Abstract:
Pop-Up Indicator, Replacement Lock-Cylinder with distinctive keys for owner, employee (or acquaintance), and some third party whose right to enter is legitimate only upon notice or in an emergency. The pop-up indicators are brightly and differently colored. The lock cannot be circumvented by pressing a pop-up in and endeavoring to turn the key, because the pop-up&#39;s barrel blocks rotation of the lock&#39;s core unless the pop-up is fully extended. Once triggered, the pop-up remains visible and in locked position until the lock owner resets it. A tactile indicator of sought entry is transmitted to the owner upon key insertion and rotation, as well. Meanwhile, the employee and/or third party enjoys unimpeded access. The owner will thus know whether the employee has been over—to inspect for termites, walk the dog, etc.—and the third party cannot allege lockout lease breaking. The lock operates quite normally with either or both pop-ups triggered. Since only the employee&#39;s key or the third-party key (but not the owner&#39;s key) is capable of triggering a pop-up, if these keys have been given out, the owner obtains prima facie proof of sought entry. The owner may wish to leave a pop-up exposed in order to show a witness or possibly the police.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     PREFERENCE TO A MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     Indicator locks, particularly having non-numeric indicators, broadly define the art wherein the present invention resides. Lock engagement—has the latch and/or dead bolt been thrown?—or else room occupancy—did somebody now inside this room lock this lock?—are commonly indicated conditions. Left unaddressed by the prior art of which applicant is aware is a different, and essentially evidentiary, question. Given the desirability of permitting a known party to enter a lock-protected space ad hoc or on schedule (a landlord in an emergency, a house sitter to feed cats, etc.), how should a lock best indicate that such an event has occurred, while preserving its operability for all of the parties having keys, meanwhile providing the lock owner with the option of presenting evidence of, and/or of confronting with evidence of, entry improperly sought or gained, or of a trust neglected? 
     Cylindrical elements that are geared or journaled to rise up or are pushed by a spring-loaded lever into full extension are well-known as indicator devices. Parts for lock mechanisms, including such button-form indicators, generally are made from cast metal and/or from sintered, powdered metal, and springs of all sorts find lock-mechanism application. For short, cylindrical parts a half-inch in diameter, tolerances of ±0.3% or better are economically and routinely achieved using powdered-metal injection molding. Tight tolerances make possible functional refinement. 
     The principal objective of the present invention is to answer, then, by means of an exemplary, high-precision lock producible with advanced but available technology, the evidentiary question articulated above. 
     SURVEY OF BACKGROUND ART 
     U.S. Pat. No. 1,177,151 to Teich (1916) discloses a lock indicating mechanism having a button-type indicator driven by a spring always into the lock (p. 3, lines 82-84), not outwardly as in the present invention. Teich&#39;s indicator furthermore requires the movement of a bolt, this movement having the effect of deadlocking the door to which the lock is applied, for the shank of Teich&#39;s indicator to become visible. In the present invention, merely the slight rotation of a key in the lock, occurring well before any bolt is thrown, is all that is required for that key&#39;s associated indicator to pop out. Teich&#39;s motivation, described on p. 3, lines 101-116, is to prevent an occupied room from being disturbed. The present invention&#39;s motivation is broader and has to do with trust not being misplaced or abused. 
     U.S. Pat. Nos. 1,154,142 and 1,177,152 to Teich (1915, 1916) disclose three classes of keys. These keys, however, are hierarchical, in that the operation of Teich&#39;s lock by at least one of the keys excludes operation of the lock by the remaining key or keys (U.S. Pat. No. 1,154,142 p. 1, lines 18-21; and 1,177,152 p. 1, lines 16-19). In the present invention all of the keys are equal with respect to operation of the lock qua lock. No key excludes any other key. 
     U.S. Pat. No. 2,638,770 to Gutman (1953) discloses a lock-indicating mechanism having a button-type indicator driven by a spring into the lock (FIG.  7  &amp; col. 3, lines 71 to col. 4, in 1), not outwardly as in the present invention. Gutman&#39;s indicator is furthermore designed to indicate whether a dead bolt has been thrown from inside or from outside a room, and is operable exclusively by the retractors that operate the lock&#39;s dead bolt. Both the mechanism as well as motivation of Gutman&#39;s indicator are entirely different from the present invention&#39;s. 
     U.S. Pat. No. 3,336,775 to Russell et al. (1967) shows a button-type indicator driven by a spring into the lock (FIG.  5  &amp; col. 3, lines 34-38). Furthermore, “the position of the indicator member is directly related to the position of [the lock&#39;s] dead bolt” [col. 4, lines 37-38]. The mechanism and motivation of this indicator lock are entirely different from the present invention&#39;s. 
     U.S. Pat. No. 526,740 to Rapaport (1894) appears at first glance to have an indicator means, “dog  28 ”, that is urged out of Rapaport&#39;s combination lock. On reading, however, we discover that “dog  28 ” is not an indicator means at all but is rather a counting means (page 2, lines 77-80). In fact, “dog  28 ” indicates nothing whatever about the present condition of Rapaport&#39;s lock nor about its use by parties with knowledge of its combination. 
     U.S. Pat 2,793,522 to Tornoe (1957) discloses a geared indicator able to show only whether the lock is locked or not. The mechanism and motivation of Tornoe&#39;s lock differ entirely from the present invention&#39;s. Interesting in Tornoe is FIG. 2, because this figure is what a linguist might term a near homograph of the present invention. What the unnumbered circle to the right of tumbler  18  in Tornoe&#39;s FIG. 2 might be, Tornoe never says, even though this detail appears again in mirror image in FIGS. 3 and 4, and appears slightly extended in FIG. 5 (n.b.  37  refers to the lock face). Homographs like homonyms, however, have totally different meanings. 
     U.S. Pat. No. 3,885,409 to Genakis (1975) shows a cylinder lock having “a set of independently rotational rings on the plug, one ring for each pinway” [col 2, lines 48-50]. Genakis then adds further rings, but is motivated exclusively by two desires: to increase the number of lock combinations and to make the lock more difficult to pick. Genakis gives no shape to his rings that might enable them to serve in additional, functional capacities. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention confines cylindrical indicators, the “pop-ups”, in cylindrical bores parallel to and close to the lock&#39;s rotatable core. The pop-ups are urged forward from behind by springs but are prevented from movement by pins which drop into bores orthogonal to the pop-up&#39;s length. The pop-ups are now armed. Ring-like elements are mounted over the lock-core that are so formed as to be able, on rotation with the core by a key, to lift these obstructing pins and thus to release the po-pup to pop up. Stops prevent the pop-ups from shooting out of the lock. In the instant before a stop is encountered, a pin falls from above into a bore in the pop-up placed orthogonal to its direction of motion, thus locking the pop-up, so that it cannot be pressed back in. A different key, which cannot trigger a po-pup, has the ability, via a different, core-mounted ring, to lift this locking pin, so that the pop-up may be reset. In the preferred embodiment, two independent pop-ups are provided. The pop-ups&#39; armed positions may be symbolically indicated in a variety of ways, as for example by the letters A and B (alternatively by such non-lingual symbols as □ and ◯), with the pop-ups&#39; respective “popped-out”, or indicator, positions being indicated symbolically by AA and BB (alternatively by ▪ and ) Having two pop-ups entails locating the lock&#39;s tumblers asymmetrically in the plane containing their axes. This is unusual and enhances considerably the security of the lock against anyone not thoroughly familiar with its construction and not equipped with the necessary, proprietary lock picks. 
     The present invention has several important objects, among which are: 
     1) security against unannounced entry by persons having contractually-guaranteed access to a key 
     2) security against an intruder who has somehow gained access to a key 
     3) security against curiosity snooping 
     4) enhanced ability to monitor the performance of an employee 
     5) enhanced security through keys having asymmetrically placed keycuts 
     6) enhanced security through keys having independent, dummy keycuts 
    
    
     These and still-further objects and advantages of the present invention will become apparent from a consideration of the following detailed specification, drawings, and appended claims. 
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     Referring to the drawings, wherein like reference characters indicate like parts or elements throughout the several views, and wherein arrowheads indicate physically-composite objects whose resolution into numbered, constituent parts occurs when germane to the discussion: 
     FIG. 1 is a front, isometric drawing of the present invention&#39;s preferred embodiment. 
     FIG. 2 is a rear, isometric drawing of the embodiment in FIG.  1 . 
     FIG. 3 is a front isometric view of the right indicator-element introduced in FIG.  1 . 
     FIG. 4 is the indicator-element shown in FIG. 3 rotated 25° about it&#39;s long axis. 
     FIG. 5 is the indicator-element shown in FIG. 3 rotated 90° about it&#39;s long axis. 
     FIG. 6 is a front isometric view of the left indicator-element introduced in FIG.  1 . 
     FIG. 7 is the indicator-element shown in FIG. 6 rotated 25° about it&#39;s long axis. 
     FIG. 8 is the indicator-element shown in FIG. 6 rotated 90° about it&#39;s long axis. 
     FIG. 9 is a front isometric view of the core of the embodiment introduced in FIG.  1 . 
     FIG. 10 is a rear isometric view of the core of the embodiment shown in FIG. 9 with a portion of the tail-piece 
     FIG. 11 is a front isometric view of the core shown in FIG. 9 with five, ring-like elements mounted thereupon. 
     FIG. 12 is a top isometric view of the middle, ring-like element introduced in FIG.  11 . 
     FIG. 13 is a top isometric view of the front, ring-like element introduced in FIG.  11 . 
     FIG. 14 is a front plan view of the embodiment of FIG. 1 with the key thereto removed 
     FIG. 15 is a top, plan, partial cutaway view of the embodiment of FIG. 1 taken along line  15 — 15  of FIG.  14  and with the shaded portions of FIG. 14 removed and with two like elements partially broken away. 
     FIG. 16 is a front plan view of the embodiment of FIG. 1 but with a different key thereto inserted 
     FIG. 17 is a cross-sectional view of the embodiment of FIG. 1, taken along line  17 — 17  of FIG. 16, and with the key of FIG. 16 inserted into the lock but with the key not cross-sectioned. 
     FIG. 18 is a cross-sectional view of the embodiment of FIG. 1, taken along line  18 - 18  of FIG. 16, but showing a different key than the keys in FIGS. 1 and 17 inserted into the lock and with the key not cross-sectioned. 
     FIG. 19 is a cross-sectional view of the embodiment of FIG. 1, taken along line  19 — 19  of FIG. 16, and showing the key in FIG. 1 inserted into the lock and with the key not crosssectioned. 
     FIG. 20 is a front plan view of the embodiment of FIG. 1 with the key and tumblers thereof removed. 
     FIG. 21 is a cross-sectional view of the elements in FIG. 20 taken along line  21 — 21  of FIG.  20 . 
     FIG. 22 is a front plan view of the embodiment of FIG. 1 with the key and tumblers thereof removed. 
     FIG. 23 is a cross-sectional view of the elements of FIG. 22 taken along line  23 — 23  of FIG.  22 . 
     FIG. 24 is an enlarged and partly fragmentary view of several of the elements seen in dotted box  24  of FIG.  23 . 
     FIG. 25 is an enlarged and partly fragmentary view of several of the elements seen in dotted box  25  of FIG. 23, but as these elements are interrelated in FIG.  15 . 
     FIG. 26 is a rear plan view of the largest single element of the embodiment of FIG.  1 . 
     FIG. 27 is a cross-sectional view of the element of FIG. 26 taken along broken, rectilinear line  27 — 27  of FIG.  26 . 
     FIG. 28 is a cross-sectional view of the element of FIG. 26 taken along broken, rectilinear line  28 — 28  of FIG.  26 . 
     FIG. 29 is a cross-sectional view of the element of FIG. 26 taken along line  29 — 29  of FIG.  26 . 
     FIG. 30 is a front isometric view of the plate seen attached to the rear, or distal, end of the preferred embodiment in FIG.  2 . 
     FIG. 31 is a cross-sectional view of the plate of FIG. 30 taken along line  31 — 31  of FIG.  30 . 
     FIG. 32 is a cross-sectional view of the plate of FIG. 30 taken along broken., rectilinear line  32 — 32  of FIG.  30 . 
     FIG. 33 is a cross-sectional view of the plate of FIG. 30 taken along line  33 — 33  of FIG.  30 . 
     FIG. 34 is a front, plan view of the embodiment of FIG. 1 but with the key of FIG. 18 inserted into the core. 
     FIG. 35 is a cross-sectional view taken along line  35 — 35  of FIG. 15, but taken prior to the removal of the portions shaded in FIG.  14  and showing the moving parts of the embodiment of FIG.  1 . intersected by line  35 — 35  and before being moved. 
     FIG. 36 shows the key and core of FIG. 34 slightly counterclock-wise rotated with respect to the remaining elements of the lock. 
     FIG. 37 shows the moving parts of FIG. 35 rotated as in FIG.  36 . 
     FIG. 38 shows the key and core of FIG. 36 slightly counterclock-wise rotated with respect to the remaining elements of the lock. 
     FIG. 39 shows the moving parts of FIG. 37 rotated as in FIG.  38 . 
     FIG. 40 shows the key and core of FIG. 38 counterclockwise rotated with respect to the remaining elements of the lock and nearly back to their position in FIG.  34 . 
     FIG. 41 shows the moving parts of FIG. 39 rotated as in FIG.  40 . 
     FIG. 42 is a front, plan view of the embodiment of FIG. 1 but with the key of FIG. 17 inserted into the core. 
     FIG. 43 is a cross-sectional view taken along line  43 — 43  of FIG. 15, but taken prior to the removal of the portions shaded in FIG.  14  and showing the moving parts of the embodiment of FIG.  1 . intersected by line  43 — 43  and before being moved. 
     FIG. 44 shows the key and core of FIG. 42 slightly counterclockwise rotated with respect to the remaining elements of the lock, such that the key lines up with the left indicator element introduced in FIG.  1 . 
     FIG. 45 shows the moving parts of FIG. 43 rotated as in FIG.  44 . 
     FIG. 46 is a table. 
     FIG. 47 is a front plan view of an alternate embodiment of the present invention having just one indicator element. 
     FIG. 48 is a top, plan, partial cutaway view of the alternate embodiment introduced in FIG. 47 taken along line  48 — 48  of FIG.  47  and with the portions shaded in FIG. 47 removed and with an element partially broken away. 
     FIG. 49 is a rear plan view of the alternate embodiment shown in FIGS. 47 and 48 but the rear plate thereto removed and emptied of moving parts. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 and 2 show lock  1  having body  10 , flange  120 , rear plate  50 , tail-piece  90 , and M-key  800 . Body  10  comprises barrel element  110 , flat facets  113   r  and  113   l  abutting tumbler head  130 , and flat facets  114   r  and  114   l  carrying, respectively, pop-up heads  140  and  150 . Flange  120  has proximal face  121 , rim  122 , and distal face  123 . Body  10  and flange  120  are integrally formed from metal, as by molding. (Throughout the specification and claims, r=right and l=left, p=proximal and d=distal, always with respect to a lock-user looking square at face  121 ) 
     Tumbler head  130  carries hold-down strip  131  held in place by six tabs  132 , which are forcibly crimped to overlap and press down upon strip  131 , in the usual manner. Pop-up head  140  carries hold-down strip  141  retained by six, crimped tabs  142 , and pop-up head  150  carries hold-down strip  151  retained by six, crimped tabs  152 . 
     Able to turn within body  10  is core  20 , into which M-key  800  is shown inserted. Above and to the left and right of core  20  are indicator means  750  and  850 , called pop-ups after their method of functioning. Pop-up  750  is armed and thus extends only very slightly beyond face  121 , about 0.5% of its overall length, whereas pop-up  850  has been triggered by a slight rotation of M-key  800  (preview FIGS. 34-41) and, thus, is fully extended, about 16% of its overall length. The difference in extension is quite noticeable. Band  853  emphasizes the condition of pop-up  850  and here is shown to be red. M-key  800  has identifying aperture  806 , here the letter M for Management, and key-chain aperture  807 . 
     Seen best in FIG. 2 is rear plate  50  attached to body  10 , i.e. to the distal end of lock  1 , by hex-head allen cap-screws  555  and  556 . Plate  50  has bore  590  through which tail-piece  90  extends. Body  10  has threaded holes  101  and  102  by means of which lock  1  may be coupled to an otherwise garden-variety lock mechanism using the standard break-off screws. 
     FIG. 3 shows pop-up  850 , associated with M-key  800 . Pop-up  850 , substantially a long cylinder with a corresponding length-wise axis, has body  855  in which features are defined by the elimination or absence of material. Proximal face  851  has rim  852 , behind which is colored barrel  853 , here red. Barrel  853  is slightly less in diameter than body  855 , so that a plastic band or a thin paint layer, whatever colors it, will not be abraded when the pop-up moves. The colored portion of pop-up  850 , whether barrel-shaped as here or shaped otherwise, needs merely to be recessed from the surface of pop-up  850 . Trough  820  extends lengthwise and parallel to pop-up  850 &#39;s lengthwise axis, and has flat bottom  822 , left side wall  823 , right side wall  824 , proximal cylindrical wall  825 , and distal cylindrical wall  827 . At the proximal end of trough  820  is bore  821 , which extends through body  855  perpendicular to flat bottom  822 . At the distal end of trough  820  is bore  829 , which extends through body  855  perpendicular to face  822 . Pop-up  850  has flat rear face  856 . 
     FIG. 4 shows pop-up  850  rotated  250  about its long axis. Coming into view are features seen best in FIG.  5 . 
     FIG. 5 shows pop-up  850  rotated 90° about its long axis, showing disjoint, coplanar under surfaces  857  and  858 , both parallel to trough bottom  822 . Surface  857  stops short of barrel  853 , resulting in front cylindrical remainder  859 . Surface  858  extends to the distal end of body  855 , where it intersects rear face  856  perpendicularly. Bore  829  ends at surface  858 . Between surfaces  857  and  858  is fully-cylindrical blocking portion  854  through which bore  821  extends. Blocking portion  854  has proximal, flat wall  828 , perpendicular to surface  857 . 
     FIG. 6 shows pop-up  750 , associated with B-key  700  (preview FIGS.  35 - 41 ). Pop-up  750 , substantially a long cylinder with a corresponding lengthwise axis, has body  755  in which features are defined by the elimination or absence of material. Proximal face  751  has rim  752 , behind which is barrel  753 , here colored green. Barrel  753  is slightly less in diameter than body  755 , so that a plastic band or a thin paint layer, whatever colors it, will not be abraded when the pop-up moves. The colored portion of pop-up  750 , whether barrel-shaped as here or shaped otherwise, merely needs to be recessed from the surface of pop-up  750 . Trough  720  extends lengthwise and parallel to pop-up  750 &#39;s lengthwise axis and has flat bottom  722 , left side wall  723 , right side wall  724 , proximal cylindrical wall  725 , and distal cylindrical wall  727 . Between wall  725  and barrel  753  is cylindrical remainder portion  759 . At the proximal end of trough  720  is bore  721 , which extends through body  755  perpendicular to flat bottom  722 . At the distal end of trough  720  is bore  729 , which extends through body  755  perpendicular to flat bottom  722 . Pop-up  750  has flat rear face  756 . 
     FIG. 7 shows pop-up  750  rotated 25° about its long axis. Coming into view are features seen best in FIG.  8 . 
     FIG. 8 shows pop-up  750  rotated 90° about its long axis, and showing flat under surface  758 , parallel to trough bottom  722 . Surface  758  stops short of barrel  753 , so that fully-cylindrical blocking portion  754  is left, through which bore  721  extends. Surface  758  extends to the distal end of body  755 , where it intersects rear face  756  perpendicularly. Bore  729  ends at surface  758 . The lengthwise axis of pop-up  750  may be indicated symbolically in a variety of ways, as for example by X 1 . The lengthwise axis of pop-up  850  could then by analogy be indicated by X 2 . 
     FIG. 9 shows lock core  20  removed from lock  1 . Core  20  has cylindrical, core body  220 , and coaxial, cylindrical stop ring  221 . Stop ring  221  has a larger diameter than core body  220  and is integrally formed with core  20 . Stop ring  221  is partly cut away by slot  250  by means of which core  20  admits and communicates with tail-piece  90 . At the distal end of stop ring  221  and separated by slot  250  are cylindrical rear portion  2228  and  222   i  (preview FIG.  10 ), integrally formed with core  20 , which continue core body  220  a short distance beyond stop ring  221 , thus giving core  20  a single, lengthwise axis. Core  20  has proximal face  212 , keyway  213 , key-start cone  214 , and end bevel  215 . Core  20  further has five lock-tumbler bores, namely bores  270 ,  280 ,  260 ,  230   p  and  230   d . Bore  270  is associated with employee&#39;s B-key  700 , trigger means  730 , and pop-up  750  (preview FIGS.  11  and  18 ). Bore  280  is associated with management&#39;s M-key  800 , trigger means  830 , and pop-up  850  (preview FIGS.  11  and  19 ). Bore  260  is associated with lock-owner&#39;s A-key  600  and with reset ring  630  (preview FIGS.  11  and  17 ). Bores  230   p  and  230   d  are associated with plain rings  300   p  and  300   d , respectively. 
     Bores  270 ,  280 ,  260 ,  230   p  and  230   d  are arrayed asymmetrically along the length of core body  220 . This will turn out to be both an unusual and useful asymmetry. 
     FIG. 10 shows core  20  from behind with tail-piece  90  inserted into slot  250 . Tail-piece  90  has the usual notches  91  and break-off segments  92 , by means of which its length may be adjusted to suit a particular application. Tail-piece  90  permits lock  1  to communicate with a larger locking mechanism, lock  1  ultimately becoming a component part thereof, thus permitting lock  1  to throw, for example, a dead bolt, generally by turning tail-piece  90  at least a quarter of a turn. The proximal end of tail-piece  90  is T-shaped, with symmetrical, extended wings  93  having symmetrical distal faces  99 . This T-shaped end of tail piece  90  has v-shaped notch  97 , a standard feature that allows keys to enter core  20  completely. 
     FIG. 11 shows core  20  with trigger means  730 , trigger means  830 , reset means  630 , and plain rings  300   p  and  300   d  mounted upon it. These ring-like or sleeve-like elements of lock  1  are substantially tubular in shape, albeit quite short in relation to their length, and have cylindrical inner surfaces all of the same diameter that bear lightly upon cylindrical core body  220 . Their outermost surfaces are small, cylindrical segments the same in radius as the outer, cylindrical surface of stop ring  221 . The shape of asymmetric trigger means  830  is congruent in detail to the shape of trigger means  730 , however means  830  faces oppositely on core  20 , that is, the like faces of means  730  and  830  lie adjacent to one another. The shapes of asymmetric trigger means  830  and  730  may be indicated symbolically in a variety of ways, as for example by T 1  and T 2 , respectively. The shapes&#39; congruency might then be expressed as T 1 ≡T 2 , using conventional, geometric notation. Plain rings  300   p  and  300   d  have outer surfaces  332   p  and  332   d  and tumbler bores  333   p  and  333   d , respectively. 
     FIG. 12 shows pop-up reset means  630 , which only the owner&#39;s A-key  600  can turn. Reset means  630  has inside surface  639 , distal edge  636 , proximal annular edge  638 , and outside surface  632 . Extending radially outward from surface  632  and integrally formed with it and, thus, with means  630  are left reset plateau  6311 , right reset plateau  631   r  and tumbler plateau  631   t . In the embodiment of the invention herein illustrated, these plateaus have the same width, which is somewhat greater than half the width of reset means  630 . Left, tumbler, and right reset plateaus  6311 ,  631   t , and  631   r  each have a left and right beveled face, numbered  63511  and  6351   r ,  635   tl  and  635   tr , and  635   rl  and  635   rr , respectively. Each plateau furthermore has a top face, numbered  6341 ,  634   t , and  634   r , respectively. Tumbler plateau  631   t  has tumbler bore  633 , which extends perpendicularly through surface  634   t  and entirely through means  630 . Bore  633  lies tangent to distal edge  636 , which, apart from those portions of edge  636  contiguous with plateaus  631   l ,  631   t , and  631   r , is substantially annular in shape. To prevent sharp edges at the point of tangency, bore  633  is cut back slightly, resulting in chamfers  637 . 
     FIG. 13 shows trigger means  730 , which only the employee&#39;s B-key  700  can turn. Trigger means  730  has inside surface  739 , proximal edge  738 , distal annular edge  736 , and outside surface  732 . Extending from radially outward from surface  732  and integrally formed with means  730  is blocking plateau  731 , having left and right beveled faces  7351  and  735   r , and top face  734 . In the embodiment of the invention herein illustrated, plateau  731  is one half the width of means  730 . Means  730  further has tumbler bore  733 , which extends perpendicularly through surface  732  and entirely through means  730 . Bore  733  lies tangent to proximal edge  738 , which, apart from those portions of edge  738  contiguous with plateau  731 , is substantially annular in shape. To prevent sharp edges at the point of tangency, bore  733  is cut back slightly, resulting in chamfers  737 . 
     Means  730  furthermore has trigger  740 , which is a substantially wedge-shaped cutout entirely through means  730  and which extends from proximal edge  738  to trigger face  746 , trigger face  746  lying very slightly, a few thousandths of an inch in practice, beyond the mid-circumference of cylindrical outer surface  732 , i.e. a bit closer to edge  736  than to edge  738 , in order to accommodate upper pin  25  without binding (preview FIGS.  17  and  38 - 41 ). Pin  25  will enter trigger  740  in cases where core  20  undertakes a complete revolution. Trigger  740  has left beveled face  741  and right beveled face  742 . The intersections of bevels  741  and  742  with face  746  are filleted three-dimensionally,  117  resulting in top rounded corners  744  and  745 , respectively, and in bottom rounded end  743 . These roundings prevent stress from concentrating. Beveled faces  741  and  742  do not meet, but are spaced apart, so that trigger  740  has a U-shaped bottom aperture lying just adjacent to core body  220 . 
     Trigger means  830 , which only management&#39;s B-key  800  can turn is identical to means  700 . References in the specification having an 8 in the hundred&#39;s place may be identified by substituting a 7 and then identifying the numbered structure in FIG.  13 . 
     In the embodiment of the invention herein illustrated, ring-like elements  730 ,  830 ,  630 ,  300   p  and  300   d  all have the same width. This width is illustrated to be twice the diameter of tumbler bores  733 ,  833 ,  633 ,  333   p , and  333   d , which here all have the same diameter. The ring-like elements, however, need not all have the same width, and the bores need not all have the same diameter, nor do the bores or tumblers need necessarily to be substantially cylindrical. The placement of each bore along core  20  may be described by means of a reference point, these reference points all lying in a single plane perpendicular to face  212 , and each point being the geometrical center of gravity of the figure described by that point&#39;s respective bore when that bore is cut by the aforesaid single plane, the plane preferably intersecting the bores perpendicularly as well. For the cylindrical bores shown here in core  20 , these reference points reduce simply to the midpoints of the circles described in a plane chosen to cut the bores perpendicular to the shared plane of the bores&#39; axes. 
     FIG. 14 shows dashed cut-lines applied to lock l in order to define FIG.  15 . Note that the straight cut-lines pass through diameters of pop-ups  750  and  850 , so that one half of each pop-up will be removed. The circular-arc cut-line between the straight cut-lines has a radius slightly greater than that of the outermost surfaces of the ring-like elements of lock  1  and in fact equal to the radius of bore  103  (preview FIG.  26 ). Proximal tumbler  27  shows through keyway  213  because no key is in the lock. All lock pins and tumblers have been removed in FIG. 15, since the drawing would be cluttered pointlessly by their crosssections. 
     FIG. 15 shows all the elements of lock  1  thus fair described. Additionally, springs  470  and  480  are seen to be respectively compressed and extended against distal faces  756  and  856  (see FIGS. 6 &amp; 3) of pop-ups  750  and  850 . When compressed against their respective pop-ups  750  and  850 , springs  470  and  570  urge pop-ups  750  and  850  out of lock  1 , unlike the springs in the prior art discussed above. Springs  470  and  480  may be fairly stiff and need not be able to extend much farther than shown here by extended spring  480 . This is because springs  470  and  480  accomplish their work by impulse upon release from a compressed state. Pop-up  750  is shown to be armed and nearly flush with face  121  of flange  120 , while pop-up  850  is shown fully extended beyond face  121 , having been triggered. Pop-up  850 , indicates, by means of colored band  853 , that entry into the space protected by lock  1  has been sought and/or obtained. Springs  470  and  480  nestle snugly in bind-hole pockets  570  and  580  of rear plate  50 , thus maintaining these springs&#39; alignment with the axes of their respective pop-ups. Cylindrical pop-up bores  170  and  180  extend the length of lock body  10  and flange  120 . 
     Distal, lower pop-up pins  760   i  and  860   i  reside in pop-up bores  729  and  829  (see FIGS.  6  and  3 ), respectively. Proximal, lower pop-up pins  770   i  and  870   i  reside in bores  721  and  821  (see FIGS.  6  and  3 ), respectively. 
     Resting perpendicularly on trough bottom  722  (see FIG. 6) are distal and proximal tubular pin sleeves  710   d  and  710   p . Residing within sleeves  710   d  and  710   p  are, respectively, distal, upper pop-up pin  760   s  and proximal upper pop-up pin  770   s  (s=supra and i=infra throughout the specification). Distal and proximal pin springs  711   d  and  711   p  press down, respectively, upon pins  760   s  is and  770   s . Springs  711   d  and  711   p  are held compressed by hold down  151 , here shown partly broken away. Hold down  151  does not in fact touch sleeves  710   d  and  710   p  (preview FIGS.  24  and  25 ), only springs  711   d  and  711   p.    
     All pop-up pins and sleeves of lock  1  are toleranced to slide freely within their containments (the pins within the sleeves, the sleeves within lock body  10 ). The fact that pop-up  750  is under spring pressure from behind when armed coupled with these tolerances gives rise to the slight extension (about 0.004″ in actual practice) of pop-up  750  beyond face  121 , as shown here and in FIG. 1, being depicted with a slight, optional bevel. (Pop-up  850  is depicted without a bevel). The spring pressure takes up, so to speak, the “slack” of the tolerances. 
     Distal bottom pin  760   i  rests on the outer surface  332   p  of plain ring  300   p  (see FIG.  11 ). Proximal bottom pin  770   i  rests on the body  220  (see FIG. 9) of core  20  seen here through the U-shaped aperture of trigger  740  of trigger means  730   i  (see FIG.  13 ). Pop-up  750  is prevented from shooting forward by pin  770   s , which extends a distance into bore  721  of pop-up  750  (see FIG.  6 ). 
     Resting perpendicularly on trough bottom  822  (see FIG. 3) of pop-up  850  are distal and proximal tubular pin sleeves  810   d  and  810   p , identical to each other and to the sleeves for pop-up  750 . Residing within sleeves  810   d  and  810   p  are, respectively, distal upper pop-up pin  860   s  and proximal upper pop-up pin  870   s . Distal and proximal pin springs  811   d  and  811   p , identical to each other and to the springs for pop-up  750 , press down, respectively, upon pins  860   s  and  870   s . Springs  811   d  and  811   p  are held compressed by hold down  141 , here shown partly broken away. Hold down  141  does not in fact touch sleeves  810   d  and  810   p , only springs  811   d  and  811   p.    
     Distal bottom pin  860   i  rests on surface  632  of reset ring  630  (see FIG.  12 ). Proximal bottom pin  870   i  rests on surface  732  of trigger means  730 . Pop-up  850  has already been triggered, as shown also in FIG.  1 . 
     Bottom pins  770   i  and  870   i , when these pins&#39; respective pop-ups are pressed flush with face  121 , as happens when the pop-ups are pressed in to be reset, i.e. rearmed, drop into their respective trigger apertures  740  and  840 . When the proximal cylindrical wall of a pop-up&#39;s trough encounters a proximal pin-sleeve as the pop-up is being pressed in for resetting, the proximal pin-sleeve prevents the pop-up from being pressed in still farther, and the spring within the pin-sleeve pushes the upper pin down into the proximal bore in the pop-up (preview FIG.  25 ). After pins  770   s  and  870   s  have been pushed down into bores  721  and  821  of their respective pop-ups, forward motion by these pop-ups is obstructed. This pin action, namely of lockably arming the po-pups, is the sole function of the proximal pop-up pins. 
     A comparison of FIGS. 5,  8 , and  11 - 13  with FIG. 15 reveals that trigger means  830  is free to turn beneath both the pop-ups, plateau  831  and core tumbler  28  (preview FIG. 19) passing immediately behind blocking portion  854  of pop-up  850 . Trigger means  730  is also free to turn under pop-up  850 , however it is blocked in FIG. 15 by blocking portion  754  of pop-up  750  (see FIGS. 6-8) from turning beneath pop-up  750  (preview FIG.  35 ), because pop-up  750  is armed. Reset means  630  never encounters blocking portions  754  or  854 , and thus is always free to turn under both pop-ups. However its plateaus may encounter the bottom pin of an already triggered and extended pop-up (preview FIG.  35 ), here  860   i . The plateaus of reset means  630  do not fully extend across ring  630 , but only somewhat beyond the center line (see also FIG.  12 ). This is to prevent these plateaus from running into blocking portion  854  of pop-up  850  when pop-up  850  is in its armed position. Line  43 — 43  is the center line of pins  760   s  and  860   s , and these pins&#39; associated sleeves and springs. Reset plateaus  631   l ,  631   t , and  631   r  are always able to lift whichever of pins  760   i  and  860   i  rests currently upon surface  632  of reset ring  630 , or to lift both pins. 
     FIG. 15 also nicely shows the chamfers of bores  733 ,  833 , and  633 , introduced in FIGS. 12 and 13. 
     FIG. 16 defines cross-sectional FIGS. 17-19, which are taken along line  17 , 18 , 19 - 17 , 18 , 19 . A-Key  600  is shown in lock  1 , just as it is in FIG.  17 . In FIG. 18 B-key  700  has been inserted into lock  1  instead, and in FIG. 19 M-key  800  has been inserted. The keys themselves are not cross-sectioned. 
     FIG. 17 shows A-key  600  having essentially octagonal grip  605 , blade  609  with flat, top and bottom surfaces  601  and  602 , warding cut  604 , and flat surface  603  which abuts face  212  of core  20  and is orthogonal to surface  601 . Line  608  is decorative. 
     Blade  609  has angular keycuts  627 ,  628 ,  626 ,  623   p , and  623   d  that communicate with tumblers  27 ,  28 ,  26 ,  23   p  and  23   d , respectively, in the usual manner. Each tumbler  27 ,  28  or  26  communicates with a top pin  25 , all five top pins being identical. Tumblers  23   p  and  23   d  and their top pins  25  are, separated by identical mid-pins  24  in order to generate additional combinations, in the usual manner. Identical tumbler springs  22 , retained by hold-down  131  by means of crimped tabs  132 , keep the tumblers pressed against their respective keycuts in key blade  609 . Unlike the tumblers and the two mid-pins, top pins  25  are asymmetric, in that their tops are crowned to meet springs  22 , while their bottoms are angled, like the symmetric, angular ends of the five tumblers. Given the lock-combination shown, only ring-like elements  300   p  and  630  will turn with core  20  when key  600  is turned. Key  600  will always turn ring-like element  630 , the reset ring, but may or may not turn either or both of plain rings  300   p  and  300   d . Key  600  never turns trigger means  730  or  830 . 
     FIG. 17 further shows that core  20  is retained in lock  1  by stop ring  221  and rear plate  50 . If core  20  were of uniform diameter, forcibly extracting it with a dent-puller would be relatively easy, inasmuch as only one tumbler might in fact retain core  20  (this would be the case for tumbler  27  in FIG.  18 ). The usual lock core has a flange surrounding its proximal end and a clip at its distal end that together retain the core in both directions. Lock  1  improves upon this arrangement by omitting the flange and clip altogether and instead retaining core  20  with the much-stronger combination of stop ring  221  and rear plate  50 . This also allows assembly of lock  1 . 
     FIG. 18 shows B-key  700  inserted Into lock  1  and having features, apart from keycuts  727 ,  728 ,  726 ,  723   p , and  723   d , that are identical to the features of A-key  600 , these identical features being numbered identically following the hundred&#39;s place. B-key  700  has in its essentially octagonal grip a punched letter B instead of an A as its distinct, identifying aperture. Note that, when B-key  700  is turned, ring-like element  730  will turn with core  20 . For B-key  700  and ring-like element  730 , which is the trigger ring for pop-up  750 , this will always be the case. B-key  700  may or may not turn either or both of plain rings  300   p  and  300   d . B-key  700  never turns trigger  830  or reset ring  630 . 
     FIG. 19 shows M-key  800  inserted into lock  1  and having features, except for keycuts  827 ,  828 ,  826 ,  823   p , and  823   d , and except for rounded grip  805 , that are identical to the features of A-key  600 , these identical features being numbered identically following the hundred&#39;s place. Rounded grip  805  has the letter M punched therein as key  800 &#39;s identifying aperture. The A, B and M keys are thus easily distinguished visually and tactilely. Note that, ring-like element  830  will turn with core  20  when M-key  800  is turned. For M-key  800  and ring-like element  830 , which is the trigger ring for pop-up  850 , this will always be the case. M-key  800  may or may not turn either or both of plain rings  300   p  and  300   d . M-key  800  never turns trigger  730  or reset ring  630 . 
     A consequence of placing triggers  730  and  830  back to back, a necessary placement if all of the keys are to remain rotatable regardless of the armed or shot-forward positions of the pop-ups, which is to say regardless of the current positions of blocking portions  754  and  854  (see FIGS. 5,  8 , and  15 ), is that a substantial gap arises between tumblers  27  and  28 , visible in FIGS. 17-19. The tumblers of lock  1  thus form an asymmetric, linear array. Hence it becomes possible to create a dummy keycut in each of lock  1 &#39;s keys, namely dummy keycuts  629 ,  729 , and  829 , respectively, which dummy keycuts may be varied in depth independently and over a substantial range. Anyone not thoroughly familiar with lock  1 &#39;s construction (and even then) will have a devil of a time picking it, not to mention doing so without triggering a pop-up. 
     FIG. 20 shows lock  1  with all pins and tumblers removed, so that tail-piece  90  shows through keyway  213 . The cut line  21 — 21  runs through a diameter of pop-up  850  and through the center of core  20 . 
     FIG. 21 is taken along line  21 — 21 . Core bores  270 ,  280 ,  260 ,  230   p  and  230   d , emptied of tumblers in order to avoid depicting arbitrary, tumbler cross-sections, are shown here for the sake of verisimilitude. In its armed position pop-up  850  actually would protrude very slightly beyond face  121 . This is because, as described above, pop-up pins  870   s  and  870   i  must be toleranced to slide freely. In the armed position, with spring pressure taking up the slack of available tolerances, actual contact will be made by bore  821  (see FIG. 3) pressing on pin  870   s  from behind, causing pin  870   s  to make contact with the proximal inner surface of sleeve  810   p . Sleeve  810   p  will in turn be pressed against the proximal side of its bore in lock  1 . 
     As shown in FIG. 21, pop-up  850  has momentarily been pressed back into lock  1  and is being held pressed in, with pins  870   s  and  870   i  and sleeve  810   p  thus free to center within their containments. The position of these elements in lock  1  is so arranged that pin  870   i , smaller in diameter than the tumblers, now lies a about in the middle of the U-shaped aperture of trigger  840 . Pin  870   i  will thus not make contact with surface  846 , even when bore  821  presses on pin  870   s  from behind, because the combined slack of the tolerances is smaller by a factor of 2 or so than the distance of pin  870   i  from face  846 . Thus, pin  870   i  will not bind against means  830  when lifted by either of the beveled faces  841  or  842  of trigger  840 . 
     FIG. 21 further shows that pocket  580  in rear plate  50  keeps spring  480  centered on pop-up  850 . Pocket  570  has the same effect on spring  470 . 
     FIG. 23 is analogous to FIG. 21, except that cut line  23 — 23  in FIG. 22 just bypasses the core bores. Pop-up  750  is prevented from moving farther forward by the contact of distal cylindrical wall  727  of trough  720  (see FIG. 6) with sleeve  710   d . Pin  760   i  has been driven down upon reset ring  630  by pin  760   s , which in turn is driven down by spring  711   d . Visible behind pin  760   i  is reset plateau  635   tl . Plateau  635   tl  is able to lift pin  760   i , allowing pop-up  750  to be reset (preview FIG.  43 ). 
     Sleeve pairs  710   d  and  710   p , lying between side walls  723  and  724  of trough  720  (see FIG.  6 ), prevent pop-up  750  from rotating. Sleeves  810   d  and  810   p  perform this same function for pop-up  850 , via side walls  823  and  824  of trough  820 . 
     FIG. 24 shows distal sleeve  710   d , pins  760   s  and  760   i , and spring  711   d  of pop-up  750  after pop-up  750  has been triggered. Sleeve  710   d  is lengthwise so toleranced that gap  717   d  arises between it and hold down  151 . Were gap  717   d  not present, hold-down  151  would press sleeve  710   d  down upon trough bottom  722  so that pop-up  750  could not slide forward freely when triggered. Gap  717   d  is thus essential, and is replicated in all: four sleeves. 
     The inside diameter of sleeve  710   d  is slightly less than the diameter of bore  729 , and the diameter of pin  760   s  is slightly less than the diameter of pin  760   i . These diameter relations insure that pin  760   s  will drive into bore  729  the instant before sleeve  710   d  stops distal cylindrical wall  727  of trough  720  from shooting farther forward. When pin  760   s  is inside bore  729  it locks pop-up  750  against being pressed in. After wall  727  and sleeve  710   d  have made contact, trigger means  730  will just clear blocking portion  754  of pop-up  750  (see FIGS.  6  and  15 ). Pop-up  750  will, however, already have locked the instant before this occurs. Indicator lock  1  thus cannot be defeated by turning, say, key  700 , keeping it pressed against pop-up  750 , all the while trying to let pop-up  750  slowly move forward against spring  470 , hoping just to sneak past blocking portion  754  and then quickly to press pop-up  750  back into lock  1 . In the moment when key  700  can turn past blocking portion  754 , pop-up  750  will already have locked. Exactly the same is true of pop-up  850  and key  800 . 
     The ends of sleeve  710   d  are rounded to permit pop-up  750  to slide easily underneath it. This rounding is replicated in all four sleeves. 
     Top pin  760   s  is crowned at both ends to permit pop-up  750  to slide easily underneath it when triggered, no matter which end of pin  760   s  gets pointed downwards during lock assembly. This crowning is replicated in all four pins  760   s ,  770   s ,  860   s , and  870   s.    
     Bottom pin  760   i  has beveled at both ends so that it can be lifted by the reset plateaus (preview FIG.  43 ). This beveling is replicated in all four pins  760   i ,  770   i ,  860   i , and  870   i.    
     FIG. 25 shows that the diameter relations with respect to distal sleeve  710   d  and pins  760   s  and  760   i  are replicated with respect to the proximal sleeve  710   p  and pins  770   s  and  770   i . These relations are all in turn replicated for pop-up  850 . As shown in FIG. 25, pop-up  750  has been pushed in as far as it will go while being reset. A portion of the thinnest section  107  of lock  1  (preview FIGS. 26 &amp; 27) is seen, as well. The distance of pin  770   i  from section  107  well exceeds the tolerance: slack that will be taken up when pop-up  750  comes under spring pressure. Pin  770   i  will thus not bind on section  107 . 
     Pins  760   s  and  860   s  and sleeves  710   p  and  810   p  are responsible for blocking movement of pop-ups  750  and  850 , respectively, into lock  1 . Similarly, pins  770   s  and  870   s  and sleeves  710   d  and  810   d  are responsible for blocking movement of pop-ups  750  and  850 , respectively, out of lock  1 . All of these elements, furthermore, remain under spring pressure, which tends to shear them. Thus, they should be strong, as should trigger means  730  and  830 . Stainless steel is these elements&#39; material of choice, extruded, drawn, or sintered. The remaining elements of lock  1 , apart from the springs, may be made of suitable brass alloys. Locks on exterior doors get exposed to rain. 
     FIG. 26 depicts lock body  10  and integrally formed flange  120  in order to show the placement of the lengthwise bores of lock  1 . Tom Bore  103  accepts the ring-like elements which ride upon core  20  and is very sightly greater than them in diameter. Bore  104  is very slightly greater in diameter than core body  220 . Pop-up bores  170  and  180  hold, respectively, pop-ups  750  and  850  within lock  1  and are toleranced to let the pop-ups just slide freely within them. Where pop-up bore  170  approaches closest to bore  104  is thinnest-section  107  of lock  1 . Section  107  is short, however. An analogous section  108  arises for pop- up bore  180  (see FIG.  27 ). 
     Bores  105  and  106  are threaded to accept screws  555  and  556  (see FIG.  2 ).  161  and  162  are little, hemispherical pockets seen best in FIG.  29 . 
     FIG. 27 shows asymmetrically spaced-apart, spring-and-pin bores  127 ,  128 ,  126 ,  123   p , and  123   d . Threaded bores  102  and  101  (see also FIGS. 2 and 26) are depicted for standard, lock, mounting screws. These bores start life as short, blind holes that are then drilled out and tapped. They can easily be made narrower if dedicated mounting screws are supplied with the lock. They are shown here in their closest approach to pop-up bores  180  and  170 . 
     FIG. 28 shows threaded bores  105  and  106  for screws  555  and  556 . 
     FIG. 30 shows rear plate  50 , which allows indicator lock  1  to be assembled. Bores  505  and  506  in rear plate  50  are for screws  555  and  556 . Locator dimples  561  and  562  fit in pockets  161  and  162 . Tail-piece  90  extends through bore  590 . Core rear portion  222  turns in cylindrical pocket  504 . Blind-hole pockets  570  and  580  position springs  470  and  480 . 
     FIGS. 31-33 show these feature in greater detail and add counter sinks  515  and  516  for cap-screws  555  and  556 . 
     In the rotation sequence of FIGS. 35,  37 ,  39 , and  41 , key  700  is respectively positioned as in the upper rotation sequence FIGS. 34,  36 ,  38 , and  40 , wherein FIG. 40 shows a nearly complete rotation. In FIG. 35 pop-up  750  is armed, with pin  770   i  seated in trigger aperture  740 . As key  700  is rotated counterclockwise beveled face  742  encounters beveled pin  770   i  and begins to lift it against spring  711   p . In FIG. 39, pin  770   i  has been lifted just sufficiently to allow pop-up  750  to shoot forward. Since pin  770   i  is beveled and pin  770   s  is crowned, pop-up  750  shears easily past their point of contact. Pop-up  750  glides underneath sleeve  710   p , with pin  770   i  ending up inside bore  170  (see FIG.  23 ), in the region of thinnest section  107  (see FIG.  27 ). Should pop-up  750  be held pressed in, tumbler  27  will be prevented from rotating by blocking portion  754  of pop-up  750 . Likewise, but in the opposite direction, plateau  731  will also be blocked from rotating. Both directions of rotation must be accounted for to insure that lock  1  may be substituted for any standard lock cylinder, regardless of application. 
     In FIG. 39, top pin  25  has begun to lower onto surface  732  of trigger  730 . Top pin  25  and tumbler  27 , as well as tumblers  28 ,  26 ,  23   p  and  23   d , all have the same diameter, this being greater than the diameters of pop-up pins  770   i ,  770   s ,  870   i ,  870   s , and  760   i ,  760   s ,  860   i  and  860   s.    
     In FIG. 41 pop-up  750  has been shot fully forward. Pin  25  has ridden up and over plateau  731 , bevel  7351  having come into contact with pin  25  first, lifting it. Pin  25  now extends into aperture  740 , from which it is lifted up by beveled face  742 . Since pin  25  and tumbler  27  share the same midline, beveled tumbler  27  will lift beveled pin  25  on encountering it, so that a complete core rotation may be achieved. Pin  25  is asymmetric, its top being crowned, so that it does not bind against spring  22 . 
     In the reset rotation-sequence of FIGS. 43 and 45, key  600  is respectively positioned as in the upper rotation sequence of FIGS. 42 and 44. In FIG. 43 pop-up  850  is shown shot forward, with pin  860   i  resting on surface  632  of reset ring  630 . The owner turns A-key  600  so that it aligns with the pop-up opposite to the one to be reset, aligning here with  750 , thus allowing a finger tip or penny to be pressed against extended pop-up  850 . Bevel  635   rl  of plateau  631   r  lifts pin  860   i  until it rides up onto top surface  634   r , as in FIG.  45 . Pop-up  850  may now be pressed back into bore  180  until it locks into armed position. Pin  860   i  will come to rest on surface  332   p  of plain ring  300   p  (see FIG.  11 ). This rearming of pop-up  850  is entirely optional. A-key  600  will turn fully around whether or not the pop-up is reset, pins  25  and  860   i  riding up and down, over plateaus  631   l ,  631   t , and  631   r . This action will feel different, however, than if only one pin, namely pin  25 , rode up and down. Thus, the lock-owner receives an additional tactile cue that entry has been sought. The cue is delivered whether key rotation is clockwise or not, a quarter of a turn or more than that, because pin  860   i  rests between reset plateaus spaced about  450  apart. The same result obtains for pop-up  750 , or for both pop-ups together. 
     If the reset-procedure just described is attempted with key  700  or with key  800 , reset ring  830  will not rotate. The rotation neither of key  700  in lock  1  nor of key  800  in lock  1  permits a movement either of pop-up  750  or of pop-up  850  from the respective pop-up&#39;s extended, indicator, position back to its armed position. Only a rotation of key  600  permits such a movement. When to effect this movement remains optional. 
     FIG. 46 summarizes the key-functions of indicator lock  1 . 
     FIG. 47 depicts lock  2  and shows core  20 , single pop-up  750 , and tumbler  27 . Core  20 , pop-up  750 , and in fact all of the a tumblers of lock  1  get reused in lock  2  and thus they retain here their original numbering. However, only keys  600  and  700  get reused, key  800  having lost its raison d&#39;etre. 
     FIG. 48 shows lock  2  opened up as per FIG.  47 . Attached to body  12  is rear plate  52 , which now has but one pocket  2570  to hold and align spring  470 . Pop-up  750 , spring  470 , ring-elements  730 ,  630 ,  300   p , and  300   d  of lock  1 , plus sleeves  710   d  and  710   p , pins  760   s ,  760   i ,  770   s , and  770   i , and springs  711   d  and  711   p  of lock  1  all get reused in lock  2  and function exactly as they did in lock  1 . Although ring-element  830  no longer functions as a trigger means, it is kept here so that pin  770   i  can slide back onto surface  832  when pop-up  750  is armed. Similarly, reset means  630  no longer has to have plateau  631   r , there being no pop-up  850  to reset. That all of lock  1 &#39;s ring-elements are kept unchanged here is an acknowledgment of the economic likelihood that wasting a small amount of metal may be cheaper than purchasing new tooling. 
     FIG. 49 shows lock body  12 , similar to body  10 , but having only the one pop-up bore  2170  and one pop-up head  2150 . Body  12  has right and left facets  2113   r  and  2113   l , and right and left facets  2114   r  and  2114   l , of which only the last carries a pop-up head, namely  2150 . Pop-up head  2150  supports hold down  151 , reused from lock  1 , which it secures with tabs  2152 , exactly in the manner of body  10 . Tumbler head  2130  supports hold down  131 , reused from lock  1 , which it secures with tabs  2132 , exactly as in the manner of body  10 . Body  12  has threaded bores  2101 ,  2102 ,  2105 , and  2106 , which function exactly as bores  101 ,  102 ,  105  and  106  do in body  10 . Small hemispherical holes  2161  and  2162  function exactly as holes  161  and  162  function in body  10 . Body  12  has flange  2120 , which is similar to flange  120 , except that only one bore, namely bore  2170 , extends through flange  2120 . Pop-up bore  2170  holds pop-up  750  within lock  2  and is toleranced to let pop-up  750  just slide freely within it. Bore  2103  encloses the ring-like elements which ride upon core  20  and is very sightly greater than them in diameter, as before. Bore  2104  is very slightly greater in diameter than core body  220 , as before. Where pop-up bore  2170  approaches closest to bore  2104  is thinnest-section  2107  of body  12 . Section  2107  is short. 
     Lock  1  and lock  2  may both be easily built with metal stampings replacing the cast or sintered back plates  50  and  52 , respectively. 
     Since these and other changes and modifications apparent to one skilled in the art may be made in the herein described embodiments of the invention without departing from the scope and true spirit thereof, it is intended that all matter contained herein be interpreted in an illustrative, and not in a limiting, sense with respect to the invention claimed in the following claims and equivalents thereto.