US1531939A - Switch gear for controlling electric motors - Google Patents

Description

March 31. 1925 1 A v.L A. HlRsT E]- AL SWITCH GEAR `FOR CONTROLLING ELECTRIC MOTORS Filed Sept. 17. `1920 5 Sheets-Sheet 1 me?, s. @gw no .www www r fm nv; Mm JP.

'.J. A. HIRST ET Al.

SWITCH GEAR FOR CONTROLLING ELECTRIC MOTORS Filed sept. .1'1"l 1920 Y 5 sheets-sheet 2 March 31. 1925. 1,531,939

y v C Afa?.

March 3l. 1925. .,;':f731,939

J. A. HIRST ET AL SWITCH GEAR FOR GONTROLLING ELECTRIC MOTORS4 Percy m/' Brook,

March 31. 1925. ,531,939

J. A.-H|Rsjr ET AL SWITCH GEAR FOR CONTROLLING ELECTRTC MOTORS Filed Sept. 17. 1920 5 Sheets-Sheet 4.

//7 venons'.-

March 31. 1925. A 1,531,939

J. A. HIRST ET AL SWITCH GEAR FOR G'ONTROLLING ELECTRIC MOTORS Filed sept. 1v. 1920 5 sheets-sheet 5 Patented Mar. 31, 1925.

.UNITED STATES: PATENT @FFICE JOHN ARTHUR' HIRST AND PERCYSMITH BROOK', OF CHESTER, 'EhTGrIuhT).y

SWITCI-ILGEA'Rf-FOR CONTROLLING ELECTRIC MOTORSL Application filed September 17, 1.920. Serial'No. 410,976.

T0 all lwhom t mag/concern.'

Beit known that we, JOHN ARTHUR Hmsr and PERGY SMITH BROOK, subjects ofthe King of Great Britain, residing-inthe city and countywotl Chester, Fnglai'id, have invented'certain new and useful.Improvements in and Relating4 to SwitchGre'ar-s forControlling Electric Motors, of which thefol-r termediate position the. said control switch.l

isopened and the gear disconnected from the supplyY mazin, and such thatr the forward movemient 'ot the. handle-ds arrested-.when

the gear isA vin the iillon posit-ion; .the inveutionalso relates tothe construction arrangement .and connections ot a suitable orm` of drum.. type .electricmotor starter, particularly adapted for operation by a handle ol' the type described by which 4the angular movement imparted, step by '.step, to the drum is always in `the samedirection.

In the drawings: Fig.' l lis an elevation with the front plate'removedg Fig. 2 is a corresponding sideelevation in medial section.; Fig. is a fragmentary plan view; Fig. 4 is a side elevation partly iii sect-ion: Fig.. 5 is a 'liront elevation with the 1atchet removed.

Figs. .6 'and' areA views, similar' to Figs. l and 2;"Figs. 8 8A and 9 9A are explanatorydiagrams. .Figs 10 and 11 are difr agranis ot a modification.

F 12 is an elevation of a drum contro'ller, control switch and handle.; Fig. lf3 ,is a tragmentarysection of the end of Ythe drum; Figs. 13A, 13B are detail views ,of the iixed contacts; Fig.` 14- is-a perspective view, morer or less diagrammatic, ot 'the general arrangement of the gear; and Fig. l5 is a diagram. of connections. Y

Referring in the first instanceto Figs. 1 andQ andv 14:*

"1 is the lixedpart of the handle casing which is usually attached to the side of the iron-clad case A (see Fig; 12v) in which the gearing is enclosed: Ali'is a cylindrical l vce extension which forms a sleeve mounted so as to rotate about the casing; the handle .spindle 2 is `pivotally*mounted vin bea-rings lb' and l@ in the sleeve la, and the sleeve la,

e and spindle are located axially by the pinned* spindle l2 andexternal handle 2a attached thereto are together angularly movablerelatively to the tixedlpart of the casing, and about the Vaxis ot the latter. The handle Washer 2h.V

9.y is a. short hollow shaft journalledin the fixed part-ot the casing, which. shaft is adapted 4to operate the inainswitch gear, say vby the engagement of the: claw coupling part 3a with the rotating part-` ot the switch gear. On the shaft: Sai-e keyed ra ratchet 3b andan indicator 3C bearing the 'Words full-on, Which'words lWhen the gear is` in its full-on posit-ion, come .opposite a vwindow ld in the casing-1. Alpawl t adapted to en' vgage the ratchet 3b is pivoted on the bracket 2c carried from and rotatable ivithitlierotat-able sleeve ln of the` cas1ng,.and"to-andro movement of the handle and sleeve la impart a step by step movement to the s Shaft 3.

5 is an axially movable plunger tted Within the hollow shaft' andthe/insulated Y spherical end 5a of Which is adapted to. ac-

tu'ate acontiol switchin any convenient manner, sayby means of anaXially ymovable shaft- Within the rota-table part of. the main switch gear.

oWnaXis, say -by means of a cam piece 2d liXed on the spindle 2, or in any other suitable manner. V

In the arrangement illustrated the, ratchet 3b has eight teeth, and the limited angular movement of the handle andsleeve about eaterl the vaxis of the casing is somewhat gr than one eighth ot arevoliitiou. To-and-ro The plunger y5 has a head 5b` which 1s adapted to be moved b v the angular rmoverment of the handle spindleQ about ,itsy

lOl)

movement of the handle about the casing` axis therefore, by means of the nawl il, imparts a step by step rotational movement to the. shaft 3 which is transmitted to the gear to be operated by the claw coupling 3":

The handle is, as stated, also capable of limited angular movement about its own axis; the spring 20 normally turns the handle about its own axis to the position in which the am is clear of the head 5b of the plunger 5, which latter, or the axially movable shaft which it operates is controlled by a spring which presses it axially to the right. llhen the gear is operated, it necessary for the operator tirst to turn the handle about its own axis and so close the control switch, and then to oscillate the handle aboutl the axis of the casing. Oscillation about the axis of the casing without first having turned the handle about its own axis to operate the control switch, merely rotates the gear without closing the main circuit; and if the turning of the handle about its axis and the closing of the control switch is effected only afterthe first step of the main gear has been passed, the control switch is not ettective in closing the main circuit.

lhen the indicator 3c shows that the gear has been turned into its full-on position, the handle is released and the normal running position is maintained. A further step breaks the main circuit and returns the gear to the off position in which it is ready to be again operated.

It is desirable when the gear has been moved to the full-on position to arrest the forward movement of the handle 2 about the casing axis, and this may be etlected by electrically controlled locking means, or by mechanically controlled locking means. Figs. el; and 5 illustrate suitable electrically controlled means.

According to one modification of the invention the handle arrested when thc fullon position is reached by means af an electro-magnetically controlled detent lever which engages with a toothed wheel mounted on a part rotated by the handle, and which, when the appropriate angular position is reached is caused by the energizing of an electro-magnet to hold the said wheel against rotation; the said magnet being energized when the said position is reached, by the action of the switch gear in closing contacts arranged in a suitable energizing circuit. The arrangement in the device illustrated by way of example, is as follows is a toothed wheel which may be mountedon the shaft. 3 or the part of the gear rotated by the said shaft; for instance it may be mounted as shown in Fig. 12, on the drum of a drum type motor starter driven by the shaft 3. rthe wheel G, when direct-coupled to the shaft 3 has the same number of teeth as there are on the ratchet 3b; 7 is a detent lever pivoted at 7 controlled by a spring 7b and having a roller 7C which engages the spaces between the teeth of the wheel G and, by spring pressure on the roller is adapted to hold the switch gear in the successive positions into which it is turned by the handle gear. The detcnt lever is provided with an armature T which when a suitable electro-magnet 7@ is encrgized is pulled over and retains the lever in its engaging position. The switch gear is provided with contacts which are closed when the gear is in the full-on position, and the closing of which energizes the winding Tf of the magnet TQ. For instance, the con tacts 7g and 7 (Fig. l5) are closed when the gear is in full-on position and this connects the coil T f of the magnet 'l'e in series, with certain other energizing coils in a control circuit across the mains. The handle 2 is thus held fixed until the control circuit is opened by the usual press button provided for the purpose, or until the operation oit the no- Volt or overload devices.

A mode of mechanically arresting the forward movement of the handle 2 when the gear has been moved by successive steps to the full-on position is shown in Figs. (3 to 11.

According to this modification of the invention the surface of the tooth of the ratchet operated by the handle-driven pawl on which the said pawl rests when the fullon position has been reached, is made either higher or lower than the corresponding surfaces of the other teeth with the result that the pawl, when this stroke is being made, occupies a different angular position in relation to its pivot from that occupied when making the other strokes, and a stop is provided which engages and arrests the pawl before it completes this stroke; said stop being clear of the pawl whilst it is making the other strokes.

In the arrangement illustrated in Figs. (i, 7, S and f) the space o of the ratchet. 3" is made less in depth than the other spaces, so that after having made the stroke shown in full lines Fig. 8, which may turn the gear into its full-on position, the pawl 9 is, during the next stroke (the commencement of which is shown in chain dotted lines F S, and the. end of which is shown in full lines Fig. 9) held sufficiently high by the tooth 8 to ensure, before the stroke is coinpleted, the engagen'ient ot the locking piece 9 with the fixed stop lO carried from the lixed partl of the handle casing l. The arresting of the forward movement before the completion of the stroke indicates to the operator that the gear is in its full-on position which fact is also indicated by the indicator 3 coming opposite the window. The

halt Vstroke of the f gear completed before the handle isarrested may be usedto `turn the gear l:into the full-on position, or the latter position may be reached as described by the last full stroke, the halt stroke not altering the gear connections. On moving the handle back the next halt stroke will be made, and this turns the gear into the position'torstart-ing. The tooth 8 may be made. half the pitch of the other'teeth, and it desired the next tooth 8b in succession may be made half pitch also, soi-as to facilitate dividing when cutting.

In the modification illustrated in Figs. 10 and 11 the space 8 is `cutvmore deeply than the other'spaces, when thereforefthe forward stroke is being made, duringwhich the pawl.9 rests on the toot-h 81,-the engaging part ofthe pawl is delinitely arrested, before' the strokeI is completed, bythe Iixed stop 10. The construction a'nd =ac tion is similar to thatdescribedfin connection with Figs. 6, 7, 8 and 9, except. that the pawl is arrested inthelocking Vstroke because it is allowed by the deep space to take a positiony nearer the` axisv'ot rotation than that taken durin'g'the-other strokes, instead ot being held, during the--locking stroke,ffurther away from the saidaxis, by the shallow space, as in the-modication iirst described.

All the teeth including thosefopposite shallowor deep spaces may, in either fot the modifications described, be made of equal pitchif thefpawl movementfbe made,=say, slightly more than one and ahalt'tim'es the pitch-ofthe teeth and, the sporti-on of the locking stroke made before arrest is more than three quarters of the full stroke; this is shown -in Figs. 'SiL and 9a in which caseeit will be seen thatlatterf making three quarters of full stroke shown in tulllines, the pawl will be moved backto thefposition shown in chain dotted lines in which it engages the next tooth edge. f

The construction ofV locking arrangementmay, within the invention be modified in other ways; for instance,the shallowy or deep spaces may be cut in'an auxiliary ratchet, which auxiliary ratchetl may be operated by and cause the locking ot' the lmain pawl, oran auxiliarypawl may'beditted.

vThe handle mechanism comprising aL handle and spindle capable otreciprocating angular movement about the-.main raxisto operate the main gear,and ot limited rotary movement about its own axis, to operate a control switch, may beem'ployed with or without any of the locking-devices described, to operate any type of switch gear to which` a step-by-step movement, always in the same direction, has 7to-be im parted. `It may be applied for-instancey to switch gear ot the kind described -in the Specilication to Letters PatentNo. 1185324-,

Great Britain, 1920, granted to us. It is however specially applicable to a drum type motor jstarter, the contactsoli which are so arranged that it is moved 'from-the tall-on position to the ott position by angular Inovement in? the same direction as'that by which it -wasinoved vfrom the otlpositionto the full-onfposition, that is to say a drinn, the direction ot motion of which does nut need to be reversed to turn it from the full-on to the ott position.

A drum with connections so arranged is illustrated in Figs. 12 to 15.

:The construction and operation willbe best understood by describing tirst the diagrammatic viewFig. 14,.and the diagram of connections Fig. 15.

JB is .a handle` mechanism which rmay be of any ,type adapted to operatethe main gear with a step by vstep movement, which is constructed as above described in connectionwith Figs. 1 to 11.

f C is a drunipreferablymounted co-.axiallylwith the shaft 3 operated by thehandle as-described,and provided with a. central axiallymovable shaft 5c to which axial movement, inv opposition to a spring, is imparted by the plunger shaft 5 (sce Fig. 13).

`The handle and its-casing. and mechanism are completely vinsulated from ythe drum, the control switch and the live contacts. The shaft 5c is Iadapted by axial movement to` operate a control switch D.

11, v 12, 13, 14, 15, 16 and 17 are lixed contacts connected to thesectionally divided resistance R adapted to vbe put in series with theiarmature'E of the motor to be controlled, andill, 12', 13', 14, 15,.167and17 are contacts connected together .and mounted onithe Ldrumwand as the latterfis rotated step-by-step it successively cuts out the sections of the resistance andlinally,.in,its tullfonpositionfit short circuits the. resistance? R by connecting` the main contacts 11 n and' 12.

The mainsP and N are connected respectively4 to the'armature E and to the contact 11 through double pole isolating switches- 18 and circuit breakers 19, the latter being ot the electro-magnetic type held on by sole` with all the armature resistance R in circuit inchin Y switches 23 are fitted and a branch energizing circuit is carried through fixed contacts 23 and 22 to the inching switches; a contact 23 on the drinn connects 23 and 23h when, and only when the drinn is in the off position, so that in this position of the drinn the circuit breakers can be closed by closing one of the inching switches.

Vhen the drinn is, b v means of the handle turned into the first running position, and the handle is turned and the control switch D is closed, the energizing circuit is completed as follows From the negative main through the solenoids 19, the stop switches 2l, the overload switches 1.9, the shunt controller switch 22, the control switch D, contact Z1 to the drum main contacts, thence through the contacts 2li and the contact 2li which make contact, in the first running position only, to the positive main. The circuit breakers are thus closed, and in the second and subsequent running positions the control switch D connects the energizing circuit to the positive main through the drum contacts, the contact 11 and the wire 24. Should the handle be released in any of the running positions except the full-on position the control switch D is opened and the energizing circuit broken, whereupon the circuit breakers open. Then the drum is turned to the fullon position, a contact 7g on the drinn makes contact with a fixed contact 7 h, and the wire 7 short circuits the control switch D and the shunt regulator switch 22n when one is fitted, thus permitting the handle to be released and the control switch to be opened, the shunt regulator to be operated and the switch 22a to be opened without breaking the energizing circuit.

Then an elcetro-magnetic detent such as 7 is used to lock the gear in the full-on position, the winding Tf of the magnet 7" is connected in series with the wire 7", so that in the full-on position the detent 7 locks the switch gear as described.

rllhe motor is disconnected from the mains by opening one of the stop butt-on switches, after which the gear is turned by the operation of the handle to the off position in which position it is ready for the next operation.

Figs. 12 and 13 show a suitable construction of drinn type sta-rter. A is an iron-clad enclosing casing, B a handle of the type described; C the drinn carried in the bearings c1 and rotated by the hollow shaft 8 of the handle mechanism, the claw coupling 3 engaging with a suitable coupling c2 on the drum. The drinn is fitted with a concentric axially movable shaft 5c which is actuaated bythe insulating end 5 of the plunger shaft 5, which in turn is operated by the turning of the handle about its axis as described. The shaft 5C by axial movement operates the control switch D which is normally maintained open by the spring di", and which when closed, connects the cont-acts (Z1 and Z2 (see Figs. 12 and lll).

The drum carries the contacts ll to 17, 23, 2st, and 7g, all as described above, and the corresponding fixed contacts ll to 1.7, 2?, 214, and 7h are carried from a suitable base plate. rThe drinn also carries the toothed wheel G with which the electro-inagnetically operated detent lever 7 engages; the pivot of the lever 7 and the magnet 7c are carried from the base plate.

The fixed contacts are of the elastic yielding and renewable type and are constructed as shown in Figs. 13A and 13B.

The bracket 25 o'll pressed sheet metal bolted to the base by the terminal studs 25", and carries the pivot pin 26 of the finger 27, which is also of pressed sheet metal. The bracket 25, the bent plate 2S, the laniinated strip 34 and a covering plate 35 are riveted together and form an integral structure which is adapted to be secured to the base plate by the terminal screws 25u.

The contact 33 is detachably secured to the linger 27 by means of a stud 83, the head 33C of which is square in plan, and of dovetailed shape in profile, and fits a dovetailed recess in the contact 38 so that when the nut 33' is tightly screwed up with an intervening spring washer the contact 33 is rigidly secured in place on thc finger; the screw 33a is preferably turned from a bar of square section which enables the head to be formed as described; the head cannot rotatel in the contact and the contact is prevented from rotating by the flange of the finger 27 so that the nut 33 can be easily screwed up.

The finger 27 is slotted at 27"1 and through this slot extends a screw pin 8O carried from the fixed bent plate 28, and the spring 3l is interposed between the nut 32 and the washer 32L which latter rests against the. finger 27; the spring 3l therefore elastically presses the contact 3B on to the drum snrface.

then the contact 33 is worn by the amount represented in double cross hatching (Fig. 13b) further movement of the finger and contact towards the drinn arrested by the fixed plate 2S, but throughout any wear which may take place up to this limit constant elastic pressure is ensured by the adjustment of the nut 32.

29 is a spring secured Ato the fixed plate 2S by the pin this spring, by pressing against the flats of the nut retains the latter in its adjusted position.

The laminated strip 34 makes electrical contact with the finger by means of the bolt S-it and interposed spring washer.

llt)

QG is a distance ferrule surrounding the pin 26 and extending between the side cheeks of the linger 27 which latter fit between the side cheeks 25 of the bracket 25.

The drum, the circuit breakers, the circuit isolating switches and other live parts of the gear are enclosed in the casing A and the door of the casing is usually fitted with a switch a (see Figs. 14 and l5) inserted in the energizing' circuit 20 so that this circuit can be completed only when the door is closed, but of course this switch and such switches as the inching switches, the inching contacts 23', 23 and 23, and the shunt resistance switch 22a are not essential to the working' of the gear.

Having now fully described my invention I declare that what I claim and desire to secure by Letters Patent is l. In an improved handle mechanism for operating switch gear; in combination a ratchet mounted on a shaft connected to the main switch gear, a part capable of limited angular movement about the axis of the ratchet, a handle spindle mounted in bearings in said part so as to be capable of being' turned about its axis, a control switch,

an axially movable part adapted to operate the control switch, and to which part axial movement is imparted by the said turning movement of the handle, and means for automatically locking the movement of the shaft which operates the switch gear when the full on position is reached; substantially as described.

2. In a handle mechanism for operating switch gear, in combination:-a two part casing comprising` a fixed casing part and a movable casing part, a hollow shaft mounted in the said fixed casing part, main switch gear connected to said shaft, a ratchet keyed on said hollow shaft; an axially movable shaft mounted in the hollow shaft; a control switch actuated by said axially movable shaft, said movable casing part being mounted so as to be capable of axial movement about the centre of the hollow shaft; a handle the spindle of which is mounted in diametrically arranged bearings in the said movable casing a pawl carried from a bracket in the said movable part of the casing adapted to operate the ratchet and a cam carried by the handle spindle and adapted, when the latter is turned about its axis to operate the axially movable shaft; substantially as described.

3. In a handle mechanism constructed in accordance with claim l, the provision of an inter-tooth space on the ratchet of depth unequal to that of the other inter tooth spaces thereon, spaces, and a pawl adapted when it engages the said unequal space to be moved about its axis into a position in which it engages with a fixed stop and arrests the forward movement of the handle; 3

substantially as described.

In testimony whereof we affix our signatures in presence of two witnesses.

J OHl\T ARTHUR HIRST. PEROY SMITH BROOK. Witnesses to the signature of John Arthur Hirst:

JOSEPH E. Hins'r7 MARGUERITA JONES. Witnesses to the signature of Percy Smith Brook:

J. O. LLOYD BARNES, J osErH E. Hnzsr.

Images