GB2054724A - Cylinder lock having a flat key - Google Patents

Abstract

A cylinder lock (3) has the slopes (12'') of the ends, of at least some of its individual core pins (12), which cooperate with the associated key (11) different from one another. Correspondingly, the key (11) has individual roots (18) the slopes of at least some of which are different. <IMAGE>

Description

SPECIFICATION Cylinder lock having a flat key The invention relates to a cylinder lock having a cylinder core in which a row of core pins is arranged to be able to slide in drilled holes directed radially of the core. A key channel is arranged along the row of core pins and is connected with the holes drilled for the core pins.

A flat key can be introduced into the key channel, the roots of locking indentations make in its shank acting upon the front end faces of the core pins and by movement of the core pins releasing the cylinder core for turning. The roots of the locking indentations lie inclined at an acute angle to the plane of movement of the core pins. Such a cylinder lock will hereinafter be referred to as "of the kind described".

The acute-angled inclination of the roots of the locking indentations confers the advantage of an additional variable component with respect to the locking combinations to be achieved.

An object of the invention is to develop further a cylinder lock of this type in such a way that the locking combinations are increased.

According to a first aspect of the invention in a cylinder lock of the kind described the slopes of the ends, of at least some of the individual core pins, which cooperate with the key, are different from one another.

The invention also includes a key for a cylinder lock of the kind described the key having individual roots the slopes of at least some of which are different.

With refinements of this kind the number of locking combinations which is achievable is increased. As regards the slope of the roots of the locking indentations or core pin ends very different variations can be achieved. For example, the slopes of ali of the locking indentations or core pin ends may exhibit different angles. Preferably, in that case gradation of the slope is effected by in each case 5 degrees say between 5 and 30 degrees. In this way, for each individual locking indentation or core pin, six possibilities are obtained.

A further increase in the locking combinations can be achieved by the slopes of individual roots or core pin ends being directed in opposite directions from one another. Unauthorized subsequent manufacture of a suitable key to fit a given lock is therefore made very much more difficult. Small deviations as regards the angle of inclination of the roots and the corresponding alignment with the core pins leads to exclusion of the key.

The core pins may have ends tapering to the form of a ridge adapted to the slopes of the roots of the key. Thus the edges of the pin ridges and the roots of the locking indentations must complement one another exactly. Small deviations from one another will prevent turning of the cylinder core. The unturnability of the core pins leads to the situation that they always adopt the correct position with respect to the locking indentations and lead to a troublefree operation of the cylinder lock. The key channel of the cylinder core may further lie parallel with the plane of movement of the pins.

One example of a lock and key according to the invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a cylinder lock having a key inserted, in side elevation; Figure 2 shows, on a larger scale, a crosssection through the cylinder lock and key; Figure 3 shows a core pin in perspective; Figure 4 is a side elevation of the front region of the shank of the key with the profiling of the longitudinal grooves omitted; and, Figure 5 is a section on the line V-V in Figure 4.

The flat key 1 illustrated can be inserted in a cylinder core 3 having a corresponding key channel 2. The cylinder core is seated in a cylinder housing 4 of a symmetrically constructed double locking cylinder. The righthand half 4' of the housing and the lefthand half 4" of the housing are connected together by a bridge 5 of materiai.

In the housing halves 4', 4" holes 6 are provided, drilled in axial alignment, in which the cylinder cores 3 are supported rotatably. Between the two halves 4', 4" of the housing a hub 9 is arranged in a cutout 7 in the cylinder housing 4, carrying the locking tang 8.

The associated flat key 1 consisting of the handle 10 and shank 11 is formed with locking indentations 1 3 on its narrow side adjacent the core pins 12. These are positioned behind one other and form the key notches required in each case for a certain cylinder lock. With the prescribed flat key the core pins 1 2 of the cylinder core 3 are pushed back until their outer ends, which push against coaxially inserted housing pins 15, lie exactly in the gap between the cylinder core and the inner wall of the housing. The housing pins 1 5 are subject to the action of pin strings 1 7 which are inserted in blind holes 1 6 and which force the core pins 12 against the roots 18 of the indentations with the flat key 1 inserted.

The core pins 1 2 are mounted in the cylinder core in such a way as to be unable to turn. For this purpose each core pin 12 is equipped with a crosspin 20 projecting beyond the shell of the core pin and guided in a corresponding part circular groove 21 in the cylinder core 3. Non-turnability of the core pins 12 could also be effected by appropriate cross-sectional profiling, that is, by a non-circular outline of the core pins.

Figures 4 and 5 show that the roots 1 8a, 1 8b, 1 8c and 1 8d have different angles of inclination.

The angles of inclination lie at an acute angle to the plane E-E passing through the shank of the key. It can be seen that the roots 1 8a, 1 8b and 1 8d are all inclined in one direction but have different angles. The root 1 8c on the other hand is inclined in the opposite direction.

The ends of the core pins 12 next to the locking indentations 13 are tapered so as to be ridgeshaped. The slopes 12' of the taper serve in that case for the coordination of the core pins by means of the tip of the key. The edge 12" of the ridge is arranged at the angle of inclination of the associated root 1 8 of the key so that with the correct flat key the core pins 12 are moved so that the plane of separation between the pins 12, 1 5 lies in the gap, to enable turning the cylinder bore 3.

Even a slight deviation in the angle, whether in the roots 1 8 or in the edges 12" of the ridges of the core pins, will prevent turning of the cylinder core.

Claims (10)

1. A cylinder lock of the kind described in which the slopes of the ends, of at least some of the individual core pins, which cooperate with the key are different from one another.

2. A cylinder lock according to claim 1, in which the angles of inclination of the individual core pins are different.

3. A cylinder lock according to claim 1, in which the slopes of at least some of the individual core pins are directed in opposite directions.

4. A cylinder lock according to any of claims 1 to 3, in which the core pins are non-rotatable, the ends of the core pins cooperating with the key being tapered to form a ridge defining the slope of the end of the key.

5. A cylinder lock according to claim 1, substantially as described with reference to Figures 1 to 3 of the accompanying drawings.

6. A key for a cylinder lock of the kind described the key having individual roots the slopes of at least some of which are different.

7. A key according to claim 6, wherein the angles of inclination of the slopes are different.

8. A key according to claim 6, wherein the slopes of the roots are directed in opposite directions.

9. A key according to claim 6, substantially as described with reference to Figures 1, 2, 4 and 5 of the accompanying drawings.

10. A lock according to claim 1 in combination with a key according to claim 6.