Electricity: circuit makers and breakers – Interlocking – Drawout-type switchgear
Reexamination Certificate
2001-08-30
2002-11-12
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Interlocking
Drawout-type switchgear
C200S050260, C200S318000, C200S325000
Reexamination Certificate
active
06479770
ABSTRACT:
The present application hereby claims priority under 35 U.S.C. §119 of German application number 10044058.4 filed in Germany on Aug. 31, 2000, the contents of which are hereby incorporated by reference in their entirety and for all purposes.
FIELD OF THE INVENTION
The invention relates to a field of basic electrical components and is applicable to the design configuration of an electrical switch. More preferably, the switch includes a release by means of which the movement of a switching contact arrangement of the switch from a closed switch position to an open switch position can be initiated. Still further, the switch preferably includes a locking mechanism for an interchangeable release block, which accommodates the release. By means of the locking mechanism, the release block can preferably be secured to prevent it from being removed from the switch.
BACKGROUND OF THE INVENTION
In a known electrical switch of this type, which is in the form of a manually operated circuit breaker, the locking mechanism has a locking element which can be moved from a locked position to an unlocked position and has a first operating surface by means of which the release block is secured to prevent it from being removed from the switch when the locking element is in its locked position. This locking element is formed by a manual operating toggle, which can be rotated. In this case, when the circuit breaker is operated correctly, the closing of the switching contact arrangement can be initiated by rotating this manual operating toggle into its locked position (ON position). Further, the opening of the switching contact arrangement can be initiated by rotating this manual operating toggle into its unlocked position (OFF position) (DE 36 42 719 A1).
In the event of a serious defect, in which the switching contact arrangement remains closed even though the manual operating toggle is in the unlocked position (OFF position), the fitter who removes the release block is subject to the danger of coming into contact with live parts. Such a defect may be caused, for example, by the welding of the switching contents.
SUMMARY OF THE INVENTION
The present invention is based on an object, for example, of refining the switch such that inadvertent contact with live parts during fitting and removal of the release block is safely precluded.
According to the invention, these and other objects are achieved in that the switch includes a member which reflects the actual switch position of the switching contact arrangement. Further, the locking element preferably includes a second operating surface, which is associated with this member and via which the locking element is fixed in its locked position when the member reflects the closed switch position of the switching contact arrangement.
Such a refinement ensures that the locking element can be moved from its locked position to its unlocked position only when the switching contact arrangement is actually open. This is the only time when the release block can be removed from the switch.
In a further refinement of the invention, the locking element can advantageously be produced by a design refinement of a locking rod which is generally known, for example, from WO 99/65124 and is guided by means of elongated holes parallel to the front surface of the switch into which the release block is inserted, and which can be moved as a function of the actual switch position of the switching contact arrangement. In this case, this locking rod can be fixed in its locked position by means of a stop on a switch position indication, when the switch position indication reflects the closed switch position of the switching contact arrangement. This locking rod allows safety fimctions to be implemented which are intended for protection against incorrect operation. In particular, switch-on prevention can be activated as a consequence of the movement of the locking rod into its unlocked position. Furthermore, a device for insertion and removal of the switch relative to a push-in rack can be blocked and/or closing of the switch can be prevented when the switching contact arrangement is closed or the switch is ready to be switched on. This ensures compliance with essential conditions which are applicable, for example, for what are referred to as “main” switches.
The further refinement of this locking rod which can be provided for the purposes of the invention, provides for the locking rod to have a hook-like projection in order to form the first operating surface, with this first operating surface running parallel to the movement direction of the locking rod. In conjunction with this refinement of the locking rod, it is expedient to provide a tab on the release block, which tab is at right angles to the release block installation direction and behind which the hook-like projection of the locking rod can engage. In this way, it is possible to associate the locking mechanism of the switch with the release block at the side, without having to modify the switch in the region of the release block.
A further refinement of the new locking mechanism provides for the locking rod to have a third operating surface, via which the locking rod can be locked in its unlocked position by means of an interlock element. Such a refinement makes it easier to remove and fit the release block, since the locking rod need not be held in its unlocked position by the fitter. If switch-on prevention is active as a result of the locking rod being in the unlocked position, then the switch cannot be switched on when the locking rod is interlocked in such a manner. In this case, the third operating surface can run at right angles to the movement direction of the locking rod, and the interlock element can be in the form of a spring-loaded catch which rests against the fitted release block, can be supported against the locking rod even when the release block is being detached from the switch, and can be latched into the movement path of the third operating surface when the locking rod is being moved to its unlocked position. Such a refinement ensures that the locking rod can be moved freely when the release block is fitted firmly on the switch.
Further, the scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 4769739 (1988-09-01), De Bruin
patent: 4806710 (1989-02-01), Kalvaitis et al.
patent: 5945648 (1999-08-01), M'Sadoques
patent: 6144002 (2000-11-01), Coudert et al.
patent: 6252186 (2001-06-01), Liebetruth et al.
patent: A1-3642719 (1988-06-01), None
patent: A1-19826200 (1999-12-01), None
patent: A2-9965124 (1999-12-01), None
Festlegungen, Deutsche Elektrotechnische Kommission im DIN und VDE (DKE), p. 7 Feb. 1986.
Dahl Joerg-Uwe
Liebetruth Marc
Friedhofer Michael
Harness & Dickey & Pierce P.L.C.
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