EP-4371137-B1 - SWITCH FOR DISCONNECTING AN ELECTRICAL CIRCUIT

EP4371137B1EP 4371137 B1EP4371137 B1EP 4371137B1EP-4371137-B1

Inventors

MUJAWAR, ASAD
BEDNARSKI, Krzystof Ryszard
BURKETT, Roger

Dates

Publication Date: 20260506
Application Date: 20220711

Claims (15)

A switch (100) comprising: a first cam (106) engageable by a user and axially rotatable around a first axis by an operating angle between an on position and an off position; a second cam (102) contacting the first cam, wherein: rotation of the first cam causes rotation of the second cam around the first axis, and the second cam comprises an axial cam portion and a transverse cam portion, the transverse cam portion comprising a protrusion (120) extending along a direction perpendicular to the first axis and two detents (122) arranged symmetrically either side of the protrusion, and one or more biasing members (112) configured to exert a force on the transverse cam portion of the second cam, the axial cam portion (108) is configured, upon rotation of the second cam by the first cam and/or a rotation of the second cam in response to the force exerted by the one or more biasing members, to cause opening and closing of a current conduction path through the switch, characterized in that the two detents (122) are arranged at an oblique angle Θ with respect to each other.
The switch of claim 1, further comprising a cam follower (110) coupled to the one or more biasing members, wherein a toggle point of the switch occurs when the protrusion of the transverse cam portion aligns with an opposing protrusion of the cam follower, optionally wherein the one or more biasing members comprise one or more springs.
The switch of claim 2, wherein rotation of the second cam towards the toggle point is caused by a user rotation of the first cam, and wherein said user rotation of the first cam causes the transverse cam portion to compress the one or more biasing members, wherein maximum compression of the one or more biasing members occurs at the toggle point.
The switch of claim 2 or claim 3, wherein the one or more biasing members are configured to act on the transverse cam portion after the toggle point to cause independent rotation of the second cam, wherein the independent rotation of the second cam occurs until the protrusion of the cam follower aligns with and is received by one of the two detents of the transverse cam portion.
The switch of any preceding claim, wherein the oblique angle between the two detents is between 105 degrees and 130 degrees, optionally wherein the oblique angle is between 105 and 120 degrees, optionally wherein the oblique angle is 110 degrees.
The switch of any preceding claim, wherein the second cam has a second protrusion (120) arranged opposite the first protrusion, and a further two detents (122) arranged symmetrically either side of the second protrusion, wherein the further two detents are arranged at the oblique angle with respect to each other.
The switch of any preceding claim, wherein the protrusion of the transverse cam portion of the second cam is arranged at the end of one or more convexly shaped regions of the transverse cam portion.
The switch of any preceding claim, wherein there is a first rotational offset, α , between the rotation of the second cam relative to the rotation of the first cam around the first axis.
The switch of claim 8, further comprising a bridge cam contacting the axial cam portion of the second cam, wherein rotation of the axial cam portion of the second cam causes rotation of the bridge cam around the first axis, and wherein the rotation of the bridge cam is configured to open and close the current conduction path through the switch.
The switch of claim 9, wherein rotation of the axial cam portion of the second cam causes rotation of the bridge cam around the first axis after a second rotational offset, β .
The switch of claim 9, further comprising a bridge that is axially displaceable along the first axis in response to rotation of the bridge cam, wherein the bridge comprises one or more moveable contacts, and optionally wherein the bridge cam comprises a cam surface comprising two adjacent helical portions, the two helical portions having different slopes, wherein the bridge is configured to follow the cam surface of the bridge cam.
The switch of claim 11, further comprising one or more fixed contacts, wherein the bridge is configured to bring the one or more moveable contacts into contact with the one or more fixed contacts of the switch, when the first cam is in the on position, to close the current conduction path.
The switch of any of claims 9 to 12, wherein an angle of the second rotational offset is configured to be half the oblique angle, β= θ / 2 and/or wherein an angle of the first rotational offset α = ( θ / 2 - (operating angle - θ / 2 ), and optionally, wherein the operating angle is 90 degrees, and optionally wherein the angle of the first rotational offset α is between 10 degrees and 30 degrees, optionally wherein the angle is between 15 degrees and 25 degrees, and optionally wherein the angle is 20 degrees, and/or wherein the angle of the second rotational offset is between 45 degrees and 65 degrees, optionally wherein the angle is between 50 degrees and 60 degrees, and optionally wherein the angle is 55 degrees.
A system comprising: the switch of any preceding claim; and an electrical circuit configured to be electrically coupled to one or more fixed contacts of the switch.
A method for operating a switch of any of claims 1 to 13 to open and close a current conduction path, the method comprising: rotating, by a user, the first cam around the first axis by at least the operating angle; in response to the rotation of the first cam, rotating the second cam which contacts the first cam around the first axis; exerting a force on the transverse cpam portion of the second cam by the one or more biasing members; and causing, by rotation of the second cam by the first cam and/or a rotation of the second cam in response to the force exerted by the one or more biasing members, the axial cam portion to open or close the current conduction path through the switch.

Description

Field This relates to a switch for disconnecting an electrical circuit. In particular, this relates to a switch for disconnecting an electrical circuit with a manual independent make and break mechanism. Background Manual switches can be either independent of a user input (i.e. the user has no control over the movement during the actual switching operation) or dependent, where the speed of the switching operation is controlled entirely by user input with no lag or independent motion (i.e. the speed of making/breaking the circuit mirrors the speed of actuation by the user). Other switches may be semi-independent, where part of the movement of the switching components is controlled by a user then there is a sudden, uncontrolled, switching operation. Typically, manual independent switches can provide rapid make and break operations, and semi-independent switches can provide either a rapid make or a rapid break operation, depending on the design of the device. However, since the actual make/break operation of a manual independent switch is completely independent of user control, the operation is quicker than with a semi-independent switch. This is important at high current applications, where rapid opening of a conduction path can be necessary to reduce or minimise arcing within the device. For this reason, semi-independent devices, which are often simpler and more compact than manual independent devices, are typically only used for lower current applications. There is a need for a simpler and smaller switch with manual independent operation for use at all current ratings, and which has a reduced manufacturing/assembly cost and complexity as compared to other known manual independent switch mechanisms. US4713498 discloses a switch gear which includes a housing have first and second sides and a third side therebetween, at least one main contact bridge in the housing displaceable between two ON-OFF switch position, a spindle rotatable by a handle and carrying a body having a cam slot receiving a cam follower of a contact bridge holder, the contact bridge holder carrying contacts for effecting the two switch positions with associated pairs of fixed contact rails carried by the housing. A snap-in device or collar includes a central body having four peripherally equidistantly spaced niches or recesses. Two mutually opposite/opposing sliders are mounted in the housing in opposed relationship to the rotating body and each slider includes a boss or nose which is designed to enter selected ones of the recesses. Summary Provided herein is a switch for disconnecting or connecting an electrical circuit and a method of operating said switch. The switch comprises a first cam engageable by a user and axially rotatable around a first axis by an operating angle between an on position and an off position. The switch further comprises a second cam contacting the first cam, wherein rotation of the first cam causes rotation of the second cam around the first axis. The second cam comprises an axial cam portion and a transverse cam portion, the transverse cam portion comprising a protrusion extending along a direction perpendicular to the first axis and two detents arranged symmetrically either side of the protrusion, wherein the two detents are arranged at an oblique angle, θ, with respect to each other. The switch further comprises one or more biasing members configured to exert a force on the transverse cam portion of the second cam. The axial cam portion is configured, upon rotation of the second cam by the first cam and/or a rotation of the second cam in response to the force exerted by the one or more biasing members, to cause opening and closing of a current conduction path through the switch. In this way, the electrical circuit is disconnected or connected. The method of operating the switch to open and close a current conduction path comprises rotating, by a user, the first cam around the first axis by at least the operating angle. The rotation may be by direct or indirect engagement of the first cam. In response in response to the rotation of the first cam, the method further comprises rotating the second cam which contacts the first cam around the first axis. The method further comprises exerting a force on the transverse cam portion of the second cam by the one or more biasing members. The method further comprises causing, by rotation of the second cam by the first cam and/or a rotation of the second cam in response to the force exerted by the one or more biasing members, the axial cam portion to open or close the current conduction path through the switch. The opening and closing of the current conduction path can be by transverse motion of one or more components, such as a bridge, or by any other suitable means. Optionally, the switch further comprises a cam follower coupled to the one or more biasing members, wherein a toggle point of the switch occurs when the protrusion of the transverse cam portion aligns with an op