Patent Grant
8667821
This invention is related to mechanical combination locks. In more specificity, the invention relates to resistant mechanical combination locks and improvements thereto (generally referred to herein as the “locking system”).
In many technical arts, mechanical devices have been superseded by their electronic digital counterparts. The mechanical combination lock (also referred to herein as “combination locks,” “locks,” and “mechanical locks”), however, is time-tested and finds broad use in applications where there may be exposure to moisture or where a backup power supply is not readily available. These applications include, for example, commercial and home safes, vaults, and automated cash machines.
Combination locks, by way of introduction and example, include a plurality (e.g. three or four) wheels, each wheel having a first surface, a second surface, and a peripheral edge. Each wheel's peripheral annular edge has at least one “notch” (also referred to as a “tumbler gate,” “wheel gate,” or “gate”) thereon. The “wheels” are also referred to as “tumbler wheels,” “tumblers,” “tumbler assemblies,” “wheel assemblies,” “tumbler wheel assemblies,” “tumbler rings,” or “gate wheels.” Together wheels are generally jointly referred as the “tumbler stack,” “tumbler pack,” “wheel stack,” or the “wheel pack.” In general, more wheels included in a combination lock make the lock more secure. A “spindle” (also referred to as a “drive shaft”) has a “combination dial” (also referred to as “dial” or “dial plate”) substantially at one end and a “drive cam” (that has at least one “drive cam gate,” “cam gate,” or “gate” on its peripheral annular edge) substantially at the other end. The wheels are positioned around a hub through which the drive shaft is positioned, the wheels being between the combination dial and the drive cam, with the wheel closest to the combination dial being referred to (by convention) as the #1 (or first) wheel, the wheel adjacent the #1 wheel being referred to (by convention) as the #2 (or second) wheel, the wheel adjacent the #2 wheel being referred to (by convention) as the #3 (or third) wheel, and, if present, the wheel adjacent the #3 wheel being referred to (by convention) as the #4 (or fourth) wheel. For purposes of description only, the first surface of each wheel is the surface facing the combination dial and the second surface of each wheel is the surface facing the drive cam. The drive cam has a “drive pin” (an engager such as a raised element, tab, or bump) on it that matches a “wheel fly” (an engager such as a raised element, tab, or bump suitable for interacting with an adjacent drive pin) on the second surface of the #3 wheel (the wheel adjacent to the drive cam, which could also be the #4 wheel if a fourth wheel is present). Each wheel, except the #1 wheel, has a drive pin on its first surface that matches an adjacent wheel fly on the second surface of an adjacent wheel (or the drive cam). The #1 wheel has a wheel fly on its second surface, but does not have a drive pin. When the combination dial is turned (also referred to as “rotated” or “spun”), it rotates the drive shaft and the attached drive cam. When the drive pin on the drive cam interacts with the wheel fly on the adjacent wheel (the #3 wheel in this example), that wheel begins rotating. When the #3 wheel's drive pin interacts with the wheel fly on the adjacent #2 wheel, that wheel begins rotating. When the #2 wheel's drive pin interacts with the wheel fly on the adjacent #1 wheel, that wheel begins rotating. In other words, the sequence repeats so that the adjacent drive pins and wheel flies interact (becoming properly aligned) until all the wheels are rotating together in response to the rotating of the combination dial. This process is called “picking up the wheels” because after several spins, all the drive pins and wheel flies will be matched up and all the wheels will be spinning. When a user stops rotating the dial and turns the dial the other way, the first wheel (the #1 wheel) is left in place. When direction of the rotation changes again, the second wheel (the #2 wheel) is left in place, and so on. When all the wheels have been left in the correct position, the tumbler gates will be aligned and the drive cam gate will be aligned after an additional rotation. Over the wheels rests a bar called the “fence.” The fence stops the lock from being opened by preventing the lever arm nose from engaging the drive cam gate. When the gates in all the wheels are aligned, the fence falls into the slot formed by the aligned gates, allowing the lock to be opened. In other words, the “combination” is reached when the gates in the wheels are aligned.
Combination locks are often described by how many wheels they have. In general, more wheels included in the lock make the lock more secure. In general, for each wheel there is one number in the combination. A combination lock with three wheels, for example, may be referred to as a “three wheel combination lock.” A three wheel combination lock would have three numbers in its combination. Three wheel and four wheel combination locks typically have up to 100 digits on the dial face and thus can provide 106 to 108 permutations for use as a combination.
Persons using combination locks will typically change the combination to a set of numbers known only to them, and in this process can inadvertently fail to set the combination precisely, firmly, and/or correctly, so that the desired combination does not work after the structure to which the lock is attached (e.g. a safe) is closed. Dirt, oils, other residues, or wear on the mechanism can also result in a slipped combination, resulting in what is known in the trade as a “lock out,” where an individual is unable to open his own lock or safe. Restoring access is expensive, disruptive, and requires the services of a professional safe technician (e.g. a locksmith). To avoid this, users are advised to test a new combination several times before closing the lock, but professional safe technicians have found steady work as a result of user haste and slipped or damaged tumblers. Thus there is a need for the ability to more reliably change a combination and yet be able to resist slippage, grit, or residues, and also centrifugal force. A good measure of slip resistance, albeit a destructive test, is a torque test applied to a tumbler wheel assembly. Industry standards perform at up to about 50 or 60 inch-pounds of torque at failure, the point at which the interlock between the gate rings and the combination tumbler ring is lost.
Also of interest in comparing combination locks is an endurance dialing test, where an automated dialer repeatedly rapid dials the combination until it wears out or fails for lack of service. A typical industry benchmark for a high-speed endurance dialing test is about 10,000 complete cycles to failure.
The interlock lever arms or pawls of industry standard combination locks are typically provided with teeth that have not changed much since early patents such as U.S. Pat. No. 901,116 to Murphy (the “Murphy reference”) and U.S. Pat. No. 1,484,692 to Weber (the “Weber reference”). The Murphy reference addresses the issue of the permanence of any adjustment to the combination and proposes a locking dog with inner edge toothed and concaved to conform to the curvature of the outer peripheral edge of the combination tumbler ring it opposes when urged into contact by a rotatable cam. As shown, the locking dog and combination tumbler ring are supplied with sawtooth-shaped teeth. Similarly, the Weber reference discloses a spring-operated lever and tooth surface of a combination wheel, which allows the user having a special change key (cam key) to change the combination when the safe is open. The Weber lever, when the wheel is spun rapidly, may be lifted away from the combination tumbler ring, scrambling the combination set by the user.
U.S. Pat. No. 3,981,167 to Phillips (the “Phillips reference”) again addresses the problem of changing the “combination” for the lock, and provides (see FIGS. 9-10 of the Phillips reference) a locking pawl with pawl teeth. Once the desired orientation between the drive wheel ring and the tumbler ring is accomplished, the pawl is engaged against the drive teeth for holding the two rings together during concurrent rotation. The teeth are generally saw-shaped.
U.S. Pat. No. 3,991,596 to Gartner (the “Gartner reference”) discloses using a locking lever with saw-shaped teeth to secure the tumbler. The art is characterized as follows: “The tumbler wheels 20 generally resemble the changeable tumbler wheels usually employed in combination locks, in that they comprise an inner hub 21 having a serrated outer periphery that is engaged by similar teeth on the jaw formation 22 of a resilient interlocking lever 23 of peripheral or rim portions 24 of the tumbler wheels each having a tumbler gate or peripheral recess 20a therein.”
U.S. Pat. No. 4,312,199 to Uyeda (the “Uyeda '199 reference”) adopts a similar approach, disclosing use of opposing teeth to position a drive member with respect to plastic gate ring (FIGS. 6-8 of the Uyeda '199 reference). The teeth are generally saw-shaped and are not believed to be durable and slip resistant. In U.S. Pat. No. 4,353,231 (the “Uyeda '231 reference”), Uyeda addresses the problem differently, using frictional effects between opposing undulating surfaces to prevent slippage.
U.S. Patent Application Publication No. 2004/0211233 to Jasper (the “Jasper reference”), discloses a key-operated combination change mechanism having four arcuate inner spring arms, each provided with saw-shaped teeth for meshing with teeth on the wheel rings (see paragraph 0062 of the Jasper reference).
Thus it appears that the art as a whole solves the problem of frictional interlocking contact between outer gate rings by interposing teeth having a saw-shaped, serrated, or undulating profile and/or beveled tooth faces. These teeth, by their nature, have surfaces that will tend to ride up on each other when subject to force, are inherently prone to slippage, and, as shown by experience, will generally fail when subjected to 50-60 inch-pounds or less of rotational torque. These tooth designs also are prone to “lock out” when subjected to deposits of grit or other residues that gradually lift the teeth apart.
Finally, it is also known that a combination lock can be defeated by an armed robber using intimidation (duress) to force an individual to dial the combination, or by a very skilled lock manipulator, who senses subtle changes in the smooth operation of the dial to divine all or part of the combination. Many combination locks can be opened by knowing only an approximate combination and by vibrating the dial to drop the fence into the gates.
These problems and other disadvantages of current designs are addressed by the present invention.
This invention is related to mechanical combination locks. In more specificity, the invention relates to resistant mechanical combination locks and improvements thereto and is generally referred to herein as the “locking system.” Preferred locking systems described herein include one or more of the following features:
The combination change/set feature, key stabilization feature, improved duress feature, and fence control feature may be used individually or combined.
A preferred method for forming an interlock lever arm of a combination lock, the interlock lever arm with micro-fingers includes the steps of: (a) designing a first micro-finger by drawing two concentric circles around a center, an inside circle with radius R and an outside circle with radius R′, wherein the radius R is the desired radius of a combination tumbler ring having a circumference, and the difference between R and R′ is the desired height of the micro-finger; (b) intersecting the concentric circles with least two radial projections separated by an arc corresponding to the width of the desired micro-finger, the radial projections defining flanking flats of the micro-finger; (c) drawing a convex curvature on the crown of the micro-finger, the crown facing the center and smoothly joining the flanking flats; (d) drawing a second micro-finger, wherein the first and second micro-fingers are joined at the root by a concave curvature mirroring the convex curvature of the crown; (e) continuing to draw micro-fingers around the full circumference, thereby forming a curve representing, in negative space between the micro-fingers, a full profile of a digitated combination tumbler ring circumference; (f) subtracting a clearance from the full profile and drawing outside the concentric circles but intersecting in an arc therewith, a lever shape of an interlock lever arm having an arcuate member with concave radius R′, the arcuate member having drawn thereon a row of the micro-fingers, wherein the micro-fingers of the lever arm are configured for interdigitatingly engaging the digitated combination tumbler ring circumference, the lever shape further having a fulcrum configured thereon; and (g) forming the interlock lever arm by punching the lever shape from sheet stock, the lever shape having a row of micro-fingers arcuately disposed thereon. The method may further include the step of forming the interlock lever arm to have an arcuate member with concave radius R of about or slightly greater than 1.25 centimeters, a micro-finger height of about 0.65 millimeters, and a micro-finger width of about 1 degree of arc.
A preferred combination lock with a combination dial operatively linked to a drive cam and a plurality of tumbler wheel assemblies rotatably stacked on a hub to form a tumbler stack within a lock case, each of the tumbler wheel assemblies having a tumbler gate, the drive cam having a drive cam gate for engaging a nose of a pivotable fence lever arm, the fence lever arm for retracting a slideable lock bolt when a correct combination is dialed, and an interlock mechanism in each of the plurality of tumbler wheel assemblies, the combination lock includes: (a) a combination tumbler ring having an inside radius for engaging the hub and a circumference digitated with micro-fingers, the circumference with radius R′ at the root of the micro-fingers and radius R at the crown of the micro-fingers; and (b) at least one interlock lever arm with a fulcrum for opposingly contacting the circumference of the combination tumbler ring, the interlock lever arm with first end having a plurality of micro-fingers disposed on an arcuate member with concave radius R, the micro-fingers of the interlock lever arm for interdigitatingly engaging the circumferential micro-fingers of the combination tumbler ring in a gripping action, wherein the circumferential fingers and the interlock lever arm micro-fingers are formed with opposable crowns and roots and opposable flat-on-flat flank faces for cooperatively resisting rotational torque applied thereto when interdigitatedly engaged.
In a preferred combination lock such as that described above (although not limited thereto), the fulcrum may be disposed between a first end and a second end of the interlock lever arm and, the interlock mechanism further includes a rotating lug cam for applying a force to the second end for leveraging the gripping action.
In a preferred combination lock such as that described above (although not limited thereto), the first end of the interlock lever arm further includes a spring arm member for biasing the arcuate member to disengage the gripping action when the rotating lug cam force is not applied.
In a preferred combination lock such as that described above (although not limited thereto), the interlock mechanism includes a pair of interlock lever arms, and the fulcrum of each of the interlock lever arms of the pair is configured for cooperatively exerting a gripping pincer action on the combination tumbler ring when actuated by the lug cam.
In a preferred combination lock such as that described above (although not limited thereto), the interlock mechanism of the tumbler wheel assemblies being configured for resisting greater than 100 inch-pounds of rotational torque on the spline when interdigitatedly engaged.
In a preferred combination lock such as that described above (although not limited thereto), the micro-fingers of the interlock lever arm and combination tumbler ring being dimensioned with a clearance of at least 0.001 inches.
In a preferred combination lock such as that described above (although not limited thereto), the lock case is provided with a lock case lid and the lock case lid is configured with a keyhole for receiving a winged change key, the keyhole having an internal boss for stabilizing alignment of the change key during use.
In the combination lock described above, any one of the plurality of tumbler wheel assemblies is configured as a duress tumbler wheel assembly for actuating an alarm, the duress tumbler wheel assembly being associated with a microswitch module associated with a rollerswitch for operatively contacting the duress tumbler wheel assembly.
In a preferred combination lock such as that described above (although not limited thereto), the microswitch module with rollerswitch is at least partially encompassed in a microswitch assembly, the microswitch module positionable within the microswitch assembly in a position corresponding to the position of the duress tumbler wheel assembly.
In a preferred combination lock such as that described above (although not limited thereto), the microswitch module with rollerswitch is at least partially encompassed in a microswitch assembly. The microswitch assembly further includes interchangeable spacer blocks configured so that the microswitch module can be changeably positioned in operative relation to a duress tumbler assembly at any level of the tumbler stack.
In a preferred combination lock such as that described above (although not limited thereto), the duress tumbler wheel assembly may further include: (a) a duress gate on a peripheral edge thereof; (b) a Y-shaped duress lever arm that include a first end including a first branch with a shoulder (cam shoulder) and a resilient spring tine second branch and a blocking arm second end; (c) a pivot pin generally at a midpoint between the first end and the second end; and (d) the cam shoulder having a concealed position and an exposed position, resilient spring tine second branch for urging the cam shoulder to the concealed position within the tumbler wheel assembly.
In a preferred combination lock such as that described above (although not limited thereto), an alternative duress tumbler wheel assembly may further include: (a) a duress gate on a peripheral edge thereof; (b) a duress lever arm; (c) a pivot pin generally at a midpoint between the first end and the second end; and (d) the cam shoulder having a concealed position and an exposed position, the spring tine for urging the cam shoulder to the concealed position within the tumbler wheel assembly. The duress lever arm may have a first end with a cam shoulder (a spring cavity defined in the first end), a blocking arm second end, and a spring positioned within the spring cavity.
In preferred combination locks such as those described above (although not limited thereto), the blocking arm second end is positioned to occlude the duress gate when the cam shoulder is in the concealed position, and rotatingly urges the cam shoulder to the exposed position when displaced from the duress gate by the action of the fence dropping into the duress gate, and further wherein the rotation can be reversed by the action of the spring tine without triggering an alarm.
In preferred combination locks such as those described above (although not limited thereto), the blocking arm second end is positioned to occlude the duress gate when the cam shoulder is in the concealed position, and rotatingly urges the cam shoulder to the exposed position when displaced from the duress gate by the action of the fence dropping into the duress gate.
In preferred combination locks such as those described above (although not limited thereto), the rollerswitch of the microswitch module is operatively engaged by the cam shoulder in the exposed position when the lock mechanism is rotated to retract the lock bolt, thereby triggering an alarm by closing an electrical circuit.
The preferred combination lock described above may further include: (a) an excentric trigger pin mounted on an outside face of the drive cam; and (b) a trigger plate pivotably mounted at a fulcrum on the lock case, the trigger plate having an overcenter arm, a stop arm, and a cam follower arm disposed around a common pivot point on the lock case (housing), wherein the overcenter arm is operatively coupled to the fence lever arm by a coil spring such that the nose is normally biased to a first position raised above the drive cam and drops down toward the drive cam gate in a second position for less than 35 degrees of rotational arc when resiliently urged by the excentric trigger pin acting on the cam follower arm.
In a preferred combination lock such as that described above (although not limited thereto), the trigger plate may further include: (a) a bracket for mounting the overcenter spring, wherein the bracket is vertically elevated above the overcenter arm and displaced counterclockwise from the rotational line of the overcenter arm by a distance of about 4 millimeters, the clockwise displacement reducing the stretch of the spring and sharpening the transitional arc from first position to second position; (b) a half-moon-shaped apron formed on the overcenter arm, the half-moon-shaped skirt extending under the coil spring and over the nose and the drive cam gate; (c) a plastic body, generally formed of nylon with glass fill, having translucency, resilience, and increased resistance to wear; and (d) a stop arm having a pendant stop dog for opposing the lock case.
In a preferred combination lock such as that described above (although not limited thereto), the trigger plate may further include at least one feature selected from the group consisting of: (a) a bracket for mounting the overcenter spring, wherein the bracket is vertically elevated above the overcenter arm and displaced counterclockwise from the rotational line of the overcenter arm by a distance of about 4 millimeters, the clockwise displacement reducing the stretch of the spring and sharpening the transitional arc from first position to second position; (b) a half-moon-shaped apron formed on the overcenter arm, the half-moon-shaped skirt extending under the coil spring and over the nose and the drive cam gate; and (c) a plastic body, generally formed of nylon with glass fill, having translucency, resilience, and increased resistance to wear.
The foregoing and other objectives, features, combinations, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.
The accompanying drawings illustrate various exemplary locking systems and features thereof and/or provide teachings by which the various locking systems and features thereof are more readily understood. These drawings are incorporated in and constitute a part of this specification.
The drawing figures are not necessarily to scale. Certain features or components herein may be shown in somewhat schematic form and some details of conventional elements may not be shown or described in the interest of clarity and conciseness. The drawing figures are hereby incorporated in and constitute a part of this specification.
This invention is related to mechanical combination locks. In more specificity, the invention relates to resistant mechanical combination locks and improvements thereto and is generally referred to herein as the “locking system.” Preferred locking systems described herein include one or more of the following features:
Before describing the locking system and the figures, some of the terminology is reviewed. Certain terms are used herein to refer to particular features, steps or components, and are used as terms of description and not of limitation. As one skilled in the art will appreciate, the same feature, step, or component may be referred to by different names. Components, steps, or features that differ in name but not in function or action are considered equivalent and not distinguishable, and may be substituted herein without departure from the invention. Certain meanings are defined here as intended by the inventors, i.e. they are intrinsic meanings. Other words and phrases used herein take their meaning as consistent with usage as would be apparent to one skilled in the relevant arts. The following definitions supplement those set forth in the Background and other sections of this specification.
In general, the inventive features set forth herein may be described as addressing one or more of a pair of problems. First, the preferred locking systems preferably address the problem of increasing the strength and reliability of the preferred locking systems. Second, the preferred locking systems preferably address the problem of crime prevention.
With regard to the first problem of increasing the strength and reliability of the preferred locking systems, the locking systems described herein have been tested using high-speed repetitive autodialing machines (i.e. cycling at more than 300 cycles per minute), which cycle the combination automatically, and have been found to endure more than 15,000 consecutive openings, in some cases as many as 75,000 openings, in contrast to other conventional locks that have been found to fatigue or fail at about 5,000 to 10,000 openings.
With regard to the second problem of crime prevention, preferred locking systems described herein are able to prevent crimes or provide relief from crimes. These crimes are usually committed by the “cracking” of a combination lock by skillful manipulation or by the inflicting of duress on those with knowledge of the combination.
Preferred locking systems described herein solve these problems and other problems simultaneously because the enabling features are both subtle and strong; “subtle” for operation without obvious signs that reveal the combination to a skilled touch or alert the perpetrator that an alarm has been sounded, and “strong” for resisting brute force and abuse over an extended lifetime. Preferred locking systems are resistant mechanical combination locks that have one or more improvements that, alone or in combination, solve known problems of conventional combination locks.
One preferred locking system described herein is a mechanical combination lock having an improved combination change/set feature for changing the combination. Another preferred locking system described herein has an improved duress assembly and function that permits the user to select any of up to four tumbler wheel assemblies for the location of a duress microswitch. Yet another preferred locking system described herein has an improved fence control feature, where a trigger plate with a cam follower arm and an overcenter spring is positioned to drop the fence precisely into the drive cam gate only when the correct combination has been dialed and the tumbler wheel assemblies are properly aligned. Finally, preferred locking systems described herein include more than one of these features and/or other features that may be used in combination or separately to improve the performance of mechanical combination locks.
Combination Change/Set Feature:
As shown in
A change key (122) (
In this model, the nose (112) of the fence lever arm (110) is urged by a torsion spring wrapped around the lever arm pivot pin (113) to follow the circumference of the drive cam (108), but is restrained from engaging the drive cam gate (109) by the fence (111), which rides the circumferences of the tumbler wheel assemblies until all the tumbler gates (120) are aligned so that the fence (111) can drop in the space created by the aligned tumbler gates (120) and the lock can be opened.
Visible in
As shown in
When the fingers of the locking lever arm and the fingers of the combination tumbler ring are fully interdigitated, the flats of adjacent tines are contactingly opposed and the crowns (135a) and roots (135b) are also contactingly opposed. This cooperative interdigitation with opposing flats generally perpendicular to the angular direction of torque was selected to increase torque resistance, and has proved experimentally to be superior to other commercial designs, even with face widths of less than a few millimeters and root to crown depth of the fingers of only a few millimeters or much less. In one realized embodiment, root to crown depth is 0.65 mm and torsional resistance meets or exceeds 150 inch-pounds. A thousandth of an inch may be shaved from the outer dimension of the fingers of the interlock lever arm to ensure the opposing crowns and roots readily interlock when the interlock lever arm pivots to engage the combination tumbler ring. Surprisingly, this configuration of cooperatively interdigitated fingers significantly multiplies torsional resistance and has demonstrated even more impressive improvements in endurance dialing tests, properties that would seem to belie the fragile nature of the individual fingers.
By using a commonly radiused crown (135a) (
The details of a method for forming an interlock arm with micro-fingers are generally the steps as follows:
a) designing a first micro-finger by drawing two concentric circles around a center, an inside circle with radius R and an outside circle with radius R′, wherein the radius R is the desired radius of a combination tumbler ring, and the difference between R and R′ is the desired height of the micro-finger;
b) intersecting the concentric circles with least two radial projections separated by an arc corresponding to the width of the desired micro-finger;
c) drawing a convex curvature on the crown of the micro-finger, the crown facing the center;
d) drawing a second micro-finger, wherein the first and second micro-fingers are joined at the root by a concave curvature mirroring the convex curvature of the crown;
e) continuing to draw micro-fingers around the full circumference; thereby forming a curve representing, in negative space between the micro-fingers, a full profile of a digitated combination tumbler ring circumference;
f) subtracting a clearance from the full profile and drawing outside the concentric circles but intersecting in an arc therewith, a lever shape of an interlock lever arm having an arcuate member with concave radius R′, the arcuate member having a row of micro-fingers configured for interdigitatingly engaging the digitated combination tumbler ring circumference, the lever shape having a fulcrum configured thereon; and
g) forming the interlock lever arm by a process of precision punching the lever shape from sheet stock, the lever shape having a row of micro-fingers arcuately disposed thereon.
The benefit in performance in resistance and durability achieved in this way is an advance in the art.
The combination tumbler ring may be made by casting or machining the micro-fingers of the combination tumbler ring formed in a punch. It should be noted that alternative construction methods and materials (known or yet to be discovered) may be used to construct the combination tumbler ring and the micro-fingers thereon.
This inventive micro-fingered structure is illustrated with respect to pivotable interlock lever arms but also may be integrated into interlock pawls or other conventional gripping members known in the art (and referenced herein by incorporation) for changeably setting a combination of a combination lock.
Key Stabilization Feature:
A problem associated with changeable combination locks is removal or jiggling of the change key in the back of the lock case while the gate rings and associated combination tumbler rings are not fully interlocked. If this occurs, it would be possible to have a combination tumbler ring that could slip in its connection with the gate ring, effectively changing the combination. If the change key is loose, inadvertent slippage can occur resulting in a mis-set combination. Preventing a slip during removal or use of the change key can prevent or reduce the chances of an inadvertent lock out.
As shown in
The internal boss (126) is used to stabilize the change key (122) position during rotation. Working with the internal boss (126) is a pivot recess (125′) in the base of the lock case (
The boss may also be provided with a mated recess on the outside face of the lid. A cover-plug may be inserted into the keyway when not in use.
Interchangeable Duress Feature:
The purpose of a duress feature is to actuate a generally silent alarm if a person is forced to open a safe. Using the duress feature, the person so encumbered is able to open the safe as demanded, but by dialing a special combination that differs from the standard combination (typically by adding ten to the first number in the combination), an alarm is triggered. In other words, the duress tumbler wheel permits the user to intentionally misdial the combination in a predetermined way and so that he can open the lock and sound an alarm. The alarm may be, for example, a silent alarm and/or a remotely monitored alarm. The only known “duress features” are not interchangeable and are limited to the tumbler wheel assembly in the #1 (bottom) position of a combination lock.
The improved duress feature allows customization of the position of the duress switch. Unlike the prior art in which the duress feature was only associated with the #1 position, the improved duress feature can be selected based on the wants and needs of the user. In most situations a user will select a locking system that will come preset with the duress feature in a random position and may never change it. Resellers and sophisticated users could, however, customize the position repeatedly. Theoretically, the improved duress feature could be set to function in the #2 position one week, in the #3 position the next week, and the #1 position the week after that. For users who wish to customize the position of the duress switch, there is no option currently available.
An improved duress feature preferably uses a modified tumbler wheel assembly (200, 250) (referred to as a “duress tumbler wheel assembly” and shown in
Comparing
Although shown in the figures as the first exemplary duress tumbler wheel assembly (200) interacting with the first exemplary duress switch (220) and the second exemplary duress tumbler wheel assembly (200) interacting with the second exemplary duress switch (270), it should be noted that the first exemplary duress tumbler wheel assembly (200) can interact with the second exemplary duress switch (270) and the second exemplary duress tumbler wheel assembly (200) can interact with the first exemplary duress switch (220).
Several components of the microswitch assembly (220, 270) and the duress lever (201) are made from very flexible material such as a nylon material with about 15% glass. These may be made simultaneously in the same process.
While the interchangeable duress feature may be used in combination with the interlock mechanism (including at least one tumbler interlocking lever (132, 133) with digitated micro-fingers (135) and at least one combination tumbler ring (131) with digitated micro-fingers (131′) on its peripheral edge) of the invention as shown in
Fence Control Feature:
Preferred locking systems include a fence control feature that provides crime prevention in that it helps stop the “cracking” of a combination lock by skillful manipulation because it provides for “subtle” operation of the combination lock without obvious signs that reveal the combination to a skilled touch. Control of the fence is important in defeating lock manipulation, where a skilled safecracker can determine the position of the gate(s) by sensing subtle perturbations in the motion of the dial as the lock is cycled.
Turning to
In this apparatus, an overcenter spring (330) is stretched from a pin (331) affixed in contraposition to fence (311) on the fence lever arm (310) to a specially modified bracket (334) at the tip of what is herein termed a “trigger plate” (333), so-named for its hair trigger action. Also shown is an excentric (having the normally central portion not in the true center) trigger pin (335) affixed to the drive cam.
The structure of the preferred fence control feature (fence control mechanism) is depicted in perspective view as a fully assembled lock in
The mechanical linkage is shown in more detail in
The coordinated action of the overcenter spring (330) and trigger plate arms are shown in
In
In
The drop-in point of the lever arm nose is at number 98 and the fence contacts the peripheral edge of the gate wheels from number 95 to about number 4. This and the spring constant of the overcenter spring (330) precisely controls/limits the lever drop motion to a very narrow contact window and reduces the lever pressure such that one is not able to feel and/or note any difference in the fence contact. This 95˜4 zone is the exact position in which the lever nose is pulled down during normal operation. The spring constant of the overcenter spring (330) depicted in
When the trigger arm is dimensioned as shown, and using an LE014A04M extension spring supplied by Lee Springs (Brooklyn, N.Y.), or an equivalent thereof, the transition from the first position to the second position is very sharp and the spring is compliant throughout the range of motion required. This music wire, zinc plated spring was chosen after extensive testing, and has a free length of 0.75 inches, 39 coils, a wire diameter of 0.014 inches, and a rate of 1.08 lbs/inch. Advantageously, the spring operates within an acceptable fatigue range, as evidenced by endurance autodial testing, where between 15,000 and 75,000 cycles were obtained without deterioration in performance or degradation of the cam follower arm (336). Surprisingly, a plastic part formed as described here was found to have superior wear resistance to a metal part!
Also shown in
While the plastic trigger plate is bendable, it is resilient and quickly returns to its native conformation. The plastic also contributes to the quietness of the fence action and has an advantage in translucency, permitting observation of the workings during servicing.
The fence lever arm (310) pivots on pivot pin (313) as previously described. Detailed views of the lever arm (310) and drive cam (308) are shown in
It is common in combination locks for the fence lever nose (112) to ride normally on the outer circumference of the drive cam. However, a skilled manipulator can feel the outline of the tumbler and drive cam gates and can deduce the combination. Therefore, considerable effort has been made to develop a “fence control mechanism” for dampening telltale interactions of the fence (111) and lever arm nose (112) with the tumbler wheel assembly gates and drive cam gate. Exemplary attempts to develop a “fence control mechanism” are described in U.S. Pat. No. 3,045,466 (the “Herlong reference”) and U.S. Pat. No. 4,756,176 to Uyeda (the “Uyeda '176 reference”). As depicted in FIGS. 3 and 4 of the Uyeda '176 reference, a fence lever control device includes a biasing means, as shown, for normally biasing the lever to an inactive first position, and once each revolution of the dial, biasing the lever to a second position for contacting the drive cam and tumbler wheel assemblies. According to Uyeda, the biasing means consists of a spring connected at one end to the fence lever arm (110) and an overcenter acting arm connected to a second end of the spring, where the overcenter mounting arm is provided with an actuator means, consisting of a cam follower arm and a trigger pin mounted on the cam wheel. Uyeda goes on to relate, “if the combination has not been correctly entered and the gate wheel assemblies are not aligned to receive the fence, the fence will be held up by engagement with the outer peripheries of the wheel assemblies as the cam wheel gate passes beneath the nose of the fence lever and the spring connected between the fence and the overcenter arm will shift the overcenter arm away from its second position back into its first position” (column 2, lines 41-49). A combination lock with brass overcenter arm is commercially available.
However, in following the teachings of Uyeda, the description was not found to result in a smoothly working model. Difficulties were also found when the overcenter arm was pinned between the lever arm nose and the drive cam! After almost a year of trials, a spring having a substantially shorter working distance than the Uyeda spring, and a weaker spring constant, when combined with a plastic trigger arm having an isolating skirt or apron was found to achieve a very sharp transition from a first position to a second position with whisper-like control of cam and wheel contact with the fence, spending less than 35 degrees of rotational arc in the second position.
In contrast, the commercially available brass mechanism, marketed by LaGard, was observed to approach the drive cam well before the drive cam gate's arrival and to return to the first position only after the drive cam gate had passed, thus working so that the fence remains in contact with the gate wheels for a significant fraction of a revolution.
It is to be understood that the inventions, examples, and embodiments described herein are not limited to particularly exemplified materials, methods, and/or structures. Further, all foreign and/or domestic publications, patents, and patent applications cited herein, whether supra or infra, are hereby incorporated by reference in their entirety.
The terms and expressions that have been employed in the foregoing specification are used as terms of description and not of limitation, and are not intended to exclude equivalents of the features shown and described. While the above is a complete description of selected embodiments of the present invention, it is possible to practice the invention using various alternatives, modifications, adaptations, variations, and/or combinations and their equivalents. It will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiment shown. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
The present application is a continuation-in-part of U.S. patent application Ser. No. 12/963,625, filed Dec. 8, 2010, now U.S. Pat. No. 8,443,639. The present application is a continuation of PCT Application Serial Number PCT/US11/27005, filed Mar. 3, 2011. PCT Application Serial Number PCT/US11/27005 is a continuation-in-part of U.S. patent application Ser. No. 12/963,625, now U.S. Pat. No. 8,443,639. The present application is based on and claims priority from these applications, the disclosures of which are hereby expressly incorporated herein by reference.
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| Number | Date | Country | |
|---|---|---|---|
| 20130247626 A1 | Sep 2013 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2011/027005 | Mar 2011 | US |
| Child | 12963625 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12963625 | Dec 2010 | US |
| Child | 13898379 | US |
