Overload arm for mold

Claim 2

In a blow modling machine wherein opposed blow mold havles are each pivotally mounted to swing between open and closed positions under the control of an associated power driven crank, the improved driving connection between each mold half and its associated crank which comprises a normally rigid but selectively resiliently yieldable link pivotally connected at its opposite ends to the power driven crank and to the mold half, said link comprising two rigid members pivotally interconnected at a point located intermediate said opposite ends of said link and lying slightly offset from a line interconnecting the pivot points at said opposite ends so that said members form a large obtuse angle at said joint, resilient means carried by said link for normally maintaining said members in a fixed angular relationship to each other at said joint during normal operation to transmit the motion of the crank to the mold half, but in the event of an obstruction which prevents the full closing of a mold half, said resilient means yielding to permit said members to pivot relative to each other to thereby permit a normal full stroke of the crank notwithstanding the shortened swing of the mold half.

Claim 3

In a blow molding machine wherein opposed blow mold havles are each pivotally mounted to swing between open and closed positions under the control of an associated power driven crank, the improved driving connection between each mold half and its associated crank which comprises: a first rigid link having a first end pivotally connected to the crank; a second rigid link having a first end pivotally connected to the mold half; the second ends of said first and second links being pivotally connected to each other at a resiliently yieldable joint, the axis of said joint normally lying slightly to one side of a line interconnecting the axes of said pivot connections at the respective first ends of said first and second links; said first and second links each having an abutment face adjacent said joint, and said links carrying resilient means for biasing said abutment faces into contact with each other to normally maintain said links in a constant angular relationship at said joint throughout the normal opening and closing cycle of the mold halves; in the event of an obstruction which prevents a full swing of a mold half to its closed position, said resilient means yielding to permit said abutment faces to separate and said links to pivot relative to each other at said joint, said joint thereby providing a lost-motion connection between the crank and the mold half in the event of an obstruction between the mold halves.

Claim 4

In a blow molding machine wherein opposed blow mold havles are each pivotally mounted to swing between open and closed positions under the control of an associated power driven crank, the improved driving connection between each mold half and its associated crank which comprises: a first rigid link having a first end pivotally connected to the crank; a second rigid link having a first end pivotally connected to the mold half; the second ends of said first and second links being pivotally connected to each other at a resiliently yieldable joint, the axis of said joint normally lying slightly to one side of a line interconnecting the axes of said pivot connections at the respective first ends of said first and second links; said first and second links each having an abutment face adjacent said joint, and said links carrying resilient means for biasing said abutment faces into contact with each other to normally maintain said links in a constant angular relationship at said joint throughout the normal opening and closing cycle of the mold halves; in the event of an obstruction which prevents a full swing of a mold half to its closed position, said resilient means yielding to permit said abutment faces to separate and said links to pivot relative to each other at said joint, said joint thereby providing a lost-motion connection between the crank and the mold half in the event of an obstruction between the mold halves.

Claim 5

The blow molding machine of claim 2, wherein said resilient means comprises a compression spring having means associated therewith for setting the force required to cause said yieldable joint to yield.

Claim 6

The blow molding machine of claim 2, wherein one of said first and second links carries means for adjusting the normal distance between said crank and mold half connections.