GB1578559A - Construction for a cylinder lock and key - Google Patents

Description

(54) IMPROVED CONSTRUCTION FOR A CYLINDER LOCK AND KEY (71) I, CHUNG CHENG KU, a citizen of Taiwan residing at 63, Cheng Chou Road, Taipei, Taiwan, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to particularly described in and by the following statement: This invention relates to a cylinder lock and key.

Cylinder locks are generally comprised of a stationary housing and a rotatably mounted plug or cylinder and a plurality of pin tumblers of various lengths comprising an upper and lower segment which are pressed down from cavities provided in the housing by springs to engage with holes in the cylinder, thus preventing the latter from rotating. Upon insertion of a properly cut key each pin tumbler is raised so that the top of the lower segment is flush with the top of the cylinder, allowing the segments to separate and the cylinder to be turned in the housing.

However, to date all such cylinder locks employ pin tumblers which are laterally spaced along a single line running parallel with the axis of the cylinder and may be raised only by using a generally long, flat key provided with a plurality of irregular teeth and alternating indentations along a single edge thereof. For this reason, the number of pin tumblers which may be used and the variations of alternative heights of said pin tumblers within the cylinder is extremely limited.

Another disadvantage of such cylinder locks which can generally accommodate only from four to six laterally spaced pin tumblers is that due to the lateral arrangement of the several pin tumblers, the lock becomes very susceptible to "picking" or opening without the use of the proper key.

In addition, the flat key can be placed in the slot-like opening of the cylinder in only one way, which can be very frustrating for children and especially irritating when trying to unlock a door from an unlighted area where the exact position of the slot is not readily ascertainable.

Furthermore, as the flat key can be inserted only in one position, there is much wear on the toothed face of the key, causing the lock to "stick" and generally become harder to open as time goes on.

Also, the flat key is very susceptible to breakage after being inserted into the cylinder, often necessitating the complete replacement of the entire lock.

Another disadvantage of the flat key is that there are many sharp edges which may prove hazardous to children and which occasionally cause tears in pockets and clothing.

In accordance with this invention, there is provided a cylinder lock adapted to be selectively opened or locked by means of a matching key, comprising an inner cylinder and a stationary outer cylinder, said outer cylinder being provided in a housing, said inner cylinder being rotatably mounted in said outer cylinder, a plurality of bores provided through said cylinders and extending radially from a circular bore which is provided along the axis of said inner cylinder, said radial bores being distributed around the axis of said inner cylinder, a plurality of pin tumblers of various lengths provided one in each radial bore, a plurality of back plugs, a back plug being provided behind each pin tumbler in said bores, a plurality of spring means, one spring means being provided between said housing and each said back plug to urge said pin tumblers toward the axis of said inner cylinder, and a key post provided in said central bore at or adjacent one end thereof, the arrangement being such that when a matching key is inserted into said central bore in a predetermined orientation and from an opposite end of said central bore, each of the plurality of pin tumblers will be raised by the correct amount to bring the top thereof exactly flush with the outer surface of the inner cylinder and by engagement of the key with said key post the inner cylinder may be rotated in response to manual rotation of said key.

Embodiments to be described herein each comprise a cylinder lock and key adapted to provide smoolh operation and easy insertion of said key into the cylinder with a minimum of weal to the surface of the key to provide for a longer useful life thereof.

Owing to the provision of a greatly increased number of pin tumblers which is due to the fact that the pin tumblers are distributed radially around the center axis of the cylinder lock, the lock is much less likely than the ahove-described prior art locks to be successfully picked or opened by means other than the matching key. The key is sturdy and relatively less susceptible to breakage and has a minimum of sharp edges.

Embodiments of this invention will now be described by way of example only with reference to the accompanying drawings. in which: Figiie 1 iS a sicle elevation of a matching cylinder lock and key according to the present invention showing the lock in crosssection; Figure IA is a top view of a key according to the present invention Figure 2 is a view in partial section showing the co-operative engagement of a key and cylinder lock according to the present invention; Figure 3A is a view in partial cross-section showing the position of the pin tumblers when the cylinder lock is in a locked position;; Figure 3B is a similar view thereof show- ing the co-operative engagement between the key. pin tumblers and cylinder as the cylinder lock is unlocked by means of a matching key according to the present in invention Figure 4A is a view in cross-section of a second embodiment of a cylinder lock according to the present invention and Figure 4B is a perspective view of matching key thcrcfor.

Figure l of the drawings shows a cylinder lock 1 () and a matchiig key 15. Said lock 10 is comprised of a housing 1 in which is provided a hollow stationary cylinder 2. The stationary cylinder 2 is provided with a plurality of bores 6 - 6 therethrough. the axes of which are arranged radially around the central axis of the stationary cylinder 2.

Inside the hollow portion of the stationary cylinder 2 is a rotatably mounted inner cylinder 3 hiving a circular bore 5 running longitudinally along ind at a suitable radius about the central axis of the inner cylinder 3 to form a central post 4 of a suitable diameter so that the axis of the post 4 runs congruous with the axis of the inner cylinder 3 and the stationary cylinder 2.

The inner cylinder 3 is provided with a plurality of bores 7 - 7, each bore 7 being in alignment with and having one end communicative with a corresponding bore 6 in the stationary cylinder 2. The other end of each inner bore 7 is provided with an internal flange or stop 8 and is communicative with the circular bore 5.

A plurality of pin tumblers 22 - 22 are provided, one pin tumbler 22 being disposed in each inner bore 7. As shown in the drawings each pin tumbler 22 is generally T shaped in cross-section, ending in a rounded head 22a which extends beyond the stop 8 into the circular bore 5. As shown in Figures 2 and 3A, a back plug 21 is provided which extends between the inner bore 7 and the outer bore 6. A coil spring 20 is disposed in the outer bore 6 and extends between the housing 1 and the plug 21, thereby exerting pressure on the plug 21 and pin tumbler 22 towards the common central axis of the outer and inner cylinders 2 and 3 respectively.

Finally, a key post 9 is disposed between the center post 4 and the stationary cylinder 2 in the manner shown in the drawings.

A lock constructed in accordance with the above requires a key that is adapted to raise all of the radially disposed pin tumblers 22 22 simultaneously to the correct height.

Therefore, a key 15 is provided having a tubular shank 16. That is to say, the round shank 16 is hollow as indicated by the dotted lines in Figures 1 and 1A.

Along the circumference of the shank 16 of the key 15 is provide a plurality of depressions 17 - 17 which correspond to the pin tumblers 22. When the key 15 is inserted into the lock 10 as shown in Figure 2, the tubular shaft 16 will ride over the center post 4. The leading edge 19 of the shaft 16 of the key 15 is tapered so that as the key 15 is inserted over the center post 4 the heads 22a of the pin tumblers 22 - 22 will be urged gently upwardly and over the surface of the key shank 16 as it is fully inserted. The key 15 is inserted into the circular bore 5 and over the center post 4 until a notch or indentation 18 meshes with the key post 9.

In this way exact positioning of the key 15 is obtained so that correct correspondance between the key depressions 17 - 17 and the various pin tumblers 22 - 22 is assured. It is also by virtue of the meshing of the indentation 18 of the key shank 16 and the key post 9 that enables the key, when turned, to cause the inner cylinder 3 to rotate.

As shown in Figure 3A, in the locked position each pin tumbler 22 is in its most forward position and rotation of the inner cylinder 3 is prevented as the back plugs 21 21 are positioned between the stationary cylinder 2 and said inner cylinder 3. However, upon insertion of a matching key 15 as shown in Figure 3B, each pin tumbler 22 is raised off the stop 8 by virtue of the depressions 17 to a point where the top of each pin tumbler 22 is flush with the outer surface of the rotatably mounted inner cylinder 3 so that the cylinder may be rotated with rotation of the key 15 by virtue of the engagement of the indentation 18 with the key post 9.

As shown in Figures 4A and 4B the inner cylinder may be simply a hollow cylinder 3' having an integral tooth or key post 9' formed therein. In this case the key 15' may have a solid shank 16' having a suitable indentation 18' to engage with said key post 9'. While a lock constructed according to this embodiment is as "pick proof" as one according to the first embodiment, the size of the hole may be a temptation to burglars and such to attempt tampering with the lock by inserting various tools therein. The lock would also be much more susceptible to vandalism.Therefor, the inventor feels it advantageous to employ the center post 4 of the first embodiment to provide a genuinely tamper proof lock which is safe, dependable and easy to operate and subject to almost infinite variations in locking combinations of tumblers to provide the maximum protection and peace of mind to the user thereof.

WHAT I CLAIM IS: 1. A cylinder lock adapted to be selectively opened or locked by means of a matching key, comprising an inner cylinder and a stationary outer cylinder, said outer cylinder being provided in a housing, said inner cylinder being rotatably mounted in said outer cylinder, a plurality of bores provided through said cylinders and extending radially from a circular bore which is provided along the axis of said inner cylinder, said radial bores being distributed around the axis of said inner cylinder, a plurality of pin tumblers of various lengths provided one in each radial bore, a plurality of back plugs, a back plug being provided behind each pin tumbler in said bores, a plurality of spring means, one spring means being provided between said housing and each said back plug to urge said pin tumb lers toward the axis of said inner cylinder, and a key post provided in said central bore at or adjacent one end thereof, the arrange ment being such that when a matching key is inserted into said central bore in a predeter mined orientation and from an opposite end of said control bore, each of the plurality of pin tumblers will be raised by the correct amount to bring the top thereof exactly flush with the outer surface of the inner cylinder and by engagement of the key with said key post the inner cylinder may be rotated in response to manual rotation of said key.

2. The cylinder lock of claim 1 wherein each radially arranged bore is provided at its innermost end with a flange.

3. The cylinder lock of claim 2 wherein each pin tumbler is generally in the shape of the letter "T", having a rounded head at the terminus of the stem thereof.

4. The cylinder lock of claim 1 wherein a center post is provided along the axis of said central bore and said key post is disposed between said center post and the inner surface of said inner cylinder.

5. A key adapted for selectively locking and opening a lock as claimed in any preceding claim, said key having a cylindrical shank of approximately the same diameter as the inside diameter of said central bore and is provided with a plurality of depressions distributed over its surface, each depression corresponding to one of said plurality of pin tumblers and adapted for raising each said pin tumbler the correct amount to effect opening of said lock, said shank having a tapered end provided with an indentation for engaging with said key post provided in said lock.

6. The key of claim 5 wherein said shank is hollow and may be inserted over a center post provided in said lock.

7. A cylinder and matching key substantially as herein described with reference to Figures 1 to 3 or Figure 4 of the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. forward position and rotation of the inner cylinder 3 is prevented as the back plugs 21 21 are positioned between the stationary cylinder 2 and said inner cylinder 3. However, upon insertion of a matching key 15 as shown in Figure 3B, each pin tumbler 22 is raised off the stop 8 by virtue of the depressions 17 to a point where the top of each pin tumbler 22 is flush with the outer surface of the rotatably mounted inner cylinder 3 so that the cylinder may be rotated with rotation of the key 15 by virtue of the engagement of the indentation 18 with the key post 9. As shown in Figures 4A and 4B the inner cylinder may be simply a hollow cylinder 3' having an integral tooth or key post 9' formed therein. In this case the key 15' may have a solid shank 16' having a suitable indentation 18' to engage with said key post 9'. While a lock constructed according to this embodiment is as "pick proof" as one according to the first embodiment, the size of the hole may be a temptation to burglars and such to attempt tampering with the lock by inserting various tools therein. The lock would also be much more susceptible to vandalism.Therefor, the inventor feels it advantageous to employ the center post 4 of the first embodiment to provide a genuinely tamper proof lock which is safe, dependable and easy to operate and subject to almost infinite variations in locking combinations of tumblers to provide the maximum protection and peace of mind to the user thereof. WHAT I CLAIM IS:

1. A cylinder lock adapted to be selectively opened or locked by means of a matching key, comprising an inner cylinder and a stationary outer cylinder, said outer cylinder being provided in a housing, said inner cylinder being rotatably mounted in said outer cylinder, a plurality of bores provided through said cylinders and extending radially from a circular bore which is provided along the axis of said inner cylinder, said radial bores being distributed around the axis of said inner cylinder, a plurality of pin tumblers of various lengths provided one in each radial bore, a plurality of back plugs, a back plug being provided behind each pin tumbler in said bores, a plurality of spring means, one spring means being provided between said housing and each said back plug to urge said pin tumb lers toward the axis of said inner cylinder, and a key post provided in said central bore at or adjacent one end thereof, the arrange ment being such that when a matching key is inserted into said central bore in a predeter mined orientation and from an opposite end of said control bore, each of the plurality of pin tumblers will be raised by the correct amount to bring the top thereof exactly flush with the outer surface of the inner cylinder and by engagement of the key with said key post the inner cylinder may be rotated in response to manual rotation of said key.

2. The cylinder lock of claim 1 wherein each radially arranged bore is provided at its innermost end with a flange.

3. The cylinder lock of claim 2 wherein each pin tumbler is generally in the shape of the letter "T", having a rounded head at the terminus of the stem thereof.

4. The cylinder lock of claim 1 wherein a center post is provided along the axis of said central bore and said key post is disposed between said center post and the inner surface of said inner cylinder.

5. A key adapted for selectively locking and opening a lock as claimed in any preceding claim, said key having a cylindrical shank of approximately the same diameter as the inside diameter of said central bore and is provided with a plurality of depressions distributed over its surface, each depression corresponding to one of said plurality of pin tumblers and adapted for raising each said pin tumbler the correct amount to effect opening of said lock, said shank having a tapered end provided with an indentation for engaging with said key post provided in said lock.

6. The key of claim 5 wherein said shank is hollow and may be inserted over a center post provided in said lock.

7. A cylinder and matching key substantially as herein described with reference to Figures 1 to 3 or Figure 4 of the accompanying drawing.