US2563999A - Engine starter - Google Patents

Description

Patented Aug. 14, 195i UNITED STATES PATENT OFFICE ENGINE STARTER Raymond H. Foster, Hasbrouck Heights, and

Clinton H. Havill, South Orange, N. .L, assignors to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application May 15, 1946, Serial No. 669,91!

'=7 Claims. 1

This invention relates to engine starters, and particularly to improvements in a starter clutch jaw member and elements associated therewith.

A starter of one type to which the invention applies, comprises an axially stationary nut rotatably driven through the intermediary of a dry or wet disc clutch, and a screw shaft in the nut splined to a starter clutch jaw member for cooperation with a clutch element on an engine shaft.

The starter clutch member is frictionally held so that, when the nut rotates, it first moves the screw shaft longitudinally from an initial position, which likewise moves the clutch member, through the intermediary of a spring and a meshing rod, into engagement with the engine clutch element, whereupon the latter is rotated to normally start the engine.

The end of the starter casing, at which its clutch member is disposed, is disposed within one end of the engine crank case, which presents the problem of sealing the starter casing against the ingress of the engine oil to the aforesaid disc clutch and other parts.

- Also, the starter is subjected to the vibration of the engine which, unless counteracted, as by the present invention, has adverse affects on parts of the starter, such as the oil sealing means.

In starters of the above-indicated type heretofore employed, the meshing rod is subject to break-age, because it is too small in diameter, and causes oil leakage, between the starter clutch member or jaw and the meshing rod, through a sliding seal. Such leakage is very undesirable, since any oil reaching the disc clutch causes the clutch torque setting to be reduced, so that the starter cannot start the engine.

It is undesirable to have screw threads or other sharp edges on certain parts of thedriving jaw itself, which must be free from such weakening influence, so that a mounting for the jaw on the rod, or a seal to prevent the aforesaid leakage, should be provided without such threads or edges.

The jaw should be prevented from displacement by reason of its position or other causes such as vibration, and any means for holding the jaw against such displacement should be directly accessible from the exterior of the starter, so that the jaw may be readily assembled and replaced.

Among the objects of the invention are to overcome the above-mentioned undesirable features and to provide the advantages mentioned, and to do so in an effective manner by novel'and improved means.

Another object is to provide a fixed or permanent seal, between a driving clutch member and a meshing rod, which may be efieoted without screw threads or similar weakening sharp edges on the clutch member.

Another object is to provide the above-mentioned seal in combination with jaw retaining means which is directly accessible from the exterior of the starter or like structure for the removal of the jaw.

Another object is to provide novel means whereby, as in a starter for mounting on an engine having high amplitude of vibration, the meshing rod and other parts are prevented from adversely affecting the oil or fluid seal and, as where the engine is of low amplitude of vibration, the meshing rod may be of. large diameter and hollow to enclose the Spring means through which the screw shaft advances the starter jaw.

Another object is to provide means whereby the starter clutch jaw has automatic radial centering movement relative to the engine clutch jaw element.

Another object is to provide means whereby a nut or the like, for holding the starter clutch jaw on the meshing rod, may be turned home and removed without the aid of a separate tool' for holding the jaw.

A further object is to provide improved means of the above-indicated character that are simple and durable in construction, economical to manufacture and effective in operation.

These and other objects and features of the invention are pointed out in th following description in terms of the embodiment thereof which is shown in the accompanying drawing. It is to be understood, however, that the drawing is for the purpose of illustration only, and is not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

In the drawing:

Figure 1 is a, side view, partially in section and partially in elevation, of a portion of a starter structure embodying the invention in one form;

Figure 2 is a detail sectional View, taken substantially along the line 2-2 of Figure 1.

Figure 3 is view similar to a portion of Figure 1, showing the invention in modified form,

Figure 4 is an enlarged detail'of parts shown in Figure 3, in position prior to being placed in the position thereof in Figure 3; and

Figure 5 is a view taken substantially along the line 5-5 of Figure 3.

In Figure 1, which shows only a portion of a starter sufficient for an understanding of the invention, the structure comprises, in general, an inner starter casing portion I8 secured, at one end, to an engine crank case l2, as by studs l4, and, at the other end, to another starter casing portion l6, as by screws l8. A casing member 28, secured, as by the studs l4 between the casing portion I8 and the crank case [2, and to the portion l8, as by screws H, has a shoulder 22, which retains a flange 24 of a rotatable barrel 26 relative to the casing portion [8.

An end wall 28, of the barrel 26, supports planet gears 38 operating between an orbital gear 32, fixed to the casing portion 18, and a sun gear 34, on a shaft 36, which sun gear is driven in a usual manner by a motor through further speed reducing means. A spline nut 38 is connected to the barrel 26 therein by a torque-limiting disc pack 48 having interlayered discs fixed to the nut and the barrel, respectively, and axially biased together by springs 42 held in adjusted relation to the discs, as by a ring nut 44 screw threaded in the opposite end of the barrel 26. A ring member 35, carrying centering projections 61 for the springs 42, acts, in the retracted position of the member 52 illustrated, as a bearing for the latter, but has a chamfer 4| which cooperates with a chamfer 39 on the member 52, in the extended position of the latter, to permit a certain amount of radial movement of the member 52 for automatic centering relative to the engine jaw element 54.

A screw shaft 46, having long-lead thread connection to the spline nut 38 therein, surrounds a hollow bearing sleeve 48 for the shaft 36, and has an axially slidable spline connection 58 to a starter clutch jaw member 52, which is adapted to engage a cooperating engine clutch jaw element 54 on an engine shaft 56. The starter clutch jaw member 52 is adapted to rotate, and move axially toward the engine element 54, in an oil seal and friction device 55 mounted on the member 28. The long lead thread connection between the screw shaft 46 and the spline nut 38 and the spline connection 58 are loosely fitted to permit limited radial play between the screw shaft 46 and spline nut 38 and between the screw shaft 46 and the member 52. The radial play between the respective parts permits the radial movement of the member 52 as previously described.

The member 52 has an axially apertured hub or Web portion 58 through which extends a reduced diameter shank portion 68 of a meshing rod member 62, which further comprises a portion 64 of larger diameter having a radially outwardly projecting flange 66 axially behind an inwardly projecting flange 68 on the screw shaft 46.

A groove 18, in the portion 64 facing the hub 58 of the starter jaw 52, is adapted to receive a doughnut gasket or seal 12 for compression in the groove, through the intermediary of the hub, by holding means, such as a nut (4 locked in position on the shank 68. The nut 14 and the flange 66 cooperate to normally hold the clutch member 52 against complete separation from the starter.

The meshing rod 62, in this instance, is constructed to be relatively short in length whereby to reduce its mass and the inertia of the assembly including the rod and the jaw member 52 as to radial vibration, the assembly thereby being a better radially balanced unit against angular deflection relative to its axis. 7

A substantial clearance 13 is provided between the flange 66 of the meshing rod and the screw shaft 46, and a similar clearance 15 is provided 4 between the portion 64 of the meshing rod and the screw shaft, whereby the jaw member 52 may automatically adjust itself radially when engaged to the engine jaw element 54, and whereby the transmission of vibration from the screw shaft 46 to the clutch jaw through the meshing rod 62 is prevented or reduced.

The screw shaft 46 is limited in its right hand axial movement, as viewed in the drawing, by engagement with an end flange 16 on the bearing sleeve 48, and, in its left hand axial movement, by engagement of a shoulder 18 on the shaft with a shoulder 88 on the spline nut 38.

As better seen in Figure 2, the mesh rod portion 64 is provided with flats 11 cooperating with corresponding flats in the screw shaft whereby, when the screw shaft engages the flange 16 of the sleeve 48, and when the shoulder 18 on the screw shaft engages the shoulder 88 in the spline nut 38, the nut 14 may be screwed home or released from the shank 68, as the case may be, without requiring a separate tool for holding the clutch member 52.

A spring 82, around the bearing sleeve 48 and behind the mesh rod 62, acts between the mesh rod flange 66 and a spring backing ring 83 of angle section secured in position by split lock ring structure 84 held in a groove in the screw shaft 46 to hold the mesh rod and the clutch member 52 relative to the screw shaft in the given or initial positions shown, and to allow the starter jaw member 52 to yield axially against the action of the spring 82 when the member 52 engages the engine jaw element 54.

In the latter connection, it is of particular note that the mesh rod 62 does not slide axially in the jaw hub 58, as mesh rods generally do in former standard practice, but is normally a fixed part of the member 52' having a seal effected by the gasket 12, which is also normally fixed or permanent at all times. It is of further note that this result is obtained, without resort to screw threads or other sharp edges tending to start fracture of the jaw member, and without additional structure, or features, which deter free direct access from the exterior of the starter to the holding means or nut 14 for the ready assembly and replacement of the jaw 52.

In operation, when the shaft 36 is turned by the motor through the intermediary of the abovementioned gear or speed reducing means, the sun gear 34 turns the planet gears 38, which, since they are carried by the barrel 26 and are in mesh with the fixed orbital gear 32, react by turning the barrel 26 and, with the latter, the spline nut 38 through the intermediary of the disc clutch 48.

With the operating member or screw shaft 46 for the jaw member 52 splined by the connection 58 to the jaw member 52, and the latter engaged by the combined oil seal and friction device 55, the above-mentioned turning of the barrel 26 causes the screw shaft 46 to advance to the left to first engage the member 52 to the engine element 54. Continued rotation of the jaw member 52, when the shoulder 18 engages the shoulder 88, drives the element 54 and the engine shaft 56 to normally start the engine.

When the engine starts, the engine element 54 overrides the starter jaw member 52, and when the starter motor is deenergized, the member 52 is cammed back to the position shown, in a usual manner. If the engine shaft 56, for any reason, abnormally resists turning, or if the engine backfires, the reaction is absorbed in the starter by the disc clutch pack 40.

Referring to Figure 3, the construction and operation are similar to those above described, with substantially the only variations of structure germane to the invention residing in the rearrangement and form of a mesh rod 90, a screw shaft or operating member 92, a spring 99 and associated parts. In this instance, the mesh rod 90 is hollow and longer than the mesh rod 62, and encloses the spring 94, and has a flange 96 cooperating with the nut 14 to normally prevent complete separation of the jaw member I04 from the operating member 92 and the starter.

A sealing gasket I corresponding to the gasket I2, instead of being in a groove in the mesh rod, is in a groove I02 of a starter jaw I04, but may, of course, be in a groove in the meshing rod or otherwise constituted to like effect.

The spring 94 acts similarly to the spring 02 between an internal shoulder 95 of the mesh rod 90 and means [06 carried by the screw shaft 92. The means I06 comprises a spring backing member 91 corresponding to the ring 83 of Figure 1, and a split lock ring structure 99 corresponding to the ring 84 of Figure 1, and similarly held in a groove in the screw shaft 92.

As better shown in Figure 4, to avoid a sharp edge in the jaw I04 itself, the groove I02 is provided with a well rounded fillet I08. The gasket I00 shown, is of circular perimetral cross section of an area such that, when the nut 14 is turned home from its position of Figure 4 to its position of Figure 3, the gasket is squashed over a broad area by the clutch member I04 into broad area sealing engagement with a radial surface of the mesh rod 90, at the right of the gasket as viewed in the drawing, and with an annular surface of the rod under the gasket.

Although only two embodiments of the invention have been illustrated and described, various changes in the form and relative arrangements of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is, therefore, to be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. In an engine starter, the combination of a starter clutch member adapted to engage an engine clutch portion, a screw shaft element, a meshing rod element, said elements telescopically fitting each other and having axially opposite lateral shoulders, a fluid seal between said member and the meshing rod, means fixing said member to said meshing rod and compressing said seal, and means including spring means operating between the screw shaft and the meshing rod through said shoulders for advancing the member into engagement with said portion.

2. In an engine starter, the combination of a starter clutch member adapted to engage an engine clutch element, a spline nut, a screw shaft cooperating with said nut, a hollow meshing rod on which said member is mounted, and spring means in said rod responsive to axial movements of said shaft to move said rod to engage said member to said element.

3. In an engine starter, the combination of a starter clutch member adapted to engage an engine clutch element, a spline nut, a screw shaft cooperating with said nut, a meshing rod on which said member is mounted, and spring means behind said rod responsive to movement of said 6 shaft to move said rod to engage said member to said element.

4. In an engine starter, the combination of a starter clutch member adapted to engage an engine clutch element, an axially stationary rotative driving nut, a screw shaft, a meshing rod, a nut or the like for removably securing said member on said meshing rod, and means including means for locking the screw shaft at opposite axial limits of its travel relative to the driving nut and preventing turning of the meshing rod relative to the screw shaft and adapted to hold the meshing rod stationary for screwing said securing nut home at one of said limits and releasing it at the other of said limits.

5. The combination of a casing, means including an axially stationary rotatable nut and a hollow screw shaft cooperating with said nut in said casing for axial movement relative to said nut and rotative movement therewith and having an inner flange, a clutch jaw member for cooperation with a clutch jaw element exteriorly of said casing, said clutch member being connected for operation by said shaft for axial and rotative movements with said shaft and axial movement relative thereto; and means for frictionally holding said clutch member to cause said axial movement thereof relative to said nut, spring means responsive to the axial movement of said shaft to move said clutch member axially therewith into operative relation to the exterior clutch element, which spring means yields for said axial relative movement and overriding of said clutch member by said clutch element, said clutch jaw member normally being permanently sealed against the passage of fluid therethrough at all times including periods of said axial and rotative movements, and means in said hollow screw shaft having a flange behind said inner flange holding said clutch member against separation from said screw shaft and including means directly accessible from the exterior of said casing providing for said separation.

6. In an engine starter, the combination of a casing adapted for mounting on the engine with one end of said casing in the engine crank case, a starter clutch member mounted in an opening in said end exposed to oil in said crank case, a nut, means for frictionally holding and sealing said member relative to said casing, and means in said casing including a meshing rod on which said nut is mounted for removably holding said member on said rod, an oil seal normally fixed in position by said nut between said member and said rod, spring means, means including a screw shaft for moving said member axially through the intermediary of said spring means into engagement with said engine clutch element and rotating said member to start the engine, and means including said meshing rod and said screw shaft providing radial play between the rod and the shaft for rendering said member radially self centering relative to said element and prea lateral shoulder behind said screw shaft shoulder, spring backing means removably locked to the screw shaft therein, spring means between the mesh rod element and said spring backing .means through the intermediary of which the screw shaft moves the starter jaw axially into engagement with an engine jaw, and means cooperating between said shank and said wall locking the starter jaw to the mesh rod element. RAYMOND H. FOSTER. CLINTON H. HAVILL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 909,187 Illmer et a1. Jan. 12, 1909 1,717,847 Litle June 18, 1929 1,990,015 Allen Feb. 5, 1935 10 2,316,121 Nardone Apr. 6, 1943 2,374,990 Gilbert May 1, 1945

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