US2267765A - Suction cleaner - Google Patents

Description

Dec. 30, 1941. c. H. TAYLOR SUCTION CLEANER Filed May 9, 1938 2 Sheets-Sheet l Cfiarles H Taylor ATTORNEY Dec. 30, 1941. c. H. TAYLOR SUCTION CLEANER Filed May 9, 1938 2 Sheets-Sheet 2 INVENTOR ATTORNEY Patented Dec. 30, 1941 SUCTION CLEANER Charles H. Taylor, Springfield, Mass., assignor to The Hoover Company, North Canton, Ohio, a

corporation of Ohio Application May 9, 1938, Serial No. 206,740

6 Claims.

This invention relates to improvements in suction cleaners and more particularly to an arrangement whereby the suction nozzle of a cleaner is automatically maintained at the correct height with reference to the surface of the floor covering to be cleaned regardless of its quality, texture and characteristics.

In the design and manufacture of suction cleaners it has heretofore been the standard practice to provide some form of manually operated adjusting mechanism or device for adjusting the height of the nozzle for operation on different grades and thickness of carpet, it being well known that a uniform spacing of the nozzle above the carpet surface is essential to eflicient operation and effective cleaning and, that the nozzle should be raised or lowered to compensate for the varying depths to which the wheels of the cleaner must necessarily sink into the nap depending on the particular carpet being cleaned. To illustrate, carpets (which include all floor coverings) may be divided roughly into three classes; viz, thin, medium, and thick, to designate degrees in depth of the carpet nap as well as the texture and thickness of the fibers that form the pile of the carpet. Thus, the extremes in floor coverings might be linoleum (which is the equivalent of a bare floor surface) and a very thick chenille or velvet carpet, and intermediate these extremes are numerous kinds and grades of carpeting varying in degrees of depth of nap and fibre texture.

And as an aid in making adjustments in nozzle height for different kinds or makes of carpets, the more common types of manually operated adjusting devices are equipped with indicators which tell the operator whether the nozzle is set at the low, medium, or high position. But the recognized objection to the manual adjusting devices is the fact that the average user is not sufliciently familiar with operating conditions to make the proper adjustment and consequently when made, it is quite likely to be incorrect. Then again, the operator may neglect to make any adjustment so that the nozzle may be properly set for some carpets and improperly for others.

The object of the present invention is to eliminate the uncertain and haphazard aspects of nozzle height adjustment by incorporating into a suction cleaner, an arrangement of parts which will enable the same to adjust itself automatically to whatever kind or texture of carpet is to be cleaned and without the exercise of any effort,

In fact, the only physical act involved in completing the adjustment is the placing of the cleaner upon the carpet or other floor covering to be cleaned. And in this connection, the socalled full automatic type of nozzle height adjustment is here designated in order to distinguish it from another type of nozzle height adjusting mechanism which is partially or semiautomatic in its operation to the extent that it involves the depression and release of a foot pedal by the operator in order to initiate as well as complete the adjustment.

And finally, the object of the present invention is to provide a particular type of full automatic nozzle height adjusting means characterized rimarily by the use of pairs of front and rearwardly disposed wheels fixed against bodily adjustment and generally of standard dimensions, except that the front wheels are relatively wider, the term width" as herein used referring to the transverse dimension of the wheels surface or tread. And, a secondary characteristic of the type of nozzle adjusting mechanism herein disclosed is the association of vertically adjustable spring-actuated wheels with the fixed front supporting wheels acting to carry a part of the load.

With the foregoing introductory matter and preliminary explanation, the details of the invention will now be more fully disclosed in connection with the accompanying drawings in which:

Figure 1 is a general view in side elevationof a typical suction cleaner with a portion of the side wall of the casing broken away;

Figure 2 is a fragmentary bottom plan view of the cleaner body showing the mounting of one set of the adjusting wheels;

Figure 3 is a detail view in vertical section taken on line 3-3 of Figure 1;

Figure 4 is a view in side elevation corresponding to Figure 1 showing the adjustment under operating load conditions;

Figure 5 is a detail view in vertical section taken on line 5-5 of Figure 4;

Figure 6 is a view in side elevation of a suction cleaner equipped with a modified type of automatic nozzle adjustment; and

Figure 7 is a fragmentary bottom plan view of the modified type of adjustment shown in Figure 6.

The suction cleaner herein disclosed may be considered to be any standard handle-maneuvered type designed for household use and consisting generally of a wheel-supported casing I physical or mental, on the part of the operator. provided with a nozzle portion 2 extending transin a flanged connection 6a to which is detachably mounted a suction bag I. The fan chamber also has an inlet or fan "eye" 8 located in its bottom wall concentric with the axis of the fan and opening into a passageway extending forwardly and communicating with the nozzle portion of the cleaner and through which the dirt laden air enters the fan chamber, to be eventually discharged into the dirt bag I.

As clearly shown in Figure 1, the nozzle portion of the cleaner is a transverse elongated chamber open along its underside to form the downwardly facing suction mouth. The passage from the suction chamber to the fan chamber previously mentioned, is formed by a removable bottom plate 9 extending rearwardly from the nozzle chamber and including the space immediately below the fan eye."

Mounted within the nozzle and extending lengthwise thereof is a rotary agitator I having the form of a cylindric shell with a suitable arrangement of brushes I0a and beater-bars IIlb projecting from the surface thereof. The agitator, being well known in the suction cleaner art, need not be further described except to point out that it is driven by means of a belt II passing through the air passage from the nozzle chamber and extending from a pulley I2 forming an extension of the hub of the fan, to a pulley groove on the agitator II).

The cleaner casing is supported upon pairs of fixed front and rear wheels, the front wheels I3I3 being located within the recesses or cavities just rearwardly of the nozzle chamber and between the side walls 3, 3 and the fan chamber 6. These front wheels I3, I3 are supported in brackets I4, I4, fastened by means of screws to the underside of the top wall of the casing I and comprising a pair of depending arms Ha, Ha which straddle the wheels I3, I3 and support their journal pins I3a. The rear wheels I5, I preferablyrform a caster unit including a bracket -10 which is riveted to the underside of the cleaner casing immediately forward of the exhaust outlet. Thus both pairs of front and rear wheels I3 and I5 are journalled on bearings that are fixed with relation to the cleaner body and except for certain dimensional variations are similar in all respects to any standard fixed wheel arrangement.

An important feature to be noted in connection with the fixedly mounted front and rear wheels I3 and I5 is the fact that the former are somewhat wider than the latter. As shown in Figure 2, the front wheels are almost twice the width of the rear wheels which may be assumed to be of standard width, of say one-half /2) an inch.

, However, the relative widths of the front and rear wheels are not to be considered as definite or fixed but variable with the design and load conditions of a given cleaner, as will presently be explained.

To complete the general cleaner assembly, the usual handle arrangement is provided for maneuvering the cleaner overthe carpet surface. The

handle is not shown except for the U-shaped bail I I which straddles the motor hood 4 and has pivotal connection at its ends with brackets II mounted on the underside of the casing just inwardly from the front wheel mounting 3. Torsion springs I8 are preferably included in the handle mounting and act to hold the handle in its upright position as shown in Figure 1.

Now, associated with the front supporting wheels I3, I3 is a pair of auxiliary wheels III, 24 which are located immediately inwardly from and substantially in axial alignment with the fixed wheels. These auxiliary wheels are of the same diameter of the adjacent fixed wheels but somewhat narrower in width and preferably of the same width as the rear wheels I 5, I5. But here again, the relationship between the width of the auxiliary wheels 20, 2d and that of either the fixed front wheels or the rear wheels may vary.

The auxiliary wheels 20, 20 diifer essentially from the other wheels in that they are adjustable bodily and in a general vertical direction relative to the cleaner casing and to this end each is journalled at the outer end of a supporting lever 2| pivotally mounted to shift vertically through a small arc from a general horizontal position. Each lever 2I is a U-shaped member which straddles the wheels and carries a pin 2Ia on which each wheel is journalled. The rear end of each lever 2| is supported on a transverse bearing pin 22 carried in a forwardly opening U-shaped section 23, integral with the bracket I4 which supports and carries its associated front wheel I3. Each auxiliary wheel is thus capable of a limited rocking movement through a relatively small arc and in one direction against a torsion spring 24 coiled around the bearing pin 22, with one end bearing on the upper edge of lever 2| and the other end suitably anchored to the bracket I4. Each torsion spring .24 is under tension and exerts a constant pressure on the wheel carrying lever 2| in a counter-clockwise direction, that is to say, in a direction to force each auxiliary wheel 20 in a downward direction with its point of contact with the carpet surface slightly below that of the fixed front wheels I3. Moreover, the tension exerted by each torsion spring 24 bears a definite relationship to the static load normally supported by the front wheels when the cleaner is at rest and inoperative, viz, the pressure exerted by the springs 24, 24 to depress the auxiliary wheels 20, 20 is calculated at an amount slightly less than that necessary to overcome-or counterbalance the static load which otherwise would be carried by the front wheels. It follows then, that the auxiliary wheels, depressed under the tension of the springs, serve to relieve the fixed wheels I3, I3, of practically the entire static load under non-operating conditions. Moreover, these auxiliary wheels being relatively narrow tend to sink into or penetrate the carpet nap to a relatively greater depth than the wider fixed wheels I3, I3 and hence it can be assumed that the auxiliary wheels will be depressed below the wider fixed Wheels and in a ratio inversely proportional to their relative widths.

Now, referring to Figures 1 and 3, it may be assumed first of all, that under non-operating conditions of the cleaner, that is to say, when it is merelystanding on the carpet at rest, the rear fixed wheels I5, I5 will sink into the carpet nap to a depth which may be indicated by the distance a.

The fixed front wheels I3, I3, however, do not penetrate the carpet nap to any appreciable depth for the reason that their combined width plus the lifting effect of the auxiliary wheels 20, 20 under tension, practically removes the entire static load from the fixed wheels and as a result they merely rest on top of the carpet nap as shown in Figure 3.

But with the starting of the cleaner, the suction load and other operating loads are added to the static load with the result that the rear wheels will penetrate the carpet nap to a still greater depth indicated by a, whereas the wide front wheels l3, l3 will now be depressed to a somewhat less depth, indicated by b, with the auxiliary wheels being forced deeper into the carpet, but in a somewhat lesser degree owing to the increased resistance offered by the carpet nap. (See Figures 4 and 5.) In other words, the cleaner has been depressed bodily but in a relatively greater amount at its rear end than its front end.

Now, if the width of the rear wheels l5, l5 be indicated by an arbitrary value 1 and the combined width of the front wheels I3, l3 and auxiliary wheels 20, 20 represented by the value 1.75 (the front wheels being slightly less than twice the width of the rear wheels), the ratio between the widths of the wheels is obviously l to 1.75. Moreover, it is assumed that a definite relationship exists between the width of the wheels and their capacity to penetrate or sink into the nap of a given carpet and this relationship has been termed the penetration ratio which simply means that the depth of penetration of wheels into the nap of a carpet is roughly, inversely proportional to the relative widths of their tread surfaces. Thus, if the wheels be proportioned as to give a predetermined width ratio between front and rear wheels, the depth of penetration of the wheels is assumed to always be (approximately at least) in inverse proportion to their widthsin this case, 1.75 to 1; that is, the rear wheels will always sink to almost twice the depth of the front wheels regardless of the quality of the particular carpet being cleaned. This ratio obviously, is not the same for all types or designs of cleaners, but nevertheless, it is possible to proportion the width of the wheels so that regardless of variations in the texture and quality of different carpets cleaned, the relative penetration of the front and rear wheels will automatically maintain the nozzle approximately at the proper height above the carpet surface. For example, if the cleaner is transferred from a relatively thin to a thick carpet, as shown in Figures 1 and 4, the rear wheels penetrate to a relatively greater depth than the front wheels and while front wheel penetration will occur, at the same time there will be a bodily tilting or rocking of the cleaner body on the front wheels as a fulcrum, thus raising the nozzle just enough to compensate for the increased depth of penetration of the front wheels into the thicker carpet.

Thus it follows, that regardless of the thickness or quality of the carpet being cleaned, a relative depth of sink or penetration of the carpet nap by the front and rear wheels will approximate the so-called penetration ratio and maintain a uniform nozzle height.

Therefore it is to be observed that the automatic adjustment of the nozzle height for the penetration of the wheels into the carpet nap may be controlled or regulated automatically and within the cleaner structure by properly proportioning the dimensions and especially the width of the tread surfaces of the wheels, although it may be added that varying the relative diameters of the front and rear wheels is also a factor in establishing an effective penetration ratio.

And finally, it i to be noted that the presence or use of the auxiliary wheels 20, 20 is not altogether essential to obtaining a satisfactory arrangement for obtaining automatic nozzle height adjustment. In other words, the auxiliary wheels may be omitted entirely, and, by increasing the tread width (and perhaps the diameter) of the front wheels, the required relationship between the carpet penetrating ability of the front and rear wheels can be established and a correct nozzle height for effective cleaning malntained for all grades of carpet. This preferred form of the invention has been fully disclosed and claimed in a co-pending application.

A modified arrangement of the automatic adjustment mechanism is shown in Figures 6 and 7, wherein the rear supporting wheels are mounted for limited vertical adjustment and are operatively connected with the auxiliary wheels associated with the front supporting Wheels.

For convenience, the several wheels will bear the same designation a before, inasmuch as their general arrangement remains the same. Thus, the front supporting wheels l4, id have their bearings fixed with relation to the cleaner casing and the auxiliary wheels 20, 20 are adjustable vertically, being journalled at the outer ends of pivoted brackets 25, 25, which in this instance are inclined at an angle of approximately 45 to the horizontal instead of bein arranged-horizontally as before. To accommodate this angular position of each auxiliary wheel supporting lever 25, 25, necessitates a slight alteration in the design of each supporting bracket 26 but otherwise it is similar in all respects to the mounting of the auxiliary wheel in the previou disclosure.

Referring now to the rear wheel mounting, the wheel supporting bracket which heretofore was fixed to the underside of the casing, now'becomes a pivoted bracket 21 carrying at its outer end an axle 28 on which the rear wheels l5, l5 are journalled. The bracket 21 is pivotally mounted on a supporting plate 20 riveted to the underside of the cleaner casing I. And finally, the rear wheel supporting bracket 2'! is connected with each of the auxiliary Wheel supporting brackets 25 by means of connecting rods 30, 30 having pivotal connection with said brackets intermediate their ends and extending from front to rear. Thus it follows, that the auxiliary front Wheels 20, 20 and the rear supporting wheels 15, I5 are interconnecting so that they move or shift together, although it should be further pointed out that whereas the front auxiliary wheels 20, 20 are positioned forwardly of their axis of bodily movement, the rear supporting wheels l5, l5 are normally positioned rearwardly thereof, to the end that their movement relative to the cleaner casing is in the opposite direction. In other words, if the front auxiliary wheels 20, 20 are swung downwardly in a direction away from the underside of the cleaner casing, the rear supporting wheels are correspondingly shifted upwardly or towards the cleaner casing and vice Versa. The reason for this arrangement will now be described:

To understand the advantage of this arrangement, it is only necessary to review the previous discussion to recall that the auxiliary wheels 20,-

20 being considerably narrower than the associated front wheels l3, is will tend to penetrate the carpet nap to a greater depth and, under the tension of the torsion springs exerted thereon, serve to support the greater part of the static modified arrangement is to make the adjusting mechanism somewhat more sensitive to variations in carpet conditions.

Having set forth a preferred embodiment of that type of automatic nozzle height adjustment which may be characterized by the maintenance of a substantially definite penetration ratio between the fixed front and rear wheels based on the relative widths of their tread surfaces, the invention will now be set forth in the appended claims.

I claim:

1. A suction cleaner comprising a casing havin a nozzle, supporting wheels mounted to rotate on bearings fixedly secured to opposite ends of said casing, auxiliary wheels associated with the supporting wheels adjacent one end of said casing, supports for said auxiliary wheels permitting the bodily vertical adjustment thereof, and tension means acting through said auxiliary wheels to counterbalance a predetermined portion of the static load of said cleaner. v

2. A suction cleaner, comprising a casing having a nozzle, pairs of supporting wheels journalled to rotate on bearings fixedly secured adjacent opposite ends of said casing, a pair of auxiliary wheels associated with one of said pairs of supporting wheels and mounted on said casing for limited bodily vertical adjustment, and tension means acting through said auxiliary wheels and in a direction to counterbalance substantially the entire static load which otherwise would be supported by their associated supporting wheels.

3. A suction cleaner comprising a casing having a nozzle, supporting wheels mounted to rotate on bearings fixedly secured at opposite ends of said casing, relatively narrow auxiliary wheels associated with the supporting wheels adjacent said nozzle, brackets having pivotal connection with said casing and carrying said auxiliary wheels for limited vertical adjustment, and springs acting on said brackets to exert Dressure in a downward direction whereby said auxiliary wheels act to assume a predetermined portion of the load which otherwise would be carried by the associated supporting wheels.

4. A suction cleaner comprising a casing having a nozzle, a pair of supporting wheels journalled on bearings fixedly mounted on said casing adjacent said nozzle, a pair of supporting wheels similarly mounted adjacent the rear end of said casing, the first mentioned pair of wheels having substantially wider tread surfaces. a pair of auxiliary wheels mounted on said casing in substantially axial alignment with the wheels adjacent said nozzle and for limited vertical bodily adjustment, and springs acting to exert sufficient pressure to depress said wheels into the surface of the floor covering being cleaned and thereby to assume substantially the entire static load which otherwise would be carried by the adjacent supporting wheels.

5. A suction cleaner comprising a casing having a nozzle, supporting wheels journalled on bearings fixedly mounted on said casing adjacent the front and rear ends of said casing, a pair of auxiliary wheels associated with the front supporting wheels and mounted substantially in axial alignment therewith, bearing brackets for said auxiliary wheels pivotally mounted on said casing, and tension means acting on said bearing brackets to depress said auxiliary wheels into contact with the cleaner supporting surface for the purpose described.

6. A suction cleaner comprising a casing having a nozzle at its forward end, a pair of relatively wide front supporting wheels journalled on fixed bearings mounted on said casing adjacent said nozzle, a pair of relatively narrow supporting wheels similarly mounted at the rear end of said casing, a pair of narrow auxiliary wheels mounted substantially in axial alignment with said supporting wheels, bearing brackets for said auxiliary wheels pivotally mounted on said casing to permit a limited vertical adjustment of said wheels, and torsion springs acting on said brackets whereby said auxiliary wheels act to counterbalance slightly less than the entire static load that would otherwise be carried by the adjacent supporting wheels and permit the latter to assume the suction load with limited penetration of the floor covering.

CHARLES H. TAYLOR.

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