AU2003255210A1 - Improved dual bladed lock - Google Patents

Description

P001 Section 29 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: IMPROVED DUAL BLADED LOCK The following statement is a full description of this invention, including the best method of performing it known to us: IMPROVED DUAL BLADED LOCK TECHNICAL FIELD The present invention relates to lock cylinders adapted to receive a dual bladed key, to an improvement to such a key, and in particular to an arrangement suitable to in-line lock cylinders.

BACKGROUND ART A widely used lock mechanism is the in-line cylinder lock. This lock has a number of pins, typically six, arranged so as to project from the cylinder plug outward into the barrel. The pins are biased down into the keyway of the lock.

Upon the insertion of a suitable key, the pins (initially of different heights) are aligned so as to permit release of the lock.

The simplicity of such a lock, and the reasonable level of security it affords, has ensured that this is a very popular arrangement. However, the number of combinations available is severely limited. It is possible to have more pins however, if the pins become too small in diameter, this reduces the security of the lock. Increasing the number of same size pins lengthens the associated hardware which is required, and given that much of lock hardware is of a standardised size and configuration, this makes it difficult to achieve adoption of any such changes, other than in specialised applications.

The traditional approach used to increase the master key capacity of six pin in-line systems is the use of profiling. Profiling requires that.ridges and grooves of various shapes are formed on one or other surface of the key. Whilst such systems have been widely adopted, they have a number of inherent limitations. More than one profile may, apart from the intended master keying, inadvertently fit a variety of locks. Excessive profiling may also reduce the strength of the key leading to operational difficulties.

Accordingly, it is an object of the present invention to provide a plug assembly for an in-line cylinder lock, and an improved in-line cylinder lock, which provides greater numbers of combinations and improved possibilities for master keying relative to conventional in-line lock, but which is compatible with existing in-line lock hardware.

It is a further object to provide a key for such a lock which is capable of duplication using conventional lock cutting equipment.

SUMMARY OF THE INVENTION According to one aspect, the present invention comprises a plug assembly for a cylinder lock, said lock having a shell of the type including multiple apertures extending substantially perpendicularly to the keyway, said apertures being substantially in a single line, said plug assembly including a keyway having at least two passages each adapted to receive a key blade, each passage having associated bores extending to the passage from the outside of the shell, said bores being adapted to receive a biased pin, wherein said pins are formed having a first portion adapted to engage one of said apertures, and a second offset portion adapted to be received in one of said bores, the bores and the pins being so arranged that the offset portion may be inserted in two alternative positions so as to insert the pin into one or other of said passages, the arrangement being such that whichever said position is selected, the first portion of each of said pins is operatively adapted to interact with said apertures so as to lock or release said lock.

Broadly, the present invention utilises a cylinder of similar type in principle to the Bi-Lock product marketed by the applicant. The similarity is that dual blades are provided, so that more combinations are provided within a relatively shorter length. However, the present invention differs substantially from the existing Bi-Lock arrangements in that, for example in a dual six pin system, only six of the twelve bores are utilised. The pins are formed in an offset manner, so that whether the left or right key passage is selected for insertion of a pin, the upper end of the offset pin is adapted to engage conventional six pin shells and hardware. Accordingly, the present invention can readily be retrofitted to existing six pin in-line hardware, providing a significantly improved number of combinations and hence improve security, without the expense of changing lock hardware.

The key is preferably formed from two flat blade sections,. joined by a standard connection member. Each flat section can accordingly be separately cut on conventional key cutting equipment, and then joined to form the dual bladed key.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described with reference to the accompanying drawings, in which Figure 1 is an exploded perspective view; Figure 2 is a perspective view of a key blade section; Figure 3 is a plain view of the offset pin; Figure 4 is a perspective view of the offset pins; Figure 5 is a plain view showing the bores for the pin; Figure 6 is a view partly in section, showing the differential depth of the parts of the bores; Figure 7 shows a suitable keyhead; and Figure 8 shows the assembly for the key.

DESCRIPTION

It will be appreciated that the present invention is intended principally for use in association with existing in-line lock hardware. The skilled worker in the field will be familiar with the construction and operation of such hardware, and accordingly it will not be described in detail.

Figure 1 showsthe key 10, plug 20 and shell 40. Key 10 includes two blade sections 12, 13, a joining member 14 and handle 11. An uncut blade section 12 can be seen in figure 2.

Considering figures 7 and 8, key 10 is formed from blade sections 12 and 13 which are attached using projections 15 to the joining member 14. Handle section 11 is slotted into the joining member 14. It will be appreciated that operatively, the blade sections 12, 13 are cut to the required code. They are preferably of dimensions such that they can be cut using conventional key cutting equipment, possibly using a suitable mounting arrangement.

Plug 20 includes body 21, and bores 30 which will be described in more detail below. A keyway 22 suitable for the key 10 is provided in the plug 20. Pins are received into bores 30 and biased downward by springs 38.

From figures 5 and 6, each bore 30 can be seen to have 3 components.

Central bore 32 does not extend the full depth to the keyway. Bores 31 and 33 extend to the keyway, as can be seen from figure 6. In this. implementation, the diameter of bore 32 is greater than the other bores 31, 33.

Pin 35 can be seen in more detail in figures 3 and 4. Each pin has an upper portion 36 and a lower part 37, offset from each other. The diameter of the upper portion 36 is such as to fit within bore 32, and the diameter of the lower portion 37 within bore 31 or 33.

Lower portion 37 is intended to engage the cuts on key blades 12, 13 in use, as with a conventional system. The point of the pin 38 may be conical as shown, a chisel shape or any other suitable shape.

In use, when the plug is being coded, the height of the lower portion 38 will vary to provide the required coding, with corresponding changes in the height of the key cut, as in conventional systems. However, a further feature of the present invention is that the pin may be inserted either into bore 31 or 33. This in turn determines whether it is responsive to a cut on the key blade inserted into the left or right side of the keyway. It will be appreciated that this significantly increases the coding and master keying possibilities relative to a conventional in-line system.

The upper portion 36 is of a size equivalent to a conventional pin of an inline system, so that it will interact with the shell 40 and apertures 41 as if the plug was a conventional six pin in-line plug.

It will be appreciated that variations and additions are possible within the scope of the present invention. For example, profiling could be provided on the blanks. Additional features known in the art could be added to the plug.

Alternative shapes could be used for the bores and pins. More than two blades could be used, although this is not preferred. All of these can be used within the general inventive concepts disclosed.

Claims (7)

1. A plug assembly for a cylinder lock, said lock having a shell of the type including multiple apertures extending substantially perpendicularly to a keyway, said apertures being substantially in a single line, said plug assembly including a keyway having at least two passages each adapted to receive a key blade, each passage having associated bores extending to the passage from the outside of the shell, said bores being adapted to receive a biased pin, wherein said pins are formed having a first portion adapted to engage one of said apertures, and a second offset portion adapted to be received in one of said bores, the bores and the pins being so arranged that the offset portion may be inserted in two alternative positions so as to insert the pin into one or other of said passages, the arrangement being such that whichever said position is selected, the first portion of each of said pins is operatively adapted to interact with said apertures so as to lock or release said lock.

2. The plug assembly of claim 1, wherein the second offset portion of said pins has a smaller diameter than the first portion.

3. A key for use with the plug assembly according to claim 1 or 2, said key including separate blade sections for each passageway, wherein said blade sections are secured in a parallel configuration by a joining member.

4. The key according to claim 3, further including a handle section.

The key according to claim 3 or 4, wherein each said blade section is so dimensioned as to allow each blade section to be cut using conventional key cutting equipment.

6. A plug assembly for a cylinder lock substantially as herein described with reference to any of the accompanying drawings. 6

7. A key for use in a plug assembly for a cylinder lock substantially as herein described with reference to any of the accompanying drawings. DATED this 21st day of October 2003 AUSTRALIAN LOCK COMPANY PTY LTD WATERMARK PATENT TRADE MARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN. VIC. 3122.