US3426582A

US3426582A - Cigarette inspection apparatus

Info

Publication number: US3426582A
Application number: US551162A
Authority: US
Inventors: Colin Shaw Mcarthur; Bruce Wall Mcknight
Original assignee: RJ Reynolds Tobacco Co
Current assignee: RJ Reynolds Tobacco Co
Priority date: 1966-05-18
Filing date: 1966-05-18
Publication date: 1969-02-11
Anticipated expiration: 1986-02-11

Description

Feb. 11, 1969 g, s, MEARTHUR AL 3,426,582

CIGARETTE INSPECTIONAPPARATUS Sheet Filed May 18. 1966 DOUBLE LEN TH CIGARETTES SCHM TRIGGER URGE TAN TESTING ZONE SOURQE OF GAS UNDER PRESSURE C lGA RETTE w mm HN N TK R m 0mm 1w mu mmu 1 E A PD VQWW I S NNE w m IIC w m Y B ATTORNEY C. S. MCARTHUR ET AL CIGARETTE INSPECTION APPARATUS Feb.l1,19 69 Sheet 3 Filed May 18, 1966 INVENTOR V COLIN s. McARTHUR BY BRUCE WALL McKNlGHT qiaaa a), (5M

ATTORNEY SOURCE OF 6A5 UNDER PRESSURE Feb. 11, 1969 c. s. M ARTHUR ET AL 3,425,582

CIGARETTE INSPECTION APPARATUS Filed May 18, 1966 Sheet of 4 a ki 22 E 2045 2 5 5 I It. 5

INVEN'T'DR COLlN S, McARTHUR BY BRUCE WALL McKN\GHT ATTQRNEY c. s. M ARTHUR ETA L 3,426,582 CIGARETTE INSPECTION APPARATUS Feb. 11, 1969 Filed May 13, 1966 Sheet 4 or;

TRANSDUCER MEANS U DER PRE SSLRE SOURCE OF GAS UNDER PRESSURE Facyll.

THROTTLE INVENTQRS COLIN s. McARTHuR BRUCE WALL McKNIGHT 07 g M/L ATTORNEY United States Patent 12 Claims ABSTRACT OF THE DISCLOSURE Inspection apparatus for filter cigarettes, in which the interior of the cigarette is subjected to a pressure differing from the external atmospheric pressure, and the internal pressure is utilized to control a bistable fluid amplifier, which in turn actuates an ejecting mechanism if the internal pressure in the cigarette indicates that the cover of the cigarette is leaky. The inspection and ejection of faulty cigarettes takes place at a single station on the periphery of a rotating drum. The peripheral length of that station on the drum surface is substantially equal to the spacing between cigarettes on the drum. The pressure is applied to the cigarette throughout the length of its passage through the station. Synchronizing means is provided so that the ejection apparatus operates only during the latter part of the passage of a cigarette through the station, thereby ensuring that the pressure condition in the cigarette is stabilized before the ejection apparatus is actuated, and also ensuring that only the cigarette under test is ejected if an indication of a leak is found.

This invention relates to the inspection of cigarettes, and more particularly relates to the inspection of cigarettes for imperfections causing air leaks therein.

Sherrill Patent No. 2,951,364 shows an apparatus for inspecting cigarettes for air leaks by passing a flow of air through each cigarette. A mechanical sensing device incorporating a movable member responds to an abnormal air flow, thereby indicating a leak in the particular cigarette under inspection. In response to movement of the movable member, an ejector mechanism is actuated to eject the defective cigarette. Although mechanical sensing arrangements for detecting abnormal air flow conditions have been suitabe in the past, they are slow as compared to the speeds available in present cigarette-making machines and the even greater speeds expected in future machines. It is therefore desirable to have an inspection arrangement for leak detection that can handle cigarettes at the fast rate at which they may now be produced.

It is an object of the present invention to provide an apparatus for the improved inspection of cigarettes for leaks.

Another object of the present invention is to provide for the high speed inspection of cigarettes for leaks.

Another object of the invention is to provide an apparatus for the inspection of cigarettes for leaks employing fluid principles to achieve high speed response of a rejection mechanism to an inspection mechanism.

These and other objects and advantages of the invention will be more apparent as the detailed description of one presently preferred but merely illustrative embodiment of the invention proceeds, with reference to the drawings, in which:

FIG. 1 illustrates an inspection apparatus embodying the invention, having mechanical parts shown in a simplified perspective view and fluid amplifier means parts shown in a simplified diagrammatic vie-w;

FIG. 2 is an end view of a cigarette-conveying apparatus incorporating one form of means for subjecting the cigarettes to a source of gas for inspection for leaks and one form of cigarette rejection means;

FIG. 3 is a side view of the apparatus of FIG. 2;

FIGS. 4, 5, 6, and 7 are sectional views of portions of the apparatus shown in FIG. 3, taken along the section lines 4-4, 55, 6-6, and 7-7 of FIG. 3 and looking in the directions of the corresponding arrows in that figure;

FIG. 8 is a side view of a cigarette-conveying apparatus such as shown in FIG. 3 incorporating a second form of cigarette rejection means responsive to the fluid amplifier means;

FIG. 9 is a sectional view of a portion of the apparatus shown in FIG. 8, taken along section line 9-9 of FIG. 8 and looking in the direction of the arrows;

FIG. 10 is a partial detail view showing a variation on the second form of rejection means; and

FIG. 11 is a simplified view of a second form of means for subjecting the cigarettes to a source of gas for inspection.

As employed herein, the term cigarette is a generic term inclusive of a filter cigarette or a non-filter cigarette, as well as a single length or multiple length cigarette. The term is also intended to include any self-contained smoking article, such as a cigar, which may be tested in accordance with the invention.

Briefly, the present invention provides a leak inspection system wherein gas at an elevated or reduced pressure is applied to each of a succession of cigarettes, and the change in pressure attributable to leaks in the cigarette controls fluid amplifier means so as to divert the output of said means from a first outlet to a second outlet, said second outlet being arranged to actuate means for ejecting the leaky cigarette in question.

The apparatus according to the invention provides very fast response between testing and ejection. This is important because with present day cigarette-making machines approximately 1000 dual cigarettes per minute, or 17 dual cigarettes per second, are handled. This means that the testing and ejection mechanism has to be extremely rapid, e.g. it must test about 17 dual cigarettes per second and reject the leaky ones. Because of this rapid cigarette handling rate, the apparatus must also be extremely reliable, because in even a momentary mechanical break-down a rapid build-up of untested cigarettes or cigarettes which have been incorrectly rejected would occur. The apparatus according to the invention meets the felt need, because, operating upon fluid principles, it is extremely rapid in response and it is extremely reliable, both principally because there is no inertia involved except that of the fluid, which being a gas typically, is extremely low in mass and accordingly in inertia.

Referring to FIG. 1, a conveyor such as a drum assembly 20 is shown carrying a plurality of double length cigarettes 22 thereon, each of which is to be inspected for leaks. Each dual cigarette typically comprises

tobaccofilled portions

22a and 22b at the ends thereof separated by a double length filter section 22c in the middle thereof and fastened together by means of tipping paper and adhesive. Subsequently, each double length cigarette is cut in the middle of filter section 22c to produce two standard filter-type cigarettes. The cigarettes are applied to, carried by, and removed from the drum assembly 20 by means presently to be described. The drum assembly 20 is represented only diagrammatically in FIG. 1; it is shown in more detail in the other figures.

The drum assembly rotates as shown by arrow 24. As each cigarette carried on the drum assembly passes through a testing zone 26, gas (typically air) under constant pressure greater than ambient pressure is applied to the cigarette from a conduit 28. It is possible, but not preferred, to use a constant vacuum system instead of an elevated pressure system. With a vacuum the leak pressure-pulse is positive-going, but with an elevated pressure (as illustrated) it is negative-going. In one form of the invention, the conduit 28 is connected to a source of gas under pressure (not shown) through a regulator 30 and a surge tank 32 to maintain the flow of gas constant. A slip ring arrangement described in detail in connection with FIGS. 2 and 3 couples the conduit 28 to each cigarette as it passes through the testing zone 26.

Gas flows through the cigarette in the testing zone and out of the cigarette and into an outlet conduit 34 connected to a filter 36. The filter filters out any tobacco that may be present in the gas. The gas is then led, by a conduit 38, to fluid amplifier means shown in the lower half of FIG. 1 within the broken line envelope 46. Means 46 operates on fluid amplifier principles, that is to say, the fluid input from conduit 38 controls the fluid output from means 46, so that the output is diverted to a first destination or a second destination, depending upon the level of fluid input pressure at conduit 38. One of the two destinations controls the rejection means for the cigarettes, and the other destination is an exhaust.

The fluid amplifier means 46 comprises a Schmitt trigger 47 responsive to the input of conduit 38 and controlling a pair of NOR gates 50, '54, which in turn control a control flip flop 58. An output flip flop 61 having a greater output than control flip flop 58, is controlled thereby, and either exhausts its output or applies it to conduit 62 which is connected to cigarette rejection means associated with the inspection drum. Fluid power is supplied to fluid arnplifier means 46 from power source conduit P, and in the illustrated embodiment 12.5 p.s.i.g. gas pressure is applied at conduit P.

The Schmitt trigger 47 is a known all-fluid amplifier circuit having the characteristic that the output thereof is switched from its normal output port to the other output port in response to, and for the duration of,

change in a monitored input pressure exceeding a predetermined level. In the circuit of fluid amplifier means 46, Schmitt trigger 47 accordingly acts as a detector which produces a pulse in one of the output ports in response to a pressure signal at conduit 38 exceeding said predetermined level. Schmitt trigger 47 is powered from power source conduit P by a conduit 47a supplying the full 12.5 p.s.i.g. together with a conduit 47b having a fixed restrictor 48 to apply a lower pressure, and a conduit 47c having a variable restrictor 49 to apply a lower variable pressure adapted to set the aforesaid predetermined level.

The output port conduits 47d, 47e of Schmitt trigger 47 are applied respectively to NOR

gates

50, 54. A second control input is applied to NOR

gates

50, 54 by a timing pulse conduit circuit '55, which conduit is connected to power source conduit P through variable restrictor 56 so as to supply an input signal at

branches

55a, 55b to NOR

gates

50, 54 respectively. Conduit 55 includes a side branch 550 which is open ended. An apertured disc assembly 57 is arranged to alternately block and unblock side branch 55c. Apertured disc assembly 57 includes a shaft 57a carrying a disc 57b having a plurality of peripherally located apertures 57c spaced circumferentially on a constant radius. Side branch 55c abuts the circumference traced out by the apertures 57c during rotation of disc 57b with shaft 57a.

As disc 57b is rotated thereby bringing the plurality of apertures 57c successively into coincidence with the open end of side branch 550, the pressure in conduit 55 is repeatedly allowed to exhaust each time an aperture 57c comes into such coincidence. The arrangement is such that the period between adjacent apertures 57c exactly equals the period between consecutive cigarettes 22 reaching the midpoint of testing zone 26. To accomplish this, shaft 57a may actually be the same shaft upon which the inspection drum is mounted, as is illustrated in FIG. 1.

Alternatively shaft 57a can be separate from but driven in exact synchronization with the inspection drum and its shaft, e.g. by gearing. In either case the number of apertures 57c will equal the number of cigarette positions on the inspection drum. It is also possible to employ fewer or more apertures, spaced at greater or lesser angular amounts, provided that the shaft on which disc 57b is mounted is driven at the correct proportion of the speed of the inspecion drum shaft to keep the period between apertures 57c equal to the period between cigarettes 22. In any event, branch 55c is positioned angularly so that the rotation of disc 57b causes a series of negative-going pressure pulses, dropping to zero, corresponding to the coincidence of successive apertures 57c with branch 550, which pulses provide an input at conduit branches 55a 55b to NOR

gates

50, 54 synchronized with the arrival of the respectively associated cigarettes 22 at the mid-point of the testing zone. Power is applied to NOR

gates

50, 54 from conduit 53 which is connected to power source conduit P.

NOR gates are fluid amplifier devices that attain one state when neither of the two input ports receive a pressure signal, and attain another state when either or both input ports do receive a pressure signal. With respect to NOR

gates

50, 54 this means that when a pressure signal is received at either or both of input conduits 47d, 55a of NOR gate 50, the output of that NOR gate will be directed to exhaust port 50a. Similarly, when either or both of input conduits 47c, 55b carries a fluid pressure signal to NOR gate 54, the output of that NOR gate will be directed to exhaust port 54a. On the other hand, when there is no signal on input conduits 47d, 5512, then NOR gate 50 will direct its output to output conduit 50b which forms a first input for control flip flop 58. When no signal appears at input conduits 47e, 551),NOR gate 54 will direct its output to conduit 54b which forms a second input for flip flop '58.

A flip flop is a fluid amplifier device which is bistable, i.e. has an output flow which exists substantially totally in either of two output channels, until positively switched to the other channel by an appropriate input signal. A common example of a fluid amplifier flip flop is the usual bistable fluid amplifier wherein the output flow adheres to the wall of a chamber leading to one output channel until a properly directed input pressure signal snaps it off that wall and across the chamber to lock onto an opposite wall leading to the other output channel.

Flip flops 58, 61 derive their power stream from power source conduit P by conduits 58a, 61a respectively. Conduit 58a is provided with a fixed restrictor 59 to provide a reduced pressure power stream therefor, so that flip flop 61 has a correspondingly greater power output than flip flop 58. The output stream of flip flop 58- is switched into output conduit 58b when the pressure at input conduit 54b exceeds that at input conduit 50b by a predetermined amount. Conversely, the output stream of flip flop 58 is switched into output conduit 580 when the pressure at input conduit 50b exceeds that at input conduit 54b by a predetermined amount. The output stream from flip flop 61 is switched into exhaust port 61b when the input pressure from conduit 58b exceeds the input pressure from conduit 580 by a predetermined amount. Conversely, the output stream of flip flop 61 is switched into output conduit 62 when the input pressure from conduit 58c exceeds the input pressure from conduit 58b by a predetermined amount. As aforesaid, the output conduit 62 leads to the inspection drum where it is connected to the ejection mechanism, so that when an output appears in conduit 62 the leaky cigarette will be ejected.

Viewed at its terminals therefore, fluid amplifier means 46 has a power stream introduced from power conduit P, and this power stream is controlled by the pressure signals arriving at input conduit 38 from cigarettes under test. The testing of a leaky or an acceptable cigarette will be represented by the pressure in input conduit 38 and will,

respectively, cause bistable switching of the power stream derived from power source conduit P into conduit 62 to eject that cigarette, or into exhaust to leave that cigarette as 1s.

The specific means shown in FIG. 1 as an example of fluid amplifier means 46- ac'hieves the aforesaid bistable fluid amplifier terminal characteristics by cooperation of the various circuit elements within fluid amplifier means 46-, as follows. Schmitt trigger 47 discriminates between input pressure signals at conduit 38 which do not meet the aforesaid predetermined level, and those that do. The output of Schmitt trigger 47 is directed to conduit 47d at all times when the signal at input conduit 38 does not meet the aforesaid predetermined level. As soon as the signal at conduit 3 8 meets the aforesaid predetermined level, the output of Schmitt trigger 47 is switched in response thereto from conduit 47d to conduit 47e. By adjustmentof variable restrictor 49, the point at which this switching takes place can be adjusted, i.e. the aforesaid predetermined level can be set. It may be desirable to set the aforesaid predetermined level at any of a range of values depending upon what quality standards as re gards leaky cigarettes the user of the apparatus desires to erect.

The signal at conduit 38 is of course inversely proportional to the leak rate of the cigarette 22 in question, i.e. a higher leak rate at the cigarette 22 produces a lower pressure at conduit 38-. The input signal which causes Schmitt trigger 47 to switch from conduit 47d to 472 is therefore a negative-going pressure Waveform. On the other hand, the signal produced at conduit 47d by Schmitt trigger 47, and switched as aforesaid to channel 47a, is a positive-going pressure signal. That signal is switched to conduit 472 only so long as the input signal which caused the switch appears at conduit 38. The output of Schmitt trigger 47 returns to conduit 47d as soon as that input signal returns above the aforesaid predetermined level, so that conduit 47c receives a pulse of output from Schmitt trigger 47 in response to and for the duration of time that the input signal at conduit 3-8 meets the aforesaid predetermined level. In effect, this means that as long as the leaky cigarette is under test, the Schmitt trigger 47 will direct its output into conduit 47e.

For purposes of the following discussion, reference to the existence of a signal at either of conduits 47d or 472 means that the positive pressure output of Schmitt trigger 47 is present in that particular conduit, and reference to no signal being in either of these output conduits means that the output of Schmitt trigger 47 is present in the other one of these output conduits. Reference to no signal being at conduit branches 55w or 55b means that branch conduit 550 has aligned with one of apertures 57c so that the pressure in conduit 55 has dropped to zero. Conversely, reference to a signal being at either of

conduits

55a or 55b means that branch conduit 550 does not coincide with an aperture 570 and the pressure in conduit 55 is at an elevated value. Hereinafter when no signal is impressed at each of the input conduits to a NOR gate, that will be referred to as no signal-no signal. Similarly, when a signal is applied to one input conduit to a NOR gate and no signal is applied to the other input conduit, that will be referred to as signal-no signal. Finally when a signal is applied to each input conduit of a NOR gate, that will be referred to as signal-signal.

NOR gate 50 constitutes the rejection NOR gate, in that when conduit 50b is energized with the output thereof it triggers the rejection of the leaky cigarette, by changing the state of the flip flops 58, 61 to their rejection state, as will be explained presently. NOR gate 54 constitutes the restoring NOR gate, in that when conduit 54b is energized with the output thereof it restores flip flops 58, 61 to their non-rejection state.

In accordance with the aforesaid rules, a leaky cigarette produces a switch of the output of Schmitt trigger 47 from conduit 47d to conduit 47c, thereby producing a no signalno signal condition at NOR gate 50, and a signal-no signal condition at NOR gate 54. This means that NOR gate 50 must flip to or remain at the output state wherein the rejection output conduit 50b receives the output stream, and the NOR gate 54 must flip to or remain at the condition wherein the exhaust port 54a receives the output stream. Thus conduit 50b is energized and conduit 54b is de-energized, causing the power stream of flip flop 58 to switch into output conduit 580 from output conduit 58]), or to remain at output conduit 580 if it is already there. Flip flop 58, having fluid pressure in output conduit 58c, and an absence of fluid pressure in output conduit 58b, causes flip flop 61 to switch the power stream thereof from exhaust port 61b to the output conduit 62, or to remain at output conduit 62, as the case may be.

Thus the overall rejection sequence in response to a leaky cigarette is that a negative-going pulse at input conduit 38, meeting the aforesaid predetermined level, causes an output flow in conduit 62 which is employed as hereinafter described to reject the very cigarette which caused that flow. It will be remembered that the fluid flow in output conduit 62 is commenced only when the synchronization assembly 57 produces a. pulse indicating that the center of the testing are 26 of the cigarette 22 in question has been reached. It is thus guaranteed that the correct cigarette is ejected in response to the testing measurement. As will be explained hereinbelow, the output flow in conduit 62 persists, due to the bistable nature of flip-flops 58, 61 until the center of the testing zone 26 is reached by the next consecutive cigarette 22, i.e. until the next consecutive aperture 570 coincides with branch conduit 550. At that latter event, the flow in output conduit 62 is either continued (rejecting the new cigarette) or switched into exhaust port 6111 (accepting the new cigarette) depending upon the new input signal at input conduit 38. The output flow in response to any single test is therefore in the form of a pulse whose period is determined by the incidence of successive apertures 57c at branch conduit 55c, i.e. by the period of traverse from the test cigarette being at the mid-point of testing zone 26 to the next successive cigarette being at that mid-point. The pulse period will be multiple if successive cigarettes are leaky, as will appear hereinafter.

The resetting of flip flops 58, 61 so that the power stream of flip flop 61 is switched from output conduit 62 to exhaust port 61b, results when an acceptable cigarette follows a leaky cigarette, as just mentioned. This occurs as follows. As the inspection drum turns so that the next cigarette 22 is brought into the testing zone 26, the apertured disc 57b will also turn so that the open end of branch conduit 550 will move from one aperture 570 to the next. While between apertures, the branch conduit 55c is closed off by disc 57!), so that the pressure in conduit 55 is elevated to yield a signal at

conduit branches

55a, 55b to NOR

gates

50, 54. The presence of a signal during that interval at each of NOR

gates

50, 54 means that each of the NOR gates switches its output flow to its exhaust port. Since flip flops 58, 61 remain locked in their state until positively restored, this action does not affect the rejection state of flip flop 61. However when the next aperture 570 coincides with the open end of branch conduit 55c, no signal is again imposed on each of NOR

gates

50, 54 at the branch conduits 55a, 551) respectively. Assuming that the cigarette: corresponding to this next aperture is not leaky, no signal will appear in conduit 47c applied to NOR gate 54, but the normal signal output of Schmitt trigger 47 will appear in conduit 47a to NOR gate 50. The signal-no signal condition on NOR gate 50 will flip the output thereof from the output conduit 50 h to the exhaust port 50a. The no signal-no signal condition on NOR gate 54 will flip the output thereof from exhaust port 54:! to output conduit: 54b. The presence of fluid pressure in conduit 54b and the absence thereof in conduit 50]; switches the output of flip flop 58 from conduit 580 to conduit 58b. This in turn switches the output of flip flop 61 from rejection output conduit 62 to the exhaust port 61b. The acceptable cigarette following a leaky cigarette thus itself causes the resetting of flip flops 58, 61 so that the rejection flow pulse in conduit 62 ceases, and that cigarette is not rejected.

After the flip flops have been restored to the condition just described wherein there is no output in rejection conduit 62, rejection can be practiced again at the next aperture 57c if the output signal from Schrnitt trigger 47 is switched from its normal output conduit 47d to output conduit 472, as has already been explained. If two or more leaky cigarettes appear consecutively under test, the repeated presence of a signal from Schrnitt trigger 47 to output conduit 478 will mean a repeated no signal-no signal condition on NOR gate 58, and a repeated signal-no signal condition at NOR gate 54. The rejection state of flip flops 58, 61 is thus continued for the second consecutive leaky cigarette. Similarly, if two or more acceptable cigarettes occur in a row the normal output of Schrnitt trigger 47 into conduit 47d will persist, thus repeating a signal-no signal condition at NOR gate 50 and a no signalno signal condition at NOR gate 54. This means that the output of NOR gate 50 will remain at its exhaust port 58a, and the output of NOR gate 54 will remain at its restoring output conduit 54!). The flip flops S8, 61 accordingly will not change from their state wherein the output of flip flop 61 is directed to exhaust port 61b.

The various fluid switching actions just described at the components within fluid amplifier means 46 occur very rapidly, and without the intervention of mechanical moving parts with the exception of disc 57b which may be positively connected to or geared to the inspection drum and is accordingly virtually foolproof. While disc 57b is mechanical, that detracts in no way from the totally fluid principles of the fluid amplifier means 46. This is because the disc 57]; rotates faster or slower together with the inspection drum. It introduces no inertia considerations. The disc 57b is merely a fluid pulse generator whose frequency is controlled by the inspection drum, and need not be mechanical at all. No mechanical element must respond to the fluid pressure signal, i.e. no mechanical element is in the chain of elements responding to the input signal. The system is easily capable of testing and producing a rejection signal or not at the aforesaid 17 dual length cigarettes per second rate,

and moreover is so reliable that production stoppages because of break-downs is virtually non-existent. This is an important advance in an art wherein a number of cigarette-making machines may all be operated at the same time each producing 17 dual length cigarettes per second, or more.

FIGS. 2-7 show in greater detail the construction of a first form of the drum assembly 20 shown in diagrammatic form in FIG. 1. This first form employs valves to eject the rejected cigarettes by the valving on of positive air pressure, the values being turned to the on condition by a pressure switch operated by output conduit 62. In FIG. 2, the drum assembly 20 is adapted to receive a series of cigarettes from a drum assembly 70. The drum assembly 20 rotates clockwise, as shown by arrow 24, while the drum assembly 70 rotates counterclockwise, as shown by arrow 72. The surfaces of the drum assemblies pass tangentially adjacent to each other at a cigarette transfer zone 74, and cigarettes are transferred from the drum assembly 70 to the drum assembly 20, as described in greater detail below. The cigarettes transferred to the drum assembly 20 are thereafter tested as they pass through the testing zone 26 and are either rejected as being defective or are retained on the drum. Those cigarettes retained on the drum are thereafter transferred to a further drum assembly 76 which rotates counterclockwise as shown by arrow 78. Cigarettes are transferred to the drum assembly 76 in transfer zone 80, as described below.

As shown in FIG. 3, the drum assembly 20 comprises a fixed head 82 which serves to mount the drum assembly to a frame (not shown). Journalled within the head 82 is a rotatable drum 84 which extends at one end through the fixed head 82 as a reduced diameter portion 84a. The drum 84 also includes an intermediate stepped portion 841) and an end flange 840. Another fixed head 86 abuts the end flange 840.

The drum 84 carries a plurality of rows of cradles 88 thereon, the rows being arranged around the circumference of the drum upon its outer surface. Each cradle 88 is advantageously concave and semicylindrical so as to cradle a portion of the cylindrical surface of one of the cigarettes 22 carried on the drum. The central pair of cradles 88a in each row receive the cylindrical surface of substantially the entire filter portion 22c of the double length cigarette in the row.

Each cradle 88 has a central orifice 90 opening underneath the cigarette in the cradle. Each of the central elongated cradles 88a has a pair of such orifices. Orifices 90a are also included in the drum 84 in each row of orifices 9']. Internal passageways (not shown) within the drum 84 selectively connect (by appropriate valve action) the orifices 90a to a positive source of gas (typically air) pressure and the orifices 90 to a source of vacuum. Thus each cigarette 22 on the surface of the drum 84 is either ejected from the cradles 88 by positive gas pressure applied to the orifices 90a or retained on the cradles by vacuum applied to orifices 90.

In this regard, the surfaces of the

drum assemblies

78 and 76 are similarly formed with cradles and orifices to retain the cigarettes on or eject the cigarettes from the cradles. In the system of FIG. 2, as each cigarette on the drum 70 enters into the transfer zone 74, it is subjected to a positive gas pressure ejecting that cigarette from the cradles on that drum onto the cradles of the drum 84. At the same time, the orifices 90 in the cradles 88 on the drum 84 within the transfer zone 74 are subjected to a vacuum to receive the cigarette from the drum 70 and to retain the transferred cigarette on the surface of the drum 84. In like fashion, orifices 90a on the drum 84 when in the transfer zone 88 are subjected to positive gas pressure and the orifices in the cradles on the drum 76 are subjected to vacuum to transfer cigarettes from the drum 84 to the drum 76- As shown in FIGS. 3 and 4, the intermediate stepped portion 84b of the drum 84 includes a plurality of holders 92. Each holder is mounted within a corresponding passage 93 and may be reciprocated in the directions indicated by arrow 94 (FIG. 4) by a driving mechanism (not shown) in the drum 84. When a cigarette is transferred from the drum 70 to the drum 84 as described above, the holder 92 on the drum 84 positioned in the transfer zone 74 is in a retracted position within the drum portion 84b. After the cigarette is transferred to the drum 84, the holder 92 is moved outwardly to the position shown in FIGS. 3 and 4 to engage one end of the cigarette 22 transferred to the drum 84. In so engaging the cigarette end, the cigarette is moved slightly to the right with respect to FIG. 3 so that the other end thereof is firmly engaged by surface 96 of the drum flange 840 (FIG. 5).

As shown in FIGS. 3 and 4, each cigarette holder 92 includes a passage 92a therein that communicates with a passage 98 in the drum portion 841:. Similarly, each contact area of the drum flange 840 (FIG. 5) engaging an end of a cigarette communicates with a passage 99 in the drum flange. It will be noted, then, that the

passages

98 and 92a communicate with one end of the cigarette, and the passage 99 communicates with the other end of the cigarette. These passages are provided for subjecting the cigarette to a flow of gas for leak testing as described immediately below.

Gas input conduit 28 is shown in FIG. 3 as mounted on the fixed head 82. FIG. 4 shows that conduit 28 communicates with a passage 100 within the fixed head 82. The passage 100 terminates in a portion 100a that is shown in FIG. 7 as subtending an angle of roughly 25 of rotation of the drum 84. The angular extent of the passage 100a defines the extent of the cigarette testing zone 26. At the other end of the drum 84, as shown at the righthand side of FIG. 3, the gas outlet conduit 34 is connected to the fixed head 86. As shown in FIG. 5, the outlet conduit 34 communicates with a passage 102 in the fixed head. As will be noted from FIG. 6, the passage 102 subtends the same angle as the passage 100a and is located directly opposite the passage 100a.

The

passages

100a and 102 in the fixed heads 82 and 86 are positioned so as to communicate with the

passages

98 and 99 in the drum portions 84b and 840. Hence, during the portion of the revolution of the drum 84 in which the passage 98 leading to a particular cigarette holder 92 communicates with the passage 100a, gas under pressure is provided via the

passages

28 and 98 to that cigarette. The gas flows through the cigarette and into the associated passage 99 in the flange 840 at the other end of the drum, and flows out of that passage into the passage 102 and thence into the outlet conduit 34 to the filter 36 and fluid amplifier means 46 shown in FIG. 1.

Thus as each cigarette passes through the testing zone 26, it is subjected to a flow of gas therethrough. If the cigarettes are all of uniform draft, both the flow of gas and the pressure thereof will be constant. However, if any one of the cigarettes has a leak therein, the gas. flow will leak out, thereby producing the aforesaid negativegoing pressure signal for the duration of testing of that cigarette. In accordance with the presently discussed form of rejection means, the resultant flow in output conduit 62 will actuate relay 68 (FIG. 3), ejecting the leaky cigarette.

With respect to FIG. 2, the angular extent of the testing zone 26 is preferably slightly less than the angular separation of adjacent rows of cradles 88 on the drum 84, so that after each cigarette passes out of the testing zone, there is a short period of time before the next cigarette enters the testing zone. Also, the synchronization pulse from conduit 55 (FIG. 1) occurs at the mid-point of testing zone 26, so that the arm (FIG. 2) is preferably located at the extreme latter end of the movement of the cigarette within the testing zone 26, as illustrated. There is thus provided one-half the zone 26 for the relay 68 to react to eject the leaky cigarette. This is fully ample, even at the contemplated ultra-high cigarette rate, and the mechanical nature of the relay and its switch does not comprise that rate significantly. The angular extent of the testing zone 26 may alternatively be the same as or slightly greater than the angular separation of adjacent rows of cradles 88 on the drum 84. However, the angular extent of the testing zone 26 should not exceed one and one-half times the angular separation of adjacent rows of cradles 88, if the synchronization pulse is to occur one-half the aforesaid angular separation before the position of arm 104.

Referring to FIG. 3, the relay 68 is carried within a housing in arm 104. The relay controls a plunger 68a which, when the relay is energized, may actuate that one of a plurality of valve operators 106 which happens to be passing plunger 68w on the rotating drum portion 84a. The valve operators 106 control the application of vacuum to the orifices 90 and pressure to the orifices 90a so as to cause the cigarettes in the cradles to be retained upon the drum or to be ejected therefrom. Each of the valve operators 106 is associated with a corresponding one of the rows of cradles 88, and is rotatable on its own longitudinal axis. Each valve operator includes a spindle 108 to which are attached a pair of

radial fingers

110 and 112.

The relay housing of arm 104 is so positioned and the relay plunger 68a has an axial movement of suflicient length so as to intercept any finger 112 passing by when the plunger 68a is in its extended position, but adapted to clear any finger 112 passing by when the plunger is in a retracted position. The setting of the valve operators 106 is undisturbed as the drum 84 rotates until an electrical signal to the relay 68 causes the plunger to be extended, as shown in FIG. 3, so as to intercept the finger 112 then in proximity to or next coming into proximity to the plunger 68a, thereby to rotate 90 the valve operator 106. The valving action of the valve operator 106 is such that the 90 turn thereof acts to switch the orifices 90 associated therewith from a normal gas vacuum condition and to apply a positive gas pressure to the associated orifices 90a. This action tends to eject the associated cigarette from the cradles 88.

It will be noted from FIG. 7 that the relay plunger 68a is positioned at the bottom region of the testing zone 26. Hence each cigarette tested in the zone and detected as leaking, thereby causing the relay 68 to be actuated, is ejected from the surface of the drum 84 with gravity assisting air pressure. It should be noted in this connection that each of the cigarette holders 92 is moved to its retracted position after the cigarette has passed through the testing zone 26 so that the associated cigarette may be ejected following the test or may, if found acceptable, be transferred to the drum 76 as explained below.

Referring again to FIG. 2, a finger 120 is fixed to the head 82. The finger is adapted to intercept the finger 110 on any valve operator 106 that is not in the vacuum posi tion. Hence each of the valve operators which has been actuated by the relay plunger 68a to eject its associated cigarette is moved to the vacuum position for proper operation in the next cycle of operation when a cigarette is again received from the drum 70 for testing.

Those cigarettes passing through the testing zone 26 and not ejected from the surface of the drum 84 continue to be retained on the drum until they reach the transfer zone (FIG. 2). In the transfer zone 80, the vacuum supplied to the orifices in the cradles 8 8 is temporarily removed by means of a valving arrangement (not shown) so that the cigarettes may be transferred to the drum 76.

When the form of apparatus including arm 104 and relay 68 is employed, the aforesaid output pulse of air in output conduit 62 is advantageously employed (FIG. 3) to actuate relay 68 to eject the leaky cigarette. In one form, a pneumatic switch 105, preferably of the diaphragm type, is directly actuated (not shown) by the pressure pulse from conduit 62 and thereby closes electrical contacts for the duration of that pulse, connecting electrical power leads 105a to relay 68. In general, fluid back-up pressure is not a problem with the output flip flop 61 of means 46, because the alternative output is exhaust 61b. Therefore, conduit 62 can be connected directly to switch 105. To avoid back-up however, or to employ a higher pressure rated switch 105, which may have better operating characteristics, a pneumatic relay 107 may be employed to receive the pulse from conduit 62 and supply a separate, and stronger, pulse to switch 105 via conduit 107a, as illustrated. Pneumatic relay 107 may be a diaphragm operated needle valve, the diaphragm of which responds to the pressure in conduit 62, and the power circuit of which runs from a pneumatic supply conduit 107b to conduit 107a. The pressure at 107b can be whatever is necessary and suitable. As another alternative (not shown), the pneumatic pressure of pneumatic relay 107 can actuate member 68a via a pneumatic cylinder (not shown) rather than by electrical means, although this is not preferred. Although these various approaches each introduce electrical and mechanical inertia into the rejection system, the improvement contributed by use of fluid amplifier means 46 in detection and pulse generation is so superior that this can be tolerated, especially in adapting pre-existing machines having a relay 68 and valve operators 106 to the present invention. Moreover, the amplification of the leak pulse by means 46 allows faster and more rugged mechanical or electrical rejection means to be employed.

However, the system also can operate with a totally fluid rejection means, thus introducing no mechanical or electrical inertia anywhere, by practicing the alternative form shown in FIGS. 8l0. In that form, the arm 104, relay 68, and valve operators 106 are omitted. The positive pressure orifices 90a are retained, but they are no longer controlled by valve operator 106. Instead, a passage 103 (FIG. 9) appears in fixed head 86, and each row of positive pressure orifices 90a is fed positive pressure by a passage 91, one of which is shown in FIG. 8. Each such passage 91 is located circumferentially midway between the row of orifices 90a to which it is connected and the row immediately in advance thereof on drum 20, i.e., in the direction of rotation of drum. 20. Each passage 91 terminates at an open end 91a abutting, and normally closed by, fixed head 86. Ends 91a are on a common radius with passage 103 in fixed head 86. Passage 103 commences at the circumferential terminal point of passage 102, and continues for about the angular space between adjacent cigarettes 22. Because each passage 91 is one-half that distance in advance of its orifices 90a, the sequencing is such that positive pressure, if applied, commences at the mid-point of testing.

Since ends 91a are normally abutted with head 86, no pressure normally emanates therefrom. But when a passage 91 moves with drum until its end 910 communicates with passage 103, any positive pressure introduced into passage 103 from output conduit 62 will emanate from the line of orifices 90a associated with that particular passage 91. The positive pressure force exerted on the cigarette 22 at orifices 90a can be equal to, greater than, or less than, the vacuum force exerted thereon at orifices 90. If it is greater than the vacuum force, clearly a the cigarette will be ejected. But it will be remembered that there is centrifugal force on each cigarette, and that there is effective gravity force at the bottom portion of drum 20. Consequently in practice a postive pressure force equal to or even somewhat less than, the vacuum force, can also cause ejection of that cigarette. Where a high vacuum is employed, a pressure booster can be employed on conduit 62 to overcome same. This is shown in FIG. 10 where the pneumatic relay 107 already de scribed with reference to FIG. 3 is shown supplying higher pressure to passage 103 in response to a pulse on conduit 62. The positive pressure pulse, from conduit 62 directly or from conduit 107a, can alternatively be applied (not shown) directly to vacuum orifices 90 to negate or substantially negate the vacuum force thereat, rather than being applied to separate orifices 90a as shown.

Relay 107 may be a valve, as mentioned above, and may be actuated by a suitable pressure sensitive transducer means 108, as shown. Transducer means 108 may be a pressure sensitive switch.

As described above, the system of FIGS. 1-10 provides for a flow of gas through each cigarette. The fluid amplifier means 46 monitors the outlet line, and hence requires a filter to remove tobacco from the gas. It may be desirable, however, not to sense dirty gas that has passed through a cigarette, and the alternative embodiments of FIG. 11 are intended to o erate by sensing clean gas prior to its application to the cigarette under test.

Referring to FIG. 11, gas under constant pressure is applied to a branched conduit 122. The common leg 124 of the conduit is connected to input conduit 38 which leads to fluid amplifier 46, while

legs

126 and 128 are coupled to opposite ends of cigarette 22. Depending upon the imperiousness of the cigarette paper to the flow of gas theret-hrough, little or no pressure drop occurs at the comman conduit leg 124 unless there is a leak in the cigarette. When there is a leak however, the negative-going pressure pulse is reflected at the input to the cigarettes at conduit 124, and accordingly is monitored by input conduit 38 to operate means 46 in the same manner as has already been described. The chief difference is that with the arrangement of FIG. 11, which may be practiced with any of the preceding forms of apparatus according to the invention, the gas fed to Schmitt trigger 47 is clean initially, so that a filter is not needed.

What has been described is a fluid amplifier cigarette inspection and rejection system that is very fast, being almost entirely without inertia, very reliable, being entirely or almost entirely Without moving parts or friction, and adaptable to a wide range of inspection rates during operation of a given machine. The bistable nature of the illustrated apparatus is very advantageous in that it divides cigarettes into clearly acceptable and clearly rejected categories depending only upon what side of the arbitrary rejection line they fall, not how far above or below that line they fall. This gives precision to the division, which is advantageous especially in those situations where the accepted cigarettes must be guaranteed to meet a precise minimum fixed standard. Where the division can be rougher, this attribute will weigh less heavily.

The invention has been described with reference to a number of forms, but this was for illustration, not delineation. The illustrative apparatus can be varied in numerous ways within the scope of the invention. All embodiments, illustrated or not, that incorporate the principles of the invention are included within the claimed scope thereof.

What is claimed is:

1. Apparatus for inspecting cigarettes for leaks, comprising:

(a) gas pressure means for subjecting the interior of one of said cigarettes to gas under a pressure different from the pressure outside the cigarette;

(b) monitoring means for monitoring the leakiness of said cigarette as represented by the gas pressure in the interior of said cigarette, comprising fluid amplifier means having a power stream, first and second output channels, and a control input communicating with the gas pressure in the interior of said cigarette and effective to divert said power stream from said first output channel to said second output channel only when said gas pressure is outside a predetermined range;

(c) means responsive to a flow in said second output channel for rejecting said cigarette while it is being tested by said monitoring means;

(d) said gas pressure means including:

(1) conduit means communicating with said cigarette at both ends thereof; and

(2) a source of gas under pressure connected to said conduit means; and

(e) said control input communicates with the gas pressure in said conduit means between said gas pressure source and the ends of said cigarettes.

2. Apparatus for inspecting cigarettes for leaks, comprising:

(a) a testing station;

(b) motive means for moving cigarettes through said testing station sequentially and in a predetermined spaced relation along a normal conveying path, said testing station extending along said path for no more than one and one-half times said predetermined spaced relation;

(0) gas pressure means for subjecting the interior of a cigarette passing through said testing station to gas under a pressure different from the pressure outside the cigarette;

(d) monitoring means for monitoring the leakiness at any cigarette subjected to said gas pressure means in said testing station as represented by the gas pressure in the interior of said cigarette, comprising bistable fiuid amplifier means having a power stream, first and second output channels, and a control input communicating with the gas pressure in the interior of said cigarette and effective to switch said power stream from a stable state in said first output channel to a stable state in said second output channel when said gas pressure is outside of a predetermined range and thereby indicates a leak in the cigarette and;

(e) means responsive to output in said second output channel for ejecting any said cigarette from said normal path before said cigarette leaves said testing station.

3. Cigarette inspecting apparatus according to claim 2, further including means for resetting the output of said fluid amplifier means from said second output channel to said first output channel when the cigarette following a leaky cigarette is not leaky.

4. Cigarette inspecting apparatus according to claim 2, further including synchronizing means allowing said power stream to be switched to said second output channel only after the cigarette under test has reached a predetermined point within said testing station, spaced from the end of the testing station by a distance smaller than the spacing of the cigarettes on said motive means, to ensure that the preceding cigarette has passed beyond the station before the power stream may be so switched.

5. Cigarette inspecting apparatus according to claim 2, wherein said means responsive to output in said second output channel comprises, a passage leading to an orifice under any cigarette in said testing station, said passage being connected to said second output channel.

6. Cigarette inspecting apparatus according to claim 2, wherein said means responsive to output in said second output channel comprises, a passage leading to an orifice under any cigarette in said testing station, a gas pressure source, and means including a normally closed pressure controlled valve connected between said source and said passage, said pressure controlled valve being responsive to the pressure in said second output channel.

7. Apparatus for inspecting cigarettes for leaks, comprising:-

(a) a testing station;

(b) motive means for supplying cigarettes sequential ly to and removing cigarettes sequentially from said testing station in a normal conveying path;

(c) gas pressure means for subjecting the interior of any said cigarette in said testing station to gas under a pressure different from the pressure outside the outside the cigarette in response to movement of that cigarette into said testing station;

(d) monitoring means for monitoring the leakiness of any cigarette subjected to said gas pressure means in said testing station as represented by the air pressure in the interior of said cigarette, comprising a fluid trigger having a control input communicating with the gas pressure in the interior of said cigarette and eifective to switch the output thereof from a normal channel to an alternate channel in response to and for as long as said gas pressure at said control input is outside of a predetermined range and thereby indicates a leak in the cigarette, a fluid pulse generator adapted to generate a pulse each time an entering cigarette reaches a certain point within said testing station, an output flip flop fluid amplifier having first and second output channels and first and second control inputs, and sampling means for sampling said trigger alternate output channel each time said pulse generator produces a pulse and controlling said output flip flop to produce output in said second output channel in response to coexistence of said pulse and output in said alternate channel and until the next said pulse; and

(e) means responsive to output in said output flip flop second output channel for ejecting any said cigarette in said testing station from said normal path to a rejection path.

8. Cigarette inspecting apparatus according to claim 7, wherein said sampling means comprises a control flip flop having the two output channels thereof connected respectively to said first and second output flip flop control inputs, and a pair of NOR gates, one sampling said trigger normal output channel to constitute the rejection NOR gate, and the other sampling said trigger alternate output channel to constitute the restoring NOR gate, each said NOR gate sampling the output of said fluid pulse generator, an alternate output channel of one NOR gate being connected to one control input of said control flip flop, and an alternate output channel of the other NOR gate being connected to the other control input of said control flip flop.

9. Cigarette inspecting apparatus according to claim 7, wherein said fluid pulse generator comprises a source of gas under pressure, a conduit supplied with gas from said source, a restriction in said conduit, and means positively driven in synchronism with movement of said motive means for venting said conduit at a point downstream from said restriction each time said motive means moves so that any cigarette within said testing station reaches a predetermined point therein.

10. Apparatus for testing hollow articles for leaks, comprising:

(a) conveyor means for moving successive holllow articles in a predetermined spaced relation along a normal path through a testing zone having a length in the direction of movement no greater than one and one-half times the spacing between successive articles;

(b) means for connecting the interior of each article in the testing zone to a source of fluid under a pressure having a predetermined difference from the ambient pressure outside said article;

(0) means for sensing the interior pressure of each article as it moves through the testing zone; and

(d) means for ejecting from said normal path each article whose interior pressure is outside of a predetermined range of pressures and thereby indicates a leak in said article;

wherein the improvement comprises:

(e) first bistable fluid amplifier means operatively connected to said ejecting means and shiftable between a normal condition in which it does not actuate the ejecting means and a reject condition in which it does actuate the ejecting means;

(f) second bistable fluid amplifier means in said sensing means to produce a normal output signal only when the interior pressure of an article is within said predetermined range and a contrasting output signal when the interior pressure is outside said range;

(g) means synchronized with said conveyor means for producing a normal output signal except when an article passes a predetermined point in said station, and a contrasting output signal only when an article passes said point; and

(h) third fluid amplifier means responsive only to concurrent contrasting signals from both said signal producing means to switch said first bistable fluid amplifier means to its reject condition.

11. Apparatus as defined in claim 10, including means responsive only to a contrasting signal from said synchronized means concurrently with a normal output signal from said second bistable fluid amplifier means to reset said bistable means to its normal condition.

12. Apparatus for testing cigarettes for leaks, comprising:

(a) conveyor means for moving successive cigarettes in a predetermined spaced relation along a normal path through a testing zone having a length in the direction of movement no greater than one end onehalf times the spacing between successive cigarettes;

(b) means for connecting the interior of each cigarette in the testing zone to a source of fluid under a pressure having a predetermined difference from the ambient pressure outside said cigarette;

(c) means for sensing the interior pressure of each cigarette as it moves through the testing zone;

(d) means selectively operable to eject cigarettes from said normal path to a reject path;

(e) actuating means operatively connected to said ejecting means and shiftable between a normal condition in which it does not actuate the ejecting means and a reject condition in which it actuates the ejecting means;

wherein the improvement comprises:

(f) fluid amplifier means in said sensing means including first and second output conduits, a power supply conduit, and a control input conduit communicating with the interior of said cigarette;

(g) means responsive to the pressure in said control input conduit for controlling the division of flow from said power supply conduit between said output conduits;

(h) means responsive to a predetermined flow in one of said actuating means to its reject condition; and

(i) said operating means being located in said testing Zone and cooperating with said actuating means to eject a defective cigarette from the normal path before the cigarette leaves the testing zone.

References Cited LOUIS R. PRINCE, Primary Examiner.

I. NOLTON, Assistant Examiner.

US. Cl. X.R.

UNITED STATES PATENT OFFICE CER'IIFICATE OF CORRECTION Dated February 11, 1969 Inventor(s)C0lin s. McArthur and Bruce wan McKnight and Col.

Col.

It is certified that error appears in the above-identified patent that said Letters Patent are hereby corrected as shown below:

6, line 9, "inspecitm" should-read inspection 7, line 56, "values" should read .valves 9, line &2, "arm 10' should read arm 10 9, line 89, "comprise" should read compromise 11, line 71, -"imperiousness should read imperviousness 13, line 85, at the end of the line, "outside the" should be deleted.

1, line 2 4, the word "hollow" is misspelled;

1 line 71, "end" should read and 15, l1ne 22, after "said" insert output conduits for operating said SIGNED AND QEALED mum mm! K. .38. Dominican of Disclaimer 3,426,582.U0Zin Shaw IllaArthur and Bruce Wall McKnight, Winston-Salem, N .G. CIGARETTE INSPECTION APPARATUS. Patent dated Feb. 11, 1969. Disclaimer filed July 19, 1972, by the assignee, R. J. Reynolds Tobacco Company. Hereby enters this disclaimer to claims 10 and. 11 of said patent.

[Oficz'al Gazette Febma'ry 1.9, 1.974.]