[0001] The present invention relates to a cylinder lock of the so-called clutch type which
allows to insert a key from one side even when a key is inserted from the opposite
side.
[0002] A clutch-type cylinder lock comprises a coupling element which provides a rotary
coupling between one plug and the bit regardless of whether a second key is present
or not in the lock on the opposite side with respect to the one in which the key is
inserted.
[0003] Such coupling element has turned out to be difficult to manufacture and to assemble,
since it composed of a plurality of parts, and its assembly can be performed only
with special equipment.
[0004] The aim of the present invention is to provide a cylinder lock of the clutch type,
provided with a coupling element which has a simplified structure which can be assembled
more simply than conventional ones so as to be cheaper to manufacture.
[0005] Within the scope of this aim, an object of the present invention is to provide a
cylinder lock of the so-called clutch type, comprising a case, two coaxial plugs which
can rotate inside said case and are provided with a key slot, pins and complementary
pins which are arranged in said plugs and said case and can be actuated by the key
from a locking position to a position for turning the plugs, a bit which is rotatably
supported between said plugs and can be coupled to said plugs by means of a coupling
element, characterized in that said coupling element comprises two coaxial bushes
which are accommodated in mutually opposite seats of said plugs and are provided with
external teeth by means of which said bushes are rotationally coupled to said plugs
but can slide axially in order to engage an opening of the bit and provide a rotary
coupling therewith, two mushroom-shaped elements having stems which are guided telescopically
one inside the other in contrast with a return spring arranged inside them and the
plates guided in said bushes, said bushes having, in the adjacent ends, walls which
have passage holes for said stems and, at the opposite ends, internal collars which
act as abutment for said plates, springs being arranged between said plates and said
walls and being adapted to actuate said plates against said internal collars, said
collars being provided with recesses which allow the insertion of said mushroom-shaped
elements in said bushes so that said stems pass through said holes and said plates
abut against said collars.
[0006] Further characteristics and advantages of the present invention will become apparent
from the following detailed description of a preferred embodiment of the cylinder
lock according to the present invention, illustrated only by way of non-limitative
example in the accompanying drawings, wherein:
Figure 1 is a longitudinal sectional view of a cylinder lock with the keys removed;
Figure 2 is a view of the lock with one key inserted from one side and arranged on
the central plane of the lock;
Figure 3 is a view of the lock with a key inserted from one side and arranged on the
central plane of the lock and a second key inserted from the opposite side and co-planar
to the first key;
Figure 4 is a view of the lock with a first key inserted from one side and rotated
with respect to the central plane and a second key inserted from the opposite side
and co-planar with respect to the central plane;
Figure 5 is a longitudinal sectional view of the coupling element of the lock of Figures
1-4;
Figures 6 and 7 are views taken in the directions VI-VI and VII-VII of Figure 5; and
finally
Figure 8 is a sectional view, taken along the transverse plane VIII-VIII of Figure
1.
[0007] With reference to the above figures, the reference numeral 1 designates a cylinder
lock which is conventionally composed of two identical parts A and B.
[0008] The following description is given with reference to a single part, and when it is
necessary to distinguish the elements of one pan or the other the corresponding reference
numerals will be accompanied by the letter
a or
b depending on whether the elements belong to part A or pan B, respectively.
[0009] The lock comprises a case which is composed of two tubular bodies 2 which are coaxial
and are connected by a bridge-like elongated body 3 which has, in a median position,
a recess 4 which separates the tubular bodies 2.
[0010] Two plugs 5 can rotate in the tubular bodies 2 and are crossed axially by the slot
6 for inserting the key 7. The reference numerals 8 and 9 designate the holes for
accommodating the pins 10, the complementary pins 11 and the springs 12 which conventionally
form the tumblers for locking the rotation of the plugs when the key is not inserted
or allow its rotation when the key is inserted. The opposite ends of the plugs 5 protrude
into the recess 4. Rings 13 recessed around said ends fix the plugs axially but allow
their rotation.
[0011] The bit 14 of the lock is rotatably mounted on the opposite ends of the plugs 5.
The bit 14 comprises a ring 15 from which there protrudes a radial tab 16 which is
adapted to pass through the recess 4.
[0012] Cylindrical seats 17 are formed in the ring 15 on opposite sides, and the adjacent
ends of the plugs 5 engage therein; said seats are separated by a partition in which
a circular through opening 18 is provided. In the wall that surrounds the opening
18 there is provided a slot 19 (see Figure 8) which is angularly offset with respect
to the central plane P of the lock.
[0013] The opening 18 is aligned with cylindrical seats 20 having an equal diameter which
are formed in the mutually opposite ends of the plugs. The seats 20 also have slots
21 whose cross-section is equal to the cross-section of the slot 19.
[0014] A coupling element, generally designated by the reference numeral 22, is accommodated
in the seats 20 of the plugs 5 and passes through the opening 18.
[0015] The element 22 is formed (see Figure 4) by two cylindrical bushes 23, 23a, 23b which
are as long as, or slightly shorter than, the seats 20 wherein they are guided; the
bushes are externally provided with an axial tooth 24 which slidingly engages in the
slots 21, so that the bushes are rotationally coupled but can move axially in the
seats 20.
[0016] The bushes 23 have walls 25 at their adjacent ends and have internal collars 26 at
their mutually opposite ends; said collars form shoulders 27.
[0017] The bushes 23 accommodate mushroom-shaped elements 28 which are composed of a tubular
stem 29 and a plate 30.
[0018] The tubular stems 29 are guided through holes 31 of the walls 25, whereas the plates
30 are guided from the inside of the bushes 23.
[0019] Springs 32 are interposed between the walls 25 and the plates 30 and keep the plates
30 against the shoulders 27.
[0020] The stems 29 are guided telescopically inside each other, and a spring 33 which is
less rigid than the springs 32 is accommodated inside said stems.
[0021] In order to be able to insert the mushroom-shaped elements 28 in the bushes 23, the
portion of the collars 26 that overlaps the cylindrical wall of the bushes 23 is removed,
so as to form recesses 34 which are open outward.
[0022] The recesses 34 and the holes 31 in the walls 25 have dimensions which are large
enough to ensure the inclined insertion of the stems 29 in the holes 31 and of the
plates 30 inside the bushes, as shown in dashed lines in figure 4.
[0023] When the plates 30 have been inserted in the bushes 23 and straightened inside them,
the springs 32 lock the mushroom-shaped elements, pushing the plates 30 against the
collars 26. Conveniently, the plates 30 have frustum-shaped central portions 35 which
protrude in the opposite direction with respect to the stems and against which, as
will become apparent hereinafter, the tip of the key 7 can act by passing through
the recesses 34.
[0024] The above-described coupling element operates as follows.
[0025] When the key is extracted, the complementary pins 11 are inserted in the holes 8
of the plugs 5 and block their rotation. The recesses 34 are orientated so as to allow
the key 7 to enter the slot 6 and the teeth 24 are angularly offset with respect to
the central plane P (see Figure 8).
[0026] By inserting a key 7a in the slot 6a of the plug 5a, the bush 23a partially engages
the opening 18 of the bit 14, whereas the bush 23b is pushed out of the opening 18
and is inserted in the seat 20b of the plug 5b (see Figure 2).
[0027] In this situation, the plug 5a is rotationally associated by the bush 23a with the
bit 14 by means of the tooth 24a, which is partially inserted in the slot 21a of the
seat 20a and is partially inserted in the slot 19 of the bit. In this situation, since
the bush 23s is completely external to the opening 18, it is possible to turn the
key and therefore the bit.
[0028] If the key 7a is now left inserted in the slot 6a in the position in which the pins
10 are aligned with the complementary pins 11 (i.e., co-planar with respect to the
plane P) and a second key 7b is inserted in the plug 5b (see Figure 3), the thrust
of the key 7b on the plate 30b, since the spring 32b is more rigid than the spring
33, causes the movement of the bush 23b toward the bit and its insertion in the opening
18, thus providing a rotary coupling with the bit by means of the engagement of the
tooth 24b in the slot 19.
[0029] If the key 7a left in the channel 6a is instead turned, i.e., angularly offset with
respect to the plane P (see Figure 4), the opening 18 of the bit cannot be engaged
directly by the bush 23b, because the tooth 24b cannot enter the slot 19. In this
situation, when the key 7b is inserted, the tip of the key produces the axial movement
of the plate 30b within the bush 23b and the compression of the spring 32b, which
accordingly allows to place the contact points of the pins 8 and of the complementary
pins 11 in the plane of the rotation seat of the plug 5b.
[0030] At this point, the key 7b can fully enter the plug 5b and it is possible to turn
the plug 5b until the tooth 24b is aligned with the slot 19. Once alignment has been
achieved, since the spring 32b has been preloaded by the plate 30b, it pushes the
bush 23b into the opening 18, providing a rotary coupling which allows the rotation
of the bit.
[0031] If there is no key in the plug 5a, the insertion of the bush 23b is accompanied by
the simultaneous expulsion of the bush 23a from the bit 14 by means of the spring
33, which keeps the bushes 23a, 23b spaced in the position in which the bush 23a abuts
against the bottom of the seat 20a.
[0032] From the above description it is evident that the fundamental prerogative of the
coupling element 22 resides in that its assembly requires no additional components,
such as elastic rings or the like, which are troublesome to assemble and for which
it is necessary to form seating grooves or shoulders.
[0033] The disclosures in Italian Patent Application No. BO98A000677 from which this application
claims priority are incorporated herein by reference.
[0034] Where technical features mentioned in any claim are followed by reference signs,
those reference signs have been included for the sole purpose of increasing the intelligibility
of the claims and accordingly, such reference signs do not have any limiting effect
on the interpretation of each element identified by way of example by such reference
signs.
1. A cylinder lock of the so-called clutch type, comprising a case, two coaxial plugs
which can rotate inside said case and are provided with a key slot, pins and complementary
pins which are arranged in said plugs and said case and can be actuated by the key
from a locking position to a position for turning the plugs, a bit which is rotatably
supported between said plugs and can be coupled to said plugs by means of a coupling
element, characterized in that said coupling element comprises two coaxial bushes
which are accommodated in mutually opposite seats of said plugs and are provided with
external teeth by means of which said bushes are rotationally coupled to said plugs
but can slide axially in order to engage an opening of the bit and provide a rotary
coupling therewith, two mushroom-shaped elements having stems which are guided telescopically
one inside the other in contrast with a return spring arranged inside them and the
plates guided in said bushes, said bushes having, in the adjacent ends, walls which
have passage holes for said stems and, at the opposite ends, internal collars which
act as abutment for said plates, springs being arranged between said plates and said
walls and being adapted to actuate said plates against said internal collars, said
collars being provided with recesses which allow the insertion of said mushroom-shaped
elements in said bushes so that said stems pass through said holes and said plates
abut against said collars.
2. The lock according to claim 1, characterized in that said recesses are angularly offset
with respect to said teeth.
3. The lock according to claim 1, characterized in that said plates have a frustum-shaped
central portion which is engaged by the key through said recesses.