Electrical connectors – Contact comprising cutter – Insulation cutter
Reexamination Certificate
1999-04-14
2001-07-03
Abrams, Neil (Department: 2839)
Electrical connectors
Contact comprising cutter
Insulation cutter
C439S413000
Reexamination Certificate
active
06254420
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device for making, in one action, the so-called insulation-displacing connection (“I.D.C.”) of one or more electrical or telephone wires, and for cutting the scrap at their free end, downstream of the point of connection.
BACKGROUND OF THE INVENTION
Documents EP-A-0 092 953 and EP-A-0 519 842 disclose connection devices of rotating type which effect, on one wire, the insulation-displacing connection and cut of the useless scrap at the free end of this wire, by a movement of rotation of a barrel integral with the device, which is rotated with the aid of a screwdriver introduced in a slot provided to that end on this barrel.
According to document EP-A-0 092 953, the wire must firstly be introduced in a through orifice forming part of the device, this bringing about considerable difficulties in wiring, in particular when these devices equip terminal blocks for interconnection of lines (typically telephone or computer-related lines) and when these terminal blocks are very close to one another, consequently rendering access to these orifices difficult. Moreover, such introduction in a necessarily small orifice is an operation requiring a certain degree of attention, and which is tiring for the assembler who, after a certain time of work, might begin to make defective connections.
The rotating connector according to document EP-0,519,842 does not present this drawback and is therefore improved over the preceding one (which, moreover, is older), as the wire to be connected is introduced, via the top of the connector, in a receiving slot of this connector (it is then said to be “combed” in this receiving slot). Accessibility is therefore largely improved, even if the terminal blocks are very close to one another. In addition, as it is necessary to grip the wire at two places (one upstream and the other downstream) in order to be able to “comb” it in its receiving slot, the wire is guaranteed to be totally introduced in this slot, which is not the case when this wire must be introduced with one hand in a through or blind orifice and when it is not always possible to see the end of this wire project on the other side.
On the other hand, although it is largely improved on that point, the connector according to EP-0,519,842 presents a few drawbacks:
It only allows one wire to be wired at a time, while it would be much quicker and more logical to wire the two wires of one pair at the same time, in one and the same operation;
It necessitates, in a terminal block, a connection of relatively large dimensions compared to that desired at the present time where compactness is an absolute requirement;
With the dimensions imposed at the present time for this type of rotating connector, it is impossible for it to wire and cut wires whose core has a cross-section greater than 0.6 millimeters, as the effort to be developed would become too great for the structure of the connector to be able to withstand it without deforming. Now, it is desired at the present time, for telephone installations in particular, to be able to use wires whose diameter may go up to 0.8 millimeters. Unfortunately, it is not possible, for reasons of dimensions, to make terminal blocks with rotating connectors having a diameter greater than that adopted at the present time.
It does not indicate any means, animated by the reverse rotation of the barrel, to unwire (disconnect) the wire previously wired in the rotating connector, then to rewire it (connect again) by the turn of a screwdriver, although this would be very convenient for making test and corrective maintenance operations.
There is not sufficient space nor means to be able to embed, efficiently and rapidly, both the internal part of the connector and the cut end of the wire, in a gel or other like sealing product allowing these metallic elements to be protected against humidity if used outside.
It is necessary to use a screwdriver whose flattened end has a well determined width, adapted to the width of the barrel; if this flat end is too narrow, the force of rotation is insufficient and there is a risk of the connector being damaged, and if, on the contrary, this flat end is too wide, it cannot enter the slot provided on the barrel.
It is complex, therefore expensive, to produce a metallic contact of cylindrical form by cutting out flat, then winding, and this operation furthermore necessitates a quantity of metallic material much larger than that necessary for making a simple flat contact, this further increasing the cost price of the connector.
The very design of this connector means that a considerable torque is created when the wire is connected, especially if it is a wire whose diameter is greater than 0.6 mm, by rotation of the barrel. This torque tends to deform the cylindrical outer part of the connector, which may bring about deterioration of the connection device.
Document GB-2,097,201 may also be mentioned as prior art. It describes a connection device using, for connecting a sheathed wire, an I.D.C. contact, a connection pusher, and a blade for cutting the scrap. With this device, the scrap is cut just at the end of the connection operation via the insulation-displacement slot of the I.D.C. contact, and the free end of the wire then remains in electrical contact with the cutting blade. This is very damaging, particularly in a damp environment where phenomena of electrolysis may be created on the cutting blade in that case dampened and still electrically connected to the corresponding line wire.
It is an object of the present invention to overcome these drawbacks.
SUMMARY OF THE INVENTION
To that end, the invention relates to a device for making, in one action, the insulation-displacing connection, or “I.D.C.”, of one or more electrical or telephone wires, and for cutting the scrap at their end, this device comprising:
an insulating base which forms a cavity in which are implanted the I.D.C. contacts for receiving the electrical wires,
opposite each I.D.C. contact and parallel thereto, a blade for cutting the scrap,
a connection pusher which comprises lateral slots for introduction of the wires and which is associated telescopically with said base, characterized in that said cutting blade is dimensioned and positioned so as to be sufficiently after the bottom of the insulation-displacing slot of the I.D.C. contact associated therewith, for the electrical wire to arrive, when it is totally connected, at a distance from this cutting blade.
This device is preferably designed to receive two wires to be connected in the same movement of the pusher, and in that case it comprises a master screw which is placed between the two respective “cutting blade—I.D.C. contact” pairs, each associated with one of the wires to be connected.
In that case, the assembly is preferably symmetrical with respect to the transverse plane which passes through the axis of this screw and which is orthogonal to the two I.D.C. contacts and to the two cutting blades.
Likewise, said base and said pusher are preferably designed to form, when they are enclosed in each other, a virtually closed reservoir for containing a gel or other like sealing product for protection against outside aggressions, such as dust and humidity.
The pusher advantageously forms, beyond the space which receives each I.D.C. contact, a reserve of gel or other like product which overhangs and envelops this I.D.C. contact.
REFERENCES:
patent: 4370009 (1983-01-01), Dola
patent: 4444447 (1984-04-01), Markwardt
patent: 5139440 (1992-08-01), Volk et al.
Bonvallat Pierre
Letailleur Jean-Pierre
Abrams Neil
Gilly Richard P.
Pouyet S.A.
Zarroli Michael C.
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