US2741328A

US2741328A - Automatic control unit for vacuum cleaners

Info

Publication number: US2741328A
Application number: US421481A
Authority: US
Inventors: Allen P Cawl
Original assignee: Electrolux Corp
Current assignee: Electrolux Corp
Priority date: 1954-04-07
Filing date: 1954-04-07
Publication date: 1956-04-10
Anticipated expiration: 1973-04-10

Description

3 Sheets-Sheet l w. wax V A. P. CAWL AUTOMATIC CONTROL UNIT FOR VACUUM CLEANERS o 0 0 o m w m o o 0 0 .0 wol wp w% 0 April 10, 1956 Filed April 7, 1954 April 10, 1956 A. P. CAWL AUTOMATIC CONTROL UNIT FOR VACUUM CLEANERS Filed April 7, 1954 3 Sheets-Sheet 2 INVENTOR 4((6771? Cfll/Z ORNEY April 10, 1956 A. P. CAWL 2,741,328

AUTOMATIC CONTROL UNIT FOR VACUUM CLEANERS Filed April 7, 1954 5 Sheets-Sheet 5 United States Patent AUTOMATIC CONTRGL UNIT FOR VACUUM CLEANERS Allen P. Cawl, Stamford, Conn, assignor to Electrolux Corporation, Old Greenwich, Conn., a corporation of Delaware Application April 7, 1954, Serial No. 421,481

Claims. (Cl. 183-37) This invention relates to vacuum cleaners and more particularly to such cleaners as have automatic means for controlling certain operations of the cleaner in accordance with predetermined variations in air pressure resulting from dust and dirt collected therein during use.

In a preferred embodiment of this invention a single diaphragm functions first as a differential pressure responsive member which upon continued movement opens valve means enabling pressure, either atmospheric or higher, to act positively on one surface of the differential pressure responsive diaphragm. This results in such added power that the same diaphragm functions both as a control diaphragm and as a power diaphragm. In its latter function it may be used to deenergize the motor fan unit, open the front cover, eject the dust container or merely cause the operation of a visible or audible signal.

It is another object of this invention to make the valve operated by the difierential pressure phase of the diaphragms operation adjustable so that the pressure differential at which it discontinues functioning as a difierential pressure responsive member and begins to function as a power diaphragm may be varied over a predetermined range of values. This is efiected by providing a screw threaded member having a communication to the exterior which may be raised or lowered at will to cooperate with an open central core whereby communication can be established with a further pressure source so as to predetermine the point of more positive and rapid diaphragm operation.

Further objects and additional advantages of this in vention will become obvious to those skilled in the related art upon reading the following description together with the appended drawings wherein:

Figure 1 is a side view, chiefly in section, showing a preferred embodiment of this invention; v

Figure 2 is a top plan view, somewhat enlarged, of the control unit and front cover in open position of the vacuum cleaner shown in Fig. 1;

Figure 3 is a cross-section, somewhat enlarged, taken on the line 33 of Fig. 2;

Figure 4 is a cross-section on an enlarged scale taken on the line 44 of Fig. 2, showing the valve closed; and

receiving compartment 22 shown perforated with apertures 24 for free passage of suction air current therethrough. Inner body 22 is secured at one end to front body ring 26 which in turn is secured within the open end of outer body 10.

The lower part of front body ring 26 forms the de- 2,741,328 Fatented Apr. 10, 1956 pending front wall 28 and part of the bottom of control chamber 34). Removable stamping 31 completes the enclosure of chamber 30. Front cover 34 is hinged by pin 36 to a pair of projections 32 extending from the wall 28 and is biased to open position by spring 38. A hose coupling assembly 42 is pivotally mounted by pins 44 in the opening 40, Fig. 2, formed in the cover. Link 48 pivotally connected to the hose coupling assembly at one end and to a projection 32 at the other end forms a parallel motion linkage which causes the hose coupling assembly 42 to move parallel to itself upon opening and closing the cover 34.

Hose coupling assembly 42 effects an airtight seal with front body ring 26 by means of the stiff cardboard disc 58 of dust bag or dust separating member 56 with the aid of gasket 54 bearing against the disc 58 while theedges of disc 58 seal against gasket 60 carried by front body ring 26. Tubular member 52 of hose coupling assembly 42 extends through a centrally disposed opening in disc 58 when the cover is in the closed position shown in Fig. l in order to introduce the air and entrained dust directly into the interior of dust bag 56.

A differential pressure diaphragm housing 64 secured below body 10 by a plurality of bolts 62 forms a combined control unit and power diaphragm actuating member. Secured within housing 64 is a pressure differential diaphragm 68, Figs. 4, 5, which divides the housing into an upper high vacuum chamber '70 and into a lower low vacuum chamber 72. Chamber 7% is connected to the interior of body 10 through an opening 74 in the body housing 10. The edges of diaphragm 6S bear against the bottom of body 16 and housing 64 seals against diaphragm 68 to prevent leakage.

A flexible conduit 88 connects the lower chamber 72 and a passage in the hose connector 42 to subject the lower surface of the diaphragm 68 to the pressure existing within or ahead of the bag 56, while the upper surface of diaphragm 68 is subjected to the pressure existing within the body iii between the bag and the fan unit, except when the pressure in chamber 72 is modified by atmospheric pressure or other pressure introduced by the opening of valve means in member 114 described below.

Spring 92 is disposed between the upper surface of diaphragm 68 and the lower wall of body 10. Diaphragm 68 carries a stem and secured to the lower end of this stem 110 is a valve member 112 which controls the flow of atmospheric pressure or other pressure from port 113 through a bore 111 connecting the interior of hollow member 114 with low suction chamber 72. Hollow member 114 is adjustably mounted by threads 115 so as to raise and lower the position of port 113 with respect to sealing valve member 112.

Within the body 14 adjacent to opening 74 is a bracket 116 in which is pivotally mounted a pin 134 carrying a rocker arm 118 one end of which is disposed above the stem 110 of the diaphragm 68. The other end of arm 118 bears against a pin 120 slidably mounted in the bracket 116. The lower end of pin 124 bears against the inner end of front cover latch 122 which is pivotally mounted on wall 28 at 124. The outer end of latch 122, Fig. 4, is formed with a shoulder 123 which is adapted to engage a keeper 134 mounted on the front cover 34 so as to retain the cover in closed position. A spring 132 urges the latch arm 122 towards the position shown in full lines in Fig. 4. I Oneend of pin 134 extends to one side of bracket 116, where it is provided with a cam 136. This cam bears against a leaf spring 133, one end of which is secured to the bottom wall of housing 10, while the free end of the spring carries a stop 140.

The bottom wall of inner body 22 is formed with 3 an elongated slot 142, Fig. 1, in which is disposeda cylindrical rail 144, the front end of which is secured to the ring 26, while the rear end is secured to the rear wall of the inner body. Slidably mounted on the rail 144 is an ejector member 146. A normally flat leaf spring 148 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. l. Slidably mounted below the rail 144 is a latch bar 150 near the rear end of which is secured a leaf spring 152. Ejector 146 is formed with a lip 154 which, in the position of the parts shown in Fig. l, is engaged by the spring 152. The front end of the latch bar 150 abuts against the stop 140 so as to retain the ejector 146 in its rearward latched position with the spring 148 compressed. A bracket 1S6 carried by the rear wall of the inner body is formed with a lower inclined surface 158 so arranged with respect to the spring 152 that movement of the latch bar 150 to theleft causes the inclined surface to cam the free end of the spring 152 downwardly and out of engagement with the lip 154 of the ejector, thus releasing the latter for movement by its spring 148.

An electric switch 160 is provided for controlling the supply of current to the motor 16. 'This switch may be manually actuated by means of a pivoted member 162. In the position shown in Fig. l, the switch is off and pivoting of the member 162 in a clockwise direction serves to close the switch. Slidably mounted adjacent the switch 172 extending outwardly from the switch actuating member 162 when the latter is in the on position. Thus, if the switch is on and the front cover is opened, the bar 164 moves to the left under the influence of its spring 166 and arm 170 contacts pin 172 so as to throw the switch automatically to the off position.

The above described control device operates as follows:

With parts in the position shown in Fig. 1, that is with a clean dust bag in 'place within the body and the front cover closed, operation of the motor-fan unit serves to draw air in through the inlet 52. This air passes with but little resistance through the porous material of the bag and through the many openings 24 of the inner body to the inlet 20 of the fan 14. The pressure existing within the inlet is communicated through the opening 90 and conduit 88 to the chamber 72 below the pressure diiferential diaphragm 68. The pressure existing "within the inner body between the bag and the inlet of the fan is communicated to the chamber 70 above the diaphragm 68 through the opening 74. Thus diaphragm 68 is subjected to the differential pressure resulting from these two pressures, which corresponds to the pressure .drop through the dust bag. When the bag is clean there is but little pressure drop through it and consequently this different'ial is very small and is not suflicient to displace the diaphragm upwardly against the force of the spring 92.

However, as more and more dirt is introduced into the bag with the incoming air, it is retained within the bag and gradually clogs the pores thereof so as to increase the pressure drop. This of course increases the differential pressure acting on the diaphragm 68 and starts to raise the latter by compressing the spring 92. The more'th'is spring is compressed the greater is the resistance which between the low vacuum chamber 72 and the at mosphere or some other source of positive pressure. This causes the difierential pressure diaphragm 68 to move quickly and more powerfully to its upper limit, 'thus functioning as a power diaphragm. With the device of this invention high vacuum is always applied directly to the upper surface of diaphragm 68.

Upwardmovement of the power diaphragm causes its stem 110 to pivot the arm 118 in a counterclockwise direction, as viewed in Fig. 4. This depresses the pin 120 which in turn pivots the latch 122 in clockwise direction so as to disengage it from the keeper of the front cover. The spring 38 thereupon opens the cover and when this occurs the projection 168 on the bar 164 is released and the spring 166 moves the bar to the left, as seen in Fig. 1, thus moving the switch member 162 to its off position, which stops the operation of the motor-fan unit.

Pivoting of the arm 118 causes pin 134 to turn in a counterclockwise direction, as viewed in Fig. 3, thus causing cam 136 to depress the spring 138, which with draws the stop 140 from contact with the left end of the ejector latch bar 150. As the right-hand .end of this bar is coupled to the ejector through engagement of the leaf spring 152 with the lip 154, the release of latch bar causes ejector spring 148 to move both the ejector 146 and the bar 150 to the left. The inclined surface 158 on the bracket 156 thereupon cams the spring 152 down wardly and out of engagement with the lip 154, whereupon the ejector is freed to move all the way to the left, pushing the bag ahead of it and out of the cleaner.

By adjusting the relative positions of valve 112 with respect to port 113 a greater or lesser pressure drop through the bag will be required in order to establish the pressure differential necessary to cause diaphragm 68 to open valve 112. The lower hollow member 114 is adjust-able with respect to housing 64 by virtue of its threaded connection 115. Thus the lower port 113 is dis placed by screwing the hollow member outwardly, the lower will be the pressure differential or drop through the bag required to open valve 112 and admit positive pressure to chamber 72.

It is to be understood that the embodiment herein specifically described is merely illustrative and that the scope of the invention is to be limited solely by the suction chamber and a high suction chamber, conduit means for connecting said low suction chamber to a point in said casing ahead of said dust separating means, conduit means for connecting said high suction chamber with a point in said casing between said dust separating means and said suction producing means, valve means openable by displacement of said diaphragm in a direction towards said high suction chamber to establish communication between said low suction chamber and a region of higher pressure for decreasing the suction in saidlow suction chamber to further displace said diaphragm in said direction, and means responsive to the further displacement for controlling said vacuum cleaner.

2. in combination with a vacuum cleaner having a casing enclosing dust separating means and suction proit' offers to further compression and the spring is so selected with respect to the area of diaphragm 68 that the diaphragm will open the valve 112 when the pressure drop through the bag has attained a value such that continued operation of the cleaner would be inefiicient.

When diaphragm 63 moves high enough to lift the lower seal of valve 112 above port 113, as in ,Fig. 5, cornrnunication is established through the bore 111 of stem ducing means for causing how of air therethrough, a housing, a diaphragm dividing said housing into a low suctic'm chamber and a high suction chamben'conduit means for connecting .said low suction chamber to .apo'int in said casing ahead of said dust separating means, conduit means for conn cting said high suction chamber wlitha point in said casing between said dust separating means and said suctionproducing means, valve means opcnable by a predetermined displacementof sa'id diaphragm in a direction towards said high suction chamber to establish communication between said low suctionw chamber and a region of higher pressure for decreasing the suction in said low suction chamber to further displace said diaphragm in said direction, means responsive to the further displacement for controlling said vacuum' cleaner, and manually adjustable means for varying the displacement of said diaphragm required to open said valve means.

3. In combination with a vacuum cleaner having a casing enclosing dust separating means and suction producing means for causing flow of air therethrough, a housing, a diaphragm dividing said housing into a low suction chamber and a high suction chamber, conduit means for connecting said low suction chamber to a point in said casing ahead of said dust separating means, conduit means for connecting said high suction chamber with a point in said casing between said dust separating means and said suction producing means, a hollow member having a port connecting the interior of said member with a region of higher pressure, a stem extending into said hollow member and being movable by displacement of said diaphragm in a direction towards high suction chamber to establish communication between said port and said low suction chamber for decreasing the suction in the latter to further displace said diaphragm in said direction, and means responsive to the further displacement for controlling said vacuum cleaner.

4. In combination with a vacuum cleaner having a casing enclosing dust separating means and suction producing means for causing fiow of air therethrough, a housing, a diaphragm dividing said housing into a low suction chamber and a high suction chamber, conduit means for connecting said low suction chamber to a point in said casing ahead of said dust separating means, conduit means for connecting said high suction chamber with a point in said casing between said dust separating means and said suction producing means, a hollow member having a port connecting the interior of said member with a region of higher pressure, a stem extending into said hollow member and being movable by displacement of said diaphragm in a direction towards said high suction chamber to establish communication between said port and said low suction chamber for decreasing the suction in the latter to further displace said diaphragm in said direction, means responsive to the further displacement for controlling said vacuum cleaner, and means for adjusting the position of said hollow member with respect to said stem to vary the displacement of said diaphragm required to establish said communication.

5. In combination with a vacuum cleaner having a casing enclosing dust separating means and suction producing means for causing flow of air therethrough, a housing, a diaphragm dividing said housing into a low suction chamber and a high suction chamber, conduit means for connecting said low suction chamber to a point in said casing ahead of said dust separating means, conduit means for connecting said high suction chamber with a point in said casing between said dust separating means and said suction producing means, a hollow member having a port connecting the interior of said member with a region of higher pressure, a stem secured to said diaphragm and extending into said hollow member and normally closing said port, said stem having a bore connecting the interior of said hollow member with said low suction chamber, said stem being movable in said hollow member by displacement of said diaphragm in a direction towards said high suction chamber to open said port and establish comunication from the port through said bore to said low suction chamber for decreasing the suction in the latter to further displace said diaphragm in said direction, and means responsive to the further displacement for controlling said vacuum cleaner.

6. In combination with a vacuum cleaner having a casing enclosing dust separating means and suction producing means for causing flow of air therethrough, a housing enclosing said diaphragm dividing said housing into a low suction chamber and a high suction chamber, conduit means for connecting said low suction chamber to a point in said casing ahead of said dust separating means, conduit means for connecting said high suction chamber with a point in said casing between said dust separating means and said suction producing means, a hollow member having a port connecting the interior of said member with a region of higher pressure, a stem secured to said diaphragm and extending into said hollow member and normally closing said port, said stem having a bore connecting the interior of said hollow member with said low suction chamber, and said stem being movable in said hollow member by displacement of said diaphragm in a direction towards said high suction chamber to open said port and establish communication from the port through said bore to said low suction chamber for decreasing the suction in the latter to further displace said diaphragm in said direction, means responsive to the further displacement for controlling said vacuum cleaner, and means for adjusting the position of said hollow member with respect to said stem to vary the displacement of said diaphragm required to cause said stem to open said port.

7. In a vacuum cleaner, a casing, dust separating means and suction producing means disposed in said casing, a diaphragm housing secured to said casing, a diaphragm dividing said casing into a high suction chamber and a low suction chamber, said casing being formed with an opening from said high suction chamber into a space within said casing between said dust separating means and said suction producing means, means for establishing communication between said low suction chamber and the interior of said casing ahead of said dust separating means, a hollow member secured to said diaphragm housing and communicating with said low suction chamber and having a port opening to atmosphere outside said casing, a stem secured to said diaphragm and extending into said hollow member and normally closing said port, said stem having a bore connecting the interior of said hollow member with said low suction chamber, said stem being movable by displacement of said diaphragm towards said high suction chamber to open said port to admit air at atmospheric pressure to said low suction chamber for decreasing the suction therein to further displace said diaphragm in said direction, and means responsive to the further displacement for controlling said vacuum cleaner.

8. In a vacuum cleaner, a casing, dust separating means and suction producing means disposed in said casing, a diaphragm housing secured to said casing, a diaphragm dividing said casing into a high suction chamber and a low suction chamber, said casing being formed with an opening from said high suction chamber into a space within said casing between said dust separating means and said suction producing means, means for establishing communication between said low suction chamber and the interior of said casing ahead of said dust separating means, a hollow member having an open end in threaded engagement with said diaphragm housing and communieating with said low suction chamber, said hollow member having a port opening to atmosphere outside said casing, a stem secured to said diaphragm and extending into said hollow member and normally closing said port, said stem having a bore connecting the interior of said hollow member with said low suction chamber, said stem being movable by displacement of said diaphragm towards said high suction chamber to open said port to admit air at atmospheric pressure to said low suction chamber for decreasing the suction therein to further displace said diaphragm in said direction, and means responsive to the further displacement for controlling said vacuum cleaner, said hollow member being accessible for manual rotation to adjust its position axially with respect to said stem to shun-see" vary the displacement, of said diaphragm necessary to cause said stem to open said port. a

9, In a vacuum cleaner, a casing, dust separatingmeans and suction producing means disposed in a space in said casing, ejector mechanism disposed in said space and releasable for ejecting said dust separating means from said casing, a diaphragm housing secured to said casing, a; diaphragm dividing said easing into a high suction chamber and a low suction chamber, said casing being formed with an opening from said high suction chamber into a space within said casing between said dust separating means and said suction producing means, means for establishing communication between said low suction chamber and the interior of said casing ahead of said dust separating means, a hollow member secured to said (Ha pbragm'housing and communicating with said low suction chamber and having a port to a region of higher pressure, a stemsecured to said diaphragm and extending into said hollow member and normally closing said port, said stem having a bore connecting the interior of said hollow member with said low suction chamber, and said stem being movable by displacement ot' 'said diaphragm towards said high suction chamber to open said port to admit air from said region of higher pressure to said low suction chamber for decreasing the suction therein to further displace saiddiaphragm in said direction, a rod extending sing diaphragm, ,aivr s chamber into a spacelwithin said casingfbetween said dust separating means and said suction producing means, a means for establishing communication between said low suction-chamber and the interior of said casing ahead of said dust separating'means, a hollow member having an open end in threaded engagement with said diaphragm housing and communicating with said low suction chamher, said hollow, member having a port to a region of higher pressure in the side thereof, a stem secured to said diaphragm and extending into said hollow member and normally closingsaid port, said stem having a bore connecting the interior of said hollow member with said low suction chamber, said stem being movable by displace mechanism, said hollow member being accessible =formanual rotation to adjust its position axially with respect to said stem to vary the displacement of said diaphragm necessary to cause said stem to open said port.

References Cited in the file of this patent STATES PATENTS 2,569,222 "Beede et al. Sept. '25, 1951 FOREIGN PATENTS Great Britain Dec. ll, 1931 said casing into saga, suction chamber and a low suction chamber, said casing being formed with .an opening from said high suction