GB1573020A

GB1573020A - Vibration generating device

Info

Publication number: GB1573020A
Application number: GB54145/76A
Authority: GB
Original assignee: Sjoeberg P A H
Current assignee: Sjoeberg P A H
Priority date: 1976-02-27
Filing date: 1976-12-24
Publication date: 1980-08-13
Also published as: BE851495A; AT354931B; FI770225A; AU2244777A; IT1077101B; DE2700394A1; ATA120077A; SE394400B; SU728700A3; DK85477A; AU513675B2; CH618356A5; ES456333A1; NO770243L; NL7701858A; FR2342105A1

Abstract

The rotor unit (10) is enclosed in a cylindrical chamber (9). This rotor unit has scoop-shaped recesses (22) around its circumference. An inlet (11) leads to the chamber (9) in order to allow a pressure medium directed at the scoop-like recesses to be introduced into the chamber. To ensure that the rotor unit (10) has an asymmetric distribution of mass, a number of holes (24) distributed asymmetrically around the axis of rotation are provided in this rotor unit. <IMAGE>

Description

(54) VIBRATION GENERATING DEVICE (71) We, NILS ERIC STRÖM of Keillersgatan 1 E, S-417 15 Göteborg, Sweden and PER ARNE HAKAN SJÖBERG of Smaragd vägen 58, S-440 31 Kode, Sweden, both Swedish citizens, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The present invention relates to a device for the generation of vibrations in load carrying surfaces.

When transportating certain materials such as wet sand, earth, concrete etc. very often difficulties arise because of the material adhering to the load supporting surfaces. In connection with by way of example load carrying vehicles such as trucks, buckets, tractor dumpers, concrete receptacles etc, time consuming and risky work using crow bars, shovels or similar is required in order to remove the remaining material residues after the unloading.

In connection with trucks this work involves great difficulties because material residues often adhere to those portions which in the tipping position of the loading platform are the least accessible ones, and as a rule one therefore omits to remove the last residues of material, which increase in volume during the transportation work. The result will be a gradual reduction of the carrying capacity of the vehicle, which increases the costs of transportation.

Corresponding problems exist in connection with by way of example buckets, where in practice it is unthinkable to clean the bucket by hand between each loading cycle.

A certain quantity of material can be loosened by striking the edges of the bucket against a hard object by means of the lifting mechanism, which, however, subjects the mechanism to a very unfavourable stress.

The gripping capacity of the bucket is also impaired by remaining material often adhering to the gripping edge of the bucket and to its underside.

In connection with concrete mixers or trucks with concrete receptacles also in addition to the drawbacks indicated above the problem arises that the remaining concrete fairly rapidly sets, whereafter it is a very time consuming and tedious undertaking to remove the material residues, all the more as the enclosed load surfaces often are difficult to get at for manual work.

When loosening material adhering to a surface it has earlier in different connections turned out to be advantageous, if said surface is subjected to vibrations. By way of example a vibrator mounted on the platform of a truck is shown in the German publication No. 2 054 398. The vibrations are produced by rotation of an unbalanced weight.

The present invention provides a device for generation of vibrations in load carrying surfaces on a load supporting device and comprising a rotor unit of comparatively great mass enclosed in a housing, said mass being unsymmetrically distributed round the axis of rotation of said rotor unit, in which the rotor unit is provided with a number of scoop like portions spaced round its periphery and is enclosed in a chamber, in which an inlet is arranged to direct a pressure medium introduced into the chamber through the inlet towards the scoop like portions, and from which chamber an outlet for the pressure medium leads, and wherein the housing is a solid piece of metal with a surface to be connected to the load carrying surfaces, and a main bore in the housing forming the chamber, which main bore forms seats for bearings, in which the two ends of the rotor unit are supported.

The invention will now be described more in detail in the following description relating to an embodiment, which is mounted on a truck. Reference is made to the accompanying drawings, in which the Figures 1 and 2 schematically illustrate the loading portion of a truck in tipping position provided with a vibrator device according to the invention Figure 3 is a cross-sectional view through the vibrator device along the line III-III in Figure 4, Figure 4 is a view of a longitudinal cross-section of the-vibrator device along the line IV-IV in Figure 3, Figure 5 is a corresponding side elevational view of the same, and Figure 6 is a coupling diagram showing the vibrator device coupled to the hydraulic system of a truck.

A vibrator device 1 according to the present invention and mounted on the underside of a load platform 2 of a truck 3 is illustrated in the figures 1 and 2, only the load supporting part of said truck being shown. In the example illustrated the vibrator device 1 is attached by means of screws close to the free end of the platform 2. In the example a position at a certain distance from the end of the platform close to the next outermost tie bar 4 of the frame of the load platform has been chosen. The location shall be chosen in each individual case in order to produce the greatest and most widely distributed vibrations all over the total platform surface. In addition to the chassis of the vehicle also the telescoping tipping device 5 for the load platform 2 is illustrated, said platform being in tipping position.The tipping device 5 in the example illustrated is of hydraulic type and forms part of a hydraulic system, to which also the vibrator device 1 according to the invention is connected via a feed line 6 and a return line 7. An example of the coupling of the vibrator unit 1 to the hydraulic system is described more in detail below with reference to Fig. 6. It is further evident from the figures 1 and 2 that the load platform 2 is pivotably connected with the chassis of the truck 3 at the rear end of the platform, and as an alternative said connection can possibly be made at the sides of the truck.

The design of the vibrator device according to the invention in an advantageous embodiment of the same is evident from the cross sectional views according to the figures 3 and 4. According to this embodiment the vibrator device 1 comprises a vibrator housing 8, made of a solid piece of steel or similar, and a rotor unit 10, which is rotatably journalled in the vibrator chamber 9.

There is further a feed inlet 11 and an outlet 12, which are in communication with the vibrator chamber 9, and which by means of nipples 13 are connected with a system of a pressure medium via the tubes 6, 7.

The vibrator housing 8 is in addition provided with a number of through bores 14 intended to receive screws, not shown, in order to anchor the vibrator device to the surface, which is to be subjected to vibration. At one end of the vibrator housing 8 a detachable end cover 15 is provided, which it attached to the housing body by means of a number of screws 16, an O-ring 17 securing the tight fit between the surfaces of the joint. At the opposite end a bore 18 is arranged, which is tightly closed by means of a nipple 19. The detachable end cover 15 and the bore 18, which can be opened, are necessary for the mounting and demounting of e.g. the rotor unit 10.

At each one of the ends of the vibrator housing 8 and directly in the bore that shapes the chamber 9 a ball bearing 20 is inserted, in which the rotor unit 10 is radially and axially journalled by means of a shaft journal 21 provided at each one of its ends.

The rotor unit 10 is by way of example made of a solid cylinder-shaped piece of steel or similar. In the surface of the rotor unit 10, right in front of the inlet 11 and the outlet 12, portions 22 of scooplike shape are provided, spaced around the periphery.

In the example illustrated these are formed by recesses which are for example obtained by a milling operation in the surface of the rotor unit 10. Such a recess has a bottom surface in the form of part of a cylinder whose axis extends in a direction substantially tangential to the surface of the rotor, at one end terminating in a crosswise arranged end wall substantially coinciding with an axial plane of the rotor unit 10, said end wall constituting a driving surface 23 intended to receive the driving power from a pressure medium conducted through the inlet 11.

In the illustrated example the rotor unit 10 is journalled in its center portion and exhibits an outer shape, which is symmetrical to the rotation, but it exhibits an asymmetrical distribution of mass, which is necessary for the generation of the vibrations. This has been brought about by a number of bores 24 in the rotor unit 10, which bores are axially directed and substantially collected in one half of the rotor unit, as seen with an imagined section by means of an axial plane.

As mentioned above, the inlet 11 is positioned right in front of the scoop like portions 22 of the rotor unit 10, the inlet being provided with a very much constricted inlet duct 25, which is extending substantially in tangential direction to the surface of the rotor unit, and which leads into the cylindrical surface of the vibration chamber 9 as an orifice 26, which is inclined relative to the longitudinal direction of the inlet duct 25. The inclined position of the orifice arises because the inlet duct 25 leads almost tan gentially into the wall of the cylindrical vibration chamber 9. The outlet 12 provides an orifice 27 in the vibration chamber 9 which has an area which considerably ex ceeds the area of the orifice 26 of the inlet duct 25 and extends with an undiminished cross sectional area through the vibration housing 8 to the nipple 13.

From the figure 6 it is evident that the vibration device according to the invention can be connected to the hydraulic system of the truck, which among other things provides the tipping movement of the load platform 2. A receptacle 28 for hydraulic fluid, a pressure pump 29 connected to said receptacle, and a three way valve 30 normally form part of the hydraulic system, said valve 30 permitting the optional connection of the pressure pump 29 to a cylinder/piston unit 31 forming part of the tipping device in order to carry out the tipping movements, to disconnect said connection in order to maintain a certain tipping position, or to establish a connection between the cylinder/piston unit and the receptacle 28 of hydraulic fluid via a return duct 32 in order to bring about the lowering of the loading platform.In the example illustrated an additional three way valve 33 has been introduced in the system between said three way valve 30 and the pressure pump 29, which valve 33 via the supply duct 6 is in communication with the inlet of the vibration device 1. The return flow duct 7 from its outlet 12 leads to the receptacle 28 of hydraulic fluid. The three way valve 33 is intended alternatively to supply hydraulic fluid under pressure from the pressure pump 29 to the tipping device with the cylinder/piston unit 31 (the position illustrated) or after a change-over supply hydraulic fluid under pressure to the vibration device 1 via the supply duct 6.

The vibration device 1 according to the invention thus is intended to be operated by means of a pressure medium such as a hydraulic fluid or similar. As mentioned above the loading platform of the truck is tipped by means of the tipping device and by the two three way valves 30, 33 in the positions showed in figure 6. When the desired tipping position has been reached, the threeway valve 30 is changed over to such a position that all communication with the interior of the cylinder/piston unit 31 is disconnected. In order to loosen possibly adhering material from the load supporting surfaces of the loading platform and also in other respects bring down the time required for a complete emptying of the load platform, the vibration device 1 according to the invention is started.To this effect the three way valve 33 is changed-over a quarter revolution in clockwise direction, whereby the pressure pump 29 supplies hydraulic fluid to the vibration device 1 via the supply duct 6 and via the return flow duct 7 leads the fluid back to the receptacle 28 for hydraulic fluid. Hydraulic fluid, which by means of the pressure pump 29 is brought to circulate in the hydraulic system under high pressure obtains a considerable increase of the speed of flow in the constructed inlet duct 25 on account of the very much reduced area of the inlet 11 of said duct.By this high speed the hydraulic fluid through the orifice 26 serving as nozzle is spread in an advantageously calculated direction because of the inclined position of the orifice, so that the rotor unit 10 is brought to rotate with great speed due to the pressure and kinetic energy of the fluid, which energy is transmitted to the rotor unit via the crosswise positioned driving surfaces 23 of the scoop like portions 22.

The rotor unit 10 is thus brought to rotate according to the same principles as a turbine, and as in a turbine the pressure medium obtains a strong acceleration with a pressure drop after passing the orifice 26 because of the greater volume of the vibrator chamber 9 and the outlet 12. By the unsymmetrical distribution of mass of the rotor unit 10 a strong unbalance is thereby created in the same, which results in vibrations, the frequency of which are dependent upon the number of revolutions of the rotor unit, said vibrations being transmitted to the load supporting surfaces of the load platform because of the fact that the vibration device 1 is rigidly connected with said platform.The vibration device 1 is stopped by changing over the three way valve 33 to the position illustrated in figure 6, while the load platform is lowered down by changing over the three way valve 30 in such a way that the interior of the cylinder/piston unit 31 is brought in communication with the return duct 32 and the receptacle 28 of hydraulic fluid. If during the operation of the pump 29 both the valves 30, 33 are closed the delivered hydraulic fluid is conducted to the receptacle 28.

The invention is not limited to the example of embodiment described above and illustrated in the drawings, but can be varied within the scope of the following claims. By way of example the location of the vibration device can be chosen in a different way for different applications, it also being possible to use more than one vibrator in one and the same installation. It can also be imagined that the vibration device is mounted in connection with such installations, for example concrete mixers, where a separate hydraulic system is arranged for the vibration device. Also other types of pressure medium can be used, for example compressed air. The vibration device can to advantage be controlled from the driver's cabin of a vehicle, such an arrangement for example being provided by means of solenoid operated valves.Also the design of the vibration device can be made in different manners, the rotor unit 10 for example can be given a different design with by way of example one bucket wheel in combination with unbalanced weights. In the foregoing a rigid mode of mounting has been indicated.

In certain applications, however, some form of elastic element between the load supporting surface and the vibration unit can be of advantage.

However, the illustrated and described embodiment is very advantageous for the intended service. Under operating conditions the vibration device will be subjected to very great stresses, for one thing on account of the vibrations, which the device itself is generating, and for another thing on account of trucks and other load carrying means as a rule being subjected to great stresses as a consequence of blows, knocks and other mechanical stresses, and also because of humid and wet climatic conditions and great changes of temperature However, because of the fact that the vibrator housing is built as a unit from one single piece of material, and that it can be attached directly to the load supporting sur face, a great rigidity offering resistance to stresses from the outside is obtained.The rotor unit is likewise of a heavy design made from one single piece of material, its jour nalling being arranged directly in the bore of the rotor housing, thus not in any end walls or similar fastened by means of screws, as such elements can get displaced or loosen on account of the vibrations. The elongated shape of the rotor exhibiting a great distance between the journalling points produces good bearing conditions with a long length of life of the bearings.

WHAT WE CLAIM IS: 1. Device for generation of vibrations in load carrying surfaces on a load supporting device and comprising a rotor unit of comparatively great mass enclosed in a housing, said mass being unsymmetrically distributed round the axis of rotation of said rotor unit, in which the rotor unit is provided with a number of scoop like portions spaced round its periphery and is enclosed in a chamber, in which an inlet is arranged to direct a pressure medium introduced into the chamber through the inlet towards the scoop like portions, and from which chamber an outlet for the pressure medium leads, and wherein the housing is a solid piece of metal with a surface to be connected to the load carrying surfaces, and a main bore in the housing forming the chamber, which main bore forms seats for bearings, in which the two ends of the rotor unit are supported.

2. A device according to claim 1 in which the main bore is substantially cylindrical.

3. Vibration device according to claim 1 or claim 2, in which the rotor unit is substantially of cylindrical shape and forms a solid unit, the unsymmetrical distribution of the mass thereof being provided by a number of bores unsymmetrically distributed round the axis of rotation and extending in axial direction from the ends of the unit towards its middle portion.

4. Vibration device according to any one of claims 1 to 3 in which the scoop like portions comprise recesses each in the form of a part of a cylinder whose axis extends substantially in a direction tangential to the surface of the rotor unit, each recess having a crosswise positioned driving surface intended to receive the pressure medium.

5. Vibration device according to any one of claims 1 to 4 in which the housing is provided with inlet and outlet bores, which extend substantially in tangential direction to the main bore, the inlet to the main bore being of smaller cross section than the outlet therefrom, the orifice by which the inlet is lead into the main bore being inclined relative to the longitudinal direction of the inlet.

6. Vibration generating device substantially as herein described with reference to and as shown in the accompanying drawings.

7. Load-carrying apparatus including one or more vibration generating devices according to any one of the preceding

Claims

claims.

8. Bulk material transporting vehicle including one or more vibration generating devices according to any one of claims 1 to 6.