Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
2000-01-20
2003-04-29
Bryant, David P. (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C030S041000, C030S050000, C156S073200
Reexamination Certificate
active
06553641
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a razor having more than one shaving aid element.
BACKGROUND OF THE INVENTION
The incorporation of a shaving aid element in a disposable razor is often desirable. U.S. Pat. No. 4,170,821 (“'821 patent”) discloses a razor cartridge with a solid water-soluble shaving aid. The shaving aid can be a lubricant, whisker softener, razor cleaner, medicinal agent, aloe vera, vitamin E, lanolin, and other ingredients or any combination of these. A typical composition of a shaving aid element comprises a hydrophilic polymer and other soluble shaving aids such as those listed above being embedded in a matrix of a hydrophobic polymer. Typically, polyethylene oxide is used as the hydrophilic polymer and polystyrene is used as the hydrophobic polymer. Other compositions are also possible.
The beneficial effect of shaving aids in a disposable razor can be enhanced by incorporating more than one shaving aid element into a razor. A number of prior art patents disclose razors or razor cartridges incorporating two shaving aid elements. However, the disclosed shaving aid elements are positioned on the razor spaced apart from one another on different razor elements. For example, U.S. Pat. No. 5,524,347 discloses a razor cartridge with a first shaving aid element located on the upper surface of a cap member, behind the shaving blades, and a second shaving aid element positioned near the guard member of the razor, forward of the shaving blades. In U.S. Pat. No. 5,369,885, the shaving aid elements are attached respectively to the cap portion behind the shaving blades and to the seat portion forward of the shaving blades.
The beneficial effect of shaving aids in a disposable razor can be enhanced by incorporating more than one shaving aid element into a razor. A number of prior art patents disclose razors or razor cartridges incorporating two shaving aid elements. However, the disclosed shaving aid elements are positioned on the razor spaced apart from one another. For example, U.S. Pat. No. 5,524,347 discloses a razor cartridge with a first shaving aid element located on the upper surface of a cap member, behind the shaving blades, and a second shaving aid element positioned near the guard member of the razor, forward of the shaving blades. In U.S. Pat. No. 5,369,885, the shaving aid elements are attached respectively to the cap portion behind the shaving blades and to the seat portion forward of the shaving blades.
The separation of the shaving aid elements in these patents does not readily permit the benefits of one shaving aid element to be provided in conjunction with the benefits of the other shaving aid element. Thus, there exists a need for a feasible method of manufacturing shaving aid elements and securely coupling such elements to a razor in close proximity to one another.
Regardless of the exact chemical composition used for the shaving aid element, injection molding or extrusion can be used to manufacture shaving aid elements in quantities necessary for mass production. In injection molding, the shaving aid element is co-molded directly in the razor as shown in U.S. Pat. No. 4,778,640. In extrusion, the shaving aid element is extruded in the desired shape and then typically cut to size and secured to the razor as shown in U.S. Pat. No. 4,624,051 (“'051 patent”).
U.S. Pat. No. 5,956,848 (“'848 patent”), discloses an extruded shaving aid element that has a composite structure. The shaving aid element of the '848 patent consists of two shaving aid elements that are co-extruded. When secured to a razor cartridge, the composite shaving aid element presents two adjacent exposed lengthwise-extending portions. However, manufacturing such co-extruded structure can pose difficulties during assembly because in many situations, the two co-extruded elements may shrink at different rates during drying or curing and result in bending of the shaving aid element. To overcome this problem, the compositions of the two shaving aid elements may have to be modified with additives which may compromise the effectiveness of the shaving aids.
Another disadvantageous aspect of the composite shaving aid element of the '848 patent is its non-symmetric cross-sectional shape. The composite co-extruded shaving aid element of the '848 patent has a three-lobed Y-shaped first element with a second element co-extruded into the upper trough of the Y-shape. Such non-symmetrical shape complicates manufacture and limits the viable storage methods for the stock of shaving aid element before it is used in the razor manufacturing process.
Methods for securing the precut shaving aid element to the razor include mechanical means and adhesives. When mechanical means is utilized, the razor is made with an internal cavity and the shaving aid element is inserted into the cavity as illustrated in the '051 patent. A tab or any like member retains the shaving aid element in the cavity. The '848 patent also illustrates a shaving aid element that is mechanically locked into a razor cartridge. In the '848 patent, the shaving aid element has a ridge running along the bottom side of the shaving aid element which locks into a mating receiving portion of the cartridge. Disadvantages associated with such mechanical method include the need to precisely precut the shaving aid element to close tolerances and to form the shaving aid element from a material with suitable hardness and resiliency for such mechanical connection, as well as the added manufacturing expense and time of producing the tabs or like members. Furthermore, positioning the precut elements in the proper orientation and position for affixing to the razor complicates the manufacturing process.
When an adhesive, such as acrylate adhesive, is used, the shaving aid element and the razor must be properly positioned after the adhesive is applied and clamped together for a period of time to allow a bond to form. Although the curing time can be reduced by the application of energy, such as ultraviolet radiation, this adds another manufacturing step and increases production costs. Furthermore, the ultraviolet radiation may be absorbed or deflected by structural elements on the razor units, thereby preventing uniform curing of the adhesive. In any event, even accelerated cure time decreases manufacturing efficiency. Other disadvantages with adhesives are the added expense of the adhesive and the difficulties associated with the handling of adhesives.
The application of ultrasonic energy to join plastic components has been utilized in many industries. In ultrasonic welding, a solid-state power supply transforms electrical energy to 20 kHz or 40 kHz mechanical energy. A converter changes this electrical energy into ultrasonic mechanical vibratory energy. A horn transmits the ultrasonic mechanical energy directly to the parts to be assembled. A combination of applied force, surface friction, and intermolecular friction at the mating surface between the parts to be joined elevates the temperature until the melting point of the material is reached. Force is maintained after the vibrations cease and a molecular bond or weld at the interface is produced. A more complete discussion of ultrasonic welding is found in the following publications, which are hereby incorporated by reference: “Ultrasonics & Microprocessors Team-up for Efficient Assembly,”
Assembly Engineering
, November 1987, and
Ultrasonics Plastics Assembly
, 1979, published by the Branson Ultrasonics Corporation.
Ultrasonic welding has also been used in the shaving industry. For example, U.S. Pat. No. 5,070,613 describes a razor blade unit with a blade holder secured by a fixation strip ultrasonically welded to a lower portion of the razor blade unit. Further, it is well known to ultrasonically weld a head portion of a disposable razor to a handle portion. However, ultrasonic welding of a shaving aid element has not been suggested or disclosed in the art.
SUMMARY OF THE INVENTION
The present invention provides a method of manufacturin
Curello Andrew J.
Garland Colman C.
Johnson, III Barry C.
BIC Corporation
Bryant David P.
Pennie & Edmonds LLP
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