Braun Gmbh

Sven Schäfer

Marc Kunz

Kris Lueckel

Werner Huebscher

Stefan Gehard Triebig

A multi-component housing having a length and comprising at least a first component comprising a first plastic material, a second component comprising a second plastic material, and a third component comprising a third plastic material. The housing includes at least one tolerance-elimination element made of the second plastic material and longitudinally attached to the first component along the housing's longitudinal axis. The tolerance-elimination element has an average length extending parallel to the housing's longitudinal axis, which average length is at least ten times less than the length of the housing. The third component at least partially forms an outer surface of the housing, so that the tolerance-elimination element is at least partially overmolded by the third plastic material.

Multi-component plastic housing

A plurality of mass-produced identical multi-component housings for toothbrush handles, each housing having a length of about 120-200 mm, which is at least three times greater than a maximal orthogonal dimension thereof. Each housings includes at least a first component made of a first hard-plastic material, a second component made of a second hard-plastic material, and a third component made of a soft-plastic material, which are integrally joined together to form a generally tubular structure. Each housing includes a tolerance-elimination element made of the second plastic material, attached to one of first component's ends, at least partially overmolded by the soft-plastic material, and having an average length of about 3-20 mm, which average length varies among at least some of the tolerance-elimination elements by a lengthwise dimension that is at least ten times greater than the lengthwise maximal dimension variations of the length among the individual multi-component housings.

Plurality of mass-produced multi-component plastic housings

A plurality of mass-produced multi-component housings having a length and comprising at least a first component comprising a first plastic material, a second component comprising a second plastic material, and a third component comprising a third plastic material. Each of the housings includes at least one tolerance-elimination element made of the second plastic material and longitudinally attached to the first component along the housing's longitudinal axis. The tolerance-elimination element has an average length extending parallel to the housing's longitudinal axis, which average length is at least ten times less than the length of the housing. The third component at least partially forms an outer surface of the housing, so that the tolerance-elimination element is at least partially overmolded by the third plastic material. The tolerance-elimination elements of the plurality of multi-component housings are structured to cause lengthwise maximal dimension variations of the length L among the individual multi-component housings to be not greater than 0.1 mm.

A process for making a multi-component hollow housing comprises injecting a first plastic material into a first mold cavity and causing it to solidify to form a first component, whereby the first plastic material shrinks lengthwise; injecting a second plastic material into a second mold cavity having the first component transferred thereto and causing the second plastic component to solidify to form a second component, the second component comprising a tolerance-elimination element that is longitudinally attached to the first component at one of the ends thereof, wherein a length of the shrunk first component is at least ten times greater than a length of the tolerance-elimination element, and wherein an absolute lengthwise shrinkage of the second plastic material forming the tolerance-elimination element is at least ten times smaller than the lengthwise shrinkage of the first plastic material; at least partially overmolding an intermediate part comprising the first and second component with a third plastic material in a third mold cavity, thereby forming the multi-component housing in which the tolerance-elimination element is at least partially overmolded by the third plastic material, and wherein the third plastic material forms at least a portion of an outer surface of the multi-component housing; and removing the multi-component housing from the core.

Growing community of inventors

Hohenstein, Germany

Sven Schäfer