GB2414780A

GB2414780A - A drum unit for vibrating rollers intended for single arm assembly

Info

Publication number: GB2414780A
Application number: GB0508777A
Authority: GB
Inventors: Tyra Lycken; Tomas Rommer; Madeleine Westerholm
Original assignee: Dynapac Compaction Equipment AB
Current assignee: Dynapac Compaction Equipment AB
Priority date: 2004-06-04
Filing date: 2005-04-29
Publication date: 2005-12-07
Also published as: DE102005019240B4; SE0401435D0; SE0401435L; GB0508777D0; DE102005019240A1; SE527279C2

Abstract

A drum unit 2 for single arm assembly on a vibrating roller 1 via a single arm 3, comprising a drum 4, an eccentric unit 6, a transmission shaft 7 for the driving of the eccentric unit 6, a drum motor 8 with integrated drum bearing and internal clearance for the transmission shaft 7, a vibration motor 9 rigidly connected to the drum motor 8 and driving eccentric unit 6 via the transmission shaft 7, and a number of sets of elastic members 10, arranged so that their points of cooperation 11 coincide with a plane 16 at right angles to the centre line 12 of the drum 4. The drum motor 8 is rigidly connected to the drum 4 and elastically connected, via the sets of elastic members 10 to the single arm 3 and the plane 16 not coinciding with the centre of gravity TP of the vibrating mass.

Description

24 1 4780

DESCRIPTION

Drum Unit for Vibrating Rollers Intended for Single Arm Assembly s This invention relates to a drum unit intended for single arm assembly on a vibrating roller. The purpose is to achieve single arm assembly where the unit's drum motor is rigidly connected to the unit's drum. The drum unit is particularly suitable for use on vibrating rollers for vibration compaction of unbound and bound layers of stone, gravel, macadam and asphalt.

A vibrating roller drum is normally connected to the roller via elastic members.

The members are primarily symmetrically arranged on both sides of the drum's centre of gravity and connected with a fork on both sides of the roller. The fork's necessary extension, outside the drum heads, makes compaction more difficult close to walls, tunnel walls and other high obstacles. Roller manufacturers have therefore developed rollers that have at least one roller assembled on a single arm and slightly displaced laterally. This makes it possible to compact close to high obstacles on one side of the roller. However, single arm assembly requires new solutions as regards attaching the elastic members.

Roller manufacturers have solved the problem by arranging the elastic members closer to the drum's centre of gravity, although still on both sides of this. This arrangement means that it is easier to reach the far members and attach these, as well as the nearest members at one end of the drum motor. The drum motor, which both rotates the drum and comprises the drum bearing, is rigidly attached at its other end in the roller's single arm. The drum motor consequently constitutes a spacer between the centre of the drum and the single arm. The arrangement means that the extent of the single arm inside the drum can be limited. A vibration motor is rigidly connected to the drum motor and, via a cardan shaft, drives an eccentric unit that causes the drum to vibrate. In the known arrangement, the choice of drive shaft type is constrained by the necessity for this to allow angular changes in order to follow the various movements of the drum. The drum motor includes a clearance in its centre for the cardan shaft. The cardan shaft's joints take up space and require the clearance to have a large diameter. This means that drum motors with normal clearance diameters cannot be used, but must be specially manufactured in small runs. There is a considerable risk of the cardan shaft's components being under-dimensioned in an endeavour to minimize their dimensions. The cardan shaft is also difficult to access for inspection, maintenance and repairs.

The purpose of this invention is, in accordance with the patent claims, to achieve a drum unit where the drum motor is rigidly connected to the drum and follows its movements. The vibration motor that is rigidly connected to the drum motor can then power the eccentric unit via a rigid transmission shaft, which is entirely maintenance-free and requires a significantly smaller clearance diameter in the drum motor than a cardan shaft. This arrangement is possible by departing from the previously known principle regarding the elastic members' primarily symmetric distribution around the drum's centre of gravity. The elastic members are instead arranged on the same side of, and displaced from, the drum's centre of gravity. Following its own practical trials, the applicant has experienced that a drum unit achieves the intended and optimal function when its elastic members are displaced in accordance with this application's patent claims.

In accordance with the present invention there is provided a drum unit for single arm assembly on a vibrating roller via a single arm, comprising a drum, an eccentric unit, a transmission shaft for the driving of the eccentric unit, a drum motor with integrated drum bearing and internal clearance for the transmission shaft, a vibration motor rigidly connected to the drum motor and driving the eccentric unit via the transmission shaft, and a number of sets of elastic members, arranged so that their points of co-operation coincide with a plane at right angles to the centre line of the drum, wherein the drum motor is rigidly connected to the drum and elastically connected, via the sets of elastic members to the single arm and wherein said plane does not coincide with the centre of gravity of the vibrating mass.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of a vibrating roller that comprises a drum unit for single arm assembly in accordance with the present invention; Figure 2 is a top view of the vibrating roller from figure 1; Figure 3 is a vertical crosssection of a previously known drum unit for single arm assembly; Figure 4 is a vertical cross-section of a preferred first version of a drum unit for single arm assembly in accordance with the present invention, Figure 5 shows the drum unit from figure 4 from the right, schematically reproduced; Figure 6 is a vertical cross-section of a second version of a drum unit for single arm assembly in accordance with the present invention; and Figure 7 shows the drum unit from figure 6 from the right, schematically reproduced.

Figure I shows a vibrating roller 1. At the rear it is supplied with a dual arm assembled drum, and at the front it has a drum unit for single arm assembly 2 in accordance with this invention. The drum unit 2 is connected to the vibrating roller l via a single arm 3.

Figure 2 shows the vibrating roller I from above, the drum unit 2 and its drum 4.

The drum 4 is displaced laterally so that the drum head constitutes the vibrating roller's l greatest extension on one side. In this way, the vibrating roller can compact right up to a high obstacle 5 on one side. It is also possible to supply the vibrating roller 1 with drum units for single arm assembly 2 at both front and rear, as well as e.g. to mirror these so that the vibrating roller I can compact right up to high obstacles on both sides.

Figure 3 shows a known drum unit for single arm assembly 2 on a vibrating roller 1. The known drum unit comprises a drum 4, an eccentric unit 6, a transmission shalt 7, a drum motor 8, a vibration motor 9 and a number of sets of elastic members 10. Each set of elastic members 10 comprises pairs of elastic members, which are arranged after one another in the members' longitudinal direction. The members can be said to interact at one point, situated midway between the members, which from now on will be known as the point of co-operation 11. A tension load in one member will consequently correspond to a thrust load in the other member. The known unit comprises sets of elastic members 10 that are oriented in the same way and arranged around the centre line 12 of the drum 4 and connected to the drum 4 at its points of co-operation 1 1. The sets of elastic members 10 are also arranged so that their points of co-operation 1 1 coincide in an imagined plane, at right angles to the centre line 12 of the drum 4. The imagined plane coincides in the known drum unit with the centre of gravity TP of the vibrating mass, and in this way the elastic members are symmetrically arranged on both sides of this. The mass of the drum 4 constitutes the majority of the vibrating mass in the known unit, and its centre of gravity therefore coincides largely with the centre of gravity TP of the vibrating mass. This arrangement means that it is easier to reach the far members and attach these, as well as the nearest members at one end of the drum motor 8. The drum motor 8, which both rotates the drum and comprises the drum bearing, is attached at its other end to the roller's single arm 3. The drum motor 8 consequently constitutes a spacer between the centre of the drum 4 and the single arm 3. The arrangement means that the extension of the single arm 3 inside the drum 4 can be limited. The vibration motor 9 is rigidly connected to the drum motor 8 and, via a cardan shaft l 3, drives the eccentric unit 6 that then causes the drum 4 to vibrate. In the known arrangement, the choice of drive shaft type is constrained by the necessity for this to allow angular changes in order to follow the movements of the drum 4. The drum motor includes a large clearance D in its centre for the cardan shaft 13.

Figure 4 shows a vertical cross-section of a preferred first version of a drum unit for single arm assembly 2 on a vibrating roller I in accordance with this invention. The drum unit 2 comprises a drum 4, an eccentric unit 6, a transmission shaft 7, a drum motor 8, a vibration motor 9 and a number of sets of elastic members 10. The vibration motor 9 is rigidly connected to the drum motor 8, which in turn is rigidly connected to the drum 4 at one end. The mass of both motors, along with the mass of the drum 4, constitutes the majority of the vibrating mass, which has been distributed in such a way that its centre of gravity TP is in the vicinity of the centre of the drum 4, where the eccentric unit 6 also operates. The eccentric unit 6 comprises one or more eccentric shafts with fixed or adjustable eccentric moment. The drum 4 vibrates when the eccentric shaft is caused to rotate with the vibration motor 9. The drum motor 8 is connected to a single arm 3 at its centre via four sets of elastic members 10. The single arm 3 in turn is rigidly connected to the vibrating roller 1. The transmission shaft 7 comprises a rigid transmission shaft 14. The term "rigid transmission shaft" in this context comprehends all transmission shafts that transfer driving moment during drive rotation around a centre of rotation that coincides with a permanent straight centre line running longitudinally through its centre. The drum motor 8 has an internal clearance D for a rigid transmission shaft 14.

Each set of elastic members 10, as with the known drum unit, comprises pairs of elastic members that are arranged one after another along the centre line 15 of the members and the set of members l 0. The members interact at a point of co l O operation 11, situated midway between the members, which constitutes the set of members' 10 attachment area in the drum motor 8. The points of co-operation 1 1 coincide in an imagined plane 16, at right angles to the drum's 4 centre line 12, and displaced from the centre of gravity TP of the vibrating mass in the direction of the single arm 3. In this way the plane 16 does not coincide with the centre of gravity TP of the vibrating mass. In the preferred version, the sets of elastic members 10 are oriented so that their centre lines 15 converge at a point C situated on the drum's 4 centre line 12. The position of point C on the centre line 12 is one of the factors influencing the location of the shared elastic centre of the sets of members 10. The point C must be positioned so that this shared elastic centre is in the vicinity of or ideally at the centre of gravity TP of the vibrating mass. The theory concerning how a particular geometrical arrangement of sets of members affects their shared elastic centre may for example be obtained from the known theory for elastic arrangement. Extremely good function is also obtained when the sets of members 10 are oriented so that their centre lines 15 are instead at a tangent to an imagined sphere around the point C without converging at a point on the centre line 12. The latter arrangement can be selected when the available space inside the drum 4 does not allow the preferred arrangement. In both cases, the centre lines 15 must have a certain incline in towards the drum's 4 centre line 12. However, it is possible to enlarge the imagined sphere so that the centre lines 12,15 are parallel. Such a version is presented in figure 6.

Figure 5 shows a schematic view, viewed from the right, of the preferred version from figure 4. There are four sets of elastic members and these are arranged so that their centre lines 15 converge at the point C on the centre line 12 of the drum' 4. The points of cooperation 11 coincide in the imagined plane 16. It is also possible to select fewer or more than four sets of members by adapting the dimensions of the members. However, some redundancy will be lost if fewer than four sets of members are selected.

Figure 6 shows a vertical cross-section of a second version of a drum unit for single arm assembly 2 on a vibrating roller 1 in accordance with this invention.

The sets of elastic members 10 are arranged here so that their centre lines 15 are parallel with the centre line 12 of the drum 4. This arrangement ensures good function and can be used when it is not possible to angle the sets of members l O at all. The arrangement is otherwise exactly the same as the preferred version and is intended to be covered by claim 3 of this patent application. . Figure 7 shows a schematic view, viewed from the right, of the second version from figure 6. There are four sets of elastic members and these are arranged so that their centre lines 15 are parallel to the centre line 12 of the drum 4.

In the versions described above, there are four sets of elastic members. As previously mentioned, it is perfectly possible to select fewer or more than four sets of members. It is also possible to allow each set of members to include one or more than two elastic members.

It is financially beneficial to use symmetrically structured elastic members, as these are easy to acquire. However, it is also possible to allow the sets of members to include asymmetrically structured members, which have the properties of angled members, but which eliminate the need for angled connections.

In this application, the centre lines 12 and 15 refer to imagined and infinitely long symmetric lines through and along the geometric centers of the drum 4 and the sets of members l 0, respectively. In order to facilitate the attachment of the individual elastic members in a set of members 10, for example, it is possible to displace these laterally somewhat so that their individual centre lines become parallel or almost parallel. The centre line 15 of the set of members lO must then be defined as a line parallel with and midway between the individual members' centre lines. In cases where the lines are almost parallel, the centre line 15 of the set of members 10 is defined as the bisector of the angle between the individual members' centre lines.

The selections above will be considered to fall within the framework of this invention's concept of invention and are therefore covered by the application's claims. s

Claims

1. A drum unit for single arm assembly on a vibrating roller via a single arm, comprising a drum, an eccentric unit, a transmission shaft for the driving of the eccentric unit, a drum motor with integrated drum bearing and internal clearance for the transmission shaft, a vibration motor rigidly connected to the drum motor and driving the eccentric unit via the transmission shaft, and a number of sets of elastic members, arranged so that their points of co-operation coincide with a plane at right angles to the centre line of the drum, wherein the drum motor is rigidly connected to the drum and elastically connected, via the sets of elastic members to the single arm and wherein said plane does not coincide with the centre of gravity of the vibrating mass.

2. A drum unit in accordance with claim 1, wherein the sets of elastic members are arranged so that their centre lines converge at a point on the centre line of the drum.

3. A drum unit in accordance with claim 1, wherein the sets of elastic members are arranged so that their centre lines are at a tangent to a sphere whose centre is on the centre line of the drum.

4. A drum unit in accordance with claim 1, wherein a number of the sets of elastic members are arranged so that their centre lines converge at a point on the centre line of the drum and wherein others are at a tangent to a sphere whose centre is on the centre line of the drum.

5. A drum unit in accordance with any of claims I to 4, wherein the transmission shaft comprises a rigid transmission shaft.

6. A drum unit in accordance with any of claims 1 to 5, wherein the drum motor has an internal clearance for a rigid transmission shaft.

7. A drum unit substatially as hereinbefore described, with reference to and as illustrated in any of figures 1, 2 and 4 to 7 of the accompanying drawings. s