Note: Descriptions are shown in the official language in which they were submitted.
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The invention concerns a back support for bath lifts which feature a baseframe, a
seat plate and an interposed lifting frame with lifting mechanism, said back support
having a base element which can be placed on and fixed to the seat plate, pivot-mounted on which base element is a backrest which can be swivelled downwards
5 and backwards around a first transverse axis from an inclined position to a flat
position, and which is supported at least in the inclined position by a support element
mounted on the base element and on a tee web protruding from the rear of the
backrest.
A back support of this species is known from EP-A-0622042. The support element
consists of a hose section which can be filled with pressure water. A separate
manually operated control valve is necessary for filling and emptying the hose
section.
A simpler back support is known from EP-B-0347652, in which a latching device isintegrated in the pivot bearing of the backrest which enables the backrest to belocked in any number of finely graduated inclined positions. The backrest must be
moved in the direction of the pivot axis against a spring in order to unlatch it. This
unlatching operation can certainly be performed by an assistant; however, the
20 disabled person sitting on the seat plate is rarely able to carry out this manoeuvre.
A back support is revealed in EP-A-0578947 in which inclination cams formed on the
side of the seat serve to guide the backrest such that at least two different angles of
inclination can be set, and the backrest can be folded over completely forwards and
25 backwards. The backrest is latched in the inclined positions. In order to unlatch the
backrest, it has to be raised so that it may be moved into the other inclined position
or one of the flat positions. This unlatching operation also generally requires the help
of an assistant.
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The object of the invention is to improve a back support of the species mentioned at
the beginning such that it can be moved by simple means from the supported inclined
position to a flat position and vice versa, and that the disabled person can perform
this adjustment operation himself or herself.
This objective is achieved with a back support of the species mentioned at the
beginning in that the tee web is arranged in a vertical plane at right angles to the
backrest and exhibits a guideway into which the runner arranged at the top of a
swivel arm engages, that the swivel arm is pivot-mounted around a second
10 transverse axis on the base element, which transverse axis is located at a certain
distance from the first transverse axis, and that the guideway incorporates a track
section extending upwards at least approximately along the length of the backrest,
which track section exhibits a bottom portion to which is allocated a bypass track
section which forms a track loop. This track loop is designed such that the bottom
15 end of the long track section and of the bypass track section join in a connecting
track section such that the bypass track section rejoins the long track section at a
vertical distance from the connecting track section, and that a non-return stop is
allocated to at least one of the junctions.
20 The swivel arm constitutes the support element. When the backrest is moved to a
more upright position, the swivel arm pivots upwards and forwards, with its runner
sliding downwards in the long track section of the guideway until it reaches theconnecting track section. Once the runner has come to a stop at the front of theconnecting track section, the swivel arm supports the backrest in the inclined
25 position. In order to adjust the backrest from this inclined position to a flat position,
the backrest merely needs to be briefly lifted so that it rotates forwards, as a result of
which the runner moves to the rear of the connecting track section where, on passing
over the non-return stop, it enters the bypass track section. The backrest can now be
slewed unhindered backwards to a flat position in which it is supported against the
30 wall of the bath tub. In this process, the runner of the swivel arm passes through the
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bypass track section and enters the long track section at its top junction. Above this
top junction, i.e. that point at which the long track section branches into its bottom
portion and the bypass track section, the runner moves downwards as the backrest is
lifted, and as the backrest is lowered, it moves upwards. In the bottom portion of the
5 long track section, the runner can only move downwards, and in the bypass track
section it can only move upwards.
According to one embodiment, the long track section is unrestricted at the top so that
the backrest is supported at the base element or the seat plate of the lift. A further
10 development of the invention provides for the insertion of a mechanical stop in the
guideway where it may be secured by a positive locking means against
displacement, so as to obtain a certain flat position for the backrest with a defined
angular setting. The runner then supports the swivel lever via this mechanical stop
on the backrest. The mechanical stop is preferably of plate-shaped design and
15 engages in transversely aligned slots in the guideway. Several slot pairs may be
provided at small longitudinal intervals in order to achieve finely graduated
adjustment settings for the flat position of the backrest.
In the simplest case, the bottom section of the long guideway forms together with the
20 bypass track section and the connecting track section a parallelogram-like or even
rectangular arrangement in which the individual track sections do not necessarily
have to run in a straight line. By clever selection of the junction devices for the track
sections at the joining points, it can be ensured that the runner, when passing
through a track junction, always enters the required track section as its motion cycle
25 continues, even when there is no non-return stop. Provision of several non-return
stops can also ensure achievement of this objective.
According to a further development of the invention, the runner may be designed as
a pin loaded by a compression spring. The guideway then consists of a slot
30 arrangement and the non-return stop is designed in the form of a shoulder in the slot
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bottom. The slot bottoms of the major part of the slot arrangement lie in this case in a
common plane, and each shoulder is preceded by an upward rising ramp. Each
shoulder exhibits a step face running at least approximately at right angles to the slot
bottom, which face is flush with a side face of a connecting track section.
Where the runner is located in the connecting section, the end points of the
connecting track section form a straight line which, with the longitudinal centreline of
the swivel arm, form an included angle of max. 45~. In a preferred embodiment, this
angle is less than 10~.
Finally, a further development of the invention provides for the long track section
joining at the bottom a short end section which is angled in respect of the backrest,
allocated to which junction is a first non-return stop, this end section in turn joining at
an angle with the connecting section, to which second junction is also allocated a
15 non-return stop. The short end section preferably forms a right angle with the long
track section. This ensures that any upward movement of the backrest is
automatically stopped once the runner enters the short end section of the long track
section. A brief backward movement of the backrest then enables the runner to move
to the front end of the connecting track section where it then supports the backrest in
20 its inclined position.
The tangent placed on the bypass track section at its junction with the connecting
track section forms an angle greater than 90~ with the swivel arm centreline
extension if the runner is located at this junction. This angle only needs to be slightly
25 greater than 90~ in order to avoid jamming.
A particularly advantageous feature of the invention lies in the fact that, arranged
coaxially to one of the two rotational axes, preferably the swivel arm axis, is a leg
spring which is loaded when the backrest is moved down, the resultant spring power
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being sufficient in order to return the released backrest at least approximately to its
inclined position. The disabled person therefore only needs to raise his or her upper
body from the Iying position, and the integrated spring will then ensure that the
backrest follows. The backrest either finds its inclined position of its own accord or
5 this position is reached when the back of the occupant is placed against the
backrest. The disabled person is provided with a safe and secure support at the
backrest as the seat plate of the lift is raised and lowered, and he or she can release
the backrest by performing a simple releasing action to lower it into its flat position,
the backrest in this case being moved slightly forward until the runner on the swivel
10 arm has passed the non-return stop. This release action applied to the backrest is
particularly easy to perform if an additional operating lever is provided at the backrest
which points forward so that it only needs to be pushed downwards by the disabled
person. This operating lever is preferably arranged on the side of the backrest and
pivot-mounted so that it only needs to be swivelled into its operating position, defined
15 by a mechanical stop, when it is required, otherwise remaining concealed in its
resting position behind the front surface of the backrest.
The invention is explained in more detail by way of example on the basis of the
drawing, wherein:
FIG. 1 shows a bath lift in an exploded representation, with a back support according
to the invention;
FIG. 2 shows a rear view of the left half of the back support;
FIG. 3 shows a side view of a runner of a swivel arm engaging in the slotway of the
back support;
FIG. 4 shows a view of the slot arrangement in a tee web on the backrest;
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FIG. 5 shows a longitudinal cross-sectional view through the slotway along the line 5-
5 of Figure 4;
FIG. 6 shows a cross-sectional view through the slotway along the line 6-6 of Figure
5 4;
FIG. 7 shows a view of a modified slotway;
FIG. 8 shows a cross-sectional view along the angled line 8-8 of Figure 7;
FIG. 9 shows a side view of the back support.
The main components of the bath lift according to FIG. 1 are a baseframe 10, a seat
plate 14, a guide frame 16 and a hydraulic lifting hose 18 which can be filled with
15 pressure water. A detachable back support 20 is fixed to the seat plate 14. The back
support 20 exhibits a base plate 22 which rests on the seat plate 14, and at the front
a back rest 24 which is pivot-mounted around a first transverse axis 26. A plate-
shaped swivel arm 28 is pivot-mounted around a second transverse axis 30 at the
rear of the baseplate 22, and engages in two coaxial, outboard pins 32 in respective
20 slotways 34 which are formed internally at two tee webs 36, these in turn being
integrally formed in, or fixed to the rear face of the backrest 24.
The slotway 34 has, according to FIG. 3, a stepped cross section in which a shoulder
38 is formed to which adjoins a recessed portion forming the slot bottom 40. The25 runner 32 exhibits a sleeve 42 which protrudes laterally out of the plate-shaped
swivel arm 28 and engages in the slotway 34 up to the shoulder 38. Mounted in the
sleeve 42 is a sliding pin 44 which is pressed outwards by a helical compressionspring 46, the end face of which pin 44 rests on the slot bottom 40 in the recessed
slot portion.
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The slotway 34 exhibits a first long track section 48 which essentially extends along
the backrest 24 closely adjacent and parallel to the rear face of the backrest. This
long track section 48 is slightly angled at the bottom towards the rear in order to
create space for a short end section 50 which adjoins it at right angles. This end
5 section 50 ends at a connecting track section 52 which, together with the angled end
50 of the long track section 48 forms an angle of approx. 45~. This connecting track
section 52 in turn ends at the end away from the backrest 24 in a bypass track
section 44 which, apart from slight curvatures, extends along the long track section
48 and joins this at an acute angle. Provided at the end of each track section, i.e.
10 where each track section joins the next track section, is a non-return stop 56
consisting of a shoulder 58 which extends down to the slot bottom 40 and which is
preceded by a ramp 60.
As the backrest 24 is raised from the flat position indicated as a broken line in FIG. 9,
15 the two runners 32 slide down the long track sections 48 of the two slot arrangements
34. In the area of the ramp 60 in front of the first non-return stop 56, the pin 44 is
pushed into the sleeve 42 and then latches behind the shoulder 58 in the recessed
part of the angled end section 50. The backrest 24 is thus prevented from any further
upward movement. Moving the backrest 24 down slightly results in the runners 32
20 overcoming the second non-return stop 56 at the top end of the connecting track
section 52 so as to define the inclined position of backrest 24. In order for the
backrest 24 to return to its flat position, it must first perform a forward releasing
movement. This causes the two runners 32 to travel to the bottom of the connecting
track section 52 and, after overcoming the third non-return stop 56, to pass into the
25 start of the bypass track section 54. This thus limits the forward release movement of
the backrest 24. The backrest can then be swivelled backwards, whereupon the
runners 32 travel upwards in the bypass track section 54 and, after overcoming the
fourth non-return stop 56, pass into the long track section 48 in which they then slide
upwards.
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It is essential that none of the track sections 48, 50, 52, 54, or any parts thereof,
extend at right angles to the swivel arm 28 when its runners 32 are located in these
respective sections. It is also important in respect of the bottom end of the bypass
track section 54 according to FIG. 4 that the swivel arm 28 is located at a very steep
5 angle. Where the distances between the two transverse axes 26, 30 are relatively
large, so producing a more horizontal position for the swivel arm 28 when its runners
are located at the bottom of the bypass track section 54, the bypass track section 54
must be steeper, at least at its bottom end, i.e. almost parallel to the backrest 24,
because an obtuse angle between the swivel arm 28 and the bypass track section 54
10 must always exist in order to prevent the system from jamming.
Needless to say, it is not necessary that a non-return stop 56 be provided - as
illustrated - at each junction. Because of its weight, the plate-shaped swivel arm 28
tends to swivel in the direction of the backrest anyway once the runners 32 reach the
15 lower part of the long track section 48. If the swivel arm 28 is additionally equipped
with a reset spring which exerts a slewing torque acting in the same direction as the
gravity pull, the first non-return stops 56 at the ends of track sections 48 and 50, and
also 54 need not be provided. Only non-return stop 56 at the junction between the
connecting track section 52 and the bypass track section 54 is obligatory.
Figures 7 and 8 show a somewhat modified slotway 34 in which the long track
section 48 directly joins the connecting track section 52 without the angled endsection 50. The slotway 34 is thus rendered simpler in design, although the system
becomes slightly less easy to use because, when the backrest 24 is raised, it is no
25 longer automatically stopped but could rather continue its upward travel until the
runner 32 enters the bypass track section 54. This can, however, be easily
prevented, as on overcoming the non-return stop 56 at the end of the long track
section 48, the pins 44 of the runners 32 engage in the slot recesses with an audible
click. The user thus receives an audible signal indicating the end of the upward travel
30 of the backrest 24, so enabling him or her, by immediately reversing the backrest
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swivel motion, to cause the runners to pass upwards into the extension of connecting
track section 52. This extension section, designated 52', is a safety measure which
prevents the swivel arm 26 from being accidentally released in the event of the
backrest 24 being slightly rotated.
