US 3917418 A
A resilient bushing for imparting a frictional drag to a rotating collar, such as the drive collar of a writing instrument, the rotation of which causes a writing cartridge to propel or repel, said bushing comprising a cylindrical, open-ended body having an open portion in its cylindrical wall permitting axial compression of the bushing to impart a resilient bearing thrust against the rotating collar.
Claims available in
Description (OCR text may contain errors)
United States Patent [1 1 Lanoie 1 Nov. 4, 1975 RESILIENT BUSHING FOR WRITING INSTRUMENTS AND THE LIKE Inventor: Louis A. Lanoie, East Greenwich,
Assignee: Garland Industries, Inc., Coventry,
Filed: Jan. 20, 1975 Appl. No.: 542,414
U.S. Cl 401/116; 401/78 Int. Cl. B43K 24/06 Field of Search 401/116, 75, 77, 78, 175,
References Cited UNITED STATES PATENTS Lanoie 401/i 16 3,630,629 12/1971 Spirito 401/116 Primary Examiner-Lawrence Charles Attorney, Agent, or Fifm-Salter & Michaelson A resilient bushing for imparting a frictional drag to a rotating collar, such as the drive collar of a writing instrument, the rotation of which causes a writing cartridge to propel or repel, said bushing comprising a cylindrical, open-ended body having an open portion in its cylindrical wall permitting axial compression of the bushing to impart a resilient bearing thrust against the rotating collar.
ABSTRACT 5 Claims, 4 Drawing Figures U.S. Patant Nov. 4, 1975 RESILIENT BUSHING FOR WRITING INSTRUMENTS AND THE LIKE BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to a resilient bushing having particular utility, although not limited thereto, in connection with writing instruments of the retractable type, such as, for example, the type of retractable writing instrument shown in U.S. Pat. No. 3,436,160, issued Apr. 1, 1969.
In retractable writing instruments of the type shown in above-mentioned U.S. Pat. No. 3,436,160, a spiral collar is rotatably mounted over a fixed cylindrical stem member, said stern member having a longitudinally extending slot therein. A carrier member is freely positioned within the stem member, said carrier member having a lug extending through the stem slot and making driving engagement with the spiral collar, whereby rotation of the latter causes rectilinear motion of the carrier to propel or repel a writing cartridge connected thereto. In order to impart a smooth tension or frictional drag to rotation of the spiral collar, the usual means is to have means on the stem member exerting a resilient thrust against one end of the collar with means at the opposite end of the collar resisting said thrust, whereby a frictional drag is imparted to rotary movement of the collar. The usual way of imparting this resilient thrust is to utilize a resilient washer, such as the washer shown at 54 in aforesaid U.S. Pat. No. 3,436,160. It has been found, however, that resilient washers of this type are not completely satisfactory because they afford only a very limited degree of resilience and because the resilient bearing imparted thereby is not a smooth, uniform one.
It is therefore a primary object of this invention to provide a resilient bushing capable of providing a smooth, uniform resilient bearing action against the end of a rotating member, such as the rotating drive collar of a retractable writing instrument, although not limited to this specific use.
Another object is the provision of a resilient bushing of the character described, wherein the resilience of the bushing may be changed by making minor dimensional variations during the manufacture of the bushmg.
Another object is the provision of a resilient bushing of the character described, that is simple and inexpensive to manufacture, easy to assemble and which is relatively long-lasting in use.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.
DESCRIPTION OF THE DRAWINGS In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:
FIG. 1 is a perspective view of a retractable writing instrument embodying the present invention with the cap thereof shown in broken lines;
FIG. 2 is an enlarged fragmentary elevational view of the writing instrument, partly in section and with portions broken away for purposes of illustration;
2 FIG. 3 is an exploded perspective view of the operating parts of the retractable writing instrument; and
FIG. 4 is an enlarged perspective view of the resilient bushing per se.
DESCRIPTION OF THE INVENTION Referring now to the drawings, there is shown generally at 10 a writing instrument which may be a retractable, ballpoint pen. The instrument 10 comprises a barrel portion 12, a cap 14 and a writing point 16, through which the writing end 18 of a conventional retractable cartridge is adapted to propel and repel by mechanism now to be described.
Referring to FIGS. 2 and 3, it will be seen that the working components of the retractable mechanism comprise a carrier member 20, preferably constructed of molded plastic, said member comprising a hollow, elongated cylinder having an integral lug 22 extending outwardly adjacent one end thereof and having external threads 24 adjacent its other end. The carrier member 20 is freely received within stern member 26, preferably of metallic construction, said stern member also being in the form of an open-ended cylinder and having an elongated slot 28 therein, said slot having lateral extension 30 adjacent its closed end. A pair of oppositely disposed retaining ears 32 are integrally formed adjacent an end of stem 26, the purpose of which will hereinafter become apparent.
The forward end of stem member 26, i.e., the end opposite from the retaining ears 32, is received by open end 34 of metallic spacer tube: 36 and is a press fit therein so as to be firmly secured thereto. Spacer tube 36 is in turn fixedly received within barrel 12 by any suitable means, not shown. A metallic spiral collar 38 is freely positioned over stem member 26, said collar having an internal helix 40. It will be understood that in use, carrier member 20 is inserted within stem member 26 so that lug 22 extends outwardly through slot 28, said lug then being engaged with helix 40, as shown most clearly in FIG. 2. It will now be seen that by rotating the sprial collar 38, while holding barrel l2 and its associated spacer tube 36 against rotation, rectilinear movement will be imparted to carrier member 20 to either repel or propel same with respect to point 16. It will be understood that carrier 20 is connected to the writing cartridge 18 by any conventional means, not shown, so that as carrier 20 propels or repels, corresponding movement is imparted to the writing cartridge, all in a manner well known in the art, and as illustrated in aforementioned U.S. Pat. No. 3,436,160.
In order to maintain spiral collar 38 from moving axially, and at the same time in order to impart a desired resilient frictional drag on the rotary movement of collar 38, the following structure is provided. Abutting one end of collar 38 is a low friction bearing 42 which is actually nothing more than a washer constructed of Delrin or other suitable plastic material, said bearing in turn abutting a metallic washer 44 which washer engages and is retained by the aforesaid ears 32. In order to resiliently urge the collar 38 against bearing 42, a resilient bushing shown generally at 46 is provided at the opposite end of collar 38. The bushing 46 is preferably, although not necessarily, constructed of a plastic material, such as Delrin, and comprises a generally cylindrical body 48 having a first pair of oppositely disposed circumferentially extending openings 50 separated by wall portions 52 and a second pair of circumferentially extending openings 54 axially spaced from said first openings and staggered with respect thereto, whereby the wall portions 52 are actually centrally positioned with respect to the openings 54. The end of bushing 46 most closely adjacent to openings 54 is provided with an enlarged diameter washer-like portion 56. It will be understood that bushing 46 is slidably received over the outer surface of stem member 26 as are the aforesaid bearing 42 and washer 44. Actually, bushing 46 is sandwiched between the end 34 of spacer tube 36 and the adjacent end of collar 38. It will thus be seen that as stem member 26 is forced further into spacer tube 36, bushing 46 will axially compress, as shown in FIG. 2. What happens during this axial compression is that wall portions 52 deflect the portions 58 whereby the compressed bushing actually functions asa spring to impart a resilient bias against the end of collar 38. The more bushing 46 is compressed, the greater the resilient force imparted thereby, but one of the advantages of this bushing is that even when substantially in compression, its diameter remains constant. Also, as will be obvious, the compressed bushing 46 will exert a smooth and uniform resilient bearing against the adjacent end of collar 38. Another advantageous feature of bushing 46 is the fact that basically the same bushing can be made to exert a greater or lesser resilient force simply by varying the width of portions 58. In other words, if the portions 58 are made wider, then bushing 46 will exert a greater resilient force and vice versa.
In order to facilitate rotation of collar 38, a driver tube 60 if forced thereover, said driver tube in turn frictionally receiving cap 14, said cap frictionally engaging enlarged portions 62 on tube 60 whereby rotation of cap 14 causes corresponding rotation of tube 60 and in turn corresponding rotation of collar 38 which, as previously described, results in propelling or repelling Writing cartridge 18. In order to provide a better bearing for rotation of cap 14 and driver tube 60, it will be noted that washer portion 56 of bushing 46 acts as such a bearing, thus rendering unnecessary the provision of a separate low friction bearing Washer at this location. This is particularly true where bushing 46 is constructed of a low friction material, such as Delrin or the like, although it will be understood that insofar as the axial compression characteristics of bushing 46, it has been found that the bushing could also be constructed of a resilient metal. It will be understood that bearing 42 has substantially the same outer diameter as washer portion 56, whereby to provide a similar bearing at the opposite end of collar 38, for joumalling the rotatable driver tube 60 and cap 14.
When collar 38 has been rotated to fully propel writing end 18, as illustrated in FIG. 1, the lug 22 will automatically be positioned in lateral extension 30 of slot 28, thus preventing the carrier from being inadvertently forced rearwardly by pressure exerted against writing end 18, but rather said rearward movement can only be effected by reverse rotation of collar 38.
It should be emphasized that although the resilient bushing 46 has herein been disclosed and described in combination with a retractable writing instrument, it is 4 not limited to such use but rather may be effectively used wherever it is desired to impart a resilient thrust to an end of a rotating sleeve or collar in order to obtain a desired frictional drag against rotation of said sleeve or collar.
While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.
What is claimed is:
1. In a writing instrument of the type wherein a spiral collar is mounted for rotation over a fixed cylindrical stem member having a longitudinally extending slot therein, and wherein a carrier member is freely carried within said stem member, said carrier having a lug extending through said slot and making driving engagement with said spiral collar whereby rotation of the latter causes said carrier to propel or repel a writing cartridge connected thereto, the improvement comprising means carried by said stem member for imparting a frictional drag against rotation of said spiral collar, said means comprising a resilient bushing engaging at least one end of said spiral collar, said bushing comprising a cylindrical body freely and concentrically positioned on said stem with one end of said body engaging said collar, said body having an open portion in its cylindrical wall permitting axial compression of said bushing, and means on said stem axially compressing said bushing against said collar to impart a resilient thrust thereagainst, and means on said stem at the opposite end of said collar resisting said thrust.
2. In the writing instrument of claim 1, said bushing having a first pair of oppositely disposed elongated openings extending circumferentially of said cylindrical wall and a second pair of similar openings axially spaced from said first pair, said second pair of openings being staggered with respect to said first pair whereby the wall portions located between said first pair of openings are centrally positioned with respect to said second pair of openings.
3. In the writing instrument of claim 2, said bushing being of plastic construction.
4. In the writing instrument of claim 3, said thrust resisting means comprising a plastic washer.
5. In the writing instrument of claim 3, an elongated driver tube press-fitted over said collar whereby rotation of said tube causes rotation of said collar, said tube overlying said resilient bushing, the outer diameter of the compressible portion of said bushing being smaller than the inner diameter of said tube, said bushinghaving an integral washer portion of substantially the same diameter as the inner diameter of said tube, whereby said washer portion makes bearing engagement with said tube during rotation of the latter.