US3655027A

US3655027A - Unscrambler for light bulb traying machine

Info

Publication number: US3655027A
Application number: US28831A
Authority: US
Inventors: George Albert Douglas; James C Prokopec
Original assignee: Corning Glass Works
Current assignee: Corning Glass Works
Priority date: 1970-04-15
Filing date: 1970-04-15
Publication date: 1972-04-11
Anticipated expiration: 1989-04-11

Abstract

A photoelectric bridge containing a plurality of photoelectric elements is placed across a plurality of channels formed between adjacent conveyor belts and carrying light bulbs which are to be loaded into apertures in a tray. There must be a light bulb in each channel at the loading end so that each aperture in the tray is filled. The photoelectric bridge detects the speed of the light bulbs in each channel and produces an electric signal whenever the light bulbs are moving at less than a predetermined speed, thereby indicating that that channel is relatively full of bulbs. Upstream of the conveyor, the signal operates a diverter or blocking means to temporarily block bulbs from being fed to that channel, thereby diverting incoming lamp bulbs to the other relatively empty channels in which the bulbs are moving relatively quickly. Improved means are also provided for properly orienting the bulbs in the channels and for removing broken bulbs.

Description

United States Patent Douglas et al.

[54] UNSCRAMBLER FOR LIGHT BULB TRAYING MACHINE [72] Inventors: George Albert Douglas; James C.

- Prokopec, both of Danville, Ky.

[73] Assignee: Corning Glass Works, Corning, N.Y.

[22] Filed: Apr. 15, 1970 [2]] Appl. No.: 28,831

521 u.s.c| ..l98/33AA,22l/i0,198/82 51 Int. Cl ..B65g29/00 5s FieldofSearch ..19s/33 AA, 33 R,40,l67,l65,

[56] g References Cited UNITED STATES PATENTS 2,439,883 4/1948 Brown ..53/142 3,536,180 l0/l970 Dubus 2,945,335 7/1960 Nicolle ..53/l42 [151 3,655,027 1451 Apr. 11, 1972 Primary Examiner-Richard E. Aegerter Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak ABSTRACT A photoelectric bridge containing a plurality of photoelectric elements is placed across a plurality of channels formed between adjacent conveyor belts and carrying light bulbs which are to be loaded into apertures in a tray. There must be a light bulb in each channel at the loading end so that each aperture in the tray is filled. The photoelectric bridge detects the speed of the light bulbs in each channel and produces an electric signal whenever the light bulbs are moving at less than a predetermined speed, thereby indicating that that channel is relatively full of bulbs. Upstream of the conveyor, the signal operates a diverter or blocking means to temporarily block bulbs from being fed to that channel, thereby diverting incoming lamp bulbs to the other relatively empty channels in which the bulbs are moving relatively quickly. Improved means are also provided for properly orienting the bulbs in the channels and for removing broken bulbs.

9 Claims, 16 Drawing Figures PATENTEDAPR 11 I972 SHEET 1 [)F 8 I INVENTORS GEORGE A. DOUGLAS JAMES c. PROKOPEC PATENTEDAPP. 1 1 I972 SHEET 3 OF 8 FIG. 3

PATENTEDAPR n ma SHEET 0F 8 I ii PATENTEDAPR 1 1 m2 SHEET 6 OF 8 W b m w M m HUT-:I 4 u 6 I l FIG. 9

FIG. ll

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to the field of automatic article handling machines and more particularly to automatic lamp bulb traying machines in which bulbs received in a disarranged order from a lamp bulb making machine are unscrambled and arranged in rows on a conveyor so that the bulbs can be uniformly loaded into a tray a row at a time.

Description of the Prior Art This invention is an improvement in an automatic lamp bulb traying machine of the type disclosed in U.S. Pat. No. 2,439,883. In such a prior art machine, rows of lamp bulbs are automatically fed to the tray loading mechanism. It is important that a bulb be present in each row at the tray loading mechanism so that every opening in the lamp bulb tray is filled. Each opening must contain a lamp bulb since, in the following frosting operation, the acid used for frosting is applied by nozzles located under the tray and, if there is no bulb in an opening, the acid will shoot up through the opening and fall upon the outer surfaces of the other bulbs in the tray. As recognized in the above-cited patent, since there was no means provided for keeping the number of bulbs in the rows substantially equal, two persons had to be stationed on either side of the conveyor belts in order to remove bulbs from full rows and place them in the relatively empty rows, thereby attempting to. keep a full supply of bulbs in all rows at the tray loading end of the conveyor. These persons also removed broken bulbs and manually corrected the orientation of any bulbs so that each bulb was positioned neck-down between the parallel conveyor belts.

SUMMARY OF THE INVENTION The primary object of the invention is to provide an im- 7 proved unscrambler for a light bulb traying machine wherein the number of bulbs in each row is maintained substantially equal and also wherein the rows of bulbs being fed to the traying machine are automatically maintained relatively full of bulbs, thereby eliminating the need for persons to stand along side the machine to transfer bulbs from relatively full rows to relatively empty rows.

A more specific object of the invention is to provide photoelectric sensing means for detecting the relative speed of the bulbs in the rows in order to produce a control signal which operates blocking or diverting means for diverting bulbs at the input end from the rows which are relatively full to the rows which are relatively empty, thereby assuring that bulbs will continuously appear in all rows at the tray loading end of the machine.

Still another object of the invention is to provide an automatic traying machine with improved mechanical means for properly orienting the bulbs before they are fed to the tray loading mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the input end of the unscrambler showing the blocking or diverting means;

FIG. 2 is a side view of the mechanism for rejecting broken bulbs;

FIG. 3 is a side view of the machine showing the photoelectric sensing means and the means for transferring the bulbs to trays;

FIG. 4 is a top view ofFIG. 1;

FIG. Sis a top view of FIG. 2;

FIG. 6 is a detailed side view of the diverter means shown in FIG. 1;

FIG. 7 is a cross sectional view taken along line 7-7 in FIG.

FIGS. 8a and 8b are cross sectional views taken along line 8-8 in FIG. 2;

FIG. 9 is a cross sectional view taken along line 9-9 in FIG.

FIG. 10 is a cross sectional view taken along line 10-10 in FIG. 2;

FIG. 11 is a detailed view of a portion of the bulb rejecting mechanism illustrated in FIG. 2;

FIG. 12 is a cross sectional view taken along line 12-12 of FIG. 3 showing the photoelectric bridge;

FIG. 13 is a detailed view of a single photoelectric unit taken along line 13-13 of FIG. 12;

FIG. 14 is a schematic electrical diagram of a portion of the electronic control system; and

FIG. 15 is a block diagram of a portion of the electronic control system.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1-3 illustrate the preferred embodiment of the improved traying machine in three portions with the lamp bulbs entering the machine at FIG. 1 and continuing successively through the portions of the machine illustrated in FIGS. 2 and 3. FIGS. 4 and 5 are top views of FIGS. 1 and 2, respectively. The traying machine of which the present invention is an improvement is of the type disclosed in U.S. Pat. No. 2,439,883, which is expressly incorporated by reference herein.

Before describing the details of the invention, there will be presented a brief description of the flow path of the lamp bulbs and the operations performed thereon with reference to FIGS. 1-5.

A lamp bulb making machine (not shown) discharges lamp bulbs B onto a conveyor belt 10 moving in the direction indicated by arrow 12. The bulbs generally extend across the width of the belt 10 and are completely disarranged. As the bulbs leave conveyor belt 10, they are thrown, by action of rotating roller 14, into a disc assembly 16 rotated in the direction indicated by the arrow 18 by means of a suitable drive mechanism such as an electric motor 20, a chain 22, sprockets 24 and 25, and an axle 26. A spider wheel assembly 28 and another disc assembly 30 cooperate with the disc assembly l6 and. guide plates 29 to place individual lamp bulbs neck down in the-channels 33 formed between a plurality of relatively narrow conveyor belts 32, which are supported by a set of rolls 322 in the vicinity of disc assembly 30 and are driven at the same speed by a set of drive rolls 34 which are keyed to a common shaft 36 and driven by a suitable means, such as an electric motor, in the direction indicated by the arrow 38. The surfaces of the drive belts are very smooth and preferably waxed so that, if a bulb is not blocked, there is sufficient friction between the belt and the bulb so that the bulb moves with the belt at the same speed thereof. However, if something blocks the path of the bulb, the bulb will remain stationary as the belts move beneath it. The bulbs are then moved to a checking station 40 where bulbs having broken neck portions are ejected. The unbroken bulbs are then transferred to another set of conveyor belts 42 which are similar to belts 32 and define channels 44 therebetween. The bulbs are carried beneath a photoelectric bridge 46 and then carried to the output end 48 of the unscrambler where they are removed by the operation of an escapement wheel 50 and a traying wheel 52 to be inserted into the openings of a tray 54 carried by a conveyor (not shown) operating in synchronism with belts 42, escapement wheel 50, and the traying wheel 52, all as described in U.S. Pat. No. 2,439,883. The elements are all driven by the same electric motor 55 via a gear box 56.

A detailed description of the structure and operation of the improved unscrambler portion of the traying machine will now be presented.

The disc assembly 16 is conventional and consists of a plurality of tapered spaced flexible discs 60 which frictionally engage the lamp bulbs being transferred from conveyor belt 10 and carries the bulbs in a clockwise direction towards conveyor belts 32. A feature of the present invention is the spider wheel assembly 28, consisting of a plurality of relatively soft notched wheels 62, one of which is spaced between each pair 5 of the discs 60. The notched wheels are driven by means of a common shaft 64 in the direction indicated by the arrow 66. In the event that a lamp bulb, approaching the spider wheel assembly 28, is being carried sideways on the surface of two of the discs 60, then one of the spider wheels kicks such a bulb back in a counterclockwise direction to give the bulb another opportunity to fall in between two of the discs. Lamp bulbs properly positioned between the discs will pass beneath the spider wheel assembly 28 without being affected thereby, and then will be frictionally engaged by the disc assembly 30. This assembly consists of a plurality of flexible spaced untapered discs 70 driven by a common shaft 68. As shown in FIG. 4, discs 70 are spaced the same distance apart as discs 60 and are in alignment therewith. Each pair of discs 70 frictionally engages a bulb from the corresponding pair of discs 62 and transfers the bulb to a corresponding channel between a pair of the moving conveyor belts 32. Guide plates 72 are positioned between each pair of discs 60 and beneath the space between each corresponding pair of discs 70 to assist in the guiding of the light bulbs into the channels between the belts 32. Guide plates 72 also prevent any bulbs from being retained by the disc assembly 16 beyond the transfer point with the disc assembly 30. The disc assembly 30 also greatly enhances the proper orientation of the bulbs neck down and the channels formed between the belts 32, and is another important feature ofthe invention.

Sometimes two bulbs in the same channel, such as the bulbs 74 and 76, become interlocked or jammed together as illustrated in FIG. 4. In order to separate them, an important feature of this invention provides a pair of kicker wheels 78 and 80 which are driven by individual shafts 82 and 84 in a counterclockwise direction as indicated by the arrows 86 and 88. As shown in FIG. 4, there is one pair of kicker wheels 78 and 80 for each conveying channel. Each wheel contains three moderately flexible spokes which extend downwardly towards the channel so as to engage the enlarged portions of the bulbs 74 and 76. The wheels are so disposed so that the spokes of one wheel are near one side of the channel while the spokes of the other wheel are near the other side of the channel. Furthermore, the wheels are driven at different speeds, for example, one may be driven twice as fast as the other. In such an arrangement, when two bulbs are jammed together, such as bulbs 74 and 76, the action of the spokes on the two sets of wheels is to separate the bulbs, the slower moving wheel tend ing to retard the bulb-which it engages and the faster wheel tending to accelerate the movement of the other bulb in the direction of the moving belts.

Another improvement of this invention is the provision of a pair of upstanding partitions 90 disposed on either side of each conveying channel. These partitions are, in practice, posi tioned along the centers of the belts and function to keep the bulbs in the desired neck-down position by preventing them from falling or turning sideways in the channels. These partitions are supported over the belts by means of supporting

frames

92 and 93 which extend transversely across all the conveyor belts 32.

FIG. 7 is a cross sectional view taken along lines 7-7 in FIG. 2 and shows, in more detail, the manner in which partition support frame 92 supports the partitions 90 over the centers of the belts 32. The support frame 92 is itself supported on the main machine frame side rails 94 and 96. Belt support members 98 are positioned beneath belts 32 in order to prevent the belts from sagging.

The bulbs spaced at varying distances are then carried by the conveyor belts 32 in a neck-down position in the channels to the bulb checking station 40 which functions to remove from the channels bulbs with broken neck portions. As a practical matter, if a bulb is broken, it will break at the narrowed neck portion of the lamp bulb envelope. This function in the prior art was provided by two persons, one standing on either side of the mmachine, who manually remove the broken bulbs. As the bulbs approach the right hand end of the conveyor belts 32, a plurality of kicker wheels 100, mounted on a common shaft 101 and rotating in the direction indicated by arrow 102, kick or accelerate the bulbs toward another disc assembly 104 comprising a plurality of pairs of slitted flexible discs 106 driven by a common shaft 108 in the direction in dicated by arrow 110.

Disposed below each pair of discs 106 is a pair of vertical frame members 112 having supporting rail segments 114, the

top surface of each of which presents a double taper as shown in FIGS. 8a and 8b. Secured at 115 to the underside of each rail segment 114 are thin flexible strip-shaped members 116 which define channels 33a characterized in that they are slightly wider than the narrow portion of the neck of the bulbs but smaller than the outside diameter of the neck at the opening of the bulbs. Slots are provided in members 116 to allow for the passage of vertically extending supports 112. Each bulb is frictionally engaged between two of the discs 106 which tend to rotate the bulb counterclockwise out of the channel 112. As illustrated in FIG. 8a, if the neck 117 of the bulb 118 is intact, then the enlarged end portion 120 is forced upwardly against the lower surface of the members 116 to prevent the bulb from being removed from the channel, in which case the bulb is merely moved to the right to be inserted into one of the channels 44 between the conveyor belts 42. However, as shown in FIG. 8b, if a bulb 122 has a broken-off neck portion, then the discs 106 will remove the bulb from the channel 33a and carry it upwardly counterclockwise and against a guide plate 124 from where it is discharged into a trough 126 containing a continuously rotating screw conveyor. The broken bulbs are conveyed by the screw conveyor to an outlet 128 from which they are ejected.

The assembly carrying the discs 106 is shown in more detail in FIG. 9. For the sake of clarity, only one pair of discs 106 is shown in this Figure. Since different sized bulbs may be handled by this machine, it is necessary to provide some means for adjusting the spacing between each pair of discs 106a and 10611 in order to accommodate different diameter bulbs. The common drive shaft 108 is integral with or fixed to an inner shaft 130 having a threaded end portion 132. Shaft 130 is keyed to an outer hollow shaft 134 by means of keys 136 fixed to shaft 130 and riding in the slot 138 formed in the outer shaft 134. Shaft 134 also has'a threaded end portion 140, but the

end portions

132 and 140 have threads running in opposite directions. An appropriate threaded coupling 141 is threaded onto the

end portions

132 and 140 and is mounted for rotation in a suitable bearing 142. The disc 1060 is fixed to a'collar 144 which receives the portion of keys 136 extending through slots 138 beyond the periphery of shaft 134. In like manner, the disc 1061) is fixed to a collar 148 which is keyed to the outer shaft 134. Consequently, when shaft 108 is rotating,

shafts

130, 134, and the discs 106 rotate with it. Also, when a wrench 150 is applied to the end of the coupling 141 to rotate the coupling, the

shafts

130 and 134 will be driven axially in opposite directions to either increase the separation between the discs or decrease the separation, depending upon the direction of rotation of the coupling 142. Of course, since all the discs 106 are mounted in the same manner as discs 106a and 106b, all the discs are simultaneously adjusted. Furthermore, because of the construction, discs 106a and 106b are maintained equidistant from the center line 152 between the discs. The disc assembly 104 is pivotably mounted on a shaft 154 to enable the disc assembly to be rotated clockwise to give access to the channels 33a below the assembly, if so desired. Shaft 101 of kicker wheel assembly 100, trough 126 and shaft 108 of the disc assembly are supported between

vertical plates

156 and 158 whose opposite ends are fixed to a hollow shaft 160 connected to shaft 154 via a relatively heavy torsion spring 162. When the disc assembly 104 is in the position illustrated in FIG. 2, the torsion spring is wound in such a direction as to counterbalance the weight of the disc assembly. This is accomplished by means of a worm gear 164 fixed to shaft 154. One end 166 of the spring is fixed in a slot in a collar 168 which is fixed to the shaft 154. The other end 170 of the torsion spring is fixed to the hollow shaft 160. Shaft 154 is supported at its ends by

extensions

172 and 174 which are fixed to the machine frame. When the spring is properly wound to counterbalance the weight of the disc assembly, the disc assembly may be manually rotated clockwise without any great effort.

Since the bulbs may also vary in length, it is necessary to provide some means for adjusting the vertical position of the flexible metal slats 116.

The mechanism illustrated in FIG. 11 is a means for accomplishing this result.

A mounting plate 180 is fixed at either end to the machine frames 182 and 184, and a cross member 186 is fixed to the vertical support members 112 which support the V-shaped bulb holding rails 114. These rails are V-shaped for two reasons: 1) to better conform to the curve of the bulb envelope and also 2) to permit any broken glass to fall off the rails. A threaded shaft 187 having a knob 188 on its lower end passes through the mounting plate 180 and the cross member 186 where it is clamped by a nut 190. A yoke 192 is threaded on the threaded portion of the shaft 186. A pair of

lever arms

194 and 196 are pivoted at 198 and 200, respectively, on the yoke 192. Since this adjusting device is symmetrical, we will look at only one side thereof. The arm 194 is pivoted at point 202 to another arm 204 which is fixed to a shaft 206 which extends across the width of the machine. Fixed to the shaft 206 is a plurality of lever arms, such as 208, having a roller 210 mounted on the end thereof. Cooperating with each of the rollers 210, is a U-shaped member 212 whose upper portion 214 engages the lower end of the flexible metal slat 116. There is a Ushaped member 212 and a pair of arms 208 for each of the metal slats. When it is desired to lower or raise the slats 116 to accommodate longer or shorter bulbs, respectively, knob 188 is turned in the appropriate direction to cause the arms 208 to rotate either up or down, to either raise or lower the U-shaped member 212 and thereby raise or lower the slats 116.

A bar 220 extends across the width of the machine in the checking station and is fixed at either end thereof to the

side frame members

156 and 158. This bar supports a plurality of partitions 221 which further assist in keeping the bulbs in proper alignment so that they are accurately fed from the disc assembly 104 into the channels 44 between the conveyor belts 42 as illustrated in FIG. 5. As the bulbs are carried by conveyor belts 42 toward the output end 48 of the machine, the bulbs begin to stack up in the channels, because their motion is temporarily blocked by the action of the escapement wheel 50. Because of this stacking, some bulbs may be pushed or squeezed upwardly out of the channel. In order to prevent this, hold down rails 230 are mounted above the channels 44 formed between the belts 42. These rails are fixed to cross members 232 which in turn are supported by standards 234 mounted on either side of the machine. These standards have adjusting means for adjusting the vertical height of the rails over the bulbs to accommodate different length bulbs. By placing the rails just above the height of the bulbs being processed, bulbs are prevented from jumping out of the channels.

As was mentioned before, the bulbs traveling along the channels in the various conveyor belts are spaced at varying distances because of the random manner in which the bulbs are transferred from the conveyor belt to the additional disc assembly 16. However, it is important that all the channels be filled with bulbs at the output end 48 of the machine so that each hole in each row of the trays contains a bulb before the bulbs are subjected to an acid spraying operation for frosting the interior of the bulbs. Ideally, there should be several bulbs stacked up in each channel at the output end 48 of the machine. Practically, it is desirable to have each row of bulbs stacked up back to the photoelectric bridge 46.

In order to eliminate the necessity for two persons standing on opposite sides of the machine to make sure all channels are filled, an important feature of this invention provides an automatic means for keeping all channels filled with bulbs. As mentioned before, when the paths of the bulbs are not blocked, they travel at the same speed as the conveyor belts 42. However, when they become stacked up because of the blocking action of the escapement wheel 50, the bulbs begin to block the movement of each other and to travel more slowly than the conveyor belts which are carrying them. Consequently, bulbs which are traveling at a relatively high speed, i.e., at the speed of the conveyor belts when they pass under the photoelectric cell bridge 46, indicate that that channel is relatively empty or starved of bulbs. Conversely, when the bulbs traveling underneath the bridge are moving relatively slow, it is an indication that that channel is relatively full of bulbs. As will be described in more detail below, the function of the photoelectric bridge, in conjunction with electronic control circuits illustrated in FIGS. 14 and 15, is to produce a control signal indicative of each slow moving bulb which control signal is then used to divert bulbs away from the disc pairs in disc assembly 16 corresponding to the slow moving channels.

As illustrated in FIG. 12, the photoelectric bridge 46 comprises a support member 240 which is supported by a pair of adjustable mechanisms 242 which in turn are mounted on the side frame members of the machine. Mounted in the member 240, above each channel 44, is a photoelectric unit 244 having a cylindrical shade 246 fixed to the lower end thereof. The bridge may be raised and lowered according to the height of the bulbs in order to assure a strong signal output from the photoelectric units. This adjustment may be accomplished by means, for example, of the screw and bevel gear systems 248 within each of the adjustable mechanisms 242.

As shown in FIG. 13, each photoelectric unit 244 comprises a housing 250 including a lamp 252 and a photocell 254. The bulb 256 is shown passing beneath the aperture 258 in the housing and in the direction indicated by the arrow 260. Light from the lamp 252 impinges upon the top surface of the bulb 256 and is reflected back to the photocell 254 which in turn produces an electrical signal indicating the presence of a bulb. The angles of the photocell and lamp are adjusted to give the strongest signal output.

As will be described in more detail below, the electronic control circuits discriminate between a short photocell signal corresponding to a fast moving bulb and a long photocell signal corresponding to a slow moving bulb. A long signal produces a control signal which in turn operates a solenoid valve 260 in the blocking or diverter assembly shown in FIGS. 1 and 6. The blocking or diverter assembly 262 comprises a plurality of blocking or diverter paddles 264, one for each of the lamp bulb carrying channels in the machine. FIGS. 1 and 6 show the details of a single blocking member or diverter, and FIG. 4 shows all the blocking or diverter mechanisms supported by a plate 266 which is connected to the machine main frame by means of a pair of brackets 268. Looking at a single blocking member or diverter, we see that the paddle 264 is fixed, as by riveting, to a metal disc 270. The disc 270 is rotatably mounted on a pin 272 which is mounted in a pair of brackets 274 fixed to the diverter support frame 276 which in turn is supported by the cross member 266. Support frame 276 also carries an air cylinder 278 which reciprocates a piston rod 280 pivotably connected at 282 to a connector rod 284 which in turn is pivoted at 286 to a lever arm 288 fixed to disc 270.

The full line position of the diverter panddle 264 in FIG. 1 is the normal position of the paddle, i.e., the position for the condition when its corresponding row of bulbs passing under the photoelectric bridge 46 is relatively empty and therefore moving quickly beneath the photoelectric bridge so that no control signal is produced to operate the solenoid valve 260.

When the control signal is produced by the electronic control circuit, indicating that the bulbs are stacked up in the corresponding row beneath the photoelectric bridge and therefore moving relatively slowly, the diverter is moved to its dotted line position where it blocks bulbs from entering between the two discs corresponding to the stacked up channel. Consequently, the bulb is diverted to spaces between other pairs of discs corresponding to rows which are relatively empty and therefore moving relatively quickly beneath the photoelectric bridge. Air under pressure is supplied to the solenoid valve 260 via the inlet 290. Depending upon the position of the solenoid valve, the air is supplied to the cylinder 278 by either a

conduit

292 or 294. When the diverter paddle 264 is in its normal full line position, as illustrated in FIG. 1, the air pressure is applied via the conduit 294 so that the piston rod is forced to the left thereby pivoting the diverter paddle 264 clockwise to the full line position shown. When the control signal is received by the solenoid valve 260, the air is diverted from conduit 294 to conduit 292 to force the piston rod to the right, thereby pivoting the diverter paddle 264 counterclockwise to the dotted line position.

The operation of the diverters by the photoelectric bridge maintains equal the number of bulbs in all the channels approaching the output end 48 of the machine. However, in addition to this transverse loading problem, there is also a longitudinal loading problem, i.e., the distribution of the bulbs along the lengths of the belts 42. If too many of the diverters are energized, this means that the traying machine is running too slowly. If too few of the diverters are energized, this indicates that the traying machine is running too fast. It is obvious that if all of the channels or rows of bulbs are stacked up to a point upstream of the photoelectric bridge 46, then all of the diverters will be out and the rows of bulbs cannot be equalized. Furthermore, if none of the rows of bulbs is stacked back to the photoelectric bridge, then none of the diverters is out and again the rows cannot be equalized. Therefore, it is desirable to have a certain percentage of the rows stacked up to a point upstream of the bridge and the remaining stacked up to a point downstream of the photoelectric bridge. For a 12 row or channel machine, it has been found desirable to have five,

six, or seven diverters operating for optimum equalization of the rows. The electronic circuitry, as will be described below, assures this type of diverter operation by controlling the speed of the traying machine, i.e., the conveyor belts 42, the escapement wheel 50, the traying wheel 52, and the tray conveyor 54 by controlling the speed of the drive motor 56 which drives these components of the traying machine.

FIG. 14 is a schematic diagram of a circuit for generating from the output of each photocell 254 the control signal which operates solenoid valve 260 which in turn operates the diverter paddle 264. There is such a circuit for each of the diverter paddles, but since they are all identical, the circuit for only one diverter paddle is shown in FIG. 14.

Each time a bulb passes under the photoelectric bridge 46, the light reflected from the dome of the bulb impinges upon the photocell 254 which becomes conductive to energize a relay coil 300. In the normal or unenergized condition of relay coil 300, its movable contact 302 is closed to the fixed contact 304. When the relay coil is energized, the movable contact closes to the other fixed contact 306. The contacts of the relay 300 are part of a slow-make, fast-break time delay circuit 308. The length of time that the relay coil is energized is dependent upon the speed of the bulbs passing under the photocell 254. If the bulbs are stacked up to the photoelectric bridge, they pass under the bridge at a slower rate than when they are stacked back to a point downstream of the photoelectric bridge. Since it is desired to operate the diverter paddle only when the bulbs in the corresponding channel are moving slowly, the purpose of circuit 308 is to distinguish between slow moving and fast moving bulbs. It has been found in the typical operation of the machine that a bulb in a full row or channel requires about 100 milliseconds to pass under the photocell, whereas a bulb in a relatively empty channel requires only about 50 milliseconds. Therefore, it is desired to generate a diverter control signal only when the photocell is energized by the reflected light for a period of time in between these two values, say, for example, 75 milliseconds. Therefore, in essence, circuit 308 is designed to provide a delay of 75 milliseconds from the time of energization of the relay coil 300 and the closure of the contact arm 302 to the fixed contact 306. This delay is provided by the adjustable 100K resistor R5.

The circuit also includes a relay coil CR1 whose movable contact is shown in its normal or de-energized position closed to fixed contact 312. When the relay coil 300 is energized, contact 302 closes to contact 306 thereby permitting a capacitor C1 to charge at a rate determined by the value of resistor R5. If the relay coil remains energized sufficiently long for the voltage of capacitor C1 to reach the firing voltage of the unijunction transistor Q1, Q1 then fires and becomes conducting to permit the capacitor C1 to discharge through the emitter and lower base of the unijunction transistor and through the relay coil CR1 to move the contact 310 to the fixed contact 314. Firing of the unijunction transistor 01 indicates that a slow moving bulb has passed under the photocell 254, in this case, a slow moving bulb being one that requires milliseconds or longer to pass under the photocell. Closing of the contact 310 to contact 314 connects the gate of a silicon controlled switch SCSl to the capacitor C1 which applies a positive pulse to the gate, thereby turning the switch SCSl on. A diode D1 across relay coil CR1 shorts out any counter EMF which could result in spurious operation of Q1. The 1K resistor R4 shorts out any residual charge on capacitor C1 through the normally closed

contacts

302, 304 when relay coil 300 is de-energized, thereby eliminating the possibility of timing errors due to an accumulative residual EMF on the capacitor C1. The variable 5K resistor R1 is used to bias the upper base of the unijunction transistor Q1 relative to the lower base and the emitter.

The conduction of the silicon controlled switch SCSl causes a relay coil CR2 to be energized to close its normally open contacts CR2-1 which are connected in series with the solenoid valve 260 controlling the operation of the diverter paddle. Connected in series with these contacts are a pair of contacts CR3-l which are opened and closed periodically in accordance with the pulse rate of a multivibrator 316 which periodically energizes and de-energizes the relay coil CR3. Energization of solenoid 260 raises the diverter paddle to its dotted line position to block bulbs from entering the channel corresponding to the photocells 254. Multivibrator 316 functions to modulate the operation of the diverter, i.e., the diverter is moved back and forth between its full line and dotted line positions as long as contacts CR2-l are closed. This modulation prevents hunting of the system so that a full row does not suddenly become starved of bulbs as might happen if the diverter were left in its dotted line position for the duration of a control signal.

Since the relay coil 300 will be de-energized between each pair of bulbs even though the bulbs are closely stacked together, it is desirable not to have the relay CR2 drop out between bulbs. The delay action to prevent this is provided by the capacitor C2 and another unijunction transistor Q2. When relay coil CR1 is energized, its switch contacts CR1-2 connect capacitor C2 to ground. However, when CR1 is de-energized by the turning off of the unijunction transistor Q1, switch contacts CR1-2 connect the capacitor C2 to the emitter of 02. At a predetermined time, controlled by the variable resistor R9, the capacitor C2 will charge to a voltage sufficient to cause unijunction O2 to conduct, thereby discharging capacitor C2. This drives the anode of SCSI to a negative cutoff value, thereby rendering it non-conductive. At this time, relay CR2 drops out to open its contacts CR2-1 in the diverter control circuit.

FIG. 15 is a block diagram illustrating the manner in which the speed of the traying machine is controlled to compensate for variance in the longitudinal loading of the belts 42. Each of the relay coils CR2 also has another set of normally open contacts CR2-2 which are closed by the energization of the relay coil CR2. These contacts are placed in series with another set of normally open contacts CR3-1 which are closed sequentially during each cycle of a ring counter 320 driven by a suitable pulse generator 322. For example, the ring counter may sequentially energize relay coils corresponding to each of the contacts CR3-l.

All the series combinations of contacts CR2-2 and CR3-l are connected in parallel to the input of a preset counter 324 having three presets. For each cycle of the ring counter 320, the preset counter 324 counts the number of diverter operations as represented by closures of contacts CR2-2. The preset counter 324 is reset on each thirteenth count of the ring counter.

The preset counter has four output lines corresponding to diverter counts of less than five, five, six and seven, respectively. When the counter counts up to counts of five, six and seven, corresponding pairs of contacts are operated, for example, by energization of corresponding relays. Switch contacts 55-1 and 55-2 are associated with a count of five, switch contacts 86-1 and S6-2 with a count of six, and switch contacts 57-1 and 57-2 with a count of seven. The switch contacts are illustrated in their normal position, i.e., the position when the counter is not at the count corresponding to the count associated with the particular set of contacts.

Each of the four preset counter output lines is connected to energize corresponding ones of four

pulse generators

326, 328, 330, and 332.

These pulse generators are connected to a stepping servo motor 334 which drives a speed control potentiometer which controls the speed of the traying machine drive motor 56. The pulse generator 326 is connected to the reverse winding of the servo motor which causes the potentiometer 336 to be adjusted to slow down drive motor 55.

Pulse generators

328, 330, and 332 are all connected to the forward winding of servo motor 334 and have pulse rates of increasing value. In other words, the pulse rate of pulse generator 332 is greater than that of pulse generator 328 and therefore would increase the speed of motor 55 much more quickly.

When the number of closed diverter contacts CR2-2 is less than five during one cycle of the ring counter 320, thereby indicating that less than five diverters are in their blocking positions and also indicating therefore that the traying machine is running faster than desired, the pulse generator 326 is energized through the closed contacts S-1 and S to reduce the speed of the machine. As a result, more rows or channels should have bulbs stacked up to the photoelectric bridge, and therefore eventually five diverters will be operated and the counter 324 will count up to five. In this case, contacts S5-1 open and contacts S5-2 close to permit energization of the pulse generator 328 whose output drives the servo motor in the direction to increase the speed of the drive motor 55. If the number of diverters counted increases to six, then switch contacts 86-] open and switch contacts 56-2 close to energize the higher pulse rate generator 330 to more quickly increase the speed of the drive motor 55. In like manner, if the diverter count reaches seven, switch contacts S7-1 open and switch contacts S7-2 close to energize the highest pulse rate generator 322.

Drive motor 55 also drives a tachometer generator 338 which is connected to a voltmeter 340 calibrated in hundreds of light bulbs being trayed per minute. The tachometer voltage is bucked in a meter relay 340 against a portion of a reference voltage V appearing across a voltage divider 342. The adjustable tap 344 is positioned so that the portion of the reference voltage bucked against the tachometer voltage results in a null or zero reading of the meter relay needle 345. For example, the tap may be set such that the needle reads zero when 1,100 bulbs per minute are being trayed. The meter is calibrated in i hundreds of bulbs relative to this figure of 1,100. The switch contacts 8,, represents a traying speed of 950 bulbs per minute and the switch contacts S represent a traying speed of l,250 bulbs. Consequently, if the traying speed should drop below 950 bulbs per minute, needle 345 opens the contact 8,, tofdisable the pulse generator 326, thereby preventing further decrease in the traying speed. In like manner, if the traying speed should exceed 1,250 bulbs per minute, the switch contacts S are open to disable the fast pulse generator 302, thereby preventing any further increase in the traying speed.

This type of digital proportional control combined with the diverter action maintains equal distribution of the bulbs in all the rows and insures that the loading of the belt is controlled in such a manner that the equalization action of the diverters is effective.

It may happen that some unusual circumstance would require a change in the load set point represented by the position of the adjustable tap 344. For example, the output of the bulb making machine feeding conveyor 10 may either increase or decrease for a period of time. To accommodate this possibility, a servo motor 346 is coupled to the adjustable tap 344. A pulse generator 348 is coupled to the forward terminal 350 of the servo motor, and a pulse generator 351 is connected to the reverse terminal 352 of the servo motor. Each of the

pulse generators

348 and 351 contains a time delay circuit (not shown) of approximately six seconds. When the needle 345 strikes the switch at the high speed point of +1 50 bulbs, it closes the switch contacts S and S, to electrically connect pulse generator 348 to the servo motor 346. However, because of the built'in delay, these switches must be closed for at least six seconds before the servo motor is energized to move the voltage divider tap 344 and thereby change the load set point of the traying machine. In like manner, when the needle 345 strikes the low speed switch at l 50 bulbs, the switch contacts S and S are closed to couple the pulse generator 351 to the servo motor 346; if these switches remain closed for 6 seconds or more, the servo motor 346 moves the adjustable tap 344 to a new load set point and a lower traying speed.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the following claims:

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a light bulb traying machine including unscrambler means for separating a plurality of disarranged light bulbs into individual rows and discharging the bulbs onto conveying means, said conveying means including a plurality of moving belts defining channels therebetween for carrying said bulbs in a neck-down position, the bulbs moving from the input end to the output end of said conveying means, the improvement comprising:

a. photoelectric sensing means between said input and output ends of said conveying means for sensing the speed of individual bulbs moving in each of said channels and for producing a bulb signal proportional to the time required for each bulb to pass said sensing means,

b. blocking means including a plurality of blocking members each associated with a different one of said channels and individually operable to block bulbs from relatively slow moving channels of bulbs so that the bulbs are diverted to relatively fast moving channels of bulbs whereby all channels carry substantially the same number of bulbs, and

c. first electronic control means responsive to bulb signals whose durations exceed a predetermined duration to produce a control signal to operate said blocking means.

2. The improved light bulb unscrambler means as defined in claim 1 further comprising means for continually modulating an operated blocking member between blocking and nonblocking positions.

3. An improved light bulb unscrambler means as defined in claim 1 wherein said photoelectric sensing means comprises a plurality of photoelectric sensing devices equal in number to the number of said channels, each photoelectric device being positioned to sense the speed of the bulbs in a different one of said channels.

4. The improved light bulb unscrambler means as defined in claim 1 further comprising:

a. motor means for driving said conveyor means, and

b. second electronic control means responsive to the number of operated blocking members to control the speed of said motor means.

5. The improved light bulb unscrambler means as defined in claim 4 wherein said electronic control means comprises:

a. preset counter means for counting the number of operated blocking members and containing a plurality of preset counts, and

b. pulse generator means coupled between said preset counter means and said motor means for incrementally changing the speed of said conveying means in accordance with the relationship between said preset counts and the actual count of the blocking members.

6. The improved light bulb unscrambler means as defined in claim 5 further comprising:

a. adjustable load set point means for determining a permissible range of bulb speeds which may be controlled by said preset counter means and said pulse generator means, and

b. means responsive to a bulb speed at either end of said permissible range for a predetermined time to adjust said load set point means to shift said permissible range.

7. An improved light bulb unscrambler means as defined in claim 4 further comprising bulb hold down means mounted over said channels to prevent bulbs from being ejected upwardly out of said channels.

8. An improved light bulb unscrambler means as defined in claim 4 wherein said separating means includes a plurality of rotating discs, said disarranged bulbs normally being inserted between pairs of said discs and rotated therewith to be discharged onto said conveying means, said separating means further comprising a plurality of spider wheels rotating in a direction opposite to said discs for dislodging bulbs carried on the peripheries of said discs.

9. An improved light bulb unscrambler means as defined in claim 4 further comprising a pair of spoked kicker wheels disposed over each of said channels and operating at different speeds for engaging a pair of interlocked bulbs and separating them.

Claims

1. In a light bulb traying machine including unscrambler means for separating a plurality of disarranged light bulbs into individual rows and discharging the bulbs onto conveying means, said conveying means including a plurality of moving belts defining channels therebetween for carrying said bulbs in a neckdown position, the bulbs moving from the input end to the output end of said conveying means, the improvement comprising: a. photoelectric sensing means between said input and output ends of said conveying means for sensing the speed of individual bulbs moving in each of said channels and for producing a bulb signal proportional to the time required for each bulb to pass said sensing means, b. blocking means including a plurality of blocking members each associated with a different one of said channels and individually operable to block bulbs from relatively slow moving channels of bulbs so that the bulbs are diverted to relatively fast moving channels of bulbs whereby all channels carry substantially the same number of bulbs, and c. first electronic control means responsive to bulb signals whose durations exceed a predetermined duration to produce a control signal to operate said blocking means.

2. The improved light bulb unscrambler means as defined in claim 1 further comprising means for continually modulating an operated blocking member between blocking and non-blocking positions.

4. The improved light bulb unscrambler means as defined in claim 1 further comprising: a. motor means for driving said conveyor means, and b. second electronic control means responsive to the number of operated blocking members to control the speed of said motor means.

5. The improved light bulb unscrambler means as defined in claim 4 wherein said electronic control means comprises: a. preset counter means for counting the number of operated blocking members and containing a plurality of preset counts, and b. pulse generator means coupled between said preset counter means and said motor means for incrementally changing the speed of said conveying means in accordance with the relationship between said preset counts and the actual count of the blocking members.

6. The improved light bulb unscrambler means as defined in claim 5 further comprising: a. adjustable load set point means for determining a permissible range of bulb speeds which may be controlled by said preset counter means and said pulse generator means, and b. means responsive to a bulb speed at either end of said permissible range for a predetermined time to adjust said load set point means to shift said permissible range.