US3548995A - Controlled variable speed stacking device for publication conveyor - Google Patents

Description

United States Patent [72] Inventors Samuel Oderman Corona Del Mar; Raymond L. Wiseman, Santa Ana; George T. Rushforlh, Mission Viejo, Calif. [21] Appl. No. 736,673 [22] Filed June 13, 1968 [45] Patented Dec. 22, 1970 [73] Assignee Sta-Hi Corporation Newport Beach, Calif. a corporation of California [54] CONTROLLED VARIABLE SPEED STACKING DEVICE FOR PUBLICATION CONVEYOR 20 Claims, 5 Drawing Figs.

[52] [1.8. CI. 198/20, 93/93; 271/88; 198/35.198/40 [51 Int. Cl. 865g 47/00 [50] Field of Search 198/20, 35, 37, 82; 93/93(.3); 271/88 [56] References Cited UNITED STATES PATENTS 3,418,895 12/1968 Palmer 93/93(.3)UX

3,429,239 2/1969 Murchison etal.

ABSTRACT: A series of support members are driven in a continuous path downwardly through a stacking region to a lower end thereof and then upwardly to return to an upper end thereof. During the support member movement through the stacking region, publications are received from a more or less continuous stream building stacks thereon for deposit at the stacking region lower end. Sensing means senses the stack upper extremity during stack buildup and controls the feed of downward movement of the particular support member to maintain the stack upper extremity within a predetermined vertical distance range from the stacking region upper end during said stack buildup. Also, the sensing means may include a safety switch arranged to override other control and temporarily provide maximum speed of support member downward movement in the event the stack upper extremity reaches a predetermined maximum vertical position during stack buildup.

PATENTEU minzzlsm 4 3 548 995 SHEEI Inf 4" INVENTO/QS SAMUEL ODERMA/V, RA YMOND L. M/ISEMAN, GEORGE 7. RUSHFOETH MAHOA/Ey & Ham/54x52 ATTORA/EYfi PATENTED 0513221970 3Q 548L995 SHEET 2 0F 4 RA YMONO L. W/sEMA/v, GEORGE TRusHFaQTH MAHOAEY & HOR/VBA KB? PATENTED DEEZZIBYB 3548395 3A MUEL ODEEMAN, RA YMOA/D L. VV/SEMAN, GEORGE Z RUSH/ 02 TH MA HONEY & Ham/amaze ATTORNEY? caoss REFERENCETO RELATED APPLICATION A preferred embodiment of the principles of the present invention is illustrated and describedherein incorporated in a unique form of stacking device separately described and claimed in our copending application, Ser. No. 717,231 filed Mar. 29, 1968, now US. Pat. No. 3,525,170 entitled AUTO- MATIC STACKING DEVICE FOR PUBLICATION CON- VEYOR, and reference is made herein tosaid copending application for certain of the working details of said stacking device.

BACKGROUND OF THE INVENTION ing generalcharacter incorporating a unique speed control device controlling the speed of downward movement of each of the support members during the publication stack building thereon so as to coordinate the speed of support member downward movement withthe speedof stack buildup and always maintain the upper extremity of the particular stack during said buildup within. a predetermined vertical distance range of the continuous stream of publicationsbeing intercepted by that support member. As a'rsult, the principles of the present invention make possible the building of publication stacks on the moving support members in a much more perfectly arranged and orderly stack than has ever been heretofore possible with prior stacking devices, despitethe required high-speed operation of said stacking devices.

- Certain prior forms of stacking devices for publication conveyors have heretofore been provided'wherein only a single reciprocating stack support member or platform'is used. In this case, the platform inserts generally horizontally into the stacking region for intercepting a more .or less continuous imbricated stream ofincoming publications and for the building of a stack thereon, drops vertically to deposit said stack for outfeed automatic or hand removal, andthen returns vertically for reinsertion horizontally. Obviously, with the inherent depositing or unloading and reinsertion-return time delays, such support member reciprocating form isextremely limited in speed and stack reception capabilities.

Various other prior forms of stacking devices for publication conveyors have heretofore been" provided of a type more closely capable of building publication stacks from a relatively continuous high-speed stream of such publications, and these have included a series of some form of-support member movable downwardly through a stacking region for intercepting the continuous stream of imbricated publications for the building of publication stacks thereomFurthermore', all of said prior stackingdevices of this type, to our knowledge,'with the exception of the particular embodiment of stacking device illustrated and described in our said copending application Ser. No. 717,231, have been constructed with the series of support members simultaneously movable through a single drive system and motor. The usual pattern of support. member movement is to commencer'novement of one of the support members downwardly through the stacking region intercepting the continuous stream of imbricated publications and building a stack thereof on said support member while the next support member is simultaneously moved toward a position at the stacking region upper end in order to be ready to intercept the publication stream immediately upon the previous support member stack being completed.

In order to provide proper interception of the publication stream by the succeeding support member upon completion of the desired stack on the preceding support member, keeping in mind that the infeeding stream of publications is continuous and at extremely high speed, most prior stacking devices have operated with a stop and start pattern of-movement of the simultaneously movable support members,'that is, upon the commencement of the building of a publication stack on a preceding support member, said preceding support member is moved quickly downwardly within the stacking region and the succeeding support member is, at the same time, quickly moved to an upper end of the stacking region. When such succeeding support member reaches stacking region upper end, movement of all of the support members is stopped so that said succeeding support member-is poised ready for entrance into the stacking region and interception of the publication stream when the stack on the preceding support member is completed. Also, again due to the extreme highspeed'movement of the infeeding publication stream, certain of the prior stacking devices have included-some form of preloading of the support member poised at the stacking region upper end so that said support member can be started in motion downwardly in a high-speed snap movement in order that perfect publication stream interception will take place even though the publications in the infeeding stream are moving at the high speed and the leading publication edges are only overlapped or offset a matter of a few inches.

Now, the foregoing factors discussed might not present any great problem if all further factors of individual publication thickness, finished publication stack height, infeeding publication stream speed and overlap of the infeeding publications would remain exactly constant from one overall stacking operation to the next and even in a single overall stacking.

operation. Unfortunately, however, this is obviously not the case since, even in an individual overall stacking operation and even where the finished stacks are to contain the identical number of publications therein, merely slight variations in the distance of overlap of the publication in the infeeding stream and slight gaps in said stream can appreciably interrupt the smooth pattern of constant speed infeed publication flow. Furthermore, equally if not more important is the fact that one printing run of publications will vary from the next so that the thickness of publication will vary from one run to the next varying publication stacks of equal number accordingly.

With the prior constructions of stacking-devices, therefore, with all of the various compounding factors of speed and size variation, it is necessary to move one support member into the upper end of the stacking region for intercepting the infeeding,

publication stream and also move 'said support member quickly downwardly within the stacking region during a buildup of the stack thereon in order that the succeeding support member may reach the stacking region upper end and be preloaded ready for snap entrance and interception of the publication stream prior to the stack then in the building stage being completed. In order to accomplish the same with adequate safety factors to allow for the variations involved, the support member upon which the publication stack is being built must move downwardly within the stacking region well ahead of. the infeeding publication stream and be stopped intions entering the stacking region to drop freely downwardly an appreciable distance for reaching the stack upper extremity with consequent disarrangement of the stack. buildup.

With proper constructions of drive and drive controls, it is possible with certain of the prior constructions to somewhat modify the foregoing problem through adjustment of the support member drive speed prior to the start of a given stacking operation. In other words, if each stack of the run is to be of 5 OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide a controlled variable speed stacking device for publication conveyors which completely solves the foregoing important problem by controlling the speed of movement of each support member during a stack buildup thereon exactly according to the speed of said stack buildup and maintain the upper extremity of the stack during said buildup within a predetermined vertical distance range of the infeeding stream of publications entering the stacking region. As a result, the upper extremity of a particular publication stack, during the buildup thereof, is maintained within an ideal vertical distance range of the infeeding publication stream entering the stacking region and throughout said stack buildup, despite all of the complex variables such as infeeding publication speed due to overlap variations and stream gaps, as well as variations in finished stack size, either in a given stacking run or between stacking runs. Consequently, the final publication stacks produced according to the principles of the present invention are of maximum uniformity and orderliness, far superior to that heretofore possible with the prior stacking devices. I

It is a further object of this invention to provide a variable speed stacking device for publication conveyors of the foregoing general character wherein sensing means is arranged for automatically sensing the speed of stack buildup on each support member as said support member progresses downwardly through the stacking region receiving the publications from the infeeding publication stream, said sensing means in turn automatically controlling the support member downward speed for maintaining the upper extremity of the particular stack being built within the predetermined vertical distance range of the infeeding publication stream. A preferred embodiment of the present invention includes variable electrical transducer means operable through a sensing member constantly engaged with the publication stack upper extremity during the buildup of said stack, movements of said sensing member creating variations in said transducer means. The transducer means is also electrically connected to electric drive means for the support members and arranged for variations in the transducer means to be translated into variations in electrical power to the electric drive means, thereby varying the speed of drive to the particular support member upon which the stack is then being built to perfectly control the location of the stack upper extremity during such buildup.

It is also an object of this invention to provide a controlled variable speed stacking device for publication conveyors including the foregoing sensing means controlling the operational speed thereof which may further include particular safety means to ensure against stacking device damage in the event of malfunctioning of the sensing means or an inordinate stack buildup of such rapidity that the sensing means cannot follow with sufficient speed. Such safety device may take on the form of a safety switch operable by the sensing member in the event the particular stack upper extremity reaches a maximum vertical position within the predetermined vertical distance range, said safety switch being operably connected for overriding or bypassing the control of the support member speed by the transducer means and automatically directing a maximum of electrical power to the electric drive means so as to drive said support member at a maximum speed downwardly. Such overriding control of the electric drive means by the safety switch is only of a temporary nature so that if the upper extremity of the stack being built returns to a safe vertical range, the transducer means will again take over normal varying speed control for the usual functioning of the stacking device according to the present invention.

Other objects and advantages of the invention will be apparent from the following specification and the accompanying drawings which are for the purpose of illustration only.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a stacking device incorporating an embodiment of the speed controlling sensing means of the present invention;

FIG. 2 is an enlarged, fragmentary, vertical sectional view of an upper portion of the stacking device of FIG. 1 looking in the direction of the arrows 2-2 in FIG. 3 and more clearly illustrating the particulars of the sensing means of FIG. I;

FIG. 3 is a fragmentary, sectional view looking in the direction of the arrows 3-3 in FIG. 2;

FIG. 4 is an enlarged, fragmentary, sectional view looking in the direction of the arrows 4-4 in FIG. 3;

FIG. 5 is a vertical sectional view looking in the direction of the arrows 5-5 in FIG. 1.

DESCRIPTION OF THE BEST EMBODIMENT CONTEMPLATED Referring initially particularly to FIGS. 1 and 5 of the drawings, a stacking device for publication conveyors is illustrated and includes a main frame generally indicated at 10 supporting an infeed conveyor section generally indicated at 12, a stacking section generally indicated at 1 4 and an outfeed conveyor section generally indicated at I6. Furthennore, the stacking device includes sensing means generally indicated at 18 forming an illustrative embodiment of the principles of the present invention supported on the main frame 10 between the inner termination of the infeed conveyor section 12 and the entrance into the stacking section 14. As hereinbefore stated, the general construction of stacking device illustrated is described and claimed in our said copending application Ser. No. 717,231 so that the same is only described herein in sufficient detail for a clear understanding of the principles of the present invention, with reference being made to said copending application for the more particular details of construction and operation of said stacking device.

As particularly shown in FIG. 1, the infeed conveyor section 12 is connected to a usual publication conveyor 20 for receiving therefrom a continuous stream of imbricated publications through said infeed conveyor section between usual upper conveyor belts 22 and lower conveyor belts '24. The infeed conveyor section 12, in turn, directs the continuous stream of imbricated publications slightly angularly downwardly into an upper end of a stacking region generally indicated at 26 forming a part of the stacking section 14. Without entering into a detailed description at this point, the continuous stream of imbricated publications is continuously and consecutively intersected by a series of publication stack support members generally indicated at 28 and movable in a continuous path around the stacking section 14 and particularly, downwardly through the stacking region 26 of said stacking section.

The interception of the continuous stream of imbricated publications by the support members 28 while the particular support member so intercepting continues to move downwardly through the stacking region 26, results in a generally vertical stack of publications being built on each of the support members 28. After a completed stack of publications has been built on a particular support member 28, continued downward progressive movement of said support member through the stacking region 26 ultimately results in each of the support members depositing its finished stack of i I More particularly tothe details of the stacking section 14 and still referring particularly'to FIGS. 1 and 5, said stacking section mounts the previously mentioned support members generally indicated at 28 which are actuallyformed by one set of two support members 36 separately movable from a second set of two support members 38. The support members 36-are mounted movable around the stacking section 14 individually alternately positioned relative to the supportmembers 38, that is, there being one of the support members 36 between each of the support members 38. Thus, one of the supportmembers.

36 may be positioned moving downwardly through the stacking region 26 of the stacking section 14 while the next consecutive of the support members -38'may be positioned at the stacking region upper end posed ready for entrance downwardly into said stacking region, or in the converse, one of the support members 38 may be moving downwardly through said stacking region while one of the support members 36 is poised ready for downward entrance into said stacking region, all to be explained more in detail below.

As best seen in-FlG. l, the sets of support members '36 and 38 are mounted movable about the stacking section 14 in the same continuous path downwardly through the stacking region 26 from theupper to the lower end thereof, then rearwardly from said stacking region lower end, then upwardly through a return region 40 displaced rearwardly from the stacking region and ultimately forwardly for return to the stacking region upper end. As partially shown in each of FIGS. 1 and 5, the support members 36 forming the first set are sup ported for such movement on apair of inner conveyor chains 42 engaged over upper and lower drive shafts 44 and 46 throughappropriate sprockets 48,. The support members 38 forming the second set are similarlysupp'orted over the upper and lower drive shafts 44 and 46 by a pair' of outer conveyor chains 50 engaged over appropriate sprockets S2.

ln order to accomplish the separaternovement of the first set of support members 36 and the second set of support members 38, the sprockets 48 for the inner conveyor chains 42 are secured to and movable with the upper'drive shaft 44, but journaled relative to the lower drive shaft 46, while the sprockets 52' for the outer conveyor chains 50 are joumaled relative to the upper drive shaft 44, but secured to and movable with the lower drive shaft 46. The upper drive shaft 44 is driven by a-variable speed, electric drive motor 54 through a power transmission connection formed by a series of drive chains 56, and the lower drive shaft 46 is driven by a variable speed, electric drive motor 58 througha power transmission connection formed by 'a series of drive chains 60. Thus, actuation of either of the drive motors 54 or 58 will separately move the respective of the support members 36 or 38 about the continuous path described on the stacking section 14, the speed of said drive being dependent on the amount of electrical power directed to that particular drive motor so that the speed of drive can be varied by varying the amount of electrical powerto that particular drive motor.

As clearly set forth in detailed description in our said copending application Ser. No. 717,231, each of the support members 36 and 38 is substantially identical being pivotally connected to the respective inner and outer conveyor chains 42 and 50 projecting therefrom generally in cantilever fashion. Furthermore, the support members 36 and 38 are maintained appropriately properly positioned particularly in their movement downwardly through the stacking region 26 by sets of guide rollers 62 movable in appropriate guide tracks 64 so that said support members during their downward movement through the stacking region project forwardly in generally horizontal directions for receiving stacks of publications thereon from the continuous stream of imbricated pu blications hereinbefore discussed. Still further, each of the sup port members 36 and 38 is formed by a series of transversely spaced tines 66 shown in FIG. 5, which,during downward movement of the support members through the stacking re gion 26 project forwardly through a: series of transversely spaced, stationary stack guide bars 68 secured to the stacking section 14.

Thus, as the support members 36 and 38 move progressively downwardly through the stacking region 26, they are guided in their forward projection of the tines66by the combination of the drive'chains 60, guide rollers 62 and guide tracks 64, the stacks of publications being built'th'ereon being rearwardly supported by the stationary stack guide bars 68. As the building of a stack of publications on each of the support members 36 and 38 is completed within the stacking region 26, the support members then move said stack on downwardly to the stacking region lower end adjacent the generally horizontal surface of the conveyor belt 30 on the outfeed conveyor sec tion 16. in the particular form of stacking device herein illustrated, the movable guiding of the supportrnernbers 36 and 38 is such that as the support members reach the lower end of the stacking region 26, said support members are rapidly withdrawn in a generally horizontal position rearwardly through the stack guide bars 68 so as to move from beneath the particular publication stack supported thereon and deposit said stack smoothly on the conveyor belt 30 or other conveying means of the outfeed conveyor section 16 for removal from the stacking device as also hereinbefore described.

At this point it is pointed out, as was also pointed out in our said copending application Ser. No. 717,231, that under certain circumstances and under certain conditions, it would not be necessary to have more than one support member 36 or 38 on each of the sets of conveyor chains 42.or 50 while still obtaining the majority of the advantages of the present inventions. It should be appreciated that such changes and alterations, as well as others, will be readily apparent to those skilled in the art and are fully contemplated herein and in the appended claims.

As is also described in detail in our said copending application Ser. No. 717,231, it is preferred that the stacking section 14 will include some form of'latchmeans including alatch plate 70 at the entrance to the upper end of the stacking region 26 for operably engaging each of 'thesupport members 36 and 38 so that particular support member is brought to and preferably stopped at the stacking region upper end. The purpose of this latch means is to preload each of the- support members 36 and 38 for snap entrance into the stacking region 26 to quickly and smoothly intercept the continuous stream of imbricated publications from the infeed conveyor section 12 when the desired stack building has been completed on the next preceding support member then travelling downwardly through the stacking region. Whether a particular support member 36 or 38 remains poised at the upper end of the stacking region 26 preloaded for snap entrance into the stacking region or whether it remains poised merely for normal entrance is not, however, vital to the improvements of the present invention.

More particularly to the improvements of the present invention,and referring to FIGS. 1 through 4, the sensing means generally indicated at 18 is mountedat the upper end of the stacking region 26 directly overlying the path of travel of the infeeding continuous stream of imbricated publications from the infeed conveyor section 12. The sensing means 18 includes an angularly and downwardly rearwardly projecting sensing arm 72 vertically pivotally connected to a frame 74 by a pivot plate 76 on a pivot shaft 78. The pivot plate 76 is resiliently urged through a spring 80 to, in turn, spring urge the sensing arm 72toward a maximum downward angular position, said maximum angular downward position being defined by engagement of a stop'portion 82 of the pivot plate 76 engaging a part of the frame 74.

The sensing means 18 further includes variable electric transducer means, in this case, in the form of a variable electric differential transformer 84 mounted on the frame 74 overlying an engagement recess 86 of the pivot plate 76 which extends rearwardly of the pivot shaft 78. A transformer control bar 88 is movably received in the differential transformer 84 in the usual manner and projects downwardly through the frame 74 into engagement in the recess 86 of the pivot plate 76, such engagement being spaced rearwardly of the pivot shaft 78. As a consequence, upward and downward pivotal movement of the sensing arm 72 will cause inward and outward movement of the control bar 88 within the differential transformer 84 to in turn, control the amount or characteristics of electrical power, in this case controlling voltage characteristics, transmitted through the differential transformer 84. More particularly, upward pivotting of the sensing arm 72 causing upward movement of the control bar 88 will, for simplified explanation, progressively increase the amount of electrical power transmitted through the differential transformer 84, and downward movement of the sensing arm will progressively decrease the amount of electrical power transmitted therethrough.

A safety switch in the form of a safety limit switch 90 is also mounted on the frame 74 rearward of the differential transformer 84 and overlying a rearward portion 92 of the pivot plate 76 spaced rearwardly from the pivot shaft 78. An actuating arm 94 of the limit switch 90 is engaged with an actuating pin 96 projecting a limited distance downwardly through the frame 74 toward the rearward portion 92 of the pivot plate 76, the lower end of said actuating pin being engaged by the pivot plate rearward portion and movedupwardly to actuate the limit switch 90 when the sensing arm 72 is moved to an extreme vertically upward position. The limit switch 90 is electrically connected in a usual and well-known manner for electrically bypassing or overriding the differential transformer 84 upon actuation of said limit switch to transmit a predetermined maximum electrical power around or bypassing said differential transformer. Thus, when the sensing arm 72 reaches said predetermined maximum vertical position and temporarily engaging the actuating pin 96, the safety limit switch 90 is temporarily actuated during the time the sensing arm remains in this maximum vertical position, thereby directing full power overriding the differential transformer 84 and eliminating the varying power control of said differential transformer.

Both of the differential transformer 84 and the safety limit switch 90 are electrically connected in a usual and well-known manner for in turn alternately controlling the direction of electrical power to the support member drive motors 54 and 58 during the time each of the support members 36 and 38 is moving downwardly from the upper end of the stacking region 26 and downwardly through said stacking region supporting a stack of publications being built thereon. In other words, when a particular support member 36 or 38 begins movement downwardly through the stacking region 26 and until a completed publication stack has been built thereon, that is, until the next succeeding support member is ready to begin downward movement into the stacking region 26 for inter cepting the publication continuous stream, the drive motor 54 or 58 for that particular support member has the electrical power being directed thereto controlled by the differential transformer 84 and the safety limit switch 90 of the sensing means 18. At the same time, in view of the angular extension of the sensing arm 72 of the sensing means 18, the publications entering the upper end of the stacking region 26 and being deposited downwardly on the particular support member 36 or 38 pass beneath the sensing arm so that said sensing arm remains constantly engaged with the uppermost of the publications on the publication stack being built and will pivot upwardly and downwardly according to upward and downward variations in the upper extremity of said stack.

The overall result is that during the building of each stack of publications on a particular of the support members 36 or 38,

the sensing means 18 constantly senses the speed of buildup of said publication stack relative to the speed of downward movement of the particular support member by constantly sensing, through engagement by the sensing arm 72, the relative vertical position of the stack upper extremity. Furthermore, due to the electrical power control of the transducer means, in this case, the differential transformer 84, the direction of electrical power to the appropriate drive motor 54 or 58 is constantly controlled for controlling the speed of the particular support member to maintain the upper extremity of the stack being built at all times within a predetermined ve rtical distance range of the upper end of the stacking region and, more important, within said predetermined vertical distance range of the infeeding publications from the infeeding publication continuous stream. As the upper extremity of the stack of publications being built moves upwardly causing the sensing arm 72 to move the control bar 88 of the differential transformer 84 upwardly, the electrical power directed to the appropriate drive'motor 54 or 58 will be increased to increase the speed of said variable drive motor and move the particular support member at a greater speed downwardly. If the stack upper extremity moves vertically downwardly during said stack buildup, the speed of the appropriate drive motor 54 or 58 is decreased in the same manner to decrease the speed of the particular support member.

If, however, through some malfunction or an inordinate feeding of the publications into the upper end of the stacking region 26 causes the stack buildup to move ahead of possible normal control by the differential transformer 84, the stack upper extremity can reach a maximum vertical height as determined by the sensing arm 72 engaging the actuating pin 96 of the safety limit switch 90. If such occurs, the safety limit switch 90 is actuated, bypassing or overriding the control of the differential transformer 84 and directing full maximum power to the particular drive motor 54 or 58 causing said drive motor to move the particular support member 36 or 38at a maximum speed downwardly to quickly correct and properly position the stack upper extremity. Once the vertical positioning of the stack upper extremity is corrected to a safe level, the temporary actuation of the safety limit switch 90 will, of course, cease by the downward movement of the sensing arm 72, but the effect of the safety limit switch is to obviously eliminate any danger to the components of the stacking device from the inordinate stack buildup.

As hereinbefore described, the sensing and variable control of the upper extremity of the publication stack being built is obtained through the use of differential transformer 84 for maintaining variable speed control of the particular support member 36 or 38 during said stack buildup, but is is clear that this differential transformer is only one form of transducer means which could be applied to the same function and it is not intended to limit the principles of the present invention to the exactconstruction shown. Furthermore, although the particular stacking device illustrated and described herein includes separately movable consecutive support members 36 and 38, the sensing means 18 of the present invention could be applied to consecutive, simultaneously movable support members driven by the same drive motor for controlling at least the major portion of the stack buildup on said support members andeven though the support members simultaneously move in a stop-start pattern. The major portion of the advantages of the present invention would be obtained in this latter situation for obtaining a more orderly publication stack during the major portion of the building thereof.

According to the principles of the present invention, therefore, a controlled variable speed stacking device for publication conveyors is provided wherein the speed of stack buildup thereon is constantly sensed and the speed of the stacking device is automatically regulated to maintain the upper extremity of the stack being built within a predetermined vertical distance range of the infeeding publications forming said stack, thereby resulting in more orderly arranged stacks from said stacking device than has heretofore been possible with prior constructions. Also, the sensing means providing the foregoing advantages includes safety means incorporated therein for overriding the usual functioning of the sensing means and driving the stacking device at maximum speed in the event of some malfunction creating a danger of damage to said stacking device.

Weclaim:

1. In a stacking device of the type used in a publication conveyor system and having a main frame mounting a series of spaced stack support members movable in a continuous path downwardly through a stacking region to a stacking region lower end and then upwardly through a return region displaced from said stacking region to a stacking region upper end, infeed conveyor means operably associated with said main frame for feeding a continuous streamof publications to said stacking region upper end and depositing said publications into generally vertical stacks on said support members means operably connected to said drive means and positioned 7 relative to said stacking region upper end for directly sensing an upper extremity'of each stack during at least a part of a buildup of said each stack on each of said'support members from said publication continuous stream andautomatically' during said sensing regulating the speed of movement of said each support member to maintain an upperextremity of said each stack within a predetermined vertical distance range from said stacking region upper end andsaid feeding of said publication continuous stream into saidstacking region.

2. A stacking device as definedin claim 1 in'which said drive means includes at least one variable speed electric drive motor operably connected to said support'members moving said support members in said continuous path at variable speeds dependent on electrical power to'said motor; and in which said stack sensing means includes electric transducer means electrically connected to said drive means motor and positioned relative to said stackingregion upper end for constantly sensing said upper extremity ofsaid each stack during said at least part of said each stack buildup and automatically regulating during said sensing the electrical power to said drive means motor to automatically regulate said speed of movement of said each support member. J

3. A stacking device as defined in claim 1 in which said connected to said sensing arm for regulation by said sensing arm directly dependent on the relative position of said each stack upper extremity within said predetermined vertical distance range, said transducer means being electrically connected to said drive means varying the electrical power to said drive means according to said transducer means regulation to automatically regulate said speed of movement of said each support member during said each stackhuildup.

4. A stacking device as defined in claim 1 in. which said drive means includes variable speed electric drive means operably connected to said support members moving said support members in said continuous path and varying the speed of movement of said support members according to variations in electrical power thereto; 1 and in which said stack sensing means includes electric transducer means positioned relative to said stacking region upper endfmovable dependent on movement of said each stack upper extremity, said transducer means being electrically connected to said electric drive means regulating the electrical power. to said drive means according to said transducer means movement, safety switch means electrically connected to said 'electricdrive means and actionable upon said each stackupper extremity reaching a minimum predetermined vertical distance from said stacking region upper end to direct a predetemiined maximum electrical power to said electric drive means temporarily during said actuation and move said each support member at a predetermined maximum speed.

5. In a stacking device of the type used in a publication convveyor system'and having a main frame mounting a series of spaced stack support members movable in a continuous path downwardly through a stacking region to a stacking region lower end and then upwardly through av return region .disv into said stacks built thereon during said support member movement downwardly through said stacking region and depositing said stacks at said stacking region lower end, the improvements comprising in combination: variable speed drive means operably connected to said support members for moving said support members in said continuous path, said drive means including variable speed electric drive means operably connected to said support members for moving said support members in said continuouspath and varying the speed of movement of said support members according to the amount of electrical power thereto; and stack sensing means operably connected to said drive means and positioned relative to said support member path of movement downwardly through said stacking region for sensing the speed of stack buildup on said downwardly moving support members and automatically controlling the speed ofsaid drive means drive to said support members to maintain during at least a part of said stack buildup an upper extremity" of said stack within a predetermined vertical distance range from said stacking region upper end and said feeling of said publication continuous stream into said stacking region, said, stack sensing means including electric transducer means actionable directly according to the position of said stack upper extremity during said at least part of said stack buildup and electrically connected to said electric drive means for variably regulating electrical power to said electric drive means to automatically control the speed of downward movement of said support member and maintain said stack upper extremity within said predetermined vertical distance range during said at least part of said stack buildup. f

6. A stacking device as defined in claim 5 in which said variable speed electric drive means includes at least one variable speed electric drive motor operably-connected to said support members moving said support members at variable speeds in said continuous path according to the amount of electrical power directed to said drive motor; and in which said stack sensing means includes a sensing arm engaged with said stack upper extremity during said at least part ofsaid stack buildup and movable according to movements in the position of said stack upper extremity, said electric transducer means being operably connected to said sensing arm regulated according to- 7. A stacking device as defined in claim in which said variable speed electric drive means includes at least one variable speed electric drive motor operably connected to said support members moving said support members at variable speeds in said continuous path according to the amount of electrical power directed to said drive motor; and in which said stack sensing means includes a sensing arm engaged with said stack upper extremity during said at least part of said stack buildup and movable according to movements in the position of said stack upper extremity, said electric transducer means being operably connected to said sensing arm regulated according to said sensing arm movements and electrically connected to said drive means drive motor for varying the amount of electrical power to said drive motor accordingto said transducer means regulation, safety switch means electrically connected to said drive means drive motor and positioned engageable by said spaced stack support members separately movable in the same general continuous path downwardly through a stacking region to a stacking region lower end and then upwardly through a return region displaced from said stacking region to a stacking region upper end, infeed conveyor means operably associated with said main frame for feeding a continuous stream of publications to said stacking region upper end and depositing said publications to generally vertical stacks on said support members during said support member movement downwardly through said-stacking region, and guide means operably connecting said support members to said main frame movable in said continuous path and positioned for receiving said publications into said stacks built thereon during said support member movement downwardly through said stacking region and depositing said stacks at said stacking region lower end, the improvements comprising in combination: drive means operably connected to said support members for alternatively progressively moving one of said support members downwardly through said stacking region while the other of said support members remainsfree from movement ready for entrance into said stacking region upper end during at least part of said one support member movement within said stacking region; and stack sensing means operably connected to said drive means and positioned relative to said stacking region upper end for directly sensing an upper extremity of each stack during a buildup of'said each stack on each of said support members from said publication continuous stream and automatically regulating the speed of movement of said each support member during said each stack buildup to maintain an upper extremity of said each stack within a predetermined vertical distance range from said stacking region upper end and said feeding of said publication continuous stream into said stacking region.

9. A stacking device as defined in claim 8 in which said drive means includes variable speed electric drive means operably connected to said support members for providing said support member movement and moving said support members downwardly through said stacking region at variable speedsaccording to the amount of electrical power directed to said drive means; and in which said stack sensing means includes a sensing member positioned for engagement with said each stack upper extremity during said each stack buildup and movable according to said each stack upper extremity, drive speed control means operably connected to said sensing member for regulation according to said sensing member movements and electrically connected to said electric drive means controlling the amount of electrical power to said drive means according to said control means regulation.

10. A stacking device as defined in claim 8 in which said drive means includes at least one variable speed electric drive motor operably connected to said support members moving said support members at variable speeds according to the amount of electrical power directed to said drive motor; and

upper extremity within said predetermined vertical distancerange during said each stack buildup.

11. A stacking device as defined in claim 8 in which said drive means includes variable speed electrically actuated drive means operably connected to said support members moving said support members in said continuous path at a speed according to the amount of electrical power directed to said drive means; and in which said stack sensing means includes movable electric transducer means for constantly sensing said each stack upper extremity during said each stack buildup and regulating the amount of electrical power to said electrical drive means according to the position of said each stack upper extremity relative to said vertical distance range, said trans ducer means increasing electrical power to said drive means during movements of said each stack upper extremity toward an upper limit of said vertical distance range and decreasing electrical power to said drive means during movements of said each stack upper extremity toward a lower limit of said vertical distance range.

12. In a stacking device'of the type used in a publication conveyor system and having a main frame mounting at least two spaced stack support members separately movable in substantially the same continuous path downwardly through a stacking region to a stacking region lower end and then upwardly through a return region displaced from said stacking region to a stacking region upper end, infeed conveyor means operably associated with said main frame for feeding a continuous stream of publications to 'said stacking region upper end and depositing said publications into generally vertical stacks on said support members during said support member movement downwardly through said stacking region, and guide means operably connecting said support members to" said main frame movable in said continuous path and positioned for receiving said publications into said stacks built thereon during said support member movement downwardly through said stacking region and depositing said stacks at said stacking region lower end, the improvements comprising in combination: first drive means operably connected to one of said support members and second drive means operably connected to the other of said support members for alternatively moving said support members downwardly through said stacking region; and stack sensing meansoperably connected to said drive means and positioned relative to said support member path of movement downwardly through said stacking region for sensing the speed of stack buildup during said stack buildup on the particular of said downwardly moving support members then moving through said stacking region and automatically controlling the speed of said drive means drive to said particular of said support'members to maintain during said stack buildup an upper extremity of said stack within a predetermined vertical distance range from said stacking rea f Jim in whichsaid stack-sensing means includes electric transducer means electrically connected to said drive means and movable according to said sensing of said stack buildup speed for regulating' the amount of electrical power to the particular of said tive of said support members for driving said support member at a speed proportionate to the speed of said drive means; and in which said stack sensing means includes electric transducer means electrically connected to saiddrivemeans and movable according to said sensingof said stack buildup speed for regulating the amount of electrical power'to the particular of said drive means to control said particular drive means speed and therebymaintain said stack upper extremity'within said vertical distance range, safety switch meanselectrically connected to said drive means and actionable upon said stack upper extremity reaching a maximum vertical distance within said predeterminedvertical distance range for temporarily overriding said transducer means and directing a predetermined maximum electrical power to said particular of said drive means to move said particular of said support member downwardly at a predetermined maximum speed. a

15. A stacking device as defined in-claim 12 in which each of said first and second drive means includes variable speed electric drive means moving at speeds according to the amount of electrical power directed thereto, said first and second drive means being operably connected to the respective of said support members for drivingsaid support member and regulating electrical power to the particular of said drive means driving said particular of said support member for varying said electrical power to said particular drive means and thereby regulating thedownward speed of said particular support member. 1 I

16. A stacking device as defined in claimf12 in which each of said first and second drive means includes 'a variable speed electric drive motor operably connected tothe appropriate of said support members for alternately moving said support members downwardly through said stacking region, said drive motors moving said support members at speeds proportionate to the amount of electrical power directed to said drive motors; and in which said stack sensing means includes a pivotal sensing arm operably engaged with said stack upper extremity during said stack buildup and movable according to the vertical level of said stack upper extremity; differential electric transformer means having a movable control bar operably connected to said pivotal sensing arm and movable according to movements of said sensing arm, said control bar regulating the amount of electrical power through said differential transformer means by said'control bar movements, said differential transformer means being operably connected to the appropriate of said'drive means atleast during said drive means drive to said particular of said supportmembers for regulating the amount of electrical power to said appropriate drive means to control the speed of said particular of said support member thereby maintaining said stack upper extremity v within said vertical distance range.

17 In a stacking device of the type in a publication conveyor system and having a main frame mounting two sets of spaced stack support members movable in a common continuous path downwardly through a stacking region to a stacking region lower end and then upwardly through a return region displaced from said region to a stacking region upper end, said support members of one set being individually alternately positioned along said continuouspath with the sup port members of the other set, infeed conveyor means operably associated with said main framefor feeding a continuous stream of publications to said. stacking region upper end and depositing said publications into generally vertical stacks on said support members duringsaid support member movement downwardly through said stacking region, and guide means operably connecting said support members to said main frame movable in said common continuous path and positioned for receiving said publications into said stacks built thereon during said support member movement downwardly through said stacking region and, depositing said stacks at said stacking region lower end, the improvements comprising in combination: first drive means operably 'c'onnected to one of member sets for separately driving said other-support member set and the support members thereof, said first and second drive means alternately moving one of said support members of the appropriate of said sets downwardly through said stacking region while the other of said support-member sets remains free from movement with a support member ready for entrance into said stacking region upper end during at least part of said one support member movement within said stacking region; and stack sensing means operably connected to said drive means and positioned relative to said support member path of movement downwardly through said stacking region for sensing the speed of stack buildup during said stack buildup on the particular of said downwardly moving support members then moving through said stacking region and automatically controlling the speed of said drive means drive to said particular of said support member sets to maintain during said stack buildup an upper extremity of said stack within a predetermined vertical distance rangefrorn said stacking region upper end and said feeding of said publication continuous stream into said stacking region.

18. A stacking device as defined in claim l7 in which each of said first and second drive means includes variable speed electric drive means for driving said support member set at varying speeds according to the amount of electrical power directed thereto; and in which said stack sensing means includes variable electric transducer means operably connected movable according to the vertical position of said stack upper extremity during said stack buildup and regulating electrical power to the appropriate of said drive means to control the 19. A stacking device as defined inclaim 17 in which each of said first and second drive means includes variable speed electric drive means for driving said support member set at varying speeds according to the amountof electrical power directed thereto; and in which saidstack sensing means includes variable electric transducer means operably connected tremity within said vertical distance range during said stack buildup, pivotal sensing arm means engaged with said stack upper extremity during said stack buildup and movable with 1 said stack upper extremity, said sensing arm means being operably connected to said transducer means for moving said transducer means, safety switch means'operably connected to said sensing arm means for actuation upon said stack upper extremity reaching a predetermined maximum vertical posi tion within said vertical distance range to electrically bypass said transducer means and direct a predetermined maximum electrical power to said appropriate of said drive means and drive said particular support member downwardly at a predetermined maximum speed.

20. ln a stacking device of the type used in a publication conveyor system and having a main frame mounting a series of spaced stack support members movable in a continuous path downwardly through a stacking region to a stacking region lower end and then upwardly through a return region displaced from said stacking region to a stacking region upper end, infeed conveyor means operably associated with said main frame for feeding a continuous stream of publications to said stacking region upper end and depositing said publications into generally vertical stacks on said support members during said support member movement downwardly through said stacking region, and guide means operably connecting said support members to said main frame movable in said continuous path and positioned for receiving said publications into said stacks built thereon during said support member movement downwardly through said stacking region and depositing said stacks at said stacking region lower end, the

improvements comprising in combination: variable speed drive means operably connected to said support members for moving said support members in said continuous path; and stack sensing means operably connected to said drive means and positioned relative to said support member path of movement downwardly through said stacking region for sensing the speed of stack buildup on said downwardly moving support members and automatically controlling the speed of said drive means drive to said support members to maintain during at least a part of said stack buildup an upper extremity of said stack within a predetermined vertical distance range from said stacking region upper end and said feeding of said publication continuous stream into said stacking region, said stack sensing means being operable independent of speed of said feeding of said publications by said infeed conveyor means other than through said sensing of said stack buildup directly at each one of said downwardly moving support members during said stack buildup.

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