GB2182381A - Locking device - Google Patents

Abstract

This invention relates to a locking device of the kind which comprises a housing 12 containing a rotable spindle 14 on which is mounted a rotor 13 so as to be rotatable therewith. The rotor is formed with a plurality of axially extending bores which contain key engageable pins such as pin 21 and the housing itself is also formed with a plurality of axially extending bores 22 in which are mounted a plurality of locking pins 23. Springs 24 serve to urge the pins 23 outwardly and pins 21 can be engaged by a key which can be moved axially to push the pins and the to positions in which their interengaging end surfaces lie in a common plane which contains an axial end of the rotor 13 to enable it to be turned relative to the housing 12 by turning said key. In accordance with the invention the rotor 13 is provided with an indicator pin 36 having an outer end which is coloured or shaped or otherwise marked or treated so as to be readily visibly distinguishable from the remainder of the rotor pins. Such visibly distinguishable indicator pin 36, (as shown in Fig. 3 pin 36 is rectangular rather than cylindrical), is thus arranged to provide a visible indication of the angular position of the rotor 13 relative to the housing 12. <IMAGE>

Description

SPECIFICATION Locking device This invention relates to a locking device of the kind which comprises a housing containing a rotatable operating spindle on which is mounted a rotor so as to be rotatable therewith, said rotor being formed with a plurality of axially extending bores which are circumferentially spaced around the rotational axis of the rotor and which contain key engageable pins and said housing being also formed with a plurality of circumferentially spaced axially extending bores in which are mounted locking pins each urged normally by resilient means to a position in which one of its ends projects outwardly from one of the housing bores and into an aligned rotor bore to prevent rotation of the rotor relative to the housing, either said key engageable pins or said locking pins being arranged so that they are not all of the same length and the key engageable pins being adapted to be engaged, at their ends opposite to said ends engaged by the locking pins, by a key having complementary formations which, on insertion of the key over the spindle and into the housing, will engage said opposite ends of the rotor pins whereby axial depression of the key will thereafter push the rotor pins and the housing pins to positions in which their inter-engaging end surfaces lie in a common plane which contains an axial end of the rotor to enable it and said spindle to be turned relative to the housing by turning said key.

The aforesaid operating spindle would be connected at its end remote from that end adapted to receive the aforesaid key to any mechanism or devide which it is desired should be controlled or lockable by said locking device. In one particular embodiment (which is not to be taken in any limiting sense) such mechanism may comprise an electrical switch which is capable, by appropriate angular movement of the associated key, of being set in any one of two or more different positions, said spindle then conveniently being connected at its inner end to a part carrying electrical contacts or contact engaging means.

With a locking device of the above-described kind there is commonly provided a front plate which is stationariiy mounted in the housing and which contains a central aperture through which the operative end of the associated key may be inserted. The periphery of said aperture in the front plate serves to engage parts of the adjacent end surfaces of the rotor pins to prevent them from being pushed out of the locking device by the pressures exerted on them through said resilient means acting on the locking pins and usually said central aperture of the front plate is formed with one or more short, outwardly extending, circumferentially spaced, generally radial extensions forming radial slots.Such radial slots (where more than one is provided) are spaced apart at a circumferential pitch which is the same as the circumferential pitch of the aforesaid rotor pins so that at least some of said rotor pins will engage the inner face of the front plate at positions therein which coincide with the radial extension slots of the front plate aperture. However, it is known to arrange that one of such radial slots does not have a rotor pin circumferentially aligned with it, the "open" slot thus provided forming a guide or location which is intended to help the user to position the key correctly which is then done by orienting the key so that a radially outwardly extending projection provided on the key can pass through said "open" slot.

The above-described arrangement suffers from the dosadvantage however that it is not always possible to see clearly the aforesaid "open" slot with which the key projection has to be aligned and consequently the orientation of the rotor relative to the housing cannot easily be determined. This of course is espe cialiy likely where the locking device is of a relatively small size or where it is used in a relatively dark environment.

The object of the present invention therefore is to provide an improved locking device of the kind specified which makes it easier for the user to align the associated key correctly and to determine the angular position of the rotor relative to the housing.

In accordance with the present invention there is provided a locking device of the kind specified wherein the rotor is provided with an indicator pin having an outer end which is coloured or shaped or otherwise marked or treated so as to be readily visibly distinguishable from the remainder of the rotor pins, said indicator pin being thus arranged to provide a visible indication of the angular position of the rotor relative to the housing.

The whole or part of said indicator pin may for example be formed of a material (such as a synthetic resin material) which is of a colour different from the colour of the material used to form the key engageable pins of the rotor.

Alternatively, said indicator pin may be marked or formed at least in part of a luminescent material. Furthermore, said indicator pin may be slidably mounted in its rotor bore so as to be engageable by a locking pin and co-act with it in forming part of the means which in use act as means locking the rotor to the housing. Alternatively, said indicator pin may be arranged so that it does not form part of said locking means.The indicator pin may be of generally circular or square or rectangular or any other convenient shape in crosssection whereas the remainder of the rotor pins may have a cross-sectional configuration of a form (for example circular) which is differ ent from the above-mentioned cross-sectional configuration of the indicator pin, such a difference in cross-sectional configuration providing in itself an easily identifiable indication of the position in which the key has to be inserted and of the angular position of the rotor relative to the housing. Furthermore, the indicator pin may be arranged at its outer end to project through the front plate.

The invention will now be more particularly described with reference to the accompanying drawings wherein Figure 1 is a sectional elevational view showing one example of a locking device in accordance with the invention, said device being combined in the example shown with an electrical switch, Figure 2 is a side view of a key which can be used in association with the locking device seen in Fig. 1, and Figure 3 is an end view, looking in the direction of arrow 'A', of the locking device seen in Fig. 1.

Referring now to the drawings there is shown in Fig. 1 a locking device generally indicated by reference numeral 10 which in this example is intended to be used in conjunction with an electrical switch generally indicated by reference numeral 11 although of course it is to be understood that the locking device can be used in other applications if desired.

The locking device includes a housing 12 in which is mounted a rotor 13. There is also provided a centrally extending operative spindle 14 which is connected to the rotor 13 by means of an integral projection or key 15 which projects into a slot or guideway 16 formed in the spindle. The inter-connected rotor 13 and spindle 14 are thus capable of rotation relative to the housing 12 about the axis of the spindle indicated by reference numeral 17. The inner end of said spindle 14 is connected to a part 18 which is rotatable with the spindle and which is itself connected to further components forming part of the aforementioned switch, the latter being provided with a plurality of projecting terminals 19.There is also provided a spring loaded ball detent mechanism 20 which will rotate with the part 18, the balls of said mechanism serving to co-act with a plurality of depressions formed in the adjacent part of the interior wall of the housing in order to establish a plurality of circumferentially spaced predetermined switch positions as in use the aforesaid rotor 13 is rotated. The details of the aforementioned switch mechanism 11 however form no part of the present invention.

The rotor 13 is formed with a plurality of circumferentially spaced axially extending bores recesses which contain a plurality of key engageable pins. One of such pins is indicated in Fig. 1 by reference numeral 21.

These pins are not all of the same length and conveniently may be of generally cylindrical form so as to be of circular configuration in cross-section. For example five of such key engageable pins may be provided as indicated in Fig 3. The housing 12 is also formed with a plurality of circumferentially spaced axially extending bores 22 which serve to receive a plurality of locking pins 23 which are of hollow cylindrical form and a spring 24, located between the bottom of a bore 22 and the interior of the closed outer end of the associated pin 23 serves to urge each of such pins 23 (which are conveniently the same length) outwardly to a position as shown in Fig. 1 in which the outer end of each pin 23 enters into an aligned bore or recess of the rotor 13.

Said pins 23 thus provide locking elements which, in the position shown in Fig. 1, prevent rotary movement of the rotor 13 relative to the housing 12.

It will however be understood that if the several key engageable pins 21 are depressed so as in turn to push the pins 23 back into the bores 22 until the outer end surfaces of said pins 23 lie in a plane which contains the inner end surface of the rotor 13 (i.e. the right-hand end surface of said rotor as seen in Fig. 1) then the rotor will be free to rotate.

Accordingly there is provided a key 25 (see Fig. 2) having a handle part 26 and a projecting hollow pin engaging part 27. Around the outer surface of said part 27 adjacent to the outer or free end thereof there are formed a plurality of short grooves such as grooves 28 and 29 which respectively provide at their inner ends shoulders such as 30 or 31 which are spaced from the outer end of said part 27 by different distances.Thus the arrangement is such that the aforesaid shoulders at the inner ends of said grooves formed in the part 27 of the key are adapted, when the key is inserted into the locking mechanism 10 so that its hollow part 27 extends around the outer end of the spindle 14 then the rotor pins 21 will be pushed inwardly by different distances but to positions in which the outer closed ends of the pins 23 will lie in a common plane with the adjacent axial end of the rotor 13 as explained above. The rotor is then in the position in which it can be turned by the key. There is conveniently provided a projection which extends into the interior of the bore formed in the part 27 of the key 25, such projection engaging with the slot or groove 16 which forms a keyway in the spindle 14.

The outer end of said housing 12 is closed by a cap 32 and located between said cap and the housing is a front plate 33 (see also Fig. 3) having a central aperture 34 through which the free end part 27 of the key will extend as it is applied to the outer end of the spindle 14. Said central aperture has a major portion of generally circular configuraton which however is formed with an outwardly extending radially directed slot 35 which in the posi tion of the rotor seen in Figs. 1 and 3 is aligned with the end of a further pin 36 which in fact acts as an indicator pin. The rotor pins 21 are each arranged so that a portion of the outer end of each pin engages the interior surface of said front plate 33 and such engagement prevents said pins 21 from being pushed out of the locking mechanism by the pressure exerted by said springs 24.In the case of the indicator pin 36 however the outer end of such pin does not engage the interior surface of the front plate 33 but is prevented from being pushed out of the locking mechanism by the provision of an inner flange 37 which in the outermost position of said pin 36 engages a shoulder formed in the interior of the rotor 13.As will be seen from Fig. 1 said indicator pin 36 also acts in conjunction with a housing pin 23 in order together to form part of the locking mechanism but in an alternative arrangement the indicator pin 36 does not act in conjunction with a housing pin 23 and therefore does not form part of the locking mechanism and in this case it may be mounted in a bore or recess formed in the rotor 13 which has a closed lower end a further spring being then provided so as to urge the indicator pin 36 towards its outer position in which the aforesaid flange 37 engages the shoulder formed in the rotor. The key 25 is also provided with a radially outwardly extending projection 38 which, when the key is properly aligned with the locking mechanism will pass through the radial slot 35 formed in the front plate 33 so as to engage the outer end of the indicator pin 36.As the key is further pushed over the spindle 14 then the indicator pin 36 will be pushed inwardly into the rotor 13 together with the other rotor pins 21.

As will be seen from Fig. 3 the indicator pin 36 is of rectangular or square configuration in cross-section which is of course different from the cross-sectional configuration of the other rotor pins 21 and this difference alone will serve to indicate the angular position of the rotor relative to the housing and will provide a guide for the correct orientation of the key before it is inserted into the locking mechanism. Additionally or alternatively however said indicator pin 36 may be formed (as for example from a synthetic resin material) so that it is of a different colour than that used for the other rotor pins 21 but as yet a further alternative said indicator pin may be formed or treated in such a way that its outer end is luminescent.

In the case where only one radial slot 35 is formed in the front plate 33 as above described then once the key has been inserted over the end of the spindle 14 and pushed inwardly to free the above described locking mechanism to permit turning of the rotor 13 then the rotor can be turned and set into any angular position (as determined by the aforementioned detent mechanism 20), the key then remaining in position on the spindle whilst the aforementioned projection 38 remains at an angular position which is spaced from the radial slot 35. In an alternative construction however more than one of such radial slots 35 may be provided and such additional radial slots are indicated in Fig. 3 by dotted lines 39 and 40 thus providing two further radial slots in the example shown. If the key is therefore inserted into the locking mechanism and over the end of the spindle 14 with the key projection 38 aligned with the indicator pin 36 the rotor can be turned to either of two positions in which said projection 38 is aligned with radial slot 39 or radial slot 40 (corresponding in the present example to two further switch positions) whereafter the key can be withdrawn and this will prevent any further alteration to the setting of the associated switch 11 until the key is again inserted into the locking mechanism. In this case however, as well as in the case where there is only one radial slot 35 the initial position for which the key has to be properly orientated is clearly indicated by the aforesaid indicator pin 36.

Claims (8)

1. A locking device of the kind specified wherein the rotor is provided with an indicator pin having an outer end which is coloured or shaped or otherwise marked or treated so as to be readily visibly distinguishable from the remainder of the rotor pins, said indicator pin being thus arranged to provide a visible indication of the angular position of the rotor relative to the housing.

2. A locking device as claimed in Claim 1 wherein said indicator pin is formed of a material of a colour which is different from the colour of the material used to form the key engageable pins of the rotor.

3. A locking device as claimed in Claim 1 wherein said indicator pin is marked or formed at least in part of a luminescent material.

4. A locking device as claimed in any one of the preceding claims wherein said indicator pin is siidably mounted in its rotor bore and is engageable by a locking pin which, together with the indicator pin, forms in use part of means for locking the rotor to the housing.

5. A locking device as claimed in any one of the preceding claims wherein the indicator pin is formed so as to have a cross-sectional shape which is different from the cross-sectional shape of the remainder of the rotor pins.

6. A locking device as claimed in any one of the preceding claims wherein the housing is provided with a front plate having an aperture through which in use the operative end of the associated key is inserted, said indicator pin being arranged so that its outer end projects through said aperture in the front plate.

7. A locking device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

8. A locking device as claimed in any one of the preceding claims in combination with an electrical switch having a movable part which is connected to said rotor so as to be angularly movable therewith.