US2561093A - Internal-combustion rammer - Google Patents

Description

INTERNAL-COMBUSTION RAMMER Filed June 7, 1947 3 Sheets-Sheet 1 July 17, 1951 v. w. BREITENSTEIN EI'AL INTERNAL-COMBUSTION RAMMER Filed June 7, 1947 3 Sheets-Sheet 2 a very much heavier rammer.

Patented July 17 1951 INTERNAL-COMBUSTION HAMMER Victor W. Breitenstein, Chicago, and Emmons R.

Boddinghouse, Evanston,

Francis N. Bard Ill. :assignors to Application June 7, 1947, Serial N0.7 53,2'70

.3 Claims.

This invention relates to -a rammer, and more particularly to a ramming or tamping device of the so-called leaping type, operated by internal combustion.

While small hammers are sometimes used for tamping, heavy tamping or-ramming, as for example in back fill work, is preferably done with The basic principles of rammers of the "leaping" type have heretofore been known, but certain defects have been present and such rammers have not gone into commercial use in this country. Rammers of the type with which we are here concerned comprise a relatively heavy generally vertical bodywhich would normally weigh in the neighborhood of 200 pounds, and which leaps into the air as the result of an internal explosion of ,a combustible mixture (as a gasoline-air mixture) under the control of an operator, to come down with its full weight and deliver a very efiective ramming blow.

"We have overcome previous defects and disadvantages of such rammers. One feature of the invention here being disclosed is in the provision of a satisfactorily operative combustion chamber relief valve enabling the lower piston (and the connected foot) to return rapidly to normal position, ready for the ramming blow,

at or near the top of the leap. Another feature of this invention is the provision of protecting arrangements for the intake and relief valves, particularly a protective arrangement for the air intake valve of the carburetor, obviating warpage, sticking and other difiiculties heretofore encountered-with such valves. Another feature of the device here being disclosed is the provision of an improved gasoline feed arrangement enabling gravity feed of gasoline to the carburetor while at the same time maintaining sufficient cooling between the gasoline tank and the combustion cylinder to prevent boiling of the gasoline. Yet a further feature of this invention is the provision of an air intake minimizing difficulties with dirt getting into the operative parts of the rammer. Other features and advantages will be apparent from the following specification and the drawing, in which:

Fi ure 1 is a view, principally in side elevation, of one embodiment of our invention; Figure 2 is a view, principally in vertical section along the .line 2-2 of Figure 1; Figure 3 is an enlarged fragmentary detail vertical sectional view of the upper portion of the device; 'Figure 4 is an enlarged fragmentary vertical sectional view of the combustion chamber and the valves associated .2 therewith; and Figure 5 is a fragmentary vertical sectional view of the carburetor along the line 5-5 of Figure 4.

Inasmuch as rammers of this general type have been the subject of a number of earlier patents and their general principles of operation are well known, the general construction and operation of the rammer will be only briefly described.

The device comprises four principal portions which may be termed the upper'or head portion, here identified in general as A; a central body portion E, including the combustion chamber; ;a lower body portion C; and afoot portion D. The upper, central and lower body portions are here shown as held together by tie rods 10 and H;

and the foot portion, together with the rod and rocate with respect to the body portion.

If the rammer be assumed to be standing on the ground as illustrated in Figures -1 and 2, a rammingleap is effectedby the operator' by-pushing down on the handle 12 and *then -releas-ing the same to effect an explosion and leap, the operator continuing to hold onto the handle I2 While the rammer is in the air in orderto'keep it under control, and repeating the leaps as frequently as he may desire by operation on the handle. Pushing down on the handle 12 onerates through the crossbar l3, overcoming the force of two springs (not shown but contained within the head -A to balance out the weight :of the handle, upper piston and interconnecting parts, and to normally keep these in uppermost position) to move therod l6 downwardly. This moves the valve H in the upper piston l8 away from its seat, and then pushes the piston l8 downwardly, gases remaining in the cylinder from the previous explosion-passing through the central opening Na in the upper piston during its downward movement. When the upper piston has reached the limit of .its downward movement (with its head substantially opposite the top of the inlet opening 19a in the cylinder 1-9) the'handle i2 would be moved upwardly. This closes the valve i'l onto its seat and lifts the piston 18 up, creating a vacuum in .the combustion chamber drawing in an air-gasoline mixture from the carburetor identified in general'as 29,'burned gases formerly-in the cylinderandnow above the upper piston I8 being exhausted to =ber 2-2 with which it cooperates) engages the shoulder 22a of the magneto operating member and moves it upwardly, rotating the shaft of the magneto, until it finally slips off of such shoulder at almost the top of its movement. Rotation of the magneto rotor is then efiected by a spring (not shown) and a spark is delivered to the plug 23 and jumps the points thereof to ignite the mixture.

Since the upper piston 18 is at the upper limit of its travel by this time, and the valve I! is closed, the expansion due to combustion in the cylinder i9 tends to separate the lower piston 24 and the upper piston l8. Inasmuch as this lower piston 24 is rigidly connected to the rod 25, in turn rigidly connected to the foot 26, and this foot is standing on the ground, there can be practically no downward movement of the piston 24. Instead, the force of the explosion causes the upper piston 18 and the whole body of the rammer to move upwardly into the air, the piston 24 thus moving downwardly in the cylinder l9 during this relative movement between the piston and cylinder. When the relative movement has caused the top of the piston 24 to be below the exhaust ports 21a and 211) the burned gases in the combustion chamber are exhausted and the spring 28 tends to return the piston 24 and foot 26 to a position relative to the body it) as shown in Figures 1 and 2. Since the body of the rammer is at this time normally a foot and a half to two feet in the air, the foot lifts up (raised by the spring 28) to return to its normal position with respect to its body, and then the entire device falls back to rest on the ground to deliver a heavy ramming blow.

One of the defects heretofore found in machines of this character has been in connection with the relative movement of the lower piston and body, and particularly the speed of return again reducing the force of the ramming impact.

We have overcome this defect by provision of a supplementary exhaust arrangement, higher up in the cylinder, which is closed during the explosion and downward movement of the piston 24, but open during the upward or return move- 1 ment thereof; and which is not open to the cylinder at the instant of explosion of the charge.

Referring now more particularly to Figure 4, it will be seen that the wall of the cylinder I9 is provided with a port 3| only slightly below the sealing rings of the piston 24 in its uppermost position. This port 3| opens into a chamber cooperating with a valve seat 32a provided by the housing 32. A valve 33 cooperates with this seat, being normally urged toward an open position, as illustrated, by a spring 34. When the valve is in this open position and the piston 24 is below the port 3| gases in the chamber may pass out through the port 3|, between the valve and its seat, and outthrough the opening 35 to atmosphere.

The relief valve 33, however, must be closed during the explosion and downward movement of the piston 24 inorder to avoid loss of power and resultant diminishing of the leap; and yet this 4 valve must stand open during upward movement of the piston 24, after the force of the explosion has been spent, to relieve the pressure which would otherwise retard return movement of the lower piston and foot.

Since the spring 28 beneath the lower piston 24 is a fairly strong spring, sufficient upward movement of the piston 24 to close off the ports 27 may take place before the pressure in the combustion chamber has dropped completely to atmosphere; in fact, there may be several pounds per square inch pressure in the chamber at all times. We have found it necessary to make the spring 34 of sufficient strength to open the valve 33 even though there may be several pounds per square inch pressure on it. On the other hand, the spring must not be too strong or it will open the relief valve near the end of the explosion period, but before the piston 24 has gotten to its lowermost position in the cylinder; and this will result in a loss of jump. In fact, too heavy a spring 34 can result in the loss of almost half of the jump.

If the spring strength is properly proportioned with respect to the area of the head of the valve 33, however, the relief valve will close instantly when the piston rings pass below the top of the port 3|, and remain closed until the spring 28 has bottomed or become solid, which we arrange to take place slightly before the bottom of the piston would otherwise strike the shoulder at the upper end of the lower body portion C, to protect these parts from damage; and then the relief valve 33 will open, permitting unretarded return of the piston 24 until the rings have passed the port 3!. Since the rings are practically at the upper limit of their movement at this time, no substantial compression takes place above the piston and the piston and foot return to uppermost position (relative to the body) rapidly. We have found that .a very good relationship between the spring 34 and the valve 33 is one which will just open the valve, from an initially closed position, against a pressure of between five and twenty pounds per square inch in the cylinder, one very satisfactory embodiment of our invention having the arrangement such that the valve 33 would just open against a pressure of seven pounds per square inch.

If a spring of too great strength is used, as one opening the valve from closed position against a pressure of twenty pounds per square inch or more, the valve does not close quickly enough when uncovered by the top ring of the piston and may open before the explosion stroke is really completed, reducing the efficiency and jump of the rammer. The simple poppet valve arrangement can be used because of proper spring proportioning; and by locating the port opening to this valve below the top ring of the piston 24 in uppermost position the most efiicient operation is obtained, there being no opening to the valve from the cylinder at the instant of explosion. Previous attempts to provide an auxiliary relief valve have incorporated a passageway opened to the combustion chamber at all times, and complicated slide arrangements which stuck and were otherwise unsatisfactory after an extremely short period of use.

Another difficulty heretofore encountered with rammers of this type has been failure of the carburetor inlet valve, and we have provided a protective arrangement. Referring now more particularly to Figures 4 and 5, the carburetor and protective arrangement will be described.

Ma controlled by a needle valve t2 and communicating with a gasoline feed pipe l3 leading up to an opening into the bottom of the gasoline tank 54, which is located at the top of the ram mer, this communication being through a strainer device 45. In rammers of the type here being discussed it has heretofore been general to show the fuel tank at the very bottom of the body. generally with some kind of a capillary feed to the carburetor which proved very unsatisfactory. Location :of the fuel tank at the top of the ram-- mer body has heretofore been considered undesirable, not only from .a weight distribution standpoint, but also because the heat rising from the combustion chamber would, cause the gasoline to boil, with resultant vapor loss. particularly in hot weather. It has also proved imprac tical to mount the gasoline tanks at the side of 1 the cylinder, as is done in some other internal combustion devices, since these rammers are frequently used in backfill work in narrow trenches, or close to the side of a bank, where maintaining the outside dimensions of the device at a minimum, and substantially uniform from top to bottom, are important.

We have found that we can locate the fuel tank at the top by so local, gasoline weight on one side of the center of the rammer by magnetic weight on the other side and achieve proper balance; and that we can provide an air cooled zone between the top of the cylinder and the bottom of the gasoline tank which prevents overheating. To be sure of positive air circulation between the cylinder head and the bottom of the gasoline tank we arrange air openings, as the air openings 5i? between the ribs 5! supporting the fuel tank above the plate 353, as may be best seen in Figures 1 and 3. By supporting a fuel tank on relatively thin ribs direct heat conduction from the plate 36 is minimized; and much of the heat passing up the ribs is dissipated by the cooling effect of air therearound. Positive movement of air in this space between the plate 39 and the fuel tank M is effected primarily by the upward and downward movement of the parts carried by the center plunger iii, and to some extent by the intake of air for the carburetor through the sceen all and tube 45a, this latter being a flexible conduit leading from the intake section on the top of the plate to the carburetor. When upward movement of the piston l8 has created a vacuum in the combustion chamber and lifted the valve 48 from its seat air flows down through the conduit 4-3 and up around the valve All, drawin liquid gasoline through the orifice Ma and mixing it with the air to provide combustible charge in known manner.

The principal advantage of using an air intake of the kind illustrated, however, is in minimizing difficulty with dirt particles getting into the carburetor and into the body of the rammer. Tamping work throws up a cloud of dirt, and direct air intake at the bottom of the carburetor is unsatisfactory. By locating the screen M5 on top of the plate 36 it is protected from being struck directly by any dirt thrown up by the tamping action; and the screen serves to filter out small dust particles floating in the air. Use of a screen on an opening directly at the base of the carburetor is impractical, as dirt thrown up by the tamping clogs it after a short period of operation.

In previous rammers the carburetor value All been exposed directly to 'th'eheataef the :burning gases during the explosion-in the combustion cylinder, heating this valve substantially. Car-- bon formation can thus take place directly at the valve. In addition, the valve would be considerably heated and then on the next inlet stroke relatively cool gasoline "would contact one point of its periphery, cooling this one point very drastically, resulting in frequent warpage-of the valve with resultant failure to seat properly and shut off gasoline flow between intake operations.

We overcome these difficulties by providing-a protective valve 58 between the carburetor valve and the combustion chamber, as may be best L3. in Figure 4. During the intake operation ves 2% and it are both open and the air-gas mixture is sucked into the combustion chamber; and during the explosion and the return movement of the piston at both of these valves are closed. During this time, however, the valve .48

provides a seal between the carburetor valve. All

and the combustion ases and the combustion heat. This has resulted in greatly increasing the satisfactoriness of operation of the carburetor; in fact, practically rendering it trouble free. We have found it preferable to make the upper valve of a somewhat greater area than the lower valve, preferably at least 50-35% ter in area; and to make the sprin load of upper valve slightly greater than that .of the lower valve, proportionately to its area. We prefer to have the vspring-loading--area relationship of these valves such that it takes a slightly greater force to lift valve 48 from its seat, so that the instant this valve lifts the carburetor valve it! immediately lifts; and so that, upon completion of the inlet stroke and at or before the instant of the explosion taking place in the cylinder, the valve lib closes, if anything, slightly ahead of the valve lli. The valve spring used in conjunction with the carburetor valve to must be quite light, preferably with a pressure of only a matter of ounces when the valve is closed, and the use of a heavier spring on the valve 4%. eliminates loss of power which sometimes otherwise took place through bounce of the intake valve as the result of vibrations incident to operation of the rammer. Moreover, the use of a smaller valve as the lower or carburetor valve makes this lower opening more restricted than the upper one and results in an increase of velocity of the air flowing past this valve, insuring positive drawing into the air stream of not only gasoline but also of oil mixed with the gasoline in lubrication. In devices of this character there has sometimes heretofore been a tendency for the oil not to pass on into the combustion cylinder in the desired ratio to the gasoline, as it was initially mixed in the fuel tank, but to separate out at the carburetor and leak out at this point without providing the necessary lubrication in the working cylinder of the machine.

While I have shown and described certain emembodiments 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.

We claim:

1. An internal combustion rammer of the character described, including: a body portion having a cylinder therein; a piston movable in said cylinder; a ramming foot connected to and movable with said piston; means for delivering a combustible charge to said cylinder and igniting the charge to move the piston and foot downwardly relative to said body portion; a piston spring for returning the piston and foot relatively upwardly; principal exhaust port means in said cylinder so located as to be uncovered by the piston only near the end of its downward movement; an auxiliary exhaust arrangement consisting of only a single exhaust opening, located in said cylinder at such a point as to remain uncovered by the piston during at least the major portion of its return movement eflfected by the spring but to be covered by the piston by the end of its return movement; a poppet valve member for closing said exhaust opening this valve member being located in said opening so that explosion pressure admitted to said opening from the cylinder is effective against its head to move it to closed position; and a spring normally urging said valve member to open position, said spring being weak enough to permit the pressure in the cylinder during the entire explosion stroke to keep the valve member closed until the exhaust port means has been uncovered by the piston but strong enough to keep the valve member open against scavenging pressure during return movement of the piston, whereby spent gases exhaust through said same opening through which explosion pressure gases were admitted to actuate said valve.

2. Apparatus of the character claimed in claim 1, wherein the valve sprin is of such a strength 8 as to just open the valve member, from closed position, against a pressure thereon of between 5 and 20 lbs. per square inch.

3. Apparatus of the character claimed in claim 1, wherein the valve spring is of such a strength as to just open the valve member, from closed position, against a pressure thereon of about 7 lbs. per square inch.

VICTOR W. BREITENSTEIN.

EM'MONS R. BODDINGI-IOUSE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 911,187 White et al Feb. 2, 1909 1,034,053 Wyer July 30, 1912 1,647,554 Trapnell Nov. 1, 1927 1,666,981 Somervell Apr. 24, 1928 1,920,765 Rasch Aug. 1, 1933 2,027,080 Wilcox Jan. 7, 1936 2,07 ,266 Kiecksee Mar. 2, 1937 2,112,672 Lasley Mar. 29, 1938 2,214,800 Smith Sept. 17, 1940 2,292,942 Horner Aug. 11, 1942 2,333,419 Fitch Nov. 2, 1943 FOREIGN PATENTS Number Country Date 395,524 Great Britain July 20, 1933 749,121 France May 2, 1933

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