US3887806A

US3887806A - Faulty can detector

Info

Publication number: US3887806A
Application number: US404784A
Authority: US
Inventors: John J Rodak; Robert L Macheski
Original assignee: Crown Cork and Seal Co Inc
Current assignee: Crown Cork and Seal Co Inc
Priority date: 1973-10-09
Filing date: 1973-10-09
Publication date: 1975-06-03
Anticipated expiration: 1992-06-03

Abstract

A means for detecting abnormal surface conditions on cans, such as burrs and ''''roll back'''' which are caused during trimming and stripping operations. If not detected, these imperfections will cause machine stoppage and production delay. The detector means comprises generally a pivotal actuation means which actuates photocell detectors, in a first embodiment, and electrical sensing means in a second embodiment. Upon detection of a defective can, can production may be halted and the defective can removed or in the alternative, the imperfect can ejected from the production line.

Description

[ 1 June 3, 1975 FAULTY CAN DETECTOR [75] Inventors: John J. Rodak, Southampton;

Robert L. Macheski, Warminster, both of Pa.

{73] Assignee: Crown Cork & Seal Co., Inc.,

Philadelphia, Pa.

221 Filed: Oct. 9, 1973 21 App1.No.:404,784

[52] 0.8. CI. 250/223 B; ZOO/61.41 [51] Int. Cl. H0lj 39/12 [58] Field of Search 250/223 R, 223 B, 231;

ZOO/61.41, 61.42, 153 LA, 153 LB [56] References Cited UNITED STATES PATENTS 2,913,547 11/1959 Zazzara 200161.41 3,017,613 1/1962 Cross ZOO/61.41 3,197,620 7/1965 Peltier 200/6l.4l 3,219,829 11/1965 Reist 250/231 R 3,249,223 5/1966 Johnson 250/223 B 3,301,100 1/1967 Hubeny 200/61.42 3,319,087 5/1967 Wintriss 200/6142 3,363,107 1/1968 Martin 250/231 R 3,433,966 3/1969 Letch 250/223 B 3,588,863 6/1971 Guenther... ZOO/61,41 3,684,845 8/1972 Palmer ZOO/61.41

Primary Examiner-James W. Lawrence Assistant Examiner-D. C. Nelms Attorney, Agent, or Firm-Woodcock, Washburn, Kurtz & Mackiewicz [57] ABSTRACT A means for detecting abnormal surface conditions on cans, such as burrs and roll back" which are caused during trimming and stripping operations. If not detected, these imperfections will cause machine stoppage and production delay. The detector means comprises generally a pivotal actuation means which actuates photocell detectors, in a first embodiment, and electrical sensing means in a second embodiment. Upon detection of a defective can, can production may be halted and the defective can removed or in the alternative, the imperfect can ejected from the production line.

7 Claims, 8 Drawing Figures RELAY 1- "r I 2 11B PUE TER JUFi 3 ms SHEET PNEMEDJUNS SHEET FAULTY (AN DETECTOR BACKGROUND OF THE INVENTION In various can making techniques such as the drawing and ironing of various types of sheet metal. cans may be damaged during a number of operations when mechanisms malfunction. thereby producing cans having surfaces which are cut. bent or otherwise damaged. If such cans are not removed from the production line. they will cause subsequent stoppage of mechanisms as production continues or a defective end product. Several situations are likely to cause conditions which cre ate abnormalities as above mentioned. For example, when a can is formed to the die-pack during production. it must subsequently be stripped therefrom. This is known as mechanical stripping and when the can is being removed. a set of stripper fingers pull it from the punch. Roll back of the can edge which creates a bump or raised area at the edge of the can is caused. Normally during the trimming operation roll back. if it occurs. is not serious since the can portion having the roll back will be trimmed from the can However. when the roll back extends past the can portion that is trimmed. it will cause problems in subsequent operations such as neck flanging and it becomes necessary to remove the defective can from production.

A further detrimental condition is that cans some times have grooves in them from the feeding machinery since they are produced at a tremendous velocity. It is likewise necessary that these cans be removed prior to some of the can production operations to prevent machine stoppage.

Defective cans are also caused by dull trimmers which will cause a burr along the trimmed edge of the can.

SUMMARY OF THE INVENTION It is therefore an object of the subject invention to provide a means of detecting faulty cans at a time during production of the cans to prevent the defective cans from progressing to operations where they will cause stoppage and time delays.

It is another object of the subject invention to provide a detector means for detecting faulty cans which may readily be combined with a step in the can making production so that output is not adversely effected.

It is yet another object of the subject invention to provide a means for detecting faulty cans which while dependable is not so costly as to prevent its use.

It is a further object of the subject invention to provide means for detecting faulty cans in which the means may be adjustable to permit detection of extremely minor abnormalities if such abnormalities will in fact interfere with the production.

In the preferred embodiment ofthe invention. app-a ratus for detecting defective cans comprises means for rotating the can about the longitudinal axis thereof and a detector shoe having a surface positioned in close proximity to the rotating can. A pivot flag member extends from the detector shoe and is pivotally supported at an intermediate pivot point along the length thereof by a support means so as to permit the detector shoe to be deflected through an are substantially tangent to the surface of the can when the detecting portion is deflected by a defect in the can. A sensing means for detecting a defect in the can is actuated by the pivot flag member when the defective portion of the can impacts (ill the detector shoe causing the pivot flag member to pivot.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a front elevational view of the faulty can detection station in which photocell detectors are used and showing a can positioned on the trimmer mandrel while shown in phantom on the turret supply means:

FIG. 2 is a partial side elevational view of the detector station taken along the lines 2-2 of FIG. I and showing the detector shoe and pivotal shaft in alarm position;

FIG. 3 is a top view taken along the lines 33 of FIG. 2;

FIG. 4 is a partial side elevational view similar to FIG. 2, however. an electrical sensing unit is used in place of detectors;

FIG. 5 is a detailed cross-sectional front view of the detector mechanism;

FIG. 6 is a sectional view taken along lines 66 of FIG. 5;

FIG. 7 is a sectional view taken along lines 7-7 of FIG. 5; and

FIG. 8 is an end view taken along lines 8-8 of FIG. 5.

DETAILED DESCRIPTION The faulty or damaged can detector apparatus shown in the above referenced figures comprises generally a detection station having detector means designed to be actuated when the station receives a faulty can having abnormal surface characteristics.

As shown in FIGS. 1 and 2, the detector station It] is positioned adjacent the can production line and may be used in conjunction with apparatus for trimming the cans.

After the cans have been drawn, ironed and stripped from the can dies. they may be fed by means of conveyors to a turret wheel, an individual holder element 14 of which is shown in FIG. I. The turret wheel feeds the cans to the trimming and detection station whereupon as each can in turn reaches a position adjacent the trimming mandrel 16, as shown by can 18 illustrated in phantom, it is horizontally forced laterally in a direction parallel to the can longitudinal axis by the plunger 20 of an air cylinder onto the mandrel 16 which rotates but is otherwise stationary. The air cylinder plunger 20 in this step moves to the left as shown by the arrow and impacts against the can bottom 22 to drive it onto man drel I6. The turret wheel holder element 14 comprises a partial half-cylinder type base 24 configured to receive the cans and since a can is otherwise unrestrained when on the base 24, it may be unobstructedly pushed onto mandrel I6 by the air cylinder. Once the can 18 is so positioned as shown. the trimming and detection operations commence as will be described below.

The trimmer comprises a blade 26 located below the mandrel [6 which is adjusted to trim the can 18 as mandrel and can are subsequently rotatedv The mandrel 16 has

areas

28 and 30 conforming to the inner diameter of the can 18 and thus serve to precisely establish the can position. Mandrel area 30 forms a work rest portion 29 with a slanted periphery which corresponds to the slanted base of the cans. Plunger 20 drives the can I8 against the rotatable work rest portion 29 and the tightness will cause the can to spin as the mandrel rotalesv The detector apparatus is positioned above the mandrel l6 and comprises a detector portion or shoe 32 placed in such close proximity to a can I8 on the man drel 16 that upon rotation of an abnormal can. any raised surfaces of the can will impact against the lower detector shoe surface 34. causing movement a deflection of the detector shoe 32 to the right as shown in phantom in FIG. 2 along a path substantially tangential to the surface of the can. A vertical indicating arm or pivot flag member 36 extends upwardly from the detector shoe 32 and extends through pivotal mount which comprises a pivot block 38 which is secured to a base member 40 by means of a pivot pin 42. The base member is in turn mounted to support structure 44 adjacent the detection station 10. At the top or indicating arm of the vertical pivot flag 36, one of several types of sensing means which will be described is positioned and secured by mounting means.

In more detail. the detector shoe 32 comprises a block-like structure. the base 34 of which has face 46 to permit a can even with an abnormal surface to he slid onto the mandrel 16. The pivot flag 36 is inserted within the detector shoe 32 and secured by means of a spring pin 48. (see FIG. 5) Directly above the detector shoe 32 is a compression spring 50 circumferentially mounted around a support arm of a pivot flag 36 and extending between the detector shoe 32 and the pivot block 38. The pivot flag 36 has secured to a threaded portion 52 thereof. jam nuts 54 which are used to es tabish the height of detector shoe 32. While the threaded portion 52 of pivot flag 36 may extend dowm wardly into the cylindrical bore 56 of pivot block 38, this bore 56 is not threaded (see FIG. 5). thus permitting relative movement of the pivot flag 36 within pivot block 38. The need for this movement can be understood from the following discussion.

When a can is mechanically stripped from a forming die pack by stripper fingers. roll back" which is a bump around its open top end often results. Subsequently, the can is trimmed. as described above and the edge where the roll back is found is usually trimmed away. It is the purpose of the detector apparatus herein disclosed to create an alarm condition when the roll back extends to the untrimmed portion of the can.

The detector shoe lower surface is set close enough to the mandrel 16 to detect, during rotation of the can during the detection period. any amount greater than one can thickness of metal. For the can to be placed on the mandrel with the can portion 58 to be trimmed be yond the detector shoe bottom surface 34, it is necessary that the can be slid under the surface 34. The oncoming can with a roll back portion will impact against slanted face 46 ofthe detector shoe ifthe roll back portion is facing upwardly. The pivot flag 36 will be driven upwardly as permitted by compression spring 50 perniitting the can regardless of its condition to slide under detector shoe 32. lfthe roll back is in the portion of the can to be trimmed. it will pass the detector shoe 32 at which time the shoe will be returned to its set position with the aid of the bias provided by the spring 50.

Extending along a side wall of the pivot flag 36 is a notch 58 into which an alignment keeper member 60 extends. The keeper 60 is secured to the pivot block 38 by screw means 62 (see FIG. 5 l. The pivot block 38 is secured to the major horizontal pivot pin 42 by a spring pin 64 and thus pivot block and pivot pin are joined to be pivotal in unison.

With reference to FIGS. 5 and 6. it will be seen that spring pin 66 extends between the pivot block 38 and base member 40. The spring pin 66 is firmly secured in a tight pin aperture in the base member 40 and is slidably received by an inclined notch portion 68 of pivot block 38 thus enabling pivot action of pivot block 38 which causes the partial rotation of pivot pin 42. This rotation is permitted since the pivot pin 42 is rotatably secured by bushings 70 within the base member 40. FIG. 6 shows the pivot block 38 in its upright position as shown in solid lines and in a pivoted position as shown by phantom lines as it pivots about spring pin 66 while pivot pin 42 rotates also since it is rigidly secured to block 38 by spring pin 64 although this pin 64 is only shown in one position in FIG. 6.

As further shown in FIG. 5. the pivot pin 42 has a grooved portion 72 which accommodates a dowel pin 74 inserted through the base member 40. As shown in FIG. 7, the dowel pin 74 bears close to the reduced diameter cross section portion 76, the section being taken at the grooved portion 72. The dowel pin 74 serves to stabilize pivot pin 42 longitudinally so that it is in a fixed relationship longitudinally with base member 40. The pivot pin 42 remains free to rotate. however. with pivot block 38 as far as permitted by the pinslot 66. 68 configuration illustrated in FIG. 6.

The pivot pin 42 terminates at its left extreme. as shown in FIG. 5. having bifurcated legs 76. 78 with a slot 80 therebetween. A torsion spring 82 is wrapped around legs 76. 78 and secured by screw means 84 to the base element 40. The spring 82 terminates at its left end in across piece 86 which is inserted within slot 80. The torsion spring 82 serves to bias or hold the detector flag 36 in an upright position by torsion-ally holding the pivot block 38 by means of the pivot pin 42 until the detector is engaged by a faulty can which will be described subsequently.

As mentioned previously. the base member 40 is secured to vertical mounting structure 44 and this is done by means of bolts 88. (see FIGS. 2 and 3) A vertical upright 90 has

lower flanges

92 and 94 which permit it to be mounted to base member 40 by means of bolts 96. Mounting bars 98 and 100 are secured to upright 90 by bolts 102. The mounting bars 98 and I00 support a sensing means which may be a photocell setup having a light receiving member 104 attached to a light receiving mount 100 and a light source member 106 attached to the light source mount 98. The photocell elements are connected to a relay for signalling an alarm condition when the pivot flag 36 no longer prevents light from element 106 from reaching element I04. In the alternative. the photocell elements 104 and I06 may be offset from the pivot flag 36 in its inactuated position so that when the pivot flag 36 shifts the light beam will be interrupted to cause the alarm condition.

In operation. when a can 18 is fed by the turret to the position adjacent the mandrel 16. air cylinder 20 will impact against the can bottom 22 driving it onto the mandrel 16. In this position. the can I8 is on the mandrel 16 with the can bottom 22 against the work rest 29 which is also air loaded. This positions the can 18 for the trimming step. As the can 18 is fed onto the mandrel 16. if it impacts against the surface 46 of the detector shoe. the bias of the compression spring will be overcome causing the detector shoe 32 and the pivot flag 36 to be raised somewhat. This is vertical movement only. however. and since the can is not rotating.

the detector means will not he pivoted. When the can 18 is fully positioned on the mandrel l6 and the work rest 29 impacts against the inside bottom can contour. the can 18 will be rotated as the work rest 29 is rotated causing the cut to be made by the trimmer 26. During the rotation ofthe can. if roll back. cut notch portions. or burring is present on the can surface which is rotating below the detector shoe, it will impact or bear against the detector shoe 32 causing the shoe to swivel toward or away from the reader as viewed in FIG. 1 depending on which way the mandrel is rotating. This is shown to be clockwise as seen from the direction shown in FIG. 2. As this happens. the pivot flag 36 piv' ots as permitted by pivot block 38 and the upper extremity of the pivot flag will pass from between the

photocell units

104, 106, thus creating an alarm condition. The dimensions can be such that a 2:1 ratio may be used to cause the upper extremity of the pivot flag 36 to pivot twice that of the detector shoe member 32. The horizontal pivot pin 42 permits the pivot block 38 to pivot to the extent allowed by the pin-

slot

66, 68 combination shown in FIG. 6. The torsion spring 82 will cause the pivot block 38 to assume its normal posi tion after the faulty can has been removedv If a bad can is detected. the sensing means can cause the machine to be shut off immediately in which case. the operator will be required to physically remove the can before further operation. In the alternative the can can be ejected from the mandrel in the normal manner and in the succeeding turret station be expelled automatically from the production line.

Once the trimming cut on the can has been made by trimmer blade 26 and the detection operation has taken place, the air cylinder of the work rest 29 co]- lapses approximately 3/16 of an inch and the piece of can just trimmed passes through a knurled sector having a lower sector which comes through and splits the cut strip and knurls it out into a straight strip. The straight strip is then ejected into an ejection channel which might also accommodate faulty cans when they are ejected automatically if this be the case. At this point. the mandrel air cylinder will drive the can back on the turret and the can production operation will continue.

As shown in FIG. 4, an electrical sensing unit may be used in place of the photocell sensing means. The electrical means may comprise a spring steel pressure member 108 secured to a mounting bar 110 in such a manner so that when the detector shoe 32 and pivot flag 36 are pivoted. the upper extremity of the pivot flag 36 will impact against the spring steel 108 which will then be connected to a low voltage conductor with the relay creating an alarm condition.

In the case of the spring steel sensing means of FIG. 4, an electronic relay of Machinery Electrification Inc. designated as Catalog MEK 54-AA1U-AB may be used along with NEMA 1 enclosure. Catalog MEK i4044-A.

In the case of the photocell device of FIGv l, a TRB chassis with the block-end model TR-4 with a standrad wrap-around cover having light source-TLS-Z and photocell'lPC 4L made by Farmer Electric Products Company. Inc. may be used.

While various embodiments of the invention have been shown and described. it will be understood that various modifications may be made. The appended claims are. therefore. intended to define the true scope of the invention.

What is claimed is:

l. Faulty can detector apparatus for detecting roll back and other defective can conditions comprising:

means for rotating the can about the longitudinal axis thereof;

a detector shoe having a surface positioned in close proximity to the rotating can;

a pivot flag member extending from said detector shoe;

support means to pivotally secure said pivot flag at an intermediate pivot point along its length so as to permit said detector shoe to be deflected through an are substantially tangent to the surface of the can when the detector shoe is deflected by a defect in the can; and

a sensing means for detecting defective can conditions actuatable by said pivot flag member when the defective portion of the can impacts the detector shoe thus causing the pivot flag member to pivot about said intermediate pivot point.

2. The detector apparatus of claim wherein the length of said pivot flag member from said detector shoe to said pivot point is less than the length of said pivot flag member from said pivot point to the extremity of the pivot flag member removed from said detector shoe, said extremity actuating said sensing means. thereby amplifying any deflection of said detector shoe.

3. The apparatus of claim 1 wherein said support means is vertically aligned with said detector shoe when said detector shoe is in an undcflected position of tangency with the can.

4. The apparatus of claim 3 wherein said support means comprises bias means for returning said detector shoe to a position of vertical alignment with said support means after deflection by a defect in a can.

5. The apparatus of claim I further comprising triniming means juxtaposed to said means for rotating the can. said trimming means being located in a position near one end of the can. said detector shoe being spaced from said one end further than said trimming means.

6. The apparatus of claim 3 further comprising resilient means associated with said detector shoe for per mitting vertical movement of said detector shoe at the time the can is mounted on the means for rotating the can.

7. The apparatus of claim 1 wherein the pivot flag member comprises means for adjusting the length thereof so as to adjust sensitivity of the detector shoe by changing the position of the detector shoe with respect to the can.

l l l

Claims

1. Faulty can detector apparatus for detecting roll back and other defective can conditions comprising: means for rotating the can about the longitudinal axis thereof; a detector shoe having a surface positioned in close proximity to the rotating can; a pivot flag member extending from said detector shoe; support means to pivotally secure said pivot flag at an intermediate pivot point along its length so as to permit said detector shoe to be deflected through an arc substantially tangent to the surface of the can when the detector shoe is deflected by a defect in the can; and a sensing means for detecting defective can conditions actuatable by said pivot flag member when the defective portion of the can impacts the detector shoe thus causing the pivot flag member to pivot about said intermediate pivot point.

2. The detector apparatus of claim 1 wherein the length of said pivot flag member from said detector shoe to said pivot point is less than the length of said pivot flag member from said pivot point to the extremity of the pivot flag member removed from said detector shoe, said extremity actuating said sensing means, thereby amplifying any deflection of said detector shoe.

3. The apparatus of claim 1 wherein said support means is vertically aligned with said detector shoe when said detector shoe is in an undeflected position of tangency with the can.

5. The apparatus of claim 1 further comprising trimming means juxtaposed to said means for rotating the can, said trimming means being located in a position near one end of the can, said detector shoe being spaced from said one end further than said trimming means.

6. The apparatus of claim 3 further comprising resilient means associated with said detector shoe for permitting vertical movement of said detector shoe at the time the can is mounted on the means for rotating the can.