US 5,398,794 AGranted

Overheating protection device for rotational control apparatus

AssigneeHorton Industries, Inc.

InventorsDavid Walberg, Kent Carlson

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Abstract

A device (110) for protecting a clutch (C) against overheating from externally caused problems such as rapid cycling is disclosed including a heat conductive plug (120) sealed in an escape port (116) of a fitting (112) by fuse material (124) such as lead. The fitting (112) is threadably, sealably received in a bore (104) formed in the friction interface disc (12) of the clutch (C). The bore (104) is in fluid communication with the cylinder (30) of the clutch (10) which slideably mounts a piston (10) connected to the friction interface disc (12). Fluid pressure introduced into the cylinder (30) by conventional conduits (42) moves the piston (10) therein against the bias of a spring (56) when fluid flow from the cylinder (30) through the bore (104) is blocked by the overheating protection device (110). When heat resulting from clutch temperatures exceeding normal operating temperatures and conducted to the fitting (112) and the device (110) is sufficient to melt the fuse material (124), the plug (120) is ejected from the escape port (116) by the fluid pressure communicated from the cylinder (30) to the bore (104). The fluid pressure of the cylinder (30) will be insufficient to move the piston (10) against the bias of the spring (56) when the escape port (116) is not sealed by the plug (120) and fuse material (124).

Claims20

Dependent claims

Device for providing overheating protection for an apparatus having a bore in fluid communication with fluid pressure, comprising, in combination:

a fitting formed of heat-conductive material, with the fitting having an axially inner end, an axially outer end, and an outer surface adapted for sealing receipt in the bore of the apparatus;
an escape port formed in the fitting and extending from the axially inner end to the axially outer end;
a tool bore for receipt of a tool for positioning the fitting in sealing receipt in the bore and adapted to locate the fitting totally within the bore, with the tool bore being of a radial size larger than the escape port and extending from the axially outer end of the fitting towards but spaced from the axially inner end of the fitting and axially in line with and in communication with the escape port;
a plug of a radial size smaller than the escape port and than the tool bore and of an axial length less than the escape port between the axially inner and outer ends;
and a fuse material having a first condition in a normal temperature range and a second condition when the normal temperature range is exceeded, with the fuse material sealing the plug in the escape port for sealing the escape port of the fitting in the normal temperature range but with the fuse material unable to hold the plug in the escape port under fluid pressure and for allowing escape of fluid through the escape port when the normal temperature range is exceeded, with the plug passing from the escape port into the tool bore and beyond the axially outer end of the fitting when the fuse material is unable to hold the plug in the escape port.

2 more elements

Dependencies are inferred from the claim text.