US 3308501 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
March 14, 1967 MARSH 3,308,501
MARKING PEN Filed Sept. 17, 1964 GERALD G MARSH llVl/EA/TOH BY BUCKHOR/V, 5L ORE, K LAROU/S T 8 SPAR/(MAN ATTORNEYS Patented Mar. 14, 1967 3,308,501 MARKING PEN Gerald G. Marsh, Portland, reg., assignor to Joyce G. Marsh, Portland, Oreg. Filed Sept. 17, 1964, Ser. No. 397,191 2 Claims. (Cl. 15-563) The present invention relates to a marking pen and more particularly to a pen having a felt writing point for marking on paper and other surfaces with an oilor water-base ink.
Pens of the above type are commonly used for marking routes on road maps and for bold line drawing, writing, marking of packages and numerous other uses. Many varieties of this type of pen have been used in the past, but none have proved entirely satisfactory. The simplest variety comprises merely a felt wick saturated with ink and sealed in a handle of the pen so that when the supply of ink in the wick is either used up or dries up, the pen is discarded.
Another variety includes a flexible squeeze bottle which contains a supply of ink and a short length of writing felt which becomes immersed in the ink when the bottle is turned upsidedown. The amount of ink transmitted through the wick, and therefore the heaviness of the mark made by the point of the wick, is controlled by squeezing the bottle. Thus the width of the line made by the point of the felt is diflicult to control and varies when drawing a line.
Another variety has a valve between an ink supply and a felt writing wick, with the valve being actuated by depressing the point of the wick to permit ink to saturate the wick. Each time the wick needs resoaking, the marking operation must be interrupted and the point depressed on a blotting pad, for otherwise a large blot would be formed on the surface being marked.
All of the prior varieties of felt pens have further disadvantages in having relatively short wicks with low ink capacities, wicks which tend to dry up when not in use, and nonreplenishable ink supplies.
Accordingly, a primary object of the present invention is to provide a new and improved marking pen which overcomes the above disadvantages of prior art pens.
More specifically, an object of the invention is to provide a felt-type marking pen which can be used for long periods of time with a single filling of ink and with a single wick.
Another object is to provide such a pen having a refillable ink reservoir and a replaceable wick.
Another object is to provide a marking pen which provides a constant, uninterrupted flow of ink to the writing end of the wick.
Still another object is to provide a marking pen having a felt point that can be left uncapped without drying out when not in use.
A further object is to provide a marking pen wherein the rate of flow of ink to the writing end of the wick can be selectively controlled and varied as desired.
A still further object of the invention is to provide a marking pen that will not leak ink.
In furtherance of the above objects, an illustrated embodiment of the invention includes a tubular body for retaining ink having a removable filler cap closing one end of the body and a marking head portion at the other end thereof. A bore extends axially through the head portion into communication with the interior of the body, and a felt writing wick extends through the bore and into the interior of the body, preferably terminating near the filler cap-end of the body. The writing end of the wick projects from the head, and the Wick can be drawn through the bore as desired when the writing end of the wick becomes worn down. The body is filled with ink to a level such that at least a portion of the wick within the body is immersed in the ink in any position of the pen. Excess flow of ink and leakage through the head is prevented by the wick, which completely fills the bore, and also by regulating the air pressure within the body by a threaded adjustment of the filler cap.
The above and other objects will become more apparent from the following description and the accompanying drawing wherein:
FIG. 1 is an axial sectional view through the pen showing the internal construction thereof;
FIG. 2 is a bottom end view of the pen of FIG. 1;
FIG. 3 is a fragmentary view showing the head end of the pen and a closure cap, shown in section, for the head; and
FIG. 4 is a view of the pen in a horizontal disposition with a portion of the body cut away to illustrated that the wick remains in contact with the fluid regardless of the orientation of the pen.
With reference to the drawings, the illustrated pen includes an elongate, hollow, cylindrical body portion 10 which serves as a reservoir for a supply of ink, or writing fluid, 12. The body is closed at one end by a removable filler cap 14, and a marking head 16 is provided at the opposite end thereof. The body is preferably made of a translucent or transparent plastic material so that the level of Writing fluid and length of wick therewithin can be observed without removing the filler cap.
The head includes a cylindrical base portion 13 joined to the one end of the reservoir and a frustoconical point, or tip portion, 29 extending axially outwardly from the base portion. The head is provided with an axial bore 22 extending from the outer end of the tip portion 20 into communication with the interior of the reservoir. A relatively long wick 24 of relatively stiff felt or feit-like material extends through the bore and into the reservoir, terminating, when new :at least, at its inner end 26 adjacent the filler cap 14 and terminating at the opposite, marking end a short distance outwardly of the tip portion 20 to provide a blunt writing point 28.
It is important that the cross-sectional area of the wick be such that the wick completely and snugly fills the bore 22 to prevent the free flow of excess fluid out of i the body through the bore when the marking tip of the pen is pointed downwardly in marking position.
It will be observed that when the reservoir 10 is filled to any substantial level with a marking fluid 12 and the wick extends through a major portion of the length of the interior of the body, the wick will be immersed in the fluid regardless of the orientation of the pen. For example, in FIG. 4 the pen is shown in a horizontal position with reservoir only half filled with ink and yet the wick remains immersed. This feature prevents the wick from drying out :and provides the writing tip 28 of the wick with a ready supply of fluid instantly available when the tip is applied to a surface to be marked.
Means are provided to enable drawing of the wick outwardly through the bore 22 to expose additional wick material for marking when the previously exposed end of the wick becomes worn away in use, and yet to prevent the exposed end of the wick from being pushed into the bore when writing pressure is applied to the exposed wick end 28. For this purpose, the outer end portion 30 of the bore 22 is formed having a diameter slightly less than that of the remainder of the bore as shown in FIG. 1, and the tapered tip portion 20 of the head is provided with at least two axially extending slots 32 spaced circumferentially thereof as shown in FIG. 3. Thus the tip portion has a certain amount of flexibility, and normally has a pinching effect on the wick to prevent it from being pushed inwardly through the bore by normal writing pressures. However, the slight flexibility provided by the slots enables the bore to expand slightly so that the wick can be drawn outwardly. When the wick becomes so short that it cannot be kept immersed in ink within the body, the wick should be replaced by pulling it from the bore and inserting a new one.
When the supply of in 12 within the body becomes so low as to no longer submerge any portion of the wick, as observed through the transparent or translucent sidewall of the body, the body should be refilled. This is one by turning the pen upsidedown from its FIG. 1 position and removing the tiller cap 14 so that ink can be poured into the body through the open end thereof. Either an oil-base or a waterabase ink can be used in the pen, and undoubtedly other inks would work equally well.
The filler cap 14 includes an externally threaded cylindrical plug portion 34 which screws into an internally threaded inner sidewall portion as of the body adjacent the lower, filler cap-end 38 of the latter. A flange portion 40 of the filler cap is of slightly larger diameter than the plug portion so as to engage and thus seal the end wall 38 of the body when the plug portion is fully threaded into the sidewall 36 of the body. A head portion 42 having a slotted driving recess 44 extends axially fromthe outer surface of the flange portion 40 of the filler cap. Thus the cap can be threaded on or unthreaded from the body by inserting a screw driver blade, coin, or similar thin-walled instrument into the recess and rotating the same.
A filler cap of the foregoing threaded construction is advantageous in that is provides a means for controlling the rate of flow of ink from the writing tip 28 of the wick when the tip is pointed in a downward direction. It has been found that by tightening the cap 14 fully against the end wall 38 of the body, the interior of the body is both air and liquid tight at the cap end so that ink is transmitted through the wick to the tip 28 at a minimum rate, thus producing a very light, thin line on a surface to be marked. If desired, an O-ring seal could be inserted between the flange and the end wall to prevent any possibility of fluid leakage during, for example, shipment. However, by counter-rotating the cap just enough to break the air seal but not enough to permit ink to leak out of the body through the cap end, that is, just a small fraction of a turn, the air pressure within the interior of the body can be selectively increased to such an extent that ink will flow from the body of the end 28 of the wick at a constant rate to preduce a line of a uniform desired width on the surface to be marked. The user is thus able to adjust the rate of flow of ink to the writing end of the wick to suit his particular needs by a threaded adjustment of the cap. This feature overcomes a disadvantage found in most prior art pens wherein there is either no provision for selectively increasing or decreasing air pressure within the pen so that ink flow cannot be cont-rolled, or wherein flow is controlled by squeezing flexible sidewalls of the pen, the latter variety of pen invariably resulting in an uneven rate of flow of ink.
As shown in FIG. 3, a closure cap 46 is provided for enclosing the head end of the pen when the pen is not in use, although the wick will not dry out if not capped because the inner portion of the wick is always immersed in the ink supply. The cap has an opening just large enough so that the cap can he slipped over the base portion 18 of the head and held in place by a friction fit between the cap and base portion,
Having illustrated and described a preferred embodiment of my invention, it should be apparent to those skilled in the art that the invention permits of modification in arrangement and detail. I claim as my invention all such modifications as come within the true spirit and scope of the appended claims.
1. A markiu g pen comprising:
a one-piece body and tip,
said body being hollow to define a fluid ink reservoir and open at one end thereof,
said tip forming a continuation of the opposite end of said body and being solid so as to close said opposite end,
said tip having an axial bore extending therethrough into communication with said reservoir,
said tip and body being-formed of relatively rigid material so that said reservoir has a constant volume,
a compressible wick of only one thickness extending through said bore and, at least initially, throughout substantially the entire length of said reservoir so that said wick is immersed in ink within said reservoir in all positions of said pen,
said wick having the same cross sectional shape as said bore, completely filling said bore and being under compression therewithin so as to prevent leakage of liquid from said reservoir through said bore when disposed with said tip in writing position,
an outer portion of said bore being necked in so as to have a normal diameter less than that of the remainder of said bore and less than the diameter of said wick and so as to have a pinching effect on said wick,
said tip being tapered toward its outer extremity so as to progressively reduce the thickness of the walls thereof defining said outer bore portion and thereby progressively increase the flexibility of said walls in the same direction,
the outer extremity of said tip being axially slotted to form resilient fingers biased inwardly of the remainder of said bore and which press into said wick to prevent the pushing of said wick inwardly of said bore, but which permit the drawing of said wick outwardly of said bore, said slots extending laterally inwardly of said tip to said bore but having a length less than the length of said bore so that said slots are cut ofl from direct communication with said reservoir by said wick,
said open end of said body being closed by a filler and flow control cap including a cylindrical and externally threaded plug portion extending into said open end and mating with complementary internal threads on the inner wall of said body and a flange portion engaging an end wall portion of said body at said open end when said plug portion is fully threaded into said body,
said cap including said flange and plug portions being made of a single solid piece of material,
and means for threading and unthreading said plug portion from said body so as to regulate the bleeding of air into the interior of said body between said flange and plug portions and between the mating threads of said plug and said body thereby to control the flow of fluid through said wick to the writing tip thereof.
2. A marking pen according to claim 1 wherein said tip, body and cap are all made of the same kind of rigid plastic material.
References Cited by the Examiner UNITED STATES PATENTS 426,622 4/1890 Madden 15-561 576,629 2/1897 Taylor 120-21 1,545,656 7/1925 Hothers all 15-563 Keeshan 15563 X Deli 120-18 Schreyer 15-563 Duncan 15-563 Cline 15-563 CHARLES A. WILLMUTH, Primary Examiner. S. E. BECK, Assistant Examiner.