US2683990A

US2683990A - Engine starter

Info

Publication number: US2683990A
Application number: US254542A
Authority: US
Inventors: Gilbert Samuel
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1951-11-02
Filing date: 1951-11-02
Publication date: 1954-07-20
Anticipated expiration: 1971-07-20

Description

July 20, 1954 5 g B 2,683,990

ENGINE STARTER Filed NOV. 2, 1951 8 INVENTOR.

I g] SAMUEL G/LBERT Patented July 20, 1954 ENGINE STARTER Samuel Gilbert, Cedar Bendix Aviation Corporation, Teterboro, N. J.,

Grove, N. J., assignor to a corporation of Delaware Application November 2, 1951, Serial No. 254,542

2 Claims. 1

The present invention relates to engine starters and particularly to engine starter meshing mechanism.

In engine starters usually some means are required for engaging the starter jaw with the engine to be started. One method used is to frictionally hold the starter jaws to cause axial movement thereof. This method has numerous disadvantages in that the friction means are present during the operation of the starter. Also for starts at low temperatures, the friction means are not adequate for holding the starter jaw to cause the necessary axial movement for jaw engagement.

The present invention provides a clutch between the starter jaw and housing with means responsive to axial movement of the starter jaw to actuate the clutch to a disengaged position. Thus, the starter jaw is restrained from rotation until it has been actuated axially for a predetermined distance.

It is an object of the present invention to provide improved meshing mechanism for an engine starter.

Another object of the invention is to provide an improved starter.

Another object of the invention is to provide improved meshing means for operation at low temperatures.

Another object of the invention is to provide positive meshing means for a starter.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawings wherein two embodiments of the invention are illustrated by way of example.

In the drawing:

Figure 1 is a sectional View of an engine starter embodying one form of the invention.

Figure 2 is a perspective view of the starter jaw of Figure 1.

Figure 3 is a section of an engine starter illustrating another embodiment of the invention.

Referring now to Figure 1, the device therein shown comprises a starter assembly including, in general, a motor I having a driving shaft 2 rotatably supported by a bearing 3 mounted in end Wall 4 of motor housing 5. A pinion 6, shown as integral with the shaft 2 meshes with planet gears The planet gears i are rotatably supported by ball bearings B mounted on stub shafts 9 carried by spider cage It. The planet gears i mesh with a ring gear securely fastened against rotation by screws |2 to gear housing l3. It is understood,

however, that the ring gear may be made integral with the housing l3. The gear housing I3 is secured to the motor housing 5 by screws M as shown or by other suitable means.

Integral with the spider cage I0 is a pinion gear l5 adapted to engage planet gears I6 which in turn engage the ring gear The gears |6 are supported by bearings I! mounted on stub shafts |8 carried by a drum member I9. The drum memher or barrel 9 is rotatably mounted in the housing It by bearing 20.

The barrel |9 is connected for the transmission of rotary motion to axially stationary spline nut 2| through a torque limiting disc pack 22. The disc pack 22 comprises a plurality of friction discs alternately splined to the inner face of the barrel I9 and the outer face of the spline nut 2|. The discs of the pack 22 are forced into frictional engagement with each other by a plurality of circumferentially spaced springs 23 compressed between a flange 24 on the spline nut 2| and an adjustable nut 25 threaded into the barrel l9 and set so that the disc pack 22 will slip at a predetermined torque.

Long lead internal threads 26 of the spline nut 2| mesh with mating threads 21 of screw shaft 28 which is connected to starter jaw 29 by axial splines 39 for rotation therewith. A mesh rod 3| holds the starter jaw 29 into operative relationship with the screw shaft 28. A spring 32 coacts with the mesh rod 3| and screw shaft 28 to effect engagement of the jaw 29 with engine jaw 33 upon axial movement of the screw shaft 28. Also, the spring 32 permits ratcheting upon the engine jaw 33 overrunning the starter jaw 29.

A novel feature of the invention resides in the manner of obtaining and releasing friction for meshing the

jaws

29 and 33. The jaw 29 has a circumferential flange 34 and axial splines 35 (see Figure 2). Disc 33 splined to bafile plate 31 coact with the flange 34 to form an interleaved brake 39. The flange 34 and disc 36 are forced into engagement by helical springs 39 compressed between a plate 49 and a spring retaining ring 4|. The retaining ring 4| is held on the jaw 29 by a split ring 42 fitted in a groove 43 in the splines 35. The spring 39 forces the disc 36 against the flange 34 for frictional engagement with each other.

A sleeve member 44 surrounds the jaw 29 and has fingers 45 extending through openings 46 in the flange 34 between the splines 35. The outer face of the sleeve 44 has a contour substantially similar to that of the jaw 29. A retaining ring 3 41 holds the sleeve 44 in operative relationship with the jaw 29.

Oil sealing means are provided by an oil seal ring 48 carried by a baffle wall 49. The wall 49 is secured between the housing l3 and baffle plate 31. The oil seal ring 46 coacts with the spline nut 2| to provide a seal at one end thereof and an O-ring 56 compressed by a split ring'5l provides a seal at the other end.

In operation, upon the motor I being energized, the jaw 29 is held against rotation by the brake 38 thereby causing axial movement of the jaw 29. Upon the sleeve 44 abutting the engine jaw 33, the fingers 45 force theplate 40 against the spring 39 thereby removing the-pressure of the spring from the disc 36. This removes the friction from the brake with consequent elimination of drag during the starting operation.

Referring now to Figure 3 for another embodiment of the invention wherein only that portion of a starter differing from that shown in Figure 1 is illustrated. Itvwill be apparent how-Figurel could be modified with the embodiment of Figure'3.

The long lead internal .threads of the spline nut 2| mesh with mating threads of screw shaft 55 which is connected to starter jaw 56 by splines '51 for rotation therewith. The jaw 56 is retained in operative engagement by a mesh rod 58 secured to the jaw 55 bya retaining ring 59. A spring'BZ coacts between the mesh rod 58 and the screw shaft 55 to effect engagement of the jaw 56.

The screw shaft 55 is connected to baffle" plate Why an interleavedbrake 6! having disc 62 spline'd to the screw shaft 55 and'disc-EE3 splined to the baffle plate 69. A flange 64 on the baffle plate 60 forms'a backing plate for the clutch 6!. The discs-62 and 63 are forced into frictional engagement by helical springs 65 compressed between the disc pack 6! and a spring retaining ringlifi. -A locking ring 61 retains the ring '66 in operative relationship with the springs 65.

'The retaining ring 66 comprises ring members 68 and 69 having corresponding ramps"!!! and. A ball 12 coacts with the ramps "H1 and H to force the members 68 and 69 apart thus compressing the springs 65.

In operation, the screw shaft 55 is held by the brake 6! against rotation thereby causing it to be 'moved axially towards an engine engaging position. After the shaft 55 has moved axially a predetermined distance, the ball'l2 will'drop in groovel-(i thus permitting the member 68 to move towards the" member 69 to remove the compression from the springs 65. I Upon'the compression pressure on the screw shaft sufficient to pull the ball 12 out of the slot 13 and thereby force the members 68 and 69 apart.

Although'only two embodiments of the invention'haveibeen illustrated and described, various changes in-the form and relative arrangement of the, parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention.

What is claimed is:

1. In an engine starter the combination'ofan assembly comprising an axially stationary rotatable spline nut, a screw shaft in said nut, a starter jaw member adapted for rotation with and axial movement relative to said screw-shaft, a jaw retaining member, spring -means interposed between said jaw retaining member and said screw shaft for urging said jaw member into engagement with an engine jaw upon axial movement of said screw shaft, means including spring biased disc for preventing rotation of said jaw member to effect axial movement of said screw shaft, a sleeve membersurrounding said jaw member and having fingers adapted to 'engage spring biased disc upon engagement of said jaw members to move said disc axially to permit rotation of said jaw members.

2. 'For use in an engine starter having a housing an assembly comprising an axiallystationaryrotatablespline nut, a screw shaft splined to said nut for rotation with and axial movement relative thereto, a starter .jaw member secured tosaid screw shaftfor rotationand axial movement therewith, a spring biased disc connected to said housing, spring meansbiasing said discinto engagement with said starter jaw member and means responsive toaxial movement of said starter jaw member to remove the bias from said disc to permit rotation of said starterjaw.

References Cited in the file of thispatent UNITED STATES PATENTS Number Name Date 1,979,162 Lansing Oct. 30, 1934 2,566,445 Gilbert Sept. 4,1951