Classifications

• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47C—CHAIRS; SOFAS; BEDS
  • A47C3/00—Chairs characterised by structural features; Chairs or stools with rotatable or vertically-adjustable seats
  • A47C3/02—Rocking chairs
  • A47C3/021—Rocking chairs having elastic frames
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47C—CHAIRS; SOFAS; BEDS
  • A47C7/00—Parts, details, or accessories of chairs or stools
  • A47C7/02—Seat parts
  • A47C7/14—Seat parts of adjustable shape; elastically mounted ; adaptable to a user contour or ergonomic seating positions
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47C—CHAIRS; SOFAS; BEDS
  • A47C7/00—Parts, details, or accessories of chairs or stools
  • A47C7/36—Support for the head or the back
  • A47C7/40—Support for the head or the back for the back
  • A47C7/46—Support for the head or the back for the back with special, e.g. adjustable, lumbar region support profile; "Ackerblom" profile chairs

Definitions

• the present invention is related to the field of furniture design and it concerns the furniture with improved construction as regards aspect of anthropometries, enabling the anatomical adjustment in the sitting position. More specifically, the invention is related to a general purpose chair with a cantilever type seat fixed on the front side of the seat, which enables the anatomical adjustment of low back support for users of various body heights and various weights, as well as in various sitting positions.
• This invention solves the problem of automatically adjusting chairs with anatomical chair back shape, having a concentrated pressure on the low back of a sitting person. Since a comfortable and anatomically correct sitting requires that a concentrated pressure of the persons back on the chair back should be in the point of the low back (lumbal zone), it is necessary to find a way to adjust this position for users of various body heights, i.e. various low back heights, as well as to find a way of adjusting when changing the sitting position forward - backward (by moving the lower part of the body back and forward on the seat).
• the most important function of the chair back is to provide support to the lumbal zone of the backbone. This concave low part of the backbone stretches approximately from the waist till the middle of the backbone. From that reason the chair back has to be co-ordinated with the backbone profile in the lumbal zone, which enables support of the lumbal zone by the chair back.
• the first one is how to provide the correct leaning of lumbal zone for a greater number of users 1 of various body • heights, having also various heights of lumbal zone 2 in relation to the seat surface level, according to the figure 1.
• the second problem is that the sitting itself, being a dynamical activity, involves temporary a spontaneous changing of sittmg position by moving back and forward on the seat. Simultaneously with body moving, the point of backbone support in relation to the chair back is also changed.
• the figure no. 2 shows the chair type with the fixed chair back. If, by an upright sitting position of user 1, the position of the lumbal zone 2 corresponds to the most convex point on the chair back, i.e. to lumbal support 3 (since they are at the same height as shown in the figure 2), it means that the condition of a comfortable, i.e. anatomical correct support by sitting is fulfilled.
• the existing chairs can be divided into the following groups :
• This function of self-adjustment is based upon assumption that a great number of users have height and weight, that can be approximated by a linear dependence (the taller the user- the larger the weight.). Since the cantilever deformation depends upon the applied force, a taller and havier user will cause larger deformation, which with most users enables direct leaning of the lumbal zone on the lumbal support.
• Solution of the problem of chair self adjustment for user's moving forward- backwards on the seat is based on the fact that cantilever deformation decreases by shortening of effective cantilever length (with the same vertical pressure on the seat).
• the effective length of cantilever (and it's deformation) decreases, and the height of lumbal support in relation to the seat level also decreases, so that the position of the lumbal zone center comes very close to lumbal support center, when moving back or forward to any sitting position.
• the chair offers a comfortable, i.e. anatomically correct support for most users and most sitting positions.
• Fig. 1 Various heights of lumbal zone in relation to the seat surface level, depending upon user's body height (technical problem)
• Fig. 2 A chair with the fixed chair back (background art)
• Fig. 3 A chair with the flexible chair back (background art)
• Fig. 4 Schematic longitudinal section of the chair through the seat and the chair back with various cantilever loads.
• Fig. 5 Schematic longitudinal section of the chair for users of various body heights
• Fig. 6 Schematic longitudinal section of the chair through the seat and the chair back with a different cantilever load point
• Fig. 7 Schematic longitudinal section of the chair showing the user in various sitting positions
• Fig. 8 A chair with ulti layer cantilever
• Fig. 9 A chair with multiple cantilever
• Fig. 10 A real solution - a chair with flexible chair back
• Fig. 11 A real solution - a chair with flexible chair back
• Fig. 4 shows the schematic longitudinal section of the chair through the seat and the chair back. It can be seen that the seat - cantilever 20 has the fixed point 21 on the front side of the chair. At the same time the free part of the seat - cantilever can take various positions 22 and 23, which depends upon various loads shown as vertical vector force 24 and 25.
• the height 28 is suitable for person 26, and height 29 is suitable for person 27 (Fig. 4 and 5).
• cantilever stiffness reference force - deformation
• FIG. 6 and 7 show that the load point represents the vertical projection of the lowest pelvic bone part on the seat.
• the load point is moved from position 31 into position 32. Since by such moving the effective cantilever length decreases from the length 33 to the length 34, so will cantilever deformation be smaller in the front position 32.
• Fig. 6 shows an ideal case when user moves forward on the seat and the lumbal zone 2 does not move in relation to the lumbal support 3, what means that distance of load points 31 and 32 its the same in relation to the support point 3.
• positions 31 and 32 are extreme positions (upright and the most distant position)
• This ideal case is not real because of seat flexibility (point 3 moves) and because of backbone bending by changing of the sitting position.
• the center of the lumbal zone 2 will be very close to lumbal support 3 for all forward-backwards moving positions.
• relation force-deformation on the free end will be chosen according to the weight and lumbal zone height range with most users.
• the proper cantilever deformation (while moving forward) might be adjusted by proper choice of cantilever length - by moving the cantilever fixed point back towards free end. It means that by choice of various users' heights and various sitting positions we can use two free parameters, the cantilever length and stiffness.
• Relation deformation-moving (forward- backwards) can also be adjusted by changing specific stiffness along the cantilever. This adjustment is possible in many ways, for example the multy layer cantilever as shown in fig. 8 or multiply cantilever as shown in fig.9. The essence of invention will not be changed by using such or similar solutions.

Landscapes

• Orthopedics, Nursing, And Contraception (AREA)
• Chair Legs, Seat Parts, And Backrests (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=25548197

Family Applications (1)

Country Status (5)

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• 2002
  • 2002-01-29 CA CA002435752A patent/CA2435752A1/en not_active Abandoned
  • 2002-01-29 US US10/470,964 patent/US20040070248A1/en not_active Abandoned
  • 2002-01-29 RU RU2003123090/12A patent/RU2003123090A/ru not_active Application Discontinuation
  • 2002-01-29 WO PCT/YU2002/000001 patent/WO2002060299A1/en not_active Application Discontinuation
  • 2002-01-29 EP EP02710651A patent/EP1357822A1/en not_active Withdrawn

Non-Patent Citations (1)

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