Brushing – scrubbing – and general cleaning – Implements – Pipe – tube – or conduit cleaner
Reexamination Certificate
1999-12-23
2002-05-07
Spisich, Mark (Department: 1744)
Brushing, scrubbing, and general cleaning
Implements
Pipe, tube, or conduit cleaner
Reexamination Certificate
active
06381798
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the art of drain or sewer cleaning machines and, more particularly, to a spring clutch arrangement for such machines of the character having a flexible plumber's cable or snake coiled within a belt driven drum from which the snake is withdrawn and inserted into a drain or sewer to be cleaned.
Belt driven drum-type sewer cleaning machines of the character to which the present invention is directed are well-known and are shown; for example, in U.S. Pat. No. 2,730,740 to O'Brien, U.S. Pat. No. 3,007,186 to Olsson, U.S. Pat. No. 3,246,354 to Cooney, et al., U.S. Pat. No. 3,747,153 to O'Neill, U.S. Pat. No. 4,716,613 to Irwin, U.S. Pat. No. 5,031,276 to Babb, et al., U.S. Pat. No. 5,309,595 to Salecker, et al., and U.S. Pat. No. 5,390,389 to Rutkowski, et al. The disclosures of the foregoing patents are hereby incorporated herein by reference for background information. In the foregoing patents, the drum is rotated by an endless belt trained about a motor driven pulley and the outer periphery of the drum or a drum mounted pulley, and in the O'Brien, Olsson, Cooney, et al., and O'Neill, patents the motor support table or platform is secured to a post or posts by thumb screw components or the like to tension the belt for driving the drum in response to operation of the electric motor. In the patents to Irwin, Babb, et al., Salecker, et al., and Rutkowski, et al., a biasing spring arrangement is provided between the machine frame and motor platform for maintaining the driving tension on the endless belt. In belt driven drums of the foregoing character heretofore provided, a tension is maintained on the belt so as to intentionally preclude any slippage between the belt and motor driven pulley. These machines are used by professionals who do not want such slippage. Rather, an operator's skill and experience is relied upon for controlling operation of the drive motor so as to preclude overheating thereof and/or problems attendant to the application of an excessively high torque on the drain cleaning snake during use of the machine. Moreover, there was no slippage between the belt and drive pulley even in those machines which included a spring or springs to tension the drive belt in that the latter springs were intentionally strong enough to preclude slippage. The purpose of the spring arrangement in the prior art was to facilitate a release of the drive belt by pushing against the biasing spring force to displace the drive pulley toward the drum axis to facilitate disengagement of the belt from the drive pulley. Efforts to avoid or minimize damage to the snake and/or drive motor in the machines heretofore available included the use of clutch mechanisms incorporated in the drive pulley, such as that shown in U.S. Pat. No. 5,033,990 to Silverman.
Today, such drain cleaning machines are available to inexperienced operators through the rental market or retail markets, the use of such machines by inexperienced operators can result in the overloading and damaging of the snakes or cables as well as the overloading and damaging of the drive motors. More particularly in this respect, an inexperienced operator is not likely to have a “feel” for the engagement of the leading end of the snake with an obstruction which either cannot be easily penetrated or which interengages with the snake so as to preclude rotation of the leading end thereof, the latter of which can result in damage to the snake and both of which impose an undesirably high load on the drive motor. Some drive motors for such drain cleaning apparatus have a thermal cut-out which will stop the motor if the latter becomes too hot as a result of overloading and, if there is no thermal cut-out, the drive motor can be damaged by overheating. Moreover, even if there is a thermal cut-out, the effect of overheating is cumulative, whereby the life of the drive motor is reduced. While it might be possible to impose a torque on the snake which could result in slippage between the belt and drive motor prior to the latter stopping through the operation of a thermal cut-out or because of a burn-out condition of the motor, such slippage is not intentional, results in extremely high frictional interengagement between the belt and drive motor pulley causing deterioration of the belt. Moreover, since such slippage is not intentional, the drive motor is still subject to the damaging affect of overheating. The end result is high maintenance and/or replacement costs due to damage to one or more of the drain cleaning snake, drive belt and drive motor.
SUMMARY OF THE INVENTION
In accordance with the present invention, a slip clutch arrangement is provided for a belt driven drum-type drain cleaner in which one or more springs of predetermined force bias the drive motor to provide a predetermined tension in the drive belt which provides for slippage between the drive belt and drive pulley in response to the imposition of a predetermined torque on the snake during operation of the apparatus. Accordingly, should the leading end of the snake encounter an obstruction during use of the apparatus which imposes an undesirably high torque on the snake, the drive belt will slip relative to the drive motor pulley so as to preclude rotation of the drum and snake. This advantageously prevents damage to the snake and precludes the imposition of a load on the drive motor causing the latter to overheat. Advantageously, a slip clutch arrangement in accordance with the present invention provides drain cleaning apparatus which can be used by an inexperienced operator, such as a home owner, without potentially damaging the snake and/or drive motor by torsionally overloading the snake and/or thermally overloading the drive motor. In accordance with one aspect of the invention, the drive motor is mounted on a pivotal lever between the pivot axis for the lever and a spring of predetermined force acting against the lever to bias the motor to tension the drive belt. In accordance with another aspect of the invention, the motor is mounted on a reciprocable table which is biased by one or a pair of springs having a predetermined spring force to bias the motor to tension the drive belt. In accordance with yet another aspect of the invention, the spring force is adjustable so that the drive pulley will slip relative to the belt in response to the imposition of different torsional forces on the snake. Accordingly, snakes of different diameter can be used with a given drain cleaning machine by adjusting the spring force to provide for slippage between the drive belt and drive pulley at a torque which is appropriate for the particular diameter of snake being used.
It is accordingly an outstanding object of the present invention to provide improved belt driven drum-type drain cleaning apparatus which avoids damage to the plumbing snake and/or drive motor of the apparatus as the result of the imposition of an undesirably high torque on the snake during use of the apparatus.
Another object is the provision of improved apparatus of the foregoing character wherein slippage between the drive belt and drive motor pulley is intentionally achieved in response to the imposition of a predetermined torque on the drain cleaning snake.
A further object is the provision of improved apparatus of the foregoing character wherein the drum drive motor is spring biased to tension the drive belt using a predetermined spring force which results in slippage between the belt and drive pulley in response to the imposition of a predetermined torque on the drain cleaning snake.
Still another object is the provision of improved apparatus of the foregoing character wherein the spring force is adjustable enabling varying the tension on the drive belt and thus the predetermined torque on the drain cleaning snake at which slippage occurs between the drive belt and drive motor pulley.
Still a further object is the provision of improved apparatus of the foregoing character which enables operation of the apparatus by inexperienced persons wh
Babb Larry F.
Rutkowski Michael J.
Emerson Electric Co.
Spisich Mark
Vickers Daniels & Young
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