Contact Guard for a Belt Drive

Abstract

A contact guard for a belt drive, in which a filling space formed between two pulleys and the belt is filled by a filling body, which includes two sub-bodies that can be moved relative to one another.

Claims

1. A belt drive, in which a belt driven by a first pulley disposed on a first axle drives a second pulley, which is disposed on a second axle spaced apart from the first axle in a first direction (Z) and parallel to it, wherein the first axle and the second axle extend in a second direction (Y) perpendicular to the first direction (Z), and a third direction (X) extends perpendicular to the first and second direction (Z, Y), a) wherein a filling body is disposed as a contact guard in a filling space circumscribed by the first pulley and second pulley and an inner side of the tightened belt, and b) wherein a width, in the X direction, of a belt run gap that remains between a guard section of the filling body and an inner side of the belt is smaller than a predeterminable dimension and c) wherein the filling body has a first sub-body that is fixed in place relative to the first pulley, and a second sub-body that is fixed in place relative to the second pulley, and wherein the first sub-body and second sub-body can be displaced relative to one another, wherein d) the first sub-body and the second sub-body form an overlap in the Y direction.

2. The belt drive according to claim 1, wherein the first sub-body and second sub-body form the overlap in that at least one projection of the second sub-body dips into at least one depression of the first sub-body.

3. The belt drive according to claim 1, wherein a width of the belt in the Y direction is smaller than or equal to a) a width of the guard section in the Y direction, or b) a clear distance that exists in the Y direction between two cover sections that surround the belt laterally.

4. The belt drive according to claim 1, wherein the overlap is maintained during a predeterminable change in distance between the first axle and second axle, in that an immersion depth of a projection into a depression and thereby the height, in the Z direction, of a resulting lift gap changes.

5. The belt drive according to claim 1, wherein the guard section is formed at least in part by a projection.

6. The belt drive according to claim 1, wherein at least one section of the filling body surrounds the belt laterally.

7. The belt drive according to claim 1, wherein an inner side of each belt run section of the belt that is under tension is always protected against contact even during and after a change in the distance between the first axle and the second axle, within a predeterminable extent, by at least one of the first sub-body and second sub-body, in that a) a section of a sub-body laterally covers the belt run section and an adjacent part of the filling space, and/or b) a guard section of a sub-body forms the belt run gap on the inside of the belt run section.

8. The belt drive according to claim 1, wherein a sub-body has at least one core section disposed in the filling space, which is followed in the Y direction, on both sides, in each instance, by a cover section wherein the cover section delimits the filling space in the Y direction and covers the belt edge, at least in part.

9. A filling body for a belt drive according to claim 1.

10. A transport system comprising a belt drive according to claim 1, wherein the distance between the first axle and the second axle can be reduced for removal of the belt, and can be increased to tighten a belt.

11. The transport system according to claim 10, comprising a) a motor chassis having a motor, the first pulley, and the first sub-body, and b) a belt chassis having a conveyor belt, the second pulley, and the second sub-body, c) wherein the distance between the first axle and the second axle can be changed by means of pivoting the belt chassis relative to the motor chassis.

12. The transport system according to claim 10, wherein the transport system forms a pre-load for a weighing sensor.

13. A method for replacing a belt on a belt drive according to claim 1, comprising the following method steps: a) reducing the distance between the first axle and second axle in order to reduce a tension of the belt to such an extent that the belt can be removed, without tools, from at least one pulley, wherein the first sub-body and the second sub-body move toward one another, b) replacing the belt, c) increasing the distance between the first axle and the second axle in order to tighten the belt so as to be ready for operation, wherein d) the first sub-body and the second sub-body continuously fill the filling space during steps a) to c) in such a manner that the overlap is maintained.

14. The belt drive according to claim 8, wherein the cover section is connected in one piece with the core section.

15. The belt drive according to claim 1, wherein the predeterminable dimension is a width of a human finger.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] An advantageous embodiment of a contact guard according to the invention will be explained in greater detail below, using an example from the figures. In this regard,

[0031] FIG. 1 shows a transport system having a belt drive, in the working position,

[0032] FIG. 2 shows the belt drive of the transport system in an enlarged representation,

[0033] FIG. 3a shows the filling space formed between the pulleys and the belt in a side view,

[0034] FIG. 3b shows the belt drive in a side view, with sub-bodies inserted,

[0035] FIG. 4a, 4b show the sub-bodies in different positions relative to one another,

[0036] FIG. 5a, 5b show the sub-bodies in a separate representation, and

[0037] FIG. 6a, 6b show a transport system in the release position, with an enlarged representation of the belt drive.

DETAILED DESCRIPTION OF THE INVENTION

[0038] FIG. 1, in a perspective view, shows a transport system for use in inspection technology (for example weighing technology, X-ray technology, track-and-trace system). The transport system C comprises a motor chassis H.sub.M and a belt chassis H.sub.B disposed so as to pivot relative to the former. The motor chassis H.sub.M carries a motor M, which drives a first pulley S.sub.1 by way of a transmission T indicated in FIG. 2.

[0039] The pulley S.sub.1 sits on a first axle A.sub.1 that runs in the Y direction. The first pulley S.sub.1 drives a second pulley S.sub.2 by way of a belt L, which pulley sits on a second axle A.sub.2 disposed above the first axle A.sub.1 in a Z direction, which axle runs parallel to the first axle A.sub.1. The second pulley S.sub.2 is part of the belt chassis H.sub.B and is coupled with a roller, which in turn drives a conveyor belt B. After release of a quick-release connection, the belt chassis H.sub.B can be pivoted relative to the motor chassis H.sub.M by way of a pivot mechanism, not shown in any detail, in such a manner that the Z distance between the axles A.sub.1 and A.sub.2 changes during this process. In the working distance shown in FIG. 1, the axle distance is selected in such a manner that the belt L looped around the pulleys S.sub.1, S.sub.2 is under tension and ready for operation.

[0040] FIG. 2 shows the belt drive of the transport system from FIG. 1 in an enlarged representation. The first pulley S.sub.1 of the motor chassis H.sub.M, together with the second pulley S.sub.2 of the belt chassis H.sub.B and with the belt L that circulates around the two pulleys, delimits a space that is shown in simplified manner in FIG. 3a, as a filling space R. During operation of the belt drive, objects or human limbs are supposed to be prevented from getting into the filling space R, in order to prevent damage to the drive or injury of an operator.

[0041] As can be seen in FIG. 2 and in greater detail in FIGS. 3b and 4a, for this purpose two sub-bodies K.sub.1 and K.sub.2 are positioned in the filling space R, which sub-bodies fill this space to such an extent that unintentional penetration, particularly of human limbs, is reliably prevented. For this purpose, a first sub-body K.sub.1 is attached to the motor chassis H.sub.M in the lower part of the filling space R and fixed in place relative to the first pulley S.sub.1. A second sub-body K.sub.2 is disposed in the upper half of the filling space R and fixed in place on the belt chassis H.sub.B relative to the second pulley S.sub.2.

[0042] FIG. 3b shows a simplified sectional representation of the placement of the filling bodies K.sub.1, K.sub.2, with cross-hatching being left out for the sake of clarity. The section plane Q (see FIG. 4) lies at half the belt width and runs through the center of the filling space R. The lower first sub-body K.sub.1 lies closely against the circumference or contour of the first pulley S.sub.1 and extends slightly in the direction toward the second pulley S.sub.2. In this regard, the first sub-body K.sub.1 forms a narrow belt run gap G between itself and the inner side of each run of the belt L, which gap is clearly narrower than the thickness of a human finger or of a definable contact gap. The upper second sub-body K.sub.2 has a similar structure and lies closely against the contour of the second pulley S.sub.2 with its upper end. Furthermore, it extends in the direction toward the first pulley S.sub.1 and also forms the narrow belt run gap G between itself and the inner side of the two runs of the belt L.

[0043] A lift gap M remains between the two sub-bodies K.sub.1, K.sub.2, which gap changes as the axle distance A.sub.1-A.sub.2 changes. In the region of the lift gap M, no body lies opposite the inner side of the belt L. In order to prevent unintentional contact in this region, as well, the first sub-body comprises cover sections (D.sub.1a, D.sub.1b), as can be seen in FIG. 4a, for example.

[0044] FIG. 4a shows the two sub-bodies K.sub.1, K.sub.2 in a perspective and non-sectional representation (the section plane Q selected in FIG. 3b is indicated with a broken line). A lower section of the second sub-body K.sub.2, configured as a projection V, projects into a depression N with a changeable immersion depth; this depression is formed by a first core section F.sub.1 and two cover sections D.sub.1a, D.sub.1b of the first sub-body K.sub.1 that lie opposite one another in the Y direction. The projection V is simultaneously part of a core section F.sub.2 that belongs to the second sub-body K.sub.2. The core section F.sub.2 is also laterally surrounded by two cover sections D.sub.2a, D.sub.2b that lie opposite one another in the Y direction. The Y distance of the cover sections D.sub.1a or D.sub.1b relative to D.sub.2a or D.sub.2b, is selected to be slightly wider, in each instance, than the Y width of the belt L, a short section of which can be seen in FIG. 5b.

[0045] The placement of the sub-bodies K.sub.1 and K.sub.2 relative to one another, which can be seen in FIG. 4a, corresponds to the placement shown in FIG. 1 and FIG. 2, in which the belt chassis has assumed the working position and the belt L has the required tension. To release or replace the belt L, the belt chassis—as shown in FIGS. 6a and 6b—is pivoted slightly upward relative to the motor chassis H.sub.M, after a quick-release connection that prevents pivoting and can be manually activated was released. In this way, the distance between the axles A.sub.1, A.sub.2 is reduced. The belt L thereby loses its tension and can be removed from the pulleys S.sub.1, S.sub.2 and replaced with another belt.

[0046] During the reduction of the axle distance, during which the sub-bodies K.sub.1, K.sub.2, which are fixed in place, in each instance, move toward one another, the projection V of the second core section F.sub.2 of the second sub-body K.sub.2 dips deeper into the depression N of the first sub-body K.sub.1, with the gap height of the lift gap M in the Z direction being reduced. This case is shown in FIG. 4b, where the projection V is completely immersed between the two cover sections D.sub.1a, D.sub.1b of the first sub-body. Because of the pivoting movement of the belt chassis H.sub.B relative to the motor chassis H.sub.M, the immersion movement of the projection V into the first sub-body K.sub.1 does not take place in purely translational manner, but rather at a pivot angle α. A conical joint E that exists between the lower cover sections D.sub.1a, D.sub.1b and the upper cover sections D.sub.2a, D.sub.2b before immersion is accordingly reduced to a small dimension during immersion.

[0047] The belt L, not shown in FIGS. 4a and 4b, is guided between the cover sections D.sub.1a, D.sub.1b, D.sub.2a, D.sub.2b and lies closely against the core sections F.sub.1 and F.sub.2, as indicated in FIG. 2, during operation. The contact guard according to the invention is ensured by means of a combination of two guard mechanisms, in this regard: The core sections F.sub.1 and F.sub.2 of the first and second sub-body K.sub.1 and K.sub.2 are configured in such a manner that when the belt is under tension, they extend along the inner side of the runs of the belt L with a guard section P.sub.1, P.sub.2 and thereby form the narrow belt run gap G. With the exception of the lift gap M, in which the belt cannot be supported in this manner on the inner side, the contact guard is ensured by means of this narrow belt run gap G. The run section that passes over the lift gap M is instead surrounded laterally, at its edge, by the cover sections D.sub.1a and D.sub.1b, so that in this region, too, contact with the belt is effectively prevented.

[0048] The cover sections D.sub.1a and D.sub.1b of the first sub-body K.sub.1 are configured in such a manner that they surround the belt L laterally even on the other side of the lift gap M, thereby additionally stabilizing the operation of the belt and further improving the contact guard. Accordingly, cover sections D.sub.2a and D.sub.2b for laterally surrounding the belt (not shown in FIG. 4a) are also formed on the second sub-body K.sub.2.

[0049] FIGS. 5a and 5b show the sub-bodies K.sub.1 and K.sub.2 in a separate representation. In this regard, it can be seen how the core section F.sub.2 of the second sub-body K.sub.2 forms not only the projection V for immersion into the depression N of the first sub-body, but also the opposite guard sections P, which guide the belt L with the narrow belt run gap G. In FIG. 5b, a short section of the belt L is shown lying tightly against a guard section P of the second sub-body K.sub.2, with the belt run gap G being formed between guard section P and the inner side of the belt L. Laterally, the belt L is surrounded by the cover sections D.sub.2a and D.sub.2b of the second sub-body K.sub.2, which project laterally slightly beyond the core section F.sub.2 for this purpose.

REFERENCE SYMBOL LIST

[0050] A.sub.1, A.sub.2 first axle, second axle [0051] S.sub.1, S.sub.2 first pulley, second pulley [0052] L belt [0053] R filling space [0054] K filling body [0055] E joint [0056] G belt run gap [0057] M lift gap [0058] Q section line [0059] K.sub.1, K.sub.2 first sub-body, second sub-body [0060] P guard section [0061] V projection [0062] N depression [0063] D.sub.1a, D.sub.1b, D.sub.2a, D.sub.2b cover section [0064] F.sub.1, F.sub.2 core section [0065] C transport system [0066] B conveyor belt [0067] H.sub.M motor chassis [0068] H.sub.B belt chassis [0069] T gear mechanism