CA1260818A - Tilting seat - Google Patents
Tilting seatInfo
- Publication number
- CA1260818A CA1260818A CA000509288A CA509288A CA1260818A CA 1260818 A CA1260818 A CA 1260818A CA 000509288 A CA000509288 A CA 000509288A CA 509288 A CA509288 A CA 509288A CA 1260818 A CA1260818 A CA 1260818A
- Authority
- CA
- Canada
- Prior art keywords
- seat
- stem
- buttocks support
- base
- vertical plane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Chairs Characterized By Structure (AREA)
- Chairs For Special Purposes, Such As Reclining Chairs (AREA)
Abstract
Abstract of the Disclosure A tilting seat having a base for supporting the seat on the floor and a stem extending upwardly from the base, either integrally or separably from the base, the seat being arranged such that it tilts about a tilting axis passing through the base such that a user can tilt the seat forward when in a working position. The base may be a turntable.
Description
~2608~l8 The present invention relates to seats, and particularly to a tilting seat.
It is estimated that between 65 and 75~ of days lost from work is due to back ailmen-ts. More and more, particularly wi-th the development of compu-ters, the worker is required to spend a greater amount of -time si-tting at a work station. On -the other hand, most conventional chairs or seating arrangements presently u-tilized in the workplace require the us~r to hunch forward in order to work at a desk or table. By hunching forward, the stress on the lumbar region ir, increased by 300~, resulting in premature disin-tegration of the lower discs and vertebral arthritic degeneration.
In recent years, a myriad of "ergonomically"
designed chairs have been developed, all of which use a backward inclined seat. Although these chairs have proved to be more "comfortable" in -the reclined position, the user is s-till obliged -to hunch forward in order to work at a desk or table. By hunching forward, the stress on the lower spine (lumbar region) is increased some 300~; the result being a premature disintegration of the lower discs and vertebral arthritic degeneration.
Recent research has brought about a greater com-prehension of the function of the lumbar spine and brings into question the basic traditional seated work position.
sased on the sound physiological evidence as provided by internationally recognized experts such as Doctors Keegan, Nachemson, and Grandjean, the ideal seated work posture should maintain a minimum curve in the lower spine ~lordosis). This position allows the efficient support of body weight, with the least amount of work and s-tress. In most cases, a person using a backward inclined seat, 3~ ' 1~0818 eradicates the lordosis by leaning forward to work. The forward inclined seat compensates for this necessary move-ment towards the work surface by allowiny the person to tilt his whole body forward, thus elimina-ting -the rounding of the back and the subsequen-t loss of the lordotic curve.
The forward incline makes it possible for a person -to maintain this critical lordosis of the lumbar spine while performing many different tasks.
Recent research has brought about a greater unders-tanding of -the s-truc-ture and function of the lumbar spine and brings into ~uestion the basic traditional seat-ing and the position of the user. According to physiologi-cal evidence, the ideal seated work pos-ture should maintain a minimum lordotic curve in the lower spine. This position allows the efficient support of the body weight with the least amoun-t of stress.
It is an aim of the present invention to provide a seat which would be comfortable in a res-t position, that is, in a normal sitting position, and which would tilt for-ward with the user as the user advances himself to the worktable, thereby generally maintaining an upright back posi-tion with a slight lordotic curve of -the lumbar region.
It is also an aim of the present invention to provide a seat which will be inclined forwardly when the seat is advanced or tilted towards a work position and allows the user to tilt his or her body forward, -thus eliminating the hunching of the back and the subsequent loss of lordosis in the lumbar spine.
A construction in accordance with the present invention comprises a seat having a base, a stem pivotally mounted on the base and tiltable relative to the base about a pivot axis at the base, a buttocks support mounted on the ~260~318 front of the stem, the stem extending rearwardly at an acute angle from a vertical plane containing the pivot axis and adapted to pivot from a rest position to a forward positlon where the s-tem is subs-tantially near rearward of the vertical plane, the cen-ter of -the bu-t-tocks support being substantially near the vertical plane in the rest position and forward of the vertical plane in -the forward position, and means on the base limiting the pivoting arc of travel of the stem between the rest posi-tion and the forward posi-tion.
In a more specific construction of the present invention, the buttocks support is mounted -to -the fron-t of the stem for llmi-ted pivotal movement relative to -the stem about an axis parallel to -the tilting axis.
It has been found tha-t in a preferred embodiment the stem in its rest posi-tion would be supported at an angle of 21 from the vertical plane and at an angle of 9 from the vertical plane in its forward position such that the total pivotal arc of travel of the s-tem is 12.
Thus, this construction allows the user to sit back on the seat or chair when not working over a work desk or table. However, when the user moves forward to work over the table, the buttocks support and the stem would merely follow the user and tilt forward allowing the user to maintain a proper erect position with the proper lordotic curve in the lumbar region. It is believed that this would allow the user to work in a much more comfort-able position with considerably less, stress on his back.
; The phenomenon is similar to the natural inclination, particularly with youngsters, to sit on the edge of their chair while working over a table. It has also been found, in studies, that it is important to maintain a relatively ..' , ~Z6~81~
open or obtuse angle between the -thighs and -the upper body.
With the embodiments described herein, thls ob-tuse angle can be main-tained between the thighs and the upper body even when the user is working over his work -table due to the tilting ancl inclination of the bu-t-tocks suppor-t on the seat. Using an ordinary chair, even if moving the chair forward under the table while working over the table, the thighs assume a closed or acute angle with respect to the upper body when the user is hunched over the table.
~laving thus generally descrlbed the na-ture of -the inven-tion, re~erence will now be made to the accompanying drawings, showing by way of illustration, a preferred embodiment thereof, and in which:
Figure 1 is a perspective view of one embodiment of the seat in accordance with the present invention;
Figure 2 is a side elevation of the seat shown in Figure l;
Figure 3 is a fron-t eleva-tion of a seat showing another embodiment of -the present inven-tion;
Figure 4 is a vertical cross-section taken along line 4-4 in Figure 3;
Figure 5 is a fragmentary enlarged cross-section taken along line 5-5 in Figure l;
Figure 6 is an enlarged fragmentary cross-section taken along line 6-6 of Figure 3;
Figure 7 is a fragmentary top plan view of a detail of the present invention;
Figure 8 is a schematic view showing the different positions of the seat;
3 260~
Figure 9 is a front elevation of the base in accordance with an embodimen-t of the present inven-tion;
Figure 10 is a side elevation of the base shown in Figure 9;
Figure 11 is a vertical cross-section taken through a detail similar to that shown in Figure S, of another differen-t embodiment thereof;
Figure 12 is a fragmentary enlarged cross-section of a detail similar -to tha-t shown in Figure 5 but of a different embodiment thereof;
Figure 13 is an enlarged fragmentary sectional view along line 13-13 of Figure 12;
Figure 14 is a bottom plan view of the base shown in Figure 9;
Figure 15 is a cross-sec-tional view taken along line 15-15 of Figure 14; and Figure 16 is a cross-sectional view, sim~lar to Figure 15, bu-t showing a detail thereof in a different operative posi-tion.
Referring now to the drawings, there is shown in Figures 1 and 2, a first embodiment of a seat 10 including a base 12, a stem 14, and a buttocks support 16.
The base 12 and stem 14 in this embodiment are integral, and as s:hown in Figure 2, the base 12 describes an acute angle with the stem 14 extending over -the base 12 at an angle of 71. The buttocks support 16 is made of rnolded plastics material and may have a shell 18 and a soft interior 20. The buttocks support 16 is pivotally mounted at 22 on a bracket 24 which can be adjustably located along ~Z60~1~
the longitudinal axis of -the stem 14.
The stem 14 is in the form of an elonga-ted member having a track 26 in the form of an elongated slo-t having a T-shaped cross-section. As shown in Figure 5, -the bracket 24 lncludes a carr:iage 28 sliding in the track 26. The carriage 28 i.s provided with a series of spaced-apart apertures 30 wi-th each aperture having a radial flange 32.
The back of the stem 14 is provided with a bore 34.
A locking pin 36, including a rounded knob 38 and an L-shaped pin 40, passes through the bore 34. The lock-ing pin 36 also includes a spring 42 in the recessed part of -the bore 34. The L-shaped pin 40 is adapted to engage in apertures 30 of the carriage 28 to lock the carriage in a selected position.
When it is required to release -the carriage 28 from a given position, the carriage must be moved upwardly slightly to disengage the L-shaped pin 40 from -the flange 32. The~ pin 40 is then retracted agains-t the spring 42 into the recessed portion 34, and -the carri.age 28 is then free to move t:o a new adjusted vertical position. The spring 42 will be effective to move the locking pin 40 to a new aperture 30 on the carriage 28 when such aperture is aligned therewith.
As also seen in Figure 5, the seat 16 is pivotally mounted on the pivot shaft 22 in the bracket 24, and the ; pivoting movement of the seat is restricted by a limit pin 44 which is fixed to the seat 16 and travels in an arcuate slot 46.
The stem 14 merges with the base 12 forming an acute angle with reference to the embodiment in Figures 1 and 2, and the angled surface 48 formed at the forward part : of the base 12 is rounded, allowing the seat t;o he pivoted .
~26a~
or tilted along the rounded surface 48 which defines a tilting axis of the seat 10.
As shown in Figures 1 and 2, the seat 10 is illus-trated in a res-t position. A user may sit on the seat in this position and be comfortably erec-t. If the user wishes to move forwardly to a work position within -the arc between the position shown in full lines and that shown in do-tted lines in Figure 2, he need merely move himself forward (i.e., over a table), and -the seat 10 will -tilt forward :L0 with him. In the case of -the embodimen-t shown in Figures 1 and 2, the seat will tilt about the axis defined by the surface 48, moving the center of gravity of -the user from a position over or behind the vertical plane containing the axis of tilting to a position shown in dot-ted lines in Figure 2 where the buttocks support 16 is well ahead of -the vertical plane so defined. The user's forward movemen-t also brings the center of gravity thereof beyond the verti-cal plane including the tilting axis, and the natural inclination to maintain an open obtuse angle f of the -thighs -to the upper body will cause the buttocks support 16 to pivot abou-t the shaft 22 through a possible angle d of 45. The angle f may vary from 130 in the rest position to 105 in the forward position. Thus, as seen in Figure 8, when the seat is tilted forwardly, the lordotic curve in the lumbar region of the spine is maintained.
The tilt:ing of the seat will normally be through an arc a in the drawings which may be in the area of 20, although -this arc may vary 5 either way.
It is also seen that if the user were to lean back from the table, the seat 10 will, because of its stable position, tilt back to a rest position as shown in Figures 1 and 2 in full lines.
:.: ' :~. . ;
.
Another embodiment of the seat is shown in Figures 3, 4 and 6, in which -the base 50 is in the form of a turntable, including a sub-base 51. The sub-base 51 may have a rubber or soft plas-tic molded coverlng 52 over -the edge of a skirt 54 extending from an annulus 56 which is in a horizontal plane. A lower bearing race 58 is mounted to the annulus 56 and supports ball bearings 60 as shown in Figure 6. An upper base portion 62 is provided which mounts an upper race 64 which cooperates with -the lower race 58 and the ball bearings 60. The upper base portion 62 has an overhanging skirt 66. The upper base por-tion 62 moun-ts a pair of ups-tanding journals 68 and 70 which receive an arcuate lower member 72 of the stem 74. The journals have a rearward stop 76 and a forward stop 78 which limit -the pivoting or tilting movement of the stem 74 relative to the base. The arc may be limited to 20. The arc, iden-tified by -the letter c, is actually 12 with the forward position at 9 from the vertical plane through the pivo-t axis and the rest posit::ion at 21 from the vertical plane.
In -t:he preferred embodiment, the stem 14 does not pass the vertical plane -through the pivot axis of the stem, but rather its movement terminates in a forward position slightly behind the vertical plane. As can be seen, however, the buttocks support 16 in the rest position has its center position in the vertical plane or just slightly behind the vertical plane, while in the forward position, the buttocks support 16 is in front of the vertical plane. The user of the seat as described supports its i.ull weigh-t on the seat both in the rest position and the forward position, as shown in Figure 8 of the drawings.
Thus, in the embodiment shown in Figures 3 ~nd 4, the user has the advantage of the tilting seat previously ~l2~ 8 described and may rota-te -the seat on the -turntable.
Figures 7 and 8 represen-t the eEfec-t on -the body and in particular as represen-ted by a skeleton diagram in these drawings. The bu-ttocks suppor-t 16 is provided wi-th an enlarged mound 80 forward and central of -the support which influences the thigh bones to ro-tate outwardly in the direction of the arrows shown in Figure 7, -to provide a more natural and comfortable seating. Figure 8 represents the position of the lumbar region of -the spine in both the rest position and the tilting position of -the seat 10.
A different embodiment of -the base is illus-trated in Figures 9, 10, and 14 through 16. The base 110 includes a turntable por-tion 112 and an upstanding pedestal 114. As shown in Figure 10, the pedestal 114 includes a slot defined by a pair of abutments 116 and 118 which limit the pivoting arc of travel of the stem 14. The s-tem 14 includes two ears 120 which are ~ournaled on a pivot shaft 122. The abutment surface 116 is provided with a bellows type resilient device 124 while the abutmen-t 118 is pro-vided with a resilient stop 126. The base, as best shownin Figures 14 through 16, includes a sub-frame 128 mounted by means of a rubber or plastic suspension device 130 to the shell 132. The shell 132 includes a skirt 134 surroun-ding the periphery of the sub-frame 128. The sub-frame 128 is provided with a series of openings 136. A leg 138 is integrally molded at 140 to the sub-frame 128 or may be otherwise fixed thereto. The other end of the leg 138 includes a head 1~2 defining a spherical socket mounting a ball 144. The legs 138 are chosen of a material and size such that when there is no weight on the seat, the balls 144 are in contact with the ground or floor, but as soon as a weight is applied to the seat, the legs 138 will flex to g ~(3!818 allow the sub-frame 128 to rest on the floor and thereby prevent the rolling movement of the base.
Referring now to Figures 12 and 13, there is shown a stem 14 having a carriage 150 sliding in -the track 152. The carriage 150, which is similar to carriage 28, mounts a bracket 154. A pivot shaft 156 is fixed to the bracket 15~, and a pair of downwardly extending ears 158 are pivotally mounted to -the shaft 156. The ears 158 mount the shell 160 of the buttocks support. A small resilien-t pad 162 :is provided on the upper surface of -the bracket 154 to act as a stop for the rearward pivoting movement of the buttocks support 16.
Figure 11 illus-tra-tes another embodiment of the locking pin 36. The embodimen-t in Figure 11 has reference numeral~; raised by 200 which correspond with the numerals in Figure 5. The carriage 228 in this embodiment is made in the i.orm of a U-shaped channel with apertures 230 pro-vided Oll one side thereof. The carriage 228 slides in -the track 226. The locking pin 236 includes an L-shaped pin 240 moving in a sleeve 241 against the spring 242. A pin 244 acts as a forward limit for the pin 240. The ball or knob 238 is retained on the pin 240 by means of a ball retainer nut 246 fixed to the pin 240. The sleeve 241 includes flanges 243 on the interior of the track 226, as illustrated. The operation of the locking pin 236 is the same as the locking pin 36.
It is estimated that between 65 and 75~ of days lost from work is due to back ailmen-ts. More and more, particularly wi-th the development of compu-ters, the worker is required to spend a greater amount of -time si-tting at a work station. On -the other hand, most conventional chairs or seating arrangements presently u-tilized in the workplace require the us~r to hunch forward in order to work at a desk or table. By hunching forward, the stress on the lumbar region ir, increased by 300~, resulting in premature disin-tegration of the lower discs and vertebral arthritic degeneration.
In recent years, a myriad of "ergonomically"
designed chairs have been developed, all of which use a backward inclined seat. Although these chairs have proved to be more "comfortable" in -the reclined position, the user is s-till obliged -to hunch forward in order to work at a desk or table. By hunching forward, the stress on the lower spine (lumbar region) is increased some 300~; the result being a premature disintegration of the lower discs and vertebral arthritic degeneration.
Recent research has brought about a greater com-prehension of the function of the lumbar spine and brings into question the basic traditional seated work position.
sased on the sound physiological evidence as provided by internationally recognized experts such as Doctors Keegan, Nachemson, and Grandjean, the ideal seated work posture should maintain a minimum curve in the lower spine ~lordosis). This position allows the efficient support of body weight, with the least amount of work and s-tress. In most cases, a person using a backward inclined seat, 3~ ' 1~0818 eradicates the lordosis by leaning forward to work. The forward inclined seat compensates for this necessary move-ment towards the work surface by allowiny the person to tilt his whole body forward, thus elimina-ting -the rounding of the back and the subsequen-t loss of the lordotic curve.
The forward incline makes it possible for a person -to maintain this critical lordosis of the lumbar spine while performing many different tasks.
Recent research has brought about a greater unders-tanding of -the s-truc-ture and function of the lumbar spine and brings into ~uestion the basic traditional seat-ing and the position of the user. According to physiologi-cal evidence, the ideal seated work pos-ture should maintain a minimum lordotic curve in the lower spine. This position allows the efficient support of the body weight with the least amoun-t of stress.
It is an aim of the present invention to provide a seat which would be comfortable in a res-t position, that is, in a normal sitting position, and which would tilt for-ward with the user as the user advances himself to the worktable, thereby generally maintaining an upright back posi-tion with a slight lordotic curve of -the lumbar region.
It is also an aim of the present invention to provide a seat which will be inclined forwardly when the seat is advanced or tilted towards a work position and allows the user to tilt his or her body forward, -thus eliminating the hunching of the back and the subsequent loss of lordosis in the lumbar spine.
A construction in accordance with the present invention comprises a seat having a base, a stem pivotally mounted on the base and tiltable relative to the base about a pivot axis at the base, a buttocks support mounted on the ~260~318 front of the stem, the stem extending rearwardly at an acute angle from a vertical plane containing the pivot axis and adapted to pivot from a rest position to a forward positlon where the s-tem is subs-tantially near rearward of the vertical plane, the cen-ter of -the bu-t-tocks support being substantially near the vertical plane in the rest position and forward of the vertical plane in -the forward position, and means on the base limiting the pivoting arc of travel of the stem between the rest posi-tion and the forward posi-tion.
In a more specific construction of the present invention, the buttocks support is mounted -to -the fron-t of the stem for llmi-ted pivotal movement relative to -the stem about an axis parallel to -the tilting axis.
It has been found tha-t in a preferred embodiment the stem in its rest posi-tion would be supported at an angle of 21 from the vertical plane and at an angle of 9 from the vertical plane in its forward position such that the total pivotal arc of travel of the s-tem is 12.
Thus, this construction allows the user to sit back on the seat or chair when not working over a work desk or table. However, when the user moves forward to work over the table, the buttocks support and the stem would merely follow the user and tilt forward allowing the user to maintain a proper erect position with the proper lordotic curve in the lumbar region. It is believed that this would allow the user to work in a much more comfort-able position with considerably less, stress on his back.
; The phenomenon is similar to the natural inclination, particularly with youngsters, to sit on the edge of their chair while working over a table. It has also been found, in studies, that it is important to maintain a relatively ..' , ~Z6~81~
open or obtuse angle between the -thighs and -the upper body.
With the embodiments described herein, thls ob-tuse angle can be main-tained between the thighs and the upper body even when the user is working over his work -table due to the tilting ancl inclination of the bu-t-tocks suppor-t on the seat. Using an ordinary chair, even if moving the chair forward under the table while working over the table, the thighs assume a closed or acute angle with respect to the upper body when the user is hunched over the table.
~laving thus generally descrlbed the na-ture of -the inven-tion, re~erence will now be made to the accompanying drawings, showing by way of illustration, a preferred embodiment thereof, and in which:
Figure 1 is a perspective view of one embodiment of the seat in accordance with the present invention;
Figure 2 is a side elevation of the seat shown in Figure l;
Figure 3 is a fron-t eleva-tion of a seat showing another embodiment of -the present inven-tion;
Figure 4 is a vertical cross-section taken along line 4-4 in Figure 3;
Figure 5 is a fragmentary enlarged cross-section taken along line 5-5 in Figure l;
Figure 6 is an enlarged fragmentary cross-section taken along line 6-6 of Figure 3;
Figure 7 is a fragmentary top plan view of a detail of the present invention;
Figure 8 is a schematic view showing the different positions of the seat;
3 260~
Figure 9 is a front elevation of the base in accordance with an embodimen-t of the present inven-tion;
Figure 10 is a side elevation of the base shown in Figure 9;
Figure 11 is a vertical cross-section taken through a detail similar to that shown in Figure S, of another differen-t embodiment thereof;
Figure 12 is a fragmentary enlarged cross-section of a detail similar -to tha-t shown in Figure 5 but of a different embodiment thereof;
Figure 13 is an enlarged fragmentary sectional view along line 13-13 of Figure 12;
Figure 14 is a bottom plan view of the base shown in Figure 9;
Figure 15 is a cross-sec-tional view taken along line 15-15 of Figure 14; and Figure 16 is a cross-sectional view, sim~lar to Figure 15, bu-t showing a detail thereof in a different operative posi-tion.
Referring now to the drawings, there is shown in Figures 1 and 2, a first embodiment of a seat 10 including a base 12, a stem 14, and a buttocks support 16.
The base 12 and stem 14 in this embodiment are integral, and as s:hown in Figure 2, the base 12 describes an acute angle with the stem 14 extending over -the base 12 at an angle of 71. The buttocks support 16 is made of rnolded plastics material and may have a shell 18 and a soft interior 20. The buttocks support 16 is pivotally mounted at 22 on a bracket 24 which can be adjustably located along ~Z60~1~
the longitudinal axis of -the stem 14.
The stem 14 is in the form of an elonga-ted member having a track 26 in the form of an elongated slo-t having a T-shaped cross-section. As shown in Figure 5, -the bracket 24 lncludes a carr:iage 28 sliding in the track 26. The carriage 28 i.s provided with a series of spaced-apart apertures 30 wi-th each aperture having a radial flange 32.
The back of the stem 14 is provided with a bore 34.
A locking pin 36, including a rounded knob 38 and an L-shaped pin 40, passes through the bore 34. The lock-ing pin 36 also includes a spring 42 in the recessed part of -the bore 34. The L-shaped pin 40 is adapted to engage in apertures 30 of the carriage 28 to lock the carriage in a selected position.
When it is required to release -the carriage 28 from a given position, the carriage must be moved upwardly slightly to disengage the L-shaped pin 40 from -the flange 32. The~ pin 40 is then retracted agains-t the spring 42 into the recessed portion 34, and -the carri.age 28 is then free to move t:o a new adjusted vertical position. The spring 42 will be effective to move the locking pin 40 to a new aperture 30 on the carriage 28 when such aperture is aligned therewith.
As also seen in Figure 5, the seat 16 is pivotally mounted on the pivot shaft 22 in the bracket 24, and the ; pivoting movement of the seat is restricted by a limit pin 44 which is fixed to the seat 16 and travels in an arcuate slot 46.
The stem 14 merges with the base 12 forming an acute angle with reference to the embodiment in Figures 1 and 2, and the angled surface 48 formed at the forward part : of the base 12 is rounded, allowing the seat t;o he pivoted .
~26a~
or tilted along the rounded surface 48 which defines a tilting axis of the seat 10.
As shown in Figures 1 and 2, the seat 10 is illus-trated in a res-t position. A user may sit on the seat in this position and be comfortably erec-t. If the user wishes to move forwardly to a work position within -the arc between the position shown in full lines and that shown in do-tted lines in Figure 2, he need merely move himself forward (i.e., over a table), and -the seat 10 will -tilt forward :L0 with him. In the case of -the embodimen-t shown in Figures 1 and 2, the seat will tilt about the axis defined by the surface 48, moving the center of gravity of -the user from a position over or behind the vertical plane containing the axis of tilting to a position shown in dot-ted lines in Figure 2 where the buttocks support 16 is well ahead of -the vertical plane so defined. The user's forward movemen-t also brings the center of gravity thereof beyond the verti-cal plane including the tilting axis, and the natural inclination to maintain an open obtuse angle f of the -thighs -to the upper body will cause the buttocks support 16 to pivot abou-t the shaft 22 through a possible angle d of 45. The angle f may vary from 130 in the rest position to 105 in the forward position. Thus, as seen in Figure 8, when the seat is tilted forwardly, the lordotic curve in the lumbar region of the spine is maintained.
The tilt:ing of the seat will normally be through an arc a in the drawings which may be in the area of 20, although -this arc may vary 5 either way.
It is also seen that if the user were to lean back from the table, the seat 10 will, because of its stable position, tilt back to a rest position as shown in Figures 1 and 2 in full lines.
:.: ' :~. . ;
.
Another embodiment of the seat is shown in Figures 3, 4 and 6, in which -the base 50 is in the form of a turntable, including a sub-base 51. The sub-base 51 may have a rubber or soft plas-tic molded coverlng 52 over -the edge of a skirt 54 extending from an annulus 56 which is in a horizontal plane. A lower bearing race 58 is mounted to the annulus 56 and supports ball bearings 60 as shown in Figure 6. An upper base portion 62 is provided which mounts an upper race 64 which cooperates with -the lower race 58 and the ball bearings 60. The upper base portion 62 has an overhanging skirt 66. The upper base por-tion 62 moun-ts a pair of ups-tanding journals 68 and 70 which receive an arcuate lower member 72 of the stem 74. The journals have a rearward stop 76 and a forward stop 78 which limit -the pivoting or tilting movement of the stem 74 relative to the base. The arc may be limited to 20. The arc, iden-tified by -the letter c, is actually 12 with the forward position at 9 from the vertical plane through the pivo-t axis and the rest posit::ion at 21 from the vertical plane.
In -t:he preferred embodiment, the stem 14 does not pass the vertical plane -through the pivot axis of the stem, but rather its movement terminates in a forward position slightly behind the vertical plane. As can be seen, however, the buttocks support 16 in the rest position has its center position in the vertical plane or just slightly behind the vertical plane, while in the forward position, the buttocks support 16 is in front of the vertical plane. The user of the seat as described supports its i.ull weigh-t on the seat both in the rest position and the forward position, as shown in Figure 8 of the drawings.
Thus, in the embodiment shown in Figures 3 ~nd 4, the user has the advantage of the tilting seat previously ~l2~ 8 described and may rota-te -the seat on the -turntable.
Figures 7 and 8 represen-t the eEfec-t on -the body and in particular as represen-ted by a skeleton diagram in these drawings. The bu-ttocks suppor-t 16 is provided wi-th an enlarged mound 80 forward and central of -the support which influences the thigh bones to ro-tate outwardly in the direction of the arrows shown in Figure 7, -to provide a more natural and comfortable seating. Figure 8 represents the position of the lumbar region of -the spine in both the rest position and the tilting position of -the seat 10.
A different embodiment of -the base is illus-trated in Figures 9, 10, and 14 through 16. The base 110 includes a turntable por-tion 112 and an upstanding pedestal 114. As shown in Figure 10, the pedestal 114 includes a slot defined by a pair of abutments 116 and 118 which limit the pivoting arc of travel of the stem 14. The s-tem 14 includes two ears 120 which are ~ournaled on a pivot shaft 122. The abutment surface 116 is provided with a bellows type resilient device 124 while the abutmen-t 118 is pro-vided with a resilient stop 126. The base, as best shownin Figures 14 through 16, includes a sub-frame 128 mounted by means of a rubber or plastic suspension device 130 to the shell 132. The shell 132 includes a skirt 134 surroun-ding the periphery of the sub-frame 128. The sub-frame 128 is provided with a series of openings 136. A leg 138 is integrally molded at 140 to the sub-frame 128 or may be otherwise fixed thereto. The other end of the leg 138 includes a head 1~2 defining a spherical socket mounting a ball 144. The legs 138 are chosen of a material and size such that when there is no weight on the seat, the balls 144 are in contact with the ground or floor, but as soon as a weight is applied to the seat, the legs 138 will flex to g ~(3!818 allow the sub-frame 128 to rest on the floor and thereby prevent the rolling movement of the base.
Referring now to Figures 12 and 13, there is shown a stem 14 having a carriage 150 sliding in -the track 152. The carriage 150, which is similar to carriage 28, mounts a bracket 154. A pivot shaft 156 is fixed to the bracket 15~, and a pair of downwardly extending ears 158 are pivotally mounted to -the shaft 156. The ears 158 mount the shell 160 of the buttocks support. A small resilien-t pad 162 :is provided on the upper surface of -the bracket 154 to act as a stop for the rearward pivoting movement of the buttocks support 16.
Figure 11 illus-tra-tes another embodiment of the locking pin 36. The embodimen-t in Figure 11 has reference numeral~; raised by 200 which correspond with the numerals in Figure 5. The carriage 228 in this embodiment is made in the i.orm of a U-shaped channel with apertures 230 pro-vided Oll one side thereof. The carriage 228 slides in -the track 226. The locking pin 236 includes an L-shaped pin 240 moving in a sleeve 241 against the spring 242. A pin 244 acts as a forward limit for the pin 240. The ball or knob 238 is retained on the pin 240 by means of a ball retainer nut 246 fixed to the pin 240. The sleeve 241 includes flanges 243 on the interior of the track 226, as illustrated. The operation of the locking pin 236 is the same as the locking pin 36.
Claims (9)
1. A seat having a base, a stem having upper and lower ends, the lower end of the stem being pivotally mounted on the base and tiltable relative to the base only about a transverse pivot axis at the base, a buttocks support mounted in a cantilever manner on the front of the stem such that the upper end of the stem projects above the buttocks support, the stem extending rearwardly over the base and adapted to pivot in an arc of movement, means for limiting the pivot arc of movement in a vertical plane normal to the transverse axis between a rest position with the stem at an acute angle behind a vertical plane taken through the transverse pivot axis with a center of said buttocks support being substantially near the vertical plane through the transverse pivot axis and a forward position when the stem is adjacent but behind the vertical plane through the transverse pivot axis and the center of the buttocks support is forward of the vertical plane.
2. A seat as defined in claim 1, wherein the buttocks support is pivotally mounted on a bracket mounted to the stem, and means are provided for limiting the pivoting movement of the buttocks support about an axis parallel to the transerse pivot axis of the stem in an arc limited between a first and second position.
3. A seat as defined in claim 2, wherein the buttocks support is adjustable in height relative to the stem by means of a track provided on the stem, and sliding track follower means provided on the bracket of the buttocks support, and locking means being provided for locking the track follower at a selected height of the buttocks support on the stem.
4. A seat as defined in claim 1, wherein the arc of movement of the stem between the rest position and the forward position is within 20°.
5. A seat as defined in claim 4, wherein the arc of movement of the stem is between 21° and 9° from the vertical plane.
6. A seat as defined in claim 2, wherein the buttocks support has a limited pivoting arc within the range of 45°.
7. A seat as defined in claim 1, wherein said base includes a first member having a peripheral floor engaging edge, cantilevered resilient members mounting floor engagement wheels, the resilient cantilevered members being such that when there is no load on the buttocks support of the seat, the wheels are in contact with the floor and the floor engaging edge is spaced from the floor allowing the seat to be moved on said wheels, and when a load is borne by the buttocks support, the additional weight overcomes the resilient cantilevered members such that the peripheral edge of the base is in contact with the floor to thereby arrest the seat in a given position.
8. The structure as claimed in claim 7, wherein the wheels are in the form of roller balls mounted in a socket at the end of the cantilevered members.
9. The structure as claimed in claim 7, wherein the base includes a sub-frame which is circular and the peripheral edge thereof has a circular locus; the resilient cantilevered members extending radially from an inner portion of the sub-frame and extending outwardly towards the edge, said cantilevered members being regularly spaced so that the seat is completely supported by the wheels when the buttocks support is free of any additional load such that the seat can be moved on the floor, freely in any direction.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US853,673 | 1986-04-18 | ||
| US06/853,673 US4738487A (en) | 1984-05-22 | 1986-04-18 | Tilting seat |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1260818A true CA1260818A (en) | 1989-09-26 |
Family
ID=25316622
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000509288A Expired CA1260818A (en) | 1986-04-18 | 1986-05-15 | Tilting seat |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS62246317A (en) |
| AU (1) | AU595304B2 (en) |
| CA (1) | CA1260818A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AUPM463394A0 (en) * | 1994-03-22 | 1994-04-14 | Nash, Adrian | A support for a seat |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NO118082B (en) * | 1963-03-25 | 1969-11-03 | Wilhelm Ackermann | |
| US3679260A (en) * | 1970-05-21 | 1972-07-25 | Bath Inst Of Medical Eng The | Invalid chairs |
| US3625563A (en) * | 1970-05-22 | 1971-12-07 | Us Army | Tank commander{40 s seat and foot platform assembly |
-
1986
- 1986-05-15 CA CA000509288A patent/CA1260818A/en not_active Expired
- 1986-08-21 JP JP19414786A patent/JPS62246317A/en active Pending
-
1987
- 1987-04-16 AU AU71755/87A patent/AU595304B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| AU595304B2 (en) | 1990-03-29 |
| AU7175587A (en) | 1987-10-22 |
| JPS62246317A (en) | 1987-10-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |