US1596021A - Electrical reversing switch - Google Patents

Description

Aug. 17, 1926. 1,596,021

. C. H. RASMUSSEN ELECTRI CAL REVRSING SWITCH Filed June l2. 1923 2 Sheets-Sheet l armAsMussEn Aug. 17 1926.

ELECTRICAL mwERsmG s'wmcn i 'Filed June SheetS-heet 2 Gllhzun",

CHRASMUSSE N.

Patented Aug. 17, 1926.

UNITED STATES -Pa'rl'fzN'rg OFFICE.

CHRISTIAN Hi. RASMUSSEN, OF CLEVELAND, OHIO, ASSIGNO'R T0 THE EUCLID ELEC- TRIO 6c MANUFACTURING COMPANY, OF EUCLID, OHIO, A CORPORATION OF OHIO.

ELECTRICAL REVERSING SWITCH.

Application tiled June 12, 1923. Serial No. 644,970.

. My invention relates to an improvement in an electrical reversing switch, and my general object is to provide a reversing switch in which separate sets of pivoted contact fingers are adapted to be operated alternatively by cams and in which the contact fingers are particularly arranged and constructedr to effect a rubbing contact in turning on the electric current and to make a quick break in cutting off the current. To effect a quick break I provide a cam shaft having a loosely-connected crank handle and co-operating devices adapted to permit the cams to be rotated independently of the handle in a limited degree, and to effect a rubbing contact I pivot separate spring-pressed contact fingers upon independently pivoted spring-pressed members adapted to be operated by the cams, all as hereinafter shown and described and more particularly pointed out in the claims.

In the accompanying drawings, Fig. 1 is a vertical section and side elevation of my improved electric reversing switch on line 25 1--1 of Fig. 2, and Fig. 2 is a vertical section of the same parts, on line 22 of Fig. 1. Fig. 3 is a perspective view of the operating index member for the cam shaft. Fig. 4 is a perspective view of one of the cams. Fig. 5 is a view corresponding to Fig. 2, showing the separate sets of contact fingers in and out of contact. Fig. 6 is a front view of the switch casing partly broken away, showing lthe inner switch 'parts in the same y rposition as in Fig. 5, and-the handle moving toward the left and the cam in a position about to permit a quick break of the contact finger. Figs. 7. 8 and 9 areperspective views of one of the stationary contact o members, one of the supporting yokes, andy oneof the cam operated members ,carried by said yokes. respectively.

The invention comprises a casing 2 having a base plate 3, side plates 4-4, and a 5 'removable cover or enclosing plate 5. Side plates 4 are formed with integral lugs 6 and 6 extending inwardly at different elevations which are `adapted vto support fiat crossconnecting lstrips 7 and 8, respectively, made Lof fiber or other ysuitable electrical insulatsleeved over the squared middle part 11 of the shaft to support a pair of cams 14 and 15 in fixed insulated position thereon. Round kfibre sleeves 16 separate the cams from each` other and the opposite side walls 4, and the longer round end 10 of shaft 9 is preferably journaled in a stationary bushing 17 fixed within and extending outside of plate 4 where a crank handle 18 may be supported to turn freely within limits thereon. A pin 19 near the hub'portion of the handle extends between two striking project-ions 2() 2() upon the periphery of an index member 22 keyed or pinned to cam shaft 9, and a series of radial grooves 23 are formed in the outer face of index member 22 to receive the key or locking pin gages one of the projections 20 before ro- F tating the cam shaft, andconversely this free play between the index projections'and pin 2() permits the cam shaft to rotate and the cams to be kicked out of action quickly by springs'when the crank handle is being turned rby hand in switching off the electric current.

Thus, each cam comprises a segmental portion 24 of less than one-hundred and eighty degrees in circumference which provides a high circular cam surface 25 terminating in abrupt straight inclines 26," and the round hub portion 27 of the cam provides a low cam surface 28 concentric with the high cam surface between the steep cam inclines 26. The two cams are spaced rapart on the shaft'with their respect-ive segmental portions 24 extending in opposite directions from theaxis, and the arcuate shape of each segmental portion 24 is such that co-incidental engagement of a pair of rollers 29 is permitted with the low cam surface 28 at the base of the inclines 26 in the neutral or normally switching ofi positionof the cam shaft. However when the camshaft is rotated in either direction, and referring to both cams,

'one roller opposite each cam rides upon the high surface and ismoved outward, and anotherroller opposite each cam rides upon the low surface without shift or change in`po`sition. As ai' result, the oscillatory or pivoted supports 30 for the respective rollers are rocked to move the pivot Contact fingers 31 carried by said members, thereby switching n lthe electric current on' and off. As shown four sets of such oscillatory members and pivoted lingers are operated by the two cams to effect reversal and control of the directional flow of the electric current, and as each. set of oscillatory members and fingers are identical adescription of one will sullice for all four. Thus, each oscillatory member 30 is made of metal in the irregular form substantially as delienated in Fig. 9, and comprises a forked extremity 39. extending laterally from the main stem or body 33 of said member to receive a roller 29, a pair of spaced arms 34 extending laterally from about the middle of the stein or body 33 adapted to provide a double pivot connection, and a vertical outwardly offset extension 35 adapted to provide a seat andconnection for a compression spring 36 for a contact finger 3l. This finger is pivotally connected at its lower end to a cross pin 37 fixed or liouriialed within arms 33, and a screw 38 is screwed into the finger and has free movement at its outer headedend within a large opening or slot 39 in extension 35. The spring is sleeved upon the screw stem andcngaged with the finger to hold ityieldingly in a fixed position opposite one of' the curved contact lugs 40 of an electricscurreiit conducting bracket 4l which is screwed or bolted to one side edge of the upper fiber strip S. Finger 3l is alsorprovided with a removable and replaceable contact tip 42 of any suitable shape or form, and a fiexible conductor 43 connects the finger with a yoke member 44 seated and fixed upon the lower fiber strip 7. Yoke 44 comprises depending legs 45 which are straddled by the respective arms 33 of oppositely situatedl oscillatory members 30, and the legs are bent outwardly and downwardly to fit within the space formed between arms 33 and' forked extremity 3:2. Arms 33 are hinged or pivotally connected at their outer ends to legs 45, and* a bolt 4G is loosely connected atone end to the extremity of each leg 45 and extends through a large opening or slot in the body 33 of the oscillatory member and beyond the outer face thereof' to permita compression spring 4T to be mounted upon the bolt. Spring 47 bears against a washer 4S fixed upon the outer end of bolt 46 and the function of this spring is to maintain a constant working engagementof roller 29 with cam 14. lVhen the cam revolves andv forces the roller outward the oscillatory member compresses spring 47, and the oscillatory movement imparted by the cam/ to the said member is transmitted to the contact finger carried by such member. The contact end or tip 42 of the finger moves in an arc until it strikes the stationary contact lug 40, whereupon a. vert-ical rubbing movement is caused by the upward movement of the finger due to a continued movement of its pivot connection 37 on an arc described from the hinge or pivot pin 49 of rock member 30. The coiled spring 3S behind the finger compressed during the rubbing movement which assures good electrical contact at lug 40, and this lug is curved or swells outwardly to further facilitate the making of' a good rubbing Contact.

Two electric-curront coiulucting brackets 4l are mounted upon fiber strip S, each haviaced coiitact lugs 40 and a .single peri terminal projection 50. Separate electrical wires or conductors 5l and 52 connect with the terminal projections 50 dependine' :in the separate brackets 4l, and a pair electrical wires or conductors 53 and F4 connect with the terminal lugs 'l-5l in'ojecting upwardly from thc separate ji'okes 44, and these electrical connections are made in the present instance with a view of effecting a ie.ersal of electric current at the election of the operator in switching operations. Thus it will be noted in Fig. Q that all the contact fingers are thrown back or out of Contact when the rollers on all four oscillatory members occupy low points ou the cams. it being of course uuderstood that two of' the contact fingers are hidden in Big. Q because they lie in a plane immediately behind the two fingers shown in the 'forcgrouml However, both cams are visible because reVersely-related on the cam shaft. ow if the cani shaft rotated in either direction by means of' crank handle 1S only one pair of Contact fingers 3l will be thrown into contact with a pair oil. contact lugs 40. and the fingers which are thus operated will be ou opposite sides of the cam shaft and diagonally related to each other. This is exemplified in Fig. where the cam shaft has been rotated from a neutral or off position to bring one contact finger 3l in the Yforeground at the left in contact with its conipleinentary contact lug 40, and a second contact fingerl Slb in the background at the right in contact with its complementariy Contact lug 40T. The other pair o't'contact fingers 3l@ and 31d are held in a retired position because the rollers of their respective oscillatory members are riding upon or engaged with the low portions of the two cams. Now assuming that the electric current is to be switched off, the parts in the position shown in Fig. 5 will effect a quick break, which permits this reversing switch to be used with electrical apparatus requiring an electric current of high voltage or ampe age or where excessive sparking is apt to occur in breaking or switching off the current. Thus, referring to Figs. 5 and G. when crank handle 18 is turned to rotate the cam shaft pin 19 effects such rotation by engaging the index pro- ]ection Q0 in the path of movement of the pin. Assuming this movement is in the direction of arrow -i-"rand the end of the high point on the cam has just been reached to ermit roller 29 to ride down the vsteep inc ine, the retirement of finger 31 and break of contact is instantaneous because the instant the roller rides off the high point and engages the straight incline the compression spring 47 will force the oscillatory member toward the cam and revolve the cam at an accelerated speed in the same direction as previously turned by the crank handle and obviously without check or hindrance by the operator while the operator holds the handle. This quick break is effected as the handle and cam shaft approach the neutral position from either direction in switching off the current, the working arrangement of the cams and switch fingers being designed for that purpose, all as herein shown and described.

What I regard as my invention or discovery, and desire to claim, is

1. An electrical switch, comprising a rotatable shafthaving a pair of reversely positioned cams thereon, a cross piece having a pair of yokes situated thereon opposite said shaft each having a pair of oscillatory members hinged thereto at the lower end of the legs of the yokes and adapted to be operatively engaged by said cams, a contact finger pivotally connected to each oscillatory member opposite its hinge pivot, and a separate cross piece having contact members adapted to be engaged by said fingers.

2. yAn electrical switch, comprising a casing having side plates and connecting strips of insulating material for said plates at different elevations therein, a shaft journaled in said plates having a crank handle, cams mounted upon said shaft, yokes straddling one of said strips, oscillatory members hinged to the lower ends of said yokes having roller engagement with said cams, contact ngers pivotally connected to said oscillatory members laterally of their hinges, and conducting contacts mounted in the same vertical plane as said hinges upon one of the connecting strips opposite said fingers.

3. An electrical switch, comprising a casing having side plates, a shaft journaled within said plates having an index member and provided with a crank handle having a limited free play relative to said index member, a pair of cams upon said shaft, cross pieces within said casing parallel with said shaft, yokes mounted opposite the shaft upon a cross piece having spring-pressed oscillatory members hinged the-reto and provided at one end with rollers engaged with said cams, a contact finger pivotally supported and spring-pressed upon each of said oscillatory members, and separate contacts upon a cross piece stationed intermediate the contact ends of pairs of said fingers and adaptedfto be engaged thereby when the cam shaft is rotated.

4. An electrical switch, comprising a squared shaft having a sleeve of insulating material thereon, cams fixed to said sleeve, separate spacing sleeves of insulating material upon said first sleeve between said cams, yoke conductors mounted adjacent said cams having legs and oscillatory members suspended from each leg upon opposite sides of said shaft and cams, freely movable contact fingers carried by said oscillatory members, and Contact conductors sta tioned opposite said fingers and adapted to be engaged thereby.

In testimony whereof I affix my signature hereto.

CHRISTIAN H. RAsMUssEN.

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