U.S. patent number RE30,648 [Application Number 05/912,233] was granted by the patent office on 1981-06-16 for chair for dental patients.
This patent grant is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Walter Hetz, Wilhelm Ohlrogge.
United States Patent |
RE30,648 |
Ohlrogge , et al. |
June 16, 1981 |
Chair for dental patients
Abstract
A chair for dental patients has a lower portion and an upper
portion including a swingable back and a seat movable when the back
is swung. The seat is connected at its rear end by a hinge with the
lower end of the back. The invention is particularly characterized
in that the seat is mounted upon the lower portion so as to be
movable in the longitudinal direction of the chair, while the back
is guided over a rigid guide which is connected with the lower
portion and the back. Means are provided in the part of the seat
free from the hinge between it and the lower portion which are
operable when the back is swung to tip the seat about a horizontal
axis toward the back.
Inventors: |
Ohlrogge; Wilhelm
(Uelzen-Veerssen, DE), Hetz; Walter (Erlangen,
DE) |
Assignee: |
Siemens Aktiengesellschaft
(Berlin & Munich, DE)
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Family
ID: |
5816882 |
Appl.
No.: |
05/912,233 |
Filed: |
June 2, 1978 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
264211 |
Jun 19, 1972 |
03806192 |
Apr 23, 1974 |
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Foreign Application Priority Data
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Aug 16, 1971 [DE] |
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2141022 |
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Current U.S.
Class: |
297/318;
297/411.44 |
Current CPC
Class: |
A47C
1/02 (20130101); A61G 15/02 (20130101); A47C
1/04 (20130101) |
Current International
Class: |
A47C
1/00 (20060101); A47C 1/02 (20060101); A47C
1/04 (20060101); A61G 15/00 (20060101); A61G
15/02 (20060101); A61G 015/00 () |
Field of
Search: |
;297/318,317,322,330,76,68,417 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Zugel; Francis K.
Attorney, Agent or Firm: Hill, Van Santen, Steadman, Chiara
& Simpson
Claims
What is claimed is:
1. A chair for dental patients, comprising a lower portion and an
upper portion, said upper portion having a back, a seat, and a
hinge connecting the lower end of said back with the rear end of
said seat, said upper and lower portions having means for
supporting and moving said seat in a longitudinal direction, said
means including crosshead .[.guides.]. .Iadd.guide assemblies,
.Iaddend.one part of .Iadd.each of .Iaddend.said crosshead
.[.guides.]. .Iadd.guide assemblies .Iaddend.being connected with
the seat and the other part with the lower portion, .[.the chair.].
.Iadd.said means .Iaddend.having rods with ends connected about a
horizontal axis transverse to the longitudinal axis of the chair
with said back and other ends connected with said lower portion,
.Iadd.at least one of the rods providing an arm support for the
chair, .Iaddend.and means interposed between said seat and said
lower portion and away from said hinge for tipping said seat about
a horizontal axis toward said back when said back is inclined.
2. A chair in accordance with claim 1 wherein the second-mentioned
means comprise a curved member and a roller guide engaging said
curved member.
3. A chair in accordance with claim 1 wherein the second-mentioned
means comprise a supporting arm pivotally connected with said seat
and said lower portion.
4. A chair in accordance with claim 2, wherein said curved member
is so shaped that the tipping of the seat begins when the back is
inclined by more than 25.degree. to the vertical.
5. A chair in accordance with claim 3, wherein said supporting arm
is of such length and so connected that the tipping of the seat
begins when the back is inclined by more than 25.degree. to the
vertical.
6. A chair in accordance with claim 3, .[.comprising.].
.Iadd.wherein the crosshead guide assemblies including
.Iaddend.crosshead guides having a horizontal guiding way and
.Iadd.being .Iaddend.carried by said lower portion, .Iadd.and
.Iaddend.said supporting arm .Iadd.being connected with a crosshead
or longitudinal displacement within the guiding ways. .Iaddend.
7. A chair in accordance with claim 3, comprising a common bearing
upon said lower portion for said rods and said supporting arm.
8. A chair in accordance with claim 6, .[.comprising.].
.Iadd.wherein said crosshead comprises .Iaddend.a sliding block
movable upon said crosshead guides and constituting a bearing for
said supporting arm and said rods.
9. A chair in accordance with claim 1, wherein said upper portion
comprises a seat part, a leg supporting part and a rotary hinge
interconnecting said parts, a curved member carried by said leg
supporting part and a roller member carried by said lower portion
and engaging said curved member to swing said leg supporting part
about said rotary hinge when said seat is moved longitudinally.
10. A chair in accordance with claim 9, wherein said curved member
is adjustable. .[.11. A chair in accordance with claim 1,
comprising a rotary drive for inclining said back and having a
driving axle coinciding with
the connection of said rods with said back..]. 12. A chair in
accordance with claim 1, wherein said rods .[.constitute arm
supports,.]. .Iadd.includes .Iaddend.cardan joints connecting said
rods with said back
and said lower portion. 13. A chair in accordance with claim 1,
wherein said .Iadd.crosshead guide assemblies include
.Iaddend.crosshead guides having sliding bearings.
Description
This invention relates to a chair for dental patients having an
inclinable back and an adjustable seat. The invention is
particularly concerned with a chair for dental patients having a
lower portion and an upper portion including a swingable back and a
seat movable upon the lower portion in the longitudinal direction
of the chair when the back is swung and connected at its rear end
by a hinge with the lower end of the back.
Treatments and working methods developed during the recent years in
dental medicine place certain requirements upon a dental patients
chair. Thus the chair must be adapted for the seated patient as
well as for a lying patient including all intermediate positions
and the different working positions of the dentist (direct or
indirect manner of working) must be also taken into
consideration.
It is known, as far as patients chairs of the usual type are
concerned, that when the back is raised (for example, for bringing
a patient from a lying position to a sitting position which is
necessary when treatment of the lower .[.jar.]. .Iadd.jaw
.Iaddend.follows that of the upper jaw) the distance of the head of
the patient from the dentist and from the instruments is changed.
The result is that the dentist not only has to change his working
position but must also adjust the location of the instruments,
plates, lights, etc.
To avoid these drawbacks patients chairs have been developed
wherein the seat is moved in the longitudinal direction of the
chair when the back is inclined or raised. When the back is raised
the head of the patient sitting upon the chair does not move
circularly any more,--with the hinge connecting the back with the
seat as the rotary axis,--but is moved only vertically. The
distance of the mouth of the patient to the instrument and the
dentist or his assistant remains substantially the same.
For this purpose, a known examining and treating chair has a back
provided with a running surface and an outer support with rollers
located between them which are arranged on a fixed link connected
with the base. The seat which is connected with the back by a
hinge, is moved upon a sliding surface when the back is
inclined.
This chair construction has, among others, the drawback that the
fixed link and the running surfaces for the rollers require a
comparatively large space behind the back, so that freedom of knee
movement for the dentist and his assistant is greatly limited,
particularly in a sitting working position and when the back is
inclined rearwardly to a great extent.
An object of the present invention is to improve existing
constructions.
Another object is the provision of a chair for dental patients
which can be used in a large number of ways and which nevertheless
has a simple structure.
A further object is the provision of a chair well suited for
treating lying patients in modern ways.
For that purpose it is necessary that the rear side of the back
should be substantially free from guiding and supporting parts for
the back and the seat, so that it should be as flat as possible and
provide great freedom for the knees of the dentist. However,
advantages of known chair constructions should be fully retained
wherein when the position of the chair is changed, the distance of
the dentist or his assistant from the mouth of the patient is
substantially unchanged, so that no corrections are necessary when
the treating position is changed. Furthermore the adjusting
mechanism of the chair parts should be operated as easily as
possible.
Yet another object of the present invention is to construct a chair
for dental patients in such manner that the patient can assume a
relaxed and convenient position thereon in all lying and sitting
positions. This is particularly necessary for working positions
wherein the back is inclined rearwardly to a very large extent
(fully indirect treating position with a lying patient). In that
position the patient can easily get the feeling of helplessness
which can then cause him to assume a cramped position.
Other objects of the present invention will become apparent in the
course of the following specification.
In the accomplishment of the objectives of the present invention it
was found advisable to mount the seat upon the base so that it is
movable in the longitudinal direction of the chair, while the back
is guided over rigid rods which are connected with the base and the
back. Furthermore, means are provided in the part of the seat
between it and the base which are operable when the back is
inclined to tip the seat about a horizontal axis toward the
back.
This construction of the present invention provides a substantial
advantage over known chair constructions as far as the location of
the patient is concerned. Due to this construction the patient has
a secure hold even in an extreme lying position (with the head
practically horizontal), since his body will not lie in a
completely stretched position, but his legs will be somewhat bent
relatively to his body due to the slight tipping of the seat.
Thus the construction of the present invention makes it possible
.[.chair..]. .Iadd.to .Iaddend.couple the movements of the back and
the seat as a tipping and at the same time to carry out a
longitudinal movement of the lower part of the .[.chari.].
.Iadd.chair.Iaddend.. The structural depth of the back does not
have to be increased for this purpose. By coupling three movements
of the chair with each other substantial advantages are produced
since only a single drive is required for actuating the chair. The
resulting advantages consist not only in smaller manufacturing
costs, which are particularly high in program-actuated chairs,
since here only a single operating circuit is required, but they
also provide servicing advantages. The dentist can actually operate
the three chair movements by actuating a single button, providing
the adjustment of the entire upper chair portion. On the other
hand, in case of individual drives, he would have had to operate
separately the three movements and to adjust them relatively to
each other. A further advantage consists in the simple structure of
the chair, particularly the setting mechanism.
The construction of the present invention solves the problem of
eliminating to a great extent relative movements between the back
of the patient and the supporting surface of the back when the back
is swung, without it being necessary to shift the rotary axis of
the back greatly forwards and upwardly, as is often the case in
known patients chairs.
It is advantageous to provide the movable support of the hinge upon
the upper part of the chair in such manner that either the hinge is
mounted upon a straight guide with a horizontal guide path provided
upon the lower part of the chair, or that the hinge is mounted by a
rod upon the lower part of the chair. In case of the
first-mentioned construction it is advantageous to make the
straight guide as a slide guide .Iadd.or crosshead guide of a
crosshead guide assembly.Iaddend..
Means for tipping the seat when the back is inclined can consist
advantageously of a supporting arm arranged between the seat and
the lower part of the chair. The arm supports the seat when the
back is inclined relatively to the lower part and tips the seat
toward the back. A further advantageous embodiment consists in
providing a curved member upon the seat or the lower part of the
chair in the seat part free from the hinge for the tipping of the
seat, a roll member or the like being used as a support of the
chair lower part or the seat engaging the curved member.
In accordance with a further embodiment of the present position the
best possible lying position is attained when the curved member is
so shaped, or according to another suggestion, when the size of the
supporting arm or its attachment are so selected, that the tipping
of the seat starts only when the back is inclined by more than
25.degree. to the vertical.
The hinge of the rigid guide belonging to the lower part of the
chair as well as that of the supporting arm can be combined into a
slide stone movable along a straight guide.
The invention will appear more clearly from the following detailed
description when taken in connection with the accompanying drawing
showing by way of example only, preferred embodiments of the
inventive idea.
In the drawing:
FIG. 1 is a simplified side view of a chair for dental patients
constructed in accordance with the present invention.
FIG. 2 is a side view of a somewhat differently constructed
chair.
FIG. 3 is an enlarged side view of a part of a mechanism shown in
FIG. 2.
FIG. 4 is a side view of another chair construction.
FIG. 5 is a side view of yet another chair construction.
In all Figures the same parts are indicated by the same
numerals.
FIG. 1 shows a chair for dental patients having a base 1 and a
lower chair portion 2 adjustable in height relatively to the base.
The lower chair part 2 carries a back 3 and a seat 4 which jointly
form the upper part of the chair. The rear end of the seat 4 is
connected by a hinge 5 with the back 3. The hinge 5 .Iadd.is a
crosshead of a crosshead guide assembly and .Iaddend.is supported
in a straight .[.guide 11.]. .Iadd.guide or crosshead guide 11 of a
crosshead guide assembly .Iaddend.mounted upon the lower chair part
2 to provide longitudinal movement of the seat 4. The straight
guide 11 has a substantially horizontal guiding path.
In the drawing the guide 11 is supposed to represent a slide guide.
Obviously the slide guide can be replaced by a roller guide.
The back 3 is guided by rods 6 and 8, the rod 6 being pivoted at 7
to the lower chair part 2 while the rod 8 is connected by the pivot
9 with the back 3. The rods 6 and 8 are rigidly interconnected. The
seat 4 is swingably connected in the part free from the hinge 5
with the lower chair portion 2 by a supporting arm 40. Pivots
attached to the ends of the arm 40 are indicated as 41 and 42. It
is apparent from the drawing that when the back 3 is inclined, the
entire upper chair part 3, 4 is movable upon the straight guide 11.
The supporting arm 40 is of such length and the pivots 41 and 42
are so arranged that when the back 3 is inclined in the direction
of the arrow, the seat 4 is easily raised toward the back.
Obviously, when the back is raised the seat is lowered. The easy
raising of the front part of the seat (foot support) when the back
is inclined provides a particularly good hold and seating without
tension for a patient sitting upon the chair. As shown in the
drawing, the tipping takes place about an axle 5 common to back 3
and seat 4.
The arrangement of the pivot 9 along the back need not be that
shown in the drawing. Obviously it must not coincide with the hinge
5. Preferably the pivot 7 and pivot 50 of FIG. 3 are so arranged as
far as their height is concerned that when the back is lowered to a
great extent an imaginery straight line .[.extruding.].
.Iadd.extending .Iaddend.between the pivots 9 and 7, or between
pivots 9 and 50 will be always located above the hinge 5. The end
pivots of the hinge are constructed as slide stones .Iadd.or
crossheads .Iaddend.which can easily move in the path of the
straight guide 11. The rigid rod connection 6, 8 serves at the same
time as an arm support and is arranged on both sides of the chair.
One of these arm supports is preferably so constructed that its
rods can be changed by simple manipulation from a rigid condition
to a non-rigid condition so that the arm support can be moved to a
position which will help the patient to get off the chair. For that
purpose the rods can be made of two parts and provided with a
lockable coupling member permitting the rods to be rigid in a
coupled condition and swinging them into an open position when
uncoupled.
In the embodiment shown in FIG. 5 the pivots 9 and 7 are
constructed as cardan joints with both cardan axes extending in the
direction of the connection 7-9. This arrangement makes possible a
single side swinging of the arm support into a get off position
(about the diagonal 9-7 of the rectangle 9, 5, 7, 12 as the
swinging axis), so that it is not necessary to provide a special
device, such as a telescopic support or the like for this purpose,
as is the case in prior art arm supports. From the drawing it is
apparent that in a folded position the arm 9-12 of the arm support
substantially covers the side 9-5 of the back and the arm 12-7
covers the side 5-7. Thus when the arm support is folded the
patient can easily leave the chair. A further advantage consists in
that the arm support can be folded inwardly to some extent and thus
provide a better hold, particularly for small children.
The construction of the present invention makes it possible to
provide good compensation for forces exerted in different
directions by the weight of the patient upon the chair. It is
apparent from the drawing that forces acting upon the back have the
tendency of moving the chair forward (toward the foot end of the
chair), while the forces upon the inclined rising seat have the
tendency of moving the chair rearwardly (toward the head end of the
chair). The two forces are opposed and nearly balance each
other.
In the embodiment illustrated in FIGS. 2 and 3 the pivots 50 and 51
used to support the arm 8 and the arm 40 holding the seat 4 upon
the chair lower part 20, are combined into a common slide .[.stone
52.]. .Iadd.stone or crosshead 52 of a crosshead guide
assembly.Iaddend.. As shown in FIG. 3, the slide stone 52 is
movable in a straight guide .Iadd.or crosshead guide .Iaddend.53
having a horizontal guide path .Iadd.or guiding way .Iaddend.and
carried by the chair lower part 20. The guide 53 is so arranged
that the arm 40 raises the seat 4 only when the back 3 has been
inclined by more than 25.degree. relatively to the vertical. Thus
the tipping movement of the seat is retarded relatively to the
movement of the back.
The movement of the chair starting with a steep position of the
back takes place as follows:
The initial position of the seat is combined with an inclination of
the back of about 15.degree. to the vertical. This was found to be
a particularly good position when a patient is getting off. When
the back 3 is now inclined the seat 4 is initially moved only in
the longitudinal direction. At a certain position of the back
(about 25.degree. to 35.degree.) the slide stone 52 reaches its
counter support in the guide 53. When the back 3 is further
inclined from this position the seat 4 begins to rise toward the
back by means of the arm 40 swinging about the .[.axle 5.].
.Iadd.axle 51.Iaddend..
The embodiment of FIG. 4 shows other means for coupling the tipping
of the seat 4 with the movement of the back 3. In this construction
the pivoted arm is replaced by a curved member 60 .Iadd.(for
purposes of illustration is shown as a substantially straight
member) .Iaddend.located upon the lower part of the seat 4 and
supported by a roller guide 62 fixed upon the lower chair portion
61. The angle of inclination of the curved member 60 can be changed
by an adjusting screw 63 or the like, so that the tipping (rising)
of the seat depending upon the inclination of the back can be
adjusted individually.
Obviously, the curved member 60 can be also fixed upon the lower
chair portion 61 while the roller guide 62 can be attached to the
seat.
It was found advantageous to embody the required profile of the
curved member 60 into the lower outline of the seat 4. The profile
is advantageously so shaped that the ratio of the inclination of
the back to the rising of the seat amounts to 3:1 to 2:1.
FIG. 5 shows an embodiment of the patients chair of the present
invention wherein the seat is made of two parts, namely, it is
divided into a seat support 70 and a leg support 72 connected with
the seat support by a rotary hinge 71. The leg support 72 is
provided with a curved member 73 which is also supported by a
roller guide 74 connected with the lower chair portion 61. The
curved member 73 is so arranged or its inclination can be adjusted
in such manner that the leg support 72 is raised by a predetermined
amount for a predetermined position of the back.
It should be also noted that the straight guide for the hinge 5
shown in the drawings does not have to be necessarily a horizontal
guide path. It is possible within the scope of the present
invention to make the guide path somewhat inclined to the
horizontal, namely, in such manner that when the hinge 5 is moved
longitudinally (when the back is inclined) the seat 4 is moved upon
an inclined plane provided by the inclined guide path in the
direction of a tipping seat movement.
As far as operation is concerned, it should be noted that the
present invention solves the problem of adjusting the chair with
small operational forces. According to the constructions of the
present invention the upper chair part is well balanced in all
positions. As already described, even when a patient is sitting on
the chair, the balancing of the upper part of the chair is
provided, since forces exerted upon the back substantially balance
the forces exerted upon the seat consisting of a seat support and
leg support. The resulting advantages consist in that the upper
chair part can be also adjusted by hand and if a drive is provided,
it must have only a comparatively small output.
Advantageously, a rotary drive can be provided for operating the
chair which, for example, engages the hinge 5 or 9 and causes the
swinging of the back. It is also possible to provide a straight
drive, such as a hydraulic or pneumatic piston drive, which engages
the seat as a suitable location of the straight guide.
As far as the technical structures of the slide guides 11, 21, 52
and 53, as well as the hinges 7, 9, 41, 42, 50 and 51, and the
roller guides 62 and 74 are concerned, they are all usual parts
readily available on the market, so that further description of
these parts within the scope of the present invention is believed
unnecessary.
It is also within the scope of the present invention to so
construct the chair upper part receiving the hinges 5, 7, 42, 50
and 51 that in addition to adjustment in height it is swingable
about an axis parallel to the longitudinal axis of the chair. In
that case an intermediate carrier is necessary which would be
preferably arranged between the horizontal part and the vertical
part of the lower chair part 2 adjustable in height in the base
1.
For the purposes of the present invention it is immaterial whether
the hinge connecting the back with the seat is shiftable in a
longitudinal guide. Actually means supporting the seat in the
longitudinal guide can be provided at any desired suitable
place.
* * * * *