DUAL PURPOSE PEN CAPPING SYSTEM FOR PEN PLOTTERS

Abstract: A pen cap raising and lowering mechanism (20) for use in a pen plotter having a pen station for holding a pen (10) prior to use and a pen cap raising and lowering mechanism (20) for capping and uncapping a writing tip of the pen to allow a shipping cap (12) of a pen (10) to be employed within the pen plotter to cap and uncap the pen (10). There is pen cap raising and lowering apparatus carried by the pen plotter moving between a raised position and a lowered position to cap and uncap, respectively, a pen (10) operably located at the pen station. There are also gripping fingers (22) carried by the pen cap raising and lowering apparatus (20) for positioning, gripping and holding a shipping cap of a pen (10) when the pen (10) is initially inserted into the pen station and during use of the pen (10) and for releasing the shipping cap (12) in combination with the pen (10) when the pen is removed from the pen station for replacement. The pen cap raising and lowering apparatus (20) retains the gripping fingers (22) in the raised position when a pen (10) is initially inserted into the pen station and when the pen (10) is removed from the pen station for replacement. There is an adaptor cap (26) for using pens not provided with the shipping cap as well as an optional vent seal (38) to seal the pen against temperature and pressure change effects.

Description: DUAL PURPOSE PEN CAPPING SYSTEM FOR PEN PLOTTERS Background of the Invention: The present invention relates to pen plotters and, more particularly, to a pen cap raising and lowering mechanism for use in a pen plotter having a pen station for holding a pen prior to use and a pen cap raising and lowering mechanism for capping and uncapping a writing tip of the pen to allow a shipping cap of a pen to be employed within the pen plotter to cap and uncap the pen comprising, pen cap raising and lowering apparatus carried by the pen plotter moving between a raised position and a lowered position to cap and uncap, respectively, a pen operably located at the pen station; and, gripping fingers carried by the pen cap raising and lowering apparatus for positioning, gripping and holding a shipping cap of a pen when the pen is initially inserted into the pen station and during use of the pen and for releasing the shipping cap in combination with the pen when the pen is removed from the pen station for replacement; wherein, the pen cap raising and lowering apparatus retains the gripping fingers in the raised position when a pen is initially inserted into the pen station and when the pen is removed from the pen station for replacement. As depicted in Figures 1 through 4, in a typical prior art pen plotter, a pen 10 comes with a shipping cap 12 disposed over the drawing tip 14. As depicted in Figure 2, the shipping cap 12 is typically discarded and the pen 10 is mounted over a capping mechanism 16 which is part of the pen plotter. The capping mechanism 16 can be located at a pen station or on a turret holding multiple pens. When not in use, the pen 10 is positioned as shown in Figure 3 with the capping mechanism 16 protecting the drawing tip 14 of the pen 10. When the pen is to be used, as shown in Figure 4, the capping mechanism 16 is lowered so that the drawing tip 14 will clear the capping mechanism 16 as the pen 10 is moved in the direction of the arrow 18 to a point of use on the pen plotter. Such integral pen-capping systems can be seen as for example in Patent 4,660,054 of Kajikawa, et al., 4,683,476 of Ferrari, et al. , 4,716,420 of Glassett and 4,982,208 of Farlotti. As the ink within the pen 10 is consumed, the pen 10 is discarded and a new pen 10 is positioned in the pen plotter to take its place. Unfortunately, the capping mechanism 16 is not replaced. Neither is there typically a procedure for cleaning the capping mechanism 16. Thus, over time, ink residue and airborne particles of dust, hair, and the like, accumulate within the area of the capping mechanism which covers the drawing tip 14. This can clog the tip or, occasionally thereafter, such debris can be picked up and carried by the drawing tip 14 to the plotting area where it can cause smearing and other undesirable effects on the plot itself. Wherefore, it is the object of this invention to provide a pen plotter in which the shipping cap with which a pen is sold and. delivered becomes part of the capping mechanism of the pen plotter itself so as to be replaced each time a pen is replaced. Other objects and benefits of the invention will become apparent from the detailed description which follows hereinafter when taken in conjunction with the drawing figures which accompany it. Summary; The foregoing object has been achieved in a pen plotter having a pen station for holding a pen prior to use and a pen capping and uncapping mechanism for capping and uncapping a writing tip of the pen, by the improvement of the present invention comprising, first gripping means associated with a shipping cap of a pen; and, second gripping means carried by the pen capping and uncapping mechanism for interacting with the first gripping means to position, grip and hold the shipping cap when a pen is initially inserted into the pen station and during use of the pen and to release the shipping cap in combination with the pen when the pen is removed from the pen station for replacement. In the preferred embodiment, the first gripping means comprises a circumferential groove in an outer surface of the shipping cap; and, the second gripping means comprises gripping fingers carried by the pen capping and uncapping mechanism sized to fit within the groove and grip the shipping cap. Also in the preferred embodiment, the pen capping and uncapping mechanism moves between a raised position and a lowered position to cap and uncap, respectively, a pen operably located at the pen station; and, the pen capping and uncapping mechanism retains the second gripping means in the raised position when a pen is initially inserted into the pen station and when the pen is removed from the pen station for replacement. As an additional feature, there is an adaptor cap sized substantially the same as a shipping cap and having the first gripping means as part thereof for interacting with the second gripping means to position and hold the adaptor cap in the position of a shipping cap on the pen capping and uncapping mechanism, whereby a pen not having a shipping cap can be employed in the pen plotter. In another aspect of the invention, the pen has a circumferential shoulder and a vent hole disposed within a portion of the pen bounded by the circumferential shoulder and the shipping cap has sealing means disposed along a top edge for engaging the shoulder to seal the vent hole from atmosphere when the shipping cap is in a capping position on the pen. Preferably, the sealing means is an elastomeric material which can comprise, for example, an O-ring disposed along the top edge in abutment with the shoulder when the shipping cap is in the capping position. Description of the Drawings: Figure 1 is a partially cutaway drawing of a prior art pen with its pen cap in place. Figure 2 is a drawing of the pen of Figure 1 with the cap removed. Figure 3 is a drawing depicting a prior art pen-capping system with the capping mechanism in place over the drawing tip of the associated pen. Figure 4 is a drawing showing the pen-capping mechanism of Figure 3 lowered to allow the pen to be moved to a point of use. Figure 5 is a partially cutaway drawing showing the pen-capping approach of the present invention with the pen cap in place protecting the pen drawing tip. Figure 6 is a drawing in the manner of Figure 4 showing the pen-capping system of the present invention lowered to allow the pen to move to its point of use. Figure 7 is a partially cutaway enlarged view of the pen-capping system of the present invention. Figure 8 a cutaway view through an adapting cap to be employed with the system of the present invention with pens not having a shipping cap intended for use with the system. Figure 9 is a simplified partially cutaway drawing of a prior art plotter drawing pen of one type showing a typical positioning of a vent hole therein. Figure 10 is a simplified partially cutaway drawing of a prior art plotter drawing pen of another type showing two possible vent hole positions therein. Figure 11 is a cutaway drawing of a pen cap according to the present invention adapted for use in sealing the vent holes on a pen of the type in Figure 10 when employing a liquid ink tip. Figure 12 is a cutaway drawing of a pen cap according to the present invention adapted for use in sealing the vent holes on a pen of the type in Figure 10 when employing a roller ball or fiber tip. Description of the Preferred Embodiment: The concept of maintaining the shipping cap 12 with which a plotter pen 10 is shipped within the plotter itself is not new per se. In patent number 4,920,357 of Johnson, a supply of plotter pens is maintained off-line to the turret holding the pens actually being used by the plotter. When a pen in the turret runs low on ink and is to be replaced, the replacement process is automatic. A new pen is removed from the off-line storage and moved to the turret to replace the old pen. In the path between the off-line storage and the turret, the pen moves over an uncapping mechanism which removes and discards the shipping cap. Thereafter, the tip of the pen is covered and protected by an integral capping mechanism as in the other prior art systems as mentioned above. By contrast, the dual-purpose pen capping system of this invention now to be described in detail does not discard the shipping cap. Rather, the shipping cap is employed to cap and uncap the pen during use and is then discarded along with the pen when the ink in the pen is consumed. The dual-purpose pen-capping system of the present invention in its preferred embodiment is shown in Figures 5-7. In the prior art system of Figures 3 and 4, the capping mechanism 16 is attached to and carried by a raising-and-lowering mechanism 20. In the present invention, the raising-and-lowering mechanism 20 is provided with a pair of gripping fingers 22 and the shipping cap 12' is provided with a groove 24 into which the gripping fingers 22 fit when the pen 10 is inserted into its holding station (not shown) on the pen plotter at a holding point or as part of a turret. Thus, the gripping fingers 22 and the groove 24 cooperate to both position and hold the shipping cap 12 ' on the raising-and-lowering mechanism 20. In this regard, as those skilled in the art will readily recognize and appreciate, the raising-and-lowering mechanism 20 and its operating apparatus and controls must be changed when accomplishing the objectives of the present invention. In the prior art approach of Figure 3, the capping mechanism 16 surrounds the drawing tip 14 such that the capping mechanism 16 must be lowered in order for the pen 10 to be placed into the station or to be removed therefrom. By contrast, the raising-and-lowering mechanism 20 of a pen plotter incorporating the present invention must operate in two modes. When a pen 10 is being inserted initially into the station (i.e. to engage the cap with the gripping fingers 22) , the raising and lowering mechanism 20 must not lower the gripping fingers 22 from their raised (i.e. "capped") position so that the shipping cap 12' attached to the pen 10 will move into proper position along with the pen 10 to be gripped by the gripping fingers 22. Thereafter, as the pen 10 is used, the raising-and-lowering mechanism 20 is activated to raise and lower the shipping cap 12' in the usual manner to cap and uncap the drawing tip 14 employing the shipping cap 12' . Thus, a pen 10 is initially inserted into the pen plotter and finally removed therefrom for replacement with the gripping fingers 22 in their raised position as depicted in Figure 5. Between insertion and replacement of the pen 10, the gripping fingers 22 are lowered in combination with the shipping cap 12' as depicted in Figure 6 so that the pen 10 can be moved off-station to a point of use. Thus, when the ink within the pen 10 is consumed and the pen 10 is finally replaced, the shipping cap 12' is replaced along with it. As a consequence, each pen 10 is capped and uncapped with a clean cap in the form of its own shipping cap 12' and the problems of accumulated debris within the capping portion that contacts the drawing tip 14 is eliminated. Once a pen plotter has been adapted to operate according to the present invention, as those skilled in the art will readily recognize and appreciate, a conventional pen 10 with shipping cap 12 cannot be employed. To make provision for such eventuality, the adaptor cap 26 of Figure 8 can be employed. The adaptor cap 26 is substantially the same size and shape as a shipping cap 12' and includes the groove 24 for the gripping fingers 22. To use a standard pen not having an appropriate shipping cap 12', the adaptor cap 26 is inserted into the gripping fingers 22. Subsequently, as a pen 10 without its standard shipping cap 12 is initially inserted into the pen plotter or removed therefrom for replacement, the adaptor cap 26 is raised and lowered for pen operation in the normal manner as described above and as depicted in Figure 6. Another benefit of the foregoing pen-capping system in general is the ability to completely seal pens in use so as to make them insensitive to temperature and pressure changes as well as protecting the tips from contamination. This can best be understood with reference first to Figures 9 and 10. As those skilled in the pen art are aware, in order for a liquid ink to flow from the tip without potential problems, the interior of a pen must be vented to the atmosphere. In Figure 9, a one-piece pen 10 is depicted having a drawing tip 14 with a drawing medium 28 extending therefrom. The drawing medium 28 can comprise a liquid ink tip, a roller ball, or a fiber/ceramic tip, for example. In such a configuration, the vent hole 30 can be located alongside the drawing medium 28, as depicted in Figure 9. A two-piece pen 10" is shown in Figure 10 as comprising a cylindrical inner portion 32 carrying the drawing tip 14 with drawing medium 28 extending therefrom and a cylindrical outer portion 34 shaped to be gripped by pen-handling mechanisms of the pen plotter with which it is associated. In such a configuration, the vent hole 30 can be located, for example, alongside the drawing medium 28 or between the inner and outer portions 32, 34, as depicted in Figure 10. As those skilled in the art are well aware and appreciate, the vent hole can be placed in numerous locations. Wherever the vent hole is placed, however, the pen 10', 10" typically has a shoulder 36 adjacent the outer periphery. As depicted in Figures 11 and 12, an elastomeric seal such as a sealing 0-ring 38, or the like, can be positioned in the top edge 40 of the shipping cap 12' to be used with the present invention and, thereby, an effective seal of any vent location within the location of the elastomeric seal is accomplished. Actually, the elastomeric sealing O-ring 38 seals both the vent and the tip and creates a closed system. Thus, an increase in temperature and/or reduction in external pressure will cause an internal pressure force on the sealing O-ring 38. The capping force holding the sealing O-ring 38 against the shoulder 36 must, therefore, be sufficient to overcome any anticipated force. This force is easily calculated according to principals of physics employing techniques well known to those skilled in the art and will not be developed in an detail herein in the interest of simplicity and the avoidance of redundancy. Whether or not the above-described sealing O-ring 38 is incorporated into the shipping cap 12', the sizing of the shipping cap 12' should be done with care. In the case of the use of a liquid ink tip or ceramic tip as the drawing medium 28 as depicted in Figure 11, the distance from the shoulder 36 to the end of the liquid ink tip or ceramic tip, "d", must be the same in the shipping cap 12 between the top of the sealing O-ring 38 and the tip-sealing ball 42 that is typically put in the bottom of a cap 12 (and, therefore, employed in the shipping cap 12' as well) . In the case of the use of a fiber tip or roller ball as the drawing medium 28 as depicted in Figure 12, the distance between the top of the sealing O-ring 38 and the inner bottom of the shipping cap 12' must be greater than the distance, "d ιr from the shoulder 36 to the end of the fiber tip or roller ball so that the fiber tip or roller ball does not touch the inner bottom of the shipping cap 12'. Wherefore, having thus described the present invention, what is claimed is:

Claims: 1. In a pen plotter having a pen station for holding a pen prior to use and a pen capping and uncapping mechanism for capping and uncapping a writing tip of the pen, the improvement comprising: a) first gripping means associated with a shipping cap of a pen; and, b) second gripping means carried by the pen capping and uncapping mechanism for interacting with said first gripping means to position, grip and hold said shipping cap when a pen is initially inserted into the pen station and during use of the pen and to release said shipping cap in combination with said pen when said pen is removed from the pen station for replacement. 2. The improvement to a pen plotter of claim 1 wherein: a) said first gripping means comprises a circumferential groove in an outer surface of said shipping cap; and, b) said second gripping means comprises gripping fingers carried by the pen capping and uncapping mechanism sized to fit within said groove and grip said shipping cap. 3. The improvement to a pen plotter of claim 1 wherein additionally: a) the pen capping and uncapping mechanism moves between a raised position and a lowered position to cap and uncap, respectively, a pen operably located at the pen station; and, b) the pen capping and uncapping mechanism retains said second gripping means in said raised position when a pen is initially inserted into the pen station and when said pen is removed from the pen station for replacement. 4. The improvement to a pen plotter of claim 3 and additionally comprising: an adaptor cap sized substantially the same as a said shipping cap and having a said first gripping means as part thereof for interacting with said second gripping means to position and hold said adaptor cap in a position of a said shipping cap on the pen capping and uncapping mechanism whereby a pen not having a said shipping cap can be employed in the pen plotter. 5. The improvement to a pen plotter of claim 1 wherein: a) said pen has a circumferential shoulder and a vent hole disposed within a portion of said pen bounded by said circumferential shoulder; and, b) said shipping cap has sealing means disposed along a top edge for engaging said shoulder to seal said vent hole from atmosphere when said shipping cap is in a capping position on said pen. 6. The improvement to a pen plotter of claim 5 wherein: said sealing means comprises an elastomeric seal disposed along said top edge in abutment with said shoulder when said shipping cap is in said capping position. 7. In a pen plotter having a pen station for holding a pen prior to use and a pen capping and uncapping mechanism for capping and uncapping a writing tip of the pen, the method of using a shipping cap associated with a pen to cap and uncap the pen during use in the pen plotter comprising the steps of: a) gripping and holding the shipping cap with the pen capping and uncapping mechanism when a pen is initially inserted into the pen station; b) capping and uncapping the pen with the shipping cap employing the pen capping and uncapping mechanism during use of the pen in the pen plotter; and, c) releasing the shipping cap in combination with the pen when the pen is removed from the pen station for replacement. 8. In a pen plotter having a pen station for holding a pen prior to use and a pen capping and uncapping mechanism for capping and uncapping a writing tip of the pen, an improved pen capping and uncapping mechanism comprising: gripping fingers carried by the pen capping and uncapping mechanism for positioning, gripping and holding a shipping cap of a pen when said pen is initially inserted into the pen station and during use of the pen and for releasing said shipping cap in combination with said pen when said pen is removed from the pen station for replacement. 9. The improved pen capping and uncapping mechanism for a pen plotter of claim 8 wherein: a) said shipping cap has a circumferential groove in an outer surface thereof; and, b) said gripping fingers carried by the pen capping and uncapping mechanism are sized to fit within said groove and grip said shipping cap. 10. The improved pen capping and uncapping mechanism for a pen plotter of claim 9 wherein additionally: a) the pen capping and uncapping mechanism moves between a raised position and a lowered position to cap and uncap, respectively, a pen operably located at the pen station; and, b) the pen capping and uncapping mechanism retains said gripping fingers in said raised position when a pen is initially inserted into the pen station and when said pen is removed from the pen station for replacement. 11. The improved pen capping and uncapping mechanism for a pen plotter of claim 10 and additionally comprising: an adaptor cap sized substantially the same as a said shipping cap and having a said groove as part thereof for interacting with said gripping fingers to position and hold said adaptor cap in a position of a said shipping cap on the pen capping and uncapping mechanism whereby a pen not having a said shipping cap can be employed in a pen plotter employing the improved pen capping and uncapping mechanism. 12. The improved pen capping and uncapping mechanism for a pen plotter of claim 8 wherein: a) said pen has a circumferential shoulder and a vent hole disposed within a portion of said pen bounded by said circumferential shoulder; and, b) said shipping cap has sealing means disposed along a top edge for engaging said shoulder to seal said vent hole from atmosphere when said shipping cap is in a capping position on said pen. 13. The improved pen capping and uncapping mechanism for a pen plotter of claim 12 wherein: said sealing means comprises an elastomeric seal disposed along said top edge in abutment with said shoulder when said shipping cap is in said capping position. 14. A pen cap raising and lowering mechanism for use in a pen plotter having a pen station for holding a pen prior to use and a pen cap raising and lowering mechanism for capping and uncapping a writing tip of the pen to allow a shipping cap of a pen to be employed within the pen plotter to cap and uncap the pen comprising: a) pen cap raising and lowering apparatus carried by the pen plotter moving between a raised position and a lowered position to cap and uncap, respectively, a pen operably located at the pen station; and, b) gripping fingers carried by said pen cap raising and lowering apparatus for positioning, gripping and holding a shipping cap of a pen when said pen is initially inserted into the pen station and during use of the pen and for releasing said shipping cap in combination with said pen when said pen is removed from the pen station for replacement; wherein, c) said pen cap raising and lowering apparatus retains said gripping fingers in said raised position when a pen is initially inserted into the pen station and when said pen is removed from the pen station for replacement. 15. The pen cap raising and lowering mechanism for a pen plotter of claim 14 wherein: a) the shipping cap has a circumferential groove in an outer surface thereof; and, b) said gripping fingers are sized to fit within said groove and grip said shipping cap. 16. The pen cap raising and lowering mechanism for a pen plotter of claim 15 and additionally comprising: an adaptor cap sized substantially the same as a said shipping cap and having a said groove as part thereof for interacting with said gripping fingers to position and hold said adaptor cap in a position of a said shipping cap on said pen cap raising and lowering apparatus whereby a pen not having a said shipping cap can be employed in a pen plotter employing the improved pen cap raising and lowering mechanism. 17. The pen cap raising and lowering mechanism for a pen plotter of claim 14 wherein: a) said pen has a circumferential shoulder and a vent hole disposed within a portion of said pen bounded by said circumferential shoulder; and, b) said shipping cap has sealing means disposed along a top edge for engaging said shoulder to seal said vent hole from atmosphere when said shipping cap is in a capping position on said pen. 18. The improved pen capping and uncapping mechanism for a pen plotter of claim 17 wherein: said sealing means comprises an elastomeric seal disposed along said top edge in abutment with said shoulder when said shipping cap is in said capping position.

Inventors: BERTALAN JOHN M, NGUYEN PATRICK, OSTERMEIER BRUCE H, PRESTON BRIAN C, BERTALAN, JOHN, M., NGUYEN, PATRICK, OSTERMEIER, BRUCE, H., PRESTON, BRIAN, C.
Applicants: CALCOMP INC, CALCOMP INC.
Application year: 1992
Main classification: B41J2
IPC codes: B43L13, G01D15