IE41712B1 - Method and apparatus for sorting mail - Google Patents

Abstract

1506516 Sorting postal mail MOUNTAIN STATES TELEPHONE & TELEGRAPH CO 27 Aug 1975 [16 Sept 1974] 35279/75 Heading B8A Mail is sorted by putting it at random in trays 12 and manually (by operators B, Fig. 2) sorting it into labelled trays 14 of a slowly rotating assembly 10. The trays 14 are pulled out and emptied and replaced as they become full and are then replaced. Mail bags 38 may be used instead of certain of the trays 14. The assembly 10 is driven by a motor 22 (Fig. 7) pivotally mounted so that a drive wheel 80 is loaded by gravity against a drive skirt 78 of the assembly. Gravity loading is augmented by a spring 114 adjustable at 136. A manual brake lever 98 presses a brake shoe 102 against a brake ring 96 carried by a skirt 94 of the assembly. An automatic brake (Fig. 5) comprises a wheel 126 frictionally driven by a skirt 82 of the assembly. Slots 124, 128, of the mounting brackets of the axle of the wheel 126, and a spring 132, result in the wheel being biased against the skirt 82 with adjustment provided by a screw 136. A brake disc 162 bearing on the wheel 126 by the action of a spring-loaded plunger 146, is formed with a humped portion 160. The plunger 146 is periodically displaced by the humped portion 160 thus increasing the braking effect. The force of the plunger 146 may be varied by putting in or removing washer-type spacers 156. The effect of the automatic brake is to hold the assembly stationary once it has been stopped; but due to the inertia of the assembly, the brake (if properly adjusted) cannot stop the assembly without additional (e.g. manual) assistance, once it is rotating.

Description

The invention relates to the sorting of mail.

Mail sorting according to destination or addresses is a time-consuming and expensive operation which, up to the present time anyway, is performed manually hy skilled sorters. Theoretically, mail can be coded and machine sorted in the same manner as is commonly done with punch cards and the like; however, no practical way has yet been found to locate the s’ code with the machine and read it accurately, especially when handwritten. Also, no machine capable of accommodating all the various different sizes and shapes of mail automatically, or even partially so,has been developed with the result that operators still manually sort the mail. i According to the present invention, there is provided a method of sorting mail, wherein the mail is sorted at at least one stationary sorting station and is placed manually into removable mail-receiving containers located in compartments which are circulated continuously and repeatedly past the sorting station, each compartment being designated for receiving mail for a particular destination, and the containers with the mail therein are periodically removed manually from the compartments during circulation thereof, and empty containers are placed into those compartments from which the containers with the mail therein have been removed.

Further according to the present invention, there is provided apparatus for sorting mail, comprising an assembly mounted above a base for rotation about a vertical axis, said assembly including a plurality of radially-extending partition walls dividing the exterior thereof into zones, horizontally-disposed shelves bridging the space separating at least some of the adjacent partition walls and subdividing the zones defined therebetween into two or more compartments - 2 41713 arranged one above another in tiered, relation,, and drawerlike mail-receiving bins removably mounted within the compartments, the bins, with the mail therein, being removable from the compartments during rotation of the assembly, and a drive device for rotating the assembly.

Still further according to the present invention, there is provided apparatus for sorting mail, comprising an assembly mounted above a base for rotation about a vertical axis, said assembly including a plurality of radially-extending partition walls dividing the exterior thereof into zones, horizontally-disposed shelves bridging the space separating at least some of the adjacent partition walls and subdividing the zones defining therebetween into two or more compartments arranged one above another in tiered relation, and drawerlike mail-receiving bins removably mounted within the compartments, a friction drive device for rotating the assembly, said drive device comprising a motor carried by one from said base or assembly, and a driven friction wheel in continuous driving engagement with the other from said base or assembly, and a friction brake device for preventing relative movement between the base and the assembly said friction brake device comprising a brake shoe carried by one from said base or assembly and in continuous contact with the other from said base or assembly, said friction brake device being automatically operative to override the fi'iction drive device and to stop the assembly when the speed of the assembly is below a predetermined level, and said friction drive device being automatically operative to override said friction brake device and keep the assembly rotating when the speed thereof exceeds said predetermined level.

As the mail is classified by the sorter according to destination, instead of moving to the appropriate compartment as was previously done, he merely waits for it to come by and tosses the mail into the passing bin as it does so. Contrary to established practice, no sorter need move in front of another or otherwise interfere because each person has independent access to every bin for a brief time interval during each revolution when no one else has access thereto.

The bins and their compartments are preferably colour coded in matching colours which makes it simple to replace the bin in the correct compartment after it has been emptied. These same bin colours constitute destination codes so that the sorter is relieved of the necessity for having to read the address on the bin to distinguish it from other like or similar bins.

Advantageously the bins are stacked one above the other in tiers wherey to increase the capacity of the assembly. It is also possible to leave open spaces between adjacent tiers to accommodate ordinary mail sacks which are detachably retained therein-with quick-disconnect fasteners. .,Such'sacks ate ordinarily used for a rough sort to separate mail going to another location for final sorting such as, for example, a substation, plant, department or other suDd'ivision.

Preferably, the brake device sets automatically whenever the unit is stopped and is effective to hold it stationary under the influence of the starting torque developed by the friction drive all by itself. While the elements of the brake device do not disengage and release - 4 41712 in the sense of the conventional braking system, they can be overridden upon the application of an additional rotational force, the minimum magnitude of which is different depending upon whether such force supplements or counteracts that of the friction drive. Once rotating in the direction driven by the friction drive, however, the inertia of the assembly is such that it will keep on rotating and the brake alone is ineffective to stop it.

The drive device is preferably a modified form of Rockwood drive wherein a condition of imbalance is relied upon to bias a drive element into driving engagement with a driven element while, at the same time, automatically compensating for any wear developing therebetween. The drive device cooperates with the brake device such that the drive device assumes the dominant or controlling position when the assembly is in motion in the driven direction and, conversely, the brake device overrides the drive and maintains the assembly in a stationary condition whenever it is stopped.

The invention will now be described, by way of example only, with reference to the accompanying diai b. . grammatic drawings, .in which: Figure 1 is a perspective’view of mail-sorting and distributing apparatus in accordance with the invention; Figure 2 is a plan view of the apparatus; Figure 5 is a section, to an enlarged scale, taken on line 3-3 of Figure 2; Figure 4 is a fragmentary section taken on line 4—4- of Figure 3; - 5 41712 Figure 5 is a fragmentary perspective view,to an enlarged, scale, showing a braking system of the apparatus; Figure 6 is a fragmentary section showing a brake shoe of the braking system; and.

Figure 7 is a fragmentary perspective view, to an enlarged, scale, showing a friction drive mechanism of the apparatus.

With reference to Figures and. 2 the apparatus comprises a centrally-located, unit/around, which are arranged one or more receiving stations 12 that extend, outwardly · radially therefrom. The receiving stations 12 are angularly-spaced and in the vacant space therebetween, the unloading and distribution function is performed, the latter having been broadly designated by reference numeral 14 and represented by the detached bins 16 and associated radial arrows directed outwardly.

The unit 10 has a stationary floor-mounted base 18 which houses a manually-actuated foot brake 20 and a (Fig. 7) friction drive mechanism 22/ Mounted atop the base for rotational movement relative thereto about a vertical axis is a rotating assembly 24 into which the mail is sorted from the receiving stations 12.

The assembly 24 has a plurality of radially-extending partition walls 26 that diyide the exterior thereof into generally wedge-shaped zones 28. Some,but not all of these zones, include two or more horizontal shelves 30 arranged in vertically-spaced relation one above the other and which function to further subdivide each such zone into several visually-coded pigeonholes or - 6 41712 compartments 32. Removably retained within these pigeonholes 32 are the bins 16 into which the mail from the receiving stations is sorted.

While the entire outside surface of the assembly 24 can be divided into bin-receiving pigeonholes, the particular unit shown has some of the zones 28m left free of shelves 30. Instead of shelves, the opposed partition walls 26 are provided with quick-disconnect clamps 36 of a type effective to releasably fasten an open mail bag 38 therein. A unit having mail bags 36 in addition to the bins 16 is useful where part of the mail sorted is destined for another sorting station or substation to which it is transported directly in the mail bag without having to first sort it into a bin and then empty the bin into a bag.

The receiving stations 12 comprise open-topped elongate trays 40 having pedestals 42 at opposite ends that raise them up to a level about waist high on the operator, or sorter 44. Casters 46 under the pedestals enable the trays to be moved from place to place easily. One caster on each pedestal is preferably of the locking type so that the tray, once positioned relative to the unit 10, $ ' . · f can be locked in place. In Figure 2, four such receiving stations have been shown grouped around the unit 10 in 90° angularly-spaced relation- to one another.

The unsorted incoming mail enters the system at the points identified by arrows A where it is dumped or otherwise deposited into the receiving station trays 40. The sorters 44 stand alongside the trays as represented diagrammatically in broken lines in Figure 2. If one -741712 sorter per tray is used, it seems to make little difference which side of their tray they work from because any two working without a tray between them will be back-to-back making conversation difficult and, alternatively, those who face one another will do so with two trays and about half the unit 10 in between so they can barely see, yet, alone converse. With two sorters at each station, they face one another hut have the sorting tray in between.

The sorters take the incoming unsorted mail dumped into their tray and sort it according to addressee or destination, whereupon, they toss it into the appropriate bin 16 or mail bag 38 corresponding to such destination while the assembly 24 continues to turn, this operation having been represented by arrows labeled B. The assembly 24 rotates at about 12 r.p.m. whereby the sorters can easily read destinations or other information so imprinted upon the front wall 48 of the bins. In addition to the imprinted information on the front of the bins (Figure 1) they are also preferably colour coded to make sure the bin is emptied into p. receptacle headed for the right destination.

A skilled sorter can handle from 35-50 pieces of mail a minute with this sorting system and stand in the same position while doing so. Ko sorter need reach across another because, in time, the bin will move into a position where the mail can be placed therein without interference. Bin labels can be changed at will and more than one bin can be used for mail addressed to the same destination in the case of extra heavy volume. In such a circumstance, the bins are preferably arranged on opposite - § 41713 sides of the assembly. It is even possible to use the same unit for a coarse and fine sort. One sorter, for instance, need only sort hy plant, department or some other major addressee subdivision, whereupon the bins containing the mail thus rough sorted can be returned to the receiving stations and other sorters for a fine sort into some smaller addressee category.

While the sorting operation is taking place, the unit 10 is unloaded and the mail distributed to its destination, In so doing, an operator merely steps into a vacant area between the sorters, pulls a bin from its pigeonhole and empties the contents thereof into an·awaiting receptacle preparatory to returning the empty bin to its original position on a subsequent pass. At most, the sorters only miss one chance at the missing bin because the several seconds it takes to make a complete revolution is ample time to remove a bin, empty it and get ready to replace it. This distribution function has been represented in Figures 1 and 2 by arrows 0 and the detached bins. Also, the mail bags 38 can be pulled, free of their clamps 36 and sent off to their destination while the unit is being used to sort mail. However, the bags are not usually emptied and returned to the unit; ι 1 ; ti instead, the full bag is sent off to its destination and another is clamped in its place while the unit continues to rotate.

Referring to Figures 3 and 4, the central unit 10, comprises an upstanding tubular oenterpost 52 rigidly and non-rotatably mounted within a flanged collar 54 (Figure 3) located at the intersection of crossed beams 56 -s 41712 of a frame 58. Adjustable feet 60 are provided beneath the beams 56 for levelling purposes.

Supported atop frame 58 is an annular skirt 62 overlayed by a horizontally-disposed rim 64 having a large opening 66 in the centre thereof within which is housed a drive flange subassembly 68. Three sleeve bearings 701, 70/n and 704 are journalled for rotation one above the other on the centrepost with the lowermost one 701 resting atop a thrust bearing 72. The lower and middle sleeve bearing 701 and 70«i are interconnected by radiallyextending webs ?Jl- which support a disc 7θ from the underside. This disc is bordered by a marginal drive flange 78 against the inside surface of which a friction wheel 80 of drive mechanism 22 bears at all times to define a driving connection.

On top of this disc spaced concentrically inwardly of the drive flange 78 is an upstanding brake flange 82 which forms part of an automatic brake system 84.

The middle and upper sleeve bearings 70 m and 70t are separated by a sleeve 86. The lowermost shelf 30¾ of the assembly 24 is mounted-atop this upper sleeve bearing for conjoint rotation therewith. Extending upwardly from the shelf 301 are the partition walls 26 that divide the assembly 24 into the- several wedge-shaped compartments 28 and 28'm. The middle and upper shelves 3θ«η and 3O.'u, respectively, further subdivide the zones 28 into the pigeonholes 32 as described above. In the form shown, each pair of adjacent partition walls 26 are bridged by back walls 88 that cooperate with one another to define a central polygonal core enclosing the centrepost, and -id 41712 the back walls 88 in the mail bag zones 28m are preferably moved outwardly to make such zones somewhat . shallower than their counterparts 28 subdivided into pigeonholes.

Bach of the bin-receiving pigeonholes 32 is provided with a stop 90 which limits the penetration of the bin. While the back wall 88 of the pigeonhole would perform the same function, repeated contact of the bin against this wall would, in time, severely dama e same, whereas, the stop 90 can easily absorb such punishment.

Due to rotation of the assembly 24 a centrifugal force component acts to urge the bins out of their pigeonholes. While the speed of rotation is slow enough that the likelihood of this happening is minimal, never15 theless friction lifts 92 are provided on each shelf adjacent the front wall of each bin in supporting relation therebeneath. In order for the bin to be discharged from its pigeonhole by centrifugal force, the frictional component must be overcome and, in addition, the centrifugal force must be of a magnitude sufficient to raise it over the hump produced by the lift. The lifts act to raise the front edge of the bin so that the operator can leave his fingers or thumb underneath it without getting them pinched as he replaces the bin; the lifts also facili25 tate removal of the bins.

Manually-operated foot brake 20 includes an annular skirt 94 suspended beneath the underside of the rotating assembly 24 where it extends down into central opening 66 in the base 18 and is free to rotate therein. Encircling the lower edge of this skirt is a brake band 9S that - 11 41712 faces downwardly. A foot pedal 98 mounted on the base 18 for rockable movement about a horizontal axis intermediate its ends actuates a push rod 100 which carries a brake shoe 102 on top thereof in position to make frictional contact with the brake band 96. The pedal 98 is accessible to the operator within a notch 104 provided for this purpose in skirt 62. Actually, the driving force used to turn the rotating assembly is so small that the unit can easily be stopped by hand and this is often done instead of using the foot brake.

Next, with reference to Figures 3, 4 and 7, it will be seen that the drive mechanism 22 comprises a conventional gear motor 106, the output shaft 108 of which is fitted with the friction drive wheel 80. The motor is mounted for tiltable movement above a horizontal axis defined by pivot pin 110 on a suitably-located element 112 of the frame. This pivotal connection is located well on one side of the balance point of the assembly in the manner of a Rockwood motor mount so that the overbalanced condition continuously biases the friction wheel 80 into driving frictional contact with drive flange 78.

A tension spring 114 connected between the motor and mount therefor supplements the frictional load between the wheel and flange occasioned hy the overbalanced condition alone and it also keeps the motor from bouncing thus maintaining a continuous driving relation between the drive and driven elements.

Finally, reference will be made to Figures 3-6, for a description of the automatic braking system 84.

An upright wall-forming member 116 bridges the space - 11 41712 between sleeve 85 and the brake flange 82 thus providing the means for mounting the braking system 84. A pair of mounting brackets 118 and 120 adjustably mount idler wheel axle 122 in vertical position. The fastener opening 124 on one side of upper bracket 118 is slotted so that it will accommodate a slight tilt in axle 122 to the degree necessary to maintain idler wheel 126 in rolling engagement with brake flange 82. lower bracket 120 is horizontally slotted as indicated at 128 for movement toware and away from flange 82. It is also provided with an ear 150 to which one end of tension spring 152 is attached. The other end of this tension spring is adjustably fastened to bracket 154· carried by skirt 94·.

Brackets 118 and 120 are both loosely fastened to wall 116 so that tension spring 152 can pull the idler wheel into tight rolling contact with flange 82 at all times. Screw eye 156 interposed between the spring and bracket 154 provides the means by which the frictional load therebetween can be adjusted should the occasion for doing so arise. Figure 7 shows a similar screw eye being used on the motor mount tension spring that accomplishes the same purpose. A head 158 atop axle 122 keeps it from falling through the shaft-receiving opening 140 in bracket 118. Thus, idler wheel 126 is'continuously biased into rolling engagement with brake flange 82 at all times.

Permanently fastened to the top of idler wheel 126 is an undulating brake disc 142,the wheel 126 and disc 142 forming a brake shoe. A bracket 144 mounts a brake pin 146 above the brake disc for movement into contact with the marginal edge thereof. This pin is encircled - 13 41712 by a collar 148 that defines a fixed abutment for the lower end of compression spring 150. A threaded pin 152 is fastened in the top of the bracket 144 by two nuts 154 which cooperate therewith and with one another to lock same in axial alignment with pin 146. Spring 150 is retained between these pins and washer-type spacers 156 are used to vary the preload force with which pin 146 engages brake disc 142.

When the assembly 24 is rotating, the driving force exerted by friction wheel 80 against drive flange 78 is adjusted and maintained such that it will keep on turning. This means that the driving connection must exert sufficient force to keep idler wheel 126 turned by brake flange 82 rotating despite the action of pin 146 pressed thereagainst trying to stop it. Saying this another way, the friction drive subassembly 22 must develop sufficient power to keep the rotating subassembly rotating and, in addition, to ride pin 146 up and down, over the undulations in brake disc 142 once the assembly 24 is in motion.

Having once attained this condition through appropriate adjustment of .thb·’Various springs, the assembly 24 should be stopped. The tendency of the drive mechanism 22 is, of course, to start the unit rotating again which it will do unless the force exerted by pin 146 atop brake disc 142 is sufficient to prevent this from happening.

Idler wheel 126 alone is, of course, an inconsequential factor in keeping the assembly 24 from rotating as it is entirely free to roll along the brake flange. Accordingly, to prevent the assembly 24 rotating once it has been stopped, one need only increase the bias on pin 146 until - 154 the drive mechanism is incapable of making such pin climb up over the hump 160 in the brake disc. Thus, once the frictional force developed by the drive mechanism is insufficient to turn the idler wheel through the medium of brake flange 82 until hump 160 is forced past pin 146, the assembly will remain stopped because with the idler wheel unable to turn, it will press against the brake flange with sufficient force to keep the assembly from turning. In the meantime, the drive mechanism continues to run with friction wheel turning and slipping against the drive flange. After stopping the assembly 24, the drive mechanism will actually start to turn it through a fraction of a revolution necessary for the pin 146 to drop into one of the low areas 162 of the undulating surface where it cannot climb out again over hump 160 therein. Once started rotating with sufficient angular velocity to keep the pin 146 riding up over the hump, the friction drive should be adjusted to maintain this condition.

Clearly, this delicate balance must be achieved through trial and error. For instance, just stopping the idler wheel is not enough if spring 132 is not exerting sufficient tension to hold it against the brake flange and keep the drive mechanism from overriding same.

In other words, once the pin keeps the idler wheel from turning, the frictional force between it and the brake flange must exceed that of the friction wheel against the drive flange. Conversely, with the assembly rotating the driving force exerted upon the drive flange must be greater than the retarding force exerted by the pin as it - 15 41712 slides over the undulations in the brake disc.

In the apparatus described the drive flange 78 and brake flange 82 form part of the rotatable assembly It will be apparent that in an alternative arrangement, the flanges 7θ and 82 may form part of the base and the associated friction drive and brake wheels may be carried by the rotatable assembly.

By using the apparatus described, sorting of mail can be considerably speeded.

Claims (14)

1. WHAT WE CLAIM IS:

1. A method of sorting mail, wherein the mail is sorted at at least one stationary sorting station and is placed manually into removable mail-receiving 5 containers located in compartments which are circulated continuously and repeatedly past the sorting station, each compartment being designated for receiving mail for a particular destination and the containers with the mail therein are periodically removed manually from the 10 compartments during circulation thereof, and empty containers are placed into those compartments from which the containers with the mail therein have been removed·

2. A method as claimed in claim 1, wherein two or more stationary sorting stations are grouped around a common 15 set of circulating compartments so that an operator at each station can distribute mail into the said compartments without interfering with the other operators.

3. Apparatus for sorting mail, comprising an assembly mounted above a base for rotation about a vertical axis, 20 said assembly including a plurality of radially-extending partition walls dividing the exterior thereof into zones, horizontally-disposed shelves bridging the space separating at least some of the adjacent partition walls and subdividing the zones defined therebetween into two or more compartments 25 arranged one above another in tiered relation, and drawer-like mail-receiving bins removably mounted within the compartments, - 17 41712 the bins, with the mail therein, being removable from the compartments during rotation of the assembly, and a drive device for rotating the assembly.

4. Apparatus according to claim 3, wherein the drive device is a friction drive and the apparatus further comprises a manually operable friction brake for braking the assembly.

5. * Apparatus for sorting mail, comprising an assembly mounted above a base for rotation about a vertical axis, said assembly including a plurality of radially-extending partition walls dividing the exterior thereof into zoneB, horizontally-disposed shelves bridging the space separating at least some of the adjacent partition walls and sub-dividing the zones defining therebetween into two or more compartments arranged one above another in tiered relation, and drawer-like mail-receiving bins removably mounted within the compartments, a friction drive device for rotating the assembly, said drive device comprising a motor carried by one from said base or assembly, and a driven friction wheel in continuous driving engagement with the other from said base or assembly, and a friction brake device for preventing relative movement between the base and the assembly said friction brake device comprising a brake shoe carried by one from said base or assembly and in continuous contact with the other from said base or assembly, said friction brake device being automatically operative to override the friction drive device and to stop the assembly when the speed of the assembly is below a - ig41712 predetermined level, and said friction drive device being automatically operative to override said friction brake device and keep the assembly rotating when the speed thereof exceeds said predetermined level. 5

6. Apparatus as claimed in claim 5, wherein at least one zone is left sufficiently free of shelves to accommodate a mailbag hung therein, and clips for detachably supporting a mailbag within the zone are mounted upon the opposed surfaces of the partition walls defining the zone. 10

7. Apparatus as claimed in claim 5 claim 6, further comprising means located on each shelf adjacent the front edge thereof to support the front end of a mail-receiving bin resting thereon and tilt the bin rearwardly.

8. Apparatus as claimed in any one of claims 5 bo 7, 15 wherein the drive motor is pivotally mounted on the base for pivotal movement about a substantially horizontal axis, and first spring means continuously biases the friction drive wheel into driving engagement with the assembly.

9. Apparatus as claimed in claim 8, wherein the bias of 2q the spring means is adjustable and the pivotal mounting of the drive motor is positioned to produce an unbalanced condition of the motor whereby the motor pivots in a sense to assist the bias of the spring means.

10. Apparatus as claimed in any one of claims 5 to 9, - 10 41712 wherein the brake shoe comprises an idler wheel in continuous rolling engagement with said other from said base or assembly, and a brake disc with an undulating surface having a hump therein mounted on one side of the idler 5 wheelfor rotation therewith, and a spring-biased pin is carried by the said one from said base or assembly and is positioned to make sliding contact with the undulating surface of the brake disc as the idler wheel rotates, the friction drive device being ineffective to rotate the 10 assembly with sufficient force to move the hump in the surface of the brake disc past the pin when the idler wheel is stationary, and the bias acting on the pin being ineffective to stop the idler wheel from rotating when the assembly is rotating. 15

11. Apparatus as claimed in claim 10, wherein a compression spring biases the pin into continuous engagement with the brake disc, bias adjustment means is associated with the compression spring to vary the biasing force, a spring, which is preferably adjustable, is connected 20 to the idler wheel to normally bias the wheel into rolling engagement with said other from said base or assembly, and the idler wheel is mounted for rotation about an axis tiltable in a plane containing the point of tangency between the wheel and the surface of said other from said 25 base or assembly.

12. Apparatus as claimed in any one of claims 4 to 11, wherein at least two mail-receiving stations are angularly - 2041712 spaced around the assembly, each station comprises an elongate tray-like receptacle extending outwardly radially from the assembly, and a mail collection and distribution station is positioned in the space between adjacent 5 receiving stations, whereby an operator located at the collection and distribution station can remove containers from the respective compartments during rotation of the assembly.

13. A method for sorting mail substantially as 10 hereinbefore described with reference to the accompanying drawings.

14. Apparatus for sorting mail substantially as hereinbefore described with reference to the accompanying drawings.