Patent Publication Number: US-3876317-A

Title: Latch mechanism

Description:
United States Patent [1 1 u 11 3,876,317 Jordon Apr. 8, 1975 I LATCH MECHANISM 629.446 7/1219; James 4 292/244 1 7 2 2 751 Inventor: William E. Jordon, Penfield. N.Y. 9 I244 [73} Assignee: Xerox Corporation. Stam Primur Eraminen-Werner H. Schroeder Conn. Ans-mun! E.rumiowr-Conrad L. Berman [22] Filed: Sept. 24, 1973 1211 Appl. No.: 400,448 1571 ABSTRACT A reproduction machine employing a heated roll fuser [52&#39; U s ms/6T 79/45? for fixing the transferred developed image on a sup &#34;aikg&#39;fl i i fi gi port material. the fuscr back-up roll being held against [5]] Int 0 i 5 the driven. heated roll by a latch mechanism employ &#39;58] i 740 744 ing a rotatable bolbhandle, rotation of the bolt causmapm v6 31.0 h 91- ing the back-up roll to unlatch and allow the roll to be L 3 {pp f 5 5 pivoted out of contact with the heated fuser roll by a i i 5 7 2 lifting force on the bolt handle to provide single handed disengagement and movement of the roll to [56&#39; Reerences cued enable the machine operator to clear jams in the fuser &#39;th the fre h d.  
 UNITED STATES PATENTS e an 437.536 s lxuu Bartlett 403/330 5 Claims 6 Drawing Figures LATCH MECHANISM BACKGROUND OF THE INVENTION In recent years, xerographic reproduction machines which were initially introduced as devices for making casual copies of a document. have been developed to a point whereat they may be utilized for high speed printing operations capable of producing thousands of copies per hour. As the speed of the machines has increased, so also has the problem of paper jams increased. In a high speed machine it becomes necessary to provide means for rapidly and simply clearing the paper jams to allow maximum utilization of the ma chine. It has been the practice to provide means to unlock various transports and other elements of the reproduction machine to allow them to be moved out of operative position and locked into an inoperative position to enable the machine operator to remove copy sheets jammed therein. However, the latching mechanisms which have heretofore been used ordinarily require the operator to utilize both hands for unlatching the mechanism and moving it to the inoperative posi tion, thereafter removing the jammed copy sheets, and again utilize both hands to move the mechanism back into the operative position and lock it in place. In order to allow maximum utilization of the reproduction machine, it is desirable to provide a simple yet positive latching mechanism which can be operated by one hand to allow the operator to unlatch and move the mechanism in one simple operation out of operative position and enable the operator to use his other hand to remove the copy sheet and subsequently relatch the mechanism in operative position.  
 SUMMARY OF THE INVENTION This invention relates to a latch mechanism for releasably securing a first member to a second member including a rotatable shaft secured to the first member, the end of the shaft being formed at an angle relative to the axis of the shaft to provide an inclined surface thereon adapted for engagement with a resilient striker plate secured to the second member, the striker plate having an opening therein adapted for receiving the shaft and retaining the shaft therein, engagement of the inclined surface ofthe shaft with the plate causing relative movement therebetween in a direction substantially parallel to the axis of the shaft, the shaft being adapted for rotation to a first position for engagement of the inclined surface thereof with the striker plate for engagement of the shaft in the opening in the plate and for rotation to a second position wherein the inclined surface is displaced substantially 180 from the first position for disengaging the shaft from the opening in the striker plate. The shaft is provided with a handgrip thereon to enable an operator to grasp and twist the shaft to disengage the first member from the second member and move the first member away from the second member by a simple one-handed twist-lift movement of the rotatable shaft.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic sectional view of a high speed reproduction machine employing the improved latch of the present invention;  
  FIG. 2 is an isometric view of a portion of the fuser mechanism utilized in the reproduction machine of FIG. I illustrating the simplified latch of the present invention;  
  FIG. 3 is a partial sectional view illustrating the relationship between the latch bolt and the latch striker plate prior to engagement of the bolt in the striker plate;  
  FIG. 4 is a partial sectional view of the latch showing the bolt and striker plate upon initial contact of the striker plate by the bolt;  
  FIG. 5 is a partial sectional view of the latch illustrating the position of the bolt in striker plate when the bolt is secured in the striker plate; and  
  FIG. 6 is a partial sectional view of the latch mechanism showing the bolt rotated preparatory to disengaging the bolt from the striker plate.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT For a general understanding of an electrostatic processing system in which the invention may be incorporated, reference is had to FIG. 1 in which various components ofa system are schematically illustrated. As in most electrostatic systems such as a xerographic machine, a light image of an original to be reproduced is projected onto the sensitized surface of a xerographic plate to form an electrostatic latent image thereon. Thereafter, the latent image is developed with an oppo sitely charged powder to form a xerographic powder image corresponding to the latent image on the plate surface. The powder image is then electrostatically transferred to a support surface to which it may be fixed by a fusing device whereby the powder image is caused to permanently adhere to the support surface.  
  The electrostatically attractable developing material commonly used in electrostatic reproduction systems comprises a pigmented resinous powder referred to here as toner and a carrier&#34; of larger granular beads formed from a material removed in the triboelectric series from the toner so that a triboelectric charge is generated between the toner powder and the granular carrier. The carrier also provides mechanical control so that the toner can be readily handled and brought into contact with the exposed xerographic sur face. The toner is then attracted to the electrostatic latent image from the carrier to produce a visible powder image on an insulating surface.  
  In the illustrated machine, an original D to be copied is placed upon a transparent support platen P fixedly arranged in an illumination assembly generally indicated by the reference numeral 10. While upon the platen, an illumination system comprising two or more lamps L and reflectors is flash energized to direct light rays upon the original to produce image rays corresponding to the informational areas on the original. The image rays are projected by means of an optical system 1! to an exposure station A for exposing the photosensitive surface ofa moving xerographic plate in the form ofa flexible photoconductive belt 12. In moving in the direction indicated by the arrow, prior to reaching the exposure station A, that portion ofthe belt being exposed would have been uniformly charged by a corona device 13 indicated at a belt run extending between belt supporting rollers 14 and 15, the latter being the drive roller for the belt. The exposure station extends between the roller I4 and a third support roller 16. The belt run between these rollers is encompassed entirely by the exposure station for minimizing the space of the belt and its supporting rollers.  
  The Exposure of the belt to the light image discharges the photoconductive layer in the areas struck by light whereby there remains on the belt a latent electrostatic image in image configuration corresponding to the light image projected from the original on the support platen. As the belt surface continues its movement, the electrostatic image passes around the roller 16 to a developer station B located at a third run of the belt and in which there is positioned developing apparatus generally indicated by the reference numeral 17. The developer apparatus 17 comprises a plurality of brushes which carry developer to the adjacent surface of the upwardly moving inclined photoconductive belt 12 to provide development of the electrostatic image.  
  The developed electrostatic image is transported by the belt 12 to a transfer station C located at a point of tangency on the belt around the drive roller whereat a sheet of copy paper is moved at a speed in synchronism with the moving belt in order to accomplish trans fer of a properly registered developed image.  
  There is also provided a copy sheet supplying apparatus comprising a main paper feed supply 20 and an auxiliary paper feed supply 21. Each of the paper supplies is adapted to separate sheets from their respective supply stacks and to transport the sheets to a sheet registration station and eventually into contact with the developed image on the belt as the same is carried around the drive roller 15. A suitable timing control mechanism is operatively associated with each of the paper supply mechanisms 21, 22 and the flash illumination devices L, for producing an electrostatic latent image on the belt 12 to present a developed image at the transfer station C in timed sequence with the arrival of a sheet of paper, and is coordinated with the activation of other processing and control devices at the precise time that these elements are to function for their intended purpose.  
  After the developed image is transferred to a sheet of paper, it is stripped from the belt 12 and conveyed by conveying system 23 into a fuser apparatus generally indicated by reference numeral 24 wherein the devel oped and transferred xerographic powder image on a sheet material is affixed thereto. The finished copy is thereafter discharged from the apparatus by a conveyor 25 at a suitable point for collection externally of the ap paratus.  
  The fuser apparatus 24 comprises a driven, heated roller 26 and a freely rotatable roller 28 adapted for engagement with roller 26 to assure contact of the sheet material with the heated roller for affixing the image on the sheet material. The heated roller 26 is suitably mounted on a frame member 30 of the machine by means of bearings 32. Roller 28 is mounted in bearings 34 on a sub-frame 36 which in turn is pivotally mounted on frame 30 by pins 38 to enable roller 28 to be pivoted away from roller 26 for clearing paper jams or performing other operations on the rollers such as cleaning of the roll surfaces.  
  The subframe and the roller 28 mounted thereon is secured in operative position by a novel latch mechanism comprising a shaft or bolt 40 journaled for rotation in a depending portion 42 of sub-frame 36. Each end of bolt 40 is provided with an inclined surface 41 thereon adapted for engagement with resilient striker plates 44 secured to frame members 30 by suitable means such as rivets 46. The striker plate is provided with an opening 48 adapted for receiving the end of bolt 40 and retaining the shaft therein. While the preferred embodiment illustrates an opening formed by the displacement of a tab portion 50 from the plane of the striker plate 44, it should be understood that a circular opening could be provided therein if the inclined surface 41 is formed such that the inner portion thereof lies inside the inner surface of the striker plate.  
  The bolt 40 is provided with a handle grip 52 to enable the machine operator to easily rotate the shaft for reasons to be hereinafter explained.  
  Referring to FIGS. 3 through 6 wherein the operation of the latch mechanism is illustrated in a step-wise fashion, it can be seen from FIGS. 3 and 4 that movement of bolt 40 towards striker plate 44 causes the inclined surface 41 of bolt 40 to displace striker plate 44 until bolt 40 is in alignment with opening 48 at which time, as illustrated in FIG. 5, the striker plate is free to return to an unstressed position and retain bolt 40 therein. To disengage bolt 40 from striker plate 44, handle 52 is grasped by the machine operator and rotated l to the position illustrated in FIG. 6.  
  Rotation of bolt 40 causes the end thereof to force tab 50 and striker plate 44 attached thereto away from frame member 30 to disengage bolt 40 from plate 44 and allow sub-frame 36 and the roller 28 attached thereto to be pivoted away from roller 26.  
  It can be seen from the foregoing that the subframe may be unlatched and pivoted away from roller 26 by a simple one-handed twist-lift motion thereby allowing the operator to clear jammed papers in the fuser with his free hand and thereafter re-latch sub-frame 36.  
  If desirable, bolt 40 may be biased by suitable springs (not shown) toward the position illustrated in FIGS. 3 through 5 although in the illustrated embodiment, the angled tab 50 and surface 41 on bolt 40 have a tendency to force the shaft toward the desired angular orientation.  
  While the latch has been described in conjunction with the fuser assembly in a reproduction machine, it should be understood that the latch mechanism is also suitable for use with the transfer roller or various paper transports to provide rapid access to any portion of the paper path for clearing jams therein and enable the machine to be quickly put back on-line after a jam type malfunction.  
  While I have described a preferred embodiment of my invention, it should be understood that the invention is not limited thereto but may be otherwise embodied within the scope of the following claims.  
 What is claimed is:  
  l. A latch mechanism for releasably securing a first member to a second member comprising:  
 a rotatable shaft secured to said first member, the end of said shaft being formed at an angle relative to the axis of said shaft to provide an inclined surface thereon;  
 a striker plate secured to said second member, said plate having an opening therein adapted for receiving said shaft and retaining said shaft therein, engagement of the inclined surface of said shaft with said plate causing relative movement therebetween in a direction substantially parallel to the axis of said shaft, said shaft being adapted for rotation to a first position for engagement of the inclined surface thereof with said striker plate when said first member is moved toward said second member for engagement of said shaft in the opening in said plate and for substantially 180 rotation to a second position when said shaft is engaged in said opening to displace the inclined surface substantially l80 from said first position for subsequent disengage ment of said shaft from the opening in said striker plate by movement of said first member away from said second member.  
  2. A latch mechanism according to claim 1 wherein said striker plate is formed of a resilient material, movement of the inclined surface of said shaft in a di rection substantially parallel to the plane of said plate causing movement of said plate relative to said shaft in a direction substantially parallel to the axis of said shaft, alignment of said shaft with the opening in said striker plate allowing said plate to move toward said shaft to retain said shaft in said opening.  
  3. A latch mechanism according to claim 2 wherein said striker plate is provided with a tab thereon in alignment with the opening therein, said tab being disposed at an angle to the plane of said plate corresponding to the angle of the inclined surface on said shaft, engagement of said tab by said shaft causing said shaft to be rotatably urged toward the latching orientation.  
  4. A latch mechanism for releasably securing a first member to a second member comprising:  
 a rotatable shaft secured to said first member, the  
 end of said member having a surface thereon inclined at an angle relative to the shaft axis;  
 a striker plate secured to said second member, said plate having an opening therein adapted for receiving and retaining said shaft, engagement of the inclined surface of said shaft with said striker plate causing relative movement between said plate and said shaft in a direction parallel to the axis of said shaft, alignment of said shaft with the opening in said plate allowing relative movement between said plate and said shaft for engagement of said shaft in the opening of said plate, said shaft being rotated to position the inclined surface thereoftoward said second member when said first and second members are to be secured to each other, said shaft being rotated when in the latched position to oppo sitely orient said inclined surface to allow disengagement of said first and second members.  
  5. A latch mechanism for securing a first member to a second member including a rotatable shaft mounted on said first member, the ends of said shaft having a surface formed thereon at an angle relative to the axis of said shaft;  
 striker plates affixed to said second member for mating engagement with the ends of said shaft, engagement of said striker plates by the angled surfaces on the shaft causing said plates to be displaced outwardly, said plates having openings therein for receiving the ends of said shaft, alignment ofthe shaft with said openings allowing said plates to move in wardly to retain said shaft in said openings. said shaft being rotatable within said openings to orient the angled surfaces thereon to a position to force said plates outwardly and allow disengagement of said shaft from said plates.  
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