Joints and connections – Flexibly connected rigid members – Elastomer interposed between radially spaced members
Reexamination Certificate
2001-04-17
2003-08-05
Browne, Lynne H. (Department: 3679)
Joints and connections
Flexibly connected rigid members
Elastomer interposed between radially spaced members
C403S224000, C403S226000, C015S049100, C015S050300, C015S051000, C029S708000
Reexamination Certificate
active
06602018
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to surface cleaning equipment. More particularly the present invention relates to a novel mechanical coupling for retaining a wiper assembly to a surface maintenance vehicle that preserves the wiper assembly from damage in event of contact with oversize debris, a stationary object or other impediments and obstacles which create significant resistance to the desired motion of the wiper assembly.
BACKGROUND OF THE INVENTION
Surface maintenance vehicles and cleaning devices have a long history subject to gradual innovation and improvement toward improved and oftentimes automated performance in removing debris and contamination from floors. These vehicles and devices may be self-powered, towed, or pushed, and/or manually powered and may carry a human operator during cleaning operations. Such vehicles and devices include scrubbers, extractors, sweepers and vacuums, as well as combinations thereof, intended for cleaning, scrubbing, wiping and/or drying a portion of a substantially flat surface both indoors and outdoors. Many such vehicles and devices employ a squeegee assembly for wiping dry a floor which has been cleaned by application of a cleaning solution of water and a detergent in conjunction with scrubbing action of one or more moving brushes. Accordingly, the squeegee assembly of such prior art cleaning vehicles often mounts at or near the rear of the surface maintenance vehicle to direct the solution to a removal location where the solution (including suspended dirt, particles and contaminants) is removed. In this disclosure, the term “loaded cleaning solution” shall apply to such a cleaning solution after application thereof to a floor or other surface to be cleaned. The cleaning solution is typically supplied to the floor surface through or near rotary scrub brushes operating from a lower portion of the vehicle. The squeegee assembly may include a squeegee supporting member of generally arcuate configuration with two squeegee blades spaced apart and affixed to the supporting member to promote consistent contact with the surface to be cleaned and wiped.
In some prior art cleaning vehicles having two squeegee blades, a vacuum source may couple to the wiping assembly to lift the loaded cleaning solution from the space between the blades to a remote reservoir or other collection unit. The squeegee assembly is often sufficiently wide to at least fully cover the path width of the scrub brushes and/or the wheels of the cleaning vehicle. Consequently, at least the ends of the squeegee assembly tend to be exposed at the sides of the vehicle and are therefore potentially very vulnerable to contact with stationary objects which might be encountered during operation of the vehicle during cleaning operations and when transporting the vehicle between cleaning operations. Solid contact between an end of a squeegee assembly and a stationary object such as, for example, a vertical support column, can result in substantial and costly damage to not only the squeegee assembly but also the surface maintenance vehicle itself resulting in downtime, costly repair and/or replacement of all or a part of the vehicle (as well as the stationary object) and in some circumstances causing damage or injury to the human operator of the vehicle as well.
Releasable squeegee assembly structures for cleaning vehicles and devices have been known in the art, such as that disclosed in U.S. Pat. No. 4,363,152 issued Dec. 14, 1982 to Karpanty. In this prior art reference, a squeegee assembly includes a squeegee-bearing mounting plate having threaded bolts mechanically connected via conventional wing nuts to rear-facing open-ended slots extending from a cleaning vehicle. The resulting metal-on-metal contact between the bolts, slots and nuts provides a so-called “friction fit” attachment with a frictional force magnitude depending on the degree of tightening of the individual wing nuts. In the event the squeegee assembly collides with an unmovable obstacle, presumably each nut and bolt pair moves out of, and disconnects from, its respective slot at some discrete, albeit somewhat arbitrary, level of imparted force. If the nut is in fact overly tight, the release mechanism will not provide for the squeegee to disengage unless and until such level of force reaches said arbitrary level of imparted force, regardless of: (i) the amount of contact time between the squeegee and the obstacle; (ii) the degree of damage incurred by the squeegee; (iii) the elasticity of the collision between the squeegee and the obstacle; and, (iv) the amount of damage incurred by the obstacle. Conversely, if the nut is in fact overly loose, the release mechanism will provide for the squeegee to disengage repeatedly without apparent or desired reason.
Accordingly, the just recited prior art approach and other known assemblies rely on a frictional force developed between opposing metallic surfaces. Unfortunately, as in the reference immediately above, the frictional force is fully dependent upon the degree of manual tightening of a knob or wing nut. One limitation of these known squeegee assembly release structures is that the release force is variable and dependent upon the degree of manual tightening and resulting friction developed between the opposed metallic surfaces.
As stated above, over-tightening may effectively prevent release of the assembly with resulting damage and loss to the cleaning vehicle, the facility being cleaned and even the operator of the vehicle. Inadequate tightening may result in repeated, premature release of the assembly with associated costly downtime, re-cleaning, and re-attachment (again without calibration or other measures to ensure adequate tightening). In addition, when more than one such attachment location must be addressed and suitable mechanically coupled, the possibility of un-even tightening becomes a probability with costly implications similar to those cited above.
SUMMARY OF THE PRESENT INVENTION
The present invention teaches, enables and discloses an improved mechanical coupling for a wiper assembly usable in a surface maintenance vehicle. Such a vehicle includes those self-powered and manually powered cleaning vehicles applied to the task of removing loaded cleaning solution from a cleaned surface and preferably include all such vehicles using an articulated wiper assembly; although rigid or fixed wiper assemblies for such vehicles benefit from the teaching of this disclosure. Such a surface may comprise an interior or exterior floor having some limited porosity but preferably comprising finished concrete (whether painted or sealed), asphalt, ceramic tile, resin-based tile, and the like and including most types of flooring typical of commercial and industrial-grade facilities. However, the teaching hereof finds application in diverse handling of fluids, whether or not “loaded,” naturally-occurring liquid(s) or pure cleaning fluid.
Accordingly, the articulated wiper assembly of the present invention tolerates a wide variety of stresses imparted to the blade portions of a wiper assembly during wiping operations and before becoming temporarily disconnected from a surface maintenance vehicle to which it is coupled. In most embodiments of the present invention, the wiper assembly couples to a mounting plate member coupled to the maintenance vehicle and typically designed to permit the wiper assembly to articulate, or “float,” thereby maintaining contact between one or more wiper blades secured to the wiper assembly and a portion of the surface to be cleaned during operation of the surface maintenance vehicle. An articulated wiper assembly utilizing the teaching of the present invention thus may be raised, lowered, pivoted and/or rotated either passively using gravity or manually using gearing, cables and the like and/or via internal combustion, electric, pneumatic, hydraulic or other motive means.
The improved mechanical coupling of the present invention by using a deformable member adds a modicum of additional travel, while not increasing the degree
Feeny Steven V.
Joynt Daniel L.
Bochna David E.
Browne Lynne H.
Fulbright & Jaworski L.L.P.
Tennant Company
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