Envelope opening mechanism and method
United States Patent Russell et al. l Apr. 8, 1975 i l ENVELOPE OPENING MECHANISM AND [57] ABSTRACT METH Apparatus and method for opening envelopes by car- 751 mentors: Robert J. RUSSQIL Laurel springs honizing the edges thereof by the application of heat Edwin R Heme BimnnghdnL to the respective edges. in one embodiment of the in- AILL ventlon. the three respective edges of the envelope are I carbonized by passing the edges through a passageway Ahblgneei Ken) Corporatmm Worry Hill. vvithin which radiant heat is generated and directed against or focused upon the edge of the envelope 23] pncd: Sept 2L 1970 being treated. in the overall system. a pick-up arrangement is employed which removes the envelope from a 1 pp N05 741,60 feeding magazine and directs the envelopes to a settle- Related US. Application Dma down station. At the settledovvn station, the envelopes Cuminumiumwpun Of SN NO 7&#39;6. p I6. are orientated for passage into opposed belts which 1969 Pm N x 590 S48 convey the envelopes sequentially through three burner sections interposed between which are flip- [Q3] Us Cl 51/18] R over mechanisms which rotate the envelope 90 to a [m C g (n/00 present the next adjacent edge for carhonizing. At the g Fie&#39;ld i i i i 83/9 I end of the burner sections. a third flip-over rotates the i i i envelopes into position in a flip-down mechanism [s6] References cued which delivers the envelope to a differential roller with its uncarhonized edge in a trailing position. The  
 UNITED STATES PATENTS differential roller assembly includes a conveyor belt 2355,459 8944 29/349 and a roller with a brake which is selectively actuated 343L629 5/1964 Knfpot&#39;ch R in response to the appearance of the envelope in the ig opening mechanism to exert a shearing force on the Primary E.u1mincr-Travis S. McGehee envelope and lay back an edge thereof exposing the contents.  
 8 Claims, 7 Drawing Figures muZmDm QZN saw 1 or 3 ATENIEDAPR 8 i9? 2300 mHFrmm E: OZN  
 INVENTORS ROBERT J. RUSSELL EDWIN J. PIER ATTORNEY HOABANOQ QNIGVO&#39;I INVENTORS ROBERT J. RUSSELL EDWIN J. PIERCE M 4 0W ATTORNEY PATENTEDAPR 8l975 PATENTEDA 81975 SFLEI 3 Bf 3 INVENTORS ROBERT J. RUSSELL EDWIN J.P|ERCE ATTORNEY ENVELOPE OPENING MECHANISM AND METHOD The present application is a continuation-in-part of application Ser. No. 817.619 filed Apr. 1b. was. now LLS. Pat. No. 3.590.548.  
 BACKGROUND OF IN\&#39;ENT1ON Many businesses today. for example. the large credit card companies. experience extremely large volumes of mail every week which needs to be opened. The apparently simple task of opening the envelopes becomes a rather major task and extremely expensive when large volumes of mail are involved. In some businesses. literally millions of pieces of mail are received weekly and must be physically opened by personnel.  
  A number of machines have been proposed to open the mail and operate on a variety of different principles. For example. there are a number of machines which operate on the principle of cutters which slice one or more edges of the envelopes. One of the drawbacks of these machines is that. quite frequently. the contents of the envelopes are sliced as well.  
 Another type of apparatus is the abrading type which. rather than slicing the envelope. abrades the edge thus weakening it. The problems inherent in this type ofdevice is that the edges of the envelope must be straight or certain sections thereof will not be suffieiently weakened for opening. Also. an apparatus of this type is slow in its operation.  
  In yet another type of apparatus. an electric spark is employed to weaken the edge as disclosed in US. Pat. No. 3.116.718 issued Jan 7. 1964 to Krupotich et al. This type of apparatus has found little success. The greatest problem encountered in this type of opening apparatus is the registry of the edge of the envelope with the spark.  
  Another method of opening envelopes which has been developed is that of applying heat to the edges of the envelope by means of a contact between the envelope and a heated guide rail. The heat from the guide rail will carbonize and weaken the edges of the envelope. This method and apparatus for carrying out the method are disclosed in Krupotich US. Pat. No. 3.132.629 issued May 12. 1964.  
  An improved method over Krupotich U.S. Pat. No. 3.132.629 is disclosed in this applications parent copending application by Edwin F. Pierce and Robert J. Russell Ser. No. 817.619 filed in Apr. 16. 1969. In the parent case. heated gas is employed to carbonize the edges of the envelope. The present invention is concerned with further developments and improvements over the co-pending parent application.  
 SUMMARY AND OBJECTS OF INVENTION The apparatus and methods of the present invention are concerned with further improvements to the general concept ofopening envelopes by the application of heat to the edges thereof and it is a principle object of the present invention to apply the heat to the edges of the envelope by means of radiant heat alone or in combination with heated air or gas.  
  It is another object of the present invention to improve the handling and passage of the envelopes into the conveyor systems which carry the envelopes through the burner sections by means of a settle-down station positioned in advance of the conveyor belts.  
  The foregoing objects are carried out by the present invention by utilizing three sets of burner assemblies through which each of the three edges ofthe envelopes to be weakened are sequentially conveyed. Opposed conveyor belts carry the envelopes through the burner assemblies. At the end of each of the assemblies. a flipover mechanism rotates the envelope 90 degrees pre paratory to passage through the next assembly thus positioning the next adjacent edge of the envelope for passage through the following burner assembly.  
  In one embodiment of the invention. the burner assembly includes an elongate passageway through which the edge of the envelope to be carbonized passes. The passageway is suitably surrounded by insulation so as to isolate the passageway from the atmosphere and to maintain a static air condition within the passageway. One or more heated elements are associated with the passageway. The heating elements raise the temperature of the passageway to a temperature at which the passageway radiates sufficient heat to the edge of the envelope to carbonize the edge as the envelope moves through the passageway. Additionally. the air within the passageway will become heated to carbonizing temperatures and aid in carbonizing the edge of the envelope.  
  In a second embodiment of the burner assembly of the present invention. radiant heat only to carbonize the edge of the envelope is applied to the edge within the passageway by means of a radiant heat generator disposed within the passageway and spaced from the edge of the envelope. Suitable reflectors may be employed to focus or direct the radiant energy to the immediate vicinity of the edge of the envelope. Optical focusing means, such as lenses or the like. may also be employed intermediate the radiation generator and the edge of the envelope to focus the radiant energy onto the edge of the envelope.  
  At the end of the carbonization sequence for all three edges of the envelope. a third flip-over mechanism rotates the envelope into contact with a turn down mech anism which places the envelopes onto a conveyor with its unweakened edge in a trailing position. The envelopes then pass through a differential opener which includes a conveyor belt and a roller. The roller has a brake assembly associated with the roller which is momentarily and sequentially applied in response to a photocell mechanism which senses the appearance of an envelope in the assembly. The braking action on the roller serves to provide a shearing force on the weakened edges of the envelope thus rolling back one edge of the envelope to expose the contents.  
  The present invention also includes a mechanism for pickingup and passing the envelopes into the first burner assembly. This includes a pick-up assembly which removes the envelopes from a loading magazine and passes the envelopes to a settle-down station. The settle-down station includes a guide channel which has a lower edge thereof parallel with the passageway set at an elevation at which the edge of the envelope is designed to pass into the first burner section. As the envelope is released at the settle-down station, the lower edge thereof will contact the platform of the channel thus assuring the proper orientation and elevation of the first edge of the envelope to be passed into the first burner assembly. Thereafter. a paddel wheel conveyor belt, which operates in time sequence with the pick-up mechanism. will move the envelope into the opposed conveyor belts for passage into the first burner assem bly. Similar settle-down stations are also employed for feeding the envelopes into the second and third burner assemblies.  
  Other objects and advantages of the present invention will become apparent from the detailed description thereof taken in conjunction with the drawings.  
 DESCRIPTION OF DRAWINGS FIG. I, is a diagrammatic view ofthe envelope opening apparatus and method of the present invention;  
  FIG. 2. is a sectional view of the radiation and heated gas burner assembly of one embodiment ofthe present invention;  
  FIG. 3, is a sectional view of a second embodiment of burner employing radiation and reflective means;  
  FIG. 4. is a sectional view of a third embodiment of burner employing radiation and optical focusing means:  
  FIG. 5., is a plan view of the settle-down station ofthe present invention;  
  FIG. 6. is a sectional view ofa fourth embodiment of radiation burner employing direct heating. and  
  FIG. 7. is a diagrammatical view of a fifth embodi ment of burner employing laser energy.  
 DETAILED DESCRIPTION OF INVENTION The overall concept of the apparatus and method of the present invention may be seen from the diagrammatic illustration thereof shown in FIG. 1. The envelopes to be opened are loaded onto the loading conveyor I0. A pick-up mechanism 11 removes the envelopes from the loading conveyor and passes them to a settle-down station 9. The settle-down station 9 properly orientates the envelopes in respect to the first burner assembly 14. The settle-down station 9 operates in sequence with the pick-up mechanism 11 and moves the envelopes into the opposed belts l2 and 13 in sequence with the next deliverly of an envelope to the settle-down station by the pick-up mechanism 11.  
  The loading conveyor and pickup mechanism 11 are so arranged that the envelopes are fed into the opposed belts standing on one of their two shorter edges. As the belts move the envelopes through the burner 14, the edges thereof are carbonized and weakened in accordance with the particular embodiments of burner to be later described.  
  The weakened envelope is then moved, by conveyor belts l2 and I3, into a first flip-over and settle-down mechanism IS. The flip-over mechanism 15 is actuated by a photoelectric device upon the presence of the envelope and rotates the envelope through 90 degrees. Upon the envelope being rotated through 90 degrees. the next adjacent elongate edge of the envelope passes through a second pair of opposed conveyor belts l6 and I7. The conveyor belts l6 and I7 carry the envelope through a double set of burner assemblies 18 and 19. The elongated edges are then carbonized in the same manner as the first edge in the burner assembly 14.  
  Two burners l8 and 19 are required for the elongated edge to maintain the flow rate through these burners without interference with the following envelopes inasmuch as the elongated edges are approximately the length of the shorter edges thereof. The speed of belts l6 and 17 are adjusted accordingly.  
  On the envelope completing its passage of the double burner assembly 18 and 19. it is then passed into a second flip-over and settle-down mechanism 20 which is identical to the first flip-over and settle-down mechanism 15. In the second flip-over 20, the envelopes are again rotated and passed into a third burner assembly 21. At the completion ofthe second flip-over. the next adjacent shorter edge of the envelope is presented to the third burner assembly. The envelope is carried through the third burner assembly by a third set of opposed belts 22 and 23 and delivered to a third flip-over mechanism 24.  
  The third flip-over mechanism 24 operates in an identical manner to that of the first and second flipover mechanisms I6 and 21 respectively. Upon the envelope passing the third flip-over mechanism, its uncarbonized edge is then turned down and the envelope feed into a turn-down mechanism 25. The turn-down mechanism grasps the envelope and lowers it to a con veyor 26. The envelope, at this time. is in such a disposition that its unburned edge is trailing on the conveyor 26. The envelopes, so arranged. are then passed into differential opener 27. The differential opener 27 in cludes a belt upon which the envelopes are carried through the opener and. also. a roller running in engagement with the conveyor belts. The brake assembly on the conveyor belts work in conjunction with a photoelectric cell to sense the presence of the envelope. At a predetermined time in the sequence, the photoelectric cell applies the brake for a predetermined time and generates a shearing force on the three weakened edges of the envelope. The shearing force results in the weakened edges being broken away and one side of the envelope scrubbed back or opened revealing the contents. The opened envelopes are then passed onto an off bearing conveyor 29. The envelopes are permitted to move down the off bearing conveyor 29 past a number of stations at which operators are positioned to select and sort the opened mail.  
  The present invention represents further modifications and improvements in the burner assembly and conveying mechanism of co-pending application Ser. No. 817,6l9 filed Apr. 16, I969. Accordingly, it is not felt necessary for the present invention to enter into a detailed disclosure of the details of the loading conveyor, pick-up mechanism. flip-overs, turn-down mechanism, conveyor, differential opener and off bearing conveyor, all of which are fully disclosed in the prior filed co-pending application.  
  One embodiment of the improved burner assembly of the present invention is shown in FIG. 2. The burner assembly includes a metalic box like housing 30. The upper central portion of the housing 30 includes a passageway 31 therein which extends for the length of the housing 30. Insulation 32 completely surrounds the housing 30 to further define the passageway 31.  
  Conveyor belts l2 and 13, which transport the envelope 33 through the burner assembly, pass in contact or substantially in contact with the upper surface of the insulation 32 during their passage along the passageway 31. The belts, disposed in this manner, serve to seal off the passageway 31 along the upper edges thereof, leaving only the entering and exit ends of the passageway opened.  
  Heater elements 34 and 35 are disposed in the housing 31 and on the opposite wall thereof from the edge 36 of the envelope to be carbonized. The heat output of the heaters 34 and will heat the passageway 31 to a temperature at which the passageway will radiate heat energy.  
  The radiated energy within the passageway 31 will both heat the air within the passageway and focus upon and carbonize the edge of the envelope in this manner. the combined effects of both heated air and radiation are had. The air within the passageway may be static air and heated to within the range of I00 to 850 degrees Fahrenheit.  
  A second embodiment of the burner assembly of the present invention may be seen in FIG. 3. In this embodiment, the principle heating is accomplished by means of radiation. The burner assembly includes a housing 37 which is surrounded by suitable insulation 38. The conveyor belts l2 and 13 operate in conjunction with this embodiment in a manner similar to that of the embodiment of FIG. 2 to define a passageway 39 through which the envelope will pass. The passageway 39, as in the embodiment FIG. 2, will be opened only at either end thereof.  
  A radiant heat generator 40, which may be of any suitable type i.ev gases discharge type or resistence type. is disposed in the lower portion of the housing 37.  
 A plurality of reflectors 41 are disposed around the periphery of the housing and so inclined and formed such that the substantial part of the radiant energy generator will be directed and focused against the lower edge of the envelope 33 to be carbonized.  
  A third modification of burner is shown in FIG. 4. In this modification. the radiant energy from the radiation generator 40 is focused optically and directed against the lower edge of the envelope 33 by means of a lens 42.  
  A fourth embodiment of burner assembly of the present invention is shown in FIG. 6. The embodiment of FIG. 6 employes a small elongate channel member 55 which operates in conjunction with its surrounding thermal insulation material 54 and conveyor belts l2 and 13 to form a passageway 57 much in the manner of that in the embodiment ofFlG. 2. A heating element 56 is disposed in the bottom portion of the channel 55 and serves to emit radiant energy within the passageway 57 to that sufficient to carbonize the lower edge 36 of the envelope. The heater 56 is designed to run for at least a part of the length of the passageway 57.  
  A fifth embodiment of burner assembly. in accordance with the present invention, is shown diagrammatically in FIG. 7. In this embodiment, a laser gun 57 and light source 58 for pulsing the gun are employed to direct a laser beam against the lower edge 36 of the envelope 33 to effect the carbonizing and weakening of the envelope. The laser gun and light source are enclosed within a housing 60 which is also enclosed within a suitable insulating surrounding 59. The envelope 33 is carried through the path of the laser beam by means of conveyor belt 12 and 13 in the manner described in conjunction with the previous embodiments. The laser beam may operate to one side of the edge 36 of the envelope or it may be disposed directly beneath the edge of the envelope so as to strike the sharp edge thereof. It is also anticipated that more than one laser beam may be employed and the beams may be directed against opposite sides of the envelope.  
  The burner assemblies of FIG. 2-4 and 6-7 have many advantages. The required heat input and heat-up time for both embodiments is substantially reduced over that ofthe hot air principle disclosed in the earlier referred to co-pending application. Additionally, as respects the radiant energy burners. the focusing of the radiant energy provides greater control and direction against the portions of the envelope to be carbonized. The embodiments of FIG. 2-4 and 6-7 further have the advantages of simplicity and compactness in that fans and air passageways are not required.  
  The settle-down station of the present invention is shown in FIG. 5. A vacuum pick-up arm 42 in the piclo up mechanism II removes an envelope 43 from the loading conveyor 10 and deposits the envelope within a guide channel 45. An envelope 46 is shown in delivered position in the guide channel 45. and an envelope 53 is shown after passage of the settledown station. The guide channel 45 includes opposed wall portions 47 and 48 and a bottom platform portion 49. The pick up mechanism 42 will move the envelope 46 between the side portions 47 and 48 and release the envelope. Upon the envelopes release. the envelope will drop. by gravity, into contact with the platform 49.  
  The upper surface of the platform 49 is disposed parallel to the passageway of the first burner section and at the proper elevation at which the edge of the envelope is to pass through the burner section. In this manner. as the envelope drops into contact with the platform 49, its first edge to be carbonized will be properly orientated and set at the right elevation for passage into the first burner section.  
  A paddle wheel conveyor 40 is disposed adjacent the sidewall 48 of the guide way 45. The conveyor 40 includes a flexible belt 51 which has a plurality of tabs 52 disposed on the outer circumference of the belt.  
  The belt 50 is driven in the direction of the arrow in sequence with the operation of the pick-up arm 42 in a manner such that one ofthe tabs 52 will move the envelope 46 into the conveyor belts l2 and 13 in advance of the next delivery ofthe next following envelope. The envelope 46, as it is passed into theconveyor belts l2 and 13, will thus be properly orientated and at the proper elevation for passage into the burner assembly.  
  Settle-down stations as shown in FIG. 5 are also employed in advance of the second and third burners. The settle-down stations are combined with the first and second flip-over and are fed by these flip-overs. The settle-down stations, in turn, feed the envelopes to the conveyor belts in the second and third burners.  
  The foregoing invention has been described in respect to the particular embodiments thereof shown in the drawings. However. no limitation is thereby intended on the scope of the invention but, instead, the scope thereof is to be interpreted in view of the appended claims.  
 We claim:  
  I. Apparatus adapted to weaken an edge of an envelope for the subsequent opening thereof comprising:  
 a passageway,  
 means for heating air within the passageway to a temperature suitable for carbonizing an envelope edge, means for generating radiant heat. and  
 a conveyor supported to move an edge of the envelope to be carbonized through the passageway without contacting the passageway in contact with both the heated air and radiant energy.  
  2. The method of weakening edges of an envelope to facilitate easy opening thereof including the steps of:  
  7 moving the envelope&#39;through static air within a passageway. heating the static air within the passageway to a temperature suitable to carbonize and weaken the edge. and directing radiant heat against the edge of the envelope to further aid in carbonizing the edge. 3. Apparatus adapted to weaken the edge of an envelope for subsequent opening thereof comprising:  
 a passageway. conveyor means for supporting and moving an edge of an envelope to be opened through the passageway. and radiant heat generating means within said passageway for directing radiant heat energy against the edge of the envelope to carbonize and weaken the edge of the envelope. 4. The method of weakening the edges of an envc&#39; lope to facilitate opening thereof including the steps of: moving the envelope through a fixed path with an edge thereof exposed unprotected. and generating radiant energy at a position spaced from the edge of the envelope and directing the radiant heat energy against the edge ofthe envelope to carbonize the edge of the envelope. 5. The method of opening envelopes comprising the steps of:  
 generating radiant heat within a predetermined zone. conveying an exposed and unprotected edge portion of at least one side of the envelope through the zone of radiant heat at a point spaced from the radiant heat to carbonize and weaken the edge. and separating the envelope at the weakened edge to expose the contents thereof. 6. Apparatus for destroying the edges of envelopes comprising:  
 a conduit. a source of radiant energy. means for delivering the radiant energy to the conduit,  
 a passageway through said conduit.  
 a conveyor disposed adjacent said passageway and adapted to convey at least one edge of the envelope through said passageway with the edge portion thereof in contact with the radiant energy within said passageway whereby the edge of the envelope will be carbonized and destroyed preparatory to opening thereof.  
 7. Apparatus for preparing the edges of an envelope for opening of the envelope comprising:  
 a conveyor for gripping an envelope and moving the envelope through a predetermined fixed path. said conveyor leaving exposed at least one edge of said envelope for treatment,  
 a source of radiant energy spaced from the edge of the envelope. and  
 means disposed adjacent said conveyor and in alignment with the edge of the envelope for directing the radiant energy against the edge thereof in its passage through said fixed path to carbonize and weaken the edge.  
 8. Apparatus for preparing the edges of an envelope for opening comprising:  
 a passageway,  
 a source of radiant energy in communication with said passageway of heat value sufficient to carbonize paper. and  
 a conveyor for gripping the envelopes to be opened with at least one edge thereof exposed for treatment and adapted to move said edge of said envelope through said passageway spaced from and out of contact with any portion of the passageway and with said edge spaced from said source of radiant energy but in contact with said radiant energy while maintaining the remainder of the envelope below carbonizing temperatures whereby the edges of the envelope will be carbonized and destroyed in their passage of said passageway.