US2569267A

US2569267A - Engine starter gearing

Info

Publication number: US2569267A
Application number: US167103A
Authority: US
Inventors: Arthur R Tobias
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1950-06-09
Filing date: 1950-06-09
Publication date: 1951-09-25
Anticipated expiration: 1968-09-25

Description

A. R. ToBlAs 2,569,267

ENGNE STARTER GEARING Sept. 25, 1951 Filed June 9, 1950 f' @j 6 mm3 2:13a

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ATTORNE Y WITNESS:

Patented Sept. 225,y 1951 ENGINE STARTER GEARING Arthur n. Tobias, Elmira, N. Y., assigner to Beh# dix Aviation Corporation, Elmira Heights, N. Y., a corporation of Delaware Application June 9, 1950, Serial No. 167,103

The present invention relates to engine starter gearing, and more particularly to'that type of drive in which the engagement of a drive pinion with an engine gear is secured by threaded traversing means.

In drives of this type where the pinion is traversed longitudinally into mesh with the engine gear by acceleration of lascrew shaft, it is customary to provide some means for relieving abutting or jamming conditions which sometimes occur when the teeth of the pinion collide with the teeth of the engine gear. Such means is usually in the form of a longitudinally yielding connection between the starting motor and pinion which permits the pinion to pause in its traversal and provide time for the torque from the screw shaft to build up and index the pinion into proper registry with the tooth spaces of the engine gear. In the patent to4 McGrath, 1,822,163, the same problem is solved by providing means extraneous to the threaded connection for indexing the pinion when its longitudinal movement is interrupted by tooth abutment with the engine gear.

It is an object of the present invention to provide a starter drive having novel means for indexing the pinion in case its meshing movement is arrested.

It is another object to provide such a device in which the indexing means is positive in its action and permits no yfree lost motion of the pinion.

It is another object to provide such a device in which the indexing means is incorporated in the body of the drive without requiring any added or extraneous elements.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing in which:

Fig. 1 is a side elevation partly broken away and in section `of a preferred embodiment of the invention showing the parts in idle position.

Fig. 2 is a similar view showing the parts in cranking position.

Fig. 3 is a similar view showing the .parts in the positions assumed in case of tooth abutment between the drive pinion and engine gear; and

Fig. 4 is a side elevation of the drive rotated by 90 from the position illustrated in Fig. 3.

In Fig. 1 of the drawing there is illustrated a power shaft I on which a driving clutch member 2 is xedly mounted as by means'of a cross pin 3 retained is position by a, ring 4. Clutch member 2 has overrunning clutch teeth 5 adapted to engage corresponding teeth 6 on a screw 55 1 Claim. (Cl. 74-7) shaft I which is slidably journalled on thev power shaft. l -Y A pinion 8 is journalled on the power shaft I for longitudinal movement into and out of mesh with an engine gear 9. A cup II is rigidly mounted at one end on the pinion as indicated at I2, and at its other end is provided with aradial flange I3 which is anchored as indicated at I4 in the open end of a barrel member I5 enclosing the drive. The barrel I5 is provided with a pair of inclined or spirally arranged slots I 6 (Fig. 4), and a control nut Il is threaded on the screw shaft I and provided with a radial flange I8 having diametrically arranged lugs I9 extending into and having a loose sliding t in the spiral slots IB. Means for normally maintaining the `control nut with its lugs I9 at the left hand ends of the slots I6 and yfor yieldably resisting longitudinal movement of the control nut to the right in the barrel I5 is provided in the form of a cylinder 2I of elastically deformable material such as rubber, seated at one end on the control nut against the Iiange I8 and at its other end vbearing against the radial flange 22 of a ferrule 23 which is clamped against the flange I3 of sleeve II by crimping over the end of the barrel I5 as shown at I4.

The barrel I5 is provided with a reduced extension 24 terminating in an inwardly directed flange 25. An anti-drift spring 2B bears at one end against the ange 25 of the barrel, and at its other end against a flange 2l of ring Ii on which it is seated.

In operation, starting with the parts in the positions illustrated in Fig. 1, rotation of the power shaft I in the direction -of the arrow (a) causes the screw shaft I to be rotated by reasonof its clutch connection 5, 6 with the drive clutch member 2. Control nut Il is thereby traversed to the right. moving the barrel I5, cup II and pinion 8 through the rubber cylinder 2| until the pinion is meshed with the engine gear 9 whereupon the flange 25 of the barrel engages the driving clutch member 2 as shown in Fig. 2. Further longitudinal movement of the control nut causes compression of the rubber cylinder, whereby the control nut I'I is yieldably constrained to rotate with the screw shaft 1, which rotation is transmitted by lugs I9 to the barrel I5 and pinion 3.

If, during the meshing mov-ement, a tooth of the pinion abuts against a tooth of the engine gear, the movement of the pinion is arrested while the control nut II continues to move forward compressing elastic member 2| as shown in Fig. 3. Inasmuch as the slots I6 in the barrel 3 are inclined or skewed as shown in Fig. 4, the consequent longitudinal movement of the lugs I9 of the control nut in the slots I6 causes the barrel, and consequently the pinion 8, to be indexed by the camming action of the lugs in the slots so as to bring the teeth of the pinion into proper registry with the tooth spaces of the engine gear. As soon as this happens, the expansion of the elastic member 2| snaps the ypinion into initial mesh, and meshing and cranking proceed as usual.

When the engine starts, the acceleration of th pinion, barrel, and control nut with' 'respect to rotary inertia is dissipated.

shaft, a pinion slidably journaled on the power shaft for movement into and out of mesh with an engine gear, a. barrel member surrounding the screw shaft, xed at one end to the pinion and slidably journaled at its other end on the power shaft, a control nut on the screw shaft having an inclined driving connection to the barrel, and yielding means in the barrel opposing longitudinal movement of the nut on the barrel; in which the barrel is provided with diametrically arranged spiral slots, and the control nut is formed with .radially extending lugs loosely tting in the spiralslots, and the yielding means is arranged between thelcontrol nut and pinion so as 'oo opvposelongitudinal movement of the control nut in the barrel toward the pinion.

Although but one form of the invention vhas been shown and described in detail, it will be understood that changes. may he made in the design and arrangement of the parts without departing from thespiritof the.:,'uiyer 1ti0n.,-v

Iclam: Y, c i t ,Y z In anv engine, starter driveA 21.12QYSershaftL ka screw shaft .meenten thereQn, means for QQrlf nesting the scremshait torqtate with the pow?? ARTHUR R. TOBIAS.

REFERENCES CITED The following references are of record in the le. of thisv patent:

UNITED STATES PATENTS