US1957737A - Switch - Google Patents

Description

May 8, 1934. A. G. STEINMAYER SWITCH Filed March l, 1929 2 Sheets-Sheet l FZ5: gf

May 8, 1934.

A. G. STEINMAYER SWITCH Filed March lI 1929 FZ5. E

2 Sheets-Sheet 2 SWW/mito@ Patented May 8, 1934 UNIT STATES Application March l, 19%, Serial No. 343,?9

9 Claims.

This invention relates to electric switches, and is particularly directed to oil switches, either of the single or multiple type.

In switches for handling relatively large currents it has been the practice to provide stationary contact blocks and a formed or curved movable brush or contact member which was made of a plurality of laminations, and which was moved into contact with the stationary contact blocks. Each of the laminations had to be separately formed, as no two of them were alike, and as they were of successively less curvature and of different lengths.

The flexible curved brush, or movable contact member, was depended upon to secure a good electrical contact with the stationary contact members or blocks, and the operating means rigidly carried this brush and was itself rigidly restrained or held in its path of travel. Considerable elTort was therefore required in closing the switch, as the curved brush had to be ilexed -or bent through a relatively great range or, in other words, to a considerable degree, in order to secure good contact.

These switches had other defects, among which may be mentioned the difficulty of renewal of the contact blocks and other parts when they became pitted or worn, and the dii'iiculty of securing and maintaining the proper adjustment of the contacting members of the switch.

This invention is designed to overcome the defects noted above, and objects of this invention are to provide an electric switch in which the stationary contacts are each composed of a laminated structure, no lamination of which has to be formed, in which a simple type of movable contact member is provided such, for instance, as a straight copper bar, and in which the switch is so constructed that the parts are free to automatically adjust themselves relatively to each other, so that a good electrical contact is insured at each operation of the switch.

Further objects are to provide a switch in which the movable Contact members or bars are carried by freely swinging or movable means, and in which the contact members are themselves loosely held and may individually freely rock or adjust themselves to insure perfect contact with the stationary contacts or laminated members.

Further objects are to provide simple means for removably holding the movable contact member or bar loosely in place, and for removably holding a replaceable auxiliary or iinal contact member, such means permitting the contact bar (Cl. EGO-150) to be turned over, ii desired, when pitted or worn to thereby present a new face and also permitting the replacement of the contact bar when required.

Further objects are to provide a switch in which no yoke other complicated structure is employed for holding the laminations together, but in which the laminations are tightly' clamped to the terminal blocks by simple means, and in which 'the laminations are merely straight, unormed strips.

Further objects are to provide a simple form of auxiliary or linal contact member, which freely adjusts itself so that it is always the last to break contact irrespective of any wear of the parts, and which preferably contacts with readily renewable clamping plates which bind o1' hold the laminations in place, such plates also cooperating with the auxiliary contact member t0 guide the parts into position during the closing movement of the switch.

Further objects are to provide a switch of simple construction, which may be readily manufactured and assembled, and in which the parts may be most easily renewed.

Embodiments of the invention are shown in the accompanying drawings, in which:-

Figure l is a transverse sectional view through the switch.

Figure 2 is a longitudinal sectional view on the line 2-2 of Figure 1.

Figure 8 is a sectional view on the line 3-3 of Figure 2.

Figure i is a view taken on the plane indicated by the line 4-4 in Figure 3, such View being drawn to an enlarged scale.

Figure 5 is an enlarged sectional View on the line 5-5 of Figure 3.

Figure 6 is a detail of the contact carrying member.

Figure 7 is a view corresponding to a side elevation of the structure shown in Figure 4, showing a slightly modied form.

Referring to the drawings, it will be seen that the switch comprises a body portion l provided with a removable cover 2 and a removable oil compartment or lower housing 3 which houses the contacts of the switch. This lower housing may be provided with insulating lining in the usual manner. The cover may be held in place by means of bolts 4, and the oil compartment or lower housing 3 may be held by swinging bolts 5 pivotally carried by the body portion l and received by slotted ears 6 attached to the oil compartment or lower housing 3. Preferably, gaskets are interposed between the body portion and the cover, and between the body portion and the lower housing. The body portion inay be provided with ears 7 for attachment to any suitable support.

A partition 8 is bolted to the body portion 1 and divides the body portion from the oil com partinent or lower housing 3. The partition 8 carries the twoepart insulating sleeves 9 through which the conducting rods or bolts 10 pass. The upper ends oi the bolts 16 are threaded. and are provided with nuts 11 which receive the wires or cables. Insulating bushings 12 are provided, through which the cables may pass, such bushing extending downwardly through the lower wall of the body portion where such lower wall pro jects beyond the oil compartment or lower housing as shown in Figure 1. The bushings for the incoming cables are located on one side of the switch, and the bushings for the outgoing cables are located on the opposite side of the switch.

The lower ends of the bolts or rods 16 are threaded into, or otherwise rigidly attached to. lower terminal blocks 13. When the lower or^ the nuts 11 are tightened, the two-part sleeves 9 are clamped tightly to the partition 3 and the termi-- nal blocks 13 are securely locked in place against the lower ends of the insulating sleeves 9.

It is preferable to divide the oil compartment intoseveral chambers in which the separate elements of the switch are located. The division walls of these individual compartments may be lined with insulating material in accordance with the usual practice.

The switch is operated by means of a rock shaft 14 journalled in bearings l5 carried by the partition 8 and provided with an externally located operating handle 16. The shaft 14 is provided with spaced. levers or rock. arms 17, each of which is joined by means of a pair ci?` links 18 to a crosshead 19, the links 18 and the levers 17 constituting toggle joint mechanism. The levers 17 are provided with extensions or locking lips 20, which engage stops or pins 21 carried by the links 18 when the levers have been rocked slightly past dead center, corresponding to switch closed position, as shown in full lines in Figure 1. Thus, a powerful force is obtained in the nal closing motion ci" the switch. Further, it will be noted that no stop required for the operating handle, as the locking lips 2O and the stops or pins 21 arrest the motion or" the operating handle 16 at the closed position of the switch, and retain the mechanism in this position as the levers 17 have just passed dead center. Force is required to again. rock the levers 17 backwardly past. dead center, and after they have passed dead center, this resista-nce is suddenly relieved and the switch, therefore, snaps open with a quick break, thereby 1ially reducing arcing. The switch, when open, tends to remain in open position, as the weight of the moving parts holds the levers 17 in their lower position, as shown in dotted lines in Figure 1.

The crosshead 19 may consist of a straight steel bar loosely guided by pins 22 carried by extending upwardly lfrom the partition 8.

Insulating contact carrying rods 23 extend downwardly from and are carried by the crosshead 19, as shown in Figures 1 and 2. These rods may be made of a tough wood or other insulating material, as they dip into the oil and become oil Asoaked if of wood and give practically perfect insulation. The upper ends oi the rods are surrounded by and pinned to threaded adjusting sleeves 2e. Thesey sleeves are screwed into the crosshead 19, and are locked in adjusted position by the lock nuts 25. The sleeves 24 afford adjustment for the movable contacts carried adjacent the lower ends of the rods, as will be described hereinafter.

Contact carrying cradles or members 26 are carried by and receive the lower ends of the rods 23, and are pinned or otherwise secured to the rods. cradles arc, in reality, forked members, and are provided with spaced ears between which the movable contact ineinbers 28 loosely extend, uch members being loosely retained in place by neans of pin 29 passing below the contact meiner and provided with a head at one end and a removable split pin 3G at the other end, shown ii- Figures 2 and 6.

Each the movable Contact members 23 con- .iss of a flat copper bar which may be cut froin stock material and requires no shaping or forniM ing whatsoever. Each of the contact bars is provided with an auxiliary or nal contact member 31 which may consist of a strip oi phosphor bronze spring held in place by means of a pair of spaced screws 32. The auxiliary contact strips S1 are provided with upturned ends 33, and the ends may terminate in inwardly rolled extremities as shown most clearly in F 3.

it is to be noted from Figure 3 that the screws 32 extend upwardly beyond the contact bar 28, and are space slightly from opposite sides of the cradle or Contact carrying members 26. rEhese screws thus, not only hold the auxiliary contact strip 31 in place, but also position or retain the contact bar 28 and loosely hold the contact bar against longitudinal sliding motion. The contact may thus rock slightly and accurately adjust itself to the stationary contacts when the switch closed.

Further, the construction provides for the ready renewal or the auxiliary contact stripsand contact bars. Any contact bar and its auxiliary contact strip may be readily removed by with-- drawing the corresponding. pin 29. The auxiliary contact strip may be removed by removing the screws 32 and a new strip substituted, or if required, a new contact bar may be substituted for a worn or pitted cont-act bar.

The stationary contacts each consist of a block of laminations 34 held tightly clamped between the terminal bl cke and a clamping plate 35. A plurality of spaced screws 36 extend throngT1 the plates and the laminations or brushes and are screwed into the terminal blocks. A shoulder or notch is ici-ined in each contact block 13, shown in Figures 1, and 7, and provides a face against which the laminations bear and an abutting shoulder for the rea. s of laminaticns, thereby providing ineensJ Loir aiding in holding the lamine-.tions securely in against shifting. Preferably lower edge oi eachv of the plates 35. beveled as indicated at 37 in Figures 3 and 7, to facilitate tl sliding of the ends 33 ci the auxiliary contact strips 31 upwardly over these clamping plates, during closing motion of the switch.

As previously stated, the crosshead 19 loosely guided the pins 22, and, consequently, the lower ends i the rods 23 may rock to a limited extent. The auxiliary contact strips 31 cooperate with the plates 35 of the stationary contacts and aid in centering or properly positioning the movable contacts or bars 28' during closing movement oi' the switch.

The movable contacts or contact bars 23 may freely adjust themselves to stationary contacts, and thus secure perfect contact. Therelos;

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fore, in addition to the general adjustment or common adjustment aiforded by the loosely guided crosshead with the depending rods 23, each contact bar28 may individually adjust itself -to its stationary contacts.

It is to be noted during the opening movement of the switch, that the auxiliary contact strips leave the plates 35 after the contact bars 28 have left the stationary laminated contacts 34. Thus, the final break occurs only between the ends of the auxiliary contacts and the plates 35, and, due to the quick break as previously described, arcing is reduced to a minimum.

The laminated stationary contacts are slightly flexed or compressed by the contact bars 28 when the switch is closed, and thus a decided pressure or force is produced which tends to hold the toggle joint of the operating mechanism in its position slightly past dead center, as has been previously described. Thus the switch is yieldingly held locked in closed position and good contact is maintained until the switch is again positively opened.

The laminations are formed of springy copper strips or other suitable material, and preferably one or more of the uppermost and lowermost of the laminations are made heavier than the rest.

In the modified form shown in Figure 7 the upper and lower laminations are heavier, and the heavier upper laminations are of successively increasing length. This construction materially strengthens the block of laminations and prevents sharp localized bending, but, instead, secures a gradual bending of the block of laminations. The heavier upper laminations are indicated by the reference character 38, and the heavier lower lamination, by the reference character 39.

The operating mechanism is described and claimed in my Patent No. 1,770,953 of July 22, 1930, for Switch and operating mechanism therefor, led March 1, 1929.

It is to be particularly noted that no lamination need be formed or shaped, but that straight laminations are employed. These straight laminations are clamped tightly in place and are ground to the required angle.

Instead of a group of curved, separately formed laminations for the movable contact, as has been the practice heretofore, a simple straight bar of copper is employed. This greatly reduces the cost of manufacture and simplifies the assembling.

The switch obviously may be made either single, or multiple as shown in the drawings without departing from the spirit of this invention.

The freely swinging contact carrying rods 23, which are allowed to swing through a limited range, provide for a rough adjustment of the movable contacts or bars with reference to the laminated stationary contacts. In addition to this, the construction is such that each contact bar may separately adjust itself to its stationary xcontacts, thus securing a perfect electrical contact.

Further, it will be noted that each time the switch is closed, the stationary contacts slide slightly with reference to the movable contact bars and thus provide a slight scraping action which keeps the contacts clean.

A further point to be noted is that the threaded sleeves 24 provide an individual adjustment for each contact bar, so that the pressure exerted by each bar may be predetermined by the initial adjustment of the switch.

If any one of the insulating rods 23 should happen to break, the corresponding contact bar 28 would merely fall away from the active portions of the switch, and no damage would be done to other portions of the switch, and no destructive arcing would occur even at the broken element of the switch. An added safety feature is secured by this construction, for when the switch is open, all lines are open even if one or more elements of the switch have become broken.

It will be seen that a novel form of switch has been provided by this invention, which, although possessing the desirable characteristics discussed, is nevertheless of simple construction, and is free from fragile or delicate parts.

Further, it will be seen that the switch is so made that it may be cheaply produced, as it eliminates expensive and slow operations in forming and assembling.

It is clear that the parts of the switch could be reversed, that is to say, the blocks of laminations could be movable and the stationary contacts could have the plane faces, and other departures from the precise disclosure could be made Without departing from the spirit of this invention. Therefore, although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

l. An electric switch comprising a pair of stationary contacts, a movable contact, means for pivotally supporting said movable contact and for moving said movable contact into and out of engagement with said stationary contacts, an auxiliary contact strip carried by said movable contact, and fastening means removably locking said auxiliary contact strip to said movable contact, said fastening means restraining said movable contact from sliding from said rst mentioned means.

2. An electric switch comprising a pair of spaced stationary contacts, a contact bar adapt'- ed to bridge said stationary contacts, a cradle loosely carrying said contact bar, means for moving said cradle, an auxiliary contact strip, and screws for holding said strip to said bar, said screws cooperating with said cradle to rostrain said loosely carried bar from sliding from said cradle.

3. In an electric switch, movable means, contact bars pivotally supported from said movable means, stationary contacts located above said contact bars, said stationary contacts each being formed of laminations held in place by an outer clamping plate provided with a beveled lower end, and an auxiliary contact strip carried by each contact bar and adapted to engage said clamping plates and ride over the beveled lower ends of said plates, said auxiliary contact strips leaving said plates after said Contact bars have left said laminations.

4. In an electric switch, a pair of stationary contacts, movable means, a rod depending from said movable means, a movable contact carried by said rod for cooperation with said stationary contacts, and an auxiliary contact for laterally initially positioning said movable contact with respect to said stationary contacts during the closing motion of said switch, said auxiliary contact engaging the opposite sides of said stationary contacts, said movable contact being pivotally connected to said rod, whereby said movable contact may adjust itself to said stationary contacts during the final closing motion of such switch.

5. In an electric switch, a pair of stationary contacts, a movable Contact engageable simultaneously with said stationary contacts, movable Contact supporting means for moving said movable contact into and out of engagement with said stationary contact, said supporting means pivotally and slidably carrying said mov-- able contact intermediate its ends, whereby said movable contact automatically adjusts itself both pivotally and by lateral sliding relative to said contact supporting means during 'the closing motion of said switch.

6. In an electric switch, a pair of stationary contacts, depending supporting means having a forked end, a pin carried by said forked end, and a movable Contact resting upon said pin and positioned within the said forked end, said Inovable contact being pivotally supported by said pin and being shiftable laterally with respect to said forked end.

r7. In` an electric switch, a pair of stationary contacts, depending supporting means having a forked end, a pin carried by said forked end, a movable contact resting upon said pin and positioned within the said forked end, said movable Contact being pivotally supported by said pin and being shiftable laterally with respect to said forked end, and means for limiting the sliding motion of said movable contact.

8. In an electric switch, a pair of stationary contacts, a rod extending between said contacts, means for moving said rod, a forked cradle carried by the lower end of said rod and having spaced side walls, a movable contact loosely positioned between said spaced side walls and guided by said walls, and a pin extending from one wall to the other wall and located below said movable contact and pivotally and slidably supporting said movable Contact.

9. 1n an electric switch, a pair of stationary contacts, a rod extending between said contacts, means for moving said rod, a forked cradle carried by the lower end of said rod and having spaced side walls, a movable contact loosely positioned between said spaced side Walls and guid ed by said walls, a pin extending from one wall to the other wall and located below said movable contact and pivotally and slidably supporting said movable Contact, and means for limiting the lateral sliding motion of said movable Contact.

ALWIN G. STEINMAYER.

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