Road structure – process – or apparatus – Apparatus – Tamper
Reexamination Certificate
1999-06-30
2001-09-25
Will, Thomas B. (Department: 3673)
Road structure, process, or apparatus
Apparatus
Tamper
C404S133050
Reexamination Certificate
active
06293729
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Related Art
The invention relates to a tamping appliance for ground compaction, capable of being manually guided by means of a guide fork or the like and having a tamping or beating working mass driven linearly back and forth by an internal combustion engine via a crank mechanism and a spring assembly.
2. Discussion of the Related Art
Tamping appliances of this type, which are supported on the ground solely by means of the tamping butt, are guided in the desired direction by an operator as a result of the direct transmission of guiding forces by means of a guide fork, or, for example, a drawbar, during the oscillating movement of the tamping butt. When the drive is switched off, the appliance is difficult to transport, and it has to be carried or moved by means of a suitable device, such as, for example, a handcart.
On account of manual operation, the weight of such appliances is restricted, and therefore, for example, equipping them with relatively heavy diesel engines creates difficulties.
OBJECTS AND SUMMARY OF THE INVENTION
The object on which the innovation is based is to design a tamping appliance of the type initially mentioned, in such a way that handling becomes substantially easier, in particular the physical strength required for guiding it is reduced and it is possible, at any time, to change the location of the tamper in a simple way, when it is switched off, without any auxiliary devices.
This object is achieved in that the tamping appliance is additionally supported against the ground via an at least single-axle traveling gear
By means of the traveling gear, the tamper can easily be moved without additional aids, even when the tamper drive is switched off. When the tamper is in operation, the guiding forces required are appreciably reduced on account of the rolling support of substantial weight components of the appliance. Moreover, there is the possibility of increasing the overall weight of the tamper beyond the limit hitherto considered acceptable and, for example, to provide the tamper with a heavy diesel engine.
A highly advantageous embodiment provides for the additional traveling gear to carry the internal combustion engine.
In another highly advantageous embodiment, the traveling gear is provided with its own drive, a common power source preferably being provided for generating the tamping movement and for driving the traveling gear. The traveling gear's own drive may advantageously be designed as a hydraulic drive or take place via a driving chain. The traveling gear drive can expediently be changed over between forward motion and reverse motion.
In order to ensure that the tamper, when switched off, is always in a stable position, the traveling gear may advantageously be designed as a three-point traveling gear by means of an additional supporting wheel on that side of the tamping butt which faces away from the driveable axle.
In order to keep as low as possible any wear of the traveling gear under the influence of the vibrations which are generated by the tamper and pass through the traveling gear, it is highly advantageous to stabilize the tamper upper mass connected to the traveling gear, that is to say to keep the movement of said upper mass as low as possible while the tamper is in operation.
Known manually guided tamping appliances are designed in such a way that the upper mass comprises approximately two thirds and the beating working mass or lower mass one third of the entire tamper mass, whilst the excursions covered in each case by the upper mass and the working mass are in inverse proportion to one another. Here, the upper mass moves in the order of magnitude of 25 to 30 mm.
This movement of the upper mass at a frequency of 10-11 Hz has many adverse effects, not only because these vibrations are transmitted to the body of the person guiding the working appliance via a guide fork, in particular to the hand and arm, but also because high loads are exerted on the mounted drive engine, irrespective of its design and, likewise, irrespective of the traveling gear which is provided according to the invention.
The output of the tamping system is largely dependent on the upper mass, since too large a working mass or too high a speed of the working mass moves the upper mass overdimensionally and aggravates the problems described above.
Although these harmful effects could, in part, be limited by a substantial increase in the upper mass, this would greatly increase the overall weight of the tamper, thus not only raising the power requirement of the drive engine, but also nullifying the benefit achieved by the traveling gear in making it easier to operate the tamper.
In order to stabilize the upper mass, without an appreciable increase in the weight of the appliance, and thereby lengthen its life, further improve its handling and protect the operator more effectively against the harmful effects of the vibrations, in a particularly advantageous embodiment of the appliance according to the invention the latter is provided, in the region of the upper mass, with a countermass capable of being driven by the engine jointly with the working mass, but in the opposite direction to the movement of the working mass.
The upper mass is pressed upward by a crank mechanism self-supported on its case at the moment when said crank mechanism, via its connecting rod, a guide piston and a spring assembly, presses the working mass, and consequently the tamping butt, downward. The result of the spring assembly is that, during the downward movement of the guide piston, first these springs are tensioned, at the same time absorbing energy, whereupon, with a delay induced thereby, they subsequently release the stored energy again for the downward movement of the tamping butt. This delay must be taken into account when the movement of the countermass is coordinated with the movement of the working mass. When the working mass is drawn upward again by the crankpin of the crank mechanism, the upper mass is moved downward.
For this purpose, in an advantageous embodiment, the drive of the countermass is derived from the crank mechanism, and the movement of the spring assembly end connected to the crank mechanism and the movement of the countermass are offset relative to one another with respect to the crank angle, by 180° minus a phase shift derived from the design parameters of the spring assembly.
When the spring assembly end connected to the crank mechanism exceeds the lower end point of its linear movement, the energy stored until then in the spring assembly is released as tamping or beating energy, so that only at this moment is the countermovement of the countermass required in order to damp the movement of the upper mass, or, in other words: the movement of the countermass to top dead center is to take place only when the spring assembly end connected to the crank mechanism has already reached bottom dead center. This is achieved by means of the above-described phase shift which, in practice, must be coordinated at least approximately with the design parameters.
According to an expedient embodiment, the countermass is guided on the upper mass in parallel with the direction of movement of the working mass. At the same time, in an advantageous embodiment, the countermass is driven by a compensating eccentric on the crank mechanism, specifically, for example, via a connecting rod. According to another expedient embodiment, the connection between the countermass and the compensating eccentric may be designed as a slider crank.
According to another expedient variant, the countermass consists of two part masses arranged in each case on one side of the crank mechanism or the other, at approximately the same height with respect to the axis of rotation of the crank mechanism, and each part mass is driven by an eccentric pin on an eccentric disk assigned to said part mass and rotatably coupled to the crank mechanism, the connection between the eccentric pin and the associated part mass being designed in each case as a slider crank.
In ano
Boyle Fredrickson Newholm Stein & Gratz S.C.
Hartmann Gary S.
Wacker-Werker GmbH & Co. KG
Will Thomas B.
LandOfFree
Compactor for compacting soil does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compactor for compacting soil, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compactor for compacting soil will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2514825