GB2582977A - A locking device - Google Patents

Abstract

A locking device includes a first body, e.g. a shell 10 and a second body e.g. a bobbin 20 both containing recesses which can be aligned and form a split line between the bodies. A cam 44 is attached to the shell and one or more shuttles 46 are located in the recesses and biased towards the cam using preferably via magnets 70 72 with their like poles aligned. When the cam is in a first position the shuttles are pushed outwards, straddle the split line and prevent movement of the bodies, when the cam is in a second position the shuttles retract under the repelling magnetic force, do not straddle the split line and thus the bodies can be moved relative to each other, e.g. rotated. The shuttles preferably are formed with a shuttle head 48 and a shuttle tail 50 which are biased away from each other by a spring so that the head can be compressed towards the tail. The cam may be rotated by a motor 34.

Description

A Locking Device The present invention relates to a locking device and 5 relates particularly, but not exclusively, to an electronically controlled padlock or bike lock device.

The use of electronic locking devices is becoming more widespread and such devices are increasingly included in mobile locking devices such as padlocks and bike locks. Commonly, these locks utilise solenoids or similar devices which utilise combinations of permanent and electromagnets to control the locks. Although generally very effective, these devices can be vulnerable to attempts to manipulate the permanent magnets by the application of very strong magnetic fields around the lock to move the permanent magnets out of a locking condition without using the electromagnets contained within the lock. Mobile locking devices are particularly vulnerable because all sides of the lock can be accessed, allowing multiple magnets to be precisely positioned to manipulate the locks permanent magnets.

Preferred embodiments of the present invention seek to overcome or alleviate the above described disadvantages of the prior art.

According to an aspect of the present invention there is provided a locking device comprising: a first body portion containing a first recess; a second body portion containing a second recess and movable relative to said first body portion creating a boundary adjacent said first and second recesses; at least one cam attached to and movable relative to said first 30 body portion; -2 -at least one shuttle located within said first and second recesses and biased towards said cam, wherein when said cam is in a first condition said shuttle straddles said boundary thereby preventing movement of said first and second body portions relative to one another and when said cam is in a second condition, said shuttle is contained within said first recess and does not straddle said boundary thereby allowing movement of said first and second body portions relative to one another.

By providing a locking device as set out above, the advantage is provided that a locking device can be created which operates electronically and, even if it uses magnets for the purposes of biasing, these magnets cannot be easily manipulated externally to overcome the lock. Furthermore, the lock can be made without the use of magnets or ferromagnetic materials making it impossible to use a magnet to overcome the lock.

The shuttle may further comprise a first shuttle portion engaging said cam and a second shuttle portion, distal ends of said first and second shuttle portions being biased away from 20 each other.

By dividing the shuttle into two separate portions which are biased away from each other, the advantage is provided that the motion of the cam back to the first condition from the second condition is not dependent on the locked or unlocked condition of the locking device. As a result, a sensor, which is otherwise required in order to determine that the lock has returned to the locked condiLion, can be dispensed wiLh. When Lhe cam moves Lo the second condition, which allows the shuttle to be contained within the first recess, the lock can be opened which separates the first and second recesses and will cause the first recess to be closed off by a wall of the second body portion. As the cam rotates back to the first condition, generally after a predetermined period of time, the bias, typically a spring, -3 -between the first and second shuttle portions can be compressed against the wall of the second body portion. When the lock is returned to the locking condition, where the first and second recesses are aligned, the first and second shuttle portions can move away from each other under the force of the spring. Because of the mechanical advantage provided by the cam surface, the spring, which biases the two shuttle portions away from each other, can be quite strong. This helps to ensure that the small magnets contained within the shuttle cannot be used to cause the compression of the spring between the two shuttle portions in order to overcome the lock using a powerful external magnet and without using the key.

In a preferred embodiment the shuttle comprises at least one first magnet and said second body portion comprises at least 15 one second magnet, said first and second magnets arranged to repel one another thereby biasing said shuttle towards said cam.

Using magnets to repel each other as the means for biasing the shuttle towards the cam provides the advantage that when the shuttle is contained within the first recess there is no physical part in the second recess is engaging the shuttle which might cross the boundary between the first and second body portions, leaving the locking device unintentionally locked. As a result, the tolerances of component manufacture required are somewhat less than if a spring-based biasing mechanism were used.

In another preferred embodiment the second shuttle portion comprises said first magnet and said first and second shuttle portions are biased by a spring.

In a further preferred embodiment the biasing between said first and second shuttle portions is stronger than said biasing 30 between said second body portion and said shuttle.

By using magnets to repel the second body portion and shuttle, but using a spring between the first and second shuttle portions and making that this bring stiffer than the biasing -4 -force created by the magnets with their like poles facing the advantage is provided that the simple electronic locking mechanism described can be provided, but the magnet in the shuttle cannot be used to deliberately overcome the lock as the 5 force that can be applied to the magnet externally cannot be sufficient to compress the spring. However, it is still possible to have a simple motor based system which rotates into an unlocked condition for a short and predetermined period of time without the need for sensors to determine that the lock has been 10 returned to a locked condition.

In a preferred embodiment the cam comprises a rotational cam.

In another preferred embodiment the rotational cam as an elliptical cross-section.

In a further preferred embodiment the cam is moved from said first to said second condition by a motor.

By using a rotational cam having an elliptical cross-section that is driven by a motor provides the advantage that a simple motorised mechanism which rotates in a single direction and uses quarter turns to move from a locked condition to an unlocked condition and back again is provided. This creates a low-cost, secure locking device which can be used in a padlock or bike lock without risk of the lock being deliberately overcome using powerful external magnets.

Preferred embodiments of the present invention will now be described, by way of example only, and not in any limitative sense with reference to the accompanying drawings in which:-Figure 1 is a cross-sectional isometric view of a device of the present invention; Figure 2 is an exploded view of the device of figure 1; Figures 3 and 4 are sectional views of the device of figure 1 in locked and unlocked conditions, respectively; -5 -Figures 5 and 6 are plan and isometric views of a rotation cam forming part of the device of figure 1; and Figure 7 is an isometric view of a shuttle of the device of figure 1.

Referring initially to figures 1 and 2, a locking device has a first body portion in the form of a shell which is formed in two halves (labelled 12a and 12b). When formed the shell has two portions, which include an annular main portion 14 and box section 16 (both additionally labelled with the suffixes a and b in the two shell halves). A pair of matching channels 18a and 18b are provided in the main section 14 of shell 12. These have a semicircular cross-section and together form a first recess with a circular cross-section (labelled 18 in figures 3 and 4).

A second body portion, in the form of a bobbin 20, is also provided within the locking device 10. This bobbin 20 is formed with a central shaft 22 and circular ends 24 and 26. When the locking device 10 is assembled, the bobbin 20, sits within the two shell halves 12a and 12b with the axle 22 sitting within a second pair of channels 28a and 28b. As a result, the first and second body portions are movable, specifically rotatable, relative to one another.

Also contained within the bobbin 20 are a pair of second recesses 30. These recesses 30 are most conveniently formed by creating a hole extending through each of the ends 24 and 26 and then partially filling each of those holes with a bung 32 because Lhe bung 32 is noL as long as the hole in Lhe end, 24, 26, Ira° which it is located. The recess 30 is created on the inner side of the end 24 to 26.

The junction of the bobbin 20 within the shell 12 defines a boundary between these two components, particularly at the location of the first and second recesses 18 and 30. This forms a so-called split-line (labelled with the dotted line S). -6 -

Attached to the shell 12 is a motor 34 which drives a rotational cam 36 and is shown in detail in figure 5, the rotational cam 36 has a body portion 38 which is fixed to the output shaft 40 of motor 34 by a fixing screw 42. Extending from the body portion 38 of rotational cam 36 is a cam member 44. As can be seen from figures 5 and 6, the body portion 38 has a circular cross-section and the cam member 44 has an elliptical cross-section.

Contained within the first and second recesses 18 and 30 10 are a pair of shuttles 46. These shuttles are formed from three separate components, namely a shuttle head 48, shuttle tail 50 and a biasing means in the form of a spring 52.

The shuttle tail 50 contains two recesses 54 and 56 which are connected by an aperture 58. The shuttle head 48 has a leg 60 which has a splayed end 62 with a split allowing the splayed end 62 to be slightly compressed. The leg 60 extends through recess 56 and through the aperture 58 with the splayed end being slightly larger than the aperture 58, meaning that the leg is retained within the aperture. The spring 52 is contained within the aperture 56 and presses against a back face 64 of the shuttle head 48. The construction of the shuttle 48 is therefore such that the spring 52 biases the head 48 away from the tail 50 but if the shuttle 46 is compressed the head 48 is able to move towards the tail 50 compressing the spring 52 within the recess 56 until the back face 64 of the head 48 and a front face 66 of the tail 50 engage one another.

The shuttle 46 is biased towards the rotational cam 36 so that a rearmost face 68 of shuttle 46 engages the cam member 44. This biasing is achieved by the inclusion of a pair of magnets 70 and 72 which are arranged with alike poles facing one another so as to repel the magnets away from each other. Magnet 70 is contained within bung 32 and the magnet 72 is contained within the head 48 of shuttle 46. The magnet 70 is set back slightly within bung 32 so that if the shuttle 46 engages the bung 32. The magnets do not engage one another.

A printed circuit board (PCB) 74 is contained within the box section 16 of shell 12 and includes a processor and receiver 5 (not shown) which receive signals from a key and determine whether the lock should be opened. Also on this PCB is a Hall effect sensor 76 which cooperates with four small magnets located in the rotational cam 36. These magnets 78 are located close to the circumference of the circular body portion 38 of 10 the cam 36, each being separated by a quarter of that circumference. The Hall effect sensor 76 is therefore able to detect quarter rotations of the rotational cam 36 as it is rotated by the motor 34.

The rotation of the bobbin, to release the lock, is controlled by the operator using an external handle (not shown) and this is connected to the bobbin 20 via a rubber clutch 80 which is contained below an end cap 82. The rubber clutch 80 tightly fits into a similarly sized recess in the bobbin 20 so as to grip the sides of that recess. However, if excess turning force is applied to the rubber clutch 80 when the lock is in a locked condition the clutch slips to protect the components, particularly the shell 12, bobbin 20 and shuttles 46.

Operation of the present invention will now be described with particular reference to figures 3 and 4. The locking device 10 operates between two conditions, that is a locked condition shown in figure 3 and an unlocked condition shown in figure 4. The boundary between the shell 12 and the bobbin 20 adjacent the first and second recesses 18 and 30, is described as the split-line and indicated with the dashed line labelled S. When the locking device 10 is in the locked condition, as shown in figure 3, the shuttle 46, and in particular the shuttle had 48, straddles the split-line S. As a result, the shuttle head 48 is partly contained in the first recess 18 in the shell 12 and -8 -partly in the second recess 30 in the bobbin 20. The bobbin 20 and shell 12 are therefore unable to rotate relative to one another. As can be seen in figure 3, the cam member 44 is in a position such that the major axis MI of the elliptical cam member 5 lies parallel to the axis of movement of the shuttles. In other words, the thicker portion of the cam member 44 is pressing the shuttles in an outward direction, causing the shuttles 46 to engage the bungs 32. The shuttles 46 cannot move inwards and the spring 52 in the shuttle 46 prevents the shuttle head 48, 10 from moving towards the cam member 44.

In order to open the locking device 10, a key provides a signal to the processor which responds by opening the lock. The key can be any form of suitable electronic unlocking device and includes a signal received from a mobile phone or similar device.

When the processor receives a signal to unlock, the motor 34 rotates through a quarter turn so that the minor axis M2 of the elliptical cam member 34 is aligned with the axis of movement of the shuttles 46. The quarter turned rotation is controlled by signals received from the Hall effect sensor 76 interacting with one of the four magnets 78 in the body 38 of rotational cam 36.

When the minor axis M2 of the cam member 44 is aligned with the axis of movement of the shuttles 46, as shown in figure 4, the shuttles 46 are able to move away from the bungs 32 and be 25 contained entirely within the first recesses 18, thereby no longer straddling the split-line S. This movement of the shuttles is caused by the repulsive force resulting from the alike alignment of the poles (that is, North next to North or South next to South) of the magnets 70 and 72 in the bungs 32 and shuttle heads 48. With the shuttles no longer straddling the split-line S, the bobbin 20 is able to move, that is rotate, relative to the shell 12. Specifically, a rotational force is -9 -applied to the rubber clutch 80 which transfers this rotational force to the bobbin 20.

After a predetermined period of time (generally a few seconds) the processor causes the rotation of the motor, and therefore the cam 36, through a further 90°. As a result, the major axis MI of the cam member 44 is once again aligned with the axis of movement of the shuttles 46. Tf the first and second recesses 18 and 30 are aligned with each other the cam member 44 pushes the shuttles back into the locked position, as shown in figure 3. However, if the bobbin 20 has been rotated and has not been rotated back to the point where the first and second recesses are aligned, the shuttles 46 are unable to re-enter the first recesses 18. Instead, the rotation of the cam member 44 will press the shuttles into engagement with the inner walls of the ends 24 and 26. This will result in the shuttles tail 50 being pressed towards the shuttle head 48, which cannot move because it is engaged with the ends 24 and 26, causing the shuttle tail to move towards the shuttle head resulting in the compression of the spring 52. The shuttle can therefore be compressed, allowing the rotation of the cam 36, irrespective of whether the first and second recesses are aligned. With the cam member 44 remaining in this condition when the first and second recesses 18 and 30 are once again aligned the shuttle head 48 can move away from the tail 50 as the spring 52 extends.

The shuttle head 48 once again straddles the split-line S returning the locking device 10 to the locked condition.

It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the protection which is defined by the appended claims. For example, the lock described above comprises two shuttles acting in opposite directions. This has advantages in that it makes -10 -the lock significantly more difficult to bump and also makes the application of a strong magnet on one side of the locking device unlikely to result in the movement of the shuttles. This is because even if a sufficiently strong magnet can be applied to force the magnets 72 to compress the spring 52, it is likely to be having the opposite effect on the other magnets 72, causing the device to remain locked.

Furthermore, by choosing relatively weak magnets 70 and 72 and forming the other components of the shuttle from non-ferromagnetic materials. The ability of a magnet to influence the magnet 72 is very limited. This is particularly the case if the biasing force applied by the spring 52 is significantly greater than the biasing force provided by the magnets 70 and 72. However, this dual shuttle alignment is not essential, and a single shuttle arrangement or multiple shuttles working in the same direction could be created. This is particularly the case where a lock of this type is used in a door or other device where only one side of the lock can be accessed.

The arrangement of shuttles of the present invention can 20 also be used in other locking devices, for example, non-rotational locking devices such as sliding bolts. Further alternatives also include the use of nonrotating cams which utilise linear cam surfaces that can be driven by rotational motors or by other actuator devices. It is also possible to replace the spring 52, with further repelling magnets which apply the biasing force between the shuttle head 48 and shuttle tail 50.

A further alternative is to replace the compressible shuttles 46, with solid shuttles. This requires an alternative processing method where, instead of rotating the motor 34 and cam 36 after a few seconds of the lock being open irrespective of the alignment or otherwise of the first and second recesses, the motor only rotates back to the condition when the cam member 44 has its major axis MI aligned with the direction of movement of the shuttles 46 (figure 3) when the recesses 18 and 30 are aligned.

Claims (8)

1. -12 -Claims 1. A locking device comprising: a first body portion containing a first recess; a second body portion containing a second recess and movable 5 relative to said first body portion creating a boundary adjacent said first and second recesses; at least one cam attached to and movable relative to said first body portion; at least one shuttle located within said first and second 10 recesses and biased towards said cam, wherein when said cam is in a first condition said shuttle straddles said boundary thereby preventing movement of said first and second body portions relative to one another and when said cam is in a second condition, said shuttle is contained within said first recess and does not straddle said boundary thereby allowing movement of said first and second body portions relative to one another.
2. 2. A locking device according to claim 1, wherein said shuttle further comprises a first shuttle portion engaging said cam and 20 a second shuttle portion, distal ends of said first and second shuttle portions being biased away from each other.
3. 3. A locking device according to claim 1 or 2, wherein said shuttle comprises at least one first magnet and said second body portion comprises at least one second magnet, said first and second magnets arranged to repel one another thereby biasing said shuttle towards said cam.
4. 4. A locking device according to claim 3, wherein said second shuttle portion comprises said first magnet and said first and second shuttle portions are biased by a spring.
5. 5. A locking device according to any of claims 2 to 4, wherein said biasing between said first and second shuttle portions is -13 -stronger than said biasing between said second body portion and said shuttle.
6. 6. A locking device according to any of the preceding claims wherein said cam comprises a rotational cam.
7. 7. A locking device according to claim 6, wherein said rotational cam as an elliptical cross-section.
8. 8. A locking device according to any of the preceding claims wherein said cam is moved from said first to said second condition by a motor.