Patents Assigned to South African Invention Development Corporation
  • Patent number: 4151801
    Abstract: A railway truck suspension including a load-bearing member, a pair of wheelsets supporting the load-bearing member, each wheelset being self-steering, and means interconnecting the wheelsets such that they yaw in opposite sense, the interconnecting means comprising a pair of arms on each side of the longitudinal axis of the truck in its direction of travel, each arm being secured at one end to an axle-supported bearing on a wheelset to transmit moments to that wheelset and the arms on the same side of the longitudinal axis extending generally towards each other, and means coupling the other ends of the arms together to allow lost motion between these ends while transmitting rotation of either arm to the other arm.
    Type: Grant
    Filed: July 2, 1976
    Date of Patent: May 1, 1979
    Assignee: South African Inventions Development Corporation
    Inventors: Herbert Scheffel, Rowlen E. Von Gericke
  • Patent number: 4147448
    Abstract: A compaction roller assembly and a method of operating it. The assembly comprises a draw frame and a non-circular lobed compaction roller connected via its axle to the draw frame. The assembly has restraint means mounted on the frame which is slidably engageable during rolling with one or both of the roller ends, and the method involves slidingly engaging the roller ends during rolling with the restraint means, to restrain undesired movement of the roller relative to the frame.
    Type: Grant
    Filed: May 12, 1978
    Date of Patent: April 3, 1979
    Assignee: The South African Inventions Development Corporation
    Inventor: Brian S. Jeffery
  • Patent number: 4136620
    Abstract: A load-carrying railway truck having a longitudinal axis in its direction of travel and including at least one load-bearing member for supporting a load; a pair of live wheelsets supporting the load-bearing member, each wheelset being so mounted in the truck and having such a profile that it is substantially self-steering; means interconnecting the wheelsets to transmit yawing and lateral movements of either wheelset in the opposite sense to the other wheelset; and elastic elements suspending the load to the wheelsets, at least some of the elastic elements having a lateral stiffness in a direction transverse to the longitudinal axis of the truck which is lower than the stiffness provided by them in a direction parallel to the longitudinal axis.
    Type: Grant
    Filed: July 2, 1976
    Date of Patent: January 30, 1979
    Assignee: South African Inventions Development Corporation
    Inventors: Herbert Scheffel, Rowlen E. VON Gericke
  • Patent number: 4130809
    Abstract: This invention provides a transversely excited travelling-wave gas laser in which the excitation pulse is shaped by a pair of elongate electrodes, the separation of which varies along their length. The separation is ideally determined empirically. Preferably, the laser has a pair of main discharge electrodes having a constant separation between which the lasing discharge occurs, and a pair of timing electrodes electrically in series with the main discharge electrodes, the separation of which varies such that the discharge between the timing electrodes provides a sharpened pulse that arrives along the main electrodes in such a manner as to obtain a travelling wave laser discharge. The main and timing electrodes are preferably segmented. The separation of the electrodes is determined empirically by bringing successive portions of the main discharge electrodes into alignment and varying the separation of corresponding portions of the timing electrodes to obtain the required timing characteristics.
    Type: Grant
    Filed: January 31, 1977
    Date of Patent: December 19, 1978
    Assignee: South African Inventions Development Corporation
    Inventors: Victor H. Hasson, Hubertus M. VON Bergmann
  • Patent number: 4128336
    Abstract: This invention relates to an apparatus and a method for spectroscopically analyzing substances, by fluorescent or resonant detection. An atomic cloud of a reference element is generated by cathodic sputtering and irradiated with radiation emitted from a substance of unknown composition. Generation of the atomic cloud is ceased and the inherent radiation of the atomic cloud allowed to decay. Any fluorescent or resonant radiation of the atomic cloud is then detected to determine the presence or concentration of the reference element in the unknown substance. Further, the amount of background radiation is detected by determining the amount of radiation extant when the concentration of atoms in the atomic cloud has decreased to substantially zero. The invention also provides an abnormal glow discharge lamp having two or more windows, the lamp being particularly suitable for use with the apparatus. The lamp further has a hollow anode with a transverse planar cathode.
    Type: Grant
    Filed: August 16, 1976
    Date of Patent: December 5, 1978
    Assignee: The South African Inventions Development Corporation
    Inventor: Louis R. P. Butler
  • Patent number: 4114113
    Abstract: This invention relates to transversely-excited gas lasers, in which the gas may be at atmospheric or greater pressure and in which the gas is excited by means of a distributed electric discharge between two electrodes. The electrodes, which are preferably elongate, are such that an initial trigger discharge occurs between minor trigger portions of the electrodes which conditions the discharge gap between the electrodes resulting in a distributed, preferably glow-type discharge, between the major portions of the electrodes causing lasing action in the gas. The trigger discharge preferably generates electro-magnetic radiation of high intensity to cause volume photo-ionization of the gas. The electrodes may be composite in form, each having a trigger electrode and a main discharge electrode that are directly electrically connected to each other.
    Type: Grant
    Filed: June 2, 1976
    Date of Patent: September 12, 1978
    Assignee: The South African Inventions Development Corporation
    Inventors: Victor Haim Hasson, Hubertus Michael VON Bergmann
  • Patent number: 4102986
    Abstract: Nitrous oxide (laughing gas) is produced by continuous decomposition of ammonium and nitrate ions fed into an aqueous, strongly acid reaction liquor containing chloride ion as catalyst. N.sub.2 O and water are continuously removed.Preferred parameters areHydrogen ion 3 - 7 M, preferably, 4 - 6M, say 5-5.7M; chloride ion 0.05 - 0.45 M, preferably 0.05-0.3M, say 0.1-0.2M; nitrate ion 4-16M, preferably 8.5 - 15M, say 12-14.5M; ammonium ion 1M or more, preferably 4.5 - 9M, say 7 - 9M. temperature: above 80.degree. C, preferably 105.degree.-120.degree. C.The temperature is so maintained that the reaction liquor boils at the reaction temperature, the excess water being continuously removed by fractional distillation. The N.sub.2 O which is withdrawn overhead, is scrubbed with caustic alkali to remove chlorine contamination in the form of hypochlorite byproduct.The process offers a high degree of safety, flexibility and ease of control and can be carried out with inexpensive technical grades of ammonium nitrate.
    Type: Grant
    Filed: November 8, 1976
    Date of Patent: July 25, 1978
    Assignee: South African Inventions Development Corporation
    Inventors: Jakob Van Rouendal Smit, Panayiotis Hassiotis, Robert Armistead Hasty
  • Patent number: 4092084
    Abstract: A two-bladed semi-rigid type tilt hub teetering rotor for an autogiro. The otor has a spin-up condition in which it has an relatively small blade angle, and an in-flight condition in which the blade angle is relatively high. The rotor is adapted to alter automatically from its spin-up condition to its in-flight condition upon tilting of the hub at take-off.
    Type: Grant
    Filed: July 22, 1976
    Date of Patent: May 30, 1978
    Assignee: The South African Inventions Development Corporation of Scientia
    Inventor: Austin Barltrop
  • Patent number: 4067262
    Abstract: A railway truck having at least one load-bearing member supported on two live axle wheelsets and including symmetrical suspension structure for damping hunting of the truck and wheelsets, the structure for each wheelset connected to bearings on the wheelset and two rods pivotally connected at each of its ends to the sub-frames for diagonally interconnecting the wheelsets to couple the yawing and lateral movements of the wheelsets. The sub-frame may be rigid to transmit moments to the wheelset or it may be a pinned structure. The suspension is said to cause inefficient gearing between the wheelsets.
    Type: Grant
    Filed: April 7, 1975
    Date of Patent: January 10, 1978
    Assignee: South African Inventions Development Corporation
    Inventor: Herbert Scheffel
  • Patent number: 4067261
    Abstract: A damping suspension for a railway truck having load-bearing members supported on at least two live wheelsets which are self-steering and which are directly interconnected to couple their yawing movements in opposite senses. The wheelsets are self-steering in that they each have profiled treads of high effective conicity and each is suspended by resilient elements having a low elastic yaw constraint to the load-bearing members. The yaw constraints imposed by the resilient elements are lower than the steering forces generated on the wheelsets on curved track as a result of the tread profile. The coupling between the wheelsets takes the form of diagonally connected resilient members for ensuring that the wheelsets do not oscillate in phase with the load-bearing members to thereby damp any hunting oscillations that may tend to occur.
    Type: Grant
    Filed: July 2, 1976
    Date of Patent: January 10, 1978
    Assignee: South African Inventions Development Corporation
    Inventor: Herbert Scheffel
  • Patent number: 4035683
    Abstract: This invention provides a compact high voltage electric switch having a fast switching time. The switch comprises two spaced-apart main electrodes defining a breakdown gap, in which an insulating gas is present, and a trigger means in close proximity to the gap to provide electrically generated electro-magnetic radiation of high intensity which causes large-scale volume photo-ionization of the gas and thus breakdown of the gap. The trigger means may conveniently be one or more trigger electrodes, with a trigger discharge occurring between the trigger electrode and one of the main electrodes or between two trigger electrodes. In a preferred embodiment, the main electrodes are flat and the trigger means is a surface gap spark plug centrally mounted in one of the main electrodes, with the trigger discharge occurring between the spark plug and the main electrode in which it is mounted.
    Type: Grant
    Filed: June 2, 1976
    Date of Patent: July 12, 1977
    Assignee: The South African Inventions Development Corporation
    Inventors: Victor Haim Hasson, Hubertus Michael VON Bergmann
  • Patent number: 3989818
    Abstract: Influenza virus is purified, fractionated or concentrated in an aqueous medium, using a linear filamentary non-charged polymer, preferably polyethylene glycol, as an insolubilising agent, at a concentration not exceeding 5% by weight. Impurities and large virus particles can be fractionated off at PEG concentrations of say up to 1%. Phase separation is achieved most readily when assisted by ultra-centrifugation at low temperature between 0.degree. and 6.degree. C. Precipitation of the virus from dispersions of comparatively high concentration (say 600 HA units or more per ml.) results in intimately aggregated virus particles, which are easier to further purify, and which result in an improved vaccine. Novel concenrates of globular influenza virus are also described.
    Type: Grant
    Filed: October 4, 1974
    Date of Patent: November 2, 1976
    Assignee: South African Inventions Development Corporation
    Inventor: Alfred Polson
  • Patent number: 3987289
    Abstract: A method of processing a varying electrical function is disclosed wherein the varying function is related to a series of straight line segments located in end-to-end relationship with each straight line segment closely following a corresponding portion of the varying function and not deviating therefrom by more than a predetermined maximum value. A straight line segment ends and the next successive straight line segment starts at each point where a deviation in excess of the predetermined maximum value occurs. The information on the varying function from time to time as it develops is registered only at each point where a straight line segment ends and the next successive straight line segment starts.
    Type: Grant
    Filed: May 15, 1975
    Date of Patent: October 19, 1976
    Assignee: South African Inventions Development Corporation
    Inventor: Gordon L. Bredenkamp
  • Patent number: 3982828
    Abstract: Eye testing apparatus including a control unit having a control display panel having a number of distributed electrical lights adapted to be illuminated; and electrical connection means for connecting the control unit to a source of electrical energy; a remote scanner unit adapted to be electrically connected to the control unit, and including a scanner display panel provided with electrical lights, positioned corresponding to the lights on the control display panel, and which are adapted to be illuminated corresponding to the illumination of the lights on the control display panel, the scanner display panel also having a fixing light; and operation means for causing any one or more lights on the control display panel and the corresponding light or lights on the scanner display panel to be illuminated for observation by a person viewing the scanner display panel.
    Type: Grant
    Filed: August 7, 1975
    Date of Patent: September 28, 1976
    Assignee: South African Inventions Development Corporation
    Inventor: Bernard Nathan Woolf
  • Patent number: 3966346
    Abstract: A compactor which comprises a wheeled frame including a pair of laterally spaced ground wheels and a pair of laterally spaced links pivotally mounted on the frame about a common laterally extending pivot axis. A roller of non-circular cross-sectional profile is rotatably connected to the links about a laterally extending rotational axis spaced from the pivot axis. The roller is disposed between the wheels and is movable between an operative position in which it rests on and can roll along a surface supporting the wheels, and an inoperative position in which it is raised from the said surface and supported by the frame. Elevator means is provided on the frame and engageable with the roller whereby the roller is movable between its operative and inoperative positions.
    Type: Grant
    Filed: December 4, 1973
    Date of Patent: June 29, 1976
    Assignee: South African Inventions Development Corporation
    Inventor: Aubrey Ralph Berrange
  • Patent number: 3964998
    Abstract: A process for removing nitrogen from raw or settled sewage, comprising passing the sewage through a first stage in the form of an anoxic biological denitrification stage, through a second stage in the form of an aerated biological nitrification stage, through a third stage in the form of an anoxic biological denitrification stage, through a fourth stage in the form of an aeration stage to facilitate solids separation, through a solids separation stage to provide a clarified effluent and an active sludge, of recycling mixed liquor from the second stage to the first stage and of recycling at least portion of the active sludge to the first stage. The process adapted for the additional removal of phosphates by regularly wasting sludge, by aerating the fourth stage to maintain a dissolved oxygen concentration of at least 4 mg/l, and by controlling th sludge recycle rate to limit the sludge retention time in the solids separation stage.
    Type: Grant
    Filed: April 9, 1975
    Date of Patent: June 22, 1976
    Assignee: The South African Inventions Development Corporation
    Inventor: James Laing Barnard
  • Patent number: 3950110
    Abstract: A compaction assembly comprising a lobed roller and a draw frame; and the operation thereof. A pair of composite links interconnects the roller and frame, each being pivotally connected to the frame and comprising at least two constituent links pivotally interconnected, all of said pivotal connections having lateral axes. Bearing means on each composite link carries the roller which extends therebetween. The composite links act as guide means constraining and guiding rolling of the roller. The bearing means are mounted to be independently pivotable about two or more axes relative to the draw frame and so that the roller axis has vertical free movement subject to gravity. Bias means biasses constituent links of the composite links into positions inclined to each other and allows the roller axis resiliently damped free movement relative to the frame in opposite directions along the direction of rolling.
    Type: Grant
    Filed: April 16, 1975
    Date of Patent: April 13, 1976
    Assignee: South African Inventions Development Corporation
    Inventor: John Michael Clifford