Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Multiple contact type
Reexamination Certificate
2001-03-29
2003-04-15
Donovan, Lincoln (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Multiple contact type
C335S130000, C335S132000
Reexamination Certificate
active
06549108
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns a safety relay with at least one electromagnetic drive, which comprises a coil with a core/yoke that can be connected to a control current and a movable armature. The relay also comprises a comb that can be moved by means of the armature and several contacts arranged on an electrically insulating carrier part. The drive is arranged on one side of a separating wall; comb and contacts are on the other side of the separating wall. The invention particularly concerns a twin relay of the aforementioned type. The twin relay is a safety relay with two electromagnetic drives. These drives are arranged on one side of a separating wall. Two combs and two rows of contacts are arranged correspondingly on the other side of the separating wall.
2. Brief Description of Art
A twin relay, which is approximately 15 mm high, 65 mm wide, and 76 mm long, and the structural height of which is formed by two planes, is described in WO 99/54,905. In one of the planes, for example on the side of the connections, two drive systems (opposite-poled sliding armatures) are accommodated. The contact sets are arranged in the other plane. The contact sets each are formed by two contacts individually driven by one of the drives that are independent of one another, and these contacts are connected internally in series. The contacts are formed by one or two contact springs. If a contact is formed by two contact springs, then the active or the passive contact spring extending over the entire width or length of the relay is clamped in the center in a chamber separating wall, and possesses a contact head on both ends. This contact head cooperates with a contact spring, which has a terminal connection on the outside of the relay. If the individual contact is formed of a single contact spring only, then the latter is forcibly-commutated together with the comb and its contact head cooperates directly with the contact head of the contact spring of the other contact of the contact set. This contact spring of the second contact is in turn forcibly-commutated together with a second comb. The two combs each move in opposite directions. The contact springs extend parallel to a separating wall between the two planes. The prior art document is silent with respect to the position and configuration of the drive with armature and comb.
Nowadays a relay must meet two partially contradictory requirements. These requirements must be considered in the development of new relays in order to be competitive in the marketplace. The first requirement is that relays must be made smaller. On the other hand it is required of the relays that they be durable and reliable. In a safety relay which meets EN (European Standard) 50205, the air paths and leakage paths between control contact and load contact comply with the requirements of standard IEC 61810-5 and IEC 664-1. The contents of these standards are known to the person skilled in the art and are included by reference. Depending on the voltage, the degree of contamination and the field of application, the known distances between conductive components of the different load contacts must be maintained. In addition, the forced commutation of the contacts further serves for purposes of safety.
In accordance with the present invention, a forcibly-commutated relay is a relay in which the contacts are forcibly-commutated with a common movable comb that is connected with the drive and in which at least one working contact and one resting contact are provided. Forcibly commutated here means that each time a contact element abuts a fixed stop, a movable contact spring cooperating with this contact element engages in the comb in such a way that it is forcibly moved together with the movements of the comb. With this constructive measure, it is ascertained that in case a contact is welded, either the welded contact breaks or the comb cannot be moved and thus the other contacts, including the resting contact, also remain in the position given by the welded contact.
BRIEF SUMMARY OF THE INVENTION
Thus, the object of the invention is to provide a safety relay of compact and simple construction, with which reliable, durable operation is assured. Preferably the relay is miniaturized. In addition the relay shall be easy to assemble and optimally adjustable.
The adjustment of the contacts forms an important aspect for assuring safety and durability of a relay. A sufficient adjustment of the contacts is more difficult to obtain the smaller the relay is and the smaller the clearances relative to the force equilibrium of the drive/spring and the 3-dimensional distances are selected. Thus high requirements are to be placed on adjustability in the case of a miniaturized relay.
The adjustability of the safety relay or the twin relay of the present invention is achieved in that the contact springs are arranged between the comb and the separating wall separating the drive side from the contact side.
The safety relay has at least one electromagnetic drive, which comprises at least one coil with a core/yoke that can be connected to a control current and a movable armature. This drive is arranged on one side of a separating wall which extends parallel to the core. A comb that can be moved parallel to the separating wall by means of the armature and a row of several contacts which are arranged on an electrically insulating carrier part are located on the other side of the separating wall. The contacts are comprised of at least two contact elements and can be actuated by the drive. At least one of the contact elements is connected with a current connection element, for example a pin on the outer side of the relay. Likewise, at least one of the contact elements is formed by an elongated contact spring. The longitudinal axis of this contact spring is arranged transverse to the direction of motion of the comb and extends advantageously parallel to the plane of the separating wall. The contact spring is forcibly-commutated by the comb. The contact spring with its spring foot on one end is accomodated firmly in the carrier part. On its opposite movable end it is provided with a contact head. For an optimal construction of the relay, the contact springs are arranged between the comb and the separating wall. With this construction, the length of the armature can take up the entire height of the relay, and a relatively large comb path is achieved with relatively small structural height.
Advantageously, a removable outer wall of the contact chamber on the comb side of the contact spring that lies opposite the separating wall for closure of the relay. This allows one to insert the comb into the carrier part after introducing the contact elements, and holding it in its catching position by means of the outer wall of the chamber. If the contacts can be arranged in a functional manner in the opened relay, it is assured by this arrangement that the contacts can be optimally adjusted. When adjusting the contacts, the contacts are firmly secured in the carrier part, are not in engagement with the comb, and are freely accessible from the open outer wall of the chamber. In order to control the adjustment, the comb can be temporarily inserted with the relay still open. Only after the correct adjustment has been controlled, the comb is definitively inserted and the outer wall of the chamber is put in place, and thus the relay is sealed.
Preferably, the individual contacts are separated from one another by chamber walls. Advantageously, the comb is formed by a longitudinal bar extending through cutouts in the chamber walls. This longitudinal bar can be arranged in the vicinity of the contact springs and is engaged with the contact springs by means of suitable formations on the bar. Due to the drive arrangement, the longitudinal bar is advantageously arranged in the center between the outer edges of the relay or relay part. Shields are provided on at least three sides of the longitudinal bar, which are arranged approximately parallel to the chamber walls and extend be
Donovan Lincoln
Elesta relays GmbH
Nguyen Tuyen T.
Simons Williams A.
Wiggin & Dana
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