Patents by Inventor Douglas D. Hamilton

Douglas D. Hamilton has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5377730
    Abstract: A load stabilizing means for elongated objects grasped at one end and held vertically comprising gravity induced signals to hydraulic power and control means to correct deviations of the axis of the longitudinal object from the vertical. The preferred embodiment applies the invention to felling heads on light carriers.
    Type: Grant
    Filed: November 2, 1992
    Date of Patent: January 3, 1995
    Assignee: Logging Development Corporation
    Inventor: Douglas D. Hamilton
  • Patent number: 5161588
    Abstract: A felling head having a combination tree accumulator and abutment apparatus which eliminates the need for additional grapple arms to secure accumulated trees thus simplifying and lightening the felling head.
    Type: Grant
    Filed: December 3, 1991
    Date of Patent: November 10, 1992
    Assignee: Logging Development Corporation
    Inventor: Douglas D. Hamilton
  • Patent number: 5129438
    Abstract: A boom mountable tree processing head that incorporates a number of improvements, one of which is the ability to process more than one tree at a time. To do this, there is an accumulator type grapple arrangement and/or the trees are longitudinally offset for processing so that their diameters are essentially the same where they are gripped by the tree feed means. The accumulator grapple disclosed has two sets of grapples spaced apart from one another longitudinally along the processor with the arms of one grapple set being longer than that of the other. The grapple with the shorter arms also serves to press the tree against an improved endless conveyor type drive that propels the trees endwise for processing. Another improvement is the endless drive that includes two spaced apart driven endless chains located respectively on opposite sides of the feed path and interconnected by a plurality of somewhat resiliently flexible shoes. The processing head is hydraulically operated.
    Type: Grant
    Filed: November 21, 1990
    Date of Patent: July 14, 1992
    Assignee: Logging Development Corporation
    Inventor: Douglas D. Hamilton
  • Patent number: 5044409
    Abstract: A tree shear where the shear blade is moved by a power mechanism that includes a link and lever so arranged that the force available matches approximately, at all times, the force required to pass the shear blade through the tree to sever the same.
    Type: Grant
    Filed: October 29, 1990
    Date of Patent: September 3, 1991
    Inventor: Douglas D. Hamilton
  • Patent number: 5026248
    Abstract: A swing damper and a swing damper in one or more pivot joints, suspending a work tool such as a grapple from a boom. The swing damper is a hydraulic pivot joint where pivoting at the joint causes movement of a piston, in a closed chamber, that separates the chamber into first and second inter-related variable volume chamber portions. Upon movement of the piston, fluid is forced through a restricted opening from one chamber portion to the other with the amount of restriction determining the degree of damping. The piston is moved linearly in the chamber by a motion translating means operatively interconnecting the pivot shaft and piston. The motion translating means preferably is a screw thread on the shaft mating with a threaded aperture in the piston. Rods pass through the piston preventing it from rotating in the chamber.
    Type: Grant
    Filed: August 4, 1989
    Date of Patent: June 25, 1991
    Assignee: Logging Development Corporation
    Inventor: Douglas D. Hamilton
  • Patent number: 5004026
    Abstract: An improved tree felling head that minimizes splintering of the butt ends of trees while felling them, and that also minimizes losing them off the felling head after they are cut. The felling head has retaining means for loosely retaining the trees cut or being cut within tree receiving cradles provided on the felling head.
    Type: Grant
    Filed: October 6, 1989
    Date of Patent: April 2, 1991
    Inventors: Charles MacLennan, Douglas D. Hamilton, Robert M. Palfy
  • Patent number: 4717081
    Abstract: Apparatus for reducing to a smaller size residue or debris left behind after a tree processing or harvesting operation wherein the debris is dropped into a vertical assembly having a first reduction stage followed by a second reduction stage and below which there is mounted a fan or other conveyor means for delivering the reduced size of particles to a collecting container or other area. Being vertically oriented, there is self feeding from one unit to another and on the initial reduction unit, if desired, other impeller means can be utilized for infeeding the material to the cutters. The apparatus may be permanently mounted at a suitable location or, alternatively be mounted on a self-propelled mobile vehicle, movable from one location or another, and towing a trailer having a chip collecting container mounted thereon.
    Type: Grant
    Filed: September 6, 1984
    Date of Patent: January 5, 1988
    Assignee: Canadian Patents and Development Limited
    Inventor: Douglas D. Hamilton
  • Patent number: 4690185
    Abstract: A rim driven circular saw and a drive pinion rotatable about respective ones of a pair of spaced apart parallel axes wherein each of the saw and pinion having projections of gear tooth form about the outer periphery thereof with the teeth of one meshing with those of the other. The teeth on the saw each have a cutting edge set back from the normal intersection of the face and the top land of the teeth. The saw is journalled for rotation on a plate carried by a rigid frame and the plate has a thickness at least no greater than the kerf generated by the saw. The pinion is fabricated from a non-metallic substance such as nylon. Also disclosed is an accumulator type tree felling head incorporating, as the cutting device, a saw of the foregoing type.
    Type: Grant
    Filed: January 21, 1986
    Date of Patent: September 1, 1987
    Assignee: Logging Development Corporation
    Inventors: Douglas D. Hamilton, Robert M. Palfy, Hans Viereck
  • Patent number: 4593733
    Abstract: A tree felling head which includes a frame having a grapple mounted thereon with a grapple jaw which may be selectively opened and closed to respectively receive and grasp a standing tree and power means to selectively open and close the grapple; and a severing device mounted on said frame below said grapple for severing a standing tree. The severing device is a rim driven planar circular saw mounted around a peripheral portion thereof on an arm pivotally attached to the frame for movement in a plane transverse to the length of the standing tree, and included is a second power means for effecting rotation of said severing device.
    Type: Grant
    Filed: April 30, 1984
    Date of Patent: June 10, 1986
    Assignee: Logging Development Corporation
    Inventor: Douglas D. Hamilton
  • Patent number: 4004622
    Abstract: An apparatus for mounting on the free end of an extendible and retractable boom for handling trees comprising a first rigid frame assembly, a second frame assembly mounted on said first frame assembly at one end thereof and having a pair of arms pivotally mounted thereon, and a third frame assembly mounted on the opposite end and having a pair of arms pivotally mounted thereon. A further pair of arms are pivotally mounted on the third frame assembly and have cutting members for severing a tree. The apparatus provides a felling head having a pair of grapples spaced apart from one another longitudinally along a tree grasped thereby and a device for severing the grasped tree. Tree feed means is mounted on the first frame assembly for propelling a tree endwise between the arms of the second and third assemblies embracing such tree. The arms pivotally mounted on the second frame assembly have cutting edges for removing limbs from the tree as it is propelled endwise.
    Type: Grant
    Filed: December 30, 1974
    Date of Patent: January 25, 1977
    Assignee: Logging Development Corporation
    Inventor: Douglas D. Hamilton
  • Patent number: 3970124
    Abstract: A method and apparatus for marking and severing a tree trunk, such apparatus including a grapple for grasping a tree and a severing device spaced therefrom for severing the tree. A marking device is located at a position on the side of the grapple device opposite to that of the severing device and in selected spaced relation with the latter to effect a mark on the tree wherein a subsequent severing operation is to be effected. The spacing between the marking and severing device indicates the length of log to be severed. The marking device is actuated automatically upon effecting a severing operation such that during severing the mark is effected and which may be subsequently utilized visually to indicate appropriate positioning for the subsequent severing operation. Alternatively, automatic means may be utilized to detect the mark and such automatic detection actuating suitable means to effect the desired severing operation.
    Type: Grant
    Filed: June 27, 1975
    Date of Patent: July 20, 1976
    Assignee: Logging Development Corporation
    Inventor: Douglas D. Hamilton