Abstract: A method for correcting an integral signal representing the integral of an input signal derived from an accelerometer to eliminate the effects of errors in the input signal comprises sampling one or more signals which bear a functional relationship with the errors and subjecting the samples to a correction algorithmic process. The processed results are integrated and used to correct the input signal integral. Relatively few samples may be taken at below the Nyquist rate at random or pseudorandom intervals to provide an acceptable quantitive estimate of the error in the integrated input signal.The samples are spaced throughout the integration period by defining window intervals and taking one or more samples randomly in each window interval. Apparatus to practice the method include an integrator for integrating the input signal and a sample and hold circuit for sampling the input signal.

Abstract: A current-to-frequency converter 12' (FIG. 3) for use with an accelerometer 10 comprises a storage capacitor 13 which receives the accelerometer current and develops a charging voltage, reset charging means 25 which delivers timed charges to offset the voltage by predetermined amount and voltage sensing means 14' which senses the charging voltage reaching positive or negative thresholds in order to initiate a reset and offsetting the voltage. The polarity of charging voltage at which reset is triggered determines that polarity threshold as being half the magnitude of the offset voltage but the opposite polarity threshold of greater magnitude so that the voltage on the reset capacitor avoids it.

Abstract: A load handling device for transferring ISO flat racks, containers or the like, to and from a support comprising two spaced lifting arms (11) pivotally connected adjacent their lower ends (at 9) to said support (13) and hydraulic rams (40,41) for rocking said arms (11) in a vertical arc, and an extension arm (53) pivotally connected to the end of each lifting arm (11) remote from its pivotal connection (9) to the support (13) and further hydraulic rams (55,57) for rocking each extension arm (53) about its pivotal connection to its lifting arm (11) through a vertical arc extending to either side of the longitudinal axis of the lifting arm (11).

Abstract: A lifting device for handling flat racks or containers fitted with ISO corner castings comprising a main support plate having a lifting pin projecting from one face for engagement in an end aperture in an ISO corner casting and a tubular support on the plate carrying a locking pin movable in a direction at right angles to the longitudinal axis of the lifting pin for connection in a further aperture in the side of the corner casting for holding the lifting pin firmly in the end aperture, a pivotal link on the plate for connecting it to a lift strap, and to a spreader bar. The invention preferably also incorporates a special device for varying the effective length of the lifting strap.

Abstract: A recovery and towing vehicle which has been specifically designed for transport in a freighter aircraft and must necessarily therefore be of low profile to fit within the cargo space of an air-transport vehicle comprising a main chassis (1) on which is mounted a cab (3) with a removable upper part (5) and a slewing crane (7) having an extendable boom (11), a winch (10) and spades (23) mounted in slideways (29). The vehicle also is provided with a traditional supported lift towing boom (25) but instead of being mounted for pivoting movement on the chassis (1), the boom (25) is mounted for generally vertical sliding movement. For this purpose, slideways (29) are provided on the inside of housing (31) for the spades and vertical movement of the boom (25) is under the control of the main crane boom (11) which can be connected to the boom (25) by a lift strop (41).

Abstract: An accelerometer system (FIG. 2) suitable for measuring low-frequency accelerations in inertial systems is also able to measure high-frequency vibrational accelerations which give rise to e.g. sculling effects in inertial platform arrangements employing three such accelerometer systems. The system comprises a low-frequency inertial quality force feedback accelerometer 10' and a high-frequency, e.g. piezo-electric, accelerometer 46. The output of h.f. accelerometer 46 is summed at 48 with the feedback signal from transducer 32' in the l.f. accelerometer feedback loop, the faster response of the h.f. accelerometer providing most of the feedback to balance the l.f. loop without significant displacement of mass 11'. Up to several hundred Hz the displacement of mass 11' and the feedback component from transducer 32' is only to overcome the error in the h.f. accelerometer signals and at higher frequencies the response of the h.f.

Abstract: An inertial platform accelerometer cluster (FIG. 1) comprises a cluster of gyro and accelerometer system triads disposed in a cluster housing 10 to detect motion along and about orthogonal x, y and z axes. The orthogonal accelerometer systems each comprises a pair of codirectional accelerometers e.g. 15x, 15'x having an operating bandwidth from 0 to several KHz mounted on the housing walls equidistant from a point 14, which represents a common center of percussion to all pairs, at the center of gravity of the cluster. The analogue output signals of each accelerometer pair are scaled, summed and differenced to provide `sum` and `difference` signals which represent respectively acceleration in the sensitive direction and angular acceleration about an orthogonal axis.

Abstract: A power transmission gearbox comprises an input shaft, output shaft and power take off shaft mounted in a housing, the housing being adapted for connection to the input and output shafts in two positions in each of which the power take off shaft is mounted in a different position relative to the input and output shafts while the input and output shafts occupy the same relative positions. The gearbox allows the power take off shaft to be mounted in a "high" or "low" position on a vehicle.

Abstract: A main frame assembly for a road vehicle comprises two parallel vertical side frames connected together by cross members. The frame members are preferably composed of hollow tubes welded together. The cross members are unbraced to provide tortional flexibility without loss of load carrying capacity.