GB2202733A

GB2202733A - Writing instrument or liquid applicator

Info

Publication number: GB2202733A
Application number: GB08807070A
Authority: GB
Inventors: Yoshiomi Konose
Original assignee: Mitsubishi Pencil Co Ltd
Current assignee: Mitsubishi Pencil Co Ltd
Priority date: 1987-03-24
Filing date: 1988-03-24
Publication date: 1988-10-05
Anticipated expiration: 2008-03-24
Also published as: GB8807070D0; FR2612845A1; DE3809983A1; KR910003018Y1; GB2202733B; KR880017711U; IT8819932A0; JPS63152687U; IT1217355B

Description

2202733 WRITING INSTRUMENT OR LIQUID APPLICATOR The present inv_ention

relates to a writing instrument or liquid applicator for applying liquids such as writing ink, cosmetic liquid, paints, liquid drugs, liquid bonds, adhesives, and the like to a writing paper and like objects.' In a conventional type of such writing instrument or liquid applicator provided with a liquid-application portion, there is provided a valve unit for controlling an application liquid which is supplied to the liquidapplication portion. In operation of the instrument or applicator, although a predetermined amount of the application liquid should be constantly supplied to the liquid application portion of the instrument or applicator through the valve uri;7t,t-hereof each time such valve unit is operated, it is very difficult to realize such constant supplying of the predetermined amounts of the application liquid in the writing instrument or liquid applicator. This is a problem inherent in a conventional writing 20- instrument or liquid applicator.

It is an object,of the present invention to re- solve the above problem by providing a writing instrument or liquid applicator which has a novel and simple construction; is easily produced; and enables the user to realize the supply of a constant predetermined amount of an application liquid each time a valve unit of the instrument of applicator is operated by the user. According to the present invention, a writing instrument or liquid applicator comprises:

shaft sleeve; reservoir for an application liquid, defined within said shaft sleeve; a writing or liquid-application member for applying said application liquid to an object, mounted in a front-end portion of said shaft sleeve; valve unit disposed between said reservoir and said writing or'iiquid- application member; piston disk provided with a piston rod at its rear portion in aprojecting manner, said piston disk being slidably mounted in said reservoir so as to be brought into a watertight contact with said reservoir, said piston rod being provided with a plurality of sawtooth-shaped lateral projections which are provided on an outer surface of said piston rod at regular k intervals along a longitudinal axis of said piston rod; a push-out sleeve disposed outside said piston rod of said piston disk and provided with a front-end enlarged interior space adjacent a front-end flange of said push-out sleeve, said front-end flange extending radially inwardly; a cylindrical push member provided with a flange and loosely mounted on said piston rod in said front-end enlarged interior space of said push-out sleeve, said flange extending radially inwardly; and means for controlling a push-out stroke length of said push-out sleeve so as to keep said stroke length conitant.

One embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, of which:- Figs. 1 and 2 are longitudinal sectional views of a marking pen which is an embodiment of the writing instrument or liquid applicator of the present invention; Fig. 3 is a-dross-sectional view of the marking pen of the present invention, taken along the line 111-111 of Fig. 1; and Fig. 4 is a cross-sectional view of the marking pen of the present invention, similar to Fig. 3, in a condition in which the push-out sleeve is retracted so that a hook portion of the push-out sleeve passes through the sawtooth-shaped projection of the piston rod of the piston disk.

Referring to the drawings; the reference numeral 6 denotes a shaft sleeve of the marking pen. The shaft sleeve 6 defines an ink reservoir 7, and is p.ovided with a small- diameter portion 1 at its front end. An outer peripheral surface of the small-diameter portion 1 of the shaft sleeve 6 is threaded to form a male- screw portion 3 with which threadably engaged is a front sleeve 15 in which is mounted an ink-application member 13. This member 13 is provided with a flange-shaped base portion 14 at its rear end. The base portion 14 of the ink-application member 13 is clamped.b.--tween an inner shoulder portion of the front sleeve 15 and a guide ring 12 fixedly mounted in a front-end portion of the small-diameter portion 1 of the shaft sleeve 6. A front-end portion of the inkapplication member 13 extends outward from a front end of the front sleeve 15.

The small-diameter portion 1 of the shaft sleeve 6 communicates with the shaft sleeve 6 through an opening t forming a valve seat 4 of a valve unit which further comprises: a valve stem 9 having an expanded head portion with a tapered edge through which the valve stem abuts on the valve seat 4; a valve spring 10 constructed of a coil spring mounted in a position between a rear-end surface of the guide ring 12 and a front-end flat surface of the expanded head portion 8 of the valve stem 9; and the guide ring 12 forming a valve-spring support. The guide ring 12 is provided with a central through-hole 11 in which a front-end portion of the valve stem 9 is slidably received.

Axially slidably mounted,in the ink reservoir 7 is a piston disk 17 provided with an annular groove in its outer peripheral surface, in which annular groove an 0-ring 18 is fixedly mounted to seal a clearance formed between the outer peripheral surface of the piston disk 17 and an inner peripheral surface of the ink reservoir 7 which is defined by shaft sleeve 6 and a rront-end surface of the piston disk 17 so that the ink is received in the reservoir L7 in a position in front of the piston disk 17.

A piston rod 16, which is a portion of the piston -disk 17, extends from a central portion of a rear-end surface of the piston disk 17 in a direction parallel to a longitudinal axis of the shaft sleeve 6.

The piston rod 16 is provided with a plurality or sawtooth-shaped and equally-spaced projections 19 which are provided in an outer peripheral surface or the piston rod 16. Each of the projections 19 has a triangle shape in its cross section consisting or: a rear vertical surface perpendicular to the longitudinal axis of the shaft sleeve 6; and a front tapered surface. Each or the projections 19 may be an annular projection or may be constructed of a series or projection pieces arranged in a circumferential direction of the piston rod 16.

A cylindrical push-out sleeve 24 is loosely mounted on the piston rod 16 in the shaft sleeve 6, as shown in Fig. 1. The push-out sleeve 24 is provided with a Cront-end flange portion 27 extending radially inwardly. The flange portion 27 has a central hole through which the piston rod 16 passes forward. The push-out sleeve 24 is provided with an enlarged portion 21 at its rear-end portion behind a shoulde'r.portion 31 of the sleeve 24. The enlarged portion 21 has a larger diameter than that of the remaining portion of the push-out sleeve 24, and receives a push-out plug 20 therein.

In the push-out sleeve 24, between a rear surface of the front-end flange portion 27 and a front surface of a front-end inner shoulder portion of the push-out sleeve 24 is formed a front-end enlarged interior space in which is loosely mounted a cylindrical push member 30 provided with a front-end flange 29 which ext-ends radially inwardly. As shown in Figs. 3 and 4, the push member 30 is provided with a pair-of longitudinal slits 32 which extend from a front end of the flange 29 to a position in the vicinity of the rear-end portion of the push member 30, and are oppositely disposed from each other. The number of such slits 32 may be more than two, if necessary.

The push member 30 is slightly smaller in longitudinal length than the above.-mentioned front-end enlarged interior space of the push-out sleeve 24. In such front-end enlarged interior space, the width of the flange 29 of the push member 30 in a radial direction or the member 30 is slightly smaller in length than a clearance between an inner wall of the push-out sleeve 24 and a tip of the projection 19 of the piston rod 16, so that a radially-innermost-end of the flange 29 of the push member 30 is disposed at a nearer position to a center line oP the pistom,rod 16 than the tip of the projection 19 of the piston rod 16.

In the above marking pen of the embodiment of the present invention, as shown in Fig. 1, the push-out sleeve 24 is constructed of two components to facilitate the assembling operation of the marking pen in its production. However, the push-out sleeve 24 may be constructed of a single component, proviaed that such single component or sleeve 24 does not impair the assembling operation of the marking pen of the present invention.

A rear portion of the shaft sleeve 6 is enlarged in a step-like arrangement to provide a first inner shoulder portion 25 and a second inner shoulder portion 23, so that an inner diameter of the shaft sleeve 6 in a position between the shoulder portions 25 and 23 is slightly smaller-than an outer diameer of the rear-end portion of the push-out sleeve 24. In the push-out sleeve 24, the first inner shoulder portion 25 forms a spring support for supporting a front end of a coil spring 26 mounted in a position between an outer shoulder portion 31 of the pushout sleeve 24 and the first inner shoulder portion 25 of the shaft sleeve 6. On the other hand, the second inner shoulder portion 23 of the shaft sleeve 6 serves as a stopper means for preventing the outer shoulder portion 31 of the push-out sleeve 24 from being moved forward beyotid the second inner shoulder portion 23 of the shaft sleeve 6, when abutting on the outer shoulder portion 31 of the push-out sleeve 24.

In a rear-end opening of the shaft sleeve 6 is fixedly mounted a tail plug 5 having a central opening through which the push-out plug 20 extends rearward from the rear end of the tail Plug 5 as shown in Fig. 1. An inner-diameter of the central opening of the tail plug 5 at its rear end is smaller than an outer diameter of a rear end of the push-out sleeve 24 to prevent the- push- out sleeve 24 from passing through the central opening of the tail plug 5 rearward.

In order to keep a distance between a rear-end surface of the second inner shoulder portion 23 of the shaft sleeve 6 and a front-end surface of the tail plug 5 constant, a compression spring or coil spring 26 is 1 mounted in a position between a rear-end surface of the first inner shoulder portion 25 of the shaft sleeve 6 and a front-end surface of the enlarged portion 21 of the push-out sleeve 24. The above-mentioned distance corresponds to a push-out stroke length of the push-out sleeve 24 and an interval between the sawtooth-shaped projections 19 of the piston rod 16.

In the marking,p-en of the embodiment of the present invention, each of the components of the marking pen may be made of/conventional materials such as synthetic resins and the like. In the present invention, there is no limitation on such materials.

Fig. 1 shows a condition in which the marking pen is not subjected to a so-called push-out operation thereof, the condition being termed "a rest condition" of the marking pen. In this condition, when the user depresses the push- out plug 20 against the resilient force of the coil spring 26 with the use of his finger or thumb until the front-end surface of the enlarge portion 21 of the push-out sleeve 24 abuts on the front-end surface of the second inner shoulder portion 23 of the shaft sleeve 6, the push-out sleeve 24 moves forward by a predetermined stroke length as shown in Fig. 2.

When the push-out sleeve 24 is moved forward as described above, the push member 30 is also moved forward together with the-push-out sleeve 24 as is clear from Fig. 1, so that a rront-end surface of the flange 29 of the push member 30 abuts on a rear-end surface of the sawtooth-shaped projection 19 of the piston rod 16 to move the piston rod 16 and the piston disk 17 forward relative to the shaft sleeve 6.

Namely, the piston disk 17 is moved forward by means of the piston rod,, '1.6 relative to the shaft sleeve 6 by an amount of the predetermined stroke length to cause the pressure in the ink reservoir 7 to increase, so that the valve stem 9 is moved forward relative to the valve seat 4 against the resilient force of the valve spring 10, whereby ink received in the reservoir 7 is permitted to flow from the reservoir 7 to the inkapplication member 13 through the valve seat 4. After 2 0 a predetermined amount of ink is supplied to the inkapplication member 13, the valve stem 9 is moved rearward under the influence-of the resilient force of the valve spring 10 to seat on the valve seat 4 due to a pressure drop in the ink reservoir 7 caused by the above flow of ink. After that, when the user releases the push-out plug 20 from his finger of thumb, the push-out sleeve 24 returns to its initial rest. position shown in Fig. 1 under the influence of the resilient force of the coil spring 26. At this-time, as shown in Fig. 4, the push member 30 also moves rearward together with the push-out sleeve 24, because the flange 29 of the push member 30 abuts on the rear-end surface or the front-end flange 27 of the push-out sleeve 24 while being easily radially outwardly moved due to the provision of the slits 32 thereof so as to permit the sawtooth-shaped projections 19 of the piston rod 16 to pass through the flange 29 of the push member 5,,".!--reby the piston rod 16 is prevented from being moved rearward.

I

Claims

1. A writing instrument or liquid applicator compris- ing:

a shaft sleeve; a reservoir for an application liquid, defined with in said shaft sleeve; a writing or liquid-application member for apply ing said application liquid to an object, mounted in a front-end portion of said shaft sleeve; a-valve unit disposed between said reservoir and said writing or liquid-application member; a piston disk provided with a piston rod at its rear portion in a projecting manner, said piston disk being slidably mounted in said reservoir so as to be brought into a watertight contact with said liquid said piston rod being provided with a plurality of sawtooth-shaped lateral projections which are provided in an outer surface -of'-daid piston rod at regular intervals along alongitudinal axis of said piston rod; a push-ouV sleeve disposed outside said piston rod of said piston disk and provided with a front-end enlarged interior space adjacent a front-end flange of said push-out sleeve, said front-end flange extending radially inwardly; a cylindrical push member provided with a.flange 0 01 1 -A t and loosely mounted on said piston rod in said front-end enlarged interior space of said push-out sleeve, saidflange extending radially inwardly; and means for controlling a push-out stroke length of said push- out sleeve so as to keep said stroke length constant.

2. A writing instrument or liquid applicator substantially as hereinbefore described with reference to the accompanying drawings.

All Published 1988 at The Patent Office, State House, 66171 High Holborn, London WC1R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1187.