GB2177294A

GB2177294A - Writing or painting instrument

Info

Publication number: GB2177294A
Application number: GB08613043A
Authority: GB
Inventors: Yoshiomi Konose
Original assignee: Mitsubishi Pencil Co Ltd
Current assignee: Mitsubishi Pencil Co Ltd
Priority date: 1985-05-29
Filing date: 1986-05-29
Publication date: 1987-01-21
Also published as: FR2582582A1; DE3618078A1; IT1204880B; IT8620595A0; GB8613043D0; FR2582582B1; GB2177294B

Abstract

A press-action writing or painting instrument enables ink to flow to its brush-like point through a pressing action of a cap 7 attached to a rear end of an inner shaft 8. The latter is slidably received in an outlet shaft 1 an inner diameter of which is so determined as to come extremely close to an outer diameter of the inner shaft to ensure a neat sliding movement of the inner shaft without any looseness, while air in a space defined by these outer and inner shafts escapes outside the instrument through slots 19a or apertures 18 provided in the outer shaft and/or the inner shaft, so that a smooth pressing operation of the inner shaft is possible. <IMAGE>

Description

SPECIFICATION Writing or painting instrument The present invention relates to a writing or painting instrument in which a member is slidably received in a tubular outer shaft and is movable through a pressing action to feed writing or painting fluid to a tip of the instrument.

Hitherto, such a type of writing or painting instrument has been proposed with wide variations. In one such variation, where a slidable member is moved only in its longitudinal direction in a smooth manner through a pressing action, it is necessary to minimize clearance between an outer peripheral surface of such slidable member and an inner wall of an outer shaft receiving the slidable member therein.

However, where such clearance is too small, air received in a space defined by the outer shaft and member can not easily escape and prevents the pressing action being carried out in a smooth manner. It also makes it difficult to conduct a rapid return operation of the movable member. Where such clearance is increased to enable the air to escape, other problems occur in that the slidable member moves in the outer shaft in a loose manner and in that the durablity of the slidable member is reduced.

The present invention seeks to provide an improved writing or painting instrument. Accordingly the present invention provides a writing or painting instrument comprising a member which is axially moved in an outer shaft through a pressing action for feeding writing or painting fluid to a tip of the instrument; and means for enabling air received in a space defined between said movable member and said outer shaft to escape outside said writing instrument during movement of said member.

The present invention is further described hereinafter, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through a preferred embodiment of writing instrument according to the present invention; and Figure 2 is a enlarged perspective view of a knurled tail plug in the writing instrument shown in Figure 1.

In Figure 1, the reference character "A" denotes a brush-like pen provided with a main body in the form of a tubular outer shaft 1, a front end of which is threadably connected to a co-axial tubular front tip 2. An ink feed pipe 3 and a disc-like plug 4 abutting against a front end surface and radial flange of the ink feed pipe 3 are clamped and fixed between a front end of the outer shaft 1 and an inner shoulder of the front tiip 2. The front tip 2 contains a projecting brush core 5 covered by a holder 6 and bonded to the front tip 2.

The core 5 connects with the ink feed pipe 3 through an opening 4a provided in a central portion of the plug 4.

Co-axially within the outer shaft 1 is an axially slidable thrust sleeve in the form of a tubular shaft 8 which is smaller in length and diameter than the outer shaft 1, the clearance between the outer peripheral surface of the inner shaft 8 and the inner wall of the outer shaft 1 being extremely small. An internal, integral tubular spring support 9 extends rearwardly of the inner shaft 8, from a position adjacent the front end of the latter. The interior of the inner shaft from the spring support to 9 to the rear end of the shaft 8 defines an ink reservoir 8a, the rear open end of the shaft 8 being closed by an inserted tail plug 16 so that the ink reservoir 8a is formed into a cartridge-like shape.The tail plug 16 is provided with a concave or recessed outer end portion 1 6a for receiving a cap 7 which normally covers the front tip 2 when the brush-like pen "A" is not in use and is removed in use. By Pressing the cap 7 when the latter is inserted in the concave portion 16a of the tail plug 16 the inner shaft 8 can be slid axially of the outer shafter 1 toward the brush core 5.

A sleeve-like tubular valve seat 12 is coaxially located within the inner shaft 8 adjacent its front end and abuts against a shoulder provided in a base portion of the spring support at its conjunction with the inner shaft 8. The valve seat is retained in position against the shoulder by a securing sleeve 14 which is threadedly engaged in the front end of the inner shaft 8 and which clamps a circular ink seal 13 between itself and the valve seat 12.

The ink feed pipe 3 extends through central apertures in each of the securing sleeve 14, seal 13 and valve seat 12. The seal 13 is sealed (e.g. hermetically) with the ink feed pipe 3 to prevent the ink contained in the ink reservoir 8a leaking beyond the seal toward the brush core 5. At its rear, on the reservoir side of the seal, the ink feed pipe 3 has an ink inlet opening 3b in its side wall. A valve closure 10 is located in the spring support 9 and is urged towards the valve seat 12 by a coil spring 11 mounted between the spring support 9 and an external shoulder of the valve closure 10.Under normal conditions, at rest, a front end taper portion of the valve closure 10 is sealingly engaged with the valve seat 12, with the inner shaft 8, and thus the valve seat, being urged rearwardly relative to the valve closure under the action of the resilient force of the coil spring 11 so as to retain the valve closure 10 in firm sealing engagement with the valve seat 12.

A tubular cap 1 9 is threadably connected to and closes the rear end of the outer shaft 1, the cap abutting against a rear end of the tail plug 16 which is a press-fit in the rear end of the inner shaft 8, to retain the inner shaft 8 assembled in the outer shaft 1. The tubular cap 19 has a U-shaped cross section as shown in Figure 1 and is provided with one or more apertures 19a for enabling the air re ceived in the brush-like pen "A" to escape outside the pen "A".

In the brush-like pen "A" having the above construction, the ink reservoir 8a is normally kept in a sealing condition through engagement of the valve closure 10 with the valve seat 12. When the pen is used, the cap 7 is inserted into the tail plug 16 and is pressed to drive the cartridge-like inner shaft 8 forward against the resilient force of the spring 11, with the result that the valve seat 12 is driven forward to open the valve (the valve closure 10 abutting against the rear end of the ink feed pipe 3). When the valve is opened, ink in the ink reservoir 8a is released to flow forward. The ink flows into the ink feed pipe 3 through the ink feed opening 3b and is fed to the brush core 5. Flow of ink to the brush core around the outside of the ink feed pipe is prevented by the seal 13.

When the cap 7 is released after being pressed, the inner shaft 8 is driven by the resilient force of the spring 11 to return its initial position to seat the valve closure 10 on the valve seat 12 and prevent further flow of ink.

Since the cap 7 is depressed at a considerable speed, it is necessary to ensure that air received in the annular space between the outer shaft 1 and the inner shaft 8 near the front end of the inner shaft 8 can swiftly escape outside of the outer shaft 1 to ensure a smooth pressing action of the cap 7. In order to ensure such smooth pressing action one or more small apertures 18 are provided in a portion of the outer shaft 1 adjacent the tip 2.

The apertures enable the air received in a space 17 adjacent the tip 2 to escape rapidly.

As shown in Figure 2, a rear portion of the tail plug 16 is of slightly larger external diameter than the inner shaft 8, and is provided with a plurality of axial slots in its outer peripheral surface to give the rear portion a knurled shape. The slots also assist in the rapid escape of air received in the space 17 when the inner shaft 8 is pressed forward to reduce the volume of the space 17.

It is also possible to provide one or more such slots over the full length of the rear portion of the tail plug 16, provided that the rear portion is similar to the inner shaft 8 in outer diameter and is not inserted into the inner shaft 8. In this event the inner diameter of the outer shaft 1 is so chosen as to be extremely close to the outer diameter of the inner shaft 8, so that the inner shaft 8 is neatly received in the outer shaft 1 without any looseness.

The slots may alternatively or additionally be formed in the inner wall of the outer shaft.

As described above, the present invention makes it possible, by providing a means enabling the air received in the space 17 defined between the outer shaft 1 and the inner shaft 8 to easily escape outside the outer shaft 1, to choose the inner diameter of the shaft 1 and the outer diameter of the inner shaft 8 sufficiently close to reduce or eliminate any looseness of the inner shaft 8 during the pressing action.

Claims

1. A writing or painting instrument comprising a member which is axially moved in an outer shaft through a pressing action for feeding writing or painting fluid to a tip of the instrument; and means for enabling air received in a space defined between said movable member and said outer shaft to escape outside said writing instrument during movement of said member.

2. A writing or painting instrument as claimed in claim 1, wherein said means comprises at least one small aperture for enabling the air to escape, said aperture being provided in a portion of said outer shaft, which portion bounds on said space.

3. A writing or painting instrument as claimed in claim 1 or 2, wherein said means comprises one or more slots provided in an inner wall of said outer shaft.

4. A writing or painting instrument as claimed in claim 1, 2 or 3, wherein said means comprises one or more slots provided in an outer wall of said movable member.

5. A writing or painting instrument as claimed in claim 3 or 4, wherein said slots are concave in cross-section.

6. A writing or painting instrument as claimed in any of claims 1 to 5 wherein said means comprises one or more of knurled members provided in a predetermined portion of said movable member.

7. A writing or painting instrument substantially as herebefore described with reference to the accompanying drawings.