Patent Description:
Different locking systems are used in many applications for preventing unauthorized access to compartments. Such compartments may for example be safes, cargo containers, semi-trailers, swap-bodies, truck and van compartments, just to mention a few. A conventional locking system for containers comprise vertical rods extending on an outside of a loading door. The vertical rods are arranged with horizontal locking bolts that fit into fixtures on the frame of the loading door. The locking system is operated by handles attached to the vertical rods, enabling a rotation of the vertical rods between a locking position to a resting position. In order to prevent unauthorized access to the container, pad locks are used for locking the handles, preventing rotation of the vertical rods and thereby opening of the doors.

With the ever-increasing cargo shipment around the globe, often containing different types of goods targeted by thieves and thus goods that are tempting to steal, different solutions regarding trailers and trailer doors have been developed. The most basic are solutions where the handling of the trailer door handles are made more difficult, for instance by covering the area of the pad lock or to mount a sturdy lockable bar that grips around the vertical rods of a door pair. These might reduce the risk of break-in, but they are bulky, heavy and generally not user-friendly.

More recently, for a limited kind of cargo compartments and only where full access to power supply is available, intelligent systems have been launched having ID-functions. One such system comprises a locking system that is attached to a door, in particular doors of containers and in particular lorry and semi-trailer compartments. The locking system comprises a handle on the outside of the door. The handle controls a locking bolt placed on the inside of the door and extending towards and into a recess or passage in the floor or bottom of the trailer container. The handling of the handle is only permitted if a correct code is entered on a keypad. This type of locking system works quite well in most situations.

However, in many applications, considerable force is required to open doors of containers, due to effects from weather, such as water, ice, dirt and cold climate as well as effects due to use like refrigerated containers, washing liquids (acid or basic solutions). Other effects may come from (lack of) service and maintenance, logistic flows, expected life etc. Such conditions may make the locking and bolting arrangement of containers to function very poorly and/or even malfunction and jam, whereby there is a pronounced risk that for instance the handle or other vital components of the above mentioned locking system is broken, rendering it very difficult to open the container. Handles and other critical components can always be damaged on attempts to open as traditional stiff designed connected handle to the locking and blocking system, when locked as well as unlocked. The root cause of the problem is that the design is suffering from the stiff connection. When a very high required force needs to be applied to the handle in order to open, and when the lock/blocking system is locked, the operator can apply unlimited force to the handle until it brakes.

In <CIT> a locking body is disclosed comprising a bolt and a follower that is functionally connectable with the bolt to control the position of the bolt and a driver.

In <CIT> another locking body is disclosed, in which the parts that form the force transmission connection from the spindle shaft of the handle of the lock body to the bolt comprise a spring which transfer force and is used to eliminate the protrusion of the bolt caused by tolerance variations when opening the door.

In <CIT> discloses a door lock arrangement comprising a housing with a latch bolt movable between a protruding and a retracted position. An operation axis is provided at which a follower is installed, and which is turnable by a lock operating device to its retracted position, wherein a spring acts to return the latch bolt to its protruding position.

In <CIT> a door leaf with a bar lock, which has an upwardly and/or downwardly closing bolt and the locking bars. The locking bars are held in opening position by of a catch device, wich triggers the transfer of the locking bars into the closing position only when the catch device senses the closing position of the door leaf or door-leaf wing.

The aim of the present invention is to remedy the drawbacks of the state of the art solutions. This aim is obtained by a locking arrangement having the features of the independent patent claim. Preferable embodiments of the invention form the subject of the dependent patent claims. The invention enables a total control of the force that can be transferred via the handle to the lock and blocking system and prevent any harm to the vital components.

According to the invention, a locking arrangement for releasably locking a door of a compartment according to claim <NUM> is provided. The locking arrangement comprises a locking bolt movable between an extended locking position and a retracted release position, an actuator operably connected to an opening element, where the actuator is rotatable between an initial position and an activated position, and a transmission arranged between the actuator and the locking bolt, the transmission being arranged to move the locking bolt between the extended position and the retracted position when the actuator is rotated.

Furthermore, the transmission comprises a lever arranged pivotable and in contact with the actuator, a pressure arm pivotally attached with one end to the lever and operably connected to said locking bolt, wherein rotation of the actuator causes the lever to pivot and the pressure arm to act on said locking bolt for moving the locking bolt from the extended position to the retracted position.

The actuator comprises an arm, a first roller bearing journalled at a free end of said arm, which first roller bearing is arranged in contact with and run along a surface of the lever. The use of roller bearings reduces the force requirements due to very low friction of the transmission.

Additionally, the pressure arm is arranged with an elongated groove,thatthe locking bolt being arranged with an attachment block attached to the locking bolt, the attachment block being arranged with a second roller bearing arranged to run in said groove. In accordance with the invention, the transmission further comprises a support surface provided with a track and wherein a second end of the pressure arm is arranged to be in contact with and run in the track. With this arrangement, the transmission enables a much-reduced force requirement for moving the locking bolt to the retracted position, which is a great advantage if the locking bolt is somehow jammed or difficult to move. This could for example be due to ice building up inside the compartment, which frequently occurs in refrigerated compartment for transporting frozen goods. It may also be due to misaligned doors wherein the locking bolt may be pressed hard against a surface of the recess that receives the locking bolt. Thus, the risk of breaking components of the locking arrangement due to the need of applying large forces in order to open the door is greatly reduced. In a preferred embodiment, the second end may be arranged with a third roller bearing running in the track. Also, the locking bolt may be arranged with a compression spring arranged to bias the locking bolt in the extended position.

The locking arrangement may further comprise bearing blocks arranged to support said locking bolt. In this regard, the bearing blocks may comprise slide bearings through which the locking bolt is slidably supported, and wherein the slide bearings are arranged in the bearing blocks with a play in transversal directions. With this solution, the locking bolt may enter a receiving recess even if for example the doors and thus the locking arrangement are somewhat misaligned in relation to the fixed structure of the compartment.

These and other aspects of and advantages with the present application will become apparent from the following detailed description and from the accompanying drawings.

Furthermore, a blocking device to be used with a locking system of a closing structure for a compartment is disclosed but not forming part of the claimed invention.

The blocking device comprises an engagement member arranged movable between a non-engaging position out of contact with a locking system and an engaging position enabling operation of the locking system. The blocking device further comprises a blocking arrangement operably connected to the engagement member wherein the blocking arrangement blocks movement of the engagement member in the non-engaging position. Further, an activator is operably connected to said blocking arrangement wherein operation of said activator enables an unblocking of said engagement member by said blocking arrangement. With this arrangement, the blocking device effectively blocks the engagement member so that the locking system cannot be manipulated until the activator is operated and unblocks the engagement member.

The engagement member may comprise an axle arranged movable in a longitudinal direction between the non-engaging position and the engaging position. Further, a first blocking element may be arranged on the axle and a second blocking element may be arranged to the blocking arrangement, arranged and designed to engage with the first blocking element. Further, a drive mechanism may be arranged to the second blocking arrangement, wherein operation of the activator causes the drive mechanism to disengage the second blocking element with the first blocking element. In this regard, the first and the second blocking elements may be designed for form-locking of the axle when in the non-engaging position. As a type of form-locking, the first blocking element may comprise a groove extending generally transversal to the longitudinal direction of the axle and the second blocking element may comprise a plate-shaped section provided with a passage having a generally keyhole shape, wherein a narrower part of the passage fits into the groove of the axle in the engaging position and that the axle is positioned in a wider part of the passage when in the non-engaging position. A very secure locking of the axle is thus obtained by this form-locking design.

The blocking arrangement may comprise a blocking sledge provided with the second blocking element, that the blocking sledge may be arranged slidable between the engaging position and the non-engaging position, with a linkage between the blocking sledge and the activator and force elements acting on said blocking sledge for biasing it in the engaging position.

As a further security measure, the blocking arrangement may further comprise a blocker operatively arranged and designed to releasably lock the blocking arrangement in the engaging position. The blocker may be connected to the blocking sledge and being arranged slidable in directions generally transversal to the sliding direction of the blocking sledge, between a blocking position and a release position. Thus, the blocking sledge is securely blocked and prevented from manipulation.

The blocking arrangement may further comprise a blocking plate operably arranged in contact with the linkage and the blocking sledge and being slidable generally in the same direction as the blocking sledge and wherein the blocking plate is arranged to move the blocker between the blocking position and the release position when moved. The blocker may comprise a pin, which pin may cooperate with a groove of the blocking plate, which groove has a direction inclined in relation to the sliding direction of the blocking plate and the blocking sledge. In this regard, the linkage may be connected to the blocking sledge and the blocking plate such that a first movement, when the blocking arrangement is in the engaging position, causes the blocker to be moved out of the blocking position and a subsequent second movement causes the blocking sledge to be moved out of engagement with the axle. The axle may be accessible from outside the blocking device and is provided with an operating element, and wherein a force element is arranged to the axle for biasing it into the non-engaging position. The activator may comprise a code unit requiring unique code for the activation. Thus, the blocking device may not be operated unless a unique code is provided by an authorised user. For example, the code unit may be at least one key lock. As an alternative, or in addition, the code unit may be a code lock. As a further alternative the code unit may comprise an electric actuator and communication module for wireless communication.

A blocking device <NUM> shown in the drawings comprises a housing, <FIG>. In the embodiment shown the housing comprises a back or door plate <NUM> designed to be attached to a suitable surface such as the outer surface of a door, which door may be a cargo door for a transport container for instance. It is however to be understood that the blocking device may be used in numerous other applications for preventing access through a door. The back plate <NUM> is provided with a passage <NUM>, <FIG>. The back plate <NUM> is arranged with inwardly directed protrusions <NUM> positioned on opposite sides of the passage <NUM>, the function of which will be explained below. The housing further comprises a front part or cover <NUM>. The housing of the blocking device <NUM> contains an activator <NUM>, <FIG> and <FIG>, that in the embodiment shown is in the form of a code lock of the type generally available on the market. As an example, a mechanical code lock is pictured, but any traditional mechanical or electronic lock can be used. The code lock <NUM> is bolted to a base plate <NUM>, which in turn is bolted to a door or the like, preferably with bolts from the inside of the door going through the back plate <NUM>. The code lock <NUM> is provided with a handle <NUM> and a keypad <NUM>, wherein the interior of the code lock is arranged with a mechanism that blocks movement of the handle <NUM> until a correct sequence of keys are entered with the keypad <NUM>. The front cover <NUM> of the housing is in that regard arranged with openings for the handle and the keypad but is covering and protecting the rest of the code lock as seen in <FIG>. The code lock <NUM> is further arranged with an actuating pin <NUM>, <FIG> and <FIG>, extending through a passage of the base plate <NUM>, which actuating pin <NUM> is operably connected to the handle <NUM> of the code lock.

The device further comprises an engagement member in the form of a through-going axle <NUM>, <FIG>, extending through an opening in the front cover <NUM>. The axle <NUM> is preferably provided with a handle <NUM>, the function of which will be explained below. The axle <NUM> extends through a first end wall <NUM> of a generally tubular protective hub <NUM>, <FIG>. The axle <NUM> is journaled in a bushing <NUM> or slide bearing. The bushing <NUM> is positioned in a seat <NUM> of a second end wall <NUM> at the opposite side of the hub <NUM>. The hub <NUM> in turn is attached to the base plate <NUM> by a bracket <NUM> that fits into a recess <NUM> on the back side of the base plate <NUM>, <FIG>. Bolts (not shown) are threaded into threaded holes <NUM> in the hub <NUM> and clamp the hub <NUM> and the bracket <NUM> to the base plate <NUM>. In this regard, the base plate <NUM> is arranged with a passage <NUM>, <FIG> and <FIG>, through which the axle <NUM> extends.

The axle <NUM> is provided with an annular ledge <NUM> that when the blocking device <NUM> is assembled is positioned inside the hub <NUM> and is pushed against an inner surface of the first end wall <NUM> by a compression spring <NUM> having one end acting on the annular ledge <NUM>. The other end of the compression spring <NUM> is in contact with the bushing <NUM>. The arrangement enables a movement of the handle <NUM> and the axle <NUM> towards the door against the force of the compression spring <NUM>, as will be described below. In that regard, the end of the axle <NUM> is provided with a seat <NUM> at its inner end, <FIG>, which seat <NUM> is designed to fit together and act with a shaft <NUM>, <FIG>, which shaft <NUM> is an actuating part of a locking arrangement for locking the door or the like to which the blocking device <NUM> is attached. Further, the axle <NUM> is provided with an annular groove <NUM>, forming a first blocking element. The end of the axle <NUM> is also arranged with planar surfaces <NUM> of removed material.

The blocking device <NUM> is further arranged with a blocking arrangement <NUM>. The blocking arrangement <NUM> comprises a generally circular torque plate <NUM>, <FIG>, being a part of a drive mechanism that is arranged to be rotationally seated in a circular recess <NUM>, <FIG>, on the back side of the base plate <NUM>. The torque plate <NUM> is retained in the recess <NUM> by a bracket <NUM> attached to the base plate <NUM>, <FIG>. The circular recess <NUM> is arranged with a central passage <NUM> through which the actuating pin <NUM> of the code lock <NUM> extends. The inner end of the actuating pin <NUM> is arranged with a key <NUM> at its inner end, generally rectangular in the embodiment shown, which key fits <NUM> into a seat <NUM> with corresponding shape in the torque plate <NUM>, enabling rotation of the torque plate <NUM> when the handle <NUM> of the code lock <NUM> is operated.

A generally elongated torque arm <NUM>, also being a part of a drive mechanism, is pivotally journaled to the torque plate <NUM> via a first shaft <NUM> at one end thereof, <FIG>. The other end of the torque arm <NUM> is arranged with a second shaft <NUM>. The second shaft <NUM> is arranged to fit into an elongated groove <NUM> arranged at a first end of a blocking sledge <NUM>. The blocking sledge <NUM> is designed with a generally rectangular plate-shaped section <NUM> and is placed in a recess <NUM> of the base plate <NUM>, <FIG>. The plate-shaped section <NUM> is positioned to cover the passage <NUM> of the base plate <NUM> through which the axle <NUM> extends. In that regard, the plate-shaped section <NUM> is arranged with a keyhole shaped passage <NUM>, <FIG> and <FIG>, forming a part of a second blocking element with the blocking sledge <NUM>. The narrower part of the keyhole passage <NUM> has a width generally corresponding to the diameter of the annular groove <NUM> of the axle <NUM>, while the wider part of the keyhole passage <NUM> has a width larger than the general diameter of the axle <NUM>.

The blocking sledge <NUM> is further arranged with a first seat <NUM> extending in the longitudinal direction of the blocking sledge <NUM>, <FIG>. A generally plate-shape blocking plate <NUM> is designed to fit into the first seat <NUM> and to be movable in the longitudinal direction of the blocking sledge <NUM>. The blocking plate <NUM> is arranged with a passage <NUM> in which the second shaft <NUM> of the torque arm <NUM> fits, <FIG>. The blocking plate <NUM> is further arranged with an elongated groove <NUM> being inclined at an angle in relation to the longitudinal direction of the blocking sledge <NUM>. A second seat <NUM> is provided in the blocking sledge <NUM>, extending transversal to the longitudinal direction of the blocking sledge <NUM>. A generally rectangular elongated blocker <NUM> is designed to fit into the second seat <NUM> and to be moved in the transversal direction. The blocker <NUM> is arranged with a pin <NUM> that fits into the elongated inclined groove <NUM> of the blocking plate <NUM>. The blocker <NUM> is further arranged to interact with a stop ledge <NUM> provided in the base plate <NUM>, <FIG> and <FIG>, as will be described.

The blocking sledge <NUM> is moreover arranged with two stop ledges <NUM> at an upper area thereof, which stop ledges <NUM> extend transversal to the longitudinal direction on opposite sides of the blocking sledge <NUM>. The stop ledges <NUM> are designed to interact with stop surfaces <NUM> provided in the base plate <NUM>, <FIG>. The stop ledges <NUM> are further provided with through-going guide passages <NUM> extending in the longitudinal direction of the blocking sledge <NUM>. Guide pins <NUM> are provided in the guide passages <NUM>, which guide pins <NUM> are attached to side walls of the recess <NUM> of the base plate <NUM>, <FIG>. Compression springs <NUM> are arranged surrounding the guide pins <NUM>, wherein a first end of the compression springs <NUM> is in contact with the stop ledges <NUM> of the blocking sledge <NUM> and a second end of the compression springs is in contact with a side wall of the recess <NUM> of the base plate <NUM> such that the blocking sledge <NUM> is biased in the direction of the axle <NUM>.

The base plate <NUM> is further preferably arranged with a drainage <NUM>, <FIG>, in order to prevent moisture or water that might enter the blocking device <NUM> from freezing if the surrounding temperature falls below zero degrees centigrade, which could endanger the function of the blocking device <NUM>. The drainage <NUM> is arranged as a groove extending from the recess <NUM> for the blocking sledge <NUM> to an opening <NUM> at the lower end of the blocking device <NUM>. The groove <NUM> may preferably have such a shape and extension that it is very difficult to enter an object into the opening <NUM> of the drainage for manipulating the blocking arrangement <NUM>.

The blocking device <NUM> is intended to function as follows. The blocking device <NUM> is bolted to door or the like part arranged and intended to close an opening of a compartment, see for example <FIG>. The door is in this regard arranged with a locking system arranged for locking the door in the closed position by engaging with fixed structures surrounding the door. The locking system may in this regard comprise a number of different components like locking bolts that are movable between a locking position and a release position. The locking system may comprise one or several locking bolts that in the latter case may extend in different directions, such as for example espagniolette-type locking bolts. It is however to be understood that the present invention is not in any way limited to the type of locking system.

The blocking device <NUM> is bolted to a door or the like such that the passage <NUM> of the back plate <NUM> is placed in relation to an actuation shaft or axle <NUM> of the locking system is aligned with the longitudinal direction of the axle <NUM> of the blocking device <NUM>, <FIG>. In the initial inactivated position, the axle <NUM> is in its retracted position by the compression spring <NUM> that pushes it the outward direction. In this position of the axle <NUM>, the annular groove <NUM> is in the same plane as the plate-shaped section <NUM> of the blocking sledge <NUM>. Further, the blocking sledge <NUM> is in its forwardmost position whereby the narrow section of the keyhole <NUM> has been pushed into the annular groove <NUM> of the axle <NUM> by the compression springs <NUM> as seen in <FIG> and <FIG>. Further, the blocking plate <NUM> is in its forwardmost position whereby the pin <NUM> of the blocker <NUM> is in the rearmost position in the inclined groove <NUM> of the blocking plate <NUM>.

This has caused the blocker <NUM> to be moved in the transversal direction whereby it abuts the stop ledge <NUM> of the blocking sledge recess <NUM>, <FIG> and <FIG>. Thus, in the initial inactivated position of the blocking device <NUM>, the axle <NUM> is blocked in the axial position by the blocking sledge <NUM>, and the blocking sledge <NUM> is in turn blocked from movement by the blocker <NUM>. In this position, the front end of the axle <NUM> is not in contact with any component of the locking system of the door as seen in <FIG>, and any manipulation of the handle <NUM> will only result in rotation of the axle <NUM>. Further, the handle <NUM> of the code lock <NUM> is blocked by its locking mechanism and cannot be turned. However, even if substantial force was to be applied to the handle <NUM> of the code lock <NUM> in order to turn its actuating pin <NUM>, the torque plate <NUM> cannot be turned due to the linkage by the torque arm <NUM> with the blocked blocking sledge <NUM>. Such an attempt would probably only lead to that the actuating <NUM> pin of the code lock <NUM> is broken off due to its relatively small dimensions.

In order to activate the blocking arrangement <NUM>, a user has to enter the correct pin code on the keypad <NUM>. This will unlock the locking mechanism of the code lock <NUM>. It is then possible to turn the handle <NUM> of the code lock <NUM>. This will in turn cause the torque plate <NUM> to rotate due to the connection with the actuating pin <NUM>. Turning of the torque plate <NUM> will cause the torque arm <NUM> to be pulled in the rearward direction. Due to the second shaft <NUM> of the torque arm <NUM> being connected to the blocking plate <NUM>, the blocking plate <NUM> will also move in the rearward direction. This in turn will cause the pin <NUM> of the blocker <NUM> to move in the inclined groove <NUM> of the blocking plate <NUM>, causing the blocker <NUM> to be moved in the transversal direction and out of engagement with the stop ledge <NUM> of the base plate <NUM> as seen in <FIG>. During this part of the movement the blocking sledge <NUM> will not move due to that the second shaft <NUM> of the torque arm <NUM> is moving in the elongated groove <NUM> of the blocking sledge <NUM>.

Continued turning of the torque plate <NUM> will now cause the blocking sledge <NUM> to move rearwardly, <FIG>, against the force of the compression springs <NUM> because the second shaft <NUM> of the torque arm <NUM> has reached the rear end of the elongated groove <NUM> of the blocking sledge <NUM>. The narrow section of the keyhole <NUM> of the blocking sledge <NUM> is now moved out of engagement with the annular groove <NUM> of the axle <NUM> until the axle <NUM> is positioned in the wider section of the keyhole <NUM>, whereby the blocking arrangement <NUM> has released the axle <NUM>, <FIG> and <FIG>. The axle <NUM> is now free to be pushed towards the door and extend out of the passage <NUM> of the blocking device <NUM> by operating its handle <NUM> against the force of the compression spring <NUM>, wherein the front end of the axle <NUM> engages a corresponding component of a locking system for the door. In this extended engaged position, turning of the handle <NUM> will actuate the locking system and thereby open the door. The axle <NUM> is also orientated such in relation to the back plate <NUM> that when the axle <NUM> passes through the passage <NUM>, the planar surfaces <NUM> pass the protrusions <NUM> of the passage <NUM>, <FIG>.

When the handle <NUM> and thus the axle <NUM> then are turned, the protrusions <NUM> will enter into the groove <NUM> of the axle <NUM> and thereby hold the axle in the engaged axial position against the force of the compression spring <NUM>, <FIG>. This is important since both hands of a user may have to be used for opening the doors to the compartment. Especially doors that are used for fridge compartments require considerable force to pull open, both due to the thick and sturdy insulation seals surrounding the doors but also that dese doors may be jammed by ice for example.

When the door is to be locked, the handle <NUM> and thus the axle <NUM> are again turned. Turning of the handle <NUM> in the opposite direction will cause the locking system to lock the door. After that, release of the handle <NUM> will cause it and the axle <NUM> to be moved back to their initial retracted position by the compression spring <NUM>, whereby the planar surfaces <NUM> of the axle <NUM> pass the protrusions <NUM> of the passage <NUM>. The handle <NUM> of the code lock <NUM> is also turned to its initial position, which turning will cause the torque plate <NUM> to rotate and thereby push the torque arm <NUM> in the forward direction. The compression springs <NUM> acting on the blocking sledge <NUM> will in turn cause the blocking sledge <NUM> to be moved in the forward direction whereby the narrower section of the keyhole <NUM> will enter and engage with the annular groove <NUM> of the axle <NUM>, again locking it from axial movement. At the same time the blocking plate <NUM> will be moved such that the pin <NUM> of the blocker <NUM> is moved in the inclined groove <NUM>, causing the blocker <NUM> to be moved transversally into blocking engagement with the stop ledge <NUM> of the base plate <NUM>.

Even though the embodiment shown utilizes a code lock, it is to be understood that other types of locks may be used for locking the blocking arrangement from being operated, such as for instance a key lock. In this respect, it is also possible to have a two-part authentication for unlocking the blocking arrangement. For instance, both a code lock and a key lock may be arranged in the blocking device, wherein, for example, a driver has a key for the key lock but does not have the code for the code lock. Instead the code may be known only to an entrusted person at distribution site or the like, in order to minimize the risk that the blocking device may be manipulated and/or operated at an unauthorised place by for instance the driver. It is also possible to include electronically operated locking components in the blocking device that are capable of wireless communication with authorised communication devices and only when a correct code or signal is transmitted from the communication device to the blocking device, then the blocking arrangement may be operated.

In this regard, the torque plate <NUM> may be rotated by electrically driven actuators such as a stepper motor or a linear actuator. To this end, a suitable power source is arranged to provide the actuators with power to operate them. In order to activate the actuators, suitable communication devices may be utilised that preferably are provided with authorisation elements so that only dedicated communication devices may operate the actuators.

Further, the first and the second blocking elements may have alternative designs that provide form-locking functions. For instance, the axle <NUM> may be provided with a transversal hole or passage and the blocking sledge <NUM> may be provided with a pin or shaft extending in the sliding direction wherein the pin in the blocking position is positioned inside the passage and wherein the pin is moved out of the passage in the release position.

The present invention provides a locking arrangement <NUM>, <FIG>, for a door or the like element arranged for opening and closing passages to a compartment such as cargo containers, truck containers etc. containing cargo that is shipped between destinations. Of particular interest is fridge containers having doors that require considerable force to pull open, both due to the thick and sturdy insulation seals surrounding the doors but also that dese doors may be jammed by ice for example.

<FIG> show a door provided with a blocking device <NUM> according to above arranged on the outside and a locking arrangement <NUM> on the inside of the door. As seen in <FIG>, the locking arrangement <NUM> is recessed in the door in order to have a smooth planar surface. This is important in particular with trailer doors that are swung <NUM> degrees when opened and are more or less planar with the sides of the trailer. When the trailer is backed up to a loading dock, it is important that no parts protrude from the doors, which otherwise could lead to breaking of parts if the space of the loading dock between parked vehicles is limited and/or narrow and the vehicles contact each other.

The locking arrangement <NUM> comprises a housing <NUM>, <FIG>, to be inserted into a recess of a door and with flanges <NUM> to bolt the housing <NUM> to the door sides surrounding the recess. The locking arrangement is further provided with a cover plate <NUM> having an opening <NUM> for manual handling of the locking arrangement <NUM> from inside the compartment, <FIG>. The locking arrangement <NUM> further comprises a base plate <NUM>. To the base plate <NUM> a locking mechanism <NUM> is arranged, <FIG>. The locking mechanism comprises a locking bolt <NUM> arranged slidable in the housing and protruding with an end section <NUM> out of the lower edge of the door. The end section of the locking bolt <NUM> is designed to engage with a recess, seat, ledge or the like fixed structure arranged on a fixed structure of the compartment, such as a door frame or the floor of the compartment. In the embodiment shown the end of the locking bolt is arranged with an inclined surface <NUM>, enabling a movement from an extended position to a retracted position when the locking bolt during a closing action hits the fixed structure with its inclined surface. It is however to be understood that the locking bolt may have a more planar or convex end surface. The end section <NUM> is also arranged with a generally tubular element <NUM> surrounding the locking bolt <NUM>, which element is arranged to prevent attempts to saw or cut off the locking bolt in order to get access to the interior of the compartment. To that end, the element <NUM> may be provided with plates of very hard carbide material around its circumference that is very difficult to cut through. Further, the element <NUM> may be rotationally journalled on the locking bolt, causing it to rotate if for example an angle grinder is used, making it even harder to cut off the locking bolt.

The locking bolt <NUM> is provided with an elongated shaft or spindle <NUM> which is guided by two bearing blocks <NUM> attached to the base plate110. The upper end of the shaft <NUM> is arranged with a pulling knob <NUM> which is accessible via the opening <NUM>. Each bearing block <NUM> is arranged with a generally cylindrical passage <NUM>, <FIG>. Each bearing block <NUM> comprises a generally tubular slide bearing <NUM> through which the elongated shaft <NUM> of the locking bolt passes and is journalled. The slide bearing <NUM> is placed in a generally tubular bearing housing <NUM> and the unit is retained in the bearing block124 by an end plate <NUM> with a central passage <NUM> for the shaft at one end and a circlip <NUM> in a groove <NUM> in the cylindrical passage <NUM> of the bearing block <NUM> at the opposite end. The diameter of the cylindrical passage <NUM> of the bearing block <NUM> and the diameter of the bearing housing <NUM> are chosen such that there is a gap or play <NUM> between the bearing block <NUM> and the bearing housing <NUM>, enabling movement in the transversal direction of the locking bolt. This is an advantage if the door for some reason is not completely aligned in relation to the frame and therefore the locking bolt is not completely aligned with the locking recess, which could provide difficulties during a locking action. With the "floating" design of the locking bolt being movable transversally, any misalignment would be handled.

The locking mechanism <NUM> further comprises a transmission that incorporates an attachment block <NUM> that comprises a central passage through which the shaft <NUM> of the locking bolt passes. The attachment block <NUM> is provided with a locking element such as a lock screw (not shown) with which the attachment block <NUM> may be attached to the shaft <NUM> at a suitable point along its length. A compression spring <NUM> is provided between an upper end of the attachment block <NUM> and the end plate <NUM> of the upper bearing block <NUM>, where the compression spring <NUM> surrounds the shaft <NUM>. The attachment block <NUM> is further arranged with a second roller bearing <NUM> journalled on a shaft of the attachment block <NUM>. The second roller bearing <NUM> is arranged to fit into an elongated groove <NUM> of an elongated pressure arm <NUM> of the transmission. At one end of the pressure arm <NUM> a third roller bearing <NUM> is rotationally journalled. The third roller bearing <NUM> is arranged to be in contact with a track <NUM> provided in a ledge <NUM>, in turn attached to the back plate. The track <NUM> is designed with two end ledges <NUM> between which the third roller bearing <NUM> may move as will be described.

The opposite end of the pressure arm <NUM> is pivotally attached to a generally elongated lever <NUM> of the transmission at a point along its extension. The lever <NUM> is in turn pivotally attached to the base plate <NUM> at an upper end of the lever <NUM>. The locking mechanism is further arranged with an actuator <NUM> rotatably attached to the base plate <NUM> in a through-going passage. The actuator <NUM> comprises a generally cylindrical hub <NUM> extending into the passage. To the hub <NUM> an arm <NUM> is attached, which arm <NUM> is arranged with a key positioned in the centre of the hub <NUM>, which key is arranged to interact with a generally rectangular shaft <NUM>, <FIG>, which shaft <NUM> in turn is arranged to interact with the axle <NUM> of the blocking device <NUM>. The outer free end of the arm <NUM> is arranged with a first roller bearing <NUM> which is arranged to be in contact with an outer side surface of the lever <NUM> as seen in <FIG>.

The locking arrangement <NUM> is intended to function as follows. When the handle of the blocking device is operated as described above and turned clockwise as seen from outside the door, the arm <NUM> is also turned. Since the first roller bearing <NUM> is in contact with the lever <NUM>, the turning of the arm <NUM> will cause the lever <NUM> to pivot towards the locking bolt <NUM>, <FIG>. In turn, since the pressure arm <NUM> is pivotally attached to the lever <NUM>, it will also be moved and its third roller bearing <NUM> will follow the track <NUM>, pivoting the pressure arm <NUM> upwards. Since the pressure arm <NUM> is in contact with the attachment block <NUM> via the second roller bearing <NUM> following the elongated groove of the pressure arm <NUM>, the attachment block <NUM> and thus the locking bolt <NUM> to which it is attached will also move upwards against the force of the compression spring, <FIG>, whereby the end of the locking bolt will be moved out of engagement with the locking recess. The door may now be opened. A holding element may be provided for holding the locking bolt in the retracted position.

When the handle of the blocking device <NUM> is moved back to its initial position, the arm <NUM> is also moved back to its initial position and so are the rest of the components of the locking mechanism <NUM>. The locking bolt <NUM> is also returned to its extended position by the force of the compression spring <NUM> acting on the attachment block <NUM>.

<FIG> show a variant of the locking arrangement <NUM>. The same components have the same reference numerals as the previous variant. This variant is provided with a return mechanism for the locking bolt. It comprises an elongated return shaft <NUM> arranged slidable in a direction generally transversal to the direction of movement of the locking bolt <NUM>. The return shaft <NUM> is journalled in a bushing <NUM> that is attached to a side edge of a door to which the locking device is attached and preferably to the side edge that is provided with hinges. A compression spring <NUM> is arranged in the bushing <NUM> for biasing the return shaft <NUM> in the extended position, <FIG>. In the initial position with the door closed, the return shaft is retracted inside the bushing and thus the side edge of the door as seen in <FIG>. The inner end of the return shaft <NUM> is pivotally attached to one arm of a pusher <NUM>. The pusher <NUM> is provided with a fourth roller bearing <NUM>. The roller fourth bearing <NUM> is arranged to roll along an upper guide <NUM> and a lower guide <NUM> attached to the base plate and arranged parallel to each other. The upper guide <NUM> is provided with a stop ledge <NUM> for preventing movement of the pusher in the transversal direction. The pusher is arranged with a pusher plate <NUM> that is pivotally attached to the pusher. The free end of the pusher plate <NUM> is arranged with a fifth roller bearing <NUM>.

The pusher plate is further arranged with a pin <NUM> that is intended to cooperate with a groove <NUM>, <FIG>, on the inside of the stop ledge <NUM>. The lower guide <NUM> is provided with an inclined surface <NUM>, the function of which will be described below. An elongated locking arm <NUM> is further provided that is pivotally attached to the base plate via a pillar <NUM> at a point nearly in the middle of the extension of the locking arm <NUM>. In this regard, the locking arm <NUM> may be pivotally attached with a low friction bearing. At a lower end of the locking arm, a first pin <NUM> is attached and arranged to be in contact with the end of the pusher plate <NUM> and the fifth roller bearing <NUM>. An upper end of the locking arm <NUM> is provided with a second pin <NUM>, which is arranged to be in contact with the lever <NUM> as will be described. The second pin <NUM> may in this regard be provided with a roller bearing for low friction.

Further developments of the variant is that the shaft <NUM> of the locking bolt <NUM> is arranged with a locking ring <NUM>, <FIG>, whereby the attachment block <NUM> acts against the locking ring during retraction of the locking bolt. This also enables a manual retraction of the locking bolt by a person inside the compartment, by merely gripping the knob <NUM> and lifting the locking bolt. Further, a groove <NUM> is arranged in the base plate and the attachment block <NUM> is arranged with a further roller bearing on the opposite side of the second roller bearing <NUM>, running in the groove <NUM>, which provides an increased guide for the attachment block <NUM> during its movement, preventing any twisting of the attachment block <NUM> around the shaft <NUM> since it now doesn't have to be fixedly attached to the shaft <NUM>.

The variant is intended to function as follows. In the initial locked position, the locking bolt <NUM> is extended and the transmission is positioned as described above. The return shaft <NUM> is in a retracted position by the contact with the end of the return shaft against a fixed structure, such as a door frame. The pusher plate <NUM> is resting on the inclined surface <NUM> of the lower guide <NUM> and the locking arm <NUM> is biased by a torsion spring (not shown) arranged between the locking arm <NUM> and the pillar.

When the handle of the blocking device is operated to open the door, the components of the locking arrangement are moved in the same manner as above. Further, the lever <NUM> will during the movement come in contact with the second pin <NUM> of the locking arm <NUM> and pivot it so that the lower end of the locking arm <NUM> is moved towards the pusher. This is enabled in that the pusher plate <NUM> is inclined downwards, resting on the inclined surface <NUM> of the lower guide <NUM> as seen in <FIG>. As seen in <FIG>, when the locking bolt is in the retracted position, it cannot be pulled out due to that the lever <NUM> has somewhat passed the vertical position and will together with the rest of the transmission block the locking bolt <NUM>.

When now the door is opened, the return shaft <NUM> will be moved to the extended position as seen in <FIG> by the force of the compression spring <NUM>. The movement of the return shaft <NUM> will further cause the pusher plate <NUM> to be moved from the inclined position to a horizontal position, sliding along the guides <NUM>, <NUM>, whereby the pin <NUM> of the pusher plate <NUM> will enter the groove <NUM> of the stop ledge <NUM>.

During subsequent closing of the door, the return shaft <NUM> will come in contact with the fixed structure and will be pushed into the retracted position. This will in turn cause the pusher plate <NUM> to move towards and come in contact with the first pin <NUM> of the locking arm, <FIG>. The pusher plate <NUM> is guided by its pin <NUM> through an extension of the groove <NUM>, <NUM>', as seen in <FIG>. The pusher plate is further secured in this position by a spring-loaded ball <NUM> placed in the lower guide <NUM>, seen in <FIG>. Further movement will cause the locking arm <NUM> to pivot, whereby its second pin <NUM> will act on the lever <NUM> and pivot it towards its initial position. Once the lever <NUM> has passed its vertical position, the transmission is no longer locked and the force of the compression spring <NUM> will urge the locking bolt back to its extended, locking, position and all the components will return to their initial positions. The locking arm <NUM> will also return to its initial position by the torque spring and leave the contact with the fifth roller bearing <NUM> of the pusher plate <NUM>. The pin <NUM> of the pusher plate <NUM> has now left the groove <NUM>' and the pusher plate <NUM> is returned to its inclined position against the inclined surface <NUM>.

<FIG> show another variant of the return mechanism <NUM>. The same components have the same reference numerals as the previous variant. This variant is provided with another variant of a return mechanism for the locking bolt. It comprises an elongated return shaft <NUM> arranged slidable in a direction generally parallel to the direction of movement of the locking bolt <NUM>. The return shaft is arranged with an inclined end surface <NUM> intended to come in contact with a fixed structure of the compartment when the door is closed. The return shaft is arranged with an overload mechanism comprising an end bolt <NUM> having the inclined end surface <NUM>, <FIG>. The end bolt <NUM> is arranged with a threaded hole in which a threaded section of a piston <NUM> is connected. The upper end of the piston <NUM> is placed in a cylinder <NUM>. A spring <NUM> is arranged surrounding the piston and is pretensioned between a rear end surface of the end bolt <NUM> and a front surface of the cylinder <NUM>. The cylinder-piston arrangement is placed in a sleeve <NUM>, which sleeve <NUM> is arranged with an upper contact part <NUM> to be in contact with an upper part <NUM>' of the return shaft. The return shaft <NUM> may extend into the locking arrangement, but may also be divided so that there is a gap between the lower part and the upper part of the return shaft <NUM>. An advantage with the gap is that the travel of the return shaft <NUM> may be adjusted to the specific door arrangement and the distance between the lower edge of the door and the fixed structure surrounding the door, such as a door frame or the floor of the compartment.

The upper part <NUM>' of the return shaft is slidably journalled in a bearing block <NUM>. The bearing block <NUM> may be attached to an assembly block <NUM> which in turn is attached to the base plate <NUM>. Further, a nut <NUM> may be threaded onto the upper part of the return shaft <NUM> and a compression spring <NUM> is arranged between the nut <NUM> and a downward surface of the bearing block <NUM> for urging the upper part <NUM>' of the return shaft <NUM> in the downward direction. The nut <NUM> enables adjustment of the tension and thus the force of the compression spring <NUM>. The upper end of the return shaft is attached to a pusher <NUM>. The upper part of the pusher <NUM> is arranged with a through-hole <NUM>, which is cooperating with a pin <NUM>, extending generally transversal to the direction of the return shaft <NUM> and thus the sliding direction of the pusher <NUM>. The pin <NUM> is arranged in an elongated hole <NUM> in an assembly block <NUM> and is provided with an enlargement <NUM> fitting in a recess <NUM> surrounding the elongated hole <NUM> on the backside of the assembly block <NUM>, <FIG>, enabling a sliding action of the pin <NUM>.

Further, the pin <NUM> extends through a hole in a follower <NUM> so that the follower <NUM> and the pusher <NUM> are slidably connected. However, the arrangement provides a certain turning of the follower <NUM> as will be described. On the backside of the follower <NUM>, a first roller bearing <NUM> is attached. The first roller bearing <NUM> is arranged to fit into a recess <NUM> in the assembly block <NUM> arranged above the elongated hole <NUM>. The side surfaces of the recess <NUM> are such that the left side, as seen in <FIG> extends in a generally straight line with the elongated hole <NUM>. The side surface transforms into a curved top surface wider than the elongated hole so that the right wall extends back with an inclination in relation to the direction of the elongated hole <NUM>. The function of this design will be explained below. The follower <NUM> with the first roller bearing <NUM> is further biased towards the left side surface of the recess <NUM> by a leaf spring <NUM> pressing on the right side surface of the follower <NUM> as seen in <FIG>.

Further, a generally T-shaped pulling arm <NUM> is pivotally attached to the assembly block <NUM> via a shaft <NUM> at the left upper part as seen in <FIG>. The right upper part of the pulling arm <NUM> is pivotally connected to the follower <NUM> via a pin <NUM> fitting in a recess <NUM> of the follower <NUM>. The lower end of the pulling arm <NUM> is in turn pivotally connected to one end of an elongated tension rod <NUM> via a shaft <NUM>. The other end of the tension rod <NUM> is pivotally attached to one end of an elongated actuator arm <NUM> via a shaft <NUM>. The actuator arm <NUM> is further pivotally journalled on a shaft <NUM> attached to the base plate <NUM> about midway along the extension of the actuator arm <NUM>. A compression spring <NUM> is attached with one end to the actuator arm <NUM> at a location between the pivot point of the actuator arm <NUM> and the attachment point of the pulling arm <NUM>. The other end of the compression spring <NUM> is attached to a point on the base plate <NUM>. An inwardly extending pin <NUM> is attached to the other end of the actuator arm <NUM>, on which pin a roller bearing <NUM> is journalled. The roller bearing is arranged to be in contact with the lever <NUM> as will be explained below.

The arrangement is intended to function as follows. When in an initial position as seen in <FIG>, for instance when the door is open, the locking bolt <NUM> is retracted. This is done in that a handle or the like is turned on the outside whereby the hub <NUM> with its arm <NUM> has been turned to a vertical downward position. The fourth roller bearing <NUM> of the actuator arm <NUM> then acts on the lever <NUM>, which will pivot towards the locking bolt <NUM>. In turn, since the pressure arm <NUM> is pivotally attached to the lever <NUM>, it will also be moved and its third roller bearing <NUM> will follow the track <NUM>, pivoting the pressure arm <NUM> upwards. Since the pressure arm <NUM> is in contact with the attachment block <NUM> via the second roller bearing <NUM> following the elongated groove of the pressure arm <NUM>, the attachment block <NUM> and thus the locking bolt <NUM> to which it is attached will also move upwards against the force of the compression spring <NUM>, whereby the end of the locking bolt <NUM> will be moved to the retracted position. The arrangement is held in this position because the lever <NUM> has passed the vertical orientation and is somewhat tilted towards the locking bolt.

The return shaft <NUM> is in its extended position by the compression spring <NUM> and the return mechanism is unaffected.

When the door is closed the inclined end surface <NUM> of the return shaft <NUM> will strike against a fixed structure surrounding the door such as a door frame or the floor of the compartment. The inclination of the end surface <NUM> will cause the return shaft <NUM> to move upwards against the force of the compression spring <NUM>. If the door and the door frame for some reason are misaligned so that the return shaft may be pushed too far upwards, risking damage to the mechanism, the overload mechanism will come in action, whereby the end bolt <NUM> will move upwards in the sleeve <NUM>, thereby compressing the spring of the cylinder-piston arrangement, thereby taking up any excessive movement of the return shaft <NUM>.

Further movement upwards of the return shaft <NUM> will cause the pusher <NUM> to move upwards and due to the connection with the follower <NUM>, the latter will also move upwards. The first roller bearing <NUM> of the follower <NUM> will run in the recess <NUM> of the assembly block <NUM> and due to the shape of the recess <NUM>, the recess will tilt the follower <NUM> to the right against the force of the leaf spring <NUM>. The tilting of the follower <NUM> will cause the T-shaped pulling arm <NUM> to pivot so that the lower part of the pulling arm <NUM> is moved to the right, see <FIG>. Due to the linkage with the actuator arm <NUM> via the tension rod <NUM>, the upper part of the actuator arm <NUM> will pivot to the left, in turn pushing the lever <NUM> to the left by the contact with the bearing <NUM>.

Once the lever <NUM> has passed its vertical position, the transmission is no longer locked and the force of the compression spring <NUM> will urge the locking bolt <NUM> to its extended, locking, position and all the components of the transmission will return to their initial positions as shown in <FIG>. However, the return shaft <NUM> will still be in its biased position, and thus the other components of the return mechanism are not moved, until the locking assembly is operated by turning a handle on the outside such that the locking bolt is again retracted as described above and the door is opened. This will cause the return shaft <NUM> to be moved out of contact with the surface on which it has been resting on, whereby the return shaft <NUM> is moved downward by the compression spring <NUM>. This in turn will cause the follower <NUM> to return to its initial position by the leaf spring <NUM> and the rest of the components of the return mechanism are moved to their initial positions as described above.

If for some reason the return mechanism is not capable of activating the locking process as described above, the locking may be performed manually by operating the opening device manually. For this purpose a return arm <NUM> is pivotally attached to the arm <NUM> of the actuator <NUM>, <FIG>. The return arm <NUM> is further arranged with an elongated groove <NUM>, in which a bolt <NUM> is placed. The bolt <NUM> is attached to a lower area of the lever <NUM>. The turning of the actuator <NUM> will cause the hub <NUM> and the arm <NUM> to rotate and due to the connection between the arm <NUM> and the lever <NUM> with the return arm <NUM>, the lever <NUM> will be turned when the bolt <NUM> has reached the end of the elongated groove <NUM> of the return arm <NUM>, until the lever <NUM> passes its vertical position and the locking mechanism will move the locking bolt <NUM> to its locking position as described above.

<FIG> show a further variant of a return mechanism for the locking bolt. The same components as for the previous variants have the same reference numbers. It also comprises a return shaft <NUM>. The upper part <NUM>' of the return shaft is attached to a generally plate-shaped pusher <NUM>, <FIG>. The pusher <NUM> is guided by an elongated groove <NUM> in the assembly block <NUM>. Further, a generally T-shaped pulling arm <NUM> is pivotally attached to the assembly block <NUM> via a shaft <NUM> at the left upper part. At the right upper part, a pin <NUM> is pivotally attached, extending generally in the extension of the pulling arm <NUM>. The pin <NUM> extends through a hole <NUM> in a generally plate-shaped follower <NUM>, wherein the follower is arranged generally perpendicular to the extension. The hole <NUM> is somewhat larger than the diameter of the pin <NUM>. An upper part of the pin fits into a hole <NUM> in a downward end surface of the assembly block <NUM>. The follower <NUM> is attached to the assembly plate <NUM> via pins <NUM> extending into elongated grooves <NUM> in the assembly plate <NUM> and in a holding plate <NUM> attached to the ledge <NUM>, allowing a movement of the follower <NUM> in the direction of the extension and also a slight turning around the pins <NUM> as will be described. A compression spring <NUM> is arranged surrounding the pin between a seat around the hole <NUM> in the downward end surface of the assembly block <NUM> and a side surface of the follower <NUM>. The rest of the mechanism of the variant is the same as described above and will not be described in detail.

The function of the variant is as follows. When the lower end of the return shaft <NUM> comes in contact with a fixed structure surrounding the door, it will move upwards, whereby the pusher <NUM> will move upwards in the groove of the assembly block <NUM>. The upper end of the pusher <NUM> will in turn come in contact with a downward directed surface of the follower <NUM>, where the contact point is offset in relation to the hole <NUM> of the follower <NUM> in which the pin <NUM> extends. When the follower <NUM> now is moved by the pusher <NUM>, the offset will cause the follower <NUM> to turn somewhat. Since the hole <NUM> of the follower <NUM> is somewhat larger than the pin <NUM> the turning of the follower <NUM> will cause a locking effect between the pin <NUM> and the hole <NUM>, whereby the pin <NUM> will move upwards together with the follower <NUM> against the force of the spring <NUM> with the pins <NUM> sliding in the grooves <NUM>. Since the pin <NUM> is pivotally attached to the right side of the T-shaped pulling arm <NUM>, the pulling arm <NUM> will pivot around the shaft <NUM> and in turn act on the tension rod <NUM>, <FIG>, releasing the locking bolt as described above.

When the door is opened, the return shaft <NUM> with the pusher <NUM> will move downward by the force of the return shaft spring <NUM> and the follower <NUM> will be moved back to its initial position in contact with the upper end surface of the pulling arm <NUM> by the spring <NUM> surrounding the pin. The rest of the release mechanism will now assume the initial position.

In order to increase the distance that the locking bolt can travel, the pressure arm <NUM> may be arranged with a mechanism since the pivoting movement of the pressure arm dictates the movement of the locking bolt as described above. The mechanism comprises a lifting arm <NUM> to the free end of the pressure arm <NUM>, <FIG>. The lifting arm <NUM> is provided with an elongated groove <NUM> through which a bolt <NUM> is arranged, connected to the attachment block <NUM>. Further a section of the pressure arm <NUM> above the groove <NUM> has been removed.

When the door is opened by turning an actuator from the outside, the mechanism described above will pivot the pressure arm <NUM> upwards, wherein the bearing of the attachment block will move in the groove of the pressure arm as described above while the bolt <NUM> of the attachment block moves in the groove <NUM> of the lifting arm <NUM>. Near the end of the lifting stroke, the bolt <NUM> has reached the lower end of the groove <NUM> of the lifting arm <NUM> and further movement of the pressure arm will provide a further raising of the locking bolt as seen in <FIG>.

In order to prevent manipulation of the locking bolt manually, especially trying to move it from a locking position, a blocking arrangement may be used, <FIG> and <FIG>. A cylindrical bushing <NUM> is fixedly attached to a plate <NUM> that in turn is attached to a downward surface of a door or the like openable component. The locking bolt <NUM> is provided with a cylindrical sheath <NUM> that is movable along the locking bolt, wherein the lower part of the locking bolt <NUM> may extend out of a lower end of the sheath <NUM>. The inner surface of the sheath <NUM> is arranged with protrusions <NUM> at its lower end, providing a distance between the locking bolt and the sheath, and has an end wall <NUM> at its upper end with a central hole <NUM> through which the shaft <NUM> of the locking bolt extends. The sheath <NUM> has a diameter that is just smaller than the inner diameter of the bushing <NUM>, whereby the bushing <NUM> acts as a slide bearing for the sheath <NUM>. A circular locking plate <NUM> is arranged inside the sheath <NUM> between its end wall <NUM> and an upper surface of the locking bolt. The locking plate <NUM> is arranged with a central hole <NUM> through which the shaft <NUM> extends, wherein the diameter of the hole <NUM> is somewhat larger than the diameter of the shaft <NUM>. The locking plate <NUM> is further arranged with a protrusion <NUM> that extends into a slot <NUM> in the sheath <NUM> wherein the outer end surface of the protrusion <NUM> generally coincides with the outer surface of the sheath <NUM>. Further, an inwardly directed protrusion <NUM> is arranged on the inner wall of the sheath <NUM> below the locking plate <NUM> and opposite the slot <NUM> as seen in cross-section. The length of the slot <NUM> and the inwardly protrusion <NUM> limits the movement of the locking plate <NUM>.

When the locking bolt is in its extended and thus locked position and someone tries to manually raise the locking bolt upwards, the sheath <NUM> is the only part accessible and if the sheath <NUM> is pushed upwards, the inwardly directed protrusion <NUM> will push on the locking plate <NUM>. Since the contact point between the protrusion <NUM> and the locking plate <NUM> is offset to the central shaft <NUM> of the locking bolt, the locking plate <NUM> will tilt, whereby the edges of its central hole <NUM> will engage with the shaft <NUM> and lock the locking plate <NUM> to the shaft <NUM>. Further, the tilting of the locking plate <NUM> will cause its protrusion <NUM> in the slot <NUM> of the sheath <NUM> to protrude outside the surface of the sheath <NUM> and will engage with the inner surface of the fixedly attached bushing <NUM> due to the rather tight tolerances therebetween. This will then also cause a locking action, effectively preventing any upwards movement of the locking bolt, and the more force that is used on trying to lift the sheath the stronger the locking action both between the locking plate and the shaft and between the locking plate and the bushing.

Should the locking bolt be lifted in the normal way as described earlier, the shaft will pull the locking bolt upwards. The diameter of the locking bolt is such that it will pass the inwardly directed protrusion <NUM> and be move in contact with the locking plate. Since the upper end surface of the locking bolt is parallel with the locking plate <NUM>, the latter will not tilt and the whole assembly can be moved to the unlocking position through the bushing.

Claim 1:
Locking arrangement for releasably locking a door of a compartment, the locking arrangement comprising:
- a locking bolt (<NUM>) movable between an extended locking position and a retracted release position;
- an actuator (<NUM>) operably connected to an opening element, the actuator being rotatable between an initial position and an activated position;
- a transmission (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) arranged between the actuator (<NUM>) and the locking bolt (<NUM>), the transmission being arranged to move said locking bolt (<NUM>) between the extended position and the retracted position when the actuator is rotated, wherein said transmission comprises
- a lever (<NUM>) arranged pivotable and in contact with the actuator;
- a pressure arm (<NUM>) pivotally attached with one end to the lever and operably connected to said locking bolt;
- wherein rotation of the actuator causes the lever to pivot and the pressure arm to act on said locking bolt for moving said locking bolt from the extended position to the retracted position,
wherein said actuator (<NUM>) comprises an arm (<NUM>), a first roller bearing (<NUM>) journalled at a free end of said arm (<NUM>), which first roller bearing (<NUM>) is arranged in contact with and run along a surface of said lever (<NUM>),
said pressure arm (<NUM>) being arranged with an elongated groove (<NUM>), the locking bolt (<NUM>) being arranged with an attachment block attached to said locking bolt, said attachment block being arranged with a second roller bearing (<NUM>) arranged to run in said groove,
said transmission further comprising
- a support surface (<NUM>) provided with a track (<NUM>) and wherein a second end of said pressure arm is arranged to be in contact with and run in said track.