GB2156893A - A door lock for a lighting column - Google Patents

Abstract

A lighting column door lock comprises a body member (10), a shroud (12) a claw-shaped latch (14), a spindle (16) and a compression spring (18). The body member (10) comprises three integrally formed tubular sections (30, 32, 34) the largest being provided with a rim (36) which locates it to the door.The largest section (30) has a slot (38) formed therein through which the latch (14) projects to engage with the inside wall (26) of the lighting column. In the closed position, the spring 18 urges the boss (52) to hold the latch against the inside wall of the lighting column. To release the latch a key member is used to press the spindle axially inwards against the spring (18) until the latch (14) aligns with a part circumferential region of the slot (38) and can be rotated free. <IMAGE>

Description

SPECIFICATION A door lockfor a lighting column The present invention relates to a door lock for a street lighting column.

Doors are provided near ground level in street lighting columns for the purpose of maintenance of the electric supply and where applicableto the timing mechanism which switches the street light on and off during the evening and morning lighting up times.

Conventional doors for street lighting columns are frequently bolted by one or two bolts to prevent them being opened ortampered with by the public. In order to open the door for maintenance purposes it is necessary to undothese bolts, each bolt requiring anything between 10 and 20 turns. This operation is not only tiring to perform but is also very time consuming. Also afterthe appropriate maintenance has been carried out, all the bolts have to be tightened securely.

It is therefore an object of the present invention to provide a door lock for a lighting column which is simpie to operate whille still being relatively vandal proof.

According to the present invention there is provided adoorlockforalighting column including: a hollow body member projecting inwards from the door, and having a part circumferential slot; a slidable and rotatable latch member provided within the body member, said latch member having a stub member for engagement bya keythroughthe hollow body memberfrom outside, and a claw member engaging the inside ofthe column when in the locked position; and spring means for urging the latch memberto a position it cannot rotate in order to hold the door locked; the door being unlocked with the aid ofthe key by sliding the latch against the spring means until it comes into alignment with the circumferential slot in the body member to enable it to be rotated to unlock the door.

The present invention will now be described in greater detail by way of example with reference to the accompanying drawings, wherein: Figs. 1 A and 1 B are respectively a side elevation view and an end elevation view ofthe body ofthe door' lock for a street lighting column; Figs. 2A, 2B and 2C are respectively a crosssectional view, a plan view, and an end view ofthe body of the door lock shown in Fig. 1; Figs. 3A and 3B are respectively a plan view and an end view ofthe shroud in Fig. 1; Figs. 4A and 4B are respectively a side elevation view and an end elevation view ofthe latch shown in Fig. 1; and Fig. 5 is a plan view ofthe spindle shown in Fig. 1.

Referring firstto Figures lAand 1B,the lockforthe street lighting column comprises a body member 10, a shroud 12, a latch 14, a spindle 16, a spring 18, a star lock washer 20 and a steel washer 22.

As shown in Figs. IA and 1B the body member 10 is secured in a substantially shaped circular slot in the upper part of the door 24ofthe street lighting column 26; the upper end ofthe latch 14engaging behind the column in order to hold the door in the closed position.

The body member 10 is shown in greater detail in Figs. 2A and 2C. As shown in Fig. 2A, it comprises three integ rally formed tubular sections 30,32 and 34 of diminishing size from the largest section 30 to the smallest section 34. The section 30 is provided with a rim 36 by which it is located with the doorto project inwards therefrom. A part ofthe section 30, is cut away to form a slot 38, which slot as cam be seen from Fig.

2C extends through an angle which is substantially greaterthan 90 . this slot 38, extending about twothirds of the distance from where the section 30 joins the middle section 32 towards the rim 36. Near the rim 36, parts 40 of the wall ofthe section 30 extend outwards to form a slot 42.

The shroud 12 shown in Figs. 3A and 3B consists of a one pieceelement44 having a slot 46, which when placed over the body member 10 is aligned sothata slot 38 matches the slot 46 to allow the latch to project therethrough. A rim 48 at one end is slightly curved to enable the shroud to fitflush with the inner surface of the column door 24. The shroud 12 is provided with a circular aperture 49to enable the section 34to project therethrough. In a modified form, the other end 50 of the shroud 12 is slightly tapered as shown in Fig. 3A.

The latch 14 in Figs. 4A and 4B comprises a substantially cylindrical shaped boss member 52, on to which there is secured or integrally formed therewith a substantiallytriangularshaped key holder 54. A claw shaped member 56 is attached to the upper part ofthe boss 52. Athreaded hole 58 is provided on thatflatface of the boss which is opposite to that on which the key holder 54 is secured. In modified form the thread may be replaced with an annular ridge in the hole 58.

The spindle 16, which is shown in greater detail in Fig. 5, has a threaded portion 60 to enable itto be screwed into the holde 58 in the boss 52 of the latch 14.

In modified form the thread may be replaced by a groove which engages a ridge in hole 58. The spring 18 is in the form of a compression coil spring which has a internal diameter which is slightly greaterthan the diameter ofthe spindle 16, and thus can slide over the spindle. One end ofthe spring abuts against the boss 52 of the latch ?4through the steel washer 22, whilstthe other abuts against a shoulder33 formed between the sections 32 and 34 of the body member 10. When the lock is in the locked position, the end of spindle opposite to the th readed end is just flush with the open end of the smaller section 34 of the body member 10.

The star lock washer 20 is provided to hold the shroud 12 in position by gripping the outer surface of the section 34 of the body member 10 and holding it againstthe inside face of door 24.

When the door lock is in the locked position, i.e. the claw shaped member is upright as shown in Fig. 18, the claw makes contact behind the claw makes contact behind the column 26 in order to hold the door 24 in the closed locked position.

In orderto open the doorfor maintenance purposes a special key (not shown) is inserted overthe triangular key holder 54. The operatorfirst pushes on the keywhich causes the latch I4to move backwards in the body member 10 againstthe action of the spring 18which is compresses, until the rearface of the latch 14contacts a shoulder31 formed between the sections 30 and 32. In this position the key can be turned anti-clockwise, the latch 14 rotating in the slot 38 ofthe section 30 ofthe body member 10.The rotation ofthe latch 14 means that the claw shaped member moves out of contact with the column 26so thatthe door 24 can be opened.

When the door24 is closed afterthe maintenance has been completed, the key is again inserted in the trianguiar key holder 54 and rotated clockwise. As soon as the sides of latch 14 come into align with the wall parts 40 defining the slot 42, the spring 18 urges the latch 14forwards to that the claw member 56 which now upright again is urged into contact with the inside wall ofthe column 26 in orderto hold the door 24 in the locked position.

Itwill be appreciated thattheabove described door lockfor a street lighting column is easy to operate with possession ofthe special key to unlock the door, and yet is substantially vandal proof and atthe same tims does not present a hazard to passers-by as the curved surface of the rim 38 protects the key holder 54 against it causing any damage to clothing orotherarticles which may come into accidental contact with the base ofthe lighting column.

Moreoverall parts of the door lock are made or corrosion resistant material, such as glass filled nylon forthe body member, and stainless steel forthe other parts such as the latch, the key holder, the spindle and the spring, which means that the door lock is unaffected by weather and atmospheric pollution.

Alternatively some parts can be made from piastics materials.

In standard form the lock accommodate from 2.9 to 6.3 mm column wall thickness, alternatively the shape ofthe claw member 56 can be adapted to suit different thicknesses of column wall and other details.

The above described door lockthus enables the maintenance operatorto quickly open and close the door, withoutthe need for undoing heavy duty bolts which are both tiring and time consuming.

Claims (14)

1. Adoorlockfora lighting column including: a hollow body member projecting inwards from the door, and having a part circumferential slot; a slidable and rotatable latch member provided within the body member, said latch member having a stub memberfor engagement by a keythroughthe hollow body memberfrom outside, and a claw member engaging the inside of the column when inthe locked position; and a spring means for urging the latch memberto a position in which it cannot rotate in orderto hold the door locked; the door being unlocked with the aid of the key by sliding the latch againstthespring means until it comes into alignment with the circumferential slot in the body memberto enable itto be rotated to unlock the door.

2. A door lock according to claim 1, wherein the hollow body member comprises three integrally formedtubuiarsections of diminishing size from one end ofthe body memberto the other.

3. A door lock according to claim 2, wherein the largesttubularsection is provided with a rim bywhich it is located with the door of the lighting column to project inwards therefrom.

4. A door lock according to any one of the preceding claims, wherein the slot extends through an angle which is substantially greaterthan 90".

5. A door lock according to claims 3 and 4, wherein the slot extends abouttwo-thirds ofthe distance from where the largest section of hollow body member joins to middle section towards the rim.

6. A door lock according to any one ofthe preceding claims, wherein a shroud consisting of a one piece element having a slot is positioned over the body member, said slot being aligned with the part circumferential slot ofthe body member, the latch member projecting therethrough.

7. A door lock according to claim 6, wherein the shroud is provided with a curved rim to enable it to fit flush with the inner surface ofthe door of the lighting column.

8. A door lock according to any one of the preceding claims, wherein the latch membercompris- es a substantially cylindrical boss member and a trangularshaped key holder constituting the stub member.

9. A door lock according to claim 8, wherein the claw member is secured to the upper part of the boss member.

10. A door lock according to claim 8 or9, wherein the cylindrical boss member is provided of a threaded hole into which a spindle having a threaded portion can engage.

11. A door 'ock according to any one ofthe preceding claims, wherein said spring means is a compression coil spring.

12. A door lock according to claim 10 and 11, wherein the internal diameter ofthe compression coil spring is sUightly greaterthan the diameter of the spindle, to enable it to slide overthe spindle.

13. A door lock according to claim 2 and 6, wherein a star lock washer is provided to hold the shroud in position by gripping the outer surface ofthe smallest tubular section and holding it againstthe inside face of the door ofthe lighting column.

14. A door lock for a lighting column, constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.