Patent Description:
Rotary combination dial locks are widely used for securing lock mechanisms such as a strap locks, padlocks or lock boxes. Combination locks are in general a lightweight but reliable method to secure items without the need for keys.

An example of this is using a combination lock connected to a strap for securing a bike to a bike rack. As a combination dial can contain vast numbers of numerical combination variations the user can be assured that their bike should be safe. However, there are a number of individuals who can unlock the strap lock without knowing the combination by understanding how the lock sounds or feels when a digit is correctly entered. This decreases the level of security of the lock and increases the level of uncertainty a user may feel when they are wanting to secure their personal possessions.

Examples of the prior art are disclosed in the patent applications published under the numbers <CIT>, <CIT>, <CIT> and <CIT>.

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 mechanism comprising a clasp and a clasp receiver for engaging and locking with each other, the clasp receiver comprising:.

By providing a combination lock which utilises pins straddling a shear line and by connecting a clasp to a clasp receiver, the advantage provided is a loop lock, such as a strap lock, chain lock or padlock. This type of combination lock, because it works differently from standard combination locks, is harder to overcome and presents different challenges to anyone attempting to interfere or open the lock without knowing the combination.

In a preferred embodiment the pin receiver portion further comprises a first aperture and at least one fixing device extending through the first aperture for securing the digit portion to the pin receiver portion.

Having a fixing device for securing every clasp receiver to the digit portion increases the level of security for the combination device as all the fixing devices would have to be damaged or forcefully removed.

In another preferred embodiment the clasp receiver further comprises a blocking device biased in a third direction by a third biasing member, wherein when all the first pins are in the unlocked condition the blocking device is movable to allow access to the digit portion and enable manipulation of the fixing device and release the digit portion from the pin receiver portion thereby allowing the combination of the lock to be changed.

Unlike other combination dial locks this blocking device prevents access to the fixing member such as a screw when in a locked condition. This prevents any unlawful tampering with the fixing member and therefore avoids someone, other than the owner, changing the combination or unlocking the device.

The blocking device also acts as a barrier to stop moisture or rain getting into the mechanism from the underside preventing rust build up around the fixing member and other moving parts such as the latch member which could cause it to get stiff or unusable.

In a further preferred embodiment at least one second pin is biased by a fourth biasing member in a fourth direction towards said combination dial wherein said combination dial comprises at least one second recess corresponding to each digit of said digit portion for engaging said second pin and said fourth biasing members act on said second pins with greater force than said second biasing members on the first pins.

Having a second pin acting on the digit portion for every turn of the digit portion masks the feeling and the sound of the first pin moving into place in the pin receiver portion. This provides an extra security feature and would deter someone tampering with the combination lock because it is more difficult to feel or hear the movement of the first pin. The recesses also act as an additional grip for the user when they are turning the digit portion.

In another preferred embodiment the second recesses are located on the digit portion.

In an additional preferred embodiment, the first pins are split pins.

In a preferred embodiment a pushing member is used to control the position of the latch member to release the clasp when all the plurality of first pins are in an unlocked condition.

According to another aspect of the present invention there is provided a lock comprising:.

In a further aspect of the present invention there is provided a locking mechanism comprising:.

By providing fixing devices for each of the combination dials and a blocking device the advantage is provided that the lock can only be changed by accessing them through the space created by the movement of the blocking device. Thus, a very secure mechanism, utilising materials such as hardened steel for the blocking device, can be provided to prevent interference with the dials.

In a preferred embodiment of the present invention the pins comprise split pins.

In another preferred embodiment of the present invention a pushing member is used to control the position of the latch member to release a clasp associated with said locking mechanism when all the plurality of first pins are in an unlocked condition.

The second pins are used to prevent there being a perceivable difference in the feeling of the first pins engaging the correct position in the dial.

In a preferred embodiment of the present invention the fourth biasing member acts on the second pin with a greater force than the second biasing member on the first pin.

In particular, the use of extra force in the biasing member that impacts the.

In another preferred embodiment of the present invention the at least one second recess is located on the digit portion.

In a further preferred embodiment of the present invention the first and second pins comprise split pins.

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:.

Initially referring to <FIG> a combination strap lock <NUM> includes a locking mechanism <NUM> and a strap <NUM>. At one end of the strap is a clasp <NUM> and the other end has a clasp receiver <NUM>. When in a locked condition the clasp <NUM> engages with the clasp receiver <NUM> creating a loop with the strap <NUM>. With additional reference to <FIG> the clasp receiver includes two sections, a body <NUM> and a latch member <NUM> both contained within a housing <NUM>. The latch member <NUM> and the body <NUM> form a shear line <NUM> between one another with the latch <NUM> biased in a first direction D1 by a first biasing member <NUM>. When in a locked condition, a pair of first protrusions <NUM> located on the latch <NUM> enter into a pair of clasp recesses <NUM> on the clasp <NUM>. It should be noted however that the first protrusions <NUM> could be located on the clasp <NUM> and the clasp recesses <NUM> located on the latch <NUM>. Furthermore, the recesses and protrusions could be replaced by a single recess and protrusion like a seat belt tongue or by T-shaped bar that could hook around a pair of protrusions. In between the clasp recess <NUM> is a button recess <NUM> through which a mechanical button <NUM> makes contact with the latch member <NUM>. In an unlocked condition the button <NUM> is pressed pushing down on the latch member <NUM> towards the first biasing member <NUM> and releasing the pair of first protrusions <NUM> from the clasp recesses <NUM> thereby releasing the clasp <NUM> from the clasp receiver <NUM>.

Even though the button <NUM> is an integral part of the latch member <NUM> in the above embodiment, it could be a replaced by a separate button that would act indirectly with the latch member. This could be achieved via levers attached to the button and latch member <NUM>. Once the button is pressed it would indirectly move the latch member <NUM> via these levers.

Located at the boundary between the latch member <NUM>, and the body <NUM> are a plurality of first split pins <NUM> being biased by a second biasing member <NUM> in the form of a helical spring in a second direction D2. The first split pins <NUM> have a first left portion <NUM> and first right portion <NUM>, forming a first coupling joint <NUM> when together. When in an unlocked condition the first right portion <NUM> is located within a first pin recess <NUM> within the latch <NUM> and the first left portion <NUM> is located within a first pin aperture <NUM> within the body <NUM>. Furthermore, the first pins <NUM> do not straddle the shear line <NUM> and the coupling join <NUM> is in line with the shear line, allowing the latch <NUM> to move when the button <NUM> is pressed. When in a locked condition the first split pins <NUM> straddle the shear line <NUM>, therefore the coupling join <NUM> is not in line with the shear line and the latch cannot move when the button <NUM> is pressed. When in a locked condition a proportion of the first left portion <NUM> crosses the shear line <NUM> thereby stopping the latch <NUM> from being moved when the button <NUM> is pressed. It is noted that in the above example split pins have been described. However, non-split pins with a longer biasing member that engages the end of the non-split pin could be used. In this instance, the shear line would be defined by the join between the non-split pin and the biasing member (spring).

Contained within the body <NUM> are a plurality of combination dials <NUM>, in <FIG> it can be seen that there are four combination dials. These combination dials <NUM> further include a digit portion <NUM> and a pin receiver portion <NUM>. The digit portion <NUM> is a circular disk and includes the numbers <NUM> to <NUM> around the circumference with each digit having a second recess <NUM> either side. The digit portion <NUM> could also have any combination of letters, numbers or special characters around the circumference. The pin receiver portion <NUM> is an annular disk and includes a first recess <NUM> that engages with the first left portion <NUM> of the first split pins <NUM>. The pin receiver <NUM> also includes a first aperture <NUM> and a first fixing device in the form of grub screw <NUM>. The grub screw <NUM> extends through the first aperture <NUM> and makes contact with a second fixing device <NUM>. The second fixing device <NUM> fits within the hole of the annular pin receiver portion <NUM> and is connected to the digit portion via a bar <NUM>. The second fixing device <NUM> is gear shaped and has a third recess <NUM> corresponding to every digit on the digit portion <NUM>. For example, if the digit portion has numbers <NUM> to <NUM> there are ten third recesses <NUM>, one recess for every turn of the digit portion. When the grub screw <NUM> is inserted through the first aperture <NUM> of the pin receiver portion <NUM>, the end or tip of the grub screw slots into one of the third recesses <NUM> of the second fixing device <NUM> whilst the body of the grub screw <NUM> is retained in the pin receiver portion <NUM>. This secures the second fixing device <NUM> to the pin receiver portion and in turn secures the pin receiver portion <NUM> to the digit portion <NUM>. Therefore, when the digit portion <NUM> is turned from one number to another the second fixing device <NUM> and pin receiver portion <NUM> also turn by the same proportion. When in a locked condition the grub screw <NUM> is inaccessible and is covered by a blocking device <NUM>, whereby third apertures are also located within the body adjacent the blocking device <NUM>.

The blocking device <NUM> is made from a hardened steel and biased in a third direction D3 by third biasing members <NUM> in the form of a helical springs towards the latch member <NUM>. It should be noted that even though D3 is parallel to D2 (although acting in the opposite direction), if the shape of the body was different or larger the springs could act on the blocking device transversely or at an angle relative to D2. The blocking device <NUM> also includes a series of finger recesses <NUM>, with each finger recess corresponding to a single first aperture <NUM> on the pin receiver portion <NUM>. That is, the transverse distance between each of the finger recesses <NUM> is the same as the transverse distance between each of the first apertures <NUM>. This ensures that when the finger recesses <NUM> and first apertures are lined up, with the first apertures <NUM> above the finger recesses <NUM>, they create unrestricted access between the base of the blocking device and the first apertures <NUM> to the grub screws <NUM>. In between each finger recess <NUM> is a finger protrusion <NUM>. These finger protrusions <NUM> are inserted part way into the third biasing members <NUM> so to move the blocking device <NUM> smoothly when in an unlocked condition. When in a locked condition the blocking device <NUM> is prevented from movement by the clasp <NUM>. In particular, a blocking device extension <NUM>, which is fixed to the blocking device <NUM>, engages with the clasp <NUM> when the clasp <NUM> to prevent any movement of the blocking device until the mechanism <NUM> is unlocked and the clasp has been removed.

To allow the user access to the blocking device <NUM> there is a third aperture <NUM> at the base of the housing <NUM> that aligns with the finger recesses <NUM> of the blocking device when in an unlocked condition. When not in use this aperture <NUM> is concealed by a plug <NUM> that is removable.

The digit portion <NUM> also engages a second split pin <NUM>. This second split pin <NUM> also includes a second right and left portion also forming a second coupling joint <NUM> when together. The second right portion <NUM> is adjacent a fourth biasing member <NUM> in the form of a spring located with the latch <NUM>, biasing the second split pin <NUM> in a fourth direction D4 towards the digit portion <NUM>. The second left portion <NUM> has a head that fits the shape of the third recess <NUM> of the digit portion <NUM>. When the head of second split pin <NUM> engages the third recess <NUM>, the second split pin does not straddle the shear line <NUM>, between the latch <NUM> and the body <NUM>, allowing the second coupling joint <NUM> to align with the shear line <NUM>. With every turn of the digit portion <NUM> from one number to the next the head of the second split pin <NUM> will always have a recess to engage and therefore the second coupling joint <NUM> will align with the shear line <NUM>. When the digit portion is moved in between two numbers (that is, the head of the second split pin is not engaging a third recess <NUM>) the second coupling joint <NUM> will not be aligned with the shear line <NUM>. Therefore, the second split pin <NUM> will be straddling the shear line preventing the latch <NUM> from moving.

These second split pins <NUM> are used as decoy split pins and are not important for locking the locking mechanism. The fourth biasing members <NUM> are stronger acting helical springs compared to the second biasing members <NUM> acting on the first split pins. When the digit portions <NUM> are turned from one number to the next, regardless of whether the combination is right the second split pins will always enter into a third recess <NUM>, masking the sound and feel of the first split pins <NUM> entering into the first recess <NUM> of the pin receiver portion <NUM>.

It should again be noted that even though D4 is in the same planar direction as D2 in the embodiment the second split pin could also be rotated or extend from another part of the body. For example, if the body <NUM> was slightly larger or a different shape, the second split pin <NUM> could be located transverse to the digit portion.

Referring again to <FIG> it can be seen that part of each digit portion <NUM> extends above the level of the housing <NUM>. In this figure three digits and two second recesses <NUM> are accessible, allowing a user to turn each digit portion <NUM>. The second recesses <NUM> in this case are also used as gripping points for the user to rotate the numbers on the digit portion <NUM>.

Operation of the locking mechanism will now be described. It should be noted that in <FIG> the locking mechanism <NUM> is shown in an unlocked condition, in which all the first and second spit pins, <NUM> and <NUM>, are not straddling the shear line <NUM> and their coupling joints, <NUM> and <NUM>, are also aligned with the shear line <NUM>. On receiving the strap lock <NUM> (initially in an unlocked condition) the user is prompted to change the numbers on the combination dials <NUM> to a four-digit code that they can easily remember, for example <NUM>-<NUM>-<NUM>-<NUM>. The user will start by pushing the button <NUM> that forces the latch member <NUM> towards the first biasing member <NUM> and releases the clasp <NUM> from the clasp receiver <NUM>. The user is then free to remove the plug <NUM> and gain access to the grub screws <NUM>. The blocking device <NUM>, initially having covered the grub screws <NUM> on the pin receiver portions <NUM>, has now moved in the direction D4 with the clasp <NUM> having been released. The user can then use a screwdriver or other such device to release the grub screw <NUM> from the third recess <NUM> of the second fixing device <NUM>, allowing free movement of the digit portion <NUM> from the pin receiver portion <NUM>. The user is then able to rotate each wheel in turn until they have entered their combination, in this example the combination dials would read <NUM>-<NUM>-<NUM>-<NUM>. Using the screwdriver, the user can screw all the grub screws <NUM> back through the pin receiver portions <NUM> and into their corresponding third recesses <NUM>. With this achieved the strap lock <NUM> can only be unlocked using this combination. The user can input the clasp <NUM> back into the clasp receiver <NUM>. This pushes the blocking device <NUM> back towards the third biasing member <NUM> covering the first apertures <NUM> of the pin receiver portions and thereby covering the grub screws <NUM>. Once the clasp <NUM> is secured in the clasp receiver <NUM> the user replaces the plug <NUM> and can rotate the numbers to any combination, putting the strap lock <NUM> into a locked condition. The first split pins <NUM> will be straddling the shear line <NUM>, preventing any movement of the latch member <NUM> when the button <NUM> is pushed on.

Once the combination <NUM>-<NUM>-<NUM>-<NUM> is entered into the combination dials <NUM> the first split pins <NUM> will no longer be straddling the shear line <NUM>. Allowing movement of the latch <NUM> and therefore the release of the clasp <NUM> from the clasp receiver <NUM>.

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, although the above embodiment is being described as a strap lock it could be used in other situations such as a locking seatbelt or pram. The combination dial could be connected to a separate strap as opposed to being connected to the strap and the clasp receiver.

A further example is the biasing members are in the form of springs and more specifically helical springs, but they could be replaced by opposing magnets, or other type of springs such as a conical disk spring.

Another example is the strap could be replaced by a cable or chain.

A further example is the material of the blocking device is made from. It does not necessarily need to be made from a hardened steel, it could equally be made from a normal steel material or other such metal or plastic.

An additional example is the shape of the blocking device. As described in the embodiment above, the blocking device it has a series of finger protrusions and finger recesses however it would also work if the blocking device had a single recess, a series of apertures or had no recess or apertures but a single block of steel being removed from the locking mechanism or moved aside to allow access.

Claim 1:
A locking mechanism (<NUM>) comprising a clasp (<NUM>) and a clasp receiver (<NUM>) for engaging and locking with each other, said clasp receiver (<NUM>) comprising:
a body (<NUM>);
a latch member (<NUM>) biased in a first direction (D1) by a first biasing member (<NUM>), wherein a boundary between said latch member and said body defines a shear line (<NUM>) and one of said latch member (<NUM>) and said clasp (<NUM>) having at least one protrusion (<NUM>) for selectively engaging the other of said latch member (<NUM>) and said clasp (<NUM>) in locking engagement;
a plurality of first pins (<NUM>) biased in a second direction (D2) transverse to said first direction (D1) by respective second biasing members (<NUM>), wherein said plurality of first pins (<NUM>) move between a locked condition, wherein said plurality of first pins (<NUM>) straddle said shear line (<NUM>), and an unlocked condition, wherein said plurality of first pins (<NUM>) do not straddle said shear line (<NUM>); and
a plurality of combination dials (<NUM>) at least partially contained in said body (<NUM>), said combination dials (<NUM>) comprising a digit portion (<NUM>) and a pin receiver portion (<NUM>), wherein each said combination dial (<NUM>) has an unlocked rotational position in which one of said plurality of first pins (<NUM>) engages a first recess (<NUM>) in said pin receiver portion (<NUM>) moving said one of said plurality of first pins (<NUM>) to said unlocked condition.