Field of invention
The present invention relates to a cylinder lock of the kind defined
in the preamble of Claim 1.
Cylinder locks of the kind that include a profiled element fitted
to the front end of the lock plug have the advantage of enabling the major part
of the key slot formed in the plug to be configured to fit a large number of keys
belonging to one and the same key-family, while separation between various individuals
in the family is achieved by configuring the key slot of the profiled element to
the appearance specific to the individual concerned, i.e. only an intended key
can be inserted.
The profiled element can also be made of any chosen material, which
may be different from the brass material from which the main part of the lock plug
is normally made. For instance, the profiled element may be made of stainless steel
or hardened steel.
The use of hardened steel also incorporates in the lock construction
separate protection against an attempt to drill into the lock, which obviates the
need to provide a separate drill-guard in front of the plug, for instance in the
form of a separate element in the lock construction.
Another advantage afforded by a profiled element of this kind is
that it can be replaced. Thus, when the key-slot opening becomes worn as a result
of very frequent use of the key, it is not necessary to replace the whole of the
cylinder plug or the lock cylinder, since it will normally be sufficient to replace
solely the profiled element.
This replaceability of the profiled element can also be of value
in cases where it is desired to prevent an unauthorized person using a key to which
he/she has access or possesses, for instance after having stolen the key, gaining
entry to a locked room. This can be achieved simply by replacing the profiled
element, without needing to replace the entire lock cylinder.
As before mentioned, cylinder locks that include different types
of profiled element are known to the art.
For instance, SE,B,8403605-2 (Wärtsilä) teaches a lock system that
includes a plurality of different groups of cylinder locks that incorporate rotatable
latch discs and a plurality of different types of key for the various lock groups
with mutually deviating key profiles, wherewith the utility of one key profile
in one lock group is determined by the latch discs of the lock and by the configuration
of the key-receiving opening in the latch discs. One and the same key will have
at least two different profiles disposed axially one after the other. This lock
system can thus be said to include a plurality of profiled elements of the kind
to which this document pertains, arranged one after the other in the lock plug.
These profiled elements are not therefore intended to safeguard the plug from an
attempt to force the lock from outside, for instance by drilling into the plug.
Neither can the profiled element be replaced as readily as that described in the
aforegoing, when the need arises.
US,A,3 736 780 (Singer) describes a cylinder lock in which the profiled
element is attached to the lock plug by means of externally accessible screws.
A separate cover plate may optionally be crimped onto the profiled element, to
enhance the aesthetic appearance of the lock. This arrangement, however, provides
no real protection against forcing of the lock from the outside. The actual cover
plate and the screws can be easily removed with the aid of a screwdriver for instance.
US,A,4 478 061 (Preddey) teaches a cylinder lock according to the
preamble of Claim 1. This lock includes a releasable profiled element that has
a key-slot configured for a key having two parallel coded blades for actuation
of double rows of pin tumblers. The profiled element is anchored to the plug by
means of a cross pin, i.e. a separate member forming no part of the profiled element.
US,A,1 422 594 (Maxwell) describes a cylinder lock in which a profiled
element forms an integral part of the lock plug, said profiled element merely having
a protective function and not intended to separate keys that belong to one and
the same family. The profiled element extends axially beyond the nearest adjacent
pin and forms a substantial part of the circumferential surface of the plug along
substantially the full axial length of the element. The profiled element is secured
to the plug by means of a dovetail joint whose length corresponds to the diameter
of the plug.
US,A,1 422 517 (Augenbraun) describes a cylinder lock with a plug
having a central armor plate with dovetail connection with the front end of the
cylinder and plug, respectively. Attacks on the lock may easily be performed by
means of for instance a chisel.
Objects of the invention
One object of the invention is to provide a cylinder lock of the
aforesaid kind which includes a profiled element and with which forcing of the
plug with the aid of a screwdriver or chisel is much more difficult to achieve
than in earlier cases, and with which the profiled element is securely secured
and can be easily replaced when desired or when necessary, without requiring any
complicated procedures to this end.
Another object of the invention is to provide a cylinder lock that
includes a profiled element of the aforesaid kind and with which the lock cylinder
contributes towards protecting the profiled-element attachment elements so as to
render said elements inaccessible from the outside but to be easily manipulated
when desired, for instance in order to remove or replace the profiled element.
Disclosure of the invention
These objects and other objects are fulfilled by an inventive cylinder
lock having the features set forth in the characterizing clause of Claim 1.
The mutually co-acting engagement surfaces on the profiled element
and on the lock plug respectively may have a relatively large extension, therewith
securing the profiled element to the plug very effectively. These anchoring elements
are also inaccessible from the outside. Because the profiled element and the anchoring
elements can be relatively thick and robust and parts thereof made of a hard material,
for instance hardened steel or stainless steel, it will be understood that attacks
made on the lock with a screwdriver or chisel or with different types of drilling
tools can hardly be successful.
The invention also enables the profiled element to be fitted or mounted
in a simple manner, by moving the element perpendicular to the plug axis after
having removed the plug at least partially from the bore in the lock cylinder.
When the plug is then inserted fully into the bore, the lock cylinder, in which
the bore is formed, contributes towards protecting the engagement surfaces of the
attachment elements from any form of external force.
In one preferred embodiment, the length of the mutually co-acting
engagement surfaces parallel with the direction of the key slot is greater than
the plug radius and is smaller than the plug diameter. In practice, the length
of said surfaces may correspond to 1.6-1.8 times said radius, meaning that the
profiled element will be held securely in place in its use position.
The profiled element and the plug will conveniently have mutually
co-acting engagement surfaces on each side of the key opening in said profiled
element and the key-slot in the plug. In practice, it is preferred that the profiled-element
attachment elements that include the engagement surface or surfaces will have
a generally U-shape, where the engagement surface extends continuously on one side
of the key opening and around said one end thereof.
The engagement surface on the plug will conveniently have a corresponding
U-shape on side of the key-slot in the plug and around one end thereof.
In the case of one embodiment, that part of the plug which includes
said engagement surface or surfaces is located in the front end of a plug-part
that has a larger diameter than the main part of the plug. This embodiment also
contributes to increasing the size of the mutually co-acting engagement surfaces,
particularly when the diameter of the profiled element corresponds to the diameter
of the enlarged part of the plug.
The plug part of larger diameter is suitably accommodated in an enlarged
front part of the plug-receiving bore in the lock cylinder, wherewith the axial
length of said enlarged bore-part corresponds to the combined thickness of the
profiled element and the enlarged plug-part. The front surface of the profiled
element will not project outside the lock cylinder, but will lie in plane therewith,
therewith making any attack on the lock with the use of different types of tool
even more difficult to achieve.
Alternatively, the plug may lack said enlarged end-part and the key
hole in the profiled element be delimited by material therearound.
Further characteristic features of a cylinder lock provided with
a profiled element of the aforesaid kind and advantages afforded by such a lock
will be evident from the following description of preferred embodiments thereof.
The description is given with reference to the accompanying drawings.
Brief description of the drawings
Description of preferred embodiments
- Figure 1 is a perspective view of an inventive cylinder lock provided with
a profiled element and fitted to a door together with a surrounding lock fitting.
- Figure 2 is a perspective view of the plug of a cylinder lock shown in Figure
1, with the profiled element fitted to the plug.
- Figure 3 is an exploded view showing the plug and profiled element of Figure
2 dismantled, wherewith the plug is shown without its associated elements, such
as pin tumblers disposed in the pin holes and the latching rod or bar co-acting
- Figures 4 and 5 are respective front and rear views of the profiled element
that can be fitted to a plug according to Figure 3.
- Figure 6 is a perspective view of a modified version of the Figure 3 embodiment.
- Figure 7 is a perspective view corresponding to Figure 2 and illustrates the
Figure 1 illustrates a cylinder lock 1 and a surrounding fitting
2 mounted in place in a door 3.
The lock cylinder 4 of the cylinder lock 1 has a bore which receives
a plug 7 of the kind shown in Figure 2, said plug 7 being rotatable in the lock-cylinder
bore by means of a key (not shown).
The front part 7b of the plug 7 has a larger diameter than the main
part 7a of the plug and is received in an enlarged front part of the bore in the
lock cylinder 4.
The enlarged front part 7b of the plug includes a key-slot or key-hole
8 which merges with a slot 9 in the main plug-part 7a. In the illustrated embodiment,
the key slot 8 has a comparatively regular profile, whereas the slot 9 may have
an irregular shape so that only a given number of keys belonging to the same key-family
can be inserted into the plug for actuation of the pin tumblers 13 accommodated
in the pin channel 12 therein.
Only one row of pin channels 12 is shown in the drawing. Each of
these pin channels 12 accommodates a pin tumbler 13 adapted for co-action with
a latch rod or latch bar 15 accommodated in a recess 14 in the plug 7. However,
the plug may include in addition to these pin channels or instead of said pin
channels a central row of pin channels (not visible in Figures 2 and 3) that accommodate
bottom pins which co-act typically with top pins (not shown) in the lock cylinder
4, optionally via intermediate pins (not shown either).
Attached in front of the enlarged front-plug part 7b is a profiled
element 5 which is made of a hard material, e.g. stainless steel, and which has
a front surface 5a. The profiled element 5 includes a key hole 6 whose profiled
shape differs somewhat from the profiled shape of the key-slot 9 provided in the
main plug-part 7a, such that only one or a few individuals of the key-family that
can be inserted into the plug 7 will also fit the key hole 6 of the profiled element
In order to enable the profiled element 5 to be fitted securely in
the main plug-part 7a so as to deny access to the profiled element from outside,
the profiled element is provided with attachment elements 5b which, in the illustrated
embodiment - cf Figure 5 for instance - have a general U-shape with one leg of
the U on each side of the key hole 6, said legs being interconnected by an intermediate
part which is taken around one end of the key hole 6.
The engagement surfaces 5b' of these attachment or anchoring elements
5b thus extend beyond one end of the key hole 6 and the key slot 8, 9, respectively,
without reaching to the peripheral surface of the plug located radially outside
the end of the key slot.
The attachment or anchoring elements 5b co-act with corresponding
attachment elements 7c in the enlarged part 7b of the plug 7, more specifically
so that the engagement surfaces 5b' on the profiled-element attachment elements
5b co-act with corresponding engagement surfaces 7c' on the attachment elements
7c in the enlarged plug-part 7b.
It will be seen that the length of the engagement surfaces 5b', 7c'
parallel with the direction of the key slot 6 is greater than the radius of the
plug 7, but smaller than its diameter.
Because the mutually co-acting engagement surfaces 5b' and 7c' have
a comparatively long extension, e.g. about 1.7 times the radius, the profiled element
5 will be held securely and reliably on the plug 7, more specifically so that both
the profiled element 5 and the plug will be inaccessible to an external attack,
e.g. with a screwdriver, chisel or drill.
The lock cylinder 4 therewith contributes towards secure anchorage
of the profiled element 5, since the lock cylinder ensures that no part of the
anchoring elements 5b, 7c and their associated engagement surfaces 5b', 7c' are
accessible from outside the lock.
On the other hand, the profiled element can be removed from the plug
very easily. All that is necessary in this respect is to partially withdraw the
plug from the bore in the lock cylinder 4, so as to enable the profiled element
to be removed in a direction perpendicular to the direction of the plug axis (cf.
Fig. 3), when exchanging the profiled element for another profiled element for
The profiled element is fitted in a corresponding manner, in the
opposite direction, i.e. in a direction perpendicular to the plug axis.
The embodiment shown in Figures 6 and 7 differs from the embodiments
shown in Figures 1-5 in two significant respects.
Firstly, the front plug-part 7'b with the front surface 7'b" has
the same diameter as the remainder of the plug; in other words the part of the
plug provided with the engagement surfaces 7'c is not enlarged in relation to the
main part of the plug.
Secondly, the key hole 6' in the profiled element 5' is completely
surrounded by material, i.e. even in the region of the engagement surfaces 5'b'
on the profiled element. The profiled element 5' thus has greater resistance to
an attack from outside the lock.
It will be understood that these characteristic features of the embodiment
illustrated in Figures 6 and 7 need not both be present at the same time, i.e.
a profiled element 5' whose key hole 6' is totally delimited by material may be
accommodated in a front, enlarged plug-part or, alternatively, a slot-like key
hole in the profiled element, e.g. according to Figures 4 and 5, may be accommodated
in a plug that lacks an enlarged front part.
The attachment or anchoring elements 5b, 5b' of the profiled element
may be designed in a manner different to that illustrated in the associated figures,
provided that reliable and secure anchoring of the profiled element to the plug
can be achieved and provided that the design of said elements falls within the
scope of the following claims.