US2464997A - Lubrication of rotary expansible chamber sliding vane tool motors - Google Patents

Description

' March 22, 1949. E. H. SHAFF LUBRICA'I'ION OF ROTARY EXPANSIBLE CHAMBER SLIDING VANE TOOL MOTORS 3 Sheets-Sheet 1 Filed Jan. 8, 1944 n m m fbrne s March 22, 1949.

E. H." SHAFF 2,464,997 LUBRICATION OF ROTARY EXPANSIBLE CHAMBER SLIDING VANE TOOL MOTORS Filed Jan. 8, 1944 3 Sheets-Sheet 2 jrwerzior EggzeSiHS/zfi March 22, 1949. E; H. SHAFF 2,464,997

LUBRICATION 0F ROTARY EXPANSIBLE CHAMBER SLIDING VANE TOOL-MOTORS 3 Shets-Sheet 3 Filed Jan. 8, 1944 Patented Mar. 22, 1949 UNITED STATES PATENT OFFICE LUBRICATION OF ROTARY EXPANSIBLE. CHAIVIBERI SLIDING TODL MO- TORS Ernest H.'. Shaif; Spring Lake; Michg assignorto; Keller .Tool Company, a corporation of Micki gan Application JanuaryVS'; 1944; SerialNo: 517526 The present invention pertains toimp'rove ments in portable pneumatic .tools, and 'more' par' tic'ul-arly tov such tools embodying rotary'type':

pneumatic motors;

One object of thepresent invention 'is to'pro vide a novel and: improved lubricating arrangement for the cylindertwalls' of the motor of such.

a device, which'arran'gement'is ofsuch character asto insure adequate andv effective lubrication: during operation. of the motor; without danger:

of floss of the lubricant twhenzthe'tool is :idle.

More:particul-arly;. it isc-anr object. to provide a: lubricating." arrangement for the" cylinderrwallsn ofithe motorofsuch: a .devicezintwhi'chzhigh ire-*- quency pressure impulses: in arestri'cted. passage leading. from a lubricant chamber to the .motor; cylinder are setup intermittently; during opera-F tion of the tool: and: utilized: to efiectuate' the-12 Fig. 1 is afragmentarysectional viewon line I I a of v Fig. Zlshowinga detail of construction. Fig. 2 isan explodedperspective view-of the, tool of 1.

Fig. 3 is an explodedperspective viewot thev motor assembly for the tool.

Figs. 4 and5' are enlargedtransverse sectional.

views taken substantially along the lines. 44

and 5-5, respectively, in Fig. 1.

Fig; 61s a transverse sectional "View through the motor tak'en substantially along the line. 66 in Fig." 1.

Figs. 6 and'6 "are:stop motion sectional'views similar to Fig. 63

Fig. 7 is'a fragmentary detailsectional view Whilethe'= invention is susceptible of various. modifications and alternative constructions, I have shown in the drawings and" will herein describeindet'ail the preferred embodiment, but:

it is tob'e'understoodthat'I do not thereby intend to limit the invention to the specific =form'" disclosed; but intend to cover all "modifications and" alternative" constructions falling'withirrthe spirit and scope' of theinventi'on as expressed in the appended claims.

K'1hese' blades 36* are received inslots 31 which Referring more particularly to the exemplary embodiment of the 'invention illustrated in the" drawings, the tool there shown comprises a tool spindle 10 carryinga: grinding. wheel II driven by 'a rotary type pneumatic motor designatedi Compressed: air for operating the motoris supplied throu'gh'aznipple I 3 at the generally as" I2.

rear'end of the tool; thenipple servingior at-1 tachment' of a'flexible' supply :hose I4 to any suit able source .(not shown).

To house the motor. I2 and. spindle ID, a: generally.cylindrical-zcasingr orhousing' I5 is em-. ployed. Arhandle:lfiisthreaded in one end of the: casing (see-Fig. 2). as indicated at I! andtclamps; the m0tor withinthesoasing against a'shoulder" I8 in the latter :(Figi: 1). The. opposite end: portion: I 5a1'0f the casingnl 5 is1-of :reduced: diameter;

and: constitutesia' tubular spin'dlehousing. At

opposite ends. of this: spindle-housingare ball bearings. I 9 and" for supporting the spindle l0,

thelatten'bearings also serving to support one end of the rotor'ofithe motor. The outer'race of the-ballbearing 20- is clamped-against a shoulder 2| bye-lockingring-22 threaded in the end of the casingvand having a packing-23 disposed between i A- needle bearing 24: within the housing also aids in supporting they it and the bearing: races.

spindle;-

is =eccentric with respectto the axis of the cylindrical body; The periphery of the rotoris. cylindrical. andisdimensioned for substantially a line-"contact L with the inner wall of the cylinder.

bore -or chamber (see. Fig. .6) when the rotor is disposed concentrically. with. thenbody. of the. cylinder. The endsv offthe rotor have reduced. diameter axial'projecti'ons. 28; 29 .thereom'one beingreceived within .a ballb'earing 30 and the, othernbeing. splin'ed withintheltelescoping inner end'ofithetool spindle I'O'and thus supported by v the bearing: I9; Retainer rings. 3|. and 32 hold taken substantially along the 1ine"'!-I in Fig. 6; end p a es 33 and 34 inposit na pp site s of the cylinder and "also support :.the bearings I 9'."

and 30 which in turn support the rotor'projections 28 'and 29i D'owels35'serve'to'locatethe end plates;

The motorrotor 26 -'is provided with-aplurality of blades 36 (here shown as-three innumber) equidistantly spaced aboutthe axis of the rotor and-movable radiallyof the'latter under the compul'sion of centrifiigalfbrce (see Figs. 3 and 6).

extend longitudinally of the rotor and the outer edges of the blades Wipe in sealing contact with the inner wall of the cylinder. To revolve the rotor, compressed air is admitted to the cylinder through inlet ports 38 located on one side of the line of contact L of the rotor with the cylinder and permitted to escape through exhaust ports 39 located on the opposite side of such line of contact. In the present instance the exhaust ports 39 are formed as a plurality of longitudinally spaced circumferentially elongated slots in the cylinder, and the surrounding casing I is longitudinally slotted as indicated at 40 (Fig. 2) so that the exhausting air is free to escape to atmosphere. The intake ports 38 are, on the other hand, supplied with compressed air through a pair of passages 4l drilled in the cylinder and leading from the right-hand end thereof (as viewed in Fig. Such passages communicate with a corresponding pair of supply passages 42 formed in the handle I6 and registering with holes 43 in the end plate 34 which in turn register with the ends of passages 4|.

The admission of compressed air to the supply passages 42 is controlled by a manually operable valve 44 and a governor 45 (Fig. The valve 44 comprises a bushing 46 threaded in a transverse bore 41 in the handle l6 and having a valve element 48 carried by a valve stem 49 slidable in it. A compression spring 50 interposed between the bottom of the bore and the valve element normally urges the latter into closed position against the valve seat constituted by the inner end of the bushing. A hand lever 5| pivoted on the handle l5 and overlying the end of the valve stem 49 serves to thrust the latter inward for moving the valve element away from its seat to open position. Compressed air is led through a passage 52 from the nipple l3 to the lower end of the valve bore 41 and when the valve element 48 is open, passes upward about it and around the reduced portion of the valve stem 49, finally emerging through openings 53 in the bushing 46. The compressed air leaving these openings 53 passes through a short bore 54 into a chamber 55 from which the passages 42 lead.

Entry of the compressed air into the chamber 55 is regulated by the governor 45 in order to maintain the speed of the motor substantially constant at a value determined by the setting of the governor. As shown, the governor 45 comprises a pair of flyballs 56 pivoted on a head 51 secured to the rotor extension 29 and located within a governor chamber 58 in the handle "5. These fiyballs 56 have fingers 56 bearing against the end of a stem 59 which is slidable axially in a bushing 59 threaded in the portion of the handle separating the chambers 55 and 58 and slotted to form ports 60 controlled by the stem 59. The fiyballs act in opposition to the pressure of the air acting on the end of the valve stem exposed in the chamber 55, and tend to close the ports as the speed increases to throttle the flow of air from the bore 54 into the chamber 55 variably, depending upon the axial displacement of the stem.

Provision is made for lubricating the spindle bearings I9, 20 with lubricant, such as light grease, from a reserve supply formed by the governor chamber 58. For that purpose an axial passage 6| is provided in the rotor 26 extending from end to end therethrough and communicating at its right-hand end with the interior of the governor chamber 58. The latter is retained under substantial pressure by compressed air leaking along the stem 59 so that lubricant is forced from the governor chamber 53 through the passage 6| to the outer end of the latter in the rotor projection 28, the spindle housing being vented to facilitate such flow as hereinafter described. The spline coupling between the tool spindle I0 and rotor projection 28 is such as to permit lubricant to emerge from the latter into the spindle housing l5 through which it passes to the several bearings I9, 20 and 24. For that purpose, the rear end of the spindle is made in the form of a sleeve having a plurality (herein four) of longitudinal slots 62 (Fig. 5) which are of somewhat greater length than complemental spline teeth 63 on the rotor projection 28 (Figs. 1 and 5). Since the slots thus extend somewhat beyond the end of the rotor projection, lubricant is free to flow from the open end of the passage 6| out through the unobstructed portions of these slots 32 into the spindle housing 15. The ball bearing 35 at the other or righthand end of the rotor 26 (Fig. 1) is lubricated directly from the governor chamber 58, being mounted in one wall of the latter.

Venting of the spindle housing I5 is accomplished through a passage 14 drilled in the cylinder 25 (Figs. 1 and 7) leading to a lubricant port 15 which opens into the exhaust zone or portion of the cylinder alongside the exhaust ports 39. Tubes l4 pressed in the passage 14 bridge the exhaust ports or slots. At its end adjacent the spindle the passage 14 registers with a hole I6 in the end member 33, the latter having a radially extending relief or slot in its face adjacent the bearing l9. Since the spindle housing is thus vented through bearing l9, lubricant is carried to it and on to the port 15 where the rotor blades pick it up to wipe it around the cylinder walls.

Lubrication of the cylinder wall to prevent scoring by the rotor blades is an especially acute problem in tools of the general type described and, in accordance with one aspect of the present invention, a novel arrangement is provided for furnishing lubricant for that purpose and may serve either as a supplement to or instead of the supply to the cylinder so far described. A reserve supply of lubricating oil for lubrication of the cylinder wall is contained in a chamber 76 within the handle 16 (Fig. 1) and having a filler opening closed by a plug 16*. In brief, lubricant from this chamber 16 is conveyed to the cylinder by utilizing the motor rotor, when the latter is in operation, to apply intermittent high frequency impulses of pressur to an extremely restricted passage leading from the supply chamber to the cylinder.

In the particular construction illustrated (see Figs. 1, 4 and 6), lubricant is supplied from the chamber 16 through a small passage 11 in the handle l6 and then through a corresponding small passage 18 in the cylinder 25 which terminates in a lubricant port 19. This latter port 19 is located substantially midway between the line of contact L between the rotor and cylinder and the adjacent end of the exhaust slots 39. As the rotor 26 revolves, each successive blade 36 passes from the position of Fig. 6 to that of Fig. 6 and at which latter position communication between the lubricant port 19 and exhaust slots 39 is cut off. Thereafter the blade and rotor compress the air trapped between the blade and the lubricant port, applying pressure to the latter. When the blade passes the lubricant port ,(Fig. 6 the "rotor. The rotor of the particular toolillustated revolves at nearly 20,000 P. M. when running free and has a normal operating speed of about 12,000 R. P. M. when controlled by the governor 45 for normal operation. In other words, there are normally 36,000 pressure impulses per minute or 600 per second applied intermittently to the lubricant port i9.

To afford a suitably high degree of restriction in the passage '17, '18 between the lubricant reservoir 76 and port 79, the passage is slightly enlarged at ll (Fig. 1 and a pin Tl of only slightly smaller diameter inserted in this enlargement. By way of example, the enlarged portion of the passage may be 0.0960 inch in diameter and the pin 0.0937 inch in diameter. As shown, such enlarged portion is located at the junction of the handle with the cylinder.

It has been found that when high frequency pressure impulses are applied to such a restricted passage in the manner described, that an efiectual and continuous flow of lubricant takes place from the supply chamber to the lubricant port. At the latter it is picked up by the blades and wiped around the cylinder walls. On the other hand, when the tool is idle, the passage from the supply chamber is so highly restricted at Ti 11 that no appreciable amount of the lubricant leaks into the cylinder. Theoretical analysis of the action of the device in inducing such flow of lubricant is difiicult. Apparently, however, the successive sudden releases of pressure at the lubricant port cause corresponding minute increments of lubricant to be aspirated through it, and the next succeeding blade each time intercepts the increment of lubricant before it can be blown out of the exhaust slot and wipes it around the cylinder wall.

The intermittent pressure applied by the motor to the lubricant chamber it may also be utilized to inject lubricant into the motor cylinder through the port '15. For this purpose, the passage 14 (Fig. 7) is extended rearwardly from the port 15 as at M for connection with a passage 80 in the handle, leading to the chamber 16.

As previously noted, the lubricant port i opens into the inner cylinder wall on the exhaust side. When so arranged, the pulsations of pressure applied to the port is are transmitted through the passage l8, 71 to the lubricant in the supply chamber 16, thus forcing such lubricant out through the passage 80 to the other lubricant port where it is picked up by successive ones of the blades 36 and wiped about the cylinder wall. The passage 80, like the passage 18, 11, must be highly restricted in order to prevent using an excess of lubricant.

I claim as my invention:

1. In a portable tool, the combination of a rotary pneumatic motor including a cylinder having a rotor eccentrically mounted therein, said rotor having a plurality of blades thereon and movable outwardly therefrom by centrifugal action in the rotation of the rotor, said cylinder having air inlet and exhaust ports disposed on opposite sides of the point of least displacement of the rotor from the cylinder, said cylinder also having a lubricant port disposed between said point and said exhaust port and at a lesser distance from the latter than the spacing between.

successive blades, and means defining an air tight lubricant chamber communicating withsaid lubricant port through a highly restricted passage, each of said blades being operative in the rotation of the rotor to trap and deliver to said chamber through said lubricant port a small quantity of air serving to force the lubricant in the chamber reversely through the port following movement of the blade past the port.

2. In a port-able tool, the combination of a r0- tary pneumatic motor including a cylinder and having a cylindrical rotor eccentrically mounted therein and disposed in line contact with the.

inner wall of the cylinder, said cylinder having air inlet and exhaust ports disposed on opposite sides of the line of contact between said rotor and cylinder, said rotor having a plurality of blades thereon movable generally radially of the same, said cylinder also having a lubricant port therein disposed between said exhaust port and the line of contact between the rotor and cylin 0 therein and disposed in line contact with the inner wall of the cylinder, said cylinder having air inlet and exhaust ports disposed on opposite sides of the line of contact between said rotor and cylinder, said rotor having a plurality of blades thereon movable generally radially of the same, said cylinder also having first and second lubricant ports therein, said first lubricant port being disposed between said exhaust port and the line of contact between the rotor and cylinder, and means defining a closed lubricant chamber communicating with said first lubricant port and also defining a second passage from said chamber to said second lubricant port, the latter port being located Within said cylinder in a zone constantly in communication with said exhaust port.

4. A portable tool having a rotary pneumatic motor including a cylinder and a rotor, said rotor having an axial projection at one end thereof provided with longitudinally extending spline teeth, a tool spindle telescoped over said projection and having longitudinally extending slots therein receiving said teeth, said teeth being disposed to stop short of the inner ends of said slots to leave the inner portions of the latter open, a bearing supporting said spindle, and said rotor having an axially extending passage therein for supplying lubricant to said bearing, said passage terminating at the end of said projection, whereby lubricant emerging from the passage at the end of said projection is free to pass outward through said open inner portions of said slots into proximity with said bearing.

5. A portable tool having a rotary pneumatic motor including a cylinder and a rotor, an elongated body providing a motor casing with extensions at opposite ends of the motor defining, respectively, a lubricant chamber and a spindle housing, said rotor having an axial projection on the end thereof adjacent said spindle housing, a tool spindle in said spindle housing telescoped over said projection and splined thereto, such spline connection including longitudinal slots in said spindle receiving teeth on said projection, bearings at opposite ends of said spindle housing supporting said spindle, the bearing at the inner end of said spindle housing receiving the end portion of the spindle telescoped over said projection and thereby also supporting the adjacent end of said rotor, said rotor having an axial passage therethrough leading from said lubricant chamher and terminating at a port in said projection, said teeth extending for only part of the length of said slots to permit the egress of lubricant from said port into the spindle housing at a point intermediate said bearings, and means for admitting air under pressure to said lubricant chamber to force lubricant from the latter through said passage and out of said port.

6. A portable tool having a rotary pneumatic motor including a rotor, said rotor having an axial projection at one end thereof, a tool spindle splined to said projection, bearings for said spindle and said one end of the rotor, means defining a lubricant chamber adjacent the other end of said rotor, and said rotor having an axial passage therein leading from said chamber and through said projection to a point adjacent said bearings, said splined connection including islot permitting the escape of lubricant from saidpassage.

ERNEST H. SHAFF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 316,309 Telfer Apr. 21, 1885 560,314 Fertig May 19, 1896 611,700 Miner Oct. 4, 1898 927,929 Bearinger et al July 13, 1909 1,122,109 Hansen Dec. 22, 1914 1,385,880 Master July 26, 1921 1,514,007 Moore et al Nov. 4, 1924 1,931,167 Price et al. Oct. 17, 1933 1,933,000 Young Oct. 31, 1933 2,099,280 Shafl Nov. 16, 1937 2,246,910 Amstberg June 24, 1941 FOREIGNPATENTS Number Country Date 9,645 Great Britain Apr. 25, 1902

Images