Machine element or mechanism – Elements – Cams
Reexamination Certificate
1999-09-21
2001-06-12
Calvert, John J. (Department: 3765)
Machine element or mechanism
Elements
Cams
C074S56800M, C074S5680FS, C074S56800M, C074S56800M, C074S569000, C029S402090, C029S402110, C029S402120, C029S402140
Reexamination Certificate
active
06244133
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to a cam lobe cover and cam follower for use in the doffing mechanism of an open-end textile fiber spinning machine.
In the process of making yarn from textile fibers, raw fibers, whether synthetic or natural, are generally supplied to a carding machine, which typically forms the fibers into a thin web, which is subsequently condensed into a generally elongated cylindrical form, known as sliver. The sliver is then transferred from the carding machine, usually in barrel-type containers, known as “cans.” The cans of sliver may then be transferred to a roving machine, draw frame, or the like for further processing.
Eventually, the sliver is presented to a spinning machine, such as a ring spinning or rotor spinning machine. In a ring spinning operation, the sliver is twisted through means of a traveler carrying the sliver at high speeds around a ring, which encircles a reciprocating bobbin or package, on which the ring-spun yarn is deposited. In rotor spinning the sliver is separated into individual fibers and fed into a rotor rotating at thousands of revolutions per minute. The fibers are thrown outwardly within the rotor by means of centrifugal force and are rotated in a yarn, which is pulled from the rotor and wound directly onto packages. These packages, once filled, are removed, or “doffed,” from the rotor spinning machine. In certain machines, this doffing operation is performed automatically.
One particular rotor spinning machine, specifically, the Autocoro® machine, manufactured by Schlafhorst of Germany, includes an automatic doffing system for doffing your packages. The system includes linkages for physically removing the package from the machine. A housing for the linkages is provided which includes a toothed gear with a cam surface, on which a follower rides during the automatic doffing process. Over time, this gear, which is made of nylon, tends to wear and must be replaced, together with replacement of the follower. Replacement of the gear typically occurs concurrently with rebuilding of the linkage housing, or “box,” and removal of the box from this rotor spinning machine requires the machine to be stopped for approximately an hour while a replacement box is installed.
Accordingly, it would be desirable to improve the longevity of the cam and follower in the box and to reduce the downtime of the rotor spinning machine while such components are being replaced.
SUMMARY OF THE INVENTION
It is, therefore, the principal object of this invention to provide a cam and follower system for a rotor spinning machine.
Another object of the present invention is to provide a cam lobe cover and follower for a rotor spinning machine.
Still another object of the present invention is to provide a method of changing cam surfaces in a rotor spinning machine.
Generally, the present invention includes a cam lobe cap, or cover, which is placed over the cam portion of the cam member, or cam gear, of an automatic doffing box for a rotor spinning machine. The cam cover, or sleeve, is preferably formed of metal, such as steel or stainless steel, and includes a generally cylindrical cap portion for covering the first cam portion of the cam gear, and a second portion standing upwardly from the cap portion for covering a second cam surface of the cam gear.
When the cam surfaces of a cam gear become worn, the cam lobe cover of the present invention is installed on the cam gear, with the cam gear remaining in place within the automatic doffing system. This reduces the downtime of the machine since the cam gear does not have to be removed from the machine. Preferably, once the cam lobe cap of the present invention is installed, a new cam follower designed in accordance with the present invention will also be installed for engaging and following the cam surfaces defined by the cam cover.
The cam follower is preferably of a ball bearing design, having a steel, or stainless steel, outer surface. The follower can be a bushing such as a bushing model number R1560ZZ, manufactured by MNB Company of Massachusetts. The follower is of smaller diameter than the follower originally provided in the automatic doffing system, since the clearance between the new cam surface provided by the cam cover and an intermediate wall of the cam gear is less than the distance between the intermediate wall and the original camming surfaces.
The present invention also includes a method of changing the cam surfaces of an automatic doffing system by first inserting a cam cover over existing cam surfaces and then by installing a cam follower of smaller diameter.
REFERENCES:
Schlafhorst® Spare Parts Catalog Pages.
Donald Bryson W.
Henry Timothy
Calvert John J.
Hurley Shaun R.
Leatherwood Walker Todd & Mann, P.C.
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