AU2920502A - Screw drive method and apparatus - Google Patents

Description

310- 3-02:1:5AM;DAVIES COLLISON CAVE 5/ 29

.AUSTRALIA,

PATENTS ACT 1990 DIVISIONAL, APPLICATION NAMEl OF APPLICANT:' Flow International Corporation ADDRESS FOR. SERVICE: DAVIES COLL ISON. CAVE.

IPatent Attorneys M6.1b66ine, 30010.

INVENTION TITE: f"IScrew drive method and apparatus" The following statement is a full description of this invention, including the best method of perform~ing it known to us: ______RECEIVED TIME-..30. -P RI NT TIME-. 2. APR. -11 :16 3-02;11:52AM;DAVIES COLLISON CAVE 6/ 29 SCREW DRIVE METHOD AND APPARATUS This application is a divisional of Australian Patent Application No. AU 31126/99, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD This invention relates to improved screw drive devices and methods for their operation.

BACKGROUND OF THE INVENTION Screw drive mechanisms for converting rotational motion to linear motion are employed in a variety- of applications, including cutting, machining, Swoodworking, and precision manufacturing, such as in silicon chip fabrication. Screw Sdrives.may offer improved reliability, speed, and accuracy over other types of drives.

such as belt drives.

iiConventional screw drive mechanisms, such as the device 10 shown in h 1 artial ross sectii nrar. nclude .:ad d .it h e.a :2 setat ivenjlea pit Poitiooithe hreaed rouf s m viig aadbearing channel 16 opposite the helical thread 12 of the threaded rod 11. A plurality of balls 18 are positioned between the load-bearing channel 16 and the helical thread 12.

SEnd caps 20 at the ends of the nut 14 contain ball retunm passages 22 that are aligned with the load-bearing channel 16. The nut 14 may be rotated relative to the threaded rod 11 (or vice versa) to impart linear motion to either the nut or the threaded rod. As the nut 14 and the threaded rod 11 rotate relative to each other, the balls 18 rotate relative to the nut and the threaded rod to reduce friction therebetween.

Conventional screw drive mechanisms may also include a housing 24 positioned radially outward from the nut 14 and coupled to. the.nut with support bearings 26, allowing the nut 14 to rotate freely within the housing 24. The support bearings 26 may include an inner race 32 adjacent the nut 14, an outer race 34 adjacent the housing 24 and a plurality of balls 19 between the inner race 32 and the outer race 34. Seals 28 are installed at opposite ends of the housing 24 to contain a lubricant between the housing 24 and the nut 14 for lubricating the support bearings 26. The housing 24 may then be attached to a device that is moved linearly relative to the -RECEIVED TIME 30. MAR. 13: 06 -PRINT TIME 2. APR. ,11:16 -UZ;11:52AM;DAVIES COLLISON CAVE 7/ 2 9 .2 threaded -rod: 11. For qIXaMplC.-the housing ma, be attadcd-to a tabl fo'r POsitioning a' machineabi'c'workpieee. or to a support arm for positioning a waterjct cuttirit nozzle.

Convenionadl scrcw drive mech'anisms may have several disadvantagc.-- For. example, aftcr extended use, the als9anthinner and outer-rcs3 ad3o the suppbrt beari ngs- 26 may wear. causing these :components to fit looscly toge~ther and resulting In reducd 'oto oethe position.o h osn 4rltv otetrae rod 111'. Where thc, housing: 21is coup led to a-watejtcutn nzlth nbiiyt accurately: control the position of* t11C housing may* result- in inaccurate cuts. 'Another disadvantage of conventional. screw drive mechanisms is that it may be difficult to service individual components of -the mechanism without disassembling the entire mechanism.

:One. approach to 'addressing wear in the com ponntofhent1ha been to preload the balls 18K.For example., U.S. Patent No. 5,263,381 to. Shirai. discloses.

Sapplying a preload force to the balls. I 8,:to. eliminate axial gpbew eeblsth helical thread. 12 -and thie load-be aring chiannel 3i6. ,"Siial' TSatet No. 5 S.Oi.64 Ts'ukaa dicoe rla orce for rtdueizng.ibiratioh n -a a. re a'd.f. fp- o sl§idingmeri eraJn' rail. 666vriin of the: deices discussed ibieades h rbe o os i ::*'between the housing. 24.and the. niut 14 -caused by wear in the- support: bearings2 26..I fact.. Paxent No. w,4,7 To Takuno et al. discloses hat preloading face-to-face angular contact bearings may heat the' bearin'gs, causing themn to seize.

SUMMARY OF THE INVENTION The present invention is directed to methods and apparatuses for converting between rotational and linear motion with a screw drive mechanism. In one embodiment, the apparatus includes a threadcd rod having a helical thread, and a nut disposed about the threaded rod and rotatable relativ e to the threaded rod. 'The'nut -has a' channel aligned with and radially outward from the helical thread, and further has a 'plurality of balls between the helical thread and the channel. The apparatus may further include a drive shaft connected to the nut, and disposed about the threaded rod. and a housing disposed about the drivcshaft. At least one support bearing having an inner -RECEIVED TIME-3O. MAR. PRINT TIME=. 2. APR. =11:16 U f I 1 04 MM;L)MV I COLL I SON CAV E 8/ 29 race connected- to the drive shaft 'and an outer race conriected to. thc h~usigalw h housing to move -linearly as the. nut anid drive shaft rotate' relative toncaohrA retaining mfcmiber may be remrovably attacdhed' to. the drive shaft to. apply an ajstable force on- the' support bearing in a direction generally prle oalniuia xso h threadcd* rod.in one embodiment, the. retaining member threadably engages the drivc shaft.* Ti -another cmbodi en;teraiigem r eng age the nut. and the'dri ve saf may be'elimyinated. In s till another embodiment 'thc housing, may include two support bearings, each of which is compressed by the retaining member.

0 Jn still a, further embodiment, 'the apatsmyildeeas on opposite sides of the support-bearing. The seals fori reservoir to maintain a supply of.

lubricant 'about. the -support bearing.- The lubricant May also be deposited on; the threaded rod through a weep port provyided in the drive'sh'aft sio as to lubricate, thc nut..', 'In yet a, further emnbodiment, the threaded rod m~ay include two nuts,' each 5 culdto the other ad' cup e, to. the. housing :with' ,aid-ppon'bcaring.. j.e 'etaihing em eroalyI.

member~~ ma ermvbyatced-to the housing to applya 'adjustab le: axial 'for*e t elemints ofboth the-i suprt beansadus BRIEF DESCRIPTION OF THE-DRAWINGS figure 1 is a partial cross-sectional view of a screw drive in accordance.

with: the prior art.

Figure 2A is an end view of a watcrjet cutting machine having a single screw drive apparatus in accordance with an embodiment of the invention.

Figure 213 is side view of a waterjet cutting machine having two screw drives in accordance with another-embodiment of thc invention.

Figure 3 is a cross-sectional -side view -of the s~rew -drive apparatus shown in Figure 2A.

Figure 4 is cross-sectional side view of an apparatus in accordance with another embodiment of the present invention having a single support bearing and a retaining member threadcdly engaging a nut.

RECEIVED TIME=3. MAR PRINT TIME.. 2. APR. =11:16 3-O 2 ;11:52AM;DAVIES COLLISON

"'CAVE

4 9/ 2 is cross-sec ional side view ofanpprusiacoaneit still another embodiment- of the present invention ha ving.,two. support bearings aind a reCtaining member'xhrcadedlyegina houig6 Figure 6 is a-cross.-sectional sidc -view of an apparauin accordance with Syet, another. embodiment of the invecntion' having. a singe support erig Figure.7A isacross- sectioinal 'view. of an.appara tus, having two nuts Joined by a coupling mcember in. accord*nce with aoher- ebodienofteivno.

Figure 7B is* a cross-sectional'side. view, of an appararus havingt two'nuts joined by a rigid 'coupling member in accordance with still another embodiment of the 0 .0 0 0 0.

DETAIL.ED DESiCRIPTION OF THE INVENTIO'N Figure. 2A is an, end view of a,.waterjet cutting apparatus, I10 having: a, beam 101. movably connected: to a support12 h beam'10 includes anzl 0 that direc't' a hnigh ,'pressuzre waterjet .'to a -rp *~it~ebJ I0may~be attache to'a~snesipr 04t -ih p'ulew. belw:8P The beam 15 a shw sign suppor 10 with the be10 orm at how inFigre2B. t5 e my be. attached to' a pair: of'spaced-apart Supports 102 with. a 'corresponding. pair of screw drive apparatuss 11.'Referring to Figre and M. the apparatus.. 110 may include a threaded rod .1ll that.extends perpenldicujar to the plane: of the figUres .a nd mnay b.e connected to the- support 102 at each nd withabace 03 ,shown partially cut away. 'The apparatus '110 may further include. a nut 11 4 -that engages the- threaded rod I111 arnd is connected to the beam. 101 with ahuig14 The nut 114 is rotatably driven by a pulley 140 connected with a belt 104 to a. drive means 160, such as a mot or. As the drive means 160 rotates the pulley 140 and the nut 114, the beam 10 1 is driven linearly perpendicular to the plane of Figures 2A and 2B to cut a pattcrn in the workpiecc: 106.

Figure 3 is a cross-sectional side view of the apparatus 1 10 shown in Figure 2A. As shown in Figure 3. the threaded rod Ill has, a helical thread 112 that engages a corresponding spiral channel in the nut 114, as descri bed above with reference to Figure 1. The nut 114 is coninccled to the pulley 140 and to a drive shaft -RECEIVED TIME-30, MAR.] J3: PRINT TIME= 2, APR. 11: 16 2-02:11 :52AM;DAv1ES COLLISON &CAVE 10/ 23 136 w ith Pulley bolts 142.- The pulley bot 4 x e d t r u h f r 'otholes 1 4 i the pulley..140.'through second bolt holes 146 in the nut 114. andcin'gagc threaded hole 148 in a, flange 13-at8 of the d'rive shaft -136. Accordinlteplybos14cnet the.-pulley: 140, thc. nut. 114, and, the drivc shah .136 'i'n a general ly rigid' manncr. The S drive'shaft, 136 is co ncentric with the'threaded rod IlI, 3.and has- an nuus13houg which the. threaded rod: I I extcnds.* .The. housing6 124 icoenrc withbt h threaded rd. 11 anfd th d'rive sha-ft -1'36 an'd'has a'passageway 1*3'0 through which the threaded rod I111 and the drive shaft 136 extend.

First and second spaced apart support bearings 126 (shown in Figure 3A as 1 26a and 126b) are positioned within the passageway 130 between the, drive shaft, 13 6 and the housing 124. Accordingly. the. housing .124 may. include a bearing divider 156..having a first laea ae18 dacent the. first support beaingh 1.26 a and as second lateral face I S58b opposite. the',fhis lateral 'fade l56a: and. adjacent*, the ksecond- support bcaring' 1 26b. The support bearings 12 ayb sae aat yadance sufficient to IS prevent. the housing. 1.24- fro rocking orcain- reIv tone ''1nt the;,supp6ntbearin'gs 12'6' !may iric ude.a 'uaznac ~nshavn :oute r rac 134 adjacent the housing'.124, -an inner rae1-32 adjacent the drive s haft I 36, and 'balls 3,19 be tw een -the inner'and'outer races. -In' other .embodiments, "the balls 1.191 may be replaced with rollers, such -as .tapercd rolilers. .In stillJ further embodiments, 'the.

20 support bearings. 126 may include other types of bearings- that smlryaowrotational.

motion of the drive shaft 136 relative to the housing 124.

A retaining member 150 is removably connected to the drive shaft 136 opposite the flange 138. In one embodiment, shown in Figure 3A, the retaining member 150 may include a locknut having internal threads 152 that threadedly engage external threads 154 of the drive shaft 136. In other emibodimnens, other means may be used to movably engage the retaining memnber 150 'With the'drive shaft 136. A spacer 157 may be positioned annularly about the drive. shaft 136, between the retaining member 150 and the second support bearing 1 26b. As the retaining member 150, is moved along the drive shaft 1 3 6, i t imparts a compressive force through the spacer 157 PRINT TIME-..~ 2. APR.-..11: 16 3

-O

2 ;12:OOPM;DAV1ES COLLISON &CAVE A# A-l 6 to the second support. bearing 1 26b *in the direction generally along tie axis of* the threaded rod Ill..

Alternatively, the -spacer.1.57 may be formecd integrally with the retaining member ISO, which' then- contacts the second' support bearing 126b directly, 'as discussed below with respect to Figures and 5. Ineithecr casc. as the retaining member .150 isadjustably tightened the second supor bern '26b ma e rladdo comrrpressed'between tihe retiinirij mcmb er I.10 and the second bearing divider I 56.. Simultaneously, the first support bearing 126a may be compressed between the flange 138 of the drive shaft 136, anid the first lateral face 158a of 'the bearing divider 156. Accordingly, both axial and radial gaps between the components of the support bearings 126 may be reduced.and/or elim inated as h eann rene :I SOis tightened.' In an alternate. embodimnent, the- outer ,races- 134. of, the suppolrt bearings: 126 may. be rigidly mounted to the housing 124. for example with epoxy. or weldrnents.

1) s t only ,thie 232e an-tebalsd- ncbri tighened An dvanage f tis arrangerent,) sthat tmyeiiae h'edfrte bcani divider 156.: the bearing divider 156 mhay'be ovrey it. allows the support. bearings 126 to be more easily' removed 'for seicg or replacement.

The apparatus 1.10 may also include two seals 164 shown in F igure 3. as', 1 64a and .1 64b) disposed within- the passageway 3 0 at opposite ends thereof One seal 1 64a sealably engages both an outer surface 168 of the flange 138 and an imner surface.

166 of the housing 124 toward the first support bearing 1 26a. The other seal 1 64b sealably engages both the spacer 157 and the inner surface 166 of the housing 124 toward the second support bearing 126b. A grease reservoir 170 may be formed within passageway 30, and may be defined by the seals 164, the housing inner surface 166, the spacer 157, and an outer surface of the drive shaft 136. The grease reservoir 170 may be filled with grease or other lubricants through a hole 172 in thc housing 124 with a conventional grease fitting 174. Lubricating grease may then flow from the grease reservoir 170. through a weep port 176 provided in the drive shaft 13"6 and to the TIME=3.MAR.-..13:09- PRINT 2, APR_...i1: 19 3-02;12:00PM;DAVIES COLLISON CAVE A- 12 7 threaded rod 1ll. Accordingly, both the nut 114 and the support bearings 124 may be lubricated as the nut 114 and the housing 124 traverse back and forth along the rlueaded 'rod 111.

In operation, a preload force may be applied to the sup p p .].26 5 by tightening the retaining member 150 until .it biases the first support bearing 126 against the flange 138, and the second support bearing 126b against the bearing divider 156. The nut 114 may then be rotated to mriove the housing 124 linearly along the threaded rod 111. The retaining 'member 150 may be subsequently tightened or loosened to vary the compressive forces on. the support bearings 126, or the retaining member may be removed to access the support bearings 126.

Alternatively, the threaded rod III, rather than the nut 114. may be rotated, thereby driving the nut and providing the desired rectilinear motion of.housing 124 along threaded rod Ill. However, as the length of threaded rod 111 and/or the angular velocity of the threaded rod increase, the threaded rod may oscillate in an 1 d e s ra v e o a n I: undesirable manner. Inaddition he ieaded rod1 I ma have moe inertia tha e nut 114 .and Ia r equire oreo to rtt F erothapatu10 wi be stiffeir.if the threaded rod is fixed at both ends. it may therefor' bepreerable in waterje t cutting tool devices to rotate the nut 114as discussed above.

.An advantage of an embodiment of the apparatus 110 shown in Figures 2A-3 is that the support bearing 126 may be easily preloaded by tightening the retaining member 150. The retaining member 150 may be tightened without disassembling any of the components comprising the apparatus 110. A further advantage is that the housing 124 may be removed (by removing the retaining member 150) to gain access to the support bearings 126 without disturbing the nut 114 or the pulley 140. Accordingly, the apparatus 110 may be easier to service and maintain than conventional devices in which the support bearings and thenut are integrally coupled. Yet a furtheradvantage is that elements of both the support bearings 126 and the nut 114 may be lubricated from a single reservoir. Still a further advantage is that the support bearings 126 and the housing 124 may be manufactured independently of the nut 114. Accordingly, users requiring a nut and support bearing in combination need not be restricted by the limited RECEIVED TIME 30. MAR., 13:09 PRINT TIME= 2. APR. 11: 19_ 3-02;12:00PM;DAVIES COLLISON CAVE A- 13 array of such.combinations, but rather may combine a housing and a sipport beariig with any number of nuts. Furthermore, the support bearings 126 may have a non-linear stiffness such tha as the load on the bearings increases. the stiffness of the bearings increases. Accordingly, by preloading the support bearings 126, the stiffess and, Snatural frequency of the apparatus 110 may increase, improving the response of the system to vibrations.

Figure 4 is a cross-sectional side view of a screw drive apparatus 210 having a single support bearing 226 disposed in a passage 230 of a housing 224 in accordance with another embodiment of the invention. The support bearing 226 may be a cross-type bearing having an outer race 234 and a split inner race 232. Balls 219, or alternatively rollers, may be positioned between the outer race 234 and the inner race :L 232. One endof the outer race 234 may be positionedadjacent a retainig ring 259 that is received in a corresponding slot 260 in the housing. One end of the inner race 232 n may be positioned adjacent a bearing flange 288 that extends radially outward from a positioned against a .retaining member .250. The retaining member 250 has internal threads 252 that threadedly engage a threaded portion 278 of the -nut 214. As the retaining member 250 is tightened against the support bearing 226, a preload force is adjustably imparted to the support bearing 226, compressing the support bearing against the retaining ring 259 and the bearing flange 288. Alternatively, the outer flange 234, rather than the inner flange 232, may be split and the retaining member 250 may engage the outer race 234.

'An advantage of the screw drive apparatus 210 shown in Figure 4 when compared with the apparatus 110 shown in Figure 3 is that it may be simpler to construct and maintain because it eliminates one sutpport bearinig and does not require a drive shaft 136. Furthermore, the passage 230 through the housing 224 may be more accurately machined because it includes a single bore rather than two opposing bores that are separated by a bearing divider 156 (Figure 3) and that may be difficult to align with each other. Conversely, an advantage of the apparatus 110 is that the two support ahrha~h .ne .'ng 232 .a .e li an .h •eann .ebe a t eou e rac RECEIVED TIME 30. MAR. 13:09 PRINT TIME, 2. APR. 1 1: 19 FESEnd3O- 3 -02;12:OOPM;DAVIES COLLISON CAVE A# A- 14 baings- 2 6 -may-morc securciy support-the--housi'ng- 1-24-rltv ctcrrae rod I111.

Figure J s a cross-scctiona.Lside 'view% of a screw drive apparatus'.31-0 having- a retaining member 350 .that t hreadal enae '*threaded' porin34o 324., The housing 324 is positioned. concentrical ly about'a. nut 314.. which.-is in t.urn positioned "concentrically about the 'threaded-rod 1:11, generally as discussed abovewith reference to Figure The rtiigmember 350, 'nut 314 :and *housing 324.

together with a seal, 364,7 define a grease reservoir -370 that operates in a 'manner generally similar to that discussed above with reference to figure 3.

As the retaining member 350. is adjustably lightened, it impanx. an axial force to the second support''bearing 1 26b, which in turn imparts an,.axial force to the- .first'support bearing: 126a via a sliding bearing -divider 356., An. advantage of the sliding bearing di'vider 356,when compared to the. fixed *bcarng. divider 156 discussed'above with reference. to Figure 3. is that it may'accommo~date bearings having a* variety of axial igure p j6 is,- a cross-sectiona sdviwoascedreapraUS40 aigasnl' bearing 4 :p k6 ajcet Ai *haig' ngesuppor .t posiioned ajcn.a 'nut 4 f The nIut 14 may, *have bearing flange 488 adjacent the support beaing 426',an a.threaded. end .478 spaced apart from the bearing flange. A retaining m~emfber 450 haviing initernial' threads 42 li~ae~lyengages the hedd ~d48 such.tath retaininig mebr450 cotact th suportbearing 426. %As the retaining member 450 is adjustably tightened it imparts a preload force. to the support bearing 426, compressing the support bearing 426. against the bearing flange 488.

*As shown in Figure 6, the apparatus 410 does not include a housing 124 (Figure Instead, devices such as the waterjet support beam 101 (Figure 2A) may be coupled directly to the outer race 134 of the support bearing 426'. Figure 7A is a cross-sectional side view of a drive apparatus 510 having first and second nuts 514 (shown as 51 4a and 51 4b) engaged with the threaded rod Ill1.

The nuts 5 14 may be coupled with a coupling member 517 that extends axially bctween the nuts. In one embodiment, the coupling member 517 may be integrally formed with RECEIVED TIME-3. MAR. -13: 09- -PRINT TIME= 2. APR- 1: 19 Re-end3o- 3- 02 1 2 0 PM;DAV IES COLL ISON CAVE A#A- 1 th us54admyegencrally.rigid in a. torsional direction. ad Fleif and resiIiei'it.

in te-axial direction. 'Accordingly, thopli ng mebe 517 may transmit ailfre betwe Yen 'the nuts.'514 while'at least 'restricting: rota tional otin o'n u eaiet the other..

s h die parts510 further includes a housing 524, ruiularly dsposed about'thc: nuts 5,14, ad first. and sceonid support bearings 526 (shown as 526a anS26b1), each havinigan outer, race 534 adjaoent the housing 524 in ani ine ace 532 adjacent one of the nuts 514. A retaining membier 550 may be coupled to the housing 524 to apply an axial load to the support bearings 526 *and. the nuts 514. In one embodiment. the retaining member 550 may include a collar 51. having a flange 555 in contact with the second support bearing 526b. The. collar 5S51 may be, biased against the.

second. stipport bearing 526b 'by tightening screws 553 that couple, the'collar*551 -to the ::::*.housing.524.

*.As the retaining -member 550 is, biase'd axially againt the .second,-support.

5bearig 526b., the s~c'ond.'support bean ,tanmis' l 6i66e to the,.second nut.or4b ther* h ~il S1 h'eby.' tplying* loa' to" thle, balls cnaie.wtn'theeodnu 1aia lo ad-is then transmitted viteeuln crbr51tol rsnu 514aTh rsnu .514a- transmits the. axial..force* to',thea first support be ari ngS 26a, which:' is. clamp ed between the. first nut- 5 14a'and the bearing flange 588. -Accordingly, an advantage of-the 20 apparatus. 510, shown. in Figure. 7A. is :that by adjusting the -retaining member 550,'a preload may be applied to both the support bearings 526 and the nuts 514. By applying a preload to both the support bearings 526 and the nuts 514, the apparatus 510 may reduce and/or eliminate gaps between elements of the nuts and the bearings, and may improve the accuracy with which the housing 524 is positioned relative to the threaded rodIl.

Figure 73 -is a cross-sectional -side view bf -another emnbodiment of thle apparatus 5 10 wherein a first nut 614a is coupled to a second nut 614b with a coupling member 617. The coupling member 617 may include a plurality of spaced apart teeth or splines 621 projecting axially from the first nut 614a. The splines 621 may be received in corresponding slots 619 in the second nut 614b. The splines 621 transmit RECEIVED TIME...30. MAR. -PRINT TIME= 2. APR. -11: 19 Re~erd3O- 3-02;12:OOPM;DAVIES COLLISON CAVE A# A-16 O,1P[K1Kb,.M I 13A 91AkMO**7'4AWJMR radial' motion- from ~one nut- 614 to thc other and transmit axial forices'bcfwccn the nuts 614 by engaging with end surfaces 62.3 of each' slot 619. 'As shown, in Figure 728,'the nuts 6141may be, separated from each other by removing the spli ies 62,1 fromn the slots .619.. Accordingly, an advantage of. the apparatus 5 10, shown in Figure 7B is that o'ne of the..nuts 614 may, be, remoyed, and/or replaced Without removing and/or, replacingth other nut 614..

From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration,' 1'various modifications may be made without deviatig from the spirit and scope of the invention. Accordi'ngly, th&inv'ention is,not lirnited.ex-cept *as by the appended'claims.

*Throughout this 'specification, and the. claims. which follow,. unless .the; context reuiesoteris, hewod comprise, and' variations. such as "comprises" and ,c 'piig", will be..understo do iply, the nlsoo a stated:integer,.or- steppor grou ''WI n' f Ai" '15 of ~integersor steps btntteecui:o'n.o~~ n~e rse.o~go~o neeso The reference to any prior art. in this specification is not, and shoild~not 'be taken.

as, an acknowledgment or any form of suggestion that, that prior art forms part of the' common general knowledge in Australia.

TIME3QJ. MAR.=13:09 PRINT TIME.-. 2. APR. 21 1:18

Claims (27)

1. 3-02;12:00PM;DAVIES COLLISON CAVE A O nn l m l mr.' s A- 17 N AE A 12 F THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A screw drive apparatus for positioning a waterjet cutting device. comprising: a threaded rod having a longitudinal axis and at least one helical thread; a nut disposed about the threaded rod, the nut having a channel aligned wvith and radially outward from the helical thread, the nut further having a plurality of balls engaging the helical thread of the threaded rod, the nut being rotatable relative to the threaded rod; a drive shaft disposed about the threaded rod, the drive shaft having a first end and a second end, the first end being connected to the nut; i. i a housing having a passage therethrough and at least one support bearing wpositioned within the passage, the support bearing having an inner race attached to the drive S, shaft;,and :n out rrace attached.. the housing, tbhe m race beigrotaitable relaive:to the outer race drive means coupled to the nut to rotate the nit on the threaded rod and move the housing along the longitudinal axis of the threaded rod; and a retaining member removably attached to the drive shaft proximate the second end thereof, the retaining member being coupled to the support bearing and movable relative to the support bearing to apply an adjustable force on the support bearing in a direction generally parallel to the longitudinal axis. 2. The apparatus of claim 1 wherein the second end of the drive shaft has threads thereon and the retaining member includes a locknut threadedly engaging the threads of the drive shaft. 3. The apparatusof claim 1 wherein the passage has an inner surface, the drive shaft has an outer surface facing the inner surface of the passage, and the retaining member has an end surface facing the first inner surface of the passage, the apparatus further comprising: RECEIVED TIME, 30. MAR. 13:0O9 PRINT TIME_ 2. APR. 11 :18 3 0 2;12:00PM;DAVIES COLLISON CAVE A A- 18 13 a first seal disposed within the passage and scalably engaging theinncr surface of the.passage and the outer surface of the drive shaft; a second seal disposed within the passage and sealably engaging the inner surface of the passage and the outer surface of the drive shaft, the support bearing being between the first and second seals, wherein the inner surface, the outer surface, the end surface, and the seals define a reservoir for retaining a lubricant.
2. 4. The apparatus of claim 3 wherein the housing has a hole in fluid communication with the reservoir to allow lubricant to enter the reservoir. S. The apparatus of claim 3 wherein the drive shaft has a port in fluid communication with the reservoir to allow lubricant from the reservoir to engage the threaded .Od, S6. he apparatus of claim 1 further comprisi ng.t least. one spacer disposed between thetaini irienber aid th suort bea ring. S7. The apparatus of claim wherein ne surface of the support bearing. is coupled to the retaining member andan opposite surface of the support bearing engages the
3. 7. The apparatus of claim I wherein one surface of the support bearing is coupled to the retaining member and an opposite surface'of the support bearing engages the
4. 9. An apparatus for coupling attachments to a scr drive device, the screw drive device having a nut rotatably engaging a threaded rod to convert rotational motion of one of the threaded rod and the nut to 1 wheretilin one surface motion of the suppother of the threaring is coupled to the retaining member and an opposite surfaceof the support bearing engages the nut. 9. An apparatus for coupling attachments to a screw drive device, the screw drive device having a nut rotatably engaging a threaded rod to convert rotational motion of one of the threaded rod and the nut to rectilinear motion of the other of the threaded rod and the nut, the apparatus comprising: RECEIVED TIME_ 30. MAR..13:09 PRINT TIME. 2. APR. 11: 18 e n d 30- 30 2;12:OQPM;DAVI ES COLLISON CAVE A A- 19 14 a drive shaft disposed about the threaded rod" the drive shiaft 'ha'ing a first 6nd and a second cnd opposite chec first enid,: the. first cnd bcing connected t' h nta fange extenidinig'away thcrcfrorzdhaiga a housing having a passage therethroub th asagehvn is n scn -support bearings positioned therein. the first support bearin being adjacn th 'lngc. ac Support bearing having an inner race attached to the drive shaft and -an outer racc attached to the housing.. each! inner raebi~'oaa~ eaiet orspdigoucra; a retaining Memrntr remonvably -attached to the drive shaft poiaethe, second end thereof, the retininti member being coupled to the second support bearing and movable relative to the second support bearing to control a force on the first- and second support bearings in a direction generally parallt o a 1longitudinal axis-'of the. threaded -rod by, biasing the -first support member against the flangi.e and biasing thc second support member against the housing. 0 .T h e:ap paratu s of c lam 9 cwh rein th se o d e d f t e d i s a t h s thread'S tanigmemer~i~ue clcnut efraidyngagingth &threa&,st fthe' ~r d th b nc~u cs a io nr~a eaz driveshaft.
5. 11. The apparatus of claim 10 wherein the first and second 'Support bearings arc angular contact bearings.
6. 12. The apparatus of claim 9, further comprising a bearing spacer between the first and second support bearings.
7. 13. The apparatus of claim 12 whercin the bearing spacer depends from the housing.
8. 14. The apparatus of claim 9 wherein the passage has an inner surface,. the drive shaft has an outer surface facing the inner surface of the passage. and the rctaining member has an end surface facing the inner surfaice of the. passage, the apparatus further comprising: ~RECEIVED TIME-.%. AR. -PRINJT T[ME=. 2. APR. 11:18 3-02;12:OOPM;DAVIES COLLISON CAVE A- 1 5 a first seal disposed within the passage and sealably engaging- he inner surface of the passage and the outer surface of the drive shaft; and a second seal disposed within the passage and sealably engaging the inner surface of the passage and thc: outer surface of the drive shaft, the support bearing being bctween the first. and second seals, wherein the inner surface, the outer surface. the end surface, and the seals define a reservoir for retaining a lubricant. IS. An apparatus for coupling to a screw drive device, the screw drive device having a nut rotatably engaging a threaded rod to convert rotational motion of one of the threaded rod and the nut to rectilinear motion of the other of the threaded rod and the nut. the apparatus comprising: a housihg having a passage therethrough and at least one support. bearing positioned within the passage, the support bearing having an inner race connected to the: nut and an.outer race connected to the housing, the inner race being rotatable relative to the outer c e a d j: i l a nd nd. Sa retainig member removably attachable t6 the nut, the retaining meber. being coupled to the support bearing and moiablerelative to the supp rtbearinl apply an adjustable force on the support bearing in a direction generally parallel to a longiudinal axis of the threaded rod.
9. 16. The apparatus according to claim 15 wherein the nut has a threaded end and the retaining member threadedly engages the threaded end of the nut.
10. 17. The apparatus according to claim 15 wherein the support bearing is a first support bearing, the apparatus further comprising a second support bearing spaced apart from the first bearing and positioned within the passage of the housing. the. second support bearing having an inner race connected to the nut and an outer race rotatable relative to the inner race and connected to the housing.
11. 18. An apparatus for coupling to a screw drive device, the screw drive device having a nut rotatably engaging a threaded rod to convert rotational motion of one of RECEIVED TIME 30. MAR. 13:09 PRINT TIME 2. APR. 11:18 Resend3O- 3-02;12:00PM;DAVIES COLLISON CAVE p A- 21 the threaded rod and the nut to rectilincar motion of the other of the thrcadd rod and the nui, the apparatus comprising: at least one support beaing, the support bearing having an inner race and an outer race, the nut extending through the inner race and being attached to the inner race, the inner race.being rotatable relative to the outer race, and. a retaining member removably attached to the nut, the retaining mcmber being coupled to the support bearing and bing movable relative to the support baring t ly an adjustable force on the support bearing in a direction generally parallel with a longitudinal axis of the threaded rod.
12. 19. The apparatus according to. claim 18; further comprising at least one spacer positioned between the retaining member and the support bearing.
13. 20. The apparatus of claim. 19, further comprising a housing connected to the oute rac of the preari
14. 21. The apparatus of claim 19 wherein the retaining member is threadably connected to the nut, the retaining member engaging one surface of the support bearing. and S biasing an opposite surface of the support bearing against the nut.
15. 22. A screw drive apparatus for positioning a waterjet cutting device comprising: a threaded rod having a longitudinal axis and at least one helical thread; a first, and second nuts disposed about the threaded rod, each nut having a channel aligned with and radially outward from the helical thread, each nut further having a plurality of balls engaging the helical thread of the thrcaded rod..- each- nut being rotatable relative to the threaded rod; a coupler extending between and coupling the first and second nuts; a housing disposed about the first and second nuts; a first support bearing between the first nut and the housing, the first support bearing having an inner race adjacent the first nut and an outer race adjacent the housing: RECEIVED TIME,30.MAR. 13:09 PRINT TIME_ 2. APR. 11:18 3 0 2;12:00PM;DAVIES COLLISON CAVE A- 22 a second support bearing between the second nut and thc housing, the second support bearing having an inner race adjacent the second nut and an outer race.adjaccnt the .housing; arnd. a retaining member.removably attached to the housing and being coupled to the first support bearing and movable relative to the first support bearing to apply an adjustable force on the first support bearing, the coupler, and the second support bearing in a direction generally parallel to the longitudinal axis.
16. 23. The apparatus of claim 22 wherein the retaining member includes a collar adjacent the first support bearing and a threaded fastener connecting the collar to the housing.
17. 24. The apparatus of claim 22 wherein the coupler includes an axially S resilient, flexible member between the first nut and the second nut. .25 Th e ais of c aim S24 .wher in e cupl' y fo m d with the first and second iuts:.
18. 26. The apparatus of claim wherein the coupler includes a spline member S attached to the second nut configured to be received by a corresponding aperture in the first nut.
19. 27. A method for operating a screw drive apparatus having a nut rotatably :engaging a threaded rod and a support bearing having an inner race coupled to the nut and an outer race rotatable relative to the inner race, the method comprising: applying an adjustable force to at least one of the inner race and the outer race. in a direction substantially along a longitudinal axis of the threaded rod to bias at least a portion of the one race toward at least a portion of the other race; and rotating the nut relative to the threaded rod. S. RECEIVED TIME 30. MAR. 13: 09 PRINT TIME- 2. APR, 1 1 18 3-02;12:00PM;DAVUES COLLISON CAVE A A- 23 18
20. 28. .The method of claim. 27 wherein the stp of applyiig 'an adjustable force includes rotating a retaining member relative to the nut and engaging a surface of the retaining member with a surface of the support bearing.
21. 29. The method of claim 27 wherein the act of applying an adjustable force includes clamping the.support bearing between a retaining member. and a surface coupled to. the nut, the retaining memnber being movable relative to the surface of the nut. The method of claim 23 wherein the support bearing is a first support bearing, the apparatus has a second support bearing spaced apart from the first support bearing, and wherein the step of applying a force includes applying a force to a spacer between the first and second support bearings.
22. 31. A method for operating a, screw drive apparatus having a nut rotatably S ngagjn a threaded rod, d:a support bing having an nerace coupled t ie nutad a our race -rotata t-raci i di outer xe ujjo innerace, cOmprsing. *applyiig an adjustale force to one portion f at least one of e inner raceand S. the outer race in a direction substantially along a longitudinal axis of the threaded rod to bias the one portion toward an adjacent portion of the at least one of the inner race and the oute race; and rotating the nut relative to the threaded rod.
23. 32. The method of claim 31 wherein the step of applying an adjustable force includes rotating a retaining member relative to the nut and engaging a surface of the retaining member with a surface of the support bearing.
24. 33. The method of claim 31 wherein the act of applying an adjustable force includes clamping the support bearing between a retaining member and a surface coupled to the nut, the retaining member being movable relative to the surface of the nut. RECEIVED TIME.30.MAR..13:09 PRINT TIME 2. APR.11:18 3-02;12:OOPM;DAV1ES COLLISON &CAVE A# A- 24
25. 34. A method 'for operating a screw drive paau ai~f~tadscn nuts rotatably engaging a threadcd rod and* first'and -second suppr -bearings, each supor bcaring havinhg.an inner. race coupled to the respective nut and an outer race. rotatable rcatve to the iner race, the method comprising:' appljying an adjustablc force to at'IcaSt one -of the inner race and the outer-race of the first..suppo rt bearing- in a- dircction s'ubszrilyaon ogtdna xso h tihreaded rod 'to bias at -least a portion of the o6ne race toward! at least a portioni of zhe te race of the first support bearing; transmitting the adjustable force axially from the first support bearing to the first nut and franm the first. nut to thie second nut; and transmitting the adjustable' force axially from the second, nut to the second support bearing. The method of claim. 34. where'in the step otrnmiting theajsbe force ~~ofrn fro -h is uotescn u nlds*rnmtigteadjustablefrctroga feb*ew the t iecn-aid§'tas I**i sline mmibe btween the first ad sec nd nuts
26. 37. The method of claim 34 wherein the step of trn itngheajsbl force from the first support bearing includes applying a force to balls of the first and second nuts.
27. 38. The method of claim 34, further comprising removing the first and. second nuts independently from the threaded rod. DATED thiis 30T day of MARCH 2002 FLOW INTERNATIONAL CORPORATION by DAVIES COLLISON CAVE Patent Attorneys for the Applicant RECEIVED TIME..3. MAR. 1j3: 09.-M.M PRINT TIME,. 2. APR..]jV:18