[0001] The invention relates to a liquid sprayer for a dishwasher. The invention further
relates to a dishwasher with a liquid sprayer.
[0002] The prior art document
WO 2020/057821 A1 discloses a dishwasher with a liquid sprayer that comprises a first arm, which is
rotatably mounted to a base body, and a second arm, which is rotatably mounted to
the first arm. A transmission device couples the rotational movement of both arms.
It is a disadvantage that food residues or increasing calcification can easily block
the rotating movement of such a liquid sprayer and that the eccentric bearing of the
spray arm causes vibrations.
[0003] An object of the present invention is to provide an enhanced liquid sprayer, which
is particularly reliable in application and particularly time, water and energy saving.
[0004] This object is achieved in accordance with the invention by a liquid sprayer having
the features set out in claim 1. It was found according to the invention, that a liquid
sprayer comprising a drive arm, a spray and a transmission device, which couples the
rotational movement of the drive arm and the spray arm, is particularly reliable in
application as well as time, water and energy saving, when the drive arm comprises
at least one drive nozzle for driving the drive arm in rotation about the base axis
and when the transmission device is configured such that a drive arm rotation rate
is in absolute value at minimum as large as a spray arm rotation rate. The rotation
rates of the drive arm and the spray arm are determined in a stationary coordinate
system. Preferably, the base body is rigidly fixed to that stationary coordinate system.
The rotation rate can be specified in revolutions per second. The drive arm rotation
rate is determined by the drive arm's speed of rotation about the base axis. The spray
arm rotation rate is determined by the spray arm's speed of rotation about the drive
arm axis. That the drive arm rotation rate and the spray arm rotation rate are compared
in absolute values means that the direction of rotation should not be taken into account,
only the rotation rate. Preferably, the rotational movement, in particular the rotation
rate, of the spray arm and of the drive arm are coupled linearly to each other, such
there is a linear dependency between both rotation rates. The drive nozzle for driving
the drive arm is preferably a nozzle for ejecting washing water. The drive nozzle
can be aligned such that the ejection of the washing water results in a drive torque
on the drive arm about the base axis. Since the transmission device is configured
such that the drive arm rotation rate is at least as large as the spray arm rotation
rate, the drive torque which is applied to the drive arm, causes a spray arm torque,
which is at least as large as the drive torque. Thus, particularly high spray arm
torques can be achieved. Due to this increased spray arm torque, the rotational movement
of the liquid sprayer is more robust against soiling and calcination. The liquid sprayer
is particularly reliable in use. Due to reliably dispensing the washing water uniformly,
the liquid sprayer is particularly time, water and energy saving. The reduced rotational
speed of the spray arm, especially when supported eccentrically to the base axis,
results in reduced vibrations and a longer service life of the liquid sprayer.
[0005] According to an aspect of the invention, the liquid sprayer, particularly the drive
arm and/or the spray arm, are driven in rotation solely by means of drive nozzles
for ejecting washing water. The drive arm and/or the spray arm preferably comprise
at least one, particularly at least two, particularly at least three, and/or at most
six, particularly at most five, drive nozzles.
[0006] More preferably, only the drive arm comprises the at least one drive nozzle. Due
to avoiding motors, particularly electric motors and/or fluidic motors, for driving
the liquid sprayer, particularly the spray arm, the complexity of the liquid sprayer
can be further reduced. Such liquid sprayer is particularly robust in use and can
be manufactured economically.
[0007] Preferably, the at least one drive nozzle sprays the liquid in the direction of a
spray vector. The spray vector preferably comprises, in particular consists of, a
radial and/or a tangential and/or an axial vector component with respect to the base
axis. An angle between the axial direction, which is parallel to the base axis, and
a vector consisting of the tangential and the axial vector components of the spray
vector can be 30° to 150°, particularly 60° to 120°, particularly 75° to 105°, particularly
90°. An angle between the axial direction, which is parallel to the base axis, and
a vector consisting of the radial and the axial vector components of the spray vector
is preferably at most 30°, in particular 10°. More preferably, the radial vector component
of the spray vector is zero. The spray vector of the at least one drive nozzle can
be aligned to spray out liquid towards a carrier for dishes. The base axis and/or
the spray arm axis preferably enclose an angle with the vertical or the horizontal
direction of at most 30°, particularly of at most 20°, particularly of at most 10°.
More preferably, the base axis and/or the spray arm axis are aligned vertically or
horizontally.
[0008] According to a further aspect of the invention, the transmission device is configured
such that there is a constant or a non-constant transmission rate between the drive
arm rotation rate and the spray arm rotation rate. Preferably, the transmission device
comprises a gearbox. A non-constant transmission rate can for example be achieved
by gear wheels with a non-circular shape, particularly regarding its gear rim. A gearbox
with gear wheels that have a circular shape can be used to achieve a constant transmission
ratio. The transmission ratio is specified by the ratio between the drive arm rotation
rate and the spray arm rotation rate, particularly in the stationary coordinate system.
The transmission ratio preferably is in the range from -1:1 to +1:1, more preferably
from more than -1:1 to less than 1:1, more preferably from -1:3 to 1:3, more preferably
from -1:5 to 1:5.
[0009] Preferably, the base axis and the spray arm axis are spaced apart from each other.
The base axis and the spray arm axis preferably are aligned parallel and/or in a vertical
direction.
[0010] The spray arm preferably comprises at least one, particularly at least two, particularly
at least three, and/or at most four, particularly at most three, spray booms. The
at least two spray booms are preferably aligned perpendicular to the spray arm axis.
The spray booms can have different lengths perpendicular to the spray arm axis, particularly
when the spray arm comprises two spray booms. Thus, a particularly uniform distribution
of washing water can be achieved.
[0011] According to a further aspect of the invention, the transmission device is configured
such that the motion path of the spray arm is identical for each of its revolutions,
particularly about the spray arm axis. For achieving this, the transmission ratio
is preferably one of the values -1:3, 1:5 or 1:1. The washing water is thereby distributed
in the dishwasher, particularly in a washing chamber with a rectangular, particularly
square, base shape, more evenly. The motion paths are also referred to as trajectories.
Preferably, the trajectories of the at least one spraying nozzle and/or the at least
one drive nozzle are identical for each revolution of the drive arm and/or the spray
arm.
[0012] The transmission device is preferably a gearbox with at least two gear wheels. Such
transmission device is economic to manufacture and robust in use.
[0013] The base body preferably at least in sections is rotationally fixed, preferably completely
fixed, to the washing chamber of the dishwasher. The base body can comprise a drain
sump and/or a drain grid and/or a supply socket for conducting washing water to the
liquid sprayer and/or a gear wheel, particularly a base gear wheel, of the transmission
device. The liquid sprayer is preferably configured to be reversibly attached to the
base body. The base body can be reversibly attached to the washing chamber and/or
to the supply socket or be of one piece with them. Due to the reversible attachment
of the liquid sprayer to the base body and/or of the base body to the washing chamber,
the liquid sprayer is particularly easy to install or to replace.
[0014] A liquid sprayer as claimed in claim 2 is particularly robust in use. Preferably,
the drive arm rotation rate is in absolute value at least two times larger, more preferably
at least three times larger, more preferably at least four times larger, than the
spray arm rotation rate. Thereby, the resulting drive arm torque can be increased
further.
[0015] A liquid sprayer as claimed in claim 3 is particularly robust and durable. Due to
the rotation of the drive arm and the spray arm in opposite directions, particularly
with reference to the stationary coordinate system, bearing loads and/or vibrations
can be reduced. Due to the counter rotation of the drive arm and the spray arm, their
rotation rates can be reduced, while the transmission ratio can be set to at most
one in absolute value. The reduced rotation rates lead to decreased centrifugal forces
and thus reduced bearing loads and vibrations. The transmission device is preferably
configured to provide a transmission ratio of less than 0.
[0016] A liquid sprayer as claimed in claim 4 can be manufactured particularly economical
and is robust in use. Preferably, a base gear wheel is part of the base body and/or
attached to it in a rotationally fixed manner. The base gear wheel and the base body
can be one piece. A spray arm gear wheel is preferably rigidly attached to the spray
arm and/or integrally connected with it. The third gear wheel is preferably a drive
gear wheel, which is attached to the drive arm such that it can rotate relative to
the drive arm, in particular about a drive shaft axis. The drive shaft axis, the base
axis and/or the spray arm axis are preferably spaced apart from each other and/or
aligned parallel, in particular parallel to a vertical direction. With the at least
three interlocking gear wheels, the aforementioned transmission ratios, particularly
the counter rotation of the drive arm and the spray arm, can be achieved economically
and with the necessary robustness.
[0017] The transmission device preferably comprises at least three, more preferably at least
four, more preferably at least five, and/or at most six, particularly at most five,
interlocking gear wheels. The interlocking gear wheels can comprise straight-toothed
gear wheels and/or helical gear wheels. Helical gear wheels are particularly robust
in use and reduce vibrations. The transmission device is preferably configured such
that it is not self-locking. The transmission device preferably solely comprises gear
wheels with cylindrical, particularly circular cylindrical, gear rims.
[0018] The liquid sprayer as claimed in claim 5 can be maintained easily and is particularly
compact. Preferably at least one, more preferably at least two, more preferably all,
of the gear wheels are located outside the liquid duct and/or a hollow structure of
the drive arm and/or of the spray and/or outside a housing of the liquid sprayer,
in particular of the drive arm and/or of the spray arm. The at least one gear wheel
can be located such that it is wetted by the washing water, which is dispensed in
the washing chamber, particularly by means of the liquid sprayer. Thereby, the liquid
sprayer can be dimensioned more compact. Further, the gear wheels are lubricated by
the washing water.
[0019] According to a further aspect of the invention, the at least one gear wheel is detachably
mounted. Thus, it can be installed and/or replaced easily, in particular when it is
located outside the liquid duct, in particular outside a housing of the liquid sprayer.
[0020] A liquid sprayer as claimed in claim 6 is particularly flexible, robust and economic
in use. Preferably, a first drive gear wheel and a second drive gear wheel are rigidly
connected together, preferably by means of a drive shaft. Those drive gear wheels
can be rotatably mounted to the drive arm. Preferably, the first and the second drive
gear wheel are attached to the drive arm such that it can rotate about the drive shaft
axis. Due to the four interlocking gear wheels, the washing water can be dispensed
within the washing chamber more uniformly. Preferably, at least one of the drive gear
wheels are replaceable. Thus, different transmission ratios can be achieved, which
allow for the use of the liquid sprayer for dishwashers with different washing chamber
geometries, particularly with a different base shape.
[0021] The first drive gear wheel and the second drive gear wheel preferably have the same
number of teeth. Alternatively, they can comprise different numbers of teeth. The
base gear wheel and the spray arm gear wheel can have the same number of teeth or
a different number of teeth. According to an aspect of the invention, the number of
teeth of the drive gear wheels is less than the number of teeth of the base gear wheel
and/or the spray arm gear wheel.
[0022] According to a further aspect of the invention, the base gear wheel interlocks with
the first drive gear wheel. The first drive gear wheel and the second drive gear wheel
are rigidly connected to each other, particularly via a drive shaft. The drive gear
wheels are supported at the drive arm rotatably. In particular, the drive shaft is
preferably attached to the drive arm such that it can rotate about a drive shaft axis.
Preferably, the second drive gear wheel interlocks with the spray arm gear wheel.
With such a constellation, the transmission ratio can be calculated depending on the
number of teeth of the base gear wheel n
B, of the first drive gear wheel n
D1, of the second drive gear wheel n
D2 and of the spray arm gear wheel ns according to the following formulas

[0023] To achieve a transmission ratio of -1:3, the base gear wheel preferably comprises
n
B = 32 teeth, the first drive gear wheel comprises n
D1 = 15 teeth, the second drive gear wheel comprises n
D2 = 20 teeth and the spray arm gear wheel comprises ns = 32 teeth. For achieving a
transmission ratio of -1:1, the base gear wheel and the spray arm gear wheel preferably
comprise n
B = ns = 32 teeth. Consequently, their number of teeth does not have to be amended
with regard to the first example. The first drive gear wheel preferably comprises
n
D1 = 12 teeth and the second drive gear wheel comprises n
D2 = 24 teeth. A transmission ratio of 1:5 can be achieved by the same base gear wheel
and the same spray arm gear wheel, while the first drive gear wheel comprises n
D1 = 15 teeth and the second drive gear wheel comprises n
D2 = 12 teeth or the first drive gear wheel comprises n
D1 = 20 teeth and the second drive gear wheel comprises n
D2 = 16 teeth.
[0024] A liquid sprayer as claimed in claim 7 is particularly flexible in use. A pinion
preferably comprises the two drive gear wheels and a drive shaft at which the drive
gear wheels are attached.
[0025] The pinion is preferably attached to a pinion bearing such that it can rotate about
the drive shaft axis, particularly relative to the pinion bearing. The pinion bearing
is preferably reversibly attached to the liquid sprayer, particularly to the drive
arm. For such an attachment, preferably a non-destructive connection, in particular
a snap-in-connection, can be used.
[0026] The drive gear wheels, in particular the pinion can be designed such that their strength
is lower than the strength of the remaining parts of the transmission device. In particular,
the pinion can be designed in the form of a predetermined breaking point, which can
easily be replaced.
[0027] A liquid sprayer as claimed in claim 8 is particularly flexible in use. Since the
number of teeth of the rigidly connected gear wheels are different, an increased drive
torque at the drive arm can be achieved. Further, multiple different transmission
ratios can be set, depending on the ratio of teeth of the two gear wheels.
[0028] A liquid sprayer as claimed in claim 9 is particularly economical in use. The non-circular,
preferably elliptical, more preferably oval shape of the at least one, more preferably
at least two, more preferably at least three, even more preferably at least four,
gear wheels allow for a motion path of the liquid sprayer, particularly its nozzles,
which better fits the shape of the washing chamber, particularly its base shape. Preferably,
interlocking gear pairs have such a shape. The axes of rotation of such wheels can
thus be arranged at a constant distance from each other. Such transmission device
allows for a rectangular, particularly non-square, shape of the motion path of the
at least one spraying nozzle.
[0029] A liquid sprayer as claimed in claim 10 ensures for a proper installation of the
liquid sprayer. As the motion path of the liquid sprayer, particularly its nozzles,
varies over the angle about the base axis, it is particularly important to align the
liquid sprayer, more particularly its motion path, to the base body and thus to the
washing chamber. For achieving such alignment reliably, the liquid sprayer preferably,
comprises alignment means. Such alignment means preferably comprise a form-fitting
means, which reversibly locks the spray arm and/or the drive arm to the base body,
particularly with regard to the rotational movement, particularly in a predefined
alignment. A locked liquid sprayer can be installed into the washing chamber easily,
without the danger of misalignment. The form fitting means preferably comprise a drive
arm through hole, a spray arm through hole and an alignment receiver, which is preferably
rigidly attached to the base body. A detachable alignment means, preferably in the
form of a bolt, can be inserted through the drive arm through hole and the spray arm
through hole into the alignment element receiver, preferably in the direction of the
base axis and/or the spray arm axis and/or the drive shaft axis, such that the drive
arm and the spray arm are locked to the base element. Preferably, there is at least
one, preferably at least two, more preferably at least four, more preferably at least
six, and/or at most two, particularly exactly one, predetermined orientation, to which
the orientation of the drive arm and/or the spray arm is locked by the alignment means.
[0030] A liquid sprayer as claimed in claim 11 is particularly easy and economic to install.
The alignment means preferably comprise the optical means. The optical means can be
designed in the form of an imprint or an embossing to the spray arm, to the drive
arm and/or to the base arm. Such optical means help the assembler or the user to align
the spray arm with the drive arm and/or with the base body. Thus, the orientation
of the motion path of the liquid sprayer perfectly fits with the geometry of the washing
chamber, particularly its base shape.
[0031] A liquid sprayer as claimed in claim 12 to 14 is particularly easy to assemble, economic
in manufacturing and robust in use. Preferably, the drive arm and/or the spray arm
comprise a liquid duct, in particular a hollow structure for conducting the washing
liquid to the nozzles. Preferably, the washing water is conducted into the spray arm
via the drive arm, particularly via its hollow structure. According to an aspect of
the invention, the drive arm comprises a base connector, particularly a base sleeve,
for attaching the drive arm to the base body, particularly to a supply socket that
is attached to the washing chamber. The base connector preferably bears the drive
arm rotatably about the base axis. The base sleeve preferably comprises a drive arm
inflow through which the washing water is conducted into the drive arm. The drive
arm preferably further comprises a spray arm sleeve to which the spray arm is attached
rotatably. The spray arm sleeve determines the spray arm axis. A spray arm connector
of the spray arm preferably comprises a spray arm socket, which can be attached to
the spray arm sleeve of the drive arm. The spray arm socket preferably determines
a spray arm inflow through which the washing water is conducted into the spray arm.
Since the base axis intersects the drive arm inflow and/or the spray arm axis intersects
the spray arm inflow, the washing water can be conducted to the drive arm and/or to
the spray arm, particularly through the drive arm, in a particularly robust manner.
Such liquid sprayer is further economic in manufacturing and easy to assemble.
[0032] A further aspect of the present invention is to provide an enhanced dishwasher, which
is particularly robust as well as time, water and energy saving in use.
[0033] This object is achieved in accordance with the invention by a dishwasher having the
features set out in claim 15. Preferably, the dishwasher is further improved with
at least one feature disclosed with reference to the liquid sprayer described above.
The base body can be a part of the dishwasher, particularly of its washing chamber
and/or its sump. Alternatively, the base body can be designed as part of the liquid
sprayer, which is reversibly attachable to the dishwasher, particularly to the washing
chamber and/or the sump. Therefore, the dishwasher preferably comprises an attachment
means, to which the base body can be mounted, particularly in a rotationally fixed
manner, particularly about the base axis. Such attachment means is preferably the
supply socket for supplying the washing water to the liquid sprayer.
[0034] The dishwasher preferably comprises at least one dish basket, preferably two dish
baskets. The dishwasher preferably comprises at least one, more preferably at least
two, of the liquid sprayers. The at least one liquid sprayer is preferably located
below the at least one dish basket, particularly at the bottom of the washing chamber
and/or below an upper one of the dish baskets.
[0035] The base shape of the washing chamber is, according to an aspect of the invention,
polygonal, particularly rectangular, particularly square or non-square. The base shape
of the washing chamber preferably is designed with an aspect ratio of almost 1:1 or
at least 6:5, preferably at least 5:4, , more preferably at least 4:3, more preferably
at least 3:2, more preferably at least 2:1. The base shape of the washing chamber
is specified by its outline in a top view. Edge and corner areas of the washing chamber
are preferably neglected. In practice, they can be rounded off. The liquid sprayer
described above allows for a particularly uniform distribution of washing water in
a polygonal washing chamber.
[0036] Further features, advantages and details of the invention result from the subsequent
description of exemplary embodiments. In the drawings:
- Fig. 1
- shows a schematic front view of a dishwasher according to a first embodiment, comprising
a washing chamber, a sump and at least one liquid sprayer,
- Fig. 2
- shows a perspective view of the liquid sprayer in fig. 1 from above the liquid sprayer,
wherein the liquid sprayer comprising a drive arm, a spray arm and a transmission
device,
- Fig. 3
- shows a perspective view of the liquid sprayer in fig. 1 from below the liquid sprayer,
- Fig. 4
- shows a top view of the liquid sprayer in fig. 1,
- Fig. 5
- shows an exploded view of the liquid sprayer in fig. 1,
- Fig. 6
- shows a perspective view of the liquid sprayer in fig. 1 from above the liquid sprayer,
wherein the drive arm and the spray arm are rigidly locked to a base body by means
of an assembly aid,
- Fig. 7
- shows a perspective sectional view along the section line VII-VII in fig. 6,
- Fig. 8
- shows a side view of the liquid sprayer in fig. 1,
- Fig. 9
- shows a sectional view along the section line IX-IX in fig. 6,
- Fig. 10
- shows a detailed view of the transmission device of the liquid sprayer in fig. 1,
- Fig. 11
- shows a perspective view of a gear wheel module of the liquid sprayer in fig. 1,
- Fig. 12
- shows a motion path of an outermost spraying nozzle of the spray arm of the liquid
sprayer in fig. 1,
- Fig. 13
- shows a perspective view of a gear wheel module for the liquid sprayer in fig. 1 according
to another embodiment,
- Fig. 14
- shows a motion path of a spraying nozzle of the outermost spraying nozzle of the spray
arm of the liquid sprayer in fig. 1 with the gear wheel module in fig. 13, and
- Fig. 15
- shows an exploded view of a liquid sprayer according to another embodiment, comprising
a drive arm, a spray arm and a transmission device with a base gear wheel that can
reversibly be attached to a sump of the dishwasher.
[0037] A dishwasher 1 according to a first embodiment as shown in fig. 1 to fig. 12 comprises
a washing chamber 2, a sump 3 that is arranged at the bottom of the washing chamber
2 and a liquid sprayer 4 for dispensing liquid within the washing chamber 2. In the
washing chamber 2 two dish baskets 5a, 5b for carrying dishes 6 are arranged. The
liquid sprayer 4 is located below the lower dish basket 5a. A second liquid sprayer
7 is located below the upper dish basket 5b.
[0038] The dishwasher 1 further comprises a fluid management device 8 for providing the
liquid sprayers 4, 7 with washing liquid, particularly washing water. The fluid management
device 8 comprises at least one liquid pump for conveying the washing liquid and/or
at least one valve for controlling the flow of the washing liquid. These are not shown
in the figures.
[0039] The washing chamber 2, the sump 3, the liquid sprayers 4, 7, the dish baskets 5a,
5b and the fluid management device 8 are located within a dishwasher housing 9. The
dishwasher 1 comprises a fresh water port 10, through which fresh water is provided,
and a drain water port 11, through which drain water is discharged. The fresh water
port 10 and the drain water port 11 are connected to the fluid management device 8
via water ducts 12.
[0040] In fig. 2 to fig. 12, the liquid sprayer 4 in fig. 1 is shown in more detail. The
liquid sprayer 4 is attached to a base body 13. The base body 13 comprises a drain
grid 14 for filtering large objects from the washing water to avoid them entering
into the sump 2. The base body 13 further comprises a supply socket 15. The drain
grid 14 and the supply socket 15 are one piece.
[0041] The liquid sprayer 4 comprises a drive arm 16 and a spray arm 17. The drive arm 16
is mounted to the base body 13 so that it can rotate about a base axis 18. The spray
arm 17 is mounted to the drive arm 16 so that it can rotate about a spray arm axis
19.
[0042] The base axis 18 is determined by means of a base connector 20, which is part of
the drive arm 16 and arranged for reversibly attaching the drive arm 16 to the base
body 13. The base connector 20 is designed such that the drive arm 16 can freely rotate
about the base axis 18 and such that washing water can be conducted liquid-tight between
the supply socket 15 and the drive arm 16. Therefore, the base connector 20 comprises
a base sleeve 21, which can be inserted in the supply socket 15. Two bearing rings
22 are attached to the base sleeve 21 and provide the rotatable bearing and the waterproof
connection.
[0043] The spray arm 17 comprises a spray arm connector 23 that is designed to connect the
spray arm 17 to the drive arm 16 so that they can rotate relative to each other about
the spray arm axis 19. The drive arm 16 comprises a spray arm sleeve 24, which can
be plugged into a spray arm socket 25 of the spray arm connector 23. For providing
the rotatable bearing and a watertight connection between the spray arm 17 and the
drive arm 16, the spray arm sleeve 24 comprises two bearing rings 26.
[0044] The drive arm 16 and the spray arm 17 comprise a hollow structure 27, 28. The hollow
structure 27 of the drive arm 16 provides a fluid conducting connection between the
base sleeve 21 and the spray arm sleeve 24. Via the spray arm socket 25, the fluid
is conducted from the hollow structure 27 of the drive arm 16 into the hollow structure
28 of the spray arm 17. Thus, washing water, which is supplied via the supply socket
15, is conducted via the drive arm 16 into the spray arm 17.
[0045] The drive arm 16 comprises two nozzles 29, in particular drive nozzles 29. The drive
nozzles 29 are designed such that washing water sprayed out via the drive nozzles
29 causes a drive force F
D, which leads to a drive torque M
D about the base axis 18. Consequently, spraying out water via the drive nozzle 29
sets the drive arm 16 into rotation about the base axis 18.
[0046] The spray arm 17 comprises at least one, in particular multiple, spraying nozzles
30, 30a. The spraying nozzles 30, 30a are preferably aligned to spray out the washing
water in a direction that is parallel to the base axis 18 and/or the spray arm axis
19, particularly in the vertical direction. Since the liquid sprayer is arranged below
the dish basket 5a, the dishes 6 within this dish basket 5a can be cleaned efficiently
and reliably by means of the liquid sprayer 4.
[0047] The spraying nozzle 30, 30a which is most distant from the spray arm axis 19, has
the reference sign 30a. The spray arm 17 is eccentrically attached to the drive arm
16. The drive arm 16 has two spray booms 17a, 17b, a larger one 17a and a shorter
one 17b. The dimension rL of the larger spray boom 17a of the spray arm 17 perpendicular
to the spray arm axis 19 is 240 mm. The dimension rs of the smaller spray boom 17b
of the spray arm 17 perpendicular to the spray arm axis 19 is 160 mm.
[0048] In particular, the drive nozzles 29 is in fluid conducting connection with the hollow
structure 27 of the drive arm 16. The spraying nozzles 30, 30a are in fluid conducting
connection with the hollow structure 28 of the spray arm 17. Both types of nozzles
29, 30, 30a are supplied with washing water via the base sleeve 21, particularly via
the supply socket 15.
[0049] The liquid sprayer 4 comprises a transmission device 31, which couples the rotational
movement of the drive arm 16 about the base axis 18 with the rotational movement of
the spray arm 17 about the spray arm axis 19. The transmission device 31 is designed
in the form of a gear transmission. The transmission device 31 comprises four gear
wheels 32, 33, 34, 35. A base gear wheel 32 is rigidly connected to the supply socket
15. The base gear wheel 32 is part of the base body 13. The base gear wheel 32 interlocks
with a first drive gear wheel 33 that is rotatably attached to the drive arm 16. A
second drive gear wheel 34 is also attached to the drive arm 17 rotatably. In particular,
the first drive gear wheel 33 and the second drive gear wheel 34 are rigidly connected
to each other via a drive shaft 36. The drive shaft 36 is attached to the drive arm
26 such that it can rotate about a drive shaft axis 37. The second drive gear wheel
34 interlocks with a spray arm gear wheel 35 that is rigidly attached to the spray
arm 17. In particular, the base gear wheel 32 and the supply socket 15 are formed
in one piece. The spray arm gear wheel 35 and the spray arm 17 are also formed in
one piece. The drive gear wheels 33, 34 and the drive shaft 36 can be formed in one
piece. The part comprising the drive gear wheels 33, 34 and the drive shaft 36 is
referred to as a pinion 38.
[0050] The base gear wheel 32 is rigidly connected to the washing chamber 2, in particular
also to the sump 3 and to the dishwasher housing 9. The transmission device 31 transforms
the rotational motion of the drive arm 16 into a rotation of the pinion 38 with the
two drive gear wheels 33, 34. The rotation of the second drive gear wheel 34 causes
a rotation of the spray arm gear wheel 35 and thus of the spray arm 17 about the spray
arm axis 19. A drive arm rotation rate ω
D is the rotation rate of the drive arm 16 in a stationary coordinate system 39, in
particular about a vertical axis, particularly the base axis 18. A spray arm rotation
rate ω
S is a rotation rate of the spray arm 17 in the stationary coordinate system 39, in
particular about the vertical axis, particularly the spray arm axis 19 or the base
axis 18. The transmission device 31 is configured such that a transmission ratio γ
between the spray arm rotation rate ω
S and the drive arm rotation rate ω
D is -1:3.
[0051] In order to accomplish such transmission ratio γ, the base gear wheel 32 comprises
n
B = 32 teeth, the first drive gear wheel 33 comprises n
D1 = 15 teeth, the second drive gear wheel 34 comprises n
D2 = 20 teeth and the spray arm gear wheel 35 comprises ns = 32 teeth. All of the gear
wheels 32, 33, 34, 35 are arranged outside the fluid duct within the drive arm 16,
particularly outside the hollow structure 27 of the drive arm 16. These gear wheels
32, 33, 34, 35 are also located outside the spray arm 17, particularly outside the
hollow structure of the spray arm 17. Thus, they are particularly easy to clean and
less space consuming.
[0052] The base axis 18, the spray arm axis 19 and the drive shaft axis 37 are aligned parallel
and spaced apart from each other.
[0053] The base sleeve 21 determines a drive arm inflow 40 for receiving the washing water.
The spray arm sleeve 24 has a drive arm outflow 41 through which the washing water
is transferred to the spray arm 17. The spray arm socket 25 determines a spray arm
inflow 42 through which the washing water is received. The base axis 18 intersects
the drive arm inflow 40. The supply socket 15 and/or the base sleeve 21 is at least
in sections rotationally symmetrical to the base axis 18. The spray arm axis 19 preferably
intersects the drive arm outflow 41 and/or the spray arm inflow 42. The spray arm
sleeve 24 and/or the spray arm socket 25 are preferably at least in sections rotationally
symmetrical to the spray arm axis 19. The water duct 12 within the liquid sprayer
4, in particular in the drive arm 16 and/or in the spray arm 17, is intersected by
the base axis 18 and/or the spray arm axis 19.
[0054] The pinion 38 is mounted to a pinion bearing 43. The pinion bearing 43 and the pinion
38 determine a reversibly detachable gear unit 44a. The gear unit 44a can be mounted
to the drive arm 16 by means of a detachable connection 45, in particular a snap-fit-connection.
In particular, the gear unit 44a is replaceable with alternative gear units 44b, which
comprise drive gear wheels 33, 34 with a different number of teeth n
B, n
D1, n
D2, n
S. Thereby, the transmission ratio γ of the transmission device 31 can easily be amended.
[0055] The detachable connection 45 is designed such that the drive shaft axis 37 of different
gear units 44a can be located differently with reference to the position of the base
axis 18 and/or the spray arm axis 19. Thus, the distance between the drive shaft axis
37 and the base axis 18 or the spray arm axis 19 can be adjusted to the particular
number of teeth n
D1, n
D2 of the drive gear wheels 33, 34, in particular without amending the design, particularly
the number of teeth n
B, ns of the base gear wheel 32 or the spray arm gear wheel 35.
[0056] The liquid sprayer 4 comprises alignment means 46 for aligning the drive arm 16 with
the spray arm 17 and the base body 13 in a specific orientation to each other. Such
alignment means 46 comprise a drive arm through hole 47, a spray arm through hole
48 and at least one alignment element receiver 49 in the form of a through hole within
the base body 13. The drive arm through hole 47, the spray arm through hole 48 and
the alignment element receiver 49 are designed such that an alignment element 50,
preferably in the form of a bolt can be pushed through all of these holes 47, 48,
49 in order to lock the orientation of the drive arm 16 and the spray arm 17 relative
to the base body 13 in a predefined alignment. Such form-fitting means allow for a
correct installation of the liquid sprayer 4 with regard to the base body 13 and the
washing chamber 2 in a particularly reliable manner.
[0057] The alignment means 46 comprise optical means not shown that indicate the correct
orientation of the drive arm 16, the spray arm 17 and the base body 13 within the
washing chamber 2. Such optical means preferably comprise signs, such as arrows, which
point at each other or at a specific target, when the liquid sprayer 4 is properly
aligned.
[0058] The functionality of the dishwasher 1, in particular the liquid sprayer 4, is as
follows:
In an initial state, the dishwasher 1 is deactivated. The dishes 6 are deposited in
the dish baskets 5a, 5b.
[0059] The user selects a washing program and activates the dishwasher 1. By means of the
fluid management device 8, fresh water is conveyed into the washing chamber 2. The
water is heated by means of the fluid management device 8 and repeatedly circulated
from the sump 3 to the washing chamber 2.
[0060] The washing water is conducted into the washing chamber 2 by means of the liquid
sprayers 4, 7, which spread the washing water within the washing chamber 2. The washing
water is conducted from the fluid management device 8 via the water duct 12 to the
supply socket 15 and via the drive arm inflow 40 into the hollow structure 27 of the
drive arm 16. Via the spray arm sleeve 24 and the spray arm inflow 42, the washing
water is further conducted into the hollow structure 28 of the spray arm 17. The washing
water is ejected through the nozzles 29 and 30, 30a.
[0061] In fig. 12, the motion of the nozzle 30a, which is most distant to the spray arm
axis 19, is shown. The motion path of this nozzle 30a has the reference sign 51a.
The washing chamber 2 has a square base area, except for its edges. It can be seen
from fig. 12 that the motion path 51a of the nozzle 38 fits perfectly to the square
base. Washing water can be spread in the edge regions of the washing chamber 2, while
a collision between the liquid sprayer 4 and the washing chamber walls is reliably
avoided. Due to the distance between the base axis 18 and the spray arm axis 19 as
well as the eccentric attachment of the spray arm 17 to the drive arm 16, a motion
pattern of the spray arm 17 can be achieved, which allows for a particularly uniform
distribution of water within the washing chamber 2 and over the dishes 6.
[0062] Due to the transmission ratio γ, which is -1:3, the spray arm 17 and the drive arm
16 rotate in opposite directions with respect to the stationary coordinate system
39. This means that the drive arm 16 rotates three times about the base axis 18 while
the spray arm 17 rotates one time in the opposite direction, in particular about the
spray arm axis 19 or the base axis 18. Thus, the nozzle 30a reaches one of the four
edges of the washing chamber 2 every 270 degrees of rotation of the drive arm 16 respectively
every 90 degrees of rotation of the spray arm 17.
[0063] The liquid sprayer 4, in particular the drive arm 16 and the spray arm 17, is driven
by the drive force F
D which results from ejecting washing water through the drive nozzles 29. Due to the
fact that the transmission ratio γ is in absolute value less than 1, the drive arm
16 rotates faster than the spray arm 17. In other words, the drive arm rotation rate
ω
D is in absolute value larger than the spray arm rotation rate ω
S. The drive torque M
D that is thereby applied to the drive arm 16 is multiplied by the transmission device
31 by the factor of the transmission ratio γ. A spray arm torque Ms that drives the
spray 17 in rotation about the spray arm axis 19 is thus three times as high as the
drive torque M
D. The liquid sprayer 4 is thus set in rotation in a particularly reliable manner.
The dishes 6 are cleaned in a particularly reliable, time saving and energy efficient
manner, due to the fact that the washing water is dispensed evenly and that the rotation
of the spray arm is robust against dirt deposit and calcification.
[0064] To ensure the correct alignment of the motion path 51a that is shown in fig. 12 with
respect to the washing chamber 2, particularly about the base axis, it is particularly
important that the transmission device 31 is aligned properly. Such an adjustment
is helpful during the assembly of the dishwasher 1 or the reinstallation of the liquid
sprayer 4 after maintenance, in particular after cleaning. For easily achieving such
correct alignment, the gear unit 44a is detached from the drive 16. The drive arm
16 and the spray arm 17 are aligned such that the drive arm through hole 47, the spray
arm through hole 48 and the alignment element receiver 49 overlap each other. The
alignment element 40 can then be inserted through the through holes 47, 48 into the
alignment receiver 49. In this position, the gear unit 44a can be attached to the
drive arm 16 by just pushing it into the according gear unit reception 52. The gear
unit 44a is secured to the drive arm 16 by means of the snap-fit-connection. Thereby,
the drive arm 16 and the spray arm 17 are aligned properly with respect to the base
body 32 and the washing chamber 2.
[0065] The alignment element 50 has to be removed from the liquid sprayer 4 to unlock the
rotation of the drive arm 16 and the spray arm 17 about the base axis 18 and the spray
arm axis 19. The liquid sprayer 4 is properly aligned to the washing chamber 2 and
the dishwasher 1 is ready for the next washing process.
[0066] Fig. 13 shows a gear unit 44b that can be used with the liquid sprayer 4 as an alternative
to the gear unit 44a in fig. 11. The use of this gear unit 44b results in the motion
path 51b of the spraying nozzle 30a shown in fig. 14. Such motion path 51b has an
elliptical, in particular an oval shape. Such an elliptically shaped motion path 51b
is particularly advantageous for the use with a washing chamber 2 with a rectangular,
non-square base shape.
[0067] Due to the fact that the gear unit 44a, 44b is reversibly attachable to the drive
arm 16, the liquid sprayer 4 can easily be adapted to dishwashers 1 with different
washing chambers 2, in particular with different base shapes. Particularly, the same
drive arm 16 and spray arm 17 can be used for dishwashers 1 with different geometries
while only the gear unit 44a, 44b has to be designed or selected accordingly. The
manufacturing costs of the dishwasher 1 can thus be considerably reduced.
[0068] Fig. 15 shows another embodiment of a liquid sprayer 4 according to the invention.
In contrast to the aforementioned embodiment, the drive arm 16 comprises two drive
nuzzles 29, which are aligned in a plane perpendicular to the base axis 18.
[0069] The pinion bearing 43 and the drive arm 16 are one piece. The pinion 38 is thus not
detachable from the drive arm 16.
[0070] The base gear wheel 32 and the supply socket 15 are separate parts, which can be
attached to each other by means of a snap-fit-connection. Thus, the dishwasher 1 can
flexibly be equipped with either a conventional liquid sprayer 4 without a transmission
device 31, particularly a base gear wheel 32, or with a liquid sprayer 4 according
to the above described invention.
[0071] The functionality of the liquid sprayer 4 in fig. 15 corresponds to the functionality
of the aforementioned liquid sprayer 4.
[0072] The gear wheels 32, 33, 34, 35 of the aforementioned embodiments have a circular
shape. According to another embodiment, which is not shown in the figures, at least
two interlocking gear wheels comprise a non-circular gear rim, in particular with
an elliptical shape, more particular an oval shape. Thereby, a motion path 51a, 51b
can be achieved which even better fits to the base shape of the washing chamber 2.
In particular, a more even distribution of washing water within a rectangular, particularly
a non-square, washing chamber 2 can be achieved.
[0073] The dishwasher 1 with the liquid sprayer 4 according to the invention can be used
particularly flexible with differently shaped washing chambers 2. It allows for a
cost saving manufacturing of the dishwasher. Further, a more uniform distribution
of washing water within the washing chamber 2 can be achieved. The dishwasher 1 is
particularly time, water and energy saving and durable.
1. Liquid sprayer (4) for a dishwasher (1), comprising
1.1. a drive arm (16), with a base connector (20) for attaching the drive arm (16)
to a base body (13) so that it can rotate about a base axis (18),
1.2. a spray arm (17), with
1.2.1. a spray arm connector (23) that attaches the spray arm (17) to the drive arm
(16) so that it can rotate about a spray arm axis (19), wherein the spray arm axis
(19) is spaced apart from the base axis (18), and
1.2.2. at least one spraying nozzle (30, 30a) for dispensing washing liquid, and
1.3. a transmission device (31) which couples a rotational movement of the drive arm
(16) about the base axis (18) to a rotational movement of the spray arm (17) about
the spray arm axis (19),
characterized
1.4. in that the drive arm (16) comprises at least one drive nozzle (29) for driving
the drive arm (16) in rotation about the base axis (18), and
1.5. in that the transmission device (31) couples the rotational movements of the drive arm (16)
and the spray arm (17) such that a drive arm rotation rate (ωD) is in absolute values at least as large as a spray arm rotation rate (ωs).
2. Liquid sprayer (4) according to claim 1, characterized in that the transmission device (31) couples the rotational movements of the drive arm (16)
and the spray arm (17) such that the drive arm rotation rate (ωD) is greater in absolute values than the spray arm rotation rate (ωS).
3. Liquid sprayer (4) according to claim 1 or 2, characterized in that the transmission device (31) is configured such that in a stationary coordinate system
(39) the drive arm (16) and the spray arm (17) move in opposite directions.
4. Liquid sprayer (4) according to any of the preceding claims, characterized in that the transmission device (31) comprises at least three interlocking gear wheels (32,
33, 34, 35) for coupling the rotational movement of the drive arm (16) to the rotational
movement of the spray arm (17).
5. Liquid sprayer (4) according to any of the preceding claims, characterized in that the transmission device (31) comprises at least one gear wheel (32, 33, 34, 35) that
is located outside a liquid duct (12) for conducting the washing liquid.
6. Liquid sprayer (4) according to any of the preceding claims, characterized in that the transmission device (31) comprises at least four interlocking gear wheels (32,
33, 34, 35) for coupling the rotational movement of the drive arm (16) to the rotational
movement of the spray arm (17), wherein two of the gear wheels (33, 34) are rigidly
connected to each other.
7. Liquid sprayer (4) according to claim 6, characterized in that the two rigidly connected gear wheels (33, 34) are reversibly attached to the liquid
sprayer (4).
8. Liquid sprayer (4) according to claim 6 or 7, characterized in that the two rigidly connected gear wheels (33, 34) have different numbers of teeth.
9. Liquid sprayer (4) according to any of the preceding claims, characterized in that at least two of the gear wheels (32, 33, 34, 35) have a non-circular gear rim.
10. Liquid sprayer (4) according to any of the preceding claims, characterized in that the drive arm (16) and/or the spray arm (17) comprises a form-fitting means (47,
48) for limiting the orientation possible for attaching the drive arm (16) to the
base body (13) to at least one predetermined orientation.
11. Liquid sprayer (4) according to any of the preceding claims, characterized in that the drive arm (16) and/or the spray arm (17) comprise optical means for indicating
their intended installation orientation.
12. Liquid sprayer (4) according to any of the preceding claims, characterized in that the drive arm (16) comprises a liquid duct (12) for conducting the washing liquid
from a drive arm inflow (40) to a spray arm inflow (42) of the spray arm (17).
13. Liquid sprayer (4) according to claim 12, characterized in that the base axis (18) intersects the drive arm inflow (40).
14. Liquid sprayer (4) according to claim 12 or 13, characterized in that the spray arm axis (19) intersects the spray arm inflow (42).
15. Dishwasher (1) for cleaning dishes (6), comprising
15.1. a washing chamber (2) for receiving the dishes (6), and
15.2. at least one liquid sprayer (4) according to any of the preceding claims.