Adjustable gear assembly

Posted by Fun ka maza on 11:15 with No comments
Adjustable gear assembly

An adjustable gear train is disclosed in which play in a gear train meshed conical formation is accommodated by one of the gears of two radially spaced coaxial parts which are axially movable with respect to each other, one of the parts being sprocket and the other of the parts that form an axis of the toothed part.

Background of the Invention
1. Field of the InventionThis invention relates to gear trains, more particularly, to an adjustable bevel gear train including a plurality of intermeshing bevel gears.
Two. PriorGear trains through a plurality of intermeshing bevel gears are known in the art. A particular application is in the industrial robot in which the spindle drive of the hand is through a drive train that controls the point of load application captured from a relatively remote point. Power transmission is, therefore, through shafts and gearboxes. In such construction, relatively large play may occur at the point of application of the load as a result of gear wear occur during periods of use. In order to obtain the original precision of the robot, the game has to be corrected.
Gear backlash elimination so far has been accomplished through the use of removable shims or inserts positioned within the gear train. When a bevel gear train has used one of the bevel gears is provided with axial wedges interposed between the equipment and installation in the home. Axial these wedges can be changed in such a way as to change the effective axial position of the gear, thereby allowing the game to be addressed.
However, in order to change the axial position of the gear by means of a positioning wedge, it is necessary to disassemble the unit broadly. This removal takes a considerable period of time and must be performed by highly trained staff. Moreover, since the wedges should be placed after removal equipment fit, there is no guarantee that the technical adjustment is correct. As a result thereof, when individual game fixes often extends partly due to lack of time in which to make the correction, and therefore, the industrial robot is operated with an increased play and results in increased inaccuracy so that the share of rejected parts of the products handled by the robot increases.It would therefore be an advance in the art to provide a bevel gear train which is easily adjustable for the purpose of eliminating backlash between gears.
 Embodiments of the inventionIt is a primary object of this invention to provide a bevel gearing adjustable in the time required for the elimination of play is reduced while the accuracy of the gear train is in general carried out in a uniform plateau.Moreover, it is an object of this invention to provide a bevel gearing which is adjustable constructed such that the adjustment in order to eliminate wear caused simplifies game which requires a relatively short time so that production require only short breaks for maintenance of industrial robots equipped with the gear train.It is a further object of this invention to provide such a gear train of bevel can be set adjustable moderately trained personnel.The above objects are met by the present invention by constructing at least one axis of the gear train of two separate parts radially. A party is a part of the gear tooth and the other is the shaft portion. The toothed portion is axially displaceable in the shaft portion and is therefore movable relative to the coupling gear in order to alter the teeth mesh. In the preferred embodiment illustrated, there is a threaded connection between the two parts such that relative rotation of one part with respect to the other, will cause an axial displacement. Furthermore, in the preferred embodiment, the two parts are held together by bolts extending axially which are equally spaced circumferentially around the axis of the two parts such that an adjustment increment may be one or more bolts spaced angular rotations . To provide for fixing other parts of the industrial robot for adjustable gear end through the intermediary of the pin attachments equally spaced, equal in number and spacing of the axially extending bolts ensures that an adjustment for the game will not result in any misalignment of the parts in the output end of the gear train.Other objects, features and advantages of the invention will become readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be made without departing from the spirit and scope of the novel concepts of the disclosure, and in which:
. Figure 1 is a fragmentary cross-sectional illustration of a set of bevel gear train of the prior art.. Figure 2 is a fragmentary cross sectional view of a bevel gear train modified according to this invention.
An adjusting bevel gear train standard technique is illustrated in cross section in FIG. 1. In such a configuration, there is provided an axle unit 1 through the pinion gear bevel gear 2 to intermediate 3 which is constructed as a double gearwheel. Leads proceeds through the mesh of the teeth 3 and 4 to the drive gear and the shaft 5. Unit 5 is constructed as a bevel gear having threaded sockets for fixing gripping devices such as forceps or vacuum gripping members. Play occurs due to wear in the mesh between the teeth 4 and 6 will allow rotation of the output end of the gear train in relation to the input end so that the tool is connected to the unit 5 can be turned off alignment with the position of the shaft 1. In order to accommodate game wedges 7, 7 'are provided. The height of the wedges may be altered in accordance with specific methods so that the shaft 5 is constructed as a bevel gear is placed closer to the intermediate bevel wheel 3 which in turn can therefore be positioned more near the pinion 2. This translates into a decrease in clearance between teeth 4
In order to adjust for the game, in the existing building, wedges 7 and 7 'to be removed first and then
successively replaced by new size supplements. The required thickness of the wedges of substitution has to be determined in relation to existing chocks 7, 7 'so that existing chocks are effectively reduced in thickness until it has obtained an ideal positioning. Since the replacement of wedges occurs after unit 5 has been removed, it should be clear that the exact choice of the new spots is often a matter of conjecture.Often, in order to achieve the correct final positioning of the unit 5, the wedges must be replaced up to 6 times. The process takes about two hours and can only be performed by highly qualified personnel. Even in that case, the correct adjustment of the position of the unit 5 is not assured.As illustrated in the figure. 2, according to this invention, adjustment can be provided in a gear train like by replacing the unit 5 with a unit axially adjustable. In such case, the unit can be built axially adjustable in two parts, 10 and 11. The bevel gear teeth formed on an axial end of part 10, whereas the part 11 forms a shaft portion 10 and provides for attachment of the tools to be manipulated by the gear train.The two sides are preferably joined together by meshing teeth 12 have a very fine pitch. Thus, the rotation of one member relative to the other member the two members will move axially relative to each other. The parts can be connected axially through bolts 13 which can be received in bores of a slightly larger size so that the torque transmission is due to friction of the thread 12.Robot tool is connected to member 11 via threaded holes 14. The number of bolts 13 is equal to the number of tapped holes 14 and pitch angles of the two bolt circles are also identical.It will be appreciated that adjustment of the gear train can now be delivered through the simple expedient of removing the bolts 13 and the rotation of member 11 relative to member 10 such that the gear member 10 moves axially towards the intermediate gear 11 until the game is reduced to the desired degree. Because two members retain their connection to each other, the game can be measured during this adjustment process.After obtaining the desired playback condition, the bolts 13 are reinserted. It will therefore be apparent that the adjustment is small as possible a rotation which is equal to the angle of the bolt circle. Therefore, if using four screws, one quarter rotation would be the minimum. Due to the fine pitch of the threads 12, however, the need to make an adjustment of rotation determined by the angle of separation between the bolts 13 is not problematic.After insertion of the pins 13 will be seen that the alignment of the shaft 1 will continue gripping tool because equal positioning of the threaded apertures 14.Of course, it will be apparent that other modifications can be made in this design. For example, the transmission of torque could be via bolts 13. Furthermore, the torque transmission can be provided by using driving pins or similar.Is an important factor in the constructions according to this invention, the gears do not have to be separated from each other in order to provide for adjustment. For example, it is not necessary to remove the screws 8 and the cover 9. You can, therefore, be seen that play in the gear train illustrated, can be adjusted quickly even with the help of relatively untrained personnel.Although the teachings of my invention herein have been discussed with reference to the theories and specific embodiments, it should be understood that these are by way of illustration only and that others may wish to use my invention in different designs or applications.


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