Title of Invention

HEATING ELEMENT AND FRAME MEMBER

Abstract

The invention concerns a heating element and frame member therefor. A frame member (22) for securing to the end of a former (13A, 138) of a heating element (12) comprises an elongate U-sectioned member with substantially parallel arms (24) defining between them a gap (25) for closely receiving an edge of the former, the arms being formed with one or more locally outwardly deflected portions (30) defining between them a larger gap (26). A heating element comprises a former consisting of a sheet (13A, 138) of insulating material having side edges (16) and top and bottom edges, an elongate conductor (14) wound round the former between the side edges, at least one locating strip (20) of insulating material connected to the former and extending outside the wound electrical conductor intermediate of the side edges of the former and extending between the top and bottom edges, the top and bottom edges of the former being clamped between the arms (24) of respective top and bottom frame members (22) as above, and the locally outwardly deflected portion or portions (30) being aligned with elongate strip ends which are located therein.

Full Text

HEATING ELEMENT AND FRAME MEMBER This invention relates to a heating element for a toaster or the like and frame members for such an element. A heating element for a toaster comprises a former formed from a sheet of insulating material having two opposite parallel side edges provided with grooves spaced therealong and an elongate conductor wound spirally around the former so as to locate in the grooves in turn. The former is secured between U-sectioned frame members which are located over at least the two opposite end edges of the former and then clamped to secure them to the former. Occasionally the electrical conductor will break and, in order to prevent broken parts from flying away from the plane of the former, which could be dangerous, it is known for locating strips to be secured outside the conductor on each side of the former. These strips conventionally extend parallel to the side edges and are located intermediately of those side edges, being secured to the former by two eyelets intermediate of their ends. The ends of the locating strips are either left floating freely which is untidy or are clamped into the end frame members during the clamping of those members to the end edges of the former. Because the ends of the strips are not secured to the former except by the frame member it is difficult to locate the end edge of the former together with a plurality of strip ends into the narrow gap between the arms of the U-sectioned frame member. This process adds to the production time and expense. According to the present invention a frame member for securing to the end of a former of a heating element has a U-section with substantially parallel arms defining between them a gap for closely receiving an edge of the former, the arms being formed with one or more locally outwardly deflected portions defining between them a larger gap. The position(s) of the outwardly deflected portion(s) will align with the locating strip(s). With such a frame member, the frame member can be located on the former edge and the member clamped thereto without necessarily trapping the ends of the locating strips. If the ends are not trapped they can be easily manually pushed into the locally wider gaps and this provides sufficient location of those ends. In another aspect the invention provides a heating element comprising a former consisting of a sheet of insulating material having side edges and top and bottom edges, an elongate conductor wound round the former between the side edges, at least one locating strip of insulating material connected to the former and extending outside the wound electrical conductor intermediate of the side edges of the former and extending between the top and bottom edges, the top and bottom edges of the former being clamped between the arms of respective top and bottom frame members, each of the top and bottom frame members having its arms formed with at least one locally outwardly deflected portion the gap between the locally outwardly deflected portions being larger than the regular gap between the arms, and the locally outwardly deflected portion or portions being aligned with an elongate strip. In a further aspect the invention provides a method of assembling a heating element comprising a former consisting of a sheet of insulating material and an electrical conductor wound spirally round the former, there being at least one locating strip of insulating material connected to the former and extending outside the elongate conductor between opposite edges of the former, which comprises locating said opposite edges of the former between the arms of respective U-sectioned frame members, each frame member having substantially parallel arms defining between them a gap for closely receiving an edge of the former, the arms being formed with one or more locally outwardly deflected portions defining between them a larger gap, and locating the ends of the locating strips in the larger gaps. One embodiment of frame member and heating element, in accordance with the invention, will now be described, by way of example only, with reference to the accompanying diagrammatic drawings of which:- Figure 1 is a front view of a heating element, and Figure 2 is an underneath view of one frame member. A heating element 12 for a toaster is of generally planar construction, comprising a former 13 made of insulating sheet material around which is wound an electrical conducting element 14, the former being located and secured in a rectangular frame 15. The former 13 is formed in two parts 13a, 13b located side by side and each having parallel side edges 16 formed with a plurality of grooves 17, with the electrical conductor 14 wound spirally around each of the parts of the former in turn and located in the grooves. Locating strips 20 of insulating material, on each side of each former part extend substantially parallel to the side edges 16 intermediate those edges. Each locating strip is secured to the former, preferably by a single securing element 21, for example in the form of an eyelet about which the strip may be pivotable. The frame 15 comprises at least top and bottom frame members 22 and preferably side members 23. Each of the top and bottom frame members 22 is of substantially U-section with two arms 24 extending substantially parallel to one another and defining between them a gap 25 dimensioned to just comfortably receive a top or bottom edge of the former. According to the invention, each of the arms is locally deformed slightly outwardly at 30, in the regions where the locating strips will align, so as to provide a locally wider gap 26 between the frame arms in these regions. With this arrangement a top or bottom frame member can be easily located over the top or bottom edge of the former and the ends of the locating strips more easily fitted into the frame member. However this can be done without bothering whether or not the locating strip ends are trapped between the arms. If desired the strip ends could be pivotted out of the way during this operation. When so located the arms of the frame member are clamped together at a plurality of spaced positions as indicated at 31 to secure the frame member to the former edge. If an end of a locating strip has not been trapped in the frame member in this process, it is a simple matter to manually tuck the end into the enlarged gap 26 and this provides sufficient retention, although additional clamping could be used in this region if desired. The side frame members 23 are clamped over the ends of the top and bottom frame members and clamped thereto at at least two corners as indicated at 33. CLAIMS 1. A frame member for securing to the end of a former of a heating element comprising an elongate U-sectioned member with substantially parallel arms defining between them a gap for closely receiving an edge of the former, the arms being formed with one or more locally outwardly deflected portions defining between them a larger gap. 2. A heating element comprising a former consisting of a sheet of insulating material having side edges and top and bottom edges, an elongate conductor wound round the former between the side edges, at least one locating strip of insulating material connected to the former and extending outside the wound electrical conductor intermediate of the side edges of the former and extending between the top and bottom edges, the top and bottom edges of the former being clamped between the arms of respective top and bottom frame members, each of the top and bottom frame members having its arms formed with at least one locally outwardly deflected portion the gap between the locally outwardly deflected portions being larger than the regular gap between the arms, and the locally outwardly deflected portion or portions being aligned with an elongate strip. 3. A heating element according to Claim 2 in which each end of each locating strip is located in a said locally outwardly deflected portion without being clamped between said arms. 4. An element according to Claim 2 or Claim 3 in which the or each locating strip is connected to the former by a single securing member. 5. An element according to Claim 4 in which the or each locating strip can pivot about its securing member. A method of assembling a heating element comprising a former consisting of a sheet of insulating material and an electrical conductor wound spirally round the former, there being at least one locating strip of insulating material connected to the former and extending outside the elongate conductor between opposite edges of the former, which comprises locating said opposite edges of the former between the arms of respective U-sectioned frame members, each frame member having substantially parallel arms defining between them a gap for closely receiving an edge of the former, the arms being formed with one or more locally outwardly deflected portions defining between them a larger gap, and locating the ends of the locating strips in the larger gaps. A method according to Claim 6 in which the frame members are located on said edges and clamped thereto without bothering whether or not the ends of the locating members are located in the larger gap or gaps, and thereafter any free ends of the locating members are tucked into the gap or gaps without being clamped thereto. A frame member for securing to the end of a former of a heating element substantially as described herein with reference to the accompanying drawings. A heating element substantially as described herein with reference to the accompanying drawings. A method of assembling a heating element substantially as described herein.

Documents:

114-mas-1997-abstract.pdf

114-mas-1997-claims duplicate.pdf

114-mas-1997-claims original.pdf

114-mas-1997-correspondance others.pdf

114-mas-1997-correspondance po.pdf

114-mas-1997-description complete duplicate.pdf

114-mas-1997-description complete.pdf

114-mas-1997-drawings.pdf

114-mas-1997-form 1.pdf

114-mas-1997-form 26.pdf

114-mas-1997-other documents.pdf

114-mas-1997-pct.pdf