A control device for electronic apparatus is provided with a d.c. ironless motor coupled to a manually rotatable knob. As the knob is rotated a digital signal representative of the rotation is derived from the back e.m.f. of the motor.

The invention comprehends a pedal operated mechanism comprising a pedal, means for mounting the pedal for pivotal movement about a substantially horizontal axis (considered in one orientation of said mechanism) in a substantially vertical plane, an output means adapted for operative connection to a flexible cable element, connection means operatively connecting the output means and the pedal such that the output means will translate the cable element, when operatively connected thereto, in respo...

A compressed air operated dispenser for separating and dispensing small helical coil springs or other small elongate workpieces comprises a trough providing a dispensing chamber into which the workpieces can be introduced to form a loosely packed bed in the bottom part thereof. An air supply mechanism effects blowing jets of compressed air intermittently, in a downwards direction, into the bottom part adjacent one side of the trough such that the compressed air is caused to sweep over the interi...

A sheet element, such as a banknote or other document of intrinsic value, incorporating an optical authenticating device comprising a thin film element, preferably in the form of a strip, or thread disposed within the thickness of the sheet element and having known characteristics of spectral reflectance and transmittance, and wherein in the region of a least part of the thin film element the sheet element is formed with a pair of superposed windows between which the thin film element extends so...

Improvements are disclosed in the pattern cone of the magnetic compass as described and claimed in copending application 769409, Harold T. Lyman, Jr., now U.S. Pat. No. 4,132,113. Simpler apparatus for trimming the sensor outputs of the sine and cosine of the angle between the craft's actual heading and the desired heading, are described and claimed. As in the said copending application the basic apparatus consists of a magnetic compass containing a pattern having a specified relation of black-t...

A drainage device, in particular a catheter, provided with an inflatable balloon adjacent one end which is designed to be inserted into a vessel which is to be drained. This insertion end comprises two branches which are interconnected at their free ends by the inflatable balloon and which are arranged, in the uninflated state of the balloon, to extend substantially parallel to the longitudinal axis of the device and to constitute substantially no increase in the width or diameter of the device....

A hand-operated portable electric ignition device for the ignition of gas comprises within an insulating housing means for producing from a battery relatively high voltage alternating current pulses in response to the operation of a manually-operable switch, said means including a transistor oscillator circuit, rectifying means for rectifying the alternating current pulses for charging a capacitor and means arranged to conduct to provide for the discharge of the capacitor through the primary of ...

There is disclosed in the present application a traction device adapted to being mounted on a driving wheel tire of a vehicle for obtaining greater traction on ice or snow although the device may also be useful in certain types of mud. The device comprises four spring arms each including a textured traction portion positioned across the face of the tire tread. The device is quickly mounted over the tire by collapsing and spreading apart the tread portions to permit bringing the device into engag...

A transmission device includes a first element having rolling surfaces of revolution on a first axis, a second element having surfaces of revolution on a second axis intersecting the first axis at an acute angle equal to or slightly larger than an apex half-angle of each of a pair of generally conical surfaces on one of the elements. The rolling surfaces of both elements are symmetrically disposed axially on each side of the point of intersection. The second element is mounted such that its axis...

An acoustic interferometer is provided which makes use of the Fabry Perot principle and makes use of destructive interference to suppress unwanted wavefronts and width or frequency modulation to `swing` the interferometer acceptance angle in accordance with a preset or adaptive plan.