US3048150A - Pneumatically operated tool - Google Patents

Description

1952. c. H. YOUNG 3,048,150

PNEUMATICALLY OPERATED TOOL Filed Sept. 23, 1960 2 Sheets-Sheet l IN V EN TOR. 0/4/94 5 H. YOUNG A r TOR/V5) 1962 c. H. YOUNG 3,048,150

PNEUMATICALLY OPERATED TOOL Filed Sept. 23, 1960 2 Sheets-Sheet 2 IN VEN TOR. CHARLES/I ou/v6 A TTOPNEY @ili ce 3,048,150 Patented Aug. 7, 1962 3,043,150 PNEUMATICALLY OPERATED TOOL Charles H. Young, Cleveland, Ohio, assignor to Herschel Products, Inc., Cleveland, Ohio, a corporation of Ohio Filed Sept. 23, 1960, Ser. No. 57,982 11 Claims. (Cl. 121-33) This invention relates to portable pneumatically operated power tools and more particularly to the type which may be grasped and controlled by the operator in use, such as grinders, sanders, etc. employed in light and medium duty Work.

'It is one of the objects of this invention to provide an effective and positive governor unit for insuring safe and accurate tool speed control.

Another object of the invention is a fluid motor substantially free of vibration in operation mounted in a one-piece high strength light metal housing to provide comfortable handling of the tool and safety to the operator.

A further object of this invention is a tool of this character having provisions for automatic lubrication from a relatively large oil reservoir in one of the tool handles.

Still another object of this invention is a fluid motor unit which is completely and easily removable from the tool housing without the necessity of first removing a housing cap and attendant bolts or screws.

Another object of the invention is to enable the operator to adjust and reset the motor idling speed without the necessity for taking the tool apart or to remove the governor unit from the housing.

A further object is a simplified overall construction which is easy to assemble and disassemble and which adapts the tool for working in limited or close quarters.

A further object of the invention is to reduce maintenance costs and idle time for replacements or adjustments and thereby to enable the operator to increase production at a lower cost.

A still further object is to prevent waste of compressed air or other fluid in the operation of the tool by means of a compact leakproof and simplified construction.

Another object is to insure free valve action by providing a positive plunger type throttle control for actuating the throttle valve.

Other objects and advantages of this invention will become more apparent as the following description of an embodiment thereof progresses, reference being made to the accompanying drawing in which like reference characters are employed to desginate like parts throughout the same.

In the drawings:

FIGURE 1 is a top plan view of a tool embodying my invention, one of the handles of which is shown in section;

FIGURE 2 is an enlarged section taken on line 2-2 of FIGURE 1;

FIGURE 3 is a view taken in the direction of line 3--3 of FIGURE 2;

FIGURE 4 is a transverse section taken on the line 44 of FIGURE 2;

FIGURE 5 is a transverse view taken on the line 5-5 of FIGURE 2;

FIGURE 6 is a front elevation of the fluid motor, tool spindle and associated governor unit.

In carrying out myinvention as illustrated in the embodiment shown in the drawings, a motor housing generally indicated at 1 is an integral structure of cylindrical form closed at its top, as at 2, and having an open bottom end through which the motor and governor assembly is installed or removed.

A pair of hollow handles 3 and 4 are secured to the body and extend radially outwardly thereof, the main handle 3 having a threaded inlet bushing 5 located in its free end for connection with a live compressed air line and houses the throttle valve assembly, while the hollow handle 4 serves as a lubricant reservoir for feeding lubricant to the interior of the housing.

The throttle valve assembly includes a valve head 6 normally seated on a valve seat 7 and urged to seating position by a coil compression spring 8 having its ends respectively in engagement with the valve head 6 and the spring cap 9. A loop 10 carried by the valve housing 11 engages the cap 9 to normally place the spring under compression.

Valve body 11 is press fitted with nipple 17 and has a forward portion containing bores 12 which communicate with the opening 13 in the valve seat and with the space 14 and duct 15 leading into the upper part or governor section of the housing 1. The body 11 has an annular flange 16 which rests against the free end of the threaded nipple 17, as shown in FIGURE 2.

Valve head 6 is provided with a plunger stem or pin 18 which extends and operates through the opening 19 in the throttle valve bushing 20, the forward end of the stem at 21 extending into the bushing 22 to normally engage the reduced portion 23 of the valve control plunger 24, when the valve 6 is seated in the seat 7.

The valve control plunger 24 has an enlarged portion 25 on each side of the reduced portion and these portions 25 have a snug axial sliding fit within the bushing 22 for guiding the plunger, there being a head or finger grip 26 at one terminal end of the plunger by which the plunger may be moved axially in the bushing to actuate the stem 18 and consequently seat or unseat the valve 6. The end of the stem 18 is rounded to ride along the inclined surface 27 when the plunger is operated in either direction. A spring urged ball and detent at 28 and 29, respectively, serve to properly locate and limit the plunger movement.

The bore of the housing 1 is provided with a liner 30 which has a bore Whose axis is eccentric to that of the bore of the housing 1 as clearly shown in FIGURES 4 and 5. The motor rotor 31 is thus eccentrieally mounted to rotate within the line and at one point is only a few thousandths of an inch clearance of touching the liner bore as at 32 while the space at all other points between the rotor and liner progressively increase to a maximum and thence to a minimum as the rotor makes each revolution from the point 32.

The rotor is preferably integral with the output shaft 33. This shaft extends upwardly from the rotor as at 34 through a top end plate 35 and bearing 36 and downwardly through a bottom end plate 37, hearing 38, bearing lock nut 39 and the wheel collar 40.

The rotor is provided with a plurality of bores or ducts 41 extending through the top and bottom thereof spaced apart circumferentially in the rotor and communicating with openings or ducts in the top and bottom end plates 35 and 37, respectively, as will presently appear.

The rotor is also slotted radially inwardly from its outer surface as at 42 to receive and to provide guides for the rotor blades 43. These slots also extend from the top to the bottom of the rotor and also communicate with openings or ducts in the top and bottom plates 35 and 37, respectively, as will also appear later on. The arrangement of the longitudinal slots 42 with respect to the ducts 41 is such that the slots and ducts alternate with each other around the rotor body but do not communicate directly one with another.

The rotor is also provided with slots 44 arranged respectively between the slots 42 but which do not extend to the top and bottom end plates, being limited'in extent for a distance intermediate the top and bottom end plates of the rotor. These slots 44 each communicate with the respective ducts 41.

The rotor liner is provided with a plurality of exhaust slots arranged to extend circumferentially of the liner and spaced from one another in a direction which is axial to the liner 30 itself. It will be noted in FIGURE 6 that the slots 45 are arranged in two overlapping groups, as at G and G Group G is the primary or initial exhaust group, being the first to exhaust the air fromthe motor as it runs in the direction of the arrow, FIGURE 5,

' while group G as the secondary group, permits final downward: pressure on the governor wearplate54 which I,

, is seated on the governor bottom plate 48;

The plate 48 is slotted radially inwardly at spaced intervals from its periphery as at 80, and these slots are positioned to-pass over the openingsfil) in the top end pressure from the governor chamber progressively into,

the ducts 41 and the slots 42 as the rotor moves in the direction of the arrow, FIGURE 5, from the. point 32.

e The under surface of the plate '35 is relieved, asat 61,

forming a recess connecting the lower ends of'the openings so that fluid pressure entering frorn'the governor chamber past the wear plate 54 and bottom governor plate 35 will be directed through the openings and into the recess 61.

The bottom end plate 37 is also provided with an arcuate relieved recess 62 opening upwardly against the bottom surface of the rotor 31. This recess 62 and the recess 61 in the top end plate 35 are in alignment vertically through the rotor. The recess '62 is a containment for fluid pressure as the slots 42 and ducts pass over it during rotation of the rotor and thus provides a cushion or equalizing means for the fluid pressure exerted in the slots and ducts.

In each of the slots 42 is a free floating rotor blade 43 which has sliding movement radially of the slot and which hasa rear edge preferably curved as at 63 on substantially the same radius as that of the rear wall 64 of the slot, and which has a forward straightedge 65 parallel with and adapted to have contact with the vertical inner cylindrical wall of the liner 30.

plate as the rotor. and governor unitrevolves, and help to maintainan elfective balance of fluid flow at governed rotor speeds.

The governor body 49, to which the top plate 47 is secured by the screws 50, is threaded at Slalong its stem into the'upper threaded portion of the rotor. As the rotor rotates in the direction of the arrow as shown inFIGURE '5, a left handthread is employed at 81, but itislunderthe point 32. I

An axial opening in the body 49 slidably carries a pin 82 (secured therein by a press fit), the upper end of the pin projecting above the body and is secured in a recess 83 in the governor bottom plate by a press fit, the bottom end of the pin 82 engaging a coil compression spring 84 in the opening 85 extending through the rotor spindle. The compression ofthe spring against the pin 82 is adjusted by means or" an adjusting screw 86 threaded into the lower end of the rotor spindle. I

It will be seen from the above descriptionthat as the rotor and governor unitbegin to operate under the influ ence of the high pressure incoming fluid, centrifugal force tends to draw the governorweights 51'outwardly about their axes defined by the weight pins 52.

In order that the several units, i.e., the rotor-governor 7 unit, the top and bottom end plates 35 and 37, respectively, and the rotor liner 30 may be properly positioned and assembled together in exactoperating alignment, at locating and positioning pin 67 is inserted into aligned openings in these'parts, the top of the pin being inserted in an opening 68 in the housing 1. The, pin is prevented from emerging downwardly bythe bottom cap 69 which is held in place by a lock ring 70 in an annular-groove '71 in the housing '1. Set screws 72 in the bottom cap may be employed to exert a pressure against the cap69 and the lock ring 70, I

A rotary tool such as a grinding wheel, sander or wire brush, indicated at 73 is secured on the lower threaded end of the hollow spindle or shaft 33 by means of a nut and washer 74-75 which, when tightened, locks the tool against the wheel collar 40 which is also threaded on the t The governor mechanism includes a governor top. plate p 47 carryinga plurality of pivoted weights 47 a free floating governor bottom plate 48-and a governor body 49, the top plate 47 and the body 49 being secured together by screws 50. The governor top plate 47 is provided with a plurality of radial inwardly extending recesses 51 within 7 which are pivotally'carried governor weights 47' eccentrically mounted on the. pins 52. These weights are Sincethe weights are relieved, their center of gravity will be located above the pins and the weights under the action of centrifugal forceand moving outwardly and downwardly will apply a downward force on the governor wear plate 54 which is seated on the governor bottom plate 48, thus tending to move the governor bottom plate downwardly but such downward movementis resisted by the spring 84 through the pin 82 which bears upon the upper end of the spring 84. This downward movement of the governor bottom plate under the influence of the governor weights decreases the air gap between its lower surface and the upper surface of thetop end plate 35, thus restricting the how of fluid pressure through. the inlet bores 6t ofthe upper end plate and to the rotor.

When a forcebalance is reached between the action of the governor weights and the reaction of the spring 84,

the top plate 47. will settle, and maintain a constant orifice or space through which the incoming fluid pressure to the rotor can be metered and thus control the r.p.m.- of the rotor. It is understood that the above describes the action whenflthe motor has reached an idling speed WhlCh will be maintained until a load is applied to the motor. The application of a load will'reduce the speed I (ofthe motor which of course reduces the centrifugal force exerted upon the. governor weights, allowing the bottom plate 48 to move upwardly in response to the compression force of the spring '84; As a resultof this action, the air gap between the governor bottom plateand the top end plate 18 increased which allows more incoming fluid pressure to flow to the motor to maintain its power output.

The idlingspeed of the motor is conveniently adjustable hy resetting the governor adjusting screw 86. In this connection, a lock screw may be inserted in the lower end of the spindle to abut and lock the set screw $6 in its adjusted position. I

The dead hollow handle or grip 4, illustrated in section in FIGURE 1, also serves as a convenient lubricant reservoir and is removably threaded onto the boss 37 radially disposed on the housing 1 to provide an oil reservoir 88 between the boss and the outer end of the handle. The outer end of the handle has a filler opening plugged at 89 and the boss 87 has an oil feed opening or duct 90 in which a wick-like packing 91 and an oil feed control screw $2 are inserted. A restricted duct or orifice 93 communicates with the interior of the governor chamber 46 and with the duct 90 to feed oil to the chamber 46. The flow of oil into the chamber is controlled by turning the screw 92 in either direction or it can be entirely out ofi by tightening the screw against the end of the boss 87.

In use the invention may be described as follows:

When a source of fluid pressure, such as compressed air, is connected to the inlet bushing in the handle 3 with the throttle valve in closed position, air is prevented from entering the motor and the tool is inoperative.

To start the tool, the valve control plunger 26 is pushed axially inwardly (FIGURE 5) which action causes the plunger to move to the right as it rides along the inclined or cam surface 22, thus unseating the valve 6 and allowing fluid pressure to enter the governor chamber 46 through the duct 15. With the governor unit in its maximum open position under pressure exerted by the spring 84-upon the pin 82, the maximum volume of air enters the motor to start the rotor 31.

The flo-"w of air pressure from the governor chamber to the motor follows a path between the governor bottom plate 48 and the upper face of the top end plate 35 thence through the openings 60 and along recess 61 into the rotor bores 41 and slots 42 behind the blades. The live air then will travel through slots 44 and into the pockets formed between the rotor and the liner 30 and the rotor blades 43.

Since the rotor is located eccentric to the bore of the liner 30 and has minimum clearance with the liner at 32, the volume of the pockets between adjacent blades Will vary from a minimum just beyond the point 32 and the first blade in a clockwise direction, as in FIGURE 5, which represents the intake pocket, to the next pocket between the said first blade and the next blade which represents the expansion pocket. Following the blades in order in a clockwise direction, the next pocket may be defined as the working pocket, while the final pocket represents the exhaust position of the rotor wherein this pocket opens first to the exhaust slots in group G and then into the slots in group G in the liner 36. From the outer surface of this portion of the liner, the air may be exhausted through openings in the housing (not shown).

With the flow as described above and due to the eccentric mounting of the rotor in the liner, it will be seen that the differential in air pressure on two adjacent rotor glades which are presenting varying areas for the air pressure to react upon, constitutes the force that causes rotation of the rotor.

The air inlet, cut-0E and expansion timing is controlled by the design and location of the inlet openings to the rotor, while the exhaust timing and the-exhaust passages are located and designed for maximum efficiency with the minimum use of air.

Various changes may be made in the details of construction and arrangement of parts of the invention without departing from the spirit thereof or the scope of the appended claims.

I claim:

1. In a pneumatically operated tool, a housing, -a liner in the housing, a rotor rotatable in the liner, means for communicating fluid pressure to the rotor, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of air to the rotor, a governor carrier body secured to the rotor, said governor means including a pair of relatively movable governor plates arranged in axially spaced relation, an intermediate plate loosely disposed between said spaced plates, and centrifugally responsive means on one of said paired plates for pressing said intermediate plate into facial con-tact with the other of said paired plates, and means for exhausting spent fluid pressure from the tool.

2. In a pneumatically operated tool, a housing, a liner in the housing, a rotor rotatable in the liner and mounted therein with its axis of rotation eccentric to the axis of the rotor liner, means for communicaitng fluid pressure to the rotor, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of air to the rotor, a governor carrier body secured to the rotor, said governor means including a pair of relatively movable governor plates arranged in axially spaced relation, an intermediate plate loosely disposed between said spaced plates, and centrifugally responsive means on one of said paired plates for pressing said intermediate plate into facial contact with the other of said paired plates, and means for exhausting spent fluid pressure from the tool.

3. In a pneumatically opeated tool, a housing, a liner in the housing, a rotor rotatable in the liner, means for communicating fluid pressure to the rotor, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of air to the rotor, a governor carrier body secured to the rotor, said governor means including a pair of relatively movable governor plates arranged in axially spaced relation, an intermediate plate loosely disposed between said spaced plates, and centrifugally responsive means on one of said paired plates for pressing said intermediate plate into facial contact with the other of said paired plates, means operating through said governor carrier body for exerting a selected axial pressure against and toward said governor means to control the volume of fluid pressure passing into the rotor, and means for exhausing spent fluid pressure from the tool.

4. In a pneumatically operated tool, a housing, a liner in the housing, a rotor rotatable in the liner and mounted therein with its axis of rotation eccentric to the axis of the rotor liner, means for communicating fluid pressure to the rotor, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of air to the rotor, a governor carrier body secured to the rotor, said governor means including a pair of relatively movable governor plates arranged in axially spaced relation, an intermediate plate loosely disposed between said spaced plates, and centrifugally responsive means on one of said paired plates for pressing said intermediate plate into facial contact with the other of said paired plates, means for exhausting spent fluid pressure from the tool, and means operating through said governor carrier body for exerting a selected axial pressure against and toward said governor means to control the volume of fluid pressure passing into the rotor.

5. In a pneumatically-operated tool, a housing, a liner in the housing, a rotor rotatable in the liner, means for communicating fluid pressure to the rotor, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of air to the rotor, a governor carrier body secured to the rotor, said governor means including a pair of relatively movable governor plates arranged in axially spaced relation, a wear plate loosely disposed between said spaced plates, centrifugally responsive means on one of said paired plates for pressing said Wear plate into facial contact with the other of said relatively movable plates to urge it into the path of the fluid pressure entering the rotor, said centrifugally responsive means including a plurality of pivoted weights eccentrically and radially mounted in said one paired plate to exert a pressure against said Wear plate and said other paired plate in response to a centrifugal force applied to said governor whereby to control the flow of fluid pressure to the rotor, and means for exhausting spent fluid pressure from thetool.

6. In a pneumatically operated tool, a housing, a liner in the housing, a rotor rotatable in the liner, means for communicating fluid pressure to the rotor, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of air to the rotor, a governor carrier body secured to the rotor, said governor means including a pair of relatively movable governor plates arranged in axially spaced relation, a wear plate loosely disposed between said spaced plates, centrifugally responsive means on one of said paired plates for pressing said'wear plate into facial contact with the other of said relatively movable plates to urge it and I said other plate into the path of the fluid pressure entering the rotor, said centrifugally responsive means including a plurality of pivoted weights eccentrically and radially mounted in said one paired plate to exert a pressure against said wear plate and said other paired plate in response to a centrifugal force applied to said governor whereby to control the flow of fluid pressure to the rotor, said Weights each being relieved to raise its center of gravity for effective downward pressure contact with the wear plate under the influence of centrifugal force, and

means for exhausting spent fluid pressure from the tool.

7. A fluid pressure operated tool including a housing, a governor chamber and a rotor chamber in said housing, a rotor eccentrically and rotatably carried in said last chamber, a fluid pressure inlet to said first chamber, ducts connecting said chambers to communicate fluid pressure to said rotor, centrifugally responsive governor means in the governor chamber and rotatable with said rotor, fluid pressure volume control means responsive to said governor to thereby control the rate of rotation of the rotor, said last named means comprising a pair of relatively movable governor plates arranged in axially spaced rela-' tion in the path of movement of fluid pressure from said governor chamber to the rotorchamber and directly responsive to said governor means to regulate and control the volume of fluid pressure passing into said rotor chamher, and means for exhausting spent fluid pressure from the rotor chamber.

8. In a pneumatically operated tool, a housing, a rotor rotatable in the housing, a governor chamber in the housing, a fluid pressure inlet in the governor housing, means for progressively communicating fluid pressure from the governor chamber to the rotor, said means comprising a series of openings therebetween, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of fluid pressure to the rotor, a governor carrier body secured to and rotatably with the rotor, said governor means including a pair of relatively movable axially spaced apart governor plates extending radially closely toward but spaced at their circumferences from the wall of the governor housing to provide a passageway for fluid pressure to said series of openings into the rotor, centrifugally responsive means on one of the paired plates for exerting pressure on the other of said plates whereby to vary the volume of fluid flow into said openings, and means for exhausting spent fluid pressure from the tool.

9. In a pneumatically operated tool, a housing, a rotor rotatable in the housing, a governor chamber in the housing, a fluid pressure inlet in the governor housing, means for progressively communicating fluid pressure from the governor chamber to the rotor, said means comprising an opening therebetween, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of fluid pressure to the rotor, a governor carrier body secured to and, rotatable with the rotor, said governor means including a pair of relatively movable axially spaced apart governor plates extending radially closely toward but spaced at their circumferences from the wall of the governor housing to provide a passageway for fluid pressure to said opening into the rotor, centrifugally responsive means on one of the paired plates for exerting pressure on the other of said plates whereby to vary the volume of fluid flow into said opening, and means for exhausting spent fluid pressure from the tool.

10. In a pneumatically operated tool, a housing, a roto rotatable in the housing, a governor chamber in the housing, a fluid pressure inlet in the governor housing, means for progressively communicating fluid pressure from the governor chamber to the rotor, said means comprising an opening therebetween, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of fluid pressure to the rotor, a governor carrier body secured to and rotatable with the rotor, said governor means including a pair of relatively movable axially spaced apart governor plates extending radially closely toward but spaced at their-circurnferences fromthe wall of the governor housing to provide a passageway for fluid pressure to said opening into the rotor, the lowermost plate being slotted radially inwardly from its peripheral edge, said slots adapted to pass across said opening communicating the governor chamber with the rotor as the rotor rotates, centrifugally responsive means on one of the paired plates for exerting pressure on the other of said plates whereby to vary the volume of fluid flow into said opening, and means for exhausting spent fluid pressure fromthe tool.

11. In a pneumatically operated tool, a housing, a rotor rotatable in the housing, a governor chamber in the housing, a fluid pressure inlet in the governor housing,

- means for progressively communicating fluid pressure from the governor chamber to the rotor, said means comprising an opening therebetween, governor means rotatable with the rotor and operable in response to the rate of rotation of the rotor to vary the volume of fluid pressure tothe rotor, a governor carrier body secured to and rotatable'with the rotor, said governor means including a pair of relatively movable axially spaced apart governor plates extending radially closely toward but spaced at their circumferences from the wall, of the governor housing to provide a passageway for fluid pressure to, said opening into; the rotor, centrifugally responsive means on one of the paired plates for exerting pressure on the other of said plates whereby to vary the volume of fluid flow into said opening, and means for exhausting spent fluid pressure from the tool, said last named means including a plurality of elongate radially disposed exhaust openings in said rotor anda plurality of staggered ex haust slots in the rotor chamber adapted to be traversed by said radial openings during rotation of the rotor.

References Cited in the tile of this patent UNITED STATES PATENTS Karlen Apr. 6, 1954

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