US2608966A - Hydraulic starter - Google Patents

Description

p 2, 1952 A. c. JENNY HYDRAULIC STARTER 2 SHEETS-SHEET 1 Filed May 24 1951 ATTORNEY Sept. 2, 1952 A. c. JENNY 2,608,966

' HYDRAULIC STARTER Filed May.24, 1951 2 SHEETSSHEET 2 N i A, O N RI; 2/ "2| g,

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ALBERT c. JENNY MAW ATTORNEY Patented Sept. 2, 1952 UNITED STATES PATENT 0F HYDRAULIC STARTER Albert C. Jenny, ClevelandLl'Ohio, assignor to Jack & Heintz Precision Industries, Inc, Cleveland, Ohio, a corporation of Delaware 7 Application May24, 1951 Serial No. 228,605,

This invention relates in general to hydraulic starters for engines and more particularly to that type of starter employing a rotating cylinder.

In starter drives of the hydraulic type','it is conventional practice to so construct and arrange the hydraulic motor, drive and porting plate as to provide for the extension of the starter pinion into full mesh with the engine flywheel ring gear prior to any rotation of the drive shaft and to then suddenly initiate a full speed rotation of the motor and drive thereby of the drive shaft.

It is particularly true in hydraulic motor starters that a straight linear extension of the starter pinion, with no rotation thereof, will not insure proper mesh of the pinion with the ring gear, inasmuch as there is always the possibility of head-on engagement of the teeth without proper mesh. This not only means lack of engagement but also presents the danger ofteeth .chattering and destruction when full speed rotation of the motor and drive shaft are applied without previous full pinion and ring gear" mesh. Accordingly, one of the primary objects of my invention is to provide in such a device a meter ing means for the hydraulic system whereby as the starter pinion is being extended, the motor operated drive shaft will be slowly rotated until the starter pinion and engine flywheel ring gear are fully meshed, after which time afull flow of hydraulic fluid is fed to the motor to obtain full speed rotation of the motor and its drive shaft.

Another object is to provide in such a hydraulic pressure system, involving a pinion and piston normally spring retracted, a fluid control to cushion the forward travel of the pinion extending piston and a fluid control to force the piston forward and simultaneously cause slow rotation of the motor and'drive shaft to obtain full mesh with the engine ring gear before full rotation of the motor, drive shaft and the meshing gears.

Another object is to provide in the hydraulic system a fluid metering system that will, upon operation of a suitable manual control, not only insure linear extension of the starter pinion by the piston and simultaneous slow rotation of the pinion by the motor until full mesh with the engine ring gear and thencause full speed rotation. of, the motor andstarter pinion, but will also prevent reengagement'of the starter pinion with. the engine flywheel ring gear, after the starting of the engine has kicked the starter pinionqout of mesh, even though the operator 3 Claims. (01. izaqnn 2 inadvertently continues to apply the manual control which initiated the engine starting operation. l

'With'the foregoing and other objects in View, the invention resides in'the combination of parts and in the details of construction hereinafter set forth in the following specification and appended claims, certain embodiments thereof being illus-s trated in the accompanying drawings, in which: Figure 1 is a view in longitudinal section taken through the hydraulic starter assembly, showing the same in retracted position; Figure 2 is a viewin end elevation of the port ing plate; l

Figure 3 is an enlarged detail sectional view taken along line-3 of Figure 2,"through the engaging head casing; s a

- Figure 4 is an enlarged detail sectional view taken along line 4-4 of Figure 2g-and Figure 5 is a'view similar to Figure 1, showing the starter assembly in extended position.

Referring more particularly to the drawings; the hydraulic starter is shown to-includean engaging head casing I, a porting plate 2 and a hydraulic motor casing 3. Suitable securing means may be employed to fasten the casings and porting plate together.

Positioned axially within the starter is a rotatable shaft 4 which is carried at one end in a bearing 5 of casing I and at the other end by a bearing 6 of casing 3. A wobble plate 1- is carried between shoulders 8 and 9 by means oia ball bearing assembly H1. The wobble-plate l is press fitted into the inner race It and the draulic fluid from a suitable source, such asan; accumulator, the fluid flow being under conventional manual control. Inlet l6 communicates with an arcuate inlet'port I! in the porting-plate 2. An exhaust port H3 in casing l communicates with an arcuate outlet port IS in porting plate 2.

Slidably, mounted in casing l is a piston 20 with a reduced hollow stem 2| .to leave a chamber 22 in the casing about the piston stem. Surrounding stem 2| is a compression coil spring.

23 that bears against casing shoulder 24- and the piston 20 to normally force the piston fully to the right into the retracted position of Figure 1.

Shaft 4 is provided with helical threads 25 to be engaged by the starter pinion 26 which is normally held in the retracted position of Figure 1 by a compression coil spring 2! bearing against a shaft collar 28 and against the pinion to urge the latter to the right against a plate 29 and the latter against the front, or left, end of the piston stem 2 I.

In the at rest retracted position of Figure 1 with the hydraulic motor stationary, the reduced passage l6, from the hydraulic inlet [6, slightly overlaps in communicating relationship with a radial port 3| in piston 2|] that communicates with a longitudinal passage 32 leading to chamber 22 and through a restricted longitudinal passage 33 into chamber 30 behind the piston.

When the conventional starter control valve is manually opened, the hydraulic fluid is released from its accumulator to flow under pressure through the inlet I6, and inlet port It, and through passages 32 and 33 into chambers 22 and 30. The larger passage 32 lets fluid into chamber 22, in which spring 23 is located, to provide a dashpot for the forward movement of the sleeve piston 20. The relatively smaller passage 33 meters the fluid flow at a reduced rate into chamber 30 on the back face of the large diameter of the sleeve piston head. This fluid pressure forces the piston, and consequently the starter pinion 26, linearly forwardly to the left into meshing engagement with the engine flywheel ring gear 45, as shown in Figure 5. This operating of the sleeve piston is afiected by the differences in the pressure areas between the sleeve and shaft diameters, which makes the sleeve a differential piston. The sleeve also operates against two springs 23 and 21 which reduces the rate at which the sleeve is extended and aids in retracting the pinion after the engine cranking cycle is completed.

Leading to the inlet port H is an inlet passage 34 that is normally closed from passage It by the piston head. Leading from chamber 22 to passage 34 is a restricted passage 35 in the piston head. Also located in a bore in the piston head is a poppet valve 36, spring urged to the right to open by a compression coil spring 31 and leading from the bore in which the poppet valve is located is a passage 38 leading to inlet passage 34 to the hydraulic motor. The function of the poppet valve in the hydromesh sleeve piston is to allow fluid trapped at the large head end of the piston to escape to the motor and to let the sleeve return quickly so as to allow the starter pinion to get out of mesh quickly after the engine has been started. a a

With less than 125 pounds per square inch in the pressure passages, the pinion and sleeve spring push the sleeve all the way back into the retracted position of Figure l, forcing the' poppet valve against the porting plate 2, holding it closed against its seat against the action of spring 31. This is the condition before the cranking cycle.

, When fluid pressure is admitted sufficient to start pushing the sleeve outwardly to the left, this fluid, pressure holds the poppet valve closed against its seat and the poppet valve remains closed until the sleeve pushes out and uncovers the main passages. At this point the pressure on both sides of the poppet valve becomes equal and spring 3! acts to open the poppet valve. The poppet valve will remain open until the main .manual control valve is closed, at which time the spring pressure on the sleeve will seat the poppet valve upon its abutment with the porting plate. In other words, if the operator opens the control valve to start the engine and holds the valve open after the engine starts the starter pinion will withdraw from the engine flywheel ring gear and continue to revolve slowly in a neutral unmeshed position. This 'is' accomplished by spacing the poppet valve port with respect to the motor intake port 34 so that it will cut oil? the main fluid flow at approximately one sixteenth of an inch from the point of closing of the poppet valve and continue to bleed off the pressure fluid through to the motor without changing the hydromesh sleeve position. Any

discontinuance in fluid pressure from the main manual control will allow the sleeve to drift back and reset the poppet valve for another engine cranking operation of the assembly.

As an added precautionary refinement, I provide in the main casing l a longitudinal bore 39 communicating through a radial passage 40 with chamber 22. In 'bore 39 I insert a screw plug 4| having a passage 42 therein and a seat to accommodate a ball 43 normally urged against the seat by a compression coil spring 44 to keep passage 42 normally closed. This is to insure against the building up of excessive fluid pres.- sures on the right side of the piston head. If such undesired fluid pressures exist the ball 43 will be unseated against the action of spring 44 and fluid will flow from chamber 30 through passages .42, 39 and 40 into chamber 22. Such a condition might arise in the event the poppet valve 36 should stick in its closed position after the engine has fired.

I claim:

1. An hydraulic starter for engines comprising a housing, a rotatable drive shaft, a sleeve splined thereto for sliding movement thereon and for rotatable drive thereby, said sleeve having a piston head at its one end and a starter pinion at its other end for engaging an engine gear, an hydraulic motor for driving said shaft, a porting plate, a fluid inlet and outlet-port for said housing, said motor having an inlet and outlet port, said motor having an inlet port, means for imparting hydraulic driving power to said sleeve to extend it and said pinion to a predetermined extent While simultaneously imparting hydraulic driving power to said motor to rotate said shaft relatively slowly and upon further extension of said pinion into mesh with the gear to be driven thereby to rotate said shaft and pinion at a relatively greater speed, said means comprising spring means for normally retracting said starter pinion, an annular chamber surrounding said sleeve, a spring in said chamber for normally retracting said pinion and maintaining a restricted communication between said inlet port and said annular chamber, a restricted chamber on the opposite side of said piston from said spring and a restricted communication between said annular chamber and said restricted chamber, for metering the fluid flow from the inlet port to the restricted chamber until said piston is forced past said inlet, at which time full fluid flow is obtainedfrom said inlet motor.

2. An hydraulic starter for engines comprising a housing, a rotatable drive shaft, a sleeve splined' ton head at its one end and a starter pinion at its other end for engaging an engine gear, an hydrau lic motor for driving said shaft, a porting plate, a

fluid inlet and outlet" port for said housing, said motor having an inlet and outlet port, said motor having an inlet port, means for imparting hydraulic driving power to said sleeve to extend it and said pinion to a predetermined extent while simultaneously imparting hydraulic driving power to said motor to rotate said shaft relatively slowly and upon further extension of said pinion into mesh with the gear to be driven thereby to rotate said shaft and pinion at a relatively greater speed. said means comprising spring means for normally retracting said starter pinion, an annular chamber surrounding said sleeve, a spring in said chamber for normally retracting said pinion and maintaining a restricted communication between said inlet port and said annular chamber, a restricted chamber on the opposite side of said piston from said spring and a restricted communication between said annular chamber and said restricted chamber, for metering the fluid flow from the inlet port to the restricted chamber until said piston is forced past said inlet, at which time full fluid flow is obtained from said inlet to said motor, a second passage between said annular chamber and the opposite side of said piston and a poppet valve in said passage, a spring to urge said poppet valve open,said poppetvalve being held closed by abutment with said porting plate under urging of said sleeve spring and also under high fluid pressure on said piston head in the extension stroke of the starter pinion for the purpose of allowing fluid trapped in said annular passage to escape to said motor to permit said sleeve to return quickly to retracted position under the urging of said sleeve spring to retract and maintain said starter pinion out of mesh with said engine gear after said engine has been started.

3. An hydraulic starter for engines comprising a housing, a rotatable drive shaft, a sleeve splined thereto for sliding movement thereon and for rotatable drive thereby, said sleeve having a piston head at its one end and a starter pinion at its other end for engaging an engine gear, an hydraulic motor for driving said shaft, a porting plate, a fluid inlet and outlet port for said housing, said motor having an inlet and outlet port. said motor having an inlet port, means for imparting hydraulic driving power to said sleeve to extend it and said pinion to a predetermined extent while simultaneously imparting hydraulic driving power to said motor to rotate said shaft relatively slowly and upon further extension of said pinion into mesh with the gear to be driven thereby to rotate said shaft and pinion at a relatively greater speed, said means comprising spring means for normally retracting said starter pinion, an annular chamber surrounding said sleeve, a spring in said chamber for normally retracting said pinion and maintaining a restricted communication between said inlet port and said annular chamber, a restricted chamber on the opposite side of said piston from said spring and a restricted communication between said annular chamber and said restricted chamber, for metering the fluid flow from the inlet port to the restricted chamber until said piston is forced past said inlet, at which time full fluid flow is obtained from said inlet to said motor, a second passage between said annular chamber and the opposite side of said piston and a poppet valve in said passage, a spring to urge said poppet valve open, said poppet valve being held closed by abutment with said porting plate under urging of said sleeve spring and also under high fluid pressure on said piston head in the extension stroke of the starter pinion for the purpose of allowing fluid trapped in said annular passage to escape to said motor to permit said sleeve to return quickly to retracted position under the urging of said sleeve spring to retract and maintain said starter pinion out of mesh with said engine gear after said engine has been started, a third passage between said annular chamber and the opposite side of said piston and a check valve in said passage, a spring to urge said check valve away from said annular chamber to closed position and adapted to be opened against the action of its spring upon building up of excess pressure on said piston head in the event of mulfunctioning of said poppet valve in closed position to insure escape of fluid trapped in said annular chamber to said motor.

ALBERT C. JENNY.

REFERENCES CITED UNITED STATES PATENTS Name Date Molyneux et al. Feb. 28, 1950 Number

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