Patent Application
20150129271
Applicant claims priority under 35 U.S.C. §119 of European Application No. 13 192 600.8 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 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, whereby the expanding combustion gases flow out of the working connectors and subsequently fresh air is drawn into the combustion chamber by means of the piston, which continues to rise upward. 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 resulting 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. With the invention, a diesel hammer pile driver of the aforementioned type is created, in which the noise emission 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 combination chamber is provided. The combination 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. By means of this device, a predetermined amount of fuel can be introduced into the combustion chamber during each working cycle. At least two working connectors are disposed to pass through the circumference wall of the cylinder. At least one working cylinder is provided with a muffler device.
With the invention, a diesel hammer pile driver of the aforementioned type is made available, the noise emission of which is reduced. Because at least one working connector is provided with a muffler device, the noise emissions initiated by the expansion of the combustion gases are clearly reduced.
In a further development of the invention, the at least two working connectors are disposed on two imaginary horizontal planes, vertically spaced apart from one another, so that at least one working connector is disposed vertically offset relative to a second working connector, whereby the at least one lower working connector disposed on the lower plane is provided with a muffler device. When the piston is accelerated upward, it first releases the lower working connector, after which the exhaust gases escape through the muffler. Subsequently, the vertically offset second working connector is released, thereby making it possible to draw fresh air into the combustion chamber.
Preferably, the at least one upper working connector disposed on the upper plane does not have a muffler apparatus. In this way, unhindered flow of fresh air into the combustion chamber is achieved. In this way, entrainment of dirt particles possibly adhering in a muffler that might be provided, into the combustion chamber, is prevented.
In a further embodiment of the invention, the two planes are spaced apart from one another by between 80 millimeters and 120 millimeters, preferably between 95 millimeters and 115 millimeters. It has been shown that in this way, an optimal displacement distance of the upwardly moving piston is achieved, in which the combustion gases escape from the lower working connector, provided with a muffler device, before the upper working connectors are released, thereby causing fresh air to be drawn into the combustion chamber.
In a further development of the invention, the muffler device is formed by a mantled perforated pipe. In this way, a simple and, at the same time, effective absorber muffler is formed, which is not susceptible to contamination by combustion gases.
In a further embodiment of the invention, the muffler device is attached to the cylinder, elastically mounted by way of vibration elements. In this way, uncoupling of the muffler device relative to the cylinder is achieved, thereby further reducing noise emissions. Preferably, the vibration elements are configured as elastomer components or rubber components. In a further embodiment, a strike hood for accommodating the material to be pile-driven is disposed below the striker. The striker is disposed, at least in certain regions, so as to surround a sound absorption element. In this way, damping of the noise emissions that occur when the striker impacts the strike hood is brought about.
In a further development of the invention, the sound absorption element is formed from at least one perforated sheet-metal cassette filled with an absorber material. In this way, a robust and shock-resistant sound absorption element is brought about. In this connection, the absorber material is preferably formed from mineral insulation wool, melanin resin foam or another suitable porous material.
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 45.
The fuel pump 41 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 circumference wall of the cylinder 1 has two working connectors 16, 17 shown in
In this connection, the working connectors 16, 17 are disposed on two imaginary horizontal planes Eu and Eo disposed vertically at a distance from one another, whereby the lower working connector 16, disposed on the lower plane Eu, is disposed on the opposite side of the upper working connector 17, disposed on the upper plane Eo, passing through the cylinder 1. The lower working connector 16 is provided with a muffler device 5.
The muffler device 5 is essentially formed by a perforated pipe 51 provided with a connector pipe piece 52, which pipe is disposed centered in a cylindrically configured mantling 53. See
The muffler device 5 is attached to the cylinder 1 by way of two holding arms 56 disposed at a distance from one another. Vibration elements 57 are disposed between the holding arms 56 and the mantling 53 of the muffler device 5, thereby bringing about uncoupling of the muffler device 5 from the cylinder 1, to a great extent. The connector pipe piece 52 of the muffler device 5 opens into the lower working connector 16 of the cylinder 1. In the exemplary embodiment, the lower working connector 16 is disposed vertically offset from the upper working connector 17 by 105 millimeters.
In order to raise the piston 2 for the first time, to start the diesel hammer pile driver, the mass section 22 of the piston 2 has an undercut that forms an entrainment shoulder—not shown—for engagement of a driver of a disengagement apparatus—not shown.
In the exemplary embodiment, a strike hood 6 for accommodating a material 81 to be pile-driven is disposed underneath the striker 3 of the diesel hammer pile driver. See
With the impacts of the piston 2 on the striker 3, a force directed downward is exerted on the striker 3 and, by way of the striker 3, onto the strike hood 6 that accommodates the material 81 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 first releases the lower working connector 16, thereby causing the combustion gases to relax and to escape from the working connector 16 by way of the muffler device 5. After the upper working connector 17 is released, fresh air is drawn in by the piston 2 that is further accelerated upward, until the piston 2 has reached its upper end position and the work cycle, as described, is repeated. Because the fresh air can flow in through the upper working connector 17, which is not provided with a muffler device, without hindrance, only very slight suction through the lower working connector 16 that is provided with the muffler device 5 takes place, thereby preventing renewed introduction of dirt particles from the escaping combustion gases.
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 |
|---|---|---|---|
| 13192600.8 | Nov 2013 | EP | regional |
