US3802280A

US3802280A - Box wrapping machine

Info

Publication number: US3802280A
Application number: US00354581A
Authority: US
Inventors: D Shelmire
Original assignee: FMC Corp
Current assignee: Crathern and Smith Inc; New Hampshire Savings Bank
Priority date: 1970-08-10
Filing date: 1973-04-26
Publication date: 1974-04-09
Anticipated expiration: 1991-04-09

Abstract

A box wrapping machine incorporating (1) a low inertia modified planetary drive mechanism for the transfer carriage which moves the incoming box-wrapper units, (2) a control system which senses and monitors the presence and/or movement of the box-wrapper units through the machine, and (3) a conveying mechanism for separating and discharging the finished boxes.

Description

United States Patent 1191 Shelmire 1 Apr. 9, 1974 [54] BOX WRAPPING MACHINE 2,705,905 4/1955 Lange at al. 93/541 2,867,158 1 1959 A d ,J. 1. 9 4. [75] Inventor She'mire Churchvme, 3,236,161 2/1966 A11d12222, J1. :1. 93/541; Pa. 3,264,889 8/1966 Machida et al. 74/89 3,363,474 1/1968 Ritter et al 74/52 [73] Asslgnee' FMC corlmmmnfsan Jose Cahf' 3,401,568 9/1968 Blatt 74 52 [22] Filed: Apr. 26, 1973 3,552,061 4/1969 Hermann 74/89 21 A 1. No.1 354 S81 1 1 pp Primary Examiner-Benjamin W. Wyche Related Application Data Assistant ExaminerWesley S. Ratliff, Jr. [63] Continuation of Ser. No. 62,471, Aug. 10, 1970, Attorney, Agent, or Firm-A. .1. Moore; C. E. Tripp abandoned.

52 US. Cl. 74/89, 93/542 ABSTRACT [5 113'. C1. A box pp g i e incorporating a l iner [58] held of Search 1 74/52: 5 5 tia modified planetary drive mechanism for the trans- 74/89 93/542 30/155 fer carriage which moves the incoming box-wrapper units, (2) a control system which senses and monitors [56] References cued the presence and/or movement of the box-wrapper UNITED STATES PATENTS units through the machine, and (3) a conveying mech- 1,l90,928 7/1916 Markert et al 93/542 anism for separating and discharging the finished 2,924,879 2/1960 Kraus, Jr 30/155 boxes.

585,416 6/1897 Wattles 1 74/219 691,329 1/1902 Smith 93/542 7 Claims, 25 Drawing Figures PATENTEDAPR 91914' 3,802,280

' sum 010F12 BOX STAYING MACHINE GLUING MACHINE 0 BOX REGISTERING MECHANISM D BOX WRAPPING MACHINE K ,o

' INVENTOR. |2 I 4 o5 DONALD w. SHELMIRE BY 141W ATTORNEYS PATENTEBAPR .9 um

um our 12 PATENTED APR 9 I974 SHEET 0a or 12 PATENTEDAPR 91914 3,802,280

- sum 10m 12' BOX WRAPPING MACHINE This is a continuing application of my copending application, Ser. No. 062,471, filed on Aug. 10, 1970, now abandoned; both applications disclose and claim common subject matter.

BACKGROUND OF THE INVENTION -The field of the present invention concerns those types of wrapping machines wherein an outside wrapper is folded around a box, a box cover or around a similar container.

One prior art wrapping machine of the type above referred to evolved from the wrapping machine disclosed in the U.S. Patent of Smith, No. 691,329 and today retains the same general form, structure and mode of operation. Later issued patents concerning the same basic machine are Lange, No. 2,705,905, and Andresen Jr. et al., No. 3,236,161. In general terms, the mode of operation of a typical manual box wrapping system and of the box wrapping machine incorporated therein is as follows: A gluing machine applies adhesive toa wrapper, and deposits the wrapper adhesive side up on a main conveyor belt. Alongside the conveying belt is a box staying machine which erects box blanks and places the boxes open end up on'abox conveyor that delivers the set-up boxes on an unwrapped-box supply table. The boxes on the supply table are located across the main conveyor belt from an operator who manually places a box open end up upon the adhesive face of a wrapper on the main conveyor.

Near the end of the main conveyor the box-wrapper units are sequentially arrested in alignment with the box wrapping machine which is provided with a transfer carriage that moves across the belt to pick up a boxwrapper unit and deliver it to the box wrapping machine. ln a similar system, disclosed in Andresen Jr. et al., No. 2,867,158, the box and wrappers are automatically registered and no manual operations are necessary. The latter system includes a box staying machine which delivers finished boxes to a gluing machine. The gluing machine applies adhesive to wrappers and places the wrappers adhesive side up on a conveyor belt. A registration mechanism operates in conjunction with the gluing machine and overlies the conveyor belt. Each wrapper and a box are brought into exact alignment by the registration mechanism, following which the box-wrapper units are delivered in the previously described manner to the box wrapping machine. This automatic system is faster than the manual system.

Moved into the box wrapping machine, the boxwrapper unit is located ata folding or forming station where a vertically reciprocating forming block and other mechanism fold the wrapper upward against the sidewalls of the box, inward over the upper edges of the box, and downward against the inner surfaces of the sidewalls. The wrapped boxes are ejected in the same direction in which they entered the machine, onto a discharge table for further handling operations.

Several interrelated problems arise when an ordinary box wrapping machine is speeded up to take full advantage of the production rates possible in an automatic box wrapping system. One problem is that of sensing and controlling the various mechanical manipulations of the box-wrapper unit so that malfunctions can be rapidly detected and the transfer carriage of the box wrapping machine stopped by the control and sensing system before the machine jams or is damaged. This is difficult to accomplish in some of the patentedmachines because the transfer carriage is reciprocated by a driven flywheel eccentrically coupled to the carriage, and the inertia of the flywheel system strongly resists any applied stopping force. A further difficulty when the output is increased arises from the fact that the adhesive has less time to set. Thus, impact and relative motion between adjacent boxes butted together causes wrinkling and distortion of the wrapper and transfers glue from box to box. These three problems (1) the sensing and control (2) the reducing of the transfer carriage inertia and (3) the separation of the wrapped boxes until their adhesive is set are all met with the objective and attainment of more rapid production speeds than have previously been reached.

1n the Lange et al. Patent, No. 2,705,905, the transfer carriage drive mechanism includes a crank arm requiring a somewhat complex Geneva escapement, plus the further disadvantage of a relatively large area for rotation of the crank arm and for oscillation of the link connecting the crank arm to the transfer carriage. This drive arrangement develops and subjects the transfer carriage to other than the desired linear reciprocating motions, thus subjecting both the transfer carriage and the drive system to undue wear, and causing noisy operation if all of the operating clearances are not properly maintained. If the Lange et al drive mechanism is operated at higher than usual speeds the foregoing operating disadvantages are aggravated, and the shock loads on the Geneva mechanism become inordinately high, as does the rotation inertia of the inherently unbalanced drive mechanism. Even more consequential is the fact that the Lange et al. drive mechanism cannot be utilized in the present box wrapping system wherein the discharge path of the boxes is along the longitudinal centerline of the transfer carriage.

Another prior art patent which is pertinent to the herein disclosed and claimed transfer carriage drive mechanism is the U.S. Patent of Ritter et al., No. 3,363,474 issued Jan. 16, 1966, with an Austrian priority date of July 8, 1964. The ritter et al. patent is di- 'rected to a mechanism for assembling wire mesh screen, and for that purpose incorporates a .lever system having two equal length pivotally interconnected levers movable in a vertical plane wherein the angular movement of one lever about its pivotal mounting point swings the other lever twice that angular distance in the opposite direction about the pivotal interconnection. This type of mechanism produces linear motion for the end of the free lever, and in the Rltter et al. patent is employed in a feed mechanism in which the anchored lever oscillates about 72 to advance a wire, gripped to the end of the free lever, along a linear path. The present invention advantageously employs a similar linear drive principle by moving the levers in a horizontal plane and oscillating the anchored lever in an arc of thereby causing a linearly movable transfer carriage attached to the end of the free lever to travel a path as long as the length of the combined levers. The advantages which result from the present construction include an unobstructed discharge end for the transfer carriage, since the boxes are discharged along the centerline of the transfer carriage.

,A publication which is pertinent to the present invention is an article published in June, 1964, in MACHIN- ERY magazine, believed to be a domestic publication.

The article is titled Mechanism Which Increases Movement By Levers and Chain, on page 158. In order to increase the stroke of a slide mechanism beyond that which could be conveniently obtained by a direct drive link, the link is utilized to swing a lever system, in a vertical plane, which amplifies the link motion. For this purpose, the drive link is pivoted on the axis of a fixed sprocket to the central portion of a pivotally anchored lever. The free end of the lever carries a rotatable shaft and sprocket secured to a second lever. A chain trained around the two sprockets causes the second lever to rotate relative to the first lever, such that the second lever inverts between the approximately 45 limits of the stroke of the first lever, and causes a slide pivoted to the free end of the second lever to travel a distance exceeding the stroke of the drive link.

SUMMARY OF THE INVENTION chine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan of a typical box wrapping system incorporating the box wrapping machine of the present invention.

FIGS. 2-11 are diagrammatic perspectives illustrating the sequential operations performed upon a box and wrapper in a box wrapping machine.

FIG. 12 is an enlarged elevation viewed in the direction'of the arrows 12-12 on FIG. 1.

FIG. 13 is a sectional plan view taken along the plane 13-13 on FIG. 12 at a slightly enlarged scale.

FIG. 14 is a fragmentary isometric of the transfer carriage, discharge conveyor, and the transfer carriage drive means of the present invention.

FIG. 15 is an enlarged isometric of the FIG. 14 discharge conveyor.

FIG. 16 is an enlarged vertical section taken along lines 16-16 on FIG. 13.

FIG. 16A is. an enlarged fragmentary elevation taken in the direction of the arrow 16A on FIG. 16.

FIG. 17 is a section taken along lines 17-17 on FIG. 16.

FIG. 18 is an enlarged plan of the drive mechanism indicated by the arrow 18 on FIG. 13.

FIG. 19 is an elevatiom partly in section, taken in the direction of the arrows 19-19 on FIG. 18.

FIG. 20 is a section taken along lines 20-20 on FIG.

19.. FIGS. 21-23 are diagrammatic views, similar to FIG. 18, showing sequential operational positions of the transfer carriage drive unit.

FIG. 24 is a schematic diagram of the electrical control system of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT A typical automatic box wrapping system 28 (FIG. 1) is, as disclosed in Pat. No. 2,867,158, provided at its upstream end with a box staying machine A which forms and ejects upwardly open boxes B onto a box conveyor BC. The boxes are fed into a gluing machine C which applies a partial or overall coating of adhesive to a wrapper W and feeds it, adhesive side up, under a box registering mechanism D. A plunger of the box registering mechanism centers a box over a wrapper and brings the box and wrapper into adhesive contact. The box and wrapper units BW are conveyed away from the registering mechanism on a vacuum belt conveyor E.

The vacuum belt conveyor E operates intermittently, and each box-wrapper unit BW (FIGS. 1 and 2) ultimately comesto rest against a transverse stop mechanism G at a pickup station H. While thus stopped, a reciprocable transfer carriage I (FIGS. 1 and 3) of a box wrapping machine K advances across the conveyor E, grips the box unit BW and retracts to deposit the box unit at a forming station L (FIGS. 1 and 4) on a resiliently biased lower form block LF (shown in FIG. 5). With one down and up movement of an overhead plunger mechanism M, which carries an upper form block HF and a middle form block MP, the plunger M pushes the box unit BW and the lower form block LF downward, and the box unit is carried past forming tools adjacent thevertical walls of the box. The outwardly extending flaps of the wrapper W (FIGS. 1 and 5-11) are folded upward against the side walls of the box B, inward over the upper edges of the walls, and downward against the inner surfaces of the walls.

Meanwhile, the transfer carriage Ihas picked up the second box unit BW. When the second box unit is transferred to the forming station under the plunger M, the wrapped box is moved by the carriage away from the forming station into gripped relation with a discharge conveyor N. The conveyor moves the wrapped box away from the forming station so that when the second box is finished and transferred to the discharge conveyor, the two boxes are spaced apart. Thus, even if there happens to be any unset adhesive exposed on either box, the boxes only contact each other after they have been ejected onto a receiving table 0, at which time the adhesive has set sufficiently to hold the wrapper firmly in place and prevent distorted wrappers or gluing the boxes together.

With more specific reference to FIGS. 2-11, the stop mechanism G is conventional and includes a stop bar 30 that is adjustably positioned along the conveying flight 32 of the vacuum conveyor E to immobilize the box unit BW in centered relation with the path of the box unit toward and through the box wrapping machine K. Two inwardly directed rods 34 of the stop mechanism G have inner ends which are spaced from the box unit at initial delivery, and which allow slight movement of the box unit away from the transfer carriage during the initial part of the transfer operation so that the box closes a normally open microswitch SW1 mounted on one of the rods to initiate the operation of a later described control circuit which is part of the present invention. r

The transfer carriage I (FIG. 3) is similar to that disclosed in Lange et al., supra, and is provided'with reciprocable side members 36, each of which includes a shaft 38 that is slidably mounted in a bearing block 40 (FIG. 4). Pedestals 42 (FIG. 12) support the bearing blocks 40 from a slide frame 44, on a main frame 43, and an opposed slide frame 46. Each slide frame carries various flap manipulating tools at 48 for folding the wrapper W about the box B, and the slide frames are adjustable toward and away from the vertical path of the box for handling different sizes of boxes. In similar manner, a slide frame 50 and an opposed slide frame, not shown, carry similar flap manipulating tools and are also adjustable toward and away from the vertical path of the box.

With brief reference to FIG. 14, the transfer carriage side members 36 are each clamped in a block 52 which is in turn clamped to a drive link 54. A later described drive mechanism 56, a novel and important part of the present invention, is coupled to the center portion of the drive link 54 to reciprocate the transfer carriage. At the opposite end of the transfer carriage spring biased pivotally mounted gripping fingers 58 are cammed inward by the box B as the carriage moves toward its FIG. 3 position, and then pivot toward each other to engage the rear corners of the box. As previously mentioned, the switch SW1 is closed during this box gripping operation.

Forward of each gripping finger 58 is an adjustable stop 60 which engages the front wall of the box, and an ejecting finger 62. When the transfer carriage I moves a second box from the pick-up station H (FIG. 2) to the forming station L (FIG. 4), a previously transferred box unit BW which by this time has been completed is picked up by ejecting fingers 62 and moved downstream for discharge by the discharge conveyor N.

As the box unit BW is transferred from the FIG. 3 position to the FIG. 4 position, it blocks the light beam of a photoelectric unit comprising a light projector 64 and a sensor 66 which are associated with the later described control circuit of the present invention. To support the leading flap of the wrapper so that it does not bend downward during transfer of the box unit, vacuum nozzles 70 which are fixed to the transfer carriage engage the corner portions of the leading flap of the wrapper. The nozzles in downstream positions individually overlie support rails 71 (FIG. 14) which support the box unit after they are unsupported by the lower form block LF during discharge from the wrapping machine. At the forming station L (FIG. 4) the box unit BW is supported upon the lower form block LF (FIG.

5) and in vertical alignment with the overhead and descending form blocks UF and MF.

The upper form block UF is mounted on a vertically reciprocable plunger shaft 72, and the middle form block MF is mounted on two vertically reciprocable plunger rods 74. Both form blocks move together downward into the box B and push the upwardly biased lower form block LF and the box unit BW past flap manipulating tools 48 (FIG. 5) on the slide 50 (FIG. 12) and on the opposed slide, not shown. As shown in FIG. 5, the manipulating tools at a first level fold the leading and trailing flaps of the wrapper W upward against the walls of the box B.

At a second, lower level (FIG. 6) other of the flap manipulating tools 48 are actuated to fold the end portions of the upwardly folded flaps around the adjacent corners of the box and against its lateral end walls while the form blocks UP and MF are-within the box. Progressing downward, the box unit BW (FIG. 7) is moved past further flap manipulating tools 48 which fold the lateral end flaps upward onto the adjacent and walls. At this position, downward. movement of the box unit stops, and during a dwell period the upper form block UF is elevated (FIG. 8) and the flap manipulating tools 48 move inward from each side of the box unit and fold the upstanding free edges of the wrapper into underlying relation with the upper form block while the box unit remains clamped between the middle and lower form blocks MF and LF.

In order to complete the folding of the wrapper W (FIG. 9) the upper form block UF is moved downward into the box unit BW as the flap manipulating tools 48 are retracted. The entire assembly returns to the initial starting level where the form blocks are next removed from the completed box. For this purpose, four stripper rods 76 are moved downward through apertures in the form blocks and hold the bottom wall of the box against the lower form block LF while the upper and middle form blocks UP and MF are retracted clear of the completed box unit BW. Meanwhile, the transfer carriage I has gripped the next unfolded box unit BWZ and the ejecting fingers 62 are in a position upstream of the completed box unit.

After the stripper rods 76 are elevated clear of the box as shown in FIG. 11, the transfer carriage I makes its second movement toward the forming station L, to feed the second incoming box unit BW2. The ejecting fingers 62 thus start to eject the finished box, whereupon the box moves into gripped engagement with the discharge conveyor N and out of the box wrapping machine K. In contrast with similar box wrapping machines in which the finished boxes push one another out of the machine, whereupon anyexposed adhesive will glue the finished boxes together, the discharge conveyor N isolates each box until it is discharged from the wrapping machine to prevent wrinkling of the wrapper and transferring glue from one box to another.

The structure to which the present invention is directed, the drive for-the transfer carriage I, the discharge conveyor N, and the electrical monitoring control system which cooperates with the conveyor and carriage, cooperatively result in increasing the output of the box wrapping machine K to an extent far beyond the possible output of a manual type of box wrapping system. The following description is directed primarily to these machine elements and the electrical control system. Other portions of the box wrapping machine K are described only to the extent necessary to disclose the present invention, with appropriate reference made, where necessary, to patentswhich disclose comparable structure in greater detail.

Referring to FIG. 12, power for the box wrapping machine K is supplied by a motor 80 mounted on the frame 43 of the wrapping machine. A drive arrangement, not shown, synchronizes the operation of the wrapping machine with the gluing machine A and the vacuum conveyor E. Conveyor E is driven intermittently by the gluing machine. A variable speed belt transmission 82 powers an electrically disengaged clutch 84 for selectively coupling driving power to an input shaft '86. The clutch 84 is unitary with an associated brake which is engaged when the clutch is disengaged. The other end of the input shaft 86 (FIG. 16) extends through a housing 88 that contains a speed.- reducing gear connection to a vertical cam shaft-90 which drives a barrel cam 92. During each cycle of the box wrapping machine K, the cam 92 makes one complete revolution and the form blocks Ill" and MI are moved from their FIG. 4 position through the positions illustrated in FIGS. -11 (the FIG. ll position being the same as FIG. 4 position).

For the latter purpose, a cam lever 94 (FIG. 12) is pivoted at 96 to a fixed frame member and is provided with a cam follower roller, not shown, which is engaged with a recessed cam track 98 of the barrel cam 92. By means of a connecting rod 100, the cam lever 94 operates an overhead main plunger lever 102 that is pivoted at 104 to a pedestal 106. A link 108 on the main plunger lever is connected to the plunger shaft 72 which actuates the middle form block MF and also controls the upper form block UF. In similar manner, another cam lever, not shown, has a cam follower engaged with a cam track 110 to actuate, by means of a connecting rod 111 (FIG. 13), an auxiliary plunger lever 112 (FIG. 1) that is connected to a vertically movable stripper yoke 114 that carries the depending stripper rods 76.

With more specific reference to FIGS. 13-16, the discharge conveyor N and the transfer carriage I, two T- shaped pedestals 116 interconnected by lateral tie bars 118 and 119 support these structures from the machine frame 43. The drive link 54 (FIGS. 13 and 16) is provided at each end with an arm carrying follower rollers 120 and 122 (see FIG. 13), respectively rotatable about vertical and horizontal axes, which are guided by elongate fabricated tracks 124 that are secured tothe adjacent pedestal 116. As previously mentioned, the pedestals 42 which support the upstream end of the transfer carriage l are mounted on the adjustable slide members 44 and 46 (FIG. 12). Thus, it is only necessary to loosen the mounting blocks 52 (FIG. 14) to simultaneously adjust the slide members and the

carriage elements

36, 38 and 40 of the transfer carriage for accommodating a different size box. The discharge conveyor N is similarly adjustable, as next described.

Mounting means for the discharge conveyor N (FIG. 14) includes two generally L-shaped mounting

plates

128 and 130, best shown in phantom lines in FIG. 15. One convenient manner of adjustably mounting the

plates

128 and 130 is to provide a depending flange, as at 132 for the mounting plate 128, which has bolts extending through a slot 134 in the tiebar 1 19. The other end portions of the mounting plates may be similarly mounted in slotted portions of the tie bar 118. The drive means for the discharge'conveyor N includes a gear 136' (FIGS. 13 and 16) which is mounted on the cam driveshaft and is meshed with a'smaller gear 138 on a shaft 140. Shaft 140 extends through a bearing bracket 142 atop a part of the frame 43, and is coupled to a chainand sprocket drive train 144.

7 As clearly shown in FIG. 14, the drive train 144 powers a shaft 146 which is held by a bracket 148 on the adjacent pedestal 116. A similar shaft and bracket 150 and 152 (FlG.l6) is mounted on the other pedestal 116. The

shafts

146 and 150 carry aligned belt pulleys 154 and 156 that support a drive belt 158. As best shown in FIG. 15, the drive belt 158is trained around an idler pulley 160 and a driven pulley 162 that are supported by the mounting plate 128. Pulley 162 is secured to a shaft 164 that extends upward through the mounting plate 128 and carries a pulley 166 which is aligned with three idler pulleys 168 and a tensioning pulley 170. A belt 172 trained around the pulleys 166,

168 and forms one half of the discharge conveyor N. The other half of the discharge conveyor includes a belt 174 which requires a reverse drive arrangement so of the same size and in mesh with the gear 178 is secured to a shaft 182 that drives a pulley 184 for the belt 174. Three idler pulleys 186 and a tensioning pulley 188 complete the support means for the belt 174. It will be noted that coextensive and simultaneous lat-' eral adjustment of the mounting

plates

128 and 130 does not affect the tension of the drive belt 158.

Before next proceeding to the drive arrangement for reciprocating the transfer carriage I, it should be noted that finished box units conveyed along the support rails 71 (FIG. 14) interruptthe light beam, from a projector 190, that otherwise impinges a photoelectric sensor 192. The function of these elements are later described in conjunction with the FIG. 24 control circuit.

The driven end of the cam driveshaft 90 (FIGS. 16 and 17) is located in a housing 194 having an upstanding boss 196 offset-from the driveshaft 90 and mounting a pivot shaft 198. An elongate lever 200 is pivoted on the shaft 198 and carries a gear segment 202 on its free end. Intermediate its ends, a lateral arm 203 on the lever 200 is provided with an upstanding cam follower roller 204 which is engaged with a cam track recess 206 on the lower end of the cam '92. The cam track oscillates' the gearsegment 202 between the full line and phantom line positions of the lever 200, as shown in FIG. 17. Since the cam 92 rotates counterclockwise as viewed in FIG. 17 and the section 206 of the cam track which is next engaged by the follower roller 204 is nearly concentric with the shaft 90, the transfer carriage drive link 54 will dwell at the positionillustrated. This dwelling position corresponds to that in which a box unit .BW is aligned with the forming blocks to allow time for the wrapper to be folded around the box.

Gear segment 202 is meshed with a gear 208 and the drive ratio is such that the gear 208 oscillates through an angle of 180. A box 210 (FIG. 16) in the housing 194 supports the lower end of a shaft 212 which is located on the longitudinal centerline of the transfer carriage -l and is driven by the gear 208. The upper end portion of shaft 212 extends through a support neck 214 that is fixed to the frame 43, and provides the power for the drive mechanism 56 which reciprocates the transfer carriage'l. v I Y With reference to FIGS. 18 and 19, the upper face of the support neck 214 is counterbored to mount the hub 216 of a double sprocket 218 that is locked against rotation by a bolt 220. A bearing 222 for the shaft 212 is recessed in the upper face of the sprocket 218, and one lever 224 of a two piece articulated sweep or drive arm 226 is clamped and keyed on the shaft 212. One extreme of movement for the sweep arm lever 224 is shown in FIG. 18, the other extreme being diametrically opposite since the shaft 212 reciprocates through an angular extent of 180.

It should be noted that the sweep arm lever 224 is of open cast construction with ribs and flanges to make it as light as possible in order to reduce, as far as is practical, the oscillating mass which includes the sweep arm lever 224. The other lever 228 of the articulated sweep arm 226 comprises a similar lightweight casting which is clamped and keyed to a shaft 230 that is rotatably carried by the free end of the arm 224. A double sprocket 232 with half the number of teeth of the sprocket 218 is secured to the lower portion of the shaft 230 and chains 233 are trained around the sprockets. A double idler sprocket 234 for tensioning the chains is carried by a swinging link 236 (FIG. that depends from a laterally offset bracket 238 of the arm 224.

The free end of the outer lever 228 of the articulated sweep arm 226 carries a pivot bolt 240 that couples the lever to a drive link 242. Link 242, in turn, is coupled to a pin 244on the drive hnk 54 of the transfer carriage I. As the shaft 212 oscillates as illustrated in FIGS. 21-23, the pivot bolt 240 is moved in a linear path coincident with the longitudinal cent e rlirie CL 7 of the transfer carriage I. Thus,- sincethe driverat io of sprockets 218 and 232is 2:1, the distance between the axis of the pivot bolt 240 and the axis of the shaft 230 is exactly equal to the distance between the axes of the

shafts

230 and 212. Because normal manufacturing tolerances and chain backlash may cause the pivot bolt 240 to deviate very slightly from a linear path, it is preferable to use the drive link 242 to prevent binding which might otherwise occur if the pivot bolt 240 connected directly to the transfer carriage drive link 54.

FIGS. 21-23 illustrate the operation of the transfer carriage drive mechanism 56, and clearly indicate the unique advantages thereof in its present application, namely (1) relatively low reciprocating mass, (2) substantially no lateral forces on the transfer carriage and (3) long operating driving strokes in a relatively compact drive mechanism.

In the present case the transfer carriage drive link 54 (FIG. 21) has a 16 inch stroke to its other extreme of movement shown in FIG. 23. Thus, the

sweep arm levers

224 and 228 are each only 4 inches long between their connecting axes, but the radial extent of the drive mechanism parts is only slightly more than half the length of the operating strokes because of the articulated or folding sweep arm 226. In conjunction with the lower operating mass, the end result is that the transfer carriage I can be quickly started and stopped, an important feature in providing effective control of the box wrapping machine without adversely affecting its high output of finished, wrapped boxes.

As the lever 224 (FIG. 21) moves.45 degrees counterclockwise to the position shown in FIG. 22, the lever 228 is swung 45 clockwise due to the described 2:1

drive chain and sprocket arrangement. Therefore, the pivot bolt 240 and pivot pin 244 move linearly along the centerline CL. This same linear driving force exists as the levers move through the FIG. 22 phantom line positions to the FIG. 23 positions; the driving force applied to the transfer carriage I has no lateral components. It will be apparent, therefore, that the transfer carriage can be lightly constructed to facilitate rapid driving movement of the box units BW being moved through the machine. This is in marked contrast to previous drive systems using an eccentric drive link and flywheel arrangement. Those systems are characterized by having high inertia that impairs effective control of the transfer carriage in a rapid production cycle.

It becomes critical, with the rapid operating speeds attained, to continuously monitor the operations to avoid jams due to improperly shaped boxes fed into the box wrapping machine, or due to possibleother malfunctions that might interrupt the normal movement or wrapping of a box unit. These general functions are carried out by the control circuit of FIG. 24, which includes five cam-operated switches SW2, SW3, SW4, SW5 and SW6 shownin FIG. 16A. Each switch is operated by an individual cam 248 that is mounted on an upper extension of the cam driveshaft 90, and this rotates once per box-wrapping cycle.

Referring to FIGS. 2 and 13, the incoming box unit BW is arrested by the stop bar 30 and is adjacent the actuator of the switch SW 1. When the transfer carriage I is moved to position the gripping fingers 58 (FIG. 3) beyond the rear corners of the box unit, the box unit is pushed against the switch actuator and the switch contacts close to momentarily energize the control system. Switch SW1 (FIG. 24) is in series with a control relay CR1 in a line 250 extending across power input lines L1 and L2. Control relay CR1 is thus energized, and its holding contacts CR-l in a line 252 close. At this time the cam operated switch SW2 in a line 252 is closed, and the control relay CR1 remains energized as the transfer carriage gripping fingers 58 pull the box unit toward the box wrapping machine. An electrical condition has thus been initiated which indicates that a box unit was present and gripped at the pickup station H (FIG. 1).

. As the box unit BW (FIG. 3) is moved by the transfer carriage between the photoelectric sensor elements 64 and 66 (the former being energized by a transfonner T1, line 249) the cam operated switch SW3 in a line 254 is closed. A control relay CR2 is'in series with switch SW3 and thephotoelectric sensor 66, and is thus energized when a box unit interrupts the light beam from the projector 64. Immediately after the box unit passes through the light beam, one set of contacts of the cam operated switch SW4 in a line 256 are closed. In the event that the relay CR1 closed, but control relay CR2 did not close due to a malfunction which prevented transfer of the box unit across the photoelectric sensor 66, the electrically operated clutch and brake unit 84 (FIG. 12) is actuated to disengage driving power to the box wrapping machine and set the brakes.

If no box transfer occurs after the control relay CR1 is actuated, a delay timer DT, line 256, is energized through the closed contacts of switch SW4, normally closed contacts. CR2-2, line 255, of the control relay CR2, and the switched contacts CR1-2 of the control relay CR1. Contacts DT-l of the timer DT close and energize a clutch solenoid S, line 258. Thus energized,

gized, thus opening the contacts CR2-2, line 255, and.

opening contacts CR1-3, line 256 so that the delay timer DT is electrically isolated and the transfer of the box unit is completed to the forming station L (FIG. 4).

A control relay CR3, line 253, is connected to another set of contacts of the cam operated switch SW4. An electrical path is thereby completed through control relay contacts CR2-1, line 253, and the cam operated switch SW2 to energize the control relay CR3 while the wrapper W is being folded around the box B. Normally open control relay holding contacts CR3-1, line 260, close, and in conjunction with the now closed cam operated switch SW6, the control relay CR3 remains energized. It will be seen that the control relay CR3 is only energized if the control relays CR1 and CR2 signalled that a box unit was transferred (no malfunction). Following the operation of the control relay CR3 as described, the cam operated switch SW2, line 252, opens, and the control relays CR1 and CR2 are deenergized. This conditions the control system for the above described operations to repeat with the next incoming box unit.

At this point the box unit at the forming station I has been wrapped and ejected into gripped relation with the belts of discharge conveyor N (FIG. 11). At a given point in the overall cycle, the finished box passes under the light beam projector 190 (FIGS. 13 and 14) and blocks the beam from the photoelectric sensor 192 (FIG. 24, line 262). The sensor is operative, when its light beam is interrupted, to energize a control relay CR4 and its normally open holding contacts CR4-1, line 26], close. In conjunction with the closed cam operated switch SW6, the control relay CR4 remains energized after the finished box clearsthe photoelectric sensor 192 and is discharged onto the table (FIG. I The finished boxhas now generated a control signal that it has cleared the box wrapping machine. Next, the cam operated switch SW5, line 264, closes. If there is no such control signal generated, some malfunction exists between the forming station L and the receiving table 0, and the brake solenoid S is again energized to disengage the clutch, set the brake, and stop the box wrapping machine. This action is initiated by the cam operated switch SW5. Upon closing, the contacts of switch SW energize the delay timer DT by means of normally closed control relay contacts CR4-2, line 263, and the switched contacts CR3-2 of the control relay CR3, whereupon the delay time contacts DT-l energize the solenoid S to actuate the clutch and brake 84' (FIG. 12). If the photoelectric sensor 192 is actuated by a box interrupting its light beam, the control relay CR4 is energized as previously described, and the sole noids are electrically isolated by the normally closed but now open contacts CR3-3, line 264,-and CR4-2,

line 263. g

It will be apparent that the FIG. 24 control system monitors a series of events which, once broken, will result in the stopping of the machine so that the malfunction can be corrected. A further important aspect of the control system is that it isinitiated by a box unit in position for transfer into the box wrapping machine, thus allowing an occasional missing box unit on the conveyor E without interrupting the operations upon a box already in the wrapping machine. I

In summary, threeinterrelated basic features herein disclosed increase the operating speed of the wrapping machine while maintaining complete control of the various operations, namely, the articulated drive arrangement'56 for the transfer carriagel, the discharge conveyor system N for interspacing the finished boxes and maintaining a controlled, orderly ejection thereof, and the FIG. 24 control system which monitors the feed, wrapping and discharge of the boxes, and interrupts the operation if malfunctions occur so as to prevent damage to the machine which could otherwise resultfrom the higher than usual velocities of the components.

More specifically, the articulated drive arrangement provides linear driving motion for the transfer carriage without tangential forces which would compound wear problems. Further, the drive system is compact, considerin g the long operating strokes, and decreases the size of the wrapping machine over many prior art machines. Most important, the center of mass of the articulated sweep arm is close to its center of rotation, thus minimizing rotational inertia and making it possible to rapidly start and stop the transfer carriage to clear any malfunctions with the least possible interruption of the overall operating time. The discharge conveyor maintains the orientation and control of the finished boxes, and delivers the box to a predetermined location at a predictable time, thereby facilitating further operations by other machinery. One of the most important features is that the finished boxes are kept separated by the discharge conveyor until they are discharged from the machine, thus preventing the boxes from adhering to each other even though the discharge rate of finished boxes is drastically increased, and the overall length of the machine is greatly reduced. The control system detects the progressive movement of the boxes and, in conjunction with the disclosed lowinertia drive system, is adapted to quickly'and automatically interrupt the operations until a jam or malfunction can be corrected. This eliminates damage'to the machine and reduces the number of scrap boxes, and allows the operator greater time for attendant duties away from the wrapping machine.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variationmay be made without departing from what is regarded to be the subject matter of the invention.

What is claimed is:

1. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, alinearly reciprocable transfer carriage for gripping and conveying the boxes along said rails,

- means for driving said carriage lying below and within the confines of said support rails, said means comprising a two-section elongate sweep arm articulated and overlapped at its longitudinal center for movement in a substantially horizontal plane under said transfer carriage, means for swinging one end section of said sweep arm in one direction from an initial position in which said sections are linearly aligned, means reacting on the free end section of said sweep arm for swinging said free end section in the opposite direction at the same rate of angular movement, a connecting point on said free end section following a linear path along the direction of movement of said transfer carriage, and means pivoting said free end section to said carriage at said connecting point. A

2. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and within the confines of said support rails, said means comprising a driven shaft arranged for oscillation through an arm to said. driven shaft, means connecting the free end i of the second lever of said sweep arm to said carriage, and means reacting on said second lever to swing said second lever in one direction while said first lever is swung in the opposite direction, the angular rate of movements of said first and second levers being equal so that the free end of said second lever follows a linear path.

3. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and within the confines of said support rails, said means comprising a driven shaft arranged for oscillation through an arc of 180 degrees, a radially extending first lever connected to said driven shaft for movement in a substantially horizontal plane, a stub shaft mounted on the free end of said first lever, a second lever having one end secured to said stub shaft, a pivot mounted on the free end of said second lever, the axes of said driven shaft and said stub shaft having the same interspacing as the axes of said stub shaft and said pivot, and reverse driving means connected to said stub shaft for rotating said stub shaft at double the speed of said driven shaft and in the opposite direction so that said pivot follows a linear path, and means connecting said pivot to said transfer carriage.

4. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and within the confines of said support rails, said means comprising an upright driven shaft, a fixed sprocket coaxial with said driven shaft, means for oscillating said driven shaft through an arc of substantially 180, a first lever mounted on said driven shaft, a stub shaft rotatably mounted on the free end of said first lever parallel to said driven shaft, a rotatable sprocket secured to said stub shaft, an endless chain trained around said sprockets, a second lever having one end secured to said stub shaft, and a pivotally mounted drive link interconnecting the free end of said second lever and said transfer carriage, said fixed sprocket having twice the number of teeth of said rotatable sprocket and said second lever having the same effective length as said first lever.

5. In a boxwrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and within the confines of said support rails, said means comprising a vertical driven shaft, a fixed bracket supporting the upper portion of said shaft, power means for reciprocating said shaft substantially one half turn in each direction, a first lever radially extending from the upper end of said driven shaft, a vertical stub shaft rotatably mounted on the free end of said first lever, a second riage.

lever having one end secured to said stub shaft, a connector bolt on the free end of said second lever in driving relation with said transfer carriage, a fixed sprocket secured to said bracket under said first lever, a rotatable sprocket having half the number of teeth of said fixed sprocket mounted on said stub shaft, and an endless roller chain trained around said sprockets, the interspacing of said connector bolt and said stub shaft being equal to the interspacing of said driven and stub shafts so that said connector bolt follows a linear path between said pickup and delivery positions of the carriage.

6. Apparatus according to claim 5 wherein said power means comprises a driven cam rotatable about a vertical axis, a camming face on one end of said cam, an elongate lever extending across said face, means pivotally mounting one end of said lever spaced from the rotational axis of said cam, a gear segment on the other end of said lever, a cam follower on said lever intermediate the ends thereof and engaged with said camming face to be moved toward and away from the rotational axis of said cam, and a gear secured to said driven shaft and meshed with said gear segment.

7. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and .within the confines of said support rails, said means comprising a vertical driven shaft, a fixed bracket supporting the upper portion of said shaft, power means for reciprocating said shaft substantially one half turn in each direction; said power means comprising a driven cam rotatable about a vertical axis, a camming face on one end of said cam, an elongate lever extending across said face, means pivotally mounting one end of said lever spaced from the rotational axis of said cam, a gear segment on the other end of said lever, a cam follower on said lever intermediate the ends thereof and engaged with said camming face to be moved toward and away from the rotational axis of said cam, and a gear secured to said driven shaft and meshed with said gear segment; a first lever radially extending from the upper end of said driven shaft, a vertical stub shaft rotatably mounted on the free end of said first lever, a second lever having one end secured to said stub shaft, a connector bolt on the free end of said second lever in driving relation with said transfer carriage, a fixed sprocket secured to said bracket under said first lever, a rotatable sprocket having half the number of teeth of said fixed sprocket mounted on said stub shaft, and an endless roller chain trained around said sprockets, the interspacing of said connector bolt and said stub shaft being equal to the interspacing of said driven and stub shafts so that said connector bolt follows a linear path between said pickup and delivery positions of the car-

Claims

1. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and within the confines of said support rails, said means comprising a two-section elongate sweep arm articulated and overlapped at its longitudinal center for movement in a substantially horizontal plane under said transfer carriage, means for swinging one end section of said sweep arm 180* in one direction from an initial position in which said sections are linearly aligned, means reacting on the free end section of said sweep arm for swinging said free end section in the opposite direction at the same rate of angular movement, a connecting point on said free end section following a linear path along the direction of movement of said transfer carriage, and means pivoting said free end section to said carriage at said connecting point.

2. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and within the confines of said support rails, said means comprising a driven shaft arranged for oscillation through an arc of 180 degrees, an articulated sweep arm movable in a horizontal plane and including initially aligned first and second pivotally interconnected levers of equal length, means connecting the first lever of said sweep arm to said driven shaft, means connecting the free end of the second lever of said sweep arm to said carriage, and means reacting on said second lever to swing said second lever in one direction while said first lever is swung in the opposite direction, the angular rate of movements of said first and second levers being equal so that the free end of said second lever follows a linear path.

4. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and within the confines of said support rails, said means comprising an upright driven shaft, a fixed sprocket coaxial with said driven shaft, means for oscillating said driven shaft through an arc of substantially 180*, a first lever mounted on said driven shaft, a stub shaft rotatably mounted on the free end of said first lever parallel to said driven shaft, a rotatable sprocket secured to said stub shaft, an endless chain trained around said sprockets, a second lever having one end secured to said stub shaft, and a pivotally mounted drive link interconnecting the free end of said second lever and said transfer carriage, said fixed sprocket having twice the number of teeth of said rotatable sprocket and said second lever having the same effective length as said first lever.

5. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and within the confines of said support rails, said means comprising a vertical driven shaft, a fixed bracket supporting the upper portion of said shaft, power means for reciprocating said shaft substantially one half turn in each direction, a first lever radially extending from the upper end of said driven shaft, a vertical stub shaft rotatably mounted on the free end of said first lever, a second lever having one end secured to said stub shaft, a connector bolt on the free end of said second lever in driving relation with said transfer carriage, a fixed sprocket secured to said bracket under said first lever, a rotatable sprocket having half the number of teeth of said fixed sprocket mounted on said stub shaft, and an endless roller chain trained around said sprockets, the interspacing of said connector bolt and said stub shaft being equal to the interspacing of said driven and stub shafts so that said connector bolt follows a linear path between said pickup and delivery positions of the carriage.

7. In a box wrapping machine, a pair of support rails for slidably supporting finished boxes for ejection from the machine, a linearly reciprocable transfer carriage for gripping and conveying the boxes along said rails, means for driving said carriage lying below and within the confines of said support rails, said means comprising a vertical driven shaft, a fixed bracket supporting the upper portion of said shaft, power means for reciprocating said shaft substantially one half turn in each direction; said power means comprising a driven cam rotatable about a vertical axis, a Camming face on one end of said cam, an elongate lever extending across said face, means pivotally mounting one end of said lever spaced from the rotational axis of said cam, a gear segment on the other end of said lever, a cam follower on said lever intermediate the ends thereof and engaged with said camming face to be moved toward and away from the rotational axis of said cam, and a gear secured to said driven shaft and meshed with said gear segment; a first lever radially extending from the upper end of said driven shaft, a vertical stub shaft rotatably mounted on the free end of said first lever, a second lever having one end secured to said stub shaft, a connector bolt on the free end of said second lever in driving relation with said transfer carriage, a fixed sprocket secured to said bracket under said first lever, a rotatable sprocket having half the number of teeth of said fixed sprocket mounted on said stub shaft, and an endless roller chain trained around said sprockets, the interspacing of said connector bolt and said stub shaft being equal to the interspacing of said driven and stub shafts so that said connector bolt follows a linear path between said pickup and delivery positions of the carriage.