US2830560A

US2830560A - Air-operated hand tool

Info

Publication number: US2830560A
Application number: US538603A
Authority: US
Inventors: Roland E Doeden
Original assignee: DOEDEN TOOL CORP
Current assignee: DOEDEN TOOL CORP
Priority date: 1955-10-05
Filing date: 1955-10-05
Publication date: 1958-04-15
Anticipated expiration: 1975-04-15

Description

April 1958 R'. E. DOEDEN 2,830,560

AIR-OPERATED HAND TOOL Filed Oct. 5, 1955 2 Sheets-Sheet 1 Izzy/Z7 11/7/11.

INVENTOR.

Z OLA/VD l. OOEQEN A TT'O BAA 5Y5- hired dtates arent ititice Patented Apr. 1.5, 195 8 AIR-OPERATED HAN D TOOL Roland E. Doedcn, Sherwood, Ohio, assignor to Doeden Tool Corp., Sherwood, Ohio, a corporation of Ohio Application Gctobcr 5, 1955, Serial No. 538,603

1 Ciaim. (Cl. 121--34) The present invention relates generally as indicated to an air-operated hand tool, and more particularly to a high speed rotary hand tool having a drive shaft driven by a coaxially disposed air rotor.

It is a primary object of this invention to provide a hand tool of the character indicated which is small and compact so as to be conveniently held in the hand and easily manipulated.

It is another object of this invention to provide a hand tool characterized in that the air motor therefor is a self-contained assembly which is clamped in the housing or handle of the tool.

It is another object of this. invention to provide an airoperated hand tool having novel means for mutiling or silencing high-pitched whistle which would otherwise result from the high-speed operation of the tool.

It is another object of this invention to provide an air-operated hand tool having a novel form of control valve mechanism for controlling the flow of air from a pressure inlet port into the inlet port of the air motor.

It is another object of this invention to provide a hand tool in which an end of the self-contained air motor is formed with an annular recess which registers with the air pressure supply port in the housing irrespective of the rotary position in which the air motor is clamped in the tool housing.

It is another object of this invention to provide a hand tool in which a single threaded thimble functions to clamp the air motor in the tool housing and serves as a mount for an air deflector hood which causes the. exhaust air from the motor to how longitudinally atong the drive shaftand along the tool secured thereto so as to blow dirt or other foreign matter away from the work ing area of the tool.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claim, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, how ever, of but a few of the various ways in which the principle of the invention may be employed.

' In said annexed drawings:

Fig. 1 is a diametral longitudinal cross-section view showing one form of the present invention in which the air supply control valve is actuated by a pivotal lever which is squeezed in the hand during use of the tool;

Figs. 2 and 3 are transverse cross-section views taken substantially along the lines 2--2 and 3-3, Fig. 1, respectively;

Fig. 4 is a fragmentary cross-section view of.- another form of the invention wherein the air control valve is push-button actuated, the push-button being arranged to be locked in air flow permitting position;

.Fig. 5 is an elevation view of the push-button mechanism as viewed from the righthand side thereof; and

Fig. 6 is a cross-section view of still another embodiment of this invention showing an angle drive unit secured to the drive shaft of the handheld'tool.

Referring now more specifically to the drawings, and first to the form of the invention illustrated in Figs. 13, the same comprises generally cylindrical housing or handle 1 formed with an air pressure inlet port 2 at one end, a cylindrical cavity 3 at the other end, a transverse bore t adjacent the inlet port 2, and passages 5 and 6 leading to the cross bore 4 from the inlet port 2. and from the bottom of the cavity 3, respectively.

Fitted into said cross bore 4 is a valve mechanism which comprises a tubular ported bushing 7 which'is preferably press-fitted into the cross bore and which slidably mounts a valve member 8 therein, the valve member extending through said bushing 7 for actuation as by means of a lever 9 which is pivotally connected on pin 10 adjacent the rear end of the housing 1.

Said valve member 8' is formed with a packing ring,

groove which has opposed parallel conical walls disposed at approximately a 45 angle with respect to the axis of said valve member in which groove an O-ring 11 is mounted. As apparent, when said valve member 8 is pressed upwardly, as shown in Fig. 1, the O-ring 11 seats against the bottom inside corner of the bushing 7 to thus prevent flow of air from the inlet port into the housing cavity. When said valve member is moved downwardly by squeezing the lever 9 against the housing 1, air flow is permitted, and the lips of the valve memberat the conical walls of the O-ring groove serve to protect the O-ring 11 from extrusion, since the air flow is directed around the outside of the O-ring and across the open gap formed between the aforesaid lips.

The valve member 8 is resiliently urged and held in seated position by means of a spring 12 which is compressed between said valve member 8 and a spring retainer and regulator member 14, said regulator member 14 being formed with a screw driver slot or the like so that it may be rotatably adjusted whereby either of its ports 15 may be aligned or misaligned with the inlet passage 5. Said regulator member 14 is held in place by means of the slotted tubular plug 16 which is threaded into the lower end of the cross bore 4, there being interposed rubber or rubber-like rings 17 and 18 between the regulator 14 and plug 16 and between said plug 16 and housing 1, so as to form fluid-tight seals.

The ring 17, at the same time, serves to frictionally retain the regulator 14 in desired rotary position. It can be seen that air flow through passages 5 and 15 can be regulated to any value from zero to full flow simply by turning the regulator 14 to any position between full misalignment to full alignment of said passage 15 relative to inlet passage 5.

Referring now to the air motor, the same is a complete self-contained assembly 29 which includes a, stator 21 providing an eccentrically disposed chamber 23 around which laminated plastic or like vanes 24 slide to form displacement cavities in well known manner. In this particular example of the tool, there are four vanes 24 radially slidably carried by a centrally disposed rotor 25. The stator 21 has rings or

motor end plates

26 and 27 secured thereto at opposite ends as by pins 22 in which i the respective

anti-friction bearings

28 and 29 are mounted to support the rotor 25 for free rotationwith respect to the stator assembly comprising the stator 21 and said rings or

end plates

26 and 27, the vanes 24 being of axial length so that the ends thereof are in close proximity to the inner-end surfaces of said rings or end plates 26' and 27.

The outer end of the ring 26 is formed with an annular groove 30 and with passages 31, the latter communicating with passages 31A and circumferential undercut 31B of stator 21 whereby when valve member 8 is unseated air under pressure flows into the chamber 23. Said. annular groove 30 is of diameter such that in all rotary portions of the

stator assembly

21, 26, 27, said annular groove will register with the passage 6 in the bottom of the cavity 3.

The periphery of the stator 21 is formed with exhaust passages preferably in the form of transverse slots 32, and furthermore said stator 21 and ring 27 are formed with a plurality of peripheral, axially extending slots 34 for flow of the exhausted air from the motor therethrough.

The outer end of the cavity 3 in housing 1 is internally threaded for engagement by a thimble which functions (1) to clamp the air motor assembly 24} in the housing 1 to seal the stator ring 26 against the bottom of the cavity, the clamping pressure being applied through the outer race of the anti-friction bearing 29; (2) to constitute a mufi'ler or silencer to eliminate high-pitched whistling which otherwise would occur if the exhausted air were allowed to pass directly into the atmosphere through the

slots

32 and 34, the silencing being eifected by means of the porous sintered bronze ring 36 which is fitted into an annular recess in the end of said thimble 35; and (3) to constitute a mounting means for an airdeflecting hood 37 which herein is of tubular form and arranged to cause the exhausted air to flow longitudinally along the chuck 33 and along a tool adapted to be gripped by the chuck.

The chuck 38 aforesaid may be of any well known form, but is illustratively shown herein as comprising a chuck body 39 threaded onto the end of the rotor shaft 25 in abutment with the inner race of the anti-friction bearing 29. A contractible collet 40 alternately slotted from its opposite ends is fitted into the end of the chuck body 39. Frusto-conical cam surfaces in the body 39 and on the collet 40 cooperate to contract the latter when forced axially endwise into the chuck body 39. The means for thus axially moving the collet 46 comprise a two-part nose piece assembly, the part 41 of which engages the outer end of the collet and the part 42 of which engages a shoulder of the part 41 and has threaded engagement with the chuck body 39.

In the use of this tool, an air supply hose is connected to the inlet port 2 of the housing 1 and the desired tool, such as a small, pointed grinding element, for example, is mounted in the chuck 38. The housing 1 is then grasped in one hand and operation is started by squeezing the lever 9 toward the housing 1, thus permitting air flow into the air motor in a manner already described.

In a tool which is 4 /2" to 4% in length and with a housing of approximately 1%" diameter and an air pressure supply of 90 p. s. i., the rotor 25 has a free running speed of 30,000 R. P. M. and a working speed, under load, of about 15 to 20,000 R. P. M.

It is to be noted that the thimble 35 has exhaust ports 43 therethrough, and in one example there are eight such ports equally spaced so as to provide a uniformly flowing annular stream of air longitudinally along the chuck 33 and along the tool mounted therein toward the work area.

The embodiment of the invention shown in Figs. 4 and 5 is essentially the same as that shown in Figs. l'to 3, except that the air deflector hood 45 may be shortened so that a larger grinding wheel or cutter may be used and except that the valve bushing 46 is formed with a bayonet-slot formation 47 at its upper end which cooperates with the radially projecting ends of a pin 48 which secures the push-button 49 to the upper end of the valve member 50.

In the position of the parts illustrated in Fig. 4, the inlet port is closed by the seating of the O-ring 11 against the bottom inside corner of the bushing 46. When it is desired to use the tool, the operator pushes the button 49 downwardly and then turns the same to lock the valve member 50 in unseated position, whereupon the tool may be continuously used without having to manually hold the button 49 in.

Referring now to Fig. 6, there is shown therein an angle drive unit 55 secured to the rotor drive shaft 25. Said angle drive unit 55 includes an angle housing 56 of which one leg is held against the outer race of anti-friction bearing 29 through a nut 57 having threaded engagement with the thimble 58, said leg having a peripheral groove therearound in which is disposed a split ring 59 through which such holding of the housing 56 is accomplished. in this case, the thimble 58 need not be provided with the mufiler 36 and discharge ports 43 as before; instead, the leg of the angular housing 56 is formed with a groove 60 for exhaust of air from the air motor assembly 20.

Threaded onto the end of the rotor shaft 25 is a bevel pinion element 61 which meshes with a bevel gear 62, the latter in turn being keyed to a drive shaft 63 journalled in the other leg of the angular housing 56 as by means of spaced-apart

anti-friction bearings

64 and 65. The lower end of said drive shaft is formed as is the chuck body 39 in Fig. 1 so that atool mounted therein will be disposed at right angles to the axis of the handheld tool.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in the following claim, or the equivalent of such, be employed.

1 therefore particularly point out and distinctly claim as my invention:

A hand tool comprising a housing formed with an air inlet port at one end, a cylindrical cavity at the other end, a transverse bore adjacent such one end, and passages leading into said bore respectively from said inlet port and from the bottom of said cavity; a valve mechanism in said bore including a movable valve member adapted to be manually actuated from seated to unseated position to permit air flow from said inlet port into said cavity; an air motor assembly removably fitted into said cavity; said assembly comprising a tubular stator having an eccentrically disposed bore and an opening through the wall thereof communicating said bore with said cavity, motor end plates non-rotatably secured at the respective ends of said stator and provided with bearings coaxially disposed with respect to said cavity, one end plate engaging the bottom of said cavity and formed with an annular recess that registers with the aforesaid passage in the bottom of said cavity in all rotary positions of said motor assembly in said cavity and with a passage leading from such recess into such eccentrically disposed bore, the other end plate and corresponding end of said.

stator being formed with an axially extending peripheral slot for exhaust of air from said cavity, a rotor journalled in said bearings, and a plurality of sliding vanes radially movably carried by said rotor and adapted to engage the wall of such bore whereby said rotor is rotated responsive to movement of said valve member to unseated position; a chuck mounted on said rotor to project axially beyond the mouth of said cavity; a thimble threaded in said housing and arranged to engage the bearing of said other end plate to clamp said motor assembly against the bottom of said cavity; said thimble constituting an extension of such exhaust slot; and an air deflector hood screwed onto said thimble to form an annular continuation of such exhaust slot extension whereby air exhausted from said air motor assembly flows axially along said chuck and toward the work area of a tool adapted to be held by said chuck.

References Cited in the file of this patent UNITED STATES PATENTS