HK1142502B - Improvements in or relating to stand mixers - Google Patents

Description

Improvements in or relating to vertical mixers

Technical Field

The present invention relates to stand mixers, which represent a class of motor-driven kitchen appliances in which a generally C-shaped housing provides a cradle-like base for a mixing bowl, a generally upright support portion, and a head unit extending above the cradle and supporting a downwardly facing drive output for driving one or more mixer tools performing a planetary mixing action in the bowl.

Background

Such vertical stirrers are well known and have been in use for many years. Over the years, agitators of this type have been constructed and developed to perform an unprecedented range of functions, and many such devices employ, for example, multiple drive outputs that operate at different speeds and have different torque characteristics to enable them to perform a wide range of operations.

Some of the most recently developed stand mixer constructions exhibit even more operating capability, since they comprise heating means for subjecting the ingredients in the bowl to a planetary mixing action while being heated; heating is optional, so that cooking, partial cooking, or simply heating of the ingredients may be accomplished.

However, whether or not any given stand mixer is equipped with heating means, it is desirable that the head of the mixer be movable relative to the remainder of the housing (and in particular relative to the bowl support tray) to facilitate insertion and removal of the mixing tool and bowl.

Typically, this movement of the head relative to the remainder of the housing is initiated by the user operating a mechanical catch which is actuated to release the head for pivotal movement upwardly in the general plane of the C-shaped housing under the action of a spring.

The head of such a beater is relatively heavy and it has therefore been found necessary to provide a relatively strong spring for urging the head upwardly after release of the catch. However, this arrangement is problematic because the relatively heavy head may move very quickly upwards and be stopped abruptly only when it reaches the end of its travel. Typically, the end of the head's stroke is defined by a relatively small area of contact between a portion of the head and a stationary portion of the housing, and this may result in a large force being transmitted to the remainder of the housing, thereby jarring the mixer and possibly causing the ingredients to spill out of the mixing bowl, or even the mixer to move relative to a work table or other surface on which it is used.

This arrangement also presents other problems in that some users of these relatively sophisticated blenders may perceive such sudden and relatively uncontrolled movement of the head as not matching the price and image of the blender.

In relatively more popular practice, the foregoing problems may become more acute because the drive motor of the stand mixer is disposed in the head, rather than in the upright portion of the generally C-shaped housing as in conventional practice, because disposing the motor in the head increases the relative weight of the movable head relative to the rest of the stationary portion of the housing.

Disclosure of Invention

It is an object of the present invention to provide a stand mixer in which the aforementioned problems are reduced or eliminated.

According to the present invention, there is provided from one aspect a stand mixer having a carrier for a mixing bowl; a motor; and a head disposed above the carriage in an operative position and supporting a drive output arranged to face the carriage and drivable by the motor to impart planetary mixing action to one or more tools depending from the drive output into the bowl; the stand mixer further comprising a mechanism for pivoting the head away from the bracket and out of the operative position, the mechanism comprising locking means for releasably locking the head to the housing in the operative position, and resilient means for urging the head away from the bracket; characterized in that a damping means is provided for limiting the speed of movement of the head. The aforementioned sudden stop of the head can be eliminated by the damping means, since the latter at least partially counteracts the strong elastic thrust provided by the spring.

Preferably, the damping means is arranged to limit the speed of movement of said head portion for at least a substantial part of said movement.

In some preferred embodiments, the damping means comprises a hydraulic damper. Furthermore, in such embodiments, it is preferred that the damping means comprise a piston movable in a tubular housing containing hydraulic fluid; the piston and the housing member are connected to the head and to another part of the housing, respectively, or to another part of the housing and to the head, respectively.

It is further preferred that the damping effect of the damping means is eliminated when the head is moved back towards the operating position. This is achieved in a preferred embodiment by providing a diversion passage through said piston for said fluid and a valve plate adapted to close said passage when the head is moved away from said carriage and out of said operative position.

It is particularly preferred that the damping means and the resilient means are located in the same location in a generally upright portion of the housing, and it is further preferred that the space for accommodating the damping means and the resilient means in the generally upright housing portion is provided by locating the motor in the head of the stand mixer.

Drawings

In order that the invention may be more clearly understood and readily put into practical effect, some embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 shows a conventional stand mixer in perspective view;

FIG. 2 shows the stand mixer of FIG. 1 from the front;

FIGS. 3a and 3b schematically illustrate a side view, partially in cross-section, of a stand mixer according to an embodiment of the invention;

fig. 3c shows an enlarged view of the damping mechanism for the stand mixer in fig. 3a and 3 b.

Detailed Description

Referring now to fig. 1 and 2, in which corresponding features are given the same reference numerals, a conventional stand mixer 10 includes a generally C-shaped housing 20 including a base 30 supporting a bowl support 40 and a head 50 connected by a generally upright housing portion 60. The housing 20 encloses a motor (which is not shown but is typically disposed within the generally upright portion 60 of the housing 20) and a transmission (not shown) that transmits motor power supplied by the motor to a plurality of drive outputs to which various tools may be attached for performing a wide variety of tasks in the kitchen.

In this particular embodiment, the head 50 supports a high speed blender drive output (behind the cover 51), a low speed shredder drive output (behind the cover 52), and a planetary drive port for food mixing indicated at "53" (above the carrier 40), although it will be readily appreciated that more, fewer, and/or different drive outputs may be provided depending on the intended function of the stand blender.

A stemmed mixing tool is attached to the socket 54 of the outlet 53 in a conventional manner, in use hangs into a mixing bowl mounted on the carrier 40, and is configured to rotate about both the axis of the socket 54 and the central axis 55 of the outlet 53, thereby performing a planetary mixing action. The relationship between the relative shapes and sizes of the bowl and mixing tool required to ensure adequate and repeatable ingredient mixing is well known and has been established in actual use for many years.

As shown, the stand mixer 10 is in this case provided with a pair of catches 41, 42 extending from an outer wall 43 of the bracket 40, which cooperate with a part at the bottom of the bowl to form a snap-lock system which ensures that the bowl is securely and quickly positioned on its platform. Other locking systems, such as screw-type systems, may be used as an alternative to snap locking, if desired.

The generally upright housing portion 60 of the housing 20 is provided with a demarcation line 67, suitable means allowing the head 50 of the stand mixer to be hinged away from the bracket 40 to facilitate insertion and removal of the mixing tool and bowl.

An embodiment of the invention will now be described with additional reference to figures 3a and 3b, in which equivalent parts are designated by the same reference numerals as in figures 1 and 2 and which schematically show, in simplified partial cross-section, key elements in a stand mixer according to an embodiment of the invention.

Referring now to FIG. 3a, the stand mixer 10 is shown in its operating position with a hinge 70 about which the head 50 is pivotally movable relative to the remainder of the housing 20. The head is releasably locked in its operative position by means of, as an example, a head release post 72, the tip 74 of which engages a recess 57 formed in a suitable location on the periphery of the head 50. When the post 72 is pressed sufficiently to disengage its end 74 from the notch 57, the head 50 is lifted away from the bracket 40 by the action of the spring 80 and moves out of the operating position shown in figure 3a towards the fully open position shown in figure 3 b. The spring 80 is connected between the mounting portion 58 attached to the head 50 and the mounting portion 62 adjacent the base of the generally upright and stationary portion 60 of the housing 20.

Bumpers 90 are also connected between corresponding mounting points on the head 50 and mounting points adjacent the generally upright portion 60 of the housing 20. The mounting points for the bumpers are shown at the numerals "59" and "64", respectively, and it can be seen that in this embodiment of the invention, the spring 80 and bumper 90 are arranged in parallel and are located substantially in the same location in the generally upright portion 60 of the housing 20. By arranging the drive motor of the stand mixer in the head 50 in this example, a space is provided for accommodating the spring 80 and the damper 90 in the above-described position. It has previously been common to locate the drive motor in the generally upright portion 60 of the housing 20. The damper 90 is pivotally mounted at 92 to allow a relatively small amount of lateral movement required to follow the movement of the head 50.

It will be appreciated that the spring 80 may be coiled around the damper 90 if desired to provide a compact unit, in which case of course measures must be taken to allow a small amount of pivotal movement of the damper 90 about its pivot 92.

It will be appreciated that in any event, this embodiment of the invention is capable of providing movement of the head 50 relative to the remainder of the housing 20 in a smooth and controlled operation, whereby the powerful action of the spring is counteracted to an extent sufficient to eliminate jerking of the head 50 and to smoothly stop the head when it reaches the limit of its open position shown in figure 3 b. It will also be appreciated that such a smooth action is not only desirable from the standpoint of avoiding the transmission of sudden jerky movements to the stand mixer 10, but also provides a controlled and pleasing action to give people the impression that this is a relatively expensive mixer.

The damping means, for example indicated by the reference "90", may be configured to provide different degrees of damping depending on the opening angle of the mixer, i.e. depending on the distance between the head 50 and the bracket 40. In one such arrangement, the damping force is arranged to be relatively small when the head 50 leaves the operating position shown in figure 3a, i.e. has just disengaged from the locking system provided by the members 57, 72 and 74; and the damping force steadily increases as the head 50 moves toward the fully open position shown in fig. 3b, such that at the point of maximum opening, the damping force substantially counteracts the spring force.

The head 50 is adapted to be returned under manual pressure from its open position shown in fig. 3b to its operative position shown in fig. 3a, and in this embodiment, the damping operation is cancelled when the movement is performed in this direction. As shown schematically in fig. 3c, the damper 90 includes a piston 92 that operates within an internal bore of a cylindrical housing 94 containing hydraulic fluid 96. By providing a flow-splitting passage 98 to allow fluid 96 to flow through the piston 92, the damping operation is eliminated; this passage is opened during the upward movement of the piston 92 associated therewith when the head 50 is closed towards its operating position. During the movement of the head 50 towards its open position, the passage 98 is closed by the valve plate 100 when the piston moves downwards, thus ensuring the desired damping operation.

Claims (9)

1. A stand mixer (10), comprising: a housing (20) having a cradle (40) for a mixing bowl; a motor; and a head (50) disposed above the carriage (40) in an operative position and supporting a drive output (53) arranged to face the carriage (40) and drivable by the motor to impart planetary mixing action to one or more tools depending from the drive output into the bowl; the stand mixer (10) further comprising a mechanism (72, 80) for pivoting the head (50) away from the bracket (40) and out of the operating position, the mechanism comprising locking means (72, 74, 57) for releasably locking the head (50) to the housing (20) in the operating position and resilient means (80) for urging the head (50) away from the bracket (40); characterized in that a damping device (90) is provided for limiting the speed of movement of the head (50).

2. A stand mixer according to claim 1, wherein the damping means (90) is arranged to limit the speed of movement of said head (50) over at least a substantial part of said movement.

3. A stand mixer according to claim 1 or claim 2, wherein the damping means (90) comprises a hydraulic damper (92, 94, 96).

4. A stand mixer according to claim 3, wherein the damping means (90) comprises a piston (92) movable in a tubular housing (94) containing hydraulic fluid (96); the piston (92) and the housing member (94) are connected to the head (50) and to another part of the housing (20), respectively, and vice versa.

5. A stand mixer according to claim 1 or claim 2, further including means (98, 100) for relieving the cushioning effect of the cushioning means (90) when the head (50) is moved back towards said operative position.

6. A stand mixer according to claim 4, further including a diverter passage (98) for said fluid (96) through said piston (92) and a valve plate (100) adapted to close said passage (98) when the head (50) is moved away from said bracket (40) and out of said operative position.

7. A stand mixer according to claim 1 or 2, wherein said damping means (90) and said resilient means (80) are disposed in the same location in a generally upright portion (60) of said housing (20).

8. A stand mixer according to claim 7, wherein a space for accommodating said damping means (90) and said resilient means (80) in said generally upright housing portion (60) is provided by placing said motor in a head portion (50) of the stand mixer (10).

9. A stand mixer according to claim 1 or claim 2, wherein the damping means (90) is arranged to provide different degrees of damping at different points in the movement.