Patent Publication Number: US-6708539-B1

Title: Lock with removable core

Description:
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/SE00/00129 which has an International filing date of Jan. 21, 2000, which designated the United States of America and was published in English. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cylinder lock with a removable core of the kind comprising: 
     a cylinder lock casing having interior wall surfaces defining an axially extending cavity with an insertion opening, 
     a removable cylinder lock core which is axially insertable into said cavity through said insertion opening, said lock core having an upper, substantially massive part with a row of holes for accommodating locking tumblers, and a lower part defining a cylindrical bore extending axially therethrough, 
     a cylindrical, rotatable key plug located in said cylindrical bore and having a longitudinal key slot for receiving a key co-operating with said locking tumblers, and 
     a retainer member being transversely movable in a chamber in the upper part of said lock core between a first position, in which it positively locks said lock core in its axially inserted position, and a second position, in which said lock core may be axially inserted into or retracted from said casing, said retainer member having a locking surface facing towards said insertion opening and engaging with said casing when said retainer member is in said first position. 
     2. Description of the Background Art 
     Such a lock with a removable core is previously known, e.g., from U.S. Pat. No. 4,328,690 (Medeco) and WO 96/36782 (Winloc). In the prior art locks, the locking surface on the retainer member is formed on an outwardly projecting locking lug, which engages with a recessed portion of the casing so as to retain the lock core in its inserted position. The locking lug can be moved to a second, releasing position where it is instead accommodated in a recess in the massive upper part of the lock core. Then, the whole lock core with the key plug may be retracted axially from the lock casing by a sliding movement. The lock core has an outer contour corresponding to the cross-sectional shape of the cavity of the casing, normally in the general shape of an “8”, with a slight play therebetween to permit the relative sliding movement. 
     With such a system, it is of course possible to replace a lock core of a first kind by another lock core of a second kind, so long as the cross-sectional dimensions of the lock cores are the same and the locking lugs correspond to each other. However, for economic and security reasons, it is in the interest of any lock manufacturer and any authorized user of the system that the lock cores cannot be replaced by other kinds of lock cores, e.g., made by another manufacturer. 
     Furthermore, a locking lug projecting into a recess in the wall of the casing may be destroyed by a machining operation, e.g., by drilling axially into the casing wall from the front side of the lock in the region where the recess and the engaging locking lug are located, normally in the vicinity of the mid-portion of the lock core in case it is formed like an “8”. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     Against this background, the main object of the present invention is to provide a novel embodiment of the locking means holding the lock core in its inserted position in the casing so as to increase the security of the lock. 
     Other objects are to provide high security against unauthorized retraction or replacement of the lock core and to enable rational but controlled manufacture of the lock casings and the associated lock cores and key plugs. 
     The stated main object is achieved in that the lock casing comprises a locking projection, which protrudes from one of the interior wall surfaces so as to project inwardly from said inner cross sectional contour and to engage with the locking surface of the retainer member, when the latter is in the first position, said lock core and said retainer member being adapted to form a longitudinal recess located adjacent to said chamber in the region of said outer cross sectional contour and being dimensioned to accommodate said locking projection when said retainer member is located in said second position and said lock core is being inserted into or retracted from said casing. 
     It is not a trivial matter to arrange such inwardly projecting locking projections, since a locking projection which protrudes inwards from the cavity wall will normally interfere with the contour of the lock core, which matches the inner contour of the casing. However, it is then possible to let the projection fit freely into the above-mentioned longitudinal recess of the lock core. 
     Preferably, the longitudinal recess of the lock core is a rectilinear slot, e.g., extending from one end thereof, and the retainer member is preferably dimensioned to leave said rectilinear slot at least partially free when being situated in said second position, so as to permit axial displacement of said locking projection along said rectilinear slot during insertion or retraction of the lock core, and to effectively block access to said rectilinear slot when being situated in said first position, so as to positively lock said retainer member and said lock core in their axially inserted positions in said cavity of said casing. 
     The present invention also concerns a removable lock core as such and including a retainer member, the lock core and the retainer member being adapted to form a longitudinal recess dimensioned to accommodate, when said retainer member is located in said second position, a locking projection protruding from an interior wall of an associated casing radially inwards from said inner cross sectional contour of the casing. 
     The retainer member may have a limited circumferential extension, which is substantially supplemental to an axially continuous wall portion defining a part of the cylindrical bore, or it may be circumferentially closed so as to form a circular-cylindrical sleeve element, in which case there is an axially extending slot portion in said sleeve element being aligned to the rectilinear slot when the retainer member is located in said second position, an axially limited recess being dimensioned to accommodate the locking projection. 
     The locking surface on the retainer member may be formed on an end surface of a longitudinal edge portion thereof, or on a transversely projecting, axially limited tongue, or on a wall portion defining an axially limited recess. 
     In any case, the removable core can only be replaced by a core of the same kind, i.e. being designed to accommodate the inwardly projecting locking projection while being inserted into the casing. Furthermore, the locking projection is protected by the core itself when the latter is located in its fully inserted position. 
     The locking projection should be long enough to engage with the locking surface on the retainer member. However, the radial extension is preferably limited so as not to interfere directly with the rotatable key plug. Most preferably, the radial extension of the locking projection is such as to reach into close vicinity of the wall surface of said cylindrical bore. 
     In a further developed embodiment according to the invention, the casing has, in addition to the locking projection, an axially limited recessed portion in one of said interior wall surfaces, and the locking means of the retainer member comprises, in addition to an axially limited recess, a locking lug fitting into said recessed portion of the casing when the retainer member is located in said first position. Such a locking lug may be located in close vicinity to said axially limited recess. 
     These and other advantageous features are stated in the dependant claims and will be apparent from the detailed description below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be explained more fully with reference to the accompanying drawings which illustrate some preferred embodiments. 
     FIG. 1 a  shows in a perspective view a cylinder lock casing and a removable cylinder lock core to be inserted into the casing; 
     FIG. 1 b  shows the lock core of FIG. 1 a , wherein the key plug is located in a different rotational position; 
     FIG. 2 illustrates, likewise in a perspective view, the basic parts of the removable cylinder lock core shown in FIG. 1 a , these parts being separated from one another for increased clarity; 
     FIG. 3 is a perspective view of the lock casing of FIG. 1 a;    
     FIG. 4 a  is a perspective view of a retainer member also illustrated in FIG. 2; 
     FIGS. 4 b  and  4   c  illustrate modified embodiments of the retainer member of FIG. 4 a;    
     FIG. 5 is a side view of the lock core also illustrated in FIGS. 1 a  and  2 ; 
     FIG. 6 shows the lock core from the other side; 
     FIG. 7 is a cross-sectional view taken along line VII in FIG. 6; 
     FIG. 8 is a cross-sectional view taken along line VIII in FIG. 6; 
     FIGS. 9-10 and  11 - 12  are end views of the lock core, illustrating the movement of the retainer member from its second, releasing position into its first locking position, and the normal operation of the lock, respectively; 
     FIGS. 13-16 are views corresponding to FIGS. 3,  4  and  2  illustrating some modified embodiments; 
     FIGS. 17-21 are various views illustrating a second embodiment of the lock according to the invention, FIG. 20 being a sectional view taken along the line  20 — 20  in FIG.  18  and FIG. 21 being a sectional view taken along the line  21 — 21  in FIG. 19; 
     FIG. 22 is a view corresponding to FIG. 19, illustrating a modified embodiment; 
     FIGS. 23-27 illustrate another embodiment of the lock casing and the associated lock core; and 
     FIGS. 28-31 illustrate a fourth embodiment included in a door lock assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The first embodiment of the lock according to the invention, shown in FIGS. 1 a  through  12 , comprises a conventional cylinder lock casing  10  having an axially extending cavity  11 , which has a cross-sectional shape essentially like the digit “8” and which is dimensioned for receiving a removable lock core  20  with a rotatable key plug  60  and a key  99 . The casing  10  is intended to be permanently mounted in a door (not shown) or some other object to be locked in relation to a frame or some other stationary structure. Alternatively, the casing  10  may constitute a padlock or some other locking device. 
     The removable cylinder lock core  20  is axially insertable through an insertion opening  13  into the cavity  11  of the casing  10  and is retained in the casing by means of a retainer member  40 , which cooperates with the casing  10 , the lock core  20  and the key plug  60 . The key plug  60  cooperates, at its rear end by means of an axially projecting member (not shown), with a secondary locking mechanism of any kind. 
     In the preferred embodiment, the outer cross-sectional contour of the lock core  20  corresponds exactly to the inner cross-sectional contour of the casing  10 , with a slight play therebetween. Accordingly, the lock core  20  fits slidably in the cavity  11  and is held firmly in its inserted position during normal use of the lock. To this end, there are mutually cooperating locking means at the inside wall of the cavity  11  and at an edge portion of the retainer  40 . According to the invention, the locking means at the casing  10  is constituted by at least one locking projection  12 , which protrudes inwardly from the interior wall  13  defining the cavity  11 . In the preferred embodiment, the projection is located slightly underneath the transition between the upper and lower parts of the cavity, as appears from FIG.  3 . 
     The corresponding locking means on the retainer member  40  is constituted by a locking surface  49 , which faces the insertion opening  13  and is adapted to engage with the locking projection  12 , when the lock core  20  is inserted fully into the cavity  11  and the retainer member  40  is located in a locking position. In the preferred embodiment, shown in FIGS. 2 and 4 a , the locking surface  49  forms a part of a recess  50  located in a longitudinal edge portion  51  of the retainer member. 
     The locking surface  49  may alternatively form an end surface of an edge portion  51 , which is somewhat shorter in the axial direction, as shown in FIG. 4 b , or an end surface of transversely projecting, axially limited tongue  51 ′, as illustrated in FIG. 4 c.    
     In order to enable insertion of the lock core  20 , in spite of the existence of the locking projection  12 , which protrudes into the interior region of the cavity  11  normally occupied by the lock core  20 , the lock core  20  has a longitudinal slot  24  in a lower part  21 , said lower part  21  defining an interior cylindrical bore  23 . The longitudinal slot  24  extends rectilinearly in the axial direction. The slot is dimensioned to accommodate the edge portion  51  (or the tongue  51 ′) of the retainer member  40 , when the latter is moved to its locking position, and to freely accommodate the locking projection  12 , when the retainer member is moved to its releasing position and the lock core  20 , together with the retainer member  40  and the key plug  60 , is being inserted axially into the casing  10 . Then, there is a sufficient circumferential gap  25  (FIG. 1 a ) between the lower edge  26  of the slot  24  and the adjacent edge  52  (FIG. 2) of the retainer member  40 . 
     On the other hand, when the lock core  20  is inserted fully into the casing  10 , and the retainer member  40  is moved transversally, by a rotational movement in the preferred embodiment, into its locking position, as shown in FIG. 1 b , the locking surface  49  will engage with the locking projection  12  and hold the assembled parts in fixed positions relative to each other. Also, in this locking position, the locking projection  12  is effectively protected by the lock core itself. 
     As appears most clearly from FIG. 2, the lock core  20  comprises an upper, massive part  27  and the above-mentioned lower part  21 . In the central vertical plane of the upper part  27 , there is a row of six holes  28  for accommodating upper portions  71  of locking tumblers  70  (including upper portions  71 , mid portions  72  and lower portions  73 ), which are biased in a conventional manner by associated helical springs  74 . The rotatable key plug  60  has a corresponding row of holes  68  which are in registry with the holes  28  in a locking condition. Likewise, there are four corresponding holes  48  in the retainer member for holding the latter in a locking position (as in FIG. 1 a ) by means of the upper tumbler portions  71 . Upon assembly of the various parts of the lock, the key plug  60  will be held axially in place relative to the lock core  20  by means of a locking ring  61 . 
     In the preferred embodiment, the retainer member  40  (see FIGS. 2,  4  and  9 - 12 ) has an axial length of about ⅔ of the lock core  20  and a circumferential extension of somewhat less than 180°. The lower surface  41  of the member  40  is cylindrical with the same curvature as the cylindrical bore  23  of the lock core  20 , so that the bore  23  and the retainer member  40  together form a substantially complete circular-cylindrical housing for the rotatable key plug  60 . 
     The retainer member  40  is rotatable to a limited extent about the central, longitudinal axis of the bore  23  between two end positions, viz. a first position (FIGS. 1 b ,  10 ,  11  and  12 ), in which it positively locks the lock core  20  in its axially inserted position, by mutual engagement between the locking projection  12  of the casing  10  and the locking surface  49  at the edge portion  51  of the retainer member  40 , and a second position (FIGS. 1 a  and  9 ), in which the lock core  20  can be inserted or retracted, by a sliding movement of the locking projection  12  along the gap  25  mentioned above. 
     The retainer member  40  is basically formed as a part-cylindrical shell or a base portion with an upper, central portion  42  being radially extended into a greater, total thickness and being accommodated in a chamber  30  cut out in the upper, massive portion  27  of the lock core  20 . The chamber  30  is defined by an upper slightly curved wall  33 , corresponding essentially to the curvature of the upper surface of the central portion  42  of the retainer member. 
     The cylindrical curvature of the curved wall  33  (and the upper surface of the retainer member  40 ) has a central axis coinciding with the axis of the cylindrical bore  23 , whereby the retainer member  40 , in particular the lower surface  41  thereof, will be supplementary to the lower part  21  of the core  20 , irrespective of the transversal or rotary position of the retainer member  40 . The above mentioned first and second end positions are defined by the abutment of the longitudinal edge  52  against the lower edge  26  of the slot  24  (FIGS. 6 and 10) and the abutment of the opposite edge portion of the retainer member against the associated edge portion of the slot  24  (FIGS.  5  and  9 ). 
     As appears from FIGS. 4 a ,  4   b ,  4   c , the cross-section of the retainer member  40  is substantially the same along the length thereof, except for the axially limited recess  50  or tongue  51 ′, the holes  48  and a number of downwardly directed fingers  45  fitting between upstanding teeth  22  at the lower part  21  of the lock core  20 , adjacent to the slot  24 . The fingers  45  and the teeth  22  will secure a substantially continuous cylindrical bearing surface for the key plug and the tumbler portions  72 ,  73 . 
     If desired, the lock can be provided with two (or more) locking projections  12 , 12 ′ (see FIG. 3) at the inside of the casing  10  and corresponding locking surfaces at axially limited recesses  50 ,  50 ′ at the retainer member  40 . 
     The operation of the lock is illustrated in FIGS. 9-12. In FIG. 9 (see also FIG.  1 ), a control key  99  is inserted into the key slot of the key plug  60  and is turned around to the right, whereby the edge portion  51  of the retainer member is brought away from the edge  26  of the slot  24  so as to leave a longitudinal gap  25 , which makes it possible to insert or retract the lock core  20  in relation to the casing  10  while letting the locking projection  12  slide therealong. When the key  99  is turned to an upright position, as shown in FIG.  10  and FIG. 1 a , the retainer member  40 , the lock core  20  and the key plug  60  are all effectively locked together by means of the locking projection  12  and the locking surface  49 . 
     Now, the lock can be used in the normal way by using an operating key  99 ′, as illustrated in FIGS. 11 and 12. 
     The locking projection  12  should have a limited extension radially inwards so as not to interfere with the rotatable key plug  60 . Preferably, the length of the locking projection  12  is substantially the same as the wall thickness (or slightly less) of the lower part  21  of the lock core  20 . 
     FIGS. 13 through 16 illustrate some modified embodiments of the lock according to the invention. As appears from FIG. 13, it is possible to provide the lock casing  10  with an axially limited recessed portion  14  in addition to the locking projection  12 , e.g., in close vicinity to the latter. As in the embodiment described above, the locking projection  12  engages with a locking surface  49  at an axially limited recess  50  in the retainer member  40 , whereas the recessed portion  14  engages with a first locking lug  46  formed adjacent to the edge portion  51  of the retainer member  40 . 
     Additionally, the retainer member  40  may be provided with a second locking lug in the form of a wing  53 , as described in the above-mentioned document WO 96/36782 (Winloc), which fits into a recess or cut out portion  29  adjoining the slot  24  at  30  the inner end of the latter, i.e. approximately at the axial mid portion of lock core  20  (FIG.  15 ). The wing  53  is partially accommodated in the recessed portion  14  when the retainer member  40  is located in its locking position. As an alternative, or as a supplement, a similar radially outwardly  35  projecting locking wing  53 ′ may be disposed at the rear end of the retainer member  40  (FIG.  14 ). 
     Moreover, as likewise described in the abovementioned document, the lock may be provided with a side-bar  62 , which is movable in a groove  63  in the cylindrical outer surface of the key plug  60  and cooperates with side tumblers (not shown) arranged in the key plug  60 . When located in a locking position, it projects into a longitudinal recess  29  adjoining the cylindrical bore  23  (FIGS.  15  and  16 ). 
     A second embodiment, similar to the lock described in the above-mentioned U.S. Pat. No. 4,328,690, is illustrated in FIGS. 17 through 21. The casing  10 ′ is the same as in the first embodiment (FIGS. 1 a  and  3 ), i.e. with a locking projection  12 . However, the lock core  20 ′ is somewhat different in that it includes two axially separated lower parts  20   a ,  20   b , between which the retainer member  30 ′, with a lower portion formed as a circular-cylindrical sleeve, is rotatably journalled. The rear lower part  20   a  of the lock core  20 ′ has a rectilinear slot  24  and the retainer member  40 ′ has a corresponding slot portion  24 ′ aligned with the slot  24  when the retainer member is located in its releasing position (FIGS. 18 and 20, corresponding to the position shown in FIG. 9 in the first embodiment) upon turning the control key to the right. In this position, the lock core  20 ′ can be inserted into or retracted from the casing  10  while the locking projection  12  slides along the slot  24  and the aligned slot portion  24 ′. 
     When the control key is turned to the left, i.e. into the position shown in FIG. 19, the slot portion  24 ′ is moved into a position being offset from the rectilinear slot  24 , whereas an axially limited recess  50 ″, with a locking surface, captures the locking projection  12  (like a bayonet-type locking groove), so that the lock core  20 ′, the retainer member  40 ′ and the key plug (not shown) are effectively locked in the inserted position inside the lock casing  10 ′. 
     As an alternative, see FIG. 22, there may be an aligned slot portion  24 ″ also in the front lower part  20   b , having a length slightly exceeding the longitudinal dimension of the locking projection  12 . Upon inserting the lock core  20 ′ axially into the casing  10 ′, the locking projection  12  will be located in the slot portion  24 ″ (as illustrated). Then the retainer member  40 ′ is rotated into its locking position where the slot portion  24 ′ (shown by dashed lines) is offset from the slot portions  24 ,  24 ″ of the rear and front lower parts  20   a ,  20   b  of the lock core  20 ′. 
     Of course, the slot portions  24 ,  24 ′,  24 ″ shown in FIGS. 17-22 may have the form of a groove with a bottom surface rather than a through-going slot, provided that the locking projection is shorter than the depth of the groove. 
     A third embodiment is shown in FIGS. 23 through 27. The front part  10 ″ a  of the lock casing  10 ″ is just like the embodiment of FIG. 1 a , with a cavity  11 ″ having a cross-sectional contour like an “8” and a locking projection  12  protruding inwards as shown in FIG. 25, whereas the rear part  10 ″ b  of the lock casing  10 ″ has a different, more narrow contour with a rectangular upper part  11 ″ a  (FIG.  26 ). The latter accommodates a corresponding rectangular upper portion  20 ′ a  of the rear part of the lock core  20 ″, see also FIGS. 24 and 27. 
     Thus, the inner contour of the casing  10 ″ and the outer contour of the lock core  20 ″ vary in the longitudinal direction, but these contours are supplementary to each other along the whole length of the lock. In this embodiment, the retainer member (not shown) may be formed substantially like the retainer member shown in FIG. 4 a , although provided with an upper wing (similar to the wing  53  in FIG. 14) fitting into the cut-out portion or recess  29 ″ of the lock core  20 ″ (FIG.  24 ). 
     In a fourth embodiment, the lock is a part of a door lock assembly as shown in FIGS. 28-31, including a rear casing  100   r  to be mounted at the inside of a door (not shown), and a front casing  100  to be mounted at the front side of the door. A lock core  120  (see FIGS. 29 and 31) is similar to the core  20  of FIG. 2 but has two concavely curved recesses  121 ,  122  dimensioned to receive two radial lugs  101 ,  102  at the rear end portion of the casing  100  when being inserted into the casing  100 . As appears from FIG. 28, screws  1 ,  2  are inserted through holes  101   h ,  102   h  and are used to secure the casings  100 ,  100   r  to the door. 
     At the rear end of the casing  100 , a rotatable locking member  104  is rotatably journalled in a circular opening  105  in the rear wall  106  of the casing. The rotatable member  104  has an axial, relatively long rod  107  and an axial, relatively short rod  108  extending into the internal cavity of the casing and into an axial hole  161  and a diametrical groove  162 , respectively, at the end portion of the key plug  160  of the lock core (only shown in FIG.  31 ). In this way the rotary movement of the key plug is transferred to the locking member  104 . 
     In order to make sure that only lock cores  120  of the same kind are insertable into the casing  100 , the axial hole  161  is very wide, about 4 to 5 mm, (the key plug has a diameter of 12 to 14 mm, preferably about 13 mm), and the smallest wall thickness between the circumferential surface of the key plug  160  and the axial hole  161  is about 0.5 mm. The diameter or width of the axial rod  107  is slightly smaller than that of the hole, preferably 3.7 to 4.5 mm. The cross-sectional shape of the rod  107  and the hole  161  does not have to be circular but could be of any suitable shape, e.g. rectangular or triangular. 
     Furthermore, the locking projection  112  extends radially inwards through the longitudinal slot  124  of the lock core  120  (FIG. 29) to a position being very close to the circumferential surface of the key plug (when the lock core with the key plug is inserted into the casing). In any case, the radial distance between the locking projection  112  and said circumferential surface should not exceed 1 mm. Preferably, the distance is much less. Thus, the radial distance between the locking projection  112  and the rotary axis (coinciding with the centre of the opening  105 , FIG. 30) of the key plug  160  should be no more than 1 mm greater than the radial distance between the radially outermost part of the axial rod  107  and the rotary axis. 
     By the combination of the locking projection  112  and the axial rod  107  extending into the cavity of the casing  100 , it will be practically impossible to replace the lock core  120  by another kind of lock core, not even a smaller one. Such a smaller lock core may be narrow enough to be inserted freely passed the projection  112 . However, in a smaller lock core, it will be impossible to make a wide enough axial hole in the rear part of the key plug without breaking through the circumferential surface or the central key slot thereof. 
     Hereby, any unauthorized replacement of the lock core will be hindered effectively.