Electrical transmission or interconnection systems – Switching systems – Switch actuation
Patent
1997-02-12
1998-07-14
Shoop, Jr., William M.
Electrical transmission or interconnection systems
Switching systems
Switch actuation
307125, 526 39, H01H 300
Patent
active
057809410
DESCRIPTION:
BRIEF SUMMARY
This application is the national phase of international application PCT/F195/00311 filed Jun. 1, 1995 which designated the U.S.
BACKGROUND OF THE INVENTION
This invention relates to a control circuit for manual forced control of a unit, this circuit including a manually operated switch. Forced control refers herein to apparatus and a procedure for use in which the operator may manually activate or correspondingly deactivate a certain unit at a desired moment, and thus bypass, e.g. the automatic control system that normally controls the unit.
A solution is previously known for enabling forced control of a unit in which solution a manual push button-switch is provided along with the unit. In the previously known solution, the push button-switch is of a locking type, so it will remain permanently in another position subsequent to being pushed, simultaneously maintaining forced control active. When the push button-switch is pushed again, will return to its initial position, and the force controlled unit will also return to its initial state.
The most significant drawback of this prior art solution is that the position of the push button-switch must be examined on the basis of a visual estimate when the unit is assembled, so that the forced control will not remain switched on unintentionally. E.g., in systems having a unit backing up another unit, malfunctions may occur in the operation of the unit (the active unit), and, of course the unit will not obey the automatic control system if the push button-switch is in forced control on -position when the unit is assembled. If a unit has a central position in a system, an unintentional on -state of forced control may break down the system. In addition, visual examining requires time, since the operator of the unit must control the position of the push button-switch of each unit one by one. In order to facilitate visual examining, it has been necessary to increase the size of the push button-switch to better distinguish the switch and its position. Due to the larger size, physical placing of the push buttonswitch causes problems.
SUMMARY OF THE INVENTION
The object of this invention is to solve the above-mentioned problem and provide a control circuit for forced control of a unit, in which circuit no visual checks are required when the unit is assembled. This is achieved with a control circuit of the invention, in which the switch is of a non-locking type, and therefore is able to return to its initial position when the manual use directed to it has ended. The the control circuit includes a first switch means having: a first input for receiving the control pulse actuated by the use of the switch; a set input for receiving a predetermined set signal; and an output to which the circuit is responsive, and which is adapted to change its state to a predetermined set state in response to a set signal, and to change its state between the set state and another alternative state in response to a control pulse, and to remain in the same state until the following control pulse or set signal is inputted.
The invention is based on the idea that when forced control is carried out by using a control circuit with no mechanically locking components, the unintentional on-state of forced control may be avoided, and visual examining is not necessary during the initialization of the unit. The most significant advantages of the control circuit of the invention are thus a reduced need for examining, since forced control may automatically be switched off during the initialization, as well as space saving as the push button-switch no longer needs to be large and easily distinguishable. Furthermore, the control circuit of the invention is very inexpensive and small, owing to which it is suited for a variety of applications.
In a preferred embodiment of the control circuit of the invention, a manually operated switch includes a break circuit and a make circuit, and the control circuit includes a second switch means. In this case, the second switch, preferably an SR-type flip-flop, is ada
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patent: 5642104 (1997-06-01), Erwin
Kaplan Jonathan
Nokia Telecommunications Oy
Shoop Jr. William M.
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