High strength blow-molded structure

A blow-molded plastic frame for a portable collapsible sign, the blow-molded plastic frame comprising:

• a first outer portion of the frame;
• a second outer portion of the frame that is spaced apart from the first outer portion, wherein a distance between the first and second outer portions is defined by a first height;
• a hollow interior portion disposed between the first and second outer portions;
• and
• a pattern of structural stiffening features integrally formed in the first and second outer portions, the pattern of structural stiffening features comprising:
• a plurality of first depressions extending from the first outer portion into the hollow interior portion, the first depressions disposed in rows and columns, each first depression including a first floor spaced apart from the first outer portion by a second height that ranges from about 7.5 millimeters to 11.5 millimeters, the first floor comprising three first arms having rotational symmetry, with each first arm rotated from another first arms by 120 degrees;
• and
• a plurality of second depressions extending from the second outer portion into the hollow interior portion, the second depressions disposed in rows and columns, each second depression including a second floor spaced apart from the second outer portion, the second floor comprising three second arms having rotational symmetry, with each second arm rotated from another second arms by 120 degrees,
• wherein the first floor of each first depression is aligned with the second floor of an adjacent second depression.

A blow-molded plastic structure having a hollow interior portion formed during a blow-molding process, the blow-molded plastic structure comprising:

• a first outer portion;
• a second outer portion that is spaced apart from the first outer portion, wherein the hollow interior portion is disposed between the first and second outer portions, and wherein a distance between the first and second outer portions is defined by a first height;
• and
• a pattern of structural stiffening features integrally formed in the first and second outer portions, the pattern of structural stiffening features comprising:
• a plurality of first depressions extending from the first outer portion into the hollow interior portion, the first depressions disposed in rows and columns, each first depression including a first floor spaced apart from the first outer portion, the first floor comprising a plurality of first arms, one or more of the first arms rotated with respect to an adjacent one of the first arms by a first angle;
• and
• a plurality of second depressions extending from the second outer portion into the hollow interior portion, the second depressions disposed in rows and columns, each second depression including a second floor spaced apart from the second outer portion, the second floor comprising a plurality of second arms, one or more of the second arms rotated with respect to an adjacent one of the second arms by a second angle,
• wherein the first floor of each first depression is aligned with the second floor of an adjacent second depression, and
• wherein the first floor of each first depression is spaced away from the second floor of an adjacent second depression by a fourth height that ranges from about 2 millimeters to 5 millimeters.

A blow-molded plastic frame for a portable collapsible sign, the blow-molded plastic frame comprising:

• a first outer portion of the frame;
• a second outer portion of the frame that is spaced apart from the first outer portion, wherein a distance between the first and second outer portions is defined by a first height;
• a hollow interior portion disposed between the first and second outer portions;
• and
• a pattern of structural stiffening features integrally formed in the first and second outer portions, the pattern of structural stiffening features comprising:
• a plurality of first depressions extending from the first outer portion into the hollow interior portion, the first depressions disposed in rows and columns, each first depression including a first floor spaced apart from the first outer portion, the first floor comprising three first arms having rotational symmetry, with each first arm rotated from another first arms by 120 degrees;
• and
• a plurality of second depressions extending from the second outer portion into the hollow interior portion, the second depressions disposed in rows and columns, each second depression including a second floor spaced apart from the second outer portion, the second floor comprising three second arms having rotational symmetry, with each second arm rotated from another second arms by 120 degrees,
• wherein the first floor of each first depression is aligned with the second floor of an adjacent second depression, and
• wherein the first floor of each first depression is spaced away from the second floor of an adjacent second depression by a fourth height that ranges from about 2 millimeters to 5 millimeters.