Patents Assigned to Donald MacMillan & Son, Inc.
  • Patent number: 4310374
    Abstract: This disclosure is directed to a tire retreading machine which includes a chamber adapted to receive therein a plurality of stacked tires adapted to be retreaded therein, the chamber having an inner surface, and inwardly therefrom there being a radiant heater, a porous or perforated shield, and an imperforate or nonporous shield with the latter being axially shorter than the former and both shields being spaced from a bottom surface of the chamber such that upon heat being generated by the radiant heater, hot air convection currents are set up within the chamber flowing generally upwardly adjacent the chamber inner surface and flowing generally downwardly between the imperforate shield and tires within the chamber to create substantially uniform curing or retreading temperature throughout the chamber, lessening temperature gradients or hot spots, and also allowing radiant heat to pass through a lower portion of the porous shield adjacent the bottom surface of the chamber to augment temperature uniformity thro
    Type: Grant
    Filed: June 16, 1980
    Date of Patent: January 12, 1982
    Assignee: Donald MacMillan & Son, Inc.
    Inventor: Kenneth T. MacMillan
  • Patent number: 4293293
    Abstract: A tire retreading bladder which includes a generally angular member of a U-shaped cross-sectional configuration defined by a bight portion and a pair of legs with the annular member defining an interior volume, each leg terminating in a terminal edge of a generally circular configuration, each leg having interior and exterior surfaces, a plurality of pairs of closely adjacent ribs along the exterior surfaces for venting air from between such exterior surfaces and an interior surface of an associated tire adapted to receive therewithin the bladder, each pair of ribs setting off a venting groove therebetween, and venting means further including transverse venting slots disposed lengthwise along the ribs.
    Type: Grant
    Filed: September 15, 1980
    Date of Patent: October 6, 1981
    Assignee: Donald MacMillan & Son, Inc.
    Inventor: Kenneth T. MacMillan
  • Patent number: 4245971
    Abstract: A molding machine in which first and second mold bodies which defines a chamber in a closed position thereof are carried by respective first and second supports and are moved along a predetermined path of travel with a locking post having a locking element being carried by a first of the supports and a second locking element being carried by the second support and being moved generally transversely to an axis of the locking post, the locking post having a threaded end portion and a nut rotatable thereon for axially adjusting the position of the locking post, and a stationary guide bar being embraced by a generally U-shaped guide element carried by the first locking element to prevent rotation of the locking post and the first locking element during the rotation of the threaded nut.
    Type: Grant
    Filed: October 18, 1979
    Date of Patent: January 20, 1981
    Assignee: Donald MacMillan & Son, Inc.
    Inventor: Kenneth T. MacMillan
  • Patent number: 4212605
    Abstract: The disclosure relates to a novel molding machine which includes the usual matrices and bead aligner wheels but additionally includes an expandable chamber adapted to receive a pressurized medium therewithin and thereby to expand and urge the matrices into intimate face-to-face engagement, together with locking means in the form of a plurality of locking slides for locking the matrices in intimate engagement.
    Type: Grant
    Filed: April 23, 1979
    Date of Patent: July 15, 1980
    Assignee: Donald MacMillan & Son, Inc.
    Inventor: Kenneth T. MacMillan
  • Patent number: 4197064
    Abstract: A tire retreading bladder of a generally annular configuration which is U-shaped in cross section as defined by a bight portion and a pair of legs, each terminating at an axially outwardly directed annular sealing bead and having at each terminal edge a plurality of circumferentially spaced valleys through which pressurized air may be introduced into and exhausted from the bladder, means disposed along each of exterior surfaces of the legs for venting air from between such exterior surfaces and an interior surface of an associated tire, and each exterior surface defining between radially inboard portions of each venting means and the associated sealing bead a generally smooth uninterrupted annular sealing surface adapted to form a hermetic line of sealing with an associated bead aligner wheel.
    Type: Grant
    Filed: May 2, 1979
    Date of Patent: April 8, 1980
    Assignee: Donald MacMillan & Son, Inc.
    Inventor: Kenneth T. MacMillan
  • Patent number: 4190405
    Abstract: This disclosure is directed to a heating device particularly adapted for tire treading and/or retreading matrices and includes a body having a continuously unending channel formed in an exterior peripheral surface of the matrix body in which is disposed an electric or steam heating element having opposite end portions in lapping relationship with the heating element being generally encased in a body of cast metallic material, and means in the form of a generally Z-shaped spacer traversing the channel and separating the solid material encasing the end portions on each other to permit the heating element to expand and/or contract.
    Type: Grant
    Filed: January 18, 1979
    Date of Patent: February 26, 1980
    Assignee: Donald MacMillan & Son, Inc.
    Inventor: Kenneth T. MacMillan
  • Patent number: 4172868
    Abstract: This disclosure relates to a method of retreading a tire by inserting a tire and an annular bladder between a pair of open matrices with marginal portions of the bladder projecting beyond beads of the tire and resting upon peripheral edge portions of axially opposed bead aligner wheels; the annular bladder being disposed within the tire; inflating the bladder to form an annular vacuum gap between an annular terminal edge of each bladder marginal portion, an annular outboard portion of each bladder and opposing annular portions of the bead aligner wheel peripheral edge portions; radially foreshortening the tire by moving the bead aligner wheels away from each other while the tire is held thereon by the bladder, and thereafter closing the matrices, and further inflating the bladder to urge the tire into intimate conformity with the matrices.
    Type: Grant
    Filed: June 27, 1978
    Date of Patent: October 30, 1979
    Assignee: Donald MacMillan & Son, Inc.
    Inventor: Kenneth T. MacMillan