Conveyor

1. A conveyor, comprising:

two opposite rolls;

a frame that comprises two opposite beams that carry the rolls and extend in their longitudinal direction between the rolls;

an endless metal belt extending in a path around and carried by the two rolls; and

a support element that extends between and is connected to each of the two beams,

wherein at least one of the rolls is displaceable in the longitudinal direction of the beams in order to enable tightening or loosing of the belt,

wherein there is provided a jack that is connected to and acts on said roll for said displacement thereof,

wherein the jack is displaceable between at least two operative positions in the longitudinal direction of the beams,

wherein the jack is connected to and supported by the support element, and

wherein said two positions are on opposite sides of the support element.

2. A conveyor according to claim 1 wherein the support element is arranged so as to permit an adjustment of the distance between the beams by means thereof, and that a dimension of the support element is adjustable in a direction crosswise to the longitudinal direction of the beams so as to enable the adjustment of the distance between the beams.

3. A conveyor according to claim 2 , wherein the dimension of the support element in said direction crosswise to the longitudinal direction of the beams is adjustable in a stepless manner.

4. A conveyor according to claim 2 , wherein the support element comprises at least two parts that are connected to each other through a screw joint, and that the adjustment of the dimension of the support element in said direction crosswise to the longitudinal direction of the beams is a result of one of said parts being screwed in relation to the other part.

5. A conveyor according to claim 2 , wherein the support element comprises at least three parts, two of which are connected to a respective of said beams and a third of which is connected to each of the other parts through a respective screw joint, and wherein the dimension of the support element in said direction crosswise to the longitudinal direction of the beams is adjustable by means of screwing of said third part in relation to said other parts.

6. A conveyor according to claim 1 , wherein at least one of the rolls is displaceable in the longitudinal direction of the beams in order to enable tightening or loosing of the belt, and that the support element is located closer to said displaceable roll than to the opposite other roll.

7. A conveyor according to claim 1 , wherein the rolls have parallel centre lines, and that each beam presents a centre line in its longitudinal direction, and that the centre lines of the rolls and the beams extend in a common plane.

8. A conveyor according to claim 1 , wherein the conveyor comprises a pair of cross-rods that engages the beams.

9. A conveyor according to claim 1 , wherein the conveyor comprises a belt-supporting element arranged so as to support the belt by bearing against the lower surface of an upper strand of the belt.

10. A conveyor according to claim 1 , wherein said support element is tubular, that the frame comprises at least one suspension arm which extends through the beams and on which the beams are suspended, and that the suspension arm extends inside the support element.

11. A conveyor, comprising:

two opposite rolls;

a frame that comprises two opposite beams that carry the rolls and extend in their longitudinal direction between the rolls;

an endless metal belt extending in a path around and carried by the two rolls; and

a support element that extends between and is connected to each of the two beams,

wherein at least one of the rolls is displaceable in the longitudinal direction of the beams in order to enable tightening or loosing of the belt,

wherein there is provided a jack that is connected to and acts on said roll for said displacement thereof,

wherein the jack is displaceable between at least two operative positions in the longitudinal direction of the beams, and

wherein said jack is connected to a belt-lifting element arranged to lift an upper strand of the belt, wherein the jack induces the belt-lifting operation of the lifting element when operated to a predetermined degree in a belt tension-releasing direction.

12. A conveyor, comprising:

two opposite rolls;

a frame that comprises two opposite beams that carry the rolls and extend in their longitudinal direction between the rolls;

an endless metal belt extending in a path around and carried by the two rolls; and

a support element that extends between and is connected to each of the two beams,

wherein at least one of the rolls is displaceable in the longitudinal direction of the beams in order to enable tightening or loosing of the belt,

wherein there is provided a jack that is connected to and acts on said roll for said displacement thereof,

wherein the jack is displaceable between at least two operative positions in the longitudinal direction of the beams, and

wherein the support element is provided with a joint element to which the jack is connected, and that the joint element is displaceable between two positions, one for each of the two positions of the jack.

13. A conveyor according to claim 12 , wherein the support element presents a longitudinal axis crosswise to the longitudinal direction of the beams and that said joint element is rotatable on the support element around the longitudinal axis of the support element between two opposite positions.

14. A conveyor according to claim 12 , wherein the support element is provided with a joint element to which the jack is connected, and that the joint element is displaceable along the support element in a direction cross wise to the longitudinal direction of the beams.

15. A conveyor according to claim 13 wherein the support element is provided with a joint element to which the jack is connected, and that the joint element is displaceable along the support element in a direction cross wise to the longitudinal direction of the beams.