GB2497271A - Lock assembly with key obstructing central pin - Google Patents

Abstract

A lock comprising: a housing 12; a shaft 16 having a latch bolt 24 at one end and a non-circular key head 28, e.g. oval or polygonal; preferably the shaft is axially slidable and pivotal in the housing between a first locked position and a second unlocked position; a spring bias resists movement of the latch from the locked position; a central pin 32 is located in the shaft having a non-engaging key head. An end 34 of pin preferably abuts a housing in which the lock is installed such that the pin is prevented from movement and obstructs invalid keys which do not have a central recess or hollow centre. The housing 12 may have shoulders either side of a cutout in which the latch bolt is located in the locked position requiring axial sliding of the shaft prior to rotation to the unlocked position. The shaft is preferably hollow having a through hole in which the central pin extends. The lock form part of a keyholder for a manhole cover, the keyholder having separate apertures for insertion of a lifting tool

Description

Lock Assembly The present invention relates to a lock assembly, particularly but not exclusively for use in the locking of street and road covers such as manhole covers and telephone exchange covers, as well as to covers having such a lock assembly or assemblies and key holders therefor.

In streets and roads, and both on and off pavements, there are typically a number of covers adapted to provide access thereunder, such as to services such as for telephones, gas, water, etc., as well as covers for deeper access to underground locations. These are often generally termed manhole covers", but include covers for access under streets, under roads, under pavements or the like.

In such covers, there are usually one or more key holders, often one at each end or each side, intended for the insertion of "keys" designed to lift the cover from its road-or street-aligned position to gain access thereunder.

Typically, the key holders are locked, either directly or indirectly, to prevent unauthoriseci access, and particularly to prevent vandalism, usually by adventurous youngsters. However, such people also seek to undo locks as part of the adventure. Meanwhile, manhole covers are not intended to be complex and costly items, negating the use of sophisticated locking assemblies and mechanisms.

GB2468951A describes a lock assembly with a bolt moveable in a housing between a first locking position and second open position, the bolt having an exposed end having a non-circular key head.

It is an object of the present invention to provide an improved lock assembly, easily able to be used as part of conventional manhole cover manufacture.

According to one aspect of the present invention, there is provided a lock assembly comprising: (a) a lock housing; (b) a shaft moveable in the lock housing between a first locking position and second open position, the shaft having an exposed end, having a key head comprising at least a non-circular key-head portion, and an opposite concealed end; (c) a biaser to bias the shaft in its first locking position; (d) a latch conjoined with the concealed end of the shaft and moveable by the shaft between a first locking position and a second open position; and (e) a pin located in the shaft and having an exposed non-key head.

By having a non-circular key head portion, the shaft, being biased in its locking position, is difficult to turn without the correct key having the corresponding non-circular shape, making it difficult in turn to open the lock assembly and so any conjoined cover, etc. The simple mechanism of this lock assembly can also easily be housed in the spacing provided by or for conventional key holders in conventional covers.

In addition, the pin located in the shaft provides an exposed non-key head, which, by not being operable by a key, negates unauthorised access or vandalism by any contact therewith, while still providing some part of the exposed end of lock assembly.

The lock housing may be in the form of having a regular cross-section, for example being circular, square, etc, and/or having an elongate shape.

Preferably, the lock housing has a first section suitable for partially, wholly or substantially housing the shaft, and also for partially, wholly or substantially accommodating the biaser between part of the lock housing and the shaft.

In one embodiment of the present invention, the lock housing has an outer wall section and at least one traverse section, the biaser being located between the traverse section and a head portion of the shaft having the exposed end.

In another embodiment of the present invention, the lock housing includes a second section able to partially, wholly or substantially house the latch, at least in its first locking position. Preferably, the latch is housed in the lock housing so as not to be moveable to its second open position without the latch being outside the lock housing. That is, the lock housing is able to constrain or confine the latch in a recess or the like and prevent its movement when the latch is in its first locking position.

In another embodiment of the present invention, the latch is moveable between its first locking position and its second open position by movement of the shaft through the lock housing and by rotation of the shalt about the lock housing.

The shaft comprises an exposed end having a key head. The key head may comprise one or more portions, with at least one portion being non-circular, i.e. having any non-circular shape, radially, longitudinally or both.

This includes having a regular or non-regular circumferential shape, and preferably includes at least a circumferential (or cross-sectional) shape being oval, elliptical, polygonal, etc. For example, being generally circular but with a non-constant radius from one or more central points.

Preferably, the non-circular part of the key head should be smooth in at least 2 or 3 dimensions, providing no defined edges, (which could be turned by a sharp tool or object not being the correct corresponding key).

The non-circular key head shape should still provide at least some gripping force around its circumference, such that torque can be applied thereagainst for the movement thereof The key head portion may extend outwardly or inwardly relative to the remainder of the shaft. That is, the key head may have a convex or concave shaped when viewed from above or downwardly along the shaft.

The shaft is moveable between its first and second positions using a key having a corresponding or complementary key-head shape at one end thereof. The corresponding or complementary key-head shape may be recessed into a key body, or extend outwardly from a key body, depending up on the arrangement of the key head on the shaft.

Preferably, the shaft comprises a body having an enlarged head and a central column, the enlarged head including the key head. Also preferably, and top of the exposed end of the shaft is wholly or substantially planer or otherwise aligned with the top of the lock housing when the shaft is in its first locking position.

In one embodiment, the key head of the shaft comprises an inner upstanding ring as the non-circular key head portion, and a lower circumferential shoulder therearound as a second portion. Preferably, the biaser acts against the shoulder.

Preferably, the average width of the inner ring is less than 5mm, more preferably between 1-3mm, and the average width of the shoulder is less than 5mm optionally between 1-3mm.

The pin of the lock assembly of the present invention provides an exposed non-key head, preferably being wholly or substantially planer or otherwise aligned with the top of the lock housing when the shaft is in its first locking position.

Preferably, the exposed non-key head of the pin is also wholly or substantially planer or otherwise aligned with at least a portion of the exposed end of the shaft, more preferably with the top of the non-circular key head portion of the shaft.

Preferably, the exposed non-key head of the pin comprises a central position compared with the exposed end of the shaft, and more preferably in comparison with any inner ring portion of the shaft. Thus, preferably the exposed non-key head of the pin comprises the centre and the central position of the exposed ends of the pin and shaft components of the lock assembly.

Preferably, the shaft is hollow, and the pin is located in the hollow shaft.

More preferably, the pin extends through the hollow shaft and is journalled therethrough.

The pin may have any shape or design. Preferably, the pin is cylindrical, more preferably having an enlarged head and a thinner column.

According to one embodiment of the present invention, the pin extends through the shaft, providing a concealed end opposite the exposed end of the pin. Preferably, the concealed end of the pin extends beyond the shaft, and optionally beyond the end of the shaft and latch conjunction.

More preferably, the concealed end of the pin extends beyond the lock housing, and more preferably extends to the same or a similar depth to any further housing of the lock assembly, such as a key holder comprising one or more of the lock assemblies of the present invention.

The pin provides a part, optionally the majority and br the central part, of the exposed end of the pin and shaft combination, being wholly or substantially planer or otherwise aligned with the top of the lock housing.

However, the pin is also inoperable' in relation to the key and lock mechanism of the lock assembly. That is, action on the pin, in particular the exposed non-key head of the pin, provides no access or unlocking ability of the lock assembly to unauthorised entry.

Where the lock assembly of the present invention is located in a suitable lock housing such as a key holder in a street or road cover, it is preferable that the concealed end of the pin rests or abuts against a solid part of the street or road cover, thereby being non-moveable vertically, or non-moveable along the axis of the opening and locking actions, to further reduce unauthorised play' of the lock assembly by third parties.

In this way, opening of the lock assembly requires the particular interaction of a corresponding key with the non-circular key head portion of the shaft only, and any interaction with the exposed non-key head of the pin serves no purpose.

The biaser may be any suitable device able to provide a biasing force, a non-limiting example being a spring, preferably a helical spring.

Preferably, the biaser biases the shaft against movement from its first locking position.

In another embodiment of the present invention, at least the exposed end of the shaft is wholly or substantially accommodated in the first section of the lock housing in its first locking position. The shaft may wholly or substantially extend along the length of the lock housing, and along the longitudinal axis of the lock housing.

The shaft may be moveable in said first section of the lock housing along the longitudinal axis of the lock housing, and/or move in a rotatable manner about the longitudinal axis of the lock housing, preferably both.

More preferably, the shaft is rotatable within the lock housing and moveable along the longitudinal axis of the lock housing against the biasing force of the biaser to move from its first locking position to its second open position. Movement of the shaft in at least one or possibly both directions is preferably only possible by action of a corresponding key. Indeed, the present invention extends to a lock assembly having a shaft as described herein and moveable in a first longitudinal direction in a lock housing and in a second rotatable direction, against the biasing force of a biaser.

The lock assembly of the present invention is preferably arranged such that the unconnected end of the latch, the distal end, is locatable under or against a suitable, and usually permanent, corresponding frame, unit, device, location, etc., so as to prevent movement of the lock assembly, and therefore any apparatus, device, unit etc attached to the lock assembly, in at least one direction, The suitable unit, etc. may be a latch plate located in, on or otherwise about a frame or frame assembly surrounding the lock assembly and any attached apparatus, etc. One such frame assembly is a frame for a manhole cover.

The lock assembly of the present invention is preferably locatable within the key holder of a cover.

Thus, according to the second aspect of the present invention, there is provided a cover, such as a street or road cover, comprising one or more lock assembles as described herein. Preferably, the cover includes one or more key holders, and the or each lock assembly is located within an associated key holder.

According to another aspect of the present invention, there is provided a key holder for use in a cover comprising one or more lock assemblies as defined herein.

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying diagrammatic drawings in which: Figure 1 is a perspective view of a manhole cover, key holder and lock assembly according to one embodiment of the present invention; Figure 2 is an upper perspecflve view of the key holder and lock assembly of Figure 1 in a first locking position; Figure 3 is lower perspective view of the key holder and lock assembly of Figure 2; Figures 4a and 4b are bottom and part cross-sectional views respectively of the key holder and lock assembly of Figures 2 and 3; Figures 5a, 5b and 5c are side, cross-sectional and plan views respectively of the shaft of the lock assembly of Figure 4b; and Figures 6a, 6b and 6c are side, cross sectional and top views respectively of a key for use with the lock assembly of the present invention.

Referring to the drawings, Figure 1 shows a perspective view of a manhole cover 2. Such manhole covers are well known in the art, and may be used in a street, in a road, on or off a pavement or other passageway, all generally intended for the passage of traffic thereacross, and generally intended to provide access thereunder usually for repair or the like thereunder. Such covers can be made of one or more of the group comprising; concrete, steel, other metals, composites or the like, generally intended to have sufficient robustness to withstand the pressure of traffic thereacross, whilst still being liftable by one or persons when access thereunder is required.

The manhole cover 2 in Figure 1 includes two key holders 4, generally having at least one slot 6, usually an elongate slot, able to accept the end of a lifting means such as a dog-legged lifting bar (not shown), whose free end is insertable and rotatable therein for lifting the manhole cover out of or into its position in a known manner, usually out of or into a surrounding frame (not shown) fixed within the level of the street, road; etc. The key holder 4 is generally formed by a shaped metal enclosure locatable within the manhole cover 2 during manufacture to provide space therewithiri for the entry and rotation of the end of a suitable lifting means.

Next to each slot 6, and within each key holder 4, there is located a lock assembly 10 according to one embodiment of the present invention.

Figure 1 shows the top of the lock housing 12 of the lock assembly 10, and the exposed non-key head 16 of a pin.

Figure 2 shows the key holder 4 outwith the manhole cover 2. The key holder 4 is generally formed of a folded and/or welded piece of metal having an open side' beyond which the distal end of a latch 24 can extend, and therefore extend into or under a latch plate (not shown) or similar, (which could be located within the frame of the cover 2, or otherwise be internally formed in a frame so as to provide space for accommodation of that part of the latch), and t o thereby lock the cover 2 in its usual position over or otherwise protecting a hole or space thereunder in a manner know in the art.

Figure 2 also shows the lock housing 12 having an exposed flange 14 on the top of the key holder 4 and secured thereto.

Figure 2 also shows the exposed end of the shaft, described in more detail hereinafter, and the central exposed non-key head 32 of the pin, also described in more detail hereinafter.

Figure 3 shows a bottom perspective view of the key holder 4, lock assembly 10 and lock housing 12, and more particularly a concealed end 34 of the pin extending below the level of the latch 24.

Figure 4a is a bottom view of the key holder 4 and lock assembly 10 as shown in figures 2 and 3, including the extension of the latch 24 beyond the edge of the lock housing 4. Rotation of the latch 24, generally by a number of degrees, possibly up to 90 degrees, means that its distal end no longer extends beyond the edge of the key holder 4.

Figure 4b is a section BB through figure 4a, showing in particular a cross-sectional view of the lock assembly 10.

In particular, figure 4b shows the look assembly 10 comprising a lock housing 12 located in the key holder 4, generally by its secure fixing into a suitable aperture in the key holder 4, optionally based on the exposed flange 14 and a circumferential recess thereunder.

Within the lock housing 12 is a shaft 16, described in more detail in relation to figures 5a-c, and moveable in the lock housing 12 between a first locking position as shown in figures 2, 3 and 4a, and a second open position (not shown), generally based on rotation of the latch 24 as discussed above.

The shaft 16 has an exposed end 22, part of which is aligned with the top of the lock housing 12, and substantially in alignment with the top face of the key holder 4, and an opposite concealed end 23. The exposed end 22 comprises a key head, comprising a non-circular key head portion 28 and a lower portion 29.

Figure 4b also shows a biaser, being by way of example only a helical spring 26. The helical spring 26 biases an upper end of the shaft 16 away from a platform in the lock housing 12, and hence biases the attached latch 24 in its locking position in a lower section of the shaft 16 and in a slot or recess 13 in the shaft 16, shown more clearly in figure 2.

Figure 4b also shows a pin 30 located in the shaft 16. The pin 30 is generally cylindrical, having an enlarged and exposed non-key head 32 and a thinner column or body therefrom, ending in a concealed end 34 being wholly or substantially in alignment with the bottom plane of the key holder 4 as discussed in more detail hereafter.

Figure 4b also shows the pin 30 being centrally located within the shaft 16.

Figures 5a-c show the shaft 16 in more detail. In particular, they show the shaft 16 having a hollow core, through which the pin 30 can be located.

The exposed head 22 of the shaft 16 comprises an inner ring 28 upstanding from a lower shoulder 29. Against the underside of the shoulder 29 is the surface against which the helical spring 26 exerts its force on the shaft 16.

The inner ring 28 provides a non-circular key head, and figure 5c shows an example wherein the inner ring 28 is an oval being "12.00 X 13.00" in shape. In this way, rotation of the shaft 16 (once the latch 24 is free from the lock housing 12, as discussed hereinafter), is only possible with the use of a particular key having a recess exactly matching the shape of the inner ring 28, and thus matching the non-circular key head portion of the shaft 16. A key having a circular recess would not fit perfectly on or around the inner ring 28, and would not therefore provide any grip or sufficient grip of the sides of the inner ring to allow its rotation, especially when also having to act against the biasing force discussed hereinafter.

The biasing force of the helical spring 26 must also be overcome by a user in order to open the lock assembly 10. Thus1 the user must also exert a downward' force on the lock assembly 10 in order to position the latch 24 outwith the slot 13 at the bottom of the lock housing 12.

Figure 6a-c show various views of a suitable key 40 for use in opening the lock assembly 10, and having a corresponding recess 42, having a non-circular shape corresponding to the non-circular shape of the inner ring 28 of the shaft 16. In the example shown in figures 6a-c, the recess 42 has an oval with dimensions "12.2 X 13.2". The recess 42 creates an end wall 44 of the key 40 having the right height or length able to fit within the space left between the inner ring 28 and the inside of the lock housing 12, and able to act upon the shoulder 29 of the shaft so as to provide the downward force required to counter the biasing force of the helical spring 26, and free the latch 24 from its slot 13 to allow subsequent rotation of the shaft 16.

Both the recess 42 and the end wall 44 must be the correct shape to achieve both downward and rotating actions on the shaft 16. Neither relate to the non-key head end 32 of the pin 30.

Figure 4b shows the concealed end 34 of the pin 30 being wholly or substantially in alignment with the base of the key holder 4. The base of the key holder 4 is generally formed by the material of the manhole cover 2, such as cement, metal, concrete and the like, generally being a heavy material that is able to take the weight that will cross the manhole cover 2.

Because the concealed end 34 of the pin 30 rests or abuts against this solid material of the manhole cover 2, action by an unauthorEsed user on the exposed non-key head end 32 of the pin results in no movement of the pin 30, and certainly no effect upon the lock assembly 10. That is, by having a possibly larger, but clearly central area of the exposed parts of the shaft and pin at the top of the lock assembly 10, action by an unauthorised user on the exposed non-key head 32 has no effect of the lock assembly 101 most especially any unlocking ability.

Overall opening of the lock assembly 10 of the present invention requires providing both a downward force, generally by the circumferential wall 44 of the key 40 on the shoulder 29 of the shaftl6, and rotation of the shaft 16, bythe non-circularmatching ofa recess42 in the key4owith the inner ring 28 at the top of the shaft 16. These dual actions are required to open the lock assembly 10, and the arrangement of the present invention minimises the ability of a non-key holder to achieve both actions simultaneously without the correct key, especially in the constricted space left between the exposed non-key head end 32 and the lock housing inner wall.

Once the key holder has opened both lock assemblies 10 shown in figure 1, the manhole cover 2 can then be lifted out of the way by a suitable lifting bars, etc for authorised access to the area thereunder.

Reverse action of the key 40 in association with the shaft 16 allows realignment of the distal end of the latch 24 conjoined with the shaft 16 back to its locking position in the slot 13 in the lock housing 12, such that the distal end 24 then extends beyond the edge of the lock housing 4, and is locked' in its locking position by the action of the helical spring 26.

It is a preferred feature of the present invention that the dimensions of the inner ring 28 and the shoulder 29, i.e. the dimensions of the exposed end 22 of the shaft 16, are relatively thin or otherwise of less width than the dimensions of the exposed end 32 of the pin 30. Thus, any unauthorised play' of the exposed end 32 of the pin 16 serves no benefit or purpose, significantly reducing the ability of an unauthorised user to use (more commonly available) tools such as screw drivers and the like, to try and open the lock assembly 10.

The present invention provides an improved lock assembly able to be conveniently located within the space of conventional key holders used in conventional covers. The exposed end of the shaft provides a tamperproof head on the locking shaft, which requires a special key to open it. Both longitudinal and rotational movement of the key (on the shaft and hence to the latch) are required to open the lock assembly, without direct action on the centre of the shaft, occupied by the pin, which is preferably static, and indeed non-moveable relative to the shaft in its locked position. With the key head being on the outer part or circumference of the shaft biased towards its locking position, this further increases the tamperproof nature of the present invention by requiring a constant pressure on the shaft by the key during its rotational movement.

Various modifications and variations to the described embodiments of the invention will be apparent to those skilled in the art without departing from the scope of the invention as defined herein. Although the invention has been described in connection with specific preferred embodiments it should be understood that the invention as defined herein should not be unduly limited to such specific embodiments.

Claims (1)

1. <claim-text>Claims 1. A lock assembly comprising: (a) a lock housing; (b) a shaft moveable in the lock housing between a first locking position and second open position, the shaft having an exposed end, having a key head comprising at least a non-circular key-head portion, and an opposite concealed end; (c) a biaser to bias the shaft in its first locking position; (d) a latch conjoined with the concealed end of the shaft and moveable by the shaft between a first locking position and a second open position; and (e) a pin located in the shaft and having an exposed non-key head.</claim-text> <claim-text>2. A lock assembly as claimed in claim I wherein the lock housing has a first section suitable for partially, wholly or substantially housing the shaft, and also for partially, wholly or substantially accommodating the biaser between part of the lock housing and the shaft.</claim-text> <claim-text>3. A lock assembly as claimed in claim I or claim 2 wherein the lock housing has an outer wall section and at least one traverse section, the biaser being located between the traverse section and a head portion of the shaft having the exposed end.</claim-text> <claim-text>4. A lock assemb{y as claimed in any one of the preceding claims wherein the lock housing includes a second section able to partially, wholly or substantially house the latch, at least in its first Cocking position.</claim-text> <claim-text>A lock assembly as claimed in any one of the preceding claims wherein the latch is housed in the lock housing so as not to be moveable to its second open position without the latch being outside the lock housing.</claim-text> <claim-text>6. A lock assembly as claimed in any one of the preceding claims wherein the latch is moveable between its first locking position and its second open position by movement of the shaft through the lock housing and by rotation of the shaft about the lock housing.</claim-text> <claim-text>7. A lock assembly as claimed in any one of the preceding claims wherein the shaft is moveable between its first and second positions using a key having a corresponding or complementary key-head shape at one end thereof.</claim-text> <claim-text>8. A lock assembly as claimed in any one of the preceding claims wherein the shaft comprises a body having an enlarged head and a central column, the enlarged head including the key head. * * . S. S</claim-text> <claim-text>9. A lock assembly as claimed in any one of the preceding claims * .. 20 wherein the top of the exposed end of the shaft is wholly or substantially planer or otheise aligned with the top of the lock housing when the shaft is S..in its first locking position.</claim-text> <claim-text>10. A lock assembly as claimed in any one of the preceding claims wherein the key head of the shaft comprises an inner upstanding ring as the non-circular key head portion, and a lower circumferential shoulder therearound as a second portion.</claim-text> <claim-text>11. A lock assembly as claimed in claim 10 wherein the average width of the inner ring is less than 5mm, preferably between 1-3mm, and the average width of the shoulder is less than 5mm, optionally between 1-3mm.</claim-text> <claim-text>12. A lock assembly as claimed in any one of the preceding claims wherein the pin of the lock assembly provides an exposed non-key head, preferably being wholly or substantially planer or otherwise aligned with the top of the lock housing when the shaft is in its first locking position.</claim-text> <claim-text>13. A lock assembly as claimed in any one of the preceding claims wherein the exposed non-key head of the pin is wholly or substantially planer or otherwise aligned with at least a portion of the exposed end of the shaft, preferably with the top of the non-circular key head portion of the shaft.</claim-text> <claim-text>14. A lock assembly as claimed in any one of the preceding claims wherein the exposed non-key head of the pin comprises a central position compared with the exposed end of the shaft.</claim-text> <claim-text>15. A lock assembly as claimed in any one of the preceding claims wherein the exposed non-key head of the pin comprises the centre and the centraL position of the exposed ends of the pin and shaft components of the 4** lock assembly.</claim-text> <claim-text>* * 20 16. A lock assembly as claimed in any one of the preceding claims wherein the shaft is hollow, and the pin is located in the hollow shaft.</claim-text> <claim-text>17. A lock assembly as claimed in claim 16 wherein the pin extends through the hollow shaft and is journalled therethrough.</claim-text> <claim-text>18. A lock assembly as claimed in any one of the preceding claims wherein the pin extends through the shaft, providing a concealed end opposite the exposed end of the pin.</claim-text> <claim-text>19 A lock assembly as claimed in claim 18 wherein the concealed end of the pin extends beyond the shaft, and optionally beyond the end of the shaft and latch conjunction.</claim-text> <claim-text>20. A Jock assembly as claimed in claim 19 wherein the concealed end of the pin extends beyond the lock housing, and preferably extends to the same or a similar depth to any further housing of the lock assembly.</claim-text> <claim-text>21. A lock assembly as claimed in any one of the preceding claims wherein action bn the pin, in particular the exposed non-key head of the pin, provides no access or unlocking ability of the lock assembly to unauthorised entry.</claim-text> <claim-text>22. A lock assembly as claimed in any one of the preceding claims located in a lock housing such as a key holder in a street or road cover, wherein the concealed end of the pin rests or abuts against a solid part of the street or road cover 23. A lock assembly as claimed in any one of the preceding claims wherein the shaft is rotatable within the lock housing and rnoveable along the longitudinal axis of the lock housing against the biasing force of the biaser to move from its first locking position to its second open position.* *. 20 * * S 24. A Street or road cover comprising one or more lock assembles as * S. defined in any one of claims I to 23.25. A cover as claimed in claim 24 wherein the cover includes one or more key holders, and the or each lock assembly is located within an associated key holder.26. A key holder for use in a cover comprising one or more lock assemblies as defined in any one of claim Ito 23.</claim-text>