US2015131A - Starter gearing - Google Patents

Description

Sept 24 w M.Y P. WHITNEY' MSNM v i. STARTER GEARING Filed June 14, 1935 3 Shees-Sheet l wmp/65:

V` i I .4 1 7mm/E) Sept1 24, H935. M. 1:l WHITNEY STARTER GEARING Y Filed June 14, 1933 A 3 Sheets-Shf.=,e'rl 2 f NVENTOR Y M 2f.

ATTORNEY Sep" 24 M. P. WHITNEY STARTER GEARING Filed June 14, 1933 3 Sheets-Sheet 5 /N VEA/TOR l mms- M f l ATTORNEY Patented Sept. 24, 1935 PATENT OFFICE STARTER GEARING Maurice P. Whitney, Elmira, N. Y., assigner to4 Eclipse Machine Company, Elmira Heights, N. Y., a corporation of New York Application June 14, 1933, Serial No. 675,741

15 Claims.

This invention relates to starter gearing and more particularly to a drive for automatically connecting and disconnecting a starting motor with a member of an engine to be started.

It is an object of the present invention to provide -an engine starter drive which is small and compact but of rugged construction and highly eicient in operation.

It is another object to provide such a device embodying provisions for securing continuous cranking until the engine starts.

A further object is to provide' such a device which incorporates structure for preventing the transmission of any substantial driving eiect from the engine to the armature of the starting motor.

It is a further object to provide such a device' in which means are incorporated for ensuring proper engagement between the engine driving member and the member of the engine to be driven.

It is an other object to provide such a device having ample torque capacity but which is not liable to stick or jam.

It is another object tol provide such a device in which the kinetic energy of the engine driving member and associated parts at the time of disengagement from the engine member is dissipated in friction of slipping clutch surfaces in a manner to preventrebounding of the parts toward operative position.

A further object is to provide such a device' which is entirely self-contained as a simple unit which may be readily slipped on a motor shaft and xed thereto. v

Further objects and advantages will be apparent from the'following description taken in4 connection with the accompanying drawings in which:

Fig. 1 is a side elevation partly in section of a preferred embodiment of the invention show ing the parts in their normal idle position.

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

Fig. 3 is asimilar view showing the parts in the positions assumed when the engine drivingv member abuts against the member of the engine to be started instead of properly meshing therewith.

Fig. 4 is a perspective view of the engine driving member and the parts associated therewith, the various elements being shown in extended Ydisassembled relation.

Fig. 5 is a similar view of the screw shaft and its associated parts.

Fig. 6 is a view similar to Fig. 1 ofa second embodiment of the invention. I

Fig. 7 is a similar view showing the parts in driving position; and

Fig. 8 is a perspective view of a preferred form 5 of a barrel member for connecting the driving clutches with the engine driving member as i1- lustrated in Figs. 6 and '7.

Referring first to Fig. 1 of the drawings, there is illustrated a power shaft I which may be the 10 extended armature'shaft' of a starting motor,

not illustrated. An engine driving member in the form of a pinion 2 is freely journalled on the power shaft I inv position to be moved longitudinally into and out of engagement with a mem- 15 ber 3 such as a flywheel gear of the engine to be started.

Means are provided for moving the pinion 2 into and out of engagement with the engine gear 3 and for rotating the pinion to drive the engine 20 gear comprising a, hollow shaft i adapted to be suitably fixed to the power shaft I vas by means of a key 5 and set screw 6 and having stop members 8 and 9 suitably fixed to its respective ends, a barrel member I3 fixed to the pinion 2, and a 25 friction clutch including a driving cone element II having an inclined plane connection with the shaft'and a driven cone element I2 splined to the barrel. As here illustrated, the inclined plane connection yis provided by reducingv and thread- 30 ing a portion of the shaft as indicated at l, and threading the driving element thereon, and vthe splined connection vis formed by means of radially extending teeth Id on the driven clutch element i2 slidably engaged in longitudinal slots v35 I5 in the barrel i3. The slots i5 terminate at shoulders i6 forming a positive limit for the telescoping movement of the clutch element i2.

The driving clutch element I i is retained within the barrel I3 by suitable means such as a re- 40 taining disk I 'i having radially extending portions I8 engaging in the slots I5, and a lsplit ring I S arranged to be sprung within a fiange 2i formed on the end of the barrel I3. It will Ahe noted that the clutch elements are so dimenthrustring 26 which bears against the radially extending teeth I4 of the outer clutch element I2. Since the inner clutch element II is retained in the barrel by the disk I1 andthe clutch element I2 is spaced from said disk as abovedescribed, it will be readily appreciated that the pressure of spring 23 maintains the clutch elements in frictional engagement at all times.

Load responsive means for compressing the clutch elements II, I2 for the transmission of cranking torque is provided in the form of a comparatively heavy compression clutch spring 21 within the barrel I3 normally engaging the outer clutch element I2 at one end and bearing at its other end against a thimble 28 which is slidably mounted on the smooth portion of the hollow shaft 4 and has-a loose sliding iit within the barrel I3. The thimble 28 normally bears against a shoulder 29 in the interior of said barrel being maintained in engagement therewith by a comparatively light compression spring 3| located between said thimble and the stop member 8.

In order to attach the pinion 2 to the barrel,

.the pinion is provided with a flange member 32 suitably fixed thereon as by means of inwardly extending teeth 33 formed to engage a turned down portion of the teeth of pinion 2 and clamped between a shoulder 34 at the end of such turned down portion and a ring 35 which is riveted against the flange by peening over the end of the pinion 2 as shown at 36. The rim of the ilange 32 is provided with axially extending fingers 31 arranged to engage in slots 38 in the end of the barrel I3, and suitably retained therein as by means of a split ring 39 which is sprung under a retaining flange 4I (Fig. 2) of the barrel.

It will thus be seen that the pinion 2 is rigidly A connected to one end of the barrel I3, while the clutch I I, I2 is splined to the other end, the pinion and barrel assembly being retained in its idle position'by the anti-drift spring 3l. The idle position of the drive is dened by the stop 8 which is illustrated as a sleeve threaded on the outer end of the hollow shaft 4 and retained thereon by the set screw 6.

Means are provided for maintaining continuous cranking until the engine starts, in the form of a centrifugal device which holds the pinion 2 in mesh with the engine gear 3 until rendered inoperative by rotation of the pinion and barrel assembly above a predetermined speed. As here shown this device comprises a plurality of latch members 43 slidably mounted in openings 44 in the barrel and normally projecting therein suiilciently to engage a radial flange 45 on the stop member 8 when the pinion 2 is in operative position as illustrated in Fig. 2. The flange 45 and the latch members 43 are bevelled on one side as indicated at 46 and 41 respectively so that the latch members pass over the flange freely during the meshing movement of the pinion 2. Thereafter the latches are urged inwardly by suitable the barrel as shown at 49 whereby the latches maintain the pinion in driving position during cranking. When the barrel I3 rotates at sufficient speed, however, the centrifugal force of the latch members 43 overcomes lthe pressure of the springs 48 causing the latches to be retracted out of engagement with the flange 45. The pinion assembly is thereupon free to move to idle position under the influence of the spring 3l. 'I'he outwardv motion of the latch members 43 under the influence of centrifugal force is limited by Suitable means such as the shouldered screws II xed to the barrel I3.

In the operation of this embodiment of the invention, rotation of the power shaft I from the starting motor causes the rotation of the hollow 5 shaft 4, and since the clutch element II is prevented from rotating therewith by reason of its frictional engagement with the clutch element I2 and the inertia of the clutch and pinion assembly, the clutch element II is caused to traverse the 10 screw threads I whereby the barrel and pinion assembly is moved longitudinally to mesh the pinion with the engine gear as shown in Fig. 2. After meshing is completed, further longitudinal motion of the barrel and pinion assembly is pre- 15 vented by the engagement of the thimble 28 with the stop member 8 on the screw shaft whereupon the further rotation of the power shaft causes the clutch II, I2 to move longitudinally in the barrel I3 compressing the spring 21 against the 20 thimble 28 until sufficient torque has been built up through the screw jack action of the triple threads working against the compression of spring 21 to equcl the torque resistance of the flywheel and thereby cause rotation of the pinion to crank 25 the engine.

During the cranking operation, it will be'understood that variations in the load on the pinion 2 caused by the engine passing over its compression points may cause the clutch elements II, I2 to 30 hunt back and forth along the threads 1 to some extent, but the pinion is held in full mesh with the engine gear by virtue of the splined connection of the clutch I I, I2'on the barrel I3 which permits the clutch to move back and forth in the barrel. 35 as well as by the latch members 43 which are maintained in position to engage the flange 4l at all cranking speeds and positively hold the pinion in cranking position. y

When the engine starts, the acceleration of the 40 engine gear causes the pinion to overrun the power shaft whereby 'the clutch II, I2 is moved back to idle position, relaxing the pressure of the spring 21 thereon. The driving effect of the engine gear on the pinion 2 thereafter causes the 45 clutch II, I2 to overrun which permits the barrel to be accelerated to suillcient speed to move the centrifugal latches 43 to inoperative position. The spring 3I thereupon becomes effective to move the pinion and barrel assembly to idle position.l50

It will be noted that during the time that the flywheel is driving the pinion, the armature of the starting motor is substantially disconnected from the pinion, so that no appreciable driving eifect is transmitted to the armature.

In case during the engaging operation, a tooth of the pinion comes into abutting relation with a tooth of the engine gear so that the longitudinal motion of the barrel is stopped, continued longitudinal movement of the clutch II, I2 comco presses the spring 23 as shown in Fig. 3, thereby storing up energy in said spring for snapping the l resilient means such as the springs 48 attached to pinion into mesh with the nywhl when the teeth are properly indexed, and correspondingly comsembly is projected forward Lby the expansion of terval to allow the indexing to take place, and

the spring serves to snap the pinion into initial meshi'ngrelation as soon as the indexing takes place, whereby milling of the pinion teeth against the teeth of the engine gear is prevented.

The spline slots I5 in the barrel are preferably formed of such length that the thimble 2,8 engages the stop in case of tooth abutment before thev clutch element I2`engages the shoulders IB so that the main clutch spring 21 is compressed somewhat, and the clutch correspondingly tightened prior to the positive closure of the clutch due to the engagement of the clutch element I2 with said shoulders.

It will be readily appreciated that the pinion and barrel assembly, with the clutch element l2 has considerable rotational inertia so that the demeshing action thereof is brought about not only by the spring 3i but also by the drawing action of the clutch element II which is frictionally connected to the barrel by virtue of the pressure of spring 23, and is therefore caused to overrun the screw shaft .4. When the clutch element II strikes the stop 9, further backward motion of the entire assembly is prevented, but any tendency to rebound toward the engine gear is suppressed by reason of the fact that the continued rotation of the pinion and barrel causesl the clutch element I I to be firmly held against the stop 9 whereby the disk I'l effectively holds the barrel and associated parts in idle position.

In Figs. 6, 7, and 8 there is illustrated another embodiment of the invention providing for additional torque capacity of the drive without increasing the size or weight of the parts thereof As here shown the elements of the pinion and barrel assembly, the clutch and screw shaft are the same as in the embodiment first described and are similarly numbered, but the thimble 28@ and the stop 8@ which form the abutment for lthe main vclutch spring 21 are formed in the shape of cooperating clutch elements, and the thimble 230 is provided with radially extending key elements i slidably mounted in slots 282 in the barrel I3. The spring 3i normally maintains the key elements 28| of the thimble 280 against the shoulders 290 formed by the ends of the slots 262, thus performing its anti-drift function as in the first embodiment. However, since the clutch thimble 220 is splined as above described to the barrel I3, the barrel is connected to the hollow shaft t by the clutch formed by the elements Bil and 280 as well as by the clutch il, I2, when the meshing motion of the pinion and barrel assembly compresses the spring 21 between the driven elements 28@ and I2 of said clutches.

The barrel may beformed as indicated in Fig. 8 from a sheet metal blank which'is stamped out and then rolled and locked together by suitable vmeans such as the dove-tail joint I 30 as shown.

In this case the locating ange for'the ring 24 corresponding to the flange 25 in the rst embodiment of the invention is preferably formed as a series of struck up portions 250 which serve to locate the ring 24 and hence form an abutment for the spring 23.

The operation of this embodiment of the invention is the same as that previously described except for the additional clutching effect be.- tween barrel and hollow shaft caused by the additional clutch elements 80 and 280. This per- 5 mits the use of somewhat steeper angles for the clutching surfaces whereby any possible danger of wedging and jamming of the clutches is prevented.

What is claimed is: 10 l. In an engine starter, a power shaft, a hollow screw shaft fixed thereto, a friction clutch having a threaded connection with the screw shaft, a member. movably mounted on the power shaftto engage and drive a member of the engine l5 to be started, connections including a barrel member for actuating the engine driving 4mem-- ber from the clutch, a stop member on saidscrew shaft, and a compression spring on the screw shaft between the clutch and stop member ar- 20 ranged to be compressed therebetween by further movement of the clutch on the screw shaft after the engine driving member has been moved to operative position.

2. In a starter drive, a shaft, a friction clutch 25 comprising a driving element, means connecting Saiddriving clutch element to said shaft for concmitant rotary and longitudinal movement thereon and rotation therewith, a pinion freely mounted cn the shaft to engage and drive an 30 engine gear, a barrel member fixed to the pinion, said clutch having a driven element splined to the barrel, a positive stop for the barrel in its operative position and yielding means engaging said stop for limiting the movement of the driven 35 clutch element in the engaging direction whereby further movement of the clutch after the barrel engages said stop causes tightening thereof to transmit cranking torque.

.3. In a starter drive, a shaft, a friction clutch w comprising a driving element, means connecting said driving clutch element to said shaft for eon-V comitant rotary and longitudinal movement thereon and rotation therewith, a, pinion freely mounted on the shaftito engage and drive an engine gear, a barrel member xed to the pinion, said clutch having a driven element splined to y the barrel, an abutment xed relative to said shaft Within said barrel, a thrust member slidably carried by saidshaft within said barrel, said barrel having means for limiting the sliding movement of the thrust member therein, means interposed between the abutment and thrust member for yieldably spacing the same and holding the thrust member against said limiting means, and means for yieldingly holding the thrust member and the driven clutch member in spaced relation.

4. In an engine starter, a power shaft, a hollow screw shaft fixed thereto, a member slidably journailed on the power shaft to engage and drive a member of the engine to be started, a clutch comprising a driving element having a threaded connection with the screw shaft, and a driven element, means including a barrel member for connecting the-driven clutch element to the engine driving member, said screw shaft having an abutment, a light compression vspring and a heavy compression spring on the screw shaft between the clutch and abutment, said light spring serving to normally maintain the parts in idle position, and said heavy spring serving to close the clutch for the transmission of driving torque after the parts have been moved to driving position.

' 5. In an engine starter drive, a power shaft, an engine driving member mounted for longitudinal movement thereon into. and out of engagement with a member of the engine to be started, and for rotary movement therewith to drive said engine member, means for actuating the engine driving member from the power shaft including a clutch, means connecting said clutch to said shaft for rotary and longitudinal movement thereon and rotation therewith, and a barrel member non-rotatably connected to the engine driving member and clutch, a thimble having limited sliding movement within the barrel, a stop for the thimble mounted on the shaft, a spring between the thimble and stop normally holding the drive in idle position, and a spring between the clutch and thimble arranged to be compressed when the thimble engages the stop to thereby tighten the clutch.

6. In a starter drive, a shaft, a friction clutch comprising a driving element, means connecting said driving element to said shaft for rotary and longitudinal movement thereon and rotation therewith, a pinion freely mounted on the shaft -to engage and drive an engine gear, a barrel member xed to the pinion, said clutch having a driven element splined to the barrel, and means normally holding said barrel and clutch in extended relation, said means being adapted to yield and allow telescoping thereof in case of tooth abutment between the pinion and gear, and

means for thereafter tightening said clutch for transmission of indexing torque.

'7. In a starter drive, a shaft, a friction clutch comprising a driving element, means connecting said driving element to said shaft fory rotary and longitudinal movement thereon and rotation therewith, a pinion freely mounted on the shaft to engage and drive an engine gear, a barrel member xed to the pinion, said clutch having a driven element splined to the barrel, and means normally holding said barrel and clutch in extended relation, said means being adapted lto yield and allow telescoping thereof in case of tooth abutment between the pinion and gear, said barrel having 'a retaining member for the driving element of said clutch whereby the holding means serves to maintain the elements of the clutch in frictional engagement.

8. In an enginestarter drive, a power shaft, ay,

pinion freely joumalled thereon for longitudinal movement into and out of engagement with a gear of an engine to be lstarted and for rotation therewith to crank said engine, means for actuating the pinion from the power shaft including a barrel member xed to the pinion, a friction clutch splined to said barrel and means connecting said clutch to said shaft for rotary and longitudinal movement thereon and rotation therewith, yielding means for closing said clutch and for limiting the travel of said clutch, and yielding, means for opposing the longitudinal movement of the clutch with respect to said barrel.

9. In an engine starter drive, a power shaft, a

" pinion freely journalled thereon for longitudinal' movement into and out of engagement with a gear of an engine to be started and for rotation therewith to crank said engine, means for actuating the pinion from the power shaft including a barrel member fixed to the pinion, a friction clutchsplined to said barrelv and means connecting said clutch to-said shaft for rotary and longitudinal movement thereon and rotation therewith, clutch controlling means for limiting the travel of said clutch and serving to tighten the clutch for the transmission of cranking torque, and yielding means for opposing the longitudinal movement of the clutch with respect to the barrel, the parts being so arranged that in case longitudinal movement of the barrel is prevented by the tooth abutment between the pinion and gear. the yielding opposing means is initially compressed before the clutch reaches the limit of its movement. 1

-10. In an engine starter drive, a power shaft, a driving member mounted thereon, means for moving the driving member into and out of engagement with a member of the engine to be started, means for rotating the driving member from the power shaft including an overrunning connection effective independent of translational movement of the ydriving member, means for holding said driving member in engagement with the engine member, and mounting means for said holding means normally maintaining said holding means in operative position but adapted to yield at a predetermined rotational speed of the drive and permit the holding means to move to inoperative position responsive to centrifugal force. s

1l. In an engine starter drive, a power shaft, a drivingmember mounted for movement thereon into and out of engagement with a member of the engine to be started, means for rotating the driving member from lthe power shaft including a friction clutch and load responsiver means for tightening said clutch, means for holding said driving member in engagement with the engine member, and mounting means normally maintaining said holding means in operative position but adapted to yield at a predetermined rotational speed of the drive and permit the holding meansto move to inoperative position responsive to centrifugal force.

l2. In a starter drive a powershaft, an engine driving member and a driving connection therebetween including a pair of friction clutches, yielding means normally closing one clutch and yielding load responsive means for tightening both clutches for the transmission of cranking torque. f

13.A In a starter drive for internal combustion engines, a power shaft, a member movable thereon into 'and out of engagement. with a member of the engine to be started, and means for actuating the engine driving member from the shaft including a driving clutch element, means connecting said driving clutch element to said shaft for rotary and longitudinal movement thereon and rotation therewith, a driven clutch element non-rotatably connected to the engine driving member, a yielding element in the path of movement of the driven clutch member, a stop fixed relative to said shaft and an abutment cooperating therewith for limiting'the longitudinal movement of the yielding element to thereby yieldln'gly limit the longitudinal movement of the clutch, said stop and `abutment comprising .additional clutch `members connected .respectively .to .the power shaft and engine driving member.

14. In a starter drive for internal combustion engines, a power shaft, a member movable there- .on and therewith to engage and drive a member of the engine to be started, and means for ,actuating the engine driving member from the power shaft including a pair of driving clutch elements connected to be rotated by the shaft, a pair of driven clutch elements having a splined connection with the engine driving member, mean;

for holding a driving anda driven clutch element in initial engagement, and yielding load responsive means for causing driving engagement of all the driving and driven clutch elements.

15. In an engine starter drive, a power shaft, a driving member mounted for movement thereon into and out of engagement with a member of the engine to be started, means for rotating the driving member from the power shaft including an overrunningl connection effective 'independent oi' translational movement of the drive ing member, a centrifugal detent for holding the driving member in operative position, and mounting means for said detent normally maintaining said holding means in operative position but adapted to yield at a predetermined rotational speed of the drive and permit the holding means to move to inoperative position responsive to centrifugal. force.

MAURICE P. WHITNEY. l0

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