Note: Descriptions are shown in the official language in which they were submitted.
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JOINT CONNECTION BETWEEN TWO PLASTIC PARTS
Backqround of the Invention
The inv~ntion relates to a joint connection between
two plastic parts, wherein one part is at least partly
rotatable in relation to the other part.
As state of the art, such a construction is already
known. For example, West German Printed ~isclosure
3,014,578 shows a structure in which the two plastic parts,
one of which is designed as a bearing part and the other as
clamping jaw halves, are joined together through a joint
connection in the form of a short one-piece short hinge
strip. A disadvantags in this prior art construction,
which uses a hinge strip as the joint connectioll, is the
danger of breaking the hinge. In case of hard materials
this danger is considerable when bending through the
required bending range of about 90. There is also the
disadvantage of having a dependence on material of the film
hinge. That is, the whole construction must be adapted to
the shape of the hinge to achieve the desired elasticity.
In a so-càlled two-component injection molding
process, there is a further disadvantage that a material
must be used which is adapted to the shape of the hinge
part.
As an alternative to this known state of the art, it
is generally been known to produce two plastic parts singly
and then assemble them together. In which case, however,
high production and single parts costs result. For this
type of construction, two dies are needed for the
production of the corresponding parts, as well as different
bearing holding devices. Additionally, the two parts must
be assembled together in order to have a unit ready for
use.
The present invention attacks the problem vf
designing a construction of the kind mentioned so that
without regard to the material~ an improvement of the
hinging between two plastic parts can be provided with
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simpler and less expensive production.
This problem is solved, according to the invention, by
the fact that the joint connection consists oE a shell-form outer
element on the one plastic part and an inner element, at least
partly supported in the outer element, on the other plastic part.
Further, the two elements are made by injection molding one inside
the other, in a single die. In this way, the advantage is given
of a simple and cost-saving production, as a result of the use of
a single die in the joint zone. The two plastic parts are,
however, joined to~ether movably through the joint zone. Since
between the two plastic parts there is no connection in the Eorm
of a hinge, there is, advantageously, no longer any danger of
breaking at the turning point. Moreover, for the joint connection
according to the invention, there is no dependence on specific
material characteristics or properties. The joint connection is
ideally suited to hard materials. Furthermore, through the joint
connection of the invention with the loose connection between the
one and the other plastic part, a rotation range of up to 360 can
be reachedO
According to a first broad aspect of the present
invention, there is provided a plastics component comprising two
members articulated together by a connection such that they are at
least partially relatively rotatable, the connection having an
outer element which is ~ormed on one of the members and an inner
element which is formed on the other member and which is at least
partially located within the outer element, both elements being
moulded in the same mould, the inner element being moulded within
the outer element in the said mould, wherein said connection
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comprises two portions extending substantlally along the axis of
relative rotation of the two members, the element cross sections
of one portion corresponding to that of the other portion when
rotated through 180 relative thereto, but not otherwise.
According to a second aspect of the present invention,
there is provided a joint connection between two plastic parts,
one part being at least partially rotatable in relation to the
other part, characterizlng that the joint connection consists of a
shell-form outer element on the one plastic part, and inner
element at least partially supported in the outer element on the
other plastic part, wherein both elements are made by being
injection moulded one inside the other from one tool, and wherein
the outer and inner elements have, in each case, two axial
receiving zones angularly displaced by 180.
With reference to preferred embodiments, the inner
element of the plastic component is substantially pin-shaped and
in each of the portions of the connec-tion comprises a respective
pair of radially opposed flat and curved surfaces oriented in the
axial direction. Respective pairs of flat and curved surEaces of
the outer element correspond to and radially oppose the pairs of
flat and curved surfaces of the inner element.
The pairs of surfaces of the inner element preferably
extend towards the axial middle of the inner element, and a
connecting member is arranged between the axially adjacen-t pairs
of surfaces of the inner element. Furthermore, the outer element
preferably comprises radial openings in the region of the
connecting member.
With reference to further preferred embodiments, each of
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the said por-tions of the outer element has an inner surface
configuration comprising a planar and a curved surface and the
inner element has an outer surface configuration comprising a
curved and planar surface. Preferably, the said portions extend
to each other from respective opposed ends oE the connection.
The inner and outer elements of the component according
to the present invention may also define a cavity between the said
portions thereof preferably, this cavity is bounded by: (i) on
the outer element, respective opposed plane surfaces disposed
between the curved surface of the outer element in each said
portion and the planar surface thereof in the other said portion,
and respective further surfaces extending inwardly from said plane
surfaces to said planar surfaces; and (ii) on the inner element,
surfaces disposed oppositely to said further surfaces on the outer
element, and surfaces of a web interconnecting the parts of the
inner element in the portions of the connection.
Since for the joint connection according to the
inven-tion, there is no dependence on material, the best ma-terials
can be used in each case, especially in a two-component inject:ion
molding process, which make possible a good adhesion between the
first and the second components.
If the joint connection according to the invention is to
absorb greater forces, this can be achieved at any time by
increasing the thickness dimensions of the inner and outer
elements.
The invention will be explained in detail below with
reference to pre-ferred embodiments illustrated in the drawings
wherein:
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Figure 1 shows a side view of a :Eirst embodiment of
joint connection formed in accordance with the lnvention;
Figure 2 shows the joint connection according to Figure
1, in frontal view, partly broken away;
Figure 3 is a side view of a second embodiment of joint
connection of the invention;
Figure 4 shows a vertical radial section through the
joint connection according to Figure 3;
Figure 5 shows in side view possible embodiment of joint
connection according to the invention;
Figure 6 shows a vertical radial section through the
joint connection according to Figure 5;
Figure 7 shows a frontal view of one form of the joint
connection according to the invention used in a fastening element;
Figure 8 shows in front elevational view another
possible embodiment of the joint connection according to the
invention; and,
Figure 9 shows a top view partly broken away of the
join-t connection according to Figure 8.
Referring more particularly to the drawings wherein the
showings are for the purpose of illustrating preferred embodiments
of the inven-tion only, and not for the purpose of limiting same,
Figure 1 shows, in somewhat diagram form, a plastic part 1, which
is connected through a joint connection 3 with a second plastic
part 2. Here, the joint connection 3 is comprised of a shell-
form, outer element 4 on the one plastic part 1. An inner element
5 is formed on the other plastic part 2. Inner element 5 is
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somewhat cylindrical and is at least partly supported in the outer
element 4. Both elements 4 and S are made by being injected one
inside the other ~rom one tool.
As can be seen, the outer element 4 has an at least
partly circular circumferential open zone. In the open zone is
supported the inner element 5. PreEerably the element 5 is
designed in a generally peg or axle form and is spaced from outer
element 4 over an interspace or gap 7~ Between the two elements 4
and 5 is -formed a breakable spacer piece 6. Piece 6 is designed
to be broken with the action of the joint connection, so that then
the peg-form inner element 5 can move, joint-like, in the shell-
like outer element 4. For a better adapting of the rotational
properties, there may be provided an opening 8 or circular slot in
the outer element 4. The opening or slot 8 is preerably
equidistant from the circular circumferential zone or interspace 7
in surrounding relationship thereto. The inner element 5,
designed in peg form, is connected with the plastic part 2 through
a stay or connecting web 25. With this design, the swinging
allowed the joint connection according to the invention depends on
the thickness of the stay 25 and the size of the opening of the
outer element 4 in the zone about the stay 25.
In the embodiment according to Figs. 3 and 4, the outer
element 4' and the inner element 5' have, in each case, two axle
receiving zones I and II which are side-by-side but rotated by
180. Here, the particular zone of the outer element 4' is
hounded by a flat end surEace 9 and an arched end surface 10.
From Fig. 4 it can be seen that in zone I, the flat end
surface 9 lies above, and in zone II, the flat end surface 9 lies
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be]ow. The arched surfaces 10 in zones I and II lie
correspondingly diagonal.
The particular zone of the inner element S is here
designed as a peg, with an arched surface 11 and a Elat surface
12. Thus, each axle receiving zone of the inner element 5
approximates a segment of a circle bounded by an arc and a chord.
As can be seen further from Fig. 4, in the zone I the flat surface
12 is above, and thus lies opposite the flat end surface 9 of the
outer element 4'. The arrangemen-t in zone II corresponds. In
this way th~ere is given a greater degree of freedom of the joint
connection according to the invention, because of the interspaces
between the surfaces 10 and 11 and the surfaces 9 and 12.
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In the embodiment according to Fig. 5, the inner
element and the outer element each have an opening 13, 14
respectively located in the middle between the two zones I
and II. As seen in Figure 6, the openings 13 and 14 are
formed by a flat surface 15, lying at a distance from the
particular arched end surface 10, and by surfaces 16 and
17. Surface 16 is arrangsd perpendicular to end surface
10, in the outer element. Vertical surface 17 is located,
at a distance from the surface 16 of the outer element, and
is perpendicular to a connection part 18 between the two
zones of the inner part 5'. As can be seen, the opening 13
or 14 is bounded by the surfaces 15 and 16 in the middle
zone of the outer element 4'~ and by the surface 17 and the
intermediate part 18 of the inner element 5'.
The embodiment shown in Figures 5 and 6, is an
extension or modification of the construction according to
Figs. 3 and 4, and provides a further degree of freedom for
the joint cvnnection according to the invention.
Specifically, the plastic part 2 can also be moved in the
axial direction in relation to the plastic part 1. The
distance of axial movement permitted corresponds, of
course, to the width of the opening 13 or 14.
Figure 7 illustrates the use of the joint connection
as shown in Figures 3 and 4. Here a fastening element 19
is chosen as starting point. Element 19 has two shell-like
elements 20 and 21. Element 21 carries the inner element
5' in a manner similar to the plastic part 2 represented in
Figs. 1 to 6. The outer zone, that is, the outer element
4', is arranged in the bearing part of the fastening
element 19, similar to the plastic part 1 in the
embodiments according to Figures 1 to 6.
The outer element 4', as well as well as the inner
element 5', is shaped similar to the construction shown in
Figs. 3 and 4; that is, with arched and flat surfaces. As
can be seen, by this construction the shell element 21 can
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cover a great swinging range, and is thus more elastic in
its mobility than the shell element 20 fastened to the
corresponding bearing part through a prior art film hinge.
However, there is also the possibility to arran~e the shell
element 20, similar to the joint connection o~ the shell
element 2l, on the corresponding bearing part.
In Figs. 8 and 9 is shown another possible
embodiment of joint connection according to the invention.
As can be seen, in this embodiment the outer element 4" has
a smooth, closed circumferential zone which is formed by a
ring 22. The inner element 5' is designed in peg form and
is supported in the ring 22 through the peg 23. Here, in
the drawing according to Figure 8, there is a significant
interspace between the peg 23 and the ring 22, but
according to the shape o~ construction this space may be
designed smaller. ~he outer element 4" is arranged in the
plastic part l through a stay 24; the inner element 511 i5
fastened, in turn, through a stay 25 to the plasti.c part 2.
All the above-mentioned joint connections accordiny
to the invention are produced by being iniected one in the
other, in the joint zone, from a single tool, while the two
plastic parts l and 2 are connected movable relation to
each other, in the corresponding joint zone ~. As a result
of this joint connection, there is no danger of breakage at
the point of rotationO While for the shaping of the joint
connection according to the invention, as a ~urther
advantage, there is no dependence on material.
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