GB2155871A

GB2155871A - Vibrator/roller with disengageable drive arrangement

Info

Publication number: GB2155871A
Application number: GB08407182A
Authority: GB
Inventors: Silva Vivian Raphael De; Terence R Heathcote
Original assignee: Stothert and Pitt Ltd
Current assignee: Stothert and Pitt Ltd
Priority date: 1984-03-20
Filing date: 1984-03-20
Publication date: 1985-10-02
Also published as: GB8407182D0; DE8434376U1; GB2155871B

Abstract

A vibrator/roller is selectively operable in either a vibration mode, or a rolling mode. A belt drive arrangement includes relatively displaceable pulleys 1 and 4 for disengageably coupling an engine drive to one or more vibratory shafts with pulleys 2 and 3. Bowden cable mechanism 13 is hand operated to pivot plate 8 about pivot axis 9 to displace pulley 4 with respect to pulley 1. Tension roller 7 maintains tension in drive belt 6 at all times. <IMAGE>

Description

SPECIFICATION Vibrator/roller with disengageable drive arrangement This invention relates to a vibrator/roller which is selectively operable in either a vibratory mode wherein vibration is imparted to a roller shell, or a rolling mode where no vibration is imparted to the roller shell. A disenageable belt drive arrangement is employed to select one or other of these modes of operation. The vibrator/roller may be used, for example, where soil compaction is required.

Known vibrator/roller devices employ complex and expensive clutch arrangements to select vibratory and rolling modes of operation. Typically, such arrangements include multi-plate disc clutches, centrifugal clutches and auto-motive clutches. All of these are expensive to manufacture and to maintain.

The present invention seeks to provide a vibrator/roller having a relatively simple arrangement for disengageably coupling a drive from means for generating vibrations.

The present invention provides a vibrator/roller selectively operable in either a vibration mode wherein vibration is imparted to a roller shell, or a rolling mode wherein no vibration is imparted to the roller shell, the vibrator/roller further including drive means disengageably coupled to at least one unbalanced member by a belt drive arrangement, the belt drive arrangement including pulleys which are relatively displaceable either to cause the drive means to be driveably coupled to said member in the vibratory mode, or to cause the drive means to be driveably disengaged from said member in the rolling mode.

Advantages of the invention include the elimination of complex clutches, and appreciable saving in manufacture and the need for less maintenance.

Preferably, the belt drive arrangement includes a belt which is, on account of its stiffness and/or shape, caused to move largely or wholly out of contact with one of the pulleys (in the belt drive arrangement) whilst the vibrator/roller is used in the rolling mode. This avoids frictional wear between the pulley and the belt.

The invention facilitates the use of multi-pulley and belt arrangements where, for example, more than one unbalanced member is to be driven to impart vibrations to the roller shell. Where a multibelt arrangement is employed,.a belt tensioning device is preferably used to ensure that the belt system is fully tensioned in the vibratory mode.

An example of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a front view of a belt drive arrangement for a vibrator/roller, and Figure 2 is an elevation, in section, of part of the arrangement shown in Figure 1.

Referring to the drawings, these illustrate the main components of a belt drive arrangement for disengageably coupling an engine drive (pulley 1) to a respective pair of vibrator shafts (pulleys 2,3).

The rotary output of the engine (not shown) drives pulley 1 which, in turn, drives a double pulley 4 by means of a belt 5. As shown in Figure 2, pulley 4 has a smaller diamter portion 4a (engaged by the belt 5) and a larger diameter oortion 4b which engages a belt 6. The belt 6 passes around pulleys 2 and 3 which are fast with respective unbalanced members or vibrator shafts of known construction (not shown), such as eccentrically mounted shafts or shafts having offset weights, which pass axially through respective roller shells (not shown).

The belt 6 also engages a tensioning device comprising a pulley 7 rotatably mounted (in a slot 7a) on a radial member or pivoted plate 8. The plate 8 is supported by pivot 9 and is capable of pivoting so as to move pulley 4 towards and away from pulley 1. An actuator 10 is provided for causing this pivotal movement, the actuator comprising a clevis 11 having one end pivotally connected to the plate 8 and having its other end connected to the inner core 12 of a push-pull cable arrangement including an outer cover 13. A threaded end of the outer cover 13 is secured by nuts to an anchor lug 14. A compression spring 15, mounted about the inner core 12, biases the pivoted plate outwardly so as to tension the belt 6.A hand control of know construction (not shown), such as a handle bar lever (which may also include a further spring to assist the action of spring 15), is operated so as to reciprocate the inner core 12 within the outer cover 13 and hence to pivot plate 8 between its operating positions.

The pulleys 2 and 3 are mounted on shafts which extend through a bulkhead or base plate 16 as shown in Figure 2. Plate 8 is also pivotally supported by bulkhead 16.

A substantially U-shaped member 17 is mounted adjacent, but spaced from the lower semi-circular periphery of pulley 4 so as to retain the belt 5 when slackened (see below).

Figure 1 illustrates one of the operating positions of the plate 8, i.e. where plate 8 has been pivoted so as to move pulley 4 away from pulley 1 hence tensioning belt 5. This pivotal movement would normally slacken the belt 6 except for pulley 7 which acts as a belt tensioner. Spring 15 assists in maintaining the tension in belt 6. In this position, the vibrator/roller is used in a vibration mode wherein the engine is used to drive the vibratory shafts fast with pulleys 2 and 3.

The other operative position (not shown) of pivoted plate 8 is used in a rolling mode where no vibration is imparted by the vibratory shafts to the roller shells. In such a position, the inner core 12 is withdrawn in the outer cover 13 so as to pivot plate 8 anticlockwise hence m cving pulley 4 towards pulley 1 to slacken the belt 5. This movement takes up any slack in belt 6 (i.e. as pulley 7 is moved away from belt 6).

The inherent stiffness and/or shape of belt 5 is such that it tends to return to a circular shape when the plate 8 is pivoted into the "disengaged" position in the rolling mode. The arrangement is such that the slack and (then) substantially circular belt 5 makes contact with the drive pulley 1 at one point only hence reducing frictional wear in the rolling mode.

Whilst the drawings illustrate a preferred embodiment of the invention having two unbalanced members (i.e. a dual vibrator shaft arrangement for transmitting vibrations to respective roller shells), it will be understood that the invention can be generally applied to vibratorirollers having one or more unbalanced members. Where only one unbalanced member is used, only one belt (5) may be necessary, e.g. where pulley 4 drives a vibrator shaft directly.

Claims

1. A vibrator/roller selectively operable in either a vibration mode wherein vibration is imparted to a roller shell, or a rolling mode wherein no vibration is imparted to the roller shell, the vibrator/ roller further including drive means disengageably coupled to at ieast one unbalanced member by belt drive arrangement, the belt drive arrangement including pulleys which are relatively displaceable either to cause the drive means to be driveably coupled to said member in the vibratory mode, or to cause the drive means to be driveably disengaged from said member in the rolling mode.

2. A vibrator/roller according to claim 1 wherein the belt drive arrangement includes a belt which is, of account of its shape and/or stiffness, caused to move largely or wholly out of contact with one of said pulleys in the rolling mode.

3. A vibrator/roller according to claim 2 including means mounted adjacent, but spaced from one of said pulleys in order to retain said belts when slack.

4. A vibrator/roller accordihg to any one of the preceding claims wherein the belt drive arrange ment incudes a first relatively fixed pulley, a second relatively moveable pulley and a first belt entrained about the first and second pulleys; the second pulley being rotatably mounted on a pivoted radial member which can be pivoted either to tension, or to slacken the first belt.

5. A vibrator/roller according to claim 4 wherein the second pulley is a double pulley, the unbalanced member is connected to a third pulley and the second belt is entrained about the second and third pulleys.

6. A vibrator/roller according to claim 5 including a further unbalanced member connected to a fourth pulley about which the second belt is also entrained.

7. A vibrator/roiler according to claim 5 or 6 further including tensioning means supported by said radial member and provided for tensioning the second belt as the first belt is tensioned.

8. A vibrator/roller according to claim 7 wherein said tensioning means includes a fifth pulley rotatably mounted on said radial member and a springbiased actuator for urging the fifth pulley against the second belt.

9. A vibrator/roller substantially as herein described with reference to the accompanying drawings.