GB2529881A - Drive centralising arrangement - Google Patents

Abstract

A centralising arrangement for aligning complementary driving elements of a rotatable tool assembly and a motor driven drive outlet presented on a housing containing an electric motor, wherein the tool assembly incorporates a spring-loaded safety system and said complementary driving elements are prevented from entering into driving engagement unless the tool assembly is securely housed with a container. The arrangement further comprises a spring loaded guide ring 34 for engaging with a component surrounding the drive outlet in order to centralise the container on the drive outlet. The container may comprise a bottomless goblet of a blender or liquidiser. The guide ring may be attached to the goblet base assembly by means including clips 52 adapted to snap-fit into elongated apertures in said goblet base assembly.

Description

DRIVE CENTRALISING ARRANGEMENT

This invention relates to arrangements usable to centralise accessories or attachments, such as blender goblets and food processing bowls, with cliive couplings provided on fl-ce-standing host appliances and used to power the accessory or attachment. Hereinafter, reference will be primarily made to use of the invention in the context of blender goblets, but it will be appreciated that the invention is equally applicable to food processing bowls and, in general, to containers in which foodstuffs or other materials may be worked on by means of electrically-driven tools.

It is well known that electrically-driven kitchen appliances, such as blenders and food processors, generally comprise a free-standing base unit, containing an electric motor and associated control switches and operational circuitry, and one or more accessories or attachments which can be coupled to a drive outlet, presented on an external surface of the base unit, in order to drive a suitable food-processing tool housed within a container in which the processing or blending operations take place.

Typically, the drive outlet is presented on a flat-upwardly-facing surface of the base unit and the base of the container of the accessory or attachment is provided with a complementary drive socket capable of mating with the drive outlet so as to pick up drive from the motor in the base unit and use it to power the tool when the container is correctly placed on the base unit. In order to operate the accessory or attachment, the container is placed on the base unit so as to dock the drive socket on the container with the drive outlet on the base unit.

The tools used for food processing iii such appliances are usually sharp and rotated at high speed, so provision is requ red to ensure that the tools cannot be coupled to the drive outlet unless they are properly and safely housed within their containers. One efficient way of achieving a required degree of safety in this respect is described, in the context of a blender attachment, in GB-A-2426695. It will be appreciated that, since the attachments, such as blender goblets, have no electrical supply absent their coupling to the base unit, it is desirable that the safety provisions are mechanically operated, thus making the attachments intrinsically safe.

Typically, with such arrangements as described above, the safety provision operates on a spring-loading principle, whereby, unless the tool assembly is safely housed, ready for operation, in its container, its drive socket is prevented from engaging with the drive outlet of the appliance.

In the system described in the aforementioned patent application, this is achieved by means of a sprung collar which engages with the surround of the drive outlet and urges the drive outlet and the drive socket apart, thus preventing engagement between them imless the spring force is overcome; a requirement that can be met only if the blade assembly is housed within a container of sufficient weight. In alternative systems, a spring-loaded clutch-like mechanism is used to break the drive path between the drive socket and the tool.

In either event, the tool can only be driven when the complete attachment, comprising the blade assembly housed within its container, is placed on the drive unit and the attachment is correctly placed on the free-standing drive unit, whereupon the aforementioned spring loading is overcome by the weight of the attachment, including the container, which pennits the.

drive outlet and drive socket to dock.

The spring-loading is necessarily quitc powerful and users can encounter difficulty in successfully docking the drive socket on the attachment with the drive outlet on the base unit, as the spring force can tend to deflect the attachment from its desired upright docking position if the attachment is not presented correctly to the base. This difficulty tends to be exacerbated because the user is forced, by the nature of the arrangement, to attempt the docking procedure "blind", i.e. with the container itself obscuring the user's view of the drive outlet on the base unit.

It is an object of this invention to reduce or overcome the above-mentioned difficulty and, according to the invention, there is provided a centralising arrangement for aligning complementary driving elements of a rotatable tool assembly and a motor-driven drive outlet presented on a housing containing an electric motor, wherein the tool assembly incorporates a spring-loaded safety system whereby said complementary driving elements are prevented from entering into driving engagement unless the tool assembly is securely housed within a container; the arrangement further comprising a spring-loaded guide ring for engaging with a component surrounding said outlet in order to centralise the container on the drive outlet.

In one preferred embodiment of the invention, the container comprises a bottomless goblet of a blender or liquidiser and the tool assembly is associated with a goblet base assembly to which the goblet is attachable to form a goblet assembly comprising the goblet, the goblet base assembly and the blade assembly.

It is further preferred that the guide ring is attached to the goblet base assembly by means including clips adapted to snap-fit into elongated apertures in said goblet base assembly.

In some preferred embodiments of the invention, said safety system comprises means for resiliently urging a component of said tool assembly outwardly with sufficient force to prevent engagement of said complementary elements unless the container is of sufficient weight to overcome the force associated with said resilient urge. Preferably, the force associated with said resilient urge is at least 20 Newtons.

The invention also encompasses a blender, liquidiser or food processor incorporating any of the aforesaid arrangements.

hi order that the invention may be clearly understood and readily carried into effect, one embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows, in perspective and exploded view, a tool assembly for a blender suitable for use with an arrangement in accordance with the invention; Figures 2 and 3 show, in exploded view, additional components of the blender and a centralising arrangement in accordance with one embodiment of this invention; and Figure 4 shows in cross-sectional view an arrangement according to the aforesaid embodiment of the invention in operative position on a goblet assembly for a blender.

Referring now to the drawings, in which consistent numbering is adopted throughout, certain components of the system to be described, including the electrical drive motor and the controls therefor, are housed within a free-standing base unit (not shown) of a kitchen appliance; in this case a liquidiser/blender. Figure 1 shows a tool assembly 10 for the appliance, configured for mounting into the base of a goblet 12 (shown in part in Figure 4) or other container in which blending, liquidising or some other operation is to take place.

The assemblylO comprises a blade set 14 which can be driven from a drive socket 16 which is intended to dock with a complementary drive outlet (shown schematically at 18 on Figure 4) presented on an upwardly-facing surface of the aforementioned base unit. The electric motor provided in the base unit may be of any type convenient and suitable for use in the context of the appliance in question.

In order to ensure that the blade set 14 caimot be driven unless the tool assembly 10 is securely momted into the base of the goblet 12, there is provided a spring-loaded safety system, configured such that the drive socket 16 can dock with the drive outlet 18 on the base unit only if the blade assembly is safely housed within the goblet 12.

In this example, a force of at least 20 Newton is required to overcome the resilient urge and allow the necessary docking of drive socket 16 with its drive outlet 18.

The resilient urge can be provided and achieved in a number of ways, but in this example the safety system employs three linear coil springs 20a, 20b and 20c; each located over a respective spring locating pillar such as 22a and 22b (the third of these pillars cannot be seen in Figure 1).

An annular, sprung collar 24 is provided on its outer surface with arcuate cut-outs 26a, 26b and 26c, located and dimensioned to accommodate respective screw pillars 28a, 28b and 28c, into which screws 32a, 32b and 32c are respectively screwed in order to fixedly attach a closure ring 30 to the assembly 10. The sprung collar 24 can move axially relative to the assembly 10, and thus with respect to the closure ring 30; the collar 24 being finnly urged into its outward position by the springs 20a, 20b and 20c. This is a safe position, in which the coupling drive socket 16 cannot engage with tile drive outlet 1 8 n the base unit.

When, however, the blade assembly is correctly fitted into the base of the goblet 12, and the attachment as a whole is placed on the base unit, the weight of the goblet provides the force (in excess of 20 Newton) needed to overcome the resilient force provided by the springs 20a, 20b and 20c, thereby pushing the sprung collar 24 upwards and permitting the drive socket 16 to engage with the motor drive shaft 18 and thus to be driven thereby.

Referring now to Figures 2 to 4, a drive centralising arrangement in accordance with one embodiment of the invention utilises a sprung guide ring 34 which sits proud of the aforementioned sprung collar 24 to centralise die attachment around an annular upstand 36 surrounding the drive shaft of the base unit of the appliance whilst the goblet 12 is being placed on the base unit to set it up for use.

The blade assembly 10, which includes the sprung collar 24 and the drive socket 16, is fitted within a goblet base assembly 38 which comprises of a goblet base 40, the guide ring 34 and a pair of springs 42a and 42b.

A flange 44 on the blade assembly 10 is retained within the goblet base 40 by engagement with the lower lip of an open bottomed goblet 12 which can be attached to the base 40 by known means, such as a screw thread or a bayonet fixing.

The springs 42a and 42b are retained in the goblet base assembly 38 on respective posts 48a and 48b and the fit into respective pockets 50a and SOb on the guide ring 34. The guide ring in turn is slidably attached to the goblet base assembly 38 by means of four snap-fitting clips such as 52, which promote ease of assembly.

The goblet base 38 is formed with four elongated apertures such as 54 to accept the engagement of respective snap fit clips 52, the elongation being in the required axial direction of movement of the guide ring 34 relative to the base 38. Associated with each aperture such as 54 is a pair of guide ribs such as 56a aiid 56b, which sit either side of each snap-fitting clip 52 to prevent rotation, thereby ensuring that the rotation required to attach the assembly to the drive socket 16 does not misalign the springs 42a, 42b or assert excess force on the clips 52.

The guide ring 40 is designed to protrude enough to allow engagement with the upstand 36 but is sufficiently softly sprung to allow the goblet base assembly 38 to sit flush when installed to the top of the power unit.

Accordingly, the ring 34 assists a user to centralise the goblet assembly onto the drive outlet by engaging with the upstand 36 whilst the downward pressure is applied to overcome the spring-loading applied to the collar 24 by the safety system.

Although the invention has been described with reference to its association with a specific safety system, it will be appreciated that it can be used with advantage in association with many alternative safety systems. Descriptions of two further examples of such alternative safety systems can be found in (}B-A-2414381 and in (}B-A-2417538, and a further safety system usable to advantage with the present invention is described and claimed in our co-pending patent application (Agent's Ref P43 586GB) of even filing date herewith.

Claims (6)

1. Claims: 1. A centralising arrangement for aligning complementary driving elements of a rotatable tool assembly and a motor-driven drive outlet presented oii a housing containing an electric motor, wherein the tool assembly incorporates a spring-loaded safety system whereby said complementary driving elements are prevented from entering into driving engagement unless the tool assembly is securely housed within a container; the arrangement further comprising a spring-loaded guide ring for engaging with a component surrounding said outlet ill order to centrahise the container on the drive outlet.
2. 2. An arrangement according to claim 1, wherein the container comprises a bottomless goblet of a blender or liquidiser mid the tool assembly is associated with a goblet base assembly to which the goblet is attachable to fonim a goblet assembly comprising the goblet, the goblet base assembly and the blade assembly.
3. 3. An arrangement according to claim 2, wherein the guide ring is attached to the goblet base assembly by means including clips adapted to snap-fit into elongated apertures in said goblet base assembly.
4. 4. An arrangement according to any preceding claim, wherein said safety system comprises means for resiliently urging a component of said tool assembly outwardly with sufficient force to prevent engagement of said complementary elements unless the container is of sufficient weight to overcome the force associated with said resilient urge.
5. 5. An arrangement according to claim 4, wherein said force associated with said resilient urge is at least 20 Newtons.
6. 6. A centralising arrangement substantially as herein described with reference to andlor as shown in Figures 2 to 4 of the accompanying drawings.