Patent Application
20070163079
The present invention relates generally to molded handles. Specifically, it relates to an injection molded handle that efficiently uses material and is structurally sound, easier to produce, and is ergonomic, meaning it has a generally smooth lower surface, free from exposed ribs that provide discomfort to a user thereof when lifting heavier loads or any load for an extended period of time.
Prior art injection molded handles, for example on sewing machine covers, generally contain smooth top surfaces and oversized ribs along the underside. The smooth top surfaces provide a visually pleasing design. The oversized ribs provide additional strength necessary for proper handle operation. However, locating the ribs on the underside creates discomfort for users when carrying heavier loads, or even lighter loads for an extended period of time. Further, the ribs must be oversized, because the use of ribs as strengthening members on the lower portion of the handle is inefficient under bending loads. In an attempt to maintain the molding costs, prior art designs have been unable to eliminate the use of ribs on the underside without sacrificing strength or using more complicated molds, which may use cams and slides. Still further, other design features are necessitated in part by the molding process, such as providing a smooth top surface to provide a convenient and cost-effective location for injection mold gates. Consequently, it is desirable to have a design that efficiently uses material to provide a structurally sound and ergonomic molded handle that is easy to produce.
In one embodiment of the present invention, a molded heavy-duty ergonomic handle comprises: a top portion, the top portion extending in a longitudinal direction and being substantially smooth; and at least one U-shaped side channel having a plurality of ribs therein, the at least one channel having substantially smooth exterior surfaces and being located on a longitudinal side of the top portion.
In another embodiment of the present invention, a handled cover comprises: a handle, the handle having two opposing ends and comprising: a top member, the top member extending in a longitudinal direction between the two opposing ends and having a smooth top surface; and at least one U-shaped side channel having a plurality of ribs therein, the at least one channel having substantially smooth exterior surfaces and being located on a longitudinal side of the top portion; a first and a second base, each base being adjacent to one of the opposing ends of the handle; and a cover, the cover being adjacent to the first and second bases.
Referring to
Top portion 22 extends lengthwise (longitudinally) along the top of elongated handle 20 from either end 23 thereof. Generally, the lengthwise extension of portion 22 is smooth, or, in other words, devoid of any abrupt directional changes along the lengthwise extension that may significantly harm material flow during the molding process. Top portion 22 may be arc-like. Consequently, this top portion 22 provides a convenient and efficient location to place adjacently thereto within the mold a gate, which allows material to be injected into the mold cavity and is evidenced by surface irregularity 24, since the smooth contour of the extension promotes material flow into the mold cavity.
Side channels 26 may be located on either side of top portion 22, and may be generally U-shaped, comprising side walls 28, 30 and bottom 32. Side wall 28 extends down from top member 22 to bottom 32, while side wall 30 extends up from bottom 32. The U-shape efficiently provides strength, by having the bottom 32 extend laterally in a plane furthest from the neutral axis, to resist any bending moment generated from loads acting on ends 23. Also, the U-shape is ergonomically pleasing, as side wall 28 and bottom 32 have substantially smooth exterior surfaces, thereby providing ample surface area to comfortably support a user's hand when under load. This is contrary to prior art injection molded handles (not hollow or solid) that include ribs along the bottom surface, which provide limited and discontinuous surface area and cause the user discomfort as the ribs provide local areas of high pressure upon the user's hand. Ribs 34 may be included within channels 26, generally extending between walls 28, 30 as strengthening members. Finally, channels 26 may include an expanded portion 36 at either end 23 to provide added strength and reduce concentrated stresses at the junction between ends 28, 30 and bases 40 or an intended object 60.
Handle 20 may also optionally include web 38, located below top portion 22 and between side walls 28. The web 38 may be a series of discrete ribs or the like, as seen in
Handle 20 may be attached to any intended object 60 directly or indirectly, for example through the use of bases 40. Bases 40 allow handle 20 to mount away from object 60 to provide clearance for a user's fingers, thereby allowing the user to properly grasp handle 20. Base 40 may comprise a raised area 42 and a mounting surface 46. A contour may extend from raised area 42, which allows for a larger mounting surface 46 without requiring a larger raised area 42.
Handle 20 may exist independently, or may be integral or monolithic with base 40 and/or object 60. If handle exists independently, handle 20, base 40, and/or object 60 may be joined by any commercially known means, such as by welds, fasteners, or mechanical interference. If handle 20 does not exist independently, handle 20, base 40, and/or object 60 may be formed as a unitary piece by any commercially known method, such as by injection molding. Generally, handle 20, and base 40 and object 60, if integral or monolithic with handle 20, may be made form any commercially known moldable material, such as thermoplastics and metals.
The present invention allows molding of the entire handle 20 and any associated monolithic objects 60 via a single gate. As best seen in
Although the invention has been described herein with reference to the present embodiments, it will become apparent to those skilled in the art that various modifications of the present embodiments of the invention as described herein can be made without departing from the spirit or scope of the invention as defined by the appended claims.
