US2641330A - Vacuum cleaner - Google Patents

Description

June 9, 1953 G. E. LOFGREN E'TAL 2,641,330

VACUUM CLEANER Filed Jan. 25, 1950 ll Sheets-Sheet 1 mmvroxs.

GusmF EINAR LOFGREN ROBERT c. LAMPE JOHN r FERRARIS BY W 7 TTORNEX June 9, 1953 G. E. LOFGREN ET AL 1,3

' VACUUM CLEANER Filed Jan. 25, 1950 ll Sheets-Sheet 2 GUSTAF EIN LOFGREN ROBERT- C. L MPE JOHN T FERRARIS JNVHVTORS; A 12 June 9, 1953 G. E. LOFGREN EI'AL VACUUM CLEANER l1 SheetsSheet 5 Filed Jan. 25, 1950 INVENTORS. gUSYFlF EIAMR LOFGREN OBERT c. LAMPE JOHN T FERRARIS 'M 2 TTORNEY INVENTORSJ GUSTAF EINAR LOFGREN ROBERT c. LAMPE 11' Sheets-Sheet 5 JOHN T maze/1121s B gnaw?! G. E. LOFGREN ETAL VACUUM CLEANER June 9, 1953 Filed Jan. 25, 1950 June 9, 1953 G. E. LOFGREN ET AL 3 VACUUM CLEANER Filed Jan. 25, 1950 11 Sheets-Sheet 7 INVENTORS. GUSTAF EINAR LOFGREN 10 11% ROBERT c. LAMPE JOHN T FERRARIS June 9, 1 953 G. E. LOFGRENY ETAL 2,641,330

VACUUM CLEANER Filed Jan. 25, 1950 ll Sheets-Sheet 8 INVENTORS. GUST/IF EINAR LOFGREN ROBERT C. LAMPE JOHN T. FER/M1215 By 71.4.4; M

T TORNEY.

VACUUM CLEANER ll Sheets-Sheet 9 Filed Jan. 25, 1950 mm Tm M F R IRMMAH MTI N WWW Wm H w M 4 NH Q 2 -m 4/ /N/ m Q g r t H l June 9, 1953 G. E. LOFGREN ETAL 2,641,330

' I VACUUM CLEANER Filed Jan. 25. 1950 I1 Sheets-Sheet l0 :aoo

. INVENTORS. GUSTAF EINAR LOFGREN ROBERT c. LAMPE JOHN T FERRARIS BY T ORNEV.

June 9, 1953 G. E. 'LOFGREN ETAL VACUUM CLEANER ll Sheets-Sheet 11 Filed Jan. 25, 1950 INVENTORS. GUSTAF EINAR LOFGREN ROBERT c. LAMPE JOHN 77 FERRARJS BY 2 M TTORNEI/ Patented June 9, 1953 UNITED STATES PATENT OFFICE 2,641,330 VACUUM CLEANER Gustaf Einar Lofgren, Riversid Robert C. Lamps, Stamford, and John T. Ferraris, Cos

Cob, 001111., assignors to Electron (Loriaoration, 016 Greenwich, Conn, a corporation of Delaware Application January 25, 195.0, Serial ND. 140,394

22 Claims. 1

This invention relates to improvements in a vacuum or suction type cleaner having automatic controls. More particularly, it embraces an automatically conditioned tank type cleaner having self-contained control mechanisms for removing accumulated dirt in packaged form readied for immediate disposal. With this cleaner the dirt entrained in the'inccming air suction stream is collected in a porous disposable bag located within the cleaner and when the collected dirt effects a predetermined change in the operating efficiency of the cleaner, the latter automatically shuts itself off and disposes of the dirt-filled bag by ejecting the latter from the cleaner.

It is a major object of this invention to provide a new and improved vacuum cleaner having automatic means for disposing of dust and dirt by ejecting from the cleaner a self-sealing porous and disposable paper bag filled with dust and dirt separated from the suction air stream drawn through the cleaner.

It is a further and important object hereof to provide completely automatic means for efiecting the operation of a dust bag ejecting device upon the attainment of a predetermined condition or status of operation within the cleaner.

A still further object is to provide a vacuum cleaner which has a large dust collecting capacity and which operates at a substantially uniform efficiency.

A further object of this invention is to provide a device which avoids the inconveniences present in the conventional suction type of vacuum cleaning device using the customary cloth or paper dust bag which periodically necessitates indiscriminate removal or replacement in order to maintain a semblance of efficient operation, such bag removal steps being heretofore effected manually and with considerable difficulty and discomfiture on the part of the operator.

Still other and further objects willbe disclosed hereinbelow or will become evident to those skilled in the art after a carefiil study of the following description together with the appended drawings wherein: v

Figure 1 is a perspective View of the complete cleaner as seen from the air intake end, sans nozzle, conventional wand and hose;

Figure 2 is a perspective view of a portion of the cleaner and hose taken from a position simiejector plate pushed back and a conventional 2 cloth type bag in exploded view and with its cloth portion partly cut away, the bag being in position for insertion into the dust bag compartmerit of the cleaner housing;

Figured is a vertical sectional view taken on the line 1 -4 of Figs. 1 and '7';

Figure 5 is a horizontal sectional view taken on the line ii-=5 of Figs. 1 and '7;

Figure 6 is a partial horizontal sectional view taken on the line 6-=$ of Fig. 2, showing the cover opened and the scissors ejector mechanism fully distended;

Figure '7 is a front plan View of the cover of Fig. 1 in closed position;

1 Figure 8 is a vertical sectional view taken on the line 8-8 of Fig. 12, showing the cut-out switch, which cooperates with a projection on the non-disposable cloth dust bag of Fig. 3 for disconnecting the automatic controls from operation;

Figure 9 is a vertical sectional view taken on the line 9-8 of Fig. 7 showing the parallel linkage of the hose coupling assembly to the cover;

Figure '10 is'a sectional view taken on the line iii-it of Fig. '7, showing the manually operable button for releasing the front cover;

Figure '1-1 is a sectional view taken on the line [I -N of Fig. 7 showing the manually operable switch actuating button for energizing and deenergizing' the motor fan unit;

Figure 12 is a horizontal sectional view taken on the line 12-42 of Fig. '7 showing the linkage control for automatically releasing the dust bag ejector device;

Figure l3 is a wiring diagram including some of the pneumatic controls; and

Figure 14 is an exploded perspective View with portions cut away in section showing the eleo-' tro-pheuinatic control unit and details of its internal construction.

It is a feature of this invention that the functioning of the cleaner in itsdu'st disposal capacity sequenceof operations terminating in the ejection'oi the dust-filled bag is effected in a series the cleaner between the inside and the outside or the dust-collecting bag'. This results in a-contmuous and progressively increasing force being exerted upon a pressure differential measuring diaphragm, the opposite sides of which are subjected tothe di'iie'r'eht pressures built up on the 3 outside and inside of the dust bag, the chamber on one side of the diaphragm being connected to an opening communicating with the clean side of the dust bag, the space on the other side of the diaphragm being connected to an opening communicating with the dirty side of the dust bag. Then, upon the attainment of a predeterin the ejection of the dust-filled'bag from'the cleaner housing.

In a preferred embodiment, the differential pressure diaphragm actuates a switch which closes a circuit for energizing an electromagnetically actuated armature or solenoidal unit. The armature or plunger of the electromagnetic device in turn opens a valve for admitting suction from the motor fan unit to actuate a second diaphragm which operates through a series of linkages to release (1) a first ejector mechanism restraining latch and thereafter or in timed relation thereto (2) the cover of the cleaner housing. Then, the cover after a predetermined angular travel toward its fully opened position in turn breaks a circuit cutting off the power supply to the motor fan unit. Continued travel of the cover towards fully opened position subsequently releases a second and final ejector restraining latch for actually releasing the bag ejector mechanism for dust bag ejection, whereupon the dustfilled bag is expelled from the cleaner housing and deposited upon the floor. During these cover opening steps, the timely breaking of the motor fan circuit results in a progressively slowing down in motor fan speed and consequently the air suction stream also progressively decreases to avalue at which highly effective bag ejection is more readily attained.

Thus in accordance with this preferred embodiment of the invention, automatic dust bag ejection is effected by mechanical means, after being initiated by a tripping mechanism including a pressure differential measuring device which actuates a responsive triggering apparatus. The pressure differential measuring device is conditioned for operation by utilizing the air pressure difference built up within the cleaner casing by dust layers collected in the dust bag. This pressure difference is established between the inside and outside of the dust collecting bag and is communicated therefrom by appropriate conduit means throughout the dust collecting process.

Referring now more particularly to the drawings, vacuum cleaner housing [8, Fig. 1, is a hollow casing having a handle .I I. It is appropriately supported on a pair of runners l2. The suction or inlet portion of the casing It is provided with an air inlet nozzle and wand (not shown) together with a suitable flexible hose l3, Figs. 2, 3, and connecting coupling 14a fitted into a movable hose coupling assembly [5 mounted on cover l6. Cover I6, Fig. 6, hinged at I! to front body ring and biased to open position by spring l8, effects with casing If! an air tight seal formed by rubber ealing ring member l9, cardboard disc 3| of dust bag and sealing ring 22 positioned in the bag insertion opening of front body ring 2!], Fig. 5. Tubular member 21 of the hose coupling assembly l5 extends through the opening 32 cut in cardboard disc 3| well into the dust collecting receptacle 30, and is sealed against disc 3| by rubber sealing ring 19. Switch button Hia on cover l6 provides the on-and-off manual control for the cleaner unit.

A perforated sleeve 23 is aflixed at one end to front body ring 20 and is adapted for supporting dust bag 30 (of disposable paper or cloth construction). This entire unit (sleeve 23, body ring 28, etc.) is slidably fitted within the open end of cleaner housing It and is aifixed thereto by retaining screws. 24, Figs. 1, 2, 3, etc. In the embodiment shown, sleeve 23, reinforced by lateral stiffening plate 25 and base rods 26, is substantially rectangular in cross-section and is thus adapted to take a bag 36 of substantially similar but slightly smaller cross-section, Figs. 2, 3 and 4.

Two types of dust bag are illustrated, a disposable and a permanent one. Dust bag 30, Fig. 2, comprises a dust receptacle of paper or similarly air-pervious, dust-impervious, material 33 afiixed at its mouth to the rear surface of a hard paper or cardboard disc 3!, the latter being clamped between rubber sealing ring l9 of hose coupling assembly l5 and the open end of front body ring 29 with the aid of sealing ring'22. Cardboard disc 3! has a central opening 32 through which tubular member 2| is inserted in order to introduce the air and entrained dust directly into the interior of dust bag 30. The permanent cloth bag of Fig. 3 is used when the automatic controls and dust bag ejection are not desired (see detailed description below).

The entire inner surface of perforated sleeve member or dust bag receiving compartment 23 is provided with apertures 21, Figs. 3, 4, and 6, in order to permit suction air current to pass freely therethrough and into chamber 40, the air also passing to compartment 59 containing the ejector scissors 53 and its associated expulsion spring assembly 5!. Thereafter the suction air current passes through motor fan compartment lfi which contains mounted therein fan (I and motor 72. The fan is provided with an air inlet l3 through which the air passes to the housing of motor 72 and out through louver open- The scissors ejector mechanism 5!, 53, Figs. 4, 5 and 6, for operating the bag ejector plate 52 is in the form of a collapsible spring loaded lazy tongs 53 which can be collapsed into fully flexed (loaded) condition, Fig. 5, by pushing back ejector plate 52 hingedly attached by pins to the front pair of scissors blades 52a. Mutually intermeshing gear teeth 54 cut in coacting portions of the front pair of scissors blades keep plate 52 oriented correctly throughout the extent of its travel. U-shaped frame member 55 afiixed to the rear end of perforated sleeve 23 supports the ends of the rear pair of scissors blades 53c by holding the latter between a pair of sleeves 56, all being bearinged on pin 5?. The scissors mechanism is biased to fully distended position 3 Beans-bell crank-6'3 Fig. 12,- forms: another compositabell' crank" biased to: latching positionbi spring-59.

The above'latchesfor restraining the ejector mechanismv are operated through appropriate linkages; Thus rearlatch 63 is moved toreleasin-g position by automatictriggering initiated by pneumatically actuated means: (described below) and transmitted through link- 8 I, and a bell crank formedof lever arm 83, pin 85 and lever arm .37, Fig. 12, while lever arm 83 is actuated in turn by bell crank 89, Figs. 4, 9 and 12, fulcrumed at 9i: and linked directly to thepneumatically operated triggering device 250.

Front latch 62- is'moved' to releasing position by-thefinal opening stages of. the released front cover- IB through link 82 and a bellcrankform oflever arm 84, pin 86', and lever arm 88, while the latter is actuated byslide or draw bar 92 which is pulled outwardlyby a cam" 94 on the parallel linkage I I501" the hose coupling assembly I5 With' this particular latching device for restraining the scissors ejector' mechanism 5|, plate 521s held in loaded-position until cover I6 is practically fully opened. Cover: I6 is normally held closed by latch" I00, Figs. 2, 3 and 10, fulcrumedat IUI and biased to retain cover $5 in closed position by tension spring I02.

Thecovermay be opened for inspection of the bag-and its contents, however, without neces sarily ejecting the dust bag, by pressing release button IE?) on cover IB- downwards and (Fig. 10) causing plunger I05 held'throughelongated slot I06 by retaining screw I01 and biased upwards by spring I08 to contact latch I00. Pressing button IBb forces plunger I05 downwards against latch Ill'fl thusreleasing cover I6. Then, even with front latch 62 released by the-opening of cover IE to. its fullextent, rear latch 63 restrains scissors ejector 53 from discharging the dust bag. Latch 63-thus serves as an auxiliary safety latch preventing the dust bag in either full'or empty condition from being ejected upon manually opening cover IE. on the other hand, with cover I3 closed, latch '52 similarly serves as an auxiliary safety latch preventing the compression and jamming of bag 30 within sleeve member 23 even though latch 63 may have been released by the triggering action of. pneumatically operated device 250.

It is to be noted that pneumatically operated device 250 in addition totriggering rear ejector latch 63 also releases cover restraininglatch I00 by" actuating lever I3I, Figs. 10', 12, 13, ful-- crumed at I32.

The parallel linkage of the hose coupling assembly I5 to the cover I6 is most clearly-shown in Fig. 9, where bell crank H5 fulcrumed at IIB to frontring 20 and at IIT to hose coupling assembly I5'forms one link of the complete parallel linkage while cover II; (itself), fulcrumed at I'I to. front ring 20 and at H8 to hose couplingassembly I5, forms the. other link.

Button. 16a on cover 'I 5' operates the switch button. III), Fig; 11, of a conventional on-and-ofi toggle type snap switch 3H1 through plunger III slidably held in a groove H2 by retaining screw H3 and biased upwards by spring IM. Plunger III actuates bell crank I23 fulcrumed at I2I through one arm thereof, the other I22 of which operates switch button III]. However, although button IBa may be'usedwto start and stop the motonfan unit while the' cover I6 is closed, the opening Fig. 9 of cover" I3" causes 2; lug 95 of parallel: linkages I I5? to" release. one leg: of: a: U

shaped" switch rocker arm. 96', Figs.=11, 12 andz13'; fulcrumed'at'fll and biased for clockwise rotation by spring 98'. Thusiwhen the cover isuopened: theother leg of switch arm actuates'pin 99 of.

the-on-and-ofl switch 3! to its off position, thereby stopping'the motor fan unit andother wise deenergizing: the entire cleaner unit.

The electricaland pneumatic control units are closely and operatively interrelated. The pneumatic system includes a pressure difierential measuring control device 200, Fig. 14, comprising an -upper-casing-2Ill and a lower casing 202 separated by a diaphragm 203 pneumatically sealed. therebetween. The space in the upper casing abovewdiaphragm 203 is connected by communieating conduit 2| I), Figs. 4 and 14 to opening '21 5; Fig. 5, on the dirty or dust collecting side of the dust bag. The space in the lower casing below diaphragm-203 is connected bycommunicating conduit 22D, T-shaped coupling 22I and common conduit 225to 'opening' 233, Figs. 4, 5, 6 and 12, on the clean side of the dust bag. The remaining connection from T-shaped coupling 22! communicates by means of conduit 23I with one side of valve 243' comprising valve stem 2 H and valve face-242' biased'to closed position by spring 243.. When valve 24:; is open it communicates high suction to the interlor'of pneumatically" operating triggering device 250; comprising a lowerv casing 25I pneumatically sealed by diaphragm 252 biased to distended or upward position by spring 253 and capable of actuating tripping mechanism through link member 254.

The electrical system for energizing the motor. fan unit andthe electrical controls'are clearly shown in diagrammatic form in Fig. 13. Vacuum cleaner electrical cord 303 conveys current from the house lines at volts to terminal strips 301 located within the cleaner housing and from which one line 302 goes to motor 12, while the other line goes to motor I2 through a circuit including line 355, on-and-of'f switch 315, line 3H and line 3 I 3. The circuit for energizing the elec-- tricalcontrols comprises line 320, cut-out switch 32 I, line 322, electromagnet 325, line 325, pneue matically operated switch 321 of pressure difierentialpneumatic control unit 200, and line 328 to the house circuit'through the cleaner cord. 330. Cut-out switch 32I, Figs. 8 and 13, is normally closed; bell crank IB'I' fulcrumed at leebeing biased to switch closing position by spring I99 except when a special cloth bag unit Fig. 3 (described'below) is used for dust collection. The switch 321 of pressure'differential pneumatic control'unit 200'comprises a biasing spring 339, 14, which serves as a conducting element and for maintaining switch 321 normally open, together with contacts 33I and 332.

In detail and particularly with respect to the operation of the pneumatic and electrical controls, and referring especially to Figs. 13 and 14 where details of structure are clearly illustrated, the force exerted on the pressure differential diaphragm 2133- progressively increases with continued dust collection, until it attains sufficient value to actuate switching means 32'! and complete a circuit by closing contacts 3 3i and 332m pressure differential controlunit 21W Figs. 4, 13; li and thereby energize electromagnet 325. The armature 350 of energized electromagnet 325 ful-. crummed at 35! and biased by spring 352 to holdv valve 253 more securely closed, thenmovesdownwardly and' opens valve 240 allowing high;suc:.-

ti'cnto be-bonnnunicated: to: and: operates.

phragm 252' which in turn through 'a series of linkages 254, 255, bell crank 89, etc., releases rear latch 53, Figs. 4, 6, 9 and 12, holding ejection plate 52. Also by actuating lever l3l, Figs. 12 and 13, diaphragm 252 by way of linkage 254 trips cover releasing latch I00, Figs. 4, 10 and 12, which latch holds cover l6 closed against spring tension. The release of cover [6 first breaks a circuit at the contact points of switch 3N through release of rocker arm 96 which is biased by spring 98 to throw switch 3 l U to 01f position, Figs. 9, 11, thereby deenergizing the motor fan unit. Thereafter the front cover continues to open and after opening substantially 90, mechanical trigger mechanism comprising cam 94 of parallel linkage l l 5 trips draw bar 92 releasing front latch 62 and hence the bag ejector mechanism 5| through a previously traced series of linkages, allowing the bag ejector plate 52, Figs. 4, 6 to push the bag forward and throw the bag and its contained dirt out of the cleaner casing.

The ejector plate 52 moves forward and outward when released until stops 50, Fig. 6, abut in the forepart of the scissors mechanism 53. The momentum of the moving dust-filled bag causes it to continue onward in its own trajectory out of the cleaner casing after which it comes to rest on the floor.

The cloth bag shown in Fig. 3 is used when it is not desired to effect dust bag ejection. With this bag, a projection I15 on the lower edge of the metal ring 176 to which clot-h dust bag I1! is attached pushes against the upper end of bell crank I91, Fig. 8, interrupting the electrical circuit of the control mechanism Fig. 13. then decides himself when to empty this cloth bag. To empty this cloth bag, inner cover H8 is removed by releasing two latches I19, whereupon the dust and dirt is shaken out manually.

Various other details of construction are shown in the accompanying drawings. Thus, the base plate ltil, Fig. 4, sealing oft the housing at the bottom of the dust bag and screen compartment 48 together with depending partitions l8! and E82 forms a bag storage chamber I85 (see also Fig. l), which may also be used for storage of a cord reel. Leaf springs I90 keep the inner folded end of paper dust bag 30 from jamming under plate 52 and between the bottom edge of plate 52 and the floor of the dust bag compartment 23. The angularly bent portion 52a of plate 52 serves to keep the bag from crimping and jamming during ejection.

It is to be understood that the invention is not to be limited to the various structural features illustrated and described but that the same may be variously otherwise embodied within the scope of the appended claims.

What we claim is:

1. In a vacuum cleaner, the combination comprising a casing formed with an opening, a dust bag removable from said casing through said opening, a cover member for said opening, an inlet conduit having its inner end communicating with the interior of said bag, means for inducing flow of air through said conduit into said bag, and a control member movable to open said cover in response to variations in the difierential of the air pressure existing in said conduit at a point spaced outwardly from its inner end and the air pressure existing in said casing between said bag and said flow producing means.

2. In a vacuum cleaner, the combination comprising a casing formed with an opening, a dust bag removable .from said casing through said The operator opening, a cover member for said opening, an inlet conduit having its inner end communicat- -ing with the interior of said bag, means for inducing flow of air through said conduit into said bag, a diaphragm subject on one side to the air pressure existing in said conduit at a point spaced outwardly from its inner end and on the other side to the air pressure existing in said casing between said bag and said flow producing means, and means responsive to movement of said diaphragm for opening said cover.

3. In a vacuum cleaner, the combination comprising a casing having compartments and an opening, a movable cover for said opening, releasable means for holding said cover in closed position, means for producing a flow of air through said casing, a dust bag in said casing in the path of said air flow for separating entrained dirt from said air, means responsive to a predetermined change in the pressure characteristics between predetermined compartments within said casing for operating said cover releasing means, manually operative means for operating said cover releasing means, and means for ejecting said dust bag actuated only by opening of said cover in response to said change in pressure.

4. In a vacuum cleaner, the combination comprising a casing having an opening, a movable cover for said opening, releasable means for holding said cover in closed position, means for producing a flow of air through said casing, a dust bag in said casing in the path of said air flow for separating entrained dirt from said air, means responsive to the establishment of a predetermined pressure difference between the inside and outside of said dust bag for operating said cover releasing means, releasable means for ejecting said dust bag, means responsive substantially simultaneously with the opening of said cover for placing said releasable bag ejecting means in condition for operation, additional means responsive to the opening of said cover for deenergizing the air flow producing means, and further means responsive to the complete opening of said cover for ei fecting the operation of said releasable bag ejecting means whereby the bag ejecting means is capable of more effective ejection of the dust bag.

5. In a vacuum cleaner, the combination comprising a casing having an opening, a movable cover for said opening, releasable means for holding said cover in closed position, means for producing a flow of air through said casing, a dust bag in said casing in the path of said air fiow for separating entrained dirt from said air, air pressure means for operating said cover releasing means, valve means for controlling said air pressure means, electromagnetic means for actuating said valve means, differential air pressure responsive means operative upon the attainment of a predetermined pressure difierence between the inside and outside of the dust bag for energizing said electromagnetic means, and additional means responsive to the opening of said cover for ejecting said dust bag.

6. In a vacuum cleaner, the combination comprising a casing having an opening, a movable cover for said opening, releasable means for holding said cover in closed position, means for producing a flow of air through said casing, a dust bag in said casing in the path of said air flow for separating entrained dirt from said air, means responsive to a predetermined change in the pressure characteristics within and without said dust bag for moving said dust bag to a predetermined and additional means responsive to the opening of said cover for ejecting said dust bag.

7. In avacuum cleaner, the combination comprising a casing having an opening, a movable cover for said opening, releasable means forholding said cover in closed position, means for producing a flow of air through said casing, a dust bag in said casing in the path of said air flow for separating entrained dirt from said air, air pressure means for operating said cover releasing means, valve means for controlling said air pressure means, electromagnetic means for actuating said valve means, differential :air pressure responsive means operative upon the attainment of apredetermined pressure difference between the inside and outside of the dust bag for energizing said electromagnetic means,releasable means for ejecting said dust bag, means responsive substantially simultaneously with the opening of said cover for placing said releasable bag ejecting means in condition .for operation, additional means responsive to the opening of said cover for deenergizing the air flow producing means, and further means responsive to the complete opening of said cover for effecting the operation of said releasable bag ejecting means.

8. In a vacuum cleaner, the combination comprising a casing having an opening, a movable cover for said opening, releasable means for holding said cover in closed position, means for producing a flow of air through said casing, a dust bag in said casing in the path of said air flow for separating entrained dirt from said air, releasable means for ejecting said dust bag, pneumatically operable diaphragm means for operating said cover releasing means and for placing said ejecting means in condition for operation, valve means for controlling said pneumatically operable means, electromagnetic means for actuating said valve means, differential air pressure responsive means operative upon the attainment of a predetermined pressure difierence between the inside and outside of the dust bag for energizing said electromagnetic means, additional means responsive to the opening of said cover for deenergizing the air flow producing means, and further means responsive to the complete opening'of said cover for effecting the operation of said releasable bag ejecting means.

9. In a vacuum cleaner, the combination comprising a casing having an opening, a movable cover for opening-releasable means for hold- .further means responsive to the completc'open- 10 ingyof. said cover, for effectingthe. release of =said restraining means.

10. Inavacuumcleaner, the combination comprising a casing having an opening, amovable cover for saidopening, releasable means .forholding said cover in closed position, means-for producing a How of air through said casing, .a ,dust bag in said casing in the path of saidiairiflow for separating entrained dirt irom,-said, air, releasablemeans for ejecting said dust bag, mechanically operable triggering, means operable for placing the ejecting means in condition .for operation, pneumatically operable diaphragmv means for operating said triggering means andsaid cover releasing means, valve :means .for controlling said pneumatically operable means, electromagnetic means for actuating said valve means, .difierential air pressure responsive means operative upon the attainment of a'predetermined pressure difference between the insideandoutsideof the ,dust bag for energizing said electromagnetic,v means, means responsive to opening of said. cover for releasing the meansior ejecting said dustflbag, Whenever said ejecting means has beenwplaced in condition for operation, a cut-out means for rendering said electromagnetic means inoperative, and means on the dust bag foractua'ting said cut-out means to render the automatic ejecting means inoperable.

11. In a vacuum cleanerfla casing having,. an opening, a movable 'cover for said opening, means for producing flow of-air through saidcasinan dust separating bag in saidicasing .inthepaithof air now therethrough, spring biased meansjior ejecting said bag from said casingthroughsaid opening, first latching meansfor retaining said ejecting means in fully .retractedposition, means responsive to a predetermined pressure .Idrop through said bag for releasing said first latching means and for opening said cover, secondlatching means for-arresting movement of said ejecting' means after the, latter has been. releasedby said first latching means, and meansresponsive to opening of said cover forv releasing said second latching means.

12. In a vacuum cleaner, a casing having-an opening, a movable cover forsaid opening, electrically driven means for producing fiow ofuair through said casing, means for supplying current to said electrically driven. means; a dustseparating bag in said casing in .the pathof air flow therethrough, spring biased means .for ejecting said bag fromsaid casing through saidopening, first latching means for retaining said ejecting means in fully retracted position, means responsive to a predetermined pressure .drop through said bag for-opening said cover-and for releasing said first latching means, second latching means for arresting movement of said ejecting-:means after the latter has .been released by saidifirst latching means, and means responsiveto opening of said'cover for interrupting said'supply of current and for releasing saidtsecondailatching means.

13. In a vacuum cleaner,acasingAhaVingEan opening, a movable cover for saidopeninggmeans for producing flow of air through said. casing,,-a dust separating member in said casing in theipath of .air' flow therethrough, pneumaticmeans for opening said cover, valve means for-controllin said pneumatic means, electromagnetic means for actuating said valve means, andnmeans'responsive to difference in pressure atoppositesides ofv said dust-separating member for operating said electromagnetic means.

14. In a vacuum cleaner, a casing having an opening, means for producing flow of air through said casing, a dust separating container in said casing in the path of air flow therethrough, spring biased means for ejecting said container from said casing through said opening, pneumatically operated means for releasing said ejecting means,

valve means for controlling said pneumatically operated means, electromagnetic means for actuating said valve means, and means responsive to difference in pressure at opposite sides of said dust separating container for operating said electromagnetic means.

15. In a vacuum cleaner, a casing having an opening, a movable cover for said opening, means for producing flow of air through said casing, a dust separating container in said casing in the path of air flow therethrough, spring biased means for ejecting said container through said opening, pneumatically operated means for opening said cover and releasing said ejecting means, valve means for controlling said pneumatically operated means, electromagnetic means for actuating said valve means, and difierential pressure responsive means subjected to the pressures at opposite sides of said dust separating container for operating said electromagnetic means.

16. In a vacuum cleaner, a casing having an opening, a movable cover for said opening, fan means for creating a pressure in said casing different from atmospheric pressure to thereby produce flow of air through the casing, a dust separating member in said casing in the path of air flow therethrough, pneumatically operable means for opening said cover, valve means for controlling the application to said pneumatic means of the pressure difierence created by said fan, electromagnetic means for actuating said valve means, and means responsive to difference in pressure at opposite sides of said dust separating member due to the pressure drop of the air flowing therethrough for operating said electroma netic means.

17. In a vacuum cleaner, a casing having an opening, a movable cover for said opening, fan means for creating suction in said casing to thereby produce flow of air therethrough, a dust separating member in said casing in the path of air flow therethrough, a power diaphragm for opening said cover, valve means for controlling the application of said suction to said diaphragm, electromagnetic means for actuating said valve means, an electric switch for energizing said electromagnetic means, and a control diaphragm responsive to difference in pressure at opposite sides of said dust separating member due to the pres sure drop of air flowing therethrough for operating said switch.

18. In a vacuum clearer, a casing having an opening, a movable cover for said opening, means for producing flow of air through said casing, a dust separating bag in said casing in the path of air flow therethrough, spring biased means for ejecting said bag from said casing through said opening, first latching means for retaining said ejecting'means in fully retracted position, pneumatic means for opening said cover and for releasing said first latching means, valve means for controlling said pneumatic means, electromagnetic means for actuating said valve means, means responsive to difierence in pressure at opposite sides of said dust bag for operating said electromagnetic means, second latching means for arresting movement of said ejecting means after the latter has been released by said. first latching means, and means responsive to opening of said cover for releasing said second latching means. I 19. In a vacuum cleaner, a casing having a opening, a movable cover for said opening, electricall driven means for producing flow of air through said casing, means for supplying current to said electrically driven means, a dust separating bag in said casing in the path of air flow therethrough, spring biased means for ejecting said bag from said casing through said opening, first latching means for retaining said ejecting means in fully retracted position, pneumatic means for opening said cover and for releasing said first latching means, valve means for controlling said pneumatic means, electromagnetic means for actuating said valve means, means responsive to difierence in pressure at opposite sides of said dust bag for operating said electromagnetic means, second latching means for arresting 1 movement of said ejecting means after the latter has been released by said first latching means, means responsive to partial opening of said cover for interrupting said supply of current, and means responsive to substantially complete opening of said cover for releasing said second latching means.

20. In a vacuum cleaner, a casing having an opening, means for producing flow of air through said casing, a dust separating container in said casing in the path of air flow therethrough, spring biased means for ejecting said container from said casing through said opening, means responsive to an increase in pressure drop through said container for releasing said ejecting means, and means associated with said dust separating container for rendering the pressure responsive means inoperative.

21. In a vacuum cleaner, a casing enclosing a dust receptacle compartment with an opening to the exterior, a dust separating member insertable into said compartment through said opening, means for producing a flow of air through said member, a movable cover for said opening, pneumatically operated means for controlling the opening of said cover, valve means for controlling said pneumatic means, and means responsive to difference in pressure at opposite sides of said dust separating member for controlling said valve means.

22. In a vacuum cleaner, a casing enclosing a dust receptacle compartment with an opening to the exterior, means for producing a flow'of air through said compartment, a dust receptacle in said compartment in the path of air flow, spring biased means for outwardly moving said dust receptacle, pneumatically operated means for'releasing said spring biased means, valve means for controlling said pneumatic means, and means responsive to difference of pressure at opposite sides of said dust receptacle for operating said valve means.

GUSTAF EINAR LOFGREN. ROBERT C. LAMPE. JOHN '1". FERRARIS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,192,224 Forsberg Mar. 5, 1940 2,320,368 Leather June 1, 1943 2,325,188 Lofgren July 27, 1943 2,498,102 White Feb. 21, 1 950 2,580,644 Lofgren Jan. 1, 1952

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