WO2008090303A2

WO2008090303A2 - Safety system

Info

Publication number: WO2008090303A2
Application number: PCT/GB2007/004674
Authority: WO
Inventors: Roland Eden
Original assignee: Kenwood Limited
Priority date: 2007-01-23
Filing date: 2007-12-06
Publication date: 2008-07-31
Also published as: WO2008090303A3; GB2445953A; GB0701205D0

Abstract

A mechanical safety system comprises a detent member (26), associated with an attachment (10) and comprising a tubular collar arranged coaxially with the drive axis. The collar (26) is capable of bidirectional movement along the axis, between first and second positions and is arranged so that, in the first position, it physically prevents the processing tool (12, 14) of an attachment (10) from being driven by the appliance. The collar (26) is urged towards the first position, and is locked thereat so long as a container (16), forming part of the attachment (10), remains open. When the container (16) is closed, safely enclosing the tool (12, 14), the system responds to such closure by freeing the collar (26) for movement towards the second position, thus allowing the tool (12, 14) to be driven by the appliance. The invention also provides an attachment (10), for an electrically powered kitchen appliance, incorporating such a safety system.

Description

SAFETY SYSTEM

This invention relates to safety systems and it relates especially, though not exclusively, to such systems associated with attachments for electrically operated kitchen appliances, such as stand mixers and the like, which are capable of supporting and driving various attachments, usable for purposes such as juice extraction.

Juicer attachments typically contain macerating plates formed with teeth or other implements capable, when rotated at reasonably high speeds within a bowl-like container, of pulping or shredding fruits and vegetables to extract juice therefrom; the macerating plate usually forming part of the base of a basket which constrains the fruit to be pulped or shredded, and permits juice to be separated from unwanted pulp residues. The basket and macerating plate are typically rotated by means of a powerful electric motor incorporated in the stand mixer and thus can present significant risk to users, as well as to children and others who may interfere with unattended appliances, unless appropriate safety measures are provided to ensure that the basket and macerating plate cannot be driven unless they are properly encased within the bowl-like container, and the latter is securely closed by a lid.

Attachments for kitchen appliances manufactured by most reputable companies have such safety measures, and most existing measures work reasonably well under most circumstances. However, there is a continual quest to implement such safety measures by means of safety systems exhibiting improved security and robustness, and moreover legislation is continually being introduced to ensure that adequate safety standards are established and met. Furthermore, many existing safety systems rely upon the actuation of an electrical switch to break the power supply to the motor unless safe operating conditions obtain. However, in the event that a switch becomes faulty or damaged, it may not break the power supply and thus may permit operation of an appliance under unsafe conditions. The present invention thus aims to provide a purely mechanical safety system which conforms to all current safety legislation and which, moreover, is user-friendly. The invention also aims to provide an attachment, for an electrically powered kitchen appliance, incorporating such a safety system.

According to the invention there is provided a mechanical safety system for selectively permitting a motor to drive an implement, within a container, in rotation about an axis; the motor driving a spigot device configured to engage in driving relationship a drive coupling associated with the implement, and the system further comprising a detent member, associated with the implement, means for locking said detent member in a disabling position along said axis, at which it physically inhibits engagement of said spigot device with said drive coupling, and means for responding to encasement of the implement by the secure latching of a lid to the container by releasing said detent member for movement, along said axis, away from said disabling position sufficiently to permit the engagement of said spigot device with said drive coupling.

Preferably, the detent member comprises a tubular collar, disposed coaxially with said axis of rotation and resiliency urged towards said disabling position. It is further preferred that the collar is locked in said disabling position by means of a pin member disposed transversely of said axis and engaging in an aperture in said collar.

Preferably, the system further comprises means for moving said pin member lengthwise in response to secure latching of said lid to said container, to change the relationship between said pin and said aperture, thereby freeing the collar to move from said disabling position.

The invention also encompasses a kitchen appliance incorporating a safety system in accordance with any of the foregoing.

In order that the invention may be clearly understood and readily carried into effect, one embodiment thereof will now be described with reference to the accompanying drawings, of which:

Figure 1 shows, in cross-sectional view, part of a system in accordance with one example of the invention, with the implement constrained against rotation; and

Figure 2 shows, also in cross-sectional view, the same part of the system with the implement free to be driven in rotation by the motor.

The drawings, in which consistent numbering is adopted throughout, show in partial cross-section, a juicer attachment 10 for a stand mixer

(not shown) or for an alternative domestic appliance containing an electric motor and providing a suitable drive outlet, as indicated in part by a drive spigot 50, for the attachment 10.

In this example, the juicer attachment 10 incorporates an implement in the form of a rotating basket 12, the base 14 of which comprises a macerating plate as is well known; the implement 12, 14 being housed within a bowl-like container 16 and driven in rotation from beneath by way of a drive shaft 18 which carries at its distal end a drive coupling 20, engageable with the drive spigot 50 so as to be driven thereby. The longitudinal axis of the drive shaft 18 defines the axis of rotation of the implement 12, 14, so it will be understood that the drawings , show one half of the system; the other half being a mirror image of what is shown. It will also be understood that the system as a whole, in this example, exhibits circular symmetry about the aforementioned axis of rotation.

The container 16 is intended to be closed, prior to use of the implement 12, 14, by means of a lid 22 which is securely latched in place by means of a pair of diametrically opposed stirrups, one of which is shown at 24, thereby safely encasing the implement 12, 14. The safety system of this invention is therefore intended, in this example, to prevent the implement 12, 14 being driven in rotation by the stand mixer's drive outlet, unless the lid 22 is securely latched in place by means of the stirrups.

Accordingly, in this example of the invention, the safety system includes a detent member in the form of a tubular collar 26 associated with the implement 12, 14 and its container 16, and coaxially disposed with the drive shaft 18. The collar 26 can, as will be described more fully hereinafter, be locked in a disabling position (as shown in Figure 1) along said axis, at which it physically inhibits engagement of the drive coupling 20 on the drive shaft 18 with the drive spigot 50. The collar remains locked in the disabling position until such time as the lid 22 is secured to the container 16 by means of the two stirrups such as 24, at which time the collar 26 is released (as shown in Figure 2) for movement along said axis, towards the implement 12, 14, and thus away from the disabling position, sufficiently to permit the engagement of the drive coupling 20 with the drive spigot 50.

The collar 26 is resiliency urged towards the disabling position shown in Figure 1 by means of a coil spring 28, and it is locked in that position by means of a pair of diametrically opposed pin members, such as that shown at 30, disposed transversely of the drive shaft 18 and engaging in respective key-hole shaped apertures, such as that shown at 32, in the collar 26; the apertures such as 32 being elongated, as shown, and being larger at the top than at the bottom thereof.

In this example of the invention, the system further comprises means for moving the pin members such as 30 lengthwise towards the drive shaft

18 in response to secure latching of the lid 22 to the container 16, to change the relationship between the pins such as 30 and their respective apertures such as 32, such as to align a reduced-diameter section, such as

31, of each pin with its respective keyhole slot; the reduced diameter section such as 31 of the pins such as 30 being dimensioned to pass through the relatively narrow section of the respective keyhole-shaped slot such as 32, thereby freeing the collar 26 to move from the disabling position shown in Figure 1, against the resilient force imposed by the spring 28, to permit the drive coupling 20 to engage with the spigot 50, as shown in Figure 2.

Each of the pins such as 30 is resiliently urged, by means of a respective coil spring, such as that shown at 34, towards the position which it occupies when the collar 26 is in the disabling position shown in Figure 1, and it will thus be appreciated that the system is resiliently loaded, both by spring 28 and by the two springs such as 34, into a safety mode represented by the disabling position.

Each pin member such as 30 is mounted on a respective slider block, such as that shown at 36, for linear motion towards and away from the drive shaft 18; each slider block such as 36 having an end stop such as 38 which it encounters when in the disabling position shown in Figure 1.

When the stirrups such as 24 are moved inwardly, towards a position at which the lid 22 is latched to the container 16, the slider blocks such as 36 are moved away from the end stops such as 38 by engagement with noses, such as that shown at 40 of respective hinge blocks such as that shown at 42, carried by the aforementioned stirrups 24. Each hinge block such as 42 pushes its respective slider block 36, and thus its associated pin member 30, radially towards the drive shaft 18 (against the resilient urge imposed by the spring 34) so as to align the aforementioned reduced-diameter section 31 of pin member 30 with the keyhole slot 32. This permits the collar 26 to move axially (upwards in the drawings) against the resilient force imposed by the spring 28 so that the attachment 10 can be seated correctly for use on the stand mixer, with the drive coupling 20 drivingly engaged with the spigot 50. A latch 44, actuated by an over-centre link arm 46 is provided to engage with a shaping 48 on the nose 40 of the hinge block 42 thereby to latch the stirrup 24 securely to the container 16.

Once securely latched, as described above, the stirrup 24 cannot be unlatched until the attachment 10 has been removed from the stand mixer (i.e.. until the drive coupling 20 has been withdrawn from the spigot 50), because the collar 26 remains pushed upwardly, trapping the pins such as 30 with their reduced-diameter sections such as 31 in the relatively narrow sections of the keyhole slots such as 32. When the attachment 10 is removed from the stand mixer, the collar 26 is driven downwards by the spring 28, realigning the pin members such as 30 with the relatively wide sections at the top of the keyhole slots such as 32. This frees the pin members for movement, under the influence of the respective springs, such as 34, back towards their stable positions in the safety mode, once the stirrups such as 24 are released by the user, thereby releasing the latch 44 in response to movement of the over-centre link arm 46.

The invention also encompasses an attachment, for an electrically powered kitchen appliance, incorporating a safety .system as described herein.

Claims

CLAIMS:

1. A mechanical safety system for selectively permitting a motor to drive an implement (12, 14), within a container (16), in rotation about an axis; the motor driving a spigot device (50) configured to engage in driving relationship a drive coupling (20) associated with the implement (12, 14), and the system further comprising a detent member (26), associated with the implement (12, 14), means (30) for locking said detent member (26) in a disabling position along said axis, at which it physically inhibits engagement of said spigot device (50) with said drive coupling (20), and means (36, 30/31) for responding to encasement of the implement (12, 14) by the secure latching of a lid (22) to the container (16) by releasing said detent member (26) for movement, along said axis, away from said disabling position sufficiently to permit the engagement of said spigot device (50) with said drive coupling (20).

2. A system according to claim 1, wherein the detent member (26) comprises a tubular collar, disposed coaxially with said axis of rotation.

3. A system according to claim 2, including means (28) for resiliently urging said tubular collar (26) towards said disabling position.

4. A system according to claim 2 or claim 3, further including a pin member (30), disposed transversely of said axis, adapted to lock said collar (26) in said disabling position by engagement with a key-hole shaped aperture (32) in said collar (26).

5. A system according to claim 4, comprising means (34) adapted to resiliency urge said pin member (30) towards a position locking said collar (26) in said disabling position.

6. A system according to claim 4 or claim 5, further comprising means (40, 42) for moving said pin member (30) lengthwise in response to secure latching of said lid (22) to said container (16), thereby to change the relationship between said pin (30) and said key-hole shaped aperture (32), and freeing the collar (26) to move from said disabling position.

7. A system according to claim 6, wherein said pin member (30) comprises a rod-like component having, over a major part of its length, a diameter substantially conforming to a relatively wide dimension of said key-hole shaped aperture (32); said rod-like component further having, at a predetermined location (31) along its length, a diameter substantially conforming to a relatively narrow dimension of said key-hole shaped aperture (32).

8. A system according to any preceding claim, further comprising a pair of user-actuable stirrup members (24) for securing said lid (22) to said container (16).

9. A system according to claim 8, comprising means (40, 42) associated with said stirrups (24) for releasing said detent member (26) from its locked condition in said disabling position when the lid (22) is secured to the container (16).

10. An attachment, for an electrically powered kitchen appliance, incorporating a safety system in accordance with any preceding claim.