GB2187944A

GB2187944A - A plunger arrangement for a liquid applicator

Info

Publication number: GB2187944A
Application number: GB08704127A
Authority: GB
Inventors: Yoshiomi Konose
Original assignee: Mitsubishi Pencil Co Ltd
Current assignee: Mitsubishi Pencil Co Ltd
Priority date: 1986-02-21
Filing date: 1987-02-23
Publication date: 1987-09-23
Also published as: IT1215364B; JPS62136281U; GB8704127D0; DE3705491A1; GB2187944B; FR2594717A1; FR2594717B1; IT8719449A0

Abstract

A plunger arrangement for a liquid applicator comprises a latch ring (4), a plunger cylinder (8), and a coil spring (9) assembled in an outer stem (5). The latch ring includes a longitudinal groove (1) and a transverse groove (2) (shown in Fig. 4) which are connected to each other to form an L-shaped cam groove and the plunger cylinder includes a projection (7) at an outer part thereof. The projection of the plunger cylinder is slidably engaged in the cam groove so that the projection may be releasably anchored in the transverse portion (2) thereby preventing accidental pumping movement of said plunger. <IMAGE>

Description

SPECIFICATION A plunger arrangement for a liquid applicator This invention relates to a liquid applicator, and more particularly to a plunger arrangement for a liquid applicator such as, for example, a cosmetic sprayer.

A plunger-operated liquid applicator can be accidentally knocked to cause liquid to be sprayed inadvertently. Various improvements have been proposed to guard against an accidental knocking but these proposed applicators are of complex design and difficult to manufacture and assemble and are thus expensive.

According to this invention, there is provided a plunger arrangement for a liquid applicator, comprising an outer stem having a forward end and a rearward end, a latch ring, a plunger and a coil spring, the latch ring being attached to the inside surface of the outer stem adjacent a rear end thereof, and including an L-shaped cam groove comprising an axially extending longitudinal groove and a circumferentially extending transverse groove having one end connected to the rear end of the longitudinal groove, the plunger cylinder including a flange at its forward end, and a projection on its outer surface intermediate its ends and which is slidably engaged in the cam groove in the latch ring, the coil spring being interposed between the flange of the knocking cylinder and said latch ring, whereby the projection may be moved into said transverse groove to prevent depression of said plunger.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figures 1 to 3 show a longitudinal part section view of the rear end of a liquid applicator, wherein Figure 1 shows the applicator with the plunger cylinder locked when the liquid applicator is not in use; Figure 2 shows the applicator with the plunger member at the beginning of a pump action; Figure 3 shows the applicator with the plunger in its forwardmost position; and Figure 4 shows the development of the inner surface of the latch ring of the plunger arrangement.

Referring to the Figures, a hollow plunger cylinder 8 is slidably received in an outer stem 5, and a latch ring 4 is secured within the free end of the stem 5. Referring to Fig. 4, the inner surface of the latch ring 4 includes an L-shaped cam groove 3 comprising a longitudinal groove 1 extending in an axial direction and merging at its rear end with a transverse groove 2 which extends in a circumferential direction.

The latch ring 4 is fixed to the rear end of the outer stem 5 and the plunger cylinder 8 is received in the outer stem 5 via said latch ring 4. The plunger cylinder is open at its front end and closed at the rear end.=The plunger cylinder includes a flange 6 at its front end and two diametrically opposed projections 7 on its outer surface partway between its ends. In this description, the front end of the plunger cylinder is to be taken to mean that end which in use contacts the inner stem 11, i.e. the left hand end as viewed in Figs. 1 to 3.

The arrangement of the plunger cylinder 8 and the latch ring 4 is such that the projections 7 slidably engage the cam grooves 3.

A coil spring 9 is located between the front face of the latch ring 4 and a rearward face 9a of the flange 6 of the plunger cylinder 3.

The front end of the coil spring 9 is fastened to a small projection 10 which is provided rearwardly adjacent the rearward face 9a of the flange. The length of the coil spring 9 is designed so that when the projection 7 of the plunger cylinder 8 is at position B (Fig. 4) in the longitudinal groove 1 which is in the longitudinal groove 1 immediately adjacent the transverse groove 2, the spring 9 is in an equilibrium condition.

The outer stem 5 houses an inner stem 11 disposed to the front of the plunger cylinder 8 and a second coil spring 12 is located between the plunger cylinder 8 and the inner stem 11.

The second spring functions to maintain a clearance between the rear end of the inner stem 11 and the front face of the plunger cylinder 8 by preventing backward movement of the inner stem 11 when the projections 7 of the plunger cylinder 8 are engaged in the transverse grooves 2 of the latch ring 4.

In this condition, the inner stem 11 is prevented from being moved, and is protected against forward movement by setting the elasticity of the second spring 12 to exert a spring function even when the projections 7 of the plunger cylinder are moved to position B in the longitudinal groove 1 of the latch ring. The inner stem cannot be restored due to the compression of the coil spring 9.

During the plunging or pumping operation, the projections 7 of the plunger cylinder 8 are slidably moved back and forth between the positions B and C in Fig. 4. The pumping movement of the stem 11 begins when the projections 7 of the plunger cylinder 8 are at position B (Fig. 2), and ends when the projections reach position C (Fig. 3) which is the limit of forward movement. The pumping action is transferred from the plunger cylinder 8, via the front end to the rear end of the inner stem 11.

When the liquid applicator is not in use, the plunger cylinder 8 is moved slightly rearwards to move the projections 7 rearwards of the position B in the longitudinal groove 1 of the latch ring 4, and the plunger cylinder is then turned to move the projections 7 to position A.

Thus, the projections are anchored to engage the front side walls 2a of the transverse grooves 2 under the influence of coil spring 9 (Fig. 1), to render the arrangement inoperative.

When the liquid applicator is to be used again, the plunger cylinder is returned to the original pumping condition by turning the cylinder so that the projections are moved into alignment with the longitudinal grooves 1. The projections 7 are inherently moved to position B due to the coil spring.

The plunger arrangement of the liquid applicator as described above can be produced and assembled cheaply and has the advantage that it prevents an accidental pumping operation when it is not in use.

Claims

1. A plunger arrangement for a liquid applicator, comprising an outer stem having a forward end and a rearward end, a latch ring, a plunger and a coil spring, the latch ring being attached to the inside surface of the outer stem adjacent a rear end thereof, and including an L-shaped cam groove comprising an axially extending longitudinal groove and a circumferentially extending transverse groove having one end connected to the rear end of the longitudinal groove, the plunger cylinder including a flange at its forward end, and a projection on its outer surface intermediate its ends and which is slidably engaged in the cam groove in the latch ring, the coil spring being interposed between the flange of the knocking cylinder and said latch ring, whereby the projection may be moved into said transverse groove to prevent depression of said plunger.

2. A plunger arrangement according to claim 1, wherein a second coil spring is provided between the rear end of the inner stem and the rear end of the plunger cylinder.

3. A plunger arrangement including an outer stem portion, a movable member mounted for reciprocal movement within said stem portion, a plunger member slidably mounted in said outer stem portion and having an end portion protruding therefrom, one of said outer stem portion and said plunger including a projection, the other including cam surface means arranged such that the plunger member may be releasably latched in a position spaced from said movable member.

4. A plunger arrangement according to claim 4, wherein a first spring acts to maintain said plunger member in said latched position and a second spring is arranged between said plunger member and said movable member acting to urge said members apart.

5. A plunger arrangement substantially as hereinbefore described with reference to and as illustrated in any of the accompanying drawings.