A rotary-cam ball-point pen

Abstract: A rotary-cam ball-point pen having an outer sleeve (1), a rotary-cam mechanism (5) comprised of a cam body (2) provided on the inside of the outer sleeve, a rotary-cam (2) engaging the cam body, and a cam bar (4) engaging the rotary-cam, and a refill (7). The rear portion of the refill is loaded backward by an elastic body (6) inserted into the rotary-cam. The cam bar has a structure with flexibility in which the cam bar can be distorted inward by applying a radial force. Since the cam bar is inserted into the outer sleeve from the rear side of the outer sleeve, it is possible to form a clip (21) of an integral part of the cam bar, or a decoration (22) having dimensions larger than the outside diameter, or a knocking cap.

Description: 1. Field of the Invention The present invention relates to a rotary-cam ball-point pen in which a refill pen point can be pushed out of the head member of the ball-point pen against the elasticity of an elastic body by knocking the rear end of the ballpoint pen. The ball-point pen can be maintained with the pen point pushed out of the head member of the ball-point pen, by a rotary-cam engaging a cam body. The pen point can be withdrawn into the head member of the ball-point pen by the elasticity of the elastic body by releasing the engagement of the rotary-cam with the cam body. 2. Description of the Prior Art A conventional rotary-cam ball-point pen as it is described for example in FR-A-1156612 and EP-A-0407002 has an outer sleeve, a rotary-cam mechanism comprised of a cam body provided on the inside of the outer sleeve, a rotary-cam engaging the cam body, and a cam bar engaging the rotary-cam. A refill, being a rear portion is loaded backward by a spring provided between the head member screwed on the forward end of the outer sleeve and a spring bearing formed on the refill so that the rear portion of the refill is forced into the rotary-cam. In the conventional ball-point pen of FR-A-1156612, when the rotary-cam, cam bar, and refill are set in the outer sleeve, the rotary-cam, cam bar and refill are inserted from the forward end into the outer sleeve under a state where the rear portion of the refill is inserted into the rotary-cam with the cam, bar engaging the rotary cam. Projections formed on the cam bar we inserted into grooves formed oil the cam body, a spring is put on the forward portion of the refill, and the head member is screwed on the forward end of the outer sleeve. Therefore it is not easy to set up the rotary-cam mechanism and the refill in the outer sleeve and besides since the cam bar is inserted from the forward side of the outer sleeve, it is impossible for the cam, bar to be provided with, a clip or a decoration having dimensions larger than the outside diameter of the outer sleeve or a knocking-cap being all integral part of the cam bar. Therefore, it is necessary to attach a clip, or a decoration or a knocking cap after setting the cam bar in the outer sleeve. Accordingly, the number of parts is increased, and a long time is required for assembly of parts. The ball-point pen according to EP-A-0407002, which represents the prior art as referred to in the pre-characterising portion of claim 1, shows a rotary cam follower provided with axially extending ribs being inserted into respective grooves of a stationary cam. Additionally a knocking rod of the ballpoint pen is provided with projections extending axially outwardly and being inserted in respective guide slots or slits in the cylinder of the pen in order to ensure a stable action of the knocking rod. In another embodiment according to EP-A-0407002 said projections may be in the form of a peripheral flange extending around the entire outer surface of the knocking rod. For this embodiment the said guiding slots or slits are replaced by a cylindrical recess. But this makes it necessary to take additional measures to limit rotation of the knocking rod within the cylinder. BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide an improved ball-point pen in which setting up a rotary-cam mechanism and a refill in an outer sleeve can be easily carried out and a cam bar can be inserted from the rear end of the outer sleeve so that a clip or a decoration or a knocking cap having dimensions larger than the outside diameter of the outer sleeve is possible. The above-mentioned object is attained by a rotary-cam ball-point pen according to claim 1. Further advantageous features are introduced by the dependant claims. Since a rotary-cam ball-point pen according to the present invention has the above-mentioned structure, when the rotary-cam mechanism and refill are set in the outer sleeve, the rotary-cam mechanism and refill are inserted from the forward end of the outer sleeve in a state where the rear portion of the refill is inserted into the rotary-cam, an elastic body is put on the forward portion of the refill, and the head member is screwed on the forward end of the outer sleeve by which the rotary-cam, the refill, the elastic body and the head member are set up. Thereafter, the cam bar is inserted into the outer sleeve from the rear end of the outer sleeve, while the cam bar is deformed inward by the elasticity of the cam bar, which elasticity enables the projections of the cam bar to get over the rear portion of the cam body into grooves of the cam body by which the attachment of the cam bar to the cam body is made. According to the present invention, the number of parts is decreased, and less time is required for assembly of parts. In the present invention the cam body may be provided with a guide, which guides the projections of the cam bar. By the guide, the projections of the cam body can be easily inserted into the grooves of cam body. Further, in the present invention, the cam bar may be formed with slits, slots or cuts. The slits, slots or cuts give flexibility to the cam body so that the cam bar can deform inward by applying a radial force to get over the rear portion of the cam body and go into the grooves of the cam body. The above and other novel festures and advantages of the invention will be more fully understood from the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings; Fig. 1 illustrates in vertical section a first embodiment of a rotary-cam ball-point pen according to the present invention; Fig. 2 illustrates in vertical section an important part of a second embodiment of a rotary-cam ball-point pen; Fig. 3(a) illustrates in vertical section a cam bar according to the present invention; Fig. 3(b) illustrates in a perspective view a rotary-cam and the cam bar according to the present invention: Fig. 4 is a schematic illustration of a cam body according to the present invention; Figs. 5 and 6 show another embodiment of a cam bar of the present invention, Fig. 5 being a vertical section thereof and Fig. 6 being a plan view thereof; and Fig. 7 shows in vertical section an important part of a third embodiment of a rotary-cam ball-point pen. DETAILED DESCRIPTION Referring to Fig. 1, a rotary-cam ball-point pen according to the present invention comprises outer sleeve 1, and cam mechanism 5 comprised of cam body 2 provided on the inside of the rear part of outer sleeve 1, Rotary-cam 3 engages cam body 2 and cam bar 4 engages rotary cam 3, and refill 7. Cam body 2 may be formed integrally with outer sleeve 1 or cam body 2 may be attached to the inside of outer sleeve 1 by a force fit, adhesion, or screwing. Spring 6 is provided between spring bearing 14 on refill 7 with its rear, end is inserted in to rotary cam 3 and head member 13 removably screwed on the forward end of outer sleeve 1. The attachment of head member 13 to outer sleeve 1 is made by insertion, engagement, or screwing. Cam bar 4 has a structure with flexibility in which the cam bar can be distorted inward by applying a radial force. The number of projections 8₄ of cam bar 4 equals the number of grooves 9 of cam body 2, for example 9, but usually less than 6, or for example 2(Figs 3(a) and (b) ). Pairs of projections are diametrically opposed. The number of projections 16₃ of rotary cam 3 is 3 in this case (Figs. 3(a) and (b) ). When the pen point is drawn in, cam faces 17₄ of cam bar 4 engage cam face 18₃ of rotation cam 3, and projections 8₄ of cam bar 4 and projections 16₃ of rotary-cam 3 are inserted into grooves 9 of cam body 2. Further, the engagement of cam face 18₃ of rotary cam 3 with cam face 19₂ of cam body 2, and the insertion of projections 16₃ of rotary-cam 3 into grooves 9 of cam body 2 are alternatively made. Reference number 21 designates a clip formed integrally with cam bar 4. Fig. 2 illustrates in vertical section an important part of a second embodiment which has the same structure as the first embodiment, in which headed cam, body 2 is attached to the inside of the rear end of outer sleeve 1 by screwing. In the first and second embodiments shown in Figs. 1 and 2 projections 8₄ of cam bar 4 and projections 16₃ of rotary-cam 3 are inserted into grooves 9 of cam body 2. When the rear end of cam bar 4 is knocked in a state where cam faces 17₄ of cam bar 4 engage cam faces 18₃ of rotary-cam 3, cam bar 4, rotary-cam 3, and refill 7 are moved, forward against spring 6 so that pen point 20 of refill 7 is pushed out of head member 13 of outer sleeve 1 while pen point 20 of refill 7 is kept in a state with pen point 20 of refill 7 pushed out of head member 13 of outer sleeve 1 by rotary-cam 3 being turned a given degrees by means of cam faces 17₄ engaging cam faces 18₃ so that cam faces 18₃ engage cam faces 19₂ of cam body 2. When pen point 20 of refill 7 is drawn into head member 13 of outer sleeve 1, the rear end of cam bar 4 is knocked releasing cam faces 18₃ of rotary cam 3 from cam faces 19₂ of cam body 2. Thereafter projections 16₃ of rotary cam 3 and projections 8₄ of cam bar 4 are inserted into grooves 9 of cam body 2 while refill 7 is moved backward drawing pen point 20 of refill 7 into head member 13. When rotary-cam mechanism 5 and refill 7 is set in outer sleeve 1, refill 7 is inserted into outer sleeve 1 from the forward end in a state where the rear portion of refill 7 is inserted into rotary cam 3, spring 6 is put on the forward portion of refill 7, then head member 13 is screwed on the forward end of outer sleeve 1 by which rotary cam 3, refill 7, spring 6, and head member 13 are set. Thereafter when cam bar 4 is inserted into outer sleeve 1 from the rear end of outer sleeve 1, cam bar 4 deforms inward by the elasticity of cam bar 4, which enables projections 8 of cam bar 4 to get over the rear portion 15 of cam body 2 and to enter grooves 9 of cam body 2 so that the cam bar can be set. In this case, cam bar 4 is deformed inward while the rear portion 15 of cam body 2 is deformed slightly outward, which facilitates setting cam bar 4. Therefore, since cam bar 4 is inserted into outer sleeve 1 from the rear side it is possible to form a clip 21 from the integral part of cam bar 4 (Fig. 1), or a decoration having a size larger than the outside diameter, or a knocking cap. In the present invention, cam body 2 may be provided with guide 10 as shown in Fig. 4 which guides projections 8₄ of cam bar 4 so that the projections are easily inserted into grooves 9 of cam body 2. Further, in the present invention, cam bar may be formed with slit or slot 11(Fig. 3(a) ), or cut 12( Figs. 5 and 6), which facilitates cam bar 4 deforming inward to get over rear portion 15 of cam body 2 to enter into grooves 9 of cam body 2. Slits 11 may be slits having one side open. This invention is not to be limited to the embodiment shown in the drawing and described in the description, which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.

Claims: A rotary-cam ball-point pen comprising an outer sleeve (1), rotary-cam mechanism means (5), said rotary-cam, mechanism means (5) comprising a cam body (2) inside said outer sleeve (1), a rotary-cam (3) engaging said cam body (2), and a cam-bar (4) engaging said rotary-cam (3), the rotary-cam ball-point pen further comprising writing refill means (7) inside said outer sleeve (1) having a rear portion inserted in said rotary-cam (3), said writing refill means (7) being biased toward said rotary-cam (3) by resilient means (6), said cam-bar (4) being constructed of a flexible material so that it can be deformed inward by applying a small radial force to facilitate assembly, characterized in that said rotary-cam (3) is provided with projections (16₃) being inserted into grooves (9) of cam body (2) and that cam-bar (4) is provided with projections (8₄) also being inserted into said grooves (9) of cam body (2). The ball-point pen according to claim 1, characterized in that said projections (8₄) are slidably inserted into said grooves (9) and that the number of grooves (9) does not exceed the number of projections (8₄). The ball-point pen according to claim 1 or 2, characterized in that said cam, body (2) includes guide means (10) for said plurality of cam-bar projections (8₄). The ball-point pen according to any of claims 1 through 3, characterized in that said cam-bar (4) includes at least a slot (11) to assist in assembling said cam-bar (4) in said cam body (2). The ball-point pen according to claim 4, characterized in that said cam bar (4) includes a cut-out around said plurality of projections (8₄) to make said plurality of projections (8₄) deflectable to facilitate assembly.

Inventors: KAGEYAMA SHUHEI, KAGEYAMA, SHUHEI
Applicants: KOTOBUKI & CO LTD, KOTOBUKI & CO., LTD.
Application year: 1991
Main classification: B43K24
IPC codes: B43K24