Abstract:
A disposable ink ribbon cartridge for use in a shorthand machine. The cartridge includes an endless loop ribbon threaded through an advancing mechanism in contact with a movable ink reservoir. The advancing mechanism advances the ribbon and also transfers ink from the ink reservoir to the ribbon. The ink reservoir is made from a reticulated foam which provides an even supply of ink over a long period of time. The movable ink reservoir and the advancing mechanism interact to minimize friction between the moving parts of the cartridge. The ink reservoir and advancing mechanism deliver consistent and even doses of ink to the ribbon throughout the life of the cartridge.

Description:
This application is a continuation application of U.S. patent application Ser. No. 08/768,091 filed Dec. 16, 1996, now U.S. Pat. No. 6,422,771, which is a continuation application of U.S. patent application Ser. No. 08/581,308 filed on Dec. 28, 1995, now abandoned, which is a continuation application of U.S. patent application Ser. No. 08,389,739 filed on Feb. 15, 1995, now abandoned, which is a continuation application of U.S. patent application Ser. No. 08/091,533 filed on Jul. 14, 1993, now abandoned, which is a continuation application of U.S. patent application Ser. No. 07/822,638 filed on Jan. 17, 1992, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates in general to ink ribbons used in shorthand machines. In particular, this invention relates to an efficient and disposable ribbon cartridge for use in shorthand machines. 
     Shorthand machines are commonly used to record spoken words in a visual form. For example, stenographers typically use shorthand machines to record statements made in depositions, hearings and other court-related proceedings. Shorthand machines manufactured by the assignee of the present invention have operated successfully and efficiently for many decades. 
     The conventional shorthand machine has a keyboard of twenty-two phonetically-related characters which, to the skilled operator, provides all combinations necessary to record words and numbers. The record produced by the machine may be a paper tape on which the phonetic characters are printed, or the characters may be recorded on a magnetic tape medium. One example of paper recording is generally described in U.S. Pat. No. 2,319,273, which was assigned to the predecessor of the assignee of the present invention. One example of magnetic recording is generally described in U.S. Pat. Nos. 3,557,927 and 4,205,351, also assigned to the assignee of the present invention. 
     To record a word or parts of a word in a conventional shorthand machine, the machine operator presses an appropriate combination of the keys, and the machine mechanically prints the characters simultaneously on a paper tape, or in the case of electric recordation, combinations of electrical pulses are recorded on a magnetic tape or disk medium. For paper tape recordation, the keys actuate associated type bars to cause the type bars to impact on an inked ribbon to print characters on the paper. 
     The ribbon for a shorthand machine is typically an “endless loop” design. The general principal of the endless loop is to utilize a single ribbon in a closed circle as described and illustrated in U.S. Pat. No. 2,319,273 (&#39;273 patent). The entire disclosure of the &#39;273 patent is incorporated herein by reference. 
     As best shown in FIG. 5 of the &#39;273 patent, the ribbon 28 passes around a ribbon spool 173 and between a platen 27 and a set of type bars 73. A fabric 196 is wrapped around the core of the spool to absorb ink from the spool and impart the ink to the ribbon as it contacts the fabric. Ink is provided to the spool via openings in the top of the spool. The user must periodically replenish the ink in the spool through the openings. A pair of ribbon pressure rolls 222 and 223 force the ribbon against the ink-filled fabric on the spool. A mechanical connection (described in detail at col. 11, line 16 to col. 12, line 27) between the spool and the keys rotates the ribbon spool whenever keys are pressed, thereby advancing the ribbon around the spool (via pressure rolls) and through the print area. The platen 27 holds paper for printing, and the type bars 73 are each associated with one of the keys. When a key is pressed, the associated type bar is urged toward the platen, thereby urging the ribbon into contact with the paper on the platen for printing characters on the paper. 
     In contrast to the typical synthetic typewriter ribbon, which is inked and printed once, the endless loop ribbon is made from an absorbent fabric which is continuously cycled through the print area and replenished with ink. Thus, a given area of the endless loop ribbon is printed on several thousand times during the useful life of the ribbon. 
     Although a significant amount of a shorthand machine&#39;s functions are controlled electronically, many functions—such as ribbon advancement, print hammer movement and platen advancement—are controlled mechanically, or at least provided with a mechanical (manual) mode. Having mechanical functions allows the shorthand machine to be used in places where electrical service is non-existent, inconvenient, or unreliable. Additionally, the mechanically driven functions typically make less noise than the electrically driven functions. This is important because in most applications, particularly in court reporting, it is essential that the shorthand machine operates as quietly as possible. 
     Because the endless-loop ribbon is advanced mechanically by pressing the keys, it is important to minimize the force required to advance the ribbon. Thus, it is advantageous to provide a minimum amount of friction between the moving parts of the advancing mechanism so that the force required to depress the keys is also minimized. 
     The Xscribe Corporation has sold an endless-loop-based cartridge for use with its Stenotype® family of shorthand machines. The Stenotype cartridge includes a relatively long ribbon which is folded at right angles to create a 90° change of direction for the ribbon. The ribbon is advanced through the cartridge by passing between and engaging a drive gear and an idle gear. The idle gear transfers ink to the ribbon by rubbing against a stationary ink-holding foam stem which acquires its ink from an apparently rectangular and stationary ink reservoir. 
     Several problems are associated with the Stenotype® cartridge, the most important of which is the amount of force required to advance the ribbon through the cartridge. For example, the contact between the stationary ink stem and the idle gear creates a significant amount of unwanted friction in the advancing mechanism. Additional friction is generated when the ribbon is pulled through its 90° bend. Also, the extremely long ribbon is confined within the relatively small Stenotype® cartridge by providing a holding area for the ribbon inside the cartridge. The ribbon is literally bunched and packed into the holding area and must be pulled through this area by the single drive/idle gear combination. Thus, the Stenotype® machine includes a motor driven ribbon advancing mechanism (electric mode) in addition to a mechanical key-driven ribbon advancing mechanism (manual mode). In the manual mode, the force required to depress the Stenotype&#39;s keys could become unacceptable for the operator during extended use. 
     Additionally, the Stenotype cartridge&#39;s ribbon tends to have heavy ink in some areas and light ink in other areas, resulting in a rather messy cartridge and inconsistent print quality. This is apparently due to the fact that the ribbon is bunched in the holding area such that ink is allowed to migrate randomly from one portion of the ribbon to another. Also, the stationary ink stem is itself easily saturated with ink from the ink reservoir, resulting in a non-uniform transfer of ink to the idle gear and further contributing to inconsistent print quality. 
     Thus, it is an object of the present invention to provide an endless-loop ribbon cartridge that takes full advantage of the benefits associated with utilizing a cartridge. It is also an object of the present invention to provide an endless-loop ribbon cartridge that does not significantly increase the amount of force required to depress the shorthand machine&#39;s keys. It is a further object of the present invention to provide a ribbon cartridge that supplies an even distribution of ink to the ribbon. Additionally, it is an object of the present invention to provide a ribbon cartridge having a relatively long life and requiring little or no maintenance. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a disposable ribbon cartridge for use in a shorthand machine. The cartridge comprises a housing having an endless loop ribbon extending through a prescribed pathway in the housing. An advancing mechanism advances the ribbon through its prescribed pathway, and also transfers ink from a movable ink reservoir to the ribbon. The ink reservoir is preferably made from a reticulated and felted polyurethane foam having specific wicking properties. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in greater detail in the following description of the preferred embodiment, taken in conjunction with the drawings, in which: 
     FIG. 1 shows a shorthand machine for use with the ribbon cartridge embodying the present invention; 
     FIG. 2 shows the shorthand machine of FIG. 1 with its cover open. A user is placing a ribbon cartridge embodying the present invention inside the shorthand machine; 
     FIG. 3 is a top perspective view of the ribbon cartridge shown in FIG. 2; 
     FIG. 4 is a bottom perspective view of the ribbon cartridge shown in FIG. 2; 
     FIG. 5 a  is a top plan view of the cartridge shown in FIG. 2 with its top portion removed; 
     FIG. 5 b  is an exploded view of the components of the ribbon cartridge shown in FIG. 2; and 
     FIG. 6 is a perspective view of the drive gear shown in FIGS. 5 a  and  5   b.    
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Operating Environment 
     This invention may be implemented in any conventional shorthand machine. The embodiment disclosed herein is particularly suitable for use with the Stenograph® STENTURA™ family of shorthand machines, an example of which is illustrated in FIGS. 1 and 2. Many of the mechanical and electrical features of the STENTURA™ are described in U.S. Pat. Nos. 2,319,273; 3,557,927; 4,205,351; 4,421,427 and 4,363,558, and the entire disclosure of each of these patents is incorparted herein by reference. Additional details regarding the STENTURA™ are described in co-pending, commonly assigned U.S. patent application Ser. No. 07/822,293, filed Jan. 17, 1992, entitled “Method and Apparatus for Recording and Translating Shorthand Notes.” The entire disclosure of application Ser. No. 07/822,293 is incorporated herein by reference. 
     A shorthand transcribing machine for use with the ribbon cartridge embodying the present invention is illustrated in perspective in FIG.  1  and is designated in general by the reference numeral  1 . The shorthand machine  1  is shown in FIG. 2 with its cover raised, exposing the ribbon cartridge  10  embodying the present invention in place inside the machine  1 . In general, the shorthand machine  1  includes a keyboard  2  having a plurality of keys which, when stroked by an operator, produce a paper tape record of the words recorded. Each key represents an alpha-numeric symbol which is reproduced at the paper tape when the key is stroked by the operator. 
     The paper tape (not shown) is carried over a rubber platen  3 . A type bar  4  is associated with each key and is advanced toward the platen  3  when the particular key is stroked. The cartridge  10  includes an internal advancing mechanism  50  (shown in FIGS. 5 a  and  5   b ) for feeding an inked ribbon  48  between the type bars  4  and the platen  3 . The advancing mechanism  50  is driven by a mechanical connection to the keys so that the ribbon  48  is advanced each time a key is depressed. Also, the paper tape is advanced by a mechanically or electrically driven mechanism for rotating the platen  3  each time the one or more of the keys is stroked. The type bars associated with the stroked keys urge the inked ribbon into contact with the paper at the platen  3  for impressing an ink symbol thereon. 
     As shown in FIG. 2, the cartridge fits directly under the cover  5  in the area previously occupied by the ink spool and pressure rolls described in the &#39;273 patent. The cartridge  10  is secured in the machine  1  by tabs  44  located on the sides of the cartridge. The cartridge  10  is conveniently held by grasping the tabs  44  with the thumb and index fingers. The tabs  44  are then pressed toward one another as the cartridge  10  is lowered. The tabs  44  move past and then engage a pair of complementary flanges (not shown) in the machine  1 . 
     FIG. 4 illustrates a perspective view of the bottom of the cartridge  10 . A small opening  34  in the cartridge  10  exposes the drive teeth  62  on the advancing gear  52 . When the cartridge  10  is in place inside the machine  1 , a pinion  66  (shown in FIG. 6) engages the teeth  62 . A mechanical connection (not shown) between the pinion  66  and the keyboard  2  rotates the pinion  66  whenever a key is depressed, thereby rotating the advancing gear  52  and advancing the ribbon  48 . An ink reservoir  112  (shown in FIGS. 5 a  and  5   b ) is located inside the cartridge  10  and continuously and evenly provides ink to the ribbon  48  in a manner to be described. 
     Cartridge Construction 
     The cartridge  10  includes two sections  12 ,  22 , best illustrated in FIG. 5 a . The top section  12  generally includes a pair of arms  14  and a body  15 . The bottom section  22  of the cartridge  10  includes a pair of arms  24 , a body  25 , a series of small cavities  26  and a gear holder  28 . The cavities  26  engage complementary knobs  16  in the top section  12  to help secure the two sections  12 ,  22  together. The top and bottom section  12 ,  22  may be bonded together in any manner, preferably by ultrasonic welding. A barrier  30  defines part of the endless loop path of the ribbon  48 , and also isolates the ink reservior  112  from the ribbon  48 . A bearing stem  32  engages the ink reservoir bearing  106  for holding the ink reservoir  112 . A hole  34  is provided in the bottom section  22  to allow access to the advancing gear  52 . A biasing barrier  36  is provided to bias a spring  118  against a holder  92  which in turn, biases a following gear  72  against the advancing gear  52 . The barrier  36  includes side portions  38 ,  40 , and a middle notch  42 . 
     The ribbon  48  is an endless-loop ribbon which travels along a pathway that extends through the cartridge  10  and exits the cartridge at the arms  12 ,  24 . The exposed portion of the ribbon  48  between the arms  14 , is passed over the platen  3  (see FIG. 2) when the cartridge  10  is in place in the machine  1 . 
     The advancing mechanism  50  generally comprises an advancing gear  52  and a following gear  72 . The advancing gear  52  includes a cylindrical upper half  54  and a cylindrical lower half  56  separated by a middle portion  58 . Side ridges  60  are located around the circumference of the upper half  54  and lower half  56 . Bottom advancing teeth  62  are located along the bottom face of the lower half  56  and engage the pinion  66  when the cartridge  10  is in place inside the machine. A flange  46  is attached to the bottom portion  22  of the cartridge  10  and engages the advancing gear  52  in its middle portion  58  for loosely holding the advancing gear  52  in place. A cylindrical stem portion  64  in the upper half  54  of the advancing gear  52  is provided for engaging a complementary cavity (not shown) in the top portion  12  of the cartridge  10 . 
     The following gear  72  is structurally similar to the advancing gear  52 . The following gear  72  includes a cylindrical upper half  74  and a cylindrical lower half  76 , with the two halves separated by a middle portion  78 . Side ridges  80  are located along the outer circumference of the upper half  74  and lower half  76 . A cylindrical stem portion  90  extends from the upper half  74  for engaging a complementary cavity (not shown) in the top portion  12  of the cartridge  10 . 
     A gear holder  92  holds the following gear  72  in place inside the cartridge  10 . The gear holder  92  generally includes a gear notch  94 , a spring knob  96  and a stabilizing stem  98 . The gear notch  94  engages the middle portion  78  of the following gear  72 . The spring  118  engages the spring knob  96  at one end of the spring  118 . The other end of the spring  118  is biased against the barrier  36  and around the middle notch  42 . Side portions  38 ,  40  of the spring barrier  36  limit the lateral movement of the spring  118  when the spring  118  is engaged over the notch  42 . The stabilizing stem  98  generally includes a top portion  100  and a bottom portion  102 . The top portion  100  of the stabilizing stem  98  engages a complementary cavity (not shown) in the top portion  12  of the cartridge  10 . The bottom portion  102  of the stabilizing stem  98  engages a cavity  26  in the bottom portion  22  of the cartridge  10 . Thus, the stabilizing stem  98  secures the gear holder  98  in place between the top portion  12  and the bottom portion  22  of the cartridge  10 , thereby securing the following gear  72  in place inside the cartridge  10 . 
     The ink reservoir  112  is preferably cylindrical and made from a reticulated and felted polyurethane foam having specific wicking properties. The reservoir  112  includes a stem opening  114  and an ink transfer surface  116  extending around the circumference of the reservoir  112 . The ink reservoir  112  snugly engages the stem portion  108  of the bearing  106  through the opening  114 . The flat bottom portion  110  of the bearing  106  contacts with the bottom portion of the ink reservoir  112 . The bearing stem  108  is essentially hollow, thus, allowing it to fit over a stem  32  in the bottom portion  22  of the cartridge  10 . 
     Materials and Dimensions 
     In the preferred embodiment, the body  11  is approximately 3 inches by 2 inches by 1¼ inches. The arms  13  are approximately 2 inches long and 1¼ inches in thickness. The advancing gear  52  is approximately {fraction ( 5 / 8 )} inches high and ½ inches in diameter. The side ridges  60  are preferably sized to fit approximately sixty ridges around the circumference of each cylindrical half,  54 ,  56  of the advancing gear  56 . The ridges  60  can have a pitch of 120, a pressure angle of 20° and a pitch diameter of 0.500. The following gear  72  is preferably approximately ½ inches high and ⅜ inches in diameter. The side ridges  80  are preferably sized to fit approximately 43 ridges around the circumference of each cylindrical half,  74 ,  76  of the following gear  72 . The ridges  80  can have a pitch of 120, a pressure angle of 20° and a pitch diameter of 0.358. The ink reservoir  112  is approximately ½ inches high and 1½ inches in diameter. The ribbon  48  is approximately ⅜ inches wide and 10 inches in circumference. 
     The cartridge body  11  may be made from any lightweight yet sturdy material, and is preferably made from ABS plastic sold by General Electric. The small movable parts such as the gears  52 ,  72 , holder  92  and bearing  106  are preferably a chemically inactive resin such as Delrin™ sold by DuPont. 
     The ink reservoir  112  is 90 pores per inch foam that is reticulated and compressed to a firmness rating of 6 (i.e., ⅙ its original volume). The foam has an 88% void volume and a wick height of 4.2 inches of oil in 72 hours. A suitable foam is available from a company known as Scott Foam having a place of business in Eddystone, Pa. 
     General Operation 
     In operation, the following gear  72  is spring biased against the advancing gear  52  which is in turn unbiased against the ink reservoir  112 . The side ridges  60  of the advancing gear  52  engage the side ridges  80  of the following gear  72 . The ribbon  48  is engaged between the side ridges  60 ,  80  of the advancing gear  52  and following gear  72  respectively. 
     The ink reservoir  112  is filled with ink prior to assembly of the cartridge  10 . This may be accomplished by exposing the reservoir to ink, in a dish for example, and waiting for the ink to migrate throughout the reservoir. As the advancing gear  52  is rotated by the pinion  66  in response to a keystroke, the ink reservoir  112  and bearing  106  are rotated around the bearing stem  32  by the advancing gear  52 . The advancing gear  52  thus continuously contacts advancing portions of the ink reservoir  112 , and the side ridges  60  of the advancing gear  52  carry ink to the ribbon  50 . 
     Thus, the advancing mechanism  50  performs several functions. The advancing gear  52  advances the ribbon  48  in conjunction with the following gear  72 . The advancing gear  52  also advances the ink reservoir  112 , continuously contacting advancing portions of the ink reservoir  112  and carrying ink from the ink reservoir  112  to the ribbon  48 . The coefficient of friction for the mechanism  50  is thus minimized since the elements that contact the advancing gear  52 —namely the ink reservoir  112 , the ribbon  48  and the following gear  72 —all move with the advancing gear  52 . 
     Also, ink is carried to the ribbon  48  in an even and metered fashion by the side ridges  60  of the advancing gear  52 . There is no direct contact between the ribbon  48  and the ink reservoir  112 , and thus the amount of ink transferred to the ribbon  48  is primarily controlled by 1) the size and spacing of the ridges  60 ; and 2) the wicking properties of the ink reservoir  112 . By rotating the reservoir  112  as it picks up ink, the advancing gear  52  delivers a consistent and even amount of ink to the ribbon  48  over the useful life of the cartridge  10 . Thus, the ribbon is not over-exposed to ink, and the ink stays in the ribbon rather than overflowing to the exterior of the cartridge creating a messy work area. Also, the cylindrical geometry of the rotating reservoir  112  mean that the maximum wicking distance to the ink transfer surface  116  is approximately equal to the radius of the cylinder  112 . 
     Although the present invention has been described with reference to a preferred embodiment, it will be clear to one of ordinary skill in the art that certain rearrangements and modifications might be made within the scope of the invention. All such modifications and their equivalents are intended to be covered by the appended claims.