Hedin, Johan (Valfrid Brodds väg 5, Hässelby, S-165 71, SE)
Yance Paredes, Svetlana (Lommarvägen 31, Norrtälje, S-761 52, SE)
Kruse, Karin (Norr Mälarstrand 52, 3tr, Stockholm, S-112 20, SE)
Studic, Stefan (Malmvägen 8A, Sollentuna, S-191 61, SE)
Jonsson, Mikael (Ibsengatan 65, Bromma, S-168 47, SE)
Hedin, Johan (Valfrid Brodds väg 5, Hässelby, S-165 71, SE)
Yance Paredes, Svetlana (Lommarvägen 31, Norrtälje, S-761 52, SE)
Kruse, Karin (Norr Mälarstrand 52, 3tr, Stockholm, S-112 20, SE)
Studic, Stefan (Malmvägen 8A, Sollentuna, S-191 61, SE)
| 1. | An apparatus for positioning an object (43) in angularly separated rotary positions (3033) around an axis of rotation (40), characterized by two force actuators (1; 101) of which each has a first end that is pivotally supported around a stationary pivot axis (10) being parallel to the axis (40) of rotation and each has an end (16) that is displaceable towards and away from the first end, in that the pivot axes (10) of the force actuators are spaced an equal distance from the axis of rotation (40), whereby this distance lies between the maximum and minimum distance between the ends of the force actuators, in that the second ends (16) of the two force actuators (1 ; 101) are connected to a follower body (14), in that the object (43) has a slot (44) that is directed in a radial direction towards the axis of rotation (40) and that substantially without radial play receives the follower body (14) and in that the force actuators (1; 101) have a common control device (60,61) allowing for an adjustment of the force actuators with a mutual time interval to transfer the object to the successive rotary positions (3033). |
| 2. | An apparatus according to claim 1, characterized in that the force actuators (1; 101) are adjustable between two distinct end positions for positioning the object (43) between four angularly separated rotary positions (3033). |
| 3. | An apparatus according to claims 1 or 2, characterized in that the force actuators (1) are pneumatic cylinders. |
| 4. | An apparatus according to any of claims 13, characterized in that the force actuators (1; 101) have mutually equal stroke length and equal maximum length between their pivot axis and the follower body, so that adjacent rotary positions are separated by 90°. |
| 5. | An apparatus according to claim 1, characterized in that the force actuators (101) are adjustable between selectable positions for positioning the object (43) between an optional number of selectively separated rotary positions (130134). |
| 6. | An apparatus according to any of claims 15, characterized in that the force actuators (1; 101) are linear force actuators. |
| 7. | An apparatus according to any of claims 16, characterized in that the force actuators (1; 101) are hydraulic cylinders, electromagnets or mechanical drive means such as rack and pinion gears. |
| 8. | An apparatus according to any of claims 17, characterized in that the object (43) supports a workpiece carrier (50). |
| 9. | An apparatus according to any of claims 18, characterized in that the angle between the directions of operation of the force actuators (1; 101) does not pass 180°. |
BACKGROUND It is many times desirable to be able to rotate an object to distinct positions in one plane around an axis that is perpendicular thereto, to be able to firmly maintain the object in the respective rotary position and to be able to quickly shift the object between said rotary positions. Conventionally, complicated and expensive rotary actuators such as electrical or hydraulic motors are frequently employed for performing such tasks.
SUMMARY A general object of the invention is to provide an improved apparatus for rotating an object to distinct rotary positions around an axis.
A specific object of the invention is to provide an uncomplicated, reliable and inexpensive apparatus for positioning an object in different rotary positions around an axis of rotation.
Briefly, the invention suggests an apparatus for adjusting an object between distinct angular positions by means of two force actuators capable of assuming distinct positions. The actu- ators each have one end that is pivotal around a separate stationary pivot axis and another displaceable end that is connected to a common follower body slidingly engaging a slot in the object. This apparatus is comparatively uncomplicated and inexpensive and yet permits rapid adjustment between the different positions without any tendency towards locking. Specifically, one advantage of the invention is that it only requires two force actuators.
In an embodiment of the invention the positioning apparatus comprises force actuators having two distinct end positions allowing adjustment of the object between four distinct angularly
spaced positions. In one specific embodiment the four distinct angular positions are spaced 90° from each other.
In a further embodiment of the invention the positioning apparatus comprises force actuators having selectable operating positions allowing adjustment of the object between a number of selectable positions.
In further practical embodiments of the invention the force actuators are linear actuators, such as pneumatic or hydraulic cylinders.
These and further objects of the invention are met by the invention as defined in the appended patent claims.
Advantages offered by the present invention, in addition to those described above, will be readily appreciated upon reading the below detailed description of embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS The invention, together with further objects and advantages thereof, may best be understood by referring to the following description taken together with the accompanying drawings, in which: Fig. 1 is a schematic side view of one embodiment of an apparatus according to the invention; Fig. 2 is a schematic view in section, taken along the line II-II in fig. 1; and Fig. 3 is a view corresponding to that of fig. 1 of an alternative embodiment of the apparatus according to the invention.
DETAILED DESCRIPTION OF EMBODIMENTS In fig. 1 is illustrated a simple embodiment of the apparatus according to the invention. Fig. 1 illustrates a shaft 42 that by means of a bearing 46 is journalled for rotation around an axis 40 that in the illustration is vertical. The shaft 42 carries a rotary plate or disc 43 having a slot 44 that is directed in a radial direction towards the axis 40 and that is illustrated to be outwardly open. A round follower body 14 is received in the slot 44, and is received essentially without
play between the walls of the slot 44. The follower body 14 is supported at the end of a shaft 13 that is directed parallel to the axis 40. The shaft is received essentially without play in coaxial bores in the legs of a pair of forks 16 that are connected to the piston rod ends of a pair of mutu- ally equal pneumatic cylinders 1. Thus, the piston rod ends are pivotally connected to each other, whereas the cylinder housing ends of the cylinders 1 are pivotally journalled around stationary support shafts 10 that are parallel to the shaft 42, i. e. to the pivot axis 40 of the object, and equally spaced therefrom. The axis of the shaft 13, i. e. of the follower body 14, crosses the junction of the free ends of the cylinders.
The cylinders have two end positions and the axis of the shaft 13/follower body 14 may assume four distinct positions that are determined by the possible combinations of the end positions of the mutually connected piston rod ends. These positions are designated 30,31, 32 and 33, respectively. The angular distance between adjacent positions around the shaft 40 is 90°. The pivotal support points for the cylinder housing ends and the pivot axis 40 of the object 43 lie between the maximum and minimum length of the cylinders 1. Since the angle between the piston rods 12 of the cylinders 1 does not exceed 180°, there is no risk that the apparatus will experience dead position locking. The depth of the slot 44 is selected so that the body will be received therein in all positions. The object 43 may be a rotary plate or index plate that in turn supports for instance a workpiece carrier that shall be adjusted to the different angular positions that are mutually separated by 90°.
In fig. 2 is schematically illustrated that the cylinders 1 are controlled by a control device 60, having means 61 securing that the two cylinders 1 are adjusted between their end positions with a time interval for displacing the body 14 between circumferentially adjacent angular positions 30,31, 32,33 that are separated by 90°. The two cylinders 1 can rotate the plate 43 in proper order and in the desired direction between its predetermined angular positions 30, 31,32 and 33 around the pivot axis 40. The cylinders 1 have stable end positions securing that the rotary angle positions of the plate 43 will be stable and exact.
Naturally, the cylinders 1 may be controlled manually. Alternatively the control device 60 may comprise delay means 61 securing that the two cylinders 1 are adjusted with at least one
predetermined time gap. The time gap between the activation of the pneumatic cylinders 1 is relatively uncritical since the cylinders 1 are pneumatic cylinders.
For the above described embodiment, providing adjustment between four distinct positions, it will naturally be possible to replace the pneumatic cylinders by hydraulic cylinders, linear electric motors having two end positions or other force actuators having two distinct end positions. In such cases where the pneumatic cylinders 1 are replaced by hydraulic cylinders or linear motors, or other force actuators, the driving flows and their time relationship must naturally be adapted more critically to each other.
In fig. 3 is illustrated an alternative embodiment of the invention. In this case the object 43 is adjusted between a number of rotary positions 130-134 that are not separated by 90° around the axis of rotation 40. The rotary positions 130-134 may be fixed or may be optionally selectable with regard to their number and/or to their mutual angular separation around the axis 40. In this case it is not possible to use pneumatic cylinders for the force actuators 101. Instead, the actuators 101 may be hydraulic cylinders as very schematically illustrated in fig. 3. However, it will be obvious to the man skilled in the art that other actuators may be used for this purpose, such as the above mentioned linear motors or electromagnets or mechanical drive means such as rack and pinion gears. By employing the appropriate actuators and control unit 160 with delay means 161 the rotary positions, such as the illustrated positions 130-134 may be chosen freely or in steps. The design of the control unit is not described in detail herein for any of the illustrated embodiments. Accepted control technology will be used for designing an appropriate control unit for the apparatus.
In accordance with the invention the object in question may for instance support a workpiece carrier that for processing or other purposes shall be indexable between rotary positions that are spaced exactly 90° around the pivot axis of the object. Another suitable field of application is in waste collection systems of the kind that allow for sorting of different categories of waste at source.
It will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departure from the scope thereof, which is defined by the appended claims.
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