US3672783A

US3672783A - Twist-action retracting mechanism for use in writing instruments

Info

Publication number: US3672783A
Application number: US66728A
Authority: US
Inventors: Harold F Bajusz
Original assignee: Accutec Inc
Current assignee: Accutec Inc
Priority date: 1970-08-25
Filing date: 1970-08-25
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27
Also published as: CA921782A

Abstract

A TWIST-ACTION RETRACTING MECHANISM FOR USE IN WRITING INSTRUMENTS WITH FORWARD AND REARWARD BARRELS. THE OPERATING MECHANISM INCLUDES A TUBULAR ADAPTER HAVING A HELICAL SLOT ON THE INSIDE SURFACE AND SHAPED TO PERMIT MOUNTING OF THE ADAPTER WITHIN THE REARWARD END OF THE FORWARD BARREL. A HOLLOW INSERT MEMBER IS SHAPED TO ENGAGE THE INSIDE OF THE REARWARD BARREL AND TO RECEIVE THE REARWARD END OF THE WRITING CARTRIDGE. THE INSERT MEMBER ALSO INCLUDES A PLURALITY OF DISCRETE PROJECTIONS EXTENDING OUTWARDLY FOR ENGAGING THE HELICAL SLOT OF THE ADAPTER. ROTATION OF THE INSERT MEMBER WITHIN THE ADAPTER CAUSES AXIAL MOVEMENT OF THE INSERT MEMBER AND THE WRITING CARTRIDGE.

Description

June 27, 1972 BAJUSZ 3,672,783

H. TWIST-ACTION RETRACTING MECHANISM FOR USE IN WRITING INSTRUMENTS Filed Aug. 25, 1970 2 Sheets-Sheet 1 INVENTOR HAROLD F. BAJUSZ 37509960; f mdezsm K775111504) ATTORNEYS June 27, 1972 H. F. BAJUSZ TWIST'ACTION RETRACTING MECHANISM FOR USE IN WRITING INSTRUMENTS 2 Sheets-Sheet 2 Filed Aug. 25. 1970 INVENTOR HAROLD F. BAJUSZ fin arg fenz/elsmcgyz a oa) ATTORNEYS United States Patent 3,672,783 TWIST-ACTION RE'I'RACTING MECHANISM FOR USE IN WRITING INSTRUMENTS Harold F. Bajusz, Woodbridge, N.J., assignor to Accutec, Inc. Filed Aug. 25, 1970, Ser. No. 66,728 Int. Cl. B43k 24/06 US. Cl. 401-116 17 Claims ABSTRACT OF THE DISCLOSURE A twist-action retracting mechanism for use in writing instruments with forward and rearward barrels. The operating mechanism includes a tubular adapter having a helical slot on the inside surface and shaped to permit mounting of the adapter within the rearward end of the forward barrel. A hollow insert member is shaped to engage the inside of the rearward barrel and to receive the rearward end of the writing cartridge. The insert member also includes a plurality of discrete projections extending outwardly for engaging the helical slot of the adapter. Rotation of the insert member within the adapter causes axial movement of the insert member and the writing cartridge.

This invention relates to a writing instrument and more particularly to a twist-action retracting mechanism for use in a writing instrument to project and retract a writing carriage by rotation of the rearward barrel of the instrument.

Ball-point pens and retractable pencils have received wide acceptance and have been in use in a number of forms for some time. Although the retracting mechanisms heretofore used have served their purpose, they have not proved entirely satisfactory. Many of the retracting mechanisms are quite complex in construction and are relatively expensive to manufacture. Simpler mechanisms have also been developed with a saving in manufacturing costs, but these simply constructed mechanisms have proven to be unreliable for extended periods of use.

It is, therefore, an object of this invention to provide a simply constructed and reliable operating mechanism for use in a writing instrument.

Another object is to provide a writing instrument having an inexpensive but sturdy twist-action retracting mechanism.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages are realized and attained by means of the instrumentalities and the combinations particularly pointed out in the appended claims.

To achieve these objects, the present invention provides a twist-action operating mechanism for use in a writing instrument having a writing cartridge coaxially mounted within a forward barrel and a rear barrel. The mechanism includes a tubular adapter having an inner wall surface including a helical slot. The adapter is mounted within the rearward end of the forward barrel and is longitudinally fixed with respect to the forward barrel. An insert member is coaxially mounted within the rear barrel for rotation within the rear barrel, and the inset member engages the rearward end of the writing cartridge to move the cartridge forward with respect to the forward barrel when the insert member moves forward with espect to the forward barrel. The insert member also has a plurality of discrete projections extending outwardly from its outer wall, and the projections engage the helical slot of the adapter to cause ice linear movement of the insert member and the writing cartridge relative to the adapter and the forward barrel when the rear barrel is rotated.

Preferably, the helical slot is coextensive with only a portion of the inside surface of the adapter, and the inside diameter of this portion is smaller than the inside diameter of the remainder of the adapter. The insert member also preferably includes a first flange extension for engaging the smaller inside diameter of the adapter to limit relative movement of the insert member and the adapter in a first direction. A second flange extension integral with the insert member is also provided for engaging the adapter to limit relative movement of the insert member and the adapter in a second direction opposite from the first direction.

The invention thus uses a minimum number of parts to provide a smoothly functioning operating mechanism which has the precision feel of much more complicated and expensive mechanisms. Further, the forward and rearward movement of the writing cartridge is controlled within precise limits built into the mechanism. In addition, the small number of parts required by applicants apparatus, permits easy, inexpensive assembly of the writing instrument.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention.

In the drawings:

FIG. 1 is an elevation view of a preferred embodiment of the assembled writing instrument of this invention:

FIG. 2 shows a view of the assembled writing instrument, partly in section, showing the operating mechanism; and

FIG. 3 is an exploded perspective view of the writing instrument and operating mechanism of FIG. 1.

With reference now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 the assembled writing instrument of this invention which includes a tubular forward barrel 10 and a tubular rear barrel 12. A two-piece tubular adapter 14 having sections 15 and 15' for ease of assembly, as shown in FIG. 3, holds the forward and rearward. barrels together in the assembled position. This adapter is preferably made of nylon or of some other material having a low co-efficient of friction to enable easy operation of the retracting mechanism as will be described later. Adapter 14 and the other parts of the operating mechanism are shown in more detail in FIGS. 2 and 3.

A writing cartridge 16 extends longitudinally down the interior of

barrels

10 and 12 and includes a widened portion 18 for retaining a spring. As here embodied, spring 20 is mounted coaxially on cartridge 16'. One end of spring 20 is seated on the interior wall surface of the forward end of forward barrel 10 and the other end is seated on widened portion 18- to enable the cartridge to be selectively positioned as will be explained below.

As here embodied, and as illustrated in FIG. 3, tubular adapter 14 includes a helical slot 22 on its inside wall surface. As shown in FIG. 3, adapter 14 is formed of two parts 1-5 and 15' for ease of assembly. In its position in the assembled mechanism, adapter 14 is mounted within the rearward end of forward barrel 10 in a manner that longitudinally fixes the position of this adapter with respect to forward barrel 10. Adapter sections 15 and 1'5 includes projections :17 and 17, respectively, for engaging appropriately positioned holes in the adapter sections to prevent longitudinal movement between the sections when assembled. For example, projection 17' engages hole 19 and projection 17 engages a hole, not shown, in section 15".

As illustrated in FIG. 2, a helical slot 24 on the outside surface of adapter 14 engages a helical projection 26 that extends inwardly from the inner wall of forward barrel to hold the adapter and forward barrel in a longitudinally fixed relationship. Adapter 14 may be mounted within the forward barrel in a number of ways, such as by a friction fit for example.

The rearward end of adapter 14 includes a ridge 44 that extends outwardly around the circumference of the outer wall of the adapter. A slot 42 is formed on the inside wall surface of rear barrel 12. In the embodiment of FIG. 1, the slot is formed by expanding the outer wall surface adjacent slot 42 which creates a small ridge on the outer wall surface as there illustrated. The outer diameter of this ridge is sized to provide a very snug but slideable fit within the forward end of the rear barrel and to snap into slot 42 in the interior wall of rear barrel 12 to releasably snap-hold the rear barrel on the adapter in a fixed longitudinal relationship. However, ridge 44 can be rotated in slot 42.

The interior Wall surface of adapter 14 includes a front portion having a larger diameter than the inside diameter of the back portion of the adapter. These wall surfaces of these two portions are joined by a shoulder 48, illustrated in FIG. 3, which limits rearward movement of the cartridge during retraction as will be more fully explained below.

A flange member 21 is also located on the exterior surface of adapter 14 and extends around the circumference of the adapter to engage rearward end 23 of forward barrel 10 in the assembled position and to limit forward movement of adapter 14 as it is screwed into the forward barrel.

In accordance with the invention, an insert member is provided. The insert member is mounted so that twisting the rear barrel causes the insert member to rotate and advance or retract with respect to the forward barrel. The insert member houses the writing cartridge which is carried by the insert member during forward movement of the insert member. As here embodied, an insert member 28 is provided having a plurality of discrete projections 30. Insert member 28 is located within adapter 14, and adapter 14 is preferably made of nylon or of some other low co-efiicient of friction material to enable easy rotation of member 28 within adapter 14.

Projections 30 engage the inner helical slot 22 of adapter '14 (FIG. 3). One end of insert member 28 is tubular and defines a hollow bore 32 that receives the rearward end of writing cartridge 16. The diameter of bore 32 is large enough to permit easy insertion of cartridge 16. Blocking means project across the hollow bore to block off or narrow the passageway. In the illustrated embodiment, the central portion of the rear portion of member 28 is solid and forms a blocking means that seats the rearward end of the writing cartridge and causes the writing cartridge to be moved forward when the insert member moves forward.

The provision of a plurality of longitudinally and radially spaced projections on the insert member helps the operating mechanism to provide a smooth precise advance and retract movement. The several projections smoothly ride in helical slot 22 to create a linear force component from their rotational movement. The frictional force reaction against any one projection is less than would be encountered with a single projection. This result helps avoid binding of a projection in the helical slot, and the use of a plurality of projections helps provide a precision feel to the operating mechanism which has previously been attained only by much more complicated mechanism including many more separate elements machined or formed to very tight tolerances.

Preferably, projections 30 are aligned in two parallel rows along a portion of the length of insert member 28 and the rows are located from each other as measured around the exterior of the insert member. The projections of one row are also longitudinally staggered with respect to the projections of the other row, as illustrated in FIG. 3.

A radially extending projection is provided on insert member 28 to limit its linear movement. As here embodied, a first flange extension 34 is provided on the front end of insert member 28. The outside diameter of flange extension 34 is smaller than the inside diameter of the front portion of adapter 14, but greater than the inside diameter of the rear portion. Thus, shoulder 48 limits rearward movement of the insert member with respect to the adapter. Insert member 28 also includes a second linear motion limiting projection. As here embodied, the second projection flange extension 36 which engages the rearward end 38 of adapter 14 to limit forward movement of the insert member with respect to the adapter.

As here embodied, rear-ward barrel 12 is internally shaped to include a transversely extending member 40 that projects inwardly from the inner wall of barrel 12.

Transverse member 40 includes an opening 41 having a defined cross section, e.g., a square. However, it should be understood that the cross section of opening 41 may be of any desired shape to receive a similarly shaped flange extension 36 in rotationally coupled relationship. The dimensions of opening 41 slightly exceed the dimensions of flange extension 36 of insert member 28 to permit the insertion of flange extension 36- into hole 41 and to permit flange extension 36 to slide longitudinally with respect to transverse member 40. However, transverse member 40 locks flange extension 36, and therefore insert member 28, into a rotationally coupled relationship when flange extension 36 is inserted into opening 41. Thus, rotation of rear barrel 12 causes the simultaneous rotation of insert member 28.

Among the main advantages of the mechanism and writing instrument of this invention is the small number of parts and the ease of assembly of the parts to provide a smoothy operating and sturdy mechanism. In a preferred method of assembling the writing instrument, insert member 28 is positioned with projections 30 engaging helical slot 22 of one of the sections of adapter 14. The other adapter section is then placed over insert member 28 and is positioned so that projections 17 and 17' in sections 15 and 15', respectively, engage the appropriate holes. For example, projection 17' engages hole 19 and projection 17 engages an appropriately positioned hole (not shown) in section 15' to prevent relative longitudinal movement of the sections with respect to one another, member 28 is positioned within adapter sections 15 and 15' with flange extension 34 located forwardly of shoulder 48 and with flange extension 36 located in the rear of rearward end 38 of the adapter.

Flange extension 36 is then slidably inserted through opening 41 in rearward barrel 12, and insert member 28 together with adapter 14 are moved rearwardly until ridge 44 snaps into slot 42. This holds rear barrel 12, insert member 28 and adapter 14 together.

Spring 20 is then positioned over the writing end of cartridge 16 and engages widened portion 18. Forward barrel 10 is inserted over the writing end of cartridge 16 so that spring 20 engages the inner surface of the forward end of barrel 10 as well as widened portion 18 of the cartridge.

The rearward end of cartridge 16 is then inserted into hollow bore 32 of insert member 28 until the rearward end of the cartridge seats at the rearward end of insert member 28. Helical slot 24 of adapter 14 is then caused to engage helical projection 26, and adapter 14 is rotated in a clockwise direction, as viewed from the rear of the assembly, until flange member 21 engages the rearward end 23 of forward barrel 10.

In operation, writing cartridge 16 is extended by rotating rear barrel 12 in a clockwise direction as viewed from the rear of the assembled instrument. Clockwise rotation of barrel 12 causes the simultaneous clockwise rotation of insert member 28 due to the engagement of flange extension 36 and member 40 which rotationally couples rear barrel 12 and insert member 28.

Projections 30 on insert member 28 also rotate and must necessarily also move in a forward direction while rotating because projections 30 ride Within inner helical slot 22 in adapter 14. Thus, clockwise rotation of rear barrel 12 causes forward movement of insert member 28 with respect to adapter 14. This movement by insert member 28 in a forward direction continues until second flange extension 36 contacts the rearward end 38 of adapter 14 which limits forward movement of insert member 28.

Because the adapter mounted at the rearward end of forward barrel is in longitudinally fixed relationship with the forward barrel, the forward movement of insert member 28 causes writing cartridge 16, mounted for longitudinal movement with insert member 28, to move in a forward direction so that the writing tip is projected through opening 46 at the forward end of the forward barrel.

To retract the writing cartridge, the rearward barrel is rotated in a counterclockwise direction as viewed from the rear of the assembled instrument to cause a corresponding counterclockwise rotation of insert member 28. The movement of projections 30 within the inner helical slot 22 of adapted 14 causes the insert member to move in a rearward direction. Simultaneously, the action of spring urges the writing cartridge to retract in the rearward direction so that the cartridge is fully retracted when first flange extension 34 engages the smaller inner diameter of adapter 14 at shoulder 48.

The invention thus provides a simply constructed and reliable operating mechanism for use in a writing instrument in which the writing cartridge is projected and retracted by a simple twist action.

The invention in its broader aspects is not limited to the specific details shown and described and departures may be made from such details without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. A twist-action operating mechanism for use in a writing instrument having a writing cartridge coaxially mounted within a forward mounted barrel and a rear barrel, said operating mechanism comprising:

a tubular adapter having an inner wall surface including a helical slot, said adapter mounted within the rearward end of the forward barrel and longitudinally fixed with respect to the forward barrel; and

an insert member coaxially mounted within said rear barrel for rotation with said rear barrel, said insert member engaging the rearward end of the writing cartridge to move said cartridge forward with respect to said forward barrel when said insert member moves forward with respect to said forward barrel, said insert member having a plurality of discrete projections extending outwardly from its outer wall, said projections being spaced longitudinally and radially on said insert member at positions in alignment with said helical slot of said adapter for engaging said helical slot to cause linear movement of said insert member and the writing cartridge relative to said adapter and the forward barrel when said rear barrel is rotated.

2. A mechanism as in claim 1 wherein one end of said insert member is hollow to permit insertion of said writing cartridge Within said end of said insert member.

3. A mechanism as in claim 2 wherein said projections are aligned in radially spaced parallel rows along a portion of the length of said insert member.

4. A mechanism as in claim 2 wherein said projections are aligned in two parallel rows located from each other measured around the exterior of said insert member.

5. A mechanism as in claim 1 wherein said helical slot is coextensive with only a portion of the inside surface of said adapter and wherein a shoulder joins the inside diameter of said portion with the inside diamenter of the remainder of said adapter that is longer than the diameter of said portion.

6. A mechanism as in claim 5 wherein said insert member further includes a first flange extension for engaging the shoulder of said adapter to limit relative movement of said insert member and said adapter in a first direction.

7. A mechanism as in claim 6 further including a second flange extension integral with said insert member for engaging said adapter to limit relative movement of said insert member and said adapter in a second direction opposite from said first direction.

8. A twist-action operating mechanism for use in a Writing instrument having a writing cartridge coaxially mounted within a forward mounted barrel and a rear barrel, said operating mechanism comprising:

a tubular adapter having an inner wall surface including a helical slot, said adapter mounted within the rearward end of the forward barrel and longitudinally fixed with respect to the forward barrel;

an insert member coaxially mounted within said rear barrel for rotation with said rear barrel, said insert member engaging the rearward end of the writing cartridge to move said cartridge forward with respect to said forward barrel when said insert member moves forward with respect to said forward barrel, said insert member having a plurality of discrete projections extending outwardly from its outer wall, said projections engaging the helical slot of said adapter to cause linear movement of said insert member and the writing cartridge relative to said adapter and the forward barrel when said rear barrel is rotated; and

a transverse member extending across the interior of said rear barrel, said transverse member including an opening having a defined cross-section and said insert member including a rear flange extension having the defined cross-sectional shape and sized slightly smaller than said opening in said transverse member for receiving said insert member to permit longitudinal movement of said insert member relative to said rear barrel.

9. A retractable writing instrument, comprising:

a forward barrel;

a writing cartridge extending longitudinally down the interior of the barrel;

a spring coaxially mounted on the cartridge and having one end seated on the cartridge and the other end seated against the interior wall of the forward end of the barrel;

a tubular adapter having an inside wall surface including a helical slot and mounted within the rearward end of the forward barrel in a longitudinally fixed position with respect to said forward barrel;

a rear barrel; and

an insert member having one hollow tubular end;

said writing cartridge coaxially mounted within said hollow end of said insert member and said insert member including blocking means projecting into the hollow interior of said insert member for seating said cartridge and causing said cartridge to move forward when said insert member is moved forward;

said insert member having an outer wall surface including a plurality of projections longitudinally and radially spaced thereon at positions in alignment with said helical slot of said adapter for engaging said helical slot; and

said insert member being slidably connected to said rear barrel to permit simultaneous rotational movement of said insert member and said rear barrel and forward movement of said insert member and said cartridge with respect to said adapter and said forward barrel upon rotation of said rear barrel.

10. A writing instrument as in claim 9 wherein said helical slot is coextensive with only a portion of the inside surface of said adapter and wherein a shoulder joins the inside diameter of said portion with the inside diameter of the remainder of said adapter that is larger than the diameter of said portion.

11. A writing instrument as in claim 10 wherein said insert member further includes a first flange extension for engaging the shoulder of said adapter to limit relative movement of said insert member and said adapter in a first direction. I

12. A writing instrument as in claim 11 further including a second flange extension for engaging said adapter to limit relative movement of said insert member and said adapter in a second direction opposite from said first direction.

13. A writing instrument as in claim 12 wherein said rearward barrel includes a groove on the interior surface adjacent the forward end thereof and wherein said adapter includes a ridge for engaging the groove to releasably snap-hold said rearward barrel in position.

14. A mechanism as in claim 9 wherein said projections are aligned in radially spaced parallel rows along a portion of the length of said insert member.

15. A retractable writing instrument, comprising:

a forward barrel;

2. writing cartridge extending longitudinally down the interior of the barrel;

a rear barrel;

an insert member having one hollow tubular end;

said writing cartridge coaxially mounted within said hollow end of said insert member and said insert member including blocking means projecting into a hollow interior of said insert member for seating said cartridge and causing said cartridge to move forward when said insert member is moved forward;

said insert member having an outer wall surface including a plurality of projections engaging the helical slot of said adapter; and

said insert member engaging said rear barrel to permit simultaneous rotational movement of said insert member and said rear barrel and the forward movement of said insert member and said cartridge with respect to said adapter and said forward barrel; and

a transverse member extending across the interior of said rear barrel, said transverse member including an opening having a defined crosssection and said insert member including a rear flange extension having the defined cross-sectional shape and sized slightly smaller than said opening in said transverse member for receiving said insert member to permit longtitudinal movement of said insert member relative to said rear barrel.

16. A writing instrument as in claim 15 wherein said projections are aligned in two parallel rows along a portion of the length of said insert member.

17. A writing instrument as in claim 16 wherein said rows are located 180 from each other measured around the exterior of said insert member.

References Cited UNITED STATES PATENTS 2,753,844 7/1956 Boss 401-116 3,272,184 9/1966 Crowley 401-116 3,289,636 12/1966 Tessier 401- 3,298,509 1/1967 Hultgren 40178 3,436,160 4/1969 Lanoie 401116 FOREIGN PATENTS 659,140 3/1963 Canada.

LAWRENCE CHARLES, Primary Examiner