US3822969A

US3822969A - Fuel injection pump for a diesel assisted ram

Info

Publication number: US3822969A
Application number: US00303397A
Authority: US
Inventors: F Kummel
Original assignee: Delmay Maschinenfabrik Reinhold Dormfeld
Current assignee: Delmay Maschinenfabrik Reinhold Dormfeld
Priority date: 1971-11-06
Filing date: 1972-11-03
Publication date: 1974-07-09
Anticipated expiration: 1991-07-09
Also published as: DE2155310C3; NL7214873A; NL176801C; DE2155310A1; CA959727A; FR2160008A5; DE2155310B2; NL176801B; GB1372902A

Abstract

A fuel injection pump for a diesel-assisted ram, pile driver or the like having a cylinder in which a ram piston is adapted to strike a percussion head. The pump comprises a compression chamber, a pump piston movable therein, an inlet from a reservoir of fuel and an outlet to the ram cylinder. A lever pivoted within the plane of the wall of the ram cylinder to extend into the path of the ram piston. The lever is displaced by the ram piston to move the pump piston to force fuel from the chamber to ram cylinder. Means are provided for adjusting the path of movement of the lever to vary the stroke of the pump piston and the volume of discharged fuel.

Description

United States Patent 1191 11] 3,822,969 Kiimmel July 9, 1974 FUEL INJECTION PUMP FOR A DIESEL 168,527 4/1934 Germany 92/13."; ASSISTED RAM [75] Inventor: Fritz Kiimmel, Esslingen, Germany Primary Examiner wiuiam Freeh [73] Assignee: Delmay-Maschinenfabrik Reinhold t y, g or i mMurray Shaffer dormfeld, Esslingen, Germany 22 Filed: Nov. 3, 1972 p [2]] Appl. No.: 303,397 [57] ABSTRACT A fuel injection pump for a diesel assisted ram, pile [30] Foreign Application Priority Data driver or the like having a cylinder in which a ram pis- Nov. 6, 197] Germany 2155310 ton is adapted to Strike a percussion head. The pump comprises a compression chamber, a pump piston [52] [1.8. CI. 417/4332 922/1131 movable therein an inlet from a reservoir of fuel and an Outlet o the ram Cylinder A lever p o [58] held of Search 12 I3 4 7 the plane of the wall of the ram cylinder to extend into the path of the ram piston. The lever is displaced by [56] References cued the ram piston to move the pump piston to force fuel UNITED STATES PATENTS from the chamber to ram cylinder. Means are pro- 2,3 O5,772 12/1942 Haage 123/32 R vided for adjusting the path of movement of the lever 2,740,385 4/1956 Haage 123/32 R to vary the stroke of the pump piston and the volume 3.8 of discharged fueL FOREIGN PATENTS OR APPLICATIONS 562,826 7/1944 Great Britain 92/ 13.7 8 Claims, 4 Drawing Figures x is I 94 7r 88 22* 820 4!- 90 82 u 86 9 76 by 76o 80 I 24 7 1 o 1 I 1/ 84 1.2 1

1.6 1 v f 21. 56 I 60 54 I 1.8

1 III V; 64 w I so 52 s2 as 58 70 74c 7 72% I l FUEL INJECTION PUMP FOR A DIESEL ASSISTED RAM The present invention relates to a fuel injector pump for a diesel and/or internal combustion assisted ram, pile driver or the like.

Diesel-assisted or internal combustion assisted pile drivers, hammers, or the like (the terms are used interchangeably) are well known. Briefly, such apparatus comprises a housing mounted to be adjustable and/or movable on a vertical standard or scaffold. The housing defines a ram cylinder having a percussion piece at one end adapted to strike the pile or other work piece and ram piston movable to strike the percussion piece. The ram piston is generally lifted by a hoist or other pulley system and allowed to drop on the percussion piece. In diesel-assisted rams of this type, a combustion fuel is sprayed into the cylinder and is compressed by the downwardly moving ram piston untilit explodes. The explosion forces the percussion piece with greater force on to the pile or workpiece while simultaneously lifting the ram piston upwardly, preparatory to another cycle.

In diesel-assisted rams in which the fuel is to be atomized in order to obtain the maximum explosion, the injection'of the fuel into the ram cylinder is to be carefully regulated. The splitting of the fuel stream in or by the nozzle must be avoided so that a deviation in pressure or velocity is avoided. It is also desirable to have the fuel injected at a constant uniform and proportionately low pressure. A suitable pump for dosing the fuel in such a way is required. A further advantageous need is to provide a fuel pump which has means for adjusting the stroke of the pump easily and simply.

Injection pumps are known for use in diesel-assisted rams; The pumps comprise a chamber in which a movable pump piston is arranged, the stroke of which is activated by. an upright lever which extends through the housing of the ram and which is displaced in each cycle by the downward movement of the ram piston itself. The pump chamber has an inlet from a fuel tank and an outlet leading to the spray nozzle. Conventionally the inlet from the tank lies in the circumferential area of the chamber and in the path of the stroking pump piston.

The conventional pumps having a vertical lever for activating the pump piston, causes a high degree of wear and abrasion on the ram piston as well as on the lever itself, since the construction of the lever itself gives rise to the certain of large reactive shock and impact forces. In retrospect, therefore, the lever must be built to be very strong; that is, very large and heavy. Therefore, in order to return the lever to its starting position for each cycle, proportionately very large forces must be exerted on it. Further, additional disadvantages must be taken into account, should a pump with an upright standing lever be provided with means for adjustment of the fuel discharge volume. Either an additional adjustment displacement piston must be provided in the pump, or the path of the-activating lever must be changed, that is, it must be possible to adjust vated. This cam piece must have an enlarged or sharply increasing node or cam edge so as to be engaged by the piston at start-up and when the lever is, in fact, inserted at its furthest distance. As a result or providing the lever with the cam piece the lever is actually susceptible to even greater forces of acceleration creating, resulting in stronger stresses on the pump and ending in the injection of the fuel at a higher and undesirable pressure. I

It is the object of the present invention to provide a fuel injection pump which avoids thedifficulties of the prior art and which permits the simple and easy adjustment of the fuel discharge volume.

According to the present invention a pump is provided by which the pump piston is activiated in a continuous stroke by a lever displaced by the movement of the ram piston. The lever is provided with means for adjusting more or less the degree to which it enters into the ram cylinder and into engagement with the ram piston. The lever comprises a two arm bell crank and the adjustment means comprises an adjustable sto'p member engaging one arm to limit and define the degree of pivoting of the crank.

Furthermore, the inlet for the fuel to the pump chamber is arranged at the end of the chamber facing the pump piston or beyond the stroke of the piston, so that on varying the pump stroke on activation of the lever the amount of fuel discharged can be changed.

In this arrangement the lever is a double arm device, having one arm which projects from a fixed pivot point on the wall of the ram cylinder into the ram cylinder. This arm engages the ram piston and also engages and operates the pump piston. The other arm of the lever engages the stop member and defines the limit of movement and stroke. The arm projecting into the ram cylinder is preferably made with an inclined edge or drag surface which is progressively and gradually engaged by'the ram piston into its full compression stroke. Thus the piston is caused to also operate in smooth gradual strokes forcing the fuel into the spray nozzle under a steady uniform pressure. Since the lever is easily adjusted and pivots into the chamber at varying angles determined by the stop means, the length of the pump stroke may be correspondingly changed. However, since the edge of the lever is continuous and linearly inclined the smooth gradual pump stroke and pressure of discharge is not effected. The entire edge of the lever comprises a cam surface, and the increase in pressure stroke is proportionately constant. Creation of sudden shock and large uneven reactive forces etc'., are fully avoided.

In connection with the provision of this drag lever construction, there arises a very special advantage in that a more roomy or commodious construction is obtained. The pump piston can be arranged perpendicularly to the axis of the ram cylinder and therefore be more easily activated by the lever. The width of the entire' pump need be significantly no larger than the entire assembly of pump piston and pump chamber. The adjustment means, may be arranged to the side or top or bottom of the pump piston and chamber and be offset from it since it no longer is dependent upon it to effect adjustment of the stroke.

The adjustment mechanism comprisesa stop member formed of a plunger, one end of which engages the activating lever, the other end of which engages the peripheral edge of a cam plate. The cam plate is fixed to a rotatable shaft on which a pulley is also fixed and over which a manually operable cable is trained. A locking pawl mechanism may engage either the cam plate or a separate ratcheted disk mounted on the rotatable shaft. By pulling on the cable the cam plate may be caused to rotate thereby moving the plunger and the lever. The cam is contoured with a varying radius to provide for a wide range of movement of the activating lever and is provided with means for selective indexing to adjust the position of the lever during operation.

This particular arrangement of adjusting mechanism has a decided advantage in insuring normal operation and in the feeding of the fuel in a consistent uniform manner, since once the stop plunger is adjusted it remains secure during operation, and is not dependent on variable displacement pistons or the like. Sometimes, on startup of the ram of the prior art, an upright lever fails to retract sufficiently or the pump piston fails to return to its initial position, after the rise of the ram piston after the first explosion. Thus the pump may fail to operate on the next downward stroke of the ram piston and will fail to feed a supply of combustion fuel to the ram cylinder. Should this occur then it is desirable to be able to manually induce the feeding of the fuel, (i.e., manually operate the pump). Here, the provison of the cable to rotate the cam plate enables this to be done. Simply by contouring the periphery of the cam plate with a high point directly adjacent the normally operating cam surface a tug or pull on the cable will momentarily displace the lever its maximum distance and cause it to activate the pump piston regardless of the condition it was in. Thus, a maximum amount of fuel can be injected into the ram cylinder during the intake phase of the explosion cycle. This can be done, as will be obvious, at any time, when the ram piston is ascending from the percussion piece.

In the previously known devices employing a stationary lever the lever enters the slot wall of the cylinder but the pump housing lies beneath the slot. The creation ofthe slot itself weakens the wall of the ram cylinder and sometimes leads to a rupture of the cylinder wall and may cause serious breakdown and injury. This problem is avoided with the present invention. Since the lever comprises a drag lever extending the length of the slot, and is not activated from above the pump. The pump housing may be made to lie all around the slot particularly to either side of it. Since also the lever lies in front of the pump and not to its sides, the pump housing may be securely attached to the cylinder by screw bolts which will not only secure the pump but strengthen the entire cylinder wall.

Full details of the present invention follow herein and will be seen from the accompanying drawings where a preferred embodiment thereof is depicted.

In the drawings:

FIG. I is a side elevational view of a diesel-assisted ram, pile driver, or the like,

FIG. 2 is an enlarged exterior view of the fuel injection pump of the present invention,

FIG. 3 is an enlarged sectional view along lines 33 of FIG. 2, and

FIG. 4 is a sectional view along lines 4-4 of FIG. 3.

Before turning to the description of the preferred embodiment of this invention, reference is made and incorporation made of copending applications of the assignee hereto Ser. No. 303,394 and Ser. No. 303,395

both filed on even date hereof, corresponding respectively to German Applications P 21553060 and G 71420343, which show other aspects of a ram or pile driver or type hereunder discussion. Reference can also be made to Hennecke, Ser. No. 258,896, filed June 1, 1972 and to German Pat. Nos. 2,040,924, and 1,030,915.

While in general, the present invention may be applied to conventional apparatus of the type earlier described, reference can be made to the above for any details thereof, not deemed necessary to be shown herein.

A tubular vertical scafford or support 10 is seen in FIG. 1, on which a diesel and/or internal combustionassisted pile driver or ram 12 is movably supported by guide brackets 14. The ram is provided with a fuel injection pump 16 seen from the exterior of FIG. 2. As seen in FIG. 2, a portion of the cylinder wall of the ram 12 is formed with a vertical slot 20 extending parallel to its central axis. One am of a double armed activating lever 22 of the injection pump 16 passes through the slot and is adapted to engage the ram piston movable in the cylinder 18. The housing 24 of the injector pump is fastened by means of a not shown gasket or spanning sleeve and a plurality of screw bolts 26 to the outer surface of the cylinder 18, on both sides of the slot 20. The housing 24 extends partially into the slot 20 but is large enough to sufficiently cover the slot completely. Therefore, the housing and the bolts act to enclose and strengthen the wall of the cylinder. Extending outwardly of the housing 24 is a cable 28 by which means the pump may be manually operated to vary and cause instantaneous discharge of fuel, as will be later described. Combustion fuel is delivered via a conduit 30 from a reservoir tank 32 built onto the outer housing or cylinder wall. A second conduit 31 between the pump and the tank is used for removing air out of the pump, e.g., after filling of the empty tank.

The construction of the injection pump is seen in greater detail in FIGS. 3 and 4. The activating lever 22 is pivoted about a pin 40 secured in the upper end of the housing 24 along the vertical wall of cylinder 18. The lever comprises a bell crank having an elongated lever arm 42 and a short lever arm 44. In the area near the end of the long arm 42, the pump housing 24 is formed with a bore 46, which extends at right angles, perpendicularly to the longitudinal axis of the ram cylinder. The inner end of the bore 46 is provided with a cylinder sleeve or lining 48 in which a pump piston 50 is arranged. Extending outwardly of the open end of the bore 46 is a hollow plug cap 52 secured to the end of a piston rod 54 which is itself secured to the piston 50. The piston rod 54 has a head 56 at its end adjacent the bottom of the plug 52. Surrounding the piston rod and supported by it is a disk 58 which is normally urged against the head 56 by a spring 60, the rearmost end of which abuts against a second disk 62. The spring 60 acts to normally bias the piston 50 and the plug 52 outwardly of the pump cylinder (i.e., toward the left, as seen in FIG. 3) and to return the piston 50 after each inward pumping action. The cylinder liner 48 and the disk 62 form an enclosed compression chamber 64 into which a fuel inlet line 66 debauches. The fuel inlet line 66 leads from conduit 30 and includes a non-return valve of conventional design to insure unidirectional flow of fuel. The inlet line 66 enters into the compression chamber at the end of the bore 46 opposite the vided with a non-return valve 74 which can be opened.

by the pressure of the combustion fuel in bore 71 acting on shoulder 74aof the valve.

The long lever arm 42 has a shaped edge extending I into the ram cylinder. This edge comprises a smooth straight curve which forms an inclined drag surface so that the ram piston seen in dotted lines in FIG. 3 can cause it to be displaced in a smooth steady constant pressing. An adjusting device for limiting the path of movement of the activating lever 22 is shown by, generally, numeral 76 and comprises a rotatable axle shaft 78 on which a curved cam plate 80 is fixed. Rotatably supported on the shaft 78 is a pulley 82, over which the cable 28 isentrained, and aratcheted or toothed disk 84 is fixedly mounted on the shaft 78. A pair of locking pawls 86 are pivotably attached to the pulley and engage in the teeth of disk 84. Thecable 28 has a central fixed sleeve 28a which hooks on to the pulley. The pulley is provided with a spring 82a to normally hold it in and return it to a mid-position shown in FIG. 4. The pulley is also provided with an arcuate slot 82b through which a pin 24a fixed to the housing wall, extends. This pin does not only limit the degree of movement of the pulley but also releases one of the pawls 86 when the ratchet disk 84 is rotated by pulling on the cable 28 in either direction so that the ratchet disk 84 together with the cam plate 80 is not returned to the initial position when the pulley 82 together with the pawls 86 is returned in its mid-position by spring 82a. The pulley serves to permit the cam plate to be indexed in defined increments or steps, predetermined by the interval between the teeth of the ratchet disk 84. It is to be emphasized that the locking pawls 86 permit the rotation of the cam 80 in both directions.

In the pumphousing 24 there is provided a further stepped bore 88 in which a plunger 90 is movably located. The bore 88 is vertical and perpendicular to the pump piston 46. The plunger 90 has a head 92 lying in the enlarged portion of the bore 88 and between which and the shoulder of the bore 88 there is arranged a spring 94.'The plunger 90 lies between the end of the short arm 44 of the lever 22 and the peripheral edge of the cam plate. 80. Consequently, as a result of the urging of the spring 60 surrounding the pump piston 54, the lever 22 is normally urged clockwise, forcing the plunger 90 directly into contact with the peripheral edge of the cam plate 80. Of course, the spring rate or force of spring 60 is greater than that of spring 94 surrounding the plunger.

The form of the peripheral edge of the cam plate 80 is seen in FIG. 4. The direction of swing of the activating lever 22, when contacted by the descending ram piston is greatest when the peripheral area of the cam plate 80 beneath the plunger 90 is of the smallest radius. This is indicated by the double arrow R. Generally, this position is selected-on start-up operation of the pile driver or ram. The contour of the cam plate 80 increases in radius to the left of point R until the largest or high point 100 is obtained. This provides successively decreasing loss of fuel since the stroke of the lever 22 will be lessened. However, the positioning of the high point 100 directly at the end of the area of lowest radius R permits the cam plate to be operated manually 'to cause the lever 22 to provide a long stroke to thereby feed a maximum quantity of fuel to the nozzle. Thus, by pulling counter-clockwise on the cable 28, the plunger 90 can be made to go instantaneously from a position where it rides on the lowest cam surface to a position where it rides on the highest cam surface. This causes the lever to move in an extreme counterclockwise path depressing the pump piston 50 its full extent and causing it to feed a full dose of fuel to the nozzle 72. I

The fuel injector pump functions as follows:

As the ram piston is caused to fall in the ram cylinder, it passesand runs against the edge of the long arm 42 of the lever 22 and pushes it correspondingly, gradually and smoothly counter-clockwise to the right against the cap 52. This causes the pump piston 50 to force the combustion fuel previously fed to chamber 64 through the outlet 68 into the injector nozzle-72. The fuel is prevented from exiting through conduit 66 by the nonreturn valve and is thus injected into the nozzle 72 and by the converging ram piston and percussion head,

forcing the percussion head and ram piston apart. As the ram piston rises, as a result of the explosion, it frees the long lever arm 42. The spring 60 and the pump piston 50 are again forced to the left to the original starting position. As a consequent, the piston 50 creates a vacuum in the chamber 64 causing a fresh supply of combustion fuel to be sucked in via inlet 66. The path of lever 22 and therewith the stroke of the pump 50 is limited and defined by the plunger and is selectively obtained by adjustment of the cam plate 80. If after the first explosion in the ram cylinder, the lever 22 is not freely released to cause pumping in the next cycle, then fuel can be manually admitted easily during the next intake phase of the ram by simply pulling counterclockwise on the cable.28, with a strong movement. The-swift jerk of the cable 28 causes the cam plate to move from its small radial area to the high point 100. A spring 84a biasing the right hand pawl permits this to happen since both pawls will remain engaged with the toothed disk. The pulley is returned to its starting position by action of spring 82a. Thus should the cam plate be at its smallest radius, as at the start-up movement of the cable counter-clockwise causes it to immediately, to be moved to the high point 100, which forms its boundary, as noted in FIG. 4. The high point of the cam plate causes the plunger 90 to move the lever 22 counter-clockwise and consequently move the pump a piston 50 to the right forcing the fuel in the compres sion chamber 64 into nozzle 72. The pump operation proceeds automatically and cyclically and requires little attendance.

It will also be seen that the pump provides a secure and effective means for dosing and delivering a quantity of fuel. Each stroke of the pump piston supplies a consistent and uniform quantity as each other stroke, and the quantity changed only when the cam plate is moved and placed in a new adjusted position.

Various changes, modifications and alterations can be made as indicated in the previous disclosure of the preferred embodiment and as will be obvious to those skilled in this art. The present disclosure is intended to be illustrative only and not limiting of the scope of the invention.

What is claimed is:

l. A fuel injection pump for a diesel-assisted ram, pile driver or the like having a cylinder in which a reciprocating ram piston is adapted to strike a percussion head, the pump comprising a compression chamber, a pump piston movable therein, said chamber having a fuel inlet from a reservoir of fuel and a fuel outlet to the ram cylinder, a pivotal lever extending into said cylinder along the path of the ram piston, said lever being displaced by said ram piston to move said pump piston to force fuel from said chamber through said fuel outlet, and an adjustable stop abutting against said lever regulating the path of movement of said lever to vary the stroke of said pump piston and the volume of dis charged fuel.

2. The pump according to claim 1 wherein said inlet for fuel is arranged at the end of said chamber opposite the pump piston.

3. The pump according to claim 1, wherein the ram cylinder has a slot through which said one arm of the drag lever extends, the other arm of said drag lever being housed in a pump housing secured to said ram cylinder on both sides of said slot.

4. The pump according to claim 1 wherein said lever comprises a bell crank having a pair of arms pivoted at its center, one of said arms having a surface adapted to drag against said ram piston, the other arm being adapted to abut against said adjustable stop.

5. The pump according to claim 4 wherein the pump piston lies perpendicular to the longitudinal axis of the ram.

6. The pump according to claim 4 wherein the adjustable stop comprises an elongated plunger having one end abutting said other arm of the lever and the other end abutting the periphery of a rotatable cam plate.

7. The pump according to claim 6, including a manually operable adjusting mechanism for the cam plate, the latter having a peripheral surface with a portion corresponding to a maximum of discharged fuel and with an additional projection for discharging additional fuel through said fuel outlet, said projection being arranged adjacent said portion.

8. A fuel injection pump for a diesel-type ram, pile driver or the like, having a cylinder in which a ram piston is reciprocating, the pump comprising a compres sion chamber, a pump piston movable therein, a fuel inlet from a reservoir of fuel and a fuel outlet to the ram cylinder, said fuel inlet being arranged beyond the path of the pump piston, a drag lever having a pair of arms, said lever being pivoted between said arms and having one arm extending into said cylinder and along the path of the ram piston, said one arm being displaced by said ram piston to move said pump piston to force fuel into said fuel outlet, and means for adjusting the path of movement of said drag lever to vary the stroke of said pump piston and the volume of discharged fuel, said means comprising an adjustable stop abutting against the second of the arms of said drag lever.

Claims

1. A fuel injection pump for a diesel-assisted ram, pile driver or the like having a cylinder in which a reciprocating ram piston is adapted to strike a percussion head, the pump comprising a compression chamber, a pump piston movable therein, said chamber having a fuel inlet from a reservoir of fuel and a fuel outlet to the ram cylinder, a pivotal lever extending into said cylinder along the path of the ram piston, said lever being displaced by said ram piston to move said pump piston to force fuel from said chamber through said fuel outlet, and an adjustable stop abutting against said lever regulating the path of movement of said lever to vary the stroke of said pump piston and the volume of discharged fuel.

8. A fuel injection pump for a diesel-type ram, pile driver or the like, having a cylinder in which a ram piston is reciprocating, the pump comprising a compression chamber, a pump piston movable therein, a fuel inlet from a reservoir of fuel and a fuel outlet to the ram cylinder, said fuel inlet being arranged beyond the path of the pump piston, a drag lever having a pair of arms, said lever being pivoted between said arms and having one arm extending into said cylinder and along the path of the ram piston, said one arm being displaced by said ram piston to move said pump piston to force fuel into said fuel outlet, and means for adjusting the path of movement of said drag lever to vary the stroke of said pump piston and the volume of discharged fuel, said means comprising an adjustable stop abutting against the second of the arms of said drag lever.