WO2016179631A1

WO2016179631A1 - Lock and key therefor

Info

Publication number: WO2016179631A1
Application number: PCT/AU2016/000153
Authority: WO
Inventors: George Stephen Ramsay
Original assignee: George Stephen Ramsay
Priority date: 2015-05-14
Filing date: 2016-05-04
Publication date: 2016-11-17

Abstract

A lock cylinder and barrel that will only function and rotate when the correct key is inserted into the barrel aperture. The key will have cuts to match the pin mechanism of the lock cylinder. The key also has a projection or wing that will activate and depress a pivoted arm being part of the barrel assembly that locks into the cylinder housing. The special features of fee key with the wing and the locking arm will provide for two (2) distinct levels of keys and lock cylinders in a series of locks or master key system. Level one, being a special key with a wing that is deemed restricted and only sourceable from the lock system originator following presentation of a written order. Level two, being a standard key without a wing that can be sourced at any key cutting centre or locksmith.

Description

LOCK AND KEY THEREFOR TECHNICAL FIELD

[001] The present invention relates to an improved lock and key for use in the improved lock. In some embodiments, the present invention relates to pin tumbler lock and to a key for use in a pin tumbler lock. The lock of the present mvention has enhanced security features compared to conventional locks,

BACKGEOIWART

[002] Pin tumbler locks are widely used in Australia and in other countries. Pin tumbler locks typically have a cylinder assembly that includes a rotatable core or plug or barrel The cylinder assembly includes a housing into which the core or plug or barrel is positioned. In some locks, such as padlocks, the housing also forms the body of the lock.

[003] The rotatable barrel and the housing have a series of bores formed therein. When the lock is in the locked condition, the bores in the housing are in alignment with the respective bores in the barrel . Each of me aligned bores carries a barrel pin and a housing pin. The barrel pin and the housing pin contact each other at a shear point or a junction point Springs are used to bias the pins towards the barrel. A key slot is formed in the barrel for the key entry. Insertion of a key having the correct notches or bits aligns the shear point of each set of the housing pins and barrel pins with die rotational part of the barrel in the housing. Thus, insertion of the key allows the barrel to rotate in the housing and this allows the locking mechanism to taction. When the key is withdrawn, the shear point between at least one set of housing pins and barrel pins moves so that it is located away from the turning diameter of the barrel litis prevents rotation of the barrel. Similarly, when an incorrect key is inserted, the shear point between at least one set of housing pins and barrel pins is not coincident with the turning diameter of the barrel, thereby prevemting rotation of the barrel.

[004] Pin and tumbler locks may have a plurality of pins, with pin and tumbler locks frequently been provided with five or six sets of barrel and housing pins. However, other numbers of pins may be used. As the number of sets of the barrel and housing pins decreases* the number of possible key combinations that can be set also decreases, thereby reducing security of the lock. Lock manufacturers and locksmiths provide such locks as part of a locking product with two or more key s for the owner of the lock to secure their property , The locks can be supplied as individual units, deemed "keyed to differ" or in lots of two or more in which a single key will open two or more locks, deemed to be "keyed alike "

[005] Lock manufacturers and locksmiths also build and produce a group of locks fa a customer with series of keys to accommodate the specific needs of the owner and this is normally referred to as a system or master key system. A system or master key system can have a series of level s or groups of keys that can operate the mechanism of the various designated locks within the system. For example, in a unit complex having a number of different units occupied by different occupants, each occupant may have a key that only opens the lock to their unit. However, the superintendent of the unit complex may have a master key that opens all of the locks to each unit. In this manner, in emergency situations, emergency services or the superintendent can open the door to each unit This also allows the superintendent to open a specific door in the event that an occupant locks himself or herself out of their unit. A system or master key system can normally be designed and manufactured to suit most types of locks mat the customer requests.

[006] Manufacturers and locksmiths also build lock systems and special cylinders and barrels that have intellectual property protection on the parts of the cylinder, barrels and/or keys. These systems are normally deemed "restricted systems." As mentioned above, the barrel of the lock cylinder is traditionally broached with an aperture that is commonly termed the keyhole or keyslot to accommodate the specific and unique profile shape of the key that is milled with the required specific shape or profile to be identical to the broaching made in the barrel. In this manner the key can be accommodated in the barrel with a precision fit This key shape or design and barrel broaching may also have intellectual property protection.

[007] When a manufacturer or locksmith built a lock system for a customer, that system will normally be assigned a system number and all lock cylinders and keys produced for the system will normally have the system number permanently stamped or marked on each cyiinder and each key. Keys might also be stamped with markings to identify the level of hierarchy or group of locks that key will function within the system. Keys that are part of a restricted system are traditionally stamped with a sequential issue number to provide the system owner with the means for ccratroiling and recording all keys issued to key holders for their restricted locking system.

[008] One particular key profile that is proven to be very popular in the United States and Australians the C4 key profile. Manufacturers of various lock brands and products have realised that it is a key profile that is used and desired by the public and locksmiths for keying other products to the same profile as part of that key system. The C4 key profile has now become the benchmark key profile for most standard lock products produced in five and six pia cylinder format for nonrestricted lock systems for the Australian market

[009] The cuts in the standard key (the valley) that will function the lock cylinder is termed the "bitting " The depth variations of individual bittings in the key is normally about 9 or 10 incremental depths. The depth of individual cuts in the key is designed to match the small precision parts or pin links that are incorporated into the lock system when it is assembled. The possible combination of individual keys for a cottventional standard five pin cylinder lock is in excess of 25,000 and a 6 pin cylinder lock has more than 100,000 possible individual key combinations.

[0010] Australian patent number 666369 in the name of Master Locksmiths Association of Australasia Limited relates to a key actuated pin and tumbler lock having enhanced security. This lock includes a cylindrical core/barrel that is rotatable in a lock housing via a rotational path, a plurality of pin tumblers received in bores in the core/barrel and lock housing, each bore containing a set of pin tumblers comprising one core pin and one housing pin biased towards the core and having a pin junction therebetween and a key slot in the core. The key is provided with suitable bits to enable the pin junctions to align with the rotational path of the core in the lock housing to permit the core to rotate within the housing. The lock also comprises a retaining mechanism in the form of a spring that is biased to engage at least one of the pin tumblers and to resist mo vement of the engaged pin tumbler in either direction in its respective bore until released by insertion of a proper key. In the specific embodiment disclosed in this Australian patent, a spring has a movable end that comes into contact with a cote pin or a housing pin. If a normal key is insetted, the spring remains in contact with the pin and the spring prevents the pin from moving. If a special key having a lateral wing is inserted into the key slot, the wing causes a ball to move and disengage the end of the spring with the pin. This allows the pins to move to the junction point which, in turn, allows the lock to be operated,

[0011] Other types of locks used in Australia include locks that have a number of rotating discs. Each disc has a concave recess formed in it. When a proper key is inserted into the key slot, the discs rotate such that the concave recesses of each disc come into alignment A locking pin can then drop into the aligned recesses to enable actuation of the lock. [0012] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION

[0013] The present invention is directed to a pin and tumbler lock which provides for enhanced secority compared to a conventional pin in tumbler lock.

[0014] With the foregoing in view, the present invention in one form, resides broadly in a lock cylinder having a barrel and a lock housing, the barrel having an arm mounted therein, the arm being biased into contact with the lock housing, the barrel having a key slot for receiving a key, the key including a projection for causing the arm to move out of contact with the lock housing to thereby enable rotation of the barrel in the lock housing,

[0015 ] In another aspect, the present invention provides a lock cylinder having a barrel and a lock housing* the barrel having an arm mounted therein, the arm being biased into contact with the lock housing, the arm being movable between a first position in which the arm is in contact with the lock housing and a second position in which the one end of the arm is spaced from the lock housing.

[0016] The "toek housing" may also be referred to as the "cylinder housing."

[0017] In one embodiment, the arm has one end that is biased into contact with the lock housing, the one end of the aim being movable such that it is withdrawn from contact with the lock housing.

[0018] In one embodiment, the arm is biased outwardly relative to the barrel, the one end of the arm being biased into contact with the lock housing,

[0019] It will be appreciated that the term '"lock cy linder" is used to refer to the combination of the barrel and the lock housing. The lock cylinder does not need to be cylindrieal in shape. Rather, the term "lock cylmder" is a term of the art that refers to the barrel and the lock housing, In some embodiments, such as in padlocks, the lock housing will form part of the external surface of the lock.

[0020] In one embodiment* the lock housing has a recess for receiving the one end of the arm, the barrel having a key slot for receiving a key, the key including a projection for causing the one end of the arm to move out of the recess in the lock housing to thereby enable rotation of the barrel in the lock housing.

[0021] In one embodiment, the lock cylinder is of the pin and tumbler type. The skilled person will appreciate that, in this embodiment, the barrel and the lock housing are provided with aligned bores and that each bore contains a barrel pin and a housing pin, A shear point is located at the junction of the barrel pia and the housing pin in each set of pins. The pins are biased towards the barrel, such as by use of springs . The lock is operated by a key that includes bits that move the housing pin and the locking pin of each set such that the shear point is positioned at the outer diameter of the barrel. When in mis position, in an ordinary pin and tumbler lock, as the shear points for each set of pins is located at the outer diameter of the barrel, the barrel can rotate within the lock housing (if the shear points are located at a different position, one of the housing pin or barrel pia will extend across the junction between the barrel and the lock housing and this will jam the barrel against rotation relative to the lock housing). However, in the lock cyluider of the present invention, it is also necessary to ensure that the one end of the arm be wimdrawn from contact with the lock housing before the barrel cam be rotated relative to the lock housing to thereby operate the lock mechanism.

[0022] In one embodiment, the arm is pivotally mounted in the barrel about a pivot point. The arm has the one end and a second end. When a proper key is inserted, the key includes a surface that moves the secomd end of the arm to thereby cause the first end of the arm to move about the pivot point and to be withdrawn from contact with the barrel Suitably, the one end is withdrawn from the recess in the lock housing.

[0023] The arm may be biased such that the one end of the arm is biased into contact with the lock housing by use of a biasing spring, In other embodiments, -a resilient biasing member, such as a block of rubber or elastomer, may be used to bias the arm. As lock manufacturers and locksmiths are very used to working with small springs, springs are suitably used to bias the arm into contact with the lock housing,

[0024] In some embodiments, a plurality of arms may be provided, each arm betrig biased into contact with the lock housing.

[0025] In one embodiment, the arm is of generally S-shape. [0026] In some embodiments, the biasing member is mounted between the pivot point of the arm and the one end of the area.

[0027] In one embodiment, a slot is formed in the barrel and the arm is mottnted in the slot. The arm may be mounted to a pivot pin extending through an opening in the arm. The pivot pin may .be located in a bore in the barret The pivot pin may be located in a bore that extends in a direction generally parall el to a longitudinal ax is of the barrel This bore suitably extends inwardly from a rear surface of the barrel

[0028] Throughout this specification the term "front of the barrel" is used to denote the end of the barre l where the opening to the key slot can be seen and the term "rear of the barrel" is u sed to denote the end of the barrel that is positioned in the lock housing and not accessible fiora the outside of the lock.

[0029] In some embodiments, the key slot is provided with an opening for receiving a key having a projection with a contact surface for contacting the arm to thereby cause the arm to move out of contact wi th the lock housing. In one embodiment, the key has a laterally extending projection mat comes into contact with the arm to thereby cause the arm to move out of contact with the lock housi ng. The laterally extending projection may be in the form of a wing extending from a side of a shank of the key. In some embodiments, it will be appreciated that the contact surface of the key comes into contact with a drive member that, in turn, drives operation of the arm to drive the arm out of contact with the lock housing_*

[0030] In some embodiments, the barrel is further provided with one or more protection pins. These pins will be inserted into the barrel to protect the arm ironi compromise when a standard key is inserted into the lock barrel In this embodiment, the lock cylinder will include one or more protection pins biased towards the barrel, the lock housing having one or more protection pin recesses for receiving at least part of the protection pins during inserti on of a key, the projection of the key causing the one or more protection pins to extend into the one or more protection pin recesses dining insertion of the key, the projection of the key including one or more recesses that align with the one or more protection pins when the key is rally inserted into the key slot such that the protection pins are biased inwardly towards the barrel and out of the one or more protection pin recesses, the one or more protection pin recesses not preventing rotation of the lock when the key is properly inserted in the key slot.

[0031 ] In this embodiment, it will not be possible to pick the lock by using a standard key having bits that correspond with the pin and tumbler araageinent of the lock and iiisertrog, for example, a piece of wire alongside the key to cause the ami to move out of contact with the lock housing. If this is attempted, the one or more protection pins will be moved outwardly by the piece of wire, thereby causing the one or more protection pins to lock the barrel against rotation relative to the housing, it is only when a proper key is inserted into the lock that the one or more protection pins can move back into the one or more recesses in the contact surface of the key to thereby allow the barrel to rotate relative to the lock housing.

[0032] In some embodiments, the key for actuating the lock cylinder includes bits for moving the sets of barrel pins and housing pins in a first direction and the projection for moving the arm comprises a projection extending in a different direction to the first direction. In one embodiment, the projection for moving the arm comprises a projection extending at right angles to the first direction. In one embodiment, the key moves the sets of pins in a generally vertical direction and the projection extends in and generally horizontal direction.

[0033] The projection of the key may include a contact surface that comes into contact with the arm or with a driving member or a driving mechanism that can drive the arm out of contact with the lock housing. The projection may have one or more recesses located so that the one or more recesses of the projection coincide with the location of any protection pins included in the lock cylinder.

[0034] in embodiments of the present invention, the special profile of the key with the side projection is designed to depress and operate the arm in the barrel so that it moves out of contact with the lock/cyiuider housing and permits the barrel to turn, A lock system can be designed to have a current standard operate somecylinders in the system that do not have the arm installed into the barrel, whilstlhe special profile keys can work most or all cylinders in the system as required. For example, in a unit complex, each unit occupant may be provided with a standard profile key that can operate a front access gate to the unit complex and the fnront door to an occupant's unit. However, there may be other areas to which the occupants of the units are not allowed access, such as an enclosure housing electrical components. The locks used on the enclosure housing electrical components can be in accordance with the present invention and the superintendent (and possibly employees of the electricity supply company) can be provided with special profile keys to enable them to have access to the enclosure_* In this system, it will be appreciated that the key slots of all of the barrels and the system will have openings that enable keys having projections to be inserted therein, even if the particular lock does not include the arm in the barrel In this manner, the special profile key of the superintendent can be inserted into all locks in the system,

[0035] Embedments of the present invention enable the locksmith to produce for the system owner (A) lock products and keys, and that the end user can also source additional products and have those products become an extended part of their own lock system with (B) two or more levels of restricted and unrestricted keys for issue to provide access to their property. A lock system using this product can include locks and keys on a property on level 1 keys, being non- restricted keys where the end user or person can source additional keys without signatory control and other locks on the same property on level 2 keys, being restricted and controlled issue keys for access, that are only available from the originating manufacturer locksmith of the system with a recorded signatory order. The present invention can also provide a system with a mix of lock cylinder/s incorporated into the system that would function on system (B) restricted key s as well as with areas or parts of the sy stem of non-restricted key access, whilst also providing special access to designated locks or areas functioning on the system (A) key.

[0036] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention,

[0037] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge,

BRIEF DESCRIPTION OF DRAWINGS

[0038] Various embodiments of the invention will be described with reference to the following drawings, in which:

[0039] Figure I shows a perspective view of a lock cylinder in accordance with an embodiment of the present invention;

[0040] Figure 2 shows a perspective view of a lock barrel in accordance with one embodiment of the present invention;

[0041] Figure 3 shows a side elevation of the barrel shown in figure 2, showing the spacing and location of the arms mounted in the barrel; [0042] Figure 4 shows a top elevation of the barrel shown in figure 2 showing the standard position of the cylinder pin borings and the special locking arras mounted in the barrel together with the position of the pivot pin for the special locking arms mounted in the barrel;

[0043] Figoie 5 shows a front section of view of the lock cylinder showing the locking arm in a position that is biased into contact with the lock housing; and

[0044] Figure 6 shows a front sectional view of the lock cylinder showing the locking arm being moved to a position at which it is out of contact with the lock housing following insertion of a correctly profiled key.

DESCRIPTION OF EMBODIMENTS

[0045] It will be appreciated that the drawings have been provided for the purposes of illustrating preferred embodiments of the present invention. Therefore, it will be understood that the present invention should not be considered to be limited solely to the features as shown in the attached drawings.

[0046] Figure 1 shows a lock cylinder 10. The lock cylinder 10 includes a lock housing 12. Lock bousing 12 has a bore formed therein and a lock barrel 14 is fitted into the bore in the lock housing 12. A locking mechanism, generally denoted at 16, is actuated by rotation of the barrel 14. The locking mechanism may be of conventional design and need not be described further. The skilled person will appreciate that the locking mechanism operates a latch, a locking bolt or the like which is used to lock a door or a gate, etc. As can be seen from figure 1 , the barrel 14 includes a key slot 18. The key slot 18 has an opening in the front face 19 of the barrel 14.

[0047] The barrel 14 is shown in figure 2, The barrel 14 includes six spaced bores 20, 22, 24, 26, 28, 30. These bores come into alignment with a corresponding series of six bores mat are formedin the lock housing 12. The bores each hold a bore pin 32 and a housing pin 34. A shear junction or shear point 36 exists at the point of contact between the bore pin 32 and the housing pin 34. This is best shown in figure 6. A spring 38 biases the pins 32, 34 inwardly towards the bore 14. This arrangement of bores and pins is conventional in pin and tumbler locks and it need not be described further.

[0048] Figures 3 and 4 show side elevation and top elevation views, respectively, of the barrel. The slots 40, 42 each house an arm 44 (see figures 5 and 6). Arm 44 is of generally S shape. Arm 44 has one end 46 and a second end 48. A pivot pin 50 extends through a bore drilled into the barrel from the rear face 52 of me barrel This is best shown in figure 4. The pivot pin 50 extends through an opening 54 formed in the arm 44. Thus, it will be appreciated that the arm 44 can pivot about the pivot pin 50 extending through opening 54.

[0049] A biasing spring 56 is mounted between an inner wall 58 of the slot 40, 42 and the arm 44. As can be seen from figures 5 and 6, the biasing spring 56 has one end that contacts the inner wall 58 of the slot. The other end 60 is located in or mounted to a depression 62 formed in the ami 44.

[0050] The housing 12 that surrounds the barrel 14 includes a recess 64 that receives the one end 46 of the arm 44, as best shown in figure 5. As can be seen fi¾tn figure 5, the one end 46 of the arm 44 extends into the recess. Attempts to rotate the barrel 14 will result in the end 46 of the arm 44 coming into contact with the respecti ve shoulders formed by the recessed sides of the recess 46, thereby preventing the barrel from rotating. As can be seen in figure 5, when a key 66 having a standard pmfile fe inserted into the key slot, the arm 44 remains in the position shown in figure 5 in which the one end 46 is located in the recess 64 in the lock housing 12. Therefore, the lock cylinder cannot be operated by a key of standard profile, even if the key has appropriate bits to enable the housing pins and bore pins to be moved to a position at which the shear point 36 is located at the j unction between the barrel 14 and the lock housing 12..

[0051] Figure 6 shows the lock barrel 14 having a key 68 of special profile inserted therein. Key 68 has the same bit profile as the key 66 shown in figure 5, which will ensure correct orientation of the housing pins and bore pins to enable the shear point of the pins to be located at the junction between the barrel 14 of the lock housing 12. The key 68 also includes a laterally extending projection 70 in the form of a wing extending sidewap from the shank of the key 68. Upon insertion of the key 68 into the key slot 18, the outer contacting surface of the projection 70 comes into contact with the second end 48 of the arm 44. This pushes the second end 48 of the arm 44 towards the right (in the oriefitation as shown ill figure 6), which causes the arm 44 to rotate in an anticlockwise direction. This causes the arm 44 to move against the force of the bias ing spring 56 and this moves the one end 46 of the arm 44 out of the recess 64 in the lock housing 12. in this miutiner^ the one end 46 of the arm 44 is moved out of contact with the lock housing 12 Consequently, the arm 44 no longer locks the barrel 14 against rotation and the barrel 14 can be rotated to actuate the locking mechanism.

[0052] In order to provide additional security, one or more protecting pins may also be included in the lock cylinder. In this regard, additional bores 72, 74 are formed in the barrel 14. As best shown in figure 3, additional bores 72, 74 are located to the front of respective slots 40, 42. The additional bores 72, 74 each house a protective pin 76 (see figure 6). A biasing spring (not shown) biases the protective pin 76 inwardly towards the barrel As shown in figure 5, the protective pin 76 normaily is seated within the outer diameter of the barrel 14.

[0053] Sti ll with reference to figure 5, the housing 12 is provided with a protective pin recess 78 that is in alignment wim the protective pin 76. If a person seeks unauthorised access to the lock by inserting a normal key and inserting a wire through the key slot at the position at which the projection 70 of the correct key the would normally rest, the wire will force the protective pin 76 outwardly so that an end of the protective pin 76 rests in the protective pin recess 78 in the lock housing 12. Therefore, although the wire may be used to actuate the arm 44 and withdraw the one end 46 of arm 44 out of contact with the housing 12, the protective pin 76 will have been pushed into the protective pin recess 78 by the wire. As a result, the protective pin 76 locks the barrel against rotation relative to the housing. This makes picking the lock very difficult

[0054] hi embodiments where protective pins are provided, the projection 70 of the correct key 68 includes one or more recesses that are positioned such that when the key 68 is fully inserted into the key slot 18, the recesses in the projection 70 house or receive the inner end of the protective pins 76. Thus, the outer ends of the protective pins 76 remain located within the diameter of the barrel (and do not extend into the protective pin recesses 78 in the lock honsing 12). In this position, the protective pins do not prevent rotation of the barrel relative to the lock housing,

[0055] The key 68 may be provided with one or more recesses in the projection 70 in a manner that is simito to that as shown in figure 8 of Australian patent number 666369.

[0056] The lock cylinder of the present invention provides a lock cylinder of enhanced security. The lock cylinder is desirably suitable for use with a C4 key profile having an additional lateral projection or wing extending along a side thereof. In some embodiiments, locking arms may provided on both sides of the key slot and the key maybe provided with projections or wings on both sides of the key shank, The key slot suitably includes an opening that is of complimentary shape to keys haying me desired projections or wings thereon. The lock cylinder may be provided with one or more locking arms. In the embodiment shown in the attached figures, the loefc cylinder is provided with two locking arms.

[0057] Locks cylinders in accordance with the present invention allow lock systems to be implemented in which some locks have lock cylinders in accordance with the present invention and other locks have lock cylinders without the locking arms. In such systems, a supermtendent may have a key with the lateral projection or wing in order to provide master key access to a number of locks. However, an occupant may be provided with a lock that does not have a locking arm and a key that does not include the lateral projection or wing. The occupant's key can operate, for example, the front door of the unit that is equipped with a lock without the locking arms. However, the occupants key cannot operate a secure lock that is fitted with the locking arm, such as a lock fitted to an enclosure housing electrical meters or equipment However, the superintendent will have a key that has the projection or wing and mis enables the superintendent to operate both the lock to the oeeupanfs unit and the lock to the enclosure hous ing electri cal meters or equipment.

[0058] Reference throughout this specification to one embodiment' or 'an embodiment' means that a particular feature, structure, or characteristic described in connection with the

embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases in one embodimenf or 'in an embodiment' in various places throughout this specification are not necessarily all referring to the same embodiment.

Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0059] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect The invention is, therefore, claimed in any of ife forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

Claims

1. A lock cylinder having a barrel and a lock housing, the barrel having an arm mounted therein, the ana being biased into eontaet with the lock housing, the barrel having a key slot for receivmg a key, the key including a projection for causing the arm to move out of contact with the lock housing to thereby enable rotation of the barrel in the lock housing.

2. A lock cylinder having a barrel and a lock housing, the barrel having an arm mounted therein, the arm being biased into contact with the lock housing, the arm being movable between a first position in which tie arm is in contact with the lock housing and a second position in which the one end of the arm is spaced from the lock housing.