US 3583497 A
Description (OCR text may contain errors)
United States Patent Inventors Bohdan Kossowski Sopot, Chopina 9; Czeslaw Gawlik, Gdynia ul. Gvottgeva 42 m 2; Adam Hlibowicki, Sopot ul. Ahrahama 28a m 15, all of, Poland;
Appl. No. 786,302 Filed Dec. 23,1968 Patented June 8, 1971 Priority Dec. 29, 1967 Poland 124410 AN IMPROVED VIBRATING POWER HAMMER FOR DRIVING AND EXTRACTING PILES 5 Claims, 5 Drawing Figs.
US. Cl 173/49, 74/61 Int. Cl. E02d 7/18 Field of Search 173/49; 74/61 Primary Examiner Ernest R. Purser Attorney-Stevens, Davis, Miller and Mosher ABSTRACT: A vibrating power hammer having a vibrator consisting of rotatable eccentrics mounted on a pile casing. Motors are provided to positively rotate the eccentrics in opposite directions. The motors are mounted to be isolated from the. vibration of the vibrator in a substantially constant position with respect thereto.
PATENTEU JUN 8197! SHEET 1 0F 2 AN IMPROVED VIBRATING POWER HAMMER FOR DRIVING AND EXTRACTING FILES DISCLOSURE The present invention relates to a vibrating hammer for driving and extracting piles, casing pipes and the like, said casing pipes being moulds for construction reinforced concrete piles.
Moulding of piles requires vibrating hammer of a greater power than, for example, for driving piles or pipes into or drawing them out of the ground.
Vibrohammers of great power are provided with vibration exciters, vibrators furnished with an arrangement of enlarged unbalanced weights and hereinafter referred to as the eccentrics." These enlarged unbalanced weights are mounted on two shafts driven by at least one motor, and they are, in particular, arranged at the ends of shafts and may be transposed within a plane.
In order to secure the most advantageous conditions to fill a casing pipe with concrete and introduce the reinforcement into said concrete, the vibrohammers are constructed in the following manner: their vibrator is mounted on a cylinder, into which the casing pipe is introduced, or the vibrator is directly mounted on a casing pipe provided with two stops, which the vibrator hammer strikes against, whereby the shafts bearing the eccentrics are mounted on the hammer and located outside the diameter of the cylinder or pipe.
The hitherto known vibrohammers have several defects and disadvantages, which make their operation more difficult and lengthen the period of pile moulding.
All the hitherto known vibrohammers commonly have great overall dimensions, since the location of eccentrics on shafts arranged at both sides of the casing pipe makes it necessary to considerably enlarge the vibrator mechanism.
Driving motors for the vibrohammers are secured against vibration by means of resilient connectors such as springs or rubber inserts in which connection the arrangement of belt transmission tension means causes the vibrohammers to be of a complicated structure. However, a toothed gear forming a rigid connection between the driving motors and the vibrators did not give satisfactory results, because the driving motors were exposed to vibration and were often damaged. The known vibrohammers having eccentrics mounted at the shaft ends of two driving motors are of a heavy structure and, in addition, they deteriorate, since they are provided with two additional arrangements of toothed wheels synchronizing the motors, said toothed wheels being rigidly connected with the toothed wheels of the driving motors. Driving motors of said vibrohammers are immovably connected with the vibrator body and they are not insulated from the vibration, which circumstance has a disadvantageous bearing upon the life of the motor bearings.
The known vibrohammers mounted on a cylinder or casing pipe have a common disadvantage, namely, they are mounted in a sliding manner which requires an exact production with regard to the friction elements, a large amount of lubrication and a special protection against impurities. A special trouble in the production of vibrohammers is to achieve an effective protection of the driving motors against shocks caused by the vibration exciter and intensified by its strokes against the anvil, whereby the toothed gear transferring the motor turns to the eccentric sets is especially sensitive to shocks. The technical advantages from applying a toothed gear, like diminution of the vibrohammer dimensions and reduction of its weight, are outweighed by frequent damages of the toothed wheels.
The aim of the present invention is to eliminate these disadvantages while achieving a diminution of the vibrohammer dimension providing an efi'ective shock absorption of the driving motors and extending the life of the toothed driving wheels by construction of a set of eccentrics and a transmission for driving the toothed wheels in synchronization by embedding the eccentrics in the vibrator, and by protection of the driving motors against vibration.
The vibrohammer according to the invention has a vibrator which consists of two sets of eccentrics mounted on pins seated in the beater and coupled with one another by means of toothed wheels fixed to the eccentrics, which are simultaneously driven by two driving motors through toothed driving wheels mounted at both ends of the shafts of said motors, said driving motors being fastened to the beater by means of rockers and shock absorbing connectors in such a way that they are able to move along a radius equal to the distance between the axes of the toothed wheels fastened to the motors and the toothed wheels of the eccentrics.
A further feature of the inventive vibrohammer is that the vibrator beater is seated on a cylinder or casing pipe by means of guide reels and is kept in a determined and invariable position in a perpendicular plane in relation to the longitudinal axis of the casing pipe or of another element being driven into or drawn out of the ground.
The technical effect of mounting eccentrics on pins fastened to a beater and coupling two eccentric sets by toothed wheels driven by two motors results in a considerable diminution of the overall dimensions of the vibrohammer in question, since such a construction enables the eccentrics of a set to be mounted close to each other independently from the cylinder or casing pipe diameter, and secures a complete synchronization of driving motors, said synchronization being very important in multishaft sets of vibrators.
Each pin of the present invention is permanently loaded in one direction in contradistinction to a shaft about which the load rotates during the working cycle. In calculating the pin diameter one must take into account the fact that the allowable stress is unilaterally variable. The diameter of a shaft has to correspond to a bilaterally variable stress taking into account both the eccentric exciting force and the impulse at the blow moment. The diameter of a pin is smaller than that ofa shaft under identical load circumstances, which, in consequence, causes the overall dimensions of bearings, eccentric hubs, etc. to also be smaller.
In consequence of mounting the motors on the vibrator beater by means of rocker arms and absorbing connectors, the motors are protected against the vertical motions of the aforesaid beater and the mashing of toothed wheels of the driving motor with the toothed wheels coupling the eccentrics into two sets is resilient and substantially constant. Due to such an arrangement the driving motors, provided with adequately chosen resilient connectors, are held in substantially constant position in relation to the beater moving up and down, whereby the resiliency and equal meshing of toothed wheels are secured by rocker arms. The ends of the rocker arms fastened to the beater move up and down, and the other ends fixed to the motor hold this motor in a constant position.
The mounting of the vibrator mechanism together with driving motors on a beater seated on a cylinder or casing pipe by means of guide reels results in an additional effect, namely, the beater is correctly guided along the cylinder or casing pipe without any need of accurate fitting. In addition, an adequately chosen clearance between reels and cylinder or casing pipe enables the vibrator to move without using rolls, when it operates in a vertical position, which reduces the resistance to motion and the abrasive wear of elements, since the guiding operation takes place only when the vibrohammer operates in a position which is deflected in relation to the vertical.
The present invention will now be described, by way of nonlimiting example, with reference to the accompanying drawings wherein:
FIG. 1 is a front view, partially in section, of the vibrohammer seated on a casing pipe;
FIG. 2 is a schematic perspective of the power transmission and eccentric system of the vibrohammer;
FIG. 3 is a partial front view of the device holding the vibrator beater in position;
FIG. 4 is a transverse section of the vibrator beater taken along line A-A in FIG. 1; and
FIG. 5 is a transverse section similar to FIG. 4 showing said seating arranged to hold the beater in the plane perpendicular to the longitudinal axis ofa casing pipe.
FIGS. ll and 2 show the vibrohammer which consists of vibrator l seated on casing pipe 2, lower stop 3 and upper stop 3a, both of which are mounted on the pipe, and arrangement 4 is affixed to the vibrator by means of springs. The arrangement 4 has been shown in a diagrammatic manner since it is well known and is not the subject of the present invention.
Vibrator 1 consists of beater 6 having two eccentric sets '7 and 7a rotationally mounted on pins 3 fastened to the beater and coupled with one another by means of toothed wheels 9 and 9a.
Eccentrics 7 and 711 can also be fastened to toothed wheels 9 and 9a mounted rotationally on pins 8, or indeed, the eccentries and toothed wheels can be integral, for example, toothed wheels with risers. The eccentric sets are driven by driving motors Ml by means of toothed driving wheels tll secured at both ends of the driving motor shafts. The motors rotate in opposite directions thus rotating the eccentric sets in opposite directions, their rotation being synchronized due to being coupled by means of toothed wheels, which secured an invariable in-phase rotation of the eccentrics.
H6. 2 shows the mutual position of eccentrics adapted for putting the vibrator in motion along the longitudinal axis of a casing pipe. This position can be changed at will by an angular shift at the eccentrics which causes a periodically variable torque to come into existence. A change of the eccentric posi tion can be achieved by alteration of the mounting of the eccentrics on the toothed wheels or by an adequate coupling of the toothed wheels then e.g. said eccentrics and toothed wheels are an inseparable whole.
Driving motors it) are suspended on beater 6 by help of rocker arms 12 and absorbing connectors 13 having the form of springs, rubber inserts or pneumatic shock absorbers, which protect the vibrating beater from the engine motions. The length of these rocker arms is selected for a correct distance between the axes of the meshing toothed wheels ill, 9 and 9a which are mounted on axes relatively movable with regard to one another.
Due to such an arrangement, the driving motors are protected from the-beater motions performed in a vertical plane. In addition, the toothed driving wheels lll keep the interaxial distance constant and thus they secure a correct meshing with toothed wheels 9 and 9a independently from the position of said wheels, said position being periodically variable as a result of the aforesaid beater motions.
As it has been shown in FIG. 3, the vibrator beater 6 is provided with a device keeping it in an invariable position in a perpendicular plane towards the longitudinal axis of casing pipe 2. This device consists of roll M mounted on beater 6 and of guides 15 seated on stops 3 and 3a or on casing pipe 2.
The device can be constructed by other means; for example, it can consist of a few rolls and guides which can be mounted with the guides mounted on beater 6 and roll M or a few rolls seated on the casing pipe or on stops 3 and 3a.
A free shaft of vibrator ll along casing pipe 2 is secured by seating its beater 6 on said pipe by means of guiding rolls to and 36a shown in FIGS. 3 and 5, respectively.
The vibrator beater can be kept in constant position in the perpendicular plane towards the longitudinal axis of the casing pipe by help of guiding rolls M by giving their rims an adequate profile, for example, with flanges 16a, which flanges enclose strips 17 fastened to cylinder or casing pipe 2, or rolls with spherical profile and guided along adequately shaped positioned on the ground and ropes 119 are fastened to support plates 20. As the vibrator ll approaches the lower stop 3 and begins with beater 6 to strike upon said stop, the casing pipe is driven into the ground. After the pipe has been driven into the ground, the vibrator, owing to a light support by the ropes,
loses its contact with stop 3 and becomes a normal vibrator, the vibrations of which can be utilized to condense the concrete mix introduced into the casing pipe. A stronger support by ropes t9 causes the vibrator l to approach the upper stop 3a, whereby the vibrator begins to strike upon this upper stop with beater 6, as a result of which the casing pipe is drawn out of the ground to strip the casing pipe from the concrete pile.
The vibrohammer according to the present invention can be also constructed in other embodiments, in particular, the vibrator can be seated on a cylinder provided with both lower and upper stops, into which cylinder is introduced a casing pipe, said vibrohammer being mounted on said pipe by help of a holder. A vibrohammer of such construction can be utilized to perform some other operations such as driving into and drawing out of the ground various elements.
ll. A vibrating power hammer device for forming piles in casing pipes and the like and driving them into and extracting them from the ground comprising a vibrator having spaced upper and lower stops, means to fixedly mount said stops on said pile, a beater movably mounted between said stops, two subassemblies of counterrotating eccentrics mounted on said beater to impart thereto vibrating motion against one of said stops thus causing said driving and extraction of the pile, means for controlling the direction of impacts of the beater, each said eccentric subassembly comprising a drive motor having a drive shaft, two eccentrics pivotally mounted on said heater, driving gear means mounted on both ends of said drive shaft and coupled to said eccentrics, and damping means for suspending said motor on the beater in such manner as to be able to move along a radius equal to said driving gears thus maintaining a fixed interaxis distance in the course of relative motion of the beater with respect to the drive motor.
2. A vibrating power hammer device according to claim t further comprising guiding means comprising rollers and guides mounted between said beater and said pile allowing free motion of said beater along the longitudinal axis of the pile while preventing torsional movements thereof.
3. A vibrating power hammer device according to claim 1 wherein said driving gears are toothed gears integral with said eccentrics.
4. A vibrating power hammer device according to claim ll further comprising at least one roller and a corresponding number of guides for said roller mounted between said stops, casing pipe and beater for maintaining said beater in a plane perpendicular to the longitudinal axis of said pile.
5. A vibrating power hammer device according to claim It further comprising means to suspend said device from a crane or the like, the tensioning of said suspension means controlling the selection of stops to be struck by said beater.