Load limiting hinge

• US 7,017,232 B1
• Filed: 05/06/2005
• Issued: 03/28/2006
• Est. Priority Date: 05/06/2005
• Status: Expired due to Fees

• Current Assignee: Thomas G. Priddy
• Original Assignee: Thomas G. Priddy
• Inventors: Priddy, Thomas G.
• Primary Examiner(s): Mah, Chuck Y.
• Assistant Examiner(s): Vogelbacker, Mark T.
• Application Number:
  US11/123,015
• Time in Patent Office: 326 Days
• Field of Search: 162/86, 162/22, 162/33, 162/81, 162/56, 162/78, 163/22, 163/55, 163/74, 163/75, 162/97, 163/43, 163/21, 163/62, 163/31, 162/89, 126190-194, 493/86
• US Class Current: 16/286
• CPC Class Codes: E05D 11/06 Devices for limiting the opening movement of hinges
• CPC Class Codes: E05D 11/1007 with positive locking
• CPC Class Codes: E05D 3/12 with two parallel pins and one arm
• CPC Class Codes: E05F 1/1276 for counterbalancing
• CPC Class Codes: E05Y 2600/00 Mounting or coupling arrangements for elements provided for in this subclass
• CPC Class Codes: E05Y 2800/684 Strength alteration by weakening, e.g. by applying grooves
• CPC Class Codes: E05Y 2900/308 for ovens
• CPC Class Codes: F24C 15/023 Mounting of doors, e.g. hinges, counterbalancing

Abstract

The load limiting hinge provides a rigid, essentially inelastic drop down door mounting structure when normal loads are placed upon the door, but includes an easily replaceable weak link or “mechanical fuse” which breaks or opens when excessive force is applied to the open door. The hinge assembly supports the drop down door with practically no deflection of the door or hinge assembly when normal loads are applied to the open door, but allows the door to drop from the horizontal when excessive loads are applied to the door, to preclude the tipping of an appliance to which the door is attached or the continued use of the door as a platform. The hinge assembly is particularly useful in oven door installations, serving to assure that hot articles atop the stove are not spilled due to tipping of the appliance or inappropriate access by small children.

Claims

1. A load limiting hinge, comprising:

a substantially rigid hinge post having a hinge plate attachment portion, a spring attachment end opposite the hinge plate attachment portion, said hinge post having hinge plate pivot and hinge plate locking holes defined therein;

said hinge post further including a hinge plate pivot limit fastener hole defined therein;

a substantially rigid hinge plate having a pivot attachment hole, a door arm attachment hole, and threaded mechanical fuse attachment hole defined therein;

said hinge plate having a pivot limit slot in the shape of an arc formed therein, the center of the arc of the pivot limit slot being located at the pivot attachment hole of said hinge plate;

a hinge plate pivot limit fastener extending through the hinge plate pivot limit fastener hole of said hinge post and the pivot limit slot of said hinge plate;

an elongate, substantially rigid door arm having a hinge plate attachment end with a hinge plate attachment hole defined therein;

a hinge plate pivot fastener extending through the hinge plate pivot hole and the pivot attachment hole, pivotally attaching the hinge plate to the hinge post;

a door arm pivot fastener extending through the door arm attachment hole and the hinge plate attachment hole, pivotally attaching the door arm to the hinge plate; and

a threaded mechanical fuse extending through the hinge plate locking hole and the mechanical fuse attachment hole, the fuse having a fracture stress so that the fuse immovably affixes the hinge plate to the hinge post under normal load, and fractures when an excessive load applied to the door arm exerts tensile stress to fracture the fuse and pivot the hinge plate about the hinge plate pivot fastener.

2. The load limiting hinge according to claim 1, wherein:

said hinge post has a hinge plate pivot attachment wall and a hinge plate locking wall substantially normal to the hinge plate pivot attachment wall, the hinge plate locking wall having a door arm extension side and a hinge plate attachment side opposite the door arm extension side;

said hinge plate has a mechanical fuse attachment lug extending substantially normal thereto, the threaded mechanical fuse attachment hole being defined in the lug; and

said mechanical fuse has a head positioned adjacent the door arm extension side of the hinge plate locking wall and a shank extending through the hinge plate locking wall and attachment lug, the shank being held in tension.

3. The load limiting hinge according to claim 1, wherein said hinge post has a hinge plate pivot wall and a hinge plate locking wall substantially normal to the hinge plate pivot wall, the hinge plate locking wall having a door arm and hinge plate clearance slot defined therein, said door arm and said hinge plate extending partially through the clearance slot.

4. The load limiting hinge according to claim 1, wherein said hinge plate pivot limit fastener defines a diameter, the pivot limit slot of said hinge plate having a first end wider than the diameter of said hinge plate pivot limit fastener and a second end narrower than the diameter of said hinge plate pivot limit fastener, the width of the pivot limit slot tapering from the first end to the second end thereof.

5. The load limiting hinge according to claim 1, wherein said mechanical fuse is selected from the group consisting of externally wrenched bolts, internally wrenched bolts, and bolts both externally and internally wrenched.

6. The load limiting hinge according to claim 1, wherein said mechanical fuse is formed of material selected from the group consisting of ferrous metal, non-ferrous metal, and plastic.

7. A load limiting hinge, comprising:

a substantially rigid hinge post having a hinge plate attachment portion, a spring attachment end opposite the hinge plate attachment portion, and hinge plate pivot and hinge plate locking holes defined therein;

said hinge post further has a hinge plate pivot limit fastener hole defined therein;

a substantially rigid hinge plate having a pivot attachment hole, a door arm attachment hole, and threaded mechanical fuse attachment hole defined therein;

an elongate, substantially rigid door arm having a hinge plate attachment end with a hinge plate attachment hole defined therein;

a hinge plate pivot fastener extending through the hinge plate pivot hole and the pivot attachment hole, pivotally attaching the hinge plate to the hinge post;

a door arm pivot fastener extending through the door arm attachment hole and the hinge plate attachment hole, pivotally attaching the door arm to the hinge plate;

a slider bar attachment arm extending from said door arm, the slider bar attachment arm having a slider bar attachment hole defined therein;

an elongate, substantially rigid slider bar having a door arm attachment end and a hinge post contact end opposite the door arm attachment end, the hinge post contact end slidably bearing against said hinge post;

a door arm attachment lug extending from the door arm attachment end of said slider bar, the door arm attachment lug having a door arm attachment hole defined therein;

a door arm and slider bar connection fastener disposed through said slider bar attachment hole of said door arm and through said door arm attachment hole of said slider bar; and

a threaded mechanical fuse extending through the hinge plate locking hole and the mechanical fuse attachment hole, the fuse having a fracture stress so that the fuse immovably affixes the hinge plate to the hinge post under normal load, and fractures when an excessive load applied to the door arm exerts tensile stress to fracture the fuse and pivot the hinge plate about the hinge plate pivot fastener.

8. The load limiting hinge according to claim 7, further including:

a spring attachment arm extending from the door arm attachment end of said slider bar, opposite said door arm attachment lug; and

a tension spring secured to said spring attachment arm of said slider bar and to the spring attachment end of said hinge post, urging said slider bar toward the spring attachment end of said hinge post.

9. The load limiting hinge according to claim 7, further including, a hinge plate pivot limit fastener extending through the hinge plate and the hinge post, the hinge plate pivot limit fastener and the door arm and slider bar connection fastener each being a rivet.

10. An oven with load limiting hinge, comprising:

an oven having an open front with a lower edge;

a drop down door disposed at the open front of the oven, said door having a lower edge;

a pair of hinge assemblies connecting the lower edge of said door with the lower edge of the front of said oven, each of said hinge assemblies comprising;

a substantially rigid hinge post having a hinge plate attachment portion and a spring attachment end opposite the hinge plate attachment portion, said hinge post further having a hinge plate pivot limit fastener hole defined therein;

a substantially rigid hinge plate, said hinge plate having an arcuate pivot limit slot defined therein;

a hinge plate pivot limit fastener extending through the hinge plate pivot limit fastener hole of said hinge post and the pivot limit slot of said hinge plate;

an elongate, substantially rigid door arm pivotally attached to the hinge plate, the door being attached to the door arm; and

a pivot fastener pivotally attaching a first end of the hinge plate to the hinge post and a threaded mechanical fuse having a fracture stress, the fuse immovably affixing a second end of the hinge plate to the hinge post under normal load, and fracturing when an excessive load is applied to the door arm and exerts tensile stress sufficient to fracture the fuse and pivot the hinge plate about the pivot fastener.

11. The oven according to claim 10, wherein:

said hinge post further comprises a hinge plate pivot attachment wall and a hinge plate locking wall substantially normal to the hinge plate pivot attachment wall;

said hinge plate further includes a mechanical fuse attachment lug extending substantially normal thereto; and

said mechanical fuse further includes a head positioned adjacent the hinge plate locking wall and a shank extending through the lug and held under tension.

12. The oven according to claim 10, wherein said hinge post has a hinge plate pivot wall and a hinge plate locking wall substantially normal to the hinge plate pivot wall, the hinge plate locking wall having a door arm and hinge plate clearance slot defined therein, said door arm and said hinge plate extending partially through the clearance slot.

13. The oven according to claim 10, wherein:

said hinge plate pivot limit fastener has a diameter; and

the pivot limit slot of said hinge plate has a first end with a width greater than the diameter of said hinge plate pivot limit fastener and a second end with a width less than the diameter of said hinge plate pivot limit fastener, with the width of the pivot limit slot tapering from the first end to the second end thereof.

14. A load limiting hinge, comprising:

a substantially rigid hinge post;

a substantially rigid hinge plate having a first end pivotally attached to the hinge post and having a second end;

an elongate, substantially rigid door arm pivotally attached to the hinge plate, the door arm having a door attachment end, the door arm pivoting between a closed position in which the door attachment end is substantially parallel to the hinge post and an open position in which the door attachment end is substantially normal to the hinge post, the door arm having a stop bearing against the hinge plate when the door arm is in the open position;

means for biasing the door arm in the closed position; and

a fuse bolt having a head, a shank, and a groove defining a narrow diameter fracture section in the shank adjacent the head, the fuse bolt rigidly attaching the second end of the hinge plate to the hinge post, the fuse bolt having a fracture stress defined by the fracture section so that the fuse bolt fractures when a tensile stress equal to the fracture stress is applied to the bolt by a load applied to the door arm, the hinge plate pivoting so that the door attachment end of the door arm pivots more than 90°

relative to the hinge post, the means for biasing being disabled.

15. The load limiting hinge according to claim 14, wherein the head of said fuse bolt has a socket defined therein adapted for receiving a torquing tool, the socket extending into the fracture section, whereby the fracture section is hollow.

16. The load limiting hinge according to claim 15, wherein the socket is hexagonal-shaped, the head being adapted for receiving an Allen wrench.

17. The load limiting hinge according to claim 15, wherein the socket is star-shaped, being adapted for receiving a star-shaped driver.

18. The load limiting hinge according to claim 14, further comprising means for guiding and limiting the pivoting of said hinge plate upon fracture of said fuse bolt.