US2643304A - Ignition timer - Google Patents

Description

June 23, 1953 A. G. LAUTzx-:NHISER 2,643,304

IGNITION TIMER Filed Nov. 5, 1949 Y Patented June 23, 1953 IGNITION TIMER Argyle G. Lautzenhiser, Anderson, Ind., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November 3, 1949, Serial No. 125,353

(Cl. 20G- 31) 11 Claims.

This invention relates to ignition timers having means responsive to engine suction for advancing ignition timing as engine suction increases. This means comprises a suction chamber connected with the engine intake and closed by a flexible, fabric diaphragm connected with a plate supported for rotation about the axis of the timer cam which controls a circuit breaker supported by the plate. As engine suction increases, the diaphragm moves toward a wall of the suction chamber to advance the ignition timing against the action of a spring which operates to retard ignition when suction decreases.

An object of this invention is to provide for the support of the rotatable circuit breaker plate in a simple and economical manner whereby the cost is reduced. This is accomplished by addition of only three parts to those which are necessarily required. The three parts are a bearing shoe movable with the circuit breaker plate and journalled on arcuate flanges with which the fixed support for the plate is provided, a spring for urging the shoe against the anges oi the xed plate and for maintaining assembly of the shoe with the plate and a rivet for attaching the spring to the plate.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embcdi ment of the present invention is clearly shown.

In the drawings: Y

Fig. 1 shows a plan view of an ignition timer embodying the invention.

Fig. 2 is a fragmentary sectional view on line 2--2 of Fig. 1.

Fig. 3 is a view of a blank for the fixed plate f the timer.

Fig. 4 is a fragmentary sectional view on line 4 4 of Fig. l.

The timer may be one of the type disclosed in the copending application Ser. No. 310 led January 2, 1948 of John T. Fitzsimmons now Patent No. 2,487,231. This timer has a housing I0 supporting an engine driven shaft II having an eX- tension I2 on which a timer cam I3 is journalled. Cam I3 is connected with the shaft I I by a speed responsive device I4 which varies the angular relation of cam I3 and shaft II as speed changes. Cam I3 supports and drives a distributor rotor for distributing sparking impulses to terminals of a distributor cap connected with an ignition coil and with spark plugs. A fragment of the rotor is shown at I5 and a fragment of the cap at I6 in Fig. 2.

A xed plate 20 supported within the housing I0 provides arcuate ilanges 2I on which a rotatable plate 23 is journalled by means to be described. Plate 23 carries a circuit breaker comprising (Fig. 1) a lever 24 pivoted on a stud 25 and insulated therefrom and carrying a contact 26 engageable with a contact 2 attached to a bracket 28 supported on plate 23 and pivoted on the stud 25 which is attached to plate 23. A leaf spring 23 attached topa iixed plate 30 and to lever 24 urges the lever counterclockwise so that a rubbing block 3I will be engaged by the cam I3 to separate contact 2B from contact 21 against the action of spring 29.

For adjustment of contact separation, bracket 28 can be adjusted about stud 25 by the turning of a slotted disc 33 received by a slot 34 in bracket 28 and. having an eccentric shank 35 journalled in the plate 23. The bracket 28 is held in ad'- justed position by the tightening of a screw 36 passing through an arcuate slot 31 in bracket 28 and threaded into plate 23.

Plate 3D which is supported by bracket 28 is connected by screw 38 and nut 39 with a wire 40 f connected with a terminal 4I and with a wire 42a connected with one foil of a condenser in a metal case 42 electrically connected with the other condenser ioil and attached to a clip 43 which a screw 44 fastens to plate 23 which is grounded by a connection comprising screw 45, clip 46 and ileXble wire 4'! soldered at 48 to housing I3.

Screw provides a pivotal connection between plate 23 and a link 5E connected with a diaphragm 5I whose periphery is clamped between flanges of shells 52 and 53 the latter providing the xed wall of a suction chamber closed by' the diaphragm and connected with the engine intake. Movement of the diaphragm with increase of engine suction is opposed by a spring 54 coniined under initial compression between the diaphragm 5I and a bushing 55 screwed into a tube 55 attached to shell 53 and adapted 'to receive a coupling for connecting a pipe connected with the engine intake.

The lianges 2| have cylindrical outer surfaces of the same radius and are concentric with the aXis of cam I3. The plate 23 carries an arcuate shoe 50 preferably of smooth, molded plastic having an inner cylindrical surface of the same curvature as the outer cylindrical surfaces of the iianges 2I of plate 23. A leaf spring 6|, which is attached to plate 2i) (Fig. 2) by a rivet 62 and which extends through a straight slot 63 in plate 20 and through an arcuate slot 64 in plate 23, presses the shoe againstV the ilanges 2| of plate 20, presses the shoe 50 against the plate 23 so that lugs 65 (Figs. 1 and 4) of the shoe are retained in holes in the plate 23 so that the plate 23 is in fact journalled on the flanges 2| for rotation about the axis of cam I3. Furthermore, the spring 6| urges the plate 23 toward the plate so that three studs 66 attached to plate 23 bear, tripod-like upon plate 2|). The spring 6| causes the studs 66 to engage plate 20 and the shoe 60 to engage flanges 2| with light pressure so that frictional resistance to movement of plate 23 by the suction device Will be Very small.

It will be noted that the iianges are located on that side of the cam |3 opposite to the lobe which engages the rubbing block 3|. Therefore the force which the cam delivers to the rubbing block is in a direction to cause the shoe 60 to engage the flanges 2| with greater pressure and not less. The shoe 60 does not bounce on these flanges when the rubbing block is intermittently engaged by the cam.

Plate 20 is shaped from a sheet metal stamping or blank 20S having tangs 20a which afterwards bent on lines 20h at right angles tothe stamping as shown in Fig. 2. The central opening of the stamping is shaped to provide tangs 2h21l which are afterwards bent on lines 2lb to provide the flanges 2|. The hole E3 for the spring 6| (indicated in dot-dash lines in Fig. 3) and the hole 62a are formed when punching the blank 20S.

Only three additional parts are required for the journalling of plate 23 on plate 26, namely, the shoe 6U, the spring 6| and the rivet S2.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An ignition timer comprising a housing, an engine driven shaft journalled in the housing, a cam connected with the shaft, a plate having a central opening fixed in the housing in a plane at rig-ht angles to the cam axis, a circuit breaker includingV a rubbing block engaged by lobes of the cam to move it to open the circuit breaker, an arcuate bearing provided by the plate on one side thereof and at the marginal wall of the central opening and on the side of the cam opposite to the side on which the rubbing block is located, said bearing being coaxial with the cam axis, a second plate supported by the first plate having one opening to receive the bearing and supporting the circuit breaker, a shoe supported by the second plate and presenting a cylindrical surface engaging the arcuate bearing, a spring attached to the first plate and engaging the shce and applying pressure thereto in a direction such that the shoe is urged against the arcuate bearing and the second plate toward the first plate, and means for rotating the second plate to change the ignition timing.

2. A timer according to claim 1 in which the arcuate bearing is provided by two flanges integral with the first plate formed by shaping tangs provided by the sheet metal blank from which the first plate is formed.

3. A timer according to claim 1 in which the shoe is made of molded plastic` with two lugs which extend therefrom into recesses provided by the second plate, said shoe presenting an inclined surface to the spring for engagement thereby whereby the springv urges the shoe against the arcuate bearing, against the second plate to effect retention of the shoe lugs in the second plate recesses and the spring urges the second plate toward the first plate.

4. An ignition timer comprising a housing, an engine driven shaft journalled in the housing, a cam connected with the shaft, a plate having a central opening attached to the housing; a circuit breaker including a rubbing Yblock engaged by lobes of the cam to move it to open the circuit breaker, an arcuate bearing iiange carried by the plate adjacent the marginal wall of the central opening, said iiange being on one side of the plate and on the side of the cam opposite the side on which the rubbing block is located; a second plate supported by the first plate and having a central opening to receive the arcuate bearing flange and supporting the circuit breaker; an arcuate shoe supported by the second plate and engaging the bearing iiange of the rst plate, a leaf spring attached to the first plate and extending through an arcuate slot provided by the second plate and having its free end engaging the shoe and applying lpressure thereto to urge the shoe against the arcuate bearing flange and the second plate toward the first plate, and means for rotating the second plate to change the ignition timing.

5. An assembly comprising a plate having a central opening adapted to be xed within the housing; a circuit breaker plate having a central opening, said circuit breaker plate being arranged in parallel relation to the fixed plate; an arcuate bearing associated with the fixed plate extending in an axial direction through the opening of the circuit breaker plate and projecting beyond said circuit breaker plate; an arcuate bearing member associated with the circuit breaker plate yadapted to engage the bearing on the fixed plate, said bearing members having bearing surfaces, the radii of curvature' of which are the same, whereby the circuit breaker plate may be rotated back and forth with respect to the fixed plate; a leaf spring having one end connected to the fixed plate and having its free end projecting through an arcuate slot provided by the circuit breaker plate and bearing against its associated bearing'member, said spring applying pressure in a manner so that the bearing surfaces are held in contact with each other and the circuit breaker plate is urged toward the fixed plate.

6. In combination with an ignition timer, including a housing; a plate having a central opening adapted to be fixed in the housing and including an arcuate bearing surface adjacent the rcenter aperture and. in a plane out of parallel with the plane of the fixed plate; aV rotatable plate having a central opening and including a bearing surface adapted t0 engage the arcuate bearing surface of the fixed plate; and yieldable means carried by the fixed plate and passing through the rotatable plate for causing the bearing Vsurface of the movable plate to engage the bearing surface of the fixed plate.

7. In combination with an ignition timer, including a housing; a plate having a central opening adapted to be fixed in the housing and including an arcuate bearing surface adjacent the central aperture, said bearing surface being less than in extent and in a plane out of parallel with the plane of the fixed plate; a rotatable plate having a central opening and including a bearing surface adapted to engage the arcuate bearing surface of the xed plate; and yieldable means carried by the fixed plate and passing through the rotatable plate for causing the bearing surface of the movable plate to engage the bearing surface of the fixed plate.

8. In combination with an ignition timer, including a housing; a plate having an opening adapted to be fixed in the housing and including an outer cylindrical bearing surface adjacent the opening, said bearing surface being less than 180 in extent and in a plane out of parallel with the plane of the fixed plate; a rotatable plate having an opening in axial alignment with the opening of the Xed plate; non-metallic antifriction bearing means associated with the rotatable plate, said bearing means having inner cylindrical surfaces adapted to engage the outer cylindrical bearing surfaces on the fixed plate; and resilient means acting on the anti-friction bearing means for causing same to engage the bearing surfaces of the xed plate.

9. In combination with an ignition timer, including a housing; a plate having a central opening adapted to be ixed in the housing, said plate having integral flanges adjacent the opening and presenting outer cylindrical bearing surfaces, said cylindrical surfaces being less than 180 in extent; a movable plate having an opening in axial alignment with the opening of the xed plate; anti-friction means associated with the movable plate and providing inner cylindrical surfaces adapted to engage the outer cylindrical surfaces of the flanges, whereby the movable plate is journaled on the flanges; and resilient means carried by the xed plate and passing through the movable plate for causing the bearing surfaces of the anti-friction means to engage the bearing surfaces of the flanges and also for urging the movable plate toward the xed plate.

10. In combination with an ignition timer, including a housing; a driven shaft journaled in the housing, a cam connected with the shaft; a plate having a central opening xed Within the housing; a circuit breaker including a. rubbing block engaged by lobes of the cam to actuate the circuit breaker; an arcuate bearing surface provided by the xed plate adjacent the central opening and on the side of the cam opposite to the side on which the rubbing block is located; a rotatable plate having a central opening; an anti-friction bearing member associated With the movable plate and adapted to engage the arcuate bearing provided by the xed plate; and resilient means carried by the fixed plate and passing through the rotatable plate for causing the antifriction bearing member to engage the arcuate bearing surface on the xed plate.

11. In combination With an ignition timer, including a housing; a plate having a central opening adapted to be i-lxed to the housing and including an arcuate bearing surface adjacent the central opening; a rotatable plate including a bearing having a bearing surface adapted to engage the arcuate bearing surface of said fixed plate; and yieldable means having one end attached to said xed plate and having its free end engaging the bearing of the rotatable plate and applying pressure thereto in a direction so that the bearing surface of the bearing of the rotatable plate will engage the bearing surface of the xed plate.

ARGYLE G. LAUTZENHISER.

References Cited in the file 0f this patent UNITED STATES PATENTS Number Name Date 2,075,904 Lang et al. Apr. 6, 1937 2,348,236 Arthurl May 9, 1944 2.390.050 Bales Dec. 4. 1945

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