Abstract:
An assembly has a frame that defines at least one opening and a subsystem that is movable relative to the frame. At least one slide connects the subsystem to the frame such that the weight of the subsystem transmits a force to the slide. The slide includes at least one projection that extends through the at least one opening in the frame. At least one urging member biases the projection to at least partially counter the force transmitted to the slide by the weight of the subsystem. At least one docketing pin slides into at least one docking hole with minimal vertical load on the docking hole.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates to apparatus and methods for connecting a movable subsystem to a frame. 
     2. Description of Related Art 
     Many machines, such as imaging devices, copiers, fax machines and printers, for example, have subsystems that are movable relative to other components of the machine, such as a machine frame, for example. These subsystems may be moved for various reasons, for example, routine maintenance or to replace a dispensable material, such as paper, ink or toner, for example. In one example, the front panel of a copier may be opened and a subsystem, such as a fuser or paper drawer, may be slid out for maintenance or for reloading. These and other subsystems may be mounted on various types of sliding devices to allow them to be removed and replaced with an adequate amount of precision. 
     SUMMARY OF THE INVENTION 
     Machines that have slidable subsystems, i.e., subsystems that are slidable relative to other components of the machine, such as a machine frame, may, for example, have a rail or other type of member on which the subsystem slides (hereinafter “slide”) that includes a fixed portion mounted to a portion of the machine frame. In some cases, for example, subsystem location tolerance requirements and mounting rigidity are more stringent than can be provided by the slide(s) alone. This may occur for example, when the subsystem is mounted on a ball slide or other such slide having rolling elements. In this case, locating pins or other such similar devices may be added to the subsystem and communicate with the corresponding holes in the machine frame. When a subsystem, for example, a paper drawer or fuser on a copier, is slid back into the machine after maintenance, these locating pins can slide into their corresponding holes, thus locating the subsystem to the machine frame with high precision and stiffness. However, the locating pins do not have to be mounted to the subsystem and instead can be associated with other components, such as the slide or subassembly frame, for example. 
     These locating pins or other such devices, may tend to resist the motion of the slides when a subsystem is being docked or undocked, due to a lack of compliance and misalignment due to tolerance between the locating pins and their corresponding holes in the machine frame. In other words, the locating pins or other devices may contact i.e., rub against, for example, the surface(s) of the machine frame defining their corresponding holes, which after continuous or extended usage, may result in damage to the locating pins and/or machine frame, and/or may make it more difficult for an operator to slide the subassembly. 
     To prevent, minimize or reduce this problem, slide mount screws that mount the slide to both the locating pins and the subsystem may be tightened after the subsystem is docked to the machine, thereby temporarily realigning the slide. However, this is not a very fast assembly procedure and may be easily skipped or done incorrectly. However, the slide mount screws may ultimately become loose again, thereby requiring periodic maintenance. This lack of alignment may ultimately be manifested, for example, by the locating pins dropping due to the deformation/warping of the slide. The slides may become deformed/warped due to being subjected to the weight of the subsystem over time. However, the lack of alignment between the locating pins and their corresponding holes may be caused by other reasons. For example, other acting forces of various components of the apparatus may cause a lack of alignment such as gravity acting to distort the frame if supported on rough or uneven surfaces. 
     The above circumstances may eventually result in high loads being exerted on the surfaces of the machine frame that defines the holes by the location pins. These loads will increase the force necessary to open and close the subsystem and also increase wear on various features of the machine, such as the surfaces of the machine frame defining the holes. In particular, a large amount of wear and deformation may be experienced on the locating pins and the corresponding holes in the machine frame. This wear may reduce mounting precision and thereby be responsible for mislocation of the subsystem relative to the machine frame and other components, which in turn can create operational problems with the machine, such as producing paper jams and creating bad images in the case of an imaging device, for example. A lack of mounting precision can also cause other non-operational problems. 
     The problem of wear between the locating pins and the machine frame may be addressed by installing bushings or other such elements in the mounting pin holes of a machine frame. Thus, when the bushings are worn due to continuous contact with the locating pins, they may be replaced without having to replace the entire machine frame. Conversely, the locating pins may also be removably mounted on the subsystem, subsystem frame or slide, such that they may also be replaced periodically when they become worn. In addition, sleeves may be provided on the locating pins that may be replaced when sufficiently worn. While the use of bushings, removable locating pins and sleeves may temporarily address the problem, they still require periodic maintenance to ensure that the machine continues to function at an optimum level. 
     While the problems above have been described with reference to a machine having locating pins that are mounted in corresponding openings, the apparatus according to this invention is intended to be used with any other applicable currently known or later developed device having mechanically interlocking members of various forms or shapes for precisely locating moving elements. 
     This invention provides systems and methods for using one or more urging members to both retain and bias the fixed portion of a slide relative to a machine frame. In various exemplary embodiments of this invention the urging member may be a torsion spring that is mounted to a rear side of a machine frame, for example. A projection, for example a tongue, on an end portion of the slide protrudes through the machine frame and passes over one leg of the torsion spring. When the slide is fully inserted into the machine frame, a leg of the torsion spring rises into a notch in the tongue to retain it and prevent the slide from being pulled out of the machine frame. The torsion spring may exert an upward force on the slide until the slide hits a top portion of its corresponding opening in the machine frame. 
     In various exemplary embodiments of this invention the biasing force applied by each urging member may be equivalent to the gravity induced load the subsystem exerts on the portion of the slide where the urging member is located. For example, one quarter of the mass of the subsystem. However, any number of urging members may be used, thereby varying the necessary biasing force to be applied by each urging member. In addition, the biasing force of each urging member may be varied based on the total percentage of the weight of the subsystem to be countered by all of the urging members. Because the urging member is exerting a force upward as the subsystem closes, it tends to counter the weight of the subsystem. This causes the pin to hole force to be minimized thereby reducing the wear on the locating pins and corresponding holes, as well as the frictional force required to insert the locating pins into their corresponding holes in the machine frame. 
     While the problems above have been described with reference to a spring, such as a torsion spring, the apparatus according to this invention is intended to be used with any other applicable currently known or later developed urging member. 
     In various exemplary embodiments of this invention, minor side-to-side motion of the subsystem may be allowed by compliance of the slide. In other exemplary embodiments, additional side-to-side motion may be allowed for, by installing a plate on the machine frame that is free to slide in one or more directions on the machine frame itself. The slide is then mounted to the plate, thus relieving any horizontal forces that may be transmitted from the machine frame to the slide. In one exemplary embodiment of this invention one side of the subsystem has mounting pins and projections that mount directly in openings in the machine frame, thus, having very little horizontal float. The other slide incorporates a plate that rests on the cut edge of tabs bent out of the back of the machine frame. The projection or tongue is inserted through an opening in the plate. 
     In this embodiment, the slide has little horizontal float in the plate, but the plate is free to move side-to-side relative to the machine frame. The corresponding pins on this side of the subsystem fit into holes in the machine frame that are elongated in a horizontal direction, for example, allowing the pins to float horizontally in the machine frame. This feature fixes the slide in a vertical direction. In this way, the load capacity of the slide is not compromised by letting the axis of maximum section modulus move off of vertical. In addition, this feature reduces lateral forces on the slides and subsystem, thus preventing warping that may occur to the slides or the subsystems. 
     While the problems above have been described with reference to a plate mounted to a machine frame that allows for movement in one or more directions, the apparatus according to this invention is intended to be used with any other applicable currently known or later developed member that is capable of supporting an end of the slide while allowing for float in at least one direction. 
     In various exemplary embodiments an urging member, such as a torsion spring is mounted onto a tab or holding member located on either the sliding plate or the machine frame itself. A leg of the spring that supports the slide has a “z” or “u” bend on it and is passed through a vertical slot in the plate or machine frame. This “z” or bend performs at least three functions. First, it holds the spring near the machine frame or plate as the slide projection is pushed over it. Second, it limits the vertical motion of the spring before the slide projection is installed, and third, it provides a handle on the front side of the machine frame or plate to disengage the spring from the slide projection. This may be especially helpful when the device of this embodiment is being disassembled, i.e., the slide is being removed from the machine frame or plate. 
     In various exemplary embodiments of this invention it may be preferable that a slot or notch in the projection that is engaged by the spring be at a slight angle, such that the spring leg will enter the slot even if it is located, for example, a few millimeters away from the frame or plate. In this case, the spring leg would then move towards the backplate as it moves into the slot, thus reducing float in a direction normal to the machine frame or plate. In various exemplary embodiments of this invention, the required gap for accommodating the spring is relatively small due to the fact that the tolerances for the various subsystems used with the machine may also be small. However, in other exemplary embodiments where tolerances are not required to be small, this gap may be relatively large. 
     In various exemplary embodiments of this invention, a slide assembly, which may encompass one or more slides, may be interchangeably mounted on a machine frame or plate. In other words, the entire slide assembly may be flipped upside down and mounted in the machine frame. In addition, because each individual slide may be interchangeable, the total number of individual parts necessary to assemble a slide assembly may be reduced. 
     The systems and methods of this invention also allow for greater speed in the mounting of a subsystem in a machine. In one exemplary embodiment of this invention the urging member or spring may be easily twisted and snapped onto the tab on the backplate or machine frame. The slide may then be simply pushed through an opening in the machine frame or plate without further adjustments. Thus, no screws or other fasteners are necessary and important assembly sequences are also not required. 
     While the various exemplary embodiments of this invention are discussed above in the context of an imaging device, it should be appreciated that the devices and methods of this invention are intended for use in any applicable field of endeavor, such as vending machines, gaming machines, etc., for example. 
     These and other features and advantages of this invention are described in or apparent from the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, in which like elements are labeled with like numbers and in which. 
         FIG. 1  shows an exemplary embodiment of the subsystem slide retainer mounted to a machine frame according to this invention. 
         FIG. 2  is an exemplary embodiment of an upper slide with mounting pin and urging member and no horizontal float. 
         FIG. 3  is an exemplary embodiment of a lower slide with mounting pin, urging member and plate with horizontal float. 
         FIG. 4  shows a side view of the subsystem slide retainer of  FIG. 1 . 
         FIG. 5  illustrates an overhead view of the subsystem slide retainer of  FIG. 1 . 
         FIG. 6  illustrates an exemplary embodiment of a plate for use with a slide retainer of this invention. 
         FIGS. 7A and 7B  illustrate an exemplary embodiment of a locating pin according to this invention; and 
         FIGS. 8A and 8B  illustrate an exemplary embodiment of an urging member according to this invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     For convenience of explanation, exemplary embodiments of the invention are described below with reference to the figures in the context of an imaging device, such as a copier, fax machine printer or the like. However, as previously discussed, all exemplary embodiments of the invention are intended to be used in any applicable field of endeavor. 
       FIG. 1  shows an exemplary embodiment of a subsystem slide retainer that is mounted to a machine frame  10 . The machine frame  10  could be located in a device such as a fax machine, printer or copier, for example. Further, the machine frame  10  could be any type of member that is capable of supporting at least a portion of the weight of the subsystem  21  and subsystem frame  20 . As illustrated in  FIG. 1 , the machine frame  10  is illustrated from its back side, having most of the accessible portions of the machine located on its opposite side. In various exemplary embodiments of this invention the back side of the machine frame  10  may not be readily accessible without extensive disassembly of the machine itself. Upper slide  170  and lower slide  130  (not shown) are mounted to the front side of the machine frame  10 . A subsystem  21  having a subsystem frame  20  is mounted to both the upper slide and lower slide and is movable in the direction indicated by arrow  175 . It should be appreciated that in various other exemplary embodiments the subsystem  21  need not be mounted to the subsystem frame  20 , but instead may be mounted directly to at least one of the slides. 
     In various exemplary embodiments, the upper slide  170  and lower slide  130  may be ball slides or other such devices capable of translating both the subsystem  21  and subsystem frame  22 . In various exemplary embodiments, the subsystem  21  may be a fuser, print cartridge, paper drawer or any other subsystem that may be required to be movably mountable to a machine. In various exemplary embodiments of this invention the subsystem  21  may be movable via automation, such as a motor or other such device, and may be required to move continuously as part of an operation. In other exemplary embodiments, the subsystem  21  may only be required to be moved during periodic maintenance or during reloading, as in the case of a fuser or paper drawer. 
     Locating pins  50  and  60  may be mounted on movable slide portions  172  and  132  (not shown) or they may be mounted directly to the subsystem frame  20  or the subsystem  21 . When the subsystem is docked, locating pins  50  and  60  fit into corresponding holes  55  and  65 , respectively. In this embodiment, locating pins  50  and  60  move freely in and out of holes  55  and  65  when the subsystem  21  is docked and undocked. It should be appreciated that locating pins  50  and  60  may be any type of device usable to precisely locate moving members. For example, these pins may be various shaped male and female connectors that are capable of performing the same function as locating pins  50  and  60 . Further, the locating pins  50  and  60  need not be accommodated by holes in the machine frame, but instead may engage any type of fixed member on the machine frame  10 . 
     Upper slide tongue  40  and lower slide tongue  30  fix upper slide  170  and lower slide  130  to machine frame  10  via insertion into corresponding openings  45  and  35 . It should be appreciated that the tongues  40  and  30  may be any type of projection that is capable of transmitting a load from a slide to the machine frame or other member. The upper urging member  80  is mounted on the urging member holder  100 . In this embodiment, the urging member is a torsion spring. However, other types of urging members may be used without departing from the spirit and scope of the invention. Urging member  80  fits into slot  42  of upper slide tongue  40  and is bent to make contact with tab  110 . When urging member  80  is set in place it biases upper slide tongue  40  and upper slide  170  in an upward direction to counterbalance the weight of the subsystem  21 . The urging member  80  may be sized to counterbalance the weight of the subsystem  21  and subsystem frame  20  such that the upper slide tongue  40  exerts little or no force in either direction (up or down) to the opening  45 . Slots  45  and  35  are sized to allow vertical motion of the upper slide tongue  40 , but little lateral motion. The vertical play accommodates part tolerances and variations when pin  50  is in hole  55 . The small lateral clearance maintains the slide in a vertical orientation. Urging member retainer  150  accommodates a hook in the urging member  80  to prevent the urging member  80  from moving too far away from machine frame  10 . The urging member  80  also has a hook portion  83  (not shown) that extends to the front side of the machine frame  10 , the hook portion  83  may be pushed down from the front side of the machine frame to disengage upper slide tongue  40 , thus allowing for disassembly of the upper slide  170  from the machine frame  10 . It should be appreciated that the urging member  80  may be secured to the machine frame  10  in any manner that allows it to apply a biasing force to the slide. 
     When the urging member  80  is set in place and counterbalances upper slide tongue  40 , locating pin  50  may freely move in and out of hole  55  without creating excessive wear on either locating pin  50  or the hole  55 . Pin  50  has almost no vertical motion in hole  55 . In various exemplary embodiments, a bushing or other such device (not shown) may be inserted in hole  55  such that no wear will occur in the machine frame in the event of any accidental or unanticipated misalignment between the locating pin  50  and the hole  55 . Machine frame  10  has openings  25  and  15 . These openings perform various functions such as allowing limited access to the back side of the machine frame  10 , or mounting other connectors between the subsystem and frame. 
     Lower slide  130  has lower slide tongue  30  that fits through opening  35  in plate  140 . The plate  140  is mounted to the machine frame  10  via plate retainers  145 . These plate retainers are located in openings  147  in the machine frame  10  and allow for lateral movement (in the “horizontal” direction) of the plate  140  and thus of the lower slide  130  and lower slide tongue  30  relative to the machine frame  10 . It should be appreciated that plate  140  may also allow for movement in other directions and may be movably mounted to the machine frame  10  by various different means. Locating pin  60  located in an elongated hole  65  may likewise move laterally relative to the machine frame  10 . It should be appreciated that lateral or horizontal movement of the locating pin  60  may be permitted by various other means, for example, the locating pin  60  may be movably mounted to the subsystem  21 , subsystem frame  20  or the lower slide  130 . As discussed previously, this lateral movement is permitted in the lower slide  130  in order to accommodate location tolerance or variation between the two slides  130  and  170  while maintaining the vertical orientation of slide  130 , preventing compromise of its load capacity by letting the axis of maximum section modulus move off of vertical. 
     Urging member  80  is mounted on lower urging member holder  90 , connected to plate  140 . As such, urging member  80  is also capable of translating laterally relative to the machine frame  10 . In this embodiment, urging member  80  is illustrated as a torsion spring, having one end inserted in urging member retainer opening  160 . Urging member  80  has a hook portion  83  (not shown) that protrudes from the back side of plate  140 . This hook portion  83  prevents the urging member  80  from moving too far away from plate  140  and also allows for easy disassembly from the front side of machine frame  10 . The other end of urging member  80  is placed in contact with tab  120  to exert a biasing force on lower slide tongue  30  and lower slide  130 . As with the upper slide  170 , this biasing force counterbalances the weight of the subsystem  21  and subsystem frame  20  and ultimately counteracts the load in a downward direction on slide  130 . As such, locating pin  60  may freely slide in and out of hole  65  when subsystem  21  is docked or undocked. This reduces wear to the locating pin  60  and also to the upper and lower portions of hole  65 . The biasing force applied by urging members  80  also assists in preventing the warping of upper slide  170  and lower slide  130 . While the plate  140  is described above as accommodating the lower slide  130  it should be appreciated that the above arrangement could be applied to the upper slide  170  to accomplish a similar effect. 
     Urging member  80  exerts a biasing force on the lower slide tongue  30  at the point where the urging member is inserted into slot  32  on the lower portion of the tongue  30 . It should be appreciated that in various exemplary embodiments the urging member may exert a biasing force to the tongues  30  and  40  at any point to allow the biasing force to be transmitted to the slides. The lower slide tongue  30  has an elongated slot  32  to accommodate the diameter of the spring, the thickness of the machine frame  10  and the thickness of the plate  140 . As lower slide  130  and upper slide  170  are interchangeable, slot  32  of lower slide tongue  30  corresponds to slot  42  of upper slide tongue  40 . Slot  42  accommodates both the machine frame  10  and the urging member  80 . Conversely, slot  32  of lower slide tongue  30  corresponds to slot  43  of upper slide tongue  40 . 
       FIG. 2  is an exemplary embodiment of an upper slide having a locating pin  50  and urging member  80 . Urging member  80  is mounted on urging member retainer  100  which in turn is mounted on machine frame  10 . As shown in  FIG. 1 , upper slide  170  has upper slide tongue  40  inserted through machine frame  10 . Locating pin  50  is inserted in hole  55  and may be directly mounted to subsystem frame  20 . In this embodiment, the urging member  80  is illustrated as being connected in opening  150  and biased against tab  110 . As such, urging member  80  exerts a biasing force in an upward direction against upper slide tongue  40  and upper slide  170 , thus counterbalancing the weight of subsystem  21  and subsystem frame  20 . 
       FIG. 3  is an exemplary embodiment of lower slide  170  having locating pin  60 , urging member  80  and plate  140 . In this embodiment, both the plate  140  and the elongated hole  65  permit movement of the lower slide in a lateral direction (“horizontal” direction). This occurs because plate  140  is slidably mounted on machine frame  10  via plate retainers  145  formed in openings  147  of machine frame  10  and located at upper and lower portions of plate  140 . Locating pin  60  is permitted to move laterally via the elongated hole  65 . Thusly, the lower slide  130  and lower slide tongue  30  are permitted to move laterally, reducing lateral forces on the machine frame  10 , slide  130 , subsystem frame  20  and subsystem  21 . 
       FIG. 4  illustrates a side view of the exemplary embodiment of the subsystem slide retainer of  FIG. 1 . In this figure, subsystem  21  and subsystem frame  20  are illustrated in the docked position with locating pin  50  and locating pin  60  protruding through their respective holes  55  and  65  in machine frame  10 . The upper urging member holder  100  carries the upper urging member  80 , which is illustrated exerting a biasing force against tab  110 , thus biasing upper slide tongue  40  in a vertical direction. Upper slide  170  has a fixed portion  171  and a movable portion  172 . It should be appreciated that the slides  130  and  170  may have any number of moving portions or may consist of a single fixed portion that allows the subsystem frame  20  or subsystem  21  to translate relative to the machine frame  10 . In addition the slides  130  and  170  may incorporate any type of ball bearing or rolling type device. 
     The movable portion  172  is attached to the subsystem frame  20  which in turn is attached to the subsystem  21 . As stated previously the slides  130  and  170  may be mounted directly to the subsystem  21 . In this exemplary embodiment, the movable slide portion  172  may move relative to the fixed portion  171  via ball bearings or other such similar devices which reduce or eliminate friction or resistance between moving members. Lower slide  130  also has a fixed slide portion  131  that is fixed to the machine frame  10  and a movable slide portion (not shown) that is fixed to the subsystem frame  20  and ultimately subsystem  21 . Lower slide retainer  30  has slots  33  and  32  formed on lower slide tongue  30 . It should be appreciated that slots  33  and  32  may be located at various portions of the tongue  30 . In this embodiment the location of the slot  32  accommodates both plate  140  and machine frame  10  and also engages urging member  80 . 
       FIG. 5  is an overhead view of the exemplary embodiment of the subsystem slide retainer of  FIG. 1 . Subsystem frame  20  is illustrated in the docked position having locating pins  50  and  60  protruding through their respective holes  55  and  65  in machine frame  10 . Upper slide retainer  40  and lower slide retainer  30  are illustrated in place mounted to machine frame  10 . Urging member  80  is mounted on the upper urging member holder  100  and is illustrated in place exerting a biasing force in the vertical direction on upper slide retainer  40 . In this embodiment, locating pin  50  is illustrated as being fixed to locating pin frame  51  and locating pin  60  is illustrated as being fixed to locating pin frame  61 . Frames  51  and  61  are in turn fixed to movable slide portion  132  and movable slide portion  172  of lower slide  130  and upper slide  170 , respectively. 
       FIG. 6  is an exemplary embodiment of a plate for use with a slide of this invention. Plate  140  may be mountable on a machine frame  10  to allow lateral movement of a lower slide  130 . Plate  140  may also be used in other exemplary embodiments of this invention to allow lateral movement of an upper slide  170 . Plate  140  has an urging member holder  90  and a spring tab  120  for accommodating an urging member  80 . The opening  35  accommodates a slide projection such as a tongue  30  to allow vertical motion of the slide in machine frame  10 , but not to allow lateral motion, thus, keeping the slide in a vertical orientation. Urging member retainer opening  160  accommodates one end of an urging member, such as a torsion spring. Plates  140 , slide  30  and urging member  80  all move together laterally relative to machine frame  10 . 
       FIGS. 7A and 7B  are exemplary embodiments of a locating pin  50  having a locating pin frame  51  according to this invention. Locating pin  50  is fixed to locating pin frame  51  which may then be fixed to the movable portion of a slide via locating pin frame fasteners  52 . As stated previously, locating pin  50  and locating pin frame  51  may be fixed to either the movable portion of a slide, a subsystem frame or the subsystem itself. In various exemplary embodiments the locating pins may be movably fixed to a slide, subsystem frame, or subsystem to allow movement in at least one direction. 
       FIGS. 8A and 8B  are exemplary embodiments of an urging member  80  according to this invention. In this embodiment, urging member  80  is a torsion spring having leg  81  and leg  82 . Leg  82  has a hook portion  83  for accommodating the urging member retainer opening of either a plate  140  or a machine frame  10 .  FIG. 8B  illustrates urging member  80  in the set position with leg  81  bent at an approximate 90° angle to leg  82 . While  FIG. 8B  illustrates leg  81  bent at an approximate 90° angle, it should be appreciated that leg  81  may be bent to any angle in order to produce the desired biasing force on the slide and slide tongue. In addition, while the exemplary embodiments illustrated show a torsion spring, it should be appreciated that any type of urging member may be used to produce the desired effect in both the slide and slide tongue. 
     While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.