Coating implements with material supply – Solid material for rubbing contact or support therefor – Including means to advance material
Reexamination Certificate
2000-10-06
2001-10-09
Huson, Gregory L. (Department: 3751)
Coating implements with material supply
Solid material for rubbing contact or support therefor
Including means to advance material
C401S082000, C401S175000
Reexamination Certificate
active
06299369
ABSTRACT:
The present invention relates to a dispenser, in particular to a dispenser for a solid block or soft solid mass and especially for dispensing a cosmetic or toiletry or material for personal or household use.
BACKGROUND
A number of known containers (alternatively referred to as dispensers) for a solid block or soft solid mass, such as dispensers in particular, for cosmetic materials or toiletries or other materials for personal or household use, comprise a barrel having one end through which the material can be dispensed, that end being open for dispensing a solid block or closed by an apertured cap for dispensing a soft solid mass. A rotor wheel is mounted at the opposite end of the barrel, and is fixed to a threaded rod which extends axially within the barrel and engages a correspondingly threaded mounting in a follower, a piston located within the barrel. When the rotor wheel is rotated, the threaded rod is likewise rotated and engages with the corresponding threading on the mounting of the piston, thereby translating the rotational movement of the rod into axial movement of the piston.
The transverse cross section of the barrel is at the discretion of the producer, commonly being either round or oval. The rotor wheel has typically comprised a round wheel projecting through opposed windows in a skirt depending from the base of the barrel. An alternative type of rotor wheel, as described in U.S. Pat. No. 3,612,705 and subsequently in EP-A-713660, comprises a wheel having approximately the same transverse cross section as the barrel and mounted underneath the barrel. Such an arrangement is particularly suitable for a non-circular barrel and wheel, for example, an oval barrel and wheel, because rotation of the wheel out of and into alignment with the barrel provides a readily apparent and effective means to meter the solid block or soft solid mass of material out of the dispenser. In U.S. Pat. No. 3,612,705, U.S. Pat. No. 5,868,510 and EP-A-813829 there is also described the location of small round bosses on the top surface of the rotor wheel and complementary shallow sockets indented into the bottom surface of the base of the barrel to align the rotor wheel with the barrel on each turn of the wheel. The present inventors recognise that this has benefits not only during the dispensing operation, but also preventing the wheel and base to become misaligned during transportation of the dispenser before it is filled. However, the design described in U.S. Pat. No. 3,612,705 presents a number of difficulties in practice for its smooth and effective implementation. The barrel is often produced by injection moulding of a thermoplastic, and the gate into the mould is normally located at the bottom of the barrel. The residual excess plastic in the gate forms an irregular protuberance beneath the bottom surface of the barrel which can impair the smooth rotation of rotor wheel. The alignment of a small round boss with a corresponding shallow socket is comparatively difficult because even a small spacial displacement can result in misalignment. Furthermore, when the small round boss on the wheel is rotated into contact with the edge of the bottom of the barrel, the vertical displacement of the wheel from the barrel bottom in order to accommodate the boss must be achieved suddenly due to the sharp profile of the boss. This has a number of effects. Impact of the boss at the same point at the base of the barrel wall can cause damage to the wall or to the boss, and with repeated turnings of the wheel relative to the barrel can result in the boss being worn away, so that it ceases to be effective eventually to perform an alignment function. Because a round boss provides approximately a point contact with the wall of the barrel on rotation, the impact is sudden and the resistance to rotation great, so that wheel rotation encounters a sudden stiffness.
It is an objective of the present invention to mitigate or avoid one or more of the difficulties described hereinabove.
BRIEF DESCRIPTION
According to the present invention there is provided a dispenser for a solid block or a soft solid comprising:
i) a barrel having a first end through which the solid block or soft solid is dispensed, and an opposite end comprising a base wall defining an aperture and having a lower surface;
ii) a rotor wheel mounted beneath the barrel having a transverse cross-section similar to the barrel and a top surface contiguous with the lower surface of the barrel;
iii) a threaded spindle fixed to the rotor wheel and extending axially through the aperture in the base wall of the barrel;
iv) a piston within the barrel having a threaded mounting that engages the spindle and moves axially on rotation of the spindle;
in which,
v) one of the base wall of the barrel or the top surface of the rotor wheel carries a radially extending boss having an inwardly tapered profile and the other of the base wall or the top surface has an sump dimensioned to accommodate the boss and in which the boss is seated when the rotor wheel and barrel are aligned.
By the employment of a boss having an inwardly tapering profile, the contact is gradual between the boss and the surface which it encounters during relative rotation of the rotor wheel and barrel. This alleviates or eliminates at least some of the difficulties identified hereinabove for a round boss.
DETAILED DESCRIPTION
The present invention provides a dispenser for dispensing material in the form of a solid block or soft solid in which the material is propelled upwardly within a barrel by a piston that is axially moveable by engagement with a threaded spindle fixed to a rotor wheel mounted beneath the barrel, in which the base of the barrel and the top surface of the rotor wheel are aligned by seating a tapered boss on one of the barrel base surface or rotor wheel top surface into a corresponding sump in the other surface.
Preferably, the boss is located on the rotor wheel and the sump in the base of the barrel, at least partly because it is desirable to have a relatively stiff base for the barrel. By employing a hollow rotor wheel, it is possible to have a rotor wheel with a relatively flexible top surface that is contiguous with the base of the barrel and that is reinforced in the vicinity of its mounting into the barrel. This is particularly valuable, enabling the top surface to flex in the vicinity of the boss, particularly when the top surface is thinned in the vicinity of the boss. Such flexibility enables the surface of the rotor wheel to be displaced vertically away from the barrel base surface when the boss encounters the base. Especially in cooperation with the tapered profile of the boss, this minimises the resistance to the boss climbing onto and subsequently riding across the surface of the base. By easing the way in which the boss climbs onto and rides across the base surface, the risk of damage to the boss or to the surface of the base is reduced, thereby preserving the ability of the boss to perform its locating function.
On rotation of the rotor wheel relative to the barrel, the boss produces an audible sound, or click, as it drops into the sump, thereby providing an additional cue to the user that a unit volume of cosmetic material has been dispensed from the barrel. The tapered profile of the boss minimises the sound as it engages the base surface before it encounters the sump, thereby minimising the risk that a click could be heard before the sump is reached and thereby avoiding confusing the user as to the amount of material dispensed if he or she were to hear a premature click.
It is preferable to employ a plurality of boss/sumps, most desirably disposed symmetrically around the barrel base/rotor wheel. Many useful dispensers according to the present invention are oval in transverse cross section, and in such dispensers, it is preferable to employ two bosses/sumps located on the major transverse axis of the dispenser. Particularly preferable, the boss is located adjacent to the sidewall of the dispenser.
The boss in many preferred dispensers has a taper angle of from
Baines Roger Anthony
Bunce Martin Christopher
James Robert David
Jones Russell
Boxer Matthew
Huson Gregory L.
Prunner Kathleen J.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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