US2310918A - Enclosed switch - Google Patents

Description

Filed July 29, 1940 3 Sheets-$heet l +9 7 ssfifii 34 /3 28 f; [AWE/V701? y 2 F redericK 8. Adam A Tram/5r F. B. ADAM ENCLOSED SWITCH Filed July 29, 1940 Feb. 16, 1943.

3 Sheets-Sheet 2 Freder/cK 5. Adam BY a? 7 4% 6 T. O NE Feb. 16, 1943. F. B. ADAM 2,310,918

ENCLOSED SWITCH Filed July 29, 1940 3 Sheets-Sham. 3

g V v INVENTOR F redericK 5. Adam a A o-4% 7' DRIVE) Patented Feb. 16, 1943 ENCLOSED SWITCH Frederick B. Adam, St.

or to Frank Adam E Louis County, Mo., assignlectrio Company, St. Louis,

Mo., a corporation of Missouri Application July 29, 1940, Serial No. 348,092 11 Claims. (01. 200-114) This invention relates to improvements in Y enclosed switches. More particularly the invention relates to improvements in switches wherein stationary contact blades are bridged by a contactor that is positioned in a shuttle of insulating material.

It is an object of the present invention to provide an improved enclosed switch of simple and compact construction which is efllcient in operation.

The switch of my invention is particularly adaptable for fused switches since the fuses may be mounted on top of the switch-operating mechanism. Such construction makes it possihle to considerably reduce the size of the enclosing cabinets or boxes.

Switches have been made that enclose the circuit-making contactor in a housing of insulating material, but the assembly and construction of these housings has been expensive and lasting positive contact has not been achieved. It is poswith the'present invention to use a shuttle of insulating material which has no positive connection with the elements contained therein. By use of this type of shuttle, the time required to assemble the switch will be materially short ened. The present invention also provides forthe use of spring means to clamp the contacting electrical parts together to insure trouble free contacts over a long period of usage.

'Other objects and advantages of the invention will become apparent from the drawings and the accompanying description.

A preferred form of the invention isshown and described in the drawings and the accompanying description, but it is to be understood that the drawings and accompanying description do not limit the scope of the invention which is defined by the appended claims.

In the drawings, Fig. 1 is a plan view of a fused switch in an enclosing box.

Fig. 2 is a cross-sectional view of the switchbox and the combination fuse and switch block positioned therein, taken along the plane 22 of Fig. l, and shows the switch in the on position.

switch in the oil' Fig. 4 is a cross-sectional view of the combination fuse and switch block shown in Fig. 1 taken along plane 44 of Fig. 1, and shows the use of an optional form of fuse terminal;

Fig. 4a is a partial cross-sectional view of a consist of two pieces.

switch as shown in Fig. 4 but without provision for fuses.

Fig. 5 is a, cross-sectional view of the switch portion of the combination fuse and switch block taken along plane 5-4 of Fig. 2.

- Fig. 6 is a cross-sectional view of the combinaticn fuse and switch block and enclosing box taken along plane 6-8 of Fig. 2.

Fig. 'i' is a cross-sectional view of the movable housing or shuttle taken along plane 1-! of Fig. 2.

Fig. 8 is a perspective view of the various elements of the shuttle or movable housing.

Fig. 9 is a cross-sectional view of a portion,

of the shuttle or movable housing showing an optional form of auxiliary contact.

Referring to the drawings, I 3 denotes a switch-- box. A combination fuse and switch block that may be positioned in the switch-box is denoted by numeral II. A plate of insulating material I4 may be positioned in the switch-box i3, under the block l5; Mounted on the upper side of block it are fuse terminals. For purposes of iilustration I show two types of fuse terminals. Positioned in a recess in the under side of block I! are two parallel contact blades 24 and 26. In the drawings, the contact blade 26 is shown to This expedient has been found useful in some instances to provide addi tional flexibility, although it is not necessary, and a single blade has been found to operate satisfactorily. Also positioned in the recess in the block I5 is a shuttle 35.

As stated above two types of fuse terminals are shown in the drawings. In Fig. 2 and Fig. 3, fuse clips of the conventional type are shown, while in Figs. 4 and 6, clamps are shown which are described in an application filed May 11, 1936. Serial No. 79,050, in which I am one of the joint inventors. This application has now materialized into Patent No. 2,220,698. The clips 22 and 23 may be secured respectively to terminal 48 and contact blade 24 by suitable means such as a bolt, rivet, or screw. The fuse clips hold a fuse i8 which serves to electrically connect terminal 48 and contact blade 24. In Figs. 4 and 6, extensions 41 and 25 are provided on the parts 48 and 24 respectively to form part of the fuse terminals. The fuse terminals are formed by slots in the ends of the parts 41 and 25, and clamps 20 and 2| that press the slotted ends of the parts or contact blades tightly against the blades of a fuse denoted by numeral it. Such a fuse terminal provides direct engagement between one of the fuse terminals and the terminal 46 and switch by eliminating an the other fuse terminal and the contact blade 24. This direct engagement with the fuse permits an increase in the electrical efficiency of the unnecessary connection between the fuse and the terminal or switch This switch is particularly adaptable to this type of fuse terminal clamp, since the combined switch contact and fuse terminal as illustrated by 24 and 25 may be formed of one piece of metal.

Contact blades 24 and 26 may be supported in one end of the block l and may extend into the recess 49 in the under side thereof. The blades may be inserted in openings in theblock l5 and connected to the block by suitable means, such as screws 28 and 5|. The contact blades 24 and 26 are shown parallel to and substantially coextensive with each other and separated by insulators 32 and 34. Contact blades 26 are connected to leads 30. Leads 36 may be connected to the line, and leads 3| to the load. It can be seen by reference to the drawings that bridging of the contact blades 24 and 26 will close the switch.

In the drawings the contact blades 24 and 26 are shown bridged by contactors ,38 and 42. These contactors are mounted in a shuttle or housing 35 of insulating material that moves back and forth in a recess in the under side of block 15. The movement of shuttle 35 moves contactors 38 and 42 into and out of engagement with contact blades 24 and 26, thereby closing and opening the circuit. Contactor 36 may be termed an auxiliary contactor, and contactor 42, the main contactor. The contactors 38 and 42 are so arranged that auxiliary contactor 38 engages contact blades 24 and 26 before, and disengages contact blades 24 and 26 after the main contactor 42. Such an arrangement definitely prevents any electrical arcing when main contactor 42 disengages contact blades 24 and 26, since the current will continue to flow through the auxiliary contactor. Some arcing may occur when the auxiliary contactor 38 disengages the contact blades, but are tips are provided for the auxiliary contactor to prevent burning. In the drawings, the main contactor 42 is shown as a metallic roller that engages the inner faces of contact blades 24 and 26, while the auxiliary contactor is a U-shaped metallic clip that engages the outer faces of the contact blades. It can be seen, therefore, that while any arcing between the auxiliary contactor 38 and contact blades 24 and 26 may burn the outer faces of the contact blades. it cannot burn the inner faces of the blades which engage the main contactor 42. Such an arrangement insures an electrically efficient connection between the main contactor and the contact blades during the life of the switch.

The auxiliary contactor 36, is preferably made of steel. One of the functions of the auxiliary contactor 38 is to provide pressure between the contact blades and the main contactor 42. A copper contactor would be unsatisfactory for th s purpose, because copper is susceptible to fatigue. A copper contactor would permit a derrease in contact pressure and a decrease in electrical efficiency after a period of time. the fatigue of the metal was excessive. arc n might occur at the main contactor, and this would greatl decrease the efficiency and value of the switch. Another function of the auxiliary contactor is to reduce the flow of current through the switch immediately prior to the moment when the circuit is broken. Such a reduction in the amount of current flowing through the switch limits the intensity of the arc. Since steel is not as good a conductor as copper, the use of an auxiliary contactor of steel serves to reduce the current immediately prior to the opening of the switch. It should be noted that both the main and auxiliary contactors provide a double break for the circuit and thus reduce the intensity of any are formed.

The shuttle 35 in which contactors 38 and 42 are supported, consists of two sections 36 and 31 which enclose contactors 36 and 42 and insulator 34. It serves as the supporting means for the three elements. The two sections of the shuttle are preferably duplicates and may be molded of a suitable insulating material, since such construction reduces the cost of manmacture. Each section has a number of recesses molded therein which 'cooperate to hold the elements carried by the shuttle without a connection between the shuttle and the elements. Such an arrangement reduces the cost of manufacture by facilitating rapid assembly of the shuttle. To assemble the shuttle, the contactors 36 and 42 and the insulator are merely positioned in one section, and the other section is secured to the first by a suitable means, such as a nut and bolt or rivet.

Each section may be provided with a recess 54, a larger recess 43, and a transverse slot 44. The slot 44 is designed to receive bail H or other form of actuator. When the two sections of the shuttle are assembled in operative relation, the ball. I i is enclosed and held by the slots 44. The ball H has a handle portion it which may be manually operated to move the bail and shuttle have an arcuate section and a flat plane section and is designed to receive auxiliary contactor 38. The flat plane section of the recess extends above the arcuate section and receives the ends of the auxiliary contactor 36, thereby retaining the contactor in position. The plane sections of recess 43 may be tapered to form an enlarged or flared opening in the end of the shuttle to facilitate its assembly on the contacts 24 and 26. The recess 54 may also be provided with a flat and arcuate section. The arcuate section may be formed to receive the main contactor 42, and the flat section may be designed to receive the insulator 34 as indicated in Fig. '1. The large portion of the insulator 34 engages the flat section of the recess 54 and may be held in position by the ends of the recess and by contactor 42. The contactor in turn is held in position by the ends of the arcuate section of recess 54 and by the insulator Insulator 34 may be designed so that it may be removably supported in the shuttle 36. Such an arrangement permits the use of one type of insulation for the shuttle and a different type of insulation for insulator 34. The insulation used in the halves of shuttle 35 is preferably a less brittle material than that used in insulator 34. Although'any insulating material may be used for insulator 34, I have found that Lava" is highly satisfactory. The insulator 34 may be provided :with a number of transverse corrugations which serve to prevent surface fiashovers caused by a coating of metal from the contacts forming on the insulator.

The sections of the shuttle 35 may be made long enough to enclose the ends of the contact blades 24 and 26 at all times.

As the handle I8 is moved to the "on position, the shuttle 35 moves toward the contact blades 24 and 26. The insulator 34 moves between the contact blades 24 and 28 and cooperates with stationary insulator 32 to insulate the contact blades 24 and 26 from each other.

As the shuttle 35 continues to move into the on position, the auxiliary contactor 38 is brought into contact with contact blades 24 and 26 to close the circuit. As the shuttle 35 continues to move into the on position, the tapcred ends of the contact blades and the tips of the auxiliary contactor 38 cooperate to bend contact blades 24 and 28 toward each other. The auxiliary contactor 38 is so dimensioned that it forces the blades 24 and 28 to bend toward each other until the distance separating them is less than the diameter of main contactor 42. As the shuttle 35 continues to move to the closed circuit position, the main contactor 42 is brought into engagement with the contact blades 24 and 28 and is forced between them. The movement of main contactor 42 between the contact blades 24 and 26 causes them to move outwardly in opposition to the force exerted by auxiliary contactor 38. This force is considerable since the auxiliary contactor is preferably made of steel, and this force insures intimate contact between the main contactor 42 and the contact blades 24 and 28. In addition, the current has a shorter path through the main contactor 42. When the handle is moved toward the position, the shuttle 35 moves toward the off position, the main contactor 42 is moved out of engagement with contact blades 24 and 26, and insulator 34 is moved between the ends of contact blades 24 and 26. No arcing occurs when the main contactor 42 moves out of engagement with the contact blades 24 and 26, because the circuit is still completed through auxiliary contactor 38. This contactor is made of steel and serves to reduce the amount of current flowing through the circuit immediately prior to the moment when the circuit is broken by disengagement between the contact blades and auxiliary contactor 38. As the shuttle 35 continues to move into the of! position, the auxiliary contactor 38 is moved out of engagement with the contact blades 24 and 26 and the circuit is broken. The electrical arc will form between the are tips 48 on auxiliary contactor 38 and theputer faces of contact blades 24 and 26. The presence of the movable insulator between the contact blades 24y and 28 prevents an are from forming between; -the contact blades, and the continued movement of shuttle 35 to the open circultposition increases the distance between the contactor 38 and the blades 24 and 28, and serves to quench the arc. Such an arrangement keeps the main contactor 42 and the inner faces of contact blades 24 and 2'3 free from the destructive effects of arcirg. This insures good electrical contact between the main contactor 42 and contact blades 24 and 28 at all times.

The drawings show an optional form of auxiliary contactor in Fig. 9. In this form of auxiliary contactor, the necessary resiliency is provided by a steel clip 33 positioned around a U- shaped contactor of copper. This form of auxiliary contactor has less electrical resistance than the other form shown in the drawings and might be desirable in some cases.

The main contactor 42 shown in the drawings is a cylinder or roller of a metallic conductor such as copper, and is rather loosely supported by shuttle 35. Such an arrangement permits the main contactor 42 to r te. The rotation of the contactor avoids excessive wear and insures efflcient electrical contact in the switch during its entire life.

While I have shown a particular type of em closing box for the switch and actuating mechanism for theshuttle for purposes of illustration, it is obvious that various types of enclosures and actuating mechanisms may be used.

In Fig. 4a I show an unfused form of my switch in which lead 3| is secured by means of 8. lug directly to the top of contact 24 as shown. The other parts of the switch remain unchanged.

It can beseen from the foregoing paragraphs that, by use of the invention, an enclosed switch of compact construction may be had that will be efficient in operation.

While the foregoing description has covered in detail certain preferred embodiments of the invention, it is to be understood that the device may be varied considerably as to the parts shown and their arrangement and combination without departing from the spirit and full intended scope of the invention, as definedby the appended claims.

What I claim is:

1. In an electric switch, a base of insulating material provided with a longitudinally extending recess in the underside thereof, a pair of relatively long fiat contacts secured to the base and extending into the recess, a pair of fuse terminals mounted on the top side of said base and adapted to support an overload protective device, one of said contacts being electrically connected to one of said fuse terminals, a box of insulating material positioned for sliding back and forth in said recess, one end of said box provided with openings therein to allow the contact blades to enter the box, a main contactor sup ported in the box and arranged to engage the inner faces of the contacts when the switch is in the closed circuit position, and a U-shaped pressure contactor supported in said box andarranged to engage the outer surfaces of said contacts and press them against the main contactor when the switch is in the closed circuit position.

2. In an electric switch, a base, a line and load contact blade supported by the base, said line and load contact blades being substantially parallel to and substantially coextensive with each other, a movable insulating member adapted to slide between the contact blades, a main contactor comprising a metallic roller adapted to engage the inner faces of the contact blades, 9. U- shaped pressure contactor adapted to engage the outer faces of the contact blades and thereby force the free ends of the contact blades toward each other and against the main contactor, and a shuttle formed of cooperating sections of insulating material to form a split housing having recesses therein to removably support the main and auxiliary contactors and the movable insulating member.

3. In an electric switch, an insulating base having a recess in the under side thereof, a pair of flat contact blades secured to the base so as to extend into the recess with the plane of the blades parallel to the top of the base, one of said contact blades being adapted to be connected to the line, the other of said contact blades having an end thereof bent to extend perpendicularly above the base to form a portion of a fuse terminal, said contact blades being substantially parallel to and substantially coextensivie with each other, a contactor adapted to engage the contact blades and electrically connect them, a

movable insulating member adapted to slide between the contact blades, and a shuttle in the recess adapted to carry the contactor and insulating member, said shuttle being formed of insulating material.

4. In an electric switch, a base of insulating material provided with a longitudinally extending recess in the underside thereof, a pair of fiat contact blades supported by the base with their principal planes parallel to each other and to the top of the base, said blades being substantially coextensive and extending longitudinally of the recess, a plate removably secured to close the bottom of the recess, a box of insulating material positioned in the recess and guided by the walls of the recess and by the plate for longitudinal movement in the recess, an opening in one end of the box to allow it to move over the ends of the contact blades and thereby enclose the ends of the contact blades and a contactor supported in and by the box and positioned to engage the inneg surfaces of the contact blades when the switch is in the closed circuit position.

5. An electric switch comprising a base, a pair of spaced contact blades supported thereby substantially parallel to and substantially coextensive with each other, a movable insulating member adapted vto slide between the contact blades, a main contactor adapted to engage the inner faces of the contact blades, an auxiliary pressure contactor adapted to engage the outer faces of the contact blades and force the blades against the main contactor, and a shuttle designed to carry the contactors and movable insulating member, said shuttle comprising two formed cooperating sections of insulating material forming a housing that is split along a plane parallel to said contact blades, said sections having recesses therein to removably support the contactors and movable insulating member without additional fastening means.

6. In an electric switch, an insulating base provided with a recess in the under side thereof, a flat line and load contact blade separated from each other and secured to the base so as to extend into the recess, saidiine and load contact blades being substantially parallel to and substantially coextensive with each other and having their principal plane parallel to that of the base, a movable insulating member adapted to slide be-' tween the contact blades, a main contactor comprising a metallic roller adapted to engage the inner faces of the contact blades, a substantially U-shaped pressure contactor adapted to engage the outer faces of the contact blades and thereby force the free ends of the contact blades toward each other, and a of insulating material adapted to slide in the recess in the under side of the insulating base, said box comprising two formed sections designed to cooperate to form a split housing having recesses therein adapted to removably support the main contactor, the pressure contactor, and the movable insulating member, said box being guided by portions of the recess on the under side of the insulating base and fuse terminals mounted at opposite ends of the top side of the insulating base adapted to support an overload protective device.

7. In an electric switch, an insulating base provided with a recess in the under side thereof, a line and load contact blade separated from each other and secured to one end of the base so as to extend into the recess in said base, said line and load contact blades being substantially parallel to and substantially coextensive with each other, a movable insulating member adapted to slide between the contact blades, a main contactor adapted to engage the irmer faces of the contact blades, a pressure contactor adapted to engage the outer faces of the contact blades and thereby forc the free ends of the contact blades toward each other and press the blades against the main contactor, and a box adapted to slide in the recessin the under side of said base, said box comprising a housing of insulating material, and-being adapted to carry the main contactor, the pressure contactor, and the insulating member.

8. In an electric switch, an insulating base provided with a recess extending longitudinally in the under side thereof, a line and load contact blade separated from each other and secured to the base so as to extend longitudinally into the recess in said insulating base, said load and line contact blades being substantially parallel to and substantially coextensive with each other, a movable insulating member adapted to slide between the contact blades, a main contactor comprising a metallic roller adapted to engage the inner faces of the contact blades, asubstantially U -shaped spring member provided with contacts at each end thereof adapted to engage the outer faces of the contact blades and thereby force the free ends of the contact blades toward each other and force the blades against the main contactor, a box adapted to slide in the recess in the under side of the insulating base, said box comprising two formed sections designed to cooperate to form a split housing having recesses therein adapted to removably support the main contactor, the spring member and the movable insulating member, said box being guided by portions of the recess in the under side of the insulating base and fuse terminals mounted at opposite ends of the top side of the insulating base adapted to support an overload protective device, one of said fuse terminals being connected to one of the contact blades.

9. In an electric switch, a base, a line and load contact blade supported by the base and sepa-- rated from each other, said contact blades being substantially parallel to and substantially coextensive with each other, one of said contact blades being flexible, a movable insulating member adapted to slide between the contact blades, a main contactor adapted to engage the inner faces of the contact blades, a U-shaped pressure contactor of steel adapted to engage the outer faces of the contact blades and thereby force the free ends of the contact blades toward each other and press the blades against the main contactor, a shuttle comprising a housing of insulating material having recesses therein to removably support the main contactor, pressure contactor, and the movable insulating member and means to operate the shuttle.

10 Electric switch apparatus comprising a switch box, a combination fuse and switch block of insulating material positioned in said switch box, a recess in the under side of said combination fuse and switch block, a pair of fiat contact blades mounted in one end of said fuse and switch block and extending into the recess in the under I side thereof, said contact blades being substantially parallel to and substantially coextensive with each other and having their principal planes parallel to that of the switch block, a movable insulating member adapted to slide between the contact blades, a main contactor comprising a metallic roller adapted to engage the inner faces of the contact blades, a substantially U-shaped pressure contactor of steel adapted to engage the outer faces of the contact blades and thereby force the free ends of the contact blades toward each other and the blades against the main contactor, a shuttle comprising two formed cooperating sections forming a split housing having recesses therein adapted to removabiy support the main contactor, the pressure contactor, and the movable insulating member, said shuttle being guided by the walls of the recess in the under side of the fuse and switch block, a bail Journaled in the sides of said switch box and engaging a transverse opening in the shuttle so that movement of the bail causes movement of the shuttle, and fuse terminals positioned on the top of the combination fuse and switch block, one of said fuse terminals being connected to one of. the contact blades.

11. In an electric switch, an insulating base, a plurality of adjacent recesses extending longitudinally in the under side of said base, a plurality of cooperating line and load contacts supported by the base, each cooperating line and load contact extending into one of said recesses, said line and load contacts being substantially parallel to and coextensive with each other and having their principal plane parallel with that of the base, a plurality of boxes of insulating material each positioned and guided in one of the recesses for longitudinal sliding movement, each box having recesses in the walls thereof to removably support an insulating member, a main contactor, and a U-shaped pressure contactor, each box being provided with an opening in one end thereof to permit entrance of a line andload contact therein, a main contactor in each box positioned to engage the inner surfaces of the line and load contacts, a pressure contactor in each box positioned to compress the line and load contacts against the main contactor, and means connecting adjoining boxes for simultaneous movemen FREDERICK B. ADAM.

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