Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Polarity-responsive
Reexamination Certificate
1999-01-11
2001-06-26
Donovan, Lincoln (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Polarity-responsive
C335S124000
Reexamination Certificate
active
06252479
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an electromagnetic relay having
a first housing part, which is fitted with a coil as well as a core which passes through the coil and, outside the coil, forms pole plates at its two ends,
a second housing part in which at least one spring support and at least one mating contact element are anchored, the spring support being fitted with a contact spring which interacts with the mating contact element, and
an armature which is connected to the contact spring and bridges the pole plates forming air gaps.
In addition, the invention relates to a method for producing such a relay.
EP 0 531 890 A1 describes a switching relay which is in principle constructed in the manner described initially. There, however, the two housing parts do not form a closed housing but only a base which is preferably a printed circuit board having an integrally formed side wall, and a cover part between which a large housing gap remains open even after the two parts have been joined together. The relay is preferably designed as a multiple relay having a row of magnet systems located alongside one another, a common core pole plate being located on the base and forming a row of vertically projecting core sections onto each of which a coil is fitted. Each system also has a U-shaped armature which is mounted on a core pole plate and, with the contact spring, encloses the coil like a frame. The cover part has slits with inserted mating contact elements and spring supports, and these slits likewise are not sealed. There, the contacts are clearly adjusted through the large housing opening in the region of the contacts.
WO 91/07770 has already disclosed a relay in which the magnet system is fixed in the upper region of a housing, while a contact system is pushed in from the open underneath until the contact closes when the magnet system is energized. Once this contact system has been pushed in further by a predetermined amount in order to produce a desired overtravel, it is fixed in the housing. This allows manufacturing tolerances to be compensated for even at the assembly stage, so that there is no longer any need for a subsequent adjustment.
DE-A-2 506 626 discloses a contact support for switching elements, which contact support can be closed by a housing and is composed of a dielectric. Armature contacts are mounted either in a glass tube or in a plastic frame as a support, and this support is closed on the outside by two housing caps. All the moving parts are housed there in one and the same support part, while the housing caps have no influence on the positioning of the functional elements of the relay.
EP-A-0 251 035 furthermore discloses a relay which comprises two base body parts which are in the form of half-shells, form a coil former and are fitted with the winding. Two pole plates are embedded in a common plane in one of the base body parts, and their ends are bridged in a contact space within the coil by means of an armature contact. The armature itself is fixed by a spring, in the form of a frame, which is in the separating plane between the two base body parts.
SUMMARY OF THE INVENTION
The aim of the present invention is to provide a relay of the type mentioned initially and having a flat design, which is designed for different sizes and applications and which can be produced in large quantities very cost-effectively, using the appropriate manufacturing methods. At the same time, a high degree of accuracy is intended to be achieved as early as the manufacturing stage by virtue of the design, so that the relay characteristics are maintained with only small tolerances, even without subsequent adjustment.
This aim is achieved according to the invention in the case of such a relay in that the two housing parts, which are joined together at their edges to form a seal, are roughly trough-shaped half-shells made of plastic, while the connections for the coil winding and for the contact elements are each passed out through the walls of their respective housing parts, and in that the main joint planes between the two housing parts are at right angles to the switching movement of the contact spring.
In the case of the relay according to the invention, the two half-shells not only form a housing which is easy to seal, but they are also used as support for the functional elements of the relay, and these functional elements, that is to say the magnet system in the one part and the contact system in the other part, can be positioned very accurately as early as during the manufacture of the respective half-shell. The main joined planes between the two housing parts are preferably at right angles to the switching movement of the contact spring, so that the distance between the magnet system and the contacts can be adjusted by the joining together of the two housing parts. The fixing of the functional parts in the housing and the sealing of the connections are achieved particularly easily by embedding them in the respective housing half-shell. The joint planes are composed of plastic, preferably a thermoplastic, so that a sealed connection can be produced, for example by means of ultrasound, in a simple manner.
In one preferred embodiment, the magnet system is formed by a U-shaped core yoker plate, which is preferably embedded in a plastic coil former in the same way as at least two coil connections. The pole plates which are formed at the two ends of the core then extend at right angles to the core axis in the region alongside the coil, where they are bridged by an armature which is located alongside the coil. This armature may be designed to a greater or lesser extent as a flat metal sheet or may be bent at different levels at the two ends in order to interact with the pole plates, which are likewise correspondingly offset in height. This makes it possible to optimally utilize space in the housing to accommodate the contacts and the various connections. An L-shaped contact spring has one limb which extends at the end in front of the coil and the other or second limb which extends alongside the coil underneath or above the armature, and this structure results in a long spring length in a confined space. The armature is preferably attached to the contact spring in the transition region between the two spring limbs.
A preferred method for producing the relay, according to the invention, comprises the first housing part being produced by embedding the coil with the core including the coil connections, by the second housing part being produced by embedding the spring support and at least one mating contact element, by the contact spring, which is connected to the armature, being connected to the spring support, and by the edges of the two housing parts then resting on one another and being connected. In this case, the coil former is preferably also formed in advance by embedding the core and the coil connections, the first housing part being produced by a second embedding process after the winding of the coil and after the connection of the coil ends to the coil connections. Before the two housing parts are joined together, the armature is connected to the contact spring, an electrically conductive connection being possible by welding or the like, or an insulating connection by means of extrusion coating, depending on the application. The contact spring is then electrically conductively attached to the spring support which is anchored in the second housing part, for example by welding or else via a plug-in attachment.
A major advantage of the invention may also be regarded as being that the contact overtravel can be adjusted during the process of joining the two housing parts in that, the seal-in voltage of the armature is measured for example during the joining process, and the joining process is then interrupted when a predetermined seal-in voltage electrical characteristic is. This characteristic is a measure of the amount of erosion or the overtravel of the contact. Instead of being connected by ultrasound or some other welding method, the two half-shells can alt
Kern Josef
Polese Angelo
Donovan Lincoln
Schiff & Hardin & Waite
Tyco Electronics Logistics AG
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