Door Or Bulkhead Patents (Class 405/144)
  • Patent number: 8562254
    Abstract: The present invention provides a door arrangement for a tunneling machine. The door arrangement is for location at the front of the tunneling machine adjacent to the digging end of the machine. The door arrangement allows for the interior of the machine to be sealed off from the tunnel face, while also allowing for the door arrangement to be opened and allow complete access to the tunnel face. The door arrangement comprises door sections for hinged connection to a tunneling machine, the door sections being pivotable about the hinged connection between a closed position sealing the tunneling machine and an open position allowing the tunneling machine access to a tunnel face.
    Type: Grant
    Filed: July 31, 2009
    Date of Patent: October 22, 2013
    Inventor: Tony Dimillo
  • Patent number: 8523288
    Abstract: An opening for a replacement bit can be closed without a large drive force, the replacement bit can be replaced without being moved, and the workability of replacement is not impaired. A rear surface frame (29) forms a workspace (28) on the rear surface side of a spoke front surface plate (21), and openings (33) are formed on the spoke front surface plate (21) such that a replacement bit (31) can be inserted into and removed from the opening (33). A bit guide body (37) having a bit guide hole (38) is provided on the rear surface side of the opening (33). A gate plate (34) is provided which has valve ports (35) capable of communicating and closing the openings (33) and the bit guide holes (38). A gate opening/closing device (36) is provided which can turn the gate plate (34) to open or close the openings (33).
    Type: Grant
    Filed: June 3, 2010
    Date of Patent: September 3, 2013
    Assignee: Hitachi Zosen Corporation
    Inventors: Yasuharu Hanaoka, Kenji Sudoh, Isao Shimada
  • Patent number: 8342776
    Abstract: An explosive-resistant mine seal, which includes a pair of block walls. An adhesive is provided between adjoining surfaces of the blocks where the adhesive has greater strength properties than the blocks themselves. A core member is provided between the two walls and is bound thereto. The adhesive may be coated over the walls to increase the strength of the mine seal.
    Type: Grant
    Filed: June 6, 2008
    Date of Patent: January 1, 2013
    Assignee: Micon
    Inventors: George Anthony Watson, David A. Hussey, Stephen Gerard Sawyer
  • Patent number: 7665930
    Abstract: A hydraulic system has a hydraulic actuator for moving a door leaf of a door installation between open and closed positions thereof. A reservoir has a volume for containing a hydraulic fluid. A fluid circuit provides fluid communication between the hydraulic actuator and the reservoir. The system also has a pump for pumping hydraulic fluid from the reservoir into the fluid circuit to operate the actuator. A fluid circuit flushing system of the hydraulic system operates to flush a volume of hydraulic fluid from the fluid circuit back to the reservoir without moving any door leaves of the door installation. The hydraulic system may be part of a mine door installation installed in a mine passageway and having at least one door leaf. The hydraulic actuator is connected to the door leaf for driving movement of the door leaf between its open and closed positions.
    Type: Grant
    Filed: April 16, 2007
    Date of Patent: February 23, 2010
    Assignee: Kennedy Metal Products & Buildings, Inc.
    Inventors: William R. Kennedy, John M. Kennedy
  • Publication number: 20090010715
    Abstract: An explosive-resistant mine seal is provided, which includes a pair of block walls. An adhesive is provided between adjoining surfaces of the blocks where the adhesive has greater strength properties than the blocks themselves. A core member is provided between the two walls and is bound thereto. The adhesive may be coated over the walls to increase the strength of the mine seal.
    Type: Application
    Filed: June 6, 2008
    Publication date: January 8, 2009
    Inventors: George Anthony Watson, David A. Hussey, Stephen Gerard Sawyer
  • Publication number: 20080253841
    Abstract: A hydraulic system has a hydraulic actuator for moving a door leaf of a door installation between open and closed positions thereof. A reservoir has a volume for containing a hydraulic fluid. A fluid circuit provides fluid communication between the hydraulic actuator and the reservoir. The system also has a pump for pumping hydraulic fluid from the reservoir into the fluid circuit to operate the actuator. A fluid circuit flushing system of the hydraulic system operates to flush a volume of hydraulic fluid from the fluid circuit back to the reservoir without moving any door leaves of the door installation. The hydraulic system may be part of a mine door installation installed in a mine passageway and having at least one door leaf. The hydraulic actuator is connected to the door leaf for driving movement of the door leaf between its open and closed positions.
    Type: Application
    Filed: April 16, 2007
    Publication date: October 16, 2008
    Applicant: KENNEDY METAL PRODUCTS & BUILDINGS, INC.
    Inventors: William R. Kennedy, John M. Kennedy
  • Patent number: 6955594
    Abstract: A mine door of the present invention is adapted for installation in a mine passageway and includes a leaf adapted for swinging between a closed position and an open position. The leaf may be mounted in a frame, and a stopping wall may surround the frame. When closed, the leaf is subject to a differential in air pressure involving higher pressure on one of the faces of the leaf than on the other of the faces of the leaf. The leaf, the frame, or the stopping has an opening therein for passage of air therethrough from adjacent the one of the faces of the leaf to adjacent the other of the faces to more nearly equalize the pressure on the faces and thereby facilitate opening the leaf.
    Type: Grant
    Filed: June 27, 2003
    Date of Patent: October 18, 2005
    Inventors: William R. Kennedy, John M. Kennedy
  • Publication number: 20030118408
    Abstract: An earth discharging device, for a shield machine for constructing a tunnel in the vertical direction, has a pipe for discharging downwardly earth and sand that have been excavated by the machine as it advances upwardly. An elastic film-type valve is provided in the earth discharging pipe, which valve expands and contracts diametrically by means of fluid pressure to open and close the interior of the earth discharging pipe. A gate mechanism follows the elastic valve and adjusts the sectional area of the space through which earth and sand pass inside of the earth discharging pipe. The gate mechanism narrows the sectional area of the earth discharging pipe at the outlet side of the elastic valve so as to create a substantially uniform earth pressure upon the entire elastic valve to inhibit blockages and eruptions that might otherwise occur.
    Type: Application
    Filed: September 17, 2002
    Publication date: June 26, 2003
    Inventors: Hiroyuki Itou, Yuuichi Asai, Osamu Takagi, Kazuo Takamizawa, Fumio Kondou, Hidetoshi Sakamoto
  • Patent number: 6425820
    Abstract: A mine door system including at least two doors positioned in a mine passageway in spaced relation forming an airlock. The doors include at least one leaf movable between open and closed positions to allow passage into and out of the airlock. A control system controls operation of leaf movement actuators such that in normal operation, at least one door is always closed to control flow of air in the mine. A power source is included to effect movement of the leafs by the actuators.
    Type: Grant
    Filed: March 30, 2000
    Date of Patent: July 30, 2002
    Assignee: Jack Kennedy Metal Products and Buildings, Inc.
    Inventors: William R. Kennedy, John M. Kennedy
  • Patent number: 6334653
    Abstract: To move debris (6), the porosity of which presents certain properties, from a space subjected to the pressure of a compressible substance, such as air, where the pressure is high (pressure chamber, (1)) to a space (3) where the pressure is lower, the invention provides for an extraction chamber (2) to be positioned between the pressure chamber (1) and the space (3), which extraction chamber can be closed in relation to both spaces by means of slides (4 and 5). When the slide (4) is opened and the slide (5) is closed the extraction chamber (2) is filed with debris using the positive pressure in the chamber (1). After the slide (4) is closed and the slide (5) is opened the debris (7) contained in the extraction chamber (2) is evacuated from the chamber (2) into the space (3) by the pore pressure present in the debris.
    Type: Grant
    Filed: September 8, 1999
    Date of Patent: January 1, 2002
    Assignee: Wayss & Freytag AB
    Inventor: Wolfgang Puntke
  • Patent number: 6089791
    Abstract: To construct a tunnel in a formation (11, 15) with zones of high hydraulic pressure (15), a gallery (13) is driven from the stable formation (11) toward the problem formation zone (15). At least one lock zone (19) with pressure-tight gates (23, 23') is constructed under protection of the stable formation (11) at some distance from the problem formation zone (15). Behind this lock zone (19) the gallery (13) is now filled with water (25) and pressurized. Further driving into the problem formation zone (15) and therethrough is now performed under water (25) having a pressure corresponding to the hydraulic pressure of the problem formation zone (15). For this purpose the machines (47, 47', 73) are remote-controlled and are controlled and monitored from the atmospheric zone (17). Material transportation operations are managed substantially via the lock zone (19).
    Type: Grant
    Filed: September 1, 1998
    Date of Patent: July 18, 2000
    Inventor: Riccardo Bernasconi
  • Patent number: 5538362
    Abstract: A shield excavator for constructing a tunnel, a hole, a groove and the like having a polygonal, preferably, square section. The excavator (10) comprises: a cylindrical shield body (12) having a polygonal sectional shape; a cutter assembly (18) disposed at a front end portion of the shield body (12) so as to be reciprocatingly movable in a first direction intersecting at least the axis of the shield body (12); and a driving mechanism (16) for driving the the cutter assembly (18). The cutter assembly (18) includes: a plurality of serrated cutters (66) disposed at the front end of the shield body (12) at intervals in a second direction intersecting the axis of the shield body (12) and the first direction and extending in the first direction, or a plurality of plate-shaped cutters (68) disposed at the front end of the shield body (12) at intervals in the first direction and extending in the second direction.
    Type: Grant
    Filed: March 22, 1995
    Date of Patent: July 23, 1996
    Assignee: Kabushiki Kaisha Iseki Kaihatsu Koki
    Inventors: Toshio Akesaka, Kazuto Hamada
  • Patent number: 5203614
    Abstract: A tunneling machine convertible between a "closed mode" and an "open mode" of operation, having a rotatable cutterhead with muck openings communicating with a pressurizable cutterhead chamber and a pressure maintenance system to stabilize the tunnel workface when operating in the "closed mode". In the "closed mode" low slurry flow is employed as a liquid pressure balance solely to support the unstable tunnel face. Low slurry flow is supplied through a pressure bulkhead sealing the cutterhead chamber and pressurized conveyor means through the bulkhead removes tunneled material from the cutterhead chamber. A pressure lock connected to the pressurized conveyor means transfers tunneled material to dewatering and reservoir/accumulator means operated at substantially atmospheric pressure.
    Type: Grant
    Filed: June 17, 1991
    Date of Patent: April 20, 1993
    Assignee: The Robbins Company
    Inventors: Richard J. Robbins, David T. Cass, Peter B. Dowden
  • Patent number: 5180252
    Abstract: The invention relates to an earth pressure system shield process. First of all, an excavation additive consisting of the mixture of an agent for improving fluidity and viscosity of an excavated soil and a mud improving main agent is added (Ic, P.sub.2) to the excavated soil at the time of shield excavation at the working face, inside a mixing chamber (1b) of a shield machine (1) and inside a soil discharge screw conveyor (3) to sufficiently mix the excavated soil with the improving main agent and a mud improving assistant agent is then added (5) inside the soil discharge screw conveyor (3), so that the seal covered by the improving main agent so as not to be disssolved in water is removed chemically by this assistant agent. In this manner, the excavated soil is improved to a high quality soil having low fluidity inside the soil discharge screw conveyor (3) and is discharged.
    Type: Grant
    Filed: October 4, 1991
    Date of Patent: January 19, 1993
    Assignees: Kabushiki Kaisha Konoike Gumi, Kabushiki Kaisha Komatsu Seisakusho
    Inventors: Hiroshi Tanaka, Ryoji Kobayashi
  • Patent number: 5167474
    Abstract: A form for making a permanent mine stopping of pourable and hardenable material such as concrete. The form comprises two sets of elongate extension panels, each set including a plurality of panels which may be erected to extend vertically in side-by-side relation from the floor to the roof of a passageway in a mine. When erect, the two sets of panels form two generally vertical walls spaced from one another to define a space to be filled with a pourable and hardenable material to form the stopping. Each panel comprises a pair of elongate sheet metal members having a telescoping sliding fit with one another to permit adjustable extension of the panel to fit the height of the passageway. Tie bars hold the walls of the form in spaced, generally parallel relation prior to, during and immediately after filling of the space between the walls with the pourable and hardenable material.
    Type: Grant
    Filed: December 6, 1991
    Date of Patent: December 1, 1992
    Assignee: John Kennedy Metal Products & Buildings
    Inventors: John M. Kennedy, William R. Kennedy
  • Patent number: 5106163
    Abstract: A system for inspecting a forward end portion in a tunneling machine including cutter bits and a chamber such as a tunnel boring machine or a shield tunneling machine. The system includes an apparatus for inspecting a forward end portion comprising at least one through hole provided on the partition wall for defining a chamber, an elongate member slidably and rotatably inserted into the through hole, an image sensor positioned at a forward end of the elongate member for observing a cutter bit or the inside of the chamber, an image display provided in the main body for displaying an image from the image sensor, and a connection for connecting the image sensor and the image display. The system also includes a method for inspecting a forward end portion comprising the steps of defining a cavity in the chamber or in the vicinity of the cutter bits by supplying compressed air, inserting an image sensor into the cavity, and observing the inside of the chamber or the cutter bits using the image sensor.
    Type: Grant
    Filed: October 10, 1990
    Date of Patent: April 21, 1992
    Assignee: Obayashi Corporation
    Inventors: Toshio Fujiwara, Yukio Yamashita
  • Patent number: 4848963
    Abstract: The earth pressure shield for a tunnel and/or gallery excavator has a front working compartment formed by a separating wall having a digging tool and an annular reinforcing space substantially triangular in cross section positioned directly in front of the separating wall. So that an extensive restructuring of the machine is not necessary when moving from soft earth to hard ground, the annular reinforcing space is provided with a lower fluid feeder, a controlled upper pressurized air feeder, a plurality of fluid conductor pipes which are guided from below to an upper fluid outlet opening into the working compartment, and a fluid level controller. The invention is based on the consideration that a reliable and satisfactory support of the local front wall is only possible when the local front wall in the vicinity of the roof can be supplied with a fluid.
    Type: Grant
    Filed: February 18, 1988
    Date of Patent: July 18, 1989
    Assignee: Hochtief Aktiengesellschaft vorm. Gebr. Helfmann
    Inventors: Siegmund Babendererde, Hans-Jurgen Flunker, Gert Wittneben, Otto Braach
  • Patent number: 4846606
    Abstract: An excavated earth and sand transporting apparatus for use in a shield machine for carrying the earth and sand excavated by a cutter head mounted on the most front part of a shield proper through a screw conveyor followed by a transporting pipe to rearward of the shield proper. The excavated earth and sand transporting apparatus has an excavation discharging device mounted between the screw conveyor and the transporting pipe to discharge the earth and sand or the excavation conveyed by the screw conveyor into the transporting pipe while keeping a predetermined earth pressure inside the cutter head chamber so that the spouting of spring water can be prevented without having to use a bentonite slurry and/or a clay slurry and that the excavated earth and sand or excavation can be discharged efficiently and effectively.
    Type: Grant
    Filed: December 29, 1987
    Date of Patent: July 11, 1989
    Assignee: Kabushiki Kaisha Komatsu Seisakusho
    Inventor: Masao Fukada
  • Patent number: 4844656
    Abstract: The earth pressure shield contains a front working compartment having a digging tool and formed by a separating wall. An annular space is formed in the front working compartment with a top region connected with a regulated pressurized air feed and with a bottom region open to the digging tool so that dug or mined earth material is removable with the help of a conveyor unit. At least one fluid pipe is guided from a fluid chamber with a level controller and a fluid feeder to a fluid outlet open to the digging or mining tool in the working compartment. An especially reliable operation is attained when a bulkhead space is provided by partitioning behind the working compartment and/or the circular space formed with an immersed wall. This bulkhead space is connected in its upper region with the top region of the annular space by an opening in the separating wall and includes the fluid chamber in its lower region.
    Type: Grant
    Filed: March 30, 1988
    Date of Patent: July 4, 1989
    Assignee: Hochtief Aktiengesellschaft Vorm. Gebr. Helfmann
    Inventors: Siegmund Babendererde, Otto Braach
  • Patent number: 4732427
    Abstract: Apparatus for tunnelling through soil, in which a cutting head is rotatably mounted on a housing and atmospherically sealed from the housing. A muck ring is located in the housing to collect loose soil through an opening into the chamber of the muck ring and the opening is closable to maintain a pre-set earth pressure in the cutting head.
    Type: Grant
    Filed: September 17, 1986
    Date of Patent: March 22, 1988
    Inventor: Richard Lovat
  • Patent number: 4729693
    Abstract: The digging tool of the tunnel excavator is mounted on a shield support and operates in a forward digging chamber. The digging chamber is sealed from a tunnel formed by the excavator by a separating wall of the excavator across a transverse cross section of the excavator. The digging chamber is filled with a fluid which supports the forward digging chamber wall. The problems resulting from the incompressibility of the supporting fluid can be handled simply when the digging chamber, with at least a portion of its separating wall, is supported so as to be movable longitudinally back and forth by an adjustable spring device. Advantageously, the spring device comprises a plurality of hydraulic cylinder devices whose cylinders are connected to a hydraulic accumulator under gas pressure.
    Type: Grant
    Filed: September 18, 1986
    Date of Patent: March 8, 1988
    Assignee: Hochtief Aktiengesellschaft Vorm, Gebr. Helfmann
    Inventor: Volker Hentschel
  • Patent number: 4624605
    Abstract: Method for thrusting a shield for use in tunneling includes the steps of causing a rotary head, provided at the front portion of a shield body, an eccentric motion so that earth, soil or sand covering the front of the shield is pressed away radially of the shield, and exerting a thrust on the shield body during the eccentric motion of said rotary head. Apparatus for carrying out the method includes a driven crank shaft or a driven eccentric straight shaft, a conical or frustoconical rotary head supported rotatably by the crank or eccentric straight shaft, conveyor for discharging mined material backwardly, and hydraulic jacks for imparting a thrust to the shield body.
    Type: Grant
    Filed: March 30, 1984
    Date of Patent: November 25, 1986
    Assignee: Kabushiki Kaisha Iseki Kaihatsu Koki
    Inventor: Toshio Akesaka
  • Patent number: 4478535
    Abstract: A mine stopping having a man door and door frame assembly in which the mine stopping comprises a plurality of elongate extensible and contractible panels extending vertically in side-by-side relation from the floor to the roof of a passageway in a mine. Each panel comprises a first elongate member constituting the lower member of the panel and a second elongate member constituting the upper member of the panel. Each of the panel members has a web and flanges at opposite sides of the web, one of the members having a telescoping sliding fit in the other. The assembly comprises a rectangular frame having top, bottom and side channel members, the door being hinged to one of these. The frame is mounted in an opening in the mine stopping without any fastening means between the frame and stopping panels thereby maintaining the extensibility and contractibility of the panels.
    Type: Grant
    Filed: December 27, 1982
    Date of Patent: October 23, 1984
    Inventors: John M. Kennedy, William R. Kennedy
  • Patent number: 4456304
    Abstract: An earth removing apparatus for a shield tunneling machine comprising a tubular casing having an excavated earth inlet at one end and a closable outlet for excavated earth at the other end, and a double-shaft screw conveyor rotatably supported by the casing at two portions. The screw conveyor is supported on the casing in the vicinity of its earth inlet by an annular member fitted in an annular recess in the casing, with a bearing provided between the annular member and the casing. Since the forward end of the screw conveyor need not be supported at the center of rotation of the cutter head of the tunneling machine, the apparatus can be designed with greater freedom and is free of objections in its mechanical structure.
    Type: Grant
    Filed: May 27, 1982
    Date of Patent: June 26, 1984
    Assignee: Hitachi Shipbuilding & Engineering Co., Ltd.
    Inventors: Tadao Yoshikawa, Shoji Nishida
  • Patent number: 4406498
    Abstract: A method for excavating a tunnel wherein the muck from the tunnel face is admitted into the shield; the muck is pressed by a pressure of a predetermined level higher than an active earth pressure in the face and lower than a passive earth pressure as the shield body is moved forward, thereby establishing the balance between the earth pressure in the face ground and the muck pressure; and a liquid of a level balancing the underground water pressure is used to resist the underground water, thereby preventing movement of the underground water, whereby the face is maintained stable; and when the muck pressure is raised over the predetermined level, the muck is discharged out of the shield.
    Type: Grant
    Filed: June 9, 1981
    Date of Patent: September 27, 1983
    Assignee: Kabushiki Kaisha Iseki Kaihatsu Koki
    Inventor: Toshio Akesaka
  • Patent number: 4370003
    Abstract: A temporary gas seal is provided in a gas level drift of an in situ oil shale retort system which includes a production region having a panel of retorts producing gaseous and liquid products and an adjacent retort preparation region where a panel of in situ retorts is being prepared for production. A portion of the gas level drift is connected to the active retorts for withdrawing off gas while adjacent portions of the gas level drift are being developed. Portions of the gas level connected to the active retorts are temporarily sealed by a gas isolation barrier to isolate workers from toxic off gas. The gas isolation barrier can be a bulkhead with one or more openings each sealed by a remotely removable seal, such as a flexible membrane, or a plate that can be remotely removed or opened to unseal such a bulkhead opening.
    Type: Grant
    Filed: October 31, 1980
    Date of Patent: January 25, 1983
    Assignee: Occidental Oil Shale, Inc.
    Inventors: Rudolph Kvapil, Thomas E. Ricketts
  • Patent number: 4368924
    Abstract: A driving shield having a shield shell and a transverse wall for defining a work chamber, and a removal arm pivotally journalled on the transverse wall. The removal arm has a removal tool for mining or removing a face wall which also delimits the work chamber. A pressure medium supply is provided for attaining a support pressure in the work chamber. Material worked away from the face wall is removed by a discharge conduit arranged essentially along the bottom of the shield shell. The work or material-removing arm is journalled on the transverse wall in the pneumatic pressure duct, and the pressure medium supply is embodied as a pneumatic conduit. A sealing medium application device is movably coupled with the work arm, and the delivery nozzle of the device is directed upon the immediate surroundings at the free end of the removal tool.
    Type: Grant
    Filed: April 23, 1981
    Date of Patent: January 18, 1983
    Assignee: Ed. Zublin Aktiengesellschaft
    Inventor: Manfred Nussbaumer
  • Patent number: 4332508
    Abstract: A shield arrangement used for tunneling and mining in which a work chamber has an open front side located at the work face from which material is to be removed in tunneling and mining operations. Pressure is admitted into the work chamber for supporting the work face against crumbling and collapse. The work chamber also has supporting elements for the work face, which are selectively movable into and out of an operative position in which they support the work face. These selectively movable supports serve to replace at least partially, the support provided by the pressure medium admitted into the work chamber. The chamber has a longitudinal axis normal to the open side of the supporting elements which may be in the form of plates.
    Type: Grant
    Filed: February 25, 1980
    Date of Patent: June 1, 1982
    Assignee: Philipp Holzmann Aktiengesellschaft
    Inventor: Wilfried Krabbe
  • Patent number: 4311344
    Abstract: In a shield-type tunneling machine, a pair of comb-type bit-plates are pivotally supported on a peripheral wall of each cutter slit provided in a cutter disc. In order to adjust a degree of opening of each slit as well as a cutting angle of the bits with respect to the facing, the bit plates are pivotally moved to an open position or a close position for opening or closing each slit, in association with the reciprocating motion of a slide shaft disposed in a hollow drive shaft which rotates the cutter disc.
    Type: Grant
    Filed: April 14, 1980
    Date of Patent: January 19, 1982
    Assignee: Kabushiki Kaisha Iseki Kaihatsu Koki
    Inventor: Toshio Akesaka
  • Patent number: 4254994
    Abstract: Method and apparatus for gaining access to an underground chamber is disclosed to utilize a pressurized pipe casing which defines a conduit for introducing compressed air to a drill, which drill is utilized to bore a rescue hole to an area of entrapped miners. Thereafter, access is gained to the area of entrapment and the drill pipe is utilized as casing defining a rescue shaft for providing ingress of rescue personnel and egress of entrapped miners.
    Type: Grant
    Filed: June 8, 1978
    Date of Patent: March 10, 1981
    Assignee: New Jersey Drilling Co., Inc.
    Inventor: Donald J. McBride
  • Patent number: 4203626
    Abstract: The articulated boom-dipper-bucket assembly is utilized in a tunnel boring machine of the type which includes a hollow cylindrical body with a front circular cutting edge and a central axis on which an excavator including the assembly is positioned. The assembly includes a base having a front face facing axially of the machine and being mounted on a bulkhead having siderails which are received in channels fixed to the body and extending parallel to the central axis. A piston and cylinder mechanism is associated with the bulkhead for reciprocating same in a direction parallel to the central axis. The assembly further includes a boom having one end pivotally mounted to the front face of the base at one side thereof and a second end positioned outwardly from the base, an elongate dipper member pivotally mounted at a first inner end to the second outer end of the boom, and a bucket-scoop having an inner edge and an outer cutting edge and being pivotally mounted to a second outer end of the dipper member.
    Type: Grant
    Filed: February 21, 1979
    Date of Patent: May 20, 1980
    Assignee: Zokor Corporation
    Inventor: Herman Hamburger