The invention relates to a locking device for gates, doors, leaves, drawers and the like, and of the kind disclosed in the preamble to claim 1.

With certain applications of plate-enclosed units for heavy current, demands are made to the effect that doors and covers must not be able to spring open, even though an arc occurs behind the door or cover, e.g. from a short-circuit, and there hereby moment¬ arily arises a high gas or air pressure from the arc, also even though means exist for leading away the gas or air pressure. Very high demands are thus made on the closing mechanism, partly with regard to its strength and partly with regard to its construction, so that it is ensured that the cover cannot be closed unless the closing element is in safe engagement with the associated retaining element or similar means in the frame or doorpost.

Also for other uses, e.g. oven doors, doors to re¬ frigerators, chemical cabinets and the like, it is of great importance that in the closing of a cover or door that its closing mechanism is in safe and solid engagement with frame or doorpost, so that the door cannot spring open under influences from inside, but can only be opened with the handle.

Known closing elements for such applications are designed in such a manner that use must be made of tools or keys in order to close a leaf, or manual use must be made of thumbscrews or the like before

the leaf can be closed.

The object of the invention is to present a locking device which is arranged in such a manner that when the leaf or the drawer is pushed in, an automatic closing and tensioning occurs during the last phase of the closing.

This is achieved by configuring the locking .device according to the invention as characterized in claim 1. When a leaf or a drawer with a locking device ac¬ cording to the invention is closed, i.e. against the frame or post with retaining element according to the invention, the energy stored up in the mechanical energy store is released and the bolt enters into firm and solid engagement with the tracks in the re¬ taining element, and can only be led out of engage¬ ment herewit by turning the handle, but e.g. not by a strong compressive force, for instance from an ex- plosion or arc in the area enclosed by the leaf. The energy store, which will usually be a steel spring, will be automatically tensioned when the leaf or the drawer is opened in the correct manner by means of the handle.

The locking device according to the invention can be configured as characterized in claim 2, whereby a secure activation of the closing of the leaf is ach¬ ieved, in that the closing is not initiated until the leaf is almost completely in place against the frame or the doorpost.

By configuring "the locking device according to the invention as characterized in claim 3 or 4, a very

simple construction is achieved which comprises very few individual parts. The locking device becomes ex¬ tremely reliable and, for the reason that it consists only of very few individual parts, can be produced with particularly reasonable costs.

The release element in the locking device according to the invention is preferably configured as char¬ acterized in claim 5, in that the release element is hereby given an additional function, namely to ensure that when the leaf is opened by means of the handle on the outside of the cabinet, one cannot avoid the spring being given sufficient tension, in that the leaf cannot be opened until the spring is tensioned and the release element is held in engagement with the edge of the opening in the lock housing.

The retaining element in the locking device is pref¬ erably configured as characterized in claim 6, in that it hereby supports the release element so that it has limited possibility of movement and cannot be ruined, not even by violent opening or closing of the leaf.

By configuring the locking device according to the invention as characterized in claim 7, the release spring will remain unaffected when the leaf is cor¬ rectly closed, so the spring is not ruined or deform¬ ed by a constant influence.

By further configuring the locking device according to the invention as characterized in claim 8, the release spring is given an additional function, ,in that it contributes towards ensuring that the stag-

gered part of the release mechanism enters into pos¬ itive engagement with the opening when the leaf is opened, because the release spring pulls and holds the release element against that part of the housing in which the opening is placed.

The locking device according to the invention is preferably configured as characterized in claim 9, in that this provides the possibility of assembling and holding the parts together in a simple and practical manner while providing a strong construc¬ tion which can enter into very solid engagement with the retaining element.

Even though the locking device according to the in¬ vention can be used in many places, it has been de¬ veloped especially for use in connection with leaves, such as covers, doors, gates, drawers etc. in plate -enclosed electrical units for heavy current, as dis- closed in claim 10. Security is hereby provided that the closing of the leaves always takes place in such a manner that they cannot spring open, even though an arc should occur behind said leaves, but they can still be opened by means of the handle for repair work and inspection, possibly without the use of tools.

The invention will now be described in more detail with reference to the drawing, in that

fig. 1 shows a smaller plate-enclosed electrical unit for heavy current,

fig. 2 shows the locking device according to the

invention, mounted on a door which is hinged on a post with a retaining element,

fig. 3 shows the locking device in fig. 2, seen in the direction III-III,

fig. 4 shows the whole of the locking element in the form of an exploded drawing covering all of the individual parts,

fig. 5 shows how the release element cooperates with the releaser, and

fig. 6 shows the same as in fig. 5, but seen from another side.

In fig. 1 is seen an example of a smaller plate-en¬ closed electrical unit for heavy current, in which the electrical bus-bar areas, circuits, components etc. are located behind the doors or covers 1, or in extractable drawers. The doors are suspended on a frame (not shown) , for example built up of posts and traverses etc. , and in the embodiment shown the leaves can be opened and closed by means of the han- dies 3 which can possibly be provided with key-locks. The handle 3 can be replaced by other means of open¬ ing, depending on the national demands in this regard in many countries, e.g. a slotted screw or a screw for a triangular key, so that the use of tools is re- quired to open a leaf or a drawer, a thumbscrew or other known means of opening. However, it will be ob¬ vious to those familiar with the art that the inven¬ tion can be used in plate-enclosed units of any size, i.e. both larger and smaller units than that shown in

fig. ^" 1 .

In fig. 2 is seen a door (leaf) 1 opposite a post or frame 2 which is made of rolled and profiled steel plate, and which is surface-treated and provided with holes, possibly threaded holes, at regular intervals. The leaf 1 is normally made of iron or steel plate with folded over sides, and which is also surface treated. On the leaf 1 is seen a housing 6,6' which. surrounds the individual parts of the locking device and which is described in more detail in connection with fig. 4 of the drawing. On the front of the leaf 1 is seen a handle 3 which is secured on a through -going axle 5 extending out from the housing..The axle 5 is turned by turning the handle 3. The actual locking bolt 4, in the form of a transverse spindle, which is also shown and described in more detail in connection with fig. 4, is arranged on the free end of the axle 5.

In fig. 3 is seen the one part 6' of the housing with axle 5 and bolt 4. The housing part 6' also comprises a multi-edgedopening 12 through which there is access for a releaser 13 arranged to be influenced by a re- lease element 11 on the retaining element 7 on the post or t≤he frame 2, see fig. 2. The retaining ele¬ ment 7 is a folded and machined, solid piece of steel plate (see also fig. 4) which comprises forwardly-ex- tending webs, each with an aperture 8 arranged for engagement with the bolt 4 by turning of the axle 5.

In fig. 4 is seen all the individual parts in the locking device which, seen from the left to the right, comprises:

A handle 3, possibly with key-lock 23, mounted on an axle which consistsofa quadrangular part 5' and a part 5 with circular cross-section, in the free end of which there is provided a transverse hole 21 for the bolt.

A two-part housing 6,6' formed by two pieces of iron plate and arranged for assembly with rivets or screws.

An energy store in the form of coil spring 15 placed on the axle 5' .

A spring retaining disk 16 with quadrangular hole corresponding to the axle 5' , and an opening 17 for securing the one end of the spring 15.

A release disk 13 with quadrangular hole correspond¬ ing to the axle 5' , and with a staggered edge 14 ar- ranged to enter into engagement with the edge of the opening 12 in the one part 6' of the two-part hous¬ ing.

A housing part 6 ¹ with opening for the axle 5 on which a circlip 22 is mounted, hereby holding the axle in position. The housing part 6' also comprises a groove 18 for securing the other end of the spring 15.

A transverse spindle 19 with two steel rollers 20 which are secured by two circlips 22. The rollers are arranged to enter into engagement with the apertures 8 in the retaining element 7 and reduce the friction so that positive locking is always achieved. The

transverse spindle 19 is arranged to pass through the hole 21 in the axle 5. The transverse spindle is turned 25-65 in relation to the vertical channel in the retaining element 7.

A retaining element 7 with two forwardly-extending webs with apertures 8 is arranged to be screwed or riveted to the post 2, which is provided with thread¬ ed holes 10. The one web of the retaining element 7 is additionally configured with a downwardly-extend¬ ing finger 9, arranged to be in engagement with the release spring 11. The retaining element also com¬ prises a ϋ-shaped spring 11 of plate material, e.g. stainless steel. The release spring 11 is secured to the post 2 together with the locking element 7, so that a free end extends forwards. The free end is shaped and bent in such a manner as to provide two parts 25 and 26, see figs. 2 and 5, which constitute a forwardly-turning hook-like part and an angularly bent area 24 which supports the hook-like part so that it cannot move sideways or forwards for reason of the finger 9 on the retaining element 7. However, the hook-like part 25, 26 can move in against the post 2 against the spring power of the release spring 11.

In fig. 5 is seen the function of the release spring 11 from the side during the closing and opening (fig. 5A and fig. 5B respectively) of a leaf with a lock- ing device according to the invention. In fig. 6 is seen the Cooperation of the release spring 11 with the release .part 13, seen in the direction towards the retaining element through the housing, see the arrow marked fig. 6 in fig. 4, in that fig. 6a shows

the position of the parts at the moment of closing, immediately before the staggered edge 14 moves free of the the opening 12, which corresponds to fig. 5A. In fig. 6C is seen the situation a moment later, i.e. when the bolt has entered into engagement with the retaining element, and it is seen that the release spring extends freely in through the opening 12, be¬ cause the outwardly-extending, staggered part follows with the turning of the axle. In fig. 6B, the parts. are seen during the opening of the leaf, correspond¬ ing to fig. 5B, and where the hook-like part 26 of the release spring 11 is "behind" the release disk 13 and draws it towards the opening 12.

The locking element according to the invention func¬ tions as follows: When the leaf 1 is closed against the post 2, the rollers 20 on the bolt 4 will be in firm engagement with the apertures 8 in the retaining element 7. In the example shown, the leaf is opened by turning the handle 3 in the anti-clock ise direc¬ tion. At the same time herewith, the axle 5, 5 ^■ is turned and the spring 15 is tensioned, and because the spring 15 presses the disks 16 and 13 against the inner side of the housing part 6' , and the release spring 11 (see figs. 5B and 6B) presses the outwardly extending, staggered part of the release disk 13 to¬ wards the opening 12, the locking edge 14 of the re¬ lease disk 13 will slip out in the hole 12 and, when the handle 3 is released, the edge 14 will rest se- curely against the edge of the hole 12 (see fig. 3) , and the spring will remain tensioned. This happens at the same time that the bolt moves free of the retain¬ ing element, so the leaf cannot be opened without the spring being tensioned.

When the leaf 1 is closed, the hook-like part 26 of the release spring 11 will press the release disk 13 into the housing so much that the edge 14 moves free of the opening 12, and the elastic force in the spring 15 will ensure that the bolt enters into.firm and positive engagement with the apertures 8, and that the bolt remains in engagement herewith. Con¬ sequently, the leaf 1 can not be closed without the locking device ensuring that the leaf is solidly se- cured against the post 2. Like the spring 15, the release spring 11 is a robust spring, e.g. of stain¬ less steel, which can tolerate strong mechanical in¬ fluences without being ruined.