Abstract:
In an image printing device, such as a laser printer or ink jet printer, a coupling device for creating a coupling between a rotatable shaft and an interface component, such as a gear. The coupling device is an elongated modified c-shaped body having a portion for receiving the rotatable shaft, and includes integrated hinges that facilitate the coupling device to be spread apart and to receive and interface with the rotatable shaft. The integrated hinges function to compress between the rotatable shaft and interface component substantially inhibiting relative longitudinal movement and wherein a flat on the exterior of the rotatable shaft engages with a flat on the interior the interface component, to additionally inhibit relative rotational movement between the interface component and the shaft. The shaft further includes a plurality of ribs that extend from the rotatable shaft into the coupling device providing additional reduction in rotational movement between the shaft and the interface component. Retainers extending from the coupling device into the interface component provide another method of inhibiting relative rotational movement and/or provide a stop for press fit of the interface component onto the shaft.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     Not Applicable. 
     STATEMENT REGARDING FEDERALLY SPONSERED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     REFERENCE TO SEQUENTIAL LISTING, ETC. 
     Not Applicable. 
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a rotational coupling device, more specifically but not by way of limitation, a device that facilitates the operable coupling of a shaft with a component such as a gear or pulley disposed within a standard printer. 
     2. Description of the Related Art 
     Most printers have disposed therein a plurality of operably connected components such as gears, pulleys and rolls that function to perform a variety of activities. For instance, these components function to move printing media through the print path or to move the printhead in a desired motion. Conventional shafts are routinely operably coupled with at least one gear and/or pulley. These conventional shafts are substantially hollow having a consistent wall thickness to allow for minimal manufacturing times and warp minimization. These shafts routinely use areas known as flats, which are regions in the shaft that have at least two sides. The number of flats disposed on the circumference of the shaft can vary depending on the application. The amount of flats used on shafts can be as few as one or numerous different amounts of flats can be utilized. The flats are generally planar in shape to facilitate the coupling of a gear or pulley having a mateable shape to the shaft. 
     One problem with utilizing flats is that the flats cannot be disposed substantially along the entire length of the shaft as this type of configuration will interrupt the journal surface at the ends of the shaft. A discontinuous journal surface has been shown to create problems, such as uneven wear, as the shaft rotates and other negative effects such as untimely breakdown of any lubrication or bad acoustics. 
     Commonly, a shaft disposed within a conventional printer will be supported at the ends by bushings which facilitate rotational coupling with pulleys or rolls outside the bushings. The shafts further require a method of providing a rotational coupling to a gear in the middle of its span. As the shaft must be inserted through the pair of bushings from one direction, this forces the designer to make compromises. More specifically, the bushings are commonly manufactured to be different diameters. This increases the number of parts in the printer. Also, one journal can end up being too small a diameter for strength requirements, and the other too large for friction and cooling requirements. Indeed, the resulting multiple stepping of the shaft diameter can create a problem wherein the diameter is either too small or too large at any of the various rotational and non-rotational interfaces along the shaft. 
     Accordingly, there is a need for a device that can provide rotational coupling between a shaft and another component that can eliminate the need for or substantially reduce the number of steps required in the shaft. Furthermore, the device should substantially encircle the shaft and be able to be temporarily expanded in order to be traversed across the shaft and secured in the desired location on the shaft. The securing of the device to the shaft should be able to be accomplished without utilization of additional mechanical or chemical methods. Additionally, it is desired that subsequent to the expansion of the device and placement in its desired position along the shaft that the device returns to a shape and size such that the device compresses against the shaft substantially inhibiting any longitudinal movement. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the present invention, a device is provided to provide rotational coupling between a shaft and another component such as but not limited to a gear. The device comprises a semicircular shaped body having at least one hinge point wherein if outward pressure is applied to the ends of the semicircular shaped body the device expands so as to accommodate the reception of a shaft therethrough. Once the device has been traversed across the shaft to its desired position, the pressure is released from the ends of the semicircular shaped body thereby allowing the device to be biased towards its original state and slightly compress against the shaft. The shaft and device are then inserted through the desired component such as a gear wherein the gear is configured with a center hole to receive the device that is substantially encircling the shaft. The center hole of the gear is sized such that it causes compression on the device which compresses against the shaft such that any longitudinal or rotational movement of the device and gear is inhibited by the compression force of the device against the shaft. The device further includes at least one protruding surface that mateably connects with the gear or other component that has been mated thereto so as to further facilitate the securing of the gear to the apparatus. 
     To the accomplishment of the above and related objects the present invention may be embodied in the form illustrated in the accompanying drawings. Attention is called to the fact that the drawings are illustrative only. Variations are contemplated as being a part of the present invention, limited only by the scope of the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present invention may be had by reference to the following Detailed Description and appended claims when taken in conjunction with the accompanying Drawings wherein: 
         FIG. 1  shows a perspective view of an embodiment of the present invention; 
         FIG. 2  illustrates a perspective view of an exemplary laser jet printer in which an embodiment of the present invention could be employed; 
         FIG. 3  illustrates a perspective exploded view of an embodiment of the present invention in alignment with a shaft component of a printer; 
         FIG. 4  illustrates a perspective view of an embodiment of the present invention operably coupled with the shaft component of a printer; 
         FIG. 5  is a perspective exploded view of an embodiment of the present invention in alignment with a shaft component and a pick tire component of a printer. 
         FIG. 6  is a perspective exploded view of an embodiment of the present invention in alignment with a shaft component and a roll component of a printer. 
         FIG. 7  is a perspective exploded view of an embodiment of the present invention in alignment with a shaft component and a wheel component of a printer. 
         FIG. 8  is a perspective exploded view of an embodiment of the present invention in alignment with a shaft component and a pulley component of a printer. 
         FIG. 9  is a perspective exploded view of an embodiment of the present invention in alignment with a shaft component and a cam component of a printer. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings submitted herewith, wherein various elements depicted therein are not necessarily drawn to scale and wherein through the views and figures like elements are referenced with identical reference numerals, there is illustrated a coupling device  100  constructed according to the principles of the present invention. It is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Furthermore, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including”, “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected”, “coupled”, and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. 
     As shown in  FIGS. 1 and 3 , the coupling device  100  functions to provide a method of providing a rotational coupling between a shaft  205  with a mechanical component such as but not limited to a gear  200 . The exemplary shaft  205  and gear  200  illustrated herein are conventional components that are utilized in a printer  5  to facilitate such tasks performed by the printer  5  but not limited to, moving a media through a print path or placing an inkjet cartridge or printhead in a desired location at a specific time. The coupling device  100  comprises a body  10  that is a modified c-shape having a slot  15  that extends longitudinally through the body  10 . The body  10  is manufactured from a durable flexible material such as but not limited to polypropylene. The body  10  further includes a plurality of stops or retainers  20  that extend from the body  10  proximate one end  25 . The retainers  20  are integrally formed with the body and function to provide a mechanical method of limiting the distance that the coupling device  100  can be inserted into the gear  200 . The retainers  20  are shaped so as to be mateably connected with a notch  220  of the gear  200  with which the coupling device  100  is to be engaged as shown in  FIG. 3 . 
     The retainers  20  further function to reduce rotational movement between the coupling device  100  and the gear  200  subsequent to their being operably engaged. Retainers  20  could be formed in numerous different shapes and still provide the functionality as described herein. Furthermore, it is contemplated within the scope of the present invention that although four retainers  20  are illustrated in the drawings submitted herewith any number of retainers  20  could be formed with the body  10  and provide the same or similar function. 
     Four grooves  30  are formed into the body  10  and each extend longitudinally along the body  10  with each having a first end  31  proximate a corresponding retainer  20  and an opposing end  32 . The grooves  30  function to provide consistent wall thickness between the channels  40 ,  41  and  42  for better moldability. It is contemplated within the scope of the present invention that the coupling device  100  can achieve its desired function as described herein without the presence of the grooves  30 . While coupling device  100  is illustrated herein with four grooves  30 , it is contemplated within the scope of the present invention that body  10  could be manufactured with any number of grooves depending upon the design of the component with which the coupling device  100  will be engaged. Furthermore, the shape of grooves  30  could be manufactured in numerous different shapes and still achieve the desired functionality as described herein. 
     A spline  80  is present parallel to grooves  30  and between channels  41  and  42 . The spline  80  extends longitudinally substantially the length of the body  10  and extends outward from the body  10  in an angular manner. The spline  80  functions to engage with a mateably shaped notch of the gear  200  so as to substantially inhibit the rotational movement between the gear  200  and the coupling device  100 . It is contemplated that the spline  80  could be manufactured having numerous configurations of length and could extend outward from the body  10  at numerous different angles. While good results have been achieved utilizing one spline  80 , it is contemplated within the scope of the present invention that any number of splines  80  could be integrally formed with the body  10  in order to achieve the desired function as described herein. It is further contemplated within the scope of the present invention that the coupling device  100  could be manufactured such that a spline  80  is not necessary to reduce the rotational movement between the coupling device  100  and any device with which the coupling device  100  is operably engaged. 
     Three channels  40 ,  41  and  42  are integrally formed in the interior of the body  10  and extent longitudinally along the interior of the body  10 . The channels  40 ,  41  and  42  function to engage the ribs  210  that are disposed along the exemplary shaft  205  as shown in  FIG. 3 . Subsequent to the shaft  205  being inserted through the opening  70  of the body  10  and the coupling device  100  being traversed along to the desired location on the shaft  205  the channels  40 ,  41  and  42  will engage with the ribs  210  on the shaft  205  and inhibit rotational movement between the shaft  205  and the coupling device  100 . While the coupling device  100  illustrated herein has three channels shown, it is contemplated within the scope of the present invention that the actual number of channels within the body  10  of the coupling device  100  will be dependent upon the number of ribs  210  along exemplary shaft  205 . Exemplary shafts such as the shaft  205  utilize ribs  210  to achieve constant wall thickness for better moldability. However not all shafts utilize ribs in their design. Although the exemplary shaft  205  illustrated herein has ribs  210  and the coupling device  100  has channels  40 ,  41  and  42  configured to engage therewith, it is contemplated within the scope of the present invention that the coupling device  100  could be designed with no channels so as to form a mateable shape with a shaft having no ribs (i.e. cylindrical, circular cross section). In this design the coupling device  100  would have an interior shape mateable to the exterior shape of the shaft. More specifically but not by way of limitation the shape could be C-shaped. A designer&#39;s discretion would determine what depth of channels  40 ,  41  &amp;  42  to use for the rotational locking function of device  100  to shaft  205 , and consequently the height of ribs  210  may be driven by this consideration rather than moldability. Similarly, if a cylindrical shaft with no ribs were chosen, a spline similar to  80  but protruding into the interior  75  of device  100 , and a mating groove in shaft  205  could provide the rotational locking function of device  100  to shaft  205 . 
     Integrally formed with the body are hinges  50  each being located adjacent and on opposing sides of the channel  41 . The hinges  50  facilitate the operable coupling of a shaft  205  and a desired component such as but not limited to a gear  200 . The body  10  of coupling device  100  is manufactured from a durable and flexible material such as the aforementioned polypropylene. In use, a user applies an outward pressure on edges  11  and  12  of coupling device  100  in generally opposing directions allowing the interior  75  of the body  10  to be opened to accommodate shaft  205 . In this state, the hinges  50  flex in order to make the opening  70  slightly wider than the shaft  205  thus allowing a user to journal a shaft  205  therethrough and subsequently traverse the coupling device  100  across the shaft  205  to the desired position. Ensuing the release of the outward pressure on the edges  11  and  12  the hinges  50  compress and the body  10  of the coupling device  100  returns substantially to its original state providing a relatively zero tolerance frictional union between the coupling device  100  and the shaft  205 . In this position on the shaft  205 , the channels  40 ,  41  and  42  engage with the ribs  210  to substantially limit the rotational movement of the coupling device  100  with respect to the shaft  205  as the shaft  205  is rotated. The compression force of the hinges  50  further inhibits any longitudinal movement of the coupling device  100  along the shaft  205 . 
     Subsequent to the coupling device  100  being secured to its desired position on the shaft  205 , the user will insert the shaft  205  and coupling device  100  through an opening  225  of an exemplary component such as the gear  220 . The opening  225  of the gear  200  is shaped to receive the coupling device  100  therethrough and further includes mateable shapes so that the gear  200  operably connects with the spline  80  and retainers  20 , and, so the flat  230  inside gear  200  is brought in correct compressive contact with the flat region on the tip  212  of rib  210 . It is conceived that variations of the invention can function relying upon both spline  80  and flat  230 , or one or the other alone. As the coupling device  100  is journaled through the opening  225  of the gear  200  the hinges  50  compress between shaft  205  and gear  200  the further compression of coupling device  100  inhibits the slippage of gear  200  rotationally or lengthwise along shaft  205 . The hinges  50  adjacent to channels  40  and  42  are on opposing sides of the shaft  205  in order to provide balance and centering of the gear  200  so that the centerline of gear  200  is coincident with the centerline of the shaft  205 . The hinges  50  adjacent to channel  41  provide the compressive force to hold flat  230  inside gear  200  in contact with the tip  212  of rib  210 . 
     While the hinges  50  are generally angular in shape it is contemplated within the scope of the invention that numerous different shapes of hinges  50  could be utilized to achieve the functionality as described herein. Furthermore, it is contemplated within the scope of the present invention that numerous different configurations, shapes, and quantities of the channels  40 ,  41 , and  42 , grooves  30  and hinges  50  could be utilized to achieve the desired functionality of the coupling device  100  as described herein. Additionally, while the exemplary embodiment of the coupling device  100  is intended for use in the printer  5 , it should be recognized that the coupling device  100  could be employed in numerous different systems or apparatuses wherein an operable connection between a shaft and a component are required wherein the user desires to substantially inhibit the rotational and longitudinal movement of the component with respect to the shaft or an alternate shaft design is desired. It is further contemplated within the scope of the present invention that although a gear  200  is illustrated herein ( FIGS. 3 and 4 ) to be operably coupled to the shaft  205  numerous other components could be coupled to the shaft  205 . More specifically but not by way of limitation, a pick tire  250  ( FIG. 5 ), a roll  260  ( FIG. 6 ), a wheel  270  ( FIG. 7 ), a pulley  280  ( FIG. 8 ) or a cam  290  ( FIG. 9 ) could be operably coupled to the shaft  205  utilizing the coupling device  100  as described herein. 
     In the preceding detailed description, reference has been made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments, and certain variants thereof, have been described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other suitable embodiments may be utilized and that logical changes may be made without departing from the spirit or scope of the invention. The description may omit certain information known to those skilled in the art. The preceding detailed description is, therefore, not intended to be limited to the specific forms set forth herein, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents, as can be reasonably included within the spirit and scope of the appended claims.