The present invention relates to a lock for doors, and in particular to a portable lock which can be applied to a door.

In most buildings only some doors have locks fitted to them. These doors are usually external doors. Often it would be desirable to be able to lock a door that has no lock fitted to it, perhaps on a temporary basis, for example during building work on a building or during a party. Alternatively it might be desired to restrict access to a room or part of a building such that it is only possible to open the door from one side of the door. Locks that perform these functions are known in the art but they generally require fitment to the door by a skilled tradesman. The present invention seeks to provide a lock which can simply be applied to a door without damage or defacement of the door.

According to the present invention there is provided a lock for a door of the type that is opened by turning of a handle connected to a latch, which lock comprises a housing for covering at least part of the handle, and securing means extending from the housing and engageable with an edge of the door for securing the housing to a door with the handle at least partly covered.

The securing means preferably comprises a telescopic arm extending from the housing, which arm having a free end engageable with an edge of the door. Such a telescopic arm preferably comprises means to lock the telescopic arm at a fixed length, said means operable by a key.

Alternatively, the securing means could comprise an adjustable length of cord, belt or web extending from the housing, which cord, belt or web has a free end engageable with an edge of the door.

The housing can be configured to accept a variety of different handle shapes. Preferably the housing comprises a box, said box being configured to enclose a handle in the form of either a knob or a lever. A second possibility comprises a U-section cradle that will engage a handle in the form of a lever. A third possibility comprises a box configured to enclose a handle in the form of a knob.

The housing can incorporate features that prevent the handle from turning, such as a wedging piece. Conversely, the housing can be shaped to allow a handle in the form of a lever to be turned inside the housing.

Engagement means for attaching the lock to the door by engagement with the edge of the door can comprise a U-section clip to engage both sides of the door, thus preventing the removal of the clip while the door is shut.

The invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a lock according to the present invention applied to a door where the lock comprises a U-section housing, a telescopic arm, and a fixed arm. Figure 2A is a perspective view of a lock according to the present invention applied to a door where the lock consists of a U-section housing secured between the handle and the door by means of a cord. Figure 2B is a rear view of an adjusting mechanism of figure 2A. Figure 3A is a side view of a housing in the form of a box with a wedging slot shown fitted to a handle in the form of a knob, Figure 3B is a front view of the housing of figure 3A, Figure 4 is a perspective view of part of a housing for

fitment over a handle either in the form of a lever or in the form of a knob, Figure 5 shows the housing of figure 4 fitted to a handle in the form of a knob, Figure 6 shows the housing of figure 4 fitted to a handle in the form of a lever, Figure 7 shows the housing of figure 4 with a possible cover plate, Figure 8 is a perspective view of a lock according to a preferred embodiment of the present invention applied to a door where the lock comprises a housing in the form of a box secured between the handle and the door by means of a telescopic arm, a fixed arm and a clip. Figure 9 is a partial rear view of a lock according to a preferred embodiment of the present invention, Figure 10 is a partial sectional view through BB of figure

9 of a lock according to a preferred embodiment of the present invention.

Referring to figure 1 there is shown a door 1 with a handle in the form of a lever 2 which operates a latch (not shown) as is common in the art, and a first embodiment of the lock of the present invention which comprises a housing 3 in the form of U-section cradle, a telescopic arm 4a and a fixed arm 4b. The telescopic arm 4a extends from the housing 3, and is slidably mounted over the fixed arm 4b. The fixed arm 4b is engageable with the bottom of the door 1 by means of a clip 5. One design of clip 5 is a U-section that straddles the thickness of the door such that it embraces both sides of the door 1. The telescopic arm 4a and fixed arm 4b can be constructed from any material and cross-section which possess sufficient strength to withstand reasonable force. By way of example the fixed arm 4b could be of solid steel square section, whereas the telescopic arm 4a could be a hollow steel square section with a slightly larger internal dimension than the external dimension of the solid section of fixed arm member 4b.

To apply the lock to the door 1 it is necessary to hook the clip 5 under the door. This can most easily be achieved by opening the door l and sliding the clip 5 underneath the door 1 from the free edge of the door. The telescopic arm 4a can then be slipped over the fixed arm 4b to allow the housing 3 to fit under the lever 2. The door is then closed and the telescopic arm 4a is extended so that the housing 3 is forced against the handle 2 as shown. The telescopic arm 4a can then be locked in position by a locking means 6. The locking means 6 may be key-operated or otherwise as known in the art. The housing 3 prevents turning of the handle 2, thereby ensuring that the door 1 is locked.

Figure 2A shows a second embodiment of the present invention. The lock comprises a housing 3 in the form of a U-section cradle configured to partially cover a lever- type handle 2 of a door 1, a fixed length of cord 104a having two ends, an adjustable cord 104b, a locking mechanism 106 and a clip 5. Cord 104a is attached at one end to the clip 5, and it's second end is attached to the locking mechanism 106. The adjustable cord 104b is attached at one end to the housing 3. The other end of the adjustable cord 104b is passed through the locking mechanism 106 so that the end of the cord can be pulled to adjust the combined effective length of the cords 104a, 104b.

The lock is fitted to the door by firstly fixing the clip to the top of the door. This can be achieved by a U-section clip 5 hooked over top of the door 1, such that when the door 1 is shut the clip 5 cannot be removed from the door 1. The housing 3 is next placed under the handle 2 so that the housing 3 partially covers the handle 2. The length of the cord combination 104a & 104b is then adjusted by pulling the end of the adjustable cord 104b that has been passed through the locking mechanism 106. The length of the adjustable cord 104b is fixed by the locking mechanism 106. The shortening of the cord combination 104a & 104b brings the

housing 3 towards handle 2 and eventually jams the housing 3 against the handle 2. The door l is now locked.

Figure 2B shows a locking mechanism 106 in greater detail than figure 2A. The locking mechanism 106 comprises a pulley block 7 and a self jamming cleat 8. The fixed length of cord 104a is fixed to the top of the locking mechanism, the end of the adjustable cord 104b is passed through the pulley block 7 and the self jamming cleat 8 as shown. However many other locking mechanisms, which are known in the art for securing a cord at a desired length, could alternatively be used.

Referring now to figures 3A and 3B there is shown a housing A for applying to a handle 10 in the form of a knob. The housing A comprises a box 9 with a back 14. The said back

14 has a opening 12 for enabling the handle 10 to enter the box 9. The box 9 has a inclined wedge 11 with a slot 13, said slot having a width less than the maximum diameter of the handle 10. When the housing A is secured between the door 1 and the handle 10 the inclined wedge 11 is jammed against the handle 10 thus preventing the housing A from being removed from the handle 10. The housing A covers the handle 10 such that access to the handle 10 is not permitted. When the housing A is secured between the handle

10 and the door 1, the door 1 is prevented from being opened from the housing A side of the door 1.

Referring now to figures 4, 5, 6 and 7 there is shown a housing 15 for use on handles either of the lever type 2 or of the knob type 10. The housing 15 comprises a top 17, two sides 19 & 20, and a back 26 with a wedge 18 attached to it. The back 26 has two slots 25 capable of accepting a handle in the form of a lever 2; a handle 2 can be inserted through the back 26 and then located in one of the slots 25, depending upon the orientation of the handle 2. Figure 6 shows a handle in the form of a lever 2 located in one of the slots 25.

Similarly to the embodiment described with reference to paragraph 3, the wedge 18 and back 26 of the embodiment of figure 5 have a slot 16 that engages with a handle in the form of a knob 10. The back 26 has an opening 21 with a radius just larger than the radius of the handle in the form of a knob 10 to allow a handle in the form of a knob 10 to be inserted through the back 26. When the housing 15 is applied to a door l with a handle in the form of a knob 10, the handle 10 is inserted through the opening 21 and then engaged with the slot 16 such that the wedge 18 is located against the handle 10. The wedge 18 can be forced against the handle 10 to prevent turning of the handle 10 or, alternatively, the wedge 18 can rest against the handle 10 to allow the door 1 to be opened using a second handle on the other side of the door (not shown) . Figure 5 shows a handle in the form of a knob 10 located in the slot 16 of the wedge 18.

Figure 7 shows a possible cover 24 for the housing 15 to complete the encapsulation of the handle 2, 10 when the housing 15 is applied to the door 1.

Referring now to figures 8, 9 and 10 there is shown a preferred embodiment of a lock according to the present invention. The lock comprises a clip 5 for applying to an edge of the door 1, a telescopic arm 4a, a fixed arm 4b, a locking means 6, and a housing 30. The housing 30 can be fitted to either a handle in the form of a lever 2, or a handle in the form of a knob 10. As in the previous embodiments, the housing 30 is secured about the handle 2,

10 by fitting the housing 30 over the handle 2, 10 and adjusting the telescopic arm 4a relative to the fixed arm 4b with the clip 5 straddling the top (or bottom) of the door. The locking means 6 is then activated to prevent the housing

30 from being removed from the handle 2,10.

As will be appreciated, if the handle 10 is in the form of

a knob, the housing 30 will not prevent rotation of the knob by means of a corresponding knob on the reverse side of the door 1. Hence, the door 1 will be locked to a person approaching the door 1 from the housing 30 side, but can be opened by a person approaching the door 1 from the side of the door 1 opposite to the side carrying the housing 30. Furthermore, the housing 30 is shaped and configured such that a handle in the form of a lever 2 is completely locked if the clip 5 is mounted on the top of the door 1, because the housing 30 physically stops the handle from being turned, but can be opened via a handle on the reverse of the door 1 if the clip 5 engages the bottom of the door 1. In this arrangement, the housing 30 allows the handle 2 to be rotated within the housing 30 by means of a handle 2 on the rear side of the door 1.

As in the embodiment of Figures 4-7, the housing 30 comprises a box with a back 26. The back 26 has two slots 25 for locating a handle 2 or 10, a opening 21 with a radius just larger than the radius of a handle in the form of a knob 10, and a wedging piece 18 to prevent the housing 30 from remaining loose when fitted over the handle 2 or 10. To fit the lock it is first necessary to open the door 1. After fitting the housing 30 over the handle 2 or 10 of the door 1 the telescopic arm 4a is extended to allow the clip 5 to be slipped either over the top of the door 1 (as shown) or under the bottom of the door 1 (not shown) . The telescopic arm 4a is then shortened until the housing 30 and clip 5 are forced against the handle 2, 10 and door 1 respectively, and the telescopic arm 4a is locked at that length by the locking means 6. Subsequently, when the door is closed, it is in a locked configuration.

It will of course be understood that the present invention has been described above purely by way of example, and that modifications in detail can be made within the scope of the invention.