US3250265A - Model engine starter - Google Patents

Description

May 10, 1966 J. M. BARR MODEL ENGINE STARTER 2 Sheets-Sheet 1 Original Filed Aug. 25, 1961 HIHHHIHHI" INVENTOR JOSIAH MORRISON BARR ATTORNEY y 10, 1966 J. M. BARR 3,250,265

MODEL ENGINE STARTER Original Filed Aug. 25. 1961 2 Sheets-Sheet 2 IIHHHHHWIHH INVENTOR. @l-f/fl/V Maze/$0M 642/2 United States Patent Original application Aug. 25, 1961, Ser. No. 134,540. Divided and this application June 23, 1965, Ser. No.

Claims. (Cl. 123-179) This application is a divisional application of my earlier application Serial No. 134,540, filed on August 25, 1961, now abandoned, which, in turn is a continuation-inpart application of my prior application Ser. No. 57,722, filed September 22, 1960, now abandoned, having the same title.

This invention relates to starting devices for toy engines employed to drive toys such as airplanes wherein the engine is ordinarily started by spinning the propeller in the reverse direction to its normal rotation for winding a spring starter.

Various spring starting devices have been developed for this type of engine. For example, the starter shown in US. Patent 2,855,070, of I. W. McRoskey et al., October 7, 1958, has worked well. However, it has been somewhat difiicult to replace the starting spring if that should become broken. Another simplified form of starter is shown in U.S. Patent 2,751,898, of P. M. De Groat, June 26, 1956. This structure, while of simple design, has had a number of disadvantages, such as its failure to disengage from the propeller and lack of support for the spring when it is wound, so that the spring can be readily damaged.

It is an object of my present invention to provide a simplified starting structure which will be easy and economical to manufacture and which will be reliable in operation, and in which the starting spring is provided with proper support when it is fully wound.

Another object of my invention is to provide a simplified spring starter which employs an over-running clutch to engage and disengage the power driven drive shaft with the starting spring.

A further object of my invention is to provide a model engine starter which employs a starting spring which is not only simple to construct, but which may be readily replaced in the event the starting spring becomes broken.

A further object of my invention is to provide a starting spring mounted on the engine block and completely exposed for inspection in a model engine starter wherein a clutch is associated with the drive shaft to engage the free end of the spring when starting the engine and to disengage the free end of the spring immediately upon starting of the motor.

Another object of my invention is to provide an improved and simplified clutch for model engine starters which will be of simple design and economical to construct as well as reliable in operation.

Other objects and features of the invention will appear as the description of the particular embodiment selected to illustrate the invention progresses. In the accompanying drawings, which form a part of this specification, like characters of reference have been applied to corresponding parts throughout the several views which make up the'drawings.

FIG. 1 is a side view of the engine block and starter associated therewith.

FIG. 2 is a plan, or end, view of the clutch.

FIG. 3 is a side view of the starter similar to that illustrated in FIGS. 1 and 2, except that in FIG. 3 one end of the starter spring is connected to the shaft, while in FIG. 1 the same end is connected to the engine block.

FIG. 4 is a transverse sectional view of a clutch plate frame and shaft taken along line 44 shown in FIG. 3.

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FIG. 5 is an enlarged side view partly in section, of an alternative spring connection for FIG. 3.

Referring to the drawings, the engine housing 10 has a rotary shaft 12 extending outwardly from the crank case 14. A cam surface 16 is fixedly mounted on the serrations 18 formed on the crank shaft 12 which prevents the cam 16 from rotating about the shaft 12.

A hub 22 is also fixedly mounted on the drive shaft 12. A propeller 24 is squeezed against the hub 22 by means of a rounded headed nut 26 which is threaded on the threaded end portion 28 of the driven shaft'12.

The automatic starter I have referred to consists of a coil spring 28 which has a hook 30 formed on one end which is hooked on a suitable stationary portion of the motor such as a mounting lug 32. The coils of the spring 28 are spirally wound loosely and at a distance spaced from the crank case 14. The free end 34 of the spring 28 extends into the rotary path of travel of the drive pin 36. The drive pin 36 is formed with a pressed fit in the clutch housing 38 and extends from the same in the path of travel of the spring 34.

Two or more suitable cylindrical discs 40 are interposed between the cam surface 42 of clutch housing 38 and the cam surface 44 of the cam 16.

The cam surfaces have such a configuration that when the cam 16 is rotated in one direction, it causes the cam surface 42 and 44 to move together which in turn causes the discs 4% to be gripped between these two cam surfaces. In this way, when the cam 16 is rotated in one direction the cam face 42 of clutch housing 38 is gripped thereby rotating the clutch housing 38. The spiral spring 28 is wound in the direction which causes the pin 36 carried by the gripped clutch housing 38 to engage with the free end 34 of spring 28, thereby causing the spring 28 to be wound up.

When the cam 38 is rotated in this manner, it causes the .end of the spring 34 to be engaged by the pin 36 and thereby wound up. This is accomplished by turning the prop 24 in a clockwise direction with respect to the arrangement used in the drawing for illustrating the invention. When the spring 28 has been wound up in the manner indicated, the prop 24 can then be released, which will cause the spring end 34, engaging with the pin 36, to rotate the clutch housing 38 in their reverse directions because of the stored up spring energy.

The clutch housing 38 having been previously moved relative to cam 16 is still gripping the cam surface 44 by means of the jamming action effected on the discs 40.-

When the spring 34 has rotated shaft 12 and expended its energy, and ceases to positively rotate the shaft 12, it will have imparted a sufiicient speed of rotation to the cam 16 and thereby to the shaft 12, so that the engine will have become started.

Because of the inertia and momentum of shaft 12 and the driving force imparted thereto from the engine, it will cause the cam surfaces 44 and 42 to move in a direction which will cause the distance between same to be increased, thereby disengaging discs 40 and allowing the cam 16, fixedly mounted on shaft 12, to freely rotate out of engagement with the clutch housing 38. The clutch housing 38 therefore rides freely on the shaft 12 and the hub 22.

The discs 40 are confined in the space formed between the retainer plate 20 and the back portion 39 of the clutch housing, 38. The retaining plate 20 is held in place by the bent over flanges 46.

From the foregoing description it will be apparent that should the starting spring 28 become broken, one would merely have to remove the nut 26 and the prop 24 to permit the spring 28 to be replaced. Replacement would be etfected by spiralling one turn of the spring at a time 3 over the clutch housing 38. If -it should be desired to further facilitate the replacement of the starting spring without the necessity of spiralling one turn at a time over the clutch housing 38, this could be done by simply removing thehub 22 and the cam 16 which constitutes part of the assembly of the clutch housing 38. When this is done, the old spring 28 can be removed and the new spring pushed in place.

No special tools, nor any great degree of mechanical skill is required to effect a replacement of the starting spring in this manner. While the spring starter I have disclosed is of a simple design, it nevertheless does its task very efficiently without becoming jammed and without causing any damage to propellers.

While I have shown the over-running clutch mounted between the propeller shaft and the free end of the spring, it will be apparent my simplified clutch is of such a design that it could also be mounted on the motor block housing with the starting spring located between the clutch and the propeller shaft without departing from the scope of my invention.

This additional version of the starter is illustrated in FIGS. 3 to 5 where the same elements have the same numerals as in FIGS. 1 and 2. As stated above, the main difference resides in the fact that the outer end 28a of spring 28, which corresponds to the end 30 of the spring 28 in FIG. 1, is now connected to washer 22, which is mounted on the serrated portion 18 of shaft 12 in the same manner as it is mounted in FIG. 1. In this version of the invention, however, washer 22 is made of a larger diameter so as to receive the outer end 28:: of spring 28. In this case, washer 22 is provided with a hole 300 for receiving end 28a of spring 28. It may be more convenient and practicable from a production point of view to provide spring 28 with a hook 28b and provide washer 22 with a pin 302 for connecting spring 28 to washer 22. (See FIG. 5). Otherwise, when spring 28 is wound, end 28a may slip out of hole 300 unless a very tight engagement is obtained between the end 28a and washer 22. A simpler solution of this problem from the manufacturing standpoint is that illustrated in FIG. 5. This is the type of connection which is illustrated in FIG. 1 by pin 36 and hook 34, the same connection also being illustrated in FIG. 3 by the same pin 36 and hook 34 which interconnects the other end of the spring with the clutch plate 38. This plate is identical in every respect to plate 38 in FIG. 1, except that it is turned 180 in its position with respect to block of the engine. The cam plate 16 now is mounted on the extension, or crank case 14, which is an extension of the engine block 10 while in FIG. 1, this cam plate 16 is mounted on the serrated portion 18 of shaft 12. The two clutch discs 48 are also used in FIG. 3 which interconnects the cam plate 16 with the clutch plate 38 in the manner described previously in connection with the description of FIGS. 1 and 2. Retaining ring 20 is also used for retaining discs 40 in the grooves 44, FIG. 2, provided in the cam plate for accommodating discs 40. This retaining ring is held in tight, fixed engagement with respect to the clutch plate 38 by means of bent-over edges 46 of the clutch plate in the same manner as in FIG. 1.

From the description given previously of FIGS. 1 and 2, it follows that in the arrangement illustrated in FIG. 3, spring 28, from a functional point of view, is always rigidly connected to shaft 12, and therefore, rotates with shaft 12 under all circumstances. This also means that the following elements always rotate with the shaft: washer 22, spring 28, clutch plate 38, pin 36 and retaining ring 28. When all of the above elements rotate with shaft 12, and when engine is running, there is nolocking connection between clutch plate 38 and cam plate 16 because the clutch plate 38 is rotating in a clockwise direction with respect to cam plate 16 as viewed in FIG. 4. At this time, the discs 40 are in the position illustrated in solid lines in FIG. 4 and, therefore,

as described previously, the cam plate 16 and the clutch plate 38 are not interlocked and, therefore, are free to rotate with respect to each other.

In order to start the engine, propeller 24 is rotated in a clockwise direction when viewed from the direction indicated by arrow 310. Rotation of propeller 24 in a clockwise direction produces a counter-clockwise rotation of clutch plate 38, as viewed in FIG. 4 which corresponds to the rotation of cam plate 16 in the opposite direction. At this instant, discs 40 become immediately wedged between the cam plate 16 and the clutch plate 38 as shown by'the dot-dash lines 49 of FIG. 4 and in the same manner described previously, and therefore, the cam and clutch plate become rigidly inter-connected with respect to each other. This also rigidly connects end 34 of spring 28 to block 10 of the engine, and therefore, clockwise rotation of the propeller 24, as viewed in the direction of arrow 318, winds the spring until it becomes tightly wrapper around the crank case 14 which comprises the extension of the engine block 10. When the spring becomes tightly wound around crank case 14, it cannot be wound any further and this comprises a positive stop point at which the propeller cannot be wound any further in the clockwise direction.

The propeller is then released and the energy stored in the spring turns shaft 12 now in its normal counterclockwise direction, thus starting the engine.

From the description of FIG. 3, it follows that the functioning of the starter in FIG. 3 is identical to that illustrated in FIG. 1, except that, in this case, clutch plate 38 remains stationary because it is mounted on frame 10 of the engine, while in FIG. 1 it is fixed to shaft 12.

It is preferable to have the arrangement illustrated in FIG. 1 because the number of elements which rotate when the engine is operating in normal manner, i.e., under its own power, is reduced to an absolute minimum in FIG. 1. Only cam plate 16 and two discs 40 rotate with the engine in FIG. 1, when it is operating under its own power. In FIG. 3, on the other hand, when the engine operates under its own power, all of the elements of the starter rotate and only cam plate 16 and discs 40 are stationary. This means that washer 22, spring 28, clutch plate 38, pin 36 and spring hooks 34 and 28a, all rotate as a single element when the engine operates under normal conditions.

The invention hereinabove described may therefore be varied in construction within the scope of the claims, for the particular device selected to illustrate the invention is but one of many possible embodiments of the same. The invention, therefore, is not to be restricted to the precise details of the structure shown and described.

The invention and its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts of the inven tion without departing from the spirit and scope thereof or sacrificing its material advantages, the arrangement hereinbefore described being merely by Way of example and we do not wish to be restricted to the specific form shown or uses mentioned except as defined in the accompanying claims, wherein various portions have been separated for clarity of reading and not for emphasis.

I claim:

1. A starter for a model internal combustion engine comprising:

(a) an engine block;

(b) an engine shaft extending outwardly from said engine block;

(0) an engine starting 'coil spring .spirally wound around said shaft;

(d) means for connecting said spring with one end to said shaft and with the other end to said engine block during the starting cycle of said starter, said means including (e) a clutch plate connected to one end-of said spring;

(f) a cam fixed to said engine shaft and concentrically disposed with respect to and within said clutch plate; and

(g) clutch plate locking means for locking said plate to said cam when said plate is rotated with respect to said cam in the direction opposite to the normal direction of rotation of said shaft, rigidly connecting said spring between said shaft and said block for producing the winding of said spring, with one end of the spring being held in fixed position by said engine block and the other end of said spring being held in fixed position with respect to said shaft during said winding operation, whereby said spring becomes wound between said block and said shaft when said shaft is rotated in the reverse direction, opposite to the normal direction of rotation of said shaft by said engine, said clutch plate locking means holding said cam and said clutch plate locked with respect to each other as long as said spring turns said engine in the normal direction during the un winding and the engine-starting cycle of said spring and releasing said clutch plate from said cam upon the completion of the unwinding cycle of said spring.

2. A starter for a model internal combustion engine having (a) an engine block including ('b) a hollow right cylinder projecting beyond and being an integral part of said cylinder block, said cylinder having an inner end and an outer end, said inner end being adjacent to said engine block;

(0) a cam plate fixedly mounted on the inner end of said cylinder;

(d) a clutch plate rotatably mounted on said cylinder;

(e) means for rigidly interconnecting said clutch plate with said cam plate when said clutch plate is rotated in one direction and for releasing said clutch plate from said cam plate when said clutch plate is rotated in the opposite direction;

(-f) an engine starting coil spring surrounding said cylinder, said coil spring having an inner end and an outer end, the inner end of said spring being connected to said clutch plate;

(g) a crank shaft for said engine said crank shaft having an external shaft extending beyond said engine block and passing through and, with its outer end, beyond said hollow cylinder;

(h) a washer rigidly mounted on the outer end of said shaft; and

(i) a connection between said washer and the outer end of said spring, said engine starting spring being wound tightly against the outer surface of said cylinder when said shaft is turned in the direction opposite to the normal rotation of said shaft because of the interlocking by said means between said cam and clutch plates, said means continuing said rigid interlocking until said spring becomes fully unwound upon the release of the shaft end of the spring after the completion of the winding operation, said clutch plate and said cam becoming unlocked from each other upon the completion of the unwinding cycle said cam to cause said clutch plate to lock with said cam when said clutch plate and said cam are rotated vw'th respect to each other in one direction and to cause said clutch plate and said cam to rotate in the opposite direction independently of each other after said means unlocks said plate from said cam; and

(g) a spring interposed between said engine block and said clutch plate, one end of said spring being fixed to said engine block and the other end having means for engaging said clutch plate to cause the fixed cam to be positively rotated by the energy stored in said spring until said spring is unwound, said spring being wound when the fixed cam is rotated in the direction opposite to that in which the shaft is driven by the combustion engine, said spring being the only spring in said starter.

4. A starter for a model internal combustion engine having:

(a) an engine block and (b) a piston operated crank shaft extending therefrom;

(c) a starting coil spring helically wound around and extending along the axis of rotation of said shaft; (d) mechanism for hooking one end of said coil spring to a stationary part of said engine block;

(e) a clutch having a cam plate fixed to the drive shaft and having a clutch plate mounted to engage with the opposite end of said coil spring; and

(f) means positioned between said camplate and said clutch plate to cause said cam plate and said clutch plate to rotate together to wind up the spring when said cam plate is rotated in one direction and for allowing said cam plate to freely rotate independently of said clutch plate after unwinding of said spring.

5. A starter for a model internal combustion engine having:

(a) an engine block element and (b) a piston operated crank shaft element extending therefrom;

(c) a starting coil spring wound about said shaft element;

(d) mechanism for securing one end of said coil spring to one of said elements;

(e) a clutch having a cam plate fixed to the other one of said elements, and having a clutch plate mounted to engage with the opposite end of said coil spring; and

(f) means positioned between said cam plate and said clutch plate to cause said cam plate and said clutch plate to rotate together to wind up the spring when said cam plate is rotated in one direction, and for allowing said cam plate to freely rotate independently of said clutch plate after unwinding of said spring.

References Cited by the Examiner UNITED STATES PATENTS of said spring. 1,220,692 3/1917 Schulte 123- 1 79 3. A model internal combustion engine having: 2,751,898 8/1954 De Groa-t 18537 X (a) an engine block and 2,855,070 10/ 1958 McRoskey et a1 185-37 (b) a piston operated crank shaft extending there- 3,131,682 5/ 1964 Garofalo 123179 from; and 3,159,154 12/ 1964 Garof-a-lo 123-179 (0) a starter for said engine, said starter, including (d) a cam fixedly mounted on said crank shaft; (e) a clutch plate;

(f) means interposed between said clutch plate and MARK NEWMAN, Primary Examiner.

LAURENCE M. GOODRIDGE, Examiner.

Claims (1)

1. A STARTER FOR A MODEL INTERNAL COMBUSTION ENGINE COMPRISING: (A) AN ENGINE BLOCK; (B) AN ENGINE SHAFT EXTENDING OUTWARDLY FROM SAID ENGINE BLOCK; (C) AN ENGINE STARTING COIL SPRING SPIRALLY WOUND AROUND SAID SHAFT; (D) MEANS FOR CONNECTING SAID SPRING WITH ONE END TO SAID SHAFT AND WITH THE OTHER END TO SAID ENGINE BLOCK DURING THE STARTING CYCLE OF SAID STARTER, SAID MEANS INCLUDING (E) A CLUTCH PLATE CONNECTED TO ONE END OF SAID SPRING, (F) A CAM FIXED TO SAID ENGINE SHAFT AND CONCENTRICALLY DISPOSED WITH RESPECT TO AND WITHIN SAID CLUTCH PLATE; AND (G) CLUTCH PLATE LOCKING MEANS FOR LOCKING SAID PLATE TO SAID CAM WHEN SAID PLATE IS ROTATED WITH RESPECT TO SAID CAM IN THE DIRECTION OPPOSITE TO THE NORMAL DIRECTION OF ROTATION OF SAID SHAFT, RIGIDLY CONNECTING

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