US2478407A - Electric switching mechanism - Google Patents

Description

Aug. 9, 1949. R, LEAN 2,478,407

ELECTRIC SWITCHING MECHANISM Aug. 9, 1949. R, J, LEAN 2,478,407

ELECTRIC SWITCHING MECHANISM Filed Oct. 19, 1944 4 Sheets-Sheet 2 R. J. LEAN ELECTRIC SWITCHING MECHANISM Aug. 9, 1949.

4 Sheeis-Sheet 25 Filed oct. 19, 1944 llllllllllllllllllllIIIIHHHIllllllllllll l l'1 I u.

mz M Wm n M A M n@ aww@ Aug. 9, 1949. R'. J. LEAN 2,473,407

ELECTRIC SWITCHING MECHANISM Filed 061'.. 19, 1944 4 She-etS-Sheei'li Patented Aug. 9, 1949 UNITED STATES PATENT oFFlcE ELECTRIC SWITCHING MECHANISM Rodney James Lean, Erdington, Birmingham, England, assigner to Birlec Limited Application Gctober 19, 1944, Serial No. 559,370 In Great Britain October 22, 1943 a switch mechanism of robust and compact construction and to enable parts to be inspected, serviced and replaced easily and quickly.

In the drawings:

Fig. 1 is an end elevation of the mechanism of the present invention from within the casing;

Fig. 2 is a plan view from within the casing;

Fig. 3 is a front elevation of the mechanism within the casing with the casing cover open;

Fig. 4 is a detailed View of a mounting arrangement for the contact carrying levers and the linkage system therefor;

Fig. 5 is an elevation taken from behind the iront cover plate and showing the speed varying mechanism details; l

Fig. 6 is a rear elevation of the mechanism showing the gear train and auxiliary switch;

Fig. 7 is an end elevation of the mechanism showing the frictional drive detail.

The remote control mechanism shown in the accompanying drawings is housed in a casing I normally closed by a hinged cover 2 which is adapted to be retained in its closed position by a key-operated catch 3 carried in the said cover and adapted to engage behind a catch plate 4 mounted inside the casing.

The said mechanism is mounted within the casing upon a front frame 5 and a rear frame plate 6 held in parallel spaced relationship byrdistance pieces 'I carried upon the xing bolts 8. The front frame plate 5 is hinged upon a pin 9 (see Fig. 3) disposed within one end of the housing thereby enabling the mechanism assembly to be swung into and out of the casing for inspection, repair or the like.

Normally, the said assembly is held within the casing by a spring loaded catch I which is mounted within the top of the Casing so that it engages an edge of the front frame plate and, when the cover is closed, is located in its plateengaging position by a stud Il on the inside of the cover (see Fig. 1).

A switch-operating cam, comprising two concentric discs I2, I3, clamped together by screws Ila and each having four peripheral lobes I4, is fixed upon a main spindle I5 journalled in the plates 5 and 6. The spindle I5 is rotatable within its bearings in the frame plates 5, 6, drive being transmitted thereto from an electric motor 30,

9 Claims. (Ci. 20G-33) 2 the said motor spindle which meshes (see Fig. 2) with teeth on the periphery oi' a driving disc I3, a pair of balls I3, and two spaced parallel driven discs I8, I1. The driven disc I8 is ilxed to the main spindle I5, but the other driven disc I'I is slidable thereon and is urged towards the disc I3 lby a compression spring I5a (see Figs. 2 and '1),

to squeeze the balls I9 between the driving and driven discs I8-I6, I1 thus to transmit the drive from the driving disc I3 to the driven discs I8, I'I. The driving disc I3 is iixed on a lay spindle 20 which is also iournalled in the plates 5 and 8 (see Fig. 7) the balls I9 are rotatably housed in the ends of a bifurcated arm 2I iixed to a spindle 22 which is journalled in the frame plates and is provided at one end with an arm 23; the said arms 2| and 23, and the spindle 22, are assembled in the form of a bell crank lever (see Fig. 5).

The arm 23 is provided, at its free end, with a laterally extending roller 24 which bears against the edge of a control or speed varying cam 2l whereby, when the said cam is rotated, the bell crank lever is turned about its axis and causes the balls I9 radially to traverse the driving disc I8 and driven discs I8, I'I, for varying the speed at which the latter are rotated. The bifurcated arm 2I carrying the balls I9 is rotated by the driving disc in the direction which tends so to turn the bell crank lever that the roller 24 is held against the cam edge 25. This cam 25 is formed at one end of a sleeve 28 having an indicating disc 21 at its other end (see Fig. 1), the sleeve being fixed by a screw 28 to another spindle 29 joui-nailed between the frame plates 5, 6. Drive is adapted to be imparted to the spindle 29 from the motor 30 through a train of speed reducing gears terminating in the gear 3l keyed to the said spindle 29. The indicating disc is visible through a window 32 (see Fig. 1) in the cover 2 and is marked with a scale so that the position of the cam 25 may be indicated visually by a pointer 33 (see Fig. 3) also visible through the said Window.

The train of gears through which drive is transmitted to the spindle 29 consists, in addition to the terminating gear wheel, 3 I, of the gear wheels 34, 35, 35a, 36, 36a, 31, 31a and 38, 33a, drive being imparted to the gear train by the gear 3l which isilxed upon the spindle 20 whereon the driving disc I8 is keyed (see Figs. 2, Skand 7). The gear wheels 31 and 31a are fixed to a spindle 39 which is also journalled between the frame plates 5, 6 and is capable of both rotary and longitudinal movement therein (see Fig. 1); northrough the motor spindle 49, a gear wheel 43 on 65 mally the spindle 33 is held against longitudinal movementby a spring loadedbal'i 40, which is located wlthlnltnenousing na (see Fig. 1) and `engagesoneor other of the peripheral grooves 4I vand 4,2 in the sleeve 40h. The spindle 39 is caj pable of longitudinal movement through a stroke 5 equal to the-distance between the centresoi the vgrooves 4I and 42 and suiiicient to enable the gear `wheel 31 tobe taken out of mesh with the gear wheel 33a' vso that the drive from the motor 35 to the gear wheel 31 and cam 25 is broken `(see 1o Fig. 2); however, the said gear 'wheel l31 is provided with a toothed hub or gear 31a, which meshes with and transfers the drive to the next pinion 33 of the gear train and is o f such length l that its engagement with ythe said pinion 38 is 15 not broken by the longitudinal movement of the spindle 33. 'I'he grooved sleeve 40h is mounted A freely on the spindle 39 and is secured to a button 44 by the thread 45. j The button 44 projects through an aperture 41a in the cover 2 and is provided internally with an axial stud` 44a (see Fig. vl.) which abuts the end of the spindle 39 and is adapted to impart longitudinal motion to the said spindle, for taking the spring loaded ball 40 out ofengagement with the peripheral 25 singing elongated openings in the sleeve 40h'. 3g

Such rotary motion enables any desired setting to be lgiven to the speed-varying cam before the mechanism is started or at any stage in the subf sequent cycle of operations to venable the driven discs I3, I1, and the switch operating cam I2, o

I3, to be rotated at a denite speed. This speed may be maintained by allowing the gears a and 31 to remain disconnected, or may be increased gradually by pulling the button to re-engage the said gears with one another so that the motor 45 drive may again be imparted to the cam spindle 23. If re-engagemen't of'the said gears is attempted when their teeth are wholly orpartially overlapping, the pull imparted to the button 44 displaces the sleeve 40h along the spindle 39 and 50 compresses the spring 34h. A silent re-engagement of the gears is, therefore, made automatically by the spring when relative movement occurs between the gears 36a. and 31.

Two adjustable xed contacts 53, 5I (see Fig. 55

3) assembled to insulating terminal blocks 52, are mounted upon the front frame plate 5 whilst complementary moving contacts 53, 54, are carried by the levers and 53 respectively. Each of the said moving contacts is provided with a conductor 51 vwhich electrically connects the complementary moving contact to its terminal 5B carried in and insulated from the said frame plate. Each contact-carrying lever 55, 56 is rotatably carried upon a shaft 50 having eccentric end pins 50a journalled in a bracket 59 which is fixed to the said front frame plate 5 by screws 59a and one end of which serves as the pointer 33; the two shafts 60 are coupled together by linkage system 6I, 62, vSil, whereby any .motion 70 imparted -to one of the said eccentrically journalled shafts is transferred to the other; the arrangement is such that the rotation of the shafts 50 varies the gap between the ilxed and moving being increased landthe space between the other pair being decreased. The levers 55, 55, are

formed respectively with tail pieces 34, 35, each being provided with an ear 83 which is urged towards the periphery ot twin switch-operating .cam I2, I3, by a spring 51, which also tends to displace the complementary moving contact towards its fixed contact.

A phase-adjusting cam disc 63 is also ilxed to the main spindle I5 concentrically with the switch operating cam I2. I3. A lever 69 is hinged on an l adjustable bell-crank bracket 10 clamped to the front frame plate 5 and the said lbracket is loaded by a spring 1I. The free end of the lever 69 is urged against the phase-adjusting cam 33 by the inherent resiliency of a flexible moving contact carrying blade 12. When the bracket 10 is releasedv by loosening the screw 10b it may be angularly adjusted by the turning of the eccentric stud 10a, thereby altering the times in the cycle of operations when the lever will ride oi the lobes 63a of the phase adjusting cam 33. The moving contact carrying blade 12 is located between resilient contacts 13, 14, and is disposed centrally and clear of said contacts 13, 14, when thelever 69 is half-way along a cam lobe 38a; hence the flex- -ing of .the `blade 12 makes and breaks the connection with the said. resilient contacts. The A resilient contacts 13, 14 are electrically connected 30 respectively in the circuits of the coils 15 and 1E, the coil 15 being adapted to be energised when the moving contact of the lever 39 raises the blade 12 and the coil 16 being adapted to be energised when the said lever allowslthe blade 12 to ilex downwardly. An armature 11, carried on the frame plate 5 between an over-centre spring 13 and a lever 19 connected to the linkage system 6I, 62, 63, is adapted to be attracted by either coil, when energised to angularly displace the eccentrically mounted shafts 30. The coils are .r'zgnnected in parallel, through the-contacts 13,

The mechanism also comprises a manually operated switch 80 which is mounted in the cover (see Fig. 2) and is adapted to close the circuit of the motor 30 directly when in one position, or

' through an auxiliary switch 8i when in its'other position. The moving contact carrying member 83 of the auxiliary switch 8| bears reslliently on the surface of a slotted roller 82, composed of insulating material, which is keyed to the main cam spindle I5, and is so located relatively to the switch-ioperating cam I2, I 3, that the member 83 engages a slot 84 on roller 82 when one of the lever ears is at the centre of a lobe i4. Thus when the motor is started, with the switch 8!! in the position shown in Figure 2, the motor continues to run until a slot 8d on the roller 82 registers with the moving contact carrying blade 83 of the auxiliary switch 8l. The blade 83 thereupon enters the slot 84 and opens the said auxiliary switch so breaking the motor circuit and bringing the mechanism to rest with one of the lever ears 66 located -midway along a lobe I4 of switch operating cam I2, I3. The switch mechanism described above is particularly suitable for controlling the variable oscillations of a rocking furnace so that the furnace shell may be rocked through equal angular distances to each side of a dead centre position and so that, if desired, the said angular distances may gradually be increased to, and maintained at, a maximum.

For this purpose, there is mounted on the furcontacts, the space between one pair of contacts nace structure a limit switch (not shown in the drawings, and not forming a part of the present invention) which is closed by the furnace shell each time the latter reaches or passes through its dead centre position; the contacts 13 and 14 of the coils 15 and 15 are connected to the said limit switch so that an electrical impulse is fed through one or other of the said coils each time the limit switch is closed.

The furnace shell is adapted to be rocked automatically by a reversible electric motor under the control of reversing contacter switches actuated by the pairs of contacts 50, 53 and 5I, 54; also, by the manual actuation of push button controis (which contacter switches, motor and push button controls, again are not shown in the drawings and do not form a part of the present in vention) the shell-rocking motor may be started and stopped at will to set the furnace shell in, or substantially in, its dead-centre position prior to-the commencement of the rocking operation under the control of the said contacter switches and the said two pairs of contacts.

Having brought the switch mechanism of the invention to rest with one of the lever ears 66 located mid-way along a lobe i4 of the switchoperating cam l2, I3, and having set the furnace shell in its dead-centre position, the switch 80 is changed over to connect the circuit of the motor 30 through the auxiliary switch 8i whereupon the said motor 30 and the shell-rocking motor may be started simultaneously with the furnace shell rocking in phase, or substantially in phase, with the levers 55 and Sii, and the phase control means operated by the switch 12, 1.1, 14.

As the dual switch-operating cam l2, I3, rotates, it causes the pairs of contacts 50, 53, and 5l, 54, to open and close alternately; the closing of one pair of contacts actuates a complementary contactor switch to drive the shell-rocking motor and the furnace shell in one direction, and the closing of the other pair of contacts actuates another contacter switch to reverse the said motor and the direction of travel of the furnace shell. The arrangement of the lobes of the said cam I2, I3, is such that a dwell exists between the opening of either pair of contacts and the closing of the other pair, during which dwell the shellrocking motor, the furnace shell and the ccntents of the latter come to rest before the reversal of movement commences, thereby reducing strain on the said motor and any gear through which drive is transmitted to the said shell. This cycle of operations continues under the control of the switch mechanism of which the cam I2, i3, and contacts 5G, 53 and 5i, 54, form parts.

The angular distance through which the furnace moves is determined by thespeed at which the cam I2, I3, rotates since this speed determines the period during which a pair of contacts remains closed.

At the commencement of the cycle of operations, the speed varying cam 25 is set so that the balls i9 are disposed near the periphery of the driving disc I8 and near the centre of the driven discs It, I1. The latter and, therefore,

the cam I2, I3, are thus driven at maximum V Thus the speed of the driven discs I6, I1, gradualiy falls, the closing period of the contacts 50i, 53, and 5I, 54, increases and consequently the angular rock of the furnaces increases.

If it is desired that the furnace should reach and maintain a predetermined maximum angular movement, the button 44 is depressed when this movement is attained, thereby breaking the drive to the cam 25 by disengaging the gears 36a and 31. Also, if it is desired that the furnace should rock through a predetermined angle at the commencement of the cycle of operations, the drive to the cam is again broken and the cam 25 is rotated manually by the button 44 and gears 31a, 38, 38a, and 3I, until the desired position, in-

dicated by the pointer 33 and the indicating disc 21, is attained.

Should the furnace shell continue to rock outof-phase, that is through a greater angular distance toone side of its dead-center position than to the other side, the electrical impulse which is transmitted through the switch 12, 13, 14, and one or other of the coils 15, 16, by the closing of the limit switch operated by the furnace as it passes the dead centre position, flows when the moving Contact 12 is in connection with one or other of the contacts 13 or 14. This occurs because the said moving contact is only in its central position', which ensures that both coil circuits are open, when the lever SS is half-way down the-steep face 68h of, or half-way along the slightly inclined face of a lobe 68a of the phase-adjusting cam 68. Further these intermediate positions are assured only when one of the lever ears 66 is at a central or substantially central position along a lobe it of the switchoperating cam I2, I3, that is, when the furnace is half-way between its two extreme positions. Thus, if intermediate positions are not assumed simultaneously, as when the furnace is rocking out-o-f-phase, the electrical impulse is able to energise a coil 15, 16. The energised coil attracts `the armature 18 thereby angularly displacing,

through the lever 19, the eccentrically journalled shaft 6G on which the lever B4 is mounted. This angular movement is transmitted through the links 6I, B2, and B3, to the shaft carrying the lever 55. These angular movements of the shafts 60 cause the hubs of the complementary levers to be displaced so that the moving contacts and the ears 66 tend to move nearer to or further away from the fixed contacts and the operating cam I2, I3, respectively. If the pairs of contacts 50, 53, or 5l, 54, are closed, movement will be imparted to the ears so that the latter will meet the steep face of a lobe I4 earlier or later in the cycle of operations. If the contacts are open then the ears are in contact with lobes l-'l and the movement will be transferred to the moving contacts causing them to move nearer to or further away from their complementary xed contacts. No matter whether the movment is transferred to the ears of the moving contacts, the result is that the relative periods of opening and closing of the pairs of contacts are altered so that the time during which the furnace travels in one direction is altered at the expense of the time available for it to rock in the reverse direction, since, owing to the arrangement of the eccentric studs BU and the linkage system 6I, 62, 63, the lever hubs are moved so that there is an increase in the time during which one pair of contacts is closed and adecrease in the time during which the other pair of contacts is closed. Thus when the coil 15 is energised there is an increase in the period during which the contacts 50, 53, are closed and a decrease ln the period of closing of the contacts I, 54; on the other hand, if the coil 18 is energised the closing period of the contacts 50, 53, is decreased and the closing period of the contacts 5l, 54, is increased.

In order that the operation of the armature may be more delicate and sensitive, the amature 11 and lever 'I9 are counterbalanced by a weight The time taken for the angle of rock of the furnace to reach its maximum depends upon either the shape or the rate of rotation of the speed varying cam 25 and may be altered by replacing, for example, two of the gears of the gear train. To enable such a change to be eiected quickly and easily, the gear wheels 3l and 38a rotating said cam, control means connected to be i driven by the drive means and operative automatically to vary the speed of said rotation, pivotal levers carrying the moving contact of each of said pairs and adapted for actuation by said lobes during said rotation whereby said circuits are opened and closed in a predetermined sequence determined by the shape of said lobes, and ancillary means for varying the relative periods of said actuation.

2. A remote control switch comprising at least two pairs of electric contacts each pair consisting of a xed contact and a movable contact and each pair being connected in a separate circuit, a separate pivotal lever carrying the movable contact for each of said pairs, a separate eccentrically-journalled lever spindle for each of said levers, tensioning means on each of said levers normally adapted to maintain said movable contacts in closed-circuit relationship with the xed contact of its pair, a substantially circular rotatable cam having a plurality of lobes on the periphery thereof adapted to overcome said tensioning means and to actuate said levers in alternating sequence during rotation of said cam whereby said circuits are opened in alternating sequence, a cam-spindle carrying said cam, variable speed rotating means for said cam-spindle, a linkage system interconnecting said eccentrica]- ly-J'ournalled lever spindles for transmitting rotary motion from one to the other thereof thereby to vary the relative periods of said actuations, and means for transmitting rotary motion to one of said lever spindles.

3. A remote control switch as in claim 2 in which the means for transmitting rotary motion to one of said lever spindles comprises a pair of solenoids, an armature rotatably carried on one of said lever spindles and having an end projecting between said solenoids adaptedy for attraction thereto on energization of said solenoids, l and meansfor intermittently energizing said solenoids whereby said armature is attracted to said energized solenoid thereby transmitting rotary motion to said lever spindle.

f 4. A remote control vswitch comprising cam actuated means for opening and closing a plurality of circuits in a sequence determined by the shape oi' the cam, drive means for rotating the cam, control means operative automatically and progressively to vary the speed of the cam rotation, and disconnectable means for driving the control means in' synchronism with the cam drive means.

5. A remote control switch comprising cam actuated means for opening and closing a plurality of circuits in a sequence determined by the shape of the cam, drive means for rotating the cam, control means operative automatically and progressively to vary the speed of the cam rotation, disconnectable means for driving the control means in synchronism with the cam drive means, opposed magnet coils and armature means actuated alternatively by the coils and connected to reversely vary the relative periods during which the circuits 'are closed at any given speed of rotation.

6. A remote control switch comprising cam actuated means for opening and closing a plurality of circuits in a sequence determined by the shape of the cam, adjustable position drive means for rotating the cam at varying speeds, control cam means operative automatically and progressively to vary the position of the cam drive means to vary the speed of the cam rotation, disconnectable means for driving the control means in synchronism with the cam drive means. opposed magnet coils and armature means actuated alternatively by the coils and connected to reversely vary the relative periods during which the circuits are closed at any given speed of rotation, a manually operated starting switch and means associated therewith and operative to open the circuit at a given position of the circuit actuating cam.

7. A remote control switch comprising cam actuated switch means for opening and closing a plurality of circuits in a sequence determined by the shape of the cam, adjustable position drive means for rotating the cam at varying speeds, control cam means operative automatically and progressively to vary the position of the cam drive means to vary the speed of the cam rotation, an indicator disc connected to the control means, disconnectable means for driving the control cam means in synchronism with the cam drive means and a push button connected to eiect manual disconnecting ofthe automatic control means and connected to permit manual adjustment of the drive means.

8. A remote control switch comprising cam actuated switch means for opening and closing va plurality of circuits in a sequence determined by the shape of the cam, adjustable position drive means for rotating the cam at varying speeds, control cam means operative automatically and progressively to vary the position of the cam drive means to vary the speed of the cam rotation, an indicator disc connected to the control means, disconnectable means for driving the control cam means in synchronism with the ca-m drive means and a push button connected to eiect manual disconnecting of the automatic control means and connected to permit manual adjustment of the drive means, and a manually operable starting switch and means associated therewith and operative to open the circuit at a given position of the circuit actuating cam.

9. A remotecontrol switch comprising cam actuated switch means for opening and closing a plurality of circuits inl a sequence determined by the shape of the cam, adjustable position drive means for rotating the cam at varying speeds, control means operative automatically and progressively to vary the position of the cam drive means to vary the speed of the cam rotation, an indicator disc connected to the control means. disconnectable means for driving the control means in synchronism with the cam drive means, means to eiect manual disconnection of the automatic control means -and connected to eiect manual adjustment of the drive means, opposed magnet coils and amature means actuated alternatively by the coils and connected to reverselv l0 REFERENCES omni The following referenloes are of record in the 111e of this patent:

UNITED STATES PATENTS Number Name Date 933,217 Wood Sept. 7, 1909 1,156,610 Meyers Oct. 12, 1915 1,710,367 Luczak Apr. 23, 1929 10 1,779,919 Shoemaker oct. 2s, 1930 2,234,375 Kronmilier Mar. 11, 1941 vary the relative periods during which the cir- 15 cuits are closed at any given speed of rotation.

' RODNEY JAMES LEAN.

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