A LOCK

Abstract

A lock (100) comprising a plurality of buttons (111), each button (111) having an axis along which each of the buttons (111) may be axially pressed between an un-pressed position and a pressed position, a locking plate (120), an actuator (114) configured to drive the locking plate (120): a locking mechanism (122) having an unlocked and a plurality of locked states, the plurality of locked states corresponding to different selections of buttons (111) having been pressed into their pressed positions; and a latch (117); in which, when the locking mechanism (122) is in the unlocked state, the locking plate (120) can be driven by the actuator (114) from a locked position into an 10 unlocked position so as to disengage the latch (117) and unlocking the lock (100), but when the locking mechanism (122) is in one of the locked states, the locking mechanism (122) prevents the locking plate (120) being moved by the actuator (114): the lock (100) further comprising a decoupling mechanism (200) by means of which the actuator (114) can drive the locking plate (120), the decoupling mechanism (200) being arranged to decouple the actuator (114) from the locking plate (120), so as to reduce any feedback indicative of which of the unlocked states the locking mechanism (122) is in passing from the locking plate (120) to the actuator (114). In one example, the decoupling mechanism (200) comprises a driven member (201) driven for motion by the actuator (114), a first resilient member (202) connecting the driven member (201) with the locking plate (120) and a second resilient member (203) connecting the locking plate (120) to a fixed member fixed relative to a housing of the lock (100); and in which the first (202) and second (203) resilient members each have a spring constant, with the spring constant of the first resilient member (202) being greater than the spring constant of the second resilient member (203).

Claims

1. A lock comprising: a plurality of buttons, each button having an axis along which each of the buttons may be axially pressed between an un-pressed position and a pressed position, a locking plate, an actuator configured to drive the locking plate; a locking mechanism having an unlocked and a plurality of locked states, the plurality of locked states corresponding to different selections of buttons having been pressed into their pressed positions; and a latch; in which, when the locking mechanism is in the unlocked state, the locking plate can be driven by the actuator from a locked position into an unlocked position so as to disengage the latch and unlocking the lock, but when the locking mechanism is in one of the locked states, the locking mechanism prevents the locking plate being moved by the actuator; the lock further comprising a decoupling mechanism by means of which the actuator can drive the locking plate, the decoupling mechanism being arranged to decouple the actuator from the locking plate, so as to reduce any feedback indicative of which of the unlocked states the locking mechanism is in passing from the locking plate to the actuator; in which the decoupling mechanism comprises a driven member driven for motion by the actuator, a first resilient member connecting the driven member with the locking plate and a second resilient member connecting the locking plate to a fixed member fixed relative to a housing of the lock; and in which the first and second resilient members each have a spring constant, with the spring constant of the first resilient member being greater than the spring constant of the second resilient member.

2. The lock of claim 1, in which the actuator comprises a rotating member having an eccentric cam which drives the driven member.

3. The lock of claim 2, in which the locking plate comprises a blocking member which, in the locked position of the locking plate, limits rotation of the actuator to a limit, but in the unlocked position of the locking plate, allows the actuator to rotate past the limit.

4. The lock of claim 1, in which the locking mechanism comprises a sub-mechanism for each button, with the sub mechanism blocking movement of the locking plate unless the button has been pressed a pre-determined number of times.

5. The lock of claim 4, in which: each button has an axis along which the button can be axially pressed between an un-pressed position and a pressed position: the lock comprises a button biasing member associated with each of the plurality of buttons, configured to bias each button towards the un-pressed position: each sub-mechanism comprises a spool, each spool comprising a plurality of circumferential grooves, each circumferential groove having a notch extending over a portion of the circumferential groove, wherein each notch on a given spool is angularly displaced relative to each of the other notches on that spool, the circumferential grooves being parallel and separated spaced apart at a groove spacing from each other; each sub-mechanism comprises a plurality of legs, each leg in communication with one of the buttons, wherein each leg is arranged to contact one of the circumferential grooves of one of the spools: the locking plate has a plurality of apertures, each aperture arranged to receive one of the spools therethrough; pressing one of the buttons causes the leg in communication with the button to translate the corresponding spool by one groove spacing, with releasing the button causing the leg to engage an adjacent groove: each sub-mechanism is arranged such that the translation of each spool causes a differently rotationally oriented notch to be adjacent to the locking plate, with the locking plate only being able to move into an unlocked position, when driven by the actuator, thereby disengaging the latch and unlocking the lock, if all of the notches which are adjacent to the locking plate are in an unlocked rotational orientation.

6. A lockable enclosure designed to contain one or more articles, the lockable enclosure comprising the lock of claim 1, wherein the latch of the lock must be disengaged to gain access to the articles.

7. The lockable enclosure of claim 6, being a key safe, safe, or a lockable cabinet or lock box.

Description

[0039] There now follows, by way of example only, description of an embodiment of the invention, described with reference to the accompanying drawings, in which:

[0040] FIG. 1 shows a rear elevation of a lock in accordance with an embodiment of the invention;

[0041] FIG. 2 shows a side elevation of the lock of FIG. 1;

[0042] FIG. 3 shows a rear perspective view of the lock of FIG. 1;

[0043] FIG. 4 shows an exploded rear perspective view of the lock of FIG. 1;

[0044] FIG. 5 shows a rear elevation of the lock of FIG. 1, as an unsuccessful attempt to unlock the lock is taking place;

[0045] FIG. 6 shows a rear perspective view of the lock of FIG. 1 in the same position as FIG. 5;

[0046] FIG. 7 shows a rear elevation of the lock in FIG. 1, as the lock is successfully unlocked;

[0047] FIG. 8 shows a rear perspective view of the lock of FIG. 1 in the same position as FIG. 7;

[0048] FIG. 9 shows a partially cut away view of a keysafe using the lock of FIG. 1;

[0049] FIG. 10 shows an enlarged perspective view focusing on the toggle of the lock of FIG. 1; and

[0050] FIGS. 11 to 13 show cross sections through the lock of FIG. 1, showing the operation of the toggle in different states.

[0051] FIGS. 1 to 13 of the accompanying drawings show a lock in accordance with an embodiment of the invention. This lock largely functions as described in FIGS. 8a to 8c and 9 of our previous application published as WO2017/190891 (the teaching of which is incorporated herein) save as described below. Save for in FIG. 9, the lock housing 99 has been removed to show the interior of the lock mechanism. Here, the housing is of a key safe, but this lock could be used in any number of situations.

[0052] The lock 100 comprises an actuator 114 having a handle (or elongate member) 115. In this example, when the handle 115 is turned clockwise the actuator 114 disengages latch 117, thereby unlocking the lock 100. When latch 117 is disengaged it is retracted through an opening in a latch plate 118.

[0053] To disengage the latch 117 a user must axially press one or more of the buttons 111 a predetermined number of times and turn the handle 115 clockwise. Each of the buttons 111 can be pressed more than once. A biasing member 113 comprising a spring biases each button 111 towards the un-pressed position, therefore when the user removes the pressing force the button 111 returns to the un-pressed position.

[0054] A shaft of each of the buttons 111 is configured to be insertable through one of a plurality of holes 121 in a locking plate 120. In other embodiments, only one column of buttons 111 may be provided, or more than two columns of buttons 111 may be provided.

[0055] The lock 100 further comprises a plurality of spools 122, one for each button 111. Each spool 122 comprises a plurality of parallel circumferential grooves 123, spaced along an axis parallel to the travel of the buttons 111. Each circumferential groove 123 has a notch extending over a portion of the groove. The notches on a given spool 122 are angularly displaced relative to each of the other notches 124 on that spool.

[0056] The lock is also provided with indexing means, which converts each button 111 press into a translation of one groove spacing of the spool 122 associated with that button 111. A retention mechanism retains the position of the spools unless released by a user to cancel a code entry. A user can set the code required for the lock, assuming that the lock has been opened and the user has access to the back of the lock as shown in FIG. 1 of the accompanying drawings, by rotating a setting mechanism 128 for each of the spools, which rotates the spools in their resting position. A number (e.g. 0, 1, 2, 3, 4) marked around the mechanism 128 that the arrow on each mechanism 128 is pointing to determines the number of presses of the corresponding button which is needed to unlock the lock.

[0057] The basic principle of the lock is that the lock plate 120 is moved by the actuator 114. of the lock 100. If all of the notches in the grooves are aligned so that the lock plate can move to its furthest travel (because the buttons have all been pressed the correct number of times), then the actuator can continue to move the latch 117. If not, then one of the notches will not be aligned with the lock plate 120 and will stop its travel.

[0058] In order to stop any feedback being passed from the lock plate 120 through the actuator to a user of the lock as to which if any of the notches are correctly aligned, we now provide a decoupling mechanism 200. This comprising a driven member 201 which forms a cam follower for an eccentric cam 205 formed as part of the actuator 114. Rotation of the actuator 114 in the clockwise unlocking direction therefore forces the driven member 201 downwards as viewed in the Figures.

[0059] The driven member is coupled to the locking plate through a first spring 202, with the locking plate being coupled to a fixed plate 210 (fixed to the housing) by second spring 203. The first spring 202 is mounted between a protrusion 214 on the driven member 201 and a protrusion 216 on the locking plate 120. The second spring 203 is mounted between the protrusion 216 on the locking plate 120 and a protrusion 218 on the fixed plate 210. Both first 202 and second 203 springs are helical springs: the spring constant of the first spring 202 is greater than that of the second spring 203, so that the first spring 202 is stiffer than the second spring 203.

[0060] Thus, if the actuator 114 is rotated whilst any of the spools are incorrectly orientated (as shown in FIGS. 5 and 6 of the accompanying drawings), the driven member 201 will transmit force to the locking plate 120 through the first spring 202, with the second spring 203 compressing to allow for the initial travel of the locking plate 120. The locking plate will engage one of the unaligned notches, and will cease movement, but further movement of the actuator will cause continued compression of the first spring 202. It is only when a stop 211 on the actuator 114 hits against a protrusion 212 on the locking plate 120 that the travel of the actuator 114 is stopped.

[0061] As such, the first 202 and second 203 springs act to decouple the impact of the locking plate 120 on the notches from the actuator, so that a user will receive consistent feedbackthe stop 211 hitting the protrusion 212-regardless of what incorrect combination of button presses has been input.

[0062] In the case that the correct combination has been entered and the notches are correctly aligned to unlock the lock (as shown in FIGS. 7 and 8 of the accompanying drawings), rotation of the actuator 114 in the unlocking sense will drive the driven member 201 downwards. The driven member 201 will transmit force to the locking plate 120 through the stiffer first spring 202, whilst the weaker second spring 203 compresses. The travel of the locking plate will be to the maximum extent, which allows the locking plate 120 to move to a position where the protrusion 212 no longer prevents the stop 211 from rotating. As such, the actuator 114 can be fully rotated to release the latch.

[0063] The secure operation of the lock can be improved by using the toggle shown in more detail in FIGS. 10 to 13 of the accompanying drawings. The toggle 250 is shaped as two parallel flat plates, displaced relatively to one another both perpendicular to their flat surfaces and parallel thereto, with the two plates being joined by connecting arms. The toggle 250 is pivotally mounted on protrusion 216 about a generally horizontal axis parallel to the flat surfaces.

[0064] When the driven member 201 is driven by the cam 205, if the locking plate 120 faces an impediment such that the first spring 202 significantly compresses, the motion of the protrusion 216 will cause the toggle 250 to pivot from the starting position shown in FIG. 11 to a protruding position shown in FIG. 13. This will engage a notch 251 in the housing and prevent further movement of the locking plate; this will be consistent regardless of what incorrect combination has been entered.

[0065] If the locking plate 120 does not face an impediment, the toggle will remain in the FIG. 11 starting position as the locking plate 120 moves, and the toggle 250 will not engage the notch 251. As such, the locking plate 120 can move to allow the lock to unlock.