WO2010102326A1

WO2010102326A1 - A padlock

Info

Publication number: WO2010102326A1
Application number: PCT/AU2010/000258
Authority: WO
Inventors: James Stewart
Original assignee: Stewart, Donald, Charles
Priority date: 2009-03-12
Filing date: 2010-03-09
Publication date: 2010-09-16

Abstract

An improved padlock (100) includes anti breaking and anti picking features. In particular, the padlock (100) includes a casing (200); an axial pin tumbler lock cylinder (300) attached to the casing (200) and including a rotatable spindle (308) having a threaded shank (324); and a shackle (400) having a threaded leg portion (402) that is threadingly engageable with the shank (324) of the lock cylinder (300) to lock the shackle (400) to the casing (200).

Description

TITLE A PADLOCK

FIELD OF THE INVENTION The present invention relates generally to locks, and particularly to a padlock having improved security features.

BACKGROUND

Padlocks have long been used to lock a variety of equipment. A padlock generally comprises a casing, a lock cylinder fixed in the casing, and a shackle releasably lockable relative to the casing. However, as long as there are locks there will be people who try to break or pick them.

Padlocks can be broken by brute force. As an example, a hardened steel drill bit directed down a lock cylinder and powered by a cordless drill can stealthily and quickly sheer off the pins of many conventional padlocks, rendering the padlock easily opened.

Padlocks also may be broken by brute force applied to the mechanism which engages the shackle and locks the shackle to the casing. Common locking mechanisms are balls which are actuated in and out of engagement with notches in the shackle by the lock cylinder. If enough force is applied between the shackle and the casing, such locking mechanisms will generally fail.

Padlocks also may be picked. However, it is generally accepted that axial pin tumbler locks are less prone to picking. Therefore there is a need for an improved padlock with anti breaking and anti picking features.

SUMMARY OF THE INVENTION In one form, although it need not be the only or indeed the broadest form, the invention resides in a padlock comprising: a casing; an axial pin tumbler lock cylinder attached to the casing and including a rotatable spindle having a threaded shank; and a shackle having a threaded leg portion that is threadingly engageable with the shank of the lock cylinder to lock the shackle to the casing.

Preferably, the lock cylinder includes a pin cylinder and the spindle includes a spindle cylinder, wherein the spindle cylinder abuts the pin cylinder with the shank of the spindle extending through a central hole in the pin cylinder.

Preferably, an interface between the spindle cylinder and the pin cylinder is a shear plane of the lock cylinder.

Preferably, the spindle cylinder has spindle-holes in which combination pins are slidably received and the pin cylinder has pin-holes in which constant-length pins are received, wherein the spindle-holes have a larger bore than the pin-holes so that there is a shoulder at the interface between the spindle-holes and the pin-holes.

Preferably, the combination pins have a base which is dimensioned to engage the shoulder at the interface between the spindle-holes and the pin- holes at a maximum stroke of the combination pins in the spindle-holes.

Preferably, the shank of the lock cylinder has a male thread and the leg portion of the shackle has a female thread.

Preferably, the lock cylinder includes an anti-drill disc at one end of the cylinder housing to discourage drilling of the housing. Preferably, the padlock includes a detachable key.

In this specification, including the claims, the terms "comprises," "including," "comprising" or similar terms are intended to mean a nonexclusive inclusion, such that an apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be readily understood and put into practical effect, reference will now be made to preferred embodiments as illustrated with reference to the accompanying drawings, wherein like reference numbers refer to like elements, in which:

FIG. 1 is a schematic diagram illustrating a cross-sectional view of one embodiment of a padlock in accordance with the invention in a locked configuration;

FIG. 2 is a schematic diagram illustrating the padlock of FIG. 1 in a configuration where the shank is released from the lock cylinder;

FIG. 3 is a schematic diagram illustrating a cross-sectional view of the lock cylinder of the padlock of FIG. 1 , sectioned along section line Ill-Ill of FIG.5;

FIG. 4 is a schematic diagram illustrating a cross-sectional view of the lock cylinder of the padlock of FIG. 1 , sectioned along section line IV-IV of FIG. 5;

FIG. 5 is a schematic diagram illustrating a bottom view of the lock cylinder of the padlock of FIG. 1 ;

FIG. 6 is a schematic diagram illustrating an exploded perspective view of the lock cylinder of the padlock of FIG. 1 ;

FIG. 7 is a schematic diagram illustrating a perspective view of a key of the padlock of FIG. 1 ; FIG. 8 is a schematic diagram illustrating a cross-sectional view of the key of FIG. 7; and

FIG. 9 is a schematic diagram illustrating a perspective view of the shackle of the padlock of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG's 1 and 2, there is a schematic diagram illustrating a cross-sectional view of a padlock 100 according to a preferred embodiment of the present invention. The padlock 100 comprises a casing 200, a lock cylinder 300, a shackle 400 and a key 500. FIG. 1 shows the shackle 400 locked to the casing 200 by the lock cylinder 300 and FIG. 2 shows the shackle 400 released from the lock cylinder 300. The casing 200 has two passages 202, 204, in which leg portions 402,

404, respectively, of the shackle 400 are slidably received. The passage 202 has an enlarged lower section in which the lock cylinder 300 is fixed. One end of the lock cylinder 300 abuts an internal shoulder 206 of the casing 200 at a juncture between the enlarged lower section and the rest of the passage 202. The lock cylinder 300 is attached to the passage 202 by a rollover formation 208, which abuts the other end of the lock cylinder 300. The leg portion 404 of the shackle 400 is captured in the passage 204 by a pin 210. A nose part of the pin 210 extends into a longitudinal groove 406 in the leg portion 404, thereby to capture the shackle 400 while still allowing for limited sliding displacement of the shackle 400 relative to the casing 200.

FIG's 3 and 4 are schematic diagrams illustrating cross-sectional views of the lock cylinder 300 according to a preferred embodiment of the present invention. FIG. 5 is a bottom view of the lock cylinder 300. FIG. 3 shows a cross sectional view of the lock cylinder 300 sectioned along section line Ill-Ill of FIG. 5. FIG. 4 shows a cross sectional view of the lock cylinder 300 sectioned along section line IV-IV of FIG. 5. The lock cylinder 300 is an axial pin tumbler lock cylinder. The lock cylinder 300 comprises a cylinder housing 302 having a central axis, an anti-drill disc 304; washer 306; spindle 308; pin cylinder 310; compression spring 312; and a lock ring 314. The lock cylinder 300 has a shank end 316 and a key end 318.

The cylinder housing 302 has rollover portions 320 at its ends to hold the components of the lock cylinder 300 together. The washer 306 abuts the rollover portion 320 at the key end 318 and the lock ring 314 abuts the rollover portion 320 at the shank end 316. The anti-drill disc 304 seats against the washer 306. The spindle 308 comprises a spindle cylinder 322 and a shank 324. The spindle cylinder 322 abuts the anti-drill disc 304 on one side and the pin cylinder 310 on the other side. The interface between the spindle cylinder 322 and the pin cylinder 310 is a shear plane 338 for the lock cylinder 300. The shank 324 of the spindle 308 extends through the pin cylinder 310 and the lock ring 314. The shank 324 is male threaded at its distal end region. The compression spring 312 slides over the shank 324 and is positioned between the lock ring 314 and the pin cylinder 310 to keep all of the components of the lock cylinder 300 seated against each other.

The spindle cylinder 322 has five spindle-holes 326 in which combination pins 328 are slidably received. The combination pins 328 each comprise a cylindrical base 330 and spigots 332 projecting from the base 330. The bases 330 have a diameter which is slightly less than the bore of spindle-holes 326 and the spigots 332 have a diameter of slightly less than the bore of pin-holes 334 of the pin cylinder 310. The spindle-holes 326 of the spindle cylinder 322 have a larger bore than the pin-holes 334 of the pin cylinder 310. The spindle cylinder 322 is orientated relative to the pin cylinder 310 so that the pin-holes 334 are aligned with the spindle-holes 326. As such, there is a shoulder 336 at the interface between the spindle-holes 326 and the pin-holes 334, which the base 330 of the combination pins 328 engage when the combination pins 328 are at maximum stroke in the spindle-holes 326. The spigots 332 may all be of different length. The base 330 engaging the shoulder 336 prevents a lock picker from sounding the relative lengths of the spigots 332 by testing the maximum travel of the combination pins 328.

The pin cylinder 310 has a central hole 343 through which the shank 324 of the spindle 308 extends. The pin cylinder 310 includes constant- length pins 340 and pin springs 344 located in its pin-holes 334. The pin holes 334 do not extend all the way through the pin cylinder 310 and have blind ends 335 against which the pin springs 344 seat. The pin springs 344 are positioned between the blind ends 335 and the constant-length pins 340 so that the constant length pins 340 are forced against the combination pins 328. The constant-length pins 340 sit across the shear plane 338, thereby to lock the spindle 308 to the pin cylinder 310. The pin cylinder 310 is fixed in the cylinder housing 302 by a key 303 which extends between corresponding holes in the sides of the cylinder housing 302 and pin cylinder 310. In order for the spindle 308 to be rotated relative to the cylinder housing 302, the combination pins 328 need to push the constant-length pins 340 into the pin- holes 334 to a depth where the juncture between the combination pins 328 and the constant-length pins 340 are at the shear plane 338 in an unlocked configuration of the lock cylinder 300. Due to the different lengths of the spigots 332 of the combination pins 328, each combination pin 328 has to be displaced a different predetermined distance to align with the shear plane 338. The combination pins 328 are displaced in the spindle-holes 326 by the key 500, as will be described in more detail herein below.

The anti-drill disc 304 has holes 342 defined therein, which are arranged to align with the spindle-holes 326 of the spindle cylinder 322.

In the unlocked configuration of the key cylinder 300, the combination pins 328 are displaced by the key 500.

Referring to FIG's 7 and 8, the key 500 comprises a key body 502 and key pins 504 having different length prongs 506. The key pins 504 are embedded in the body 502 with the prongs 506 projecting from a face 508 of the key 500. The length of the prongs 506 can be varied by addition of a key combination disc 512 (shown in FIG 8 only) which effectively alters the distance from the tips of the prongs 506 to the face 508. The key pins 500 are arranged in the same pattern as the holes 342 in the anti-drill disc 304. The pattern is that of circularly arranged evenly spaced holes/pins with one hole/pin position skipped. This allows for the key 500 to only be inserted into the lock cylinder 300 in a particular orientation. In use, the prongs 506 are aligned with the holes 342 in the anti-drill disc 304. The key 500 is then inserted into the lock cylinder 300 so that the prongs 506 extend through the holes 342 and into the spindle-holes 326 to displace the combination pins 328. Each combination pin 328 is displaced a predetermined distance by the prongs 506 so that ends of all of the spigots 332 of the key pins 328 are simultaneously at the shear plane 338 in the unlocked configuration of the lock cylinder 300. The key 500 has a hole 510 extending through the body 502 so that key chain can be affixed to the key 500.

In use, the shank 324 screws into the leg portion 402 of the shackle 400 to lock the shackle 400 to the lock cylinder 300 as depicted in FIG.1. To release the shackle 400 from the lock cylinder 300, the key 500 is inserted into the lock cylinder 300 and the spindle 308 rotated anti-clockwise by the key 500 to unscrew the shackle from the spindle 308 as depicted in FIG. 2. Similarly, to lock the shackle 400 to the lock cylinder 300, the end of the leg portion 402 is brought into engagement with the distal end of the shank 324 and the spindle 308 is rotated clockwise with the key 500 to thread the shank 324 into the shackle 400.

Referring to FIG. 9, the shackle 400 has a female thread 418 machined into the leg portion 402, and the shank 324 of the spindle 308 threads into the female thread 418. The longitudinal groove 406 in the leg section 404 ends at an annular groove 408. When the shackle 400 is released from the lock cylinder 300, the shackle can be displaced axially as the nose of the pin 210 slides in the longitudinal groove 406 and the shackle 400 is allowed to rotate when the nose of the pin 210 is received in the annular groove 408.

The anti-drill disc 304 is designed to spin in the cylinder housing 302 should any attempt be made to drill out the entire lock cylinder 300 with a relatively large bore drill. In such an event a drill bit would bind on the anti- drill disc 304, stopping the bit from drilling into the lock cylinder 300.

The anti-drill disc 304 and the variable length combination pins 328 provide dual protection against attempts to defeat the lock through drilling. As discussed above, the anti-drill disc 304 is a deterrent to relatively large bore drill bits that would seek to drill out the entire lock cylinder 300.

Similarly the variable length combination pins 328 are a deterrent to relatively smaller bore drill bits that would seek to drill out each of the constant length pins 340. Such a small bore drill bit placed against an outer end of a key pin 328 causes the pin 328 to simply rotate in its respective spindle-hole 326, and thus no drilling progress can be made. The padlock 100 is resistant to brute force attacks because of the shackle 400 being threaded into the shank 324 to lock the shank 324 relative to the casing 200. Screw-threaded engagement between the shackle and the lock cylinder 300 provides a secure locking mechanism.

Those skilled in the art will recognise that the components of the present invention are preferably manufactured from high strength metals, although alternative materials may be used. For example the key 500 is preferably made of lightweight, high-strength plastic encasing high strength metal key pins 504. The anti-drill disc 304 is preferably made of tungsten or high strength steel. The present invention is therefore an improved drill resistant padlock that includes numerous inventive and useful features over the prior art. Those skilled in the art will recognize useful features of the invention in addition to those described above.

The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. Accordingly, this patent specification is intended to embrace all alternatives, modifications and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention.

Claims

1. A padlock, comprising: a casing; an axial pin tumbler lock cylinder attached to the casing and including a rotatable spindle having a threaded shank; and a shackle having a threaded leg portion that is threadingly engageable with the shank of the lock cylinder to lock the shackle to the casing.

2. The padlock of claim 1 , wherein the lock cylinder includes a pin cylinder and the spindle includes a spindle cylinder, wherein the spindle cylinder abuts the pin cylinder with the shank of the spindle extending through a central hole in the pin cylinder.

3. The padlock of claim 2, wherein an interface between the spindle cylinder and the pin cylinder is a shear plane of the lock cylinder.

4. The padlock of claim 2, wherein the spindle cylinder has spindle-holes in which combination pins are slidably received and the pin cylinder has pinholes in which constant-length pins are received, wherein the spindle-holes have a larger bore than the pin-holes so that there is a shoulder at the interface between the spindle-holes and the pin-holes.

5. The padlock of claim 4, wherein the combination pins have a base which is dimensioned to engage the shoulder at the interface between the spindle-holes and the pin-holes at a maximum stroke of the combination pins in the spindle-holes.

6. The padlock of claim 1 , wherein the shank of the lock cylinder has a male thread and the leg portion of the shackle has a female thread.

7. The padlock of claim 1 , wherein the lock cylinder includes an anti-drill disc at one end of the cylinder housing to discourage drilling of the housing.

8. The padlock of claim 1 , wherein the padlock includes a detachable key.