Fan assembly

Claim 1

THE COMBINATION IN A FAN ASSEMBLY OF A ONE-PIECE FAN SPIDER OF SHEET METAL COMPRISING A GENERALLY CIRCULAR APERTURED HUB SECTION AND A PLURALITY OF SIMILAR GENERALLY RADIALLY EXTENDING CIRCUMAXIALLY SPACED ARMS FORMED INTEGRALLY AT INNER END PORTIONS WITH THE HUB SECTION, SAID HUB SECTION BEING APERTURED CENTRALLY AND HAVING AN INNER ANNULAR PORTION WITH FRONT AND REAR SURFACES AND WHICH EXTENDS APPROXIMATELY IN A RADIAL PLANE AND ALSO HAVING AN OUTER AND MARGINAL ANNULAR PORTION DISPOSED ABOUT SAID INNER PORTION, SAID INNER ANNULAR PORTION OF THE HUB SECTION COMPRISING INNER AND OUTER ZONES THE FORMER OF WHICH LIES ADJACENT THE HUB SECTION APERTURE AND IS OFFSET FORWARDLY WITH RESPECT TO THE LATTER, PARTS OF SAID MARGINAL PORTION OF THE HUB SECTION BETWEEN SAID ARMS BEING OFFSET FORWARDLY WITH RESPECT TO ADJACENT PARTS OF SAID INNER ANNULAR PORTION, EACH OF SAID ARMS BEING IN AN ANGULARLY TWISTED RELATIONSHIP ABOUT A RADIAL CENTER LINE WITH RESPECT TO SAID INNER PORTION OF SAID HUB SECTION AND EACH OF SAID ARMS HAVING A RELATIVELY WIDE CENTRAL PORTION SUBSTANTIALLY FLAT THROUGHOUT A SUBSTANTIAL PORTION OF ITS LENGTH AND RELATIVELY NARROW SUBSTANTIALLY FLAT OPPOSITE SIDE MARGINAL PORTIONS, EACH OF SAID ARM MARGINAL PORTIONS BEING OFFSET FORWARDLY WITH RESPECT TO THE ADJACENT ARM CENTRAL PORTION TO AN EXTENT EQUAL TO THE FORWARD OFFSET OF THE ADJACENT PART OF THE MARGINAL PORTION OF THE HUB SECTION BETWEEN THE ARMS AND FORMING A SMOOTHLY BLENDING AND CONTINUOUS JUNCTIN AT ITS INNER END WITH SAID ADJACENT OFFSET MARGINAL PART, AND A PLURALITY OF SEPARATE SHEET METAL FAN BLADES EQUAL IN NUMBER TO THE ARMS OF SAID SPIDER AND ATTACHED RESPECTIVELY TO FRONT SURFACES OF SAID MARGINAL PORTIONS OF SAID ARMS EACH IN RADIALLY SPACED RELATIONSHIP WITH THE HUB SECTION OF THE SPIDER.