Operative plate for a switch cubicle

An operative plate fitted to a wall or a door of a switch cubicle which can be moved from a parallel storage position to a folded-down working position. The operative plate is accessible from three sides in the operative position owing to its special linkage to the wall or door and control by specially articulated arms.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a work surface attached to a wall element or a 
door of a switchgear cabinet, which can be brought from a parallel stowed 
position into a flipped-down work position. 
2. Description of Prior Art 
The known work surfaces of this type are attached like leaves to a wall 
element or a door of a switchgear cabinet. Here, the lower horizontal side 
of the work surface is hinged on the wall element or the door by a hinge 
or the like. The vertical sides of the working surface are connected by 
leaf holders, known per se, with the wall element or the door. As shown in 
German Patent Reference DE 43 12 816 A1, the leaf holders have two guide 
rods, which are hingedly connected with each other, and whose free ends 
are hinged to the work surface, or respectively the wall element or the 
door. In the extended position of the two guide rods, the leaf holders 
determine the work position of the work surface, while in the stowed 
position they are pivoted on each other. In the work position of the work 
surface the leaf holders extend over at least a portion of the two sides 
of the work surface and therefore more or less hamper working on the work 
surface. 
A switchgear cabinet with a circuit diagram pocket is shown in German 
Patent Reference DE 36 38 454 A1. The circuit diagram pocket can be 
pivoted into the desk position by guide pins and a crank guide. 
German Patent Reference DE 41 21 660 A1 shows a folding table with a table 
top which can be folded out and which is pivotally and displaceably held 
in lateral frame sections with its inner end. The table top is hinged on 
pivotal strips and can be brought into a horizontal position by displacing 
and rotating its end. 
SUMMARY OF THE INVENTION 
It is one object of this invention to attach a work surface of the type 
mentioned at the outset in such a way that, after two vertical sides are 
brought into a work position above the work surface, the two vertical 
sides are free and permit unhampered work thereon. 
In accordance with this invention this object is attained because the 
horizontal side of the work surface which is on top in the stowed position 
is guided, vertically adjustable, by means of hinge bolts in insertion 
grooves fixed in the wall element or door. The lower ends of the guide 
grooves make a transition via transition sections pointing away from the 
wall element or the door into upward pointing holding receptacles for the 
hinge bolts. The vertical sides of the work surface are hingedly supported 
by means of respectively a guide rod on the wall element or on the door, 
wherein the hinge points at the work surface are arranged below the hinge 
bolts, and the hinge points at the wall element or the door are arranged 
below the holding receptacles of the guide grooves and are laid out with 
the size of the guide rods in such a way that, when the hinge bolts are 
inserted into the holding receptacles, the work surface takes up the 
desired work position with respect to the wall element or to the door. 
To place the work surface into the work position, it is grasped at the 
lower horizontal side and lifted. In the process the slide bolts slide 
downward in the guide grooves. Shortly before reaching the work position, 
the work surface is slightly moved away from the wall element or the door 
in the transition sections, guiding the hinge bolts into the holding 
receptacles of the guide grooves under its own weight and in this way is 
fixed in the work position. If the work surface is returned again into the 
stowed position parallel with the wall element or the door, the free, 
projecting side of the work surface is slightly lifted, whereupon the 
hinge bolts leave the holding receptacles of the guide grooves. By a 
slight displacement of the work surface in the direction toward the wall 
element or the door, the transition sections are overcome and the hinge 
bolts reach the vertical areas of the guide grooves. If the work surface 
is released, driven by its own weight it moves into a stowed position, 
which is reached at a time when the hinge bolts rest against the upper 
ends of the guide grooves. 
In the work position the guide rods always are located under the top of the 
work surface and no longer hamper work on it in any way. The change from 
the stowed position into the work position and vice versa can be performed 
by simple manipulation. 
If in one embodiment the hinge bolts and the hinge points are arranged on a 
bent-off edge of the work surface, wherein the edge in the parallel stowed 
position is oriented toward the wall element or the door, the work surface 
not only has a sufficient rigidity, but the edge also simplifies the 
attachment of the hinge bolts and the guide rods. In this case it is 
preferably provided that the edge extends over all four sides of the 
rectangularly-shaped work surface. 
For guiding the hinge bolts of the work surface when the position is 
changed, the guide groove, the transition section and the holding 
receptacle are introduced into a lateral leg of a fastening strip 
extending vertically with respect to the wall element or the door. Here, 
guidance can be simply achieved and improved because the hinge bolts on 
the work surface are formed by screws with screw heads which are screwed 
through the guide grooves into the edge of the work surface, wherein the 
screw head is larger in diameter than the width of the guide grooves. 
In accordance with one embodiment the fastening of the fastening strip on 
the wall element or the door is accomplished in a simple way because the 
fastening strip is formed in a U-shape and rests with its center leg 
against the wall element or the door, and that suspension brackets, with 
which the fastening strip is screwed to a reinforcement frame connected 
with the wall element or the door, are bent out of the lateral leg of the 
fastening strip facing away from the work surface. 
So that the guide rods do not hamper the setting of the work and stowed 
positions of the work surface, in one embodiment the guide rods are hinged 
to the sides, which face away from the work surface, of the lateral legs 
of the fastening strips that have the guide grooves, and the guide rods 
are hinged via spacer elements to the work surface, so that, in the stowed 
position, the guide rods lie on sides facing away from the work surface of 
the lateral legs of the fastening strips that have the guide grooves, and 
the lateral legs have recesses for receiving the spacer elements of the 
hinge points fixed in place on the work surface. 
A preferred exemplary embodiment provides, that in the work position it 
extends perpendicularly with respect to the wall element or the door. 
If the layout is such that the guide grooves have increasing distance from 
the wall element or the door in the direction toward the upper ends, so 
that in the stowed position there is space for the edge of the work 
surface, then the work surface can then come very close to the wall 
element of the door in the work position.

DESCRIPTION OF PREFERRED EMBODIMENTS 
A view of the inside of the door 10 of a switchgear cabinet is shown in 
FIG. 1, wherein only the area to which a work surface 20 is attached is 
shown. The door 10 is reinforced by an edge 11, bent toward the interior, 
which can extend over all four sides. A reinforcement frame is attached to 
the inside of the door 10, portions of the vertical legs 12 of which are 
shown. The legs 12 have fastening bores 13. A sealing element 16 is 
arranged between the edge 11 and the reinforcement frame, which seals the 
door 10 when closing the associated open side of the switchgear cabinet. 
The work surface 20, shown in the stowed position, is connected on both 
vertical sides with respectively one fastening strip 30. The fastening 
strips 30 are U-shaped, wherein the lateral leg 37 facing away from the 
work surface has bentaway suspension hooks 38. The distance between the 
two suspension hooks 38 is matched to the divisions of the fastening bores 
13 in the legs 12 of the reinforcement frame. If screws 14 are screwed 
into the assigned fastening bores 13, the unit comprising the work surface 
20, the guide rods 24 and the fastening strips 30 can be suspended from 
the screws 14 and, by tightening the fastening screws 14, the unit can be 
fastened on them. In this case the exterior dimensions of the unit are 
matched to the distance between the vertical legs 12 of the reinforcement 
frame. 
As shown in FIGS. 2 and 3, two hinge bolts 22 are inserted into the lateral 
edge 21 in the area of the upper, horizontal side of the work surface 20, 
which are designed as screws with screw heads and which are screwed into 
the edge 21. The screw head has a diameter which is greater than the width 
of the guide grooves 32 cut into the lateral leg 31 of the fastening strip 
30 facing the work surface 20. In the process, the screws are passed 
through the guide grooves 32 and screwed together with the edge 21. A 
guide rod 24 is provided on each side of the work surface 20, which is 
hingedly attached to the work surface 20 on the one side at the hinge 
point 23, and on the other side at the hinge point 25 of the fastening 
strip 30. Here, the hinge point 25 is placed on the lateral leg 31 facing 
away from the work surface 20. The hinge point 23 on the work surface 20 
includes a spacer element, so that in the stowed position the guide rod 24 
also rests on the side of the lateral leg 31 facing away from the work 
surface 20. Here the lateral leg 31 has a recess 35, open toward the 
front, for receiving the spacer element of the hinge point 23. 
It should be noted that on the left side of the work surface 20, which is 
not shown in detail, the fastening strip 30 is embodied in a 
mirror-reversed manner, while the guide rod 24 is hinged on the fastening 
strip 30 and the work surface 20 in the same relation. 
The guide grooves 32 in the lateral legs 31 of the fastening strips 30 
receive the hinge bolts 22 of the work surface 20, so that the work 
surface 20 is guided in a vertically displaceable manner. The lower ends 
of the guide grooves 32 transition via transition sections 33 into holding 
receptacles 34 for the hinge bolts 22. The transition section 33 leads 
away from the door 10, and the holding receptacles 34 extend further 
upward, so that the holding receptacles 34 can receive and hold the hinge 
bolts 22, when in the work position the work surface 20 is pivotably 
stressed by its own weight around the axis formed by the hinge points 23 
and in this way is held in the holding receptacles 34. The essential 
portion of the guide grooves 32 extends vertically at a small distance 
from the door 10. Only in the area of the upper ends is the distance of 
the guide grooves 32 to the door 10 increased, so that in the stowed 
position there is sufficient space for the edge 21 of the work surface 20 
oriented toward the door 10. 
The hinge points 23 on the work surface 20 are located below the hinge 
bolts 22, and the hinge points 25 of the guide rods 24 at the fastening 
strips 30 are located lower than the holding receptacles 34. It is 
possible to fix the inclination of the work surface 20 in the work 
position by means of the dimensions of the guide rods 24 and the position 
of the hinge points 23 and 25, wherein preferably a position 
perpendicularly with respect to the door 10 is favored. However, the work 
surface 20 can also be in the work position slightly inclined downward 
toward the front. 
As FIG. 2 shows, in the work position the guide rods 24 are located below a 
work side of the work surface 20 and do not hamper in any way working on 
the work surface 20, so that objects extending past both sides can be 
placed on the work surface 20. 
If the work surface 20 is displaced from the stowed position in accordance 
with FIG. 1 into the work position in accordance with FIG. 2, the work 
surface 20 is grasped at the upper horizontal side and pivoted upward. In 
the process, the hinge bolts 22 slide downward in the guide grooves 32 
until the hinge bolts 22 reach the transition sections 33. The work 
surface 20 is pulled forward and released. The work surface 20 slightly 
pivots upward under its own weight, because the hinge bolts 22 are 
inserted into the holding receptacles 34. The work position of the work 
surface 20 is fixed, it is not changed even when a load is placed on the 
work surface 20. 
If the work surface 20 is again brought out of the work position in 
accordance with FIG. 2 into the stowed position in accordance with FIG. 1, 
the free side of the work surface 20 is slightly lifted. In the process 
the hinge bolts 22 are moved out of the holding-receptacles 34. By 
displacing the work surface 20 in the direction toward the door 10, the 
hinge bolts 22 are brought via the transition sections 33 into the area of 
the vertically arranged areas of the guide grooves 32. If the work surface 
20 is pushed downward at the front, it automatically returns into the 
stowed position because of its own weight when the hinge bolts 22 are run 
in, which position is reached when the hinge bolts 22 rest against the 
upper ends of the guide grooves 32.