Not Applicable
Not Applicable
The present invention relates generally to tool casings and, more particularly, to air-tightly sealed split-shell casings, especially for motor driven pneumatic tools, including vacuum and non-vacuum sanding and grinding tools.
The background information discussed below is presented to better illustrate the novelty and usefulness of the present invention. This background information is not admitted prior art.
Power tools require a covering or casing to protect their electronic and/or moving components. Such tools would soon be ruined if used without some kind of protective covering, as the electronic and/or moving components of the tools are easily affected by dust and moisture. Depending on the size, shape, and power source of the tool, the tool's protective casing can be manufactured as one-piece or multi-piece covers. Presently, all pneumatic tools use single shelled casings because of the seal that is required for the vacuum and/or exhaust chamber. All electric tools whether they are a vacuum type tool or not utilize a split shell design. Electric vacuum type tools, however, are not very effective because their split shell casing can not completely seal their vacuum chamber.
The present Inventor realized that manufacturing pneumatic tools using only a one-piece air-tight shell created many problems. The size, number, shape, and complexity of each tool component must be designed to fit into the one-piece air-tight shell. Additionally, when designing a single shelled housing for a pneumatic tool, the process is restricted to the mold-ability of the housing. This means that each housing must be designed to provide for the housing to be able to be ejected from the mold in which it is formed. Therefore the look and feel of the tool might be compromised to provide for the housing to be moldable. This requirement complicates the design, manufacturing, and assembly processes, and, furthermore, results in a heavier and perhaps bulkier and less ergonomic than desired tool and increases costs.
These concerns prompted the present Inventor to design an air-tight split-shell protective casing for pneumatic and other tools. As described below, split-shell casings, made according to the principles of the present invention, provide for an air-tight seal between the split-shell sections. Moreover, the degree of shape complexity and the number of features of both the tool to be housed and its housing easily and cost-effectively can be increased when a two or more multiple pieces housing design is used in place of a single-shell housing. At the same time, the air-tight sealable split-shell housings, as taught herein, provide for a reduction in the design complexity of the housing and tool that is required by a single shell design to provide for a fit between the tool and the housing, thus, simplifying manufacturing and assembly, and reducing overall costs. These cost reductions enable the production of split-shell housed tools that are more affordable for all. Moreover, split-shell cased tools are able to have a higher power to weight ratio, thus, providing for smaller, lighter tools to accomplish the same tasks as single-shell cased tool counterparts. Additionally, split-shell casings, made following the principles of the present invention, are rigid, strong, and capable of withstanding harsh operating conditions. Split-shell cased tools are easy to hold and are ergonomic in that the casings reduce tool-produced vibrations that otherwise would be adsorbed by a user's hands.
It should be noted that the present invention resides not in any one of these features per se, but rather in the particular structure of the components and the combinations of the features herein disclosed that distinguishes the present invention. It will be shown that the casings made according to the principles of the invention provide a sealing means that securely attaches two half-shells of a two-section split-shell casing to each other, so that for all tools so cased, without or with vacuum capabilities, which vacuum may be self-generated or supplied from a central vacuum device, the multiple-part protective shell provides an air-tight seal. The addition of the sealing means of this invention to a split-shell casing effectively creates a sealed chamber that can be used effectively in both vacuum or exhaust sections of the tool.
All of these benefits are made possible by providing for a tool casing, comprising:
at least two casing sections so molded that once positioned about a tool to be encased and joined together at their sealing perimeters with seals therebetween form an air-tight casing for encasing a tool, where a groove is molded into the sealing perimeter of one casing section forming a grooved casing section, a seal is inserted into the groove. A protruding ridge that is molded into the sealing perimeter of the casing section that is to be joined to the grooved casing section is adapted for compressing the seal inserted into the grooved casing section providing for an air-tightly sealed casing when the two sections are joined.
Furthermore, wherein each of at least two casing sections is so contoured as to provide air-tightly sealable inner-casing compartments for receiving tool components to be encased and wherein opposing joining perimeters of the air-tightly sealable inner-casing compartments are adapted with the grooves and protruding ridges, respectively.
The components to be encased are contemplated to be tools, such as a pneumatic tool, such as a central or self-generating vacuum pneumatic tool.
Each casing section comprises a molded firm inner layer coated by an outer pliant overmolded layer, where the molded firm inner layer may comprise a firm plastic layer and the molded outer pliable overmolded layer may comprise a urethane overmolded layer.
And, where the air-tightly sealable inner-casing compartments may comprise a first air-tightly sealed molded chamber for accommodating an exhaust chamber, a second molded chamber for accommodating an exhaust tube and an inlet tub, and a second air-tightly sealed molded chamber for accommodating a vacuum chamber.
Additionally, there is provided a method for making a multi-shell casing, comprising:
providing for an air-tightly sealable, sectional casing comprising:
In order that these and other objects, features, and advantages of the present invention may be more fully comprehended and appreciated, the invention will now be described with reference to specific exemplar embodiments, which are illustrated in appended drawings, wherein like reference characters indicate like parts throughout the several figures. It should be understood that these drawings only depict preferred embodiments of the present invention and are therefore not to be considered limiting in scope. Accordingly, the manner of making and using the present invention will be described with additional specificity and detail through the use of the accompanying drawings, in which:
a is a perspective view of one section of a two-section split-shell, central-vacuum, pneumatic tool according to the principles of the present invention.
b is a perspective view of the opposing section of a two-section split-shell, central-vacuum, pneumatic tool, as illustrated in
a is a perspective view of one section of a two-section split-shell, self-generated-vacuum, pneumatic tool according to the principles of the present invention.
b is a perspective view of the opposing section of a two-section split-shell, self-generated-vacuum, pneumatic tool, as illustrated in
Successful o-ring joint design requires a rigid mechanical mounting that applies a predictable deformation to the o-ring. The seal is designed to have a point contact between the o-ring and sealing faces. This allows a high local stress, able to contain high pressure, without exceeding the yield stress of the o-ring body. The flexible nature of o-ring materials accommodates imperfections in the mounting parts.
In vacuum applications, higher mounting forces are used so that the ring fills the whole groove. Also, round back-up rings are used to save the ring from excessive deformation. As the ring feels the ambient pressure and the partial pressure of gases only at the seal, their gradients will be steep near the seal and shallow in the bulk (opposite to the gradients of the point contact.
One example of a common material of an o-ring is Buna-N (nitrile rubber), which is the most widely used type of o-ring. It is also one of the least expensive type of o-ring seals. Due to its excellent resistance to petroleum products, and its ability to be compounded for service over a temperature range of −65 to +275 degrees F. (−54 to +135 degrees C.), nitrile is the most widely used etastomer in the seal industry today. Nitrile compounds are superior to most elastomers with regard to compression set or cold flow, tear and abrasion resistance.
It should be understood that the drawings are not necessarily to scale. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.
The principles underlying the invention, especially as they relate to the production of multi-section split-shell casings or housings for use with a variety of tools, are presented herein. To better describe the invention, the appended drawings illustrate one preferred embodiment of a two-section split-shell power tool casing. Each section of a two-section split-shell power tool casing, as illustrated, complements its companion section. Once the tool or its components are installed into the compartment or compartments of a first section, the companion second section is joined to the first section. The two sections are sealed together using sealing means that provide for air-tight seals forming an air-tightly sealed split-shell tool casing. The seal is secure to the point that no particulate matter, oil, or air can escape from or get into the casing. Thus, the present invention provides air-tight sealed split-shell casings for housing tools, such as pneumatic tools, with or without vacuum. The invention teaches split-shell housings specifically designed to accept specifically designed seals that provide the air-tight sealing of the housing parts to each other, and the method that is used to manufacture such housings. The housings, as exemplified in the accompanying illustrations, are made of two sections or modules, manufactured through a low-cost molding method, and sealing means that include upper and lower seals, rubber seal, and o-ring. Each shell section of the split-shell is molded according to the requirements of the tool it is designed to house. Once the parts of the desired tool are incorporated into the split-shell sections, the sections are joined and air-tightly sealed closed by the conjunction of the seals that are inserted into the grooves of the sealing rims of one of the spilt shell sections and the protruding ridges formed on the sealing rims of the complementary spilt shell. Thus, not only are the seals present, but the protruding ridges that press into the seal assure a tight, secure seal is made. Heretofore, split-shell construction could not provide such an air-tight seal, thus there have been no pneumatic tools having air-tight split-shell housing. As mentioned above, split-shell air-tight seal housing provides for a reduction in the number and the complexity of a tool's components, as split-shell design provides greater flexibility in the internal design of the split-shell sections, thus, simplifying manufacture and assembly and a reduction of overall costs. Furthermore, the air-tight seal split-shell housed tool is rigid, strong, and capable of withstanding harsh operating conditions, and it is designed to be easy to hold and ergonomic in its ability to reduce any vibrations that would other wise be adsorbed by a user hands.
Thus there has been described the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. Those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Turning now to the drawings,
Also illustrated in
A third housing chamber, illustrated in
b, another perspective view, illustrates the opposing section of the two-section split-shell, central-vacuum, pneumatic tool, as illustrated in
Compressed air travels from a compressor through vacuum end cap 14 into inlet tube 12 towards the motor housing as depicted by the air-path arrows illustrated within inlet tube 12. The path traveled by exhaust air depends on the type of tool in the housing. For central vacuum (CV) and non-vacuum (NV) machines, exhaust air travels through vacuum adapter 6 to exhaust tube 4 into exhaust chamber 2. The exhaust air then travels thru a material that muffles the sound 48, such as a felt material, to exist the tool in the direction of arrow 20. Another commonly used muffler material is sintered bronze, which is a porous material that allows air to pass thru but traps particulates, or other material carried by the exhaust air. After passing through the muffler, the exhaust air exits the machine. The inlet air does not mix with the exhaust air, even though the inlet tube is located in the exhaust chamber to minimize the size of tool, as the inlet air is kept contained within the inlet tube. Upper seal 52, lower seal 56, rubber tube seal 54, and o-ring 58 together tightly enclose exhaust chamber 2 to prohibit air and oil leakage at any point where other shell sections are joined to the section enclosing exhaust chamber 2.
a, a perspective view, illustrates one section of a two-section split-shell casing designed for housing a known self-generated-vacuum (SGV) pneumatic tool indicated by dashed lines. The casing of the SGV model is molded to have two inner compartments, an upper chamber in which inlet tube 12 is positioned and a lower chamber that is motor-exhaust/vacuum chamber 10. As the upper chamber is not divided into two discrete chambers, upper seal 52, rubber tube seal 54, and o-ring 58 are not required. In SGV machines, as in CV machines, compressed air travels from a generator through vacuum end cap 14 into inlet tube 12 towards the motor housing as depicted by the air-flow arrows. Self-generated motor exhaust air travels through the motor housing and then through vacuum adapter 26 into lower exhaust/vacuum chamber 10 as shown by arrow 60 which causes air to be pulled from the upper chamber above the back-up pad 62 and into vacuum chamber 8 and out of the machine in the direction indicated by arrow 22. Lower motor-exhaust/vacuum chamber is sealed by top section 56b of lower seal 56, end section 56e of lower seal 56, bottom section 56d of lower seal 56, and another end section 56c of lower seal 56.
b, a perspective view, illustrated the opposing section of the two-section split-shell encased self-generated-vacuum pneumatic tool, as illustrated in
Upper seal 52 and lower seal 56 may be made from a range of inert materials that exhibit the desired sealing properties. One example of a common material that may be used for the seal is Buna-N (nitrile), which is thought to be the most widely used o-ring material. Other materials may be satisfactory as long as the exhibit the properties required to form an air-tight seal in the environment as described. The rubber tube seal may be made from natural rubber (an elastic hydrocarbon polymer) or from any synthetic rubber, as long as the rubber of choice has the physical properties required for forming an air-tight seal.
The foregoing description, for purposes of explanation, uses specific and defined nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. For example, the shape and size of the casing can vary to accommodate the shape and size of the tool to be encased. The size, shape, and composition of the seals can likely be chosen as required. The number of sections of casing and the number and compartments within the casing depend, also, on the tool that is to be encased. Thus, the foregoing description of the specific embodiment is presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Those skilled in the art will recognize that many changes may be made to the features, embodiments, and methods of making the embodiments of the invention described herein without departing from the spirit and scope of the invention. Furthermore, the present invention includes all the variation, methods, modifications, and combinations of features within the scope of the appended claims, thus the invention is limited only by the claims.
This application claims priority benefit to Application No. 61043820 filed Apr. 10, 2008.
Number | Date | Country | |
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61043820 | Apr 2008 | US |