US2071539A - Power feed for drilling machines - Google Patents

Description

I E. J. KINGSBURY POWER FEED FOR DRILLING MACHINES Feb. 23, 1937.

7 Sheets-Sheet 1 Filed Sept. '7, 1934 Feb. 23, 1937. KlNGsBURY 2,071,539

POWER FEED FOR DRILLING MACHINES Filed Sept. 7, 1934 v 7 Sheets-Sheet 2 Feb. 23, 1937. E. J. KINGSBURY POWER FEED FOR DRILLING MACHINES 7 Sheets-Sheet 3 Filed .Sgpt. 7, 1934 Feb. 23, 1937. K|NG$BURY 2,071,539

v POWER FEED FOR DRILLING MACHINES Filed Sept. 7, 1934 7 Sheets-Sheet 4 QM/21-W I Ewenfir:

'Feb. 23, 1937. E. J. Kmssumr 2,071,539

POWER FEED FOR DRILLING MACHINES Filed Sept. 7, 1934 7 sheets-sheet 5 Invert/for.-

Feb. 23, 19 37. N B Y 2,071,539

POWER FEED FOR DRILLING MACHINES Filed Sept. 7, 1934 7 Sheets-Sheet s 1937. E. J. KINGSBURY POWER FEED FOR DRILLING MACHINES Filed Sept. 7, 1934 7 Sheets-Sheet 7 Patented Feb. 23, 1937 UNiTED STATES FA'EIENT OFFEQE 8 Claims.

This invention relates to improvements in power feeding mechanism for apparatus such as drilling machines.

One of the features of the present invention is the provision of a power feeding mechanism including a differentiating gearing which operates while the parts turn together to effect a rapid forward traverse movement, and while differentiating action is occurring to produce a slow working feed, in association with clutch means for engaging the gearing with the tool spindle for the forward movements and for disengaging the same to permit a return movement of the spindle.

Another feature of the present invention is the provision of a power feeding mechanism including a continuously rotating body and differentiating gearing including a planet pinion carried bodily with said body; and sun gears, one of which is operatively connected during the forward feeding movement with the spindle feeding elements and the other may rotate freely in one direction for the rapid feeding movement but is prevented from rotation in the other direction and thereby produces a slow working feed through the action of the differentiating gearing.

A further feature of the present invention is the provision of a power feeding mechanism including an element which is moved in proportion to the feeding movement of the spindle and is provided with resilient stops which are adjustable for determining the limits of movement of the spindle, these stops being operative upon the control mechanism which produces reversal of traverse and feeding movements, and mechanism for bringing the spindle to a standstill at the completion of a cycle.

Still another feature of the present invention is the provision of a power feeding mechanism including a selective driving train for producing rapid and slow forward movements, means for returning the spindle when the train is entirely disconnected, and an electromagnetically operable device for producing a connection of the train, along with circuit means for initiating and maintaining the energization of the electromagnetic device during the forward stroke, and interrupting the same at the limit of the forward stroke so that the disconnection occurs and the spindle is withdrawn from the work.

With these and other features as objects in view, as will appear in the course of the following specification and claims, an illustrative form of practicing the invention is set out on the accompanying drawings.

In these drawings:

Fig. 1 is a front view of the mechanism head of the apparatus.

Fig. 1a. is an upright sectional view substantially on line iala of Fig. 1.

Fig. 2 is a left-hand side elevation of the structure in Fig. l, with a guard cover removed, and parts broken away.

Fig. 3 is a corresponding right-hand side elevation.

Fig. 4 is a horizontal section substantially on line 4- 1 of Figs. 1, 2, and 3.

Fig. 5 is an upright section substantially on line 55 of Figs. 2, 3, and 4.

Fig. 6 is a similar upright sectional view on line 6-6 of Figs. 2, 3, and 4.

Fig. 7 is a fragmentary upright section on line 1-1 of Fig. 5, on an enlarged scale.

Fig. 8 is a fragmentary horizontal section substantially on line 8--8 of Fig. 6, on an enlarged scale.

Fig. 9 is a diagram showing the various circuits and the controls associated therewith.

In these drawings the mechanism head of an upright drill is illustrated as having a general housing casting H with proper internal web walls for the mounting and supporting of the parts as disclosed hereinafter, a front wall for receiving certain control structures, right-hand and left-hand side walls with openings therein to be closed by the right-hand and left-hand cover plates RC and LC, and a rear wall including an inclined guideway GW upon which may move a support member SM including upright portions MS on which is fixed a driving motor M as illustrated in my copending application Serial No. 684,063 filed August '7, 1933.

This mechanism head is supported upon a hollow column C which likewise may receive a knee for supporting the work, etc., in the usual manner.

A driving pulley Z0 is keyed or splined on a spindle 2| which is illustrated as extending vertically downward through the head H and supported by appropriate bearing 22 (Fig. 1a) in a quill 23 which is guided for vertical and nonrotating movement in the mechanism head H, and is provided with a rack portion 24 in mesh with the quill pinion 25. The spindle has its lower end projecting from the head H and is connected in suitable manner to a tool such as a drill, for driving the same in rotation.

Likewise, a power-driven vertical shaft 30 (Figs. 2 and 4) is secured to a worm 3!. This worm 3i meshes with a worm wheel 32 (Figs. 5 and 6) which forms part of a rotatable body 33 supported by a bearing 35 upon a cylindrical surface 35 of a fixed shaft 35. An open end of the body 33 is closed by a gear structure 3'1 rotatable relative thereto and supported by bearings 38 engaged on a cylindrical portion 39 of the shaft 36. The body 33 supports the journal pin 40 having a bearing bushing ll and a double pinion 42 thereon: one element of the double pinion engages with the gear teeth 33 on gear member 31, while the other member of the double pinion engages with gear teeth 45 upon the external overrunning-clutch member 45 (Fig. 7), which has a cylindrical internal surface. The overrunning-clutch structure includes a portion 46 of the fixed shaft 36 which has illustratively three notches 47 (Fig. 7) formed therein to receive the clutch rollers 48 which operate between the surfaces of the notches 4'! and the internal cylindrical surface of the clutch member 45 in the normal manner to prevent relative movement in one direction, while permitting a free relative movement in the opposite direction.

' The fixed shaft 36 is supported in a portion Ha of the general housing H of the mechanism head, a key 49 (Fig. 5) being provided to prevent rotation of the shaft 35, and a screw 50 passes through the closing guard cover LC and engages in the shaft 36 for drawing it toward and holding it in the left-hand position (Fig. 5) as determined by the engagement of the shoulder provided by its portion 58 with the axle race of the bearing 34, which in turn engages against the structure Ha. The free end of the shaft 36 is provided with threads 5i for receiving an adjustment nut 52 which engages one of the pressure plates 53 which determine the tension and operation of the spring 54.

The gear member 37 has a cylindrical surface 55 providing a plain bearing for the open end of the body 33, and also the aforesaid gear teeth 43, a surface 55 cooperative with the end surface of the body as a friction means for determining rotation of parts in one direction as will be described hereinafter, and gear teeth 5? of pitch diameter larger than the pitch diameter of gear teeth The axle races of bearings 38 are spaced by a washer 58, and one pressure plate 53 operates to cause these bearings to engage against an internal shoulder 59 of gear member 3'! and cause the friction surface 56 to bear forcibly against the end surface of the body 33. It will be noted that the body 33 has an internal shoulder 68 which limits its leftward movement in Fig. 5, by engagement with the axle race of bearing 3 L The gear teeth 5? of gear member 3? engage with a gear mounted on a bearing sleeve t3 and thus loosely rotatable about the axis of the pinion shaft 51 to which is secured the quill pinion 25 (Fig. 6). This shaft 6! has splines thereon for receiving the clutch member 63 having a groove $9 for engagement by the clutch fork lever Til for moving the clutch member 33 endwise. In one position (Fig. 6) the clutch teeth H engage with corresponding teeth on the gear 65. In a central position, the clutch member 68 is free of any clutch engagement. In a righthand end position the clutch teeth '52 are ongaged with similar teeth on a sleeve l3 which extends through the closing guard plate RC (Fig. 6). Secured externally of the sleeve '53 is a collar '14. Extending from this collar "id is a rod 15. There is an anti-friction bearing E6 between the sleeve 13 and the guard plate RC. When the clutch teeth i2 are moved to the right (upon shifting of the control lever ML as shown in Figure l for producing a movement of the support 19a of clutch lever 70, for ex ple) so as to engage the clutch teeth 13a on t e sleeve, then the shaft 67 is locked to the sleeve 73, and it may be turned manually. When, however, tl "e clutch teeth are released, then the shaft 52 r freely in the sleeve 73. This prev .1 whereby the pinion shaft G'i may be it) the sleeve 73 or may be manually turned thr the aid of the sleeve 13. The shaft 81 is supported in anti-friction bearings l'i carried on peripheral flange extensions of the web wall HB of the housing H. The inner end of the pinion shaft 6'1 has secured thereto a sprocket member '58 which is held in position by a nut l9.

The weight of the spindle, gear and associated parts is counterbalanced by a large .s ht LW (Fig. 3) which may move upwardly and downwardly in the hollow column C, connected to the balance chain BC which p es over a guide sprocket loose on the a driven sprocket 86, the sprocket i8, and a g. sprocket 8?, and is connected at its OLL 1 end to a small weight SW which ma' tains the chain tight. The proper proportionii g of the weights LW and SW permits accurate com ation of the weight of the parts. It is preferi d to have the weight LW sufhciently massive to accomplish an automatic gravitationally-produced raising of the spindle when its power-effected downward feeding movement has been concluded.

The movement of the driven sprocket 88 is employed according to the present invention in determining the limits of upward and downward movement of the spindle. For this purpose as shown in Fig. 5, the sprocket 89 is pinned to a flange piece 95 which in turn is keyed to the reduced end of the shaft 95 and is held thereto by a nut 92. The shaft 9! is journaled in a bushing supported in an internal web wall of the housing H. A pin 94 connects the shaft 9! with a limit member 95 having a radially projecting finger 56 whose path of movement causes it to encounter an inwardly extending lug 9"! located in a groove of a worm wheel $2. A second worm wheel 99 has a lug 586 which is presented in the path of movement of a pin liii carried by the flange member 90. Thus, as the sprocket 86 is driven, the flange member 92"; carries its pin l0! and the member 95 carries its finger 96 in rotational movement with the shaft 9| through a distance which is proportionate to the rotational movement of the gear pinion 25 and hence proportionate to the upward and downward move ment of the spindle itself.

A worm Hi5 meshes with the worm wheel 98 (Figs. 2 and 5) and is fixed on a rotatable and endwise movable control shaft 66 (Fig. 4) by a pin NH. The shaft IE5 is supported by a sleeve tea which in turn is mounted for rotation and axial guiding in a web wall He of the housing H, and is provided with a pin E09 engaged in an axial groove HS of the shaft N35. The sleeve S08 is also guided in an aperture H0 in the front wall of the head H. The front end (at the right in Fig. 4) of the shaft 96 is provided with a collar ill fixed thereto, and operating as an abutment for a coil spring H2 located within an annular space provided in the sleeve I 68, and abutting at its other end against this sleeve for producing a relative leftward movement of the sleeve W8 and rightward movement of the shaft Hlein Fig. 4. The sleeve I08 extends through the aperture Ill! and is provided externally with a flange H3 having a conical peripheral surface which conforms to a similar surface provided on the split supporting ring H4 which is secured to the face of the housing H by screws II5, so that the parts cooperate to prevent a withdrawal of the sleeve I68 from the housing H. A handle plate H6 with a handle lI'i is secured to the flange M3 by screws II8. The flange H3 turns in the split ring H4, and the tightness of its fit may be controlled by adjusting the closing screw I IQ of this split ring.

At its inner end (at the left in Fig. 4) a structure I25, providing spaced collars, is secured to shaft I563 by a pin I28. In Fig. 2, these collars receive between them the pins I2! of a crank lever 23 mounted on a pin I29 extending from the housing structure H, and provided with a pivot connection I39 to a link arm I3I which extends downwardly into a dash pot D which may be adjusted externally of the head. This dash pot and its associated parts may, however, be omitted when the structures are relatively light and the inertia effects are not great.

In similar manner, the worm wheel 99 is in mesh with a worm I35 secured by pin I38 on a shaft I31 which may rotate and move axially. This shaft I31 is supported in a sleeve I38 similar to sleeve I88 and having a pin I39 engaged in an axial groove Mi! of the shaft I31. The end of shaft I38 is provided with a collar I II forming an abutment for a coil spring I42. The end of sleeve I38 projects through an aperture into the upright front face of the housing H and is provided externally of the housing with a flange M3 which has a conical peripheral surface engaged by a conforming internal surface of an annular supporting plate I ls which is secured to the housing H. A handle plate I56 with a handle It? is secured to the flange its by screws Hi3. The rear end (at the left in Fig. 4:) of shaft I3? is operatively connected with a limit switch RL.

The bifurcated clutch lever Ill (Figs. 2 and 6) is pivotally connected at its upper end by a link I58 to a slide member IEI (Figs. 6 and 8) which is guided in the structure HI) and is pivotally connected at its other end to a link I 52 extending from an arm 553 connected by pin I54 to a rock shaft I55 carried by a structure I56 which is aligned by pins I57 (Fig. 3) and secured by screws I58 within the housing H. An upper sleeve I59 rests upon structure IE6 and receives a screw ItIi which engages a groove I6I in the upper end of shaft I55 to hold this shaft against downward movement, while permitting a free rocking thereof. The pivot pin I62 which connects the link E52 with crank arm I53 also receives a link I63 which connects it with the plunger I641 (Fig. 8) of a solenoid ES. This solenoid is illustrated as of the type shown in the copending application of Benjamin N. Foster, Serial No. 741,341, filed August 24, 1934, (now United States Patent No. 1,987,555). When energized, the plunger let draws the arm I53 and link I52 into line so that forces acting in the direction of slide member I5I do not effect any substantial movement. When de-energized, the return spring I 65 operates to break the toggle and permit and assist the return movement of slide member I5I.

The circuit diagram in Figure 9 shows the connection of certain electrical portions in the apparatus. As shown in Figure 1, the apparatus may be provided at the front of the mechanism head with Stop and Start push buttons, at a point where they are easily accessible to the operator.

To start a cycle of movement, the operator depresses the Start push button and this closes (Figure 9) a circuit from a main conductor 23%) through the Start button and conductor 292 to a winding of a control relay CR, and thus back to the other main conductor 2 M. As shown in Figure 3, the relay OR is preferably located within the mechanism head in close association with the other parts of the structure.

The energization of coil 283 causes the relay OR to close and thereby establishes a maintaining circuit from conductor see by conductor 2514, the normally closed Stop button, conductor 2%, limit switch BL, conductor "296, bridge Zis'l of relay CR, and thence through the coil 283 to the main conductor 233i. At the same time the relay CR sets up an initiating circuit from main conductor 2% by conductor 2538, bridge 2B9, conductor 2 I d, the winding of solenoid ES and thus back to the main conductor 28L This solenoid ES is energized and a cycle of movement begins, comprising the downward stroke of the spindle 2I. At the limit of movement, as determined by the feed control system described herein, the limit switch BL is opened. The maintaining circuit through conductors 2%, 285, 2% is interrupted and the relay CE. is de-energized and moves to open position, resulting in a de-energization of the solenoid ES so that this solenoid now operates to release the clutch connection 'II and free the spindle shaft 61 from the feed drive. The spindle it is returned by the gravity action of the weight LW to its upper position and remains therein until the Start button is again depressed. During the return movement of the spindle, the limit switch RL again closes.

It will be noted, however, that the operator has instantaneous control over the apparatus as he may at any time depress the Stop button which is in series with the limit switch RL and thus accomplish an immediate stoppage, in similar manner, of the downward feeding movement of the spindle 2 I, with a return of the spindle to its upward position again by the action of its counterweight LW.

In operation, the attendant releases the split rings I I4 and HM and moves the handles II? and I- li until the desired adjustment of the stop fingers ii? and I96 is attained, for determining the upper and lower limits of travel of the spindle in its feeding movements. The rings I I4 and 54 are then clamped again. The apparatus is thus adjusted to the particular work at hand.

After positioning a piece of work in the usual way, the operator depresses the Start button so that the solenoid ES attracts its core and brings the arm I53 and link I52 into alignment with one another so that they thus operate to move slide member IIiI and rock the clutch lever It so that the clutch elements 'II are engaged. The continuous rotation of the main feed shaft 3% causes the worm SI to rotate the worm wheel 32 and therewith the body 33. During this initial phase of rapid forward traverse movement, the frictional engagement at surfaces 58 causes the body 33 to rotate the gear body 37 at its own speed, this movement being transmitted through gear 35 and clutch elements ll and as and thus to the quill shaft 61 and to the quill pinion 25, and thus the quill and spindle 2i are moved downwardly at a relatively rapid rate while the counterweight LW is raised. The movement of the chain BC causes the sprocket 86 also to be rotated and therewith the shaft 9| with fingers 96 and EM.

When the tool strikes the work and thus a greater resistance is opposed to the downward movement of the spindle 2i and the quill 24, the back pressure exerted through quill pinion 25, shaft gear E5 to the gear teeth 5? overcomes the frictional engagement at surface 56, so that the body 33 overruns the gear body 37. This, however, causes a relative movement of the pin 40 with respect to the gear body 37 and thus the double pinion tends to revolve upon its pin by traveling on gear teeth 43, it. The turning movement, however, tends to cause a relative counter-clockwise movement of the gear teeth 34 about their central axis (Figure '7 which is resisted by the rc-ilers ii). Thus the double pinion G2 is compelled to turn at a rate which is determined, for the particular physical structures, by the speed of movement of the body 33 and this movement is trans ;ted to gear teeth 53 and thus to the gear body It will be understood that suitable numbers of teeth and pitch diameters are employed for gears 53 and 44 and in double pinion :2, according to the relative speed to be attained during this siow workin feed. Thus there may be thirty-two gear teeth &3, thirty-eight gear teeth 54, thirteen teeth on pinion in mesh with gear teeth and sixteen teeth on pinion 2-2 in mesh with gear teeth 55-, to give a ratio of 28.44 to 1 between rapid traverse and slow working feed movements. The continued upward movement of the gear body 3?, but at the lesser rate continues to produce a downward movement of the spindle 2i at a consonantly lesser rate, and the tool is advanced into the work at this rate.

This working feed continues until the finger ifil encounters the lug let on worm wheel 99 and causes a. rotation of the worm wheel 99. This rotation is transmitted to the screw I35 and causes a movement of the rod 535 against the action of spring Hi2, and results in the opening of the limit switch RL, and thus determines the nature of the downward movement of the spindle M.

The solenoid is de-energized and the clutch elements ii are moved out of engagement as deibed above, so that the shaft 6? is now fed from the power drive from shaft 3! and is reti ned by its counterweight LW which at the some time operates to move the shaft 9| backwardly. The limit of this backward movement is determined by the engagement of finger 98 with lug 91, causing a slight rotative movement of the worm wheel 98 which is transmitted to screw 26?: and absorbed by spring H2. As illus- :1, this action may be dampened by employ ne dash pot system 528-43! and dash pot D.

The cessation of the resistance back through the gear train and gears 6557 permits the frictional surface to operate again and the difierential system including the body 33 and its parts then causes the gear body 3'1 to turn with an equiangular movement as before.

The sensitiveness of translation from the rapid forward traverse to the slow working feed is dete mined by the compression of spring 54 as adjusted by nut 52.

It is obvious that the invention is not limited solely to the form of construction shown but that it may be modified in many ways within the scope of the appended claims.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. A device of the class described, comprising a frame, a member to be advanced relative to said frame at varying predetermined speeds, a shaft having an overrunning clutch surface and means for preventing retrograde movement of the shaft relative to the frame, a differentiating gear train including a body rotatable about said shaft and having an eccentric pivot, a first sun gear freely rotatable about said clutch surface in one direction, a second sun gear connected with said member, and a double planet pinion on said pivot and meshing with said gears and operative to produce a retrograde effect upon said first sun gear relative to said shaft when said body moves relative to said second sun gear, said second sun gear having friction means cooperative with said body for effecting a conjoint equiangular movement of the body, pinion and sun gears when the resistance to movement of said body is less than a predetermined value for producing a high advancing speed of said member, and clutch means cooperative with said clutch surface and said first sun gear to prevent retrograde movement thereof by said planet pinion when the said resistance exceeds said predetermined value so that the differentiating train produces a slow advancing speed of said mem her.

2. A device of the class described comprising a frame, a member to be moved downward relative to the frame, counterbalance means for returning the member upwardly, a shaft and means for preventing retrograde movement of the shaft relative to the frame, a body moved in rotation, a first sun gear freely rotatable in one direction about the shaft, a second sun gear rotatable about the shaft, a double planet pinion pivoted on said body and in mesh with said gears and operative to produce a retrograde movement of said first sun gear relative to said second sun gear when said body moves relative to said second sun gear, said second sun gear having friction means cooperative with said body for efiecting a conjoint equiangular movement of the body, pinion and sun gears when the resistance to downward movement of said member is less than a predetermined value, connecting means including a first clutch for connecting said second sun gear for moving said member downwardly, and clutch means engaging the first sun gear and shaft to prevent retrograde movement of said first sun gear relative to said shaft when the said resistance exceeds said value, said first clutch being effective in one position for connecting said second sun gear and member for producing a downward movement of said member and when in another position serving to interrupt said connection so that the counterbalance means may return said member to its raised position.

3. A device of the class described, as in claim 2, including means actuated by the member at a predetermined position of downward movement for moving said clutch to the interrupting position.

4. A device of the class described, as in claim 2, including a circuit closer, electromagnetic means for moving said clutch to connecting position, and circuits connecting the closer and electromagnetic means including means for maintaining the energization of the electromagnet during the downward movement of said member, and means operated by said member at a predetermined position of downward movement for deenergizing said electromagnet so that said clutch will move to interrupting position and said counterbalance means will return said member.

5. A device of the class described comprising a frame, a member to be advanced relative to the frame at varying predetermined speeds, a shaft fixed to the frame, an element moving about the shaft continuously in the same direction, a first gear journaled on the shaft for turning freely with said element in a forward direction, means forpreventingretrogrademotion of said first gear relative to the frame, a second gear journaled on the shaft, means including a clutch for connecting said second gear to said member to produce advancement of the latter, friction means for causing said element and second gear to turn together when the resistance to advancing movement of said member is below a predetermined value, means cooperating with said element and said gears for producing a relative retrograde effort on said first sun gear when said resistance exceeds said value and thereby operating for effecting a slow continued advancing movement of said second gear and member, and means operated at a predetermined point of advancement of said member for disconnecting said clutch.

6. A device of the class described comprising a frame, a member to be advanced relative to the frame at varying predetermined speeds, a shaft fixed to the frame, an element revolving about the shaft continuously in the same direction and at substantially the same velocity, a first gear journaled on the shaft to turn freely with said element, clutch means on the shaft and first gear effective at all times for preventing retrograde movement of said first gear relative to said shaft, a second gear connected for moving said member, constantly operating friction means for causing said element and second gear to turn together at a rapid rate when the resistance to movement of said member is below a predetermined value, and means cooperating with said element and said gears for producing a relative retrograde effort on said first gear when said resistance exceeds said value and thereby cooperating with said preventing means for effecting a slow continued advancing movement of said second gear and member.

'7. A device of the class described comprising a frame, a member to be moved relative to the frame, a shaft fixed to the frame, an element revolving about the shaft continuously in the same direction and at substantially the same velocity, planet pinion means carried bodily in movement with said element, a first sun gear in mesh therewith and freely revcluble about the shaft in the direction of movement of said element, clutch means on the shaft and first gear for preventing retrograde movement of said first sun gear relative to the shaft, a second sun gear having a lesser number of teeth than said first sun gear and in mesh with said planet pinion means and having constant frictional engagement With said element to be turned at equiangular velocity therewith when the resistance to movement of said second sun gear is less than a predetermined maximum, and means connecting said second sun gear and member for advancing said member, said planet pinion means operating to produce a retrograde movement of said first sun gear relative to said second sun gear when the resistance exceeds said maximum.

8. A device of the class described comprising a frame, a member to be advanced relative to the frame, a shaft fixed to the frame, a revoluble element providing a planetary body and means for driving the same rotation about the shaft, planet pi on means eccentrically mounted on said planetaly body, two sun gears each in mesh with said planet pinion means and each rotatable about the shaft, devices connecting said one sun gear with said member to advance the same, friction means for causing said body to turn one said sun gear and devices and advance said member at a fast rate so long as the resistance to advancement of said member is below a predetermined maximum, said body, pinion means and sun gears being constructed and arranged for producing a relative forward movement of the said one sun gear relative to the other said sun gear upon slippage of said friction means, and overrunning clutch means on the other said sun gear and the shaft for preventing retrograde movement of said other sun gear relative to said shaft whereby to cause a slow rate of advancement of said member by said devices, said overrunning clutch means operating to permit movement of said other sun gear with the planetary body during drive through said friction means.

EDWARD JOSLIN KINGSBURY.

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