Device for connecting a spring with a belt-shaped or rope-shaped transmission element

A device for connecting a spring to a band-like or cable-like transmission apparatus. The device being easy to assemble and in which the risk of fracture of the device is greatly reduced. The device provides a connecting part to be fitted on the transmission apparatus and a hook-in part to be connected onto the spring. The connecting part then being connected to the hook-in part to connect the transmission apparatus to the spring.

BACKGROUND OF THE INVENTION 
FIELD OF THE INVENTION 
The invention relates to a device for connecting a spring to a band-like or 
cable-like transmission means. 
Such connections are required, e.g. in domestic appliances with a door 
which can be pivoted around a horizontal spindle and is mounted on a 
housing, for the purpose of compensating the weight of the door in order 
to facilitate the handling, in particular the closure, of the door for the 
user. In this case, the weight is compensated by a spring, usually a 
tension spring, which is fastened on a housing and is connected to the 
door directly or by transmission means. 
German Utility Model 74 32 124 discloses such a device for compensating the 
weight of a domestic-dishwasher door which is located at the front of the 
dishwasher, can be pivoted around a horizontal spindle, is mounted on a 
housing and is connected, by means of a band-like or cable-like 
transmission means, to a tension spring fastened on the housing, in the 
case of which device the transmission means is fitted, in a manner which 
is not described, in an eyelet of the spring which has been produced by 
bending up the last winding of said spring. 
It has been shown, in practice, that the springs, which are subjected to 
very high stressing for the purpose of weight compensation in such a 
device, break, particularly at the eyelets produced by bending up the last 
winding of the spring, after a comparatively small number of load changes, 
that is to say door-opening movements. Furthermore, the insertion of the 
ends of the transmission means is time-consuming and thus expensive, and 
it is necessary to provide a fastening device on the transmission means, 
usually an eyelet, which constitutes a further operation and produces a 
further location which is at risk of fracture in a spring/transmission 
means connection. 
SUMMARY OF THE INVENTION 
The object of the invention is thus to provide, in a simple manner, a 
device for connecting a spring to a band-like or cable-like transmission 
means, which device is easy to assemble and in which the risk of fracture 
is avoided as far as possible. 
This object is achieved according to the invention in that the transmission 
means is fitted, by means of a connecting part connected fixedly to it, on 
a hook-in part connected to the spring. 
One of the abovedescribed locations which is at risk of fracture is 
effectively replaced by the fixed connection between the band-like or 
cable-like transmission means and the connecting part. Fastening the 
hook-in part on the spring effectively avoids the location which is most 
at risk of fracture, namely, as in the prior art, the last, bent-up 
winding of the spring, and thus effectively avoids the risk of fracture. 
Fitting the connecting part into the hook-in part renders assembly 
considerably easier than the insertion operation in the prior art. The 
inventive device for connecting a spring to a band-like or cable-like 
transmission means provides, in a simple manner, a device which is easy to 
assemble and in which the risk of fracture is avoided as far as possible. 
According to a preferred embodiment of the invention, in the receiving 
region for the connecting part, the hook-in part is in the form of a 
centrally slotted eyelet, of which the front and lateral delimitations are 
formed by two hooks whose ends project towards one another at a spacing 
apart, this further facilitating assembly. 
In a particularly advantageous manner, the connecting part is in the form 
of a flat plate which, in two regions arranged one beside the other at a 
spacing apart, is offset at least by the thickness of the hook-in part, 
this resulting in further-simplified positioning of the connecting part 
according to the invention in the hook-in part according to the invention 
being possible without the reliability of the connection being reduced. 
The connecting part is placed on the hook-in part, for example, from 
above, the front ends of the offset regions coming to butt against the 
inner edges of the hooks of the hook-in part as a result of the stressing 
of the spring in the use state. 
Expediently, the spacing between the offset regions at most corresponds to 
the spacing between the ends of the hooks of the hook-in part, thus 
achieving additional guidance of the inserted connecting part. 
Assembly is facilitated further in that, at the ends of the offset regions, 
said ends being situated opposite the transmission element, the connecting 
part has a region which is overlapped by a plate, at least a spacing 
corresponding to the thickness of the hook-in part remaining between the 
underside of the plate and the surface of the offset regions since the 
overlap makes it possible for the loose connecting part to be secured on 
the hook-in part even before stressing of the spring commences. 
Advantageously, the slotted eyelet is of an essentially rectangular shape 
with essentially rectangular hooks, and the connecting element is of an 
essentially cuboidal shape, as a result of which it is easy to produce the 
parts of the device according to the invention. 
In a particularly advantageous manner, the inner edges of the hooks, which 
form a delimitation of the eyelet opening, and the end surfaces of the 
offset regions are arranged so as to be inclined, in the direction of the 
spacing, towards the eyelet opening, which, as a result of the 
hooking-behind action and of consequently improved securing, means that 
assembly is facilitated further. 
The transmission means is preferably a cable produced from a thermoplastic 
synthetic material. It has been shown, in practice, that, for example, 
steel cables wear more quickly than synthetic material cables. 
One transmission means which has been shown to be particularly durable in 
practice is a braided cable made of polyester. 
Particularly simple production and a particularly fracture-resistant 
connection between the connecting part and the transmission element is 
provided by the connecting part being produced so as to encapsulate the 
transmission element. 
The connecting part is preferably produced from polyoxymethylene (POM) this 
having proven to be particularly fracture-resistant in practice. 
BRIEF DESCRIPTION OF THE DRAWING 
FIG. 1 shows a section through a base of a domestic dishwasher, and 
FIG. 2 shows an enlarged illustration of the device according to the 
invention, the illustration corresponding to the detail II in FIG. 1. 
FIG. 3 is a cross-sectional view of a connecting part taken along the line 
III--III shown in FIG. 2; 
FIG. 4 is a cross-sectional view of the connecting part taken along the 
line IV--IV shown in FIG. 2; and 
FIG. 5 is a cross-sectional view of the connecting part taken along the 
line V--V shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A domestic dishwasher (not explained in any more detail) has a door 2 which 
is located at the front, can be pivoted around a horizontal spindle 3 and 
is mounted in a machine base 1, which is part of a housing. This door 2 is 
connected, in a manner which is not described in any more detail, on both 
sides of the front of the machine base 1 by means of in each case one 
hinge 4 connected to the door 2. A device 10 for weight compensation 
comprises a tension spring 5 which is fastened in the machine base 1 and 
is connected to the door 2, or, in the exemplary embodiment, to the hinge 
4, by means of a band-like or cable-like transmission means 11, in the 
depicted exemplary embodiment by means of a cable 11 made of a 
thermoplastic synthetic material, preferably a braided cable 11 made of 
polyester. This cable 11 butts, with stressing, against a deflection 
roller 17, arranged in a carrier 12 fastened in the machine base 1, and 
partially encloses said deflection roller. 
According to the invention, the transmission means, in the exemplary 
embodiment the cable 11, is fitted, by means of a connecting part 21 
connected fixedly to it, on a hook-in part 30 connected fixedly to the 
spring 5, as can best be seen in FIG. 2. 
In the receiving region for the connecting part 21, the hook-in part 30 is 
in the form of a centrally slotted eyelet 31, of which the front and 
lateral delimitations are formed by two hooks 32, 33 whose ends 34, 35 
project towards one another at a spacing x apart. 
The connecting part 21 is in the form of a flat plate which, in two regions 
22, 23 arranged one beside the other at a spacing y apart, as shown in 
FIG. 3 is offset at least by the thickness of the hook-in part 30. 
According to the invention, this distance y between the offset regions 22, 
23 at most corresponds to the distance x between the ends 34, 35 of the 
hooks 32, 33 of the hook-in part 30. In the depicted exemplary embodiment, 
the distance y between the two offset regions 22, 23 is selected to be 
somewhat smaller than the distance x between the ends 34, 35 of the hooks 
32, 33, in order to facilitate the operation of fitting the connecting 
part 21 in the hook-in part 30. 
At the end of the offset regions 22, 23, said end being situated opposite 
the transmission element, the connecting part 21 has a region which is 
overlapped by a plate 24, at least a spacing corresponding to the 
thickness of the hook-in part 30 remaining between the underside of the 
plate 24 and the surface of the offset regions 22, 23 as shown in FIG. 4. 
In FIG. 2, a plate above the offset region 22 is left out in order for it 
to be possible to illustrate the hook 33 more clearly. In FIG. 5, there is 
shown a cross-sectional view of the rear part of the connecting part 21. 
In the exemplary embodiment, the slotted eyelet 31 is of an essentially 
rectangular shape with essentially rectangular hooks 32, 33, the inner 
edges 36, 37 of the hooks 32, 33 which form a delimitation of the eyelet 
opening, being arranged so as to be inclined, in the direction of the 
spacing x, towards the eyelet opening. The connecting part 21 is of an 
essentially cuboidal shape, the end surfaces 25, 26 of the offset regions 
22, 23 likewise being inclined corresponding to the inner edges 36, 37 of 
the hooks 32, 33. 
The connecting part 21, which is produced from POM, is produced so as to 
encapsulate the braided cable 11 made of polyester. 
The hook-in part 30 is fastened on the spring 5 by means of lateral 
projections 38, 39, a trapezoidal insertion aid 40 which is located 
opposite the eyelet 31 and adjoins the lateral projections 38, 39 being 
pushed into the spring 5 until at least the first winding springs over the 
outer edges of the lateral projections 38, 39 and encloses the hook-in 
part 30 in the vicinity of the eyelet 31. 
In the exemplary embodiment described, in order to adjust the spring force, 
the carrier 12, which has a projecting abutment stub 13, is mounted 
pivotably on the machine base 1, the pivot point 16 of the carrier 12 
being arranged at the greatest possible vertical spacing a from the 
door-bearing spindle 3. The cable 11 butts against the abutment stub 13 of 
the carrier 12 on a side situated opposite an adjustment screw 15. The 
adjustment screw 15 butts against that end of the carrier 12 which is 
located towards the door 2, remote from the pivot point 16 of the carrier 
12, for which purpose the carrier 12 has an abutment surface 14. The 
deflection roller 17 is mounted rotatably at the pivot point 16 of the 
carrier 12. The pivot point 16 of the carrier 12 is formed by a bearing 
bolt 18 which is fastened on the machine base 1 and on which the 
deflection roller 17 is also mounted rotatably. 
In order to increase the force of the tension spring 5, e.g. when a panel 
is fastened on the door 2 in order to match the domestic dishwasher with 
the front of kitchen fittings, this of course changing the weight of the 
door 2 which is to be compensated, the adjustment screw 15 is screwed in 
in the direction of the carrier 12, in which case it comes to butt against 
the abutment surface 14 of the carrier 12 and the latter is pivoted, 
around the bearing bolt 18 forming the pivot point 16 of the carrier 12, 
in the direction of the interior of the machine base 1, the cable 11 being 
carried along as a result of said cable butting against the abutment stub 
13. As a result of the cable 11 being acted on in this way, it is 
displaced out of the position in which the adjustment screw 15 is not 
activated, i.e. out of the angle by which it encloses the deflection 
roller 17 and which is predetermined in the rest position by the selected 
arrangement, which displacement results in the cable 11/tension spring 5 
assembly lengthening and, since the cable 11 cannot extend to any 
considerable extent, achieves extension of the tension spring 5 and thus 
an increase in the tension-spring force. In FIG. 1, the device 10 is shown 
with solid lines in the rest position and with chain-dotted lines in the 
position in which it has been pivoted to the maximum extent. 
If, once an increase in spring force has already taken place, the spring 
force is to be reduced again, then the adjustment screw 15 is 
correspondingly unscrewed from the machine base 1, this resulting in a 
shortening of the cable 11/tension spring 5 assembly and thus in a 
shortening of the tension spring 5, as a result of which a reduction in 
the spring force is achieved. 
For assembly, the connecting part 21 is positioned on the slotted eyelet 31 
of the hook-in part 30 from above, the web which is formed in the spacing 
y between the offset regions 22, 23 dropping into the slot formed by the 
spacing x between the ends 34, 35 of the hooks 32, 33. Thereafter, e.g. by 
pulling on the cable 11, the connecting part 21, which is now located in 
the eyelet opening, is moved in the direction of the hook inner edges 36, 
37 until the end surfaces 25, 26 of the offset regions 22, 23 butt against 
the hook inner edges 36, 37 and the latter are thus at least partially 
overlapped by the plates 24. The stressing of the spring 5 in the use 
state causes the front end surfaces 25, 26 of the offset regions 22, 23 to 
remain in abutment against the inner edges 36, 37 of the hooks 32, 33 of 
the hook-in part 30. 
The abovedescribed, inventive device 20 for connecting a spring 5 to a 
band-like or cable-like transmission means 11, in the exemplary embodiment 
to a cable 11, provides, in a simple manner, a device 20 which is easy to 
assemble and in which the risk of fracture is avoided as far as possible.