Cutlery – Pipe and rod cutters – Rotary
Reexamination Certificate
1998-02-20
2001-03-20
Payer, Hwei-Siu (Department: 3724)
Cutlery
Pipe and rod cutters
Rotary
C030S097000, C030S102000
Reexamination Certificate
active
06202307
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention herein relates to construction, building and maintenance tools. More particularly it relates to hand-held tools for cutting metal and plastic tubing.
2. Description of the Prior Art
In building and home construction, maintenance, remodeling and the like, cutting of metal or plastic tubing is a common activity. Such tubing is commonly cut for such uses as electrical conduits, water and steam pipes, and air or gas conduits or vents. For large projects where a substantial amount of tubing of a few standardized lengths is needed, tube cutting is usually performed at a tubing mill or other central location using large cutting machines, which are either free standing or are mounted on work benches or similar bases. Such large volume machine cutting is not related to the present invention.
At the other end of the spectrum, for small projects where a modest number of lengths of tubing are to be cut and where the cut lengths typically vary from piece to piece, a worker commonly cuts each piece of tubing with a small hand-manipulated tubing cutter. Such a cutter is operated simply by repeatedly hand-rotating the entire cutter around a longer, uncut length of tubing at the desired cut point, with the cutter blades being hand-moved inwardly in incremental steps after each rotation, so that eventually the blades cut through the tubing. Such hand work, while slow, usually involves few cutting operations which are simple and often performed at widely separated times, so that there is little incentive for the use of more complex cutting tools.
There are many intermediate sized jobs, however, such as construction or remodeling of individual houses, addition of rooms or wings to existing houses, or extension of electrical, water or gas lines into patios, gardens, walkways or other areas immediately surrounding an individual house or building, where a substantial amount of tubing must be cut, often to different lengths and at frequent time intervals. However, such jobs usually do not have the few standard lengths to justify mill cutting or a large enough volume of tubing to justify placement on-site of a cutting machine. In addition, such jobs sites are often at remote or unique locations, so that it is not economic to transport the machine to the job site or to modify the job site to accommodate the machine. In the past, tubing cutting on such intermediate sized jobs has therefore been done by a worker using a conventional hand-manipulated tubing cutter as described above, and making the cuts by the same repeated rotations and blade indexing steps used for the small jobs. For an intermediate sized job, such tasks are tedious, require a significant length of time for each cut of be completed, (particularly for larger diameter or thicker walled tubing) and can cause excessive fatigue of the worker's hands, wrists and arms, and may ultimately results in “repetitive stress” injuries to the worker.
SUMMARY OF THE INVENTION
I have now invented a motor driven, hand-held tubing cutter which can be easily operated by a worker to make tubing cuts cleanly and quickly. The device is held generally stationary, and the cutting head is driven by the motor around the tubing to make the cut. The motor is reversible, so that once the cut is made, the motor is reversed (preferably automatically) to return the cutting head and blades to their initial position, so that the tool is reset to receive a subsequent length of tubing for the next cut. The worker does not have to manually rotate the cutter around the tubing, thus essentially eliminating significant strain on his or her hands, wrists or forearms. Numerous pieces of tubing can be easily cut in a short time period without causing any significant fatigue to the worker. The device is sufficiently simple that it can be readily operated in a safe and effective manner not only by trained construction, electrical, plumbing, etc. workers, but also by competent laymen such as “do-it-yourself” homeowners.
In addition, the tool has the distinct advantage that it can be use to cut tubing cleanly and quickly without requiring that the tubing be held in a vise or other clamping tool. In fact, in many cases a worker will be able to hold a length of tubing in one hand and the cutter of this invention in the other hand, and cut the tubing cleanly without requiring any kind of other support for the tubing at all.
Briefly, the tool of this invention has a frame in which is disposed a motor-rotated cutting head into which the tubing to be cut is inserted, one or more cutting blades which are indexedly urged into cutting contact with the tubing wall by the motor-driven rotation of the head, and, once the tubing is cut through, reversal of the driving motors causes the blades to be retracted into the head, resetting the tool for further cutting.
The tool may be used to cut any cuttable metal or plastic tubing, including tubing of aluminum, brass, copper, steel, ABS, PVC, polycarbonate, phenolic, etc. Different diameters of tubing can be accommodated by a single cutter, or preferably there can be a set of cutters of different sizes, so that the cutter of the most appropriate size can be selected for cutting tubing of a particular diameter.
Thus, in a preferred broad embodiment, the invention herein is of a powered hand-held tubing cutter which comprises a frame; a motor mounted on said frame for rotating a cutting head; and a cutting head within said frame and rotatable by said motor, having a central aperture for receiving a length of tubing disposed coaxially of the cutting head, a recess extending radially from said aperture, and cutting means for cutting said tubing disposed in and moveable along said recess and comprising a rotatable cutting blade with a cutting edge capable of being disposed into said aperture; and indexing means cooperating with said cutting means for indexing said cutting means along said recess as said cutting head is rotated by said motor; whereby as said motor rotates said cutting head, said cutting means is moved inwardly along said recess by said indexing means, such that as said cutting blade rotates around said tubing, said cutting edge cuts into said tubing, and each rotation of said cutting head causes said cutting means to move further inwardly and said cutting blade to cut deeper into said tubing.
In another embodiment the invention also involves a cutting head for a hand-held tubing cutter powered by a motor, which comprises: a circular plate having a central aperture for receiving a length of tubing disposed coaxially of said plate; a recess in said plate extending radially from said aperture; cutting means for cutting said tubing disposed in and moveable along said recess and comprising a rotatable cutting blade with a cutting edge capable of being disposed into said aperture; rotation means for cooperation with said motor such that operation of said motor rotates said circular plate; and indexing means cooperating with said cutting means for indexing said cutting means along said recess as said circular plate is rotated by said motor.
Other embodiments and details will be evident from the description below, taken in conjunction with the appended drawings.
REFERENCES:
patent: 2769235 (1956-11-01), Martois
patent: 3370352 (1968-02-01), Steely
patent: 4305205 (1981-12-01), Girala
patent: 4467682 (1984-08-01), Huggins
patent: 4802278 (1989-02-01), Vanderpol et al.
patent: 4890385 (1990-01-01), VanderPol et al.
patent: 4953292 (1990-09-01), Tobey
patent: 5088196 (1992-02-01), Fukuda
patent: 5103699 (1992-04-01), Brown
patent: 5528830 (1996-06-01), Hansen
patent: 121131 (1984-10-01), None
Brown Martin Haller & McClain LLP
Payer Hwei-Siu
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