Bearings – Linear bearing – Roller bearing
Reexamination Certificate
2000-03-10
2002-01-08
Hannon, Thomas R. (Department: 3682)
Bearings
Linear bearing
Roller bearing
C384S045000, C029S898030
Reexamination Certificate
active
06336744
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a linear drive, comprising primary part or a secondary part arranged on a slide block, wherein the slide block is movable on a guide-rail system, as well as a stationary secondary part or primary part, as the case may be, which operates together with the primary part or secondary part arranged on the slide block in such a way that the slide block is movable on the guide-rail system.
Furthermore the invention concerns a process for assembly and dismantling of this linear drive, wherein this process in this case in particular refers to the assembly or dismantling of the primary part or secondary part onto or from a movable slide block.
Prior art linear drives are wide spread in engineeing. For example they are used in machining centres or machine tools, in order to move and position the lathe spindle at higher speed or with greater precision. The secondary part in such instances comprises an arrangement of magnets having alternating polarity. The secondary part is for example arranged to be stationary and operates in conjunction with the primary part. The primary part comprises an electromagnetic drive, in which the current conduction is used to generate a magnetic field, which operates in conjunction with the magnetic field of the secondary part so that the slide block moves on the guide-rails.
BRIEF SUMMARY OF THE INVENTION
The invention is described as follows such that the primary part is located on the slide block and the secondary part is stationary. However the invention is not limited to this arrangement. In the same way it is possible to arrange for the secondary part (ie the arrangement of the magnets) to be movable on the slide block and the primary part to be stationary.
One or more guide-rails may be arranged, for example, as the guide-rail system. To achieve higher efficiency the gap between primary part and secondary part may be designed to be relatively small. This gap ultimately defines the drive efficiency and with this also the power consumption for a movement of the system.
With an arrangement such that the movement travel of the linear drive runs in a horizontal plane, the primary part is located for example beneath the slide block. The lathe spindle, eg a cutting tool machine, is constructed on the slide block. The primary part in this case is connected to the slide block with fixing means, for example with screws. The total assembly attains a considerable weight of up to several tonnes. If the primary part is then to be serviced or to be changed on account of tool wear, this can pose some problems to the fitter. The primary part is constructed beneath the slide block so that this cannot be reached easily. Also it is not always possible to lift up the machine tool associated with it. At the same time it should be noted that in addition to the weight of the slide block and the mounted assembly the magnetic attraction of the secondary part still acts upon all magnetisable elements, which increases the force which would be needed to lift off the guide block from the guide-rail system.
The costly dismantling of the linear drive leads to long maintenance times accompanied by long down-times of the machine tool, which is usually undesirable.
The invention had as its task to improve a linear drive as initially described, to the effect that the time for changing the primary part, and with this the down-time of the plant fitted with the linear drive, is reduced.
The invention here assumes as a starting point a linear drive as initially described, ie a linear drive comprising a primary part and a secondary part, one of which is mounted on a slide block and the other of which is stationary. The invention proposes a that a spacer block is arranged between the primary part or the secondary part and the slide block, which is able to be then from the slide block when dismantling the primary part or the secondary part and the distance between part and secondary part is thus increased. In the gap so formed a means of transport is introduced, upon which the part or the secondary part is lowered and then moved out. From this the process also arises according to the invention for dismantling a primary part or secondary part from a slide block on a movable guide-rail system, wherein a spacer block is arranged between the primary part or the secondary part and the slide block and the primary part or secondary part is held onto the slide block by a means of fixing, which are freed for dismantling so that the spacer block is able to be taken off and the primary part or the secondary part is then moved against the slide block by the fixing means or other positioning means, whereby a gap arises between primary part and secondary part so that a means of transport is arranged in this gap and the fixing means of the primary part is released completely in order to move the primary part away from the slide block using the transport means.
On account of the high magnetic force acting between the primary part and the secondary part, care should be taken that primary and secondary parts do not come into contact with one another or lie flat on one another, since a movement of both elements relative to one another is then only possible with high energy cost, or is impossible. The transport means introduced into the so formed gap consists in this case most favourably of a non-magnetic material and acts as spacer between both of the magnetically attractive elements. On account of the residual gap there will be no adhesion of the two elements, both elements remaining movable one with another.
In the case of the process for dismantling according to the invention the spacer block is preferably held on the slide block by the same fixing means which also fix the primary part to this. Next the spacer block is extracted in order to create space between primary part and slide block, which, after the primary part is moved relative to the slide block, serves to increase the gap between primary and secondary parts so that a useful gap arises.
At the same time it is not necessary that all fixing means are involved, rather it is possible that only a few fixing means serve to fix the primary part to the slide block. At this point the fixing means are at first opened a little and through this the primary part lowered by a few tenths of a millimeter or moved against the secondary part, in order to remove the spacer block sideways. If the spacer block is removed, the primary part is again moved against the slide block with the help of the fixing means, which are then tightened again, or by further means of assistance, eg., positioning means, as a result of which the gap forms. For the idea according to the invention it is not critical that a noticeable gap of a few millimeter remains in the opening condition; it is however essential for the idea according to the invention that the gap between primary part and secondary part is increased by the extraction of the spacer block. In tis way it is also possible that the distance between primary part and secondary part is virtually zero.
The arrangement according to the invention is however limited not only to a process for dismantling the primary part but also concerns also in the inverse sense a process for assembly of a primary part or secondary part on a slide block which is movable on a guide-rail system, wherein the part or secondary part is positioned on or adjacent the transport means under the slide block, wherein the primary part or secondary part is held by the fixing means or positioning means of the slide block and the transport means is removed from the primary part or secondary part, wherein the primary part or secondary part is then removed from the slide block slightly by the fixing means or positioning means, in order to introduce and arrange the spacer block between primary part and slide block and subsequently the primary part and slide block are connected firmly together with the fixing means.
The invention is not limited to the arrangement of the primary part or secondary part above or at the si
Rehm Karl
Stoiber Dietmar
Hannon Thomas R.
Jacobson & Holman PLLC
Siemens Linear Motor Systems GmbH & Co. KG
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