US2343732A

US2343732A - Vacuum cleaning apparatus

Info

Publication number: US2343732A
Application number: US413287A
Authority: US
Inventors: Douglas O Baird
Original assignee: RICHARD D MASON
Current assignee: RICHARD D MASON
Priority date: 1941-10-02
Filing date: 1941-10-02
Publication date: 1944-03-07
Anticipated expiration: 1961-03-07

Description

March 7, 1944. 0.. o. BAIRD I VACUUM CLEANING APPARATUS 2 Sheets-Sheet 1 Filed Oct. 2, 1941 INVOR Douglas O'Bczird BY 1oz M M Aiforneys March 7, 1944. 13 o. 'BAIRD' VACUUM CLEANING-APPARATUS 2 Sheets-Sheet 2 Filed 001:. 2. 1941 1 INVENTOR.

- INSULATION 73 mmza: 7

Patented Mar. 7, 1944 VACUUM CLEANING APPARATUS Douglas 0.

Baird, Evansion, 111., asslmor to chard D. Mason, Wilmette, ill. Application October z, 1941. Serial No. 413,287

Claims.

The present invention relates to improvements in vacuum cleaning apparatus and. more particularly, to improvements in vacuum cleaners of the household type conventionally used for cleaning rugs and other household articles. Specifically, the present invention relates to further improvements in a vacuum cleaner of the improved form disclosed and claimed'in copending application Serial No. 389,287, filed April 19, 1941, by Richard D. Mason and issued July 6, 1943, as Patent 2,323,554.

A cleaner of the general type mentioned conventionally includes a nozzle adapted. for movement relative to a surfac to be cleaned and a motor driven fan for creating a suction within the nozzle which serves to pull dust, dirt and other foreign matter from the surface being cleaned and to convey the same to a removable collecting bag. In the usual cleaner there is also provided agitating means in the form of a brush or heater, mounted within the nozzle of the cleaner, for beating the surface of the article being cleaned, thereby to facilitate the removal of dirt therefrom by the air stream created by the suction fan. If, as is frequently the case, the cleaner is, While operating, left standing for a considerable period of time on a surface being cleaned, the action of the air stream, the agitating means, or both, will damage the portion of the surface which is exposed to the action of the cleaner. Moreover, the usua household cleaner is always equipped with a manually operable switch for controlling the fan motor. Frequently, however, the operator prefers to pull the cord plug from the commercial current outlet box in use, in order to stop the cleaner, thus leaving the motor switch in its closed circuit position. When, thereafter, the cord plug is inserted in a live outlet, the fan motor immediately restarts with a resulting annoyance to the operator.

It is an object of the present invention, therefore, to provide improved vacuum cleaning apparatus of the general form briefly described above, in which the control of the cleaning action is fully automatic.

It is another object of the invention to provide an improved cleaner of the character described, wherein the 'starting'cf the cleaner is I accomplished in a fully automatic manner Without resort to manual switch operations.

It is a further object of the invention to provide an arrangement of the character described, which permits the movement of the cleaner over the surface being cleaned to be stopped for short intervals, during which it may be moved from place to place or furniture may be moved, without arresting the operation of the cleaner.v

It is still another object of the invention to provide an arrangement of the character described, wherein the operation of the cleaner may be automatically restarted immediately after the o eration thereof is automatically stopped.

It is another and more specific object of the invention to provide apparatus of simple,-,' 'economical and compact construction for automatically starting and stopping the cleaning action and for preventing the operation of the suction creating means, agitating means, or both, for more than a predetermined time interval after the cleaner has been left standing in one position.

In brief, the objects as set forth above are realized in accordance with the present invention by providing vacuum cleaning apparatus of the form briefly described, which includes means controlled by the relative movement between the suction nozzle and a surface being cleaned for automatically starting and stopping the operation of the suction creating means and, if provided or desired, the agitating means. In the illustrated embodiment of the invention, a roller actuated switch and a combined circuit controllerand timing device are provided, which elements cooperate automatically to close the operating circuit for th driving motor of the cleaner each time movement of the cleaner over the surface to be cleaned is started, and automatically to interrupt the motor operating circuit a predetermined time interval after movement of the nozzle over the surface undergoing cleaning is arrested The time interval as measured by the timing device permits the cleaner to be stopped for short intervals without any pause in the operation thereof.

The invention, both as to its organization and method .of operation, together with further objects and advantages thereof, will best be understood by reference to the specification taken in connection with the accompanyi drawings in which Fig. 1 isa view, partially in section, illustrating a vacuum cleaner of the form briefly described above. having the features of the present invention embodied therein; Figs. 2, 3,v 4 and 5 illustrate the details of the roller actuated switch forming a part of the cleaner shown in Figs. 1; Fig. 6 illustrates the details of the combined circuit controller and timing device embodied in the cleaner; and Fig. 7 illustrates the control circuit for the cleaner.

Referring now more particularly to Fig. l of the drawings, the vacuum cleaner there illustrated comprises a suction nozzle in the form of a lower housing member ID having along its bottom portion a suction orifice ll through which dust. dirt or other foreign matter extracted by the air stream from the rug 9 is conducted to a removable dust collecting bag l2. The housing member I is provided with a rearwardly extending pocket 1 in the nose thereof. A socket for receiving a lamp bulb 8 is mounted within this pocket in any desired manner. The lamp is arranged to be energized when the cleaner is in use and serves to illuminate the surface being cleaned. For the purpose of creating a suction within the nozzle In there is provided means comprising a fan l3 carried by the driving shaft. ll of an electric motor I5, which motor is enclosed by a housing member 15a in the manner illustrated. The member I5a. is flanged along its lower edge and rests in an enlarged opening'provided in the upper portion of the housing member I0 to provide an airtight joint between the two members.

More specifically, the fan 13 is arranged to rotate in a partially enclosed space formed by the bottom portion of the motor housing and the downwardly projecting inturned portion iii of the member I0. Projectin through the open bottom portion of the portion I6 of the member I0 is a pulley H which is mounted for rotation with the motor shaft H. A brush i8 is provided which is mounted for rotation within the housing member I0 in any desired manner, and is arranged to be driven from the motor l5 by an endless belt [9 which extends between the pulley I1 and a similar pulley provided on the shaft of the brush. This brush or agitator is provided with bristles around its peripheral surface, which are arranged to extend through the orifice H to contact the surface being cleaned, thereby to loosen dirt embedded in the surface so that it may easily be removed by the air stream. The cleaner is supported on rollers 20 and 2| carried by, the housing member l0 and 'is adapted to be moved over a rug, or the like, by a handle 22.-

This handle is provided with a bail which is pivotally mounted at its extremities on the sides of the housing member In.

Referring now to Figs. 2, 3, 4, 5, 6 and 7 of the drawings, there is illustrated the electric circuit apparatus for controlling the driving motor l5. In general, this apparatus comprises a combined circuit controller or relay and timing device 23, and a roller actuated switch 24. These elements cooperate to control the energization of the motor 4 I5 from the source of current indicated at 26, current being conducted from this source to the motor over the

cord conductors

21 and 28. More specifically considered, the device 23 comprises an alternating current relay 60 which comprises a magnetic field structure 6| of conventional arrangement, an operating winding 52, a holding winding 63 and a pivoted armature 64 which is provided with an arm 65 for controlling the contact springs 66, 61 and 68 of a suitable spring pile. The enumerated contact springs are mounted on a bracket piece 10 which extends outwardly from the magnetic field structure 6i, and are insulated'from the field structure and from each other by means of the insulating pieces II.

The timing element of the device 23 comprises a bi-metal strip 12 having its base end fixedly mounted upon an insulating block 13 which is pivotally mounted at 14 between two arms 15 which extend vertically from the bracket piece a contact 16 which is adapted to be moved away from an associated stationary contact 11 when the strip is flexed under the influence of heat produced by a heating element 18. This heating element may be in the form of resistance wire wound around a mica strip 19 which is mounted on two insulating pillars carried by the bracket piece HI. The stationary contact 11 is in the form of an adjustable screw which is threaded through the outer end of the bracket piece 'll to permit ready adjustment thereof relative to the movable contact 16. As shown in the drawings, the insulating block 13 is provided with a laterally extending V-shaped notch 13a which receives the outer knife-edged end of the armature 64. Thus, the position of the free end of the bi-metal strip I2 is in part determined by the position of the armature 64 and in part by the influence of the heating element 18. With the armature 64 restrained in its restored position under the influence of the contact spring 58 and the additional biasing spring 8|, the contacts 16 and TI are disengaged.

The control of the device 23 is effected by the roller actuated centrifugal switch 24, the details of which are best shown in Figs. 2, 3, 4 and 5 of the drawings. Briefly described, this switch comprises a pair of normally disengaged

contact springs

29 and 30 which are biased to move into engagement and a pair of

contact springs

34 and 35 which are biased to move out of engagement when released by the friction plate 36 of a fly to a collar 39 which carries the friction plate 36.

This collar is free to slide along a drive shaft 4|, which is arranged to be driven by the rollers 20a and 20b. The left ends of the two leaf springs are anchored to a second collar 40 which is mounted for rotation with the drive shaft 4| by means of a set screw 40a. This drive shaft is journaled in

bearing brackets

45 and 46 which are mounted upon the switch base 24a by means of screws 41 and 48. The under side of the base 24a also carries the

contact springs

34 and 35 which are insulated from each other and from the base by suitable insulating means included in the mounting assembly 49. The two leaf springs 31 and 38

carry fly balls

42 and 43, respectively, which are thrown outward by centrifugal force when the shaft 4| is rotated, and serve to slide the collar 39 along the shaft 4| toward the collar 40 to permit separation of the

contact springs

34 and 35 accompanied by engagement of the

contact springs

29 and 30.

The two ratchet and gear mechanisms 44 and 45 are arranged to impart continuous rotation to the shaft ll in the same direction as the cleaner is moved forward and backward over the, surface being cleaned. More specifically, the roller 20b, in cooperation with the mechanism 45, is arranged to rotate the shaft 4| in a counter-clockwise direction as viewed from the left end of Fig. 2 when the cleaner is moved forward. The roller 20a, in cooperation with the mechanism 44, is arranged to rotate the shaft 4! in the same direction when the cleaner is moved backward over the surface being cleaned. Briefly described, the drive connection 44 comprises a pawl a carried by the roller 20a and spring biased to engage the teeth of a ratchet wheel b which is mounted for rotation with a gear 0. This gear meshes with a second spur gear Md mounted on the left end of the shaft 4|. The drive connection 45 similarly comprises a pawl 45a carried by the roller 20b and spring biased to engage the teeth of a ratchet wheel 45b which is mounted for rotation with a gear 45c. This gear is arranged to drive a gear 45d mounted upon the right end of the drive shaft 4| through an idler gear 45a. The

gears

44c and 45c are of the same size and have the same number of teeth. Similarly, the

gears

44d, 45d and 65e are of the same size and have the same number of teeth. The mountin assembly for the enumerated gears and rollers includes a shaft 50 which extends between and is secured at its ends to the downwardly extending

end portions

24b and 240 of the base 24a. The rollers 20a and 20b, the ratchet Wheels 44b and 45b, and the gears 44c and 450 are all rotatably mounted on the shaft 50,

Collars

50a and 50b are mounted upon the shaft 50 to restrain the

gears

44c and 45c against lateral movement. The idler gears 45c is mounted-upon a shaft which is joumaled in the bearing bracket 46 and a third bearing bracket 52, also mounted on the underside of the base 24a.

In its normal use, the plug end of the cleaner is inserted in a commercial current outlet and the cleaner is then moved forward and backward across the surface being cleaned. Incident to such movement, and irrespective of its direction, the roller actuated switch 24 functions to disengage the contact springs 34 and 35, and to move the contact springs 29 and 30 into engagement. Thus, as the cleaner i moved forward across a surface being cleaned, such, for

example. as the rug 9, rotary movement is imparted to the shaft 4| by the roller 2012 through the drive connection 45. More specifically, the pawl 45a engages one of the teeth of the ratchet wheel 45b to lock the roller 20b and the gear 450 against relative movement, immediately clockwise rotation of the rollers 20a and 20b,as viewed from the right end of\ Fig. 2, is started. As the gear 450 continues to rotate with the roller 20b. clockwise rotation is imparted to the drive shaft 4| through this gear, the idler gear 45c and the drive gear 45d. Preferably, a relatively high gear ratio between the gear 450 and the

gears

45d and 45e is employed, so that the speed of rotation of the drive shaft 4| is considerably above 1 that of the roller 20b. As the shaft 4| rotates,

the

balls

42 and 43 are thrown outward by centrifugal force to draw the colla1-39 and friction plate 35 away from the contact spring pile toward the collar 40. In response to this movement of the friction plate 36, the contact springs 34 and 35 are disengaged and the contact springs 29 and 30 are moved into engagement.

The rotation of the shaft 4| is also imparted to the gear 44c and the ratchet wheel 44b through the drive gear 44d, but the direction of rotation of this ratchet wheel is such that the pawl 44a rides over the teeth thereof. Thus, the mechanism is not locked against operation, due to the relative movement between the ratchet wheel 44b and its associated driving roller 20a, during forward movement of the cleaner.

Each time the cleaner is moved in the reverse direction, 1. e., backward. the rotation of the shaft 4| in the same direction is continued through the driving connection 44 between this shaft and the roller 20a. Thus, each time counter-clockwise rotation of the roller 20b is started. as viewed from the right end of Fig. 2, the pawl 44a engages one of the teeth of the ratchet wheel 44b to lock the roller 20a and the gear 44c against relative rotation. The gear 440 meshing with the drive gear 44d serves to continue the clock'-. wise rotation of the shaft 4|. During the con tinued rotation of this shaft, the gear 450 and the ratchet wheel 45b continue to be driven in a clockwise direction through the

gears

45d and 45e. The roller b is at this time revolving in a counter-clockwise direction. During such relative movement between the gear 450 and the roller 20b the pawl 45a rides over the teeth of the ratchet Wheel 4512 and, accordingly, the mechanism isnot locked a ainst operation.

Each time the direction of movement of the cleaner is changed, the rotation of the rollers 20a and 20b is momentarily arrested. During each such transition period, the mechanical inertia of the rotating system serves to continue the rotation of shaft 4| for an interval somewhat in excess of the period ordinarily required for a change in the direction of movement of the cleaner. Each time this occurs, both of the

pawls

44a and 45a ride over the teeth of their respective associated ratchet wheels 44b and 45b. In other words, the ratchet wheels over-run their respective associated pawls to permit the continued free rotation of the shaft 4i. It will be understood from the above explanation that the contact springs 34 and 35 are held out of engagement and the contact springs 29 and are held in engagement during the short intervals when the movement of the cleaner' over the rug is stopped in changing the direction of movement thereof.

When movement of the cleaner over the rug is started to initiate the operation of the switch 24 in the manner just explained, a circuit including the contact springs 66, 61, 29 and 30, and the

cord conductors

21 and 28 is completed for energizing the operating winding 62 of the control device 23. At the same time, the contact springs 34 and are disengaged to open a point in the incomplete circuit for energizing the heat- I ing element 18. When its operating winding 62 is thus energized, the device 23 attracts its armature 64. Incident to the movement of this armature, the contact springs 68 and 61 are first engaged, the bi-metal strip 12 is then rocked about its pivot point 14 to bring the

contacts

16 and 11 into engagement, and finally the contact springs and 61 are'disengaged. Atthe contacts I6 and I1, and the contact springs 68 and 61a circuit including the bimetal strip 12 is completed for energizing the holding. winding 63 of the device 23, thereby to maintain the armature 64 in' its attracted position after the operating winding 62 is deenergized. At the contact springs 61 and 68, the circuit for energizing the heating element 18 is also prepared. At these same contact springs, an obvious circuit is completed for energizing the motor i5 and the lamp 8 in parallel. Thus, the lamp 8 is energized to illuminate the area of the rug being cleaned, and operation of the motor l5 to drive the fan I3 and the brush i8 is initiated. Incident to the disengagement. of the contact springs 56 and 61', the circuit for energizing the operating winding 62 of the device 23 is broken, thereby to reduce the current drain on the supply source.

When movement of the cleaner over the rug is arrested, the shaft 4| continues to rotate for a short interval and then gradually slows to a stop. Incident to the final movement of the shaft the springs 31 and 38 pull the

balls

42 and 43 toward the shaft and slide the friction plate 36 to the right to open the contact springs 29 and 30, and

the bi-metal strip 12 to close the contact springs 34 and 35. At the contact springs 29 and 30, a second point is opened in the circuit for energizing the operating winding 62 of the device 23. when the

springs

34 and 35 are moved into engagement, a circuit including the engaged contact springs 61 and 68, and the

conductors

21 and 28, is completed for energizing the heater 18. Under the influence of the heat produced by the heater I8,

is flexed upward. Assuming that the movement of the cleaner is not restarted, the contact I8 is moved by the bi-metal strip I2 to disengage the contact 11 a predetermined time interval after the heater I8 is energized. When these contacts are opened, the holding winding 63 is obviously deenergized to permit the release of the armature 64 under the influence of the spring bias aiIorded by the contact spring 68 and the additional spring 8|. In returning to its normalposition, this armature closes its contact springs 68 and 81, opens its contact springs 61 and 68, and rocks the bimetal strip 12 further to separate the

contacts

16 and 11. At the contact springs 68 and 61, the circuit for energizing the motor I! and the lamp I in parallel, is interrupted. Thus, the operation of the motor I! to drive the fan l3 and the brush I8 is arrested a predetermined time interval after movement of the cleaner is stopped. At the contacts l5 and I1, and the contact springs 61 and 68, additional points are opened in the circuit for energizing the holding winding 63 of the device 23. At the contact springs 61 and 68, the circuit for energizing the heating element 18 is also opened.- At the contact springs 66 and 61, the circuit for energizing the operating winding 62 of the device 23 is reprepared. Thus, the control circuit is fully restored to normal.

Immediately the heater 18 is deenergized, the iii-metal strip 12 starts to cool so that only a few seconds after the operation of the motor I5 is automatically arrested in the manner just explained, the cleaner may be restarted to cause thereoperation of the control device 23. In this regard it will be apparent that if the operation of the machine is restarted shortly after its operation is automatically arrested, the cooling of the bi-metal strip 12 will continue as the cleaner is moved over the rug. Thus, the roller actuated switch 24 functions to hold the circuit for' energizing the heater 18 open so long as the cleaner is being used. It will also be understood that if movement of the cleaner is restarted during a timing period when the heater I8 is energized, the switch 24 functions to deenergize the heater so that the bi-metal strip may be flexed back to its normal shape during the continued use of the cleaner. Thus, provisions are made for preventing the false operation of the apparatus prov ded to automatically arrest the operation of the cleaning facilities and for insuring a measured time interval of substantially fixed duration.

From the above explanation it will be apparent that the length of each timing interval may be changed at will by adjusting the stationary contact 11 relative to the movable contact 16. It will also be understood that when the bi-metal strip 12 is flexed to separate the contacts 16 and I1 slightly at the end of a timing period, the arma-' ture 84 is immediately released to produce further separation 01 these contacts. Thus, the device 23 is substantially "trip free" in that the initial separation of the contacts 18 and I1 is augmented hv izl-w immnfliah: melon-w nf the arrrmmember ID,

ture 64. Moreover, the release of the armature 64 to rock the bi-metal strip 12 out of the heating zone of the heating element 18, serves to lessen theeffect of the residual heat stored in this element on the strip. Accordingly, the initial return flexure of the bi-metal strip to a shape wherein the

contacts

76 and 11 may be moved into engagement under the control of the armature 64, is rapidly completed. If desired, provisions may be made in the circuit shown in Fig. 7 of the drawings for selectively rendering inactive the automatic control facilities described above. In such case the manually operable switch may be provided. This switch, which includes the contact springs 86 to 90, inclusive, and the operating member 9!, may be mounted upon the housing and may be used for maintaining the motor l5 continuously in operation. In certain instances where the cleaner is to be used in conjunction with different types of cleaning attachments, this is desirable. In order to incorporate the switch in the control circuit, the contact spring 86 is connected to the terminal 92; the connection between the terminals 93 and 94 is omitted and these terminals are respectively connected to the contact springs 81 and 88; and the connection between the

terminals

95 and 95 is opened and these terminals are respectively con-- nected to the contact springs 89 and 90.

With the circuit modified in the manner just explained and the switch 85 occupying its illustrated normal position, the automatic control facilities are operative in the exact manner described above. As modified, however, the operating and locking circuits for the control device 23 and the circuit for energizing the heating element 18 commonly include the contact springs 81 and 88 instead of the connection between the terminals 93 and 94. The locking circuit for the device 23 also includes the contact springs 89 and instead of the connection between the terminals and 96.

When the operating member 9| of the switch 85 is depressed, the contact spring 81 is moved out of engagement with the spring 88 and into engagement with the contact spring 86, and the contact springs 89 and 90 are disengaged. At the contact springs 81, 88, 89 and 90 the circuits for energizing theheating element 18 and the operating and locking windings of the control device 23 are all opened. Thus, the automatic control facilities are rendered inactive. At the contact springs 86 and 81, an obvious circuit is completed for energizing the motor l5 and the lamp 8 in parallel, thereby to initiate the operation'of the cleaning means. when the switch 85 is manually restored to normal, at which time the automatic control facilities are again conditioned fo operation.

While one embodiment of the invention has been described, it will be understood that various modifications-may be made therein, without departing from the true spirit and scope of the invention.

What is claimed is:

1. In a vacuum cleaner, a nozzle adapted to be moved over a surface to be cleaned, means for producing a cleaning action in the area of said surface which registers with the opening of said nozzle, an electric motor for driving said cleaning means, electric circuit means operative in response to movement of said nozzle over said surface for automatically rendering said motor operative to drive said cleaning means, and means This circuit is only opened crating so long as said cleaner is standing at rest on said surface.

8. In a vacuum cleaner, a nozzle adapted to be moved over a surface to be cleaned, means for producing a. cleaning action in the area of said surface which registers with the opening of said nozzle, an electric motor for driving said cleaning means, a circuit for energizing said motor, means for holding said circuit open so long as said cleaner is standing at rest on said surface; and circuit control means operative only in response to movement of said nozzle over said surface for completing said circuit,

3. Vacuum cleaning apparatus comprising, in combination, a nozzle adapted for movement over a surface to be cleaned, means for creating asuction within said nozzle, an electric motor for driving said suction creating means, electric circuit means for rendering said motor operative to drive said suction creating means, means for preventing said electric circuit means from operating so long as said apparatus is standing at rest on said surface. and means responsive to movement of said nozzle over said surface for effecting operation of said electric circuit means thereby to ren der said motor operative to drive said suction creating means.

4. Vacuum cleaning apparatus comprising, in combination, a. nozzle adapted for movement over a surface to be cleaned, agitating means mounted within said nozzle, an electric motor for driving said agitating means, electric circuit means for rendering said motor operative to drive said agitating means, means for preventing said electric circuit means from operating so long as said apparatus is standing at rest on said surface, and means responsive to movement of said nozzle over said surface for effecting operation of said electric circuit means, thereby to render said motor operative to drive said agitating means.

5. Vacuum cleaning apparatus comprising, in combination, a nozzle adapted for movement over a surface to be cleaned, agitating means mounted within said nozzle, means for creating a suction within said nozzle, an electric motor for driving said agitating means and said suction creating means, electric circuit means for rendering said motor operative to drive said agitating means and said suction creating means, means for preventing said electric circuit means from operating so long as said apparatus is standing at rest on said suriace, and means responsive to movement of said nozzle over said surface for effecting operation of said electric circuit means, thereby to render said motor operative to drive said agitating means and said suction creating means.

6. In a vacuum cleaner, a nozzle adapted to be moved over a surface to be cleaned, means for producing a cleaning action in the area of said surface which registers with the opening of said nozzle, an electric motor for driving said cleaning means, a normally open circuit for energizing said motor, a relay operative to complete said circuit, means responsive to movement of said nozzle over said surface for energizing said relay, and a locking circuit for said relay, said locking circuit being completed in response to operation of said relay.

7. In combination with a vacuum cleaner which is movable over a surface to be cleaned and includes cleaning means and an electric motor for driving said cleaning means, electric circuit means operative in response to movement of said cleanor over said surface for automatically rendering said motor operative to drive said cleaning means,

iii

and electric circuit means for automatically arresting the operation of said cleaning means when movement of said cleaner over said surface is arrested. I

8. In combination with a vacuum cleaner which is movable over a surface to be cleaned and includes cleaning means and an electric motor for driving said cleaning means, a normally open circuit for energizing said motor, means for automatically closing said circuit'when movement of said cleaner over said surface is started, means for automatically opening said circuit when movement of said cleaner over said surface is arrested,

and means for preventing said last named means from operating during the momentary stoppage of said cleaner which occurs at the end of each stroke of the cleaner over said surface.

9. In combination with a vacuum cleaner which includes means for exerting a cleaning action on a surface to be cleaned and an electric motor for driving said cleaning-means, means for automatically conditioning said motor to drive said cleaning means when movement of said cleaner over said surface is started, a timing device, means for conditioning said timing device to measure a predetermined time interval when movement of said cleaner over said surface is arrested, and means conitrolled by said device for arresting the operation of said cleaning means at the end of-the measured time interval.

ill. in combination with a vacuum cleaner which includes means for exerting a. cleaning action on a surface to be cleaned and an electric motor for driving said cleaning means, means for automatically conditioning said motor to drive said cleaning means when movement of said cleaner over said surface is started, and means including a time delay device for automatically arresting the operation of said cleaning means a predetermined time interval after movement of said cleaner over said-surface is arrested.

ii. A vacuum cleaner comprising means for exerting a cleaning action on a surface to be cleaned, an electric motor for driving said cleaning means, a normally open circuit for energizing said motor, means :for automatically closing said circuit when movement of said cleaner over said surface is started, and means including a time delay device for automatically opening said circuit a predetermined time interval after movement of said cleaner over said surface is arrested.

22. A vacuum cleaner comprisingmeans for exerting a cleaning action on a surface to be cleaned, an electric motor for driving said cleaning means, a normally open circuit for energizing said motor, a. centrifugal switch operative in response to movement of said cleaner over said surface, means controlled by said switch for automatically closing said circuit when movement of said cleaner over said surface is started, and means including a time delay device controlled by said switch for opening said circuit a predetermined time interval after movement of said cleaner over said surface is arrested.

13. A vacuum cleaner comprising means for exeating a cleaning action on a surface .to be cleaned, an electric motor for driving said cleanlug means, a normally open circuit for energizing said motor, a centrifugal switch operative in response to movement of said cleaner over said surface, and means controlled by said switch for automatically closing said circuit when movement of said cleaner over said surface is initiated and for automatically opening said circuit when movement of said cleaner over said surface is arrested.

14. A vacuum cleaner comprising means for exerting a cleaning action on a surface to be cleaned, an electric motor for driving said clean 15. A vacuum cleaner comprising means for exerting a cleaning action on a surface to be cleaned, an electric motor for driving said cleaning means, a normally open circuit for energizing said motor, a relay operative to complete said circuit, operating and locking circuits for said relay, means for automatically closing said operating circuit when movement of said cleaner over said surface is started, said relay being operative to complete its locking circuit and to then open its operating circuit, a timing device including a bimetal element, a heating element and contacts controlled by said bi-metal element for opening said locking circuit a predetermined time interval after said heating element is energized, a normally open circuit for energizing said heating element, and means for automatically closing said last-named circuit when movement of said cleaner over said surface is arrested.

16. A vacuum cleaner comprising means for exerting a cleaning action on a surface to be cleaned, an electric motor for driving said cleaning means, a normally open circuit for energizing said motor, a relay operative to complete said circuit, operating and locking circuits for said relay, said relay being operative to complete its locking circuit and to then open its operating circuit, a switch operative in response to movement of said cleaner over said surface, and means controlled by said switch for closing said operating circuit when movement of said cleaner over said surface is started and for opening said locking circuit when movement of said cleaner over said surface is arrested.

17. A vacuum cleaner comprising means for exerting a cleaning action on a surface to be cleaned, an electric motor for driving said cleaning means, an electric circuit adapted to be controlled to render said motor operative to drive said cleaning means, means responsive to movement of said cleaner over said surface for controlling said circuit to render said motor operative to drive said cleaning means, means for automatically controlling said circuit to render said motor inoperative to drive said cleaning means when movement of said cleaner over said surface is arrested, and means for preventing said lastnamed means from operating during the m'omentary stoppage of said cleaner which occurs at the end of each stroke of the cleaner over said surface.

18. A vacuum cleaner comprising means for exerting a cleaning action on a surface to be cleaned, an electric motor for driving said cleaning means, a normally open circuit for energizing said motor, a relay operative to complete said circuit, operating and locking circuits for said relay, means for automatically closing said operating circuit when movement of said cleaner over said surface is started, said relay being operative to complete its locking circuit and to then open its operating circuit, means for automatically opening said locking circuit when movement of said cleaner over said surface is arrested, and means for preventing said last-named means from operating during the momentary stoppage of said cleaner which occurs at the end of each stroke of the cleaner over said surface.

19. A vacuum cleaner comprising means for exerting a cleaning action on a surface to be cleaned, an electric motor for driving said cleaning means, a normally open circuit for energizing said motor, a relay operative to complete said circuit, operating and locking circuits for said relay, means for automatically closing said operating circuit when movement of said cleaner over said surface is started, said relay being operative to complete its locking circuit and to then open its operating circuit, and means including a time delay device for automatically opening said locking circuit a predetermined time interval after movement of said cleaner over said surface is arrested.

20. In a vacuum cleaner which includes an actuating handle, cleaning means and a motor for driving said cleaning means; the combination which includes electric circuit means operative automatically to render said motor operative to drive said cleaning means in response to manual actuation of said handle to move said cleaner over a surface to be cleaned, and means whereby said electric circuit means is prevented from operating so long as said cleaner is standing at rest on said surface.

DOUGLAS 0. BAIRD.