|Title of Invention||
"A PLASTIC SPRING"
|Abstract||spring(l) comprising a resilient tongue (4) attached to a spring carrier(2) via a web(3) which is rigidly supported with respect to the spring carrier(2) and at least one additional resilient tongue(5, 6) which extends in the same direction as the resilient tongue(4)' from the web(2) below the resilient tongue(4). The spring characteristics of such a plastic spring is able to adapt to different conditions independently of the material .|
|Full Text||This invention relates to a plastic spring comprising a resilient tongue attached to a spring holder via a web.
Plastic springs can be used for a wide range of applications and are used,, for instance, a.s restoring springs a for the tablet ejector in tablet dispensers. Such plastic springs are mostly injection moulded along with the spring carrier in a single operation and have heretofore consisted of a bow-shaped web which terminates in a resilient tongue at its free end. For reasons of safety, the manufacture of the plastic spring and the spring holder requires the use of a material which does not involve the risk of injuries due to sharp edges, pointed elements or the like in case of spring rupture and, hence, the properties cf the plastic material used cannot be adjusted to the respectively required spring properties. Therefore, the known plastic springs are often too weak and do not meet the requirements as regards resiliency and deflection of the spring.
The object underlying the invention therefore is to eliminate these deficiencies and create a plastic spring of
the aforementioned type which can easily be injection moulded from the same material as the associated spring carrier, and whose resilient properties can nevertheless be readily adapted to different conditions.
This object is solved by the invention in that the web is rigidly supported with .respect to the spring carrier and at least one additional resilient tongue, which is unidirectional with the resilient tongue, extends from the web below the resilient tongue. Both the resilient tongue and the additional resilient tongue form a cooperating spring
- 1A -
assembly, whose resiliency increases with increasing spring deflection, because the resilient tongue, which is deflected under a load, will be supported by the underlying additional resilient tongue, following appropriate deflection, and the resiliency of the additional resilient tongue will then add to the resiliency of the resilient tongue. This increase in resiliency can be adjusted to the desired conditions by the number of the additional resilient tongues used, and the associated spring deflection will be influenced accordingly by the spacing between the resilient tongue and each additional resilient tongue. Therefore, the plastic spring may be injection moulded from an appropriate material that will be resistant to rupture even when subjected to higher loads, in which case the risky mounting region of the web is firmly secured as the web is braced towards the spring holder, and there is nevertheless obtained a spring whose properties can be adapted to the respective requirements.
When the resilient tongue and the additional resilient tongues have a length which decreases towards the spring carrier, the resiliency will increase progressively with spring deflection, as the rigidity increases with decreasing length, which fact is intensified by the space-saving arrangement of the resilient tongues which fit snugly into the location below the resilient tongue.
To take advantage of the material properties, the resilient tongue and the additional resilient tongues are of a width which tapers towards the free end of the tongues, which allows to equalize material stresses over the lengths of the tongues when the springs are subjected to load.
It is also advantageous to provide lateral cheeks serving as a prop between the web and the spring holder as these supporting cheeks do not only entail appropriate stability
of the web support, but a protective casing will also be formed, in a way, for the resilient tongue und the additional resilient tongues between the supporting cheeks and the web.
The subject matter of the invention is Illustrated by way
of example with reference to the accompanying drawing, wherein
Figs. 1 and 2 show a schematic side view and top view, respectively, of a plastic spring in accordance with the invention.
A plastic spring 1, which is injection moulded along with the spring holder 2 such as a tablet dispenser magazine, comprises a web 3 moulded to a spring holder 2, which changes into a transversely extending resilient tongue 4 and from which, for example, two additional resilient tongues 5, 6 project from beneath the resilient tongue 4 in the same direction, the additional resilient tongues 5, 6 being formed shorter than the resilient tongue 4 and the length of these additional springs decreasing progressively with increasing spacing from the resilient tongue 4.. In addition, the widths of the resilient tongue 4 and the additional resilient tongues 5, 6 may taper towards the free end of the tongues as shown in dash-dotted lines in Fig. 2. To provide a rigid support, the web 3 is connected with the spring holder 2 via lateral supporting cheeks 7, the supporting cheeks 7 and the web 3 providing some type of spring housing.
The resilient tongue 4 and the additional resilient tongues 5,6 form a spring assembly, whose individual resilient tongues cooperate in progressive steps under a load K, so that an increasing resiliency will result therefrom depending on spring deflection (see the dash-dotted lines in Fig. 1). It is thus possible to produce a plastic spring formed
- 3 -
from the same material as the spring holder, whose spring characteristics may readily be adapted to the respective requirements as regards deflection and resiliency.
- 4 -
We claim :-
1. A plastic spring comprising a resilient tongue attached to a
spring holder via a web, characterized in that the web (3) is
supported so as to be flexurally stiff with respect to the spring
carrier(2) and at least one additional resilient tongue(5, 6)
which extends in the same direction as the resilient tongue from
the web(3) below the resilient tongue(4).
2. The plastic spring as claimed in claim l, wherein the
resilient tongue(4) and the additional resilient tongues(5, 6)
have a length that decreases towards the spring carrier(2).
3. The plastic spring as claimed in claim 1 or 2, wherein the
resilient tongue(4) and the additional resilient tongues(5, 6)
have a width that tapers towards the free end of the tongues.
4. The plastic spring as claimed in one of the claims 1 to 3,
wherein lateral supporting cheeks(7) are provided between the
web(3) and the spring carrier(2).
spring(l) comprising a resilient tongue (4) attached to a spring carrier(2) via a web(3) which is rigidly supported with respect to the spring carrier(2) and at least one additional resilient tongue(5, 6) which extends in the same direction as the resilient tongue(4)' from the web(2) below the resilient tongue(4). The spring characteristics of such a plastic spring is able to adapt to different conditions independently of the material .
|Indian Patent Application Number||1745/CAL/1995|
|PG Journal Number||7/2007|
|Date of Filing||28-Dec-1995|
|Name of Patentee||HAAS BETEILIGULIGSGESELLSCHAFT M.B.H.,|
|Applicant Address||EDUARD HASS STRASSE 25, A-4050 TRAUN|
|PCT International Classification Number||F16F 3/087|
|PCT International Application Number||N/A|
|PCT International Filing date|