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EP 1 239 553 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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21.05.2008 Bulletin 2008/21 |
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Date of filing: 05.03.2002 |
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International Patent Classification (IPC):
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Electrical connectors
Elektrische Verbinder
Connecteurs électriques
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Designated Contracting States: |
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DE FR GB IT NL |
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Priority: |
05.03.2001 GB 1054089
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Date of publication of application: |
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11.09.2002 Bulletin 2002/37 |
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Divisional application: |
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07019907.0 / 1887665 |
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Proprietor: STRIX LIMITED |
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Ronaldsway,
Isle of Man IM9 2RG (GB) |
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Inventor: |
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- Parkes, David
Isle of Man IM9 4AF (GB)
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Representative: Samuels, Adrian James |
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Frank B. Dehn & Co.
St Bride's House
10 Salisbury Square London EC4Y 8JD London EC4Y 8JD (GB) |
(56) |
References cited: :
US-A- 5 144 217
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US-A- 5 971 810
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] This invention relates to electrical connectors, more particularly those of the sort
which may be engaged regardless or substantially regardless of their relative angular
orientation. It applies particularly, but not exclusively, to such connectors for
use in liquid heating vessels.
[0002] So-called 360° connectors have now become well known in kettles and jugs to those
skilled in the art. In the most popular form of such connectors, the Strix P72, the
cordless appliance has, on its underside, a central line pin and two concentric annular
conductors. The smaller diameter conductor is for the neutral component of the mains
supply, whilst the outermost one is an earth connection. The corresponding base part
of the connector has a central aperture for the line pin surrounded by an annular
slot for receiving the neutral ring. Electrical connection is made via sprung contacts
inside the base connector part below the aperture and a portion of the annular slot
respectively, which are biased against the line pin and neutral ring respectively.
The base connector part fits within the outermost earth ring of the appliance connector
part and has an outwardly sprung contact on one side for making connection to the
inner face of the earth ring. Further details of these connectors is given in
WO 95/08204 and
US 5971810.
[0003] Clearly for such a connection system to be safe, it must not be possible for a user
to gain casual access to the live electrical contacts. In the connectors described
above this is achieved by making the aperture and annular slot sufficiently narrow
to prevent access by even a small child's finger. An international standard accordingly
prescribes a maximum width which standard is easily met by the above-mentioned connectors.
Although not necessary to meet the safety standards, a further safety criterion is
applied to the P72 cordless connector - namely that it should not be possible to insert
any item of ordinary household cutlery such as the tip of a knife or the handle of
a teaspoon into the aperture or slot to gain access to the contacts. The narrow width
and curvature of the annular apertures in the P72 ensure this.
[0004] It has recently been proposed by the applicant, in
PCT/GB00/03901, published under
WO 01/28294, to provide a 360° connector with additional annular slots (and corresponding additional
annular conductors on the appliance part of the connector) to provide additional poles
- e.g. for connecting a pair of thermal sensors in the appliance to an electronic
temperature control in the base part. Since the original annular slot is the same
diameter as before, the two additional outermost slots are necessarily larger. Their
consequently shallower curvature means that although the slots are still sufficiently
narrow to satisfy international safety standards, there is a greater chance that they
would not pass the additional test outlined above, albeit that the contacts in the
outer slots are not at dangerous mains potential.
[0005] Moreover other examples can be envisaged where it would be desirable to have a similar
connection system with larger and thus less curved, annular slots.
[0006] This disadvantage of larger diameter slots could be offset by correspondingly reducing
the width of the slot. However this would make it more difficult to mate the two halves
of the connector and may increase the chance that the annular conductors in the appliance
part are damaged by improper mating.
[0007] The present invention aims to provide such an arrangement with improved resistance
to insertion of foreign objects and provides a cordless electrical connector part
comprising at least one annular slot for receiving an annular contact member and an
electrical contact disposed in said slot for making electrical connection with said
annular contact member in use, wherein a portion of said annular slot in the vicinity
of said contact is locally narrower than the rest of the slot.
[0008] It will be seen by those skilled in the art that by narrowing the slot locally in
the vicinity of the contact, insertion of a foreign body into the slot such that it
may touch the electrical contact therein is made more difficult.
[0009] The narrowing of the slot could be effected at any point along the depth thereof,
or could even be throughout the depth of the slot. Preferably however the narrowing
is limited in depth and most preferably is set in from the mouth of the slot. This
gives the benefit of ensuring that the narrowing does not interfere with the most
critical initial mating between the connector parts during use.
[0010] The narrowed portion could take various forms. For example it could be a smooth reduction
in the width or a step change. The profile of the narrowed portion could be in the
form of a continuous lip. More preferably however it comprises a series of discrete
projections e.g. in a castellated arrangement. This is beneficial in that it helps
to prevent liquid collecting on the connector by allowing it to drain through. It
might even, in some embodiments, give the projections sufficient give to allow a mould
tool to be withdrawn past them to facilitate a one-piece moulding. In the preferred
embodiment however the projections are formed at the split line between the two halves
of the mould tool.
[0011] As mentioned above, the invention is particularly applicable to annular slots of
a larger diameter than that presently used for the neutral ring in the P72. However
it is not restricted to larger diameter slots. It could also be used for example to
allow the width of a smaller slot to be increased where standards permit whilst maintaining
the same degree of resistance to penetration by a foreign object in the vicinity of
the contact.
[0012] The applicants have further realised that with a connector of increased diameter,
percentage manufacturing tolerances will give rise to potentially increased lateral
play between the two connector parts, and has therefore devised means at least partially
to alleviate this problem. According to a preferred embodiment therefore, the connector
part comprises means on the outer housing thereof for properly laterally locating
the corresponding connector part when the two are fully engaged.
[0013] Thus it will be seen that in accordance with this preferred embodiment, freer lateral
engagement can be achieved prior to full engagement to assist in the engaging of the
two parts, but when they are fully engaged the locating means will serve properly
to locate the two connector parts relative to one another by preventing any significant
unwanted lateral movement. This is important,
inter alia, to ensure that the electrical contacts in one connector part maintain good electrical
contact with the annular conductors or pins. This is particularly so where the contact
is made against the end of the conductors since the contact area will tend to be relatively
small.
[0014] In preferred embodiments such location means also acts to provide alignment of the
annular conductor on the appliance connector before it encounters the narrowed portion
of the annular slot. This is clearly applicable where, as is preferred, the narrowed
portion is set in from the mouth of the slot.
[0015] Preferably the first connector part is provided on the cordless base and the second
connector part on the cordless appliance. Preferably the connector parts are of the
type which permit engagement irrespective of their relative angular orientation.
[0016] The location means could provide some degree of location from when the two connector
parts begin to engage, but preferably it provides location only in the final stages
of engagement. An example of a suitable such means is a lip extending around the base
of the connector (and therefore which will come into contact with the other connector
part only as the two parts are brought into full engagement). Preferably however a
plurality of circumferentially spaced protrusions, most preferably four, is provided.
This will give a slight saving in material costs.
[0017] The locating means preferably has an outer engagement surface substantially parallel
to the axis of the connector, i.e. the direction in which the two connector parts
are brought together for engagement, but a slight taper is preferred, e.g. 1-2°, so
that the thickness of the locating means at the very bottom can be chosen to give
a tight location between the connector parts at the fully engaged position, without
hampering the final stage of engagement which could otherwise tend to result in a
user failing to engage the parts fully.
[0018] As before, this aspect of the invention is particularly applicable to larger diameter
annular cordless connectors but may be applied equally to those of conventional size
or even non-360° connectors e.g. having a rectangular shape.
[0019] A preferred embodiment of the present invention will now be described, by way of
example only, with reference to the accompanying drawings in which:
Fig. 1 is a plan view of the base part of a 360° cordless electrical connector in
accordance with the invention;
Fig. 2 is a view of the underside of the connector part of Fig. 1;
Fig. 3 is a cross-section on the line A-A of Fig. 2;
Fig. 4 is a side view of the connector part of Figs. 1 to 3;
Fig. 5 is a cross-section on an axis through two diametrically opposed locators; and
Fig. 6 is a view similar to Fig. 3 showing two connector parts being engaged.
[0020] Turning to Figure 1, there is shown a plan view of the base part of a 360° cordless
connector in accordance with the invention. This allows a cordless appliance to be
supplied with electrical power regardless of its relative angular orientation. The
basic principles of this arrangement are set out in
WO 95/08204.
[0021] In common with the connection system disclosed in
WO 95/08204, to which reference should be made for further details, the base connector part shown
in Fig. 1 has a central aperture 2 to receive the line pin of the corresponding appliance
connector part. Although not visible in the accompanying drawings, an earth tab is
also provided, projecting from the periphery of the connector part to engage on the
inner surface of the outermost earth ring of the appliance connector in exactly the
same way as is described in
WO 95/08204.
[0022] Outwardly of the central aperture 2 is an annular slot 4 for receiving an annular
conductor of the appliance connector part. Two further concentric annular slots 6,
8 are designed to receive two corresponding further annular conductors of the appliance
part of the connector (see conductors 28, 30 in Fig. 6).
[0023] Leaf spring contacts provided within the connector part (not shown) make electrical
contact in use with the ends of the line pin and the annular conductors respectively
(see e.g. contacts 18, 20 in Figs. 3 and 6).
[0024] In the depicted embodiment the outermost annular slot 8 provides connection to the
mains neutral pole. This means that it is as spaced as possible from the line aperture
2 which further enhances safety.
[0025] The two additional poles 4, 6 of the connector may, for example, provide electrical
connection to a pair of thermal sensors on a thick film heating element in the appliance
from an electronic control circuit in the base.
[0026] The two additional annular slots 6, 8 are provided outwardly of the first annular
slot 4 and are therefore greater in diameter with correspondingly lower curvatures.
In order to make it more difficult to insert foreign objects into the two outer slots
6, 8 in view of their lower curvature, two series of circumferentially spaced restrictions
10, 12 respectively are provided in the slots 6, 8. This arrangement enhances drainage
of spilt water through the connector.
[0027] When viewed from the orientation of Fig. 1, the restrictions 12 provided in the outermost
slot 8 are substantially at the top of the slot, whilst the restrictions 10 in the
next slot in 6, are at the bottom of the slot. The reason for these locations is that
they are the portions of the respective slots 6, 8 in which the leaf spring contacts
are provided.
[0028] Although the leaf springs have been omitted from the underside view in Fig. 2 the
mounting location 14 for the outermost slot contact and the mounting location 16 for
the contact for next most outward slot 6 may be clearly seen. These mounting locations
14, 16 are positioned so that, when installed, the leaf spring contacts will be beneath
the respective restrictions 10, 12 in the slots 6, 8.
[0029] This arrangement is shown more clearly in the cross-section of Fig. 3. From this
the ends of the leaf spring contacts 18, 20 may clearly be seen in the two outermost
annular slots 6, 8 respectively. Furthermore restrictions 10, 12 are provided in the
annular slots 6, 8 in the region of these contacts. Thus additional protection against
insertion of foreign objects is provided where it is required most - i.e. to prevent
the foreign object from being able to touch the electrical contacts 18, 20.
[0030] It will be seen from Fig. 3 that even when the intended annular conductors are inserted
into the annular slots 6, 8, when the ends of the conductors reach the restrictions
10, 12 there will only be a small range of angles from the vertical that will allow
the conductors to be inserted past the restrictions 10, 12.
[0031] In order to prevent any problems with the ends of annular conductors in the appliance
connector part catching or sticking on the restrictions 10, 12, a series of four circumferentially
locators 22 is provided around the base of the upwardly projecting portion 24 of the
connector part. This may be seen in the side and cross-sectional views respectively
of Figs. 4 and 5. The locators 22 take the form of projections both horizontally and
vertically from the sloping surface of the base of the upwardly projecting portion
24 of the connector part. As may be seen most clearly from Fig. 5, the outward facing
surfaces 22a of the locators 22 are in fact inclined by an angle of approximately
1-2° from the vertical towards the central axis of the connector part. It can also
be seen that the horizontal edges of the locators 22 are rounded.
[0032] In use the appliance connector part, comprising an outer earth skirt within which
are three concentric annular conductor and a central pin, is brought towards the base
connector part shown in the drawings. First contact is made between the two connector
parts when the outer earth skirt contacts the rounded upper edge 26 of the base connector
part. The shape of the edge 26 allows the appliance connector to be 'rolled' into
proper alignment with the base connector part. The annular conductors and central
pin of the appliance connector then begin to enter the corresponding apertures 2 to
8 in the base part.
[0033] As the two connector parts are brought closer into engagement, the outer earth skirt
will engage the outer facing surfaces 22a of the four locators 22. This is shown in
Fig. 6. The locators substantially reduce any lateral play between the two connector
parts and ensure that the two outermost annular conductors 28, 30 are able to pass
cleanly through the restrictions 10, 12 in the annular slots 6, 8 to make contact
with the spring leaf contacts 18, 20. The slight bevel on the locators 22 allows the
finally engaged position to be tight whilst avoiding catching during engagement.
[0034] Apart from any benefit in guiding the annular conductors through the restrictions
in the annular slots, the four locators 22 ensure that, when fully engaged, the two
connector parts are a tight fit. This is despite the fact that their relatively larger
size could otherwise mean relatively more lateral play due to manufacturing tolerances.
[0035] Thus it will be seen that the described embodiment provides a multi-pole 360° connector
which allows easy initial engagement and a firm positive final engagement. Furthermore,
access to the electrical contacts within the base connector by a foreign object -
e.g. the handle of a teaspoon - is prevented: by the tight curvature of the inner
apertures 2, 4; and by a combination of curvature and width restrictions 10, 2 in
the outer slots 6, 8.
1. A cordless electrical connector part comprising at least one annular slot (6,8) for
receiving an annular contact member (28,30) and an electrical contact (18,20) disposed
in said slot (6,8) for making electrical connection with said annular contact member
(28,30) in use, characterised in that a portion (10,12) of said annular slot (6,8) in the vicinity of said contact (18,20)
is locally narrower than the rest of the slot (6, 8).
2. A connector part as claimed in claim 1 wherein the narrowing of the slot (6,8) is
limited in depth,
3. A connector part as claimed in claim 2 wherein said narrowing is set in from the mouth
of the slot (6,8).
4. A connector part as claimed in claim 1, 2 or 3 wherein the narrower portion (10,12)
of the slot (6,8) comprises a series of discrete projections.
5. A connector part as claimed in any preceding claim comprising means (22) on the outer
housing (24) thereof for properly laterally locating a corresponding second connector
part when the two are fully engaged.
6. A connector part as claimed in claim 5 wherein said location means (22) also acts
to provide alignment of an annular conductor of the second connector part on the connector
part before it encounters the narrowed portion (10,12) of the annular slot (6,8).
7. A connector part as claimed in claim 5 or 6 wherein the connector part is provided
on the cordless base of an appliance and the corresponding second connector part is
provided on a cordless appliance.
8. A connector part as claimed in claim 7 wherein the connector parts are of the type
which permit engagement irrespective of their relative angular orientation.
9. A connector part as claimed in any of claims 5 to 8 wherein said location means (22)
provides location only in the final stages of engagement.
10. A connector part as claimed in any of claims 5 to 9 wherein said location means (22)
comprises a plurality of circumferentially spaced protrusions.
11. A connector part as claimed in any of claims 5 to 10 wherein said locating means (22)
has an outer engagement surface (22a) substantially parallel to the axis of the connector.
12. A connector part as claimed in claim 11 wherein said outer engagement surface (22a)
has a slight taper such that the thickness of the locating means (22) at the very
bottom is chosen to give a tight location between the connector parts at the fully
engaged position, without hampering the final stage of engagement.
1. Schnurloses elektrisches Verbindungsstück, das wenigstens einen ringförmigen Schlitz
(6, 8) zum Aufnehmen eines ringförmigen Kontaktelements (28, 30) und einen elektrischen
Kontakt (18, 20), der im Schlitz (6,8) angeordnet ist, um eine elektrische Verbindung
mit dem ringförmigen Kontaktelement (28, 30) im Gebrauch herzustellen, umfasst, dadurch gekennzeichnet, dass ein Abschnitt (10, 12) des ringförmigen Schlitzes (6, 8) in der Umgebung des Kontakts
(18, 20) lokal enger ist als der Rest des Schlitzes (6, 8).
2. Verbindungsstück nach Anspruch 1, wobei die Verengung des Schlitzes (6, 8) in der
Tiefe begrenzt ist.
3. Verbindungsstück nach Anspruch 2, wobei die Verengung ausgehend von der Mündung des
Schlitzes (6, 8) einsetzt.
4. Verbindungsstück nach Anspruch 1, 2 oder 3, wobei der Verengungsabschnitt (10, 12)
des Schlitzes (6, 8) eine Reihe diskreter Vorsprünge umfasst.
5. Verbindungsstück nach irgendeinem der vorangehenden Ansprüche, das Mittel (22) an
seinem Außengehäuse (24) umfasst, um ein entsprechendes zweites Verbindungsstück in
geeigneter Weise lateral anzuordnen, wenn die beiden vollständig in Eingriff sind.
6. Verbindungsstück nach Anspruch 5, wobei das Anordnungsmittel (22) auch bewirkt, dass
ein ringförmiger Leiter des zweiten Verbindungsstücks auf das Verbindungsstück ausgerichtet
wird, bevor er in den verengten Abschnitt (10, 12) des ringförmigen Schlitzes (6,
8) eintritt.
7. Verbindungsstück nach Anspruch 5 oder 6, wobei das Verbindungsstück an der schnurlosen
Basis eines Gerätes vorgesehen ist und das entsprechende zweite Verbindungsstück an
einem schnurlosen Gerät vorgesehen ist.
8. Verbindungsstück nach Anspruch 7, wobei die Verbindungsstücke dem Typ entsprechen,
der einen Eingriff unabhängig von ihrer relativen Winkelausrichtung erlaubt.
9. Verbindungsstück nach irgendeinem der Ansprüche 5 bis 8, wobei das Anordnungsmittel
(22) nur in den letzten Phasen des Eingriffs für eine örtliche Anordnung sorgt.
10. Verbindungsstück nach irgendeinem der Ansprüche 5 bis 9, wobei das Anordnungsmittel
(22) mehrere in Umfangsrichtung beabstandete Vorsprünge umfasst.
11. Verbindungsstück nach irgendeinem der Ansprüche 5 bis 10, wobei das Anordnungsmittel
(22) eine Aufieneingriffsfläche (22a) aufweist, die im Wesentlichen parallel zur Achse
des Verbinders ist.
12. Verbindungsstück nach Anspruch 11, wobei die Außeneingriffsfläche (22a) eine leichte
Abschrägung aufweist, so dass die Dicke des Anordnungsmittels (22) an der untersten
Stelle so gewählt ist, dass sich eine feste örtliche Anordnung zwischen den Verbindungsstücken
in der vollständig in Eingriff befindlichen Position ergibt, ohne die Schlussphase
des Eingriffs zu erschweren.
1. Pièce de connecteur électrique sans fil comprenant au moins une fente annulaire (6,
8) pour recevoir un élément de contact annulaire (28, 30) et un contact électrique
(18, 20) disposé dans ladite fente (6, 8) pour établir le raccordement électrique
avec ledit élément de contact annulaire (28, 30) à l'usage, caractérisée en ce qu'une partie (10, 12) de ladite fente annulaire (6, 8) à proximité dudit contact (18,
20) est localement plus étroite que le reste de la fente (6, 8).
2. Pièce de connecteur selon la revendication 1, dans laquelle le rétrécissement de la
fente (6, 8) est limité en profondeur.
3. Pièce de connecteur selon la revendication 2, dans laquelle ledit rétrécissement se
présente sous la forme de l'embouchure de la fente (6, 8).
4. Pièce de connecteur selon la revendication 1, 2 ou 3, dans laquelle la partie plus
étroite (10, 12) de la fente (6, 8) comprend une série de saillies distinctes.
5. Pièce de connecteur selon l'une quelconque des revendications précédentes, comprenant
des moyens (22) sur son boîtier extérieur (24) pour positionner latéralement correctement
une seconde pièce de connecteur correspondante lorsque les deux sont complètement
mises en prise.
6. Pièce de connecteur selon la revendication 5, dans laquelle lesdits moyens de positionnement
(22) agissent également pour fournir l'alignement d'un conducteur annulaire de la
seconde pièce de connecteur sur la partie de connecteur avant qu'elle ne rencontre
la partie rétrécie (10, 12) de la fente annulaire (6, 8).
7. Pièce de connecteur selon la revendication 5 ou 6, dans laquelle la pièce de connecteur
est prévue sur une base sans fil d'un appareil et la seconde pièce de connecteur correspondante
est prévue sur un appareil sans fil.
8. Pièce de connecteur selon la revendication 7, dans laquelle les pièces de connecteur
sont du type qui permet la mise en prise indépendamment de leur orientation angulaire
relative.
9. Pièce de connecteur selon l'une quelconque des revendications 5 à 8, dans laquelle
lesdits moyens de positionnement (22) fournissent le positionnement uniquement lors
des étapes finales de la mise en prise.
10. Pièce de connecteur selon l'une quelconque des revendications 5 à 9, dans laquelle
lesdits moyens de positionnement (22) comprennent une pluralité de saillies espacées
de manière circonférentielle.
11. Pièce de connecteur selon l'une quelconque des revendications 5 à 10, dans laquelle
lesdits moyens de positionnement (22) ont une surface de mise en prise externe (22a)
sensiblement parallèle à l'axe du connecteur.
12. Pièce de connecteur selon la revendication 11, dans laquelle ladite surface de mise
en prise externe (22a) a une légère conicité de sorte que l'épaisseur des moyens de
positionnement (22) au plus profond, est choisie pour donner un emplacement serré
entre les pièces de connecteur à la position complètement mise en prise, sans gêner
la dernière étape de mise en prise.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only.
It does not form part of the European patent document. Even though great care has
been taken in compiling the references, errors or omissions cannot be excluded and
the EPO disclaims all liability in this regard.
Patent documents cited in the description