BACKGROUND OF THE INVENTION
This invention relates to mechanical locks and, more particularly, to pushbutton combination locks.
In my copending application Ser. No. 153,526 filed on June 16, 1971, now U.S. Pat. No. 3,704,607 issued Dec. 5, 1972, there is described a pushbutton combination lock in which the deflection of a "zero-energy" control element at a prescribed time permits the outer door knob assembly to engage the inner knob assembly thereby to unlatch the door. A logic ladder, activator and a ratcheting arrangement are provided in conjunction with a dual scaffold assembly: (1) an opening scaffold to effect deflection of the control element when particular buttons in a set of pushbuttons are depressed and released in a "walking" manner and in a predetermined sequence or opening combination, but which disables the activator to prevent deflection of the control element at the prescribed time when any deviation from the strict sequence of the opening combination occurs, and (2) a reactivating scaffold to re-enable the activator and thus reactivate the lock when other pushbuttons are depressed and released in another predetermined sequence or reactivating combination.
While my foregoing invention represents a significant advance in the state of the art of combination locks, I have found that there is still room for improvement, especially where the lock is to be used on a vault or safe and high security is therefore required, or where for the sake of simplicity and reduced expense it is desired to eliminate the zero-energy control element so that rotary logic directly controls the knob assemblies, or where a sudden change in personnel dictates that in order to change the lock combination a special combination, known only to supervisory personnel, must be followed in order to gain access to the interior mechanism of the lock. In addition, my invention has for its objects one or more of the following:
1. to provide a combination lock with improved security;
2. to provide such a lock which utilizes a relatively simple opening combination;
3. to provide a combination lock having an opening combination and a reactivating combination either of which can be readily changed to a different combination without the use of tools;
4. to provide a memory of an unsuccessful attempt at "breaking" the combination;
5. to provide for deactivation of my pushbutton combination lock when any deviation from the opening combination or proper manipulation of the pushbuttons occurs;
6. to provide a pushbutton combination lock which can be readily used in the dark or by the blind;
7. to require a more complicated combination than the opening combination to reactivate my pushbutton combination lock after it has been deactivated.
SUMMARY OF THE INVENTION
These and other objects are accomplished in accordance with an illustrative embodiment of my invention, a high security pushbutton combination lock in which the depression of a particular subset of pushbuttons in accordance with a first or opening combination and in a "walking" manner causes the step-wise rotation of a control projection to a prescribed location and permits the outer door knob assembly to engage the inner door knob assembly thereby unlatching the door. Mounted along a common axis are a cylindrical stator, a cylindrical rotor resiliently coupled to and rotatably disposed within the stator and including the control projection extending radially therefrom, an annular logic collar affixed to or otherwise arranged to rotate with, the rotor, a circular apertured activator resiliently coupled to and rotatably disposed and axially slidable within the stator, and a ratchet in the activator responsive to a pawl on the rotor. The activator has an activated state, when the lock is normal, and a deactivated state, when the lock is disabled. Proper operation of each pushbutton in the opening combination causes one of a plurality of wedge-shaped steppers slidably disposed in the stator to urge against one of a plurality of wedge-shaped cams on the rotor, thereby causing the rotor to rotate in a step-wise fashion until the control projection reaches the prescribed location. Improper operation of a pushbutton, however, disables the lock in one of two ways: by causing a stepper to strike a nonapertured portion of the logic collar or by causing reverse rotation of the pawl against the ratchet. Both of the latter force the activator axially away from the logic collar and into its deactivated state.
One important feature of my pushbutton combination lock is that it increases its own security when an attempt is made to "break" the combination. When would-be combination "breaking" is detected, the lock becomes nonresponsive to its regular or opening combination and only the more complicated reactivating combination will open the lock and again render the lock responsive to its opening combination.
The measure of security, termed the security index, is the inverse of the probability of making the correct choice at each of all the option points during the input of the combination. For a nine-pushbutton lock in which four digits are used in the opening combination and six are used in the reactivating combination, the security index is increased from 4 billion to 30 million million when the lock switches from its opening four-digit combination to its reactivating combination. From the small number of digits used, my pushbutton combination lock wrests a security index which is many orders of magnitude higher than the mathematical number of combination normally derived from the same number of digits. Four base-nine digits written in the conventional manner generate a maximum of less than seven thousand combinations. However, my lock requires the four digits to be written in an overlapping or "walking" manner which has the effect of doubling the number of digits. Thus, instead of less than seven thousand, the number of possible combinations rises to forty-three million.
In addition, my pushbutton combination lock includes one or more of the following features:
1. Memory of an unsuccessful attempt at intrusion obtains by virtue of the automatic change of combination as mentioned above. Thus, when the regular combination is ineffective, an alert is signaled;
2. Both the combinations may be changed without the use of tools and in a surprisingly simple manner considering the very tight security. This feature is important when a sudden change in authorized personnel occurs;
3. The lock can readily be opened in the dark or by a blind user by virtue of the simple pattern of the pushbuttons which facilitates identification by touch;
4. Traditional combination "breaking" by "feel" is impossible with this lock since it uses to tumblers or fence. The components of the logic system are very light with no detectable "feel." The element which controls the opening operation performs no work and requires only a minute amount of energy to move it between its two positions. Therefore, "feel" provides no alternative short cut to random trial and error against staggering odds; and
5. The same general principles can be used in an ultra high security lock for applications such as a safe or vault. The chief difference would be in size, ruggedness and precision of the components. Another departure would be in the use of six digits for the opening combination, for which provision is made as described hereinafter. The security indexes become 30 million million for the opening combination and 200 million billion for the reactivating combination.
BRIEF DESCRIPTION OF THE DRAWING
The above and other objects of my invention, together with its various features and advantages, can be easily understood from the following more detailed discussion, taken in conjunction with the accompanying drawings, in which:
FIG. 1A is the outer view of a pushbutton door lock;
FIG. 1B is an exploded view of one embodiment of my invention;
FIG. 2 shows the cable interconnection between the steppers and the pushbuttons;
FIG. 3 is a sectional side view of a typical pushbutton;
FIG. 4 is an isometric view of the stator showing the open end into which the rotor is inserted;
FIG. 4A is a side view of axial projection member 45 of stator 10;
FIG. 5 is an isometric view of the stator showing its drumhead end and taken along line 5--5 of FIG. 4;
FIG. 6 is an isometric view of the rotor showing the end adjacent the logic collar;
FIG. 7 is an isometric view of the rotor showing the end which is inserted into the stator and taken along line 7--7 of FIG. 6;
FIG. 8 shows a torsion coil spring which fits within the rotor;
FIG. 9 is an isometric view of a retaining nut which holds the rotor rotatably within the stator;
FIG. 10 is a plan view of a logic collar which is affixed to the rotor;
FIG. 11 is an isometric view of an activator the stem of which is slidably mounted in the stator;
FIG. 12 is an isometric view of spring means which couple together the stator and the activator;
FIG. 13 is an enlarged view of the ratchet area of the activator of FIG. 11;
FIG. 14 is a straightened-out sectional view through the teeth of the ratchet and taken along line 14--14 of FIG. 13;
FIG. 15 is a cross-sectional view of a typical tooth of FIG. 13;
FIG. 16 is a top view of the inner and outer door knob assemblies and the associated means for interlocking their actions;
FIG. 17 is an inward-looking view taken along line 17--17 of FIG. 16;
FIG. 18 is a centripetal view of the control elements of FIG. 17 taken along line 18--18 of FIG. 17;
FIG. 19 is a diagram showing the cams and steppers in the planar equivalent of the cylindrical rotary logic used in my invention;
FIG. 20 is a diagram, as in FIG. 19, showing how the overlap or "walking" manipulation produces a definite intermediate step or option point in the writing in of the combination;
FIG. 21A is a sequence chart which describes the input of four digits of the regular combination up to the point where the fourth pushbutton is held. In addition the chart indicates alternative options at each step in the sequence;
FIG. 21B continues the sequence chart showing how manipulation of the knob becomes a part of the combination. The chart also shows the unlocking operation and the return to normal;
FIG. 21C is a continuation of sequence chart of FIG. 21A for an opening combination of six digits;
FIG. 21D is a sequence chart which shows how deactivation occurs as a result of deviations from the regular combination as indicated in FIGS. 21A, 21B and 21C;
FIG. 21E is a sequence chart showing the combination which is required to reactivate the system. The chart also shows the alternative options which result in failure to reactivate;
FIG. 21F shows how FIGS. 21A and 21B should be arranged to show the complete sequences for an opening combination using four digits;
FIG. 21G shows how FIGS. 21A, 21C and 21B should be arranged to show the complete sequence chart for an opening combination of six digits;
FIG. 21H shows how FIGS. 21E, 21A and 21B should be arranged to show the complete sequence chart for the tight combination which is required when the opening four-digit combination is not effective;
FIG. 21I shows how FIGS. 21E, 21A, 21C and 21B should be arranged to show the complete sequence chart for the tight combination which is required when the opening six-digit combination is not effective;
FIG. 21J shows how FIGS. 21A, 21B and 21D should be arranged to show deactivation and all possibilities which may cause it when arranged for a four-digit opening combination;
FIG. 21K shows how FIGS. 21A, 21C, 21B and 21D should be arranged to show deactivation and all possibilities which may cause it when arranged for a six-digit opening combination;
FIG. 22 is a diagram showing the cams and steppers in the planar equivalent of cylindrical rotary logic based on an illustrative embodiment of my invention having only six pushbuttons and using an opening combination of only three digits; and
FIG. 23 is a six pushbutton equivalent of FIG. 1.
Turning now to FIG. 1A, there is shown the outer view of a typical pushbutton lock as it might be used on a door. For certain applications a handle may be preferred to the knob 50. Illustratively, nine pushbuttons 1 are provided for writing in the opening and reactivating combinations. The buttons are typically not designated, but are arranged in a simple pattern which facilitates identification in the dark or by the blind. The button arrangement has a further advantage in that a seemingly different set of combinations may be issued to each of a number of authorized users. Each would have a different numbering pattern as a base for his combinations. Two sets of numbering designations -- one through nine or zero through eight -- may, for example, each be arranged left to right from top to bottom, or top to bottom from left to right, or bottom to top from left to right, or peripheral-wise ending or starting with the center.
FIG. 1B is a partially exploded view of an illustrative embodiment of a pushbutton combination lock in accordance with my invention. Arranged along a common axis are the following components: (1) a cylindrical stator 10, (2) a coil spring 17, (3) a cylindrical rotor 3 rotatably disposed on hollow shaft 19 of stator 10, (4) a retaining nut 18 which screws onto shaft 19 thereby preventing rotor 3 from disengaging stator 10, (5) a disc-like logic collar 21 affixed along its inner rim 21a to surface 71 of rotor 3, and (6) a circular activator rotatably mounted with shaft 15 in hollow shaft 19. As will be described more fully hereinafter, each pushbutton is a cable coupled to a wedge-shaped stepper 2 slidably mounted in stator 10, and both rotor 3 and activator 13 are arranged to control the interlocking of door-knob assembly 75.
Each of the foregoing components will now be described more fully with reference to FIGS. 2-19.
As shown in FIG. 2, a typical stepper-pushbutton assembly comprises a flexible control cable interconnecting a stepper 2 and compressive spring 27 of pushbutton 1. The cable comprises a sheath 29, push-pull core 30, winged ring 28 and compressive spring 27. Sheath 29 is attached at the input end 29a to winged ring 28 and at the output end 29b to the drumhead end 10a of stator 10. The push-pull core 30 connects the tip at the input end directly to the stepper 2 at the output end. The stepper 2 illustratively has a square cross-section and wedge-shaped end 2a adapted to advance rotor 3 (via cam 5 or cam 6 as described hereinafter). The input end 29a of the cable, comprising spring 27 and ring 28, is insertable into the socket on the inward side of the pushbutton 1, as seen in FIG. 3, and is held in place by conventional means such as a detent or by misaligning the wings of ring 28 with notches 69. As will become more apparent from the operation section of this description, spring 26 is compressed when the associated stepper is blocked at midpoint awaiting release of the previously operated stepper. When the previously operated stepper recedes, spring 26 further compresses spring 27 and also further advances the associated stepper. These steppers are slidably disposed in stator 10 as shown in FIG. 1B.
The stator 10, shown in greater detail in FIGS. 4 and 5, comprises a cylindrical shell coaxial with an inner cylindrical tube or hollow shaft 19. The inner surface of the shell has nine channels 11A-I of rectangular cross-section which act as guides for the corresponding steppers 2A-I. The channels are circumferentially spaced parallel to the cylindrical axis of the stator. The drumhead end 10a of stator 10, shown in FIG. 5, has thereon nine attachment locations 80A-I for the nine control cables 29A-I. As shown in FIG. 4A, on the outer surface of the shell are an axial projection 45 and a radial projection 48. The former has a pair of axially directed flat surfaces (or catches) 23 and 44a joined by an oblique surface 44.
The cylindrical rotor 3, shown in FIGS. 6 and 7, fits into the annular cavity 70 of stator 10, and comprises a cylindrical outer shell 3a and a coaxial inner cylindrical tube 39 which extends through the base or annular surface 71 (FIG. 6). The annular cavity 38 formed between outer shell 3a and inner tube 39 holds spring 17. On the outer surface of shell 3a are cams 5-9 dimensioned so that rotor 3 fits rotatably within cavity 70. Each cam comprises a wedge-shaped member having an oblique surface with all such surfaces being oriented in the same direction as each other and arranged to be acted on by the oblique surfaces of the ends of steppers 2 so that the force of a stepper on cam causes the rotor to rotate in the direction of the arrow. For reasons which will later become apparent, the oblique surfaces of cams 5 and 6 are longer than those of cams 7, 8 and 9. Note that each stepper 2 is contained partly by its corresponding channel 11 and partly by tangential slidable contact with the outer cylindrical surface of shell 3a of rotor 3. Arm 16, which projects radially from the rotor at cam 6, normally abuts against surface 24 of axial projection 45 on stator 10 and initially has its edge 16a positioned at step 22 (FIGS. 1B, 19). The sum of the angular dimensions of a stop cam (7 or 8) and a stepper 2 should be equal to one angular step or ten degrees. For reactivation purposes later described, rotor 3 also has a resilient finger 12 affixed to the bottom of cam 9. Finger 12 is circumferentially directed oppositely to that indicated by the arrow on rotor 3 of FIGS. 1B and 6.
The torsion coil spring 17 which interconnects stator 10 and rotor 3 is shown in FIG. 8. The spring is contained by annular cavity 38 in rotor 3 with terminal 36a attached to rotor 3 at point 36 (FIG. 6) and terminal 35a attached to the stator 10 at the point 35 (FIG. 5). The arrow in FIG. 8 shows the direction in which the spring 17 urges terminal 36a so that rotor arm 16 is normally urged against stop 24 on stator 10. FIG. 9 shows a retaining nut 18 which after rotor 3 is in place over tubular shaft 19, is screw-fastened to the threads on the end of shaft 19. The annular surface 71 of rotor 3 (FIG. 6) has a countersunk cavity 20 which allows nut 18 to fit flush with the annular surface 71.
Shown in FIG. 20 is an annular logic collar 21 of thin sheet material which is attached, along its resilient inner rim 21a only, to the annular surface 71 of rotor 3. The collar illustratively has three apertures 41, 42 and 43 angularly spaced from one another but at the same radial distance from the center of the collar (i.e., from the common axis). More specifically, the collar 21 has a larger outer diameter than that of rotor 3 so that certain ones of the steppers, when properly operated, slide along the outer surface of rotor 3 and penetrate these apertures. Thus, the collar 21 rotates with the rotor 3 while riding on the spidery surface of activator 13 to be described next. When a pushbutton is improperly depressed, the tip of the corresponding stepper 2 impinges on a nonapertured portion of collar 21 so that the force caused by the stepper is transmitted to activator 13. Aperture 42, on the other hand, allows for valid stepper penetration between cams 6 and 8. Aperture 43 allows for valid stepper penetration between cams 5 and 7. The function of aperture 41 will be described with reference to FIG. 19. The arrow in FIG. 10 indicates the direction of stepwise rotation of collar 21 in response to the input of a combination. Note that the inside diameter of collar 21 must be greater than or equal to outer diameter defined by ratchet 31, otherwise collar 21 must include an aperture to permit pawl 4 to engage ratchet 31.
As mentioned previously activator 13, shown in FIG. 11, comprises a rigid spidery disc mounted on a stem or shaft 15 which fits slidably into axial cavity 37 within shaft 19 of stator 10. As with collar 21, the outer diameter of activator 13 is larger than that of rotor 3 so that a plurality of aperatures, 22 and 67, can be located in the outermost portions at a radial distance which permits the steppers 2 to penetrate therethrough. The activator 13 also includes a curved ratchet arrangement 31 and a pair of angularly spaced radial arms 14 and 46 described hereinafter. Apertures 22 allow valid penetration of steppers which have penetrated apertures 42 and 43 of collar 21. Aperture 67 is used with aperture 41 of collar 21 to reactivate the lock once disabled and will be explained later. Nonapertured area 72 detects penetration of stepper 2I into aperture 42 of collar 21. Arm 14 is used with a regular four-digit combination and when the lock is in its normal stae is positioned so that its edge 14a is at step 29 (FIG. 1B, 19). When a six-digit combination is used, arm 14 is located at the position shown at 14'. The arrow in FIG. 11 shows the direction of step-wise rotation and also the direction in which the activator rotates during deactivation. Arm 46 is connected through a retractible spring 47 to arm 48 of stator 10 as shown in FIGS. 1B and 12. In the activated position, arm 46 is urged against catch 23 of stator 10. A component of the spring force urges the activator against collar 21 and, in turn, against rotor surface 71. If the activator is forced away from the rotor, arm 46 disengages from catch 23. Spring 47 then urges arm 46 along oblique surface 44 to stop 44a. In this manner the activator is toggled between the two stable conditions of activation and deactivation.
The improper release of a pushbutton is detected by a ratchet arrangement shown in FIGS. 1B, 11 and 13-15. FIG. 13 shows an enlarged view of ratchet 31 of activator 13. FIG. 14 is a straightened-out sectional view through the teeth of the ratchet of FIG. 13, whereas FIG. 15 is a cross-sectional view of a typical tooth to FIG. 13. Pawl 4, shown in FIG. 6, with its tip trailing, rides up the toothed channel 31a. The pawl returns, with the tip leading, down the return channel 34, thus completing a circuit during a normal operation. The dots, indicated by step numbers, show the spot where the pawl tip comes to rest at the end of each step. The dividing ridges 32 and 33 are arranged to cause the centripetal component of the pawl to gradually build up as the pawl is moved up the toothed channel 31a. At step 8 the contours are such that the pawl tip bears against the end of dividing ridge 33 and if travel is reversed, the pawl tip switches to channel 34. Channel 34 becomes progressively more shallow from the tip of ridge 33 to the lower end of ridge 32. Dividing ridge 32 is arranged to cause the centrifugal component of the pawl tip to gradually build up as the pawl returns. As step 0 is approached to pawl tip descends sidewise to the designated spot, thus switching to the starting point for the next operation. At step 8 the pawl tip is ready for normal travel in either direction. At step 12 a channel switch is also made. When the regular combination uses six digits (as for a safe or vault) dividing ridges 32 and 33 are arranged to be continuous at step 8. When reversal takes place at any step other than a switchover point, travel is arrested by the tooth causing a force buildup which pushes the activator away from the rotor causing arm 46 to disengage switch catch 23. Spring 47 then urges arm 46 along surface 44 thus causing the activator to further separate from rotor surface 71 and provide clearance for the pawl tip as it is returned over the remaining teeth to normal at step 0. As arm 46 moves to stop 44a, arm 14 moves control element 66 to the position where interlock between the outer and inner knobs is impossible, as described hereinafter with reference to FIGS. 16-18.
More specifically, FIG. 16 is a top view of the outer knob 50, the inner knob 51 and the associated means of controlling and interlocking their actions. The inner knob is connected to arm 52 at the end of which is an engaging member 53. The outer knob 50, acting through torque limiter 54, rotates arms 55 and 56. The limiter 54 prevents internal damage which might otherwise be caused by application of a tool to the outer knob. Arm 55 is a rigid member which serves as a back stop for arm 56. The latter is tensioned lightly against arm 55 and the two are arranged to maintain a constant angular relationship to each other. Arm 56 is of thin reedlike material which is capable of transmitting high rotational torque while yet being susceptible of deflection in the outward direction by a light force bearing on bow-shaped member 58 located at its outer extremity. An engaging member 57 is disposed on arm 56 in radial alignment with similar member 53 on arm 52 so that member 57 can contact either side of member 53 thus causing the inner knob 51 to be interlocked and rotated by the outer knob 50. The means by which the inner knob withdraws the latch (not shown) are conventional arrangements well known to those skilled in the art and are not shown in the interest of simplicity. The radial and angular positions of the foregoing components are shown in FIG. 17, an inward-looking view of FIG. 16. Included are the control arrangements with outer knob arm 56 shown in its normal position with engaging member 57 against stop 60. The phantom view shows arm 56 at off-normal stop 61 which is reached when engaging member 57 is made to bypass engaging member 53 in a manner to be described later. The inner knob arm 52 is shown in its normal position in angular alignment with control element 66 whose function is also described below. FIG. 18 is a centripetal view of the control elements of FIG. 17 with line 62-63 straightened out. This figure shows how arcuate member 58 is controlled indirectly by logic output projection arm 14 of activator 13 and arm 16 of rotor 3. Normally, arcuate control element 66 is in the position shown with its supporting arm 65 resting against activator arm 14. The phantom view 58' shows how the bow-shaped member is not affected as it moves along the line toward 63. However, if arm 16 is brought up to the position indicated by 16', control element 66 is moved to position 66'. Consequently, arcuate member 58 is deflected and rides over element 66 in the outward direction. In this latter case engaging member 57 of arm 56 of FIG. 17 would bypass member 53 of arm 52. While bow-shaped member 58 is at the 63 end of the line, rotor arm 16 and, in turn, control element 66, are restored to normal. When bow-shaped member 58 is returned, it is not deflected as before and, as a result, member 57 of arm 56 engages member 53 and carries along arm 52 thus effecting opening of the door. As outer door knob rotation continues and causes arm 56 to return toward end 62, member 58 rides outwardly over arcuate deflector 59 causing engaging members 57 and 53 to disengage. Thus, arm 52 is permitted to return to angular alignment with element 66.
The operation of my invention in response to an opening combination and, when disabled, to a reactivating combination will now be described with reference to FIGS. 19-21.
In FIG. 19 the steppers and cams, which actually engage along longitudinal axes on the rotor 3 or stator 10, are shown disposed radially for the purposes of explanation. That is, FIG. 19 is the planar equivalent of the cylindrical rotary logic used in my invention. The circle is shown divided into 30-6, 10-degree arcuate segments which are numbered to designate the various rotary positions of the rotor 3. Only the steppers and cams are shown, however, since their interaction is basic to the logic employed herein. The cams 5-9 move as a unit in circular fashion about the center. The steppers 2A-I may advance toward and resede away from the center while maintaining a fixed radial position. The rotor is in the normal position when the radial side 5a of cam 5 points to the step designated 0. The maximum rotational travel of the cams is eight steps for a regular combination of four digits, or 12 steps for a regular combination of six digits.
When stepper 2A advances on cam 5, the rotor is advanced two steps. Cam 6 is then in position to be acted on by stepper 2B. With stepper 2A fully advanced into the gap between cams 5 and 7, stepper 2B is advanced on cam 6 causing further rotation of the rotor to step 3. At this point, stepper 2A stops cam 7 thus arresting rotation of the rotor. Stepper 2B has not completed its advance on cam 6. This condition is shown by FIG. 20. When stepper 2A recedes, releasing cam 7, stepper 2B resumes its advance on cam 6 and rotates the rotor to step 4. Stepper 2C then advances on cam 5 rotating the rotor to step 5 where stepper 2B stops cam 8. Stepper 2B then recedes releasing cam 8, allowing stepper 2C to resume its advance on cam 5 and rotate the rotor to step 6. Stepper 2D then advances on cam 6 rotating the rotor to step 7 where stepper 2C stops cam 7. Stepper 2C then recedes releasing cam 7, allowing stepper 2D to resume its advance on cam 6 and rotate the rotor to step 8. The cams 5-8 are now in the positions indicated by phantom views 5'-8'. For a four-digit combination, stepper 2E would have position and aspect in phantom view 2E' so as not to affect cam 5. For a six digit combination steppers 2E and 2F would continue the rotor rotation to step 12 in a manner similar to the above. The position and aspect of of stepper 2H is such that cam 5 will not be affected by advance of stepper 2H
Steppers 2G, 2H, 2I and cam 9 are not used in the regular (opening) four or six digit combinations. Stepper 2G and cam 9 are used, however, to reactivate the system. More specifically, deactivation occurs whenever improper pushbutton operation causes activator 13 to disengage stator 10, i.e., arm 46 on activator 13 disengages catch 23 and slides down surface 44. To reactivate the lock, stepper 2A advances on cam 5 rotating the cams to step 2. Cam 9 is now in phantom position 9'. Stepper 2G then advances, depressing resiliently mounted reactivating finger 12 on rotor 3 (FIG. 6) through aperture 41 of logic collar 21 (FIG. 10) into aperture 67 of activator 13 (FIG. 11). Stepper 2A then recedes allowing the cams to return briefly until cam 9 is stopped by stepper 2G. During this brief travel the tip of the depressed reactivating finger 12 engages rib 40 of activator 13 shown in FIG. 11. Stepper 2G then recedes releasing cam 9. Spring 17 (FIG. 8) now returns the rotor 3 to normal at step 0. In so doing resilient finger 12 rotates the activator counter to the urging of spring 47 (FIG. 5) until arm 46 on activator 13 reengages catch 23 on stator 10. Reactivation is then complete. Finger 12 remains engaged until the next normal usage when it is disengaged from rib 40 as cam 9 is rotated off normal.
The manner in which the overlap or "walking" manipulation of pushbuttons produces a definite intermediate step or option point in the writing in of the combination is best understood with reference to FIG. 20. By virtue of this feature the security index is increased by many orders of magnitude. The major component of the regular combination consists of four (or six) digits written on the nine pushbuttons. Normally four base-nine digits means only four points at each of which there are nine options in the choice of the next digit. Such a procedure results in less than 7,000 possible combinations. However, overlap operation has the effect of doubling the number of option points as can be verified in the sequence chart of FIG. 21A. Consequently, the number of possible combinations is increased to 43 million. The generation of the intermediate option point is illustrated by FIG. 20 which shows the stepper-cam relationship that obtains at step 3. After stepper 2A is fully advanced on cam 5, moving the rotor to step 2, stepper 2B advances on cam 6 further moving the rotor to step 3 where cam rotation is arrested as cam 7 impinges on stepper 2A. As shown in FIG. 20, stepper 2B has moved cam 6 only halfway. At this point there are nine options as shown in the sequence chart. Any of the remaining seven steppers may be advanced, but this would result in deactivation by impingement of the stepper tip on the logic collar 21 which in turn pushes activator 13 into its deactivated state. If stepper 2B recedes, the cams return to step 2. The resulting reversal causes pawl 4 to exert a deactivating push on the ratchet 31. The ninth and remaining option is the receding of stepper 2A which releases cam 7 and allows stepper 2B to continue its advance on cam 6 and move the rotor to step 4.
An alternative embodiment of my invention using only six pushbuttons instead of nine is shown in FIG. 23. The corresponding planar equivalent of cylindrical rotary logic based on this arrangement using a regular combination of only three digits is shown in FIG. 22. This scheme trades off a portion of the security index for gains in simplicity and compactness. Only the spacing of stepper 2F is irregular. The channel for 2F lies between steps 16 and 16 1/2 instead of between 15 1/2 and 16. This location of stepper 2F prevents the possibility of interference when cam 6 reaches step 16. This arrangement uses the same regular sequence up to step 6 as is shown in FIG. 21A and the same reactivating sequence as is shown in FIG. 21E except that pushbutton 1F and stepper 2F replace pushbutton 1G and stepper 2G, respectively. Since logic collar 21 would be apertured between cams 6 and 8, the activator 13 should not be apertured at step location 6-8 in order to insure deactivation if stepper 2E intrudes between cams 6 and 8. Steppers 2D and 2E should never be advanced, otherwise deactivation occurs. The security index, although lower than for this four-digit base-nine arrangement is nevertheless competitive with conventional locks. More specifically, the security indexes of the six button-three digit arrangements are 2.6 million (opening) and 3.3 billion (tight). For the nine-button-four digit arrangement the indexes are 4 billion (opening) and 30 million million (tight).
The detailed manner in which my invention responds to various combinations is described below with the help of the sequence charts shown in FIG. 21F-I. These charts are read from top to bottom. The broken column on the left shows the actions produced on a step-by-step basis when the opening combination is followed. The sequences to the right of the left-hand column show the various actions produced by deviations from the opening combination. In reading the chart, a dot at the bottom of a vertical line segment indicates that the action may progress from that line segment into any of the other line segments surrounding the dot. On the other hand, a dot at the top of a vertical line segment indicates that action on any of the other line segments surrounding that dot may progress into the vertical line segment. Furthermore, an x indicates a device is operated or is moved in a direction away from its normal condition. A perpendicular bar indicates the device is released or is moved toward its normal condition.
The combination for opening the lock assembly and the results produced thereby comprise: depressing pushbutton 1A, the pushbutton to which cable A is assigned, causes stepper 2A to advance along channel 11A in stator 10 and, bearing on cam 5, causes rotor 3 to move to step 2. While holding pushbutton 1A down to prevent spring 17 from rotating rotor 3 back to normal (step 0), pushbutton 1B is depressed causing stepper 2B to advance on cam 6 and to rotate the rotor 3 to step 3 where cam 7 is stopped by stepper 2A. Pushbutton 1B is held as pushbutton 1A is released. Stepper 2A in turn recedes, releasing cam 7. Stepper 2B then resumes its advance under urging from spring 26 and rotates rotor 3 to step 4. Pushbutton 1B is still held as pushbutton 1C is depressed causing stepper 2C to advance on cam 5, rotating rotor 3 to step 5 where cam 8 is stopped by stepper 2B. Pushbutton 1C is held as pushbutton 1B is released, withdrawing stepper 2B which releases cam 8. Stepper 2C urged by spring 26 continues on cam 5 to rotate rotor 3 to step 6. Pushbutton 1C is still held as pushbutton 1D is depressed causing stepper 2D to advance on cam 6 and rotate rotor 3 to step 7 where cam 7 is stopped by stepper 2C. Pushbutton 1D is held as pushbutton 1C is released, causing stepper 2C to recede and release cam 7. Stepper 2D urged by spring 26 resumes its advance on cam 6 and rotates rotor 3 to step 8, the final step for the arrangement using a four-digit regular combination.
When the regular combination uses six digits the sequence continues thus: while holding pushbutton 1D, pushbutton 1E is depressed causing stepper 2E to advance on cam 5 and rotate rotor 3 to step 9 where cam 8 is stopped by stepper 2D. Pushbutton 1E is held as pushbutton 1D is released, causing stepper 2D to recede and release cam 8. Stepper 2E urged by spring 26 resumes its advance on cam 5 and rotates rotor 3 to step 10. Pushbutton 1E is still held as pushbutton 1F is depressed causing stepper 2F to advance on cam 6 and rotate rotor 3 to step 11 where cam 7 is stopped by stepper 2E. Pushbutton 1F is held as pushbutton 1E is released, causing stepper 2E to recede and release cam 7. Stepper 2F urged by spring 26 resumes its advance on cam 6 and rotates rotor 3 to step 12, the final step for the arrangement using a six-digit regular combination.
As the rotor 3 moves to the final step (8 or 12) the tip of pawl 4 descends sidewise in ratchet arrangement 31 (FIG. 13) to the point where the pawl is ready to return with the tip leading to step 0 via ratchet channel 34. As shown in FIGS. 17 and 18, rotor arm 16 moves control element 66 from its normal position against activator arm 14 to its active position against stop 64. The final pushbutton (1D or 1F) is still held and outer knob 50 (FIG. 16) is rotated moving the outer knob arm assembly with member 49 following line 62-63 (FIGS. 17-18). Bow-shaped member 58 rides over arcuate deflector 59 without effect. Bow-shaped member 58 also rides over control element 66 causing deflection of arm 56 and causing engaging member 57 to bypass engaging member 53. The final pushbutton is then released causing stepper 2D or 2F to release cam 6 and in turn allow rotor 3 to return to step 0 under the urging of spring 17. Concurrently, pawl 4 rides down ratchet channel 34 (FIG. 13). The channel is so contoured that the tension in the pawl builds up gradually so as to facilitate the switch to the step 0 point at the beginning of the toothed channel. Rotor arm 16 withdraws and allows control element 66 (FIG. 18) to return to its normal position against activator arm 14. At this time the outer knob 50 (FIG. 16) is returned toward its normal position. As shown in FIGS. 16-18, with control element 66 back to normal, bow-shaped member 58 is not deflected thereby allowing engaging member 57 to engage member 53 causing inner knob arm 52 to be carried along by the outer knob arm 56. Unlocking occurs by means well known in the art, but not shown. As arm 56 continues, deflector 59 deflects bow-shaped 58 causing engaging member 53 of the inner knob arm 52 to be disengaged from engaging member 57 of outer arm 56 and to return to its normal position in angular alignment with control element 66. Outer arm 56 continues to its normal position with member 57 against stop 60. The lock system is then back to normal and remains activated.
If deactivation occurs at any time before the outer knob is returned during the final unlocking operation, unlocking by the regular combination cannot be effected. FIGS. 21J and 21K shows all possible sequences which cause deactivation. These are the options which depart from the left hand column in FIGS. 21A, 21B and 21C. The left hand column shows the sequence chart for the normal use of the regular combination. The options toward the right lead to the deactivating sequence of FIG. 21D. Deactivation occurs upon the occurrence of any of the following events:
1. A pushbutton not used in the regular combination causes the advance of its associated stepper which, by impinging on the nonapertured portion of collar 21, pushes activator 13 off of catch 23.
2. A pushbutton which is used in the regular combination, but which is depressed before or after its valid point in the sequential order, causes deactivation by striking the nonapertured portion of collar 21 as in (1) above.
3. A pushbutton depressed in accordance with the regular combination, but which is released before the succeeding pushbutton is depressed, causes reverse rotation of the rotor under the urging of spring 17 and in turn causes pawl 4 to push the ratchet portion of the activator 13. Consequently, activator 13 is pushed off catch 23.
4. A pushbutton depressed in accordance with the regular combination which is released before the preceding pushbutton is released, causes partial reverse rotation of the rotor and in turn causes pawl 4 to push the ratchet portion of the activator as in (3) above. As the activator 13 is forced away from the rotor 3, arm 46 disengages catch 23 of the stator 10. Urged by spring 47, the activator 13 rotates and moves farther away from the rotor as arm 46 moves along surface 44 to stop 44a. Arm 14 moves inwardly (FIG. 18) against supporting arm 65 thereby moving control element 66 to its active position 66' against stop 64 where the bow-shaped member 58 on arm 56 is deflected and interlock between outer and inner knob mechanism is impossible. The lock is now nonresponsive to its regular combination.
With the system deactivated as described above, it will be responsive only to the tight combination which consists of a two digit reactivating combination followed by the opening combination. The sequence chart of the reactivating combination is shown in FIG. 21E. Pushbutton 1A is depressed causing stepper 2A to advance on cam 5 and move rotor 3 to step 2. While holding pushbutton 1A, pushbutton 1G is depressed causing stepper 2G to advance. The toe of stepper 2G, penetrating aperture 41 of collar 21, depresses the resilient reactivating finger 12 into aperture 67 of activator 13. Pushbutton 1G is held as pushbutton 1A is released causing stepper 2A to recede from cam 5. Rotor 3, urged by spring 17, returns until cam 9 is stopped by stepper 2G. The tip of reactivating finger 12 is now in position to engage activator rib 40. Pushbutton 1G is then released, withdrawing stepper 2G which releases cam 9 thus allowing rotor 3 to continue back to step 0. Reactivating finger 12, engaged with rib 40, rotates activator 13 to normal where arm 46 reengages catch 23 if all pushbuttons and steppers are normal. The lock is now reactivated and will be responsive to the remainder of the tight combination which is the same as the regular combination previously described. Reactivating finger 12 will be released from rib 40 as shown as rotor 3 advances from step 0. The tight combination differs from the opening combination in three important respects: (i) the tight combination has two more digits, (ii) the tight combination reuses one of the pushbuttons a second time, and (iii) the tight combination has a pause during pushbutton manipulation when no pushbutton is is depressed.
It is to be understood that the above-described arrangements are merely illustrative of the many possible specific embodiments which can be devised to represent application of the principles of my invention. Numerous and varied other arrangements can be devised in accordance with these principles by those skilled in the art without departing from the spirit and scope of the invention.