GB2366595A

GB2366595A - Improved key and lock

Info

Publication number: GB2366595A
Application number: GB0200518A
Authority: GB
Inventors: John Charnley
Original assignee: Yale Security Products UK Ltd
Current assignee: Security Products UK Ltd
Priority date: 2002-01-11
Filing date: 2002-01-11
Publication date: 2002-03-13
Also published as: GB0200518D0

Abstract

In order to compensate for wear to a conventional stop on a key for operating a cylinder or lever lock, a key (13;26) is provided with a first stop surface (18;32), and a second stop surface (21;40) spaced longitudinally from the first stop surface. On full key insertion the first stop surface engages, in use, in the conventional manner, an outer surface of a lock cylinder (12) or a thrower (35), whilst the second stop surface engages a projection (22;39) within the cylinder or thrower. The second stop surface can be defined at the inner end of a cut-out (19) in the end of the key (13), or at the inner end (40) of a groove (33) in one side of a pin section (30) of the key.

Description

2366595 1WROVED KEY AND LOCK This invention relates to a key and lock, and

includes within its scope rim locks, mortice locks and cylinder locks as well as keys therefor.

At present with mortice type lock cases, the keys therefor use the shoulder of the key as both the datum point and the bearing surface, when the key is rotated. Clearance must exist between the key shaft and the key hole. As wear occurs in the key and the key hole, the lock may start to malfunction since the levers are no longer lifted to the correct height. This may result in key breakage. The use of bushes can assist in increasing the usable life span of the lock/key, but these can also reduce actual true differs. In addition, such bus hes, do not retain the key in the centre of the keyway during rotation, nor can they prevent a user from trying to 'pull' or 'push' a key when rotated. When a key is pulled when rotated, the load is taken up by the bitting, resulting in wear, damage or breakage. The consequence of the above-mentioned problem is that a typical mortice key often 'slops' around somewhat in the key hole during operation.

An object of the invention is to at least mitigate this problem.

According to the invention there is provided a key having a bow, a shank, a first stop surface extending laterally from the shank and a second stop surface on the shank spaced from said first stop surface towards a free end of the shank remote from said bow.

Preferably the first stop surface is defined by the junction between the bow and said shank. Alternatively the first stop surface is defined at the junction of a neck, extending from the bow, and said shank. Desirably the second stop surface is an end surface of a cut-away or relieved portion in the underside of the free end of the shank and preferably extending across the width of the shank. Alternatively the second stop surface is an end surface of a groove in one side of a pin section at the end of the shank.

The invention also relates to a blank for such a key, to a lock for use with the key and to the combination of the lock and the key.

The invention will now be described, by way of example, in which:

Figure 1 is a schematic longitudinal cross-sectional view of a key of the invention fitted in a pin-tumbler lock, Figure 2 is a cross-sectional view on line 2-2 of Figure 1 Figure 3 is a side view of another embodiment of a key of the invention, Figure 4 is a cross-sectional view on line 4-4 of Figure 3, Figure 5 is an end view of a lock thrower with which the key of Figure 3 is intended to be used, Figure 6 is a cross-sectional view on line 6-6 of Figure 5, and Figure 7 is a part-sectional, schematic view of the key of Figure 3 fitted in a lock thrower similar to the one shown in Figures 5 and 6.

Figures 1 and 2 schematically show a pin tumbler or cylinder lock 10. As the nature of the conventional parts of such a lock form no part of the present invention, these are not illustrated. However it will be understood that the lock comprises a body or casing 11 having rotatably mounted therein a cylinder or barrel 12 with relative rotation between these two parts being controlled in the normal manner by sprung drivers in bores 11 a in the casing 11 and pins in bores 12a in the cylinder.

Shown engaged in the conventional key slot in the cylinder 12 is a flat cylinder key 13 which is largely of conventional form having a bow 14, a neck 15 extending from the bow, and a shank 16 extending from the neck. The shank is provided in the conventional manner with bitting 17 to raise the pins in the bores 12a so that the drivers become clear of the interface between the cylinder and the casing to allow rotation of the cylinder therein.

As can be seen in Figure 1, when the key 13 is fully inserted into the cylinder 12, a forwardly facing, laterally extending abutment surface 18 at the junction of the neck and the shank engages against the outer face of the cylinder 12 in the normal manner to define a first stop surface on the key. However with the present invention a second stop surface is provided on the key and in the embodiment shown in Figures 1 and 2, this is formed by cutting away the underside of the end of the shank, this cutout being indicated by the numeral 19 in Figure 1. This relieving of the lower end of the shank produces an upper surface 20 extending longitudinally of the shank and lying parallel to the lower flat undersurface of the remainder of the shank. This surface 20 jom's a generally curved surface 21 which extends to the lower flat undersurface of the key shank. As shown best in Figure 2, full insertion of the key 13 brings the curved surface 21 into engagement with a cylindrical cross-bar 22 which extends across the bottom of the cylinder and has its respective opposite ends in aligned bores 23,24 in the casing 11. As shown in Figures 1 and 2, the cylinder has its outer surface formed as an annular recess 25 at the axial position of the cross-bar 22, to allow rotation of the cylinder in the casing despite the presence of the cross-bar 22. However it is to be noted that in an alternative arrangement it will be possible to dispose the cross-bar 22 or equivalent stop to be fast with the cylinder so that it rotates therewith. In practice the fact that with the Figures 1 and 2 embodiment the surface 21 moves out of engagement with the cross-bar 22 when the cylinder is rotated is of no practical consequence in that the insertion depth of the key is fixed, in that the key cannot move by virtue of its engagement with the pins in the bores 14.

Accordingly upon full insertion of the key, as shown in Figure 1, a 'double datum' arrangement is provided so that any wear of the surface 18 will be compensated for by the second stop provided by the surface 21 in engagement with the cross-bar 22. The provision of two depth stops rather than the conventional single stop thus provides an improved key.

The embodiment of the invention shown in Figures 3 to 7 differs from that shown in Figures I and 2 by virtue of the key shown being one for operating a lever lock, either a mortice lock or a rim lock, rather than a pin tumbler lock. However as will be described, this key again has both first and second stop surfaces to provide the advantages referred to with the first embodiment.

Accordingly it can be seen that the key 26 has a bow 27, a shank 28 extending from the bow, the shank at its free end remote from the bow being formed with a conventional radial key bit 29 defining a pin section 30 of the shank. Spaced a short distance from the key bit 29 on the shank is a collar 31 defining an annular first stop surface 32 at the annular shoulder defined between the wider end of the frusto-conical collar and the cylindrical shank which extends to the pin section 30.

Moreover as shown best in Figure 4, it can be seen that at respective opposite sides of t he pin section 30 the outer cylindrical surface is formed with respective grooves 33,34 each groove extending inwards from the respective free end of the pin section 30 of the shank towards the bow 27. As shown in Figure 4, each groove can be of generally rectangular cross-section, although the shape of the groove can be of any suitable form for co-operation with suitable stop means, one embodiment of which will be referred to below.

Figures 5 and 6 show a thrower 35 which is basically in a conventional form well known with lever locks. With such locks the pin key is not borne directly by the casing of the lock as it is turned to shift the levers, but generally by a separate member within the lock which turns with the key and which is itself borne rotationally by the casing. This turning member or thrower engages the bolt to extend or retract the same while the key bit keeps the levers lifted. It is also known that this thrower comprises a curtain member, the purpose of which is to block access through the leg portion of the key hole whenever it is turned away from the key-insertion position, as an an ti-manipulation measure. Figure 5 shows such a curtain 36, and also a rib 37 which, in use, engages in a talon form in the tail of the bolt of the lever lock. This follower defines an internal passageway 38 for reception of the pin section 30 with the key bit 29 extending radially therefrom and as so far described, this thrower is of conventional form. However as shown in Figures 5 and 6, there is provided in the passageway 38, projecting from one side thereof, in a horizontal orientation as viewed in Figure 5, a cylindrical peg 39, this peg extending radially of the circular section part of the passageway 38 as shown in Figure 5. It can also be seen from Figure 5 that this peg terminates short of the vertical centreline through the passageway, and indeed in the embodiment shown terminates at the side of the lower opening in which the flat sided key bit 29 is received.

This peg 39 is received, in use, when the key 26 is fully inserted into the thrower, in one of the grooves 33 or 34 in the pin section 30, depending on which side of the passageway this peg is disposed, assuming insertion of the key into the thrower in the direction shown in Figure 7, i.e. at the end of the thrower remote from the rib 37. Whilst it will be appreciated that the peg 39 shown in Figure 6 would be hidden in the corresponding Figure 7 view showing the key fully inserted in the thrower, for clarity the Figure 7 view is in effect a longitudinal cross- sectional view corresponding to an arrangement where the peg 39 is on the opposite side of the thrower from that shown in Figures 5 and 6. From this view it can be seen that when the key is fully inserted into the thrower, a part-annular end of the thrower is engaged by the first stop surface 32 of the collar 31, whilst the fixed peg 39 past which the groove 33 has travelled during insertion, now engages the complementarily shaped end 40 of groove 33, which end thus forms a second stop surface of the key in the same manner as for ille first and second stop surfaces of the embodiment of Figures I and 2 with, in effect, the cylinder 12 being replaced by the thrower 35 of the lock. Thus once a gain any wear of the first stop surface 32 is compensated for by the provision of the second stop surface forined by the end surface 40 of the groove 33 or groove 34. It will be appreciated that instead of a single projection 39 into the passageway 38, a pair of such projections could be provided for reception in both of the grooves 33,34 respectively.

From the above it will be appreciated that the form of the grooves 33,34 and the corresponding shape of the projection received therein can be of any suitable form.

Claims

1 A key having a bow, a shank, a first -stop surface extending laterally from the shank and a second stop surface on the shank spaced from said first stop surface towards a free end of the shank remote from said bow.

2. A key as claimed in Claim 1, wherein said second stop surface is at an end of a groove or cut-out extending inwardly from said free end of the shank.

3. A key as claimed in Claim 2, wherein said cut-out is defined by a surface extending inwardly from the end of the shank and parallel to a flat longitudinal edge surface thereof, and a further surface defining said end of the cut-out and extending to said outer flat surface.

4. A key as claimed in Claim 3, wherein said surface and said further surface of the cut-out are joined by an arcuate surface.

5. A key as claimed in any one of Claims 2 to 4, wherein the cut-out extends across the whole width of the shank.

6. A key as claimed in Claim 2, wherein said groove is formed in a pin section at an end of the shank remote from the bow, and extends longitudinally of the pin section inwardly from a free end thereof.

7. A key as claimed in Claim 6, wherein the groove is parallel sided.

8. A key as claimed in Claim 6 or Claim 7, wherein said end surface of the groove joining said parallel sides is arcuate.

9. A key as claimed in any one of Claims 6 to 8, wherein said groove is of rectangular transverse cross-section.

10. A key as claimed in any one of Claims 6 to 9, where a pair of said grooves is provided in opposite sides of said pin section respectively.

11. A key as claimed in any one of Claims 3 to 5, wherein said first stop surface is defined by a shoulder at the junction of said shank with a neck portion which is disposed between the shank and the bow.

12. A key as claimed in Claim 11, wherein said shoulder extends laterally outwardly from a longitudinal edge surface of the shank which is bitted.

13. A key as claimed in any one of Claims 6 to 10, wherein said first stop surface is a shoulder at the junction between the shank and a projection thereon ad acent said pin section. i

14. A key as claimed in Claim 13, wherein the shoulder is annular, being at the junction between the shank and a collar forming said projection.

15. A key substantially as hereinbefore described, with reference to, and as shown in Figures 1 and 2, or Figures 3, 4 and 7, of the accompanying drawings.