US2031911A

US2031911A - Suction cleaner

Info

Publication number: US2031911A
Application number: US675703A
Authority: US
Inventors: Donald G Smellie
Original assignee: Hoover Co
Current assignee: Hoover Co
Priority date: 1933-06-14
Filing date: 1933-06-14
Publication date: 1936-02-25
Anticipated expiration: 1953-02-25

Description

D. G. SMELLIE SUCTION CLEANER Feb. 25, 1936.

Filed June 14, 1933 2 Sheets-Sheet l ITIIIIIIIIIIII ATTORNEY I Feb. 25, 1936. s E 2,031,911

SUCTION CLEANER Filed June 14, 1953 2 Sheets-Sheet 2 ik/ g ml.

INVENTOR Donald 6". Jmellz'e ATTORNEY Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE SUCTION CLEANER poration of Ohio Application June 14, 1933, Serial No. 675,703

13 Claims.

The present invention relates to suction cleaners in general and more particularly to a new and novel motor-cooling construction in a suction cleaner. More specifically, the invention comprises a motor-cooling construction in a suction cleaner in which cooling air is drawn over the motor to the point of reduced pressure in the fan chamber, means being provided to prevent the forcing of dirt-laden air into the motor casing from the fan chamber at the termination of the 1 cleaner operation by the dust bag back pressure.

It is an object of the present invention to provide a new and novel motor-cooling construction in a suction cleaner. It is another object to pro vide motor-cooling means in a suction cleaner in which the main suction-creating fan functions to draw air over the cleaner motor. Still another object is the provision, in a suction cleaner, of a motor-cooling construction in which air is drawn from the motor casing to the eye of the fan chamber, means being provided which automatically prevent the movement of air in the opposite direction at the end of the cleaning operation. A still further object is the provision, in a suction cleaner, of passageways leading from the'motor casing to a point of high suction in the fan chamber, in

combination with means which automatically close such passageways at the end of the cleaning operation. These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawings to which they relate.

In the drawings in which preferred embodiments of the present invention are disclosed: Figure 1 is a side elevation, partly in section, of a preferred embodiment of the present invention; Figure 2 is a partial section through the motor and fan chamber with the valve in the operating or open position; Figure 3 is a rear view of the suction-creating fan; Figure 4 is a cross section through a motor casing and adjacent fan chamber showing a second preferred embodiment of the present invention; Figure 5 is a rear view of the suction-creating fan shown in Figure 4 with the valve in the operative or open position; Figure 6 is a view similar to Figure 5 with the valve in the closed or inoperative relationship; Figure '7 1 is a view similar to Figure 4 through a third preferred embodiment of the present invention; Figure 8 is a view of the back of a suction-creating fan shown in the embodiment of Figure '7 with the valves in the open or operative relationship; 55 Figure 9 is a view in perspective of the fan of Figures 7 and 8 with the valves in the inoperative or closed relationship.

Suction cleaner motors are usually enclosed and rotate at exceedingly high velocities. In order to maintain satisfactory running temperatures 6 means must be provided to draw cooling air over the motor coils to remove the excess heat. This function is sometimesa'ccomplished through the provision of an auxiliary fan within the casing of the motor itself which functions to draw air 10 in at one end of the motor casing and to exhaust it through openings at the other end. In the motor-cooling construction of the present invention an auxiliary fan is not necessary but instead motor-cooling air is drawn in at the rear end of 15 the motor casing, over the coils of the motor, through the wall common to the motor casing and the fan chamber, and through the back of the suction-creatin fan to the point of low pressure in the fan chamber which is substantially in the eye of that chamber. An opening or openings in the back of the suction-creating fan make possible the passage of air therethrough, it being preferable to provide cooperating meansin the form of a labyrinth at the periphery of the fan to pre- 25 vent the flow of air from the space between the chamber wall and the adjacent fan.

In the modern suction cleaner cleaning air is drawn through a suction nozzle, through the fan chamber, and is exhausted into a dirt receptacle such as a dust bag. The purpose of the dust bag is to remove the suspended foreign matter from the air which passes therethrough. In operation a certain pressure exists in the dust bag which is above that of the atmosphere. Upon reaching the end of the cleaning operation and the slowing down of the suction-creating fan the pressure within the dust bag recedes more gradually than that within the suction-creating fan chamber so that air is finally forced in a reverse direction into the an chamber carrying with it suspended foreign matter. Deposition of this foreign matter in small amounts in the fan chamber is not objectionable but it is necessary to prevent this air from passing rearwardly through the fan chamber, through the openings aforementioned,- and into the motor in order to protect the motor windings and commutator. In the present invention automatic centrifugally operated valves open and close said passageways. In their closed relationship the passage of air between the motor casing and the fan chamber is not permitted. In the operation of the cleaner the passage of cooling air is possible after the rotational speed of the suction-creating fan has increased to a predetermined point.

Referring again to the drawings, and Figures 1 to 3 inclusivein particular, a preferred embodiment of the present invention is disclosed. In the suction cleaner a nozzle l is interiorly connected to the fan chamber 2 at the eye 3 thereof. A motor casing 4 is positioned immediately in the rear of the fan chamber 2 being interiorly separated therefrom by a common wall 5. Front and rear supporting wheels 6 and l movably support the cleaner with the mouth of the nozzle positioned above the normal plane of the supporting surface. The exhaust outlet 8 of the fan chamber 2 opens into the dust bag 9 which is removably secured by suitable attachment means H].

The cleaner motor comprises a rotatable armature I mounted upon a rotatable shaft I2 which extends through the common casing and chamber wall 5, being supported therein by means of a ball bearing l3, into the fan chamber 2 where it carries the suction-creating fan M. The stationary motor field around the armature is indicated by the reference character IS. The motor in its general construction maybe of any well known type.

At the rearward end of the motor casing 6 is located an aperture i6 which interiorly connects the said casing to the exterior atmosphere. In the wall 5 a similar opening or openings 5 is provided which interiorly connects the motor casing to the space at the back of the fan it. Spaced peripheral flanges l7, l1 form a channel on the back of the fan in which extends the circular flange l8 formed on the wall 5. The flanges l1,

l1 and I8, together with the circular shoulder i9, formed in the casing wall 5 adjacent the outer flange l1, co-operate to form what is commonly known as a labyrinth to provide a circuitous path of relatively small cross section which air and any suspended foreign matter therein must traverse in leaving the space between the wall 5 and the back of the fan to reach the interior of the fan chamber via the fan periphery. The resistance to the flow of air through such a path provides an effective seal.

The suction-creating fan I4 is provided in its back or shroud with a plurality of

openings

20, 20 which connect the space between the wall 5 and the fan back to the inlet of the fan chamber, that is, its point of high suction and low pressure. For each of these openings a valve 2| is provided formed wi h a concave seat between its ends adapted to o erlie and seat upon a portion of the circular shoulder 22 on theback of the fan M in a manner that permits it to rock thereupon. A

split spring 23 is expanded adjacent the underside of shoulder 22 and resiliently pivots and retains each of the valves 2| in closed relationship relativeits opening. A valve in its closed position is clearly shown in Figure 1 of thedrawings, it being noted that the greater part of member-2| extends at an angle to the back of the fan and also to a line perpendicular to the axis of the rotation in this position.

Guides

24, 24 are provided for each relationship between the various parts is that shown in Figure 1 in which the'resilient spring 23 has pivoted valve member 2| about the shoulder 22 and each openingor port 20 has been closed. Upon the closing of the motor-controlling switch 2|, 2| are pivoted, under the urge of centrifugal force due to their rotation about the shaft l2, about the supporting shoulder 22 and assume limiting positions adjacent the fan back. This position is shown in Figure 2 of the drawings. So long as the speed of rotation of the fan is greater than the speedat which the valve assumed its open position no movement thereof will take place and, as is clearly seen in Figure 2, the openings 20 are unobstructed. With the

ports

20, 20, 2|! open the suction of the rotating fan is effective to draw cooling air from the motor casing, into which it has entered by way of rear opening l6. Upon passing through the openings 20, 2B, 2B the cooling air joins the dirt-laden air from the nozzle 2 and passes on to the dust bag 3.

At the end of the cleaning operation and the opening of the motor-controlling switch the speed of rotation of the motor shaft and the fan decreases. Upon diminishing to the speed at which the valves 2| moved to the open position the force exertedby spring 23 overcomes centrifugal force acting thereon and each valve again assumes its port-closing position. The point at which the valve operates, as before stated, is determined by the force exerted by the spring 23 and should be at a speed at which the exhaust pressure of the fan l4 exceeds the back pressure existing in the bag 9.

Referring now to Figures 4 to 6 a second preferred embodiment of the invention is shown in which a diiferent type of valve is used. The valve constructed in accordance with the present embodiment comprises a single plate 30 so shaped that upon limited movement radially it is adapted to assume either the open or the closed positions. The valve is held against the back of the fan M by a spring member 3| carried by the fan body adjacent thereto. Member 3| encircles the axis of rotation, as does the plate 30. At a point spaced from the axis of rotation a mass 32 is positioned on the plate and secured thereto is a spring member 33 the side arms of which extend outwardly and contact inner fan flange H to urge the plate into the closed position, or that shown I force of the mass 32 overcomes the radial force exerted by spring 33 and the plate 30 moves radially into the position shown in Figure 5, thereby opening the

passageways

20,20 et cetera and permitting the passage of air-therethrough. Upon the speed of rotation decreasing below a predetermined point the force exerted by spring 33 overcomes that exerted by weight 32 and the valve is moved to the position shown in Figure 6 and the openings 20, 2|] et cetera are closed.

Referring now to Figures '7 to 9' inclusive a third preferred embodiment of the invention is disclosed in which the valves comprise pivotally mounted

levers

35, 35,35 the movable ends of which overlie the

valve ports

20, 20, 20- in the closed relationship. Coil springs 36, 36, 36 at the pivot point of each valve normally retain the valves in the closed position, but, under the operation of centrifugal force, the movable valves are thrown outwardly, their movement being limited by stops 3? 3?, 31, the

ports

20, 20, 20 being opened and the passage of air permitted. The strength of the springs 36 in the present construction determines the opening and closing speed for the valve operation.

I claim:

1. In a suction cleaner, a cleaning nozzle, suction-creating means connected to said nozzle, a driving motor for said means interiorly connected to atmosphere, means exterior of the motor shaft connecting the interior of said motorto a point of low pressure in said suction-creating means which point is also effective in said nozzle, and means automatically to open and close said connecting means while said motor is running 'and at rest respectively.

2. In a suction cleaner, a cleaning nozzle, suction-creating means connected to said nozzle, a

driving motor for said means interiorly connected to atmosphere, air-conducting means exterior of the motor shaft connecting the interior of said motor to the point of low suction in said suction creating means which point is also effective in said nozzle, and centrifugally operated means connected to said suction-creating means to open and close said air conducting means while said motor is running and at rest, respectively.

3. In a suction cleaner, a fan chamber, a motor casing adjacent said fan chamber interiorly connected to atmosphere, a motor in said casing its shaft extended into said chamber, a suction-creating fan having a back carried by said shaft in said chamber, a passageway connecting the interior of said motor casing to said chamber at the back of said fan, means to restrict the flow of air along the back of said fan, and said fan being formed with a passageway connecting said first-mentioned passageway to the point of low pressure in said fan chamber for the purpose of drawing motor-cooling air from said easing into said fan chamber.

4. In a suction cleaner, a fan chamber, a motor casing adjacent said fan chamber, means to convey air into said casing, a motor in said casing its shaft extended into said chamber, a suctioncreating fan carried by said shaft in said chamber, a passageway connecting the interior of said motor casing to said chamber at the back of said fan, and said fan being formed with an opening connecting said passageway to a point of low pressure on its face, and automatically operated valve means controlling the flow of air from said casing and adapted to prevent said flow upon the reduction of the fan speed of rotation below a predetermined limit.

5. In a suction cleaner, a fan chamber, a motor casing adjacent said fan chamber, means to con vey air into said casing, a motor in said casing its shaft extended into said chamber, a suctioncreating fan having a shroud carried by said shaft in said chamber, air-conveying means comprising a passageway connecting the interior of said motor casing to said chamber at the back of said fan and an opening in said fan shroud connecting said passageway to a point of low pressure on its face, and valve means for. said airconveyancing means automatically opened and closed upon variations in fan speed between predetermined limits controlling the flow of air from said casing.

6. In a suction cleaner, a fan chamber, a motor casing adjacent said fan chamber, means to convey air into said casing, a motor in said casing its shaft extended into said chamber, a suctioncreating fan having a shroud carried by said shaft in said chamber, air-conveyancing means comprisifig a passageway connecting the interior of said motor casing to said chamber at the back of said fan and an opening in said fan shroud connecting said passageway to a point of low pressure on its face, and centrifugally operated valve means for said air-conveyancing means automatically opening upon said fan reaching a predetermined speed of rotation and automatically closing upon said fan decreasing its speed below a predetermined point.

7. A suction-creating rotary fan comprising a back, blades carried on one side of said back, said back being formed with an opening connecting its bladed side, at a point closely adjacent the axis of rotation, to its opposite side, and valve means to open and close said opening.

8. A suction-creating rotary fan comprising a back, blades carried on one side of said back, said back being formed with an opening connecting its bladed side, at a point closely adjacent the axis of rotation, to its opposite side, and centrifugally operated valve means rotatable with said back and blades to open and close said opening.

9. A suction-creating rotary fan comprising a back, blades carried on one side of said back, said back being formed with an opening connecting its bladed side, at a point closely adjacent the axis of rotation, to its opposite side, and a centrifugally operated pivoted valve normally held in closed relationship to said opening by a spring of such strength that said valve moves to open said opening upon said fan reaching a predetermined speed of rotation.

10. A suction-creating rotary fan comprising a back, blades carried on one side of said back, said back being formed with an opening connecting its bladed side, at a point closely adjacent the axis of rotation, to its opposite side, and a slidable centrifugal valve normally held in closed relationship to said opening by a spring of such strength that said valve moves to open said opening upon said fan reaching a predetermined speed of rotation.

11. A suction-creating rotary fan comprising a back, blades carried on one side of said back, said back being formed with an opening connecting its bladed side to its opposite side, and a centrifugally operated valve pivoted on said back about an axis parallel to the axis of rotation to open and close said opening.

12. A suction-creating rotary fan comprising a back, blades carried on one side of said back. said back being formed with an opening connecting its bladed side to its opposite side, and a centrifugally operated valve pivoted on said fan about an axis substantially perpendicular to the axis of rotation to open and close said opening.

13. In a suction-creating rotary fan comprising a back, blades carried on one side of said back, said back being formed with an opening connecting its bladed side to its opposite side, a slide valve mounted on said back to open and close said opening, spring means urging said valve to one position, said valve being movable under centrifugal force in the rotation of said fan to a second position.

- DONALD G. SMELLIE.