US3541820A

US3541820A - Breechlock core and knob

Info

Publication number: US3541820A
Authority: US
Inventors: Walter E Best
Original assignee: Best Lock Corp
Current assignee: Stanley Security Solutions Inc
Priority date: 1969-04-18
Filing date: 1969-04-18
Publication date: 1970-11-24
Anticipated expiration: 1987-11-24

Description

W. E. BEST BREECHLOCK CORE AND KNOB Nov. 24, 1970 2 Sheets-Sheet 1 Filed April 18, 1969 Fig. 1

sea 2 "Ill INVENTOR Nov. 24, 1970 w. 5, BEST 3,541,820

BREECHLOCK CORE AND KNOB Filed April 18, 1969 2 Sheets-Sheet 2 24 v QINVENTOR United States Patent 3,541,820 BREECHLOCK CORE AND KNOB Walter E. Best, Indianapolis, Ind., assignor to Best Lock Corporation, Indianapolis, Ind., a corporation of Indiana Filed Apr. 18, 1969, Ser. No. 817,362 Int. Cl. Eb 35/00 US. Cl. 70369 21 Claims ABSTRACT OF THE DISCLOSURE A key-removable, front breech mounted, pin tumbler look. A front breech plate is rotatively positioned by a short control sleeve on the front of a key plug in a core body. A pin barrel web of the core body overlies the sleeve. Pins in the front pin barrel normally hold the sleeve in breech locking position. A control key actuates such pins to release the sleeve and pin it to the key plug for turning to breech-released position. An operating key actuates all pins for normal key plug turning with the sleeve locked to the core body in breech-locking position.

The core fits a front mounting wall, as in a knob. It may also engage a rear knob portion for rotative positioning. The breech plate and mounting wall opening are each diametrically symmetrical to permit the core to be mounted right-side up with the knob in either of two 180 positions on opposite sides of the door.

This invention relates to a pin tumbler lock core having a front breech mounting, and to a knob structure embodying such core.

The invention provides a pin tumbler lock core having a front breech mounting, which is inexpensive to manufacture and assemble, and is adapted for use in residential exterior doors and in low cost applications requiring a high degree of security, and combines such core with a knob structure wherein the parts of the knob and core are all formed of relatively inexpensive screw machine parts or stampings. The breech shape provides reversible balanced mounting.

In accordance with the invention, the core body has a cylindrical portion bored to receive the key plug, and a longitudinal web drilled radially to form pin tumbler barrels. Such body may be cut to length from brass extrusion stock. The front portion of the body is cut away to remove a short length of the cylindrical portion, and this is replaced by a short control sleeve which surrounds the front portion of the key plug and lies across the front pin tumbler barrel, or across more than one of the front pin tumbler barrels. The sleeve provides an operating shear line between its inner face and the key plug and a control shear line between its outer face and the pinbarrel web. A breech plate mounted on the front of the key plug, is rotatably controlled by the sleeve for movement of say between a breech locking position and a release position. A face plate is mounted with the breech plate behind a front retaining flange of the key plug. The assembly is held together and the key plug retained in the core body by a key stop fixed to the rear of the plug. A throw member connects the key plug to a spindle for operating a bolt or other secondary lock, and the connection permits 15 of free rotation of the key plug to move the breech plate between engaged and disengaged positions. The core is adapted to be mounted in a breech opening in a mounting wall, especially a wall at the front of a door knob.

Breech-plate operation is key controlled. The tumbler pins in the front barrel normally pin the sleeve to the body in breech-locking position. A control key actuates the front pin stack to align a pin separation face with the 3,541,820 Patented Nov. 24, 1970 operating shear line between the sleeve and body, and actuates the other pin stacks to align separation faces with the operating shear line. The plug will then turn the sleeve and breech plate. An operating key actuates all pin stacks to align separation faces in the operating shear line and leaves the sleeve and breech plate locked in engaged position. The separation face or faces in the front pin stack are desirably so located that the control key cut in the front pin stack position is higher than the corresponding cut in the operating key.

The operation of inserting a key removal core is first to rotate the key plug, sleeve and breech plate 15 with a control key, then to insert the core through the breech opening in the mounting wall, and then to return the key plug to its normal key removal position.

The breech mounting desirably permits installation in either of two positions apart. To this end, the breech opening includes diametrically opposite slots to pass the pin barrel web of the core body, and the configuration of the breech plate and mounting plate opening are symmetrical with respect to such two positions. This permits the core to be inserted upright with the knob reversed for right or left handed doors.

The knob comprises an outer shell which is swaged over an inner shell that forms a rear wall and a mounting stem for the knob, and the relationship is such that the rear of the pin barrel web on the core body engages a notch in such rear wall to retain the core body and knob parts against relative rotation.

The accompanying drawings illustrate the invention. In such drawings:

FIG. 1 is a longitudinal section of a lock knob structure containing a key removable core in accordance with the invention;

FIG. 2 is a section on a line 22 of FIG. 1;

FIG. 3 is a section on a line 33 of FIG. 1;

FIG. 4 is a section on a line 44 of FIG. 1;

FIG. 5 is an isometric exploded view of the lock spindle, throw member and key plug; a

FIG. 6 shows a modification of FIG. 2; and

FIGS. 7 and 8 are respectively a front elevation and a section of a modified breech plate.

The embodiment shown in FIGS. 1 to 5 comprises a knob 10 with a lock core 12 mounted in its front face. The knob shown is of tulipshape and is made of formed sheet metal parts. The knob comprises a dra'wn inner shell 14 having a frusto-conical side wall 16 which merges at the rear into a back wall 18, and this in turn merges into a cylindrical mounting sleeve 20. The mounting sleeve 20 is received on an inner cam sleeve 22 of tubular shape formed by rolling a heavy stock strip into a cylinder. The cam sleeve 22 is rotatably mounted in the secondary lock mechanism to control the lock bolt, in any conventional or known manner. The front end of the cam sleeve 22 is transversely slotted to provide diametrically opposite slots 24 for the reception of the pin barrel web of the core body 12. The rear wall 18 of the inner shell 14 is punched to form slots 26 to receive the rear portion of the pin barrel web and to be thereby interlocked to rotate with the cam sleeve.

The inner shell 14 is covered by a drawn and swaged outer shell 28 having a front face 30 and a side wall 32, the side wall 32 being swaged down over the frustoconical side wall 16 of the inner shell and flanged inward over the curved section joining such side wall 16 with the back wall 18. The knob is finished at the rear by a ferrule or cover ring 34 mounted on the sleeve 20 and extending into a trim ring 36 on the knob mounting.

The front face 30 of the knob face slopes inward and is formed with a central recess defined by a drawn section 38 and a bottom mounting wall 40. Such mounting wall 40 is punched to form a breech opening 42 as shown in FIG. 2 for the reception of a breech plate 44 carried by the core body 12 for mounting such core body in the knob. The breech opening may have any suitable breechlock configuration. The preferred configuration shown in FIG. 2 comprises two symmetrical halves. At the top and bottom, the breech opening includes a deep notch 46 of a size to closely receive the pin barrel web of the core body 12. Proceeding clockwise from each such notch, the breech opening defines first an inward tongue 48, then a notch 50, then an inward tongue 52, then a notch 54, then a tongue 56, and then a wide notch 58 which merges with and joins the opposite web-receiving notch 46. Since each element recited has a similar element diametrically opposite it, the breech opening is diametrically symmetrical, to permit the lock core to be mounted in either of two 180 positions, and hence right side up in any mounting of the knob. The breech plate 44 has the same configuration as the breech opening except for the webreceiving slots 46, and thus has

tongues

51, 55, and 57 complementary to the

slots

50, 54, and 58, respectively, of the breech opening. Between each pair of

tongues

51 and 57, the breech plate has a wide notch to receive both the core body web 62 and the mounting-plate tongue 48.

As shown in FIGS. 1 and 3, the lock core body 12 comprises a lower cylinder 60 and an upper web 62. The cylinder 60 contains or is bored to contain a cylindrical axial opening for the reception of the key plug 64, and the web 62 and plug 64 are bored radially to form pin barrels 66. Such pin barrels intersect the key slot which is broached longitudinally through the key plug 64. The key plug also contains a pair of drilled holes 72 for the reception of the legs of a throw member described below.

The core body 12 is conveniently made by cutting suitable lengths from a brass extrusion having the cross section of the core body 12. The front end of the corebody blank is cut away, as on a screw machine, to remove a front portion of its cylinder 60 and permit that portion to be replaced by a breech control sleeve 74 shown in FIGS. 1 and 2, and to leave a web portion overlying the sleeve and containing the front pin barrel 66a. The machining also cuts away an inner part of the front of the web 62 to provide clearance for the breech plate 44, and to leave an overhanging front nose portion 76 defined at its inner periphery by an arc of the same radius as the inner end of the tongue 48 defined by the breech opening 42. When the lock core 12 is mounted in the mounting wall 40 of the knob 28, such forward nose portion 76 lies in a notch 46 of the breech opening, and hence locks the core body against rotation in the mounting wall 40'.

As previously noted, the rear end 77 of the pin barrel web 62 engages in a slot 26 in the inner shell 14 of the knob to further interlock the parts against relative rotation.

The key plug 64 is rotatably mounted in the bore of the core body cylinder 60. Such plug has a front retaining flange 78, behind which is mounted a circular face plate 80 and the breech plate 44. The face plate 80 fits within the drawn section 38 of the knob face and fills the central recess of the knob. Its inner periphery closely surrounds the cylindrical body of the key plug 64 immediately behind the flange 78. The breech plate 44 is mounted immediately behind the face plate 80. The inner periphery of the breech plate comprises two circular portions 82 of a size to fit over the breech control sleeve 74, separated by two inwardly extending splines 84 which engage in diametrically opposite slots 86 at the front of the sleeve 74. The breech plate 44 is thus carried and rotatively positioned by the sleeve 74 on the outer circumference of the key plug 64. The plate and sleeve are axially positioned between the facing ring 80 and the front face of the cylinder 60 of the core body.

The key plug 64 extends rearward through the core body 12. A key-stop is secured by rivets 88 to the rear end of the plug and bears against the rear face of the body to hold the plug axially in the body. As shown 4 in FIG. 5, the key stop 90 contains rivet holes 89 and openings 91 and 92 to pass the nose of the key and the legs of the throw member.

The throw member 94 shown in FIGS. 1, 4 and 5 is a formed sheet metal element having a pair of forwardly extending legs 96 for engagement in the key plug 64 and key stop 90, and these are connected by a downwardly offset portion 98 to a rear circular plate 100 having a central opening 102 for the reception of a spindle 104 by which key rotation of the plug 64 is transmitted to the secondary lock structure. As shown in FIG. 4, the opening 102 in the rear plate 100 of the throw member 94 is a circular opening interrupted by diametrically opposite inwardly projecting lugs 103. The spindle has diametrically opposite ribs 105 for engagement with such lugs 103 to transmit movement of the throw member to the spindle. The lugs 103 are normally spaced from the ribs 105 by an angle of 15 to provide limited lost motion between the throw member and the spindle, and thereby to permit limited rotation of the key plug 64 for purposes of engaging and disengaging the breech plate 44 from the mounting plate 40.

The several pin barrels in the core body and key plug 64 contain stacks of tumbler pins 106 spring pressed inward by springs 108 retained by caps 110. In each stack, the pins abut at a face 112 at which shear separation may occur. A lock operating shear line 114 is defiined at the circumferential surface of the key plug 64, between such key plug and the surrounding inner periphery of the core body 12 and the breech control sleeve 74. A control shear line 116 is defined between the outer periphery of the breech control sleeve 74 and the overlying face of the pin barrel web 62 of the core body 12.

In the absence of a key, the separtion faces 112 of the pins lie out of alignment with the two shear lines, and the key plug 64 and the breech control sleeve 74 are locked against rotation in the core body 12. An operating key in the key way 78 will lift each pin stack to bring its separation face 112 into alignment with the operating shear line 114, and this will permit the key plug 64 to be turned in the usual manner for key operation of the lock. During such operation, the pin stack 106a in the front pin barrel 66a will extend across the control shear line 116 to lock the breech control sleeve 74 to the core body 12 and thereby prevent rotation of such sleeve 74 and the breech plate 44 controlled by such sleeve.

For operation of the breech mounting for the core body 12, a special control key 124 is inserted in the key way 78. It is like the operating key except that it has a higher cut at the front tumbler pin position, which raises the front tumbler pin stack 106a to align its shear separation face 112 with the control shear line 116 at the outer periphery of the breech control sleeve 74, and to position its inner pin across the operating shear line 114 to lock the breech control sleeve 74 to the key plug 64. The control key 124 may then be turned through a short angle suflicient to operate the breech plate 44.

The extreme position to which the breech plate 44 may be turned (clockwise) by the key plug 64 and the breech control sleeve 74, is shown in FIG. 2. In that position, the

lugs

51, 55 and 57 of the breech plate 44 will be aligned with the

notches

50, 54 and 58 of the breech plate opening 42 in the mounting wall 40. Hence, the entire core assembly, including the core body 12, the breech plate 44, the face plate 80 and the key plug 64, is then free to be moved axially into or out of its mounting in the knob 10. To mount such a core assembly in the knob, the core assembly is inserted axially through the breech opening 42 until the face plate 80 is seated in the knob recess and against the mounting wall 40. The breech plate 44 will then lie behind the plane of the mounting plate. The control key 124 is then turned to rotate the key plug 64 counterclockwise from the position shown in FIG. 2. This rotates the sleeve 74 and the breechplate 44 counterclockwise from the position shown and carries the

lugs

51, 55 and 57 of the breech plate behind the inward projecting

lugs

48, 52 and 56 of the mounting wall 40, to lock the core assembly in such mounting wall. The facing ring 89 bears against the mounting wall 40 near its periphery, and lugs of the breech plate 44 bear against the back face of the mounting wall 40. The control key is then removed, and the lock core remains in securely installed position for operation in the usual manner by an operating key.

The particular shape of the breech plate and its interrelation with the other structure provides especially advantageous mounting and operation. The annular section of the breech plate 44 engages at its inner periphery with the sleeve 74, and has outward-projecting

lugs

51, 55 and 57 which define outer peripheral notches. The notch at the top of FIG. 2 is a wide notch 49 through and beyond which the forward extending nose portion 76 of the core body web 62 projects for engagement with the notch 46 in the mounting wall 40. Such wide breech plate notch is defined by the

lugs

57 and 51 which serve as stop lugs and are spaced to permit operative rotation of the breech plate and to engage the web 62 as a stop and thereby determine the locked and unlocked positions of the breech plate shown respectively in full lines and dotted lines inFIG. 2.

In cooperation with such structure, the mounting wall 40 contains the deep notch 46 at the top to pass the web of the core body and to interengage the forward nose portion 76 when the lock core is in mounted position. The deep notch 46 is flanked on its counter-clockwise side by a shallower notch 58 to pass the breech lug 57, and such notch 58 is defined at its remote side by the mounting lug 56 with which the breech plate lug 57 engages when moved to locked position. The deep notch 46 is flanked on its clockwise side by the mounting lug 48 which is engaged by the breech plate lug 51 when the plate is moved to locked position. For each of these breech plate and mounting plate elements there is a diametrically opposite counterpart so that the core assembly can be mounted in the mounting wall 40 in either of two diametrically reversed positions. In each mounted position, the unsymmetrical core body will be locked against removal by engagement points at the mounting lugs 48 and 56 at opposite sides of the core body web 62, and by a second pair of engagement points at diametrically opposite positions from the first. This will give a balanced breech plate engagement, in the sense that there will be engagements at both sides of the vertical center line and likewise at both sides of the horizontal center line. The breech plate engagement also desirably includes engagements between the breech plate lugs 55 and the mounting lugs 52 at opposite sides of the vertical center line and between the other two engagements at each side of such vertical center line, and these enhance the balenced mounting relationship which I have found advantageous for supporting the unsymmetrical core body assembly, and ensure locking at closely spaced points about the entire periphery of the breech plate and its mounting wall.

It is pointed out that the breech-control sleeve 74 is relatively thin, and that this contributes to low cost while providing a high degree of security. As shown in FIG. 1, the front pin stack 106a contains only a single shear separation face 112, which as shown is aligned with the control shear line 116 by reason of high position of the key cut 115 in the front position on the control key 124. The operating key has a deeper cut 117 at this position, as shown in dotted lines in FIG. 1. The distance between the two

cuts

115 and 117 is equal to the thickness of the sleeve and is substantially less than the distance between the highest and lowest combinating positions of the pins in the pin barrel. By way of example, the sleeve thickness may be equal to two increments in a system having a total of seven combinating positions for the pins, or to three increments in a system having ten combinating positions for the pins.

FIG. 6 shows a modification of the structure of FIGS. l3. The front 174 of the core body web 62 extends farther forward than the front 74 of FIG. 1, and past the front face of the mounting wall 40. The rear of the outer peripheral flange 179 of the face plate 180 is notched at 181 to engage over the front 174, and this locks the face plate 180 against rotation.

FIGS. 7 and 8 show a modified breech plate 144 for use instead of the breech plate 44 for mounting a lock core in the mounting wall 40. Such modified plate 144 has an inner periphery by which it may be mounted on the key plug 64 and control sleeve 74 in the same way as the breech plate 44. The modified plate, instead of having notches cut out between its

lugs

51, 55, and 57, has the material in the notches displaced forwardly to form tongues 15-2 and 156 which lie in front of the front face of the mounting plate 40.

When the breech plate 144 is inserted against the mounting plate 40', the

tongues

152 and 156 engage against the front face of the mounting lugs 52 and 56. When the breech plate is then rotated to locked position (shown in FIGS. 7 and 8), the rotative movement carries the breech plate lugs 55 and 57 behind the mounting lugs 52 and 56, as in the modification of FIGS. 1 and 2. Such movement also carries the

tongues

152 and 156 partly out of alignment with the mounting lugs 52 and 56 but not completely out of overlapping relation. Accordingly, the breech plate will have its

lugs

52 and 56 engaged against the back face of the mounting lugs 52 and 56 and will have its

tongues

152 and 156 engaged against the front face of those lugs. This will firmly lock the breech plate 144 to the mounting plate 40 independently of the action of the face plate and independently of the action of the key plug 64 and key stop in retaining the breech plate and face plate together in a clamping relationship.

I claim:

1. A key-removable, pin tumbler lock core, adapted for mounting in a front breech-mounting wall, comprising a core body having a cylindrical portion for rotatably supporting a key plug, and a pin barrel web having pin-barrel openings in a plurality of pin-barrel positions,

a key plug rotatably mounted in the cylindrical portion and having pin-barrel openings in said positions, the cylindrical portion of the body having a front face positioned rearwardly of the front pin-barrel posi tion, and the web extending forwardly beyond such face in spaced relation with the key plug,

a breech-control sleeve surrounding a front portion of the key plu-g, extending across the front pin-barrel position between the plug and the forwardly extending portion of the web, and having a pin-barrel opening therethrough,

said structure defining an operating shear line at all pin barrel positions, between the outer surface of the key plug and the inner surfaces of the core body cylindrical portion and of the sleeve, and defining a control shear line at the front pin-barrel position, between the sleeve and the forward-extending web portion,

pin stacks in said pin barrel openings normally locking said plug and sleeve against rotation relative to the body,

a breech plate at the front of said key plug, rotatively positioned by said sleeve, and rotatable thereby between breech-locked and unlocked positions,

said pin stacks having operating positions to which they are moved by an operating key, wherein shear separation faces in all stacks are aligned with said operating shear line for normal operation of the lock core by such key,

said front pin stack also having a control position to which it is moved by a control key, wherein a separation face therein is aligned with said control shear line and a pin locks the sleeve to the key plug for rotation by such control key to move the breech plate between said breech-locked and unlocked positions.

2. A lock core according to claim 1, wherein said breech plate includes a plurality of radially projecting lugs having forwardly-disposed faces for engagement behind a breech mounting wall, and a face plate carried by said lock core structure, covering said breech plate and having rearwardly-disposed face areas for engagement in front of such breech mounting wall.

3. A lock core according to claim 2, wherein the breech plate and face plate are axially positioned relative to the core structure and held against separation from each other between a rearward-facing shoulder on the key plug and forward-facing surfaces on the core body and sleeve, the key plug being retained against forward displacement by means engaging the core body.

4. A lock core according to claim 3, wherein said lugs define a wide notch and the front of the core-body web extends through and beyond said notch and is interengaged with the face-plate to hold the same against rotation.

5. A lock core according to claim 1, wherein said breech plate comprises a central annular portion having an inner periphery engaged with said sleeve, and circumferentiallyspaced lugs projecting from said annular portion and defining notches therebetween,

one of said notches being a wide notch through and beyond which a forward-extending portion of said core-body web extends for engagement with a mounting plate to rotationally position the core body there- 6. A lock core according to claim 5, in which said wide notch has a width sufficient to permit rotation of the breech plate, and the lugs defining said notch are positioned to engage said web portion as a stop and thereby determine the locked and unlocked positions of said breech plate.

7. A lock core according to claim 6, in which the lugs and notches of said breech plate are formed and arranged in pairs of diametrically opposite counterparts, whereby the breech plate is diametrically symmetrical to present the same configuration when rotated 180.

8. A look core according to claim 6, in which said I breech plate has two diametrically opposite wide notches defined by two pairs of diametrically opposite lugs.

9. A lock core according to claim 7, in which said breech plate has a single additional pair of diametrically opposite lugs circumferentially spaced between the lugs of said first two pairs whereby to define two spaced notches at each side of the breech plate circumferentially spaced between said wide notches.

10. The combination of a mounting and lock core according to claim 1, said mounting comprising a mounting wall having a breech opening to pass the core body and breech plate when the breech plate is in unlocked position,

said wall having lugs behind which the breech plate engages when turned from unlocked to locked position. 11. The combination of a mounting and a lock core according to claim 2, said mounting comprising a mounting wall having a face portion and defining a forwardly open recess within said face portion,

said recess having a bottom wall containing a breech opening to pass the core body and breech plate when the breech plate is in unlocked position,

said recess being shaped to receive said face plate,

with the face plate interengaging the walls of the recess to position the lock core axially therein,

said bottom recess wall having lugs engageable by the breech plate to secure the lock core in said mounting.

12. The combination of a mounting and a lock core according to claim 8, said mounting comprising a mounting wall having a breech opening,

said breech opening comprising a pair of diametricallyopposite radial notches to pass the web portion of the core body in either of two positions apart,

each of said radial notches being flanked at one side by a notch to pass one of a pair of wide-notch-defining lugs of the breech plate and at the other side by a lug for engagement by the other lug of such breech-plate pair.

13. A lock core according to claim 1, wherein said breec'h control sleeve is of less radial thickness between the key plug and the forwardly extending portion of the web, and said shear lines are spaced a less distance than the distance between the highest and lowest combinating positions of the front tumbler pin stack, and the front pin stack contains a single separation face which provides shear separation respectively at both of said shear lines when positioned by operating and control keys.

14. A lock structure having a key-removable, frontbreech mounted pin tumbler lock core, comprising a core body having a cylindrical portion for rotatably supporting a key plug, and a pin barrel web having pin-barrel openings in a plurality of pin-barrel positions,

at key plug rotatably mounted in the cylindrical portion and having pin-barrel openings in said positions,

a breech control sleeve surrounding the key plug and extending across at least one pin-barrel position and having a pin-barrel opening at each such position,

said structure defining operating and control shear lines at the inner and outer faces of such sleeve,

pin stacks in said pin barrel openings normally lying across said shear lines and movable by operating and control keys into positions for shear separation at said shear lines,

a breech plate at the front of said key plug rotatively position by said sleeve and rotatable thereby between breech locked and unlocked positions,

said breech plate havinga central annular section engaged at its inner periphery with said sleeve and having circumferentially-spaced outward-projecting lugs shorter than said core body web and defining notches at its outer periphery,

a mounting wall ,for said core, having an annular peripheral portion and inward-projecting lugs defining a breech opening for the reception of said breech plate and lock core,

said breech plate having a 'wide notch through and beyond which a forward portion of said web extends for engagement with a notch in the mounting plate, said wide breech-plate notch being defined by a pair of stop lugs spaced to permit operative rotation of the breech plate and to engage said web as a stop and thereby determine the locked and unlocked positions of the breech plate,

the mounting wall having a deep notch to pass the web of the core body and to interengage the forwad portion of the web, said deep notch being flanked on one side by a shallower notch which is formed to pass one of said pair of stop lugs and is defined at its remote side by a mounting lug for mounting engagement by said stop lug, said deep notch being flanked on the other side by a mounting lug positioned for engagement by the other of said pair of breech-plate stop lugs,

each of said breech plate and mounting wall elements having a counterpart at a diametrically opposite position,

the breech plate and mounting plate thereby having a pair of engagement points at opposite sides of the core body web and a second pair at diametrically opposite positions therefrom whereby the asymmetric core body may be mounted in either of two positions 180 apart and will be retained in each position by a balanced breech lock mounting.

15. A lock structure according to claim 14, with the addition of an intermediate breech-plate lug between the said stop lugs at each side of said center line through said diametrically opposite wide notches, and of a mounting leg on the mounting wall for engagement by each of said intermediate lugs.

16. A key-removable, pin tumbler lock core adapted for mounting in a front breech-mounting wall, comprising a core body having a cylindrical portion for rotatably supporting a key plug, and a pin barrel web having pin-barrel openings in a plurality of pin-barrel positions,

a key plug rotatably mounted in the cylindrical portion and having pin-barrel openings in said positions,

a breech plate at the front of said key plug rotatively positioned by said sleeve and rotatable thereby between breech locked and unlocked positions,

said breech plate having a central annular section engaged at its inner periphery with said sleeve and having circumferentially-spaced outward-projecting lugs shorter than said core body web and defining notches at its outer periphery,

said breech plate having a wide notch through and beyond which a forward portion of said web extends for engagement with the mounting wall, said wide notch being defined by a pair of stop lugs spaced to permit operative rotation of the breech plate and to engage said web as a stop and thereby determine the locked and unlocked positions of the breech plate,

one of said pair of stop lugs forming an engagement lug having an unlocked position spaced from said web to pass a mounting lug therebetween, the other of said pair of stop lugs having a remote edge form ing an engagement lug for engagement with a mounting lug on the opposite side of the web,

each of said breech plate engagement lugs having a diametrically-opposite counterpart whereby the breech plate provides for mounting the asymmetric core body in either of two diametrically reversed positions, and for retaining the same in a mounting by balanced pairs of engagement points at opposite sides of the web positions.

17. A mounting for a key-removable, pin-tumbler lock core according to claim 16, comprising a mounting wall having an annular peripheral portion and inward projecting lugs defining a breech opening for the reception of the lock core body and breech plate,

said mounting wall having a deep notch to pass the web of the core body and to interengage the forward portion of the core-body web,

said deep notch being flanked on one side by a shallower notch which is formed to pass one of the pair of stop lugs and is defined at its remote side by a mounting lug for mounting engagement by such one stop lug when the breech plate is rotated to locked position, said deep notch being flanked on the other side by a mounting lug adapted to pass between the core body web and the other stop lug during insertion of the core assembly in the mounting, and to be engaged by such other stop lug when the breech plate is so rotated,

each of said mounting wall lugs and notches having a diametrically opposite counterpart whereby the asymmetric core body can be mounted in such wall in either of two diametrically-reversed positions and the mounting wall provides breech engagement points in balanced pairs at opposite sides of the core body web positions.

18. A mounting according to claim 17, wherein the mounting plate, in addition to the first-named mounting lug at the remote side of each shallow notch and the second-named mounting lug flanking the other side of the deep notch, and their counterpart mounting lugs, carries a third mounting lug between each such named lug and the counterpart of the other such named lug.

19. A lock core according to claim 1, wherein said breech plate includes a plurality of radially projecting breech lugs having forwardly-disposed faces for engagement behind spaced mounting lugs of a breech mounting wall, and said breech plate also includes a plurality of projecting tongues displaced forwardly from said breech plate for engagement against the front of said mounting lugs.

20. A combination according to claim 10, wherein said breech plate includes a plurality of radially projecting breech lugs having forwardly-disposed faces for engagement behind spaced mounting lugs of a breech mounting wall, and said breech plate also includes a plurality of projecting tongues displaced forwardly from said breech plate for engagement against the front of said mounting lugs.

21. A lock core according to claim 16, wherein said breech plate includes a plurality of radially projecting breech lugs having forwardly-disposed faces for engagement behind spaced mounting lugs of a breech mounting wall, and said breech plate also includes a plurality of projecting tongues displaced forwardly from said breech plate for engagement against the front of said mounting lugs.

References Cited UNITED STATES PATENTS 2,807,158 9/1957 Best -370 2,907,197 10/1959 Best 70369 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner US. Cl. X.R.