Fastening device for a switch

An assembly for switches of the type which are pushed into a receptacle by means of webs guided in grooves. On each guide groove one side wall is staggered backwards relative to the other side wall in the longitudinal direction. It is then possible to bring webs and grooves into contact by a vertical movement with respect to the direction of insertion.

BACKGROUND OF THE INVENTION 
The invention refers to a fastening device comprising the features of the 
preamble of claim 1. 
Such a device comprising a switch and a receptacle is known from the DE-OS 
27 19 194. Thereby the receptacle of the fastening device has two guide 
grooves which are arranged opposite to each other in two lateral walls. 
During the assembly two corresponding guide webs on the switch are 
inserted into the grooves and secure the switch in upward and downward 
direction. Into the other directions the position of the switch on the 
receptacle is secured by spring elements which are partly provided with 
detents with which they engage behind appropriate shoulders. 
It is an object of the present invention to develop the fastening device 
with the features of the preamble of claim 1 in such a way that the 
mounting of the switch on the receptacle is facilitated. 
This problem is solved by a fastening device having the features of the 
characterising part of the main claim. 
SUMMARY OF THE INVENTION 
According to the invention on each guide groove one side wall is staggered 
backwards relative to the other in longitudinal direction of the groove in 
such a way that the projecting portions of the longer side walls and the 
guide webs may be brought into contact by a vertical movement to the 
direction of insertion. When the fastening device is designed in such a 
way it is no longer necessary that at the beginning of the assembly the 
webs and the grooves have to be positioned exactly in a line, when they 
are brought to engage with each other. Now it is indeed possible to put 
the webs vertically on the respective longer side wall of the grooves and 
only then push them into the grooves. Thus not only the tedious and 
time-consuming putting-on at the beginning of the assembly is avoided to a 
far extent, but also the likelihood of a faulty assembly is diminished. 
Advantageous embodiments of the invention can be seen from the subclaims. 
Thus by further developments of the invention it is achieved that the 
guide webs and the guide grooves can in a particularly simple manner be 
brought into such a position to each other, from which they can be slid 
into each other. In another embodiment this is enabled by a straight 
relative movement between switch and receptacle. Thereby according to the 
invention the switch can also be easily brought into the proper position 
also in the second transverse direction to the longitudinal direction of 
the webs and grooves due to the design of the bottom of the groove in the 
area of the projecting portion of the longer side wall. This is especially 
simple, when the front faces of the bottom of the groove and of the side 
walls and/or of the guide webs are bevelled as guide surfaces which become 
effective during the movement by which the webs and the longer side walls 
are brought into contact. 
In spite of the design of the fastening device according to the invention 
it can indeed sometimes happen that the switch is put on the receptacle in 
the wrong manner. According to another embodiment it is provided in this 
case that the insertion path of the switch on the receptacle is limited. 
This is above all advantageous, if the switch is hold on the receptacle by 
means of resilient locking elements. Because of an appropriate design of 
the stops according to another embodiment the switch can easily be removed 
after a faulty mounting in order to be mounted properly thereafter. 
Thereby a faulty mounting can easily be recognised visually too, because 
the switch cannot be completely slid into the receptacle. 
Still other embodiments provide favourably arranged stops limiting the 
insertion path of the switch on the receptacle.

DETAILED DESCRIPTION 
The receptacle 10 of FIGS. 1 to 3 substantially consists of a cover 11, 
from which laterally two parts 12 are extending downwards. The lateral 
parts 12 are substantially shorter that the cover 11 as it can be seen 
especially clearly from FIG. 3. Their front ends 13 are thicker, so that a 
stage 14 is provided. 
On each side of the receptacle 10 there is a guide groove 15 which is 
staggered to the interior relative to the side parts 12 and which is 
formed by the two side walls 16 and 17 and the bottom 18 of the groove. 
The FIGS. 1 and 3 show that the lower side walls 17 are longer than the 
upper side walls 16 and the cover 11. The bottom 18 of the groove is as 
long as the side wall 17, in front of the shorter side wall 16 is widened 
beyond the width of the groove 15 and is flush with the cover 11. The 
front face 20 of the cover 11, the front faces 21, 22 of the side walls 16 
and 17 as well as the front faces of the bottom 18 of the groove are 
bevelled to form guide surfaces. 
The FIGS. 4 and 5 show a switch 30 which can be slid into a receptacle 10 
according to the FIGS. 1 to 3. For this purpose each side wall of the 
switch housing 31 is provided with a guide web 32 the cross-section of 
which corresponds to the cross-section of the assigned guide groove of the 
receptacle. There is a certain space between the webs 32 and the top 
surface 33 of the switch housing 31. At the rear end in direction of 
mounting which is designated by arrow A the webs are extending upwards as 
stops 34 as far as to the top surface 33. 
Below the webs 31 there is one holding spring 35 each with a detent 36. 
Behind the detent 36 the holding springs 35 are elongated to release keys 
37. Two further spring elements 38 are located on the front side 39 of the 
switch housing 31. These spring elements are vertically resilient to the 
holding springs 35. One holding spring 35 and one spring element 38 each 
are connected with the switch housing 31 via a common web not to be seen 
in the drawing. 
The fastening device according to the invention is permitting to put the 
guide webs 32 of the switch 30 on the lower and longer side walls 17 of 
the guide grooves 15 of the receptacle 10 and then to slid the switch 30 
into said receptacle. If in spite of this the switch were once put on in a 
faulty manner a stop 34 hits the lower side wall 17 as it is shown in FIG. 
6. Therefore the switch 30 cannot be pushed into the receptacle 
completely, so that the holding springs 35 with their detents 36 cannot 
engage behind the stage 14 of the lateral parts 12. Thus the switch can be 
removed easily. 
When the switch 30 is properly mounted as shown by FIG. 7 the stop 34 is 
located in the elongation of the shorter side wall 16. The switch could be 
slid into the receptacle without any difficulties, so that the holding 
springs 35 are locked. If now the switch has to be removed again from the 
receptacle 10 because of any reason the release keys 37 have to be 
pressed. As soon as the detents 36 are unlocked the switch 10 is a little 
bit pushed out of the receptacle 10 by the spring elements 38, so that the 
detents 36 no longer engage behind the stages 14 and then the switch can 
be removed easily at last. 
Further embodiments of a fastening device according to the invention with 
differently arranged guide grooves and guide webs and stops limiting the 
insertion path of the switch are shown in FIGS. 8 to 12. In the example 
according to FIG. 8 the lower side wall 17 of the guide grooves 15 is 
elongated in downward direction. As it is indicated in the drawing one of 
the guide webs 32 on the switch 30 hits this elongation, if the switch is 
put on diagonally. Thus it cannot be pushed in completely. Above all the 
lower side wall 17 can be easily elongated, when the guide grooves are 
directly below the cover 11 of the receptacle, so that the switch housing 
with the guide webs will have the shape of a T. 
An embodiment in which the width of the guide grooves 15 corresponds to the 
height of the switch 30 and the holding springs 35 are received in hollows 
45 in the bottom of the groove can be seen in FIG. 9. 
FIG. 10 shows a fastening device in which the receptacle 10 on its cover 11 
has a web 46 directed to the bottom which, when the switch is properly 
mounted, extends in a groove 47 of the switch 30. Of course the 
arrangement can also be reversed and include a web on the switch and a 
groove on the receptacle. If the switch is diagonally put on the 
receptacle 10 the web 46 hits one side wall of the groove 47, so that the 
switch 30 cannot be pushed in completely. 
According to FIG. 11 on the back wall 50 of the receptacle 10 there is a 
pin 51 and on the front side 52 of the switch 30 there is a recess 53, 
into which the pin engages with proper assembly. If, however, the assembly 
is faulty the pin 51 hits the front side 52 of the switch 52 and thereby 
limits the insertion of the switch. The same effect is achieved by a pin 
on the front side of the switch and a recess on the back wall of the 
receptacle. 
FIG. 12 finally shows an embodiment, in which the cover 11 of the 
receptacle 10 is overlapped by a lug 60 formed on the switch 30. The cover 
11 is partially located in the recess 61 formed by the switch 30 and the 
lug 60. If the switch is put on the receptacle diagonally the front side 
of the lug 60 hits the front side of the cover 11. 
When, due to a faulty assembly, the insertion movement of the switch on the 
receptacle is limited by stops, this does not only entail the advantage 
that the holding springs cannot engage, but the faulty assembly can also 
easily be recognised visually. Thus such a design of the fastening device 
according to the invention effectively supplements the development of the 
guide grooves and guide webs according to the invention. But it can be 
used with advantage even alone.