Abstract:
Described is a writing instrument-caliper system composed of a fully functional writing instrument and a separate caliper device. The writing instrument and caliper device are of such construction that the caliper device can be inserted snugly into the open-ended hollow barrel of the writing instrument for safe storage. With the caliper device in its storage location, the writing instrument-caliper system is of similar outer physical dimensions to the writing instrument alone, and can be carried safely in a shirt pocket without risk of injury to the user or it can be employed as a fully functional writing instrument. With the caliper device removed from its storage location, the writing instrument and caliper device can be employed in parallel, allowing the user to make written notations while simultaneously making measurements with the caliper device. This writing instrument-caliper system overcomes many of the problems encountered by prior art devices.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application seeks the benefit of provisional application No. 60/362,262 filed Mar. 7, 2002 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX  
         [0003]    Not applicable.  
         BACKGROUND OF THE INVENTION  
         [0004]    The invention relates to a writing instrument-caliper system that is especially useful to a physician (or other person) who must write large amounts of information as well as make frequent precise measurements.  
           [0005]    A physician frequently carries both a writing instrument and sheathed calipers in his/her pocket. The sheath is in place so as to protect the physician from the sharp end points of the caliper legs. When the physician wishes to measure intervals or distances on an electrocardiogram (ECG), he/she removes the calipers from his/her pocket and un-sheaths them. The sharp end points of the calipers are deployed to measure distances or intervals on the ECG. The sharp end points are then used to compare the measured distance or interval to other similar distances or intervals. Alternatively, the sharp end points can be held against a numerical scale to obtain a numerical measurement of the distance or interval. The physician then removes a writing instrument from his/her pocket and deploys it to record these measurements in the patient&#39;s medical record. Frequently, the sheath for the dividers is misplaced and lost. This prevents the physician from returning the dividers to the pocket of his/her clothing because of the risk of the sharp end points piercing the physician&#39;s skin. It would be useful to a physician (or other person who makes frequent measurements from a chart or graph) to have a single device or a system that could be deployed both as a caliper and as a writing instrument.  
           [0006]    U.S. Pat. No. 1,564,908 discloses calipers with a bracket for holding a writing instrument the tip of which is adjacent to one of the sharp points of the calipers.  
           [0007]    U.S. Pat. No. 4,720,921 discloses calipers used as a navigational instrument, with a channel in the structure for frictionally receiving a writing instrument that can be gripped, removed from the channel, inverted, and reinserted with its writing tip protectively inside the channel. The disclosed navigational device includes various indicia that enable it to function as a protractor and as a distance-measuring device. Although the navigational instrument incorporates a writing instrument and calipers, it would not be suitable for use by physicians, because the divider tips are unprotected by a sheath when not in use, and the writing tip cannot be protected except by removing the writing instrument, inverting it, and reinserting it in the receiving channel, which would be more inconvenient than the present practice of using a separate sheathed caliper and a conventional writing instrument.  
           [0008]    U.S. Pat. No. 4,815,881 discloses a multi-purpose combination writing instrument which can serve as a straight edge, a compass and a writing instrument. This device can be deployed as a writing instrument for general drawing or notation, or after some modification it can be deployed as a compass to draw arcs or circles, or it can be disassemble to be used as a straight edge and writing instrument to draw straight lines. This device is composed of a compass in which each leg takes the form of a half-hexagon in cross section. When the half-hexagonal compass legs are brought together and the compass is fully closed, the legs combine to form a hollow tube, which is hexagonal in cross section. A writing instrument can be movably placed between the legs of the compass and a protective cap can be placed over the tip of the writing instrument. The single sharp end point must be removed from the compass legs in order for the writing instrument to be placed between the half-hexagonal compass legs. The sharp end point can be placed in the cap for storage.  
           [0009]    U.S. Pat. No. 5,115,571 discloses a reversible pen-caliper device and method for use by cardiologists that can be used as a caliper to measure distances on a chart or ECG, can then be reversed and utilized as a pen to make notations regarding these measurements, and then can be safely carried in a shirt pocket without poking through the clothing and skin of the user. Specifically, this device includes a retractable ballpoint pen assembly, an oppositely disposed caliper assembly, and a snug-fitting rigid sheath that is slidable over either the caliper assembly or the pen assembly. This arrangement allows the user to place the sheath over the pen assembly for safe keeping while using the calipers. This arrangement also allows the user to place the sheath over the caliper assembly so the pen-caliper can be safely carried on the body. While this arrangement allows for a compact device that is capable of functioning both as a pen and a caliper, the functionality of both the pen and caliper are compromised by this design. When using the device as a caliper, the device is gripped at some point along the barrel of the pen, either with or without the caliper&#39;s protective sheath in place. The pen barrel is fixedly attached to the caliper, and adds excessive weight and length to the gripping area of the device when used as a caliper. This weight and length reduces the fine control of the device when it is deployed as a caliper, thus limiting the user&#39;s ability to make accurate measurements on an ECG. The current device has attempted to overcome the heavy weight of the caliper, which was outlined above, by decreasing the diameter of the pen barrel. While this does increase the devices functionality as a caliper by a small margin, it greatly decreases the devices functionality as a pen. The resultant small size of the pen grip makes the device when used as a pen unsuitable for sustained writing, as the users hand will quickly fatigue. Additionally, the small size of the pen barrel limits the size of the pen refill, which makes this device suitable only for making short notations. However, because a physician will write reams of information in the medical record over the course of a normal day he/she will out of necessity need to carry a separate instrument that is more suited to sustained writing. Additionally, this device can only be employed serially as a caliper or a pen—it cannot be used as a caliper and a writing instrument in parallel. If the user wishes to make a notation while simultaneously employing the caliper to make a measurement from a graph, he/she must use a second writing instrument to make this notation. The device disclosed in U.S. Pat. No. 5,115,571 would not eliminate the need for the physician to carry a second writing instrument in addition to this pen-caliper device.  
           [0010]    None of the foregoing devices satisfactorily fill the needs of a physician who must carry both a writing instrument and calipers. It would be desirable for a physician and others to have a single instrument which can be used as calipers for measuring distances on ECGs or the like and can be used as comfortable writing instrument.  
         BRIEF DESCRIPTIONS OF THE INVENTION  
         [0011]    It is the object of the disclosed invention to provide a writing instrument-caliper system that can be utilized as a writing instrument, can also be used as a caliper to measure and compare distances on a chart or ECG, and can be safely carried in a shirt pocket without risk of the caliper points poking through the clothing and skin of the user.  
           [0012]    Briefly described, and in accordance with one embodiment thereof, the invention provides a pen-caliper system which includes a pen device and a caliper device integrated into a single unit. The pen device is constructed such that the pen barrel is hollow and of sufficient size so as to snugly receive the caliper device. The arms and sharp end-points of the caliper therefore rest within the confines of the pen barrel for safekeeping. The system can be deployed as a writing instrument while the caliper is either in or out of its storage position in the hollow barrel of the pen device. To deploy the caliper, the caliper device is removed from the pen barrel and employed as an independent instrument, hence ensuring the functionality of the caliper by maintaining a relatively small size and low weight which is not encumbered by being fixedly attached to the pen device. This writing instrument-caliper system can be employed as a caliper and a writing instrument in parallel, thus allowing the user to make notations while simultaneously deploying the system&#39;s caliper.  
           [0013]    The pen device having a pen barrel, a ballpoint ink cartridge in the barrel, and a mechanism engaging the ink cartridge and the barrel to advance the ink cartridge when the pen barrel is rotated so as to position a ballpoint tip of the ink cartridge for writing. The mechanism also effectuates retracting of the ballpoint tip into the pen barrel when the pen barrel is rotated in the opposite direction. The barrel of the pen opposite to the pen nib is hollow and capable of receiving the caliper device.  
           [0014]    The caliper device has first and second caliper arms each having a pointed tip, and first and second gear elements attached to pivot ends of the first and second caliper arms, respectively. The first and second gear elements engage each other to cause symmetrical opening and closing of the first and second caliper arms. A pivot support is used to support first and second pivot elements, which pivotally connect the pivot ends of the first and second caliper arms to the pivot support. The caliper device can be inserted snuggly into the end of the pen device barrel such that the barrel serves as a rigid protective sheath for the caliper.  
           [0015]    A user can remove the caliper device from the pen barrel to expose the first and second caliper arms. The user later can place the caliper device into the pen device barrel and retract the ballpoint tip so the pen-caliper system can be safely carried in a pocket of a user&#39;s clothing or the like. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a partial cutaway diagram illustrating the prior art as disclosed in U.S. Pat. No. 5,115,571.  
         [0017]    [0017]FIG. 2 is a diagram of the pen-caliper system of the invention with the caliper device removed from its storage space.  
         [0018]    [0018]FIG. 3 is a side view diagram of the pen-caliper system of the invention with the caliper device located in its storage space and the pen cap in place over the pen tip.  
         [0019]    [0019]FIG. 4 is a top view diagram of the pen-caliper system of the invention with the caliper device located in its storage space and the pen cap in place over the support element of the caliper device.  
         [0020]    [0020]FIG. 5 is a top view diagram and a side view diagram of the caliper device.  
         [0021]    [0021]FIG. 6 is a partial cutaway of the caliper device demonstration the gear mechanism of the caliper arms.  
         [0022]    [0022]FIG. 7 is an exploded view of the pen device.  
         [0023]    [0023]FIG. 8 is a diagram of the alternate twist-actuated pen device for the invention.  
         [0024]    [0024]FIG. 9 is an exploded view of the alternate twist-actuated pen device.  
         [0025]    [0025]FIG. 10 is a partially assembled view of the alternate twist-actuated pen device.  
         [0026]    [0026]FIG. 11 is a partially assembled view of the alternate twist-actuated pen device with the pen device configured for writing.  
         [0027]    [0027]FIG. 12 is a partially assembled view of the alternate twist-actuated pen device with the pen device configured for carrying. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]    [0028]FIG. 1 demonstrates the prior art in which a pen-caliper device D includes a ballpoint pen assembly P fixably attached to an oppositely directed caliper assembly C. A protective sheath S is also provided which can be snuggly fit over the caliper assembly C to protect the user from the sharp endpoints E of the caliper, or over the pen assembly P for safe keeping while the caliper C is deployed.  
         [0029]    [0029]FIG. 2 demonstrates the pen-caliper system  10  of the current invention composed of the fixed nib pen device  11 , the pen cap  12 , and the caliper device  20 . With the pen cap  12  removed from the pen tip  17  as shown, the pen nib  39  is exposed. The pen tip  17  has a circumferential elevation  18  on its outer surface which is mated to a circumferential depression  14  (FIG. 7) on the interior surface of the pen cap  12  allowing the pen cap  12  to snap firmly into place over the pen tip  17 . The pen barrel  13  is hollow and of such internal design so as the snuggly receive the caliper device  20  for safekeeping and storage. With the caliper device  20  removed from its storage location in the hollow barrel  13  of the fixed nib pen device  11 , the caliper arms  22  and  22 ′ and their respective sharp endpoints  21  and  21 ′ are exposed.  
         [0030]    [0030]FIG. 3 demonstrates a side view of the pen-caliper system  10  in its closed configuration. The pen cap  12  is in place over the now concealed pen tip  17 . The caliper device  20  is in its storage position within the hollow pen barrel  13  such that only part of the support element  26  of the caliper device  20  is visible. A pocket clip  15  is attached to the right end portion of the hollow barrel  13 . In this closed configuration the pen-caliper system  10  may be safely carried in a shirt pocket. FIG. 4 demonstrates a top view of the pen-caliper system  10  in its writing configuration. The pen cap  12  removed from the pen tip  17  and placed snuggly over the exposed portion of the support element  26  of the caliper device  20  concealing the support element  26  from view. In the configuration shown in FIG. 3, the pen-caliper system  10  may be used effectively as a writing instrument.  
         [0031]    Referring to FIGS. 2 and 5, the caliper device  20  is shown removed from its storage position in the hollow pen barrel  13  of the fixed nib pen device  11 . The caliper device  20  is composed of a support element  26  with bifurcations  24  and  24 ′, which support the gear sections  23  and  23 ′ of caliper arms  22  and  22 ′. Caliper arm  22  and gear section  23  rotate about a pivot pin  29  that extends through the bifurcations  24  and  24 ′ of the support element  26 . Similarly, caliper arm  22 ′ and gear section  23 ′ rotate about a pivot pin  29 ′ that extends through the bifurcations  24  and  24 ′ of the support element  26 . The teeth of gear section  23  mesh with the teeth of gear section  23 ′ so that when either of caliper arms  22  or  22 ′ is pivoted, the other arm symmetrically pivots an equal amount in the opposite direction by virtue of the gearing. The distal ends of caliper arms  22  and  22 ′ each have a sharp endpoint  21  and  21 ′ attached thereto.  
         [0032]    As shown in FIG. 2, the caliper device  20  can be removed to from the hollow barrel  13  of the fixed nib pen device  11 . The fixed nib pen device  11  can be left in the user&#39;s pocket while the caliper device  20  is deployed. When the caliper measurement has been made, caliper arms  22  and  22 ′ are pivoted closed, and the caliper device  20  is replaced in its storage position in the hollow barrel  13  of the fixed nib pen device  11 .  
         [0033]    [0033]FIG. 7 is an exploded view of the fixed nib pen device  11 . Demonstrated are the pen cap  12 , the pen tip  17 , the flexible pen refill  30 , the pen refill grip  40 , and the hollow pen barrel  13 . The interior surface of the pen cap  12  demonstrates the circumferential depression  14  which mates with the circumferential elevation  18  on the outer surface of the pen tip  17  allowing the pen cap  12  to snap firmly into place over the pen tip  17 .  
         [0034]    A serpentine tunnel  42  passes through the body of the pen refill grip  40 , entering in the center of the pen refill grip  42  at fore portion (not shown) and exiting off center at the aft portion. The flexible pen refill  30  is inserted into the serpentine tunnel  42  and enters the center of the fore portion of the serpentine tunnel  42  and exits off center in the aft portion of the serpentine tunnel  42 . This causes the shaft of the pen refill  30  to be off the center axis of the hollow barrel  13  of the fixed nib pen device  11  so as not to interfere with the caliper arms  22  and  22 ′ when the caliper is placed in its storage position within the hollow barrel  13 .  
         [0035]    The pen tip  17  is attached by external threads  18  to matching internal threads (not shown) in the fore portion of the pen barrel  13 .  
         [0036]    [0036]FIG. 8 demonstrates a twist actuated pen device  111  which can be substituted for the fixed nib pen device  11  in the pen-caliper system  10  disclosed earlier. As shown, the twist actuated pen in configured for writing with the pen nib  139  is exposed. By twisting the pen tip  117 , the pen nib  139  can be retracted into the pen barrel  113  of the pen device  111 . The pen barrel  113  is hollow and of such internal design so as the snuggly receive the caliper device  20  for safekeeping and storage. With the caliper device  20  removed from its storage location in the hollow barrel  113  of the pen device  111 , the caliper arms  22  and  22 ′ and their respective sharp endpoints  21  and  21 ′ are exposed.  
         [0037]    [0037]FIG. 9 is an exploded view of the twist actuated pen device  111  composed of a pen tip  117 , driving casing tube  160 , driving axial cylinder  170 , external casing tube  180 , pen refill  130 , pen refill gripper  190 , and pen barrel  113 .  
         [0038]    The pen tip  117  is an appropriately tapered hollow tube of such internal design so as to freely allow the passage of the pen refill  130  while also allowing the pen tip  117  to be fixedly attached to the for portion  162  of the driving casing tube  160  when assembled.  
         [0039]    The driving casing tube  160  is a hollow stepped tube composed of a relatively small diameter aft portion  161  and a relatively large diameter fore portion  162 . The aft portion  161  of the driving casing tube  160  is of such outer diameter so as to fit within the inner diameter of the external casing tube  180  and rotate and slide freely unless otherwise constrained. The fore portion  162  of the driving casing tube  160  is of such outer diameter so as to fit tightly in the inner diameter of the pen tip  117 . A concave ring  163  is provided in the middle section of the relatively small diameter aft portion  161  and the dimensions of this concave ring  163  are matched to the internal ridge formed by the depressed ring  183  of the external casing tube  180 . A sinuously curved slot  165  surrounds one half of the aft portion  161  of the driving casing tube at a suitable slanting angle, thus forming a fore most terminal portion  166  and an aft most terminal portion  167  at which the width of the slot can be enlarged.  
         [0040]    The driving axial cylinder  170  is a hollow stepped tube with a relatively large diameter head portion  171  and a relatively small diameter body portion  174 . The head portion  171  of the driving axial cylinder  170  is of such outer diameter so as to fit within the inner diameter of the external casing tube  180  and rotate and slide freely unless otherwise constrained. Extending along either side of the periphery of the head portion  171  are two longitudinal notches  172  and  172 ′. When the driving axial cylinder  170  is encased in the external casing tube  180  the two longitudinal notches  172  and  172 ′ are engaged by the corresponding internal ridges formed by the longitudinal depressions  184  and  184 ′ (not shown) in the external casing tube  180  such that the external casing tube  180  and the driving axial cylinder  170  are fixed against relative rotatable movement yet are free to axial movement. Axial movement of the driving axial cylinder  170  is limited by the aft end taper  182  of the external casing tube  180  and the aft portion  161  of the axially fixed driving casing tube  160 . The head portion of the driving axial cylinder  170  is also provided with internal threads  176  of such dimension so as to receive the external threads of the fore portion  192  of the pen refill gripper  190 . The body  174  of the driving axial cylinder  170  is of such outer diameter so as to fit within the inner diameter of the driving casing tube  160  and rotate and slide freely unless otherwise constrained. The body  174  of the driving axial cylinder  170  is provided with a radially outwardly directed stud  175  which is received by the sinuously curved slot  165  in the driving casing tube  160  when assembled.  
         [0041]    The external casing tube  180  is provided with two parallel longitudinally extending depressions  184  and  184 ′ (not shown) on either side of the outer periphery of its aft portion which form corresponding ridges on the inner surface of the external casing tube (not shown), and a depressed ring  183  around the external casing tube  180  in suitable position along the fore portion which forms a ridge on the internal surface of the external casing tube  180 . When the driving casing tube  160  is encased in the external casing tube  180 , the internal ridge corresponding to the suitably positioned depressed ring  183  of the external casing tube is engaged by the corresponding concave ring  163  in the driving casing tube such that the external casing tube  180  and the driving casing tube  160  are fixed against relative axial movement yet to be relatively rotatable. When the driving axial cylinder  170  is encased in the external casing tube  180  the two longitudinal notches  172  and  172 ′ are engaged by the corresponding longitudinal depressions  184  and  184 ′ (not shown) in the external casing tube  180  such that the external casing tube  180  and the driving axial cylinder  170  are fixed against relative rotatable movement yet are free to axial movement.  
         [0042]    The pen refill gripper  190  has a fore portion  192  provided with external threads, and a larger diameter aft portion  191  and is provided with a sinuous tunnel  193  that passes through the length of the pen refill gripper  190  starting near the center of the for portion  192  of the pen refill gripper  190  and finishing off center near the aft portion  191  of the pen refill gripper. The shape and internal dimension of the tunnel  193  is such that when the pen refill  130  is placed within the tunnel  193 , the nib  139  of the pen refill  130  aligns with the center of the pen refill gripper  190 , the shaft of the pen refill  130  is diverted off center, and relative motion of the pen refill  130  and the pen refill gripper  190  is limited by the enlargement  137  in the shaft of the pen refill  130 . Diversion of the shaft of the pen refill  130  off center ensures that the pen refill  130  will not interfere with the caliper arms  18  and  18 ′ when the twist actuated pen device  111  is assembled and the caliper device  20  is placed in its storage position within the hollow aft barrel  113 . The external threads of the fore portion  192  of the pen refill gripper  190  are matched to the internal threads  176  of the driving axial cylinder  170 .  
         [0043]    [0043]FIG. 10 demonstrates the partially assembled twist actuated pen device  111 . The pen tip  117  is fixably attached to the fore portion  162  of the driving casing tube. The body  174  of the driving axial cylinder  170  is placed within the driving casing tube  160  such that the projection  175  on the body  174  of the driving axial cylinder  170  is engaged by the slot  165  of the driving casing tube  160 . The assemblage of the driving axial cylinder  170  and the driving casing tube  160  is then placed into the external casing tube  180  and coupled thereto by engagement of the concave ring  163  and the matching ridge on the internal surface of the external casing tube  180  formed by the depressed ring  183  in the external casing tube  180  such that the driving casing tube  160  is rotatable relative to the external casing tube  180  but held against axial movement. The notches  172  and  172 ′ on the head  171  of the driving axial cylinder  170  align with matching ridges on the inner surface of the external casing tube  180  that are formed by the corresponding longitudinal depressions  184  and  184 ′ (not shown) in the external casing tube  180  such that the driving axial cylinder is free to axial movement relative to external casing tube  180  but is not rotatable relative to external casing tube  180 . Thus assembled, rotation of the pen tip  117  relative to the external casing tube  180  causes rotation of the driving casing tube  160  with resultant axial displacement of the driving axial cylinder  170  by the movement of the slot  165  of the driving casing tube  160  past the projection  175  of the driving axial cylinder  170 .  
         [0044]    The pen refill  130  is aligned with and inserted into the tunnel  193  of the of the pen refill gripper  190  until the enlargement  137  in the pen refill limits further insertion. Thus, the nib  139  of the pen refill  130  aligns with the center of the pen refill gripper  190 , the shaft of the pen refill  130  is diverted off center, and further insertion of the pen refill  130  and the pen refill gripper  190  is limited by the enlargement  137  in the shaft of the pen refill  130 .  
         [0045]    When assembled, rotation of the pen tip  117  is coupled to rotation of the driving casing tube  160  which produces movement of the sinuously curved slot  165  of the driving casing tube  160  past the projection  175  of the driving axial cylinder  170 . With the driving axial cylinder  170  fixed against relative rotation by the interaction of the notches  172  and  172 ′ on the head  171  of the driving axial cylinder  170  with the matching ridges on the inner surface of the external casing tube  180  formed by the corresponding longitudinal depressions  184  and  184 ′ (not shown) in the external casing tube  180 , the movement of the sinuously curved slot  165  past the projection  175  of the driving axial cylinder  170  causes axial movement of the driving axial cylinder  170  and with it the pen refill  136  between an extended position of FIG. 11 in which the and the retracted position of FIG. 12. When in the extended position shown in FIG. 11, the projection  175  of the driving axial cylinder  170  is located it the fore most terminal portion  166  of the sinuously curved slot  165  with the pen nib  139  of the pen refill  130  held in an extended position convenient for writing. When in the retracted position shown in FIG. 12, the projection  175  of the driving axial cylinder  170  is located in the aft most terminal portion  166  of the sinuously curved slot  165  with the pen nib  139  of the pen refill  130  held in a retracted position convenient for carrying the twist actuated pen device  111 .  
       Other Possible Uses and Variations  
       [0046]    While the invention has been described with reference to several particular embodiments thereof those skilled in the art will be able to make various modifications to the described embodiments of the invention without departing from the true spirit and scope of the invention. It is intended that all combinations of elements and steps that perform substantially the same function to achieve substantially the same result are within the scope of the invention. The first embodiment described herein is a non-retractable pen with a separate caliper stored with in the confines of the hollow pen barrel and with a cap over the pen tip that can be removed and placed over the caliper in order to deploy the pen device as a writing instrument. The second embodiment described herein is a pen with a retractable with a separate caliper stored with in the confines of the hollow pen barrel in which the pen nib can be exposed for writing or retracted for storage by twisting the pen tip relative to the pen barrel. However, it should be understood that the two foregoing ballpoint pen arrangements are just exemplary. Various mechanisms for advancing and retracting the ballpoint cartridge tip could also be used. The arrangement of the caliper device in relationship to the pen refill could also be altered. In a previously non-disclosed embodiment of the invention, the pen refill extended down the center of the pen barrel and the legs of the caliper rested on either side of the pen refill when the caliper was placed in its storage location. The components of the pen device as well as the components of the caliper-device could be composed of any suitable material, including but not limited to aluminum alloys, copper alloys, ferrous alloys, plastics, or ceramics.