Brushing – scrubbing – and general cleaning – Machines – With air blast or suction
Reexamination Certificate
1999-06-30
2001-06-12
Warden, Sr., Robert J. (Department: 1744)
Brushing, scrubbing, and general cleaning
Machines
With air blast or suction
C015S389000, C015S392000
Reexamination Certificate
active
06243917
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to vacuum cleaner heads having a rotatably mounted brush. Such vacuum cleaner heads may be used with upright vacuum cleaners, canister vacuum cleaners, central vacuum cleaners and the like.
BACKGROUND OF THE INVENTION
Typically, vacuum cleaners use a vacuum cleaner head having a dirty air inlet which is in flow communication with a source of suction (e.g. a motor driven fan unit). When the vacuum cleaner is turned on, the suction source creates a low pressure area which draws air into the dirty air inlet. Dirt particles and the like are entrained in the air flow and transported by the air flow to a dirt separation mechanism provided with the vacuum cleaner. In order to assist the entrainment of dirt particles and the like in the air stream entering the dirty air inlet, an agitator (e.g. a rotatably mounted brush) is provided. The rotation of the brush agitates the surface (e.g. carpet) over which the vacuum cleaner head travels. This agitation disturbs the dirt which is in the carpet so that it may more easily be entrained in the air entering the dirty air inlet.
It is know in the art to mount the brush in a fixed position in the vacuum cleaner head. In order to accommodate different surfaces (eg. carpets having different pile heights), it is known to manually adjust the height of the brush with respect to the dirty air inlet. Automatic adjustment controls for adjusting the height of the brush with respect to the dirty air inlet are also know. One example is shown in U.S. Pat. No. 2,614,283 (Thornwald). According to this patent, a pivotally mounted nap engaging structure is provided. The structure is pivoted about a pivot point positioned rearward of the brush.
SUMMARY OF THE INVENTION
The instant invention discloses a pivoting structure for adjustment of the height of the brush with respect to the dirty air inlet. The forces produced due to the rotation of the brush tend to cause the brush to move downwardly. For the brush to float freely, this downward force must be offset by an oppositely directed force (eg. an upwardly directed biasing force). By pivotally mounting an upwardly biased pivot member to the casing of the vacuum cleaner head at a position forward of the brush, at least some of the forces produced due to the rotation of the brush may be transmitted to the casing by the pivot member. Thus, the biasing member may exert a reduced upward force to offset the downward force produced by the rotation of the brush (compared to if the pivot arm were mounted to the rear of the brush). As the force exerted by the biasing member is reduced, the brush may float more freely. Thus the brush may move more easily in the vertical direction in response to the pile of the carpet which it encounters
In accordance with the instant invention, there is provided a vacuum cleaner head for cleaning a surface comprising a casing having a lower surface, a front end, a rear end and an air flow path, the air flow path including a dirty air inlet provided in the lower surface, a brush rotatably mounted above the dirty air inlet and movably mounted with respect to the dirty air inlet between a lowered position and a raised position, the brush having a longitudinally extending central axis, a pivot arm having a first end connected to the brush member and a second end pivotally mounted with respect to the casing at a position forward of the central axis; and, a biasing member to bias the brush to the raised position wherein the rotation of the brush produces a force pivoting the brush towards the dirty air inlet.
In accordance with another embodiment of the instant invention, there is provided a vacuum cleaner head for cleaning a surface comprising a casing having a lower surface, a front end, a rear end and an air flow path, the air flow path including a dirty air inlet provided in the lower surface, a brush rotatably mounted above the dirty air inlet and movably mounted with respect to the dirty air inlet between a lowered position and a raised position, the rotation of the brush producing a force pivoting the brush towards the dirty air inlet, the brush having a longitudinally extending central axis, pivot means for pivotally mounting the brush member to the casing at a position forward of the central axis, the pivot means positioned to transmit at least a portion of the force to the casing, and biasing means to bias the brush to the raised position.
In one embodiment, the first end is disposed upwardly with respect to the second end when the brush is in the raised position.
In another embodiment, the pivot arm extends upwardly at an angle to the horizontal, the angle selected for transmitting a portion of the force produced by the rotation of the brush to the casing.
In another embodiment, the force comprises a downward component and the angle is selected for transmitting at least a major portion of the downward component to the casing. The angle may be from 25 to 65°, preferably from 35-55° and more preferably from 40-50°.
In another embodiment, the brush is rotatably mounted about an axle and the axle is rotatably received in the first end.
In another embodiment, a pivot arm is positioned adjacent each lateral side of the brush and the brush is rotatably mounted in the first ends.
In another embodiment, the vacuum cleaner head further comprises a mounting bracket provided adjacent each lateral side of the brush, each mounting bracket having an inner side facing a respective lateral end of the brush for pivotally receiving thereon the second end of the respective pivot arm and an outer side to attach the mounting bracket to the casing, at least one upper stop member provided on an inner side to engage the pivot arm when in the raised position and at least one lower stop member provided on an inner side to engage the pivot arm when in the lowered position. The biasing member may comprise a generally U shaped leaf spring which is positioned between the mounting bracket and the brush. The spring may have a first portion that abuts against the lower stop and a second portion that is drivenly connected to the pivot arm.
REFERENCES:
patent: 1904972 (1933-04-01), Willis
patent: 1953617 (1934-04-01), Kitto
patent: 2020600 (1935-11-01), Beckef
patent: 2416420 (1947-02-01), Taylor
patent: 2432086 (1947-12-01), Boisselier
patent: 2614283 (1952-10-01), Thornwald
patent: 2672643 (1954-03-01), Langille
patent: 2753585 (1956-07-01), Eberhart
patent: 3012267 (1961-12-01), Kemnitz
patent: 4951347 (1990-08-01), Star et al.
patent: 5297312 (1994-03-01), Zuiderveen et al.
patent: 1124463 (1982-06-01), None
patent: 1281858 (1991-03-01), None
patent: 2020984 (1991-07-01), None
patent: 2169591 (1996-03-01), None
Bereskin & Parr
Fantom Technologies Inc.
Mendes da Costa Philip C.
Snider Theresa T.
Warden, Sr. Robert J.
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