Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Polarity-responsive
Reexamination Certificate
2000-04-19
2001-05-01
Barrera, Ray (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Polarity-responsive
C335S080000, C335S083000, C335S085000, C335S202000, C335S159000, C335S162000
Reexamination Certificate
active
06225880
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an electromagnetic relay with the following features:
a coil body forms a coil tube with two flanges and carries a winding on the coil tube;
a first of the two flanges forms a switch space with a base side parallel to the coil axis;
within the coil tube there is arranged an axial core which forms a pole face toward the switch space and is connected to an L-shaped yoke in the region of the second flange;
with its free end, the yoke forms, in the region of the switch space, a bearing edge, perpendicular to the base side, for a plate-shaped armature which forms a working air gap with the pole face of the core;
at least one, fixed contact support carrying a first fixed contact is secured in the coil body in the vicinity of the moving end of the armature and
a contact spring formed from flat strip material is connected to the armature, carries a moving contact at one free end in the region of the moving end of the armature and is connected to a contact spring connecting pin of the relay via a connecting portion.
A relay constructed in this way is known, for example, from U.S. Pat. No. 4,596,972. The contact spring there surrounds the armature mounting in the form of an arc and is fastened to the yoke by its connecting portion, the yoke in turn forming a downwardly shaped connecting pin. With a relay of this type, in which the load current is guided via the yoke, the current path in the relay to the connection is relatively long; the ferromagnetic yoke material also has limited conductivity. This is undesirable for the switching capacity of high currents if the connecting pin with its relatively small cross-section is also produced from the same material. A connecting pin shaped on the yoke also necessitates additional expenditure, if the relay housing is to be sealed.
In the case of similarly constructed relays which are designed for high load currents, it is known to guide the load current from a connecting pin fastened in a base via a flexible copper wire directly to the contact spring and to the contact piece fastened thereon (DE 34 28 595 C2). In this way, the yoke does not have to carry the load current. However, the use of the flexible wire necessitates additional expenditure for material and assembly.
With this known relay, the fixed contact supports and optionally also the contact spring connecting pin are produced as respective punched parts and are assembled by plugging them into preshaped ducts and apertures in the coil body or a base and then fixed by a notching process or inherent pressing. This design has the drawback that the parts do not fit in the plastic part in an interlocking manner for reasons of tolerance or that particles are abraded during assembly owing to overlapping of parts. These particles can subsequently lead to problems in the relay, for example on the contacts, in the armature bearing or in the working air gap. High expenditure then has to be incurred during production, to eliminate the resultant particles by blowing or extraction devices.
It is known with other relays to punch individual parts such as contact supports from sheet metal and to extrusion-coat them either individually or linked in strips in a mould. This method of production has the drawback that the parts have to be inserted into the injection mould; strip production also entails high consumption of material. High expenditure is required in both cases for adapting the injection mould to the punching tools, in order to allow the mould to be sealed well in the region of the punching burrs.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to create a relay of the type mentioned at the outset with a simple design, which can also be produced easily with few parts. In particular, the construction should allow the use of particularly desirable semi-finished materials and waste-free production processes which are particularly economical with materials, so that the relay can be produced particularly economically but still with high quality.
According to the invention, this object is achieved with a relay of the type mentioned at the outset in that the contact spring connecting pin and the at least one fixed contact support consist of drawn or rolled wire and are embedded in the coil body.
The use according to the invention of wire connecting elements for the load circuit connections allows particularly inexpensive production of the relay, which is economical in material. As the semi-finished wire is inserted into the injection mould directly from the supply roll and is embedded there, punching and bending tools are not required. The coil connections used in the normal manner are also preferably extrusion-coated in the mould in the same manner. The wire can be separated either before being extrusion-coated or after being extrusion-coated, directly by the injection moulding tool, without the formation of waste. The sealing of the injection mould is unproblematical owing to the use of drawn or rolled wires with a simple, preferably round or rectangular profile, as punching burrs or the like do not have to be allowed for. As the relay does not have any plugged-in punched parts, no plastic particles which could damage the contact surfaces or pole faces are shaved off during assembly.
In the simplest configuration, the relay has only one fixed contact which interacts with the contact spring as a make or break contact and is accordingly arranged on one or other side of the spring end with the moving contact. Similarly, however, a make-and-break contact can also be produced, in which case a second fixed contact support with a second fixed contact is secured in the same coil body flange opposite the first.
In a preferred embodiment of the invention, the contact spring connecting pin is also embedded in the first coil flange, in other words in the region of the switch space, and the connecting portion of the contact spring is fastened directly on a portion of the connecting pin extending parallel to the bearing edge of the yoke. The armature lies with its bearing end between the yoke end and the connecting pin in this case while the connecting portion of the contact spring is guided past the bearing end of the armature to the connecting pin and is fastened, preferably welded or hard soldered, thereon.
In an advantageous configuration, the contact spring connecting pin, like the fixed contact support, consists of square wire in each case. In this case, the contact springs on the one hand and the fixed contacts on the other hand can be welded or soldered with a large transitional area to the support. The fixed contacts themselves are preferably also separated from a semi-finished contact strip as portions, so no waste is produced here either.
The core arranged in the coil tube preferably possesses a pole plate with a pole face which is enlarged eccentrically toward the armature mounting. Therefore, even with small relay dimensions, on the one hand an adequate insulating distance from the fixed contacts and on the other hand a sufficiently large pole face can be produced. In an advantageous configuration, the core can be embedded in the coil body during production of the coil body, making a subsequent plug-in process unnecessary. In this case, the core can have a round or also a rectangular cross-section. However, it is also possible to plug a round (or rectangular) core into a through-orifice of the coil member at the later stage. In this case, it is advantageous to provide, on the core surface in the vicinity of the pole plate, embossed studs which form an interlocking fit during subsequent relaxation of the thermoplastic core body material and which therefore fix the core pole face and the bearing edge of the yoke reciprocally in position.
In an advantageous configuration of the invention, the contact spring is also fastened on the yoke by a fastening portion surrounding the armature mounting at an angle and a connecting portion folded over the fastening portion is guided to the connecting pin and connected to it. This ensures
Barrera Ray
Tyco Electronics Corp
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