[0001] This invention relates to food mixers and more particularly to guards for preventing
the operator of such mixers from entering the mixing zone thereof, especially when
the mixer is in use.
[0002] Food mixers normally comprise a motor to which various mixing implements, for example
whisks, beaters, blades and so on, may be attached. The mixing implement extends into
a bowl which is attached to and removable from the mixer. Such mixers may be used
for catering or other industrial mixing purposes and will hereafter be referred to
as a "mixer of the type described".
[0003] When these mixers are used in the work place, safety is obviously a major concern.
It is therefore desirable to provide means which prevent an operator coming into contact
with the mixing implement, especially when the mixing implement is rotating.
[0004] Often a guard is used which fits around the top of the bowl. The guard may be solid
or comprise a number of bars, spaced apart at such a distance that a hand may not
be inserted between them. The guard is pivotally connected to the mixer so that access
to the bowl is permitted by swinging the guard upwardly or outwardly. In order to
increase the safety of the mixer the guard is usually so arranged that, when it is
swung away from the edge of the bowl, the motor is stopped to prevent rotation of
the mixing implement. However such a swinging movement of the guard takes up valuable
space within the kitchen.
[0005] A food mixer in accordance with the invention comprises a body, a bowl releasably
mounted on the bowl, a motor for moving a food processing implement within the bowl
and a guard assembly above the bowl comprising two parts, complementary in shape,
one of which is rotatable between at least two positions, a first closed position
in which it prevents access to the bowl and a second open position about or within
the second part, which second part is mounted in a fixed position relative to the
bowl.
[0006] The rotatable part of the guard assembly when open, remains within the profile of
the fixed part of the guard assembly which therefore does not require extra clearance
when opened.
[0007] Preferably the rotatable and fixed parts of the guard assembly are both partially
hemispherical in shape. The guard assembly preferably has a portion formed with bars
to allow an operator to see into the bowl and to add further ingredients whilst the
mixing implement rotates.
[0008] The rotatable part of the guard assembly is preferably secured to the fixed part
by means of a ring, or other fixing device.
[0009] The mixer preferably includes means for sensing movement of the rotatable part of
the guard assembly relative the body operatively connected to or integral with means
for preventing energisation of the motor when the rotatable part is not in the closed
position. This means preferably comprises a switch and an activator provided respectively
on the body of the mixer and the rotatable part of the guard assembly. The switch
and the activator are preferably arranged to be directly opposite each other when
the guard assembly is completely closed. When the activator moves relative to the
switch, owing to movement of the rotatable part of the guard assembly, the switch
will trip and prevent motor energisation. The switch is sensitive to the proximity
of the activator and will therefore detect a relatively small movement of the rotatable
part of the guard assembly. This arrangement ensures that the motor cannot be energised
when the guard assembly is open or it has been removed for cleaning.
[0010] The rotatable part of the guard assembly is preferably not locked in place but rather
is free to move at all times, so that should an object be inserted into the bowl and
be caught by the mixing implement, any resulting slight movement imparted to the rotatable
part of the guard will cause the switch to disconnect power to the motor. Preferably
means are also provided between the bowl and the body of the mixer to deactivate the
motor when the bowl is not properly set in its working position.
[0011] The invention will now be further described by way of example with reference to the
accompanying drawings in which:-
Figure 1 is a side view of a food mixer in accordance with the invention.
Figure 2 is a plan view of the guard assembly of the mixer of Figure 1.
Figure 3 is a section (on an enlarged scale) on the line A-A of Figure 2.
Figure 4 is a section on the line B-B of Figure 2.
[0012] As shown in Figure 1, a food mixer 2 has a bowl 4 into which extends a mixing implement
6. The upper end of the mixing implement engages with a bearing which is driven by
a motor (not shown). The bowl 4 is supported by arms 8 and may be removed by lowering
the arms and then lifting the bowl, to disengage an engaging means 10 which co-operates
with brackets 12 provided on the side of the bowl.
[0013] A guard assembly 14 is provided around the top of the bowl 4 to prevent access to
the bowl. The rear half 16 of the guard assembly is fixed relative to the front half
18, which in the embodiment illustrated is in the form of a 'cage' comprising a number
of horizontal bars 20 spaced and supported by upright bars 22. This arrangement allows
the operator to see into the bowl and to add further ingredients during mixing whilst
preventing access to the mixing zone.
[0014] As can be seen from Figures 2 and 3 the fixed part 16 of the guard assembly is attached
to a central housing 24 which may house gearing. The outer perimeter of the housing
is provided with a fixing device 26 by which the fixed part 16 of the guard assembly
is mounted to the body of the mixer 2. A semi-circular gutter 28 is provided on the
bottom edge of housing 24 in order to catch any fluid or the like which may fall from
the housing. The front half 18 of the guard assembly 14 is carried on a retaining
ring 30 by means of the upright bars 22. The retaining ring 30 is mounted in a slidable
manner on the fixing device 26 of the housing 24, so allowing the front half 18 to
rotate about the central axis X-X of the guard assembly and over the fixed part 16,
to an open position in which the interior of the bowl 4 is accessible.
[0015] No clearance around the mixer is required since the profile of the guard assembly
14 remains substantially the same, whether the rotatable part 18 is in the closed
or open position.
[0016] Referring now to Figure 4, means for sensing movement of the rotatable part 18 relative
the body of the mixer 2 will be described. An activator 32 is attached to a region
of the retaining ring 30 and a switch 34 is provided on the body of the mixer 2. The
activator 32 and the switch 34 are so arranged that they are opposite one another
when the guard assembly 14 is fully closed. The switch 34 and activator 32 are such
that when the activator 32 is opposite the switch 34, the switch 34 will be in a first
of two states and when the activator 32 moves away from the switch 34, the switch
34 assumes the other state. Therefore, when the rotatable part 18 of the guard assembly
14 is moved from the closed position, either intentionally or by accident, the activator
32 will move away from the switch 34, so causing the switch 34 to change state, i.e.
to trip.
[0017] The switch 34 is connected in such a way as to control the motor. In the first state,
with the guard assembly 14 fully closed, the switch 34 permits energisation of the
motor and therefore the rotor, and hence mixing implement 6, is capable of operating
in a normal manner. However in the second state, when the rotatable part 18 is moved
and the switch 34 tripped, the motor will be disenabled, so that the mixing implement
6 within the bowl cannot rotate. As soon as the guard assembly 14 is closed again,
the rotor will be enabled and the mixer may be used in the normal manner when the
rotatable part is not in the closed position.
[0018] The housing 24 is provided with means, such as a bayonet attachment 36, for connecting
the guard assembly 14 to the body of the mixer. The guard assembly may be a standard
fitting of the mixer or may be obtained separately and fitted to an existing machine.
The guard assembly may be completely removed from the mixer, for example for cleaning.
This will cause the switch to trip and render the mixer inoperable.
1. A food mixer comprising a body, a bowl releasably mounted on the body, a motor for
moving a food processing implement within the bowl and a guard assembly above the
bowl comprising two parts, complementary in shape, one of which is rotatable between
at least two positions, a first closed position in which it prevents access to the
bowl and a second open position about or within the second part, which second part
is mounted in a fixed position relative to the bowl.
2. A food mixer as claimed in Claim 1, wherein the rotatable and fixed parts of the guard
assembly are both partially hemispherical in shape.
3. A food mixer as claimed in Claim 1 or Claim 2, wherein a portion of the guard assembly
comprises spaced bars.
4. A food mixer as claimed in any preceding Claim, wherein the rotatable part of the
guard assembly is secured to the fixed part thereof by means of a fixing device.
5. A food mixer as claimed in any preceding Claim, wherein the guard assembly is removably
mounted to the body.
6. A food mixer as claimed in any preceding Claim, wherein means are provided for sensing
movement of the rotatable part of the guard assembly relative to the body operatively
connected to, or integral with, means for preventing energisation of the motor.
7. A food mixer as claimed in Claim 7, wherein the sensing means comprises a switch and
an activator therefor provided respectively on the body of the mixer and the rotatable
part of the guard assembly, the switch when activated by the activator preventing
energisation of the motor, the activator being arranged to activate the switch when
the rotatable part of the guard assembly is not in the closed position.
8. A food mixer as claimed in Claim 8, wherein the switch and the activator are so positioned
as to be directly opposite each other when the rotatable part of the guard assembly
is in the closed position.
9. A food mixer as claimed in any preceding Claim, wherein the rotatable part of the
guard assembly is so mounted that it is free to move in response to pressure thereon
from the contents of the bowl.
10. A food mixer as claimed in any preceeding Claim, wherein means is provided to prevent
energisation of the motor when the bowl is not in a predetermined position relative
the body.