ACTUATOR

Abstract: Actuator for mechanically switching a mechanism (10) between at least two functional positions. The actuator comprises a rotationally symmetric inner rotatable member (23) rotatably journalled by means of an eccentrically located axle (25) and an outer rotatable member (24) journalled eccentrically about the inner rotatable member. It exhibits actuating members which, by changing position, influence the mechanism. The inner rotatable member and the outer rotatable member (24) are arranged to assume different angular positions, in part by turning of the inner rotatable member about its axle (25), thereby causing the outer rotatable member to turn, and in part by turning of the outer rotatable member (24) relative to the inner rotatable member, whereby the change of position of the actuating member is brought about.

Description: Actuator Technical Field: Technical Problem: In conveyor plants for example are found drivi devices which are switchable between a driving state and disengaged state. This switching is done depending upon t presence or absence of conveyed objects at certain poin along a conveyor. For example, the state of the drivi devices can depend on the position of two different senso which, when using conventional technology, requires doub switching devices for each driving device, which is an expe sive solution requiring much space. The object of the present invention is to provi an actuator which is provided to be controlled by means two or more sensors. The Solution: The said purpose is achieved by means of an actuat in accordance with the present invention, characterized the actuator comprising a rotationally symmetrical inne rotatable member which is rotatably joumalled by means o an eccentrically located axle, and, around this inner rotat able member, an eccentrically joumalled outer rotatabl member, exhibiting actuating members which, by changing posi tion, influence said mechanism; by the inner rotatable membe and the outer rotatable member being arranged to assume dif ferent rotational positions, in part by rotation of the inne rotatable member about its axle, thereby setting the oute rotatable member in said rotational movement, and in part b rotation of the outer rotatable member relative to the inne rotatable member, thus causing the said changing of positio of the said actuating members; and by the said mechanis comprising a switching device provided with an element fo switching the switching device between an engaged positio and a disengaged position upon switching of the actuato between a centric and an eccentric position. Brief Description of the Drawings: The invention will be described below in more detai using an exemplifying embodiment with reference to the accom panying drawings, in which Fig. 1 shows a partially broke side view of a roller conveyor provided with actuators i accordance with the present invention; Fig. 2 shows a vie from above of a conveyor provided with actuators according t the invention; Fig. 3 is a view on an enlarged scale of section of the roller conveyor including an actuator; Figs 4-7 show schematically a switching device contained in th roller conveyor and an associated actuator in different actu ating positions; Fig. 8 shows a partially broken sectiona view of the actuator in Fig. 1; and Fig. 9 shows schematical ly a side view of a modified embodiment of a roller conveyor Best Mode of Carrying out the Invention: The roller conveyor, shown in Figs. 1 and 2 as a example of the use of the invention, consists of a larg number of driving rollers 2-7, which are rotatably joumalle in a frame 1, and which are coupled in groups by means of driving chain 8, one driving chain for each group, whic engages a chain wheel provided for each driving roller 9. Each group of driving rollers is arranged to be switche between an engaged state and a disengaged state by means of switching device 10, 11 mounted on one driving roller 3, 6 i each group. When the periphery of the switching device i pressed against, it is arranged so as to switch between a engaged position and a disengaged position and is e.g. of type shown in the Swedish patent 8101243-7 (publication No. 432020), the periphery of which is designed as a press ring, which, at a centric position in the switching device, main tains an engaged position, but, when moved to an eccentri position, switches the switching device to a disengaged posi tion. The switching device exhibits a member which is fix ly connected with chain wheels 12, and another member, wh is fixedly connected with the associated driving roller 3, The chain wheels 12 are in turn connected to a driving mo via a drive chain 14. According to the invention, actuators 15, 16 provided for switching the switching devices 10, 13 by appl ing force against the periphery of the switching devices In the illustrated example the actuators are activated switching them by means of push rods 17, 18, 19, 20, two f each actuating member, each push rod being connected to sensing member 21, 22. Each sensing member 21, 22 is co nected to two push rods, namely, the one push rod of the o actuator and the other push rod of the other actuator. The construction and function of the actuators 1 16 is best seen in Figs. 1, 3 and 4-7. The figures show th each actuator 15, 16 consists of two eccentrically, rotatab joumalled rotatable members 23, 24, of which an inner rota able member 23 is eccentrically joumalled by means of first bearing axle 25, and an outer rotatable member 24 eccentrically joumalled about the inner rotatable member 2 which thus forms a second bearing axle. Mechanically, t bearing is provided by the first axle 25, either by it bei fixed and the inner rotatable body 23 being joumalled on i or by the axle being rotatably joumalled in the frame, f example, by means of a bracket. The outer rotatable memb 24 is jou alled by it being provided with a cylindric through bore or counter bore, which is eccentrically locate The two rotatable members 23, 24 are rotationally symmetric (in the example shown they are cylindrical), and each rigidly joined with a swinging arm 26, 27, which swingi arms are indicated schematically in Figs. 4 to 7 by means dash dotted lines. Each of the two swinging arms 26, 27 arranged for switching between two swinging positions, that there are four different position combinations for ea actuator, as is seen in Figs. 4-7. In the first positi according to Fig. 4, both swinging arms 26, 27 are located a a far end position relative to the corresponding switchin device 10 (in the example shown the swinging arms coincide) whereby the outer rotatable member is located at a distanc from the press ring 28 of the switching device. The pres ring 28, and therefore the switching device, are thus locate in a non-activated position, which normally means that th switching device is in the engaged position, with the corre sponding driving roller 3 being in the driving state. Fig. 5 shows a second position, in which the swing ing arm 26 of the inner rotatable member 23 is swung forwar against the switching device, resulting in the inner rotat able member 23, due to its eccentric joumalling about th axle 25, being swung forward clock-wise, which in turn lead to moving forward of the outer rotatable member 24 which below, is referred to as the actuating member, against th press ring 28 of the switching device. The press ring of th switching device will, however, still not have been moved t an eccentric position, but rather, at most, the actuatin member's 24 periphery just touches the periphery of the pres ring. Fig. 6 shows a third position, in which both swing ing arms 26, 27 are brought forward against the switchin device. Even the outer rotatable member 24 is thus rotate forward about the inner rotatable member 23, which is eccen trically located relative to the outer rotatable member, th inner member, as in the position shown in Fig. 5, being swun forward about its eccentric axle 25, which means that th periphery of the outer member 24, that is to say, the sectio of it located closest to the switching device which forms th actuating member for actuating the switching device, i brought forward additionally a short distance in such a wa that the press ring 28 is displaced by the actuating membe 24 to a position which is eccentric relative to the axis o rotation 29 of the switching device. This eccentric dis placement of the press ring 28 means that the switching de vice 10 is switched to a disengaged position, i.e., in th example shown, so that the driving roller on which th switching device 10 is provided is not drivingly connecte with the driving device (not shown in the drawing) . Fig. 7 shows a fourth position, in which the in rotatable member 23 is swung back to its position shown Fig. 4 by the corresponding swinging arm 26 having been turned to the starting position, whereas the other swing arm 27 remains in its advanced position. The outer rotata member 24 is thereby moved back a short distance in relat to the position shown in Fig. 6, so that the press ring 28 not displaced eccentrically, which means that the switch device is in the engaged position, as in the positions sho in Figs. 4 and 5. In the example shown the driving rolle to which the switching device is connected, is back in t driving position and is arranged to rotate together with t driving device of the plant. Fig. 8 shows in greater detail an example of t mechanical construction of a portion of a conveyor, on whi the device according to the invention may be mounted. shows schematically how the switching device 10 is divid into its two parts, which are arranged to be in either secu driving connection with each other or to be disengaged fr each other. Referring primarily to Fig. 9, but also to Fig. the principle function of a portion of a conveyor, in whi the device according to the invention may be mounted, will described. The roller conveyor shown in Fig. 9 exhibits number of switching devices 10, 11 provided at a distan from each other on certain ones of the rotatably joumall driving rollers 2-7, for example, on every seventh drivi roller, i.e., with six driving rollers between each pair switching devices, the seven driving rollers being connect to one another by means of the driving chain 8 and th arranged so as to be in the engaged position or the di engaged position simultaneously by means of the switchi device provided last in the group of driving rollers. means of this construction the roller conveyor can thus divided into a number of sections which can alternate being switched between the driving position and the no driving position. According to the invention the driving a the non-driving positions are determined not only by t presence of goods, for example, a pallet, on a certain sec tion, but rather switching may also be controlled by an addi tional condition, i.e., the presence or absence of goods on previous section, for example, in the form of a followin pallet 31. Fig. 9 shows the end of a roller conveyor wher the cne swinging arm 26 is not connected to a sensor, but t a unit, for example, a piston assembly 32, which is activate arbitrarily as desired or by means of some automatic device Sensors 33 are arranged one for each section and are locate near the end of each section of driving rollers, but ar placed before the last driving roller 3-6 in each section and they stick up so that, in the presence of the goods i.e., the pallets, they are pressed downwards and are arrang ed so as to rotate clock-wise. (The pallets 30, 31 are sup ported by the rollers 2, 3, 4, 5, 6, but are shown in Fig. as being on a higher level for the sake of clarity.) Thus, when the sensors 33, 35 are not depressed, the actuator are in the position shown schematically in Fig. 4 with th switching devices being not activated and thus in the engage position, i.e., a position in which the corresponding sectio of driving rollers is in the driving state in order to mov the pallets 30, 31 forward. When a first pallet 30 is fe over the roller conveyor and thereby activates only one o the sensing members 33, 35 at a time, forward driving thu takes place the whole time, since the position shown in Fig. 6 is not assumed. When the pallet 30 reaches the last senso 35 and the maneuvering unit 32 holds the swinging arm 36 an the inner rotatable member 23 of the actuator in the advance position, the switching device 10 will switch since the sen sing member 35 will then swing from the second position, shown in Fig. 5, to the third, activated switching position, shown in Fig. 6, leading to the section of the driving rol lers 4 and 5 and the intermediate driving rollers, as well a the driving roller 6, becoming disengaged, whereby drivin action will cease. At the same time as switching of th sensing member 35 takes place the one swinging arm 26 of th actuator 15 swings over, which, however, does not lead t switching of the preceding section of driving rollers, whic are driven via the switching device 10, into the activa state but rather this section will be in the driving st until the following pallet 31 switches the sensing mem 33. This switches the swinging arm 27 and thus the ou rotatable body 24, so that the actuating position shown Fig. 6 is assumed and the preceding section of driving r lers including, among others, the driving rollers 2 and will be disengaged. This means that the two pallets 30, 31 will not stopped by some stop dog so that they stand and skid on underlying driving rollers. The actuator in the precedi section, etc, is thereby switched in a corresponding mann so that the pallets are stopped as they arrive in the que formed. As soon as the first pallet 30 is removed from t place shown in Fig. 9, for example, by it being lifted aw by means of a fork lift or by being pushed to the side onto transversely oriented conveyor, the sensing member 35 switched, which switches both of the actuating devices 15 a 16 to the driving position so that the following pallets a the remaining pallets are fed forward until the pallet 31 turn activates the sensing device 35, is stopped, and so o If it is desired to move the first pallet 30 forwards whi the sensing member 35 is actuated, the maneuvering unit is switched so that the corresponding swinging arm 26 swung from the position shown in Fig. 9, whereby the furthe most section of driving rollers is engaged in the drivi position. The invention is not limited to the exemplifyi embodiment described above and shown in the drawings but m be varied within the scope of the following claims. T actuator may for example be switched in a different manne The power transmission of the mechanical sensing members m for example be done pneumatically or hydraulically by arran ing a piston and cylinder system, e.g., of the type found brake systems for vehicle brakes. Sensing may even be do electronically or optically by means of position switche photocells, or the like, which, via motors or electromagnet turn the rotatable members in the actuators. The switchi devices may have a different construction than the one de scribed in the above cited patent. What is essential is tha switching can be accomplished by the actuator of the chose type being able to move against or away from an element o the switching device, thereby providing switching between th engaged and the disengaged positions.

Claims: Claims : 1. Actuator for mechanically switching a mechanism (1 between at least two functional positions, c h a r a c t r i z e d by the actuator comprising a rotationally symme rical inner rotatable member (23) which is rotatably jou nalled by means of an eccentrically located axle (25), an around this inner rotatable member, an eccentrically jou nalled outer rotatable member (24), exhibiting actuati members which, by changing position, influence said mech nism; by the inner rotatable member and the outer rotatab member (24) being arranged to assume different rotation positions, in part by rotation of the inner rotatable memb about its axle (25), thereby setting the outer rotatab member in said rotational movement, and in part by rotati of the outer rotatable member (24) relative to the inn rotatable member, thus causing the said changing of positi of the said actuating members; and by the said mechanism (1 comprising a switching device provided with an element (2 for switching the switching device between an engaged pos tion and a disengaged position upon switching by means of t actuator (16) between a centric and an eccentric position. 2. Actuator according to claim 1, c h a r a c t r i z e d by the inner and the outer rotatable members (2 24) each being connected to a swinging arm (26, 27), t swinging arms being arranged to assume different swingi positions, thereby bringing the said rotatable members wi them. 3. Actuator according to claim 2 , c h a r a c t e r i z e d by the swinging arms (26, 27) and thus the rotat able members (23, 24) being provided to be switched betwee the following positions: a first position with both rotatabl members (23, 24) rotated away from the mechanism (10); second position, in which only the inner rotatable member i rotated against the mechanism, whereas the rotational posi tion of the outer rotatable member is maintained; a thir position in which both rotatable members (23, 24) are rotate against the mechanism; and a fourth position, in which onl the outer rotatable member (24) is rotated against the mecha nism, whereas the rotational position of the inner rotatabl member is maintained. 4. Actuator according to claim 1 included in a rolle conveyor having a plurality of rotatable driving rollers (2 7) which are connected as sections to a driving device via switching device (10) for each section, the sections of driv ing rollers being arranged to be switched between a drive state and a disengaged state depending on the presence o goods (30, 31) on the respective section and the precedin section, the presence being sensed by means of a sensin member (33, 36) provided for each section, c h a r a c t e r i z e d by the said actuators (15, 16) being provided a each switching device (10), by the sensing member (33, 36) o each section being arranged, in the presence of goods on certain section, to swing in part the one swinging arm 26 o the actuator belonging to this section and in part the secon swinging arm (27) in the actuator (15, 16) belonging to th following section.

Inventors: SIREFELT LARS, SIREFELT, LARS
Applicants: SIREFELT LARS, SIREFELT, LARS
Application year: 1988
Main classification: B65G13
IPC codes: B65G47