Abstract:
A locking mechanism selectively prevents rotational movement of a handle relative to a frame. The locking mechanism includes a fork member having first and second ends and pivotally attached to the frame member at a pivot located between the first and second ends; a first locking device located at the first end of the fork member; a second locking device located on the handle and engaging the first locking device on the first end of the fork member for preventing rotational movement of the handle; an elastic member for biasing the first and second locking devices into engagement; and an attachment mechanism located at the second end of the fork member. A tension force on the attachment mechanism pivots the fork member about the pivot member to disengage the first and second locking devices and allow the handle to rotate relative to the frame.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to a latch mechanism used in manually moving and locking various objects. 
     2. Description of Related Art 
     In an image forming apparatus, a user often needs to gain access to the various components within the image forming apparatus for repairing, replacing, cleaning, or other service related matters. Thus, image forming apparatus are preferably constructed in a modular configuration in which components are latched into position but are capable of being unlatched for access to the components. 
     SUMMARY OF THE INVENTION 
     The present invention describes a latch mechanism which may be used wherever a large motion and large force is required in a small area by use of manual power. However, the latch mechanism will be described as applied to just one possible structure having heavy components which need to be moved manually, i.e. components of an image forming apparatus. Also, the latch mechanism allows the components being secured to be unlocked and separated so that a user may access the components and the parts in between and inside each component. 
     The latch mechanism in one possible configuration comprises a first member, a second member pivotably connected to the first member, and a handle connected to the second member. A latch mechanism selectively maintains a first component in a fixed position relative to a second component. The latch mechanism include a first member for selective attachment to the first component; and a second member for selective attachment to a second component and pivotally attached to the first member. The first and second members assume a locked position when the first and second members are substantially aligned and assume an unlocked position when the first and second members are traverse to each other. A handle is pivotally connected to the second member. A link member is pivotally connected at one end to the second member and pivotally connected at an opposite end to the handle. The link member assumes a first position when the handle is moved to a corresponding first handle position to have the link member positioned overcenter with respect the first and second members to brace the first and second members in a locked position. The link member also assumes a second position when the handle is moved to a corresponding second handle position to move the link member traverse or undercenter to the second member to allow the first and second members to pivot relative to each other. The link member maintains the first and second members in the locked position until the handle is moved from the first handle position to the second handle position. A link member, which is attached to the second member and the handle, aids in locking the two members and reducing the pivotal movement between the two members. Furthermore, a ball joint is attached to one end of the first member and a bracket is attached to one end of the second member. The ball joint allows the latch mechanism to pivot along the X axis, and the bracket allows the link mechanism to pivot along the X and Y axes. A spring arrangement may also be added which pulls the link member toward a locked position. 
     Furthermore, in an image forming apparatus, if a user moves the pre-fuser transport into proper position before disengaging or re-engaging the xerographic towers and other components, there is a chance that this could cause damage to the prefuser transport. Therefore, a locking mechanism has been designed to require movement of the pre-fuser transport before unlatching other components such as the xerographic towers. 
     This invention provides a latch mechanism which may be used wherever a large motion and a large force is required in a small area by manual power. 
     This invention separately provides a latch mechanism which locks one or more components together securely. 
     This invention separately provides a latch mechanism which allows the device to unlock and lock components very quickly. 
     This invention separately provides a lock mechanism which reduces the likelihood of the prefuser transport and the xerographic towers from colliding due to user&#39;s failing to follow proper procedures. 
     This invention separately provides a lock mechanism which may be cheaply made and may be implemented in an image forming apparatus. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention will be described in relation to the following drawings, in which reference numerals refer to like elements, and wherein: 
     FIG. 1 is a top view of the image forming apparatus wherein the modular components and the latch mechanism are in a locked position. 
     FIG. 2 is a front view of the image forming apparatus wherein the modular components and the latch mechanism are in a locked position. 
     FIG. 3 is a right view of the image forming apparatus wherein the modular components and the latch mechanism are in a locked position. 
     FIG. 4 is a top view of the image forming apparatus wherein the modular components and the latch mechanism are in a full open position. 
     FIG. 5 is a front view of the image forming apparatus wherein the modular components and the latch mechanism are in a full open position. 
     FIG. 6 is a perspective view of the latch mechanism. 
     FIG. 7 is a top view of the latch mechanism in a full closed position. 
     FIG. 8 is a top view of the latch mechanism in a semi-open position with the first handle in a locked position and the second handle in an open position. 
     FIG. 9 is a top view of the latch mechanism in a full open position with the first handle and the second handle in an open position. 
     FIG. 10 is a top view of the locking mechanism. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1,  2  and  3  show the top, front and right view, respectively, of an image forming apparatus  100 , conventionally having modular sections, in a locked position by a latch mechanism  140 . It should be appreciated that the present invention may be used in various exemplary embodiments having various configurations, however, an explanation will be given with respect to one of many exemplary embodiments as shown in the figures discussed below. 
     As shown in the exemplary embodiment in FIGS. 1,  2  and  3 , the image forming apparatus  100  is conventionally configured in modular sections having a left xerographic tower  114 , a photoreceptor  118  and a right xerographic tower  122 . Conventionally, a recording medium enters the image forming apparatus  100  and moves from the left xerographic tower  114  to the photoreceptor  118  and is finally received by the right xerographic tower  122 . Each modular component ( 114 ,  118  and  122 ) contains various components which assist in forming the image on a recording medium. 
     When a user wishes to get access within the image forming apparatus  100  shown in FIGS. 1-3, the modular components must be separated, as shown in FIGS. 4 and 5, so that the user can access the individual components within the image forming apparatus to replace, clean, fix or to perform other service related matters. A device is necessary to enable the modular components to come apart, or be separated from one another, and then placed back into a locked position. Once the modular components are placed in a locked position, it is critical that these members stay in a stationary or fixed position relative to each other, and return to their original position. Therefore, the present invention, as illustrated in FIG. 6, shows one exemplary embodiment of a latch mechanism  140  which enables the modular components to come apart and become separated from one another and also enables the modular components to move back into a locked position. This advantage along with other advantages will become more apparent during the description of the latch mechanism  140  as described below. 
     FIG. 6 illustrates one exemplary embodiment of a latch mechanism  140 . The latch mechanism  140  has a first member  142  and a second member  144  which are connected by a pivotable attachment member  146  which in the exemplary embodiment is a screw type device, however the pivotable attachment member  146  may be a clamp, hinge or other like members. In the exemplary embodiment, the first member  142  is pivotably attached to the right xerographic tower  122 . The first member  142  has a ball joint  148  attached at one end, but in the exemplary embodiment the ball joint  148  is attached to the end which is attached to the right xerographic tower  122 . The ball joint  148  allows the first member  142  to pivot along the X axis. The other end of the first member  142  is connected to the second member  144  and is also able to pivot along the X axis due to the pivotable attachment member  146 . In the exemplary embodiment, the second member  144  has a slot portion  150  which is able to receive the first member  142 , and also allows the first member  142  to move along the X axis. 
     The second member  144  is pivotably connected at the other end to a U-shaped bracket  152 . The second member  144 , and accordingly the members attached to the second member, are able to rotate along the Y axis. The U-shaped bracket is attached to an outer frame  154  portion of the image forming apparatus  100 . The U-shaped bracket  152  is attached to the second member  144  in such a manner, so that the second member  144  is able to freely rotate along the Y axis. This feature allows the user to move the right xerographic tower  122  and a pre-fuser transport (not shown) in an upward direction to gain access to the two components. 
     The first member  142  has a first handle  160 . In the exemplary embodiment the first handle  160  extends upwards, along the Y-axis, and is attached to the first member  142 . The second member  144  has a second handle  162 . The second handle  162  extends along the X axis, and has curved shape. It should be appreciated that the present invention may operate with one handle, but in the exemplary embodiment the latch mechanism  140  has two handles  160  and  162 . The handles  160  and  162  allow the user to move the latch mechanism  140  which accordingly moves the modular components apart as shown in FIGS. 4 and 5. Furthermore, as shown in FIG. 6, the handles  160  and  162  have a gripping member  164  attached to the handles  160  and  162  to allow the user to grip the handles with greater ease. Also, a safety cover  165  may surround the latch mechanism  140  so that user&#39;s hand or other objects do not get caught within the components of the latch mechanism  140 . 
     The present invention also includes a first structure,  180  located on the second handle  162  and extending upwardly, and a second structure  182  located on the bracket  152  and also extending upwardly. An elastic spring  184  is connected between the first and second structures  180  and  182 , and applies a force which pulls the second handle clockwise toward a locked position. 
     To unlock the latch mechanism  140 , various steps and procedures may be performed, but a description will be given according to one possible configuration of the latch mechanism  140 . FIG. 7 shows the latch mechanism.  140  in a locked position with the first and second handles  160  and  162  in a locked position. FIG. 8 shows the latch mechanism in a semi-open position with the first handle  160  in a locked position and the second handle  162  moved to an unlocked position. FIG. 9 shows the latch mechanism  140  in an open position with the first handle  160  and the second handle  162  in an open position. 
     A detailed explanation of the operation of the latch mechanism  140  will be given with respect to one of the exemplary embodiments as illustrated in FIGS. 7-9. In FIG. 7, the latch mechanism  140  is in a locked position, therefore allowing almost no pivotable movement. In the locked position, the first and second members  142  and  144  are substantially aligned end to end, thus forming a brace for preventing movement of the modular components. The latch mechanism  140  is held in a locked by a link member  166  which is pivotally attached to the second handle  162  by a first pivoting member  170  and pivotally attached to the second member  144  by a second pivoting member  174 . The link member  166  is over center of the second member  144  when the latch mechanism  140  is in a locked position, thus maintaining the first and second members  142  and  144  in their end to end alignment. The end of the link member  166  opposite to the end connected to the second handle  162  is connected to a slotted portion  168  on the top portion or located within the slot portion  150  of the second member  144 . When the second handle  162  is rotated, the link member  166  is able to translate along the slotted portion  168  and also pivot with respect to the first pivoting member  170 . However, in the locked position, the pivoting member  174  is pressed against one end of the slotted portion  168 , thus bracing the link member  166  between the first pivoting member  170  and the second pivoting member  174 . When the link member  166  is in the locked position, the first and second members  142  and  144  can not pivot relative to each other because the handle  162 , and thus adjust the end  171  of the link member  166  maintains its position. Furthermore, the elastic spring  184  pulls the handle  162 , and thus adjusts the end of  171  of the link member  166  towards a locked position. 
     FIG. 8 shows the latch mechanism  140  in a semi-open position. In this position, the second handle  162  is pivoted outwards or counterclockwise. Because the link member  166  is pivotably connected to the second handle  162  by the first pivoting member  170 , the first end portion  171  of the link member  166  which is connected to the second handle  162  is pivoted in a clockwise direction. The second pivoting member  174  at the second end portion  176  is moved along the slot portion  168  towards the outer frame  154 . In this position, the first and second members  142  and  144  are no longer braced and are capable of pivotal movement relative to each other. 
     FIG. 9 shows the latch mechanism  140  in a full open position with both the handles  160  and  162  and the first and second members  142  and  144  in an open position. After the second handle  162  is rotated counterclockwise until the second handle  162  is no longer able to rotate, the user is able to pull the first handle  160  to rotate the first member  142  in a clockwise direction and the second member  144  in a counterclockwise direction. As shown in FIG. 9, the first and second members  142  and  144  form a V-shape when in the full open position. It should be appreciated that the latch mechanism  140  could be configured so that the latch mechanism  140  is able to open in the opposite direction. The outer frame  154  is a static structure, thus, when the first handle  160  is being pulled to an open position, the first member  142  pulls the right xerographic tower  122  toward the outer frame  154 . As shown in FIG. 4 when the latch mechanism  140  is in an open position, the modular components  114 ,  118  and  122  are pulled towards the outer frame and are separated from one another. 
     One of the advantages of the present invention is that the latch mechanism  140  allows the user to consume very little energy or power in order to separate the modular components or to lift the right xerographic tower along with the pre-fuser transport. The latch mechanism  140  is a manually operated two handle device and allows the user to quickly unlock and lock the modular components in less than 11 seconds. It should be noted that the latch mechanism  140  is not only useful in moving components in an image forming apparatus, but may be used wherever a large motion and large force is required in a small area with manual power. The second handle  162  is primarily used to move to link member  166  from a locked position to an unlocked position, and moves the modular components a small distance. The first handle&#39;s  160  primary purpose is to move the modular components to an unlocked position and separate the modular components from one another. 
     One of the problems with engaging and disengaging the xerographic towers  114  and  122  and the photoreceptor is that if the user does not follow proper procedural steps the xerographic towers  114  and  122  and the photoreceptor may collide and damage the components. Therefore, a locking mechanism  200  has been designed to solve this problem. The locking mechanism  200 , as shown in FIG. 10, generally comprises a locking fork  202 , a pivotably attachable member  204 , a pivoting pinion shaft key  206  and a spring  210 . 
     The locking mechanism  200  may be implemented in any type of rotary motion device to lock one or more members into a locked position. However, a description of the locking mechanism  200  will be given in relation to lock the latch mechanism  140 , which is in a locked position until the user has moved the pre-fuser transport. 
     The pivoting pinion shaft key  206  is attached to the second handle  162  of the latch mechanism  140 . The pivoting pinion shaft key  206  has a plurality of teeth  212  which surround the outer circumference of the pivoting pinion shaft key  206 . The locking fork  202  is pivotally attached to the second member  144  by the pivotably attachable member  204 . On one end of the locking fork  202  is a spring  210  and on the opposite end is an opening  214 . The end having the spring  210  also has a plurality of teeth  216  which are configured to engage and lock with the teeth  212  of the pivoting pinion shaft key  206 . The teeth  216  located on the fork  202  are designed to fully conform to the teeth  212  of the pivoting pinion shaft key  206  at any point of rotation of the fork  202  and pivoting pinion shaft key  206  assembly. 
     The end of the fork  202  opposite to that of the spring  210  has an opening  214  which is able to receive a cable  220 . The cable  220  connects the fork  202  to the pre-fuser transport (not shown). When the pre-fuser transport is moved into proper position, the cable  220  pulls the fork  202  in a clockwise direction, thus disengaging the teeth  212  of the pivoting pinion shaft key  206  from the teeth  216  of the fork  202 . Until the prefuser transport is moved, the teeth  216  of the fork  202  mesh against the teeth  212  of the pinion shaft key  206 , thus preventing pivotal movement of the handle  162 . However, once the prefuser transport is moved, the teeth  216  disengage from the teeth  212 . Therefore, the user is able to move the second handle  162  to open up the latch mechanism  140 . Unless the pre-fuser is moved into proper position, a user can not accidentally open the latch mechanism  140  and damage the prefuser transport. Furthermore, the spring  210  applies a locking force between the fork  202  and the pivoting pinion shaft key  206  producing a normally locked condition. 
     The pinion shaft key  206  is made from gear stock which is cheap and relatively durable. The locking member  200  allows a cheap locking device to be implemented to lock one or more devices in position. 
     While this invention has been described in conjunction with the exemplary embodiments outlined above, it is evident that may 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.