US1020310A - Vacuum-cleaner. - Google Patents

Description

W. H. RAKESTRAW.

VACUUM CLEANER.

APPLICATION IILBD MAR.7, 1911.

Patented Mar. 12, 1912.

2 SHEETS-SHEET 1.

wi imwoe-o W. H. RAKESTRAW.

VACUUM CLEANER.

APPLICATION FILED MAR. 7, 1911.

Patented Mar. 12, 1912.

2 SHEETS-SHEET 2.

NITED STATES PATENT OFFICE.

WILLIAM H. RAKESTRAW, OF BLOOMINGTON, ILLINOIS, ASSIGNOR T0 AUTOMATIC VACUUM CLEANER COMPANY, OF BLOOMINGTON, ILLINOIS, A CORPORATION OF ILLINOIS.

VACUUM-CLEANER.

Specification of Letters Patent.

Application filed March 7, 1911.

Patented Mar. 12, 1912.

Serial No. 612,814.

To all whom it may concern.

Be it known that I, VILLIAM II. RAKE- S'IRAW, a citizen of the United States, residing at Bloomington, in the county of Mc- Clean and State of Illinois, have invented certain new and useful Im rovements in I acuum-Cleaners, of which t e following is a specification.

This invention relates to vacuum cleaners, more particularly to that class thereof known as portable vacuum cleaners, and is in part an improvement upon my contemporaneously pending application Serial No. 585,193, filed October 4:, 1910, the object of the invention being to provide a power, such as a motor driven, machine in which the motor will be so supported and connected with the pumping mechanism that vibration thereof will be reduced to a minimum, and in which the inlet and outlet valves will be so located in connection with this improved form of pumping mechanism that a more positive and efficient operation thereof is obtained.

A further object of the invention is the provision of an improved vacuum cleaner embodying a pair of pumps spaced apart and operated in unison both to draw in air simultaneously at one time and to expel the same simultaneously at another time by driving means, preferably in the form of a motor, located between the pumps, this organization permitting the proper balancing of the driving means and eliminating substantially all vibration of the machine, and in which organization one of such pumps will be provided with an inlet valve mechanism and the other with an outlet valve mechanism so constructed and located that both of the valves will seat by gravity, thus obviating the use of springs to assist the seating of the valves and preventing the blowing back of the air through the valve before it seats.

In vacuum cleaning machines in which one or both of the valves seat upwardly such valves do not act quickly enough unless springs or other means are used to assist in the seating of thevalvcs, and in consequence the proper amount of air is not displaced, as a part of such air blows back through the valves before they seat. The use of springs, however, to prevent this is objectionable,

and substantially all vibration eliminated,

while at the same time the valves are so formed and located that they will seat by gravity, thus obviating the necessity of using leather stretched over a convex surface or springs to assist in the seating of the valves, while at the same time providing a very simple and comparatively inexpensive and highly etlicient vacuum cleaning apparatus, which may also be used effectively not only to suck in dirt but as a blowing apparatus.

In the drawings accompanying and forming part of this specification, Figure 1 is a vertical sectional view of this improved vacuum cleaner; Fig. 2 is a perspective view of the upper pumping chamber and the outlet valve detachcd from the machine; Fig. 3 is a perspective view of the lower pumping chamber likewise detached from the machine, with the connecting air passages broken away; Fig. 4 is a side elevation of one form of dirt separating means and which forms a part of the vacuum chamber; and Fig. 5 is partly a side elevation and partly a sectional view of this improved machine.

Similar characters of reference indicate corresponding parts throughout the figures of the drawings.

In the preferred form thereof herein shown and described, this improved portable vacuum cleaner comprises a suitable base 2 provided with some suitable form of casters 3 whereby it may be readily moved around the room or from one place to another. This base has an upwardly extending annular flange L for the reception of a cylindrical casing 5 provided with handles 6. This casing or receptacle is secured to the base by suitable fastening devices. A cover 10 provided with a suitable handle 11 closes the upper end of this cylindrical casing, it being secured thereto by suitable locking devices 12. The casing is provided with a suitable opening 13 for the attachment of the inlet suction hose and nozzle. This casing is divided between its ends by a horizontally located partition 14: forming a pair of compartments or chambers 15 and 16, one, as 15, constitutingto a certain extent what may be considered a vacuum reservoir or chamber in which a suitable dirt separating means may be located, and the other, as 16, constituting an exhaust chamber in which the pumping mechanism and driving means are located. In the present instance, however, the dirt separating means is shown in the form of a receptacle 18 located within the chamber 15 and in communication with the inlet opening of the chamber 15. This receptacle is in the form of a metal can 19 having adjacent to its top a pair of outlets 2O communicating with tu bular passageways 21 formed on the outer side of the can, the lower ends of which tubular passageways are in communication with a pair of tubes 35 hereinafter described. Located within this receptacle or can is a suitable dirt separating means, shown in the form of a bag 22, which in the present instance is substantially the same as that shown in my contemporaneously pending application hereinbefore referred to and a further description thereof is therefore deemed unnecessary. The receptacle is provided with a cover 23 securely clamped thereto in substantially the same manner as shown in my contemporaneously pending application. This dirt receptacle in the present construction of machine thus forms the vacuum chamber or reservoir, although it will be obvious that this receptacle could be dispensed with and the upper compartment of the casing constitutes the vacuum reservoir or chamber and support any suitable dirt separating means which it may be desired to use.

In the present instance it will be observed that the dirt and dust is drawn into the vacuum chamber at the. outer side of the bag, so that it tends to settle by gravity in the can below the bag, while the purified air passes through the bag from the outer sides thereof to the outlet openings hereinbefore described.

In my contemporaneously pending application hereinbefore referred to the pumping mechanism is similar in some respects to that shown herein. In that case, however, the air is drawn in from one pump chamber to another through tubes and is expelled through the same tubes and the inlet valve and the outlet valve mechanism is located in the upper pump chamber, in consequence of which t is impossible that both valves seat by gravity. In the present instance, while the pumps are spaced apart in a similar manner to.

that shown in my prior application, the air is drawn in through one set of tubes and expelled through another, while the inlet valve is located in the lower pump chamber and the exhaust valve in the upper pump chamber, thusenabling not only both valves to seat by gravity, but a somewhat more eflicient operation of the cleaner.

The pumping mechanism located in the exhaust chamber of the casing comprises a pair of pumps 24 and 25, each consisting of an air chamber, one, as 24, being supported by and adjacent to the base of the machine, and in practice it is preferably formed as an integral structure therewith. The upper air chamber, as 25, is spaced apart from and in the present instance is supported above the lower air chamber by a plurality of tubes 26. The lower chamber 24; is closed at its upper side by a suitable diaphragm formed of any suitable material, the outer edge thereof being secured to the base of the machine by a suitable clamp ing ring. This lower chamber 24 is formed with an annular shoulder or wall 27 for the reception of the valve, which in the present instance forms the inlet valve of the pumping mechanism. This valve consists simply of a disk 28 of some suit-able material having a plurality of elongated arc-shaped slots 29 on which is laid an annular member 30 constituting the valve proper. This member may consist of any suitable material, but is shown in the present instance as made of three thicknesses of leather glued or otherwise secured together, it being held in proper position by suitable U-shaped brackets or members 31 so that the valve will not lift too far from its opening. It will thus be observed that the valve seats itself by gravity, it being lifted by the action of the pump to permit the ingress of air in the manner hereinafter described. The lower side of the upper pump chamber is likewise provided with a similarly formed diaphragm 33, while the opposite or uppermost side of such chamber is provided with a similarly formed valve 32 carried by a similar disk to that hereinbefore described, the valve being located at the upper side of the disk and in the position shown in Fig. 2, so that it likewise seats itself by gravity. This valve constitutes the outlet or exhaust valve of the pumping mechanism.

As hereinbefore stated, the two pumps are connected by air passages in the form of tubes. In the present instance two of these tubes, as 35, communicate with the lower pump chamber at the lower side of the valve, while the upper ends thereof are in communication with the tubes 21 of the dirt separating can or vacuum chamber, for which purpose the partition 14: hereinbefore referred to dividing the easing into a vacuum chamber and an exhaust chamber is provided with openings 36 around which will be provided suitable packing so that the communication between the tubes 21 and 35 will be air-tight. The remaining tubes, preferably shown as four in number, communicate with the lower pump chamber at the upper side of its valve and with the upper pump chamber at the underside of the upper valve. All of these tubes may be removable and in the present instance they are shown as fitting into sockets formed in the rings by means of which the diaphragms are secured in position on the castings -forming respectively the base of the machine and the upper pump chamber, and which castings are provided with housed or closed ports 40 in communication with the ends of the tubes, excepting those two ports which communicate with the tubes 21 of the vacuum chamber, which ports are open at their undersides for the reception of the tubes 35 and at their upper sides for communication with the tubes 21 of the vacuum chamber. By providing a pair of inlet air passages, as 21 and 35, the intake of air is more evenly and properly balanced and by providinu a plurality of tubes oppositely disposed t is exhaust of the air is likewise more evenly balanced. These tubes likewise form pillars for supporting the two pumps spaced apart one above the other and in linear alinement with the vacuum chamber and with the driving mechanism. The exhaust valve carried by the upper pump opens into the casing below the horizontal partition thereof, so that the air is expelled or exhausted into this casing, from which it passes by a port- 42 located in the base of the machine, which port is shown as an elongated slot formed in the base of the machine in communication with the outside of such base and to which may be attached a hose if it is desired to use the machine as a blower.

Each of the pump chambers is formed as a casting, the lower pump being formed as an integral part of the base, as hereinbefore stated, while the upper pump is supported by the tubes hereinbefore described, the two pumps being connected by suitable rods 44: and nuts 45, whereby the two pumps are held together and in tight engagement with the air tubes;

From the foregoing it will be observed that the air or pump chambers are supported by a plurality of tubes, a pair of which serve as the air intake tubes communicating with the vacuum chamber and with one of said pumps, while the remainder connect the two pumps together and serve as air exhaust passages, so that in the operation of the pumps air will be sucked in from the vacuum chamber through the intake tubes into the lower compartment of the lower pump, from whence it passes through the valve into the upper compartment of such pump and from thence through the air exhaust tubes to the upper pump below the valve, and from thence through the valve into the casing surrounding the pumping mechanism and out therefrom into the atmosphere, so that in the present improvement certain of the tubes act as the air intake tubes, while the remainder act as the air exhaust tubes, thus providing a very eflicient pumping mechanism.

Supported on suitable posts 50 carried by the base is a motor supporting member or platform 51 adapted to support the driving mechanism, such as an electric motor 53. This platform extends from side to side of the base above the lower diaphragm, the posts 50 raising it sufliciently above the base to give free and proper action to the diaphragm. Any suitable form of motor adapted for the purpose may be used. On each end of the shaft 54: of the motor is located a pair of eccentrics 55 and 56 disposed side by side, the eccentric portion of one of such eccentrics being diametrically opposite to the eccentric portion of the other eccen tric. Located on each of, these eccentrics is a strap 57 having a connecting rod 58, so that the connecting rods of the pumps extend in opposite directions, or one of each pair down and one up in the present arrangement of the machine. The outer end of each connecting rod is pivotally connected to a diaphragm, and for this purpose each diaphragm is provided centrally with a head or ring 60, to which the diaphragm is secured, and this ring is provided with oppositely located alined studs or pivots 61 pro jecting into bearings 62 on the rods. By this organization it will be observed that both diaphragms of the two air or pump chambers are moved in unison at one time toward each other and at another time away from each other, so that both pumps operate simultaneously to draw in air at one time and simultaneously to expel such air at another time, and as the motor is supported between these two pumps and connected therewith by means of the diametrically opposed connecting rods it will be observed that the mechanism is balanced and vibration of the motor is avoided. Some suitable form of antifriction bearings will be located between the connecting rod straps and the eccentrics of the motor shaft.

It will of course be understood that suitable packing will be used at those points where such is required, but "cry little of such packing is required in the present construction of machine by reason of the manner in which it is organized and constructed.

In order that the inlet tubes 35 may communicate with the lower compartment of the lower pump chamber the ports in the casting into which these tubes project are formed of greater length than the ports into which the tubes forming the exhaust set of tubes project, so that the first pair of ports will thus open into the lower compartment of the pump below the valve.

In operation the dirt and dust drawn through the nozzle renovator, not shown, and the suction hose, not shown, enters the dirt and dust separator or vacuum chamber at the outer side of the bag or other separating material, where, as hereinbefore stated, the larger proportion of the dust and dirt settles in the vacuum chamber, the purified air passing through the walls of the bag and through the two outlet tubes 21 and from thence through the tubes 35 to the lower compartment of the lower pump and through the valve into the upper compartment of such pump, and therefrom through the outlet or exhaust tubes into the upper pump chamber below the valve. On the next stroke of the pumps the air remaining in the upper compartment of the lower pump and in the air chamber of the upper pump is expelled therefrom through the valve of the upper pump on the opening of the same by the action of the pump and into the casing surrounding the pumping mechanism, from which it is forced into the atmosphere. Thus it will be observed that on the inward movement of both diaphragms toward the motor air is drawn in through the inlet valve in the lower pump chamber to the two pump chambers, one above this valve and the other below the upper valve, while on both outward strokes of the diaphragm this same air is expelled or forced out through the upper or outlet valve of the upper pump chamber, both pumps thus operating in unison from the same shaft, so that by placing the pumps opposite to each other and one at each side of the power the pumping mechanism is perfectly balanced on the driving shaft and all vibration is overcome, and not only this, but less power is required to dis place the same amount of air, as the eccentrics are only offset from the center about half of what would be necessary in a machine with one pump located at one side thereof, and at the same time the valves of both pumping chambers seat themselves by gravity, a very desirable and highly efficient construction. The motor is electrically connected with the base in some suitable manner whereby on the insertion of the usual plug carrying the cord the cleaner may be thrown into operation on the operation of the proper switch.

I claim as my invention:

1. In a vacuum cleaning apparatus, the

combination with a casing having a vacuum chamber, of vacuum creating means connected therewith and comprising a pair of diaphragm air pumps spaced apart and operative simultaneously and in unison both to draw in or to expel air, an electric motor located between and connected with each of the pumps to operate them in unison and simultaneously, hollow pillars supporting said pumps spaced apart and forming a plurality of air passages, one or more connecting the vacuum chamber with one of the pumps for the air intake and one or more different air passages connecting said pumps for the air exhaust, and a gravity seating valve for each of said pumps,'one controlling the admission of air to both of the pumps and the other the exhaust of air from said pumps, the air passing from the vacuum chamber to one pump and from thence to the other pump and then into the casing.

2. In an exhaust chamber a vacuum cleaning apparatus, the combination of a vacuum chamber, a vacuum creating means connected with the vacuum chamber and comprising a pair of pumps spaced apart, driving means located within said exhaust chamber and between said pumps and operating the pumps in unison simultaneously to draw in or expel air, said pumps having a plurality of air passages one or more forming an air intake passage and one or more connecting said pumps and forming an air exhaust passage, and valve mechanism separating one of said pumps into a pair of compartments, the valve thereof seating by gravity.

3. In a vacuum cleaning apparatus, the combination of a vacuum chamber, a vacuum creating means connected therewith and comprising a pair of pumps spacedapart, driving means located between said pumps and operating the pumps in unison simultaneously to draw in or expel air, said pumps having a plurality of air passages one or more forming an air intake passage and one or more connecting said pumps and forming an air exhaust passage, valve mech anism separating one of said pumps into a pair of compartments, and valve mechanism in the other of said pumps, one of said valve mechanisms controlling the intake of air and the other the exhaust thereof and the valves of both mechanisms seating by gravity, the exhaust air passing through both of said pumps before its discharge from one of them.

4. In a vacuum cleaning apparatus, the combination of a vacuum chamber, a vacuum creating means connected therewith and comprising a pair of pumps spaced apart one above the other, a motor located between said pumps and operating the pumps in unison simultaneously to draw in or expel air, valve mechanism connected with each of said pumps, one of said valve mechanisms separating one of said pumps into a pair of con'ipartments, an air pas sage or passages connnunicating with the vacuum chamber and with a compartment of one of said pumps, and an air passage or passages communicating with the other compartment of said pump and with the other pump.

5. In a vacuum cleaning apparatus, the combination of a vacuum chamber, a vacuum creating means connected therewith and comprising a pair of pumps spaced apart one above the other, a motor located between said pumps and operating the pumps in unison simultaneously to draw in or expel air, valve mechanism connected with each of said pumps, one of said valve mechanisms separating one of said pumps into a pair oi compartments, an air passage or passages communicating with the vacuum chamber and with a compartment of one of said pumps, an air passage or passages communicating with the other compartment of said pump and with the other pump, and a valve connected with each of said pumps and respectively controlling the intake and exhaust of air, each of said valves seating by gravity.

6. In a vacuum cleaning apparatus, the

combination of a vacuum chamber, a vacuum creating means connected therewith and comprising a pair of pumps spaced apart, a motor located between said pumps and opcrating the pumps in unison simultaneously to draw in or expel air, hollow pillars supporting said pumps spaced apart one or more communicating with the vacuum chamber and with one of said pumps and forming an air intake passage and one or more connecting said pumps together and forming an air exhaust passage, and a "alve connected with each of said pumps one separating one of said pumps into a pair of compartments and the intake passage from the exhaust passage. '7. In a vacuum cleaning apparatus, the combination of a supporting base, a vacuum pump located therein, a valve separating said pump into a pair of compartments, pillars supported on said base and forming air passages one or more in communication with one of said compartments and one or more in communication with the other of said compartments, a pump supported by said pillars and with which one or more of said air passages are in communication, a vacuum chamber in communication With one or more of said air passages, a valve connected with said last pump, and a motor also supported by said base and located between said pumps and connected therewith for driving said pumps in unison simultaneously to draw in or expel air.

8. In a vacuum cleaning apparatus, the

combination of a supporting base, a vacuum pump located therein, a valve separating said pump into a pair of compartments, pillars supported on said. base and forming air passages one or more in communication with one of said compartments and one or more in conmiunication with the other of said compartments, a pump supported by said pillars and with which one or more of said air passages are in communication, a vacuum chamber in communication with one or more of said air passages, a valve connected with said last pump, a motor also supported by said base and located between said pumps and connected therewith for driving said pumps in unison simultaneously to draw in or expel air, and a casing also supported by said base and surrounding the pillars and motor and into which the exhausted air is expelled, said casing lnwing an outlet.

9. In a vacuum cleaning apparatus, the combination of a supporting base, a vacuum pump located therein, a valve separating said pump into a pair of compartments, pillars supported on said base and forming air passages one or more in communication with one of said compartments and one or more in communication with the other of said ernnpartments, a pump supported by said pillars and with which one or more of said air passages are in comnnmication, a vacuum chamber in con'imunication with one or more of said air passages, a valve connected with said last pump, a motor also supported by said base and located between said pumps and connected therewith for driving said pumps in unison simultaneously to draw in or expel air, and a casing also supported by said base and surrounding the pillars and motor and into which the exhausted air is expelled, said casing having an outlet, and said casing also having a partition separating said vacuum chamber from the pumping mechanism.

10. In a vacuum cleaning apparatus, the cond ination of a supporting base, a pump therein, a diaphragm for said pump, an inlet valve in said pump and separating the same into a pair of: compartments and seating by gravity, hollow supporting pillars carried by said base and forming air passages, a pump supported by said pillars and having a diaphragm, an exhaust valve connected with said pump and seating by gravity, some of said pillars connecting the upper compartment of the lower pump and the upper pump and some of said pillars communicating with the lower compartment of said lower pump, and a vacuum chamber in communication with said last pillar or pillars.

11. In a vacuum cleaning apparatus, the combination of a supporting base, a pump therein, a diaphragm for said pump, an inletvalve in said pump and separating the same into a pair of compartments and seating by gravity, hollow supporting pillars carried by said base and forming air passages, a pump supported by said pillars and having a diaphragm, an exhaust valve connected with said pump and seating by gravity, some of said pillars connecting the upper compartment of the lower pump and the upper pump and some of said pillars communicating with the lower compartment of said lower pump, a vacuum chamber in communication with said last pillar or pillars, and a motor located between said pumps and operating the diaphragms thereof in unison simultaneously to draw in or expel air.

12. In a vacuum cleaning apparatus, the combination of a supporting base, a pump therein, a diaphragm for said pump, an inlet valve in said pump and separating the same into a pair of compartments and seating by gravity, hollow supporting pillars carried by said base and forming air passages, a pump supported by said pillars and having a diaphragm, an exhaust valve connected with said pump and seating by gravity, one or more of said pillars connecting the upper compartment of the lower pump and the upper pump and one or more of said pillars communicating with the lower compart'ment of said lower pump, a vacuum chamber in communication with said last pillar or pillars, a motor located between said pumps and operating the diaphragms thereof in unison simultaneously to draw in or expel air, and a casing surrounding said pump and motor mechanism and into which the exhaust air is expelled.

13. In a vacuum cleaning apparatus, the combination of a supporting base, a pump therein, a diaphragm for said pump, an inlet valve in said pump and separating the same into a pair of compartments and seating by gravity, hollow supporting pillars carried by said base and forming air passages, a pump supported by said pillars and having a diaphragm, an exhaust valve connected with said pump and seating by gravity, one or more of said pillars connecting the upper compartment of the lower pump and the upper pump and one or more of said pillars communicating with the lower compartment of said lower pump, a vacuum chamber in communication with said last pillar or pillars, a motor located between said pumps and operating the diaphragms thereof in unison simultaneously to draw in or expel air, and a casing surrounding said pump and motor mechanism and into which the exhaust air is expelled, said casing having a separating partition dividing said vacuum chamber from the pumping mechanism.

14. In a vacuum cleaning apparatus, the combination ofa vacuum chamber, pumping mechanism comprising a pair of pump chambers spaced apart and a diaphragm in each of said chambers, a motor located between said pumps and connected to the diaphragms for operating the same in unison simultaneously to draw in or expel air, a valve carried by each of said chambers one comprising an inlet valve and the other an exhaust valve and one of said valves dividing one of said chambers into a pair of compartments, one or more tubes in communication with the vacuum chamber and with one of said compartments, and tubes connecting the other of said compartments of the same pump chamber with the other of said pump chambers.

15. In a vacuum cleaning apparatus the combination of a vacuum chamber, an exhaust chamber, pumping mechanism com prising a pair of pump chambers spaced apart and located within the exhaust chamber and a diaphragm in each of said chambers, a motor located between said pumps and also located within the exhaust chamber and connected to the diaphragms for operating the samein unison simultaneously to draw in or expel air, a valve carried by each of said chambers one comprising an inlet valve and the other an exhaust valve and one of said valves dividing one of said oh ambers into a pair of compartments, one or more tubes in communication with the vacuum chamber and with one of said compartments, and tubes connecting the other of said compartments of the same pump chamber with the other of said pump chambers, each of said valves seating by gravity.

16. In a vacuum cleaning apparatus, the combination of a vacuum chamber, pumping mechanism comprising a pair of pump chambers spaced apart and a diaphragm in each of said chambers, a motor located between said pumps and connected to the diaphragms for operating the same in unison simultaneously to draw in or expel air, a valve carried by each of said chambers one comprising an inlet valve and the other an exhaust valve and one of said valves dividing one of said chambers into a pair of compartments, one or more tubes in communication with the vacuum chamber and with one of said compartments, tubes connecting the other of said compartments of the same pump chamber with the other of said pump chambers, each of said valves seating .by gravity, and a casing inclosing said pumping mechanism and into which the air is exhausted.

17. In a vacuum cleaning apparatus, the combination of a vacuum chamber, pumping mechanism comprising a pair of pump cham bers spaced apart and a diaphragm in each of said chambers, a motor located between said pumps and connected. to the diaphragms for operating the same in unison simultaneously to draw in or expel air, a valve carried by each of said chambers one comprising an inlet valve and the other an exhaust valve and one of said valves dividing one of said chambers into a pair of compartments, one or more tubes in communication with the vacuum chamber and with one of said compartments, tubes connecting the other of said compartments of the same pump chamber with the other of said pump chambers, each of said valves seating by gravity, and a casing inclosing said pumping mechanism and into which the air is exhausted, said casing also inclosing the vacuum chamber and having a partition separating the same from the air exhaust chamber thereof.

18. In a vacuum cleaning apparatus, the combination of a casing having a partition separating the same into a vacuum chamber and an exhaust chamber, a pair of diaphragm pumps spaced apart and located in said exhaust chamber, a motor located between said pumps for driving the same in unison simultaneously to draw in or expel air, a valve connected with each of said pumps and seating by gravity, one of said valves separating one of the pumps into a pair of compartments, an air inlet passage communicating with the vacuum chamber and with one of said compartments, and an air outlet passage communicating with the other compartment of the pump and with the other pump.

19. In a vacuum cleaning apparatus, the combination of a casing having a partition separating the same into a vacuum chamber and an exhaust chamber, a pair of diaphragrm pumps spaced apart and located in said exhaust chamber, a motor located between said pumps for driving the same in unison simultaneously to draw in or expel air, a valve connected with each of said pumps and seating by gravity, one of said valves separating one of the pumps into a pair of compartments, an air inlet passage communicating with the vacuum chamber and with one of said compartments, and an air outlet passage communicating with the other compartment of the pump and with the other pump, said passages consisting of pillars for supporting one pump above the other.

20. In a vacuum cleaning apparatus, the combination of a pair of diaphragm pumps spaced apart, a motor located between said pumps and connected with the diaphragms thereof and operating the same in unison simultaneously to draw in or expel air, valve mechanism connected with each of said pumps and comprising a member having one or more openings therein, an annular valve located in position to control said openings and seating by gravity, one of said valve mechanisms dividing one of said pumps into a pair of compartments, a vacuum chamber in communication with one of said compartments, and the other of said compartments being in communication with the other of said pumps.

21. In a vacuum cleaning apparatus, the combination of a pair of diaphragm pumps spaced apart, a motor located between said pumps and connected with the 'lia )hragms thereof and operating the same in unison simultaneously to draw in or expel air, valve mechanism connected with each oi. said pumps and comprising a member having one or more openings therein, an annular valve located in position to control said openings and seating by gravity, one of said valve mechanisms dividing one of said pumps into a pair of compartments, and a vacuum chamber in communication with one of said compartments, the other of said compartments being in communication with the other of said pumps, said communications being formed by hollow pillars constituting means for supporting one pump spaced apart from the other.

22. In a vacuum cleaning apparatus, the combination of a pair of diaphragm pumps spaced apart, a motor located between said pumps and connected with the diaphragms thereof and operating the same in unison simultaneously to draw in or expel air, valve mechanism connected with each of said pumps and comprising a member having one or more openings therein, an annular 'alve located in position to control said openings and seating by gravity, one of said valve mechanisms dividing one of said pumpsinto a pair of compartments, and a vacuum chamber in communication with one of said compartlnents, the other 01 said compartments being in communication with the other of said pumps, said communieations being formed by hollow pillars constituting means for supporting one pump spaced apart from the other, and means for clamping said pumps in position,

23. In a vacuum cleaning apparatus, the combination of a pair of diaphragm pumps spaced apart, a motor located between said pumps and connected with the diaphragms thereof and operating the same in unison simultaneously to draw in or expel air, valve mechanism connected with each of said pumps and comprising a member having one or more openings therein, an annular valve located in position to control said openings and seating by g'avity, one of said valve mechanisms dividing one of said pumps into a pair of compartments, a vacuum chamber in comnmnication with one of said compartments, the other of said compartments being in con'imunication with the other of said pumps, and a casing surrounding said pumping mechanism and having an outlet.

24. In a vacuum cleaning apparatus, the combination of a pair of diaphragm pumps spaced apart, a motor located between said pumps and connected with the diaphragms thereof and operating the same in unison simultaneously to draw in or expel air, valve mechanism connected with eaclr of said pumps and comprising a member liaving one or more openings therein, an annular valve located in position to control said openings and seating by gravity, one of said valve mechanisms dividing one of said pumps into a pair of compartments, a vacuum chamber in communication with one of said compartments, the other of said compartments being in communication with the other of said pumps, and a casing surrounding said pumping mechanism and having an outlet, said casing having a partition separating the vacuum chamber from the chamber in which the pumping mechanism is located.

25. In a vacuum cleaning apparatus, the combination of a pair of diaphragm pumps spaced apart, a motor located between said pumps and connected with said diaphragms for operating the same in unison simultaneously to draw in or expel air, a valve connected with each of said pumps, one of said valves separating one of said pumps into a ,pair of compartments, and a vacuum cham ber having a pair of oppositely disposed air passages in communication with one of said compartments and the other of said compartments having communication by a plurality of air passages with the other of said pumps.

26. In a vacuum cleaning apparatus, the combination of a pair of diaphragm pumps spaced apart, a motor located between said pumps and connected with said diaphragms for operating the same in unison simultaneously to draw in or expel air, a valve connected with each of said pumps, one of said valves separating one of said pumps into a pair of compartments, and a vacuum chamber having a pair of oppositely disposed air passages in communication with one 01 said compartments and the other of said compartments having communication by a plurality of air passages with the other of said pumps, said air passages being formed by tubes supporting one pump upon the other, and a casing inclosing said mechanism and separable from said tubes.

27. In a vacuum cleaning apparatus, the combination of a pair of diaphragm pumps spaced apart, a motor located between said pumps and connected with the diaphragms thereof for operating the same in unison simultaneously to draw in or expel air, a valve connected with each of said pumps, one of said valves separating one of said pumps into a pair of compartments, and a vacuum chamber having a pair of oppositely disposed air passages in communication with one of said compartments and the other of said compartments having communication by a plurality of air passages with the other of said pumps, said air passages being formed by tubes supporting one pump above the other and said valves seating by gravity.

28. In a vacuum cleaning apparatus, the combination of a pair of diaphragm pumps spaced apart, a motor located between said pumps and connected with the diaphragms thereof for operating the same in unison simultaneously to draw in or expel air, a valve connected with each of said pumps, one of said valves separating one of said pumps into a pair of compartments, a vacuum chamber having a pair of oppositely disposed air passages in communication with one of said compartments and the other of said compartments having communication by a plurality of air passages with the other of said pumps, said air passages being formed by tubes supporting one pump above the other and said valves seating by gravity, and a casing surrounding said pumping mechanism and having a chamber separated from said pumping mechanism.

29. In a vacuum cleaning apparatus, the combination of a vacuum chamber, pumping mechanism connected therewith and comp rising a pair of pump chambers spaced apart and each having a diaphragm, driving mechanism for operating said diaphragms in unison thereby simultaneously to draw in or expel air, an exhaust valve connected with one of said pumps, an inlet valve connected with the other of said pumps and dividing the same into a pair of compartments, one of said compartments having communication with the vacuum chamber and the other of said compartments having communica tion with the other pump.

30. In a vacuum cleaning apparatus, the combination of a vacuum chamber, pumping mechanism connected therewith and comprising a pair of pump chambers spaced apart and each having a diaphragm, driving mechanism for operating said diaphragms in unison thereby simultaneously to draw in or expel air, an exhaust valve connected with one of said pumps, and an inlet valve connected with the other of said pumps and dividing the same into a pair of compartments, one of said compartments having communication with the vacuum chamber and the other of said compartments having communication with the other pump, said valves seating by gravity, the organization being such that air from the vacuum chamber will be drawn through one of said compartments into the other of said compartments and from thence expelled through the other of said pumps.

31. In a vacuum cleaning apparatus, the combination of a vacuum chamber, pumping mechanism connected therewith and comprising a pair of pumps, means for driving said pumps in unison thereby simultaneously to draw in or expel air, a valve for each of said pumps one separating one of said Signed at Bloomington, 111., this 4th day pumps into a pair of compartments, the of March, 1911.

organization being such that air will be drawn into one of the compartments of said WVILLIAM RAKESTRAW' pump and from thence into the other com- \Vitnesses:

partment thereof and will then be expelled I-IUBERT D. BATH,

therefrom through the other pump. E. J. DONNELLY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

Corrections in Letters Patent No. 1,020,310.

It is hereby certified that in Letters Patent No. 1,020,310, granted March 12, 1912, upon the application of William H. Rakestraw, of Bloomington, Illinois, for an improvement in Vacuum-Cleaners, errors appear in the printed specification requiring correction as follows: Page 2, line -16, for the worc constitutes read constitute; page 3, line 7, before the word suitable insert the article a; page 1, lines 88-90, strike out the words In an exhaust chamber a vacuum cleaning apparatus, the combination of a vacuum and insert the words Ina vacuum cleaning apparatus, the combination of a vacuum chamber, an emhaast, page 7, line 37, for the syllable phragrm read p/arag m, and same page, line 102, for the word c0111- cation, and that the said Letters Patent should be read umnication read comniuni with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 2nd day of April, A. D., 1912.

o. o. BILLlNGS,

Acting Commissioner of Patents.

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