US1940024A - Portable tool - Google Patents

Description

Dec. 19, 1933. E. H. sHAFF PORTABLE TOOL Filed April 7. 1931 l .//ln 7427/2 @u Ernest H. 5

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IIE-1 7Patented Dec. 19, 1933 UNITED STATES 1,940,024 PORTABLE Toor.

Ernest H. Shari, Grand Haven, Mich., assigner William H. Keller, Inc., Grand Haven, Mich., a

corporation of Michigan Application April 7, 1932. Serial No. 603,756

4 Claims. (Cl. 121-34) The invention relates generally to portable pressure fluid operated tools and more particularly to such tools of the rotary type adapted for grinding, polishing and like operations.

The primary object of the present invention is to provide an improved tool of this character of elongated form with a processing tool at one end of the casing and having-a speed governor of improved and ,simplified construction with 1o the parts thereof distributed to avoid undue concentration of weight at one end of the tool whereby to improve the balance of the tool.,

Another object is to provide such a device K having a centrifugally operated speed governor constructed to permit the mounting of bearings for the motor shaft immediately adjacent to the ends of the rotor, reduce the over-all length of the tool and simplify the venting of the casing.

Another object is to provide such a portable tool having an improved speed governor constructed without springs.

Another object is to provide a tool of this character embodying a novel sub-division of the parts thereof whereby to facilitate and reduce the cost of manufacture and assembly.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawing which illustrates one form of a tool embodying the features of the invention, and in'which:

Figure 1 is a longitudinal sectional view taken irough a tool embodying the features of the vention, the section being taken along the line 1-1 of Fig. 3.

Fig; 2 is a side elevational view of the motor cylinder.

Fig. 3 is a transverse sectional view, taken along the line 3-3 of Fig. 1.

Fig. 4 is an enlarged fragmental sectional view taken longitudinally through the motor shaft and showing the construction of the speed governor.

Fig. 5 is a fragmental sectional view of one i handle taken along the line 5-5 of Fig. 3.

In the form illustrated herein the invention is embodied in a portable pressure fluid operated tool of elongated form having a substantially cylindrical casing 10 with an enlarged portion 11 constituting a motor housing, a handle 12 atfoneA end of the casing and a processing tool such las a grinding wheel 13 carried at the other end of the casing a substantial distance from the handle 12. Within the casing 10 a shaft 14 is rotatably mounted with one end projecting from the casing and carrying the grinding wheel 13. Adjacent tothe grinding wheel 15, the shaft 14 is supported by a bearing 144EL and intermediate the bearing 1iik and the housing section 11 the casing has a cylindrical section 15 of reduced diameter adapted to be grasped by the operator to support the tool and guide the grinding wheel 13. Thus an operator may support the tool at spaced points by grasping the handle 12 in one hand and the reduced casing section 15 in the other hand to apply the grinding wheel 13 to the work.

To facilitate the construction and maintenance of the tool, the motor housing 11 has a removable head or end wall 16 which is of relatively great .thickness and carries the handle 12, the end wail 16 being secured to the housing 11 by bolts 17 and nuts 18. Within thev housing 11 a pressure uid operated motor of the eccentrically walled chamber type is mounted and for this reason the housing 11 is eccentrically located with relation to the reduced section 15 and the shaft -14. 'Ihe parts of the motor are preferably formed entirely separately from the housing 1l, a cylinder 19 of substantially smaller diameter than the housing 11 being insertable. endwise into the housing when the end wall 16 is removed. Flanges 20 at opposite ends of the cylinder 19 engage the housing to position the cylinder laterally therein, and notches 21 formed in the flanges 20 engage the bolts v17 to prevent rotationof the cylinder within the housing.

The ends of the cylinder 19 are closedby plates 22 which surround the shaft 14 and have openings formed therein for the bolts 17. Within the cylinder 19 a rotor 23 concentric with and keyed on the shaft 14 has blades 24 mounted in radial slots 25 formed in the rotor for movement i'nto contact with the inner surface of the cylinder 19. Due to the eccentric positioning ofthe rotor 23 with relation to the cylinder 19, the rotor is substantially in contact with the cylinder at one side thereof. In the rotation of the rotor 23 in the direction of the arrow (Fig. 3) a pressure chamber 26 is for'med between the rotor, the cylinder and one of the blades 24, into which chamber pressure fluid is discharged through a plurality of ports 27 so as to cause movement of the rotor. After the blade 24 at the end of the pressure chamber 26 has traveled substantially 180 past the openings 27, it passes over a plurality of exhaust ports 28 arranged in two sets and formed in the cylinder 19 (Figs. 2 and. 3) so that the pressure fluid exhausts into the space between the cylinder 19 and the housing 11 to escapethrough vents 29 (Fig. 3) formed in the housing 11.

Pressure fluid is supplied to the ports 27 through a longitudinal bore 30 formed in arib 31 extending longitudinally along the outside of the cylinder 19. At the end adjacent the handle 12 the bore 30 registers with an aperture 32 formed in the plate 22 and communicates with a passage 33 formed in the end wall 16. 'Ihe supply ofthe pressure fluid to the-passage 33 from an inlet passage 34 is controlled by a normally closed valve 35 actuated by a lever 36 in a conventional manner. y

Speed governing means is provided for the motor and in accordance with the present invention this means is constructed to facilitate manufacture and assembly of the tool and to produce a tool of improved balance. 'I'he speed governing means is also arranged to' permit the shaft 14 to be supported immediately adjacent to the end plates 22 by means of anti-friction bearings 37 and 38 carried in suitable recesses inthe removable end wall 16 and in a fixed end wall 39 at the opposite end of the motor housing. With this in view, the present speed governing means comprises a valve 40 interposed between the passages 33 and 34 and. located at one end of the motor in the removable end wall 16, and a centrifugally operated device 41 mounted on the shaft 14 at the other end of the motor and operable to control the valve 40.

The valve 40 is preferably of cylindrical form and is rotated during operation of the tool to insure free movement of the valve in a longitudinal direction to vary the supply of pressure fluid to the motor. 'I'he valve 40 is therefore mounted in a bearing sleeve 42'screw threaded into the end wall 16 coaxially with the shaft 14 and communicating at its open inner end with a passage 35a which is -controlled by -the main valve 35. About the sleeve 42 an annular chamber 43`is formed communicating with the passage 33, and pressure fluid passes from within the sleeve 42 into the chamber 43 through transverse ports 44 formed in the sleeve, the effective area of the ports 44 being controlled by the longitudinal position of the valve 40.

At its end adjacent to the bearing 37, the valve 40 has Aa transverse slot 45 formed thereinl (Fig. 4) to receive a slotted tonguev 46 formed on the end of a rod 47, the valve 40 having a pin 48 extending across the slot 45 and through the slot formed in the tongue 46 to form a universal connection between the rod 47 and the valve 40. The r`d 47 extends through a longitudinal bore 49 formed in the shaft 14 and at its other end the rod is operatively associatedl with the centrifugal speed governing device 41.

The valve actuating device 41 comprises Weights 50 mounted on bell cranks 51 which are pivoted at 52 in'radial slots 53 formed in the shaft 14 adjacent to the bearing 38. The bell cranks 51 have arms 54 extending toward each other'and into the bore 49 so that the arms may bear against the end of the rod 47 to actuate the same. In the present instance the arms 54 extend into a transverse slot 55 formedin the rod so as to transmit rotation to the rod 47 and thereby cause the bearing sleeve 42.

As the speed of the motor increases the weights 50 swing outwardly away from the axis of the shaft 14 and to provide clearance forl the movement of the weights, the casing 10 is er1- valve 40 to rotate in itslarged as at 56 Aadjacent 'to the fixed end Wall v39 of the motor housing. When the weights 50 and cause the speed of the motor to be reduced.

Return movement of the valve 40 and the weights 50 is obtained by the action of the pressure fluid on the end of the valve 40 so that a speed governing device is provided which operates without the use of springs. handle 12 has been removed, the valve 40 and its bearing sleeve 42 are readily accessible for removal, and by substitution of valves having different end areas, various motor speeds may be obtained, it being understood that the tool is normally operated from a relatively constant pressure source of motive fluid.

By making the major portion of the rod 47 somewhat smaller than thev bore 49, pressure fluid leaking into the reduced section 15 of the casing may be vented through the slots 53 and the bore 49 of the shaft 14 into a recess 37 in which the bearing 37 is mounted. To relieve pressure in this chamber an angularly positioned bore 57 (Fig.v 5) in the end wall 16 extends from the recess 37 into a longitudinal bore 58 through which one of the bolts 17 extends. The bore 58 is enlarged as at 58"L and the plate 22 has an aperture 59 therein slightly larger than the bolt 17 to permit pressure to exhaust into the space between the cylinder and the casing and thence through the exhaust ports 29.

From the foregoing description, it will be apparent that the invention provides a portable tool having a, speed governing device which, by reason of the novel distribution of its parts, produces a tool having an improved balance. It will also be seen that the use of a rotating valve for the speed governing device causes the valve to move freely and to be accurately re sponsive to the centrifugal weights. The distribution of the ,parts of the speed governing device permits the mounting of the bearings closely 'adjacent to the ends of the motor so as to insure an accurate relationship between the parts of the motor, While the provision of a longitudinal passage through the shaft enables the casing to be vented in a simple manner.

I claim as my invention:

1. A device of the character described comprising an elongated casing providing a motor housing with a handle at one' end of the housing and an elongated portion of reduced diameter projecting from the other end of the housing, a pressure iiuid operated motor in said housing having a rotor, a shaft in said housing carrying said rotor, bearings for said shaft at opposite endsof said When the iis housing adjacent to said rotor, vone end of said 1 shaft extending through saidA reduced portion and out of the end thereof to receive a tool, a third bearing for said shaft in said reduced portion of the casing adjacent to the end of the shaft, a passage in said handle for conducting motive uid to the motor, a valve in controlling relation to said passage alined with and movable axially with relation to said shaft, shiftable gov--A ernor weights rotatable with and mounted on said shaft beyond the bearing at lthe other end of the rotor, and means operatively connecting said weights and said valve.

A2. lA portable pressure 'fluid operated tool comprising an elongated casingproviding a motor housing with a handle portiorimt one end of the housing, a shaft extending out of said casing at the other end of said casing to receive a tool, al rotor for the motor on said shaft within said housing, a passage through said handle and to said-housing for conducting pressure fluid for operating said motor, and speed governing means comprising a valve member in said handle in controlling relation to said passage, a centrifugall'y actuated device on said shaft at the other end of said housing, and means operatively connecting said device and said valve member.

3. A portable pressure fluid operated tool comprising an elongated casing providing a motor housing and a handle at one end of said housing, a motor in said housing having a shaft extending beyond the other end of said housing and out of said casing to receive a tool, a bearing for said shaft at each end of said motor, a e in said handle for conducting motive fluid to the motor. and speed governing means for said motor comprising a valve member mounted in said casing at one end of said motor in controlling relation to said e, and eentrlfugally shiftable weights operatively associated with said valve member and mounted on said shaft beyond the bearing at the other end of the motor.

4. A device of the character described comprising in combination a motor housing, a rotor therein, a hollow shaft rotatably supported in said housing and upon which said rotor is xed, pressure uid supply means for said motor including a rotatable valve member alined with said shaft at one end of the shaft and shiftable longitudinally to control the speed of the motor, a rod shiftable longitudinally within said shaft to move said valve member and having a rotation-transmitting connection with said member, governor weights mounted on said shaft at the other end of said rotor for rotation with the shaft and for radial shifting movement, and meansV connecting said weights with said rod to shift the same when said weights move radially and to rotate said rod with the shaft.

ERNEST H. SHAFF.

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