Improved power stacking apparatus

Abstract: A power stacker (11) for collecting delivered articles such as envelopes from a mailing machine has a support housing (12) having a deck (31) mounted along the housing. A registration wall (145) is fixably mounted to the housing (12) and extending generally perpendicular relative to the deck (31). A stack wall (111) is slidably mounted to the housing (12) at one end of the deck (31) and has a reclined surface (115) extended generally upwardly from the deck (31), the stack wall (111) being slidably mounted to the housing (12) such that the stack wall (111) can be horizontally displaced relative to the deck (31). Support rods (117,119,121,168) are provided for providing article support between the deck (31) and displaced stack wall (111) as well as between the registration (145) and displaced stack wall (111). Threaded hubs (101, 103, 157) are provided for causing the delivered articles to be collected against the stack wall (111) and assume a generally parallel stacked orientation generally parallel to the reclined surface (115). A power stack wheel assembly (200) extends in a cantilevered fashion from the registration wall (145). Stack wheels (222,224) are overrunning on a clutch (220) until power to climb envelope lead edges is needed.

Description: This invention relates to a power stacking apparatus for receiving a stream of articles and causing the articles to be placed in a stack, and, more particularly, to a power stacking apparatus for receiving a seriatim stream of envelopes discharged from a postage meter mailing machine. A power stacking apparatus has been proposed in our European Patent Application (EP-A) 376507. It is particularly suited for receiving envelopes delivered in a seriatim manner from a mailing machine. The power stacker disclosed therein comprises a support housing having a deck fixably mounted along the housing. A registration wall is fixably mounted to the housing and extends generally perpendicular relative to the deck. A stack wall is slidably mounted to the housing at one end of the deck and has a reclined surface extending generally upwardly from the deck. The stack wall is slidably mounted to the housing such that the stack wall can be horizontally displaced relative to the deck. Support rods are provided for providing article support between the deck and displaced stack wall as well as between the registration wall and displaced stack wall. Threaded hubs are provided for causing the delivered articles to be collected against the stack wall and assume a generally parallel stacked orientation generally parallel to the reclined surface. It is the intent of the power stacker disclosed and illustrated herein to receive envelopes from the mailing machine on the stacker deck in a shingled manner. Transport belts with the assistance of a friction stack wheel transport the shingled envelopes to the threaded hubs. The threaded hubs engage the respective envelopes to forcibly cause the envelope to assume a generally vertical biased position against the stack wall. The collection of envelopes against the stack wall causes the stack wall to journey outward in response to forced engagement of the envelopes. It is the further intent of the power stacker to stack mix sized mail of varying thickness of up to 19 mm (three quarters of an inch). It has been empirically determined that the performance of the prior power stacker to consistently stack mixed envelopes of varying thicknesses of up to 19 mm (three quarter of an inch) was unsatisfactory. For example, when stacking three quarter inch thick envelopes, it has been observed that the envelope became lodged at the stack wheel. It is an aim of the present invention to provide a power stacking apparatus having improved stacking capability wherein the power stacking apparatus includes a power stack wheel which improves the consistency of the power stacker to stack envelopes of varying size and thickness. According to the present invention, there is provided a power stacker for collecting delivered articles including a housing having a transport deck, a registration wall mounted to and supported by said deck generally perpendicular to said deck, a stack wall slidably mounted to said housing at one end of said deck and means for transporting articles across said deck in a shingled manner and causing said articles to take up a near-vertical substantially upright edge-supported position biased against said stack wall, characterised by: a power stacker wheel assembly, distinct from the means for transporting articles, having a motor housing, a motor mounted in said motor housing, a stacker wheel rotatably mounted on said motor housing, slip clutch transmission means for providing driving communication from said motor to said stacker wheel to cause rotation thereof, the power stacker wheel assembly being positioned such that an envelope transported on the deck is caused to pass between the stacker wheel and the means for transporting articles; and by the means for transporting articles being a drive means under the control of a motor controller; in which the motor housing is pivotally mounted in a cantilevered fashion to said registration wall; in which the motor has an output shaft mounted in said motor housing; in which the power stacker wheel assembly has a plurality of stacker wheels rotatably mounted to said motor housing; and in which the slip clutch transmission means for providing driving communication from said motor output shaft to said stacker wheels is arranged to cause rotation of said stacker wheels when the rotational speed of the stacker wheels is less than the speed of said drive means. As disclosed herein, the power stacker is comprised of a base section supporting a deck such that the deck is placed at a rearwardly reclining angle of approximately 15° (fifteen degrees). A registration wall is fixably mounted generally vertical along the rear wall of the power stacker such that the registration wall assumes a generally perpendicular orientation with respect to the deck. The deck includes a plurality of parallel aligned endless belts placed around a respective pair of friction rollers for transporting envelopes across the deck. A plurality of threaded hubs (augers) are rotatively mounted to the deck such that each hub extends partially through a recess formed in the deck. A gear assembly is mounted in the housing in driven communication with a motor mounted in the housing for driving the augers. An additional threaded hub or auger is rotatively mounted to the registration wall such that a portion extends through a slot formed in the registration wall and is also in driven communication with the motor through an endless belt. A stack wall is displacably mounted to one end of the housing on slide rods. The stack wall includes a forward reclined surface extending generally vertically from the deck. The power stacker further includes a power stack wheel pivotally mounted to the registration wall to apply downward pressure on the shingled envelopes displaced along the deck as the envelope passes beneath the stack. It has been determined that the stacking is best accomplished by rotating the stack wheel at a linear rate equal to the belt transport rate. The stack wheel is supported by a housing containing a motor which drives the stack wheel through a slip gear arrangement. The motor drives the stack wheel at a speed approximately ten percent slower than the speed of the transport belts. The slip gear arrangement only allows the motor to drive the stack wheel when the speed of the stack wheel has sufficiently dropped below that of the belts which occurs when an envelope has become lodged. The driving action of the stack wheel then causes the envelope to proceed. However, under normal conditions, the stack wheel is allowed to over ride the motor through the slip clutch. The transported envelopes under the influence of the transport belts and the powered stack wheel are then delivered to the stack wall whereupon the threaded hubs engage the envelopes. The hub engagement of the envelopes forcibly causes the respective envelopes to assume a near-vertical (generally vertical) biased position against the stack wall causing the stack wall to move outward in response to forced engagement of the envelopes. Other benefits and advantages of the present invention will be noted or be apparent to one having reasonable skill in the art upon a reading of the following detailed description of the preferred embodiment of the invention, given with reference to the accompanying drawings, in which:- Figure 1 is a partial side view of a power stacker in accordance with the present invention; Figure 2 is a sectioned side view of the power stacker; Figure 3 is a top view of the power stacker; Figure 4 is a sectioned end view of the power stacker; Figure 5 is a schematic of a power stacker motor control in accordance with the present invention; Figures 6A and 6B are side and frontal views respectively, of a power stacker wheel assembly as used in the present invention; and Figure 7 is a schematic top view of the power stack wheel. Referring to Figures 1 to 4, a power stacker, generally indicated at 11, is comprised of a base housing 12 having a base 13. A plurality of vertically extending support posts 15 and 17 (support post 17 being shown in Fig. 3) are fixed to base 13 at one end. The base 13 also has fixed thereto, a forward wall 21 and rear wall 23 in transversely spaced apart parallel and vertical alignment. End walls 25 and 27 are fixed to the base 13 in spaced apart relationship and at their ends to respective walls 21 and 23. A deck 31 is mounted on walls 21, 23, 25 and 27 and along its underside is fixed to the support posts 15 and 17, such that the deck assumes an inclined position, being inclined downwardly front to rear, at approximately 15° (fifteen degrees) to the horizontal. The deck 31 contains a plurality of slots 33, 35 and 37. Fixably mounted to the underside of the deck 31 at the receiving or forward end are first and second adjustable tension brace assemblies 41 and 43. Also fixably mounted to the underside of the deck 31 are braces 45. The braces 45 are longitudinally aligned to a respective brace assembly 41 and 43. Fixably mounted to the underside of deck 31 is a motor mount 48 having a motor 49 mounted thereto. The motor 49 includes an output shaft 51 having a pulley gear 52 fixably mounted around the output shaft 51. A shaft 53 carrying a plurality of fixably mounted friction wheels 55, 57, and 59 therearound is rotatively mounted in the braces 45. The friction wheels are radially aligned to respective first slots 33, 35 and 37. A second shaft 63 is rotatively mounted in brace assemblies 41 and 42. The shaft 63 carries a plurality of friction wheels 65, 67 and 69 radially aligned to the respective second slots 33, 35 and 37. A plurality of endless belts 71, 73 and 74 extend around the respective friction wheel pairs 55-67, 59-65 and 57-69. The shaft 53 further includes a pulley gear 81 which is in endless belt communication with the motor 49 for providing driving force to shaft 53. The shaft 53 further includes bevel gears 85 and 87 fixably mounted therearound in axial spaced apart relationship. The rear wall 23 includes an aperture 89 through which an end portion of the shaft 53 extends and has fixably mounted therealong a pulley 91. End wall 25, Fig. 2, has formed thereon a plurality of studs 91' and 93' through which extends a respective shaft 95 and 97 seated at one end in the end wall 25. Rotatively mounted around the other end of shafts 95 and97 is a respective threaded hub 101 and 103. The threaded hubs 101 and 103 are mounted such that the threaded hubs 101 and 103 partially extend into respective recesses 104 and 106 formed into the deck 31. A bevel gear 92 and 93 is rotatively mounted around the respective shafts 95 and 97 in driving communication with the respective threaded hubs 101 and 103. The bevel gears 92 and 93 are in constant mesh with respective bevel gears 85 and 87. A stack wall 111 has a formed facing surface 113 abutting to the outer face of end wall 25 vertically leading to a vertically reclined surface 115. A plurality of guide rods 117, 119 and 121 are fixably mounted at one end to the facing surface of the stack wall 111. The guide rods 117, 119 and 121 extend slidably through respective apertures in the end wall and are slidably received by respective guide tabs 123, 125 and 127. The guide tabs 123, 125 and 127 are fixably mounted to the underside of the deck. Referring particularly to Figs. 2 and 4, slide rail assemblies 141 and 143 having a rail portion is fixably mounted to the respective side walls 21 and 23. Another rail portion of rail assemblies 141 and 143 are fixably mounted at one end to the facing surface 113 of the stack wall 111 such that the stack wall 111 can be longitudinally displaced relative to end wall 27. Referring more particularly to Figs. 2 and 4, a registration wall 145 is fixably mounted longitudinally along the rear wall 23 and orientated generally perpendicular to the deck. The registration wall 145 includes a recess 147 angled generally perpendicular to the reclined surface 115 of stack wall 111. A brace 149 is fixably mounted to the back surface of the registration wall 145. The brace 149 includes a shaft 151 rotatively mounted therein such that the shaft 151 extends generally perpendicular to the recline surface 115 of the stack wall 111. A pulley 153 is fixably mounted to the end of shaft 151. The pulley 153 is an endless belt 155 in driven communication with the pulley 91 mounted shaft 53. A threaded hub 157 is fixably mounted around the shaft 151. Referring to Figs. 6A, 6B, and 7, the stacker wheel assembly 200 is comprised of a housing 202 having a plurality of motor cooling vents 204. The housing 202 also includes a spacing section 203. Fixably mounted inside the housing 202 by any conventional means, such as, by support tabs 206, is a motor 208. The motor 208 includes a forward bracket 210 and an output shaft 212. The output shaft 212 has fixably mounted therearound a worm gear 214. Rotatably mounted to the bracket 210 by any conventional means is a shaft 216 such that respective end portion of the shaft 216 extends through aligned apertures in the housing 202. Mechanically coupled to the shaft 216 is a one way wrap spring clutch and worm gear combination 220 of any suitable conventional construction, (hereafter collectively referred to as worm gear 220. The worm gear 220 is located along the shaft 216 to be in constant mesh with the worm gear 214. At one end of the shaft 216 outboard of the housing 202 is fixably mounted by any conventional means is a first wheel 222. A second wheel 224 is fixably mounted to the other end of shaft 216 outboard of the housing 202. Each of the wheels 222 and 224, respectively, includes a first canal 226 and a second canal 228 which canals respectively extend endlessly around the respective wheel 222 and 224. A shaft 230 extends through the registration wall 160 and is fixably and detachably mounted at one end to the registration wall 160. The housing 202 is pivotally supported by the shaft 230 in a cantilever fashion such that the wheels 224 ride on deck 31 when no envelope is present. Referring to Figs. 1, 2 and 5, in operation, a suitable motor controller 171 is in electrical communication through line 173 with an envelope feed device 175, for example, a mailing machine, and through line 177 with the motor 49 of the power stacker 12. The motor controller 171 synchronously controls the operating speed of the power stacker 11 and the feed device 175 such that envelopes, for example, 127 mm (5 inch) envelopes delivered by the feed device are received by the power stacker in a shingled fashion with approximately a 19,05 mm (.75 inch) spacing between the leading edges of successive envelopes. The envelopes are transported by the belts 55, 57 and 59, which are under the drive influence of motor 49 through belt 83 and shaft 53, under the stacker wheel assembly 200. The motor controller 171 also causes the motor 208 obtain a speed of approximately ten percent (10%) slower than the drive speed of the endless belts. Thus, the one way (wrap spring) clutch associated with worm gear 220 is in an overrunning mode when no mail is present, or when the bottom endless belts do not slip on the shingled envelopes. When a thick mailpiece (i.e., about 6 mm, 1/4" or greater) is fed into the stacker deck, the tendency is for it to stall upon entering the nip of the stack wheels. Thus, when the mailpiece stalls or slows the speed of the stack wheels below ten percent of the bottom belts, the clutch engages and transmits motion to the mailpiece moving it downstream (the clutch engages to allow the wheels to "climb" the thick mailpieces' lead edge). The leading edge of the lead envelope is then caused to engage the stack wall facing 115 and thereafter assume a generally vertical position against the stack wall. The subsequent envelopes are caused to assume a generally parallel orientation relative to the lead envelope. The positioning of envelopes is assisted by the edge engagement of the envelopes with the threaded hubs 101, 103 and 157. As the envelopes are caused to vertically stack, edge engagement of the envelopes with the threaded hubs 101, 103 and 157 cause the stack wall 111 to be displaced outwardly. The rods 117, 119, 121 and 168 support the stacked envelopes as the stack wall is displaced. Referring particularly to Fig. 6B, it is noted that in the preferred embodiment, each stacker wheel 222 and 224 includes a respective set of canals 226 and 228. Residing in one of the canal 226 or 228 in each stacker wheel 222 and 224 is an O-ring 238. The stacker wheel 222 is located in close proximity to the registration wall 160 and the stacker wheel 224 spaced apart from the stacker wheel 222 so as not to contact the printed indicia on an envelope passing below the stacker wheels 222 and 224. The placement of the O-ring 238 in the respective canals 226 or 228 on the respective stacker wheels 222 and 224 is provided for proper contact with an envelope passing below the stacker wheels. This flexibility is beneficial in that is allows accommodation to the requirement for indicia location as prescribed by various countries. To further illustrate the preferred embodiment of the present invention, a deflector 240 is mounted to the housing 202 by any conventional means in such manner as to permit the deflection between the stack wheels 222 and 224. The preceding particular description is of the preferred embodiment of the present invention and should not be viewed as limiting the invention.

Claims: A power stacker for collecting delivered articles including a housing (12) having a transport deck (31), a registration wall (145) mounted to and supported by said deck generally perpendicular to said deck, a stack wall (11) slidably mounted to said housing at one end of said deck and means (71, 73, 74) for transporting articles across said deck in a shingled manner and causing said articles to take up a near-vertical substantially upright edge-supported position biased against said stack wall, characterised by: a power stacker wheel assembly (200), distinct from the means (71, 73, 74) for transporting articles, having a motor housing (202), a motor (208) mounted in said motor housing, a stacker wheel (222 or 224) rotatably mounted on said motor housing, slip clutch transmission means (220) for providing driving communication from said motor to said stacker wheel to cause rotation thereof, the power stacker wheel assembly being positioned such that an envelope transported on the deck is caused to pass between the stacker wheel and the means for transporting articles; and by the means for transporting articles being a drive means under the control of a motor controller (171); in which the motor housing (202) is pivotally mounted in a cantilevered fashion to said registration wall; in which the motor (208) has an output shaft mounted in said motor housing (202); in which the power stacker wheel assembly has a plurality of stacker wheels (222, 224) rotatably mounted to said motor housing; and in which the slip clutch transmission means (220) for providing driving communication from said motor output shaft to said stacker wheels is arranged to cause rotation of said stacker wheels when the rotational speed of the stacker wheels is less than the speed of said drive means. A power stacker as claimed in claim 1 further comprising said motor (208) being in line communication with said motor controller (171) such that said stacker wheels (222, 224) are caused to rotate at a speed less than the displacement speed of said drive means. A power stacker as claimed in claim 1 or 2 further comprising each of said stacker wheels (222, 224) having a plurality of formed canals (226, 228) therearound and having an O-ring (238) residing in a select one of said canals. A power stacker as claimed in claim 1 further comprising said motor (208) being in line communication with said motor controller (171) such that said stacker wheels (222, 224) are caused to rotate at a speed less than said displacement speed of said drive means when said stacker wheels are stalled by a transported envelope. A power stacker according to any preceding claim, wherein said slip clutch transmission means comprises a one way clutch and worm gear combination operatively connected to said stacker wheel.

Inventors: HOLBROOK RUSSELL W, HOLBROOK, RUSSELL W.
Applicants: PITNEY BOWES INC, PITNEY BOWES INC.
Application year: 1992
Main classification: B65H31
IPC codes: B65H29, B65H31