US2714425A - Automatic vacuum cleaner - Google Patents

Description

Aug. 2, 1955 A. P. cAWL 2,714,425

AUTOMATIC VACUUM CLEANER Filed April 21, 1954 4 Sheets-Sheet l mmHmIFnmu uni INVENTOR 2, 1955 A. P. CAWL AUTOMATIC VACUUM CLEANER 4 Sheets-Sheet 2 Filed April 21, 1954 INVENTOR I a-ATTORNEY Aug. 2, 1955 A. P. CAWL 2,714,425

AUTOMATIC VACUUM CLEANER Filed April 21, 1954 4 Sheets-Sheet 3 INVENTOR Aug. 2, 1955 A. P. CAWL AUTOMATIC VACUUM CLEANER 4 Sheets-Sheet 4 Filed April 21, 1954 United ttes Patent .0

2,714,425 AUTOMATIC VACUUM CLEANER Allen P. Cawl, Stamford, Conn assignor to Electrolux Corporation, Old Greenwich, Conn., a corporation of Delaware Application April 21, 1954, Serial No. 424,547 3 Claims. (Cl. 183-37) My invention relates to vacuum cleaners and more particularly to vacuum cleaners of the automatic type wherein the operation of the cleaner is controlled in accordance with variations in air pressure occurring within the cleaner during use.

A preferred arrangement involves a pressure differential diaphragm or the like which is responsive to the attainment of a predetermined pressure drop of the air passing through the dust bag or other dust separating member for actuating a valve controlling the application of pressure or vacuum to a pneumatically actuated element such as a power diaphragm. The resulting actuation of the power diaphragm may cause merely the operation of a visible or audible signal, or it may include stopping the motor of the cleaner, opening the front cover and ejecting the dust container, or any one or more of these operations.

However, the value of the pressure drop at which it is desirable to have the control responsive may vary under different conditions. For example, if the dirt being picked up is relatively fine, it will quickly clog the pores of the dust bag with the result that a predetermined pressure drop of the air passing therethrough will result from a comparatively small quantity of this dirt. Such an increase in the pressure drop through the bag results in a decrease in the suction available at the nozzle and it is for this reason that it is desirable to stop the operation of the cleaner, or at least give warning to the operator, when the nozzle suction has reached such a low value that continued operation would be inefiicient in that the nozzle would not pick up sufiicient dirt. However, if the dirt being picked up is of the aforesaid fine character, less suction at the nozzle is required to remove it and therefore a greater pressure drop through the bag is permissible before the cleaning becomes inefficient.

Also, variations in the voltage of the electric current supplied to the motor of the cleaner changes the speed of the motor and of the fan driven thereby, and this results in changes in the suction produced by the fan which in turn varies the pressure drop through the dust bag without correspondingly altering the suction at the nozzle. Thus, an increase in voltage above normal increases the pressure drop through the bag but also increases the suction at the nozzle, whereas an increase in pressure drop due to a greater accumulation of dirt would decrease the nozzle suction. Hence, under conditions of high voltage a greater pressure drop is permissible as satisfactory cleaning eificiency will still be maintained.

Consequently, the prime object of my invention is to provide a control which may be readily adjusted from the exterior of the cleaner so as to vary the pressure drop through the dust bag at which the control will operate.

In accordance with my present invention, the movement of the pressure differential diaphragm causes it to contact the stem of a spring loaded valve controlling the operation of the power diaphragm so as to lift the valve from its seat. In order to obtain the desired variation in the value of the pressure differential necessary to open ment of the latter is desired result is obtained 2,714,425 Patented Aug. 2, 1955 =1 the valve, the entire valve assembly is adjustable towards and away from the diaphragm. Thus, if the valve assembly is positioned closer to the diaphragm, less displacenecessary to open the valve than if the valve assembly were positioned further from the diaphragm. Inasmuch as increased displacement of the diaphragm requires increased differential pressure, the and without requiring the use of adjustable valve openings, variable spring loadings or the like.

Further objects and advantages of my invention will be apparent from the following description when considered in connection with the accompanying drawings which form a part of the specification and of which:

Fig. 1 is a front view of a vacuum cleaner embodying the present invention;

Fig. 2 is a view, chiefly in cross-section, taken on the line 2-2 of Fig. 1;

Fig. 3 is a cross-sectional view on an enlarged scale taken on the line 33 of Fig. 4;

Fig. 4 is a top view of a control unit and front cover of the vacuum cleaner shown in Fig. 1;

Fig. 5 is a cross-sectional View taken on the line 5-5 of Fig. 3; and

Fig. 6 is a bottom view of the portion of the apparatus shown in Fig. 5.

Referring to the drawings, and more: particularly to Fig. 2, reference character 10 designates an airtight elongated body mounted on a pair of runners 12 which movably support the body in a substantially horizontal position on a surface, such as a floor. Disposed in the righthand portion of the body, as viewed in Fig. 2, is a motorfan unit comprising a fan 14 driven by an electric motor 16, the motor-fan unit being mounted within the body by means of an airtight partition or bulkhead 18. The fan is provided with an inlet opening which communicates with the space within the body to the left of the bulkhead. Within this space there is disposed an inner body 22 formed with a large number of apertures 24 so as to provide substantially unobstructed communication between the interior of the inner body and the inlet 20. The left end of the inner body is open and is secured to a ring 26 which in turn is secured in the open end of the outer body 10.

Secured underneath the body it adjacent to the left end thereof, as viewed in Fig. 2 is a hollow member 28 enclosing a control chamber 30. Extending forwardly from the front wall of member 28 is a pair of projections 32 to which is hinged a cover 34 by means of a pin 36. A coil spring 38 surrounds this pin and urges the cover to the open position shown in Fig. 4. As seen in Fig. 4, the left-hand part of the cover, which is the upper part when the cover is closed, is formed with a central cutout portion 40 within which is pivotally mounted a hose connector member 42 by means of pins 44. A link 48 is pivotally connected to the hose connector and to one of the projections 32, this link together with. the cover 34 constituting a parallel motion linkage for causing the hose connector 42 to move parallel to itself as the cover is opened and closed.

The hose connector is formed with an opening 50 extending therethrough, the outer end of which is formed as a portion of a separable coupling whereby a suction hose may be detachably connected thereto. The inner end of the opening communicates with an inlet conduit 52 which is surrounded by a flexible gasket 54.

Removably disposed within the inner body 22 is a dust separating member 56 made of porous material, such as paper, which is secured at one end to a stifr cardboard disc 58. This disc is formed with a centrally located aperture adapted to receive the inlet conduit 52 when the cover is in the closed position shown in Fig. 2, the gasket 54 bearedges thereof in posithe ring 26, thus closspring is disposed between the diaphragm and the bottom wall of the lower part 66 of the casing. This bottom wall is formed with a cylindrical .part 72 having a smooth cylindrical bore 73 of substantial length. The outer surface of cylindrical part 72 is provided with a screw thread 74.

Movably positioned within the bore 73 is a valve .assembly comprising a valve housing 76, a valve member 78 and ailoading spring '80. The housing 76 is formed with aseat 82 and the valve member 78 carries a packing ring 84 which provides an airtight seal against seat 82 when :the valve is closed. The loading spring 30 abuts against the bottom wall of the valve housing, which is disposed a fixed distance from the seat 82. Valve member 78 is formed with a stem 92 which extends upwardly towards the diaphragm 68 so as to be contacted by the diaphragm when the latter is moved downwardly against the force of its spring 70.

A pair of spaced sealing rings 86 is disposed between the valve housing and the bore 73 so as to prevent the leakage of air. An aperture 67 extends through the side wall of the valve housing between the sealing rings. The valve housing is provided with a skirt portion 88 formed with .an internal screw thread 90 which is adapted to engage the thread 74 on the outer surface of part 72. The

.outer surface of skirt 88 is preferably knurled or fluted so .as to constitute a manually turnable-knob which extends .outwardly through an opening 91 in the bottom of mem- .ber 28. Cooperating stops 93 and 95 are formed on --member 28 and skirt 88, respectively, which limit the. ro-

tation of the valve housing to a little less than a complete turn, thus preventing complete unscrewing of the valve housing from the part 72. As is shown in Fig. 6, the .knob 88 may be provided with a pointer 97 which cooperates with calibrations 99 on the bottom of member 28 to indicate the positionof the knob and valve housing.

A flexible conduit 94 communicates with the space withincap 64.above diaphragm 63 and leads to the front cover 34 where it connects with the opening 50 in the .hose con- .-nector member 42. Thus, the pressure existing within the opening 50 is communicated to the upper surface of the diaphragm 68.

A conduit 96 is connected to the space within the part .66 of casing 62 below the diaphragm 68 and leads to an opening 98 formed in an enlarged circular portion 100 of a .member 101 which, as is shown in Fig. 4, extends across the upper part of hollow member 28. A'gasket 102 is carried by circular portion 100 and surrounds theopening '98 and makes sealing contact with the lower surface of body 10 around an opening 104 therein. Consequently, the pressure existing within the body 10 is communicated to the lower surface of diaphragm 63.

A portion of member 28 is formed as a power diaphragm chamber 106 over which is disposed a relatively large power diaphragm 105. A conduit 110 extends from diaphragm chamber 106 and communicates with the bore 73 at a point between the two sealing rings 86.

Diaphragm 108 carries a stem 112 which extends through a slot 114 formed in a plate 116 which is secured to a rod 118 which is pivotally mounted in a side wall of member 28 and in a projection 119 depending from member 101. The upper end of stem 112 is provided with an enlarged head 120 so that downward movement of the stem causes the rod 113 to turn about its axis.

A front cover latch 122 is pivotally mounted at 124, as is shown in Fig. 4, and the right-hand end of this latch is disposed underneath the plate member 116. The other end of the latch v122 is formed with a shoulder which is of the fan.

adapted to engage a keeper 126 on the front cover 34 so as to releasably hold the front cover in the closed position shown in Fig. 2. A coil spring 127 tensioned between latch 122 and rod 118 urges the former into latching engagement with keeper 126.-

Plate member 116 is formed with an extension 128 which is disposed above a shoulder 130 formed on a pin 132, as shown in Figs. 2 and 3, which is slidably mounted in circular portion 100 of member 101 and within the space surrounded by the gasket 102. A spring 134 urges gpin 132 upwardly.

The bottom wall of inner body 22 is formed with an elongated slot 136 within which is disposed a cylindrical rail 138, the front end of which is secured to the ring 26, while the rear endis secured to the rear wall of the inner body. Slidably mounted on the rail 138 is an ejector member 149. A normally flat leaf spring 142 is disposed between the rear wall of the inner body and the ejector member and tends to move the latter towards the left,

as viewed in Fig. 2. Slidably mounted below the rail 138 is a :latch bar 144 .near the rear end of which is secured -a leaf spring 146. Ejector is formed with a lip 148 which, in the position of the .parts shown in Fig. 2; is

engaged by thespring 146. The front end of the latch bar is supported by a guide member 150 extending up- -wardly from circular portion 1110 of member 101 through the opening 104 .in the bottom wall of body 10. This end of the latch bar abuts .against the pin 132 when the latter is in its raised position so as to retain the ejector 140 in its rearward position with the spring 142 compressed. A bracket 152 carried by the rear wall of the sinner body is formed with a lower inclined surface 154 so arranged with respect to the spring 146 that movement of the latch bar 144 to the left causes the inclined surface to cam the free end of the spring 146 downwardly and out of engagement with the lip 148 of the ejector, thus releasing the latter for movement by its spring 142.

An electric switch 156 is provided for controlling a supply of current to the motor 16. This switch may be .manually actuated by means of a pivoted member 158.

'In theposition shown in Fig. 2, the switch is off and vpivoting'of the. member 158 ina clockwise direction serves to .close the switch. Slidably mounted adjacent to the switch is a bar 160 which is urged towards the left, as viewed in Fig. 2, by means of a spring 162. This bar is provided with a projection 164 which is contacted by the front cover 34 when the latter is closed so .as to hold the bar in the positionpshown. This bar is also provided with an upstanding arm 166 which is positioned so as to strike .apin 168, extending outwardly from the switch actuating member 158, whenthe latter is .in'the on position. Thus, if the switch is on and the front cover is opened, the bar 160 moves to theleft under the influence of the spring 162 and the 'arm 166 contacts pin 163 so as to automatically ,pivot member 158 counterclockwise to throw the switch .to theofi position.

Theabove described device operates as follows:

.With the parts :in .theposition shown in Fig. 2, that is witha clean dust bag in place within the body 10 and .the front .cover :34 closed, operation of .the motor-fan unit .serves todraw .air in through the inlet 52. The clean vbag offers but little resistance to the flow of air and this :air flows through the porous material of the bag and ithrough'the openings 24 of the inner body to the inlet 20 The pressure existing within the inlet passage 50 is communicated through the flexible conduit 94 .to the space in casing 62 above the diaphragm 68. The pressure existing within the inner body 10 between the .dust bag and the inlet of the fan is communicated through the passageBS and the conduit 96 to the space within the casing 62 below the diaphragm 68. Consequently, the

.diaphragm is subjected to the differential of these two small and is not sufficient to displace the dia hragm downwardly against the force of the spring 70. However, as dirt is introduced into the bag with the incoming air the dirt clogs the pores of the bag so as to increase the pressure drop therethrough, which in turn increases the differential pressure acting on the diaphragm 68 and starts to move the latter downwardly by compressing the spring 70. The more this spring is compressed the greater is the resistance which it offers to further compression. Continued downward movement of the diaphragm causes it to contact the stem 92 of valve 78, thus unseating the valve and establishing communication between the space in the casing 62 underneath the diaphragm and the space in the bore 73 between the sealing rings 36. Inasmuch as this space is permanently in communication with the power diaphragm chamber 1'96 through the conduit 110, the high suction existing underneath the pressure diffen ential diaphragm 63 is communicated to the power diaphragm chamber 106.

This causes the power diaphragm 108 and its stern 112 to move downwardly, thus pivoting the plate 116 and the rod 118. This pivotalmovement of the plate 116 causes the extension 128 thereof to move the pin 132 downwardly against the force of the spring 134. This withdraws the pin 132 from engagement with the ejector latch bar 144, thus permitting the latter to move to the left, as viewed in Fig. 2, sufiiciently for the inclined surface 154 to cam the spring 146 of the latch bar out of engagement with the lip 148 of the ejector. The ejector is thus released for movement to the left under the force of its spring 142, and it moves in this manner a short distance, but the pressure drop of the air passing through the dust bag 56 inflates the bag with such force that the bag resists further movement of the ejector.

Pivoting of the plate 116 also causes pivoting of the front cover latch 122 against the force of its spring 127 so as to release it from engagement with the keeper 126, thus permitting the spring 38 to pivot the front cover to the open position shown in Pig. 4. Opening of the front cover releases the switch actuating bar 160 for movement to the left, as viewed in Fig. 2, under the influence of spring 162. This movement causes arm 166 to strike the projection 168 on the switch actuating member 158, thus pivoting the latter so as to throw the switch to the off position. This interrupts the supply of current to the motor 16 and as the fan slows down the suction produced thereby decreases and the ejector is able to move to the left, thus ejecting the dust bag out of the cleaner and over the opened front cover 34.

With the valve assembly in the position of adjustment shown in Fig. 5, that is in its uppermost position, a minimum downward displacement of the diaphragm 68 is required to open the valve 78. This means that the automatic controls will operate upon the attainment of a minimum pressure drop through the dust bag. If it is desired that a greater pressure drop through the bag be attained before the controls operate, the knob 38 is turned counterclockwise, as viewed in Fig. 6, so that the cooperating screw threads 74 and Q0 cause the valve assembly to be moved downwardly within the bore 73. This adjustment does not vary the compression of either the diaphragm spring 70 or the valve spring 86, but it does increase the distance through which the diaphragm 68 must be displaced before it strikes the valve stem 92 to open the valve. Inasmuch as an increased displacement of the diaphragm requires an increase in the differential pressure, a greater pressure drop through the bag is now required to displacethe diaphragm sufiiciently to open the valve 78. Thus, by properly adjusting the position of the valve assembly within the bore 73, the controls may be set to operate at any desired pressure drop through the bag within the range for which the parts are constructed.

It will thus be seen that in accordance with my in vention the vacuum cleaner may be adjusted to operate properly under the different conditions found to exist in different homes. If there is a large amount of fine dust present, the knob 88 may be turned to as to lower the valve assembly, thus requiring a greater pressure drop through the dust bag before the controls operate. Likee wise, if the voltage in a particular home is higher than normal, the valve assembly may be lowered to permit a greater pressure drop through the bag, and if these conditions change from time to time the operator may readily adjust the knob 88 so as to obtain the proper operation of the cleaner.

While I have shown one more or less specific embodiment of my invention, it is to be understood that this has been done for the purpose of illustration only and that the scope of my invention is not to be limited thereby, but is to be determined from the appended claims.

What .i claim is:

l. in combination with a vacuum cleaner having a dust separating member and means for producing flow of air therethrough, a pneumatically actuated element for controlling the operation of said cleaner, a differential pressure diaphragm movable in response to variations in pressure drop of air passing through said dust separating member, a valve assembly comprising a housing having a valve seat and a movable valve member, said valve member being movable to open position by displacement of said diaphragm, manually operable means for moving said valve assembly towards and away from said diaphragm to change the displacement of said diaphragm required to open said valve, and conduit means controlled by said valve connecting said pneumatically actuated element with said means for producing flow of air.

2. In combination with a vacuum cleaner having a dust separating member and means for producing flow of air therethrough, a pneumatically actuated element for controlling the operation of said cleaner, a differential pressure diaphragm movable in response to variations in pressure drop of air passing through said dust separating member, a valve assembly comprising a housing having a valve seat, an abutment spaced a fixed distance from said seat, a movable valve member and a spring between said abutment and said valve member for urging the latter against said seat, said valve member being movable to open position away from said seat by displacement of said diaphragm, manually operable means for moving said valve assembly towards and away from said diaphragm to change the displacement of said diaphragm required to open said valve, and conduit means controlled by said valve connecting said pneumatically actuated element with said means for producing flow of arr.

3. In combination with a vacuum cleaner having a hollow body, a dust separating member therein and means for producing flow of air therethrough, a pneumatically actuated element for controlling the operation of said cleaner, a casing, a diaphragm disposed in said casing and dividing the latter into a low suction chamber and a high suction chamber, means for connecting said low suction chamber with the interior of said body ahead of said dust separating member, means for connecting said high suction chamber with the interior of said body between said dust separating member and flow producvalve, and conduit means controlled by said valve connecting said pneumatically actuated element with said means for producing flow of air.

4. In combination with a vacuum cleaner having a hollow body, a dust separating member therein andmeans for producing flow of airtherethrough, a pneumatically actuated element for controlling the operation of said cleaner, a casing, a diaphragm disposed in said casing and dividing the latter into a low suction chamber and a high suction chamber, means for connecting said low suction chamber with the interior of said. body ahead of said dust separating member, means for connecting said high suction chamber with the interior of said body between said dust separating member and flow producing means, a valve assembly comprising a housing having a. valve seat, an abutment spaced'a fixed distance from said seat, a movable valve member having a stem of fixed length and a'spring between said abutment and said valve member for urging the latter against said seat, said housing being movably mounted in a wall of said casing with said stem extending into said high suction chamber, said valve member being movable to open position away from said seat by displacement of said diaphragm against said stem, manually operable means for moving said housing in said wall towards and away from said diaphragm to change the displacement of said diaphragm required to open said valve, and conduit means controlled by said valve connecting said pneumatically actuated element with said means for producing flow of air.

5. In combination with a vacuum cleaner having a hollow body, a dust separating member therein and means for producing flow of air therethrough, a pneumatically actuated element for controlling the operation of said cleaner, a casing, a diaphragm disposed in said casing and dividing the latter into a low suction chamber and a high suction chamber, means for connecting said low suction chamber with the interior of said body ahead of said dust separating member, means for connecting said high suction chamber with the interior of said body between said dust separating member and flow producing means, a valve assembly comprising a housing having a valve seat and a movable valve member having a stem, said housing being movably mounted in a wall of said casing with said stem extending into said high suction chamber, said valve member being movable to open position by displacement of said diaphragm against said stem, manually operable means for moving said housing in said wall towards and away from said diaphragm to change the displacement of said diaphragm required to open said valve, and conduit means controlled by said valve connecting said pneumatically actuated element with said high suction chamher.

6. In combination with a vacuum cleaner having a hollow body, a dust separating member therein and means for producing flow of air therethrough, a pneumatically actuated element for controlling the operation of said cleaner, a casing, a. diaphragm disposed in said casing and dividing the latter into a low suction chamber and a high suction chamber, means for connecting said low suction chamber with the interior of said body ahead of said dust separating member, means for connecting said high suction chamber with the interior of said body between said dust separating member and flow producing means, a valve assembly comprising a housing having a valve seat, an abutment spaced a fixed distance from said seat, a movable valve member having a stem of fixed length and a spring between said abutment and said valve member for urging the latter against said seat, said housing being movably mounted in a wall of said casing with said stem extending into said high suction chamber, said valve member being movable to open position away from said seat by displacement of said diaphragm against said stem, manually operable means for moving said housing in said wall towards and away from said diaphragm to change the displacement of said diaphragm required to open said valve, and conduit means controlled by said valve connecting said pneumatically actuated element with said high suction chamber.

7. In combination with a vacuum cleaner having a =3 hollow body, a dust separating member therein and means for producing flow of air therethrough, a pneumatically actuated element for controlling the operation of said cleaner, a casing, a diaphragm disposed in said casing and dividing the latter into a low suction chamber and a high suction chamber, means for connecting said low suction chamber with the interior of said body ahead of said dust separating member, means for connecting said high suction chamber with the interior of said body between said dust separating member and flow producing means, a wall of said body which bounds said high suction chamber being formed with a bore, a valve assembly comprising a housing having a valve seat and a movable valve member having a stem, said housing being movably mounted in said bore with said stem extending into said high suction chamber and said valve member controlling communication between said high suction chamber and said bore, said valve member being movable to open position by displacement of said diaphragm against said stem, manually operable means for moving said housing in said bore towards and away from said diaphragm to change the displacement of said diaphragm required to open said valve, and conduit means connecting said pneumatically actuated element with said bore.

8.'In combination with a vacuum cleaner having a hollow body, a dust separating member therein and means for producing how of air therethrough, a pneumatically actuated element for controlling the operation of said cleaner, a casing, a diaphragm disposed in said casing and dividing the latter into a low suction chamber and a high suction chamber, means for connecting said low suction chamber with the interior of said body ahead of said dust separating member, means for connecting said high suction chamber with the interior of said body between said dust separating member and flow producing means, a wall of said body which bounds said high suction chamber being formed with a bore, a valve assembly comprising a housing having a valve seat and a movable valve member having a stem, said housing being movably mounted in said bore with said stern extending into said high suction chamber and said valve member controlling communication between said high suction chamber and said bore, said valve member being movable to open position by displacement of said diaphragm against said stern, cooperating screw' threads on said casing and on said housing whereby rotation of said housing moves the latter in said bore towards and away from said diaphragm to change the displacement of the diaphragm required to open said valve, and

conduit means connecting said pneumatically actuated element with said bore.

References Cited in the file of this patent UNITED STATES PATENTS

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