Chairs and seats – Bottom or back with means to alter contour – Providing support for lower back region
Patent
1997-01-15
1998-08-25
Nelson, Jr., Milton
Chairs and seats
Bottom or back with means to alter contour
Providing support for lower back region
2972842, 2972848, A47C 746
Patent
active
057976520
DESCRIPTION:
BRIEF SUMMARY
This invention relates to adjustable lumbar supports for seats and chairs, and is particularly although not exclusively concerned with such supports as used in association with motor vehicle seats. It will be convenient to hereinafter describe the invention with particular reference to motor vehicle seats, but it is to be understood that the invention has wider application. By way of example, the invention may be adopted in aircraft seats, train seats, shipboard seats, and chairs as used for office or recreational purposes.
Adjustable lumbar supports tend to be complex and of relatively expensive construction. The actuator through which adjustment is effected presents a particular problem because of its bulk and consequent limitations on where it can be located within the seat assembly. Some actuators are of such bulk that they need to be located remote from the lumbar support, and that necessitates the provision of complex and expensive means for drivably connecting the actuator to the lumbar support.
It is an object of the present invention to provide a relatively simple and inexpensive lumbar support assembly. It is a further object of the invention to provide such an assembly which can be quickly and conveniently attached to or removed from a seat. Still another object of the invention is to provide an improved lumbar support adjustment actuator which is of relatively compact construction and which requires relatively low effort to operate.
A lumbar support adjuster according to the present invention is characterised in that the drive mechanism which is operative to cause the adjustment of the lumbar support, extends and contracts between two conditions which correspond to the lumbar support fully relaxed (full-off) and fully tensioned (full-on) conditions respectively. As the drive mechanism moves towards the fully contracted condition, a first part of that mechanism moves relative to a second part so as to reduce the overall size of the mechanism, and each said part also moves relative to a mounting to which the drive mechanism is attached. By way of example, the first part may move into and out of the second part so as to vary the size of the mechanism in much the same way as occurs with a collapsing telescope. In one particular the drive mechanism includes a drive spindle having two coaxial parts, one of which moves axially into the other as the drive mechanism contracts. It is preferred that the mechanism is mechanical in nature, and it further preferred that the mechanism is essentially a screw mechanism.
According to one form of the invention, the screw mechanism includes an outer spindle part and a coaxial inner spindle part which are rotatable relative to one another and which are also movable axially relative to one another. The outer spindle part is tubular and has both an external screw thread and an internal screw thread, and those threads are of different hand. The inner spindle part has an external screw thread which matches and cooperates with the internal thread of the outer part. The internal thread of the outer part cooperates with an internal thread of a nut or the like which is held against rotation with the outer spindle part and which may form part of or be attached to the aforementioned mounting. In the installed condition of the mechanism, the inner spindle part is also held against rotation with the outer spindle part.
The arrangement is such that rotation of the outer spindle part in one direction relative to the cooperable nut causes that part to move axially in a particular direction. At the same time cooperation between the engaging threads of the outer and inner parts causes the non-rotating inner part to be moved axially relative to the outer part in the same direction as that in which the outer part is moving. The result is that the overall axial length of the drive spindle is either extended or reduced according to the direction of rotation of the outer part of the spindle. Furthermore, such extension or reduction results from two components of movement. One is the axi
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Derwent Abstract Accession No. G2340 B/29, Class Q14, SU, 513611, A (Bremshey AG) 9 Aug. 1978.
Barfield Anthony D.
Henderson's Industries Pty Ltd.
Jr. Milton Nelson
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