Patent Description:
<CIT> shows a padlock which includes a lock body, a shackle having two legs and a locking mechanism for locking the shackle to the lock body. The locking mechanism comprises a rotatable cam and two locking balls. When the padlock is in locked status, the locking balls are engaged with notches of the first and second shackle legs. When the lock is in unlocked status, the cam is rotated to a position where the two locking balls are located corresponding to recesses formed in the cam, so that the locking balls are able to be located in the recesses, and the shackle can be pulled upward until the first shackle leg is completely removed from the lock body. The shackle is replaceable by use of a tool.

However, this padlock may be considered bulky. Also, replacement of the shackle may be considered cumbersome.

<CIT> describes a padlock that includes a locking mechanism with two roller or ball shaped locking elements and a blocker. The blocker is movable between a locked position and an unlocked position. In the unlocked position, the blocker is received in a release cavity of a rotatable latch member.

An object of the present invention is to provide a compact padlock.

Another object of the present invention is to provide a compact padlock that can be operated independently by two different keys.

According to a first aspect of the invention, this and other objects are achieved, in full or at least partly, by a padlock comprising a lock body, a shackle having two shackle legs, a locking mechanism for locking the shackle to the lock body, a selectively rotatable lock core, wherein said lock core is arranged to operate said locking mechanism for locking and unlocking the padlock, wherein said locking mechanism, contrary to the state of the art, comprises at least three locking elements in the form of at least three locking balls which, when the locking mechanism is in a locked state, are disposed side by side in a first direction extending between a first locking element recess formed in the first shackle leg and a second locking element recess formed in the second shackle leg. Said padlock further comprises a rotatable member being attached to said lock core and comprising a retaining portion, which is configured to retain a first locking ball of the locking mechanism in a locking position when said lock core is situated in a first lock core position, and a release cavity which is configured to, upon rotation of said lock core from its lock core position to a second lock core position, receive said first locking element, wherein said release cavity is configured to allow movement of the first locking ball in a second direction, which is different from said first direction, from its locking position to a non-locking position in which the shackle is disengaged from the lock body, thereby allowing withdrawal of the shackle.

A compact padlock is provided, since the locking element is arranged to be moved in a second direction upon unlocking. Hence, the retaining portion of the rotatable member only need to, in a locked state, support the first locking ball to prevent it from moving in the second direction and do not need to block the locking balls from lateral displacement, which enables a compact solution. Especially, a compact solution as seen in the first direction is provided. In the locked state the first locking ball thus itself holds the other locking balls in place and prevents them from leaving their respective locking recesses. Also, a padlock with a high level of security is enabled, since unlocking movement of each of said locking balls is mechanically blocked by the retaining portion of the rotatable member. It it thus not possible to move any of the locking balls from its locking position using e.g. a picking tool and/or padlock shims. In fact, rotation of the rotatable member, to such extent that the locking element cavity is to at least some extent exposed to the first locking ball, is required to disengage the shackle from the lock body. Furthermore, a compact padlock, and/or a padlock having a simple design, in which two different locking devices can be used independently of each other to disengage the shackle from the lock body is enabled. When the padlock is situated in an upright position the first direction corresponds to a horizontal direction.

According to one embodiment said release cavity is configured to, upon rotation of said lock core from its first lock core position to its second lock core position, completely receive said first locking ball, which provides for a very compact solution.

According to one embodiment said second direction is orthogonal to said first direction. In this embodiment, when the padlock is situated in an upright position the first direction corresponds to a horizontal direction and the second direction corresponds to a vertical direction.

Each of said locking elements is thus a ball.

According to one embodiment said lock core form part of an electromechanical lock. Such an electromechanical lock may be configured to be operated by a programmable key, in the form of a physical programmable key configured to be inserted into a key receptacle of the electromechanical lock cylinder, or in the form of a mobile device, such as a mobile phone, which mobile device is configured to communicate with a lock core rotation device of the electromechanical lock.

According to one embodiment said rotatable member comprises a guiding surface which is configured to, upon rotation of said lock core, move the first locking ball from its non-locking position to its locking position.

According to one embodiment at least one release member forms a positioning element configured to, when the first locking ball is situated in its locking position, hold the first locking element in an offset position relative to the other locking elements.

In this embodiment, the release member is a non-movable member which holds the first locking element pre-positioned in such a position that movement thereof is initiated upon rotation of the first lock core. The non-movable member thus forms a static member of the padlock. The non-movable release member may be formed integral with or secured to the lock body. The retaining portion of the rotatable member may then, if the retaining portion is flat, be arranged such that the first locking ball is situated vertically below the other locking balls, i.e. in an offset position, as seen when the padlock is situated in an upright position, i.e. in a position in which the visible portion of shackle is located vertically above the lock body. Alternatively, the retaining portion may be formed with a recess, the depth of which is adapted to hold the first locking ball in such an offset position.

According to one embodiment said locking mechanism comprises at least five locking balls which, when the locking mechanism is in a locked state, are disposed side by side in said first direction, and said padlock further comprising a second selectively rotatable lock core, arranged to independently operate said locking mechanism for locking and unlocking the padlock, and a second rotatable member being attached to said second lock core and comprising a retaining portion, which is configured to retain a second locking ball of the locking mechanism in a locking position when the second lock core is in a first lock core position, and a release cavity which is configured to, upon rotation of the second lock core from the first lock core position to a second lock core position, receive said second locking ball, wherein said second rotatable member is configured to allow movement of said second locking ball in the second direction from its locking position to a non-locking position in which the shackle is disengaged from the lock body, thereby allowing withdrawal of the shackle.

A first opening device, such as a programmable key in the form of a physical key or in the form of a mobile device, may operate the first locking device and a second opening device, such as a mechanical key, may operate the second locking device. In this embodiment the padlock may thus be unlocked by a key inserted in the key receptacle of a first lock or by a key inserted in the key receptacle of a second lock. A padlock that is possible to independently operate with two different keys is thus achieved. Furthermore, each rotatable member provides for a robust and reliable operation of the locking mechanism.

According to one embodiment said first shackle leg is formed with a circumferential groove, a first recessed portion between the first locking element recess and the circumferential groove, and a second recessed portion which extends from said circumferential groove and terminates at the outermost part of the free end of said second shackle leg. The second recessed portion permits the shackle to be completely withdrawn from the lock body without the use of a tool. This has the advantage that the shackle of a padlock can be replaced by a replacement shackle in a very easy and fast manner. Such a replacement shackle may e.g. be a shackle providing larger clearance between the body and the shackle. The same lock body may thus be used together with shackles having different clearance between the shackle and the lock body.

According to one embodiment at least one of said release members comprises a magnetic element.

Further advantages and characteristics of the invention emerge from the description below and from the following patent claims.

The invention will be described in more detail with reference to the appended schematic drawings, which show examples of presently preferred embodiments of the invention.

The invention will now for the purpose of exemplification be described in more detailed by means of examples and with reference of the accompanying drawings, in which currently preferred embodiments of the invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and to fully convey the scope of the invention to the skilled addressee.

<FIG> illustrate a padlock <NUM> according to a first embodiment of the invention. The padlock <NUM> comprises a lock body <NUM>, formed by a first lock body part 3a and a second lock body part 3b, a shackle <NUM> having a first shackle leg <NUM> and a second shackle leg <NUM>. The first shackle leg <NUM> is longer than the second shackle leg <NUM>. The lock body <NUM> has a first shackle leg bore <NUM> for receiving the first shackle leg <NUM> and a second shackle leg bore <NUM> for receiving the second shackle leg <NUM>. The first lock body part 3a further has a first locking device bore <NUM> for receiving a first locking device and a second locking device bore <NUM> for receiving a second locking device. In this embodiment the first locking device is an electromechanical lock <NUM>, and the second locking device is a mechanical cylinder lock which comprises a mechanical lock cylinder <NUM>.

The electromechanical lock <NUM> comprises a first lock core <NUM> which is received in the first locking device bore <NUM>. The first lock core <NUM> is selectively rotatable with respect to a combination of the first lock body part 3a and a locking device part <NUM> in a known manner. The first lock core <NUM> is provided with a key receptacle <NUM> for receiving a programmable key.

A first rotatable member <NUM> is attached to the first lock core <NUM>. The first rotatable member <NUM> comprises a first retaining portion <NUM> and a first release cavity <NUM>, as illustrated in <FIG>. In this embodiment, the first rotatable member <NUM> further comprises a first guiding surface <NUM> which is disposed in connection to the first release cavity <NUM>. The first rotatable member <NUM> is attached to the first lock core <NUM> so as to rotate therewith upon rotation thereof. The guiding surface <NUM> raises from the bottom surface of the first release cavity <NUM> to the first retaining portion <NUM>. In other words the first guiding surface <NUM> connects the the bottom surface of the first release cavity <NUM> and retaining surface of the first retaining portion <NUM>.

The mechanical lock cylinder <NUM> comprises a lock cylinder body <NUM> and a second lock core <NUM> located within the lock cylinder body <NUM>. The second lock core <NUM> is provided with a key receptacle <NUM> for receiving a key and is selectively rotatable with respect to the lock cylinder body <NUM>.

A second rotatable member <NUM> is attached to the second lock core <NUM>. The second rotatable member <NUM> comprises a retaining portion <NUM> and a release cavity <NUM>, as illustrated in <FIG>. In this embodiment, the second rotatable member <NUM> further comprises a second guiding surface <NUM> which is disposed in connection to the second release cavity <NUM>. The second rotatable member <NUM> is attached to the second lock core <NUM> so as to rotate therewith upon rotation thereof. The second guiding surface <NUM> raises from the bottom of the second release cavity <NUM> to the second retaining portion <NUM>. In other words the second guiding surface <NUM> connects the the bottom surface of the second release cavity <NUM> and the retaining surface of the second retaining portion <NUM>.

The padlock <NUM> further comprises a locking mechanism <NUM> for locking the shackle <NUM> to the lock body <NUM> in order to place the padlock <NUM> in a locked state. The locking mechanism <NUM> comprises a first locking element recess <NUM>, which is formed in the first shackle leg <NUM>, a second locking element recess <NUM>, which is formed in the second shackle leg <NUM>, and locking elements <NUM> in the form of locking balls <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. A first locking ball <NUM> is arranged to be supported by the first retaining portion <NUM> when the first lock core <NUM> is situated in a first lock core position. A second locking ball <NUM> is arranged to be supported by the second retaining portion <NUM> when the second lock core <NUM> is situated in a first lock core position. When both lock cores <NUM>, <NUM> are situated in their respective first lock core positions, as illustrated in <FIG>, the padlock <NUM> is in a locked state. In the locked state, the locking balls <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are disposed side by side in such a manner that adjacent locking balls are in contact with each other. Then, the locking balls <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are disposed side by side in a first direction extending between the first locking ball recess <NUM> and the second locking ball recess <NUM>. When the padlock <NUM> is situated in an upright position the first direction corresponds to a horizontal direction.

A third locking ball <NUM> is arranged to be received in the first locking element recess <NUM> and engage the wall thereof. A fourth locking ball <NUM> is arranged to be received in the second locking ball recess <NUM> and engage the wall thereof. A fifth locking ball <NUM> is disposed between the first <NUM> and second <NUM> locking balls. The three intermediate locking balls <NUM>, <NUM>, <NUM> are configured to maintain the third locking ball <NUM> in the first locking ball recess <NUM> and the fourth locking ball <NUM> in the second locking ball recess <NUM> when the padlock <NUM> is in its locked state.

As illustrated in <FIG>, a locking ball cavity <NUM> is formed in the second lock body part 3b. The locking ball cavity <NUM> is configured to receive the locking balls <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the locking mechanism <NUM>.

The padlock <NUM> further comprises a shackle retaining device <NUM> for retaining a portion of the shackle <NUM> within the lock body <NUM> to maintain the shackle <NUM> connected to the lock body <NUM> when the padlock <NUM> is unlocked. The retaining device <NUM> comprises a spring-biased connecting element, in the form of a spring-biased ball <NUM>, which is received in a cavity <NUM> formed in the second lock body part 3b. To this end, a compression spring <NUM> is arranged between the connecting element <NUM> and a support surface <NUM>. The support surface <NUM> is in this case formed by a plug <NUM> which is secured to the second lock body part 3b. The connecting element <NUM> is arranged to be biased against a first flat portion <NUM> of the first shackle leg <NUM>.

At the free end 7a of the first shackle leg <NUM> a circumferential groove <NUM> is formed. The circumferential groove <NUM> is configured to receive the spring-biased ball <NUM> of the shackle retaining device <NUM> to allow rotation of the shackle <NUM> relative the lock body <NUM>. The first flat portion <NUM>, which provides a bearing surface to the spring-biased ball <NUM> upon withdrawal of the shackle <NUM>, extends from the first locking ball recess <NUM> to the circumferential groove <NUM>. The depth to which the first flat portion <NUM> is recessed in to the first shackle leg <NUM> is approximately the same as the depth of the circumferential groove <NUM>.

At the free end 7a of the first shackle leg <NUM> a second flat portion <NUM> is formed. The second flat portion <NUM> extends from the circumferential groove <NUM> and terminates at the outermost portion of the free end 7a. The first flat portion <NUM> and the second flat portion <NUM> are formed on opposite sides of the first shackle leg <NUM>.

The padlock <NUM> further comprises a first release arrangement <NUM> and a second release arrangement <NUM>. The first release arrangement <NUM> is received in a recess <NUM> formed in the second lock body part 3a at the bottom of the locking ball cavity <NUM> and the second release arrangement <NUM> is received in a second recess <NUM> formed in the second lock body part 3a at the bottom of the locking ball cavity <NUM>.

Now referring to <FIG>, the first release arrangement <NUM> comprises a release member, in the form of a spring-biased ball <NUM>, as illustrated in the enlarged part of <FIG>. The spring-biased ball <NUM> is arranged to apply a force on the first locking ball <NUM> and thereby press the first locking ball <NUM> against the retaining portion <NUM> of the first rotatable member <NUM>.

Now referring to <FIG>, the second release arrangement <NUM> comprises a release member, in the form of a spring-biased ball <NUM>, as illustrated in the enlarged part of <FIG>. The spring-biased ball <NUM> is arranged to apply a force on the second locking ball <NUM> and thereby press the third locking ball <NUM> against the retaining portion <NUM> of the second rotatable member <NUM>.

With reference to <FIG>, unlocking of the padlock <NUM> with an appropriate programmable key <NUM> inserted in the key receptacle of the electromechanical lock cylinder <NUM> will be described hereinafter.

The programmable key <NUM>, which is used to operate the electromechanical lock <NUM>, comprises an energy source, such as a battery, and a control unit powered by the energy source. The key <NUM> can access a cloud based or locally hosted access control system which transfer authorization data to the key or log information from the key <NUM> to the access control system via internet and a synchronization unit or via a mobile communication system such as the GSM net and a mobile device, such as a mobile phone. In one embodiment the mobile device is the key itself. The key <NUM> access the synchronization unit or the mobile device by a physical contact, by near field communication, such as NFC, or by radio communication, such as Bluetooth. The key <NUM> can store all data necessary to access at least one specific electromechanical lock <NUM>, but cannot access any electromechanical locks for which it does not have the appropriate authorization data. Locking and unlocking of a lock using the programmable key <NUM> is rendered possible only if the programmable key is synchronized appropriately via the synchronization unit or a mobile device. Further, the programmable key <NUM> is provided with means by which electrical power, data and mechanical effort can be transmitted to the lock in a known manner. The electromechanical lock <NUM> is configured to be powered by and communicate with the programmable key <NUM> upon the insertion of the key <NUM> in the key receptacle <NUM>. To this end the electromechanical lock <NUM> comprises power receiving means, communication means, access control device for controlling access of a key <NUM> inserted in the key receptacle <NUM> and an electrical control unit.

<FIG> illustrates the padlock <NUM> in a locked state. In this state, the third locking ball <NUM> engages the wall of the first locking ball recess <NUM> and the fourth locking ball <NUM> engages the wall of the second locking ball recess <NUM>. Further, in the locked state, the first locking ball <NUM> is situated in a locking position, in which it is supported by the first retaining portion <NUM>, and the second locking ball <NUM> is situated in a locking position, in which it is supported by the second retaining portion <NUM>. Also, in the locked state, the fifth locking ball <NUM>, which is disposed between the first locking ball <NUM> and the second locking ball <NUM>, prevents the other locking balls <NUM>, <NUM>, <NUM> from being displaced laterally. Hence, the intermediate locking balls <NUM>, <NUM>, <NUM> together prevent the third and fourth locking balls <NUM>, <NUM> from being displaced from their respective locking ball recesses <NUM>, <NUM>. When the padlock is in the locked state the locking balls are disposed side by side in the first direction.

Upon rotation of the first lock core <NUM>, and thereby the first rotatable member <NUM>, in an unlocking direction using the programmable key <NUM>, as illustrated by arrows A in <FIG>, the first release cavity <NUM> is exposed to the first locking ball <NUM>. Then, the first locking ball <NUM> is free to move in a second direction, which is orthogonal to the first direction, from its locking position into the first release cavity <NUM>, as schematically illustrated by arrow B in <FIG>. In this embodiment, the first locking ball <NUM> is forced to move away from its locking position by the releasing member <NUM>, as illustrated by arrows C and D in the enlarged part of <FIG>. The movement of the first locking ball <NUM> away from its locking position is thus initiated by the spring-biased ball <NUM> which exerts a force on the first locking ball <NUM>.

The third locking ball <NUM> and the fourth locking ball <NUM> are then free to move out of the first locking element recess <NUM> and the second locking element recess <NUM>, respectively, as illustrated by arrows E and F in <FIG>, which allows the shackle <NUM> from to be withdrawn, as illustrated by arrows G in <FIG>, to place the padlock <NUM> in an unlocked state. The shackle <NUM> is withdrawn until the spring-biased ball <NUM> is received in the circumferential groove <NUM>, as best illustrated in <FIG>. Then, the second shackle leg <NUM> is completely withdrawn from the lock body <NUM> while the first shackle leg <NUM> is still within the shackle leg bore <NUM> and connected to the lock body <NUM> by the shackle retaining device <NUM>.

The first lock core <NUM> is thus rotated to permit movement of the locking balls <NUM>, <NUM>, <NUM>, <NUM>, <NUM> for disengaging the shackle <NUM>, thereby permitting movement of the shackle <NUM> in a direction away from the lock body <NUM> and removal of the shorter leg <NUM> from the corresponding shackle leg bore <NUM> for placing the padlock <NUM> in an unlocked state. The locking mechanism <NUM> thus comprises locking elements, in the form of locking balls <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, each of which is movable between a locking position, in which it, together with the other locking elements, prevents the shackle <NUM> from being withdrawn from the lock body <NUM>, and a releasing position in which it permis the shackle <NUM> from being withdrawn from the lock body <NUM>.

With reference to <FIG> locking of the padlock <NUM> will be described hereinafter. Upon rotation of the first lock core <NUM> in the opposite direction, as illustrated by arrows H in <FIG>, the first locking ball <NUM> is moved back to its locking position under the guidance of the first guiding surface <NUM>, as illustrated by arrows I in <FIG>. The guiding surface <NUM> of the first rotatable member <NUM> is thus configured to, upon rotation of the first lock core <NUM> in a locking direction, which is opposite to the unlocking direction, move the first locking ball <NUM> to its locking position. Upon this movement, each locking ball <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is forced to its respective locking position, i.e. the third locking ball <NUM> is moved into the first locking ball recess <NUM>, the fourth locking ball <NUM> is moved into the second locking ball recess <NUM> and the intermediate locking balls <NUM>, <NUM>, <NUM> are moved into positions in which they together prevent the third <NUM> and fourth <NUM> locking balls from being displaced from their respective locking ball recesses <NUM>, <NUM>.

With reference to <FIG>, unlocking of the padlock <NUM> with an appropriate mechanical key <NUM> inserted in the key receptacle of the mechanical lock cylinder <NUM> will be described hereinafter. <FIG> illustrates the padlock <NUM> in the locked state, which has been described hereinbefore with reference to <FIG>.

Upon rotation of the lock core of the mechanical cylinder <NUM>, and thereby the second rotatable member <NUM>, in an unlocking direction using the key <NUM>, as illustrated by arrows J in <FIG>, the first release cavity <NUM> is exposed to the second locking ball <NUM>. Then, the second locking ball <NUM> is free to move in a second direction, which is orthogonal to the first direction, from its locking position into the second release cavity <NUM>, as schematically illustrated by arrow K in <FIG>. In this embodiment, the second locking ball <NUM> is forced to move away from its locking position by the releasing member <NUM>, as illustrated by arrows L and M in the enlarged part of <FIG>. The movement of the second locking ball <NUM> away from its locking position is thus initiated by the spring-biased ball <NUM> which exerts a force on the second locking ball <NUM>.

The third locking ball <NUM> and the fourth locking ball <NUM> are then free to move out of the first locking cavity <NUM> and the second locking cavity <NUM>, respectively, as illustrated by arrows N and O in <FIG>, which allows the shackle <NUM> from to be withdrawn, as illustrated by arrows P in <FIG>, to place the padlock <NUM> in an unlocked state. The shackle <NUM> is withdrawn until the spring-biased ball <NUM> is received in the circumferential groove <NUM>. Then, the second shackle leg <NUM> is completely withdrawn from the lock body <NUM> while the first shackle leg <NUM> is still within the shackle leg bore <NUM> and connected to the lock body <NUM> by the shackle retaining device <NUM>.

Upon rotation of the lock core of the mechanical cylinder <NUM> in an opposite direction, the second locking ball <NUM> is moved back to its locking position under the guidance of the second guiding surface <NUM>. The second guiding surface <NUM> is thus configured to, upon rotation of the second lock core <NUM> in a locking direction, which is opposite to the unlocking direction, guide the second locking ball <NUM> to its locking position. Upon this movement, each locking ball <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is forced into its respective locking position, i.e. the third locking ball <NUM> is moved into the first locking ball recess <NUM>, the third locking ball <NUM> is moved into the second locking ball recess <NUM> and the intermediate locking balls <NUM>, <NUM>, <NUM> are moved into positions in which they together prevent the third <NUM> and fourth <NUM> locking balls from being displaced from their respective locking ball recesses <NUM>, <NUM>.

The first rotatable member <NUM> may thus be operated by an appropriate key inserted into the key receptacle of the electromechanical lock and the second rotatable member <NUM> may be operated by an appropriate key inserted into the key receptacle of the mechanical lock cylinder <NUM>. Each of the lock cores <NUM>, <NUM> is thus arranged to independently operate the locking mechanism for locking and unlocking the padlock <NUM>.

The release cavities <NUM>, <NUM> thus enables the third locking ball <NUM> and the fourth locking ball <NUM> to be moved from the first locking ball recess <NUM> and the second locking ball recess <NUM>, respectively and thereby the locking mechanism to be moved to an unlocking position in which it permits withdrawal of the shackle <NUM> from the lock body <NUM>.

Now referring to <FIG>, the first shackle leg <NUM> is provided with a second flat portion <NUM> that serves to facilitate replacement of a shackle <NUM> by a replacement shackle. The second flat portion <NUM> extends from the circumferential groove <NUM> to the outermost portion of the free end 7a of the second shackle leg <NUM>. The depth to which the second flat portion <NUM> is recessed in to the first shackle leg <NUM> is less than the depth of the circumferential groove <NUM>. This provides for some resistance to withdrawal of the shackle <NUM>. A predetermined force is thus needed to withdraw the shackle completely in order to secure that the shackle is not detached from the lock body in an undesirable manner. In this embodiment the depth to which the second flat portion <NUM> is recessed in to the first shackle leg <NUM> is about half of the depth of the circumferential groove <NUM>.

In this embodiment the first flat portion <NUM>, illustrated in <FIG>, and the second flat portion <NUM> are situated on opposite sides of the first shackle leg <NUM>, as best illustrated in the enlarged part of <FIG>.

With reference to <FIG>, replacement of a shackle <NUM> is described hereinafter. In a first step, the shackle <NUM> to be replaced is rotated as illustrated by arrow Q in <FIG>. The shackle <NUM> is rotated, with the spring-biased connecting ball <NUM> disposed in the circumferential groove <NUM>, <NUM>° to a shackle changing position. In the shackle changing position, illustrated in <FIG>, the connecting element <NUM> faces the side of the shackle leg <NUM> that has the second flat portion <NUM>. Hence, by rotating the shackle <NUM>°, the second flat portion <NUM> is exposed to the connecting ball <NUM>. When the shackle <NUM> is situated in the shackle changing position, which is illustrated in <FIG>, the shackle <NUM> is permitted to be completely withdrawn from the lock body <NUM>, as illustrated by arrow R in <FIG>. Upon such withdrawal of the shackle <NUM>, the connecting element <NUM> abuts the second flat portion <NUM>, as illustrated in the enlarged part of <FIG>.

In a second step, the shackle <NUM> is completely withdrawn from the lock body, as illustrated by arrow S in <FIG>.

In a third step, the longer shackle leg <NUM> of a replacement shackle <NUM>, e.g. a shackle with more clearance between the shackle <NUM> and the lock body <NUM>, can be inserted into the first shackle leg bore <NUM>, as illustrated by arrows T in <FIG>, and used together with the lock body <NUM> in the manner previously described for the replaced shackle <NUM>. Upon insertion of the replacement shackle <NUM> it is oriented such that the second flat surface <NUM> of the longer shackle leg <NUM> faces the spring-biased ball <NUM> of the shackle retaining device <NUM>.

Hereinafter a padlock <NUM> according to a second embodiment will be described with reference to <FIG>. Many features disclosed in the first embodiment are also present in the second embodiment with similar reference numerals identifying similar or same features. Having mentioned this, the description will focus on explaining the differing features of the second embodiment.

The second embodiment differs from the first embodiment in that the padlock <NUM> comprises one single lock core <NUM> instead of two lock cores.

The single lock core <NUM> is selectively rotatable with respect to a combination of a first lock body part 203a and a locking device part <NUM>, illustrated in <FIG>. The lock core <NUM>, which is configured to receive a physical programmable key <NUM>, form part of an electromechanical lock <NUM>. A rotatable member <NUM> is secured to the lock core <NUM> so as to rotate therewith upon rotation thereof. The rotatable member <NUM> comprises a first retaining portion <NUM> and a release cavity <NUM> and a guiding surface <NUM> which is disposed in connection to the first release cavity <NUM>.

Furthermore, the padlock <NUM> differs in that the locking mechanism for locking the shackle <NUM> to the lock body <NUM> comprises only three locking elements, in the form of three locking balls <NUM>, <NUM>, <NUM>. The locking mechanism thus comprises a first locking element recess <NUM>, which is formed in the first shackle leg <NUM>, a second locking element recess <NUM>, which is formed in the second shackle leg <NUM>, and locking elements in the form of three locking balls <NUM>, <NUM>, <NUM>. A first locking ball <NUM> is arranged to be supported by the retaining portion <NUM> of the rotatable member <NUM> when the lock core <NUM> is in a first lock core position. When the lock core <NUM> is in its first lock core position the padlock <NUM> is in a locked state. Then, the locking balls are disposed side by side in a first direction extending between the first locking element recess <NUM> and the second locking element recess <NUM> in such a manner that the first locking ball <NUM> is in contact with each of the second locking ball <NUM> and the third locking ball <NUM>.

A second locking ball <NUM> is arranged to be received in the first locking element recess <NUM> and engage the wall thereof and a third locking ball <NUM> is arranged to be received in the second locking ball recess <NUM> and engage the wall thereof. The first locking ball <NUM>, i.e. the intermediate locking ball, is configured to maintain the second locking ball <NUM> in the first locking ball recess <NUM> and the third locking ball <NUM> in the second locking ball recess <NUM> when the padlock <NUM> is in its locked state.

Unlocking and locking of the padlock <NUM> with an appropriate programmable key <NUM> inserted in the lock core <NUM> is carried out in the same manner as described hereinbefore with reference to <FIG>.

It will be appreciated that many variants of the above-described embodiments are possible within the scope of the appended patent claims.

Claim 1:
Padlock (<NUM>; <NUM>) comprising
a lock body (<NUM>; <NUM>),
a shackle (<NUM>) having two shackle legs (<NUM>, <NUM>),
a locking mechanism (<NUM>) for locking the shackle (<NUM>) to the lock body (<NUM>; <NUM>),
a selectively rotatable lock core (<NUM>),
wherein said lock core (<NUM>) is arranged to operate said locking mechanism (<NUM>) for locking and unlocking the padlock (<NUM>),
wherein said locking mechanism comprises at least three locking balls (<NUM>, <NUM>, <NUM>) which, when the locking mechanism is in a locked state, are disposed side by side in a first direction extending between a first locking element recess (<NUM>) formed in the first shackle leg (<NUM>) and a second locking element recess (<NUM>) formed in the second shackle leg (<NUM>),
said padlock further comprising a rotatable member (<NUM>) being attached to said lock core (<NUM>) and comprising a retaining portion (<NUM>), which is configured to retain a first locking ball (<NUM>) of the locking mechanism (<NUM>) in a locking position when said lock core (<NUM>) is situated in a first lock core position, and a release cavity (<NUM>) which is configured to, upon rotation of said lock core (<NUM>) from its first lock core position to a second lock core position, receive said first locking ball (<NUM>),
wherein said release cavity (<NUM>) is configured to allow movement of the first locking ball (<NUM>) in a second direction, which is different from said first direction, from its locking position to a non-locking position in which the shackle (<NUM>) is disengaged from the lock body (<NUM>; <NUM>), thereby allowing withdrawal of the shackle (<NUM>).