US2164588A - Indicating apparatus - Google Patents

Description

Patented .niy at, QS@

gaat A rNnrca'rrNe APPARATUS Don C. McRae, Miami, Fla., and John V0. Franklin, Kansas City, Mo., assignors to Eclipse Aviation Corporation, East Orange, N. J., a corporation of New Jersey Application March 16, 1936, Serial No. 69,232

4 Claims.

This invention relates to indicating apparatus and particularly to indicating the relationship between the rates of rotation of any two or more continuously rotating mechanisms such as ing ternal combustion engines installed on an airplane or other craft and subject to variations in speed.

An object of the invention is to provide an indicating system including a synchroscope and l@ means for causing said synchroscope to assume a denite position or condition when the subjects of study, such as the internal combustion engines above suggested, are operating in synchronism, and to display a different type of in- 15 dication when said engines are rotating at different speeds. y

This and other objects and advantages will appear more fully from a consideration of the detailed description which follows, with refer- 20 ence to the accompanying drawing, wherein is i1- lustrated one embodiment of the invention. It is to be expressly understood, however, that the drawing is for the purpose of illustration only, and is not designed as a denition of the limits 25 of the invention, reference being had for this purpose to the appended claims.

` In the drawing:

Fig. 1 is a schematic representation of the invention as applied to two internal combustion 3@ engines; and

Figs. 2, 3 and 4 show other embodiments thereof.

Referring rst to Fig. 1, reference characters D1 and T1 designate rotatable parts of the ig- 35 nition system of engine No. i and D2 and T2 designate the corresponding rotatable parts (distributor arm and timer, respectively) of engine No. 2, the primary and secondary windings of the induction coils being indicated at P1 and 4@ S1, P2 and S2.

Branching from the primary ignition circuits, wires 5, 6 lead to the primary windings l, 8 respectively, of transformers having secondary windings 9, i0 connected by leads ii, i2 the lat- 5 ter having a voltmeter or equivalent instrument inserted therein to reflect the time difference, if any, between the peak values of the E. M. F. of circuits 5 and t, which in turn coincide with the periods of interruption of current flow at the 5@ points B1 and B2 of the respective ignition timers.

It is intended that the windings 'l and d will have sufficiently high resistance to prevent shunting of any material amount of energy from the ignition circuit; that is, even though they provide a theoretical momentary path to ground (i3, i4) at the moment of current interruption at B1 and Bz, these windings l and 8 are a practical barrier to loss of the primary circuit current during such moment, while nevertheless effective to indicate (through induction into the 5 secondary circuit il, i2) the timing of the interrupting of current flow in the two ignition circuits.

It follows that indicator i5 will remain steady, indicating synchronism in the speeds of engines it i and 2, when the-interrupting impulses, or beats in circuits' 5 and t coincide to thereby produce induced currents" of equal potentials in transformer windings 9 and lil.

Fig. 2 shows a second embodiment or the ini5 vention, using a single transformer in place of the two indicated at l and B in Fig. l. This single transformer has its primary winding it connected so as to receive the opposing pulsa- Ytions of each of the two ignition circuits, and ge when these opposing pulsations are so synchronized as to have the eiect of nullifying one another, the result will be an absence of any potential gradient in the circuit through the secondary winding 22 and the indicator (voltmeter 25 or its equivalent) 23. A 'condenser 2d may be provided to by-pass those components of the current which are not necessary to a determination of the actual value ci the E. M. F. impulses in the meter circuit, and the fundamental 3o frequency thereof.

In Fig. 3 a lter unit is Asubstituted for 'the transformer 2l, 22 of Fig. 2, and an aural indicator 21 (head-phones, for example) for the visual indicator 23 of Fig. 2. 'I'he lter unit may 35 include suitably proportioned inductances and capacitors connected as shown at t@ and t; the windings 3i of Figs. 2 and 3 corresponding to the windings P1 and P2 of Fig. l.

In Fig. 4 the circuit interrupters te, 3d (cor- 4@ responding to the circuit interrupters T1 and 'Ii` of Fig. land to the circuit interrupters t@ of Figs. 2 and 3) are placed directly in series with the primary windings i3 of -the transformers whose secondary windings it are connected g5 through indicator dii in the same manner as are windings d and it of Fig. l; d@ being a source of direct current corresponding to il of Fig. l. With this arrangement of Fig. d the interrupters 33, Se may be units separate and distinct 5@ from the ignition elements of Figs. i-S, but nevertheiess rotatable in synchronism with the associated engines (not shown, but corresponding to engines i and 2 or Fig. l).

What is claimed is:

i.. Means Jior indicating the speed relationsnipv between two engines, each equipped 'with an engine driven periodic circuit interrupter, said means comprising apair of circuits including said interrupters, and a secondary circuit containing a single index element responsive 'to the difference, if any, in the frequencies nf current interruption in said first-named circuits.

2. Means for indicating the speed relationship between two engines, each equipped with an engine driven periodic circuit interrupter, said means comprising a pair of circuits including said interrupters, and a secondary circuit containing a, singley index element responsive to the difference, if any, in the frequencies of current interruption in said first-named circuits and means in said secondary circuit for coupling said irst-named circuits to produce energization of said index element.

3. In a signaling system for indicating synnieuwe chronous operation of two interna combustion engines, each having an ignition system including an ignition induction coil and primary circuit interrupter, the combination of an electrical signal device and a circuit connecting the signal device and both of the primary windings of 'the induction coils in series independently of said interrupters.

i. In a signaling system for indicating the speed of operation of an internal combustion engine having an ignition system including an ignition induction coil and primary circuit interrupter therefor, the combination of an electrical signaling device and a circuit connecting the signaling device and the primary winding of the induction coil in series independently of said interrupter.

JOHN C. FRANKLIN. DON C. MCRAE.

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