US2234683A - Switch for generators - Google Patents

Description

March 11, 1941- E. H. oTTERBAcl-{ER 2,234,683

SWITCH FOR GENERA'IORSl INVENTOR.

ATTORNEYS.

March 1l, 1941. I H, OTTERBACHER 2,234,683

SWITCH FOR GENERATORS Filed Jan. ll, 1959 2 Sheets-Sheet 2 Il" Il INVENTOR.

EZZDT H. erbacher BY.." 'E {Eg ATTORNEYS.

Patented Mar. '11, 1941 UNITED STATES PATENT OFFICE 2,234,683 SWITCH Fon, GENERA'roRs Application January 11, 1939, Serial No. 250,330

2 Claims.

The present invention relates to alternating current generators of the hand operated magneto type, such, for example, as generators of the character utilized in ringing or signalingover telephone lines, and, more particularly, to improvements in rotor drive and switch operating mechanisms of the type embodied in generators of this character.

It is an object of the present invention to provide, in a generator of the character described, an improved rotor drive and switch operating mechanism Which is of extremely simple, rugged, compact and economical construction.

It is a further object of the invention to provide, in a generator of the character described,

an improved rotor drive and switch operating mechanism which possesses the above structural characteristics and which operates without lost motion or frictional drag to provide a positive driving connection between the drive shaft and the rotor of the generator and to actuate an associated circuit controlling device.

In general, the objects as set forth above are realized in accordance with the present invention by providing a magneto generator which includes a rotor, a drive shaft mounted for rotary and axial movement and a driving connection between the shaft and the rotor, together with a circuit controlling element operative in response to axial movement of the shaft. The driving connection includes a pair of cooperating elements, one of which is provided with a slot having a side terminating in a tapered camming surface. The other element includes a projection extending within the slot and having a side extending parallel With but normally displaced from the side of the slot and terminating in a tapered camming surface normally engaging the camming surface provided by` the slot. More particularly, the element in which the slot is formed comprises a rotatable sleeve in which the drive shaft is journaled and carrying a gear ernbodied in the driving connection through which power is transmitted from the drive shaft to the rotor element. The element 4from which Athe above-mentioned projection extends is mounted upon the drive shaft. By virtue of this arrangement, the camming surfaces cooperate to impart axial movement to the shaft in response to rotation of the shaft, and the parallel sides of the projection and the slot engage positively to arrest the axial movement of the shaft after a predetermined rotary movement thereof. n

The novel features believed to be characteristlc of the invention are set forth with particularity in the appended claims. The invention both as to its organization and m-ethod of operation, together with further objects and advantages thereof, will best be understood by reference to the specication taken in connection with the accompanying drawings in, which Figure 1 is an elevated perspective View of a generator having embodied therein the features of the invention as briefly outlined above; Fig. 2 is a front View in elevation of the generator shown in Fig. 1; Fig. 3 is an exploded View illustrating the elements of the iield structure ernbodied in the generator shown in Fig. 1; Fig. 4 is a diagrammatic view in elevation illustrating certain of the elements embodied in the generator shown in Fig. 1; and Fig. 5 is an exploded view illustrating certain elements of the driving mechanism embodied in the generator shown in Fig. 1.

Referring now to the drawings, the generator there illustrated comprises a supporting structure I0 which includes a back or mounting panel II, a base panel I2, and a pair of spaced-apart parallel extending side panels I3 and I4. This supporting structure is constructed of non-magnetic material, such, for example, as brass or insulating material, and preferably is formed by casting. The back panel II of `the supporting structure I Il is provided with countersunk drill holes I5 which are adapted to accommodate mounting screws or bolts, not shown. The side panels I3 and I4 are respectively provided with openings |33 and I4a having positioned therein the windings I6 and I'I of a iield structure I8 which is secured to the base I2 of the supporting structure by means of screws 9. For the plurpose of varying the reluctance of the magnetic circuit provided by the field structure I8 there are provided two `rotor elements I9 and 2l) which are mounted upon the heads 2 la and 2 Ib, respectively, of a mandrel 2| carried by a shaft 22.I The rotor element I9 is secured to the mandrel head 2Ia by means of four rivets 23 disposed around the mandrel head 2Ia and extending through this head and the rotor element I 9. The other rotor element 20 is similarly mounted upon the mandrel head 2lb. The shaft 22, upon Which the mandrel 2I is rigidly mounted by means of a set screw 24, is journaled in bearing members respectively mounted in the side panels I3 and I4. 'Ihis shaft carries at its right extremity a small gear 25 through which power is adapted to be transmitted to the shaft 22.

More particularly, the driving mechanism for the rotor elements I9 and 20 includes a shaft 26 rotatably supported within a bearing member 21 which is mounted in any suitable manner in an opening provided in the side panel I4. The shaft 26 has rigidly secured to its right extremity a collar 28 upon which is mounted a crank lever 29, Rotary movement of the shaft 28 occasioned by operation of the crank 29 is transmitted to the shaft 22 through a driving connection including a pair of clutch elements 35 and 3l and a gear train comprising the gear 25 and three additional gears 32, 33 and 34. More particularly, the clutch element 3l is in the form of a sleeve journaled in the bearing member 2l and having its internal surface arranged to journal the shaft 26. The sleeve 3l has rigidly mounted on the right end thereof the gear 34 which meshes with the gear 33. The two gears 33 and 32 are rigidly secured together and are journaled upon a stub shaft 35 extending from and mounted upon the side panel I4. The two gears 32 and 33 are restrained against longitudinal movement by means of a collar 35 secured to the shaft 35 by a set screw 3l. Similarly, the sleeve 3l is restrained against axial movement to the right by means of a collar 38 secured to the sleeve 3l by a set screw 39 and having a smooth surface frictionally engaging the adjacent surface of the bearing member 21.

The shaft 26, upon which the crank 2S is mounted, is axially movable within the sleeve 3l to actuate between two operating positions the movable spring 45 of a spring pile 4l including two additional springs 42 and 43. The actuating element for the movable spring 4i) comprises a disk 44 formed of fibre or other insulating material and carried by a collar 45 which is secured to the shaft 25 by means of a set screw 46. As best shown in Fig. 5 of the drawings, in order to move the shaft 26 axially to the left from the position shown in Fig, 1 of the drawings, against the spring bias normally exerted thereon by the movable contact spring 40, the sleeve 3| is provided with two oppositely disposed slots, one of which is indicated at 4l, each terminating in a V-shaped notch the tapered sides o-f which provide camming surfaces. These slots each include extended parallel straight sides formed by milling the sleeve 3l, the V-shaped notches being thereafter formed by cutting beyond the bases of the milled sides of the sleeve. Thus, the slot 4'! defines two straight side walls 47a and 41h in the sleeve 3l. The clutching element or collar 3i) is rigidly secured to the shaft 25 by means of a set screw 30a and is provided with a pair of oppositely disposed projections arranged respectively to extend within the slots formed in opposite sides of the sleeve 3l in the manner described above. Thus, the collar 3i) has formed integral therewith a projection i3 having straight parallel side walls adapted respectively to engage the straight side walls 41a and 41s of the slot 41, but normally displaced therefrom, and a V- shaped end, the tapered sides of which. normally snugly engage the V-shaped end of the slot 4l. lThus, the tapered sides of the projection 48 constitute camming surfaces normally engaging the camming surfaces of the slotted portion 4'! of the sleeve 3l, rThe other projection extending from the collar 3D is constructed and-arranged in a similar manner to extend within the other slot formed in the end of the sleeve 3l and oppositely disposed with respect to the slot 4l.

The springs of the spring pile 4| are mounted upon the side panel I3 through the provision of a mounting assembly which comprises four insulating members. 43, a pair of mounting screws 50 and a face plate 5l. More particularly, the screws 50 extend through registering openings drilled through the face plate 5l, the insulating members 49 and the contact springs of the spring pile 4l, and are threaded into tapped drill holes formed in the side panel I3. In this manner the Contact springs 40, 42 and 43 are insulated from each other and from the supporting structure lll.

The field structure I8 is of the improved construction and arrangement disclosed and claimed in copending application Serial No. 255,329, Albert E. Woodruff, iiled January 11, 1939. As best shown in Fig. 3, this field structure comprises a substantially U-shaped eld member 52, having two legs 52s and 521 upon which the windings IS and l'l' are respectively mounted, and a base portion 52e. The base portion 52e is recessed to receive a permanent magnet 53 and is provided with drill holes 54 for receiving the mounting screws 9, and with additional holes 55a and 55h for receiving the field structure assembly screws 55s and 55h. The upper ends of the legs 52a and 521 are notched at 51a and 51h, respectively, sc that each leg is provided with two separated pole faces. The pole face portions of the legs 52ev and 52h are arranged to be oppositely disposed with respect to the pole face portions 58a and 58s of a plate or eld member 59 which in cooperation with the assembly screws 55a and 55h serves rigidly to mount the permanent magnet 53 upon the base portion 52C of the iield member 52. More particularly, the permanent magnet bar 53 is provided with oppositely disposed slots 53gand 53h within which the assembly screws 55a and 55s are respectively disposed when the field structure is assembled, and the field member 59 is provided with tapped drill holes Gila and 68h into which the assembly screws or bolts 55a and 56h, respectively, are threaded. Although the magnet bar 53 may be formed of any desired magnetic material, it is preferably formed of an alloy consisting of 5 to 40 percent nickel, 'I to 20 percent aluminum, 0.5 to 30 percent cobalt and the remainder iron, such, for example, as the alloy commercially known as Alnico As indicated above, the rotor elements I9 and 20 are arranged to vary the reluctance of the magnetic circuit formed by the eld structure I8 thereby to cause induced voltages to be developed in the windings I6 and Il. More particularly, each rotor element is provided around its periphery with alternate magnetic and nonmagnetic sections which are adapted to be moved between the oppositely disposed pole faces of the field structure. Thus, the rotor element I9 is provided with a plurality of teeth o1' magnetic secions ISE which are alternated with a plurality of cut-out or nonmagnetic portions lh. The teeth lila of the rotor element i3 are, when the generator is assembled, adapted to be moved between the pole face portions 58a of the field member 59 and the oppositely disposed pole faces of the leg 52B- of the field member 52. In a similar manner the rotor element 20 is provided with teeth or magnetic sections 25a which are alternated with cut-out portions or nonmagnetic sections 2Ub. The teeth of the rotor element 2B are adapted to be moved between the pole face portions 58b of the field member 59 and the oppositely disposed pole faces of the leg 52h of the field member 52. The arrangement is such that the teeth or magnetic portions of one of the rotor elements register with the cut-out or nonmagnetic sections ofthe other roto-r element, it being observed that each rotor.V element is provided with the same number of teeth, and further, that the number of teeth of the elements partially determines the frequency output of the generator.

vMore particularly, and as best shown in Fig. 4, the

Ythe teeth 20a of the rotor element 29. It will be observed that the rotor elements are mounted upon the mandrel heads in such a manner that, with the shaft 22 occupying a position such that .two of the teeth 20a of the rotor element 20 are lpositioned exactly between'the two pole faces 58h land the cppositely disposed pole faces of the Ileer 52h, one of the teeth I'9a of the rotor element I9 registers with the slot 51a .of the leg 52a and none of the teeth of this element are positioned opposite the pol-e faces 59a Aand the oppositely disposed pole faces of the leg 52a. By virtue of this arrangement and :during rotation of the rotor elements the predominant portion of the flux developed by the permanent magnet bar 53 is alternately directed through .the leg-s 52h and 52e of the eld member 52. Thus, the flux linking the windings I'B and I'I is varied in respons-e to rotation of the rotor el-ements I9 and 20 so that undulating volt-ages are developed in the coils I6 and I1.

In assembling the elements of the generator as described above, the field structure, as shown in Fig. 3, is first assembled in the manner just explained, with the windings thereof positioned upon the legs 52aand 52s, following which the assembled field structure is positioned between the side panels I3 and I4 of the supporting structure I :and is loosely secured to the base member I2 bymeans of the screws 9. The mandrel 2I with the rotor elements I9 and .20 mounted thereon is next positioned between the side panels I3 Iand I4 with the teeth Iof the rotor elements extending between the pole faces of the field structure I8, it being pointed out that the length of the shaft portion Iof the mandrel 24 is substantially the same as the distance between the inner surfaces of the side panels I3 and I4 so that no appreciable :axial movement of the rotor elements is permit-ted. Following this voperation the shaft 22 with the gear 25 mounted thereon is inserted through the bearing carried by the side panel I4, through the mandrel 2I, and into the bearing carried by the side panel I3. The mandrel 2| is then secured to the shaft 22 by tight- 'ening the seti screw 24. The next operation is that of positioning the pole faces lof the field structure so that the teeth of the rotor elements I9 `and 20 are accurately centered between the slots defined by the respective oppositely disposed pole faces. To this end a suitable thickness gauge is insert-ed between the teeth I9a of the rotor element I9 :and the adjacent pole faces 58a of the eld member 59, and a second thickness gauge of equal thickness is inserted between the teeth 20a of the rotor element 20 Iand the pole faces 58s of the field member 59. Thus, by a proper selection of the thickness gauges used the teeth of .the rotor elements I9 and 20 may be accurately centered with respect to the associated pole faces of the field structure. Following this centering operation the screws 9 are tightened rigidly to secure the eld structure I8 to the base I2 of the supporting structure I0. The next assembly operation is that of mounting the spring pile 4l Iand its assembly upon the side panel I3, which operation will be obvious in view of the foregoing explanation. The driving mechanism :of the gener-ator is assembled by properly positioning the sleeve 3l longitudinally with respect to the bearing 21 with the gear 34 rigidly mounted thereon 'and the collar 38 loosely positioned thereon Vand thereafter tightening the set screw 39. Following this :assembly operation the shaft 26, with the crank 29 mounted thereon, is inserted through the sleeve 3|, the collar 30 and the collar 4:5 carrrying the disk 44. The two .collars 30 and 45' are now `properly positioned axially along the shaft 26, following which the set screws 39s and 46 are tightened rigidly to secure these elements to the shaft 26. The final assembly operation is that of securing th-e gears 33 and 32 upon the stub shaft 35 in mesh with the gears 25 and 34, respectively. To this end the gear combination comprising the two gears 32 and 33 is telescoped over the shaft 35 and the collar 36 is mounted on the shaft 35 in `abut/ting relation with the gear 32. Finally, the set screw 31 is tightened to secure the collar 36 to the shaft 35 and thus prevent axial movement of the gears 3'2 and 33.

In the operation of the device, and when the crank 29 is turned in a clockwise direction from the position shown in Fig. 1 of the drawings, power is transmitted through the elements 39 and 3l and the gear train comprising the gears 34, 33, 32 and 25 to the shaft 22 upon which the rotor elements I9 and 20 are mounted thereby to cause rotary movement of these elements. During the preliminary movement of the shaft zii/the inertia of the rotor assembly and the gear train together with the mechanical resistance of the gears and bearings more than offsets the bias exerted upon the end of the shaft 26 by the movable Contact spring 40. Accordingly, the engaged camming surfaces defined by the V- shaped notches formed in the sleeve 3I` and the -tapered ends rof the camming projections carried bythe collar 30, cooperate to cause the shaft 26 and the disk 44 carried thereby to be deflected to the left. During this longitudinal movement of the shaft 26 `the movable contact spring 49 is moved out of engagement with the spring 43 and into engagement with the spring 42. The longitudinal movement of the shaft 26 is limited through engagement of the straight sides of the camming projection 48 with the adjacent straight walls of the slots formed in the sleeve 3|. Thus, after a. small longitudinal movement of the shaft 26, the upper straight'side of the camming projection 48 is moved into engagement with the adjacent slot side 41s to establish a driving connection between the shaft 26 and the sleeve 3l. Substantially simultaneously the straight side of the other camming projection engages the adjacent side of the other slot formed in the sleeve 3|. Thus, it will be seen that the longitudinal or axial movement of the shaft 26 is limited and is positively arrested without frictional engagement between any of the moving parts of the driving mechanism and the supporting structure. After the direct drive connection between the shaft 26 and the sleeve 3I is'established, continued rotation of the shaft 26 is transmitted through the above described speed increasing gear train to the shaft 22, thus causing the teeth of the rotor elements I9 and 20 to be moved relative to the pole faces of the eld structure I8. During'this continued rotation of the rotor elements I9 and 20 and each time two of the teeth of the element 20 are moved into registration with the pole faces 58h of the field member 59, an obvious low reluctance path including-the leg 52h of the field member 52 is established. At this instant and as explained above, the Vteeth of the rotor element I9 are out of registration with the pole faces 58a of the field member 5S and the oppositely disposed pole faces of the leg 52s. Hence the reluctance of the magnetic circuit, including the leg 52a and the permanent magnet bar 53, is relatively high as compared to the reluctance of the flux path including the leg 52h. Accordingly, a predominant portion of the flux developed by the permanent magnet bar 53 is directed through the leg 52h of the field member 52. It will, of course, be appreciated that the flux traversing the leg 52h of the eld member '52 gradually increases each time .two teeth of the rotor element 2U are moved into registration with the pole faces 58h of the eld member 5i) and is gradually decreased as the two teeth are moved out of registration with these pole faces. In a similar manner, each time any pair of teeth of the rotor element I9 are moved into registration with the pole faces 58a of `the field member 59 the reluctance of 'the magnetic circuit including the leg 52s is gradually decreased so that Vthe flux traversing this leg of thei'leld structure is gradually increased, whereas, when the two teeth are moved out of registration with the indicated pole faces 58a the flux traversing the leg 52s is caused to decrease. Since the teeth of the rotor element i9 register with the slots of the rotor element 2li it will be apparent that an increase in the flux traversing the leg 52s of the eld structure is accompanied by a decrease in the flux traversing the leg 52a. and, conversely, an increase in the ux traversing the leg 52a of the field structure is accompanied by a decrease in the flux traversing the leg 52s. Due to the change in the fiux linking the respective windings I6 and l1 undulating or alternating voltages are developed in these windings. By connecting the windings in series aiding relation the sum of the voltages developed by the two windings may be impressed upon the output terminals, not shown, of the generator. This type of connection is employed when a high voltage, low current output is desired. Alternatively, the windings I5 and Il may be connected in parallel relationship to supply a low voltage, high current demand.

When rotation of the shaft is arrested and the crank 29 is released, the bias exerted by the movable spring lli! upon the disk 44 causes the shaft 26 to be returned to its axial normal position wherein the tapered ends of the projections of the collar nest in the V-shaped ends of the slots provided in the sleeve 3l. During such axial movement of the shaft 26 the movable' spring is moved out of engagement with its associated contact spring 2 and back into engagement with its associated contact spring 43. The contact springs 4LP, l2 and 43 may be utilized for any desired control purposes, although, in the application mentioned above, it is contemplated that these springs shall be used for the purpose of connecting and disconnecting the generator to and from the conductors of an associated telephone line and for the additional purpose of operatively associating the substation various modifications may be made therein, and

it is `intended in the appended claims to cover all such modifications as fall Within the true spir- `it and scope of the invention.

`What is claimed is:

l. In a magneto generator including a rotor, a drive shaft mounted for rotary and axial movement and a driving connection between said shaft and said rotor, a circuit controlling element operative in response to axial movement of said shaft, a pair of cooperating elements included in said driving connection, one of said elements being provided with a slot having parallel sides terminating in a substantially V-shaped camining surface, the other of said elements comprising a collar provided with a projection extending within said slot, said projection having sides extending parallel with but normally displaced from the parallel sides of said slot and terminating in a substantially V-shaped end to provide a camming surface which normally engages the camming surface of said slot, means including said camming surfaces for imparting axial movement to said shaft in response to rotation of said shaft, and means including said parallel sides of said slot and said projection for positively arresting axial movement of said shaft after a predetermined rotary movement of said shaft.

2. In a magneto generator including a rotor, a drive shaft mounted for rotary and axial movement and a driving connection, including a gear train, between said shaft and said rotor, a rotatable sleeve in Vwhich said shaft is journaled and having mounted thereon one of the gears of said gear train, said sleeve being provided with a slot havingparallel sides terminating in a substantially V-shaped camming surface, a collar mounted upon said shaft and provided with a projection extending within said slot, said projectionhaving sides extending parallel with but normally displaced from the parallel sides of said slot and terminating in a substantially V-shaped end to provide a camming surface which normally engages the camming surface of said slot, means including said camming surfaces for imparting axial .movement to said shaft in response to rotation of said shaft, and means including said parallel sides of said slot and said projection for positively arresting the axial movement of said shaft after a predetermined rotary movement of said shaft.

ELLIOTT H. OTTERBACHER.

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