GB2164989A - Blocking devices for keyholes - Google Patents

Abstract

A strip of plastics material is moulded with a thin central transverse part 10 for flexing around a rod or key shaft. Portions 14 taper towards thin distal edges 16. When fully flexed to bring the edges 16 together, the device can be passed into a keyhole aperture. The edges 16 then separate and hinder removal of the device from the keyhole. <IMAGE>

Description

SPECIFICATION Blocking devices for keyholes The invention relates to blocking devices for keyholes in mortice locks in doors and the like, for hindering unlocking and thus entry, and excluding draughts wholly or partly.

A device according to the invention comprises a strip of material having a groove or thin central transverse part for flexing around a rod or key shaft, and portions tapering towards thin distal edges and capable of passing together into a keyhole aperture and separating inside to hinder removal.

The device preferably comprises an auxiliary transverse groove to each side of and parallel to the central groove to provide an alternative recess for a rod or key shaft when the strip is flexed at the central part. The device can be jammed in the keyhole by the insertion of a rod. The rod may be of plastics material, and formed by moulding integral with the strip at one or both ends.

At or adjacent the thick central end of the tapered portions, there are preferably provided further grooves to appear on the outside of the device when flexed. These grooves are to receive a pincer or like tool for the removal of the device from the keyhole.

A special tool would usually be required, and would only be available to those authorized to operate the lock.

The strip of material may be of plastics, nylon, polypropylene or an acrylic compound, made by injection moulding or extrusion for example, or of spring steel or the like, or a combination of two or more thereof.

Drawings Figure 1 is a perspective view of a device according to the invention; and Figure 2 shows alternative arrangements of the device of Figure 1, flexed as when inserted in a keyhole.

With particular reference to Figure 1, the device comprises a strip of nylon moulded with a groove or thin central transverse part 10, and portions 14 tapering towards thin distal edges 16. As shown in Figure 2, the strip is flexed around a rod 18. The rod 18 is of nylon and moulded integral with the adjacent end of the strip. The strip in its fully flexed position as shown in Figure 2 but omitting the rod 18 can be passed into a keyhole aperture where the distal edges 16 separate owing to the resilience of the nylon. The rod 18 can then be inserted to jam the device in position.

Figure 2 also illustrates the alternative use of auxiliary transverse grooves 20 depending on the relative dimensions of the device and of the keyhole.

Further rectilinear grooves 22 appear on the outside of the device to enable its removal from the keyhole by means of a tool such as pliers. Figure 1 shows that the strip is provided with a longitudinal recess 24 at which it may be cut into narrower strips two thirds and one third of the width of the whole for use in shallower keyholes or locks.

1. A blocking device for a keyhole which comprises of material having a groove or thin central transverse part for flexing around a rod or key shaft, and portions tapering towards thin distal edges and capable of passing together into a keyhole aperture and separating inside to hinder removal.

2. A device according to claim 1 which comprises an auxiliary transverse groove to each side of and parallel to the central groove to provide an alternative recess for a rod or key shaft when the strip is flexed at the central part.

3. A device according to claim 1 or claim 2 provided with further grooves at or adjacent the thick central end of the tapered portions to appear on the outside of the device when flexed.

4. A blocking device for a keyhole as herein described with reference to the drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Blocking devices for keyholes The invention relates to blocking devices for keyholes in mortice locks in doors and the like, for hindering unlocking and thus entry, and excluding draughts wholly or partly. A device according to the invention comprises a strip of material having a groove or thin central transverse part for flexing around a rod or key shaft, and portions tapering towards thin distal edges and capable of passing together into a keyhole aperture and separating inside to hinder removal. The device preferably comprises an auxiliary transverse groove to each side of and parallel to the central groove to provide an alternative recess for a rod or key shaft when the strip is flexed at the central part. The device can be jammed in the keyhole by the insertion of a rod. The rod may be of plastics material, and formed by moulding integral with the strip at one or both ends. At or adjacent the thick central end of the tapered portions, there are preferably provided further grooves to appear on the outside of the device when flexed. These grooves are to receive a pincer or like tool for the removal of the device from the keyhole. A special tool would usually be required, and would only be available to those authorized to operate the lock. The strip of material may be of plastics, nylon, polypropylene or an acrylic compound, made by injection moulding or extrusion for example, or of spring steel or the like, or a combination of two or more thereof. Drawings Figure 1 is a perspective view of a device according to the invention; and Figure 2 shows alternative arrangements of the device of Figure 1, flexed as when inserted in a keyhole. With particular reference to Figure 1, the device comprises a strip of nylon moulded with a groove or thin central transverse part 10, and portions 14 tapering towards thin distal edges 16. As shown in Figure 2, the strip is flexed around a rod 18. The rod 18 is of nylon and moulded integral with the adjacent end of the strip. The strip in its fully flexed position as shown in Figure 2 but omitting the rod 18 can be passed into a keyhole aperture where the distal edges 16 separate owing to the resilience of the nylon. The rod 18 can then be inserted to jam the device in position. Figure 2 also illustrates the alternative use of auxiliary transverse grooves 20 depending on the relative dimensions of the device and of the keyhole. Further rectilinear grooves 22 appear on the outside of the device to enable its removal from the keyhole by means of a tool such as pliers. Figure 1 shows that the strip is provided with a longitudinal recess 24 at which it may be cut into narrower strips two thirds and one third of the width of the whole for use in shallower keyholes or locks. CLAIMS

1. A blocking device for a keyhole which comprises of material having a groove or thin central transverse part for flexing around a rod or key shaft, and portions tapering towards thin distal edges and capable of passing together into a keyhole aperture and separating inside to hinder removal.

2. A device according to claim 1 which comprises an auxiliary transverse groove to each side of and parallel to the central groove to provide an alternative recess for a rod or key shaft when the strip is flexed at the central part.

3. A device according to claim 1 or claim 2 provided with further grooves at or adjacent the thick central end of the tapered portions to appear on the outside of the device when flexed.

4. A blocking device for a keyhole as herein described with reference to the drawings.