H, E, WIMPERIS,
`ACGELEROMETER,
`APPLICATION FILED AUG, 12, 1910,
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`982,336.
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`Patented Jan, 24, 1911.
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`UNITED STATES PATENT OFFICE.
`HARRY EGERTON WIMPERIS, OF CHELSEA, LONDON, ENGLAND, ASSIGNOR OF CAE-
`HALF TO GEORGE KEITH BULLER ELPHINSTONE, OF LONDON, ENGLAND.
`ACCELEROMETER..
`
`982,336.
`
`| Patented Jan; 24, 1911.
`Specification of Letters Patent.
`Application filled August 12, 1910. Serial Mo. 576,808. |
`
`To all whom it may concern:
`.
`Be it known that I, Harry Earnron
`“Wimeenis, a subject of the King of Great
`Britain,. residing at 28- Rossetti Garden
`Mansions, Chelsea, London, England, have
`invented a new and useful Accelerometer, of
`which the following is a specification.
`The primary object of this invention is to,
`provide an improved instrument for meas-
`10
`uring the acceleration or retardation of a
`. vehicle, such as an automobile, a train, or a
`ship, but the instrument may be used for
`various other purposes, ¢. g. the determina-
`tion of gradients, of the super-elevation of
`the curve of a railway line, of the angle of
`list or roll of a ship, of the power or effi-
`ciency of an engine, and so on.
`The instrument consists essentially of a
`metallic mass delicately pivoted on its axis
`and’ having its center of gravity slightly
`removed from such axis.
`In order to check
`or damp the movements of the mass I place
`it in the field of a magnet which is prefer-
`ably arranged so-that a portion of the mass
`lies between the poles. The mass is con-
`veniently formed in the shape of a disk or of
`a portion of adisk. An index is moved by the
`movements of .the mass over a scale gradu-
`ated according to the purpose for which the
`instrument is to be used, and a light spring
`or gravitational control is arrangedto bring
`-the mass back to a zero position.
`In order that the movements of the mass
`may be unaffected by the tilting of its axis
`in a plane perpendicular to the direction in
`which the acceleration is to be meastired,
`I pivot upon a parallel axis a second eccen-
`tric disk or mass, fast with which is a pinion
`meshing with a pinion fast with the first
`mass, the movements of the two masses about
`their respective axés being equal.
`I place a
`light spring control on one of the bodies and
`so arrange them that
`the two centers of
`gravity lie normally in the plane containing
`the two axes and either both between the
`axes or both outside them.
`The accompanying drawings show an in-
`strument made in accordance with this in-
`9
`vention, Figure 1 being a plan and Fig. 2
`or approximately 1 in g/n.
`What I claim is:— .
`a side elevation with the casing in section.
`a is @ casing standing
`on three feet 5,
`1. In an accelerometer, the combination
`one of which is provided with a screw and
`of a pivoted mass havingits center of grav-
`milled head¢for leveling.
`ity slightly removed from its pivot, a sec-
`d@ is the mass or disk, preferably of cop-
`ond pivoted mass also having its center of
`55
`per, fast on an arbor e turning in fixed piv-
`gravity slightly removed from its pivot,
`
`ots f the center of gravity of the mass being
`eccentric to the pivots. Part of the disk
`lies between the poles of a magnet g which
`damps its movements.
`Fast on the arbor ¢ is a pinion 4 meshin
`with another pinion 7 fast on an arbor
`turning in pivots Z and carrying a mass m
`the center of gravity ofwhich is eccentric to
`the pivots, the movements of the two masses
`abouttheir respective axes being equal, while
`the centers o
`avity normally lie in the
`plane through the axes of the arbors e and
`&. A light spring n attached to the arbor e
`and to a bracket’ o tends to bring the disk
`back to its zero position. The mass m. car-
`ries an index p which moves over a gradu-
`ated scale
`gq.
`,
`risa brake adapted to lock the disk when
`not in use and actuated by a spring rod s.
`The result of having the moments of the
`two masses d and m equal about their re-
`spective axes is that forces in the plane con-
`taining these two axes do notaffect the read-
`ing of the instrument.
`.
`hen it is desired to use the. instrument
`to measure the acceleration of an automo-
`bile, for instance, it should be placed on the
`vehicle with the plane through the axes of
`the arbors e and & at right angles to the di-
`rection of motion and the leveling screw
`should be adjusted until the needle comes to
`the zero of the scale. If the vehicle is sub-
`ject to violent jolts it is well to check. the
`accuracy of this adjustment frum time to
`time during the run in order to make sure
`that
`the instrument. has not been moved
`from its original position. Any accelera-
`tion due to the propelling force can then be
`seen from the movement of the ‘needle.
`Manyapplications of this instrument will
`-occur to the engineer, for instance if the ac-
`celerometer register
`feet per second when
`going uphill and the speed remain constant
`then the gradient will be
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`1 a
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`20
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`25
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`3 o
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`35
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`40
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`45
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`50
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`In
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`sin,
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`105
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`gearing connecting the two masses, an index
`actuated by the movements of the masses
`and a spring control adapted to bring the
`index back to a zero position.
`2. In an accelerometer, the combination
`of a pivoted mass having its center of grav;
`ity slightly removed from its pivot, a second
`pivoted mass also having its center of grav- |
`ity slightly removed from its pivot, gearing
`
`Witnesses:
`
`982,836
`connecting the two masses, a magnet damp- 10
`ing their movements, an index actuated by
`the movements of the masses and a spring
`control adapted to bring the index back to a
`zero position.
`RRY.EGERTON WIMPERIS.
`? H. G. TIsDALL,
`L. G. WATKINs.
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