US2468019A - Internal-combustion device - Google Patents

Description

April 26, 1949. F. N. BARD 2,468,019

INTERNAL-COMBUSTION n'nvicz Filed larch 2a, 1946 4 Sheets-Sheet 1 April 26, 1949. F. N. BARD 2,468,019

INTERNAL-COIBUSTION DEVICE Filed larch 28, 1946 7 w jwzzj aw 4 Sheets-Sheet 2 April 26, 1949. F. N. BARD 2,468,019

INTERNAL-CmlBUSTION DEVICE Filed March 28, 19.46 4 Sheets-Sheet 3 April 26, 1949.- F; N. BARD 2,463,019

' I INTERNAL-"COMBUSTION DEVICE Filed larch .28, 1946 4 Sheets-Sheet 4 fia/zczf M 1 Patented Apr. 26, 1949 UNITED STATES PATENT OFFICE Francis N. Bard, Highland Park, '11].

Application March 28, 1946, Serial No. 557,649

in such a hammer, it has heretofore been considered impossible to use a magneto for gen- 8 claims. (01. 123-149) crating the ignition spark. I have devised, and

- am here disclosing, magneto and ignition ar-,

rangements which are capable of operation by means other than a rotating crank shaft, which are properly timed and related to piston movement despite the absence of a crank shaft, and

which are sufliciently rugged in constructionv to withstand the vibration present in a hammer of the free piston type.

This application is one of two copending companion applications relating to magneto ignition of an internal combustionhammer; my other companion application being Serial No. 657,650, filed March 28, 1946.

Various features and advantages of this invention Will be apparent from the following specification and the drawings, in which:

Figure 1 is a side elevational view, partly in vertical section, of a free pistoninternal combustion hammer incorporating one embodiment of my inventions; Figure 2 is anenlarged vertical sectional view of the magneto and actuating this general type, but with battery ignition, have been made and sold for some years by my company, and the description of the general principles of such hammers and of their operation will be kept brief since reference may be made to issued patents to supplement the present disclosure if desired, as for example Mould Patents. 1,868,754 and 1,997,072 and Charles Patents 2,180,034 and 2,275,285, these being merely representative examples of the many issued patents on such hammers.

Briefly to describe the operation of the hammers here disclosed in Figures 1-5, gasoline in a tank I2 is mixed with air in carburetor l3 and delivered to the chamber [4 beneath the piston, where it is partly compressed by the downward stroke thereof. Near the bottom of the working strokeof the piston the charge is transferred from'this lower space to the combustion space assembly, along the line 2-2 of Figure 3;,Figure' 3 is an end view of the magneto with the cover removed, lookingfrom the left of Figure 2; Figure 4 is a horizontal sectional view along the line 4-4 of Figure 3; Figure 5 is a schematic view showing the ignition circuit; Figure 6 is a partial view of an internal combustion hammer incorporating another embodiment of my inventions; Figure 7' is a vertical sectional view along the line 7-1 of Figure 6, and Figure 8 is a transverse sectional view through the magneto, along the line 88 of Figure 6. I

The internal combustion percussive device with which I am here concerned is of a type providing a self-contained gasoline powered device for such purposes as pavement breaking, rock drilling, tamping, and the like. The cylinder I0 comprises the main body portion of the device and has a piston-hammer ll freely reciprocable therein, being driven downwardly by. the explosion of a combustible charge thereabove and being returned by the action of a return spring assisted by rebound. Hammers of above the piston, at the top of the cylinder In,

through transfer passages which preferably include, passageway portions inthe piston H and the portion I5 in the cylinder [0. The combustible charge thus provided in the upper end of the cylinderis then further compressed on the upward stroke of the piston, effected primarily by. the return spring I6, and at a proper time with respect to' piston movement this charge is ignited ,by causing a sparkto jump across the electrodes of the spark plug I1. Combustion of this charge drives the piston downward on its working stroke, the lower'end of the piston eventually striking the top of the anvil l8 in the anvil-housing l9 and the blow thus being transmitted to the tool .20. As the piston nears the lower endof its travel the burned gases are discharged through the exhaust port 2|, 2. fresh charge transferred to the space above the piston, and the cycle of operation repeated.

Handles 22 and 23 are provided to enable a workman to spot the tool in a desired working point, to maintain the hammer in operative position duringworking thereof, and to lift the hammer between operations. Starting is accomin a manner obviating the necessity for cables, storage batteries, and the like, comprises the improvement to which this and my companion application are directed, and these will now be more particularly described.

Referring now more particularly to Figures 2, 3 and 4, a magneto identified in general as A will be seen to bemounted on the side wall of the cylinder Hi, this magneto comprising as its principal parts an outer permanent magnet or pole assembly 26, a laterally movable armature member 21, and a coil 28 wound thereon, this coil comprising a primary and secondary in accordance with the practice followed in rotary magnetos of a more conventional type.

The movable armature and coil of the magneto are rigidly mounted on a rod-like member 29 mounted for longitudinal or axial movement, one end of this rod member 29 being mounted in the side wall of the cylinder ill for movement in a direction transverse to that of the piston II and being provided with a roller 30 in engagement with the side wall of thepiston at all times during its movement, the piston being shown at the uppermost limit of its movement in Figures 1 and 2. The piston is provided on its side wall with a cam groove Ha having a shouldered portion Ha so that the roller 30 and rod member 29 are moved outwardly. of the cylinder (i. e., to the left as viewed in Figure 2) at the properly timed instant when a spark is to be generated at the spark plug, analogous to the breaker point actuating arrangement shown in Mould Patent 1,868,754 mentioned heretofore.

The other or outer end of the rod member 29 is'mounted' in suitable bearings in the block 3|, being constantly biased inwardly (to the right as viewed in Figure 2) by the spring 32. The outer end of the rod member 29 carries an adjustable stud 29a bearing against a spring metal member a 33 fixedly mounted at one end (the right hand end as viewed in Figure 3) and carrying a movable breaker point 34a adapted to cooperate with a fixedly (though adjustably) mounted breaker point 341). The whole assembly is enclosed by a cover 35 having a high tension cable .36-leading therefrom to the central or hot electrode of the spark plug.

When the piston is in the central and lower portions of its range of movement, the roller 30 would lie in the groove Na in the piston wall and the armature member 21 would be to the right of the position shown in Figure 2, in good magnetic relationship to the pole segments 26a and 26b and spaced from the pole segments 26c and 26d. The outer pole structure would include permanent magnetic material, as Alnico, and the arrangement might be such that the pole segment 26a is north and the pole segment 26b south while the pole segment 260 is south and the pole segment 26d north. With the armature at the innermost limit of its movement toward the cylinder wall, the upper end would have a north magnetic polarity and its lower end would have a south magnetic polarity, whereas if the armature is shifted to the position shown in Figure 2 by movement of the roller 30 up the cam shoulder Ha on the piston, the upper end of the armature would be south and thelower end north, thus resulting in a complete reversal of magnetic, flux conditions through the winding 28. At an appropriately timed instant when the current in thep'rimar'y 28a of the winding (referring now more'p'articul'arly to Figure 5) is at or near its maximum, the movement of the rod member 29 would bring the stud 2941 into engagement with the spring member 33, and cause separation of the breaker points 34, resulting in a complete collapse of the magnetic field around the primary and the generation of a very high voltage (of the order of 10,000 volts) impulse in the secondary 281) which would be delivered to the spark plug I! through the cable 36 and cause sparking at the plug electrodes, with attendant ignition of the combustible charge in the cylinder. In order to minimize arcing at the breaker points, a condenser 36 is utilized in conventionalinanner in shunt with such points; and the return connections of the circuit are made through a ground. in this case the frame or main body structure of the hammer. The entire assembly for the first time provides a satisfactory and usable ignition system for an internal combustion hammer of the free piston type, satisfactorily operable without a crank shaft and capable of withstanding the tremendous vibrationpresent in such a hammer, obviating the necessity for storage batteries and cables to provide ignition as has heretofore been customarily the case.

Another embodiment of my inventions for magneto ignition of an internal combustion hamber of the free piston type is illustrated in Figures 6, 7 and 8. In order to keep the description of this modification as brief as possible, reference numerals higher than those heretofore used will be applied to parts analogous to those described in connection with Figures 1-5, so that reference back to the earlier portions of the specification may be made if desired.

The hammer again comprises as its principal body portion a cylinder having a piston 6| freely reciprocable therein, a combustible charge being ignited above this piston at an appropriate time by ignition means such as a spark plug 81 to drive the piston downward, return being by a return spring and rebound. In this case the magneto, indicated in general asB, is of the type with a rotatable or oscillatable rotor or armature 11 carrying primary and secondary windings 18a and 18b anddisposed in operative relation to an.

outer pole structure 16. The pole relationships are again such that movement of the armature 11 (in this case oscillation back and forth through a rather limited range of the order of 15) is sufficient to create the desired primary current which is broken at an appropriate instant by suitable breaker points to provide the high tension output from the secondary 18b.

In this case the actuating means for the movable parts of the magneto again comprises a member movably mounted in the side wall of the cylinder 60, as the member 19, but in this case the member is rotatably mounted therein. The inner end of the member 19 isprovided with an extending crank arm portion 19b carrying the roller 80,*the roller in this case bearing against the side wall of a slot cut in the side ofthe piston II, as the side wall Ha of such slot. The rod member 19 is normally rotatably' biased by the spring 88 in a direction tending to keep the roller always in engagement with the groove wall during movement of the piston; and at the appropriate time with relation to piston movement, the roller 80 moves down into the depressed portion Ila. to effect a sudden fairly rapid partial rotation of the armature or.rotor member 11 resulting in generation of a spark at the electrodes of the spark plug 61. If the spark thus produced fails to fire the combustible chargefor any reason further upward movement of the piston causes the roller to drop into the second depressed portion lla", resulting in a second spark, the plurality of sparking operations improving the certainty of ignition. The concept of using the side of a groove cut into the wall of a piston is more fully disclosed and claimed in the copending Breitenstein and Ingebretsen application Serial No. 593,386, filed May 12, 1945, now Patent No. 2,442,284, although there was heretofore no concept of such an arrangement operating anything more than the breaker point.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:-

1. An internal combustion device of the freepistontype, including: a cylinder adapted to have a combustible charge therein; a piston freely reciprocable therein; electrical ignition means in one end of the cylinder; a magneto for generating a spark at said ignition means; and actuating means including means in engagement with said piston at all times during its reciprocation for actuating the magneto by and in accordance with an actuating arrangement including a follower member in engagement with said piston at all times during itsreciprocation for actuating the magneto by and in accordance with movement of said piston for efiecting generation of the spark when the piston approaches said end of the cyl-' inder.

3. An internal combustion device of the free-' piston type, including 'a cylinder adapted to have a combustible charge therein; a piston freely reciprocable therein; electrical ignition means in one end of the cylinder; a magneto for generating a spark at said ignition means; and actuating means for the magneto including a member movably mounted in a side wall of said cylinder and having means at one end in engagement with the free-piston type, including: a cylinder adapted to have a combustible charge therein; a piston freely reciprocable therein;.a tool adapted to have impacts transmitted thereto upon reciprocation of said piston; electrical ignition means in one end of the cylinder; a magneto for generating a generation of the spark when the piston ap longitudinally movable in a side wall of said cylinder and having a roller means at-one end in engagement with said piston at all times during its reciprocation for actuating the magneto by and in accordance with movement of said piston for effecting generation of ,the' spark when the piston approaches said end of the cylinder.

6. An internal combustion percussive device of the free-piston type, including: a cylinder adapted to have a combustible charge therein; a piston freely reciprocable therein; a tool adapted to have impacts transmitted'thereto upon reciprocation of said piston; electrical ignition means in one end of the cylinder; a magneto for generating a spark at said ignition means, this magneto having an oscillatable armature and at least one movable breaker point; and an actuating arrangement for oscillating the armature and moving the breaker point including a member rotatably movable in a side wall of said cylinder and having a roller at one end in engagement with said piston at all times during its reciprocation for actuating the magneto by and in accordance with movement of said piston, the portion of the piston engaged by.the roller having a plurality of similar variations near one end such that a plurality of sparks are generated when the piston approaches said end of the cylinder.

7. An internal combustion percussive device of the free-piston type, including: a cylinder adapted to have a combustible charge therein; a piston freely reciprocable therein; a tool adapted to have impacts transmitted thereto upon reciprocation of said piston; electrical ignition means in one end of the cylinder; a magneto for generating a spark at said ignition means, this magneto having a rotatably movable armature and at least one movable breaker point; and actuating means for moving the armature and breaker point including a member rotatably mounted in a side wall of said cylinder and having a roller means atone end in engagement with said piston at all times during. its reciprocation for actuating the magneto by and in accordance with movement of said piston for effecting generation of the spark when the piston approaches said end of the cylinder 8. An internal combustion percussive device of the free-piston type, including: a cylinder adapted to have a combustible charge therein; a piston freely reciprocable therein; a tool adapted to have impacts transmitted thereto upon reciprocation of said piston; electrical ignition means in one end of the cylinder; a magneto for generating a spark at said ignition means, this magneto having a rotatably movable armature and at least spark at. said ignition means; and actuating means for the magneto including a member movably mounted in a side wall of said cylinder and having a roller means at one-end in engagement with said piston at all times during its reciprocation for actuating the magneto by and in accordance with movement of said piston for. efiecting one movable breaker point; and an actuating arrangement for moving the armature and breaker point including a member rotatably mounted in a side wall of said cylinder and having a roller at one end in engagement with said piston at all times during its reciprocation for actuating the magneto by and in accordance with movement of said piston, the portion of the piston engaged by of the cylinder.

7 the roller having a plurality of similar variations near one end such that a plurality of sparks are generated when the piston approaches saidend FRANCIS N. BARD.

REFEBENQES amen Thefollowing references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Bain Dec. 28, 1886 Van Deventer Oct. 23, 191'? Trapnell Nov. 1, 1927 Fitch Nov. 2, 19433

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