Abstract
A device for transporting objects: including at least two rotatably mounted wheels for driving and deflecting a conveyor belt, a closed conveyor belt and several cells for receiving the objects to be transported. The cells are connected to the conveyor belt such that their cell centers define a closed transport path. The conveyor belt is guided around the wheels in such a way that the transport path has an approximately circular section in the region of the wheels and an approximately straight section between the wheels. The device further includes an element for changing the curvature of the transport path in between at least one straight path section and at least one circular path section.
Claims
1.-15. (canceled)
16. A device for transporting objects comprising: at least two rotatably mounted wheels for driving and deflecting a conveyor belt, a closed conveyor belt, and an element for changing curvature of the conveyor belt in a region between at least one straight path section and at least one circular path section, wherein the element for changing the curvature of the conveyor belt is a wedge, wherein the conveyor belt is guided around the wheels in such a way that a transport path respectively comprises an approximately circular path section in the region of the wheels and respectively comprises an approximately straight path section in the region between the wheels, further comprising several cells for receiving the objects to be transported, and wherein the cells are connected to the conveyor belt and centers of each of the several cells define a closed transport path of the objects to be transported, and the wedge element has an inner side that is assigned to the wheel and an outer side that is assigned to the conveyor belt.
17. The device according to claim 16, further comprising an element for changing the curvature of the transport path in between each straight path section and each circular path section.
18. The device according to claim 16, further comprising an element for changing the curvature of the conveyor belt in between each straight path section and each circular path section.
19. The device according to claim 16, wherein the outer side of the wedge element has a curvature that monotonically increases in a direction of the transport path or a curvature that monotonically decreases in the direction of the transport path.
20. The device according to claim 16, wherein the outer side of the wedge element has on one side a curvature corresponding to the transport path in a region of one of the circular path sections and on another side no curvature at all.
21. The device according to claim 16, wherein the outer side of the wedge element has a length in the range between 100 mm and 700 mm in the direction of the transport path.
22. The device according to claim 16, wherein the outer side of the wedge element comprises a curve, the curve being proportional to its length.
23. The device according to claim 16, wherein the outer side of the wedge element comprises a polynomial.
24. The device according to claim 16, wherein the wedge element has at least one finger.
25. The device according to claim 16, wherein the conveyor belt is in a region of at least one straight path section outwardly offset relative to a tangential connection between two adjacent wheels by a distance between 5 mm and 100 mm.
26. The device according to claim 21, wherein the length of the outer side of the wedge element is between 100 mm and 500 mm.
Description
[0033] The invention is described in greater detail below with reference to the drawings that merely show a preferred exemplary embodiment. In these drawings,
[0034] FIG. 1A shows a top view of a device for transporting objects according to the prior art,
[0035] FIG. 1B shows the progression of the curvature along the transport path in the device according to FIG. 1A,
[0036] FIG. 2A shows a top view of a first embodiment of an inventive device for transporting objects,
[0037] FIG. 2B shows the extent of the curvature along the transport path in the device according to FIG. 2A,
[0038] FIG. 2C shows an enlarged view of the transition between a circular path section and a straight path section in the device according to FIG. 2A without the conveyor belt,
[0039] FIG. 2D shows an enlarged view of the transition between a circular path section and a straight path section in the device according to FIG. 2A with the conveyor belt,
[0040] FIG. 3A shows a top view of a second embodiment of an inventive device for transporting objects, and
[0041] FIG. 3B shows the progression of the curvature along the transport path in the device according to FIG. 3A.
[0042] FIG. 1A shows a top view of a device 1 for transporting objects according to the prior art. The device 1 comprises two wheels 2, 3, around which a conveyor belt 4 is guided. Cells 5 capable of receiving the objects to be transported are equidistantly arranged on the conveyor belt 4. The objects transported in the cells 5 therefore move along a path that extends through the centers of the cells 5 and is referred to as transport path 6. The larger wheel 3 has a radius R3 and drives the conveyor belt 4; the smaller wheel 2 has a radius R2, wherein this smaller wheel merely deflects and is turned by the conveyor belt 4. For example, the two wheels 2, 3 rotate in the clockwise direction (indicated with arrows in FIG. 1A).
[0043] In the device 1 illustrated in FIG. 1A, the transport path 6 to be traveled by the transported objects is composed of four sections: the path section a extends straight from the small wheel 2 to the large wheel 3. The path section b, in contrast, extends circularly around the wheel 3 over an angle .sub.b with a radius RT3 that is slightly larger than the radius R3. The path section c once again extends straight from the large wheel 3 back to the small wheel 2. The path section d ultimately extends circularly around the wheel 2 over an angle .sub.d with a radius RT2 that is slightly larger than the radius R2. The end of the path section d is once again followed by the beginning of the path section a such that the path sections a, b, c, d jointly form a revolving and closed transport path 6. The two straight path sections a, c lie on tangents on the circles formed by the wheels 2, 3. In the device 1 illustrated in FIG. 1A, the two straight path sections a, c and the two circular path sections b, d therefore tangentially transform into one another. Since the left wheel 2 is smaller than the right wheel 3, the angle .sub.d is also smaller than the angle .sub.b; however, the sum of the two angles amounts to 360as it is always the case with two wheel wrap angles.
[0044] FIG. 1B shows the progression of the curvature along the transport path 6 in the device 1 according to FIG. 1A. In this diagram, the transport path 6 is illustrated on the horizontal axis whereas the curvature of the transport path 6 is illustrated on the vertical axis. The curvature corresponds to the reciprocal value of the radius. According to this diagram, the curvature of the first path section a amounts to zero because the path section a is a straight path section. At the transition from the path section a to the path section b, the curvature of the transport path 6 abruptly increases to a value 1/RT3 that corresponds to the curvature of the transport path 6 in the region of the circular path section b. At the transition from the path section b to the path section c, the curvature of the transport path 6 once again decreases just as abruptly to a value zero that corresponds to the curvature in the region of the straight path section c. At the transition from the path section c to the path section d, the curvature of the transport path 6 once again abruptly increases to a value 1/RT2 that corresponds to the curvature of the transport path 6 in the region of the circular path section d. Subsequently, the curvature of the transport path 6 once again decreases just as abruptly to a value zero that corresponds to the curvature in the region of the straight path section a.
[0045] The progression of the curvature illustrated in FIG. 1B reveals that four abrupt changes of the curvature of the transport path 6 occur during one complete revolution of the conveyor belt 4, namely at each transition between a straight path section a, c and a circular path section b, d. Since a change of the curvature of the transport path 6 always results in an acceleration of the transported objectsas already described initiallysignificant accelerations, as well as jerky loads, occur in the device 1 illustrated in FIG. 1A at the transitions between the straight path sections a, c and the circular path sections b, d due to the abrupt changes of the curvature of the transport path 6.
[0046] FIG. 2A shows a top view of a first embodiment of an inventive device 1 for transporting objects. The device 1 illustrated in FIG. 2A and the above-described device 1 according to FIG. 1A have a few similarities such that the parts of the device illustrated in FIG. 2A, which were already described above in connection with FIG. 1A and FIG. 1B, are identified by corresponding reference symbols. The device 1 also comprises two wheels 2, 3, around which adifferently runningconveyor belt 4 is guided. Cells 5 capable of receiving the objects to be transported are once again equidistantly arranged on the conveyor belt 4. A transport path 6 extends through the centers of the cells 5. The larger wheel 3 has a radius R3 and drives the conveyor belt 4; the smaller wheel 2 has a radius R2, wherein this smaller wheel merely deflects and is turned by the conveyor belt 4. For example, the two wheels 2, 3 also rotate in the clockwise direction (indicated with arrows in FIG. 2A) in this case.
[0047] One distinction between the device 1 illustrated in FIG. 2A and the above-described device 1 (FIG. 1A) can be seen in an optimized transport path 6: the transport path 6 to be traveled by the transported objects is now composed of eight sections: the path section A extends straight from the small wheel 2 to the large wheel 3. The next path section AB, in contrast, extends spirally over an angle .sub.AB and at the beginning has a radius RT3.sub.max that continuously decreases to a radius RT3.sub.min. The path section AB transforms into a path section B that circularly extends around the wheel 3 over an angle .sub.B with the radius RT3.sub.min. This path section is followed by a path section BC that extends spirally over an angle .sub.BC and at the beginning has the radius RT3.sub.min that continuously increases to the radius RT3.sub.max. The following path section C once again extends straight from the large wheel 3 back to the small wheel 2. The next path section CD once again extends spirally over an angle .sub.CD and at the beginning has a radius RT2.sub.max that continuously decreases to a radius RT2.sub.min. The path section CD transforms into a path section D that circularly extends around the wheel 2 over an angle .sub.D with the radius R2. This path section is followed by another path section DA that spirally extends over an angle .sub.DA and at the beginning has the radius RT2.sub.min that continuously increases to the radius RT2.sub.max. The end of the path section DA is once again followed by the beginning of the path section A such that the path sections A, AB, B, BC, C, CD, D, DA jointly form a complete revolving and closed transport path 6. For example, the spirally extending path sections AB, BC, CD and DA may have the shape of a clothoid.
[0048] In the device 1 illustrated in FIG. 2A, the conveyor belt 4 runsin contrast to the device 1 according to FIG. 1Ano longer on tangents on the circles formed by the wheels 2, 3 in the region of the two straight path sections A and C. Instead, the conveyor belt 4 is arranged outside these tangents and has an offset 7 relative thereto (the extent of the tangents is illustrated with broken lines in FIG. 2A) in the region of the two straight path sections A and C. This route of the conveyor belt 4 is achieved, for example, with wedge elements 8 that are described in greater detail below in connection with FIG. 2C and FIG. 2D. The offset 7 may lie in the range between 5 mm and 100 mm. In addition, an offset 7 is created between the transport path 6 and the tangents, wherein this offset may lie in the range between 10 mm and 130 mm and therefore isdepending on the cell mountingslightly larger than the offset 7 between the conveyor belt 4 and the tangents. The offset 7 and the offset 7 may be constant (R2.sub.max=R3.sub.max) or variable (R2.sub.maxR3.sub.max) in the straight path sections A, C. The angles .sub.AB, .sub.BC, .sub.CD and .sub.DA of the spirally extending path sections AB, BC, CD and DA may lie in the range between 10 and 30.
[0049] FIG. 2B shows the progression of the curvature along the transport path 6 in the device 1 according to FIG. 2A. In this diagram, the transport path 6 isanalogous to FIG. 1Billustrated on the horizontal axis whereas the curvature of the transport path 6 is illustrated on the vertical axis. The curvature corresponds to the reciprocal value of the radius. According to this diagram, the curvature of the first path section A amounts to zero because the path section A is a straight path section. At the transition from the path section A to the path section B, the curvature of the transport path slowly increases in the region of the path section AB to a value 1/RT3.sub.min that corresponds to the curvature of the transport path 6 in the region of the circular path section B. The curvature may increase in a linear (continuous line) or polynomial (broken line) fashion. At the transition from the path section B to the path section C, the curvature of the transport path 6 once again decreases just as slowly in the region of the path section BC to a value zero that corresponds to the curvature in the region of the straight path section C. The curvature may also decrease in a linear (continuous line) or polynomial (broken line) fashion. At the transition from the path section C to the path section D, the curvature of the transport path 6 once again slowly increases in the region of the path section CD to a value 1/RT2.sub.min that corresponds to the curvature of the transport path 6 in the region of the circular path section D. This increase may also take place in a linear (continuous line) or polynomial (broken line) fashion. Subsequently, the curvature of the transport path slowly decreases in the region of the path section DA to a value zero that corresponds to the curvature in the region of the straight path section A. This decrease of the curvature may likewise take place in a linear (continuous line) or polynomial (broken line) fashion.
[0050] The progression of the curvature illustrated in FIG. 2B reveals that abrupt changes of the curvature of the transport path 6 no longer occur in the device 1. Due to the design of the path sections AB, BC, CD and DA, the curvature is instead uniformly and slowly adapted to the curvature of the following path section in the critical regions, namely at each transition between a straight path section A, C and a circular path section B, D. Since a change of the curvature of the transport path 6 always results in an acceleration of the transported objectsas already described initiallythe accelerations occurring in the device 1 illustrated in FIG. 2A at the transitions between the straight path sections A, C and the circular path sections B, D are significantly reduced in comparison with the device 1 illustrated in FIG. 1A.
[0051] FIG. 2C shows an enlarged view of the transition between a circular path section and a straight path section in the device 1 according to FIG. 2A without the conveyor belt. The transition shown consists of the transition between the circular path section D and the straight path section C formed by the path section CD. This figure shows the wheel 2 that features several continuous grooves 9 on its circumference. In addition, one of the aforementioned wedge elements 8 is provided in the path section CD, wherein said wedge element features several protruding fingers 10 that engage into the grooves 9 of the wheel 2. In this way, the conveyor belt 4 can be guided without jerks in the described transition. Since the outer surface of the wedge element 8 represents part of the guideway of the conveyor belt 4, the wedge element 8 is during the operation subjected to considerable tension that is absorbed by the fingers 10, in particular, in the outlet region of the wedge element 8 (at the location, at which the wedge element 8 is tapered like a blade). The wedge element 8 also has an inner side 11 assigned to the wheel 2 and an outer side 12 assigned to the conveyor belt 4 (that is not illustrated in FIG. 2C). The inner side 11 of the wedge element 8 preferably has a circular shape and a radius that approximately corresponds to the radius R2 of the wheel 2 assigned thereto. The outer side 12 of the wedge element 8, in contrast, has an increasing curvature referred to the transport direction. It is preferred that the curvature of the outer side 12 approximately corresponds to zero on the side assigned to the straight path section C and approximately reaches the curvature of the transport path 6 in the region of the circular path section D (1/RT2.sub.min) on the side assigned to the circular path section D.
[0052] FIG. 2D shows an enlarged view of the transition between a circular path section and a straight path section in the device 1 according to FIG. 2A with the conveyor belt 4. The illustration in FIG. 2D can be distinguished from the illustration in FIG. 2C, in particular, in that the revolving conveyor belt 4 is installed. However, the cells 5 are not illustrated in order to provide a better overview. According to this figure, the conveyor belt 4 is guided over the stationary wedge element 8 and slides thereon in the region of the path section CD. In this way, the conveyor belt 4 assumes the shape of the outer side 12 of the wedge element 8 in the region of the path section CD. Consequently, the extent of the conveyor belt 4and therefore also of the transport path 6can be sectionally defined by the shape of the wedge element 8, particularly the shape of its outer side 12.
[0053] FIG. 3A shows a top view of a second embodiment of an inventive device 1 for transporting objects. The areas of the device, which were already described in connection with FIG. 1A to FIG. 2D, are identified by corresponding reference symbols in FIG. 3A. One significant distinction between the device 1 illustrated in FIG. 3A and the above-described device 1 can be seen in that the cells 5 are connected to the conveyor belt 4 by means of arms 13 that can be adjusted during the operation of the device 1. Consequently, the distance between the conveyor belt 4 and the cells 5 can be varied such that the transport path 6 of the objects transported by the cells 5 doesin contrast to the above-described device 1not necessarily have to extend parallel to the conveyor belt 4. In this way, an optimized transport path 6 (as illustrated in FIG. 2A) can also be achieved with a conveyor belt 4 that has tangential sections (as illustrated in FIG. 1A). The transport path 6 is also illustrated with broken lines in FIG. 3A; it once again corresponds to the path of the centers of the cells 5 and is identical to the transport path 6 illustrated in FIG. 2Adespite the different extent of the conveyor belt 4. An offset 7, which may lie in the range between 5 mm and 100 mm, is therefore created between the straight path sections A, C of the transport path 6 and the tangentially extending conveyor belt 4. Due to the adjustability of the arms 13, the wedge elements 8 can be eliminated in the device 1 illustrated in FIG. 3A. However, a combination of wedge element 8 and adjustable arms 13 could conceivably also be used.
[0054] FIG. 3B ultimately shows the progression of the curvature along the transport path 6 in the device 1 according to FIG. 3A. Due to the identical transport paths 6 and 6, FIG. 3B exactly corresponds to FIG. 2B and we therefore refer to the description thereof in this respect.
[0055] LIST OF REFERENCE SYMBOLS
[0056] 1, 1, 1: Device for transporting objects
[0057] 2, 3: Wheel
[0058] 4, 4, 4: Conveyor belt
[0059] 5, 5, 5: Cell
[0060] 6, 6, 6: Transport path
[0061] 7, 7, 7: Offset
[0062] 8: Wedge element
[0063] 9: Groove
[0064] 10: Finger
[0065] 11: Inner side of wedge element
[0066] 12: Outer side of wedge element
[0067] 13: Adjustable arm
[0068] A, a, C, c: Straight path section
[0069] B, b, D, d: Circular path section
[0070] AB, BC, CD, DA: Spirally extending path section
[0071] R2: Radius of wheel 2
[0072] RT2: Radius of transport path in the region of the wheel 2
[0073] RT2.sub.min: Smallest radius of transport path in the region of the wheel 2
[0074] RT2.sub.max: Greatest radius of transport path in the region of the wheel 2
[0075] R3: Radius of wheel 3
[0076] RT3: Radius of transport path in the region of the wheel 3
[0077] RT3.sub.min: Smallest radius of transport path in the region of the wheel 3
[0078] RT3.sub.max: Greatest radius of transport path in the region of the wheel 3
[0079] .sub.b: Angular range of path section b
[0080] .sub.d: Angular range of path section d
[0081] .sub.AB: Angular range of path section AB
[0082] .sub.B: Angular range of path section B
[0083] .sub.BC: Angular range of path section BC
[0084] .sub.CD: Angular range of path section CD
[0085] .sub.D: Angular range of path section D
[0086] .sub.DA: Angular range of path section DA
