Claims:
1. A writing implement, comprising in combination, an elongated housing having a closed and an open end; elongated writing means having a writing end and a trailing end and being guided in said elongated housing for movement therein between a writing position in which said writing end extends beyond said open end of said housing, and a retracted position in which said writing end is withdrawn into said housing; biasing means constantly biasing said writing means in direction of said retracted position thereof; weight means abutting against said trailing end of said writing means and slidable in longitudinal direction relative to said housing, said weight means being operative for causing displacement of said writing means between said positions thereof in response to abrupt acceleration of said weight means in longitudinal direction towards said open end of said housing; and releasable lock means for retaining said writing means in said writing position against the biasing force of said biasing means, including a substantially annular enlargement fixed in said housing in the region of said closed end thereof and having toothed upper and lower edges, and a shaft member slidably mounted in said annular enlargement and having an upper and a lower end abutting against said weight means and said bevelled projections at said upper and lower end slidably engaging said toothed upper and lower edges of said annular enlargement to impart motion to said shaft member in response to abrupt acceleration of said weight means between a blocking position in which said writing means is in said writing position and a release position in which said writing means is in said retracted position.
2. A device as claimed in claim 1, wherein said toothed edges include teeth having a slight angle of inclination and teeth having an acute angle of inclination, and wherein said teeth having said slight angle of inclination determine said blocking position and said teeth having said acute angle of inclination determine said release position.
3. A device as claimed in claim 1, wherein said lower end of said shaft member abutting against said weight means is substantially spherical.
4. A device as claimed in claim 1, wherein said weight means includes a sleeve portion enclosing said writing means in the region of said tailing end thereof.
5. A device as claimed in claim 4, wherein said weight means is cartridge-shaped and encases said trailing end of said writing means.
6. A device as claimed in claim 1, wherein said biasing means is a spring member mounted in the region towards said open end of said elongated housing and is interconnected between said housing and said writing means.
Description:
BACKGROUND OF THE INVENTION
The present invention relates to an automatic writing implement, in particular a ballpoint pen, which incorporates an interior actuating mechanism.
Known in the art are actuating mechanisms for automatic writing implements which incorporate a positioning member for placing the writing member of the implement in its writing or retracted position. Such a positioning member is actuated by means of exterior pressure means, such as a push button, and is provided with bevelled projections which mesh with a cam surface in the writing implement to impact motion, directly or indirectly, to the writing member. Such positioning members are axially displacable between an upper position in which the writing member is in its retracted position and a lower position in which the writing member is in its writing position, and such positioning is carried out under the biasing force by a spring member.
Such exteriorly actuated mechanisms have the disadvantage that a connecting member has to be provided between the exterior push button and the interior positioning member.
This kind of arrangement is uneconomical and has the further disadvantage that in carrying the writing implement in the pocket, the push button may inadvertently actuated with the result that the writing member is released and may damage the clothes or other items of the bearer.
SUMMARY OF THE INVENTION
Object of the present invention is to provide a writing implement which avoids the above disadvantages and incorporates an activating mechanism without exterior means to actuate the same.
Such a writing implement according to the present invention comprises an elongated housing having a closed and an open end and elongated writing means guided in the housing for movement therein between a writing position in which the writing means extend beyond the open end of the housing and a retracted position in which the writing means is withdrawn within the housing, axially displacable in the housing and abutting against the rear end of the weight means to cause displacement of the writing means between its respective positions in response to abrupt acceleration of the weight means in longitudinal direction towards the open end of the housing, biasing means to constantly bias the writing member towards its retracted position and releasable lock means to retain the writing means in its writing position.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when used in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a preferred embodiment of a writing implement incorporating the novel actuating mechanism and arrangement according to the invention;
FIG. 2 shows a cross-sectional view of the cam arrangement incorporated in the actuating mechanism of FIG. 1;
FIG. 3 and 3a illustrate the positioning member incorporated in the actuating mechanism of FIG. 1; and
FIG. 4 illustrates a partial cross-sectional view of the weight member for displacing the writing member of the writing implement of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Shown in FIG. 1 is a writing implement 4 having an upper closed end 4a and a lower open end 4b. The upper end 4a, as shown, is closed by cap member 4c which is removable so as to permit easy access to the upper interior of the writing implement 4.
Arranged in the upper interior of the writing implement 4 is an actuating mechanism which is seen to consist of a positioning member 1 and a cam member 3 which rotatably mounts the positioning member 1.
As shown in FIG. 3 and 3a, the positioning member 1 is seen to comprise upper projections 2a and lower projections 2b. The projections 2a and 2b at their lower ends are bevelled and are operative to engage the toothed surfaces 3a and 3b of the cam member 3.
The cam member 3 forms an annular enlargement in the upper end of the implement 4 and is fixed therein. As shown, the angle of inclination of the projections 2a and 2b substantially correspond with the angle of inclination of the toothed surfaces 3a and 3b of the cam member 3.
The teeth formed in the upper edge surface 3a of the cam member 3 are seen to be overall identical and have a same angle of inclination while the teeth in the lower edge surface 3b have different angles of inclination. The tooth 3b**, for example, is deeper than the tooth 3b".
Abutting against the lower end of the positioning member 1 is a weight 10 which includes a weighted sleeve 11. The sleeve 11 encases the trailing end 6a of an elongated writing member 6. The weight is axially displacable in the housing 13 and is operative during abrupt acceleration thereof in longitudinal direction towards the open end 4b of the housing 13, to cause displacement of the writing member 6 between a writing position in which the writing end 6b extends beyond the open end 4b of the housing 13 and a retracted position in which the writing end 6b is withdrawn within the housing 13.
The writing member 6 is axially displacable in the housing 13 and is under the influence of a spring member 9 which interconnects the writing member 6 and the housing 13 in the forward region 7 thereof. To this end, the spring member 9 is mounted between a step portion 7a formed in the housing 13 and an annular enlargement 8 formed in the writing member 6.
It will be understood, that the spring member 9 constantly biases the writing member 6 towards its retracted position.
Upon shaking the writing implement 4 in forward longitudinal direction and with the projection 2b initially in engaged in the teeth 3b**, the weight member is abutting against spherical portion 12 at the lower end of the positioning member 1, will press the writing member 6 towards its writing position thereby momentarily releasing its engagement with the positioning member 1 whereby the projections 2b disengage the teeth 3b** and rotatably slide along the inclination 3b* into the shallow teeth 3b" thereby locking the writing member 6 in its writing position.
Upon subsequent shaking of the writing implement in forward longitudinal direction, the weight member 10 presses the writing member beyond its writing position thereby again momentarily disengaging the positioning member 1 whereby the projections 2b disengage the teeth 3b" and the projections 2a engage the inclination 3a' and rotatably slide towards the teeth 3a". Under pressure of the spring member 9, the projections 2b now regain their position into the deeper teeth 3b**.
It will be understood, that with the projections 2b in the shallow teeth 3b". The weight member 10 and consequently the writing member 6, are held in a lower or blocking position as compared with the release condition when the projections 2b are engaged in the deeper teeth 3b**.
The difference as to depth of the respective teeth is indicated by the distance "d.
Also, in order to maintain rotation of the positioning member 1 in the cam member 3, the teeth 3a are slightly offset relative to the teeth 3b.
It will be appreciated, that in moving the writing member 6 in direction towards its writing position, the projections 2a will rotatably engage the toothed surface edge 3a and that by movement of the writing member in direction towards its retracted position the projections 2b will slidably engage the toothed surface edge 3b, in which manner the projections will engage with their respective teeth.
It will also be clear that the mass of the weight 10 and the biasing force of the spring member 9 are proportioned so that a proper positioning of the writing member 6 in its respective position is ensured.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.