US2116673A - Switch - Google Patents

Description

y 1933- E. FISHER ET AL 2,115,673

' SWITCH Filed Aug. 12, 1935 2 Sheets-Sheet l 'IIIIIIII 2,116,673 SWITCH 2 Sheets-Sheet 2 E. FISHER ET AL Filed Aug. 12, 1935 May 10,1938.

f V JNVENTORS ATTORNEY.

Patented May 10, 1938 PATENT OFFICE SWITCH Lawrence E. Fisher and William H. Frank, Detroit, Mich.

Application August 12, 1935, Serial No. 35,732

7 Claims.

This application relates to switches.

The principal object of the present invention is to provide, in electrical switches, are suppressing means of novel operation and construction. The arc suppressing means here shown is in the nature of a box-like structure or housing surrounding and carrying a movable switch contact and telescoping over a pair oi stationary switch contacts adapted to be connected to each other through the movable contact, and functions to exhaust the air around the contacts and thus smother the arc in the exhausted air space within the box on the action of withdrawing the movable contact. In addition, the walls oi the box support and guide'the movable contact as it moves between the stationary contacts of the switch, and also insulate the movable contact irom the switch actuator or handle.

The box-like structure is preferably of a carbonaceous or fibrous insulating material so that ii there arises, on arcing. any vaporization of the walls of the box-like structure, there will be formed carbon dioxide, and since this gas will not support combustion, such vaporization is no great disadvantage.

'flie box is formed with a central partition dividing it into cells in each oi which is received a stationary contact and the central partition carries the movable contact; thus, on switch opening, any are that occurs will be divided and relatively isolated in the cells by-the central partition and such division oi the arc and such isolation minimizes the disadvantages attendant upon arcing.

The box is formed to fit closely around the stationary contacts and may well be considered as a movable cylinder sliding on a stationary piston; the cylinder-piston action is such that arcing incident to switch opening creates a rapidly expanding gas which tends to accelerate the separation of the cylinder from the piston or, in other words, tends to accelerate switch break.

The fibrous box parts slide along the stationary contacts and since these are oi metal (copper preferred), no undue friction exists as might possibly be the case in the event the fibrous box parts were mounted toslide along fibrous mountings or the like of the stationary contacts. The coefficient oi friction in the case of fiber-copper is much less than that in thecase oi fiber-fiber.

Because oi the long, close fit, bearing of the cell walls on the free ends of the stationary contacts in the cells, the stationary contacts serve as guides and mounts for the housing. Because the box fits closely around the stationary contacts, the cells thereof, when the switch is on, are substantially completely filled by the stationary contacts; thus, on movement of the box from the stationary contacts, the cell volumes are expanded to a tremendous extent thereby g rarii'ying the cells considerably.

Still further-advantages of the present invention willbe best understood upon reference to the following detailed descriptive matter and to the appended drawings, whose Figs. 1 and 2 show parts in circuit ruptured and circuit established position;

Figs. 3 and 4 are end views of the movable and stationary parts of the switch;

Fig. 5, shows a. modification wherein the movable contact includes a part insertable between the stationary contacts and a part adapted to embrace the stationary contacts;

Figs. 6 and 7 show another modification;

Figs. 8 and 9 show a switch whose arrangement I :if contacts diifers from that of Figs. 1-7 inclu- Referring to Figs. 1-4 of the drawings it will be seen that the switch there shown includes a base Ill upon which are mounted stationary contacts i i (of copper or the like) adapted to be connected to line and load respectively through conductors whose terminals are secured andconnected by the connectors i2. For cooperation with and for bridging the gap between the stationary contacts .0 there is provided a movable contact I in the form of a copper slug carried by a blade It 01' fibrous and carbonaceous insulation, the blade being part of a box-like structure comprising a plate It, an actuator handle i1, exterior portions ll spaced from the blade ii to define cells I! receiving the fingers of the stationary contacts, and edge portions 20 whichconnect the blade II and the exterior portions ill at the edges of the same so to close the cells l9 at their edges.

It is observed that reciprocation oi the movable parts establishes or ruptures the circuit and that the extreme limits of movement of the movable parts with respect to the stationary parts I are such that the fingers of the stationary contacts are at all times closely surrounded by portions of the box-like structure. Withdrawal of the blade and the box-like structure partially exhausts the air within the box-like structure and so thus suppresses the arc formed by withdrawal of contact I4 from between the stationary contacts.

It is also observed that portions of the box-like structure mount the movable contact I and guide the latter in its switching movement, and ll also physically connect it to but electrically separate it from the actuator handle I1.

It is also observed that any arc that occurs on switch withdrawal will be divided and the divisions isolated by the cell forming partition or blade IS.

The box, with its blade, is so dimensioned that the cells l9 closely fit the fingers of the stationary contacts; accordingly, gases generated by arcing incident to switch withdrawal will tend to separate the box (cylinder) from the fingers (piston) and thus will tend to accelerate switch withdrawal.

Though the fit between the fibrous walls of cells I! and the fingers is a close fit, no undue friction will be created to impede switching action, for the coeflicient of friction mtween fiber and copper (or the like) is not excessive.

For limiting withdrawal movement of the movable parts from the stationary parts and for supplementing the stationary contacts in their function of supporting and guiding the movable parts in their switching movement, there are provided guides 2| received within notches 22 of the plate l6 and formed with restraining lugs 23.

If desired, the box-like structure may be made of laminae, rather than monolithic, substantially as shown in Fig. 5, and if desired an auxiliary contact 24 may be provided to embrace the fingers of the stationary contacts and electrically connect them in a path parallel to the path through the slug I l. As shown, the tips of the contact 24 may project beyond the edges of the slug H, in the manner of arc-tips, so that these tips engage the stationary contacts before and leave the same after the slug l4 has engaged or left the stationary contacts.

Figs. 6 and '7 show how the portions l8 may be of sheet fiber, formed or shaped as shown.

Figs. 8 and 9 show how the stationary contacts 29 may be staggered to increase the gap between contacts being carried by an insulation block formed to provide a portion 3| which separates the stationary contacts. In such case, the contact 30 may be made longer than the contact 30a so that it will make before and break after the contact 30a does, in order to approximate the arc-tip function performed by the contacts 24 of Fig. 5.

What is claimed is:

1. In a switch, the combination of two rigidly mounted, inflexible, sturdy, relatively insulated adjacent parallel stationary contacts having free ends, one of the contacts being permanently connected to an energized line so as to be normally live, a housing of insulation'comprising two adjacent parallel insulation cells disposed over and capping the free ends of the stationary contacts, the housing'thus being mounted by the stationary contacts for reciprocation along them, each cell containing a contact for making with a stationary contact, means within the housing for interconnecting the cell contacts so as to connect the stationary contacts to each other when the cell contacts make with the stationary contacts, the walls of the cells, all the way from the cell contacts to the free ends of the adjacent stationary contacts, measured when the cell contacts do not make with and are remote from the stationary contacts, being formed to fit and surround closely the stationary contacts so that the stationary contacts will provide a long, close fitting, and accurate mounting and guide for the housing in its reciprocation, and means. outside of and connected to the housing for causing its reciprocation and being insulated from the cell contacts and the stationary contacts by the housing itself, the cell volume, when the switch is closed, being substantially completely filled by the stationary contacts, means for preventing, complete withdrawal of the movable housing from the stationary contacts and designed to permit sufficient withdrawal thereof to enable the movable contacts to leave the stationary contacts and to enable the free space in the cells to be expanded to a considerable extent for rarification thereof, and to insure the stationary contacts closing the cells at all times, the fit between the stationary contacts and the cell walls being so close and their relative proportions being so similar that during cell withdrawal no substantial infiltration of air into the cell arises to minimize the rarification that occurs on such withdrawal.

2. In a switch, the combination of two rigidly mounted, inflexible, sturdy, relatively insulated adjacent parallel stationary contacts having free ends, one of the contacts being permanently connected to an energized line so as to be normally live, a housing of insulation comprising two adjacent parallel insulation cells disposed over and capping the free ends of the stationary contacts, the housing thus being mounted by the stationary contacts for reciprocation along them, each cell containing a contact for making with a stationary contact, means within the housing for interconnecting the cell contacts so as to connect the stationary contacts to each other when the cell contacts make with the stationary contacts, the walls of the cells, all the way from the cell contacts to the free ends of the adjacent stationary contacts, measured when the cell contacts do not make with and are remote from the stationary contacts, being formed to fit and surround closely the stationary contacts so that the stationary contacts will provide a long, close fitting, and accurate mounting and guide for the housing in its reciprocation, and means outside of and connected to the housing for causing its reciprocation and being insulated from the cell contacts and the stationary contacts by the housing itself, the cell volume, when the switch is closed, being substantially completely filled by the stationary contacts, means for preventing complete withdrawal of the movable housing from the stationary contacts and designed to permit sufficient withdrawal thereof to enable the movable contacts to leave the stationary contacts and to enable the free space in the cells to be expanded to a considerable extent for rarification thereof, and to insure the stationary contacts closing the cells at all times, the fit between the stationary contacts and the cell walls being so close and their relative proportions being so similar that during cell withdrawal no substantial infiltration of air into the cell arises to minimize the rarification that occurs on such withdrawal, the

cells being so constructed as to be sealed everywhere except for the openings through which pass the stationary contacts, the fit between the cell walls and the stationary contacts in such open- 3. The combination of tworlgidly mounted, in-

allel stationary contacts having free ends, one

' oi the contacts being permanently connected to an energized line so as:to' be normally live, a

housing of insulation comprising two adjacent parallel insulation cellsdisposed over and capping the free ends of the stationary contacts and having acommon separatingwall, the housing thus being mounted by the stationary con"- tacts for reciprocation jalong them, each cell containing a contact for making with a stationarycontact, means within the common separating wall of the housing for interconnecting the cell contacts so as to connect the stationary contacts to each other when the cell contacts make with the stationary contacts, the walls of the cells, all the way from the cell contacts to the free ends of the adjacent stationary con- .tacts, measured when the cell contacts do not make with and are remote from the stationary contacts, being formed to lit and surround closely the stationary contacts so that the stationary contacts willprovide a long, close fitting, and accurate mounting and guide for the housing in its reciprocation, and means'outside of and connected to the housing for causing its reciprocation and being insulated from the cell contacts and the stationary contacts by the housing itself, the cell volume, when the switch is closed, being substantially completely filled by the stationary contacts, the fit between the stationary contacts and the cell walls being so close and their relative proportions being so similar that during cell withdrawal no substantial infiltration of air into the cell arises to minimize the rarification that occurs on such withdrawal. t

4. The combination of two rigidly mounted, inflexible, sturdy, relatively insulated adjacent parallel stationary contacts having free ends, one of the contacts being permanently connected to an energized line so as to be normally live, a housing of insulation comprising two adjacent parallel insulation cells disposed over and capping the i'ree ends of the stationary contacts and having a common separating wall, the housing thus being mounted by the stationary contacts for reciprocation along them, each cell containing a contact for making with a stationary contact, means within the common separating wall of the housing for, interconnecting the cell con- 7 tacts so as to connect the stationary contacts to each other when the cell contacts make with the stationary contacts, the walls of the cells, all the way from the cell contacts to the free ends of the adjacent stationary contacts, measured when the cell contacts do not make with and are remote from the stationary contacts, being formed to fit and surround closely the stationary contacts so that the stationary contacts will provide a long, close fitting, and accurate mounting and guide for the housing in its reciprocation, and means outside of and connected to the housing for causing its reciprocation and being insulated from the cell contacts and the stationary contacts by the housing itself, the cell volume, when the switch is closed, being substantially completely filled by the stationary contacts, the fit between the stationary contacts and the cell walls being so close and their relative proportions being so similar that during cell withdrawal no substantial infiltration of air into the cell arises to minimize the rarification that occurs on such withdrawal, the cells being so constructed as to be sealed everywhere except for the openings through which pass the stationary contacts, the fit between the cell walls and the stationary contacts in such openings being so tight that the stationary contacts seal the cells, whereby withdrawal of the housing from the stationary contacts for causing separation of the cell contacts from the stationary contacts is accompanied by a rariflcation of the atmosphere within the cells. i

5.' In a switch, a base, two stationary contacts mounted thereon and permanently connected to circuit lines, with one of them being permanently live, both having adjacent parallel free ends, a

movable contact for engaging the free ends of the stationary contacts and thus bridging them, means manipulable for reciprocating said movable contact towards and away from the stationary contacts, and a single means for operativ ly connecting the movable contact to the manipulable means whereby movement of the latter will cause movement oi the former and for supporting and guiding the movable contact in its movement and for constantly shielding and enclosing the movable contact and for constantly shielding and enclosing the free ends of the stationary contacts'and for providing an enclodng housing around the contacts during their separation comprising a unitary housing structure having two hollow solid walled cells of insulating material in the interior of each 01' which is a part of the movable contact, each hollow cell being sealed throughout except at one open end in which is permanently disposed the free end of one of the stationary contacts, the transverse cross sectional area oi each cell interior, measured all the way from end to end of the cell, being very closely dimensioned to that of the free end of the stationary contact therewithin so that the latter provides a bearing and guide for the cell in its movement, the manipulable means being outside of and connected to the housing, and means for limiting movement of the movable contact away from the stationary contacts to an extent insuificient to permit the cells ever to leave the stationary contacts and thus expose the latter or uncouple the cells and the stationary contacts, the free ends of the stationary contacts being relatively close to each other, sufllciently to provide a magnetic path between them, and the cells oi the housing having a common separating wall which is proportioned to slide between the free ends of the stationary contacts and in which common separating wall is disposed the movable contact.

6. In a switch, a base, two stationary contacts mounted thereon and permanently connected to circuit lines, with one of them being permanently live, both having adjacent parallel free ends, a movable contact for engaging the free ends of the stationary contacts and thus bridging them, means manipulable for reciprocating said movable contact towards and away from the stationary contacts, and a single means for operatively connecting the movable contact to the manipulable means whereby movement of the latter will cause movement of the former and for supporting and guiding the movable contact in its movement and for constantly shielding and enclosing the movable contact and for constantly shielding and enclosing the free ends of the stationary contacts and for providing an enclosing housing'around the contacts during their separation comprising a unitary housing structure having two hollow solid walled cells of insulating material in the interior of each of which is a part of the movable contact, each hollow cell being sealed throughout except at one open end in which is permanently disposed the free end of one of the stationary contacts, the transverse cross sectional area of each cell interior,-measured all the way from end to end of the cell, being very closely dimensioned to that of the free end of the stationary contact therewithin sothat the latter provides a bearing and guide for the cell in its movement, the manipulable means being outside 01' and connected to the housing, and means for limiting movement of the movable contact away from the stationary contacts to an extent insufflcient to permit the cells ever to leave the stationary contacts and thus expose the latter or uncouple the cells and the stationary contacts, each cell volume being so dimensioned to that of that part of the stationary contact therewithln when the switch is closed that each cell interior is substantially completely filled by a stationary contact whereby movement of the housing away from the base causes a tremendous increase in the free volume of each cell interior, the free ends of the stationary contacts being relatively close to each other, sufficiently to provide a magnetic path between them, and the cells of the housing having a common separating wall which is proportioned to slide between the free ends of the stationary contacts and in which common separating wall is disposed the movable contact.

7. In a switch, the combination of a prong, an insulation cell telescopically disposed over and capping the free end of the prong, the cell and prong being mounted for relative telescopic reciprocation, the cell containing a contact for making with the prong and being closed throughout except forone open end adapted to be closed by the prong, the wall of the cell, all the way from the cell contact to the free end of the prong, measured when the cell contact does not make with and is most remote from the prong, being formed to fit and surround closely the prong so that the prong and cell will provide a long, close fitting and accurate mounting and guide for the prong and cell in their relative reciprocation, the cell volume, when the switch is .closed, being substantially completely filled by the prong, means for preventing complete withdrawal of the cell and prong relatively and designed to permit relative withdrawal to an extent sufllcient to permit the cell contact to be separated from the prong and to enable the free space in the cell to be expanded to a considerable extent for rarificatlon thereof and to insure the prong closing the cell at all times, the fit between the prong and the cell wall being so close and their relative proportions being so similar that during cell withdrawal no substantial infiltration of air into the cell arises to minimize the rarification that occurs on such withdrawal, the cell being so constructed as to be sealed everywhere except for the opening through which passes the prong, the fit between the cell wall and the prong in such opening being so tight that the prong seals the cell, whereby withdrawal of the cell from the prong for causing separation of the cell contact from the prong is accompanied by a rarification of the atmosphere within the cell.

LAWRENCE E. FISHER.

WILLIAM H. FRANK.

Images