US3927589A

US3927589A - Method and apparatus for opening letter envelopes

Info

Publication number: US3927589A
Authority: US
Inventors: Erwin J Emkjer; L Kenneth Tucker
Original assignee: KENEMATIC CO Inc
Current assignee: KENEMATIC CO Inc
Priority date: 1972-07-27
Filing date: 1973-07-09
Publication date: 1975-12-23
Anticipated expiration: 1992-12-23
Also published as: CA1014025A

Abstract

Apparatus and methods for opening letter envelopes or the like which comprise a feed hopper adapted to receive a stack of unopened envelopes lying on one another, an output hopper adapted to receive the envelopes after they have been opened, and means for successively transporting individual envelopes from the bottom of the stack in the feed hopper past a cutting means that is adapted to cut a longitudinal edge of the envelopes during transport. The apparatus and methods disclosed also include provision for urging the envelopes against the cutting means during transport, and a vacuum system is utilized for insuring efficient and reliable transporting of the envelopes and for capturing paper particles that are cut from the envelopes as they are opened.

Description

Umted States Patent 1191 1111 3,9

Emkjer et al. [4 Dec. 23, 1975 METHOD AND APPARATUS FOR OPENING 2,837,333 6/1958 Sindzinski 61 a! 271/12 1311111 mm 3,130,650 4/1964 Shields 271/12 X 3.l3$,l5l 611964 Link et al. 83ll00 X Inventors: Erwm J- ki 3,381,564 5/1968 Whiteford 83/912 Kenneth 'hlclter, Miami Lakes, both 3,545,136 6/1968 Simjian 83/912 X of Fla. [73] Asignee: Kenqnatic Company I Primary Examiner-J. M. Meister v Plantation, Fla. Attorney, Agent, or Firm-Wolfe, Hubbard, Leydtg, 22 Filed: July 9, 1973 08am [2l] Appl. No.1 377,427 ABSTRACT Dan Apparatus and methods for opening letter envelopes [63] ContmuauoiHn-part of Ser. No. 275.560. July 27, or the like which comprise a f hopper adapted to 1972' abandm'ed' receive a stack of unopened envelopes lying on one [52] us. 0. 83/23; 83/167; 83/3563; m g m fi [511 m 33/4"; 3255325; successively transporting individual envelopes from d a 3 6 6 6 6 6 v a n v u 6 v v a "g5 6 I I n I n 1 e I n a on in pat a Field Search I167, 356.3, 355, 417,

83/418 912 23 422 27 1mg means that 13 adapted to cut a longitudinal edge l3; Zzuzoz; of the envelopes during transport. The apparatus and 53138 R methods disclosed also include provision for urging the envelopes against the cutting means during trans- [56] References Cited port, and a vacuum system ismtilized for insuring effi- UNITED STATES YATEMS cient and reliable transporting of the envelopes and 1.109.958 9/1914 Bryant 83/912 X for capturing paper particles that are cut from the en- |,|55,727 3/1915 velopes as they are opened l,408.4l 5 2/ l 922 l,$33,l39 4/l925 Putt et a]. 83/3563 16 Claims, 12 Drawing Figures U.S. Patent Dec. 23, 1975 Sheet 1 of4 3,927,589

U.S. Patent Dec. 23, 1975 Sheet 2 of4 3,927,589

U.S. Patent Dec. 23, 1975 Sheet 3 of4 3,927,589

U.S. Patent Dec. 23, 1975 Sheet 4 of4 3,927,589

METHOD AND APPARATUS FOR OPENING LETTER ENVELOPES This application is a continuation-in-part of our copending parent application Ser. No. 275,560, filed July 27, i972. Said parent application Ser. No. 275,560, which is now abandoned, and the present application are assigned to a common assignee.

This invention relates to letter opening equipment and, more particularly, to methods and apparatus for automatically opening letter envelopes.

It is quite apparent that many companies and institutions that have a large volume of incoming mail experience considerable lost time and inconvenience in manually opening letter envelopes. In banks and other institutions where hundreds, or even thousands, of letters are received virtually every day, there exists a definite need for apparatus that will rapidly and automatically open letter envelopes without damaging their contents.

Accordingly, it is an object of the present invention to provide improved methods and apparatus for reliably and rapidly opening letter envelopes.

Another object of the present invention is to provide apparatus that is adapted to open envelopes of varying size and which does not require precise alignment of the envelopes as they are placed in the feed tray.

Yet another object of the invention is to provide automatic letter opening apparatus which cuts only a small portion of one longitudinal edge of an envelope to open it and thus substantially prohibits damage to the contents of the envelope.

Still another object lies in the provision of a vacuum system that produces a suction force for holding the letters being transported to the output tray or hopper and for capturing the paper particles that are cut from the envelopes during operation.

A more specific object of the present invention is to provide apparatus which successively transports individual envelopes from a feed hopper to an output hopper and is adapted to insure contact of one longitudinal edge against the cutting means during the transport of the individual letter envelopes.

Yet another specific object of the present invention is to provide apparatus for reducing the envelope-toenvelope friction of the envelope stack in the feed tray or hopper to insure that the envelopes are sequentially and successively transported past the cutting means.

Still another object of the present invention lies in the provision of automatically controlling the apparatus such that the apparatus will automatically shut down if a jam condition is experienced or when the output tray or hopper is full.

An additional object of the present invention is to provide an apparatus having an auxiliary cutting means which is adapted to open envelopes of extraordinary size and which are incapable of being transported from the feed hopper to the output hopper.

These and other objects and advantages of the present invention will become apparent from the ensuing specification and drawings, in which:

FIG. 1 is a perspective view of one embodiment of automatic letter opening apparatus incorporating features of the present invention;

FIG. 2 is an exploded perspective view of the appara tus of FIG. 1, with portions removed, and particularly illustrating one form of vacuum system itable for use with the present invention;

HO. 3 is a front view of a portion of the apparatus shown by way of example in FIG. 1;

FIG. 4 is a top plan view of a portion of the exemplary apparatus shown in FIG. I, here taken generally along the line 44 of FIG. 3;

FIG. 5 is an exploded, fragmentary perspective view, particularly illustrating the relationship of envelopes, transport belt, and the transport vacuum manifold in accordance with one exemplary form of the invention;

FIG. 6 is a partial perspective view, particularly illustrating cutting means and guide means suitable for use with the present invention;

FIG. 7 is a perspective plan view of a portion of the exemplary apparatus of FIG. I, particularly illustrating the drive means for the transport belt and cutting means;

FIG. 8 is a sectional view taken substantially along the line 8-8 of FIG. 3, here particularly illustrating details of the cutter and transport mechanisms;

FIG. 9 is an exploded, fragmentary perspective view similar to FIG. 5, but here depicting a slightly modified form of the present invention;

FIG. 10 is an enlarged, fragmentary perspective view of a modified form of vacuum system suitable for use with the present invention, here shown with the front of the housing removed and with the hinged cover open so as to expose the interior portions of the vacuum housing; and

FIGS. 11 and 12 are enlarged fragmentary side and plan views respectively illustrating details of an adjustable bleed mechanism utilized to control the lowvacuum side of the modified form of the system shown in FIGS. 9 and 10.

While the present invention is susceptible of various modifications and alternative forms, certain specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed but, on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as expressed in the appended claims.

Referring to the drawings and particularly FIGS. 1 and 2, apparatus 10 embodying features in accordance with one exemplary form of the present invention is shown having a feed hopper or tray 12 for receiving a stack of unopened envelopes 13, an output hopper or tray 14, and a transport means indicated generally at 16, which successively advances the lowest letter envelope from the input hopper to the output hopper and, in so doing, advances the letters past a cutting means which cuts a longitudinal edge from each of the envelopes as they are transported. The apparatus 10 has a centrally located control panel, indicated generally at 20, which controls the operation of the apparatus and also provides a visual monitor for indicating the various running conditions at any time.

To transport the letter envelopes from the feed hopper to the output hopper, and referring to FIGS. 2 and 3, a flexible endless belt 22 is provided which moves in a generally flat elongated loop, the upper portion of which extends from a point adjacent the lower left wall of the feed hopper 12 to a point adjacent the edge of the output hopper 14. The belt is positioned at an angle relative to a horizontal plane as shown in FIG. 3 so that the lowermost letter envelope being transported from the feed hopper will exit into the upper portion of the output hopper to enable accumulation of letters in the output hopper. A transport vacuum manifold 24 is provided immediately adjacent the upper portion of the loop and is adapted to communicate a vacuum supply to the underside of the upper flight of the belt 22. As best shown in FIG. 5, the manifold 24 is rectangular in cross section and has a narrow slot 25 extending substantially its entire length. The belt 22 is in turn provided with a number of apertures 26 which are in alignment with the slot 25 in the manifold 24 and thereby communicates vacuum to the envelopes being transported and proveds a holding force to insure that the letter envelopes are held to the belt and will thereby be advanced as the belt moves.

In keeping with an important aspect of one embodiment of the present invention and referring to FIGS. 2 and 5, the apertures 26 are preferably placed a predeten'nined distance from each side of a raised frictional surface 27 which may be latex rubber or the like. As soon as a pair of apertures 26 reach the upper portion of the endless loop during movement of the belt, the vacuum will engage the lowest envelope and advance it out of the feed hopper. The distance between adjacent raised surfaces 27 is greater than the average length of a business envelope, for example to 16 inches, so that as the belt moves the envelopes will be transported past the cutting means to the output tray with a reasonable spacing between adjacent envelopes.

While the shape of each of the raised surfaces 27 is not particularly critical and is shown in FIGS. 2 and 5 to be of a small circular configuration, it is important that the height of the surfaces be within the range of approximately l/l6 to A; inch so that as the belt advances and one of the raised surfaces comes into contact with the underside of the stack of envelopes 13 in the feed hopper, that it jar or jostle the stack. This is important in reducing the envelope-to-envelope friction that is present in the stack of envelopes I3 and enables the lowest envelope to be transported to the moving belt 22. In this connection, it has been observed that the vacuum force communicated through the apertures 26 is often insufficient to break away" a single lowermost envelope from the stack in the absence of a raised frictional surface such as the surface 27. It is also important in this embodiment of the invention that the distance between the surface 27 and the adjacent apertures 26 be at least about 1 inch and preferably between inch and 2 inches so that the raised surfaces will not interfere with the vacuum force holding the envelopes to the belt. It has been found that most letter envelopes are sufficiently flexible so that they will be held by the vacuum being communicated through the apertures when a Va inch high raised surface is used together with a 1% inch spacing between the raised surface and each of the apertures.

In the event the envelope-to-envelope friction in the feed hopper is not completely overcome by the jarring effect of the raised surface 27 of the transport belt, and two letters are simultaneously advanced, a bracket 28 having flexible rubber member 29 is located adjacent the opening in the feed hopper for the purpose of restraining the envelope that is riding on top of the lowermost envelope from being transported out of the feed tray 12 until the lower-most envelope has exited the feed tray.

Turning now to FIGS. 2, 6 and 8 it is preferred that the width of the belt 22 be less than the width of the envelopes being opened and, accordingly. a support transport guide 30 is provided in the same plane as the upper portion of the belt loop. A rear generally vertical transport guide 32 having an angled portion 34 is also provided to accurately position the envelopes as they pass the cutting means. The rear guide angled portion 34 is positioned immediately adjacent the supporting transport guide 30 and provides a downward component of force that tends to prevent the letter envelopes from climbing up the rear transport guide 32 during movement and thereby escape engagement with the cutting means.

To cut the longitudinal edge of the envelopes being transported, a circular toothed slitting or cutting saw is illustrated in FIG. 6, although an abrasive wheel or the like may be provided. The cutting saw is preferably about 3 inches in diameter and is rotated so that the cutting action is downwardly toward the support transport guide 30 during engagement with the envelope being opened. With the slitting saw rotating in this direction, the supporting transport guide functions much the same as an anvil and insures a uniform cutting action. As is clearly illustrated in FIG. 6, an opening 38 is provided in the angled portion 34 of the rear transport guide 32 and extends into the support transport guide 30 a predetermined distance. The cutting saw 36 is preferably positioned so that the outer periphery thereof extends beyond the rear transport guide a small distance. for example, about 300ths of an inch to insure that the cutting saw does not damage the contents of the letter being opened.

In keeping with the invention, the speed of the rotation of the cutting saw is preferably within the range of 5000 to 7000 rpm so that a clean cut of the longitudinal edge is made without providing excessive resistance to the movement of the letter being transported. To this end, it has been found with a 3 inch diameter cutting saw, that rotational speeds less than 5000 rpm have generated sufficient resistance to movement that a jam condition has often occurred. It should be understood that preferred rotational velocities would be somewhat different depending upon the diameter of the saw being used. It is also preferred that the axis of the slitting saw 36 be slightly above the supporting transport guide 30, for example, about one to two tenths of an inch. As is best shown in FIG. 3, the plane of the cutting saw 36 is perpendicular to the plane of the transport belt 22.

In accordance with another important aspect of the present invention, the transport belt 22 is positioned at an angle relative to the rear transport guide 32 as best shown in FIGS. 4 and 6, and is so positioned to urge the envelope into contact with the rear transport guide and therefore the cutting saw. While the angle is not deemed critical, and depends in part upon such factors as the distance between the feed and output hoppers, the exact placement of the cutting saw relative to the length of travel during transport and the like, the angle illustrated is preferably within the range of about l0 to 20. and is specifically illustrated to be about [5". It should be understood that letters can be placed in the feed hopper with some degree of misalignment so that when they are advanced by the transport belt. the angular orientation of the belt relative to the guide wall will urge the letter toward the rear transport guide 32 and thus insure contact of the longitudinal edge of the envelope with the cutting saw and thereby insure a generally uniform and reliable cutting action. In this connection, it was previously mentioned that the transport belt extended from a point adjacent or near the left edge of thereof. It should be understood that engagement by one of the raised surfaces at a location ahead of the center line of the envelope would frequently urge only the forward edge against the rear transport guide and the rear portion of the envelope would remain away from it, since no force would be applied to the rear portion tending to urge it to firmly abut against the rear transport guide.

ln keeping with yet another aspect of the present invention, the transport belt also has its edge near the front of the apparatus slightly higher than the opposite edge. As best shown in FIG. 2, the belt is positioned at an angle of about l5 along the entire upper portion of the loop around which it travels. This angular orientation has the effect of utilizing a component of gravitational force to more accurately align the letters in the Z5 feed tray since the continuous jostling of the letters by the raised surfaces tends to cause the letters to become more accurately aligned as they reach the lower position in the feed hopper or tray.

In keeping with the invention provision is made for opening envelopes of extraordinary size by the placement of a second cutting saw 40 near the front center portion of the apparatus. The cutting saw 40 is positioned adjacent a horizontal slot 42 which acts as a guide enabling an operator to place an edge of an envelope into the slot and slide it into contact with the cutting saw and thereby open the envelope. The cutting saw is preferably of substantially similar constructions as the cutting saw 36 previously described. To

drive the cutting saws 36 and 40, an electric motor or 40 the like 44 is provided with an output shaft 46 having a pair of pulleys 48, 50 attached thereto which drive flexible belts 52, 54 or the like which also ride on pulleys 56, 58 associted with the cutting saws 40 and 36,

respectively, as shown in FIGS. 3 and 7.

To drive the transport belt 22, another electric motor 60 or the like, is provided and has a pulley 62 attached to its drive shaft 64. A belt 66 rides on the pulley 62 as well as another pulley 68 that is attached to a shaft 70 which also has a drive roller 72 for driving the transport belt 22. At the opposite end of the elongated loop is a second freely rotatable roller 74 around which the transport belt is driven. Since the apparatus is designed for rapid operation, and will open up to 450 envelopes per minute, the transport belt moves the envelopes quite rapidly. Because of the upward inclination of the belt, one or more flexible deflectors 76 may be advantageously attached. near the output hopper to downwardly deflect the envelopes so that they will enter the output hopper.

Turning now to the vacuum system associated with the embodiment of the invention heretofore described, a vacuum motor (not shown) is located in an enclosure 80 positioned toward the rear of the apparatus, as

shown in FIG. 2. The motor is preferably of a size which will generate sufflcient vacuum to adequately hold the letters to the transport belt as well as provide a capability for capturing the paper particles that are cut from the envelopes during operation. In this connection, for example. a l horsepower electric vacuum *pro'ducing source capable of producing a vacuum of 'enclosure which preferably has a bag 97 therein to capture the particles.

Another flexible conduit or hose 96 may be provided to communicate vacuum to the back wall of the output hopper for the purpose of insuring correct alignment of a letter envelope receiving carton 98 which may be placed in the output hopper. It should be understood that if the carton 98 is not aligned with the opened envelopes being transported to the output hopper. the letters may strike the side walls of the carton and produce a jam condition in a very short time. The vacuum force will correct any slight misalignment caused by an operator who may have failed to accurately position the carton during its insertion into the output hopper.

In keeping with the present invention, the exemplary apparatus has an electrical control system which is of conventional design and therefore has not been shown in detail. Referring to FIG. I, the control panel 20 includes a resettable counter 102, thumbwheel switches 103 for preselecting the quantity of open envelopes to be delivered to the envelope receiving carton 98, a main power switch 104, a cutter switch 106, a transport switch 108, full indicator light and a jam indicator light 112. To start the apparatus, the operator merely inserts a stack of letters in the input of feed hopper, depresses the main power switch, which must be on for any of the motors to be operable. The operator then depresses the cutter switch which turns on the vacuum system as well as the cutter drive motor 44. Afler the cutter switch 106 is turned on. the operator merely depresses the transport switch 108 which turns on motor 60 and causes the transport belt 22 to begin moving. Referring to FIG. 3, a jam indicator circuit comprising a light source 114 and a photoelectric sensor 116 is positioned immediately adjacent the transport belt near the output hopper 14. A timing circuit is associated with the photoelectric circuit so that a jam condition will not be indicated unless a letter envelope opens the photoelectriccircuit for a predetermined time which is longer than the time necessary for a single letter to pass during operation. If, for example, a jam condition is experienced, the envelopes will block the photoelectric circuit for a time longer than should be required and this condition will cause the transport motor 60, the cutter motor 44 and the vacuum system to shut off. A second photoelectric circuit comprising a photocell [l8 and another light source (not shown) is positioned near the upper portion of the output hopper and is effective to indicate when the carton 98 is full. Breakage of the photoelectric circuit will shut off the transport motor and thereby stop feeding of envelopes through the apparatus. At this point, the operator may remove the filled carton of opened envelopes, insert another carton. and depress the transport button causing the continued operation of the 7 apparatus.

While the invention has heretofore been described in connection with an embodiment utilizing a raised frictional surface--e.g., the surface as shown in FIG. -interposed between a pair of vacuum transmitting apertures 26, it is not limited to that specific construction and other embodiments may be employed to effect the desired jostling of the stack of envelopes in the feed hopper 12 of FIG. 1. For example, an alternative construction that has been found to be quite satisfactory is illustrated by way of example in FIG. 9.

In accordance with this altgmative form of the invention as shown in FIG. 9, the endless transport belt 22 is provided with a series of vacuum transmitting apertures spaced apart by a distance somewhat greater than the average length of a business enveIope--for example, 15 to 16 inches apart--one such aperture being depicted in FIG. 9 at 120. A raised friction surface, here in the form of a flat square pad 121 of natural rubber or the like having a central aperture I22 somewhat larger than the belt aperture 120, is bonded to the belt 22 with the two apertures I20, 122 being coaxial. As in the form of the invention heretofore described in connection with FIG. 5, the particular dimensions employed are not critical, but advantageous results have been obtained utilizing a pad 12] approximately l /zinches square, l/l6 to V5 inch high, and having an aperture 122 witha 1 inch diameter coaxial with a 5% inch diameter aperture 120 in the belt 22.

It will be appreciated upon comparison of the embodiment of the invention shown in FIG. 5 with that shown in FIG. 9 that, whereas the former provides a pair of vacuum transmitting apertures on either side of a raised frictional surface, the latter provides raised frictional surfaces on either side of a vacuum transmitting aperture. In both cases, however, the net effect is that the raised frictional surface tends to jostle the stack of envelopes in the feed hopper (e.g., hopper 12 in FIG. I) so as to separate the lowermost envelope from the stack, while the aperture(s) pennits communication of sufiicient vacuum to firmly clamp the lowennost envelope 13 to the belt 22.

In order to permit even more envelopes 13 to be stacked in the feed hopper 12 (FIG. I), while at the e time insuring efficient and reliable removal of the lo'wermost envelope from the stack and subsequent processing thereof irrespective of whether the system is being utilized to open relatively stiff envelopes of relatively thin, light-weight envelopes, a modified vacuum system such as illustrated in FIGS. 9-12 may be employed.

In keeping with this form of the invention, provision is made for allowing a relatively high vacuum to be communicated to the envelope being stripped from the bottom of the stack in the feed hopper, and a relatively lower vacuum to be communicated to the envelope as it progresses along the transport mechanism. To this end, and as best illustrated in FIG. 9, the transport vacuum manifold 24 is again provided with a narrow slot 25 extending substantially its entire length. However, in this form of the invention, the manifold 24 is provided with a transverse baffle 124 at approximately the midpoint, thus dividing the manifold into two separate chambers--viz., a relatively high vacuum chamber 125 and a relatively low vacuum chamber I26. The arrangement is such that as the belt 22 moves along its endless path, a raised surface thereon will engage the stack of envelopes I3 in the feed hopper 12 (FIG. 1),

thereby jostling the stack and separating the lowermost envelope therefrom. Relatively high vacuum will be communicated from chamber through the coaxial apertures I20, I22 (or through the pair of apertures 26 if this modified vacuum system is used with the belt shown in FIG. 5) to firmly clamp the envelope to the belt and strip it from the stack. This permits more envelopes to be stacked in the feed hopper 12 (FIG. I).

In carrying out this modified form of the invention, a vacuum motor I28 is located in an enclosure 129, as best shown in FIG. 10. As the ensuing description proceeds, it will be understood that the enclosure 129 shown in FIG. I0 and the vacuum system contained therein is somewhat similar in function and intended to replace the enclosure 80 and associated vacuum system previously described in connection with FIG. 2. The arrangement is such that the relatively high vacuum drawn by motor 128 is communicated through a hose or flexible conduit 130 directly connecting the motor 128 (FIG. 10) to the high vacuum chamber 125 (FIG. 9) in the transport manifold 24. At the same time, the relatively high vacuum drawn by the motor I28 is also communicated to a closed chamber (FIG. I0) located within enclosure I29 through a port 132. Those skilled in the art will appreciate that while the chamber I31 is shown open in FIG. 10, during operation of the equipment the cover 134 of the enclosure 120 would be moved to the closed position, thereby closing chamber 131. 4

In keeping with this aspect of this invention provision is made for controllably regulating the degree of vacuum maintained within chamber 131. To accomplish this, an adjustable vacuum regulator, generally indicated at I35 (FIG. 10-12), is mounted in the cover 134 for permitting controlled bleeding of ambient air into the chamber 131, thereby controllably reducing the vacuum level therein. In the (exemplary system, the regulator 135 comprises a metalbacked rubber disc 136 which is slidably mounted on a bolt 138 that passes through the cover 135 coaxial with a circular array of bleed ports I39 fonned in the cover. The disc 136 is adjustably biased into contact with the bottom of the cover 134 in underlying sealing relation to the ports I39 by means of a spring 140 which surrounds the bolt I38 and is bottomed at its upper end on the under surface of the disc I36 and at its lower end on a nut I41 threadably engaged with the bolt 138. By threading the nut I41 onto the bolt 138, the spring I40 is compressed, thereby increasing the pressure with which the pad I36 is urged into sealing relation with the bleed ports 139, reducing the flow of ambient air into the chamber I31, and thus increasing the vacuum level maintained in the chamber. Conversely, when the nut 141 is unthreaded, the spring is extended, thereby reducing the pressure with which the pad is urged into sealing engagement with the ports 139. This serves to let atmospheric pressure overcome, to a contollable extent dependent upon the spring tension, the spring bias, thereby permitting a controlled amount of air to bleed into chamber 131 and reducing the vacuum level therein. The controlled and reduced vacuum level is then communicated to the relatively low vacuum chamber 126 in the transport manifold 24 by means of a hose or other flexible conduit I42 (FIGS. 9 and 10).

It has been found in the practice of the present invention that the arrangement of a 1 inch diameter aperture (FIG. 9) in the raised frictional surface 121 overlying and coaxial with a /2 inch diameter aperture 120 in the belt 22, permits the envelope 13 being transported to be firmly clamped to the belt while, at the same time, there is a rapid transition from high to low vacuum as the

apertures

120, 122 pass the baffle [24 separating the chambers [25 and 126. Moreover, the provision of the low vacuum side of the system imparts greater flexibility to the system since it can be more readily used with thin, light-weight envelopes.

In keeping with the present invention, the enclosure [29 serves also to house a vacuum bag 144 (FIG. coupled to a second vacuum motor 145. The vacuum drawn in the bag 144 is communicated to a manifold 146 having a plurality of hose connections; for example,

connections

148, 149 and 150. The

connections

148, 149 may be coupled directly to hoses (such as the hoses 92, 94 shown in FIG. 2) for removal of chips fonned during envelope cutting operations; such chips being collected in the bag 144 for subsequent discarding. Similary, the connection 150 may be coupled directly to a hose (sucy as the hose 96 shown in FIG. 2) for holding the envelope container 98 in place as previously described.

Thus, it should be readily apparent that automatic letter envelope opening apparatus and methods have been described which provide reliable and fast operation and which satisfy all of the aforementioned objects and advantages.

We claim as our invention:

1. Apparatus for opening letter envelopes or the like, comprising, in combination:

a feed hopper adapted to receive a stack of unopened envelopes lying on one another;

an output hopper adapted to receive said envelopes after they have been opened;

a flexible transport belt movable around a loop, the upper portion of which extends from beneath the upstream side of said feed hopper to a point adjacent said output hopper for successively transporting individual envelopes from the bottom of said stack in said feed hopper to said output hopper;

means for guiding said envelopes as they are transported to said output hopper, said guide means including a support transport guide portion lying substantially in the same plane as said upper portion of said belt and a generally vertical rear transport guide portion intersecting said support guide portion for accurately positioning said envelopes for engagement with said cutting means during movement of said envelopes, said generally vertical rear transport guide portion having a portion near said support guide portion that is positioned at an acute angle relative to said support guide portion so that said envelopes are restrained from moving upwardly from said support guide portion during transport thereof;

means for cutting a longitudinal edge of said envelopes as they are transported to said output hopper, said cutting means being located adjacent said guide means;

means for urging said longitudinal edge of said envelope to firmly abut against said guide means during transport to insure substantially complete cutting of said longitudinal edge; and

a vacuum manifold and a vacuum supply connected thereto, said manifold being positioned immediately below the upper portion of said loop and extending longitudinally from a point below said stack in said feed hopper to a point beyond said 10 cutting means, said belt including at least one aperture therein for communicating vacuum to said envelopes for holding said envelopes to said belt during transport thereof from said feed hopper stack, past said cutting means, and to a point beyond said cutting means.

2. Apparatus as defined in claim 1 wherein said transport belt is angled downwardly toward the rear of said apparatus so that envelopes in said feed hopper tend to move toward the rear thereof due to the jostling action caused by the raised surfaces contacting the bottom of said stack.

3. Apparatus for opening letter envelopes or the like,

comprising, in combination:

an output hopper adapted to receive said envelopes after they have been opened;

a flexible transport belt movable around a loop, the upper portion of which extends from beneath the upstream side of said feed hopper to a point adjacent said output hopper for successively transporting indivdual envelopes from the bottom of said stack in said feed hopper to said output hopper;

means for guiding said envelopes as they are transported to said output hopper;

a vacuum manifold and a vacuum supply connected thereto, said manifold being positioned immediately below the upper portion of said loop and extending longitudinally from a point below said stack in said feed hopper to a point beyond said cutting means,

said belt being formed with pairs of apertures for communicating vacuum to said envelopes for holding said envelopes to said belt during transport thereof from said feed hopper stack, past said cutting means, and to a point beyond said cutting means, said apertures of each pair being located in predetermined relation on opposite sides of a raised frictional surface, said raised surfaces being spaced apart from one another along the length of said belt a predetermined distance which is greater than the length of said envelopes, said raised surfaces being effective to jostle said stack of envelopes in said supply hopper during movement of said belt to reduce the envelope-to-envelope friction within said stack and enable the lowermost envelope to be transported toward said output hopper.

4. Apparatus as defined in claim 3 wherein said predetermined distance is within the range of about 1 and 2 inches.

5. Apparatus for opening letter envelopes or the like, comprising, in combination:

an output hopper adapted to receive said envelopes after they have been opened;

a flexible transport belt movable around a loop, the upper portion of which extends from beneath the 1 l upstream side of said feed hopper to a point adjacent said output hopper for successively transporting individual envelopes from the bottom of said stack in said feed hopper to said output hopper; means for guiding said envelopes as they are transported to said output hopper;

means for cutting a longitudinal edge of said envelopes as they are transported to said output hopper. said cutting means being located adjacent said guide means;

said belt being positioned at an acute angle relative to said guide means so that said longitudinal edge of each of said envelopes is urged against said guide means during transport to insure substantially complete cutting of said longitudinal edge;

a vacuum manifold and a vacuum supply connected thereto. said manifold being positioned immediately below the upper portion of said loop and extending longitudinally from a point below said stack in said feed hopper to a point beyond said cutting means, said belt including at least one aperture therein for communicating vacuum to said envelopes for holding said envelopes to said belt during transport thereof from said feed hopper stack, past said cutting means, and to a point beyond said cutting means; and

a thin pad bonded to said belt and having an aperture therein coaxial with the aperture in said belt, said pad forming a raised frictional surface for jostling said stack of envelopes in said supply hopper during movement of said belt so as to reduce the envelope-to-envelope friction within said stack and enable the lowermost envelope to be transported toward said output hopper.

6. Apparatus as defined in claim 5 wherein the aper ture in said pad is larger than the aperture in said belt.

7.. Apparatus as defined in claim 6 wherein the aperture in said pad is on the order of one inch in diameter and the aperture in said belt is on the order of one-half inch in diameter.

8. Apparatus for opening letter envelopes or the like.

comprising, in combination:

an output hopper adapted to receive said hopper envelopes after they have been opened;

means for guiding said envelopes as they are transported to said output hopper;

means for urging said longitudinal edge of said envelope to firmly abut against said guide means during transport to insure substantially complete cutting of said longitudinal edge;

a vacuum manifold fomied with two chambers, said chambers each being connected to a vacuum supply, said manifold being positioned immediately below the upper portion of said loop and extending longitudinally from a point below said stack in said feed hopper to a point beyond said cutting means (ill with one of said chambers being at the feed hopper end of said manifold and the other of said chambers being at the opposite end of said manifold, said chamber at the feed hopper end of said manifold being maintained at a higher vacuum level than the chamber at the opposite end of said manifold. and

said belt including at least one aperture therein for communicating vacuum to said envelopes for holding said envelopes to said belt during transport thereof from said feed hopper stack, past said cutting means, and to a point beyond said cutting means.

9. Apparatus as defined in claim 8 wherein an enclosure connected to said vacuum supply is positioned adjacent said cutting means so that paper particles removed from said envelopes during opening thereof are captured.

10. Apparatus as defined in claim 8 wherein the vacuum level in said other chamber is adjustable.

11. Apparatus as defined in claim 8 wherein said two vacuum chambers are connected to a common vacuum supply.

12. Apparatus as defined in claim 1 wherein an adjustable vacuum regulator is included in the connection between said vacuum supply and said other chamber.

13. Apparatus for opening letter envelopes or the like, comprising, in combination:

an output hopper adapted to receive said envelopes after they have been opened;

means for successively transporting individual envelopes from the bottom of said stack in said feed hopper to said output hopper;

means for guiding said envelopes as they are transported to said output hopper;

a cutting saw positoned adjacent said guide means and being rotatable in a direction downwardly toward said envelopes for cutting off the longitudinal edges thereof;

means for urging the longitudinal edges of said envelopes to firmly abut against said guide means during transport to insure substantially complete cutting of said longitudinal edge; and

an auxiliary cutting wheel at the front of said apparatus for cutting a longitudinal edge of envelopes of extraordinary size.

14. Apparatus as defined in claim 13 wherein said belt is positioned at an acute angle relative to said guide means so that said longitudinal edge of each of said envelopes is urged against said guide means prior to reaching said cutting means during transport to said output hopper.

15. A method of opening letter envelopes or the like, comprising the steps of: the envelopes lying on one another;

advancing a flexible belt around an elongated closed loop, said belt having one or more apertures formed therein, said belt also having one or more raised surfaces thereon adapted to jostle the bottom of the stack and reduce the envelope-toenvelope friction enabling the lowermost envelopes to be successively transported out of said feed hopper;

moving said belt about said loop in such manner that it converges toward a guide means during its advancement and thereby urges said envelopes into contact with said guide means to accurately position said envelopes for cutting a lodgtidinal edge therefrom;

cutting a longitudinal edge of said envelopes as they are advanced and thereby opening said envelopes;

depositing said opened envelopes in an output hopper; and applying a suction force only through apertures in said belt located at points rearwardly of the transverse center line of each said envelope so that the envelopes are held to said belt as said belt advances the envelopes from said feed hopper and the entire longitudinal edge of each envelope is urged against said guide means as the belt advances the envelopes through said cutting operation and to a point in the vicinity of said output hopper.

16. A method of opening letter envelopes or the like,

comprising the steps of:

placing a stack of unopened envelopes in a feed hopper with the envelopes lying on one another;

advancing a flexible belt around an elongated closed loop, said belt having one or more raised surfaces therein adapted to jostle the bottom of the stack and reduce the envelope-to-envelope friction enabling the lowermost envelopes to be successively transported out of said feed hopper;

urging said envelopes against a guide means to accurately position said envelopes and enable a longitudinal edge to be cut therefrom;

depositing said opened envelopes in an output hopper;

applying a suction force through one or more apertures in said belt to hold said envelopes against said belt as said belt advances the envelopes from said feed hopper, through said cutting operation, and to a point in the vicinity of said output hopper; and

applying a greater suction force to said envelopes in the vicinity of said feed hopper than in the vicinities of said cutter and output hopper.

Claims

1. Apparatus for opening letter envelopes or the like, comprising, in combination: a feed hopper adapted to receive a stack of unopened envelopes lying on one another; an output hopper adapted to receive said envelopes after they have been opened; a flexible transport belt movable around a loop, the upper portion of which extends from beneath the upstream side of said feed hopper to a point adjacent said output hopper for successively transporting individual envelopes from the bottom of said stack in said feed hopper to said output hopper; means for guiding said envelopes as they are transported to said output hopper, said guide means including a support transport guide portion lying substantially in the same plane as said upper portion of said belt and a generally vertical rear transport guide portion intersecting said support guide portion for accurately positioning said envelopes for engagement with said cutting means during movement of said envelopes, said generally vertical rear transport guide portion having a portion near said support guide portion that is positioned at an acute angle relative to said support guide portion so that said envelopes are restrained from moving upwardly from said support guide portion during transport thereof; means for cutting a longitudinal edge of said envelopes as they are transported to said output hopper, said cutting means being located adjacent said guide means; means for urging said longitudinal edge of said envelope to firmly abut against said guide means during transport to insure substantially complete cutting of said longitudinal edge; and a vacuum manifold and a vacuum supply connected thereto, said manifold being positioned immediately below the upper portion of said loop and extending longitudinally from a point below said stack in said feed hopper to a point beyond said cutting means, said belt including at least one aperture therein for communicating vacuum to said envelopes for holding said envelopes to said belt during transport thereof from said feed hopper stack, past said cutting means, and to a point beyond said cutting means.

3. Apparatus for opening letter envelopes or the like, comprising, in combination: a feed hopper adapted to receive a stack of unopened envelopes lying on one another; an output hopper adapted to receive said envelopes after they have been opened; a flexible transport belt movable around a loop, the upper portion of which extends from beneath the upstream side of said feed hopper to a point adjacent said output hopper for successively transporting indivdual envelopes from the bottom of said stack in said feed hopper to said output hopper; means for guiding said envelopes as they are transported to said output hopper; means for cutting a longitudinal edge of said envelopes as they are transported to said output hopper, said cutting means being located adjacent said guide means; means for urging said longitudinal edge of said envelope to firmly abut against said guide means during transport to insure substantially complete cutting of said longitudinal edge; and a vacuum manifold and a vacuum supply connected thereto, said manifold being positioned immediately below the upper portion of said loop and extending longitudinally from a point below said stack in said feed hopper to a point beyond said cutting means, said belt being formed with pairs of apertures for communicating vacuum to said envelopes for holding said envelopes to said belt during transport thereof from said feed hopper stack, past said cutting means, and to a point beyond said cutting means, said apertures of each pair being located in predetermined relation on opposite sides of a raised frictional surface, said raised surfaces being spaced apart from one another along the length of said belt a predetermined distance which is greater than the length of said envelopes, said raised surfaces being effective to jostle said stack of envelopes in said supply hopper during movement of said belt to reduce the envelope-to-envelope friction within said stack and enable the lowermost envelope to be transported toward said output hopper. Pg,22

5. Apparatus for opening letter envelopes or the like, comprising, in combination: a feed hopper adapted to receive a stack of unopened envelopes lying on one another; an output hopper adapted to receive said envelopes after they have been opened; a flexible transport belt movable around a loop, the upper portion of which extends from beneath the upstream side of said feed hopper to a point adjacent said output hopper for successively transporting individual envelopes from the bottom of said stack in said feed hopper to said output hopper; means for guiding said envelopes as they are transported to said output hopper; means for cutting a longitudinal edge of said envelopes as they are transported to said output hopper, said cutting means being located adjacent said guide means; said belt being positioned at an acute angle relative to said guide means so that said longitudinal edge of each of said envelopes is urged against said guide means during transport to insure substantially complete cutting of said longitudinal edge; a vacuum manifold and a vacuum supply connected thereto, said manifold being positioned immediately below the upper portion of said loop and extending longitudinally from a point below said stack in said feed hopper to a point beyond said cutting means, said belt including at least one aperture therein for communicating vacuum to said envelopes for holding said envelopes to said belt during transport thereof from said feed hopper stack, past said cutting means, and to a point beyond said cutting means; and a thin pad bonded to said belt and having an aperture therein coaxial with the aperture in said belt, said pad forming a raised frictional surface for jostling said stack of envelopes in said supply hopper during movement of said belt so as to reduce the envelope-to-envelope friction within said stack and enable the lowermost envelope to be transported toward said output hopper.

6. Apparatus as defined in claim 5 wherein the aperture in said pad is larger than the aperture in said belt. 7.. Apparatus as defined in claim 6 wherein the aperture in said pad is on the order of one inch in diameter and the aperture in said belt is on the order of one-half inch in diameter.

8. Apparatus for opening letter envelopes or the like, comprising, in combination: a feed hopper adapted to receive a stack of unopened envelopes lying on one another; an output hopper adapted to receive said hopper envelopes after they have been opened; a flexible transport belt movable around a loop, the upper portion of which extends from beneath the upstream side of said feed hopper to a point adjacent said output hopper for successively transporting individual envelopes from the bottom of said stack in said feed hopper to said output hopper; means for guiding said envelopes as they are transported to said output hopper; means for cutting a longitudinal edge of said envelopes as they are transported to said output hopper, said cutting means being located adjacent said guide means; means for urging said longitudinal edge of said envelope to firmly abut against said guide means during transport to insure substantially complete cutting of said longitudinal edge; a vacuum manifold formed with two chambers, said chambers each being connected to a vacuum supply, said manifold being positioned immediately below the upper portion of said loop and extending longitudinally from a point below said stack in said feed hopper to a point beyond said cutting means with one of said chambers being at the feed hopper end of said manifold and the other of said chambers being at the opposite end of said manifold, said chamber at the feed hopper end of said manifold being maintained at a higher vacuum level than the chamber at the opposite end of said manifold, and said belt including at least one aperture therein for communicating vacuum to said envelopes for holding said envelopes to said belt during transport thereof from said feed hopper stack, past said cutting means, and to a point beyond said cutting means.

13. Apparatus for opening letter envelopes or the like, comprising, in combination: a feed hopper adapted to receive a stack of unopened envelopes lying on one another; an output hopper adapted to receive said envelopes after they have been opened; means for successively transporting individual envelopes from the bottom of said stack in said feed hopper to said output hopper; means for guiding said envelopes as they are transported to said output hopper; a cutting saw positoned adjacent said guide means and being rotatable in a direction downwardly toward said envelopes for cutting off the longitudinal edges thereof; means for urging the longitudinal edges of said envelopes to firmly abut against said guide means during transport to insure substantially complete cutting of said longitudinal edge; and an auxiliary cutting wheel at the front of said apparatus for cutting a longitudinal edge of envelopes of extraordinary size.

15. A method of opening letter envelopes or the like, comprising the steps of: the envelopes lying on one another; advancing a flexible belt around an elongated closed loop, said belt having one or more apertures formed therein, said belt also having one or more raised surfaces thereon adapted to jostle the bottom of the stack and reduce the envelope-to-envelope friction enabling the lowermost envelopes to be successively transported out of said feed hopper; moving said belt about said loop in such manner that it converges toward a guide means during its advancement and thereby urges said envelopes into contact with said guide means to accurately position said envelopes for cutting a longtidinal edge therefrom; cutting a longitudinal edge of said envelopes as they are advanced and thereby opening said envelopes; depositing said opened envelopes in an output hopper; and applying a suction force only through apertures in said belt located at points rearwardly of the transverse center line of each said envelope so that the envelopes are held to said belt as said belt advances the envelopes from said feed hopper and the entire longitudinal edge of each envelope is urged against said guide means as the belt advances the envelopes through said cutting operation and to a point in the vicinity of said output hopper.

16. A method of opening letter envelopes or the like, comprising the steps of: placing a stack of unopened envelopes in a feed hopper with the envelopes lying on one another; advancing a flexible belt around an elongated closed loop, said belt having one or more raised surfaces therein adapted to jostle the bottom of the stack and reduce the envelope-to-envelope friction enabling the lowermost envelopes to be successively transported out of said feed hopper; urging said envelopes against a guide means to accurately position said Envelopes and enable a longitudinal edge to be cut therefrom; cutting a longitudinal edge of said envelopes as they are advanced and thereby opening said envelopes; depositing said opened envelopes in an output hopper; applying a suction force through one or more apertures in said belt to hold said envelopes against said belt as said belt advances the envelopes from said feed hopper, through said cutting operation, and to a point in the vicinity of said output hopper; and applying a greater suction force to said envelopes in the vicinity of said feed hopper than in the vicinities of said cutter and output hopper.