US2651796A - Carpet sweeper - Google Patents

Description

P 1953 R. s. WAGNER ET AL 2,651,796

CARPET SWEEPER Filed Nov. 13, 1948 2 Sheets-Sheet l M15 m 25 16 20 l Lg INVENTORS ROBERT S. WAGNER 21 071250 5 JOHN M S BY ALBERT J. Duwa ATTORNEY Sept. 15, 1953 R. s. WAGNER ET AL CARPET SWEEPER 2 Sheets-Sheet 2 Filed Nov. 15, 1948 INVENTORS RoeeR-r S.WA6NER Joe-m M HIMES BY ALBaR-nLDuwE ATTORN Y Patented Sept. 15, 1953 CARPET SWEEPER Robert S. Wagner, John M. Himes, and Albert J.

Duwe, Milwaukee, Wis., assignors to E. R. Wagner Manufacturing Company, Milwaukee, Wis., a corporation of Wisconsin Application November 13, 1948, Serial No. 59,792

l Claims.

This invention relates to improvements in carpet sweepers, particularly of the self-adjusting type and to improvements in the end plates of such sweepers.

Heretofore carpet sweepers by varying the downward pressure applied to the handle have been self-adjusting to press the bristles of the brush into the pile of the carpet. In such sweepers the brush and the wheels are independently iloatably mounted with respect to the sweeper casing and by varying the downward pressure on the casing the spring supports for the wheels are deflected and the casing lowered to bring greater downward pressure on the brush to bring it into closer contact with the pile of the carpet irrespective of the depth to which the wheels may penetrate. Such sweepers, however, used supporting springs for the wheel mountings which were stiff enough to require the application of downward pressure on the handle to effect the desired adjustment. The necessity of not only applying downward pressure but of also applying the correct amount of downward pressure made the work of the sweeper operator burdensome and often inefficient.

During certain climatic conditions, carpet sweepers become so charged electrostatically that dust and lint form in layers on certain parts of the sweepers and fail to properly enter the pans. When the layers become too thick, or

the electrostatic charge is grounded, such layers will be re-deposited on the floor or carpet instead of in the dust pans.

It is an object of this invention, therefore, to provide a carpet sweeper that will be self-adjusting to comply with varying carpet and floor conditions without the necessity of applying any amount of downward pressure to the sweeper,

handle other than that inherent to the operation. Such a sweeper will be palm-operated, the only pressure for its operation being that necessary to move the sweeper back and forth over the floor or carpeting.

Another object of this invention is to provide a sweeper casing in which the opportunity for the creation of undesirable electrostatic charge is lessened and which is also economical to manufacture.

The first of these objects is obtained by utilizing springs for the individual wheel mounts, the vertical support provided thereby being soft enough to permit the casing and the brush to float on the carpet and to settle down to their lowest limit with respect to the wheels when the thinness of the nap or pile of the carpet so requires without the use of downward operatorapplied pressure on the handle. To have such soft vertical support and still supply sufiicient horizontal force on the wheels to maintain proper driving contact with the brush pulleys the springs are anchored relatively close to the wheel axis and have horizontal portions over twice the length of the vertical distance between the spring anchor and the wheel axis. Thus the vertical reaction on the spring operates through a long lever arm and has a high moment of force readily deflecting the spring while the horizontal reaction operates through a short lever arm and has a low moment of force which is readily resisted by the spring. If this expedient, because of the overall softness of the springs, does not furnish enough horizontal force, the loss is offset and such horizontal force as is supplied by the soft spring is supplemented by using stops on the casing which engage the wheel supports at an angle to the vertical to limit the downward vertical movement of the casing and to provide a horizontally reacting component of force urging the wheel supports inwardly toward the brush pulley. Thus, as the sweeper is moved to and fro with the handle resting in the palm of the operator, the weight of the easing (both static and dynamic) plus any small vertical resultant force arising from the downward inclination of the handle will urge the casing down toward the carpet or floor with sufficient force to overcome the vertical resistance of the springs in the individual wheel mountings and permit the casing to lower with respect to the wheels until the dust pans substantially ride over the top of the carpet nap. In this position the brush will usually properly engage the nap. However, if there is too close an engagement between the brush and nap the brush tends to stop rotation. If this should occur the increased resistance to horizontal movement will produce a vertical component which will cause the casing to settle until the stop on the casing limits such movement and simultaneously brings into effect the additional horizontal force sufficiently increasing the driving engagement between the wheels and the brush pulley to keep the brush rotating.

The second of these objects is obtained by using metal die-cast end plates. Such end plates provide a means for accurately and easily locating the stops for limiting vertical movement and creating horizontal components of force. The location of these stops is crucial and by integrally casting them with the end plate their 10- cation and shape are consistently held. Such die-cast end plates also lessen the assembly costs as the pivots for mounting the dust pans and the stops and bearings for the combs are all formed on the inside of the end plate at the time of casting. In addition to these advantages the die cast end plate helps lessen electrostatic charges. The end plates being conductors are electrically connected with the dust pans, the combs, and the casing top (if it be metal), and the opportunity for electrostatic charges is lessened because of the lower number of electrically insulated parts which may become condenser plates.

The novel features, which are considered characteristic of the invention, are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings, in which:

Fig. 1 is a fragmentary top plan view showing the left-hand part of a carpet sweeper embodying the present invention, a part of the sweeper casing being broken away and shown in section for sake of clarity in illustration;

Fig. 2 is a view in elevation of the lefthand end of thesweeper viewed in Fig. 1 with. the end bell removed;

Fig. 3 is a view similar to the view in Fig. 2 showing the relative position of the parts when the sweeper casing is lowered to its lower limit;

Fig. 4 is a fragmentary top plan view showing the right-hand part of a modified form of a carpet sweeper embodying the present invention, a part of the sweeper casing being broken away and shown in section. for clarity in illustration;

Fig. 5' is a view in elevation of the righthand end of the modification of the sweeper viewed in Fig. 4 with the end bell removed and with the parts shown in the relationship assumed when the casing is in its lowest position; and

Fig. 6 is a perspective view of the inner side of the metal die-cast end plate shown in the modification of the sweeper viewed in Fig. 4.

The sweeper shown in the drawings, with exception of the differences hereinafter described in particular, is of substantially identical construction with the sweeper described in Patent No. 2,228,528, issued January 14, 1941, to Swift Miller, and reference is made to that patent for a complete description of the standard parts of the carpet sweeper embodying this invention.

Referring to the drawings by reference numorals, the carpet sweeper comprises a casing made up, in the modification of Figs. 1, 2 and 3, of a pair of wooden end plates is held together by wooden side rails l4 and, in the modification of Figs. 4, 5 and 6, of a pair of die-cast metal. end plates 12 held together by metal side rails is covered by a sheet metal top I8. Metal end bells or cover plates 25! complete the casing and enclose the floor wheels 35 and their supporting mechanism. A rubber bumper 22 encircles the casing in the customary manner. Dust pans 2 with their lower surfaces lying substantially in. the same horizontal plane, and brush-cleaning combs 26, are all pivoted to the end plates in the usual manner. A rotatable brush 28 with pulleys 3B and bearing sockets 32 is fioatably mounted in the casing by spring-mounted trunnions 34 carried in the end bells 20 in the manner described in said patent.

Each end of the casing is supported by a pair of wheels 36 rotatably mounted on stub axles carried by wheel supports 38 fioatably mounted to the end plates by brackets 45 in the manner described in saidpatent. Each of the wheels 35 has a hub which is rotatable on the stub axle. The metal end bells 20 engage the outer ends of the hubs to prevent the wheels from being displaced from the ends of the stub axles. The brackets 40 at each side have an outwardly displaced portion which provides a socket or guide for the inner end of the wheel supports 38 and in cooperation with the end plates Iii (or ii in the case of the modification of Figs. 4, 5, and 6) constrains such supports to horizontal and vertical movement in a vertical plane. Each of the inner ends of such wheel supports has a longitudinal slot through which a pin extends to limit the horizontal sliding movement of such supports while constraining such. support to swinging movement- With. such. organization the wheels have independent universal. planar movement to uniformly maintain engagement with the brush pulley 30, and. at the same, time to permit the casing tohave up and. down movement with. respect to the wheels and the surface on which they are rolling.. Inv said. patent a stop is provided for each. wheel. support by the guiding portions of thebracketfor the sole function of limiting the downward movement of the easing with respect to the wheels and the, surface on which they roll. In. the carpet sweeper described herein. the stopsin thecase of the wooden end plate 10 consist of circular studs 42 and in the case of the die-cast end. plate [.2 consist, of raised curved. members. 44 and have a two-fold function. The steps. provide the lower limit of the downward movement of the. casing with respect tothe wheels. and when. operating as such limit they also provide an additional horizontally acting forcev component which urges the wheel supports inwardly and the wheels into tighter engagement with the brush pulley 39. As shown in Fig. 3, if a. vertical force of the magnitude indicated by the vector line V were exerted on a stud 42, this force, when. transmitted to the circular end of the wheel support 38, would produce a horizontal force of. substantially the amount indicated by the vector line H. This arises because the centers of the studs 42 are positioned outwardly of the centers of the circular ends of the wheel supports 38 and in the abutting relation shown in Fig. 3 the line joining respective centers slopes downwardly and inwardly to the. vertical about fifteen degrees' Substantially the same result is obtained when a vertical force acts upon the curved members M. The concave faces of the members 44 engage the circular ends of wheel supports 38 at a common tangential line that slopes upwardly and inwardly to produce a horizontal component for such vertical force. An important feature resides in the fact that the point of contact for the stops and wheel supports lies outside the outer limit of travel of the axis of the wheels caused by contact of such. wheels with the brush pulley. Because of this small errors in the positioning of the stops will not have any deleterious eifect on the optimum wheel to brush pulley relationship. On the other hand, as in the case of said patent, the point of contact is well within such path and small errors in positioning the stops produce large errors in the Wheel to brush relationship. Hence the excessively close manufacturing tolerances formerly required have been eliminated and the cost of manufacture lessened.

The limit of the upper movement of the casing with respect to the wheels is not critical and in the case of the wooden end plate 10 such limit may be determined by the engagement between the lower guiding portion of bracket 40 and the wheel support 38. In the case of the metal diecast end plate l2, raised bars 46 may be used to engage the wheel supports 38 for the upper limit of the casing movement.

In order to have a palm-operated sweeper, it is essential that the casing move downwardly with respect to the wheels under the influence of its own weight (both static and dynamic) and the influence of any vertical component of force resulting from the forward motion force applied to the handle while inclined to the horizontal. It is essential to good sweeping that the casing, in so far as practical, ride with the bottom of the dust pans 24 on the top of the carpet pile. To attain this, the spring mounting between the casing and each wheel must have a light vertical resistance. On the other hand it is also important that such spring mounting have sufficient horizontal resistance to maintain a driving engagement between the wheels and the brush pulley. Therefore, each spring 48 is shaped as shown in Figs. 2, 3, and 4 to have an anchoring portion 5d, a horizontal portion 55, a curved portion 58, a connective portion 60, and a curled end The anchoring portions are engaged by lugs 52 and 54 formed on the bracket it. The lug 54 constitutes a "point of reference and is positioned closely adjacent the wheel support 38. The horizontal portion 56 is relatively long and extends outwardly of the casing almost to the end thereof. The curled end 62 engages grooves provided on the outer ends of the wheel supports 38. With the spring assembled under a predetermined stress, the vertical distance between the wheel centers and the anchoring lugs 54 is less than half the distance from the anchoring lugs Ed to the outermost part of the curved portions 58. Thus the moment of force which tends to deflect the spring 48 as the casing is moved vertically downwardly is much greater than the moment of force which tends to deflect the spring ed as the wheels are moved horizontally outwardly of the casing. The spring 48 will therefore provide a soft support for the casing permitting it to settle in normal operation until the bottoms of the pans 24 rest on the nap and that same Spring will also provide a sufficient horizontal force to maintain driving engagement between the wheels and roller 30. If the brushes engage the nap too deeply, resistance to the forward movement of the sweeper increases and more force must be applied to the handle. This results in an increase in vertical force which moves the casing down to the position shown in Figs. 3 and 4. This develops the extra brushdriving force necessary to keep the wheels from slipping. The sweeper, therefore, automatically adjusts itself to varying conditions of carpet.

In the modification of the carpet sweeper illustrated in Figs. 4, 5 and 6, the end plates l2, instead of being made of wood as is customary, are of metal die-cast in the shape shown in Fig. 6. The outer face of the end plate l2 has formed integrally thereon the curved members 44 and the raised bars 45. The location of these members and bars, having been accurately predetermined and permanently fixed in the mold, will always be the same in each piece. The inner face of the die-cast end piece is shown in Fig. 6. It has a flange 64 which extends across its top, down its sides, and along small portions of its bottom. A deeper flange 65 forms a ledge which cooperates with the dust pans. Pins 68 on which the dust pans are pivotally mounted, pads 10 with recesses 12 and pins Hi providing bearings and stops for the brush combs, and a pad 16 with a bail bearing T8 are integrally formed on the inner face of the plate 42. By using a die-cast end plate as above described, the operations of: spotting and drilling the holes for the various bearings and spotting and drilling holes for and setting the various pins for pivots and stops are all accomplished as a single operation at the time of casting the piece. This not only lessens the cost of assembly but also provides for an accurate duplication of each end plate. Another important advantage of the die-cast metal end plates resides in the fact that they are electrical conductors and electrically connect as a single unit the combs, the metal casing top, the dust pans, and the end plates. Thus all plate-like metal parts, which would otherwise be insulated and become the opposing plates of an electrostatic condenser, are united and the opportunity for electrostatic condenser action considerably lessened. Because of this, the creation of electrostatic charges which attract dust and lint is substantially reduced.

Although only several embodiments of the invention are shown and described herein, it will be understood that this application is intended to cover such other changes or modifications as come within the spirit of the invention or scope of the following claims.

We claim:

1. In a carpet sweeper, a casing, a rotary brush floatably carried by said casing and having a wheel-engaging pulley, a wheel support mounted on said casing and guided to have limited independent horizontal and vertical movement in a vertical plane relative to said casing, said support having on its outer end an axle for supporting a wheel and a camming surface adapted to provide an inwardly horizontally acting force upon engagement with a stop on said casing, a wheel rotatably mounted on said axle and engageable with the floor and said pulley to rotate said brush, a spring carried by said casing and engaging said support in a manner to press said wheel downwardly and inwardly of said pulley, said downward pressure being small enough to permit said casing of its own weight plus the influence of any vertically acting component of the force normally applied to said sweeper to produce horizontal motion thereof to flex aid spring and move downwardly of said wheel until said casing is in contact with a floor covering, said inward pressure being sufficient to establish a driving connection between said wheel and said pulley, and a stop on said casing having a portion adapted to engage with said camming surface to limit downward movement of said casing with respect to said wheel with the periphery of said wheel below the bottom of said casing, said portion and said surface upon engagement providing a horizontal component of force acting on said support to press said wheel inwardly toward said pulley to provide additional 3. A carpet sweeper as claimed in claim 1 in which said camming surface is curved concave inwardly and upwardly with respect to said pulley.

4. In a carpet sweeper, a casing, an end plate for said casing formed of die-cast metal, said plate having formed integrally on the inner side thereof a pin for pivotally mounting a dust pan, a metal dust pan mounted in said casing on said pin, a rotary brush fioatably carried by said casing and having a wheel-engaging pulley, a wheel support of metal mounted on said end plate and guided to have limited independent horizontal and vertical movement in a vertical plane relative to said casing, said support having on its outer end an axle for supporting a wheel and a camming surface adapted to provide an inwardly horizontally acting force upon engagement with a stop on said end plate, a wheel rotatably mounted on said axle and engageable with the floor and said pulley to rotate said brush, a spring carried by said end plate and engaging said support in a manner to press said wheel downwardly and inwardly of said pulley, said downward pressure being small enough to permit said casing of its own weight plus the influence of any vertically acting component of the force normally applied to said sweeper to produce horizontal motion thereof to flex said spring and move downwardly of said wheel until said casing is in contact with a floor covering, said inward pressure being sufficient to establish a driving connection between said wheel and said pulley, a stop formed integrally on the outer side of said end plate and having a portion adapted to engage with said camming surface to limit downward movement of said casing with respect to said wheel with the periphery of said wheel below the bottom of said casing, said portion and said surface upon engagement providing a horizontal component of force acting on said support to press said wheel inwardly toward said pulley to provide additional driving connection therebetween, a metal comb mounted in said casing and adapted to engage said brush, a pad integrally formed on the inner side of said end plate and having a recess adapted to pivotally mount said metal comb, and a projecting pin integrally formed on the inner side of said end plate for limiting the move ment of said comb.

- ROBERT S. WAGNER.

JOHN M. H'IMES. ALBERT J. DUWE.

References, Cited in the file of this patent UNITED STATES PATENTS Number Name Date 424,309 Kelley Mar. 25, 1890 486,371 Drew Nov. 15, 1892 1,813,325 Smith July 7, 1931 2,166,977 Smith July 25, 1939 2,228,528 Miller Jan. 14, 1941 FOREIGN PATENTS Number Country Date 441,175 Great Britain Jan. 14, 1936 476,932 Great Britain Dec. 20, 1937

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