Household mixing appliance

The mixing appliance comprises a housing (2) with an electromotor (4), two spindles (9) each adapted to receive a mixing implement (11) in such a way that it is secured against turning but releasable, and a drive connection (7, 8) between the electromotor (4) and the spindles (9), the two spindles (9) and their drive connections (7, 8) being designed such that beaters (11) secured in these spindles (9) during operation are mutually counterrotating and provide between them a flow direction, and such that the areas touched by such beaters during operation overlap each other. The appliance comprises at least one additional spindle (15) for simultaneous, releasable receipt of an additional mixing implement (16) of the same type as the abovementioned mixing implements (11) and a further drive connection (17, 18, 20) for driving a mixing implement (16) in a further spindle (15). The two abovementioned spindles (9) are positioned in two neighbouring corners of a rectangle, within which the additional spindle(s) (15) is/are placed.

The present invention relates to a household mixing appliance, such as a 
manually operated mixer, comprising a housing with an electromotor, two 
spindles each adapted to receive a mixing implement in such a way that it 
is secured against turning but releasable, and a drive connection between 
the electromotor and the spindles, the two spindles and their drive 
connections being designed such that beaters secured in these spindles 
during operation are mutually counter rotating and provide between them a 
flow direction, and such that the areas touched by such beaters during 
operation overlap each other. 
Household mixing appliances of this type have been known for years and 
comprise exactly two spindles which are adapted to receive either a pair 
of dough hooks for mixing a dough or a pair of beaters for whipping for 
instance whipping cream or egg whites. 
Household mixing appliances with three spindles in line is known from U.S. 
Pat. No. 2,275,878 which relates to a mixer with illumination means, and 
from FR-B-1 043 011 and FR-B-1 068 640 which both relate to an ejection 
means for the mixing implements in a mixer. 
In U.S. Pat. No. 2,275,878 FIG. 1 shows the three mixing implements placed 
in such a way in a mixing bowl that the "foremost" one is positioned at 
the center of the bowl, whereas the "rear" one is positioned at the edge 
of the bowl. The three mixing implements in line thus seem to be arranged 
to ensure mixing of all the material in a big bowl. FR-B-1 043 011 and 
FR-B-1 068 640 merely show three mixing implements arranged in line. 
U.S. Pat. No. 4,176,971 discloses a household mixing appliance with four 
spindles, two of which are rotating slowly and adapted to receive dough 
hooks, whereas the two other ones are adapted to receive beaters. The 
spindles are designed such that they can only receive their matching 
mixing implements (beaters or dough hooks). Furthermore, an ejection means 
for the mixing implements is designed in such a way that it becomes 
impossible to mount beaters and dough hooks simultaneously. 
Likewise, GB-A-2 241 653 discloses a household mixing machine with four 
spindles. This machine is a further development of the one described in 
the above mentioned U.S. Pat. No. 4,176,971, and it is also here intended 
to use one pair of mixing implements at a time. A part of the development 
consists in an amended device for retaining the mixing implements, said 
device comprising a slidably movable plate with locking areas engaging 
recesses in the shafts of the mixing implements. The plate is spring-urged 
into a locking position by means of two spring legs and it is rotatable to 
a limited extent, whereby one mixing implement of a pair may be inserted, 
and the second mixing implement of the pair may be inserted without 
thereby releasing the implement first inserted. The possibility of 
inserting a third or a fourth mixing implement without releasing the 
previously inserted ones is not mentioned and does not seem to exist. 
DE-A-40 33 020 discloses a mixing bowl provided with a mixing mechanism 
which is pivotally journalled on a central elevation in the bowl and 
comprises several spindles driven with separate gear and designed to 
receive different mixing implements. The mixing mechanism has at the top a 
central inlet shaft for connection with the spindle of a hand mixer. The 
mixing mechanism has three spindles, which are, however, not used 
simultaneously. 
The object of the present invention is to provide a household mixing 
appliance of the type mentioned by way of introduction, which appliance 
gives a more effective mixing or beating than the prior art appliances. 
By the term "mixing implements of the same type" is here to be understood 
for instance beaters or dough hooks which are not necessarily identical in 
respect of design but which are intended for the same kind of work, for 
instance beating, mixing or kneading. 
In a preferred embodiment the additional drive connection comprises a 
teething on one of the first mentioned mixing implements and a gear 
journalled in the housing and engaging a teething on the additional 
spindle or the additional mixing implement, when the mixing implements are 
mounted in the respective spindles. Owing to this the additional spindle 
cannot operate when mixing implements which are only intended to work in 
pairs are used and which therefore will not be provided with the first 
mentioned teething. 
In a further preferred embodiment one additional spindle is placed such 
that the three spindles constitute corners in an isosceles triangle, 
whereby the area touched by a beater mounted in the additional spindle 
does not overlap the areas touched by the first mentioned beaters, and the 
additional spindle is preferably placed downstream relative to said flow 
direction. With this embodiment a reduction of time consumption of approx. 
40% when beating egg whites has been ascertained.

The hand mixer 1 shown in FIGS. 1-3 comprises in a conventional way a 
housing 2 which has a handle 3 and which holds an electromotor 4 with a 
through shaft 5 which at one end carries an impeller 6 and at its other 
end a worm 7 which is in engagement with two gears 8, of which only one is 
to be seen in FIG. 3, as the second one is positioned behind the first 
one. The gears 8 are fixedly journalled on each their spindle 9 which is 
intended, in a way secured against turning, to receive the shaft 10 of a 
mixing implement which in the example shown is a beater 11. As will be 
seen from FIG. 2 two such beaters 11 are placed side by side, whereby the 
areas which are touched by them when they rotate overlap. 
The mixing appliance 1 furthermore comprises an ejector 12 for the mixing 
implements, a speed control with a control knob 13 as well as a switch 14. 
As described up till now the mixing appliance 1 is quite conventional. 
However, it comprises an additional spindle 15 which is positioned in such 
a way that it constitutes the apex in an isosceles triangle formed by the 
three spindles 9, 15. The additional spindle 15 is placed so far from the 
two other spindles 9 that a beater 16 mounted therein does not when 
rotating overlap the areas touched during operation by the two previously 
mentioned beaters 11, whereby collision is prevented. 
The spindle 15 is driven through one of the first mentioned beaters 11, 
which on its shaft 10 carries a teething 17 which, when this beater 11 is 
mounted, is in engagement with a gear 18 journalled on a pin 19 in the 
housing 2, said gear 18 being furthermore in engagement with a teething 20 
on the spindle 15. 
In the case shown the teethings 17 and 20 have the same amount of teeth, 
for which reason the beater 16 will rotate with the same speed as the 
beaters 11. This is, however, no prerequisite which has to be met. 
In spite of the fact that a gear transmission has been described above the 
invention is not confined thereto. Several other possibilities will be 
obvious for the one skilled in the art, for instance belt drive, friction 
wheels instead of gears, drive pinions, etc. 
Tests with a hand mixer of the type described above has shown than when 
beating egg whites a reduction of approx. 40% of the time consumption 
relative to beating with only two beaters 11 is obtained, whereas when 
beating whipped cream a slightly smaller reduction of the time consumption 
is obtained. The configuration shown of the three beaters 11, 16 has the 
advantage, that the mixing bowl does not have to be significantly bigger 
than in case of two beaters, the increase of the space demand only being 
16% in diameter. 
Even though the use of three beaters has been described above, the 
invention is not confined thereto. Also four beaters might be used, and 
FIGS. 4a-4d show different ways of configurating four whiskers, the 
figures showing the areas touched by the individual beaters and the 
direction of rotation of the beaters. In FIG. 4a the outline of the 
housing 2 has been indicated by a dotted line and it is to be understood 
that the housing in the other shown configurations will be positioned in 
the same way relative to the beaters. 
FIG. 4a shows four beaters 11, 16, the areas touched by them during 
operation overlapping in each case two neighboring areas, whereby material 
which is being beaten will be pulled in at the sides between two beaters 
11, 16 to be sent either forwards or backwards between two beaters 11 and 
16 as indicated by arrows. 
FIGS. 4b-4d show different possible rotational directions in a 
configuration, where four beaters are pairwise mutually overlapping. It 
should be noted that in all the examples shown, the two beaters 11 
correspond to the two beaters in a conventional hand mixer, whereas the 
beaters indicated by 16 are those added according to the invention. 
In a variant of the configuration shown in FIG. 2 of the positioning of the 
mixing implements or the beaters, the beater 16 is laterally displaced, 
for instance to the right seen in FIG. 2. In such an asymmetric 
configuration the beater 16 may either rotate clockwise or anticlockwise 
and may then act as a feeder, if the beaters 11 rotate such that they pull 
in material from the side, in which the beater 16 is present, or it may 
act receiver, if the beaters 11 rotate such that they eject material to 
the side, in which the beater 16 is present, and the beater 16 rotates 
clockwise as seen in FIG. 2.