US918574A - Air-cleaning system. - Google Patents

Description

W. MAYO z J. HOULEHAN.

AIR CLEANING SYSTEM.

APPLICATION FILED IEB.24,1908.

Patented Apr. 20, 1909.

3 SHEETS-SHEET 1.

SH01 mma W. C. MAYO & T` HOULEHAN.

AIR CLEANING SYSTEM.

APPLICATION FILED 111313.24, 1908.

91 8,574. Patented Apr. 20, 1909.

3 SHEETS-SHBET 2.

./ y f3] j JJ y 59 jy W. 0. MAYO al J. HOULEHAN.

AIR CLEANING SYSTEM. APPLICATION FILED PBB.24,1908.

Patented Apr. 20, 1909.

3 SHEETS-SHEET lt.

UNITED STATES PATENT OFFICE.

`WILLIAM C. MAYO .MND JOHl\v llOL'LIllAN, Ol" l'lL PASO, TEXAS, ASSIGNORS O1l` ONE-THIRD T() GEORGE l. Bltllit, OF BAltSTOi/V, TEXAS.

AIR-CLEANING SYSTEM.

Application filed February 24, 1908.

Specification of Letters Patent.

Patented April 20, 1909.

Serial No. 417,382.

El Paso, State of Texas, have invented a new and useful Air-Cleaning System, of which the following is a specification.

This invention has reference to improvements in air cleaning systcmsdesigned more particularly for use in dwellings or in other places where it is advantageous to have the air-cleaning mechanism in small units which may be readilymoved from room to room and which may be made in domestic sizes.

The present invention is directed more particularly to the air pump and driving means `therefor to operate in conjunction with a suitable tank and cleaning head, the tank serving both as an air reservoir and as a means for separating the dust and dirt collected by the current of air from said air current so that the same air may be again used for the pump.

The present invention comprises an air pump together' with a motor for driving it, which motor is preferably in the form of an electrically driven motor, although not necessarily confined thereto. ln the case of single phase and other induction motors having a low starting torquev )revision is made whereby the motor will a ways reach approximately 'full speed before it is coupled up to the pumps, and again should there be ari-over-load tending to abnormally'reduce the speed of the motor, then this over-load, due to accumulated pressure in the tank, will disconnect the pumps from the rotor of the motor so that the. motor is neither overloaded on startingr nor can it be overloaded after having attained its speed. Consequently, there is no danger of burning out either the field or armature of any type of motor liable to such'accidents, even though the motor be under the direction and control of a person ignorant of the management ofy an electric motor. These features are particularly advantageous in connection with the system under consideration since the cleaning apparatus is designed for use in dwellings and other places where it is to be used by doinestics and other help unskilled in the management of electric apparatus.

The particular type of electric motor is not essential to the present invention but may be either of the alternating current type or of the continuous current type, according to the current available for its operation.

' Because of the conditions under which the apparatus is to be used it is made entirely automatic so that the operator has but to turn an electric switch to start or stop the apparatus while the running will require no attention whatsoever during indefinite periods of time. In order to permit the motor to run up to speed before the load is placed upon it, provlsion 1s made for operating a friction c utch between the motor and the pump so that the friction clutch members are held out of operation until the speed closely approaches the maximum speed. when the friction members are permitted to engage and will remain so engaged until the motor is nearly or quite stop ed. The capacity of the reservoir but litt e exceeds the .demand for com ressed air, and the pumps are made to wor with but little clearance. Under these conditions should the air outlet to the reservoir be suddenly closed the pump w ill tend to enormously increase the pressure. This of course means a heavy load u on the motor with the consequent slowing c own of the same. ln the case of the induction motor there is a rush of current through the fields due to the reduction of the counter electro motive force when the armature slows down, resulting in the burning out of the fields and the possible injury to the squirrel cage of the armature. ln the continuous current motor the rush of current under similar conditions results in the burning out of the armature.

ln the present invention an increase of air pressure above a certain predetermined maximum reacts upon the clutch mechanism to pullone member away from the other and thus cut out the pump until the pressure is again reduced, and this is accom lished I without in any way aiiecting the spee of the motor, so that in the case of the single phase motor it is not pulled out of synchronism with the current.

The invention will be. best understood by a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, in which drawings,-

Figure 1 is a section, partially in elevation, of the improved pumping mechanism. Fig. 2 is a section through the pump cylinders at right angles to the section of Fig. 1, with someparts'in elevation and other parts omitted." Fig. 3 is a detail view of a modified form of the mounting for the pump-driving cams. Fig. 4 is an elevation of the complete structure somewhat diagrammatically illustrated. y

Referring to the drawings, andmore particularly to Figs. 1 and 2, there is shown two pump cylinders 1--2 formed in one casting and connected by brackets 3 to an end plate 4 of the motor casing, .to be described. Formed on the plate 4 are other brackets 5-6 above the pumps which serve to support the journals of a shaft 7- carrying the means for driving the pum pistons, as will presently appear. The sha t 7 is threaded at each end, as shown at 8 9, and upon the threaded ends are two cone collars 10-11. At the intermediate portion of the shaft there is also a threaded section 12, at each end of which is formed an annular cone shoulder 13 and 14, respectively. Surrounding the shaft 7 between the cones 10 and 13 is a collar 15 having annular end recesses 16, which recesses coact with the cone faces ofthe cones 10 and 13 to constitute ball races for a series of anti-friction balls 17. Surrounding the shaft between the collars 11 and 14 is a collar 18 having annular end recesses or grooves 19 co-acting with the conical faces of the cones 11 and 14 to form ball races for the series of antifriction balls 20. The sleeves 15 and 18 are housed in suitable heads 21 formed on the respective brackets 5 and 6.

Fast upon the intermediate threaded portion 12 of the shaft 7 is a large worm wheel 22 in mesh with and driven by a worm 23, on a drive-shaft 24 to be referred to.

Mounted eccentrically upon the threaded ends 8 and 9 of the shaft 7 are two eccentric heads 25 connected to pitmen 26, each of which is journaled by a pin'27 to a piston 28 of the ordinary trunk type, which piston has a suitable number of packing ringsV 29 and is made to lit in the cylinder 1 or 2, as the case ma be. Each eccentric 25 consists of a dis 3() having an annular conical shoulder 31 beyond which the disk is formed with a radial flange 32. Matching the disk 30 u to the shouldered portion thereof, is anotfier disk 33 having a peripherally beveled shoulder 34, and outside of this last-named disk is a face-plate 35 of the?y same diameter as the outslde diameter of the radial flange 32 of the disk 30. Between the iiange 32 and plate 35 there is housed an eccentric strap 36 formed on the end of the pitman 26. The shoulders 31 and 34, together with the strap 36, coact to form a ball-race for a series of anti-friction balls 37. Between the plates 30 and 33 are a number of laminas 38 of paper or other suitable material which, as the parts wear, may be removed sheet by sheet to permit the taking up of the wear.

The shaft end 8 or 9, as the case may be,

shaft is counterbored in the disk 30 to form y a seat for the cone 10, and a nut 39 applied exterior to the plate 35 serves to clamp the structure firmly to the shaft. In order that the parts may be held together without danger of spreading, a bolt 40 is passed through the plates or disks 33 and 35, and is threaded into the disk 30. This bolt is located at a point diametrically opposite the shaft and equidistant from the center of the respective cam-heads. It will be observed that the right hand end of the shaft 7, as viewed in Fig. 2, is made smaller than the left hand end, and the cones are likewise smaller. This is for the purpose of assing the shaft through the bearing in the racket 5 and through the worm wheel 22.

It will be seen from an inspection of Fig. 2' that all the moving parts between the shaft and its bearings and between the shaft and the pitmen move upon balls so that the several arts are all provided with antifriction earings, and while there is practically no power consumed in these bearings they have the further advantage of requiring ver infrequent attention, and by using the ordinary rubbing bearings are provided and ball bearings are omitted. In each bracket 5 or 6 a sleeve 41 of brass or phosphor bronze or Babbitt metal is introduced etween the bracket and the shaft and may be confined in place by a loose collar or washer 42. The disk or plate 30 is replaced by a thicker disk 43 provided on one side with a radial peripheral flange 44 between which and the face late 45 is confined aring 46 of some suita le metal, such as namedwith respect to the sleeve 41. Exterior to this ring -46 is the eccentric strap 36, as before.

The valve structure for each cylinder is shown in Fig. 1. Below each iston and in A.the saine casting with the cylinder there is '/f'formed an intake chamber 47 and an outlet chamber 48. The inlet chamber 47 communicates with the bottom of the respective cylinder through a passage 49, and in this assage is the hollow stein of a plug 5() formed at its upper end into a valve seat 51, and having its walls provided with numerous perforations 52. .In operative relation to the valve seat 51 is a valve 53 in the form of a cup seated in a suitable socket formed in the casing below the bottom of the cylinder, and this valve is urged to its seat by a helical spring 54 housed in the valve 53. In order to avoid dash-pot action of 'the valve there are one or vmore perforations 55 through its walls. Formed in the bottom of the cylinderthe valve 55 and having one or more perforations'through its walls to prevent dashpot action. The valve 59 is urged to its seat a helical spring 61- contained in a hollow Iliig 62 screwed into'the casingfrom below.

hese valves actin 'the usual manner and are made in ractice of'ample size to admit the flow of tlie air streams without undue friction.' The perforations 52 in the'plug 50 act after the manner of a strainer to prevent any' obstructions reaching the valve -seat 51 or the valve seat 57 and thereby preventing the respective valves from properly seating therein. The outlet chamber 48 -isconnected by a conduit-63 with a reservoir tank 64, which I .may carry a suitable .separator 65 for taking out the dust and-dirt'from the air before reachin another'conduit 66 which may .conneetwit theintakechaniber47,so that under certain conditions of operation the same body 'of air -is -used l'over and over again.

vThe'reservoir (Mend-'separator 65 are-connectedbya conduit=67ltoacleaning head 68 provided with amanipulatinghandle 69, but

v Vas;--the-'construction of these several parts forms no vpart of theI present ,invention but are made the subject-matterof another application, these parts are neithershown nor described in'detail herein and are only shown the pump vand driving mechanism therefor Vmaybe-apparent. l f y .The end 'plate 4, together with the pumps .and-A the parts y'connected directly: therewith lis carried by a cylindrical casing 70 mounted upon a'suitable foot-or base .7.1.which maybe .east inrone'piecewith thecylinder70.. The end of the cylinder 70 op osite the plate-4 is closed by -a cap-plate -72' ormed at its center with a hub 73 in'which is :fitted aserew-plug 74 lockedy in place by a suitable lock-nut 75. Extending upward yfrom a point 'midway between the two cylinders is a post 76 having a tapered opening l7 7 in which is seated a (c 'in' order that Athe operation and -purposes of taper-cup 78 housing a sexies of balls 79 held 'in the cup b the conical end 8O of the shaft.

24. The ot er end of this shaft 2 4 has a 4conical end 81 engaging a series of antifriction balls 82 held bythe shaft in the interior of the Vhub 73 against the screw-plug 74. The cup 78 with the balls 79 and the hub 73 `with the screw-plug 74-andballs 82 constitute anti-friction bearings for the two ends of the shaft 24 and wear-may be readily taken up by means of the screw-plug 74. i

. Mounted upon the casing and directed radially inward are a suitable number of field coils 83 having pole ieces 84. Upon the shaft 24 is an extendedphub 85 engaging 66 the shaft near the ends only of the hub, and

.only one of which is shown.

be close tos this hub has cast ori it radial-arms or s okes 86y supportinga cylinder 87 upon whic are mounted the armature laminae 88 carrying the bars 89 of the usual squirrel cage type of armature, the showing in the drawing being 70 that of an alternating current motor of the squirrel cage type.

Mounted upon the shaft 24 at one end of the hub is a friction member in the form of a disk 90 which may have radial ribs 91 -75 formed thereon for purposes of strength. J ournaled on the disk 90 on the ribbed-side i thereof area number of bell-crank levers 92, Each lever has along arm terminatinin a weight 93, said 80 long4 arm extending etween two of the e spokes 86. The short arm 94 of the lever 92 is normally housed in a recess 95 in the clutch member 90 and is shaped to engage in a correspondingly laced projection 56 on the hub 85 85. The bel -crank lever 92 is constrained toward the hub 85 by a spring 97. Upon the hub 85 is mounted a spring arm 98 terminating at itsree end in a rounded lug 99.-' This ,spring arm is so placed that when the weight 93 restsupon the hub 85 the lug 99 enga es over theupperfedge .ofthe weight while t e corresponding lower edge is rounded, as shown at 100. Fast upon the shaft 24 is an- .otherdiskclu'tch'member 101 in operative 95 relation to the clutch member 90. 'lhe contiguous' faces of the two clutch members 90 and 101 are each formed with a series of annular ribs 102 so-arranged that the ribs on one clutch-member will intermesh with the' ribs on the otherA clutch member. These ribs are preferablyv of V-shape and may conform in'cross section to the cross section ofthe standard-screw'thread Now, let it lbe assumed that the motor is started and con- 105 tinuously picks-upspeed until it isv finally running at-full speed, which under load will chronism with the current. As the motor Increases in speed, the weighted ends ofthe vbell-crank levers tend to ily outward under centrifugal force. This is prevented, however,by the-engagement4 of the latch lugr 99 of the latclrspring 98 over the weight 90. Ultimately, however, the centrifugal force is ioo suflicient to cause the latch arm 98 to recede 1 15.

from engagement with the weight 93, and the latter will then immediately fly out against action of the spring 97 and by the engagement of the arm 94 of the lever 92 with the extension 96 of the hub 85`move the clutch 120 member 90 into engagement with the clutch member 101. The parts are so timed in operation that the. two members of the clutch are not brought into engagement until the motor has attained practically full load speed. Thus the -motor may be started-under no load and brought up to speed and then the load is placed upon the motor 'automatically. i By this means it is impossible for an'operatorunskilled in the management 130 .i bell-crank levers '02,. with .tlu\ \\'eiglits, into ol electric motors to stall the motor-.by loading the same at the start `-ouat- `some point where its torque is low. Nl'henthe motor is stopped the springsl `will bring the several engagement with the hub S5,A iuwhich position they willbe locked by the latchspring vvWhen vthe motor.v is clutched to the clutch lunember 101 the shaft 24 iscaused to rotate.,

and lthrough 'the wol-111723 and wormgear wheel 22the pump pistons are set in motion and working`r alternatelyl as4 a duplex pump. supply a steady stream ol` air to the reservoir 64. .The air in the reservoir passes to the eleaning head GS and is there directed foreibly'against the pa rtto be cleansed, loosening up the. dirt wlueh, together with th'e air, is removed from thelieziddo the deposit chamklZ0 ber.64 where the air is-clcansed from the matters it carries and ultimately returns' to the.:

the vacuun'i system. only may means'for these operations forms theasub'- ject-matter of another application and there- -forelare neither 'shownJnor desgribed herein.

Wlulefwe have described the 'use ot an alternating current-nnduetion 'motor 1n connecvltion with a pump, at-ontinuous current motor may be. usedxwhere'such currents are available, and-while a great variation ofload 1s perxmsslble with astralght current motor, sti

lit is advisableto fullyy load, or approxi.

matel fully loadf onlywhen they have at- '4(V`taine(v s eed, `for otherwise the rush of eurrent un( er full load at low-speed may be suflicient to burn out .the armaturc.- With the nd vacuum, -me'ans may be pro' s ii 1ecasesit may be, advan-f small size of motor. used in connection'withV the. domestic sizes of thc apparatus, a continnous current motor may be. safely started under no load wit-hout the use of starting resistances, and With -the'means which we have devised vfor ap lying the loadnautomatically only after .tlie motor has-attained speed vmakes it-'entirely feasible to place-such moto be present in the conduit. 67,-and the -air tors 'in the hands of persons unskilled in the. use. of elec-trie.. apparatus. Sup aosing, now, that. the voperator should elose .t .e air valve, which latter though-not shown is presumed shoul( accumulate in the reservoir 64. Unless there be provision to prevent such contingency this air pressure will risc to sue-h an extent as to overload the mot-or. With a continuous current motor of the shunt wound vtype this might mean a burned out armature, and with an alternating current induction motor it may mean a burned out field and other'injuries dueto the slowing down of the rotor of the motor.

pressure. accumulates on t ln order tmprevent injury to the motor when the air pressure in the reservoir accumulates beyond the normal pressure, there is provided a cylinder 103 which may be located below theinotor casing'70, and this cylinder isconnected to a'pipe 104 which may be connected to the pressure side of the pump or to the air reservoir. Vli'ithinl the cylinder is a piston rod ,105 surrounded by a helical'spring 10G engaging at one end ahead 107 ol"r the piston rod and at the other end abutting against a bushing 108 serewed into the open end 'of the cylinder and held in any nut 112 and washer. The piston rod 105 ectends beyond the bushing 10S and is there formed into ahead 113 embraemg the. lower endof a lever 11.4 and provided with radial slots 115 engaging the bushing eyes of a inV 116 passed laterally through the lever. 'lil upper end of thele-ver 1.14 is pivotally secured to the end plate-4 by a pivot screw or screw pin 117, andl adjacent to the pivoted end of the lever is formed into a head 118surrounding the shaft 24 and formed with diametrieally-oppositev rejections 119. Surroundingthe shaft 24 etween the head 118 and the corresponding end of the hub-85 is a cup 120 having ya ccntralr erforation 121 of suflicient s izc'to permit tlie 'passageof the shaft Without touching the same. This cup is engaged by the. V projections119 on one face and on the otherface is formed with an annulary .V groove 122 receiving a series of antifrietion balls 123 in engagement with the eorrespondingend faee. of the hub 85.

The pipe 104 is of small bore and at the point where vit leads into the cylinder 103 there is a valve 124 of comparatively large area, and opening into the cylinder on thatv side of the piston remote from the spring 106. The valve 124 is provided with a leak groove 125.v .Now,supposethat the s ring 106 is adjusted by means oft-he Ybusiing 108 to yield when .air at a pressure of, say one hun-A dred pounds per square inch, is brought to bear upon the reservoir side of the piston 111. f' As soon as the pumpl is started the air e pressure side of the piston 111 since it has free access thereto hy the comparatively large valve 124 sol that the air pressurein the cylinder 103 is at all times substantially that of the reservoir. The pump speed is SoadjuSted that at maximum speed it will pump air but slightly in exe-ess of the capacity of the largest cleaning head. Suppose that the spring-106 is adjusted to one hundred pounds, as before assumed, and the air used in the normal operationof the gde-vice is to be used at a pressure of ninety pounds and the apparatus 1s in opadjusted posit-ioirby a: lock-nut 109,' the y memes eration. New, the operator shuts off vthe air flowing to the clean-in head in order that the head may be remove to another part ofv the room or to some other location Yto there recommence operations. During this interval the pump 1s st1ll 1n operation and of course d re pounds is reac ed, when thespring 106 yields and the piston rod is projected from the bushing 108. Because of the friction .between the piston I1 1 1 and the Walls of the cylinder 103 more power is required to start the iston in motion than to kee i-t in motion. herefore when once started 1t will make a full traverse of the cylinder 103 against the action of the spring 106 until a point is reached where the maximum compression of the spring stops further movement of the piston. The parts` are so designed that this movement will carry the lever 114 on its ivot to an extent which will more than reieve the hub 85 from the pressure of the cup 120. I

The hub 85 is free to move longitudinally upon the shaft 24 and the pressure of the spring 106, when in its normal position, is sufficient to move the armature slightly to one side of the true magnetic osition, that is, the armature is moved slight yv toward the lclutch member 101 which is fast upon the shaft 24. Now, upon the compression of the spring 106 by the superior air pressure, the

ull of the iield upon the armature Will move 1t away from the clutch member 101, and the clutch member 90 will artici ate in this movement suiiiciently to ree it rom Contact with the other member 101. The armature continues to run freely under no load since it is uncoupled from the pumps and no more accumulation of air can occur in the reservoir. Su pose the operator again starts the cleaning ead into operation and the ressure in the reservoir will of course rop. The valve 124 at once seats and there re* mains, therefore there is an excess of air pressure on the power side of the piston 111.

. This excess of pressure however, gradually equalizes through the leak groove 125, which latter is of such dimensions, considering the size of the reservoir and the flow of air through the cleaning head, that the air in front of the piston 111 will reach a sufficiently low pressure, say about ninety-five pounds, so that the spring 104 will act about the time the pressure in the reservoir has reached ninety pounds. Now, the head 118 has been resting idly against the corres onding end of the hub 85, and even if loose y enaging the same the balls 123 cannot esca e rom the cup 120 because the walls of tie cup closely embrace the end of the sleeve, as seen in Fig. 1. As soon as the spring 106 acts, the cup 120 is pressed against the end of the hub and forces the same longitudinally upon the shaft until ultimately the member the dpressure runs u rapidly until one hun.

Q0 ofl the clutch ie breuglitinto engagement with the member 101. This action, however, is comparatively slow and, therefore, the clutch is brought gently into engagement and the pump 1s more or less gradually brought into action. Now, since the pump is capable of supplyingA air to the reservoir a little in excess o the demand, the pressure again gradually rises until it reaches about one hundred pounds and the pump is again cut out as before. Thispeculiar action of the valve 125 prevents excessive wear of the friction disks and the slow gain of the pump over the amount of air used ermits the pump to be cut in and out o y at stated time intervals, and while the action is gentle still it is positive.

While We have described the prime mover as an electric motor otherl types of motors may be usedand the means which we have described for cuttin the motors into and out of connection with t e pump ,either on start or when running, may be used With such ot er types of motors with such changes in lstructural details as may be necessary to of the motor the latter will be uncoupled from the ump to again come into action when the oad 1s a proximatel diminished. Also in the normal) action of t e device the arrangement is such that the plum slowly and progressively upon t e for air. slightly in excess of the demand and cumulative so that the motor is relieved from the load only when the accumulation of load has reached a certain maximum and is again cut in when the reduction of load has reached a predetermined minimum.

What is claimed is z- 1. In an air cleaning system, the combination of an air pump, a prime mover therefor, means for coupling the prime mover to the pump, and means for locking the coupling means against active movement unti the rime mover has attained approximately its full speed.

2. In an air cleaning system, the combination of an air pump, an electric motor for driving the same, means res onsive to centrifugal action for coupling t ie motor to the pump, and means opposing the action oi' centrifugal force for rendering the coupling means inactive until the motor has attained approximatel its full speed and then yielda e to centri ugal force.

gains emand ber ast upon the shaft, anot and the pum responsive to a predetermined centrifugal orce for coupling the prime 3. In an air cleaning system, the combination of an air pump, a prime mover for said pump, a shaft for transmitting motion'from the rime mover to the pum a clutch mem- .xber clutch member actuated bythe prime mover, a centrifugal member for moving the clutch member carried b the motor into engagement with the clutc member upon the shaft, and means for locking the centrifugal member against active motion until the motor has attained a predetermined speed.

4. In an air cleaning system, the combination of an air pump, a motor for driving the same, a friction clutch having one member 'in constant operative relation to the ump and the other member in operative re ation to the .motor, and means for moving the clutch members into operative relation com- 20 prismg centrifugal members carried by one vof the clutch members and acted upon by the motor, and the latch for each centrifugal member comprising a spring arm having a cam-acting enlargement locking the cen- 25 trif'ugal member againstV action until the centrifugal force reaches a predetermined maximum.

' 5. In an air cleaning system, the combination of an air pump, a prime mover for the same, a coupling between the prime mover mover and pump when the said prime mover has attained a predetermined speed, and means responsive to predetermined overload 6'. In, an air cleaning system, the combination of'an air pum a motor for driving the same, a friction c utch between the motor and pum centrifugal A clutch operating means, a ock for the centrifugal clutch operatin means responsive to a predetermined y centr' gal force, and means acting upon the clutch to uncouple the saine and responsive to a predetermmedair ressure above the working pressure supplie by the pump.

7. In an air cleaning system, the combina- Vtion of an air pum a motor for driving theetween the motor andV same, a clutch ump, means under the control of the motor or operating the clutch to couple the said motor to the pump, said motor having a normal tendencyv to operate the clutch to uncouple the motor from the pump without reducing the speed of the motor, and means for normally holding the motor againstits tendency to operate the clutch to the un* coupled position and to release the motor to cause it to move the clutch to the uncoupled position when the load exceeds a predetermined maximum, comprising a piston, a

spring actin thereon in one direction, con? nections to t e'pressure side ofthe pum for 65 supplying compressed air to that side o .the

-movable with the motor armature, a spring tending to maintain the clutch members 1n operative engagement and to shift the motor armature to one side of the magnetic plane of the field against the pull of the field, and means for overcoming the springwhen the air pressure exceeds a certain predetermined maximum to -permit the disengagement of the clutch members by Athe longitudinal movement of the motor armature under the pull of the field 9` In an air cleaning s stem, the combination of an air pum an e an armature mova le axially with relation to the field under the pull ofthe field, a clutch member yconnected to the pump, another clutch member carried by said armature and `movable with the same awa from the other clutch member under the pu l of the iield, an air cylinder, a piston in said cylinder, connections between the armature, a spring acting on said piston and tending to maintain the clutch members in engagement against the pull of the field, and

connections between the pressure side of the prump and that side of the piston remote om the spring whereby air pressure may act upon the piston in opposition to the s ring and inthe direction o the pull of the eld to unclutch the armature from the pump. 10. In an air cleaning system, the combination of an air pump, ane ectric motor having an armature movable axially with reference to. the field of the motor under the ull of the field, a clutch member connecte to the ump, another clutch member connected to tl'pie armature and movable therewith under the pull of the field away from the first clutch member, a lever engagin the end of 4the armature remote from the c utch, an air cylinder, a piston in said cylinder, a piston rod connected to said piston and to the free end of the lever, a spring acting on the piston to move the lever in a direction to maintain theclutch in engagement against the pull of the field, and air connections from the pressure side of the pump to that side of the piston remote from the s ring to move the piston in opposition to t e spring to uncouple the clutch when the air pressure exceeds a predetermined maximum..

- 11. In an air cleaning system, the combination of an air pump, an electric motor haviston and the motor ectric motor having tion to the motor fields, a shaft connected to the pump and carrying an armature, a clutch member fast upon the shaft, another clutch member rotatable with the armature but movable longitudinally with relation thereto, centrifugal operating means for the clutch member carried by the armature for moving f the said clutch member into engagement with the other clutch member, saidcentrifugal means being res ionsive only to a predetermined centrifugal force due to the rotation of the armature, a lever engaging the end of the armature remote from the clutch, an air cylinder, a piston therein, a piston rod connected to the piston and to the free end of the lever, a spring acting on the piston rod and tending to move the lever in the dire@ tion to bring the clutch members into engagement, and connections between the pressure side of the pump and the face of the piston remote from the s ring.

12. In an air c eaning system, the combination of an air pum a motor for driving the pump, centri uga ly operated means for coupling the motor to and uncoupling it from the pump, means responsive to a redeter# mined air pressure above the working pressure and acting on the coupling means independent of centrifugal action for uncoupling the motor from the pump, and means for causing the slug ish return of the last named means to norma position.

13. In an air cleaning system, the combination of an air pump, a niotorfor driving the same, a clutch between the motor and air pump, an air cylinder, a piston therein, connections between the piston and the clutch, a s ring acting on the piston to maintain the e utch members in engagement, air connections between the air pressure side of the pump and the side of the piston remote from the spring, and a valve in said air connection closing to the return of air from the cylinder toward the air ump, said valve being proe vided with a lea r passage for the gradual discharge of air from the cylinder toward the pressure side of the pump.

` 14. In an air cleaning system, the combination offan air pump, a motor for driving the same, a clutch between the motor and air pump, an air cylinder, a piston in said cylinder, connections between the piston and one of the clutch members, a spring tending to maintain the clutch members in engagement, means for adjusting the tension of the spring, air connections between the pressure side of the pump and that side of the piston remote from the spring, and a valve in said air connections closing to the return of air from the cylinder toward the pump, and provided with a leali passage from the piston side of the valve toward the pump side thereof.

l5. In an air cleaning system, the combination of an air pump, an electric motor for driving the same having its armature movable axially with reference to the iield of the motor, a shaft upon which the armature is mounted and which shaft is connected to the air pump, a friction clutch member secured to said shaft, another friction clutch member mounted upon the shaft but rotatable and movable longitudinally thereon, centrifugal members mounted on the clutch member, and engaging the armature when moved under the action of centrifugal force to cause the second-named clutch member to engage the first-named clutch member, means for preventing the centrifugal members from acting until the armature attains a predetermined speed, a lever acting on the end of the armature from the clutch, an air cylinder, a piston therein, a piston rod carrying said piston and connected to said lever, a spring acting on the piston to cause the lever to maintain the clutch members in engagement, air connections between the pressure side of the pump and that side of the piston remote from the spring, and a valve in said air connect-ien provided with a leak passage and closing to the return of the air from the cylinder toward the pump.

16. In an air cleaning system, the combination of an air pump, an electric motor for driving the pump, means normally active at a speed below the full working speed of the motor for coupling the pump to the motor, and restraining means for the iirst named means responsive to a higher speed than the said first named means for releasing the latter when the motor has reached approximately full working speed.

In testimony that we claim the foregoing as Our own, we have hereto affixed our signatures in the-presence of two witnesses.

WILLIABI (l. BLA'YO. JOHN HO'ULlCl-IAN. Witnesses for Mayo:

WM. Annals, J. H. BUCHANAN. Witnesses for Houlehan:

MARY B. BUCHANAN, A. M. Writ/ruina..

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