Measuring and testing – Testing sealed receptacle
Reexamination Certificate
1999-05-05
2001-06-26
Fuller, Benjamin R. (Department: 2855)
Measuring and testing
Testing sealed receptacle
C073S834000
Reexamination Certificate
active
06250135
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to the manufacture of container ends having a pull tab and more particularly to the detection of a defect occurring during the manufacture of container ends.
BACKGROUND OF THE INVENTION
Apparatus for the manufacture of container ends having pull tabs secured thereon for opening the container end is illustrated in a brochure published by The Stolle Precision Tool Company which is incorporated herein by reference thereto. As illustrated in the brochure, the container end manufacture involves two distinct operations. In one operation, a plurality of container end blanks are positioned in openings in a conveyor which is moved in a stepping operation so that the container end blank is moved between upper and lower dies at different positions to have a particular operation performed thereon. As illustrated in the brochure, a container end blank is intermittently moved to different positions to have a rivet stud formed therein. After that the score lines and indentation lines are formed therein. At the next position, the pull tab is placed over the rivet stud which is then smashed to hold the pull tab onto the container end blank. As illustrated in the brochure, the pull tabs are formed in a separate series of operations and, after being fully formed are positioned with an opening therein in alignment with the rivet stud. As illustrated in the brochure, the pull tabs are formed using a continuous strip of metal that is intermittently moved through a plurality of stations. As the pull tabs are being formed, they remain attached to the continuous strip of metal by one or more carry strips. The brochure illustrates two spaced apart carry strips between the tail of the pull tab and the continuous strip of metal. In another type of apparatus for the manufacture of the pull tab, only one carry strip is used and is located between the nose of the pull tab and the continuous strip of metal. The purpose of the carry strip or strips is to ensure that the pull tabs move with the continuous strip of metal. When the pull tab is separated from the continuous strip of metal to be placed over the rivet stud, a projecting portion of the carry strip remains attached to the nose of the pull tab or projecting portions of the carry strips remain attached to the tail of the pull tab. In either case, it is necessary to wipe down the pull tab to remove these projecting portions so that they will not result in deleterious contact with the user of the container on which the container end is secured either in the opening or using of the container. Therefore, the next position in the formation of a container end with a pull tab secured thereon is known as the tab wipe down assembly. In this position an upper die is provided with a portion to fold the projecting portion or portions so that the portion or portions have substantially the same configuration as the adjacent portions of the nose or tail of the pull tab. The upper die is also provided with a pilot that enters the finger hole of the pull tab to prevent lateral movement of the pull tab during the operation of the wiping operation so that no undue force is placed on the rivet to cause damage thereto. In the apparatus illustrated in the brochure, the conveyor carrying the container blanks has three rows of openings and moves at the rate of speed so that more than six hundred cans per minute in each row are passed through the various positions. Therefore, it is desirable to detect any defect in the production of the container ends as soon as possible to avoid the waste of a considerable amount of metal. There are many different types of causes which result in defects associated with the container ends. As illustrated on the front page of the brochure there are a variety of container ends having a pull tab secured thereon.
BRIEF DESCRIPTION OF THE INVENTION
This invention provides apparatus for detecting a defect in the manufacture of container ends having a pull tab secured thereto wherein the defect prevents a portion of the detecting apparatus from reaching its lowermost position in relation to the lowermost position of an upper die in which it is located and is preferably located in the tab wipe down assembly of apparatus used in the production of a variety of container ends having a pull tab secured thereto as described above.
In a preferred embodiment of the invention, the detecting apparatus comprises a modification of the upper die used in the tab wipe down assembly. At this location, the lower die is stationary and the upper die moves in a longitudinal direction toward or away from the lower die. The detecting apparatus moves with the upper die and is mounted in the upper die for limited longitudinal movement in each direction relative thereto. In the preferred embodiment of the invention, the upper die for use with the detecting apparatus comprises three separable parts which are held together by conventional apparatus. Each of the first and second parts have a passageway extending therethrough and the third part has a passageway extending partially therethrough. The longitudinal axes of the passageways are in alignment and are parallel to the longitudinal axis of the upper die but off-set therefrom.
The detecting apparatus is mounted in the passageways for movement with the upper die and for longitudinal movement relative to the uppper die. At least portions of the detecting apparatus and at least portions of the passageways have transverse configurations to prevent relative rotational movement between the upper die and the detecting device. The lowermost portion of the detecting apparatus has a transverse configuration corresponding to but slightly smaller than the finger hole in the stay-on-tab so that in normal operation, the lowermost portion of the detecting apparatus will be in its lowermost position when the upper die is in its lowermost position. The detecting apparatus is resiliently urged into its lowermost position.
Sensing apparatus is mounted at a fixed location on the upper die for movement therewith. At least a portion of the sensing apparatus and at least a portion of the detecting apparatus are located so that the sensing apparatus will generate a signal when the detecting apparatus is not in its lowermost position when the upper die is in its lowermost position.
In the normal operation of the tab wipe down assembly, the lowermost portion of the detecting apparatus will enter the finger hole of the stay-on-tab as the upper die is moving toward its lowermost position. A portion of the tab wipe down assembly will contact a portion of the tab and apply a force thereto a portion of which extends in a lateral direction. However, lateral movement of the pull tab is prevented by contact of the portion of the stay-on-tab surrounding the finger hole and the portion of the detecting apparatus surrounding the lowermost portion. The resilient force acting on the detecting apparatus to urge it toward its lowermost position is of sufficient force to prevent any upward movement of the detecting device resulting from any upward force resulting from the force applied by the wipe down assembly. However, if the stay-on-tab is mis-located, the lowermost portion of the detecting apparatus will contact a portion of the mis-located tab surrounding the finger hole and the lowermost portion of the detecting apparatus will be move upwardly a distance from its lowermost position. Defects other than a mis-located pull tab can also result in upward movement of the detecting apparatus. The sensing apparatus will sense this upward movement and will generate a signal. The resilient force urging the detecting apparatus into its lowermost position is not of sufficient strength to prevent this upward movement of the detecting apparatus.
REFERENCES:
patent: 5505099 (1996-04-01), Tanaka
Brochure by SPT Stolle Precision Tool Company entitled, “Precision by Craftsmen Serving Worldwide Can Manufacturing Markets”, 7 pages, undated.
Crabtree Harley S.
Curtis Forrest
Nelson Rick W.
Roberts Craig L.
Coors Brewing Company
Fuller Benjamin R.
Klaas, Law, O'Meara & Malkin, P.C.
Malkin Jay K.
O'Meara William P.
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