approximately nine-and-three-quarters inches apart and approximately one-half inch from the tangentlal plane; in a transverse plane at two-tenths of its length, the opposite crests are spaced twelve-and-one-quarter inches apart, and seven-eighths of an inch from said tangential plane; in a transverse plane at three-tenths of its length, the opposite crests are spaced thirteen-and-onehalf-inches apart, and one-and-oneeighth the opposite crests are spaced 'fourteen inches apart, and twoand-one-quarter inches from said tangential plane; in a transverse plane seven-tenths of its length, thc opposite crests are spaced thirteen-andone-quarte'r inches apart, and two-and-onequarter inches from said tangential plane; in a transverse plane eight-tenths of its length, the opposite crests are spaced twelveand-one-half inches apart, and one-andthree-quarters inches from said tangential plane; and in a transverse plane at ninetenths of its length, the opposite crests are spaced eleven-and-one-eighth inches apart., and one inch from said tangential plane.

9. A back rest formed of sheet material and comprising a forward shell having variably curved transverse zones affording ,laterally disposed, forwardly projecting areas arranged to embrace and closely conform to the waist of a human form, and havirg its edge margins drawn backwardly to a ord a reinforcing flange, a rearward shell closely conformin in a spaced relation to said forward s ell, and having a medial inset plane wall facilitating attachment of said forward shell therewith, and having a forwardly drawn flange cooperative with the flange on said forward shell to form a hollow body; and a strap bracket having its ends Secured to said forward shell and its intermediate portion extended rearwardly and connected with the plane inset wall of said rearward shell.

l0. A back-rest formed of sheet material and comprising a forward shell having its upper and lower zones concaved transversely, and its intermediate zone relatively curved to conform to the waist of the human form, and affording forwardly extending lateral protuloerances tending to closely embrace said waist, a rearward shell closely conforming to said forward shell in spaced relation thereto, and having a medial inset plane wallufacilitating attachment to said forward shell, and means interposed between said forward and rearward shells arranged to attach them together.

In witness whereof, I have hereunto set my hand this 31st day of August, A.. D., 1923.

ROBERT e. ANGELL.

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