Patent Application
20150129270
Applicant claims priority under 35 U.S.C. §119 of European Application No. 13 192 602.4 filed Nov. 12, 2013, the disclosure of which is incorporated by reference.
1. Field of the Invention
The invention relates to a diesel hammer pile driver having a cylinder, a piston displaceably guided in the cylinder, and a striker displaceably guided in the cylinder.
2. Description of the Related Art
Diesel hammer pile drivers, also called diesel hammers or diesel pile drivers, are particularly used in foundation work in the construction industry. The diesel hammer pile drivers are used for driving posts of all kinds, such as concrete pillars, iron beams, sheet pile wall elements or the like into a construction ground.
To start such a diesel hammer pile driver, the piston is pulled upward within the cylinder, using a disengagement apparatus, and disengaged at a specific height, thereby dropping downward onto the striker, under the effect of gravity. As it drops, the piston activates a fuel pump, by way of which feed of fuel, particularly diesel oil, takes place. The fuel of the diesel hammer pile driver is contained in a tank that is welded onto the outside of the cylinder of the diesel hammer pile driver and connected with the fuel pump by way of a line. The air situated in the combustion chamber of the cylinder is compressed by the dropping piston, and thereby heated so that the fuel/air mixture present in the combustion chamber is ignited, whereupon it combusts in the manner of an explosion. As a result of the explosion energy released during this process, for one thing the piston is accelerated back upward for a new work cycle; at the same time, the material being pile-driven is driven into the ground by way of the striker.
Diesel hammer pile drivers of the aforementioned type, as it is described in EP 1 828 488 B1, for example, have proven themselves in practice because of their simple structure and their related great reliability. In operation, however, such diesel hammer pile drivers are very loud and can cause a noise level of 100 decibels (A) and more.
The invention wishes to provide a remedy for this situation. The invention is based on the task of making available a diesel hammer pile driver of the aforementioned type, the noise emission of which is reduced. According to the invention, this task is accomplished by means of a diesel hammer pile driver having a cylinder, a piston displaceably guided in the cylinder and a striker displaceably guided in the cylinder. The striker is disposed underneath the piston in the operating position of the diesel hammer pile driver, and a combustion chamber is provided. The combustion chamber is delimited axially by a face surface of the striker that lies in the interior of the cylinder, and by a face surface of the piston, and opens into a fuel feed device connected with a fuel tank disposed on the outside of the cylinder. By means of this device, a predetermined amount of fuel can be introduced into the combustion chamber during each working cycle. The fuel tank is elastically mounted on the cylinder.
With the invention, a diesel hammer pile driver of the aforementioned type is made available, the noise emission of which is reduced. Because the fuel tank is elastically mounted on the cylinder, the tank is uncoupled from the cylinder body. Surprisingly, it has been shown that the fuel tank welded to the side of the cylinder in the state of the art represents a significant resonance body that contributes, to a significant extent, to the noise emission of the diesel hammer pile driver. A significant reduction in the noise emission of the diesel hammer pile driver is achieved by uncoupling the tank from the cylinder.
In a further development of the invention, two crosspieces are disposed on the cylinder, on the outside, parallel to one another, on which the tank is attached by way of vibration elements. In this way, efficient uncoupling of the tank from the cylinder is achieved. The vibrations of the tank that occur are damped by means of the vibration dampers. Preferably, the vibration elements are configured as elastomer components or rubber components. Such vibration dampers are available in the state of the art, in the most varied embodiments and methods of effect.
Other objects and features of the invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.
In the drawings, wherein similar reference characters denote similar elements throughout the several views:
Referring now in detail to the drawings the diesel hammer pile driver shown in
A strike plate 32 is formed onto the lower end of the shaft section 31, lying underneath the cylinder 1, the lower convex delimitation surface 33 of which plate, directed outward, interacts with the upper end of a material to be pile-driven, during operation.
A piston section 34 having multiple circumferential sealing rings, axially at a distance from one another, which run on the inner mantle surface 11 of the cylinder 1, is formed on at the upper end of the shaft section 31 of the striker 3. A combustion chamber 12 is delimited by the top of the piston section 34 of the striker 3, together with the underside of the piston 2, as well as the inner mantle surface 11 of the cylinder 1. The face surface of the striker 3 that faces the combustion chamber 12 of the cylinder 1 is ground to be level with a flat fuel bowl.
A damping ring 91 is disposed between the strike plate 32 of the striker 3 and the bearing unit 9 of the cylinder 1. A further damping ring 92 is disposed adjacent to the bearing unit 9, between the top of the bearing unit 9 and the underside of the piston section 34 of the striker 3.
A lower working end 23 of the piston 2, provided with circumferential sealing rings 93 that are axially spaced apart from one another, runs in the interior of the cylinder 1, above the striker 3. The lower, free face surface 21 of the piston 2, ground to be planar, is set off by a circumferential step that lies radially on the outside.
A mass section 22 that extends into the upper section of the cylinder 1 is formed onto the lower working end 23 of the piston 2. An injection apparatus 4 is disposed on the circumference wall of the cylinder 1, which apparatus comprises a fuel pump 41 that is connected with the injection nozzle 42 by way of a line 43. The inlet of the fuel pump 41 is supplied with diesel oil by way of a fuel tank 5.
In the exemplary embodiment, the fuel tank 5 is configured as a sheet-metal container, on the opposite top side and bottom side of which a flange 51 is formed, in each instance. See
The fuel pump 41 connected with the fuel tank 5 by way of the line 43 has a biased pump lever 44 that projects into the interior of the cylinder 1, by way of which the pump is driven when the dropping piston 2 goes past. The injection nozzle 42 is configured and oriented in such a manner that the fuel emitted is sprayed approximately in the center of the face surface of the striker 3, in an essentially cohesive jet.
Furthermore, a lubricant pump 7 is disposed on the cylinder 1, which pump is connected with lubricant nozzles distributed in the circumference direction of the cylinder 1. Lubricant is dispensed between the piston 2 and the inner mantle surface 11 of the cylinder 1 by the lubricant nozzles.
The diesel hammer pile driver described above works as follows: In the starting state, the piston 2 is raised into an upper position by way of the disengagement apparatus—not shown. After disengagement, it falls downward from there, under the effect of gravity, closes the working connectors 16, and activates the pump lever 44 of the injection apparatus 4 with its face surface 21, thereby causing fuel to be sprayed onto the fuel bowl of the striker 3 by way of the injection nozzle 42. Here, an ignitable mixture of fuel droplets and air forms by means of impact atomization.
When the piston 2 impacts the striker 3, a force directed downward is exerted on the striker 3 and, by way of the latter, on the material to be pile-driven, which force drives the material to be pile-driven further into the ground. During the subsequent upward movement of the piston 2, triggered by the explosion-like combustion of the fuel, the piston releases the working connectors 16 again, thereby causing the combustion gases to relax and to flow away by way of the working connectors 16. The piston 2 is now accelerated further upward, drawing fresh air in through the working connectors 16, until it has reached its upper end position and the work cycle, as described, is repeated. The vibrations, particularly vertical vibrations, initiated as the result of these work cycles are absorbed by way of the vibration elements 6 and converted to heat energy. As a result the fuel tank 5 that is connected with the cylinder 1 is uncoupled by way of the vibration elements 6. In this way, the resonance effect of the fuel tank 5 is clearly reduced, thereby reducing the noise emissions of the diesel hammer pile driver.
Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 13192602.4 | Nov 2013 | EP | regional |
