US 3382965 A
Description (OCR text may contain errors)
3,382,965 SPACING', AND LES J. PIERCE. JR.. EVICES FOR CONVE ET AL YING TIMING BEVEL-WALLED RECEP'IAC May 14, 1968 I c.
' METHOD OF AND D Filed Dec. 21, 1966.
10 Sheets-Sheet l INVENTORS. Cbeszer J. Pierce, Jr.
Lawrence J. Pagenoarm l M ATTORNEY May 14, 1968 C. J. PIERCE, JR.. ET 3,332,955
METHOD OF AND DEVICES FOR: CONVEYING, SPACING, AND
TIMING BEVEL-WALLED RECEPTACLES Filed Dec. 21, 1966 l0 Sheets-Sheet 2 INVENTORS.
Chester 1 Pierce, J'r. Lawrence J Page/Warm M ATTORA/[Y y 14, 1968 c. J. PIERCE, JR. ET AL 3,382,965
METHOD OF AND DEVICES FOR CONVEYING, SPACING, AND
TIMING BEVEL-WALLED RECEPTACLES Filed Dec. 21, 1966 10 Sheets-Sheet 3 IN VEN TORS Chesfer JFP/erce J).
BY Lawrence J Pagendarm M ATTORNL'Y May 14, 1968 c, J l c JR" ET AL 3,382,965
METHOD OF AND DEVICES FOR CONVEYING, SPACING, AND TIMING BEVEL-WALLED RECEP'IACLES Flled Dec 21 1966 10 Sheets-Sheet 4 v INVENTORS. 'Chesfer Z P/erce, Jr.
flwrenca J Pagenaarm M ATTORNEY C. J. PIERCE, JR. ET AL METHOD OF AND DEVICES FOR CONVEYING,
3,382,965 AND May 14, 1963 SPACING TIMING BEVEL-WALLED RECEPTACLES 1O Sheets-Sheet Filed Dec. 21, 1966 INVENTORS. Chester J. Pierce, Jli By Lawrence J Pagendarm ATTORNEY May 14, 1968 c. J. PIERCE, JR.. ET 3,382,965
METHOD OF AND DEVICES FOR CONVEYING, SPACING, AND TIMING BEVEL-WALLED RECEPTACLES Filed Dec. 21, 1966 10 Sheets-Sheet 6 v INVENTORS. Chesfer 1 Pierce, Jr. Lawrence J Pagenaarm f'v-w-M W m ATTORNEY May 14, 1968 c, c JR" ET AL 3,382,965
METHOD OF AND DEVICES FOR CONVEYING, SPACING, AND TIMING BEVEL-WALLED RECEPTAGLES Filed Dec. 21, 1966 10 Sheets-Sheet 7 IN VEN TORS Chester J." Pierce, J'r. v Zwrenc'e J pagenaarm v ATTORNEY May 14, 1968 c. J. PRERCE, JR.. ET 3,
METHOD OF AND DEVICES FOR CONVEYING, SPACING, AND TIMING BEVEL-WALLED RECEPTACLES Filed Dec. 21, 1966 10 Sheets-Sheet s I N VEN T 0R5 Chesfer 0T P/krce, J72 Lawrence J. Pagendarm M ATTORNEY y 14, 1968 c. J. PlERCE, JR.. ET AL 3,382,9
METHOD OF AND DEVICES FOR CONVEYING, SPACING, AND
, TIMING BEVEL-WALLED RECEPTACLES Filed Dec. 21, 1966 10 Sheets-Sheet 9 Fig. 9
INVENTORS. Chesfer J: P/Zrce, Jr.
' Lawrence (Z Pagendarm PM W (L-u; ATTORNEY M y .4, 1968 c. J. PIERCE, 1a.. 51' AL 3,382, 65
METHOD OF AND DEVICES. FOR CONVEYING, SPACING. AND
TIMING BEVEIJWALLED RECEPTACLES FiledDec. 21, 1966 10 Sheets-Sheet 10 INVENTORS. Che-sler 1 Pierce, Jr; Lpwrence I Pagendarm ATTORNEY United States Patent 3 382,965 METHOD OF AND DEVICES FOR CONVEY- ING, SPACING, AND TIMING BEVEL-WALLED RECEPTACLES Chester J. Pierce, Jr., Palo Alto, and Lawrence J.
Pagendarm, Redwood City, Calif., assignors to Kliklok Corporation, New York, N.Y., a corporation of Delaware Filed Dec. 21, 1966, Ser. No. 603,488 7 Claims. (Cl. 198-34) ABSTRACT OF THE DISCLOSURE The present improvements deal with the problem of articles with tapered sides overriding moving indexing lugs against which the articles are pressed by a conveyor which frictionally engages the articles. The frictional engagement is progressively reduced as the articles assume tilt with respect to the supporting surface of the conveyor, for example by transferring a portion of the article weight to an element which moves no faster than the indexing lug.
In the packaging art, more particularly in the art of packaging foods in folding boxes, it is often necessary to convey receptacles, such as trays, dishes, or pie plates from one station, at which the receptacles arrive in irregular order, to another station at which each receptacle is inserted by automatic machinery into a folding box. During insertion the box advances on a box conveyor which supplies the boxes accurately spaced in timed sequence.
In order to fill each and every box without failure, it is necessary to supply the receptacles equally accurately spaced and timed.
For this purpose it is the present practice to convey the receptacles on a transport conveyor on whose surface they rest and onto which they were released by a suitable escape mechanism which periodically releases one receptacle at a time.
As the receptacle is moved along by the conveyor merely by friction and because of unavoidable minor variations in the timing of the moment of release, the spacing of the receptacles on the conveyor is only approximate, but not sufiiciently accurate.
It is known, for the purpose of improving the accuracy of spacing and timing, to intercept the receptacles by lugs of a further conveyor which moves at a somewhat slower linear rate than the first conveyor. The receptacles run into the aforesaid lugs, whereafter the second conveyor controls the rate of advance of the receptacles and also controls their spacing, which is equal to the spacing of the lugs. As the second conveyor moves less rapidly than the first, the receptacles thereafter slide on the surface of the first conveyor and the frictional force between receptacle and conveyor surface keeps the receptacle pressed against the lug.
Difiiculties are experienced with receptacles comprising tapered walls against which the lug bears. Examples of such receptacles are rimmed or rimless trays or dishes as are used for prepared dinners and pies. These receptacles tend to climb up and override the lugs by reason of the frictional force acting on them and by reason of the taper of the wall which facilitates uptilting and climbing of the receptacles.
For certain reasons the lugs are generally constructed to be retractable or collapsible if acted upon by a force which exceeds a biasing force applied to keep the lugs extended. Such structural details are necessary, for example in order to prevent a lug from upsetting a receptacle on the transport conveyor in the event the lug rises 3,382,965 Patented May 14, 1968 into operative position under a receptacle on the transport conveyor. In such a case the lug is allowed to collapse to let the receptacle pass. It then rises behind the receptacle and intercepts the next one.
If now a receptacle is permitted to climb up on a lug, the lug is also in danger of collapsing and, as a result, an undesired receptacle is passed on to the filling station at which then a jam or misloading occurs necessitating shut down of the entire packaging line.
The invention proceeds from the recognition that the cause of climbing of receptacles is the frictional engagement between the receptacles and the transport conveyor, that uptilting of the receptacles is a danger signal and that it may be utilized to control or reduce the frictional advancing force in such a manner that the force is progressively reduced for increasing tilt of the receptacle with respect to the level of the transport conveyor.
This may be accomplished in various ways. One of the simplest ways of reducing the frictional advancing force is to make the receptacle lighter, so to speak. The basis for this procedure is the fact that the advancing drive force is proportional to the coefficient of friction multiplied by the weight of the receptacle acting on the transport conveyor.
Making the receptacle lighter is most conveniently accomplished by transferring a portion of its weight onto an element other than the transport conveyor. This could be a stationary element, such as a rail, but is preferably an element advancing at the same linear rate as the second conveyor.
The entire weight reduction step of the method is self controlling. The greater the frictional force, the greater the inclination which the receptacle experiences. The greater the inclination the greater the transfer of weight (or loss of weight) which, in turn, amounts to a corresponding reduction of the frictional force. Thus the receptacle ceases to climb and overriding is prevented.
The objects, features, and advantages of this invention will appear more fully from the detailed description which follows accompanied by drawings showing, for the purpose of illustration, a preferred embodiment of the invention. The invention also resides in certain new and original features of construction and combination of elements, as well as steps and combination of steps hereinafter set forth and claimed.
Although the characteristic features of this invention which are .believed to be novel will be particularly pointed out in the claims appended hereto, the invention itself, its objects and advantages, and the manner in which it may be carried out, may be better understood by referring to the following description .taken in connection with the accompanying drawings forming a part of it in which:
FIGS. 1 to 5 are perspective views of the progressive advance of receptacles on a conveying device incorporating the present invention;
FIG. 6 is a perspective view of a normal engagement of a receptacle with the intercepting lug of a timing conveyor;
FIG. 7 is a perspective view of an abnormal condition, the receptacle climbing upon on the lug;
FIG. 8 shows the result of the condition of FIG. 7 as it would occur without application of the invention, the receptacle overriding the lug which collapsed;
FIG. 9 is a perspective end view illustrating the operation of the weight or friction drive reduction resulting from the invention;
FIG. 10 is an elevational view of an escapement element of the device; and
FIG. 11 is a side view, partially diagrammatic, of a particular disposition of an article on the conveying mechanism.
In the following description and in the claims various details will be identified by specific names for convenience. The names, however, are intended to be generic in their application. Corresponding reference characters refer to corresponding parts in the several figures of the drawlngs.
The drawings accompanying, and forming part of, this specification disclose certain specific details of construction for the purpose of explanation of broader aspects of the invention, but it should be understood that structural details may be modified in various respects without departure from the principles of the invention and that the invention may be incorporated in, and its method be practiced by, other structural forms than shown.
Referring to FIG. 1, a transport conveyor comprising chains 11 and 12 moves articles in a direction towards the observer, the article track being laterally defined by lateral rails 13 and 14. The chains 11 and 12 are endless and move at the same linear speed. The upper runs of the chains are substantially horizontal and level and are supported by supporting rails 15 and 16.
Articles are supplied to the far end of the conveyor by any suitable means, for example a roller track which may be slightly downwardly inclined so that articles placed thereon advance toward the conveyor 11, 12 by gravity. The four rollers 17, 18, 19 and 20 at the beginning of the conveyor track may be considered a continuation of a roller track.
Articles arrive at the far end of the conveyor and are then released by an approximate escapement or release mechanism for travel on the conveyor chains 11 and 12 which propel the articles merely by reason of the frictional contact between the chains and the articles.
The escapement or release mechanism comprises a pair of arms extending in opposite directions and mounted on a shaft 21. Only one arm is visible at 22. A finger 23 is pivotally mounted on the arm at 24 and is under the action of a spring 25 which maintains the finger in an extended position (see also FIG. 10). The finger is deflectable against the action of the spring 25 in the event the arm and finger should rise under an article passing over it. In such a case the finger is downwardly deflected into a position in which it clears the article, so as not to upset it. The deflected position is shown in broken lines in FIG. 10.
The finger is a periodically operating stop for the articles about to enter onto the conveyor chains 11, 12 and controls, by its downward withdrawal, the moment at which articles are released. In the position in which the stop 22, 23 is shown in FIG. 1 it is about to release a first tapered dish 26 to which, for convenience of following the article sequence, a single marker 27 was attached.
In FIG. 2 the first dish is moving toward the observer at the velocity v of the conveyor 11, 12. A second dish bearing a double marker 28 is approaching the rotating stop 22, 23 to be released thereby at about the moment illustrated in FIG. 3.
In FIG. 2 a centrally disposed conveyor chain 29 is seen to rise into the path of the articles just ahead of the first dish. The conveyor 29 carries uniformly spaced lugs 30 which are tiltably mounted at transverse pivots 31.
Rearwardly of each lug a supporting element 32 is mounted on the conveyor. This element 32 may be considered as being associated with the lug 30 ahead of it, as lug and element cooperate in controlling the linear rate of advance of an article engaged thereby, as will be described further below.
The lug 30 is two armed, one end 33 being weighted, the other end 34 acting as a stop and being lighter than the one end. As a result, the lug is biased to extend into the path of articles moving on the conveyor 11, 12 so as to intercept them. The conveyor chain 29 moves at a lower linear velocity than the conveyor, consequently the faster moving articles on conveyor 11, 12 catch up with and abut a lug 30 which then slows the articles and causes them to advance thereafter at a lower velocity designated v-Av. In FIG. 3 the first tapered dish is in abutment with, and under the control of, the lug 30. It then continues to slide on the chains 11, 12 because of the difference in the linear velocities which is Av.
As shown in FIG. 11, the raised stop end 34 extends above the level of the top surface of conveyor chains 11, 12 and is in a position to intercept articles moving on the conveyor 11, 12.
Should by accident a lug 30 rise underneath an article carried on the conveyor 11, 12, the raised end 34 is depressed against the weight bias of the heavy end 33, so that both ends 33 and 34 clear the bottom of the article. The degree of clearance is apparent from the broken outline of the lug which shows the lug depressed.
FIG. 11 also shows that the supporting element 32 clears the level of conveyor 11, 12 by an amount h. This amount is so chosen as to provide sufficient clearance for the articles on the conveyor, but the top edge of element 32 is sufliciently close to the level of the supporting surface of the transport conveyor 11, 12 that articles which assume a tilted position on the conveyor 11, 12 (by reason of their tendency to climb up on the respective raised lug 30, come to rest with their trailing portions on the element 32, whereby a portion of the article weight is transferred onto the conveyor 29. This action, as previously stated, reduces the frictional drive exerted by the conveyor 11, 12 on the article and checks further climbing.
Turning to FIG. 6, a bevel-walled dish is shown in a normal position in which its beveled front bears against the stop end 34 of the lug 30.
Occasionally it happens that the frictionally imparted driving force exerted by the conveyor 11, 12 on the dish is so great as to cause the dish to climb up on the lug, which action is aided by the taper of the article wall. This condition is illustrated in FIG. 7 and briefly thereafter would lead to overriding of the lug by the dish, as is shown in FIG. 8, were it not for the combination of the lug 30 with an associated supporting element 32.
FIG. 9 is a view down the conveyor track at about the level of the conveyor 11, 12. It is apparent that the trailing portion of the dish has dipped low enough to seat on the supporting element 32 which has a forked upper end in order to support the dish at two laterally spaced points. It is also seen that the left portion of the dish was lifted completely off the chain 12 at 38. The dish now rests with its trailing portion on the supporting element 32 which moves at the rate v-Av. The right portion of the dish is still engaged by the chain 11, but its drive is insufficient to force the dish further up the stop into an overriding position.
Ideally the dish should be lifted 011 both chains 11 and 12, so as to be supported only by the lug 30 at its leading portion and by the supporting element 32 at its trailing portions. However, imbalance of the dish contents usually results in a slight lateral slant as shown in FIG. 9.
Returning now to the illustrations of the travel of the articles along the conveyor track, FIG. 3 shows the first dish 26 in engagement with portion 34 of the lug 30 at a moment when the associated supporting element (hidden by the dish) is coming up from below on the rising portion of the chain 29. If the supporting element 32 finds the dish substantially level, not tending to climb up on the lug portion 34, it will clear the bottom of the dish. If, however, the dish is slanted so that its trailing bottom portion dips sufficiently far below the level of the conveyor 11, 12, the supporting element 32 will raise the trailing dish portion to reduce its frictional engagement with the conveyor 11, 12, the degree of lift depending on the degree of tilt of the dish (see also FIG. 11).
FIG. 4 shows the first dish moving out of the picture. The second dish is approaching a lug 30 which is rising ahead of it. A third dish approaches the escape mechanism.
FIG. 5 shows the first and second dishes, accurately spaced and timed, entering pockets of a table top-type conveyor 36 fitted with transverse lugs 37. This conveyor carries the dishes to a station at which the dishes are inserted into cartons.
A third dish has arrived from the right. A space was left vacant between the second and the third dish in order to show the end of the conveyor chain 29.
What is claimed is:
1. In the method of spacing and conveying articles having a tapered front, which method comprises the steps of frictionally conveying the articles at a certain linear velocity on the supporting surface of a transport conveyor and intercepting the articles by spaced lugs of a timing conveyor moving at a linear velocity lower than said certain velocity to retard the articles and maintain them at a spacing equal to the lug spacing, the step of progressively reducing the frictional engagement between said transport conveyor and an article as the respective article assumes an increasingly greater inclination with respect to the surface of said transport conveyor incidental to its tendency to climb up on a lug with its tapered front.
2. In the method of spacing and conveying circular trays comprising a peripherally tapered wall, such as pie plates, which method comprises the steps of frictionally conveying on the supporting surface of a transport conveyor the trays at a certain linear velocity, and intercepting the trays by spaced lugs of a timing conveyor moving at a linear velocity lower than said certain velocity to retard the articles and maintain them at a spacing equal to the lug spacing, the step of relieving a portion of the weight of the respective tray bearing on said transport conveyor, in proportion to the inclination of said respective'tray with respect to the said supporting surface incidental to its tending to climb up on a lug with its tapered wall.
3. The method according to claim 2 in which the weight is relieved by a transfer of a portion thereof into the timing conveyor.
4. In a device for conveying and spacing articles, such as trays or dishes having a tapered front, the device comprising, a pair of first conveyors laterally spaced and driven at the same certain linear rate, said first conveyors comprising a top surface for frictionally supporting articles thereon, and a timing conveyor comprising a plurality of spaced lugs extending between the first pair of conveyors and driven at a lower linear rate to intercept said articles by engagement of said lugs with the tapered front of the respective article, said article tending to climb up on, and override, the respective lug, the improvement which comprises a supporting element on said timing conveyor rearwardly of a lug with which the element is associated, said element being at a level sufiiciently far below the said top surface to clear level articles moving on said first conveyor, but sufiiciently close to said level to engage the trailing portion of an article dipping with its trailing portion below said level incidental to the tilting of the article as it climbs up on the associated lug.
5. A device according to claim 4 in which the lugs are pivotally supported on said timing conveyor with freedom to tilt about a horizontal axis from a raised position in which the lugs intercept articles resting on said first conveyors to a lowered position in which the lugs clear said articles on said first conveyor, and in which means are provided for biasing said lugs towards a raised position within that portion of the timing conveyor in which its lugs move between the article carrying top surfaces of the first conveyors.
6. A device according to claim 4 in which said element has a forked upper article-supporting portion for engaging the article at two laterally spaced points.
7. A device according to claim 4 in which the timing conveyor comprises a rising portion within the zone of engagement by the articles with its lugs so as to cause the said supporting element to raise the trailing portion of an article climbing up on the associated lug.
References Cited UNITED STATES PATENTS 3,263,794 8/1966 Burton 19834 RICHARD E. AEGERTER, Primary Examiner.