US2596927A - Centrifugal machine control organization - Google Patents

Description

May 13, 1952 J. HERTRICH 2,596,927.

CENTRIFUGAL MACHINE CONTROL ORGANIZATION Filed June 20, 1947 2 SHEETS-SHEET l II VVENTOR. i/osepk flerir M y 13, 1952 J. HERTRICH 2,596,927

CENTRIFUGAL MACHINE CONTROL ORGANIZATION Filed Jun e 2Q, 1947 2' SHEETS-SHEET 2 TC new "3 I III .wwszvrox. Jose 9h Heriri c71 Patented May 13, 1952 CENTRIFUGAL MACHINE CONTROL ORGANIZATION Joseph Hertrich, Hamilton, Ohio, assignor to The Western States Machine Company, Hamilton,

Ohio, a corporation of Utah Application June 20, 1947, Serial No. 756,073

3 Claims. (Cl. 192-144) This invention relates to heavy centrifugal machines of the type used in sugar manufacture and more particularly to improved control combinations for high speed suspended centrifugals driven individually by rotary electric motors, such as A. C. induction motors.

An object of this invention is to provide an improved organization of a centrifugal machine driven by a rotary electric motor wherein the driving torque is transmitted through a slip coupling such as a centrifugal clutch, or preferably a hydraulic coupling, and wherein automatically and manually operated controls are provided such that the usual operations of loading, running and stopping the basket and spindle in each operating cycle, together with the desired process operations in the course of each running period, are brought about in the required manner and yet the driving motor normally is kept running at full speed throughout the successive cycles so as to increase the motor operating efflciency and reduce motor requirements and motor heating problems. I

Another object of this invention is to provide an improved organization giving the automatic control, the timing and the manual control of operations desired in the use of heavy centrifugals for sugar and similar processing work, wherein new combinations of elements motivated manually, electrically and by fluid pressure are utilized so as to secure the desired conditions .and movements of the apparatus with a relatively inexpensive construction which is easy to operate, easy to adjust to suit operating and processing needs, and foolproof under the conditions encountered in sugar centrifugal work.

This invention can make use of various known arrangements of driving motors with slip conplings to transmit the driving torque to the driven l elements of the machine, but it is preferred to utilize a driving combination. or system as disclosed and claimed in either or both of my United States Letters Patent No. 2,380,595 of July 31, 1945, and my copending application Serial No. 435,023 filed March 17, 1942, now United States Letters Patent N 0. 2,441,356.

A preferred embodiment is explained in the detailed description which follows, while the improved combinations claimed as this invention are set forth particularly in the appended claims. The description refers to the accompanying drawings, forming a part hereof, in which:

Fig. 1 is a diagrammatic front elevation, partly in section, of a high speed suspended centrifugal machine with its associated elements and controls;

Fig. 2 is a wiring diagram illustrating a suitable control circuit for the machine; and

Fig. 3 is a vertical longitudinal cross-section showing the torque control valve assembly as viewed approximately from line 33 of Fig. 1.

Referring first to Fig. 1 of the drawings, the centrifugal spindle 20 carries a perforate centrifugal basket 22 at its lower end within a surrounding stationary curb 23, and at its upper end the spindle is suspended within a suitable gyratory centrifugal head 24 supported from a suitable hanger 26 depending from framework (not shown). A motor support 30 on the same framework supports driving motor M which has a hollow rotor shaft 32 extending upward to a driving connection with the casing-impeller element 34 of a hydraulic coupling within housing 36 fixed atop the stator-carrying frame 38 of the driving motor. The runner 35 of the hydraulic coupling is disposed within the casing-impeller element 34 and is connected to the top of a central or driven shaft 33 which extends downwardly through the hollow motor shaft 32 to positive mechanical connections with the spindle 20 within head 24. These connections include a flexible coupling of any suitable type by which the spindle and basket are enabled to gyrate under unbalanced loads, in known manner.

A brake drum 52 on the spindle assembly cooperates withbrake bands 53 and 54 which are linked together and to the piston of a fluid pressure cylinder 55 in such manner that fluid under pressure admitted to this cylinder through air line 56 will set the brake bands tightly against the brake drum and bring the spindle assembly to rest from a running condition. .The brake bands normally are held away from the drum, in

brake off or unset position, in well-known manner. Line 56 is fitted with a three-way solenoid valve BSV which normally is positioned so as to vent pressure from cylinder 55, but which is moved to connect line 56 with a source 10 of compressed air or other pressure fluid, and thus cause setting of .the brake, when BSV is energized I electrically through connections hereinafter described.

slip between, the driving and the driven el'e-a ments and with the degree of filling, or oil content, of the hydraulic coupling.

The oil supply line 42 has therein a solenoid valve OSV which is normally closed so as to prevent oil flow into the hydraulic coupling. This oil solenoid valveopens when it is energized electrically as occurs through connection hereinafter described; When; it is closed with the motor running; ahyoil present in the hydraulic coupling becomes quickly discharged through the ports 3%, so that th'e torque transmission and driving action through the hydraulic coupling are thus discontinued.

A torque control valve G4 also can be provided the oil supply line for thepurpose of adjustany regulating the accelerating torque of the mach ne. This valve isnormally held open so as to stands free passage for the inlet oil from bra-rich "4211170 branch 42b of supply line 42, by mean or at mpression spring 46 or a fluid or hydraulic pressure system which urges the movable valve element 41 to valve open position under a constant control force. On the other hand, an arm it extends radially from the motor frame f3eandis positioned to engage the movable valve element and urge it toward closed position, inopposition to the control force, under the torque reactiono'f the motor M which isexerted byhavir' g the stator-carrying frame 38 mounted on r'n'otol' support w for limited turning move "ment The motor frame preferably is so mounted 'by m eans or a ci-rcular series of ball bearings 49 between it and thesupport 38 and by slightly enlarging the holesin the'frame through which bolt's; 5 0 extend to hold the motor to its support.

This torque, control system, which is described more "fully intl le aforesaid application Serial adjustable rate of; acceleration and brings about her QY IFQQ I I i s The apparatusfasshownis provided also with 'mejansjfor washing the centrifugal basket 22 or its contents *at appropriate times-in the centrifugal operatingbyoles and with means for separfating res ll ing. Wash liquid received on the wall of curb23 from liquid of different characteristi'cs centrifugedfrom the basket contents.-

The'se means per se are not a part of the invenbe eliminated from the basic control organization or may be arranged only for independent hand operation.

The washing means as shown comprise a sprayer'fi'fl of known construction extendingfrom a bracket 61 on the't'op of curb '23 downwardly into a position "within the confines of basket 22, and a pipe 62 through which hot water or other suitable washing fluid is delivered to the sprayer. This pipe is fitted with a solenoid valve WWSV, which normally is held closed so that the sprayer is off, but which opens to cause spraying or washing action when WWSV is energized electrically through connections hereinafter described.

The liquid or syrup separating means as shown is -the ,curbf or ring valve type disclosed in United States Reissue Patent 22,772 of Eugene Roberts. Annular partition as divides the bottom of curb '23 into inner and outer annular troughs. On the curb wall overlying the outer trough is an inclined annular ledge 65 upon whi'ch'a. vertically movable annular syrup deflector 66 may be seated. The inner portion of this deflector ring extends inwardly to overlie the top portion and inner side of. partition 64. When the deflector is sea-ted its outer edgeseals with ledge 65 to form an uninterrupted-syrupconducting platform extending from the inside of curb wall 23 iiito the inner trough. When, however, the deflector is raised, the said platform is interrupted to form an annular passage between the outer edge of deflector T55 and ledge 65, through which passage 'wash's'yrup brother liquid then flowing downthe c'urb wall is'entrapped into the outer trough.

The shifting of the deflector ring to its seated and its unseated positions, respectively, occurs through a series o'ffconne'ctions froin'tlie ring through the base of the bulb to the pistons' o'f air 'cylinders'fiii mounted on the exterior-of the curb. Only one of these several units "is shown. They normally hold ring 66 in its raises-or unseated position away from ledge 65, and they are connected to a fluid pressure line 69 through which compressed air or other suitable pressure fluid may be admitted to the cylinders eanoma three-way solenoid valve SS SV and compressed airline 1B. The valve S S/SV is arranged kllown manner so that it normally is open to transmit-compressed airinto line '69, thus holding thedeflect'or-ring 66 seated on ledge 65; while energization of valve "'SS STV through electrical connections hereinafter described closes'off the air pressure'a'nd connects line 5.! with; vent Tl so that springs in cylinders 63 the'n nlovethe defiector ring 65 to" its raised or unseat'ed position.

The "control of "the operations of the-machine is centered at a manually bperateds'With station 39 convenient to the 'centrifugalattendant. "In

the preferred embodiment; this switch station comprises a master switch and push -button units'PBl and P132; s V

V PBZ is a unit ofiwell-known construction'having two interlocked switches contro lled'by buttonstl and 82. Theses'witches are connected electrically wit ha control relayCRM which in turn is connected electrically with a motor starter 83 for connecting the driving. motor M p with its power "supply lines '8 41. comm n-electrical elements and connectionsjmay be employed such that u onuepiessim switch. button 81 a control-circuitis closed iii energizes relay CRM, which in turn energ zes the motor starter '83, an'd causes it to make j'motor' energizing connections betweelhfthe mot rfM and the power supply lines, 84. Upon depressing "pushb'utton 62 the motor Mfisdeenrgized' through aeeilergization of relay CRM and fstarterta.

V v Pushbfl'ttonfunit PBllikewise comprisesftwb interlocked switch elements positioned by/ buttons 85 and 86. These elements have electrical connections to one supply line I0! for control current and to conductors Hi) and III which may extend from a junction box JB. Conductor Hi! and the other control current supply line I02 lead from the junctionbox' to the washpushing of which terminates the washing or spraying action and causes the deflector ring to be reseated in sealing engagement with ledge 65.

The master switch MS is utilized for the control of the normal cycles of operation of the machine, and tothis end it has electrical actuating connections with the hydraulic coupling filling control device (oil solenoid valve OSV), with control device BSV of the brake setting means, and with adjustable electrical timing mechanism shown diagrammatically at T in Fig. 1. When desired, the washing and separator control devices WWSV and SSSV, respectively,

are connected through conductor branches Hila, Ilflb and Hid for actuations through contacts of the timing mechanism T which connect the respective branches to current supply line In],

so that all the operations in normal cycles of operation of the machine may take place in desired sequence in response to movements of the master switch MS.

Master switch MS is preferably a drum type switch of known construction having a rotary switch element or drum carrying contact segments and movable by a handle 90 which can assume several diiferent angular positions corresponding to different circuit conditions and difierent operating conditions of the machine. As shown, the switch has brake, off, load and .run positions at which the contact segments hold their respective circuits either open or closed as appears from the diagram in Fig. 2.

As there diagrammed the master switch segments include a wide drive control segment MR, shunted timer control segments MTI and MT2 and a narrow brake control segment MB.

Segment MR. is adapted to bridge contacts to connect control current supply line Nil with conductor I06. which leads through a normally closed contact GB! of control relay CR and through conductor liMa to the coil of solenoid valve OSV, the other. lead of this coil being connected with current supply line Hl2'so that valve OSV is energized and open when MB is active. j v

shunted master switch segments MT! and MTZ are adaptedto bridge contacts to connect line It! with conductor I05, which leads to the clutch coil TC of timer T and also through timer switch To (which closes with the energization of TC) to the timer motor TM. Since TC and TM are permanently connected with line 32, the closing movement of segments MT! and MT2 energizes and thus starts action of the timer, while opening movement of these The narrow master switch, segment 'MB is adapted to bridge contacts to connect line l0! with conductor I03 which leads to the coil of brake solenoid valve BSV; and since the other lead of this coil is connected to'line I02 the movements ofMB energize and deenergize, thus opening and closing, this valve.

In the off position of the master switch, as it appears in Fig. 2, all the master switch circuits are open. When handle is moved one step to the right to the Load position, the switch segments shift one step to the left, where segment MR closes its circuit from Ifll through H34, CR! and [Ma to OSV, and torque is then delivered through the hydraulic coupling from the running motorM to the spindle 29 to start the machine. The other master switch circuits remain open at this position.

When the master switch segments are moved two steps to the left from the "off position of Fig. 2, handle 90 in Fig. 1 being moved to the run position, segment MR makes the same drive activating circuit as above described, and at the same time segments MTI and MT2 make a timer activating circuit from NH through conductor I to the clutch coil TC and motor TM of the electrical timer T. At this position of'the master switch, therefore, the driving system is active to accelerate and run the basket and the timer is active. The timer then takes over the control of further operation in the normal cycle of the machine, as presently will be described.

Whenever the master switch handle 90 is moved to the brake position, the switch seg-= ments are positioned one stepto the right of their "oif position, so that the drive and timer control circuits are opened to inactivate the hydraulic coupling and reset the timer, while the brake is set because MB closes its circuit from line lill through I03 to open BSV. Air pressure then acts incylinder 55 to force brake bands 53 and E i against brake drum 52. Movement of the master switch to brake position thus pro vides for emergency stopping of the machine.

The timer mechanism T is an adjustable timing system comprising at least one timer switch element arranged to be moved at a predetermined time after the mechanism is activated, according to its setting, so as to discontinue the driving action upon the spindle and activate the brake setting means of the machine. Further timer switch elements also are included in the illustrated embodiment with connections to the washing and syrup separating means, respectively, whereby these means are actuated at adjustably predetermined times in relation to the starting of the timer mechanism and the concomitant starting of the acceleration or running period of the machine. The several timer switch elements may be provided by several interconnected individual. timers or time delay switches of known construction, or by a composite timer unit having a single motivating mechanism arranged to move the respective switch elements in adjustably timed relation to the starting or energization of said mechanism. The latter arrangement is preferred, and for this purpose a composite multi-switch unit of the type known as the Multiflex timer may be used; for example, a construction as shown in U. S. Patent No. 2,175,864.

Such a composite timer mechanism appears in Fig. 1. Its known construction (not shown in detail) includes clutch coil TC and timer motor TM of diagram Fig. 2, as well as the timer 7 motor switch To and, in this case, four individually timed switches T1, T2, T3, and'T L For each of these switches there'is an on detent and an ofi detent whichrespectively are adjustable in relation to a timing scale shown on the 'face of the unit so that a timed action or circuit change will occur at any desired interval in relation to the starting of'the mechanism, according to the setting of the respective detents. If the on detent is placed at the upper limit of its scale, the corresponding circuit or contact is closed when the timer is energized. If the off detent is placed at the lower limit of its scale, the corresponding circuit or contact-after having been closed according to they setting of the on detent, will stay closed until the timer is deenergized 'or reset.

According to the diagrams in Fig. 1 and Fig. 2,

the on detent of timer, switch To is placed at the top of its scale and this switch, located across conductor I85 leading to timer motor TM, is closed so that the timer motor becomes-active when the mechanism is energized through master switch segments MTI and MT2 (at the run position of themaster switch). The off detent of element To is placed slightly above the lowerlimit of its scale, say at 10 seconds less than a 5 minute setting, so that the timer mechanism inactivates its own-motor'if not reset after an abnormally long period-the normal period of timer activity being less than 4 minutes in the use here assumed by way of illustration.

Timer switch element TI is in the circuit from current supply line Ill-l to conductor 109, so that the closingof this element energizes relay CR.

-CR then opens its CRI contacts and closes its CR2 contacts with the result of discontinuing the driving action through the hydraulic coupling and setting thebrake to stop the rotation of the spindle assembly. Timer switch elements T3 and Ttare in thecircuits leading fromline Hll through branch conductors Ba and H01) respectively to conductor H and the coil of vaive 'WWSV, so that these timer elements may be closed independently toinitiate separate washing periods, and may be opened to terminate such periods. Timer switch element T2 isin the circuit from line ml to branch conductor Illa which leads to conductor HI and the coil of valve SS'SV, so that the closing and opening movements of element '1! result in energization and deenergization of the syrup separator control device SSSV with consequent raising and lowering, respectively, of the deflector ring 66.

To illustrate the timer settings, it-may be assumed that the machine is to be used for processing a sugar massecuite which is to be, subjected to apreliminary washing of about 10 seconds duration, to begin 15 seconds after starting the acceleration or running period-of the loaded centrifugal basket; followed '20 seconds later (45 seconds after starting) by a second washing period of 15 seconds duration; followed in turn by a drying periodof 'IO seconds at the end ofwhich the drying action is to be discontinued and, the brake set tostop the'machine. The syrupseparatoris to be unseated 5 seconds after starting the second washing period, sothat wash syrup received then and afterward on the curb-wall .23 will be collected in theouter troughv of the curb button. 7

I'm-such a'case, the on, *cletent-of-element TI is set on its scale-at a point corresponding to -2 minutes and 10 seconds, while the off detent isleft inactive at thebottom oithe scale; The

on detent of element T2 is set at a 50 second interval from the top of its scale, the corresponding off detent being placed at the bottom. The on and off detents of" element T3 are set at intervals of 15 and seconds respectively from the top of their scale, and the on and off" detents of element T4 are set at and second intervals respectively from the top of their scale. As has been described, the timer mechanism T is started in action by movement of master switch handle 9!] to its run .position. Element To closes at that time, while elements T3, T4, T2, and Ti close in sequence at predetermined times thereafter, according totthe-settingsof their respective on detents, and open at times determined by the settings of their. respective ofi detents.

The complete operation of the machine may be further described as follows:

When beginning the use of the machine after a shutdown period, button -8 l= of switch P32 is depressed to energize relay CRM and motor starter B3 and thus start the operation of the driving motor M, the master switch being at its off position so that OSV is deenergized, the hydraulic coupling is empty and. the motor runs freely without driving the machine.

Assuming the basket 22 to" be empty, the operator now moves themaster switchtoits load position andholds it. there .until the spindle-and basket have reached a low. speed. of. rotation desired for loading the basket,, which usually is about 200 B. P. M. This movement of the master switch closes the circuitliromline I0] through conductor I04, thenormally closed contact. OR! of relay CR and branch conductor I040. to the coil of OSV, so that oil flowsthroughO'SV and line 42 into the hydrauliccouplihg, filling the coupling and. causing the. motor. M'to transmit torque to the basket-carrying Y spindle.

Whenthe desired loading speed is reached, the operator may return. the master switch to off position and.v then load the basket in .the usual Way, or he may jog handle 90. between its load and off positionsto holda desired; loading speed, or he may move, handle 9.0 to its .run position and then start the l'oading'so that loading occurs in part of. the. accelerationperiod of the machine. The movement to. the runfiposition occurs, in any event, to start the acceleration or running periodof themachinelat which time the driving system .is activated, because master switch segment 'MR, closes.its circuit to 'OSV, and the timermechanism .is, activated ing cycle runs its course. vBy reason of the torque control system centered at valve 44, the acceleration takes. placeata constantrate under a constant accelerating torque that can be ad- .justed by adjustment of. the compression of spring 46.

At, an interval of 15 seconds. after movementfof the master, switch. to run position, the timer closes its switch element T3, which starts thefirst. washingv period by. energizing valve WWSV through branch conductor 0a and H0. Ten seconds. later. the. timer opens element T3, so that the first washing period ends. After another-20 seconds, the timer closes element T4 to start the second washing period, WWSV being then .energized through conductor H and. branch conductor! lflb. After another 5 seconds, or 50 seconds after starting the timer, the timer closes its switch element T2, which energizes SSSV through branch conductor Illa and conductor lll. Prior to this action, the syrup centrifuged from the contents of basket 22 has passed from curb wall 23 over ledge 65 and deflector 66 into the inner trough of the curb bottom, and the energization of SSSV causes the deflector to be raised so that wash syrup thereafter received on the curb wall flows between the ledge and the deflector into the other trough of the curb bottom.

The timer opens switch element T4 seconds after the shifting of the syrup separator, and the machine then proceeds on the drying phase of its cycle at its full running speed. This continues for '70 seconds, until 130 seconds after starting the running period, whereupon the timer closes its switch element TI to bring about the stopping of the basket. Thus OSV is deenergized, with the effect of discontinuing the driving action through the hydraulic coupling, and BSV is energized to admit compressed air from line 10 into line 56 and the brake setting cylinder 55, which applies the brake to stop the rotation of the spindle assembly. During all these operations, the driving motor M continues to run at full speed, pushbutton PBZ being left undisturbed throughout all the normal cycles of the machine.

The operator now returns to the machine and attends to discharging the processed sugar from basket 22 by moving master switch handle 98 to load position until the basket has reached a desired discharging speed and then manipulating a discharger (not shown) in the usual manner. Then the basket is brought again to the desired loading speed, and another charge is loaded to start another cycle which proceeds in the manner described above.

Sometimes it is desirable to clean the basket by washing it after the discharging operation, and for this purpose the operator may use buttons 85 and 86 of pushbutton unit PBI. Depressing button 85 starts operation of the sprayer and depressing button 86 terminates its operation.

If abnormal or emergency stopping of the basket is desired at any time during its rotation, the operator may simply move master switch lever 90 to the Brake position. This energizes BSV to set the brake and at the same time deenergizes relay CR and timer T so that the driving action through the hydraulic coupling is discontinued and the timer is reset to its starting position in the usual manner.

If abnormal or emergency stopping of the driving motor M is desired at any time, the operator may simply depress button 82 of PB2. A handle 51 is provided on the brake setting mechanism, so that the brake can be applied by hand at any desired time, in case failure occurs in the electrical control system.

It is to be understood that the detailed description and the accompanying drawings are illustrative and that the improvements herein disclosed may be embodied in various forms of construction within the scope of the appended claims.

I claim:

1. In a centrifugal machine comprising a basket-carrying spindle, rotary driving including an electric motor and a hydraulic coupling connected to transmit torque from said motor to said spindle, and a brake having brake setting means connected to stop rotation of said spindle, said brake setting means including an air cylinder, an air pressure line connected to said cylinder and a solenoid valve normally closing said line, motor switch means connected with and movable to energize and deenergize said motor, an oil supply line leading into said coupling having a solenoid valve normally closing said line, said coupling having means for continuously discharging oil therefrom, adjustable electrical timer mechanism comprising at least one switch moved at a predetermined time after the timer is activated, according to its setting, a master switch movable manually to different positions, electrical connections from said master switch to said oil solenoid valve and said timer mechanism, respectively, operative at one position of said master switch to open said valve and activate said time mechanism simultaneously, and electrical connections from said timer switch to said .oil solenoid valve and said air solenoid valve respectively, responsive to the timed movement of said timer switch to close said oil solenoid valveand open said air solenoid valve'simul- 'taneously, whereby after a predetermined period of running the machine the basket-carrying spindle is automatically stopped while the master switch is at said position and while the driving motor may continue energized and running.

2. In a centrifugal machine comprising a basket-carrying spindle, rotary driving means including an electric motor and a hydraulic coupling connected to transmit torque from said motor to said spindle, and a brake having brake setting means connected to stop rotation of said spindle, said brake setting means including an air cylinder, an air pressure line connected to said cylinder and a solenoid valve normally closing said line, motor switch means connected with and movable to energize and deenergize said motor, an oil supply line leading into said coupling having a solenoid valve normally closing said line, said coupling having means for continuously discharging oil therefrom, a torque control valve in said oil line having means for applying thereto a predetermined force tending to open the same, said motor having its stator-carrying frame mounted for limited turning movement and an arm extending from said frame to urge said torque control valve toward closed position according to the torque reaction of said motor, timer mechanism comprising at least one switch moved at a predetermined time after the timer is activated, according to its setting, a master switch movable manually to different positions, electrical connections from said master switch to said oil solenoid valve and said timer mechanism, respectively, operative at one position of said master switch to open said valve and activate said timer mechanism simultaneously, and electrical connections from said timer switch to said oil solenoid valve and said air solenoid valve respectively,.responsive to the timed movement of said timer switch to close said oil solenoid valve and open said air solenoid valve simultaneously, whereby after a predetermined period of running the machine the basket-carrying spindle is automatically stopped while the master switch is at said one position and while means l 1 the driving motor may continue energized and running.

3. In a centrifugal machine comprising a basket-carrying spindle, a rotary driving means including an electric motor and a hydraulic coupling connected to transmit torque from said motor to said spindle and a brake having brake setting means connected to stop rotation of said spindle, said brake setting means including an air cylinder, an air pressureline connected to said cylinder and a solenoid valve normally closing said line, motor switch means connected and movable to energize and deenergize said motor, an oil supply line leading into said coupling having a solenoid valve normally closing said line, said coupling having means for continuously discharging oil therefrom, adjustable electrical timer mechanism comprising at least one switch moved at a predetermined time after the timer is activated, according to its setting, a master switch movablemanually to several different positions, electrical connections from said master switch to said oil solenoid valve, said timing mechanism and said air solenoid valve, respectively, said master switch holding all said connections open at one position, at a second position closing connections only to open said oil solenoid valve, at a third position closing connections only to open said oil solenoid valve and activate said timer mechanism, and at a fourth position closing connections only to open said air solenoid valve, whereby while said motor isenergized said master switch may be moved manually to cause driving action upon the spindle through said coupling without action of the timer, or to run the machine with driving action upon'the spindle through the coupling and concurrent action ofthe timer, or

to discontinue the driving and timer actions and set-said brake, or to open all said connections so that the machine idles without driving, timer or brake action, and electrical connections from said timer'switch' to said oil solenoid valve and said air solenoid valve, respectively, interconnected with the aforesaid connections and responsive to the timed movement of said timer switch to close said oil solenoid valve and open said air solenoid valve simultaneously, whereby after a predetermined period of running the machine the basket carrying spindle is stopped while-the master switch is at said third one position and while the driving motor may continue energizing and running.

' JOSEPH I-IERTRICH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re;21,01 '7 Mellon Feb. 28, 1939 2,105,059 Steps Jan. 11, 1938' 2,227,077 Geldhof et al Dec. 31, 1940 2,250,453 Appel July 29, 1941 2,250,507 Thomas et a1. July 29, 1941 2,380,595 Hertrich' July 31, 1945 2,441,356 Hertrich May 11, 1948 2,466,989 Hertrich Apr. 12, 1949

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