CA1124271A - Pan stacking system - Google Patents
Pan stacking systemInfo
- Publication number
- CA1124271A CA1124271A CA386,535A CA386535A CA1124271A CA 1124271 A CA1124271 A CA 1124271A CA 386535 A CA386535 A CA 386535A CA 1124271 A CA1124271 A CA 1124271A
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- CA
- Canada
- Prior art keywords
- stack
- pan
- pans
- stage
- article
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
ABSTRACT OF THE DISCLOSURE
Articles which nest, such as baking pans, are assembled into a stack by a two-stage lift mechanism in which the assembly of a second stack is commenced while a previously assembled first stack is being discharged from the stack form-ing apparatus, so that the flow of pans into the apparatus need not be interrupted. Articles such as pans are fed in succession into a stacking station at which the articles are aligned with a vertical path and then dropped. A first stage lift receives the articles and is lowered one step upon the receipt of each article until the first stage lift is lowered to a transfer station. At the transfer station, support of the stack of articles is transferred to a second stage lift which is similarly lowered one step upon the addition of each subsequent article to the stack until a preselected number of articles have been accumulated in the stack. Upon transferring the support of the stack to the second stage lift, the first stage lift is retracted clear of the stack and returned to its upper limit of movement. When the final article has been stacked on the second stage lift, the first stage lift is re-inserted into the vertical path to receive the next following article to commence assembly of a second stack. Simultaneously, the second stage lift is lowered to a discharge station where the stack is discharged from the second stage lift which in then elevated back to the transfer station. The stacker is capable of stacking both bread and bun pans, which are of different height and capable of delivering pans to a discharge conveyor without stacking them.
Articles which nest, such as baking pans, are assembled into a stack by a two-stage lift mechanism in which the assembly of a second stack is commenced while a previously assembled first stack is being discharged from the stack form-ing apparatus, so that the flow of pans into the apparatus need not be interrupted. Articles such as pans are fed in succession into a stacking station at which the articles are aligned with a vertical path and then dropped. A first stage lift receives the articles and is lowered one step upon the receipt of each article until the first stage lift is lowered to a transfer station. At the transfer station, support of the stack of articles is transferred to a second stage lift which is similarly lowered one step upon the addition of each subsequent article to the stack until a preselected number of articles have been accumulated in the stack. Upon transferring the support of the stack to the second stage lift, the first stage lift is retracted clear of the stack and returned to its upper limit of movement. When the final article has been stacked on the second stage lift, the first stage lift is re-inserted into the vertical path to receive the next following article to commence assembly of a second stack. Simultaneously, the second stage lift is lowered to a discharge station where the stack is discharged from the second stage lift which in then elevated back to the transfer station. The stacker is capable of stacking both bread and bun pans, which are of different height and capable of delivering pans to a discharge conveyor without stacking them.
Description
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3 The present invention is especially adapted for 4 assembling bakery pans into a stack in which each layer of the stack consists of a single pan. Typically, prior art ~ apparatus for this purpose takes the form of an infeed con-7 veyor which conveys pans in succession onto a lift which is 8 indexed downwardly upon the receipt of each article until a 9 stack is formed. The stack is then discharged from the lift, after which the lift is elevated to its upper limit of move-11 ment to commence the formation of the next stack. Because 12 a certain amount of time is required to move the completed 13 stack of pans clear of the lift and to subsequently return 14 the lift to its upper limit of movement, it is necessary to interrupt the flow of pans to the lift while the two sequen-lB tial operations are being performed.
18 The present in~ention has, as one object, the 19 provision of a mechanism in which pans can be fed more rapidly and continuously into the stack forming apparatus 21 without the necessity of interrupting the flow of pans 22 during the stack discharge and lift return steps.
24 Another object of the invention is to provide a stacker which operates in conjunction with the demand 26 for pans downstream in the bakery production line.
~8 ~0 .Z71 1 ¦ In accordance with the present invention, a stack-
3 The present invention is especially adapted for 4 assembling bakery pans into a stack in which each layer of the stack consists of a single pan. Typically, prior art ~ apparatus for this purpose takes the form of an infeed con-7 veyor which conveys pans in succession onto a lift which is 8 indexed downwardly upon the receipt of each article until a 9 stack is formed. The stack is then discharged from the lift, after which the lift is elevated to its upper limit of move-11 ment to commence the formation of the next stack. Because 12 a certain amount of time is required to move the completed 13 stack of pans clear of the lift and to subsequently return 14 the lift to its upper limit of movement, it is necessary to interrupt the flow of pans to the lift while the two sequen-lB tial operations are being performed.
18 The present in~ention has, as one object, the 19 provision of a mechanism in which pans can be fed more rapidly and continuously into the stack forming apparatus 21 without the necessity of interrupting the flow of pans 22 during the stack discharge and lift return steps.
24 Another object of the invention is to provide a stacker which operates in conjunction with the demand 26 for pans downstream in the bakery production line.
~8 ~0 .Z71 1 ¦ In accordance with the present invention, a stack-
2 ¦ ing apparatus employs separate first and second stage lift
3 ¦ mechanisms which operate respectively along the upper and
4 ¦ lower portions of the vertical stacking path. The upper or
5 ¦ first stage lift mechanism supports the pans upon supports ~ ¦ which can be retracted clear of the stacking path when not in 7 ¦ use. In the assembly of a stack of pans, the initial pans of 8 ¦ the stack are assembled into a nested stack upon the supports 9 ¦ of the first stage lift, which is lowered one step upon the 10 ¦ receipt of each article. When a sufficient number of pans 11 ¦ have been accumulated on the first stage lift to find the first 12 ¦ stage lift lowered to a predetermined elevation, support of 13 ¦ the stack of pans is transferred to a second stage lift which 14 ¦ travels only along the lower portion of the vertical stacking l5 ¦ path. When the stack of pans has been received by the second 16 ¦ stage lift, the supports of the first stage lift can be re-17 ¦ tracted clear of the stack and the first stage lift is re-18 ¦ turned to its uppermost position with the supports retracted.
19 During this time, subsequent pans are assembled into the stack 20 ¦ supported on the second stage lift which, like the first stage 21 ¦ lift, is lowered one step upon the receipt of each pan.
23 ¦ When a predetermined number of pans have been ~4 ¦ accumulated in the stack, the second stage lift is dropped to 25 ¦ an article discharging position, while the supports of the 26 ¦ first stage lift are shifted back into their operative posi-27 ¦ tion to receive the next subsequent pan. Assembly of the first 28 ¦ portion of a second stack on the first stage mechanism is thus 2~ l ~0 l r,~Z71 1 accomplished while the second stage mechanism is being lowered 2 to its discharge position. The first assembled stack is then 3 discharged from the second stage mechanism, and as soon as the 4 stack clears the second stage mechanism, it is returned to its upper limit of movement to await receipt of the next partial ~ stack from the first stage mechanism.
8 The diverter conveyor section includes a discharge end, which can be positioned to feed the pans into the stack-ing apparatus from which they proceed to storage, or to divert 11 the articles to a bypass conveyor dependent on whether the 12 pans are required downstream. The diverter conveyor is run at 13 a somewhat higher speed than the infeed conveyor to create a 14 separation between the articles. The discharged articles are received by a catcher mechanism which supports and guides the 1~ pans until they reach a stop plate, at which time the kinetic 17 energy of the falling trailing end of the pan imparted to a 18 cam section of the catcher mechanism actuates the catcher 19 mechanism to release the pan to permit it to drop freely.
21 Other objects and features of the invention will 22 become apparent by reference to the following specification 23 and to the drawings.
Figure 1 is a side elevation, with certain parts 26 omitted, of a stacking apparatus embodying the present in-~7 vention;
~8 Figure 2 is an end view, with certain parts broken ~0 .Z~27~L
1 ¦ away or omitted, of the apparatus of Figure l;
2 ¦ Figure 3 is a top plan view of the apparatus as 5 ¦ shown in Figure 1, with certain parts broken away or omitted, 4 ¦ of the apparatus of Figure l;
5 ¦ Figure 4 is a perspective view of a catcher member ~ ¦ part employed in the apparatus of Figure l;
7 Figure 5 is a schematic diagram o~ an exemplary 8 form of electric control circuit for the apparatus of 9 Figure l; and Figures 6 - 12 are schematic side elevational 11 views similar to Figure 1, sequentially illustrating the 12 operation of the system.
14 Referring first particularly to Figure 1, apparatus embodying the invention is illustrated in a form employed to 1~ stack baking pans P. The pans, which will nest, one within 17 the other, when vertically stacked, are fed to the apparatus 18 via an elevated infeed conveyor designated generally 20. Ex-19 tending from the discharge end o~ conveyor 20 is a relatively short diverter conveyor 22, operable when in the full line 21 position shown in Figure 1, to feed pans P into the stacking 22 ¦ position. Conveyor 22 may alternatively be located in the 23 ¦ elevated position shown in broken lines in Figure 1 at 22' to, 24 ¦ on demand, divert incoming pans P directly to an upper endless 25 ¦ conveyor designated generally 24, pans so diverted being dis-~6 ¦ charged from the apparatus along the path of pans Pl and Pla Q7 l as shown in Figure 1 to a downstream discharge conveyor D
a8 wh ch leads to machinery in the ba~ery production line which _~_ 3Li.2~'7~
1 utilizes pans, such as dough dividers and depositors.
A double acting, fluid pressure operated cylinder 4 or motor 25 pivotally mounted at 25a on the frame F of the machine and having a piston rod 25b secured pivotally to ~ endless conveyor guide support 22b at 25c moves the conveyor 7 22 upwardly and downwardly~ The conveyor 22 further com-8 prises front and rear shafts 22c and 22d respectively on which 9 sprockets or sheaves 22e and 22f respectively are mounted to support endless member 22g. The supports 22b and 22c are 11 connected for raising and lowering movement about shaft 22d 12 as a pivot.
14 Provided to sense the presence of a pan on conveyor 22 is an electric eye E cooperating with a light source L
1~ and downstream of conveyor 24 is a second electric eye E' 17 cooperating with a second light source L' at discharge con-18 veyor D. When the lightsource to eye E' is blocked for more 19 than a predetermined time, the demand for pans downstream of the pan stacking unit is satisfied and pans on conveyor 22 21 will be delivered to the stacker for stacking.
23 In Figure 1, a pan P2 which is to be stacked by ~4 the apparatus is shown at an instant when the pan is partially discharged from the conveyor 22 and partially received by 26 what will be referred to as a catcher mechanism designated 27 generally 26. The catcher mechanism 26, which will be des-28 cribed in greater detail below, functions to temporarily 2~
~0 .Z4Z';tl 1 support the pan P2 being fed into the stacking apparatus to 2 carry the pan in movement beyond the discharge end of con-3 veyor 22 until the leading end of the pan P2 engages a stop 4 plate 28. Stop plate 28 is located to be engaged by the lead-ing end of the pan at the time the trailing end of the pan has
19 During this time, subsequent pans are assembled into the stack 20 ¦ supported on the second stage lift which, like the first stage 21 ¦ lift, is lowered one step upon the receipt of each pan.
23 ¦ When a predetermined number of pans have been ~4 ¦ accumulated in the stack, the second stage lift is dropped to 25 ¦ an article discharging position, while the supports of the 26 ¦ first stage lift are shifted back into their operative posi-27 ¦ tion to receive the next subsequent pan. Assembly of the first 28 ¦ portion of a second stack on the first stage mechanism is thus 2~ l ~0 l r,~Z71 1 accomplished while the second stage mechanism is being lowered 2 to its discharge position. The first assembled stack is then 3 discharged from the second stage mechanism, and as soon as the 4 stack clears the second stage mechanism, it is returned to its upper limit of movement to await receipt of the next partial ~ stack from the first stage mechanism.
8 The diverter conveyor section includes a discharge end, which can be positioned to feed the pans into the stack-ing apparatus from which they proceed to storage, or to divert 11 the articles to a bypass conveyor dependent on whether the 12 pans are required downstream. The diverter conveyor is run at 13 a somewhat higher speed than the infeed conveyor to create a 14 separation between the articles. The discharged articles are received by a catcher mechanism which supports and guides the 1~ pans until they reach a stop plate, at which time the kinetic 17 energy of the falling trailing end of the pan imparted to a 18 cam section of the catcher mechanism actuates the catcher 19 mechanism to release the pan to permit it to drop freely.
21 Other objects and features of the invention will 22 become apparent by reference to the following specification 23 and to the drawings.
Figure 1 is a side elevation, with certain parts 26 omitted, of a stacking apparatus embodying the present in-~7 vention;
~8 Figure 2 is an end view, with certain parts broken ~0 .Z~27~L
1 ¦ away or omitted, of the apparatus of Figure l;
2 ¦ Figure 3 is a top plan view of the apparatus as 5 ¦ shown in Figure 1, with certain parts broken away or omitted, 4 ¦ of the apparatus of Figure l;
5 ¦ Figure 4 is a perspective view of a catcher member ~ ¦ part employed in the apparatus of Figure l;
7 Figure 5 is a schematic diagram o~ an exemplary 8 form of electric control circuit for the apparatus of 9 Figure l; and Figures 6 - 12 are schematic side elevational 11 views similar to Figure 1, sequentially illustrating the 12 operation of the system.
14 Referring first particularly to Figure 1, apparatus embodying the invention is illustrated in a form employed to 1~ stack baking pans P. The pans, which will nest, one within 17 the other, when vertically stacked, are fed to the apparatus 18 via an elevated infeed conveyor designated generally 20. Ex-19 tending from the discharge end o~ conveyor 20 is a relatively short diverter conveyor 22, operable when in the full line 21 position shown in Figure 1, to feed pans P into the stacking 22 ¦ position. Conveyor 22 may alternatively be located in the 23 ¦ elevated position shown in broken lines in Figure 1 at 22' to, 24 ¦ on demand, divert incoming pans P directly to an upper endless 25 ¦ conveyor designated generally 24, pans so diverted being dis-~6 ¦ charged from the apparatus along the path of pans Pl and Pla Q7 l as shown in Figure 1 to a downstream discharge conveyor D
a8 wh ch leads to machinery in the ba~ery production line which _~_ 3Li.2~'7~
1 utilizes pans, such as dough dividers and depositors.
A double acting, fluid pressure operated cylinder 4 or motor 25 pivotally mounted at 25a on the frame F of the machine and having a piston rod 25b secured pivotally to ~ endless conveyor guide support 22b at 25c moves the conveyor 7 22 upwardly and downwardly~ The conveyor 22 further com-8 prises front and rear shafts 22c and 22d respectively on which 9 sprockets or sheaves 22e and 22f respectively are mounted to support endless member 22g. The supports 22b and 22c are 11 connected for raising and lowering movement about shaft 22d 12 as a pivot.
14 Provided to sense the presence of a pan on conveyor 22 is an electric eye E cooperating with a light source L
1~ and downstream of conveyor 24 is a second electric eye E' 17 cooperating with a second light source L' at discharge con-18 veyor D. When the lightsource to eye E' is blocked for more 19 than a predetermined time, the demand for pans downstream of the pan stacking unit is satisfied and pans on conveyor 22 21 will be delivered to the stacker for stacking.
23 In Figure 1, a pan P2 which is to be stacked by ~4 the apparatus is shown at an instant when the pan is partially discharged from the conveyor 22 and partially received by 26 what will be referred to as a catcher mechanism designated 27 generally 26. The catcher mechanism 26, which will be des-28 cribed in greater detail below, functions to temporarily 2~
~0 .Z4Z';tl 1 support the pan P2 being fed into the stacking apparatus to 2 carry the pan in movement beyond the discharge end of con-3 veyor 22 until the leading end of the pan P2 engages a stop 4 plate 28. Stop plate 28 is located to be engaged by the lead-ing end of the pan at the time the trailing end of the pan has
6 cleared conveyor 22 and its continuation support generally de-
7 signated 22a. When the leading end of the pan engages StQp
8 plate 28, the trailing end of the pan falls to engage cam
9 surfaces to be described on catcher mechanism 26 to cause the mechanism to release the pan to permit the pan to drop freely, 11 by gravity, either onto a first stage support mechanism de-12 signated generally 30 tif the pan is the first pan in a stack 13 being formed) or into the uppermost pan in a stack of pans 14 being formed. The location of stop plate 28 thus establishes the position of the left-hand side of a stack of nested pans 16 being formed by the apparatus as viewed in Figure 1.
1~ To form or assemble a stack of pans P, the pans P
19 are fed in succession to the apparatus along the infeed con-veyor 20 from right to left as viewed in Figure 1. The di-21 verter conveyor mechanism 22, to be described in more detail 22 later, is preferab]y driven at a speed greater than that of 23 the infeed conveyor 20 to separate the pans P and develop gaps 24 of predetermined length between them, dependent on pan length.
The pans normally proceed along infeed conveyor 20 in sub-26 stantially head to tail abutment, as the pans enter the stack-~7 ing apparatus. At the commencement of the formation of a ~8 stack of pans, the parts of the apparatus are in the position 2~
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1 shown in Figure 1, with the first stage support mechanism 30 2 located at its uppermost limit of movement, closely underlying 3 catcher mechanism 26, and a second stage support mechanism, 4 designated generally 32, also being located at its uppermost limit of movement, as shown in Figure 1. The first pan P2 ~ of the stack is discharged from diverter assembly sections 22 7 and 22a to slide laterally across catcher mechanism 26 from 8 right to left as viewed in Figure 1 until the leading or left-9 hand end of the pan P2 strikes catcher plate 28. At this time, 1~ as described above, the trailing end of the pan has cleared 11 the discharge end of the member 22a, and, upon falling to 12 engage catcher 26, the trailing end of the pan engages cam 13 surfaces on the catcher mechanism which cause the catcher 14 mechanism 26 to spread and drop the pan freely from the catcher mechanism onto the inwardly projecting support fingers 34 of 1~ the first stage support mechanism 30. The position of stop 17 plate 28 is adjustable toward and away from conveyor 22 to a 18 position which depends upon pan length, and the trailing end 19 o~ the pan remains supported upon conveyor 22 and its asso-ciated slide support 22a, until the leading end of the pan 21 strikes stop plate 28. The slide 22a, which forms a continu-22 ation of diverter conveyor 22, when the latter is in down 23 position, is connected to plate 28 and moves with it when ~4 plate 28 is adjusted.
~6 Referring to Figure 2, first stage support mechanism ~7 30 includes a carriage portion 36 which is guided in vertical 28 movement at each side of the machine on the fixed frame F
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1 o he machine as by rollers 38 engaging a track 40 on the 2 fixed machine frame. The carriage frame 36 of the first stage 3 support mechanism 30 is raised and lowered by means of a hy-4 draulic motor 42 whose piston rod 44 carries a pulley 46 about which is trained a cable 48 coupled to the main frame ~ 36 of the first stage support mechanism as at 50 and to the 7 main machine frame F as at 52. The c~ble and pulley arrange-8 ment employed multiplies the stroke of piston rod 44 by two 9 so that a displacement of one unit by piston rod 44 results in a vertical displacement of two units by carriage 36 of the 11 first stage support mechanism 30.
13 Returning to Figure 1, when the first pan P2 of 14 the stack to be formed drops onto support fingers 34 of first stage support mechanism 30, the pan blocks the light beam be-16 tween a light source Ll and an electrlc eye El so long as the 17 pan remains in this position. Blinding of eye El actuates a 18 preferably electric control circuit to in turn actuate hy-19 draulic motor 42 to lower the first stage support mechanism 30 until the pan P2 on support fingers 34 clears the light beam 21 from source Ll to electric eye El. The next pan, being fed 22 by the infeed conveyor system, which passes into the stacking 23 apparatus, and is handled by the catcher mechanism 26 and stop 24 plate 28 as described above, drops into the preceding pan supported on fingers 34, and actuates electric eye unit El ~6 and the control system to again lower first stage support ~7 mechanism 30 until the second pan clears the light source of ~8 electric eye El. This stacking process is cyclically repeated ~0 1 until support fingers 34 of first stage support mechanism 30 2 are lowered below support rollers 54 of second stage support 3 mechanism 32. As best seen in Figures 2 and 3, support rollers 4 54 are spaced from each other appropriately to permit fingers 34 to pass between rollers 54.
7 Lowering of first stage support mechanism 30 below 8 the level of support rollers 54 transfers support of the 9 stacked pans to support rollers 54. The control circuit at this time actuates a finger positioning mechanism designated 11 generally 56 on first stage support mechanism 30 to laterally 12 retract support fingers 34 clear of the stack of pans to the 13 position indicated in broken lines at 34' in Figure 1. Upon 14 retraction of the support fingers to the position shown at 34' in Figure 1, the first stage mechanism motor 42 is actuated 16 to elevate the first stage support mechanism back to its 17 original elevation closely beneath catcher mechanism 26; how-18 ever, the fingers 34 are maintained in the laterally retracted 19 stack clearing position for the time being.
21 Referring again to Figure 2, the second stage su 22 mechanism 22 includes a main carriage portion 58 which likewise 23 is guided for vertical movement on the main frame F of the 24 machine at each side thereof, as by rollers 60 guiding on fixed track 62. As was the case with the first stage support ~6 mechanism, a hydraulic motor 64 has its piston rod 66 provided 27 with a pulley 68, about which a cable 70 is trained to extend ~8 between carriage frame 58 of second stage support mechanism 32 2~
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1 as at 72 and the main frame F of the machine as at 74.
When support of the stack of pans is transferred, as 4 described above, to support rollers 54 of the second stage support mechanism 32, the adding of pans to the stack actuates ~ electric eye El as described above, however, actuation of the 7 eye is now employed by the control circuit to control motor 64 8 which cyclically lowers second stage support unit 32 and the 9 supported stack of pans in synchronism with the addition of pans to the upper end of the stack via conveyor 22.
12 When a predetermined number of pans have been placed 13 in the stack, motor 64 is actuated to lower second stage 14 support mechanism 32 to its lower end limit of movement, shown in broken lines at 32' in Figure 1, and, simultaneously with 18 this final lowering of second stage mechanism 32, the finger 17 positioning mechanism 56 is actuated to drive support fingers 18 34 of the first stage support mechanism back into their pan 19 receiving full line position shown in Figure 1. The stack of pans carried at this time on the second stage support mechanism 21 32 is discharged from the apparatus by actuation of a pusher 76 22 carried on second stage support mechanism 32 in a manner to be 23 described hereinafter. The di.scharging stack is pushed out of 24 the apparatus as a second stack is starting to be formed on first stage mechanism 30. After the first stack has been dis-26 charged, the control system, to be described below, returns the 27 second stage mechanism to its elevated position shown in full 28 lines in ~igure 1.
2~
~0 1 CATCHER MECH~NISM
2 The catcher mechanism 26 includes a pair of opposed 3 catcher members 78 of generally L-shaped transverse cross 4 section. Referring particularly to Figure 4 in which only one is shown because they are identical, each catcher mechanism 78 ~ includes a generally vertical web 80 having an outwardly pro-7 jecting flange 82 at its upper end upon which are mounted a 8 pair of lugs 84, bored as at 86 to constitute a pivotal 9 support for the member 78. A forwardly projecting toe flange 88 is integrally joined to the lower edge of vertical web 80 11 and may include an upwardly inclined longitudinally extending 12 shoe or wear plate 90. At one end of each member 78, an up-13 wardly inclined cam surface 92 extends between the toe and 14 upper end of the leg of the L-shaped member. Cam surface 92 is located at that end of the catcher member 78 which is ad-16 jacent the discharge end of the diverter section 22 when the 17 member 78 is assembled in the machine.
19 Referring now particularly to Figures 1 and 2, the catcher mechanism includes a pair of suspension plates 94 21 supported by frame F, each having a pair of bushings 96 fixedly 22 secured to the upper edge of the plate, the bushings 96 being 23 slidably supported on a pair of rods 98 fixedly mounted on ~4 the machine frame F. This particular mounting enables the transverse spacing between plates 94, as viewed in Figure 2, 26 to be adjusted to set up the mechanism for pans of specific 27 width.
28 Brackets 100 (Figure 2) are fixedly mounted on 2~ plates 94 and carry pivot pins 102 which are received within 2r~
1 the bored lugs 84 of mounting members 78 to support the members 2 78 for pivotal movement about horizontal axes on plates 9~, between the full line position and broken line position shown 4 in Figure 2. Threaded counterweights 104 are adjustably mounted on member 78 on threaded rods 104a and are employed to gravita-8 tionally bias the members 78 to the full line positions shown 7 in Figure 2.
9 With catcher members 78 in the full line positions shown in Figure 2, a pan being discharged from diverter section 11 22, as shown in Figure 1, is projected forwardly and downwardly 12 from the diverter sections 22 and 22a until its forward bottom 13 edge strikes and becomes supported upon the toe sections 90 of 14 the opposed catcher members 78. The cam member 92 of each catcher member 78 is located at the end of the member 78 lG (Figure 1) which is adjacent to the diverter section, and hence 17 during the initial approach of the pan to catcher member 78, 18 the bottom of the pan passes above and clear of each cam 19 section 92. To assist the pan in clearing the cam section 92, the ramp support 22a is located in the space between the end 21 of the diverter section 22 and the adjacent ends of catcher 22 member 78. The momentum imparted to the pan by diverter 23 section 22 drives the pan to the left as viewed in Figure 1, 24 until the left-hand or leading end of the pan strikes stop plate 28. At this time, the trailing end of the pan bottom 2~ has cleared diverter section 22 and ramp 22a and thus is en-27 tirely unsupported. The trailing end of the pan then drops 28 until its strikes the inwardly inclined cam portions 92 of the 2~ catcher member. The weight of the pan is sufficient to cause ~0 1 the pan to slide downwardly on these inclined cam sections 92 2 to thus swing the catcher members 78 outwardly to the broken 3 line position of Figure 2. This separating movement of the 4 adjacent opposed catcher members withdraws their support from the pan to permit the pan to drop freely between the now ~ spread catcher members 78 onto support fingers 34 of the first 7 stage support mechanism 30. As soon as the pan has passed be-8 low the catcher members 78, by the lowering movement of the g first stage support mechanism as described above, the counter-weights 104 gravitationally bias the catcher members back into 11 their pan receiving position.
13 FIRST ST:~OE SUPPORT ~C:~NIS~I
14 The main frame of the first stage support mechanism 30 is of generally U-shaped configuration when viewed from 1~ above and includes a pair of spaced parallel side members 108 17 each of which, referring to Figure 2, has bracket plates 110 18 fixedly secured to one end, the bracket plates 110 being fixedly 19 secured to each other by a transversely extending channel shaped frame member 112. As best seen in Figures 1 and 2, the 21 horizontally projecting side frame members 108 are each pro-22 vided with a pair of spaced lugs 114 which serve as a pivotal 23 support for finger frame assemblies 116, the finger frame ~4 assemblies 116 including a horizontally extending frame member 25 118 (Figure 2) which is pivotally supported at opposite ends 26 in lugs 114 as at pivots 120. Each finger frame assembly 116 ~7 further includes a pair of upright frame members 122 fixedly ~8 secured at their lower ends to member 118 and at their upper g~
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1 ends to a horizontally extending cross member 124 upon which 2 the support fingers 34 are fixedly mounted.
4 Mechanism for swinging fingPr frame assemblies 116 about pivots 120 between the pan supporting position shown ~ in full line in Figure 1 and the stack clearing position 7 indicated in broken line in Figure 1 includes a hydraulic 8 motor 126 whose cylinder is pivotally mounted upon a bracket 9 128 fixedly secured to one of the frame hrackets 110. The piston rod 130 of motor 126 is pivotally connected as at 132 11 (Figure 2) to the central portion of a link 134. One end of 12 link 134 is pivotally mounted as at 136 upon cross frame mem-13 ber 112, the pivot 136 being constituted by a shaft 138 which, 14 (see particularly Figure 3), extends transversely of the ma-chine and supports a second link 134a, identical to link 134.
1~
17 As best seen in Figure 3, the ends of links 134 and 1~ 134a remote from their common supporting shaft 138 are formed 19 with outwardly projecting universal joint extensions 142, 142a, which serve as pivotal mounts for drive links 146, 146a. Re-21 ferring to Figure 2, drive link 146 is pivotally connected at 22 its lower end as at 150 to crank arm 152 (see Figures 1 23 and 3) which is fixedly secured to and projects outwardly 24 from finger frame 116. As best seen in Figures 1 and 3, a similar connection is made from link 146a to the finger frame 26 at the opposite side of the machine.
28 Referring first to Figure 2, it is seen that if 2~ hydraulic cylinder 126 is actuated to retract its piston rod 1 130, link 134 (and link 134a) will be swung downwardly about 2 pivot 136, thereby driving the outer ends of these two links 3 downwardly to drive drive links 146 and 146a downwardly. Re-4 ferring now to Figure 1, it is seen that if the links 146 and 146a are driven downwardly, downward movement of crank arm ~ 152, rigidly secured to the finger frame 116, will cause 7 finger frame 116 to pivot outwardly about its pivot 120 to 8 swing the support fingers 34 on the opposed finger frames 116 9 outwardly away from each other to the retracted configuration indicated in broken line in Figure 1. Subse~uent extension 11 of the piston rod 130 of drive motor 126 will drive the finger 12 frames back toward each other to the full line position shown 13 in Figure 1.
The control circuit is so arranged that movement of 1~ the finger frames 116 from the article supporting position to 17 the outward stack clearing position is accomplished when the 18 first stage support mechanism 30 has reached its lower end 19 limit of movement. A control circuit, in a manner to be described hereinafter, maintains the finger frames in their 21 outwardly spread, inoperative positions while the first stage 22 support assembly 30 is returned to its upper elevated posi-23 tion. Actuation of motor 126 to restore the finger frames 24 to their article supporting position is initiated in the control circuit in response to the lowering of the second ~6 stage support mechanism 32 to its lowered, stack discharging ~7 position.
~8 SECOND STAGE :SUPPORT MECEANISM
As previously described, frame 58 is guided in ~0 1 vertical movement on the main machine frame as by rollers 60 2 guided in tracks 62. Hydraulic motor 64 whose piston rods 66 3 carries a pulley 68 engaged with a cable 70 is employed to raise 4 and lower frame 58 relative to the main machine frame.
Frame 58 further supports a pusher 76 (Figure 3) B slidably supported on frame 58 for movement from left to right 7 or vice versa as viewed in Figure 2. As best seen in Figures 8 1 and 3, pusher 76 moves laterally across the central portion 9 of the supporting surface defined by rollers 54. The pusher is coupled to a chain 156 operatively trained about a pair of end 11 sprockets 158, 160 which are rotatably mounted on the frame 58 12 of mechanism 32. A drive motor 162 is mounted upon frame 58 13 and is coupled through a chain and sprocket mechanism designated 14 generally 164 to drive sprocket 158.
15 After support of a stack of pans has been transfe~ed .
18 to the second stage support mechanism 32, with the mechanism 17 32 located in its elevated position shown in full line in 18 Figure 1, the support platform defined by rollers 54 is 19 lowered in step-by-step movement in synchronism with the addition of pans to the stack as detected by electric eye El.
21 The control system is normally set to indicate the completion 22 of a stack of a selected number of pans by the engagement of 23 frame 58 with the striker of a limit switch mounted on the ~4 main machine frame F at an appropriate el.evation, this eleva-tion being located at some distance above a lower limit of 26 movement of second stage mechanism 32. Upon the loading of 27 the final pan into the stack supported upon second stage ~8 mechanism 32, the control circuit transfers control of the 2~
~0 1 second stage mechanism motor 64 from electric eye ~1 and causes 2 the motor to drop mechanism 32 in continuous movement to its lower end limit of movement. The purpose of completing the 4 stack before mechanism 32 has reached its lower end limit of movement is so that the assembly of a second stack of articles ~ can commence during that period of time while the completed 7 stack is being discharged from the apparatus. The control cir-8 cuit is so arranged that when the stack is completed and the 9 second stage mechanism begins to drop in continuous movement toward its lower end limit of movement, motor 126 of the first 11 stage mechanism, which is at this time at its upper end limit 12 of movement with its support fingers retracted, is operated to 13 drive the support fingers 34 into their article supporting 14 position so that the pan following the final pan of the com-pleted stack into the apparatus becomes the first pan of the ~ next stack. Assembly of the second stack thus commences while 17 second stage mechanism 32 is carrying the completed stack to 18 the lower end limit of movement for subsequent discharge by 19 appropriate actuation of motor 162 to translate pusher 76 across a platform defined by rollers 54 to discharge the com-21 pleted stack from the machine. As soon as the stack is dis-22 charged, pusher 76 is retracted and second stage mechanism 32 23 is returned to its upper end limit of movement to await receipt ~4 of the stack being formed at this time on the first stage support mechanism.
~6 CONTROL SYS~EM
27 In a typical electrical control system, first stage ~8 motor 42, second stage motor 64, finger actuating motor 126 and pusher actuating motor 162 are respectively actuated by ~0 2~
1 solenoid operated four-way reversing valves employed in a con-2 ventional manner to make the appropriate connections between 3 the respective motors and a source of ~luid pressure and sump.
4 Energization of the various valve actuating solenoids is accom-plished by an electric control circuit which includes various ~ limit switches, electric eye detectors, and counters to initiate 7 the appropriate control actions in response to the movement of 8 articles or various parts of the apparatus. Preferably, a 9 programmable controller such as the Mini-PMC programmable con-troller sold by Allen Bradley Co. under catalog No. 1755A
11 is employed in the electrical control circuit. Such controller 12 can readily be programmed in a relatively simple manner to per-13 form a wide variety of control functions.
For purposes of explanation, however, an extremely 1~ simplified form of electrical control circuit is shown in 17 Figure 5 to indicate the manner in which control circuit 18 functions.
As an initial starting condition, it will be assumec 21 that parts of the apparatus are in the positions shown in full 22 line in Figure 1 of the drawings. In this condition, the first 23 stage support mechanism 30 is at its upper end limit of move-24 ment, with support fingers 34 being located in their inner pan supporting position. Second stage support mechanism 32 is 26 likewise located at its upper limit of movement, with pusher 27 member 76 in its retracted, inoperative position.
~8 2~ In the exemplary form of control circuit illustrate~
l limit switches LSl and LS2 (Figure 1) are mounted on the ma-2 chine frame to have their strikers depressed when flrst staye mechanism 30 is in its "up" position (LSl) or its "lower"
4 position (LS2). Referring to Figure 2, limit switches LS3 and S LS4 are located on the main frame 36 of first stage mechanism B 30 to respectively detect the finger frame 116 position when 7 the fingers are "in" (LS3) or "retracted" (LS4). Limit switches 8 LS5 and LS6 detect the position of the second stage support ~ mechanism 32 at its "upper" (LS5) or "lower" (LS6) position.
Limit switch LS7 is mounted on the machine frame to be engaged 11 by the second stage mechanism when the stack of pans supported 12 on the second stage mechanism reaches a predetermined height.
LS7 may be mounted for vertical adjustment on the machine frame 14 to select the number of pans to be included in a stack. A
limit switch LS8 is mounted on the discharge conveyor (not lB shown), which receives the stack of pans ejected by pusher 17 mechanism 76, actuation of the striker of limit switch LS8 18 signaling the fact that the stack of pans has been discharged l9 clear of the stacking apparatus.
21 With the first stage raised and support fingers 34 22 in their "in" position, and second stage mechanism 32 at its 23 "elevated" position with pusher 76 retracted, energization of 24 the control circuit by actuation of a suitable start button (not shown) conditions the control circuit to commence a stack-26 ing cycle.
~7 28 The pans are fed by the infeed conveyor onto diver~
2~ section 22 which feeds the pan into catcher mechanism 26 which, ~0 1 as described above, drops the first pan onto the support 2 fingers 34. As the pan drops onto fingers 34, it blocks the 3 light beam from light source Ll to electric eye El, thus 4 closing the contacts Ela of the control circuit of Figure 5.
Closure of contacts Ela completes a circuit through solenoid ~ SOlD between supply lines Ll and L2 via contacts LS3a (closed 7 because the fingers are in their "in" positions) and normally 8 closed contact LS2a which are closed at this time because the 9 first stage mechanism is not at its lower position. Solenoid SOlD positions the valve controlling the first stage lift 11 motor 42 to cause motor 42 to index the first stage mechanism 12 32 downwardly until the pan supported on fingers 34 clears 13 the electric eye beam, at which time contacts Ela open to 14 deenergize solenoid SOlD.
1~ A similar cycle is repeated as successive pans are 17 fed into the apparatus and added to the stack until the first 18 stage mechanism reaches its lowermost position. When the 19 first stage mechanism reaches its lower limit of movement, the striker of limit switch LS2 is engaged and actuated to 21 close contacts LS2b and to simultaneously open normally 22 closed contacts LS2a.
24 Closure of contacts LS2b energizes solenoid SOFO via contacts LS5a, which are closed at this time because second 26 stage mechanism 32 is at its upper limit of movement and 27 the striker of limit switch LS5 is actuated. Solenoid SOFO, ~8 when energized, actuates the finger frame operating motor 126 2~ to retract its piston rod, thereby swinging the fingers 34 clea~
~0 1i ~.Z4~1 1 of the stack to the broken line positions shown in Figure 1.
2 When the fingers are fully retracted, contacts LS3a are opened 3 and contacts LS4a are closed. closure of contacts LS4a con-4 ditions solenoid S02D to be energized under the control of electric eye contacts Ela via normally closed contacts LS6a, ~ which are closed at this time because the second stage mechanism 7 is not at its lower end limit of movement. Solenoid S02D, 8 when energized, causes the second stage lift motor 64 to lower 9 the second stage. With contacts LS4a and LS6a closed, the cyclic interruption of the electric eye beam by pans being 11 added to the stack actuates the electric eye contacts Ela which 12 now cyclically actuate solenoid S02D to actuate the second 13 stage lift motor 64 in downward indexing movement as pans are 14 added to the stack.
1~ When the second stage mechanism is lowered to a 17 position indicating the stack to be complete, the second stage 18 mechanism actuates limit switch LS7 to close contacts LS7a 19 which energizes a lock-in relay Rl via normally closed contacts LS6b, closed at this time because the second stage is not at 21 its lower end limit of movement. When relay Rl is energized, Z2 it closes contacts Rla which bypass the electric eye contacts 23 Ela and contacts LS4a to maintain solenoid S02D energized, 24 causing the second stage mechanism to be continuously lowered by the second stage lift motor 64 until the second stage 26 reaches its lower end limit of movement, at which time contacts ~7 LS6a and LS6b open to deenergize solenoid S02D and relay Rl.
~8 Contacts Rla also lock in relay Rl during this downward move-2~ ment of the second stage.
~0 iL~.Z~7~
1 When support fingers 34 are retracted by the pre-2 viously described actuation of the finger positioning motor 3 126, contacts LS4b close, as soon as the fingers 34 are fully 4 retracted, to energize solenoid SOlU via normally closed con-tacts LSlb to actuate the first stage lift motor 42 to raise ~ the first stage support mechanism 30 to its upper limit of 7 movement. When the first stage mechanism reaches its upper 8 limit of movement, contacts LSlb open to deenergize solenoid 9 SOlU. Fingers 34 remain in their retracted stack clearing position until limit switch LS7, as described above, is 11 actuated by the second stage mechanism upon the completion 12 of the assembly of the stack.
14 At the completion of the stack, contacts LS7c are closed, and contacts LSlc are likewise closed at this time 16 because the first stage is back at its upper position.
17 Closure of these latter two contacts energizes solenoid SOFI
18 which actuates to return fingers 34 to their inner stack 19 supporting po~itions to catch the next subsequent pan fed into the machine to begin forming a second stack while the 21 second stage mechanism is being lowered to its lower end 22 limits of movement to discharge the assembled stack from the 23 apparatus. A control relay R3 is connected in parallel with ~4 solenoid SOFI to lock the finger positioning solenoid SOFI
in its energized position via contacts R3a and normally closed 26 contacts LS2c, which are closed at all times when the first ~7 stage mechanism is away from its lower end limit of movement.
2~ When the second stage mechanism reaches its lower ~0 2'7~
8 end limit of movement, contacts LS6c are closed to energize 3 motor 162 of the pusher mechanism via solenoid SOBO to actuate 4 pusher 76 to push the completed stack from the lowered second stage mechanism. When the stack finally clears the apparatus, ~ it actuates limit switch LS8 to open normally closed contacts 7 LS8a, thereby deenergizing the pusher out actuating solenoid, 8 and simultaneously closing contacts LS8b. Closure of contacts 9 LS8b simultaneously energizes solenoids SOPR, S02U, and a lcok-in relay R4. Solenoid SOPR, when energized, actuates the 11 pusher motor to retract pusher 76 to its normal inoperative 12 position. When the pusher reaches its inoperative position, 13 it actuates a limit switch LS9 to open contact LS9a to de-14 energize solenoid SOPR.
1~ Solenoid S02U, when energized, conditions the second 17 stage lift motor 64 to stroke upwardly to return the second 18 stage mechanism to its normal upper position. Solenoid 19 S02U remains energized until the second stage mechanism arrives at its uppermost position, at which time limit switch 21 LS5 is engaged to open its normally closed contact LS5b to 22 deenergize solenoid S02U and a lock-in relay R4. Lock-in 23 relay R4, when energized, closes lock-in contacts R4a which ~4 bypass contact LS8b to maintain solenoids SOPR and S02U
energized in the event the ejected stack should move beyond ~6 the stack clear detecting limit switch LS8 before the pusher ~7 is fully retracted and the second stage has been returned 28 to its uppermost limit of movement.
~0 7~L
1 As described above, a second stack is being formed 2 on the first stage mechanism, from that point in the cycle 3 described previously when the first stack is completed and 4 the second stage, with the completed stack, begins to move toward its lower end limit of movement for the subsequent ~ discharge of the stack and the restoring of the second stage 7 to its original upper end limit of movement.
9 Also provided in the circuit (see the lower end thereof) are solenoids A and B which are the advance and re-11 tract solenoids respectively for the conventional cylinder 25 12 controlling diverter conveyor 22. The eye E has contacts Ea 13 and Eb in series with the solenoids A and B respectively 14 and a conventional timer T in series with contacts Rla of eye E' has contacts Tl and T2 also in series with the solenoids 1~ A and B respectively. Timer contacts Tl in series with 17 solenoid A, and T2 in series with solenoid B, will not be 18 operated unless the timerT is energized for a predetermined 19 period, i.e. one and one-half seconds to indicate that pans have piled up on conveyor D and future pans proceeding to 21 conveyor 22 should be stacked. Moreover, so long as the eye E
22 light path is broken by a pan on conveyor 22, the conveyor 22 23 cannot be moved so that any pan in a forward position on 24 conveyor 22 discharges from conveyor 22 before conveyor 22 shifts. Assuming conveyor 22 is in the up (broken lines) 26 position, pans feed along conveyors 94 and D and eye E' is 27 now blocked for a long enough period to change the position ~8 of conveyor 22. When pans pile up on conveyor D the eye E' 2~ will be blocked for a longer period than the predetermined ~0 .Z~271 1 period chosen and contacts Tl and T2 will open and close 2 respectively. Assuming eye E is not at the time blocked, 3 solenoid A will be deenergized, and solenoid B energized to 4 shift conveyor 22 to the down position. Timer T is an auto-matically resetting timer. The gap forward of conveyor 22 ~ is selected with respect to the length tcenter of gravity) 7 of the pans P such that a continuous flow of pans P can be 8 maintained regardless of the position of conveyor 22.
The exemplary control circuit illustrated, of ll course, for the sake of clarity, omits many conventional 12 elements employed in the actual machine, such as manual in~
13 ¦ dexing buttons which can be employed to manually position 14 the various elements as desired. Moreover, it is to be under-stood the positions of the various limit switches can be ad-16 justed to process either bread or bun pans.
l9 The manner in which articles are stacked is schema-tically illustrated in sequential views in Figures 6-12.
22 Referring first to Figure 6, portions of the first 23 stage mechanism 30 and second stage mechanism 32 are shown 24 in the positions occupied at the commencement of a stacking operation. Both of the first stage mechanism 30 and second ~6 stage mechanism 32 are located in their uppermost limit of ~7 movement with the first stage mechanism 30 located in its ~8 operative position with fingers 34 in their inner pan re-2~ ceiving position. Pans P to be stacked are being fed to the ~0 .Z~27~
1 apparatus by infeed conveyor 20 and diverter section 22 with 2 the first pan P of the stack being shown in Figure 6 just as 3 it is striking fixed stop 28. For purposes of clarity, the 4 gravity operated catcher mechanism 24 has not been shown in the schematic views.
7 In Figure 7, the apparatus is shown with a first 8 group of pans assembled into the partial s~ack Sl supported 9 upon the first stage mechanism 30 which, as compared to the position shown in Figure 6, has been indexed to lowered 11 positions to keep the uppermost pan in the stack Sl below 12 the path of movement of subsequent pans P into the stack.
14 In Figure 8! first stage mechanism 30 has been lowered to its lowermost limit of movement, and the support 16 of the partial stack of pans Sl has been transferred to 17 second stage mechanism 32. The first stage mechanism has been 18 actuated to retract its fingers 34 clear of the partial stack 19 Sl. As indicated in Figure 8, pans P continue to be fed into the apparatus.
22 In Figure 9, the apparatus is shown at the instant 23 the final pan PA of a stack is striking fixed stop 28. As 24 compared to Figure 8, it will be observed that the first stage mechanism 30 is, at this time, located at its upper limit of 26 movement, however, the support fingers of the first stage 27 mechanism are still retracted clear of the stack. The next au S sequent pan PB is just entering diverter section 22.
7~
1 In Figure 10, the second stage mechanism is being 2 lowered in continuous movement, and the first stage mechanism has returned to its inner pan supporting position in time to 4 receive the first pan PB of the next subsequent stack to be formed. The completed stack Sl is being lowered in con-tinuous movement by second stage mechanism 32 to the outfeed r conveyor 32'.
9 In Figure 11, the second stage mechanism has been lowered to its lower limit of movement and the completed 11 first stack is being pushed by pusher member 76 in a direction 12 away from the observer in Figure 11 onto outfeed conveyor 32'.
While the first assembled stack Sl is discharging, it will 14 be observed that a partial second stack S2 is being assembled on first stage mechanism 30.
17 In the next sequential view of Figure 12, the first 18 assembled stack S1 has been removed from the apparatus by 19 outfeed conveyor 32' and the second stage mechanism 3 has been returned to its upper limit of movement where it awaits 21 receipt of the second partial stack S2 being assembled on 22 the first stage mechanism. The views of Figures 7 and 12 23 show essentially the same stage in the stack forming operation 24 and the apparatus continues to cycle from the Figure 7 -Figure 12 stage through the successive steps shown in Figures 26 8, 9, 10, 11 and 12.
~8 With the apparatus, high average stacking rates in 2~ the neighborhood of 50 pans per minute are feasible and the l~.Z~Z'^~l 1 fast-acting, low inertia diverter system (22 etc.) can direct 2 pans to the stacking mechanism or to an overhead conveyor without having to stop the flow o pans. Because the catcher 4 26 which initially receives the pans for stacking is self-releasing, it can operate at a faster rate than a stacker ~ which employs a motor operated releasing system, and in which 7 rate of stack time is sacrificed because of the time delay 8 necessary to the operation of sensors and motors. For example, 9 a motor operated pan-catcher might conceivably take 3/lOths of a second more to operate and this cumulatively would 11 clearly restrict the rate of operation of the stacking machine.
12 Moreover, the gravity operated catcher described is smoother 13 in operation and does not have the problem of the rapid wearing 14 of fast-operating drive linkage.
lB The present system is also versatile. For instance, 17 the full dead weight of each pan being processed is counter-18 balanced out, so that essentially cam leverage causes the 19 opening of the catcher arms. Thus, a range of pans of different weight can be handled without changing anything, 21 because it is the dead weight of the entire pan which is 22 counter-balanced out and the full weight of the pan is never 23 a factor until the tail end of the pan drops to the catcher 24 pan mechanism. Finally, it is the kinetic energy of the 25 ¦ falling pan acting through the cam leverage which causes the 26 ¦ catcher arms 78 to open. In this sense, the catcher is some-27 ¦ what insensitive to weight and permits a good range of pan ~8 ¦ weights to be handled without ad~ustment of the counter-weights 2~ 104 along rods 104a. For example, pans in the range of 18 ko ~0 ~:I.Z4Z7,.
l 32 inches long, and 8 to 32 inches wide, and weighing 8 to 2 15 pounds can be readily handled. Moreover, the system can 3 be switched from bread pans to bun pans of various heights 4 with no lost time between the completion of one stack of pans and the start of another stack except for any time required 6 for adjusting to any pan length and width changes. Moreover, 7 the system can stack aluminum pans because no magnets are 8 required and pans which are either right-side up or upside 9 down. Minimum machine adjustments are required for pan di-$0 mension variations and the machine is a very low maintenance ll machine.
13 While one embodiment of the invention has been 14 described in detail, it will be apparent to those skilled in the art that the disclosed embodiment may be modified. There-l~ fore, the foregoing description is to be considered exemplary 17 rather than limiting, and the true scope of the invention i5 2~ t t defined in the following claims.
~6 ~8 2~
~0
1~ To form or assemble a stack of pans P, the pans P
19 are fed in succession to the apparatus along the infeed con-veyor 20 from right to left as viewed in Figure 1. The di-21 verter conveyor mechanism 22, to be described in more detail 22 later, is preferab]y driven at a speed greater than that of 23 the infeed conveyor 20 to separate the pans P and develop gaps 24 of predetermined length between them, dependent on pan length.
The pans normally proceed along infeed conveyor 20 in sub-26 stantially head to tail abutment, as the pans enter the stack-~7 ing apparatus. At the commencement of the formation of a ~8 stack of pans, the parts of the apparatus are in the position 2~
~0 ~ z~z~
1 shown in Figure 1, with the first stage support mechanism 30 2 located at its uppermost limit of movement, closely underlying 3 catcher mechanism 26, and a second stage support mechanism, 4 designated generally 32, also being located at its uppermost limit of movement, as shown in Figure 1. The first pan P2 ~ of the stack is discharged from diverter assembly sections 22 7 and 22a to slide laterally across catcher mechanism 26 from 8 right to left as viewed in Figure 1 until the leading or left-9 hand end of the pan P2 strikes catcher plate 28. At this time, 1~ as described above, the trailing end of the pan has cleared 11 the discharge end of the member 22a, and, upon falling to 12 engage catcher 26, the trailing end of the pan engages cam 13 surfaces on the catcher mechanism which cause the catcher 14 mechanism 26 to spread and drop the pan freely from the catcher mechanism onto the inwardly projecting support fingers 34 of 1~ the first stage support mechanism 30. The position of stop 17 plate 28 is adjustable toward and away from conveyor 22 to a 18 position which depends upon pan length, and the trailing end 19 o~ the pan remains supported upon conveyor 22 and its asso-ciated slide support 22a, until the leading end of the pan 21 strikes stop plate 28. The slide 22a, which forms a continu-22 ation of diverter conveyor 22, when the latter is in down 23 position, is connected to plate 28 and moves with it when ~4 plate 28 is adjusted.
~6 Referring to Figure 2, first stage support mechanism ~7 30 includes a carriage portion 36 which is guided in vertical 28 movement at each side of the machine on the fixed frame F
.Z~
1 o he machine as by rollers 38 engaging a track 40 on the 2 fixed machine frame. The carriage frame 36 of the first stage 3 support mechanism 30 is raised and lowered by means of a hy-4 draulic motor 42 whose piston rod 44 carries a pulley 46 about which is trained a cable 48 coupled to the main frame ~ 36 of the first stage support mechanism as at 50 and to the 7 main machine frame F as at 52. The c~ble and pulley arrange-8 ment employed multiplies the stroke of piston rod 44 by two 9 so that a displacement of one unit by piston rod 44 results in a vertical displacement of two units by carriage 36 of the 11 first stage support mechanism 30.
13 Returning to Figure 1, when the first pan P2 of 14 the stack to be formed drops onto support fingers 34 of first stage support mechanism 30, the pan blocks the light beam be-16 tween a light source Ll and an electrlc eye El so long as the 17 pan remains in this position. Blinding of eye El actuates a 18 preferably electric control circuit to in turn actuate hy-19 draulic motor 42 to lower the first stage support mechanism 30 until the pan P2 on support fingers 34 clears the light beam 21 from source Ll to electric eye El. The next pan, being fed 22 by the infeed conveyor system, which passes into the stacking 23 apparatus, and is handled by the catcher mechanism 26 and stop 24 plate 28 as described above, drops into the preceding pan supported on fingers 34, and actuates electric eye unit El ~6 and the control system to again lower first stage support ~7 mechanism 30 until the second pan clears the light source of ~8 electric eye El. This stacking process is cyclically repeated ~0 1 until support fingers 34 of first stage support mechanism 30 2 are lowered below support rollers 54 of second stage support 3 mechanism 32. As best seen in Figures 2 and 3, support rollers 4 54 are spaced from each other appropriately to permit fingers 34 to pass between rollers 54.
7 Lowering of first stage support mechanism 30 below 8 the level of support rollers 54 transfers support of the 9 stacked pans to support rollers 54. The control circuit at this time actuates a finger positioning mechanism designated 11 generally 56 on first stage support mechanism 30 to laterally 12 retract support fingers 34 clear of the stack of pans to the 13 position indicated in broken lines at 34' in Figure 1. Upon 14 retraction of the support fingers to the position shown at 34' in Figure 1, the first stage mechanism motor 42 is actuated 16 to elevate the first stage support mechanism back to its 17 original elevation closely beneath catcher mechanism 26; how-18 ever, the fingers 34 are maintained in the laterally retracted 19 stack clearing position for the time being.
21 Referring again to Figure 2, the second stage su 22 mechanism 22 includes a main carriage portion 58 which likewise 23 is guided for vertical movement on the main frame F of the 24 machine at each side thereof, as by rollers 60 guiding on fixed track 62. As was the case with the first stage support ~6 mechanism, a hydraulic motor 64 has its piston rod 66 provided 27 with a pulley 68, about which a cable 70 is trained to extend ~8 between carriage frame 58 of second stage support mechanism 32 2~
Z7~ ~
1 as at 72 and the main frame F of the machine as at 74.
When support of the stack of pans is transferred, as 4 described above, to support rollers 54 of the second stage support mechanism 32, the adding of pans to the stack actuates ~ electric eye El as described above, however, actuation of the 7 eye is now employed by the control circuit to control motor 64 8 which cyclically lowers second stage support unit 32 and the 9 supported stack of pans in synchronism with the addition of pans to the upper end of the stack via conveyor 22.
12 When a predetermined number of pans have been placed 13 in the stack, motor 64 is actuated to lower second stage 14 support mechanism 32 to its lower end limit of movement, shown in broken lines at 32' in Figure 1, and, simultaneously with 18 this final lowering of second stage mechanism 32, the finger 17 positioning mechanism 56 is actuated to drive support fingers 18 34 of the first stage support mechanism back into their pan 19 receiving full line position shown in Figure 1. The stack of pans carried at this time on the second stage support mechanism 21 32 is discharged from the apparatus by actuation of a pusher 76 22 carried on second stage support mechanism 32 in a manner to be 23 described hereinafter. The di.scharging stack is pushed out of 24 the apparatus as a second stack is starting to be formed on first stage mechanism 30. After the first stack has been dis-26 charged, the control system, to be described below, returns the 27 second stage mechanism to its elevated position shown in full 28 lines in ~igure 1.
2~
~0 1 CATCHER MECH~NISM
2 The catcher mechanism 26 includes a pair of opposed 3 catcher members 78 of generally L-shaped transverse cross 4 section. Referring particularly to Figure 4 in which only one is shown because they are identical, each catcher mechanism 78 ~ includes a generally vertical web 80 having an outwardly pro-7 jecting flange 82 at its upper end upon which are mounted a 8 pair of lugs 84, bored as at 86 to constitute a pivotal 9 support for the member 78. A forwardly projecting toe flange 88 is integrally joined to the lower edge of vertical web 80 11 and may include an upwardly inclined longitudinally extending 12 shoe or wear plate 90. At one end of each member 78, an up-13 wardly inclined cam surface 92 extends between the toe and 14 upper end of the leg of the L-shaped member. Cam surface 92 is located at that end of the catcher member 78 which is ad-16 jacent the discharge end of the diverter section 22 when the 17 member 78 is assembled in the machine.
19 Referring now particularly to Figures 1 and 2, the catcher mechanism includes a pair of suspension plates 94 21 supported by frame F, each having a pair of bushings 96 fixedly 22 secured to the upper edge of the plate, the bushings 96 being 23 slidably supported on a pair of rods 98 fixedly mounted on ~4 the machine frame F. This particular mounting enables the transverse spacing between plates 94, as viewed in Figure 2, 26 to be adjusted to set up the mechanism for pans of specific 27 width.
28 Brackets 100 (Figure 2) are fixedly mounted on 2~ plates 94 and carry pivot pins 102 which are received within 2r~
1 the bored lugs 84 of mounting members 78 to support the members 2 78 for pivotal movement about horizontal axes on plates 9~, between the full line position and broken line position shown 4 in Figure 2. Threaded counterweights 104 are adjustably mounted on member 78 on threaded rods 104a and are employed to gravita-8 tionally bias the members 78 to the full line positions shown 7 in Figure 2.
9 With catcher members 78 in the full line positions shown in Figure 2, a pan being discharged from diverter section 11 22, as shown in Figure 1, is projected forwardly and downwardly 12 from the diverter sections 22 and 22a until its forward bottom 13 edge strikes and becomes supported upon the toe sections 90 of 14 the opposed catcher members 78. The cam member 92 of each catcher member 78 is located at the end of the member 78 lG (Figure 1) which is adjacent to the diverter section, and hence 17 during the initial approach of the pan to catcher member 78, 18 the bottom of the pan passes above and clear of each cam 19 section 92. To assist the pan in clearing the cam section 92, the ramp support 22a is located in the space between the end 21 of the diverter section 22 and the adjacent ends of catcher 22 member 78. The momentum imparted to the pan by diverter 23 section 22 drives the pan to the left as viewed in Figure 1, 24 until the left-hand or leading end of the pan strikes stop plate 28. At this time, the trailing end of the pan bottom 2~ has cleared diverter section 22 and ramp 22a and thus is en-27 tirely unsupported. The trailing end of the pan then drops 28 until its strikes the inwardly inclined cam portions 92 of the 2~ catcher member. The weight of the pan is sufficient to cause ~0 1 the pan to slide downwardly on these inclined cam sections 92 2 to thus swing the catcher members 78 outwardly to the broken 3 line position of Figure 2. This separating movement of the 4 adjacent opposed catcher members withdraws their support from the pan to permit the pan to drop freely between the now ~ spread catcher members 78 onto support fingers 34 of the first 7 stage support mechanism 30. As soon as the pan has passed be-8 low the catcher members 78, by the lowering movement of the g first stage support mechanism as described above, the counter-weights 104 gravitationally bias the catcher members back into 11 their pan receiving position.
13 FIRST ST:~OE SUPPORT ~C:~NIS~I
14 The main frame of the first stage support mechanism 30 is of generally U-shaped configuration when viewed from 1~ above and includes a pair of spaced parallel side members 108 17 each of which, referring to Figure 2, has bracket plates 110 18 fixedly secured to one end, the bracket plates 110 being fixedly 19 secured to each other by a transversely extending channel shaped frame member 112. As best seen in Figures 1 and 2, the 21 horizontally projecting side frame members 108 are each pro-22 vided with a pair of spaced lugs 114 which serve as a pivotal 23 support for finger frame assemblies 116, the finger frame ~4 assemblies 116 including a horizontally extending frame member 25 118 (Figure 2) which is pivotally supported at opposite ends 26 in lugs 114 as at pivots 120. Each finger frame assembly 116 ~7 further includes a pair of upright frame members 122 fixedly ~8 secured at their lower ends to member 118 and at their upper g~
~0 Z73~ ~
1 ends to a horizontally extending cross member 124 upon which 2 the support fingers 34 are fixedly mounted.
4 Mechanism for swinging fingPr frame assemblies 116 about pivots 120 between the pan supporting position shown ~ in full line in Figure 1 and the stack clearing position 7 indicated in broken line in Figure 1 includes a hydraulic 8 motor 126 whose cylinder is pivotally mounted upon a bracket 9 128 fixedly secured to one of the frame hrackets 110. The piston rod 130 of motor 126 is pivotally connected as at 132 11 (Figure 2) to the central portion of a link 134. One end of 12 link 134 is pivotally mounted as at 136 upon cross frame mem-13 ber 112, the pivot 136 being constituted by a shaft 138 which, 14 (see particularly Figure 3), extends transversely of the ma-chine and supports a second link 134a, identical to link 134.
1~
17 As best seen in Figure 3, the ends of links 134 and 1~ 134a remote from their common supporting shaft 138 are formed 19 with outwardly projecting universal joint extensions 142, 142a, which serve as pivotal mounts for drive links 146, 146a. Re-21 ferring to Figure 2, drive link 146 is pivotally connected at 22 its lower end as at 150 to crank arm 152 (see Figures 1 23 and 3) which is fixedly secured to and projects outwardly 24 from finger frame 116. As best seen in Figures 1 and 3, a similar connection is made from link 146a to the finger frame 26 at the opposite side of the machine.
28 Referring first to Figure 2, it is seen that if 2~ hydraulic cylinder 126 is actuated to retract its piston rod 1 130, link 134 (and link 134a) will be swung downwardly about 2 pivot 136, thereby driving the outer ends of these two links 3 downwardly to drive drive links 146 and 146a downwardly. Re-4 ferring now to Figure 1, it is seen that if the links 146 and 146a are driven downwardly, downward movement of crank arm ~ 152, rigidly secured to the finger frame 116, will cause 7 finger frame 116 to pivot outwardly about its pivot 120 to 8 swing the support fingers 34 on the opposed finger frames 116 9 outwardly away from each other to the retracted configuration indicated in broken line in Figure 1. Subse~uent extension 11 of the piston rod 130 of drive motor 126 will drive the finger 12 frames back toward each other to the full line position shown 13 in Figure 1.
The control circuit is so arranged that movement of 1~ the finger frames 116 from the article supporting position to 17 the outward stack clearing position is accomplished when the 18 first stage support mechanism 30 has reached its lower end 19 limit of movement. A control circuit, in a manner to be described hereinafter, maintains the finger frames in their 21 outwardly spread, inoperative positions while the first stage 22 support assembly 30 is returned to its upper elevated posi-23 tion. Actuation of motor 126 to restore the finger frames 24 to their article supporting position is initiated in the control circuit in response to the lowering of the second ~6 stage support mechanism 32 to its lowered, stack discharging ~7 position.
~8 SECOND STAGE :SUPPORT MECEANISM
As previously described, frame 58 is guided in ~0 1 vertical movement on the main machine frame as by rollers 60 2 guided in tracks 62. Hydraulic motor 64 whose piston rods 66 3 carries a pulley 68 engaged with a cable 70 is employed to raise 4 and lower frame 58 relative to the main machine frame.
Frame 58 further supports a pusher 76 (Figure 3) B slidably supported on frame 58 for movement from left to right 7 or vice versa as viewed in Figure 2. As best seen in Figures 8 1 and 3, pusher 76 moves laterally across the central portion 9 of the supporting surface defined by rollers 54. The pusher is coupled to a chain 156 operatively trained about a pair of end 11 sprockets 158, 160 which are rotatably mounted on the frame 58 12 of mechanism 32. A drive motor 162 is mounted upon frame 58 13 and is coupled through a chain and sprocket mechanism designated 14 generally 164 to drive sprocket 158.
15 After support of a stack of pans has been transfe~ed .
18 to the second stage support mechanism 32, with the mechanism 17 32 located in its elevated position shown in full line in 18 Figure 1, the support platform defined by rollers 54 is 19 lowered in step-by-step movement in synchronism with the addition of pans to the stack as detected by electric eye El.
21 The control system is normally set to indicate the completion 22 of a stack of a selected number of pans by the engagement of 23 frame 58 with the striker of a limit switch mounted on the ~4 main machine frame F at an appropriate el.evation, this eleva-tion being located at some distance above a lower limit of 26 movement of second stage mechanism 32. Upon the loading of 27 the final pan into the stack supported upon second stage ~8 mechanism 32, the control circuit transfers control of the 2~
~0 1 second stage mechanism motor 64 from electric eye ~1 and causes 2 the motor to drop mechanism 32 in continuous movement to its lower end limit of movement. The purpose of completing the 4 stack before mechanism 32 has reached its lower end limit of movement is so that the assembly of a second stack of articles ~ can commence during that period of time while the completed 7 stack is being discharged from the apparatus. The control cir-8 cuit is so arranged that when the stack is completed and the 9 second stage mechanism begins to drop in continuous movement toward its lower end limit of movement, motor 126 of the first 11 stage mechanism, which is at this time at its upper end limit 12 of movement with its support fingers retracted, is operated to 13 drive the support fingers 34 into their article supporting 14 position so that the pan following the final pan of the com-pleted stack into the apparatus becomes the first pan of the ~ next stack. Assembly of the second stack thus commences while 17 second stage mechanism 32 is carrying the completed stack to 18 the lower end limit of movement for subsequent discharge by 19 appropriate actuation of motor 162 to translate pusher 76 across a platform defined by rollers 54 to discharge the com-21 pleted stack from the machine. As soon as the stack is dis-22 charged, pusher 76 is retracted and second stage mechanism 32 23 is returned to its upper end limit of movement to await receipt ~4 of the stack being formed at this time on the first stage support mechanism.
~6 CONTROL SYS~EM
27 In a typical electrical control system, first stage ~8 motor 42, second stage motor 64, finger actuating motor 126 and pusher actuating motor 162 are respectively actuated by ~0 2~
1 solenoid operated four-way reversing valves employed in a con-2 ventional manner to make the appropriate connections between 3 the respective motors and a source of ~luid pressure and sump.
4 Energization of the various valve actuating solenoids is accom-plished by an electric control circuit which includes various ~ limit switches, electric eye detectors, and counters to initiate 7 the appropriate control actions in response to the movement of 8 articles or various parts of the apparatus. Preferably, a 9 programmable controller such as the Mini-PMC programmable con-troller sold by Allen Bradley Co. under catalog No. 1755A
11 is employed in the electrical control circuit. Such controller 12 can readily be programmed in a relatively simple manner to per-13 form a wide variety of control functions.
For purposes of explanation, however, an extremely 1~ simplified form of electrical control circuit is shown in 17 Figure 5 to indicate the manner in which control circuit 18 functions.
As an initial starting condition, it will be assumec 21 that parts of the apparatus are in the positions shown in full 22 line in Figure 1 of the drawings. In this condition, the first 23 stage support mechanism 30 is at its upper end limit of move-24 ment, with support fingers 34 being located in their inner pan supporting position. Second stage support mechanism 32 is 26 likewise located at its upper limit of movement, with pusher 27 member 76 in its retracted, inoperative position.
~8 2~ In the exemplary form of control circuit illustrate~
l limit switches LSl and LS2 (Figure 1) are mounted on the ma-2 chine frame to have their strikers depressed when flrst staye mechanism 30 is in its "up" position (LSl) or its "lower"
4 position (LS2). Referring to Figure 2, limit switches LS3 and S LS4 are located on the main frame 36 of first stage mechanism B 30 to respectively detect the finger frame 116 position when 7 the fingers are "in" (LS3) or "retracted" (LS4). Limit switches 8 LS5 and LS6 detect the position of the second stage support ~ mechanism 32 at its "upper" (LS5) or "lower" (LS6) position.
Limit switch LS7 is mounted on the machine frame to be engaged 11 by the second stage mechanism when the stack of pans supported 12 on the second stage mechanism reaches a predetermined height.
LS7 may be mounted for vertical adjustment on the machine frame 14 to select the number of pans to be included in a stack. A
limit switch LS8 is mounted on the discharge conveyor (not lB shown), which receives the stack of pans ejected by pusher 17 mechanism 76, actuation of the striker of limit switch LS8 18 signaling the fact that the stack of pans has been discharged l9 clear of the stacking apparatus.
21 With the first stage raised and support fingers 34 22 in their "in" position, and second stage mechanism 32 at its 23 "elevated" position with pusher 76 retracted, energization of 24 the control circuit by actuation of a suitable start button (not shown) conditions the control circuit to commence a stack-26 ing cycle.
~7 28 The pans are fed by the infeed conveyor onto diver~
2~ section 22 which feeds the pan into catcher mechanism 26 which, ~0 1 as described above, drops the first pan onto the support 2 fingers 34. As the pan drops onto fingers 34, it blocks the 3 light beam from light source Ll to electric eye El, thus 4 closing the contacts Ela of the control circuit of Figure 5.
Closure of contacts Ela completes a circuit through solenoid ~ SOlD between supply lines Ll and L2 via contacts LS3a (closed 7 because the fingers are in their "in" positions) and normally 8 closed contact LS2a which are closed at this time because the 9 first stage mechanism is not at its lower position. Solenoid SOlD positions the valve controlling the first stage lift 11 motor 42 to cause motor 42 to index the first stage mechanism 12 32 downwardly until the pan supported on fingers 34 clears 13 the electric eye beam, at which time contacts Ela open to 14 deenergize solenoid SOlD.
1~ A similar cycle is repeated as successive pans are 17 fed into the apparatus and added to the stack until the first 18 stage mechanism reaches its lowermost position. When the 19 first stage mechanism reaches its lower limit of movement, the striker of limit switch LS2 is engaged and actuated to 21 close contacts LS2b and to simultaneously open normally 22 closed contacts LS2a.
24 Closure of contacts LS2b energizes solenoid SOFO via contacts LS5a, which are closed at this time because second 26 stage mechanism 32 is at its upper limit of movement and 27 the striker of limit switch LS5 is actuated. Solenoid SOFO, ~8 when energized, actuates the finger frame operating motor 126 2~ to retract its piston rod, thereby swinging the fingers 34 clea~
~0 1i ~.Z4~1 1 of the stack to the broken line positions shown in Figure 1.
2 When the fingers are fully retracted, contacts LS3a are opened 3 and contacts LS4a are closed. closure of contacts LS4a con-4 ditions solenoid S02D to be energized under the control of electric eye contacts Ela via normally closed contacts LS6a, ~ which are closed at this time because the second stage mechanism 7 is not at its lower end limit of movement. Solenoid S02D, 8 when energized, causes the second stage lift motor 64 to lower 9 the second stage. With contacts LS4a and LS6a closed, the cyclic interruption of the electric eye beam by pans being 11 added to the stack actuates the electric eye contacts Ela which 12 now cyclically actuate solenoid S02D to actuate the second 13 stage lift motor 64 in downward indexing movement as pans are 14 added to the stack.
1~ When the second stage mechanism is lowered to a 17 position indicating the stack to be complete, the second stage 18 mechanism actuates limit switch LS7 to close contacts LS7a 19 which energizes a lock-in relay Rl via normally closed contacts LS6b, closed at this time because the second stage is not at 21 its lower end limit of movement. When relay Rl is energized, Z2 it closes contacts Rla which bypass the electric eye contacts 23 Ela and contacts LS4a to maintain solenoid S02D energized, 24 causing the second stage mechanism to be continuously lowered by the second stage lift motor 64 until the second stage 26 reaches its lower end limit of movement, at which time contacts ~7 LS6a and LS6b open to deenergize solenoid S02D and relay Rl.
~8 Contacts Rla also lock in relay Rl during this downward move-2~ ment of the second stage.
~0 iL~.Z~7~
1 When support fingers 34 are retracted by the pre-2 viously described actuation of the finger positioning motor 3 126, contacts LS4b close, as soon as the fingers 34 are fully 4 retracted, to energize solenoid SOlU via normally closed con-tacts LSlb to actuate the first stage lift motor 42 to raise ~ the first stage support mechanism 30 to its upper limit of 7 movement. When the first stage mechanism reaches its upper 8 limit of movement, contacts LSlb open to deenergize solenoid 9 SOlU. Fingers 34 remain in their retracted stack clearing position until limit switch LS7, as described above, is 11 actuated by the second stage mechanism upon the completion 12 of the assembly of the stack.
14 At the completion of the stack, contacts LS7c are closed, and contacts LSlc are likewise closed at this time 16 because the first stage is back at its upper position.
17 Closure of these latter two contacts energizes solenoid SOFI
18 which actuates to return fingers 34 to their inner stack 19 supporting po~itions to catch the next subsequent pan fed into the machine to begin forming a second stack while the 21 second stage mechanism is being lowered to its lower end 22 limits of movement to discharge the assembled stack from the 23 apparatus. A control relay R3 is connected in parallel with ~4 solenoid SOFI to lock the finger positioning solenoid SOFI
in its energized position via contacts R3a and normally closed 26 contacts LS2c, which are closed at all times when the first ~7 stage mechanism is away from its lower end limit of movement.
2~ When the second stage mechanism reaches its lower ~0 2'7~
8 end limit of movement, contacts LS6c are closed to energize 3 motor 162 of the pusher mechanism via solenoid SOBO to actuate 4 pusher 76 to push the completed stack from the lowered second stage mechanism. When the stack finally clears the apparatus, ~ it actuates limit switch LS8 to open normally closed contacts 7 LS8a, thereby deenergizing the pusher out actuating solenoid, 8 and simultaneously closing contacts LS8b. Closure of contacts 9 LS8b simultaneously energizes solenoids SOPR, S02U, and a lcok-in relay R4. Solenoid SOPR, when energized, actuates the 11 pusher motor to retract pusher 76 to its normal inoperative 12 position. When the pusher reaches its inoperative position, 13 it actuates a limit switch LS9 to open contact LS9a to de-14 energize solenoid SOPR.
1~ Solenoid S02U, when energized, conditions the second 17 stage lift motor 64 to stroke upwardly to return the second 18 stage mechanism to its normal upper position. Solenoid 19 S02U remains energized until the second stage mechanism arrives at its uppermost position, at which time limit switch 21 LS5 is engaged to open its normally closed contact LS5b to 22 deenergize solenoid S02U and a lock-in relay R4. Lock-in 23 relay R4, when energized, closes lock-in contacts R4a which ~4 bypass contact LS8b to maintain solenoids SOPR and S02U
energized in the event the ejected stack should move beyond ~6 the stack clear detecting limit switch LS8 before the pusher ~7 is fully retracted and the second stage has been returned 28 to its uppermost limit of movement.
~0 7~L
1 As described above, a second stack is being formed 2 on the first stage mechanism, from that point in the cycle 3 described previously when the first stack is completed and 4 the second stage, with the completed stack, begins to move toward its lower end limit of movement for the subsequent ~ discharge of the stack and the restoring of the second stage 7 to its original upper end limit of movement.
9 Also provided in the circuit (see the lower end thereof) are solenoids A and B which are the advance and re-11 tract solenoids respectively for the conventional cylinder 25 12 controlling diverter conveyor 22. The eye E has contacts Ea 13 and Eb in series with the solenoids A and B respectively 14 and a conventional timer T in series with contacts Rla of eye E' has contacts Tl and T2 also in series with the solenoids 1~ A and B respectively. Timer contacts Tl in series with 17 solenoid A, and T2 in series with solenoid B, will not be 18 operated unless the timerT is energized for a predetermined 19 period, i.e. one and one-half seconds to indicate that pans have piled up on conveyor D and future pans proceeding to 21 conveyor 22 should be stacked. Moreover, so long as the eye E
22 light path is broken by a pan on conveyor 22, the conveyor 22 23 cannot be moved so that any pan in a forward position on 24 conveyor 22 discharges from conveyor 22 before conveyor 22 shifts. Assuming conveyor 22 is in the up (broken lines) 26 position, pans feed along conveyors 94 and D and eye E' is 27 now blocked for a long enough period to change the position ~8 of conveyor 22. When pans pile up on conveyor D the eye E' 2~ will be blocked for a longer period than the predetermined ~0 .Z~271 1 period chosen and contacts Tl and T2 will open and close 2 respectively. Assuming eye E is not at the time blocked, 3 solenoid A will be deenergized, and solenoid B energized to 4 shift conveyor 22 to the down position. Timer T is an auto-matically resetting timer. The gap forward of conveyor 22 ~ is selected with respect to the length tcenter of gravity) 7 of the pans P such that a continuous flow of pans P can be 8 maintained regardless of the position of conveyor 22.
The exemplary control circuit illustrated, of ll course, for the sake of clarity, omits many conventional 12 elements employed in the actual machine, such as manual in~
13 ¦ dexing buttons which can be employed to manually position 14 the various elements as desired. Moreover, it is to be under-stood the positions of the various limit switches can be ad-16 justed to process either bread or bun pans.
l9 The manner in which articles are stacked is schema-tically illustrated in sequential views in Figures 6-12.
22 Referring first to Figure 6, portions of the first 23 stage mechanism 30 and second stage mechanism 32 are shown 24 in the positions occupied at the commencement of a stacking operation. Both of the first stage mechanism 30 and second ~6 stage mechanism 32 are located in their uppermost limit of ~7 movement with the first stage mechanism 30 located in its ~8 operative position with fingers 34 in their inner pan re-2~ ceiving position. Pans P to be stacked are being fed to the ~0 .Z~27~
1 apparatus by infeed conveyor 20 and diverter section 22 with 2 the first pan P of the stack being shown in Figure 6 just as 3 it is striking fixed stop 28. For purposes of clarity, the 4 gravity operated catcher mechanism 24 has not been shown in the schematic views.
7 In Figure 7, the apparatus is shown with a first 8 group of pans assembled into the partial s~ack Sl supported 9 upon the first stage mechanism 30 which, as compared to the position shown in Figure 6, has been indexed to lowered 11 positions to keep the uppermost pan in the stack Sl below 12 the path of movement of subsequent pans P into the stack.
14 In Figure 8! first stage mechanism 30 has been lowered to its lowermost limit of movement, and the support 16 of the partial stack of pans Sl has been transferred to 17 second stage mechanism 32. The first stage mechanism has been 18 actuated to retract its fingers 34 clear of the partial stack 19 Sl. As indicated in Figure 8, pans P continue to be fed into the apparatus.
22 In Figure 9, the apparatus is shown at the instant 23 the final pan PA of a stack is striking fixed stop 28. As 24 compared to Figure 8, it will be observed that the first stage mechanism 30 is, at this time, located at its upper limit of 26 movement, however, the support fingers of the first stage 27 mechanism are still retracted clear of the stack. The next au S sequent pan PB is just entering diverter section 22.
7~
1 In Figure 10, the second stage mechanism is being 2 lowered in continuous movement, and the first stage mechanism has returned to its inner pan supporting position in time to 4 receive the first pan PB of the next subsequent stack to be formed. The completed stack Sl is being lowered in con-tinuous movement by second stage mechanism 32 to the outfeed r conveyor 32'.
9 In Figure 11, the second stage mechanism has been lowered to its lower limit of movement and the completed 11 first stack is being pushed by pusher member 76 in a direction 12 away from the observer in Figure 11 onto outfeed conveyor 32'.
While the first assembled stack Sl is discharging, it will 14 be observed that a partial second stack S2 is being assembled on first stage mechanism 30.
17 In the next sequential view of Figure 12, the first 18 assembled stack S1 has been removed from the apparatus by 19 outfeed conveyor 32' and the second stage mechanism 3 has been returned to its upper limit of movement where it awaits 21 receipt of the second partial stack S2 being assembled on 22 the first stage mechanism. The views of Figures 7 and 12 23 show essentially the same stage in the stack forming operation 24 and the apparatus continues to cycle from the Figure 7 -Figure 12 stage through the successive steps shown in Figures 26 8, 9, 10, 11 and 12.
~8 With the apparatus, high average stacking rates in 2~ the neighborhood of 50 pans per minute are feasible and the l~.Z~Z'^~l 1 fast-acting, low inertia diverter system (22 etc.) can direct 2 pans to the stacking mechanism or to an overhead conveyor without having to stop the flow o pans. Because the catcher 4 26 which initially receives the pans for stacking is self-releasing, it can operate at a faster rate than a stacker ~ which employs a motor operated releasing system, and in which 7 rate of stack time is sacrificed because of the time delay 8 necessary to the operation of sensors and motors. For example, 9 a motor operated pan-catcher might conceivably take 3/lOths of a second more to operate and this cumulatively would 11 clearly restrict the rate of operation of the stacking machine.
12 Moreover, the gravity operated catcher described is smoother 13 in operation and does not have the problem of the rapid wearing 14 of fast-operating drive linkage.
lB The present system is also versatile. For instance, 17 the full dead weight of each pan being processed is counter-18 balanced out, so that essentially cam leverage causes the 19 opening of the catcher arms. Thus, a range of pans of different weight can be handled without changing anything, 21 because it is the dead weight of the entire pan which is 22 counter-balanced out and the full weight of the pan is never 23 a factor until the tail end of the pan drops to the catcher 24 pan mechanism. Finally, it is the kinetic energy of the 25 ¦ falling pan acting through the cam leverage which causes the 26 ¦ catcher arms 78 to open. In this sense, the catcher is some-27 ¦ what insensitive to weight and permits a good range of pan ~8 ¦ weights to be handled without ad~ustment of the counter-weights 2~ 104 along rods 104a. For example, pans in the range of 18 ko ~0 ~:I.Z4Z7,.
l 32 inches long, and 8 to 32 inches wide, and weighing 8 to 2 15 pounds can be readily handled. Moreover, the system can 3 be switched from bread pans to bun pans of various heights 4 with no lost time between the completion of one stack of pans and the start of another stack except for any time required 6 for adjusting to any pan length and width changes. Moreover, 7 the system can stack aluminum pans because no magnets are 8 required and pans which are either right-side up or upside 9 down. Minimum machine adjustments are required for pan di-$0 mension variations and the machine is a very low maintenance ll machine.
13 While one embodiment of the invention has been 14 described in detail, it will be apparent to those skilled in the art that the disclosed embodiment may be modified. There-l~ fore, the foregoing description is to be considered exemplary 17 rather than limiting, and the true scope of the invention i5 2~ t t defined in the following claims.
~6 ~8 2~
~0
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a pan stacking apparatus having pan sup-port means for lowering pans in a stack along a fixed vertical path, and feeding means for feeding pans in succession to a receiving location on said fixed path for addition to the top or said stack; the improvement wherein said feeding means comprises pan conveying means having a downwardly inclined discharge end for receiving a pan adjacent said receiving location and moving it on an inclined path out beyond said end with its trailing end supported by the discharge end, a catcher operable to receive and support the front end of a pan discharged from said conveying means, said pan passing from said infeed means to said catcher along a downwardly inclined path; and cam means mounting said catcher for self-releasing movement when the weight of the trailing end of the pan is released from the convey-ing means to shift said catcher outwardly away from said pan and drop said pan from said receiving location; said cam means being located at the end of said catcher closest to said infeed means and lying below said inclined path.
2. The combination of claim 1 wherein the catcher comprises a pair of opposed members defining opposite sides of the receiving location in one position and being movable to pan releasing positions outward thereof; and adjustable means normally biasing said opposed members to said one position.
3. In an article stacking apparatus having article support means for lowering articles in a stack along a fixed vertical path, and feeding means for feeding articles in succession to a receiving location on said fixed path for addition to the top of said stack; the improvement wherein said feeding means comprises article conveying means having a discharge and adjacent said receiving location, a pair of spaced guide members defining opposed sides of said receiv-ing location operable to engage and support opposed sides of an article discharged from said conveying means, and self-releasing means on said guide members operable when engaged by an article to shift said guide members outwardly away from said article to drop said article from said receiving location, said conveying means comprising an end section inclined downwardly to said discharge end, said guide mem-bers comprising elongate members of generally L-shaped trans-verse cross section supported for pivotal movement about parallel horizontal axes extending along the upper end of the L section, said members being gravitationally maintained in a position wherein the vertical legs of the L section slid-ably engage opposite sides of an article discharged from said conveying means and the horizontal legs of the L section under-lie the bottom of the article, said horizontal legs being spaced below the discharge end of said conveying means where-by the forward end of an article being discharged from the inclined end section of said conveying means engages and slides along said horizontal legs, and said release means comprising an inclined plate means extending between the distal ends of said L section at the ends of said members adjacent said discharge end to be engaged by the trailing end of said article as the article leaves said end section of said conveying means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA386,535A CA1124271A (en) | 1978-09-25 | 1981-09-23 | Pan stacking system |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA311,983A CA1110670A (en) | 1978-09-25 | 1978-09-25 | Pan stacking system |
| CA386,535A CA1124271A (en) | 1978-09-25 | 1981-09-23 | Pan stacking system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1124271A true CA1124271A (en) | 1982-05-25 |
Family
ID=25668769
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA386,535A Expired CA1124271A (en) | 1978-09-25 | 1981-09-23 | Pan stacking system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1124271A (en) |
-
1981
- 1981-09-23 CA CA386,535A patent/CA1124271A/en not_active Expired
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