GB2070121A - Mechanical Permutation Lock - Google Patents

Abstract

A mechanical permutation lock is operated by a series of buttons 3, some or all of which must be depressed in the correct sequence. The right button pivots a lever which acts on lug 533 to move an element 53(a) of a two-part stop 53(a), 53(b). Each 53(a) operates a catch mechanism 54, 55 to free the adjacent 53(a), operated by the next button in sequence, from associated element 53(b). Depression of this next button then opens a gap through which tooth 66(a) of plate (62) may move. If a button is pressed out of sequence, then catch 54, 55 is not freed and part 53(b) moves with 53(a) to block plate 62. When the right buttons have been pressed, turning shaft 9 to move plate 62 is permitted and latch bolt 7 is withdrawn. Once the lock is opened, it is automatically reset. A change of combination of digitals can easily be manually effected without any tool. <IMAGE>

Description

SPECIFICATION Mechanical Digital Lock The present invention relates generally to a mechanical digital lock, and more particularly to a mechanical digital lock that is operable through a series of mechanical operations actuated by the depression of digital keys. The lock comprises a combination of essential mechanisms including a plurality of key means, digital selecting means, identifying means, locking means and automatic resetting means. The number of digital combinations is enormous, and the lock cannot be opened unless the predetermined digitals are sequentially depressed on the key board. Once the lock is opened, it can be automatically reset. A change of combination of digitals can easily be effected manualiy without using any tool. With its novel structure, it is highly reliable.

Most of traditional key-depression digital locks are of electronic/mechanical type, and have a complicated structure. Wiring is usually necessary after installation, and the costs of both manufacturing and installation are comparatively high. The lock will be dead during circuit trouble or power failure, and this is the main drawback.

Some types of key-depression digital locks have been disclosed recently, however they are rather complicated and have unusually high cost and comparatively low reliability. A change of digital combination can only be effected by a skilled worker with special tools. Besides, only four digits are usually adopted, hence the number of combinations is quite limited.

We have devised a lock which can overcome the aforesaid drawbacks that existed in conventional digital locks and which can provide a new mechanical digital lock with novel design and high reliability, comprising digital selecting means having a diai arm with changeable insertions which can be easily relocated to change the digital combination. Preferably, from six to ten digitals are adopted, so that the number of combinations becomes enormous. The correct digits cannot be detected through hearing or touch.

The new mechanical digital lock can have mechanical means for idnifYing digital sequence. Key depression of a wrong sequence will result in a deadlock condition, and until the lock is manually reset it cannot be opened.

The lock can also provide an automatic resetting means which would be effected automatically after the lock is opened. The lock can be reapplied without additional operation.

Furthermore, the lock can have a unique design of lock core and latch which is suitable both for use on doors of left and right swings, and it can be of simple construction, to enable easier manufacture and installation, especially suitable for use on any kind of door.

The invention will now be further illustrated with reference to the accompanying drawings, in which: Figure 1 is a partial cutaway perspective view of a preferred embodiment of the mechanical digital lock; Figure 2 is a partial cutaway front view of the same embodiment; Figure 3 is a partial cutaway side view of the same embodiment; Figure 4 is a back view of the key panel; Figure 5 is a perspective view of a digital selecting means; Figure 6 is an exploded perspective view of the digital selecting arms; Figure 7 is a perspective view of the digital identification means thereof; Figure 8 is a top view of the digital identification means; Figure 9 is a partial cutaway side view of the digital identification means; Figure 10 is a partial cutaway front view showing the relation between the core plate and the latch means;; Figure 11 is a partial cutaway side view showing the relation between the core plate and the latch means; Figure 1 2 is a partial cutaway perspective view showing the essential part of the resetting means; Figure 1 3 is a schematic view showing an installation of the lock; and Figures 14 (A) and (B) are side views showing operation of the lock.

Now referring to Figures 1 to 3, the mechanical digital lock shown comprises: an assembly of case 1, frame 2, key means 3, digital selecting means 4, identifying means 5, core plate 6, latch means 7, resetting means 8, knob 9, inside opening means 10, base plate 11 and face plate 12.

The case 1 is composed of an upper case 1 a and a lower case 1 b, and detachably mounted by screws on the side walls of the base plate 11. The case encloses the whole mechanical means M of the lock. The upper case is detachably mounted upon the upper end of the lower case 1 b with screws.

The frame 2 comprises a pair of side walls 21-21 and two connecting plates 22 to hold tight a key panel box 31 with screws. Mechanical means M is mounted within the frame 2.

The key means 3 is mounted at the upper most section of the frame 2 on the connecting piate 2? thereof. The key means 3 comprises a key panel box 31, a plurality of keys 34, say ten in the present embodiment, representing usually numerals 0-9 and/or characters as required. The keys 34 are retained in key holes 33 provided in the key panel box 31 and each is biased by a spring 32 from behind. Key rod 35 extends from the back of each key 34 into the case 1. For the compactness of the layout, the ten keys may be arranged into two rows, five in the upper row and five in the lower row. Since it is desirable to arrange the end of key rods 35 into a single row to facilitate operation without interference, the ends 36 of rods 35 are bent as shown in Figure 4.

Digital selecting means 4 is disposed at a somewhat lower position than key means 3, and it comprises a number of sets of selecting arms 41 arranged parallel from front to rear; the number of sets of arms chosen in this embodiment is six, corresponding to the predetermined number of digits. Hence each of the six inserts 42 is provided to be detachably and selectively inserted on one of the upper ends of the sets of arms 41.

Each set of selecting arms 41, such as shown in Figure 5, comprises a number of arms corresponding to the number of the keys, in this case, ten. Each member of arm set 41 comprises an upwardly extended upper arm 41 a and each set has a lower arm 41 b extending from the lower end of the ten arms 41 in the set. Since each lower arm having forwardly bent tip 411 extends from a different set of arms, to avoid their overlapping, each of the six sets of arms is consolidated to provide axle plates 41 c at their ends in bearing socket 43 to be pivotally mounted on the side wall 21 of the frame 2, so that each set of arms can swing freely about the axle. For compactness of layout, the axles 41 c may be disposed at two different levels.In the meantime, to facilitate the lower tips 411 of downwardly extended lower arm 41 b reaching the identifying means, which is prearranged in a single row, the upper/lower arms 41 a/41 b of the arm 41, except the one furthest left (the first one), may be bent to a different extent of step with various length of horizontal part, so that the tips 411 can fall within one plane, where the identifying means is located.

Referring also to Figure 6, it can be seen that each upper arm 41 a of the ten arms in the set preferably has one or two positioning holes 412 to facilitate the insertion of inserts 42. The position is set by projecting nipples 421 provided inside the socket 42a of the inserts 42 to lock into the respective positioning holes 412. Each set of the six sets of selecting arms 41 is provided with one of such inserts 42. Upper arm 42b of the insert 42 extends forwardly and receives the touching of the end 36 of the rods 35 of the depressed keys. A gap is therefore reserved between the rod end 36 and the upper arm 42b of the insert 42.Since it is desirable that the upper arm 42b is in alignment with the single row rod ends 36, it is necessary to bend the upper arms 42b, except the one closest to the key, into stepped shape, and the extent of bend varies increasing the length of the horizontal portion from left to right. It is also necessary that the inserts 42 are so placed from the set closest to the key to the furthest set, according to the predetermined order of digital numbers.

The identifying means 5 is located under the selecting means 4, such as shown in Figures 7 to 9. It comprises a front fixing plate 51 a, a rear fixing plate 51 b, a guide plate 52 fixed between the two plates 51 a, Sib. A plurality of sets (corresponding to the number of selecting arm sets 41, i.e. six) of front sliding blocks 53a and rear sliding blocks 53b are slidably mounted in pairs on the guide plate 52. A claw 54 is pivotally disposed on each plate 52 and between adjacent pairs of blocks 53a-53b, a stopper 55 is disposed on each front sliding block 53a, except on the first or furthest left block 53a. A return spring 56 is provided between each front sliding block 53a and front fixing plate, and a compression spring 57 is disposed between each front and rear sliding block, 53a, 53b.

The front fixing plate 51a and the rear fixing plate 51 b preferably both have a substantially "U" shaped cross section; however, plate 51 a is bigger than plate 51b and the guide plate 52 is clamped between them and fixed by screws.

Guide grooves 521 corresponding to the number of selecting arm sets 41 are disposed at even spacing on the guide plate 52. The front and rear sliding blocks 53a, 53b are slidably mounted in pairs on the plate 52 with their sliding channel formed on individual legs 53a' and 53b' inserted into the guiding groove 521. A recess 531 is formed in the front wall of the front sliding block 53a, a spring 56 with one of its ends retained in the recess 531 and the other end pushes against the front fixing plate 51 a. Upon each front sliding block 53a is a wedge like projection 532 facing a straight rear wall 533. At the back of this rear wall is provided a spring retaining stud 534, on the front side of the wall 533, a hook like projection 535 is disposed. Between projections 532 and 535, a stopper 55 is mounted with a pivot 551.

Biased by the force of spring 58, the front end 552 of the stopper 55 tends to rotate to tiie left, yet the rear end 553 of the stopper 52 falls against the side surface of the projection 535 to ensure limited projection of the front end 552. An inclined surface 536 is formed in front of the leg 53a' of the front sliding block 53a, and a locking recess 537 is drilled at the bottom of the incline.

The rear sliding block 53b has a rear wall 501, and a spring retaining stud 502 is disposed on the inner side facing the stud 534 on front sliding block 53a. A compression spring 57 is retained between these two studs. An arm 503 extends forward from the side of the rear sliding block 53b and a triangular shaped stopper 5U4 is formed at the tip of the arm 503 to be almost in contact with the projected end 552 of the stopper 55. The arm 503 is attached to block 53b, such that if stopper 504 is forced to move, by end 552 for example, then block 53b will be caused to move.

A hook shaped claw 54 is pivoted through a pin 541 to the guide plate 2, at a position between adjacent grooves 521, and is biased by a spring 542 so that the incline 544 of the claw end 543 is forced constantly against the incline on projection 535. The front end 543 of the claw 54 keeps an appropriate gap with the front end 552 of the stopper 55.

Lock core plate 6 having a side cross-section of "L" is disposed under the identifying means 5, as shown in Figures 10, 11. The core plate 6 comprises a front plate 61, a back plate 62 and a bottom plate 63 on the front plate 61, and one each long and short claw 64, 65 are formed therefrom.A teeth portion 66 having a plurality of teeth is formed on the back plate 62, in a position under the blocks 53a, 53h, with the projected teeth just engaging into a continuous groove 59 formed between the legs 53a', 53b' of the blocks 53a, 53b. A rectangular aperture 68 with a vertical flap 67 punched out along one side is disposed at the centre of the front plate 61 of the core plate 6, and one pair of arms 621, 631 extend from sides of the back plate 62 and the bottom plate 63, respectively, to be slidably inserted into pairs of guides 23 provided on side walls 21 of the frame 2 for the supporting of core plate 6. A returning spring 69 is provided on the left arm 621 to bias the core plate against the right side wall 21.A revolving arm 60 is pivoted to a pin 601 on the inner centre of the base plate 11, with its upper and lower end engaged respectively to the latch 7 and to the short claw 65, to provide for the door opening.

Latch means 7 is provided laterally across the central part of the frame 2 and located between the selecting means 4 and the identifying means 5. Latch 7, with its one end formed into a wedge head 71 and the other base end 73 having a central recess 72, is slidably mounted into a pair of horizontal guides 24, formed on the two side walls 21 of the frame 2. The base end 73 of the latch 7 is slipped into a closed end nylon socket 25 inserted in one of the horizontal guides 24. A spring 74 is retained between the socket 25 and the central recess 72 to bias the latch to cause its wedged head to project out of the side wall 21. A follower member 75 having a left plate 75a and a right plate 75b is detachably clamped to the middle of the latch 7.The bent end of the long claw 64 extends at the right side of the left follower plate 75a as drawn, so that when the core plate 6 moves to the left, claw 64 will pull the follower member 75 to the left against the spring 74, to cause retreat of the wedge head 71 into the frame 2, allowing the door to be opened.

The resetting means is located under the identifying means 5 and in parallel with the core plate 6, as shown in Figure 12. It comprises a supporting rack 81 preferably having a substantially "S" shaped cross-section. The rack 81 with its two ends passing through two vertical posts 82 is movable up and down freely. The lower end of each post 82 is fixed at the lower part of the frame 2, while the upper end passes through the bottom of the guide plate 52 and is limited by a snap ring 83. A spring 84 is provided at the lower end of the post in a position between the supporting rack 81 and the frame 2, to bias the rack upward. A spacing sleeve is disposed on the post 82 between the guide plate 52 and the rack 81, to keep a constant distance therebetween.On the rack 81, a plurality of locking pins 86 corresponding to the position of the front sliding block 53a are disposed to have their upper ends passing through the guide plate 52 and projected thereabove under the front incline 536 of the block 53a, while their lower ends are allowed to stick out under the lower deck 81 L of the rack 81 to a certain extent. A snap ring 87 is provided at the middle section of the locking pin 86 and just under the upper deck 81 U of the rack 81. Between the snapring 87 and the middle deck 81 M of the rack 81, a spring 88 is provided to bias the pin 86 upwards. When the front sliding block 53a moves forward, the pin 86 will fall within the recess 537 and lock the block in position.

A knob 9 is provided at the centre front of the frarne 2, with a knob handle 90 disposed out of the face plate 12, and socket sleeve 91 extending inwardly through the face plate 12 and base plate 11 to reach the coreplate 6. A flange 92 is formed at the inner end from the centre of the flange, and a reset actuating plate 93 is further extended through the aperture 68 to reach the lower deck 81 L of the supporting rack 8. A core actuating plate 94 is bent from the upper edge of the flange 92 to engage with the vertical flap 67. When the knob 9 is turned counterclockwise, the core actuating plate 94 engages the flap 67 to force the core plate to the left to open the lock. When the knob is turned clockwise, the reset actuating plate 93 forces the rack 8 to move downwardly to accomplish manual reset.

An inside opening means 10 is provided at the centre of the lower case 1 b. It has a turning knob 101 having a shaft 102 retained by a bearing 103 fixed to the lower case 1 b and passed into the frame 2. A cam 104 is provided at the end of the shaft 102 to engage with the right plate 75b of the follower member 75. When the knob 101 is turned, the cam 104 actuates the follower 75 to allow the door to be opened directly from inside without the aid of the core plate 6. The base plate 11, as shown, serves to connect the face plate 1 2 from outside as well as the whole frame 2, and for fastening onto the inner wall of the door. The face plate 1 2 is a metal cover to be connected with the knob 90. A rectangularopening 121 is provided to facilitate display of the key panel 34 of the key panel box 3.Three hollow posts 122 stick out to facilitate bolts extending from the base plate 11 to pass through and fasten thereon. The variation in door thickness can be accommodated through the adjustment of the thread length of these bolts.

The above illustrates a construction of a digital lock, the following describes its function.

Figure 13 shows one way of installing a lock.

According to the templale furnished by the manufacturer, a rectangular opening h1, a round opening h2 and three bolt holes h3 are made in the door. A face plate 12 is installed from outside of the door with three threaded posts 122 which pass through the door of thickness D. Then the base plate 11 is installed from inside, the socket sleeve 91 is aligned with the knob 90, and are force fitted. A little turning may be helpful to enable the groove provided on the sleeve 91 to be matched exactly with a projection provided inside the knob base. The three bolts are passed from inside the base plate 11, through the corresponding bolt holes formed on the base plate 11, they are fastened into three threaded posts 122 of the face plate 12, so that the base plate 11 is fitted tightly against the face plate 12 with the door thickness inbetween.The fixing of the base plate 11 on the door D is further reinforced by four wood screws. The pre-assembled frame including key panel box, selecting means, identifying means, resetting means, latch means, core plate etc. may be inserted from above so that the latch enters into the side wall opening on the base plate 11. The whole frame can be forced in with ones hands, and door knob 9 may be turned a little to enable the flap 67 on the core plate 6 to be close to the core plate actuating plate 94 on the socket sleeve 91 of the knob 9. Both sides of the frame 2 are hence enclosed in the side walls of the base plate 11. Three screws are fastened on each, so that the frame 2 and the base plate 11 are tightly connected. The case 1 is positioned and fastened with screws to the side walls of the base plate 11.By then the installation of the lock is finished; exposed outside the door are the knob 9 and key panel 31,the wedge head 71 of the latch protrudes from the side of door D into a latch pit (not shown) provided on the door sash.

When the combination numbers are depressed incorrectly and knob 9 turned left, teeth 66 are hampered by the legs 53a'; the core plate actuating plate 94 is in contact with the flap 67 and tending to force the core plate to the left, but the core plate is locked and the latch 7 cannot be moved and the door D cannot be opened.

Now referring to Figure 14 (A) and (B), if the keys 34 are depressed in a predetermined sequence, the key rods 35 in turn push the corresponding inserts 42 of the selecting arm set 41, then the lower arm tip 41 b swings about the axle centre 41 c and presses the rear wall 533 of each front sliding blocks 53a, forcing the blocks 53a to slide forward along the guide groove 521.

Since the first or furthest left of blocks 53a is not provided with a stopper 55, this particular block 53a is free to move independently forward without engaging its rear sliding block 53b. A gap "g" is then created between legs 53a'-53b' of blocks 53a, 53b to let pass the teeth 66 of the core plate 6. When the first front sliding block 53a reaches a position such that a corresponding locking recess 537 is aligned with the locking pin 86, the pin 86 if forced by the spring 88 into the recess 537, thereby anchoring the block 53a, so that when the key is released from depression, the block 53a stays and is not returned by the spring 56. The gap g is thus maintained for the passage of teeth 66 of the core plate 6.

When the first front sliding block 53a moves forward, the incline of projection 535 forces the claw 54 to move about the pivot 541 towards the second front sliding block 53a, towards the right as drawn. The front end 543 of the claw 54 pushes the stopper 55 on the second front block 53a toward the right as drawn, until the end 543 falls against the side wall of the second front block 53a and forces the front end 552 of the stopper 55 to retreat. By then the front end 552 of the stopper 55 is released from the stopper 504 of the arm 503 which extends from the rear sliding block 53b. Therefore, when the second digit of the combination is depressed on the key panel 34, the corresponding selecting arm set 41 repeats the function as before.The lower arm 41 b pushes forward the second front block 53a to move ahead independently and leaves a gap "g" between legs 53a'-53b' of the second set blocks 53a, 53b and releases teeth 66 of the core plate 6. This process repeats until all the six (or more) predetermined digits are depressed on the key panel. The six gaps "g" thus formed allow free passage of the teeth 66 of the core plate 6, so that when knob 9 is turned left to open the lock, latch 7 is forced toward the left by the actuating plate 94 through flap 67 (see Figure 10), and the long claw 64 on the core plate 6 in turn pushes latch 7 toward left against the spring 74, and wedge head 71 of the latch 7 thus retreats into the case 1, allowing the lock to be opened.

The identifying means 5 serves automatically to lock up when a key is depressed in error or in a wrong sequence. More particularly, the multi-sets of front/rear sliding blocks have to be operated in the correct sequence. A wrong depression or depressions following a wrong digital sequence will cause a front sliding block other than the first to be moved forward along the guide groove 521.

Since the preceding or the first digital number was not depressed in the first place, the first front block has not been moved forward, the first claw 54 was not rotated and the second front block or the front block of the wrongly depressed digit number is prevented from moving by stopper 55 bearing against stopper 504 of arm 503 extended from the rear block 53b. The forward movement of the second front block 53a would move the rear block 53b at the same time. No gap "g" will be created between legs 53a'-53b' of blocks 53a, 53b. Even if attempt is made later on to depress a series of digits in the right sequence, the fault will have already blocked the expected gap "g" and continuation of gap "g" is broken so passage of core plate 6 is prevented. The blocking of gap "g" occurs as many times as a key is wrongly depressed.

When the lock is opened, all the blocks 53a remain unreleased by the pins 86. After turning the knob 9 in a counter-clockwise direction, the resetting actuating plate 93 presses down the rack 81 of resetting means 8, pins 86 in turn release the front sliding blocks 53a to allow movement backward. At this stage, a part of the teeth 66 are retained between the front blocks and rear blocks, the front blocks have already been released by the pins 86, but have not resumed their original positions. When the knob 9 is turned to its dead end, the latch 7 retreats fully into the case 1, and the door may be opened. By releasing the knob 9, the core plate 6, biased by the spring 69, is restored to its original position, pins 86 stick out as in the original condition, and the front blocks biased by the spring 56 resume also their original positions. The resetting of the lock is thus accompiished. The latch 7 again projects out of the case, and automatically locks the door. In case anyone else has attempted to unlock the device, a clockwise turning of the knob before starting depression of the keys due to the downward action of the resetting actuating plate 93, lowers the rack 81 to force down the pins 86, and achieve resetting.

If it is desired to open the lock from within, one can turn the knob 101 clockwise, the cam 104 in turn moves the follower 75 of the latch 7 without affecting the core plate 6 and the identifying means 5, to retract the latch 7 directly to allow opening of the door. By releasing the knob 101, the latch 7 biased by the spring 74 resumes its position, and the knob 101 is restored also through the action of follower 75 and cam 104.

The above refers to a door with a lock mounted on the right side, as viewed from outside. The lock of the present invention is also capable of being installed to the left side of the door. The alteration can be easily effected by reversing the latch 7 and placing nylon socket 25 at the other end of the lock. In other words, the wedge head of the latch is placed to the left, the base end 73 is placed to the right, and the socket 25 is covered at the base end 73. The follower member is relocated reversely which can be done readily by the manufacturer or otherwise.

The lock opening operation then works as follows: the knob is still to be turned counterclockwise, and the core plate moves to left accordingly. Since the follower member 75A is reversely relocated, the plate on the follower member 75A is no longer moved by the long claw 64, only the upper end of the revolving arm 60 engages with the right side of the plate 75b, hence the short claw 65 forces the lower end of arm 60 to move left, and arm 60 rotates about the centre 601 to cause its upper end to move right and to push latch 7 toward the right through plate 75b. The latch 7 retreats to allow the lock to be opened. The revolving arm 60 was inactive in the right-mounted lock, since it did not engage with either of the plates 75a, 75b.

Combination change can be effected manually by changing the positions of inserts 42, as follows: open upper case 1 a, take down all the old inserts, then relocate according to a new desired digital number. The inserts are to be placed on one of the upper arms 41 a of each set of ten, the location of the inserts in the sets corresponds to the number sequence to be depressed on the key panel. Upper end 41 a of the arm sets 41 can be marked with numbers from 0--9, for the convenience of recognition.

Cracking of the lock by touch may be attempted by a potential burglar to find out which numbers are active, and false inserts 42 may be mounted to each blank upper end 41 a of the inactive numbers so that every push of keys 34 would produce the same feeling, since behind rod 35 of every key there would be an insert 42.

However, even without the false inserts, a combination of six out of ten of ten keys is complicated enough for any burglar to attempt.

The lock described gives an enormous number of combinations, and safety is reassured through the provision of selecting, identifying means as well as by the automatic resetting means.

Construction is simpler than other types, is less trouble and is easier to manufacture. Also, the combination can be easily changed without special tools. Since no conventional key has to be used, there is no problem of loosing one.

Claims (24)

Claims

1. A mechanical digital lock having digital keys, correct sequential operation of which allows a locking means to be retracted; operation of a key in its correct turn causes movement of a first locking member from a position which prevents retraction of the locking means to a position which allows retraction, and operation of that key out of sequence additionally causes movement of a second locking member in tandem with the first locking member which second locking member prevents retraction; the coupling between the first and second locking members, which allows movement in tandem, being broken by a correct preceding key operation.

2. Mechanical Digital Lock comprising: a case serving for cover-up of the entire lock mechanism; a frame for mounting the mechanical means of the lock; a base plate serving for installing the lock onto a door; a face plate installable outside the door to receive a key panel box; an assembly of mechanical means mounted within the frame including a key means, a digital selecting means, an identifying means, a lock core plate, a latch means, and a resetting means; and a knob means; and characterized by: By key depression operation, the selecting means and identifying mean being actuated; and the lock being opened by turning of the knob to actuate the lock core plate, in turn the latch means; in the meantime after lock being opened, the resetting means being also actuated to prepare the lock to be again locked.

3. Mechanical Digital Lock according to claim 2, wherein the key means is mounted on top within the frame and held tight by connecting plates; a plurality of keys are arranged in single or multiple row and displayed on the face of the key panel of the key panel box; and a plurality of key rods are extended from the back of each key into the frame.

4. Mechanical Digital Lock according to claim 3, wherein the ends of the key rods are displayed in one single row and fall in a same plane.

5. Mechanical Digital Lock according to claim 2, wherein said selecting means is mounted in the frame and below the key means, and comprises: a plurality of selecting arm sets in the number corresponding to the number of digits in the sequence that releases the lock, said sets are arranged parallel from front to rear, and a plurality of inserts to be freely inserted on the upper end of an arm on each set.

6. Mechanical Digital Lock according to claim 5, wherein each arm set comprises a series of arms in a number corresponding to the number of keys, and extending downwardly from the lower end of one of the arms in the row a bent lower arm, at both sides of the arm set, one each axle plates is provided.

7. Mechanical Digital Lock according to claim 5, wherein the lower arm of selecting arm sets extend each from different position in the row, so that they do not overlap and are arranged in a row within one plane.

8. Mechanical Digital Lock according to claim 4 wherein the position of each insert corresponding to the predetermined number of the key, said inserts each having a horizontally extended arm, the free ends of which fall on a row within one plane.

9. Mechanical Digital Lock according to claim 2, wherein the identifying means is located under the selecting means and comprises: a guide plate clamped between a front fixing plate and a rear fixing plate, with a plurality of guide grooves in a corresponding number of the selecting arm sets, disposed on the guide plate; a plurality sets of sliding blocks including one each front sliding block and rear sliding block slidably inserted in each of said guide groove; a plurality of claws each pivoted between adjacent pairs of grooves; one each stopper pivoted on each front sliding block; one each returning spring disposed between each front sliding block and the fixing plate; and one each spring disposed between the front and rear sliding blocks.

10. Mechanical Digital Lock according to claim 9, wherein the front sliding block having raised front and rear wall, a recess is provided in the front wall for the retaining of a spring, at the back of rear wall, a spring retaining stud is provided, while on the front side of the rear wall, a hook like projection is disposed.

11. Mechanical Digital Lock according to claim 9, wherein between the front and rear wall of the front sliding block said stopper is disposed and biased by a spring to cause its rear end to be against the side surface of the hook like projection, while its front end projects forward to be out of the side of said block.

1 2. Mechanical Digital Lock according to claim 9, wherein the front bottom of the front sliding block is inclined, and a vertical locking recess is drilled thereunder.

13. Mechanical Digital Lock according to claim 9, wherein the rear sliding block having a raised rear wall, a spring retaining stud is disposed on the inner side to be in opposite with the stud on front sliding block, a compression spring is retained between said studs, an arm is extended forward from the side of the rear sliding block, a triangular shaped stopper is formed at the tip of the arm to be in opposite against the stopper disposed on the front sliding block.

1 4. Mechanical Digital Lock according to claim 9, wherein the claw is of hook shape and is pivoted on the guide plate between adjacent pair of guide grooves and biased by a spring to force its claw end to have its back inclination pressed constantly against the inclination on the rear projection of the front sliding block, while the front end keeps an appropriate gap with the front end of said stopper disposed on the front sliding block.

1 5. Mechanical Digital Lock according to claim 9, characterized in that, when said selecting arm pushes said front sliding block to move forward along the guide groove, said stopper on the front sliding block is to engage with the stopper disposed at the tip of extending arm of the rear sliding block, to cause the rear block to move together with the front block; in the meantime, the rear projection of the front block through its inclination, forces the claw to pivotally turned toward next set of blocks, and causes the stopper on the front block of the next set to retreat, thereby let the stopper be released from the stopper, at the tip of extend arm of the rear block of the next set, so that when corresponding number is depressed on key panel and the selecting arm pushes forward the front block of the preceding set, to be able to slide independently and cause a gap to be created between the front and rear blocks.

1 6. Mechanical Digital Lock according to claim 9, wherein a locking pin is biased upwardly into the locking recess to assume the position when the front sliding block is pushed forward to have said locking recess positioned on top of the said locking pin.

1 7. Mechanical Digital Lock according to claim 2, wherein the locking core plate is located under the identifying means, and slidably at a horizontal position by means of two pairs of arms extended from both sides of the plate supported at the two side walls of the frame, one each long and short claw being formed on the front plate, while a plate with upwardly projected teeth is disposed at the rear, the teeth are positioned right under the said set of blocks and to be extended into the continuous gap formed between legs of the front and rear sliding blocks.

1 8. Mechanical Digital Lock according to claim 17, wherein a rectangular aperture is disposed at the front plate of the core plate, and a vertical flap is punched out along the left side of the aperture.

1 9. Mechanical Digital Lock according to claim 3, wherein the latch is disposed horizontally on top of the core plate and in a position between the selecting and identifying means and being slidable freely toward left and right, a wedge headed end of the latch sticks out of case of the lock while the base end is slipped into a close end socket which is inserted in one of the two horizontal guides on the frame, a spring is retained between the socket and a central recess formed in the base end of the latch, a follower member is detachably clamped to the middle of the latch and aligned with the long claw of the core plate to be moved thereby, to achieve the purpose of opening or closing of the latch.

20. Mechanical Digital Lock according to claim 2, wherein the resetting means is disposed in parallel with the locking core plate under the identifying means, and comprising: a "S" shaped supporting rack supported at two sides by a pair of guide posts planted on the frame and slidably up-down there upon; a pair of springs disposed around the lower end of the posts with two ends push against the rack and the frame; a pair of spacing sleeves enclosing each top end of the posts to assume a constant distance between the guide plate of the identifying means and the rack; and a plurality of locking pins corresponding to the number of the front sliding block, each biased upwardly by means of a spring.

21. Mechanical Digital Lock according to claim 20, the locking pins of the resetting means are to be aligned with corresponding pin recess under each front sliding block, when the front block moves to a position having the recess right on top of the pin, the front block is locked in position.

22. Mechanical Digital Lock according to claim 2, wherein the knob means having a socket sleeve extending inwardly through the face plate, the base plate to reach the core plate, a flange is formed at the inner end, from the center of the flange, a reset actuating plates is further extended through the aperture of the core plate to reach under the supporting rack of the resetting means, a core actuating plate is bent from upper edge of the flange to engage with the vertical flap at the side of said aperture.

23. Mechanical Digital Lock according to claim 2, wherein an inside opening means comprising a turn knob rotatably mounted to the back center of the case, a cam is provided at the end of the knob shaft the actuates the follower member on the latch, to enable the locked door to be opened from within.

24. Mechanical Digital Lock according to claim 1, substantially as herein described with reference to any one of the accompanying drawings.