PIN BUSHING

DOUILLE DE BROCHE

English Abstract

The present invention relates to a pin bushing (1) with a receiving part (2)
for a pin (4) and a side connection part (3). The receiving part (2) forms a
bushing (5) with a base (6), two side walls (7a, 7b) and a roof zone (8), the
roof zone (8) comprising at least two tongues (9) alternatively radiating from
different side walls (7a, 7b) and extending transversely of the plug-in
direction, said tongues being bent over inwards into the bushing (5) in the
top zone of the opposite side walls (7a, 7b).

French Abstract

Douille de broche (1) comportant une partie réceptrice (2) pour une broche (4) et une partie de connexion latérale (3). La partie réceptrice (2) forme une douille (5) dotée d'une base (6), de deux parois latérales (7a, 7b) et d'une zone de couverture (8). Cette zone de couverture (8) comprend au moins deux languettes (9) s'étendant de manière alternée à partir de parois latérales différentes (7a, 7b) et s'étendant transversalement par rapport au sens de l'enfichage, lesdites languettes étant repliées vers l'intérieur dans la douille (5) au niveau de la zone supérieure des parois latérales opposées (7a, 7b).

Claims

C L A I M S
1. A pin bushing (1) with a receiving part (2) for a
pin (4) and a side connection part (3), characterised in
that the receiving part (2) forms a bushing (5) with a
base (6), two side walls (7a, 7b) and a roof zone (8),
the latter comprising at least two tongues (9)
alternately radiating from different side walls (7a; 7b) and
extending transversely of the plug-in direction, said
tongues being bent over inwards into the bushing (5) in
the top zone of the opposite side walls (7a, 7b).
2. A pin bushing according to claim 1, characterised in
that the tongues (9) at the upper end of the side walls
(7a, 7b) are bent and, from there up to their ends, are
straight.
3. A pin bushing according to claim 1, characterised in
that the tongues (9) are bent over their entire lengths
towards the interior of the bushing.
4. A pin bushing according to claim 1, characterised in
that the tongues extend obliquely downwards towards the
side walls (7b, 7a) from which they respectively extend.
5. A pin bushing according to claim 1, characterised in
that at least one inwardly projecting rib (10) oriented
longitudinally of the plug-in direction is disposed in
the base (6) of the bushing.

6. A pin bushing according to claim 5, characterised in
that the rib (10) is punched out at the longitudinal
edges thereof.
7. A pin bushing according to claim 5, characterised in
that the rib (10) is punched out at the longitudinal
edges thereof and is semicircularly bent in
cross-section.
8. A pin bushing according to one of the claims 1 to 4,
characterised in that a web (13) engaging around the
opposite edge of the bushing starts from that side wall
which is opposite the side wall (7a, 7b) from which a
tongue (9) starts.
9. A pin bushing according to any of the preceding
claims, characterised in that the cross-section of the
bushing zone (5) of the receiving part is substantially
rectangular.
10. A pin bushing according to any one of the preceding
claims, characterised in that when the pin part (4) is
plugged in the bent or bent-over part of the tongue
extends substantially parallel to the pin surface and is
pressed elastically against the latter.
11. A pin bushing according to claim 10, characterised
in that the distance between the ends (11) of tongues (9)
of opposite orientation is smaller, transversely of the
plug-in direction when the pin is plugged-in, than the
pin width (4).

12. A pin bushing according to any one of the preceding
claims, characterised in that the side connection part
(3) is a crimp connection part.
13. A pin bushing according to any one of the preceding
claims, characterised in that the side walls of the
bushing (5) comprise locking springs (12) for locking in
a casing.
14. A pin bushing according to any one of the preceding
claims, characterised in that the tongues (9) comprise,
at least in the roof zone (8), at least one reinforcing
rib (16) extending parallel to their longitudinal
dimension.
15. A pin bushing according to any one of the preceding
claims, characterised in that the front edges (15) of the
tongues (9) are rounded.
16. A pin bushing according to any one of the preceding
claims, characterised in that windows (14) are formed in
the side walls in the front zone of the bushing.
17. A pin bushing according to any one of the preceding
claims, characterised in that a cage (17) surrounds the
contact zone and has, at the entry end of the bushing, at
least one guide lip (19a, 19b) to guide the pin on its
introduction into the bushing.

Description

CA 022~7604 1998-12-09
W O 97/48149 PCTA~P97/03013
Pin bush; ng
This invention relates to a pin bushing in accordance
with the preamble of claim 1.
Pin bushings of this kind are used, individually or
combined in a plurality in casings, with matching pins in
order to produce plugged-in connections.
The quality of a plugged-in connection is governed by
secure hold of the pin in the bushing, and this is
dependent on mechanical properties and good electrical
contact or low transition resistance, which in turn
depends on the firm fit of the pin in the bushing.
The object of this invention is to provide an improved
pin bushing of small dimensions, suitable particularly
for heavy current, to guarantee a very firm fit of the
pin in the bushing, while ensuring low electrical
transition resistance by preventing fretting corrosion.
This problem is solved by the feature of claim 1.
Features of preferred embodiments of the invention are
disclosed in the subclaims.

CA 022~7604 l998-l2-09
W O 97/48149 PCTIEP97/03013
The resilient construction of the tongues which make
contact in the roof zone of the pin bushing ensures both
a firm fit of the pin in the bushing and also good
electrical contact. The latter is due to the fact that
even if a pin is tilted when introduced the tongues can
bear against the pin surface in the optimal manner.
The provision of a longitudinal rib in the bottom zone of
the bushing also ensures that in the event of the pin
being tilted there is adequate contact area between the
pin and the bushing.
The invention will be explained hereinafter with refe-
rence to the description of one exemplified embodiment
and the drawing wherein:
Fig. 1 is a side view and a plan view of the pin bushing
according to the invention and
Fig. 2a is a cross-section through the bushing zone of a
first embodiment of the pin bushing according to the
invention.
Fig. 2b is a cross-section through the bushing zone of a
second embodiment of the pin bushing according to the
invention.
Fig. 2c is a cross-section through the bushing zone of a
third embodiment of the pin bushing according to the
invention.
Fig. 3 shows a metal stamping from which the bushing is
made.
~'~~- T

CA 022~7604 1998-12-09
W O 97/48149 PCT~EP97/03013
Figs. 4a and 4b show the web surmounting the roof and
Fig. 5 shows windows provided in the front side walls of
the bushing.
Fig. la shows the pin bushing 1 from the side. The re-
ceiving part 2 is on the right. The cable connection part
3 is on the left. The tip of a pin part 4 is shown dia-
grammatically on the right next to the pin bushing 1. The
pin part 4 is plugged into the receiving part 2, which
has the shape of a substantially rectangular bushing 5.
Locking springs 12 are formed in the side walls of the
bushing part and lock the pin bushing, in a housing if
required.
The cable connection part 3 is in this case shown in the
form of a crimp connection part, although this has no
limiting force. Any other fixing technique is possible
here and, accordingly, any suitable construction of the
cable connection part 3.
Fig. lb is a plan view of the pin bushing according to
the invention and the tip of a contact pin 4. It will be
seen that the roof zone of the bushing 5 consists of,
tongues 9, the construction of which will be apparent in
detail from the description of Fig. 2. These tongues 9
are extensions of the side walls and are folded over
through about 90~ so that the top part thereof extends
substantially parallel to the bottom zone of the bushing.
In the example shown here, four tongues are distributed
over the roof zone of the bushing and each extend trans-
versely of the plug-in direction and are each formed

CA 022~7604 1998-12-09
WO97/48149 PCT~P97/03013
alternately on opposite side walls. Just before the op-
posite side wall, the tongues 9 are bent away obliquely
inwards and have a length so selected that the tips of
the tongues 9 terminate just before the side wall from
which the tongue projects. Fig. lb again shows the
locking springs 12 bent out of the side walls.
Fig. 2a is a cross-section through the bushing zone 5 of
a first embodiment of the pin bushing 1 according to the
invention, showing the shape of the tongues 9 more clear-
ly. It will be seen that the tongue 9 in the foreground
starts from the left side wall 7a and substantially its
first half forms the outer contour of the roof zone 8 of
the pin bushing. Just before reaching the opposite side
wall 7b, the tongue is bent inwards, care being taken in
respect of the angle of curvature to ensure that the
front zone of the tongue has maximum elasticity when bent
through the curvature zone, and to ensure that the front
tongue zone rests as flatly as possible on the outer
surface of the pin when the pin 4 is inserted. The
non-hatched tongue 9, which extends from the opposite
side wall 7b,is arranged in mirror-symmetry in relation
to the hatched tongue with respect to the central ver-
tical of the section shown in Fig. 2a. The tips 11 in the
unstressed position shown here are at a certain distance
from the side walls 7a, 7b, but this distance decreases
as soon as they are pressed upwards as a result of the
introduction of the contact pin 4. Preferably, the length
of the tongues is so selected that even when the pin 4 is
inserted the contact tips remain in contact with the pin
surface.

CA 022~7604 1998-12-09
W O97/48149 PCT~EP97/03013
Fig. 2b shows a second embodiment of the inventive pin
bushing which is considerably flatter in the bushing zone
as compared to the embodiment shown in Fig. 2a. This
comes from the fact that in the roof zone the tongues are
only slightly bent inwards instead of being fold back-
wards. In the embodiment shown in Fig. 2b the tongues,
seen from their ends, are unbent up to their base in the
upper area of the side walls. Only the bending fold at
the upper side edge is curved here.
Alternatively to the embodiment shown in Fig. 2a here
also the rib 10 in the bottom zone is designed diffe-
rently. Here the rib has a semicircular cross-section
which comes from the bottom part being punched out in the
area of the rib 10 along the longitudinal edges thereof
and the rib being subsequently bent upwards with the side
edges thereof.
Fig. 2c also shows a flat embodiment of the bushing zone,
in wnich, however, the tongues are slightly bent over the
entire length thereof, and in which the rib is punched
out of the bottom zone of the bushing along the longi~u-
dinal edges thereof.
By means of the punched-out ribs 10 also in the bottom
zone of the pin bushing it is ensured that in the case of
a tilted insertion of a plug lance an optimal electrical
contact is guaranteed, since the surface of the rib can
adap~ itself to the tilting to a certain extent.
Figs. 4a and 4b show an alternative embodiment wherein a
web 13 is formed at the top end of the right-hand side
wall 7b and surmounts the roof zone 8 of the bushing 5

CA 022 j7604 1998-12-09
W097/48149 PCT~P97/03013
and is bent on the left-hand side to bear against the
side wall 7a. A kind of cage is formed as a result which
effectively prevents unintentional opening of the
bushing.
A rib lO (Fig. 2) is provided in the bottom zone 6 of the
bushing 5 and extends in the plug-in direction. This rib
creates specific contact relationships with the pin 4,
since the flanks of the rib slope away on both sides to
ensure secure support of the pin surface.
Instead of the rib lO shown here with a flat platformlike
surface, it is also possible to provide two parallel ribs
of convexly curved cross-section if required. Since the
tips ll of the tongues 9 each exert pressure on the side
edges of the top surface of the contact pins, effective
pressure on the opposite rib lO is guaranteed.
This effectively compensates for any tilting on intro-
duction of the pin 4.
The electrical transition resistance is thus kept low and
the mechanical static friction between the pin and the
bushing is increased.
Fig. 3 shows a metal semiproduct consisting of a metal
stamping from which the contact bushing according to the
invention is made. The broken lines correspond to the
folding edges about which the metal is bent through 90~
in each case to form the contact bushing. Reinforcing
ribs 16 will be seen on the tongues 9, such ribs being
disposed on the longitudinal centre-line of the tongues 9

CA 022~7604 1998-12-09
WO97/48149 PCT~P97/03013
in the longitudinal direction to reinforce the tongues in
this zone.
The edges of the tongues 9 are rounded as will be
apparent from reference 15 in Fig. 3. Since these edges
may possibly come into contact with the pin, as will be
apparent from Fig. 2, it is important that there should
be no catching or damage to the coating of the pin at
this place, e.g. due to a sharp edge or a burr.
Figs. 4a and 4b show windows 14 in the side walls, in
addition to the web 13 already mentioned.
Fig. 5 shows the cage 17 disposed around the bushing zone
in order to protect it against opening up and guide lips
l9a, l9b which are provided in the receiving zone of the
bushing and which correctly position the pin on
introduction into the bushing.
The above description of one exemplified embodiment has
no limiting force. On the contrary, the invention covers
all possible variants within the scope of the claims.

Representative Drawing