US2373669A - Fluid power motor - Google Patents

Description

April 17, 1945. J. STURROCK FLUID POWER MOTOR Filed March 18, 1942 3 Sheets-Sheet 1 April 17, 1945 I FLUID POWER MOTOR Filed March 18, 1942 INV EN TOR.

J. STURROCK 2,373,669

3 Sheets-Sheet 2 Patented Apr. 17, i945 FLUID rowan MOTOR James Sturrock, Cleveland Heights, Ohio, assign of Ohio or to The Rotor Tool Company, a corporation Application March 18, 1942, Serial No. 535,884

Claims.

This invention relates to improvements in rotary fluid motors. Some similar embodiments are shown in my co-pending patent application Serial No. 435,883 of identical filing date, but nowabandoned. This. present application refers more to the reversing valve and mechanism and the air passages to and from the valve and through the motor, the handles and attendant parts.

My invention will be herein described as pertaining to rotary pneumatic tools but it should be understood that any reference to compressed air as a motive media includes any other form of with a uni-directional tool of similar displacement and identical rotors.

Accordingly, I have had as objects of my invention:

(1) To produce a reversible tool having the. same power as a uni-directional tool of the same 4 displacement. V

(2) To produce a tool having greater efliciency and the same power whenoperated' in either direction and simpler means to determine or change the direction of rotation.

. fluid power applicable to my invention when broadly interpreted.

There are two general types of pneumatic rotary motors used to power portable tools on the market today. One has a concentric rotor with a plurality of vane slots cut in it, mounted eccentrically in a cylindrical bore, with vanes reciprocating in theslots to maintain contact with the cylinder walls under centrifugal or other forces.

been marketed and developed practically exclusively by the assignee of this application under their issued patents. This type consists of an eccentric rotor mounted on a shaft which is concentric with a bored cylinder and an abutment mounted for reciprocating motion in a slot in the part containing the bored cylinder. to contact with the eccentric rotor. Usually, though not necessari1 y. there is an inlet and exhaust port entering the bored cylinder one on either side of the abutment slot adjacent thereto.

I will illustrate my invention with an embodiment of the abutment type but it is not limited to that type but many of its features are applicable to all types of fluid motors. J

Throughout the many years, during which pneumatic tools have been designed and marketed, manufacturers have been conscious of a limitation which they have not been able to rectify, i. e., that a directionally reversible tool has not had as much poweras if parts of the same size and displacement had been used in a uni-directional tool. Frequently the power of a reversible tool is much less in one direction than in the other and the tool is designed to fav :r the direction most used. This is especially customary and noticeable with internal vane tools.

50% loss of'power is not unusual in the reverse direction under these conditions.

30% loss of power is not unusual when the power is the same in both directions as compared (3) To produce a more powerful and efiicient reversible tool in proportion to its weight.

(4) To produce a simpler speed direction control.

(5) To control the direction of rotation by manual selection of the exhaust ports only, as com- This type I will call the vane-type. The other type I will call the abutment-type. It has pared with a method that manually switches both i the inlet and exhaust ports.

(6) To switchby a fluid operated means the inlet port at a point remote from the manual selector of the exhaust port.

(7) To improve the efliciency of the tool by materially shortening and straightening the air passages.

(8) To muflle the tool.

Further objects and novel features will be noted, and apparent from the drawings, claims and specifications which follow wherein identically or similarly numbered parts are identical or substantially equivalent and Fig. l is a longitudinal view in elevation of an embodiment of my invention, partially broken.

away.

Fig. 2 is a sectional view out substantially on line 2-2 of Fig. 1. Fig. 3 is a sectional view out substantially on line 3-3 of Figs. 1 and 2.

Fig. 4 is a sectional view out substantially on line 4-4 of Fig. 2.

Fig. 5 is a sectional view out substantially on line 5-5 of Figs. 1 and}.

Fig. 6 is a sectional view similar to Fig. 3v showing a modified form of my invention.

Fig. 7 is a sectional view of cut substantially on line 1-1 of Fig. 6.

Fig. 8 is a sectional view out substantially on line 8 8 of Fig. 6. Fig; 9 is a sectional view of modified part;

Although the embodiment of my invention shown in Fig. 1 and Fig. 2 illustrates a pneumatic 4 rotary tool suitable'for drills, reamers, taps, nut setters, many features of my invention are applicable to other uses and types of tools. Gen-.

e1 ally speaking, this embodiment is composed of a v l selector control valve l5.

called by me a duplex valve, and hereinafter described, three similar motor cell units ll, l2 and I3, a speed reducing unit H, and an exhaust Fig. 3 shows in section a cylinder casting l6 having a bore Concentric with the bow is a shaft I8 upon which is keyed an eccentric rotor "I, the rotor being free for limited sliding movement on the shaft. Air may enter through a longitudinal passage or port 22 and into b'ore through passage 23 and may leave the bore I! through passage 24 and longitudinal passage or port 25 or vice versa according to the positioning of a control valve l hereafter described in detail. The switching of the inlet and exhaust ports iseffective to reverse the direction of rota tion of the rotor. Special notice should be taken of the symmetry of the optional air passages used either for exhaust or intake according to the rotational direction desired described here and hereafter.

A vertical slot 30 is cut through a casting I6,

with a milling cutter, intermediately ports 22 and 25 (see Fig. .3).

An abutment 3| is mounted .in slot 3|! for reciprocating motion to'maintain contact between one end of abutment. 3| and the peripheral surface of the eccentric rotor I9 and to maintain separation between the chambers 32 and 33, one of which is a pressure chamber and the other an exhaust chamber.

As shown in Fig. 2 on each side ofeach cylinder casting I6 is a separator plate 34, forming a.

thrust bearing plate to take the end thrust of the rotors I9, which bears chiefly to the left as shown in Fig. 2, mainly because of air pressures.

, These plates are perforatedto pass the shaft l8 and to continue longitudinally ports 22 and 25. The separator plates 34 divide the. bores H, which would otherwise be joined, into separate 7 motor cell units, such as H, I 2 and I3.

Ball bearings 35 and 36 for shaft l8 are mounted in end plates 31 and 38 respectively,

spade casting handle assembly "I, with suitable 'air passages, and a remotely controlled valve versible.

parallel alignment. All cylinder castings, rotors, abutments, separator plates being identical and symmetrical, thus are interchangeable and re- Their identity facilitates standardization ,both for the manufacturer and the customers parts and repair department. The slot 30 is an easy milling operation. Parts may wear more on one surface than the other because of the air inlet being to one end and on one side of the tool so that reversing such parts as the separator plates :as well as interchanging them gives two wearing surfaces and accordingly prolongs their-useful life. v

*If the tool is used principally in one direction, and only occasionally in reverse, the tool may be reassembled with all parts reversed so that the worn surfaces such as in the slot 30 will be reversed, saving the necessity of replacing the parts thereby securing dual life. This reversing can take place without decreasing the power of the tool because of the symmetry of the air passages and the parts In the manufacture of such tools one handicap is the necessity of keeping a wide variety of tools in production even though the volume in some instances is not high. This construction has the great advantage of flexibility of production. Tools of various horsepowers may be made from practically identical parts byincreasing the length of the individual units, which change need not involve extensive change in dies or fixtures and an individual. production run may be increased by machining a variety of motor cell parts of various lengths at the same time without changing the machine setup materially. Also identical parts are usable for either or both dialthough it is in the scope of this invention to mount shaft hearings in any suitable position and/or the making of one or more separator plates integral with bearing mounting plates.

The cylinder castings l6 and the contacting surfaces of the separator plates 34 and the end plates 31 and 38 are surface ground; and the cylinder casting IS, the rotor l9 and the vane 3| are of such close longitudinal lengths that a running fit is effected with the separate plates while maintaininga substantial air seal therebetween.

.Since such an air motor is not self-starting except when the inlet passage 23' or 24 is between the near contacting surface of the rotor I9 called the'land 40 and the abutment 3|, the motor units are not usually used singly although such a construction is included in the scope of rections of rotation.

The slot 30 is covered by a cap 43 which embraces the length of the motor cell units such as.

H, l2 and I3 and not only aids to align them but also to space'the width of slot 30 supporting it from collapse by external forces.

Cap 43 can be made without a reversing valve as shown by 43" in Fig. 9 with an exhaust port 11' continued through .or adjacent to the cap. Then further standardization of parts may be accomplished because by reversing this cap on the cylinder casing I6 Fig. 3 the direction of rotation will be reversed so that practically the same parts may be used for reversible tools and uni-directional tools having either left or right.

hand rotation particularly because the power of the tool is the same in either or both directions in contra-distinction to all tools now on the market.

Spade handle units Fig. 2 shows the threaded opening 45 through which the live air enters.- Chamber 46 is an oil reservoir fillable through plug 41. Hollow plug 48 having an orifice 49 and felt-wick 50 held .in

place by a 'pin 5| is screwed into the oil cham-,

ber 46.- Changes in air pressure cause the oil to seepthrough felt 50 to lubricate air passing through opening 45.- Ball valve 52 normally held closed by a compression spring 53 is opened by a. plunger rod 54 which is actuated by a bell crank 55 which is positioned t be gripped simultaneously with the spade handle grip 56. The live air under pressure is carried through passages 51 to a groove 44 in cap 43 to press vanes 36 against their respective rotors Hi. The main flow of the live air is, however, through the bushing 58 to the governor chamber .59. A governor fill of a well-known type in the industry is mounted in the end of shaft l6 and includes a perfoby making 10 a practically continuous slot over all rated tube which has a snug running fit in bushing 58 and a sleeve 02 which opens-and closes the perforations of tube SI responsive to cenvtrifugal forces acting on weights 80. The sleeve v 62 is normally held in a position which leaves the perforations intube IiI unobstructed by an adjustable compression spring, notshown, positioned axially in the governor.

From the governor chamber 59 the air passes directly through passageway 64 to and through either (but not both) ports 61 and 68 which lead to ports 22 or 25 respectively (see Fig. 4).

A remotely controlled duplex valve 55 (see Figs. 4 and 5) is pivotly mounted on pin 85 and is selectively operable to close or to open, as the case may be, either oneof the two ports 61 or 80. This valve, its .design, use and functional location is an important part of my invention without which many of my'novel results would be unattainable. It controls the selection of which port the air may enter (22 or 25) responsive to the air 'or fluid power currents passing through either ports 61 or 68 as selected by manual means to select the exhaust port ashereafter described.

Since the air in the passage 64 is always under greater pressure than in the exhaust port (either 22 or 25 as elected) the surge of air to the unrestricted exhaust port moves duplex valve 65 to open the other port (either 25 or 22 as elected) which saidother open port becomes the inlet port to themotor, thereby making valve 65 responsive solely to the election of the exhaust port by the port to the manual exhaust selector control I5,

Exhaust selector control In the abutment slot cap 43 previously described in part b a tubular member I0 closed at three cells and so narrow that the pulsations of air. from each cylinder will tend to equalize in the chamber formed by the longitudinal ports 22 or v2! and will exhaust into tubular member I0 in paths of varying lengths, thereby eliminating much of the pulsation of the exhaust air before it emerges from the open end '80, thereby mufliing' the exhaust. I further muffle the exhaust by threadably tapping the interior bore of tube I0 to deflect the air blown from the long narrow slot I8 at right angles to the tapped or threaded surface of 10. This materially will muille the tool by toning down the screech so common and objectionable inpneumatic .tools. Thus 'I have by novel design combined a simple reversing valve with a muflierwithout addin any parts which would not be essential to the valve itself. 1

Speed reducing unit Shaft II passes through ball bearing 3B mounted in end plate 3B and terminates in an I integral overhanging pinion 85 which meshes with a gear 06 mounted on a work spindle 81. Ball bearing 04 and bearing 89 journal the work spindle in a gear box housing conventionally lubricated. The amount of speed reduction depends on the requirements of the work but since a pneumatic motor of this type must run much faster than the work spindle for many types of side handle tool. This shows a tool composed of one end, journ'aled in a bore II and held therein I for limited turning movement by a set screw I2 which operates in a radial slot I3 with enlarged ends I4. Compression spring 15 tends to press screw "into enlarged slot ends I4 to hold it in either one of its extreme positions. Air passage-- ways I6, and 11 run from ports 22 and 25 respectively to bore 1 I. Slots or slot s in tube it allow exhaust air to pass from either passageway I6 or 11 but not both. Manual lever 19 is attached 'to the closed end of tubular member 10 and cap 43 is marked adjacent to the slot I3 to indicate forward or reverse (see Fig. 1) or left or right rotation. When passageways I6 and port 22 are open for exhaust purposes, the duplex valv 65 responsively to the fluid flow closes port 22 and opens port 25 for inlet purposes, and when passageways TI and port 25 are opened for exhaust purposes the valve 65 automatically seals port 25 and opens port 22 for inlet purposes. The air exhausts from tube I0 through its openend 80. The rotation of rotor I9 is always in a direction passing first the exhaust'port, the abutment 3I- hand or other suitable indication of direction of two motor cell units II and I2 identical to those originally described except for the addition of a dead side handle and Moss IM and including a shaft I0 with a pinion 85 which may be meshed' with any suitable gears in any suitable gear box such as speed reducing unit I4 previously described.

In place of the abutment slot cap 43 there is substituted a larger casting III: which covers the abutment slots 80 and contains a recessed groove 44. Into a tapered hole I03 in casting I02 is a live handle tube I04 with a flange I05 which is held longitudinally by a nut I06 and rotationally by a dog point screw I01 in a keyway I08.

Screwed into the extended end of the live handle tube I04 is' a threaded socket I09 which holds longitudinallya control tube 0'. A double V-shapel cam II2-is attached to the control tube a ball N5 of a ball valve, opening said valve by compressing spring I I0 which normally keeps the valve closed. The double V-shaped cam is arranged for slight lost motion in the position shown and curved at either end of its .movement to hold the ball valve open in either position without eflort.

with theball valve I II open air enters through I the axial bore II'I passing by the ball,II5 and through a transverse hole H0 in an intermediate the air it'must first pass through the piece II9 pressed into tube I 04, which is round and tubular on both ends but flattened on opposjite sides through its intermediate body allowing the air to bypass the mechanism operating the ball valve on each'side thereof through two like passageways I indicated by broken lines and extending within tube I04 from the transverseand structural limitations do not permit them to be of suflicient size to efllcien'tly pass the air flow hole II8 to hole I22 where the air re-enters the through .passage I28.

.Passage I takes live air pressure from passage I2'I to groove 44 to keep the vanes in contact with. the rotor. periphery. Air pres'sure'is also communicated from groove 44 to the back of valve I26 by passage I3I (Fig. 7), to balance the air pressure on valve I26 to make it easier to turn.

The air then passes through the governor 60 past the duplex reversing valve 65 into either ports 22 and 2.3 or 24 and 25into the rotor chamber and out through either ports 24 and 25 or 22 and 23, identically as previously described relative to the first described embodiment.

Exhaust air leaves either passage 22 by pas-- sages I33 and I34 or passage 25 by passages I35 and I36 (see Figs. 7 and 8);

Cut into the left hand nd of valve I25 is a port I40 to exhaust either passage I34 or I36, into the atmosphere through passage MI in the live handle tube I04 and passage I42 in the vane cap casting I02. f

In the position of the parts shown in Figs. 6 and 8 air could pass between'passages I34 and I36 7 through port I40 but at this time the inlet ball valve I I5 is closed and by the time the control tube I I0 is revolved sufliciently to take up the lost motion in the cam II2 and to push back the ball II5 either valve I36 or I34 is completely closed for exhaust purposes.

The operation ofthis modified tool is so similar to the first embodiment that a detailed description is considered unnecessary.

One important virtue .of my invention shown in the side handle embodiment is the shortening and straightening of the air passages and as a result considerable increase in power and emciency as compared to present side handle tools.

Side handle tools now on the market take the air through the live or control handle to the governor chamber and then back to the side control handle then by double optional passageways to freely. V

The comparative simplicity of the air passages in both the embodiments described materially increases the efllciency and power of the tool as compared to tools of like weight and displacement now accepted as standard on the market.

Having described but three embodiments of my invention it is obvious that many other modifications are practical without departing from the spirit of my-invention accordingly.

I claim:

.1. In a rotary reversible motor powered by compressed air and having in combination a shaft, a motor cylinder block, walls in said block defining three openings parallel tosaid shaft, the shaft being mounted for rotation in one of said openings, the two other parallel openings having ports connecting them to the said one opening, a manually operated valve, means to normally hold said valve in either of two optional positions to optionally close one of said two openings to .atmsphere, and air operated. valve means acting sequentially to the operation of the manual valveto open the same passage to compressed air thereby electing the direction of rotation of said reversible motor. I

2. In a rotary reversible motor powered by compressed air and composed of a plurality of oppositelyindexed abutment't'ype motor cells having walls defining a bore, the combination of two parallel passages through said motor-interconnecting said cells, each passage having 'an opening into the walled bore of each motor cell;a manually operated sleeve valve to optionally close one of said passages to atmosphere, and air operated means acting sequentially to the operation of the manually operated sleeve valve'to openthe same 40 passage to compressed air to elect the direction of rotation of said reversible motor.

3. In a rotary reversible motor powered by compressed air, the combination of a shaft, 2.

' plurality of cylinder blocks each having walls F defining three openings parallel to said shaft,

the shaft being disposed for optional rotation in one of said openings, the two other parallel openings being continuous through said plurality of 'blocks and having ports connecting them to the said one opening, a groove severing one wall of 7 said block .and opening into-the said one opening and positioned between said ports, an abutment mounted for reciprocating movement in said.

groove, a plate to cover the grooves in all 'of said cylinder blocks, passages from the said two other openings into said plate, a manual valve operaibly mounted in said plate to optionally close the motor chamber and theniby double optional passages back to the control handle and then to the exhaust. -This is because in order to govern governor and then return to the control handle to select which side of the motor should become the inlet, then the exhaust must likewise bereturned to the control so one port can be closed.

In practice this multiplicity of passageway with their attendant turns, etc., must either be laboriously drilled at odd angles, with intercepting holes or cast. In the latter case the cast holes are suificiently rough to materially impede the air flow. Usually with so many passages, space all passages with openings on one side of said reciprocating abutments to atmosphere, and an air operated valve acting sequentially'to the operation of the manually operated valve to open the same passages to compressed air to effect the rotation of the shaft in an optionally selected direction.

4. In a rotary reversible motor driven b motive fluid, the combination of a motor housing having a bore and a rotor mounted in said bore, said housing having a first fluid passage with. a fluid entrance end and a fluid exit end and having a second fluid passage with a fluid entrance end and a fluid exit end, a first port interconnecting the bore with the first passage intermediate the entrance and exit ends thereof, a second port interconnecting the bore with the second passage intermediate the entrance and exit ends thereof, said'por'ts'directing -fluid to and from the here to operate the rotor, manually operated valve means arranged to be selectively actuated to either one of two positions, and fluid operated valve means acting sequentially to the operation of the manually operated valve means and arranged to be actuated by the motive fluid to either one of two positions, said manually operated valve means in one of said positions opening theexit end of the first passage to atmosphere and closing the exit end of the second passage and said fluid operated valve means sequentially closing the entrance end of theflrst tive fluid, the combination of a motor housing having a bore end a rotor mounted in said bore, said housing having a flrst fluid. passage with a fluid entrance end and a fluid exit end and having a second fluid passage with a fluid'entrance end and a fluid exit end,

necting the bore with the flrst assage intermediate the entrance and exit ends thereof, a second port interconnecting the bore with the second passage intermediate the entrance and exit.

ends thereof, said ports directing fluid to and from the'bore to operate the rotor, an abutment vane slida'bly mounted in the said housing and v engaging to rotor between said'flrst and said second ports, manually operated valve means arranged to be selectively actuated to either one of two positions. and fluid operated valve means acting sequentially to the. operation of the man V ually operated valve means and arranged to be a flrst port intercom.

' actuated by-the motive fluid to either one of two positions, said manually operated valve means in one of said positions opening the exit end first passage to atmosphere and closing the exit end '-of the second passage and said fluid operated valve means sequentially closing the entrance end of the first passage and opening the entrance end of the second passage to motive fluid, and said manually operated valvemeans in the other position closing the exit end of the flrst'passage and opening the exit end of the sec-' 7 ond passage to atmosphere and said fluid actuated valve sequentially closing the entrance end of'the second passage and opening the entrance 7 end of the first passage to motive fluid.

of the,

Images