US2105455A - Switching device - Google Patents

Description

Jan. 11, 1938. w. GIGER Er AL SWITCHING DEVICE Filed Oct. 18, 1935 5 Sheets-Sheet 1 flu Jan. 11, 1938. w. GIGER ET AL 2,105,455

SWITCHING DEVICE Filed oct. 18, 1955 5 5 sheets-sheet 2 @D ou@ Jzmll, 1938. w. GIGI-:R Er Al.

SWITCHING DEVICE Filed oct. 18, 1955 5 Sheets-Sheet 3 Jan. 11, 1938. w. GIGER Er A1.

SWITGHING DEVICE Filed Oct. 18, 1935 5 Sheets-Sheet 4 Jan. 11, 193s. W, @GER Er AL 2,105,455

SWITGHING DEVICE Filed Oct. 18, 1935 5 Sheets-Sheet 5 3a a7 6 ya f f'. @5X/g5. 6

Patented Jan. 11, 1938 UNITED STATES PATENT OFFICE SWITCHING DEVICE Application October 18, 1935, Serial No. 45,552

l1 Claims.

This invention relates in general to improvements in switching devices, and more particularly to a device operable either as a so-called reverser or changeover switch to change over an electrical system., such as the power system of an electrically driven vehicle, from one operative connection into another operative connection.

Reversers and changeover switches utilized for controlling the connections of the driving motors of an electrically driven vehicle are usually of the pneumatically operated drum type, consisting principally of a large drum arranged for rotation about the axis thereof, such drum carrying contact segments frictionally engaging with fixed contact lingers, and being actuated by two oppositely arranged pneumatic cylinders through a rack and pinion drive. Such construction results in switches of considerable weight requiring a large amount of space, and such switches do not operate satisfactorily at low. ambient temperatures on account of the resistance then offered to movement of the drum by the lubricant required for preventing excessive wear of the Contact segments and of the contact ngers resulting from the frictional engagement thereof.

Such disadvantages are obviated by utilizing a reciprocatory switch operable in two positions thereof to cause abutting engagement of one or of another set of contacts, the switch being preferably operated, through a suitable mechanism, from a rotary shaft driven by the pistons of two coextensive cylinders actuating the shaft through a double rack and pinion drive. The movable contact members of the switch are preferably urged against the associated fixed contact members by resilient means connecting the movable members with the switch base in insulated relation therewith. Such resilient means also cause the switch to be maintained in the one or in the other operative position thereof by opposing the passage of the switch mechanism through one or through another dead center thereof.

It is therefore one of the objects of the present invention to provide a switching device of the character described which shall be compact in construction and light in weight.

Another object of the present invention is to provide a switching device of the reciprocatory double throw type in which cooperating fixed and movable contact members engage by abutment.

Another object of the present invention is to provide a switching device operable by a rotary shaft and maintained in operative position by opposing the movement ofthe mechanism linking the shaft and the switch through a dead center thereof.

Another object of the present invention is to provide a switching device in which the cooperating movable and xed contact members are urged into engagement by resiliently connecting the movable contact member with the base of the switch.

Another object of the present invention is to provide a switching device actuated by the pistons of a pair of coextensive parallel cylinders.

Objects and advantages other than those above described will be apparent from the following description when read in connection with the accompanying drawings, in which:

Fig. 1 is a cross sectional elevation of one embodiment of the present invention taken on line I-I of Fig. 2, in which two movable contact members are actuated by a single eccentric mounted on a drive shaft, a portion of the pneumatic drive of the switch being omitted to simplify the drawings;

Fig. 2 is a front elevation of the embodiment illustrated in Fig. 1 with one of the stationary contact members removed to better disclose the details of the device;

Fig. 3 is a side elevation, partially in cross section, of the pneumatic drive of the device illustrated in Figs. 1 and 2 and of the interlocking contacts controlled thereby;

Fig. 4 is a cross sectional elevation taken on line IV-IV of Fig. 5 of another embodiment of the present invention, in which two movable contact members are actuated by two eccentrics mounted on the drive shaft with the centers thereof in substantially opposite radial planes;

Fig. 5 is a front elevation of the embodiment illustrated in Fig. 4 with one of the stationary contact members anda portion of the associated movable contact member removed to better disclose the details of the device; and

Fig. 6 is a diagram illustrating the connections of a control system utilizing switching devices built in accordance with the present invention.

It will be understood that elements forming part of one of the embodiments herein illustrated may be utilized in combination with elements forming part of the other embodiment to form further embodiments of the invention.

Referring more particularly to the drawings by characters of reference, the structure illustrated in Figs. 1 to 3 comprises a fixed metallic base in form of a vertical panel Il adapted to be secured by bolts to any suitable ysupport or framework.

Base I supports the stationary contact members of the switch by means of bracket members I2 and I3 in the form of sheet metal suitably bent at right angles and welded to the base, the two brackets being joined by a rectangular insulated bar I4 welded thereon. Another bar I6 is welded on bracket i2 and is bolted on the cylinder block Il of the switch drive, which is in turn bolted on base Il. Bar I4 supports a pair of stationary contact members I8, I9 maintained thereagainst by clamps 2|, 22 each bolted to the associated contact member. The contact members may be shaped to offer suitable Contact members, but are preferably provided with the usual tips or con- y tacts 23, 24 secured thereto by means of bolts Bar 6 similarly supports a pair of stationary contact members 25, 2'! maintained thereagainst by` means of clamps 28, 28 bolted to the associated contact members and carrying removable tips 3 I, 32. Members 8 and 2'! are provided with terminal surfaces adapted to receive conductors connecting the switch with the apparatus associated therewith. If the switch is assumed to be utilized as a reversing switch, such contact members are preferably connected by a conductor 33 constituting one of the terminals of the switch and riveted to a bus bar 34. Another conductor 36 connects contact members IS and 26 and is riveted to another bus bar 3l'.

Contacts 23 and 3l are disposed opposite each other at a suitable distance to arrange such contacts for the selective engagement therewith of cooperating contacts 38, 4! bolted on a movable contact member 43. Such contact member is mounted on a block of insulating material 44 by means of a clamp 46 joined to member 43 by suitable bolts. Contacts 24 and 32 similarly cooperate with contacts 33 and 42 mounted on another movable contact member 4'! clamped on an insulating member 48. A pivot or pin 49 extends transversely through members 44 and 48 and forms the wrist pin of a forked connecting rod 5! constituting a reciprocatory driving member on which members 43 and 4'! are pivotally mounted in insulated relation therewith. Connecting rod 5| is supported on base and is given a reciprocatory movement with respect to such base as a result of the engagement of the connecting rod head with a suitable crank means such as a spherical eccentric 52 mounted on a driving shaft 5.. of which it may be an integral part. The shaft is supported for rotary movement in suitable bearings arranged within an extension of cylinder block I?. It will be understood that eccentric 52 may be replaced by other equivalent crank means, such as a crank pin mounted on shaft 53, or by a cam if connecting rod 5| is suitably guided in its movement. As connecting rod 5| does not guide contact member 43 but only imparts thereto a reciprocatory motion, clamp 46 is provided with a prolongation pivotally mounted on a pin 54 suitably fastened in a guide member 56 slidably supported in a pair of metal bushings 5|, 5S. The bushings are forced into recesses of two support members 59, 6| bolted on base II, such supports being made of insulating material for insulating oontact member 43 from base Il. Contact member 43 is also resiliently connected with supports 59, 6| and with base by means exclusive of contact members I8 and 26, such as a pair of springs 62, 63 interposed between bushings 58, 59 and the intermediate part of guide 56. insulating member 59 also supports a terminal member 64 connected with member 43 through a flexible conductor 66 and bolted to a bus bar S1 conJ necting it with the apparatus associated with the switch. Contact member 4`| is guided similarly to member 43 and is connected, through a flexible conductor, with a terminal member 68 bolted to a bus bar 69. The guide members need not be alined accurately with respect to shaft 53 for the reason that spherical eccentric 52 permits the free movement of connecting rod 5| in planes moderately oblique to the shaft.

The driving means for shaft 53 consist of a iluid operated motor of the reciprocaton type comprising cylinder block II which is bored to define two substantially coextensive parallel cylinders "II, 'I2 symmetrically arranged with respect to shaft 53 and receiving a pair of pistons '13, '|4. The pistons are provided with suitable means for insuring a substantially uid tight contact between the pistons and the cylinders, such as the well known metallic piston rings or leather seals, and are provided with racks lG, which may form integral parts of the piston. Both racks engage with a pinion 'I8 mounted on shaft 53, the movement of the pistons and of the shaft being limited by abutment of the pistons against suitable stops such as copper gaskets 19, 8|. Such movement is thus of extent independent of the engagement of contact members 43, 4'! with members I8, I3 or 25, 2l. Fluid under pressure, such as compressed air, may be selectively introduced into cylinder 7| or into cylinder l2 by means of magnet valves 82, 83 mounted on the cylinder head 84 common to both cylinders; such valves and the means for controlling the operation thereof are well known in the art and are therefore not described in detail.

Shaft 53 is preferably provided with a. crank disc 85 carrying a crank pin 8'! driving a rocking lever 88 through a connecting rod 83. Lever 88 carries a plurality of insulated contact segments 5| arranged to selectively engage with a plurality of contact fingers 92. Contact fingers 92 are connected to suitable control circuits interlocking the switch with the associated devices and serving to open or close such circuits in response to movement of the switch, as is well known in the art.

When the switch is in the position shown to cause engagement of the contacts 23 and 24 with contacts 38 and 39 respectively, the center of spherical eccentric 52 lies in an end position represented by the point A in Fig. 1. During rotation of shaft 53, such center describes a portion of a circle about the axis B of shaft 53 to reach an end position C after passing through two dead centers D and E. Operation of the switch to cause disengagement of contacts 23, 24 from contacts 38 and 39 and to cause engagement of contacts 3|, 32 with oontacts 4| and 42 is obtained by admitting air under pressure into cylinder I2 by means of valve 83 while discharging the air present in cylinder l! to atmosphere by means of valve 82. Piston 74 is thereby urged downward and causes rotation of drive shaft 53.

During such rotation, the center of eccentric 52 moves counterclockwise when viewed as in Fig. 1, first, approaching dead center D. The resulting movement of contact member 43 is a rocking movement imparted thereto by connecting rod 5|, member 43 rotating about contact 23 against the action of spring 62. The center of eccentric 52 thereafter moves away from dead center l), and connecting rod 5| receives a downward motion, thus permitting spring 62 to impart a rocking motion to contact member 43 and thus causing contact 23 to rock on contact 38 with a combined rolling and wiping motion. Contacts 23 and 38 continue to be urged into mutual engagement by spring 62 while the center of eccentric 52 travels to a point a predetermined distance from dead center D, at which point springs 62 and 63 are in equilibrium and maintain guide 56 in the median position thereof. It will be observed that distance A-D must be less than substantially the above mentioned predetermined distance, as contacts 23 and 38 must remain engaged when the switch is in the position shown.

Continued movement of shaft 53 causes contact member 43 to rock about pin 54, which is then stationary, until the center of the eccentric reaches a point a predetermined distance from dead center E, at which time contacts 3| and 4| come into engagement. Further movement of the center of eccentric 52 toward and through dead center E causes contact member 43 to rock about contact 3|, whereby contact 4| is given a combined rocking and wiping motion about contact 3|, the two contacts being maintained in engagement by spring S3. Such movement is arrested by abutment of piston 13 against washer 19, the center of eccentric 52 then reaching point C. Besides urging contacts 3| and 4| into engagement, spring 63 also tends to move eccentric 52 away from dead center E. When the center of eccentric 52 passes through dead center E, spring 63 therefore urges the eccentric towards the end position thereof and maintains it in such end position even if the supply of compressed air to cylinder 12 should fail for any reason. Of course, care must be taken that point C be distant from dead center E by less than substantially the above dened predetermined distance to avoid disengagement of contacts 4| and 3|. During such operation, the movement of contact member 41 is identical to that of contact member 43 and need therefore not be considered in detail.

The switch may be returned to the position shown by admitting air under pressure into cylinder 1| and releasing the pressure in cylinder 12, and upon completion of such return movement, spring 62 maintains the switch in the position shown even if the supply of compressed air should fail.

The embodiment illustrated in Figs. 4 and 5 diiers from the embodiment illustrated in Figs. 1 to 3 in particular in the use of two connecting rods and of a base adapted to be bolted on a horizontal surface. A number of essential elements of the switch are, however, common to both embodiments, and are designated by the same reference numerals in all figures, even though the coniguration and arrangement thereof may be different in the two embodiments,

In the present embodiment, the switch is -supported by a base or frame consisting of two up" right members 93, each having a web provided with bosses arranged to abut against the end of a plurality of tubular struts 94. rIhe two ends of each tube each receive a threaded strut 96 fastened therein by means of a pin or otherwise, such struts being inserted in holes drilled in the upright bosses and secured therein by means or" suitable nuts. The tubes are covered with insulating material and serve as supports for the several current carrying members of the switch. The uprights are provided with further bosses for bolting thereon of cylinder block |1 of the driving motor and for receiving a pair of bearings 91 for shaft 53. Contact member 43 and clamp 46 are replaced by a pair of identical members 98 pivotally mounted side by side on the wrist pin 99 of a connecting rod |0| actuated by eccentric 52 and each carrying one Contact tip 38 and one contact tip 4|. Member 41 and the associated clamp are similarly replaced by a pair of members |02 pivotally mounted on the wrist pin |l3 of a second connecting rod |04 actuated by a second spherical eccentric |05 on the shaft Members 98 are each associated with a separate guide member 555, and each member |02 is likewise associated with a separate guide member so as to insure the proper movement of the movable members while permitting the contact tips thereoi` to be all separately urged against the associated fixed contact tips. Eccentrics 52 and |06 have the centers thereof in substantially opposite radial planes of shaft 53 to impart opposite reciprocatory movement to members 98 and |02. Such arrangement permits arranging contact members I8 and 21 side by side so that the conductor 33, which is provided when the switch is to be used as a reverser, may be reduced to a pair of links bolted on members I8 and 21 jointly with the terminals of the cables or of other conductors connecting such members with the apparatus associated with the switch. Members I9 and 26 are also arranged side by side and the contact tips of members 98 and |02 are numbered to maintain the correspondence of the circuits in the two embodiments. As the movable Contact members are metallically connected with the connecting rods, and as shaft 53 is in metallic connection with the switch base, the connecting rods must include insulating members for insulating the movable contact members from the base. Rod lill, for example, includes a section |01 of insulating material fastened on the big end of the rod by a bolt |08 and secured to the other end by means of a sleeve |09. The other connecting rod |04 is similarly constituted.

The switch thus comprises a pair of similar switch elements each associated with one of eccentrics 52, 06 driving the movable contact members 93, 1&2 of the switch elements through connecting rods 10|, |04. The arrangement of eccentrics 52 and |06 in opposite radial planes results not only in a reduction of the size of conductors 33 and 36, but also in causing the thrusts of the resilient means of the switch elements on shaft 53 to be exerted in substantially opposite directions. The stresses introduced in shaft 53 and in bearings 91 by such thrust are thereby materially reduced, so that the dimension and the weight of shaft 53 and of the bearings may accordingly be reduced to a minimum Value.

Fig. 6 illustrates in a diagrammatic manner two examples of application of a switch similar to that illustrated in Figs. 4 and 5 to the control of the driving motor of an electric vehicle. Such Vehicle is assumed to be driven by a motor of the series commutator type operable by means of either direct current or alternating current. The motor may receive alternating current from a trolley line ||2 through a transformer H5 provided with suitable tap changing equipment, or may receive direct current from a generator ||4 driven by a prime mover ||6 carried by the vehicle. The changeover from one source of supply to the other is effected by means of a switch of the character herein described, but not provided with conductors 30 and 36, which connects either source directly with the field of the motor. The armature of the motor is serially connected with the field thereof and with the source through another switch of the character herein described operable to reverse the connections of the armature to cause reversal of direction of rotation of the motor.

The switches herein described are not generally adapted to interrupt current of appreciable magnitude, and the current of motor I l I is therefore interrupted by opening of one or the other of a pair of circuit breakers H'! before the changeover switch or the reverser are operated. It will be understood, however, that the switches herein described may also be provided with suitable means known in the art for rendering such switches operable to interrupt current, such as arcing horns, blowout coils, arc chutes or other devices associated with the contact members of the switch. Each switch may also comprise any number of groups of cooperating fixed and movable contact members as may be rendered necessary by the number of circuits to be controiled or by the intensity of the current in such circuits. The shaft of the switch is then provided with a suitable number of eccentrics or of other crank means, each associated with a connecting rod carrying one or more movable contact members.

Although but two embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various modifications and changes may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

l. In a switching device, a xed base, a reciprocatory driving member supported on said base, an insulating member pivotally mounted on said driving member, a contact member rigidly mounted on said insulating member, another insulating member rigidly mounted on said base, and means resiliently connecting said Contact member with the second said insulating member.

2. In a switching device, a iixed base, a reciprocatory driving member supported on said base, an insulating member pivotally mounted on said driving member, a contact member rigidly mounted on said insulating member, another insulating member rigidly mounted on said base, a guide member slidably supported on the second said insulating member and having pivotal connection with said contact member, and spring means interposed between said guide member and the second said insulating member.

3. In a switching device, a fixed base, a reciprocatory driving member supported on said base, said member including a section of insulating material, a contact member having pivotal connection with said driving member, an insulating member rigidly mounted on said base, and means resiliently connecting said contact member with said insulating member.

4. In a switching device, a fixed base, a reciprocatory driving member supported on said base, said member including a section of insulating material, a contact member having pivotal connection with said driving member, an insulating member rigidly mounted on said base, a guide member slidably supported on said insulating member and having pivotal connection with said contact member, and spring means interposed between said guide member and said insulating member.

5. In a switching device, a iixed base, a reciprocatory driving member supported on said base, a contact member having pivotal connection with said driving member, a pair of contact members supported on said base and arranged for the selective engagement of the first said contact member therewith, and means resiliently supporting the rst said contact member on said base, to thereby effect a rocking motion of the rst said contact member into selective connection with the said pair of contact members.

6. In a switching device, a fixed base, a reciproca-tory driving member supported on said base, a contact member having pivotal connection with vsaid driving member, a pair of contact members supported on said base and arranged for the selective engagement of the first said contact member therewith, means for imparting to said driving member movements of extent to cause movement of the rst said contact member into and out of engagement with the second said contact members and independent of the engagement of the rst and second said contact members, and means resiliently supporting the first said contact member on said base, to thereby effect a rocking motion of the first said contact member into selective engagement with the said pair of contact members.

7. In a switching device, a iixed base, a shaft having crank means supported for rotary movement on said base, a driving member connected with said crank means to receive a reciprocating motion upon rotary movement of said shaft, a contact member pivotally mounted on said driving member, another contact member supported on said base and arranged to engage With the first said contact member when said crank means is within a predetermined distance of a dead center thereof, means for drivingsaid shaft to move said crank means from a distance greater than the predetermined distance through the dead center to an end position distant from said dead center by less than substantially the predetermined distance, and resilient means connecting the first said contact member with said base to urge said contact members into engagement and to urge said crank means into the end position after passage thereof through the dead center.

8. In a switching device, a xed base, a shaft having crank means supported for rotary movement on said base, a driving member connected with said crank means to receive a reciprocating motion upon rotary movement of said shaft, a contact member pivotally mounted on said driving member, a second contact member supported on said base and arranged to engage with the first said contact member when said crank means is within a predetermined distance of a dead center thereof, a third contact member supported on said base and arranged to engage with the first said contact member when said crank means is within a predetermined distance of the other dead center thereof, means for driving said shaft to move said crank means from one end position distant from the one dead center by less than substantially the predetermined distance through both the dead centers to another end position distant from the other dead center by less than substantially the predetermined distance, and resilient means connecting the first said contact member with said base to urge the iirst said contact member into engagement alternately with the second and with the third of said contact members and to urge said crank means into one of the end positions after passage thereof 75 through the dead center nearest said one of end positions.

9. In a switching device, a xed base, a shaft having a pair of crank means having the centers thereof in substantially opposite radial planes; a switch element comprising a driving member connected with one of said crank means to receive a reciprocatory motion therefrom upon rotary movement of said shaft, a contact member pivotally mounted on said driving member, another contact member supported on said base and arranged to engage with the rst said contact member, and resilient means for urging said contact members into engagement; and a second switch element similar to the first said switch element and associated with the other one of said crank means whereby the thrusts of the resilient means of the said switch elements on said shaft are exerted in substantially opposite directions,

10. In a switching device, a fixed base, a switch operating shaft supported on said base, and means for driving said shaft including a pair of coextensive parallel cylinders mounted on said base symmetrically with respect to said shaft, a piston in each of said cylinders, a rack on each of said pistons, a pinion mounted on said shaft and engaging with said racks, and means for selectively introducing iiud under pressure into said cylinders to cause rotation of said shaft in the one or in the other direction.

11. In a switching device, a fixed base, a shaft supported on said base having a pair of crank means having the centers thereof in substantially opposite radial planes; a switch element comprising a reciprocatory driving member connected with one of said crank means, a contact member pivotally mounted on said driving mem ber, a pair of contact members mounted on said base and arranged for the selective engagement of the first said contact member therewith, and resilient means connecting the rst said contact member with said base; a second switch element similar to the first said switch element and associated with the other one of said crank means, a pair of coextensive parallel cylinders mounted on said base symmetrically with respect to said shaft, a piston in each of said cylinders, a rack on each of said pistons, a pinion mounted on said shaft engaging with said racks, and means for selectively introducing fluid under pressure into said cylinders to cause rotation of said shaft in the one or in the other direction.

WALTER GIGER. CHARLES PETER.

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