Note: Descriptions are shown in the official language in which they were submitted.
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This application is a division of our Canadian patent application
Serial no. 325,910 filed April 19, 1979.
The invention relates to an electric household blender having an
attachable device in which cutting tools driven by a motor rotate, and a motor
base with an electric switch.
In known devices of this type, if the material to be processed in the
container is quite thin, the rotor often continues to rotate for several seconds
after being turned off. If the user is not careful, he runs the danger of
placing his hand in the container too early, before the blades have stopped, and
severely injuring himself.
In order to protect the user of a household blender from injury by
the still rotating blades, it has already been proposed ~German Publication
2,228,189, Mantelet, August 30, 1973) to close the control circuit of a brake
device of the motor as soon as the lid is removed from the container with the
material to be processed. For this purpose the electrical circuit of the drive
motor includes one or more switches connected in series, whose movable switch
element can assume either an operating position in which the electrical circuit
is closed, or a rest position in which this electrical circuit is open, whereby
the movable switch element has one contact which in the rest position closes
the control circuit of the brake device of the motor. Moving the switch out
of the brake position to turn the blender on is effected by pressing the lid
against the container. This known blender has the disadvantage that the user
must continually press the lid of the device downward during operation, and
cannot leave it unattended. Furthermore, the known blender cannot be combined
with auxiliary units such as a mixer, citrus press or meat grinder, because
these units require a firm anchor with the motor base.
The object of the present invention is to provide an electric household
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blender in which, after the motor is turned off, all danger of injury from
still rotating blades is eliminated and which allows the provision of auxiliary
units. The apparatus is formed such that the user of the blender need not
remain next to the apparatus during its operation. Finally, the type of inter-
locking mechanism for the attachable device is formed such that the attachable
device can have a different free diameter than that of the motor base.
This object is achieved according to the invention in that the contain-
er is held by a container holder with lock bolt supports which can be placed on
the motor base and which can be locked with lock bolts by means of a locking
ring, for which purpose the locking ring, which is held and guided in the motor
base, is rotatable about the longitudinal axis of the motor base and can be
moved by a lock bolt. It cooperates with a lock bar which can be moved longi-
tudinally in the motor base, and which in turn releasesor locks the operating
switch for turning the motor on and off, depending on the position of the locking
ring.
The motor base and container holder are advantageously provided with
guide surfaces, whereby the container holder has lock openings or slots in the
vicinity of the guide surfaces as lock bolt supports, in which lock bolts or
studs engage. These lock bolts or studs are arranged on the movable lock ring
and are supported and guided in openings in the housing of the motor base.
The container is advantageously provided with guide surfaces, at
least two of which are arranged so as to be distributed on the circumferential
surface~ whereby each locking pocket is provided with a locking groove or lock-
ing slot and the locking pockets are enclosed in corresponding depressions
equipped with guide surfaces, which are provided on the motor base.
By means of the apparatus according to the invention, it is assured
that the apparatus can only be turned on when the container for the material to
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be blended or an au~iliary unit is placed on the motor base and is rigidly
locked thereto. The unlocking procedure and subsequent removal of the contain-
er holder requires so much time that the motor will surely have stopped before
contact with the tools or blades is possible.
The invention allows a wide variety of possible embodiments. One of
these is schematically illustrated in the attached drawings, wherein:
Figures 1 and 2 show an electric household blender in perspective
view, whereby the holder for the container for receiving the material to be
blended is shown separately from the motor base;
Figure 3 shows a partial section through the blender, whereby the
device for locking the container holder, part of the container and the contain-
er locked by the container holder are shown in section. The motor and wing
blades are not depicted for better visibility;
Figure 4 shows a perspective partial illustration of the container
holder with interlocking pocket;
Figure 5 shows a perspective partial illustration of the motor base;
Pigures 6 and 7 show a schematic and perspective illustration of the
basic parts of the device for locking the container holder to the motor base;
The container l, together with the container lid 10, is held by a
container holder 2 between the edge 20 of the container holder 2 on one side
and the motor base 4 on the other side. In order to be able to lock the contain-
er 1 with lid 10 to the motor base 4, said holder 2 has three interlocking
pockets 5 with guide surfaces 35, 36 37 uniformly distributed about its cir-
cumference. These guide surfaces are equipped with respective perpendicular
pins 7 and a lock bolt support 12 ~Figure 4). When the holder 2 is placed
on the motor base 4, the pins 7 move in the direction A of the arrows (Figure
4) and press against the lock bolts 8, three of which are distributed on the
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circumference of a lock ring 9 arranged in the inside of the motor base 4, and
thus make the interlocking mechanism (shown in Figures 6 and 7) ac~ivatable.
After placement of the h~der 2 and movement thereof in the direction
A, the lock ring 9 which is movably mounted in the motor base 4 ~Figure 6) is
pushed by the pins 7 in direction A against the force of springs 16. If the
lock ring 9 is then rotated in direction C by the lock bar 11, the lock bolt 8
becomes enclosed in the lock bolt support 12 (Figure 7). The horizontally ar-
ranged lock bolts 8 are held and guided for this purpose in L-shaped longitudi-
nal holes 13 cut in the housing wall of the motor base 4. The lock ring 9 also
has three longitudinal holes 17 distributed about its circumference whereby a
screw 14 with spring 16 passes through each of these longitudinal holes 17,
which screws 14 are attached at 15 to the motor base 4. The springs 16 press
the lock ring 9 upward against arrow direction A.
On the outside wall of the motor base 4 in the area of the L-shaped
longitudinal holes ~4, downwardly open guide studs 30 (Figure 5) with bores 28
are provided for the pins 7 of the interlocking pockets 5 so that they exactly
meet the lock bolts 8 of the lock ring 9 when the container holder 2 is placed
on the motor base 4. As shown in Figures6 and 7~ the lock ring 9 can be moved
in direction C or D with the aid of the lock bar ll, which is guided in a longi-
tudinal hole (not shown in greater detail) present in the housing wall of the
motor base.
In addition to a stud 24, with which it is enclosed in a recess 43
of the lock ring 9, the lock bar 11 also has a lock fork 25 which acts together
with the lock rod 26 movable in a perpendicular direction in the motor base 4
and in which, in turn, the studs 38 of the operating switch engage. When the
lock ring 9 is in the position shown in Figure 7, i.e., when the holder 2 is
locked by the bolts 8 and the lock bolt supports 12 after the lock bar 11 is
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moved in direction C, the lock rod 26 can be moved vertically upward in
direction E by rotating the operating switch 27 in direction G, so that the
lock rod 26 enters into the recess 29 of the lock fork 25. Only in this posi-
tion (Figure 7) can the operating switch 27 be rotated and the motor be turned
on to drive the wing blades. If the operating switch 27 is rotated in the
opposite direction G, the lock rod 26 falls vertically downward against the
direction E, so that the lock bar 11 can be moved in direction D. After the
lock bar 11 is moved in direction D (Figure 6), the lock rod 26 is locked,
because one end thereof abuts the shoulder 23, which renders the operating switch
27 incapable of rotating.
The exemplary embodiment of the holder 2 shown in Figure 3 is not only
suited to hold a lid on a container and lock both parts (10 and 1) to the motor
base 4, but rather the container 1 with lid 10 can be exchanged for a mixing unit,
a meat grinder or a citrus press. These auxiliary units only require a base
portion which corresponds in diameter d and height h (Figure 3) to the illu-
strated container 1 and lid 10. Because the holder 2 is provided on its upper
side with an opening o, parts of the auxiliary units can be formed in such a
manner that they project far beyond the holder 2. Finally, container holders
can be provided whose dimensions h and o are such that, for example with a
mixing unit, it is impossible for the user to reach the rotating blades with
the hand or fingers from the top through the opening. The inner surfaces of
the holder are effectively provided with ribs, cams or the like (not shown),
which reliably prevent the holder or the auxiliary unit from rotating about the
blade axis when the motor is turned on. The electrical control portion in the
motor base may also be provided with a known braking device, thus when the
motor is turned off, the control circuit of a braking device is closed so that
the motor instantaneously comes to a halt. Instead of an electrically operat-
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ing braking clevice, the lock bar 26 can also be coupled with a mechanically
operating motor brake. ~s soon as the lock bar moves opposite the arrow di-
rection E, i.e., when the motor is turned off, it presses a brake shoe (not
shown) against the motor shaft.
