Implements or apparatus for applying pushing or pulling force – Portable implements or apparatus for tensioning flexible... – Material comprises resilient floor covering
Reexamination Certificate
2000-09-14
2002-04-16
Marcelo, Emmanuel M. (Department: 3653)
Implements or apparatus for applying pushing or pulling force
Portable implements or apparatus for tensioning flexible...
Material comprises resilient floor covering
C294S008600
Reexamination Certificate
active
06371446
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a hand-held pneumatic carpet stretcher. More particularly, this invention relates to a pneumatically actuated carpet stretcher used to eliminate wrinkles and creases during the installation of carpet.
BACKGROUND OF THE INVENTION
During the installation of carpet, carpet stretchers are often used to stretch carpet to eliminate wrinkles and creases. It is common to attach the carpet to a floor mounted wood strip or a tack strip having embedded upwardly extending pins for engaging the carpet. One end of a carpet is attached to the tack strip along one side of a room, and the carpet is then stretched to the opposite side of the room where the opposite end of carpet is secured to an opposite tack strip.
One known tool used to stretch carpet is referred to as a “kicker.” This tool engages the carpet with a gripping head and is propelled forward when the operator repeatedly strikes a knee pad with his or her knee. The kicker is widely used and is popular for its ease of use, light weight, and mobility. The kicker, however, has several disadvantages. For example, carpet installers often incur chronic knee and back injuries from the repeated kicking motion during operation of the kicker.
Although carpet installers make up less than 0.06% of the U.S. workforce, they file 6.2% of all workers' compensation claims for traumatic knee injury. This rate is 108 times the expected rate and is the highest rate of any occupation reporting such claims.
To alleviate this problem, hydraulic and electric carpet stretchers have been suggested. The hydraulic powered carpet stretcher, however, is susceptible to undesirable hydraulic fluid leakage problems. An electric powered carpet stretcher, on the other hand, may create a dangerous electrical shock hazard. In addition, hydraulic and electric carpet stretchers are generally large, heavy and cumbersome, and therefore difficult to use.
Pneumatic carpet stretchers, conversely, are desirable because they are not susceptible to the hydraulic fluid leakage and electrical shock hazards to which hydraulic and electric carpets stretchers may subject. Pneumatic carpet stretchers, moreover, have a greater power to weight ratio than hydraulic and electric carpet stretchers. In addition, prior art pneumatic carpet stretchers are complicated, susceptible to large side loads, and have many moving parts. These pneumatic carpet stretchers, therefore, are more expensive to maintain.
Accordingly, there continues to be a need for a carpet stretcher that is light, easy to use, easy to maintain, and portable, but that does not cause the undesirable knee and back injuries to carpet installers that the kicker-type devices cause.
SUMMARY OF THE INVENTION
The invention is a hand-held pneumatic carpet stretcher powered by an associated air compressor or other source of compressed air. The carpet stretcher is used to stretch carpet and eliminate wrinkles during the installation of carpet.
The disclosed carpet stretcher includes two pneumatic cylinders that each has a bore formed therein. Each cylinder includes a piston configured to be sealingly received within the bore so that the piston forms an extension chamber and a retraction chamber within the bore. Each piston is operatively connected to a proximal end of a piston rod, which are connected to each other at their distal ends by a piston rod connector. A gripper plate is operatively coupled to the piston rod connector.
A multi-port air valve includes a pneumatic portion and an atmospheric portion, and is configured so that the pneumatic portion includes an extension port and a retraction port. The atmospheric portion includes an air compressor port, an extension vent and a retraction vent. The air valve is configured so that the air compressor port receives compressed air from an associated air compressor and directs the compressed air to the extension port or the retraction port.
The extension and retraction ports are in communication with the extension and retraction chambers, respectively. The retraction vent is open to the atmosphere when the cylinders are in an extension mode, and the extension vent is open to the atmosphere when the cylinders are in a retraction mode.
A user-operable button is operatively coupled to the air valve and is used to control the directing of compressed air. The button includes a palm lever and a valve stem, and is positioned on a rear portion of the hand grip so that the palm lever is aligned with and parallel to the hand grip. This permits a user to operate the button with the user's palm.
A stretcher head includes pile teeth to grip the carpet. The housing encloses the pneumatic cylinders and the air valve. A face plate includes auxiliary teeth formed on a bottom side of the face plate, and is removably attached to a front portion of the housing. A hand grip is attached to a top surface of the housing.
REFERENCES:
patent: 2631403 (1953-03-01), Hopkins
patent: 3963216 (1976-06-01), Victor
patent: 3980274 (1976-09-01), Ebert
patent: 4008879 (1977-02-01), Youngman
patent: 4042211 (1977-08-01), Hammond et al.
patent: 4084787 (1978-04-01), Kowalczyk
patent: 4627653 (1986-12-01), Koroyasu
patent: 5145225 (1992-09-01), Muller et al.
patent: 5228660 (1993-07-01), Massicotte
patent: 5472170 (1995-12-01), Anasson
patent: 5938182 (1999-08-01), Goodrich et al.
Bartz Robert A.
Gauthier Kenneth C.
Cohen, Esq. Eric D.
Marcelo Emmanuel M.
Welsh & Katz Ltd.
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