Coating implements with material supply – Projectable and retractable tool – Including retraction spring and projected-position retainer
Patent
1993-11-30
1995-05-23
Bratlie, Steven A.
Coating implements with material supply
Projectable and retractable tool
Including retraction spring and projected-position retainer
401111, B43K 2408, B43K 2406
Patent
active
054175046
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a refill unit for a writing instrument.
writing instruments, and ball point pens in particular, often incorporate a refill unit. Such a refill unit has a writing tip at one end and paired major and minor ratchet recesses at the opposite end. A pair of fingers provided internally of the writing instrument alternately engage the major and minor recesses of the ratchet on depression of a button on the writing instrument to cause the tip of the refill unit to retract into and extend from the casing of the writing instrument in turn, the action additionally being controlled by a coiled compression spring. Such a ratchet mechanism is shown and described in EP-A-0252694. Each depression, and release, of the button causes the refill unit to rotate by 90.degree. within the casing of the writing instrument. Thus, as users tend always to hold the writing instrument in the same orientation when writing, only two opposite sides of the writing tip of the refill unit are used to write with. This leads to uneven wear of the writing tip which, especially towards the end of the life of the refill, can result in uneven transfer of ink to the paper.
According to the present invention, there is provided a refill unit for a writing instrument, the unit having a writing tip at one end and a ratchet mechanism at the other end by means of which the unit can be turned and selectively extended from and retracted into the writing instrument, the ratchet mechanism being rotatable about the longitudinal axis of the unit with respect to the writing tip.
By this means, each time the refill unit is extended from or retracted into the writing instrument, the tip rotates by a substantially random amount which ensures a more even distribution of wear on the writing tip. It should be noted that the refill unit cannot rotate whilst writing since the unit is held, as conventionally, by a coiled compression spring.
Additionally, it has been found that the invention produces a "click" of lower pitch than that produced by conventional refill units when the refill unit is extended or retracted, the overall sound being less "tinny" and therefore more appealing to the majority of users.
Preferably, the rotating portion is constituted by a sleeve which carries recessed cam surfaces of the ratchet mechanism and which is retained for rotation on a post upstanding from the end of the refill unit remote from the writing tip.
An example of the present invention will now be described with reference to the accompanying drawings in which:
FIG. 1 is a partially sectioned elevation of a refill unit;
FIG. 2 is a partially sectioned view of a ratchet;
FIG. 3 is a view from one end of the ratchet;
FIG. 4 is a view from the other end of the ratchet; and,
FIG. 5 is a cross-sectional view of the ratchet.
In FIG. 1 there is shown a refill unit 1 for a ball point pen, which has a casing 2 divided generally into a body portion 3 and a shank portion 4 of reduced diameter. The shank 4 carries a conventional writing tip 5 in which is mounted a ball 6.
A ratchet head 7 is fixed in the other end of the body portion 3. The ratchet head 7 is a two part assembly and consists generally of a sleeve 10 and a mount 11. The mount 11 comprises a plug portion 12 which is held within the open end of the body 3 of the refill unit and spigot 13 of reduced diameter which extends away from the plug 12 in a direction opposite the writing tip 5. The spigot 13 has a flare 14 at its outermost end and the sleeve 10 is held for rotation about the spigot 13 between the plug 12 and the flare 14, after having been inserted on the spigot.
The sleeve 10 is provided with conventional major and minor ratchet recesses 20,21. The operation of this aspect of the ratchet, whereby the writing tip is extended when the fingers provided internally of the casing of the writing instrument project into the minor recesses 21 and the writing tip is retracted when the fingers project into the major recesses 20, is completely conventional and well understood by persons skilled in the
REFERENCES:
patent: 4991988 (1991-02-01), Snell et al.
patent: 5184908 (1993-02-01), Yamamoto et al.
Andrews Neville E.
Booker Brian A. J.
Bratlie Steven A.
Parker Pen (I.P.) Limited
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