GB2129741A - A ball pen with an elastically seated refill - Google Patents

Abstract

A ball pen with mechanism for extending and retracting a refill (3) on a helical path in axial direction, comprising a resilient element (13) arranged in the motion mechanism for eliminating differences in the pressure acting on the point of the refill in contact with the writing surface. The element (13) which is biased by a spring (17) is slidably connected to a housing 8 by a pin 8 running in helical recesses (12), and the housing is rotatable in a sleeve 11 fixed to the upper part of the pen body. <IMAGE>

Description

SPECIFICATION A ball pen with an elastically seated refill The invention relates to a ball pen (also known as ballpoint pen) with an elastically seated refill.

Ball pens have been so designed that the pressure exerted by the hand on the ball seated in the socket of the pen and transmitted through various functional elements of the motion mechanisms on to a writing surface is "hard", and its magnitude varies from individual to individual. Springs which determine the limit positions of extension and retraction of the refill in the bodies of retractable ball pens have only a single purpose, namely to take part in extending and retracting and they have no effect on controlling the pressure exerted by the hand on the ball of the refill and transmitted on to a writing surface.

The writing function of a ball pen resides in principle in the fact that a ball freely rotating in a socket of writing point transports ink from a reservoir on to paper. Rotation of the ball is therefore a necessary condition for writing. For the ball to rotate, its friction on the writing surface, e.g. paper, must be greater than its friction in its socket inside the writing point; as its friction in the socket of the point is practically constant, whereas its friction on paper is directly proportional to the force applied to the ball pen during writing, it is evident that there exists some minimum force, which must be exerted on the ball pen for the ball to rotate and to write reliably.

The smaller the minimum force needed, the smoother the writing; the pen also writes more softly, slides better, the writing is less tiresome and the pen is classified as a product of high quality. To achieve such quality advantages various means are used: to achieve a low friction ofthe ball in the socket a ball is used which is made of a very smooth and hard material, e.g. austenitic steel, sapphire, corundum, carbide, tungsten or a suitable sintered carbide, which also increases the service life of the ball and its shape permanency, or the ball socket is made of a very hard and smooth material.

In order to increase the friction of the ball on paper and to transport the writing ink on paper more effectively, balls having a porous surface are used.

To facilitate the flow of ink, inert gas under pressure may be introduced into the ink reservoir and in this way the ink is forced out in sufficient quantity.

All these measures do not solve the main physiological factor of writing, which affects the course of the force exerted on the pen and, in this way, the hand fatigue when writing: as the pen is moved towards the writing person it is gradually erected with respect to paper, the point of holding the pen moves up, and if the refill is stiffly fixed in the ball pen, it transmits the pressure of the hand directly, and in this way the vertical component of the force exerted by the hand and consequently the pressure acting on the writing surface, increase - and that is the main factor which causes the fatigue of the hand during writing as well as the subjective feeling that the writing is tiresome, that the pen does not slide sufficiently smoothly, etc.The principle resides in the fact that for controlling the increased vertical pressure or resistance during writing, the pen must be more tightly pressed by fingers, whereby the hand becomes more tired. As the pen is erected so are the fingers, which increases fatigue due to the tightening of tendons.

The above-mentioned drawbacks, as well as increased costs on special materials and structural solutions of the functional parts of the motion mechanisms of a ball pen may be obviated by a ball pen according to the invention, in which a resilient element, provided with a pin, is on the one hand slidablyseated in the housing of the motion mechanism biassed by a compression spring and on the other hand connected by means of the pin, guided by its ends in helical recesses with a gate; the refill of the pen being connected to a split in the resilient element.

Advantages of the invention reside in the structural arrangement of the motion mechanism, in which the resilient element is utilized as a functional motion member, whereby it is achieved that the refill is not seated stiffly, so that when a higher pressure is exerted by hand it may be partially retracted and in this way it reduces both the effort of fingers when pressing the body of the pen, and also lifting and bending of fingers, which decreases the effort of tendons and muscles, this being important especially, when writing for a long time.

In order that the invention may be clearly understood and readily carried into effect, a preferred embodiment thereof is, by way of example, hereinafter more fully described and illustrated in the accompanying diagrammatic drawing, in which a longitudinal section of the whole structural arrangement of the pen is shown.

According the the embodiment shown in the drawing, the ball pen comprises a body, which is composed of an upper part 1 and a lower part 2. The upper part 1 is provided with a clip 18 and houses a motion mechanism for extending and retracting a refill 3, which is provided with a gland 4 with a hole 5 and a venting system 6 and is seated in the lower part 2 of the body. The motion mechanism consists of a gate 11, fixed in the upper part 1 of the body, provided with two helical recesses 12, situated one opposite the other, and of a housing 8, which is seated to be freely rotatable in the gate 11.A resilient element 13 which may be of the configuration and/or design described and illustrated in our copending application No. 8329983 (Czechoslovak patent application PV 8018-82), is a functional part of the motion mechanism and is also designed for an elastic contact of the refill 3 with the writing surface and is situated with a free push fit in the housing 8, with which and the gate 11 it is connected by means of a pin 16 passing transversely through the element 13 via limiting grooves 19 in the housing 8 and seated by its both ends in the helical recesses 12 of the gate 11. Between a supporting shoulder 14 of the element 13 and an upper shoulder 9 of the housing 8 a compression spring 17 is slid over the element 13.

The lower part 2 of the body is provided with a threaded insert 7 and is connected to the upper part 1 of the body by screwing a threaded shoulder 10 of the housing 8 into the threaded insert 7 in the lower part 2 of the body. When both the parts 1,2 of the body are assembled a shaped split 15 in the resilient element 13 is seated in the hole 5 of the gland 4 of the refill 3.

By turning the lower part 2 in the upper part 1 in one direction, the refill 3 is extended out of the lower part 1, and by turning the lower part 2 in the opposite direction, the refill 3 is retracted into the lower part 2.

Both these operations are performed by means of the motion mechanism, on which, when the lower part 2 is turned, also the element 13 is turned in the gate 11 together with the housing 8, and they move in a rotating motion on a helical path defined by the helical recesses 12 upwards against the pressure of the compression spring 17 or on the same helical path downwards in the direction of the pressure exerted by the compression spring 17, which, as evident from the description, is designed for limiting fixed positions of the extension and retraction of the refill 3. When the refill 3 touches the writing surface, an elastic contact of the writing ball is caused by the resilient element 13, the notches of which continuously respond to the non-uniform pressure of the hand on to the ball pen.

In this specification the term "ball pen" is intended to include any writing or drawing implement in which a freely rotatable ball deposits an ink trace, and "ink" is intended to include any material transmitted by said ball on a surface in order to deposit a trace.

Claims (5)

1. A ball pen with an elastically seated refill, comprising a body, composed of a lower part with a freely seated refill and of an upper part, and a built-in motion mechanism for extending and retracting the refill, a gate provided with helical recesses and a resilient element, wherein the resilient element, provided with a pin, is on the one hand slidably seated in a housing of the motion mechanism, biassed by a compression spring, and on the other hand connected by means of the pin, guided by both its ends in the helical recesses with the gate, the refill of the pen being connected with a split in the resilient element.

2. A ball pen according to Claim 1, wherein the resilient element is substantially tubular and has at least two transverse notches extending from opposite sides in a staggered arrangement.

3. A ball pen according to Claim 2, wherein the notches extend through more than half of the cross-section of the resilient element.

4. A ball pen constructed, arranged and adapted to operate substantially as herein described with reference to, and as shown in, the accompanying drawing.

5. A ball pen comprising a built-in motion mechanism for extending and retracting a refill and a resilient element elastically supporting the refill.