US2993391A - Boring tool or the like - Google Patents

Description

July 25, 1961 w. E. RANEY 2,993,391

BORING TOOL OR THE LIKE Filed July 13. 1959 2 Sheets-Sheet 1 WILLIAM E. RANEY a ATTORNEYS July 25, 1961 w. E. RANEY BORING TOOL OR THE LIKE 2 Sheets-Sheet 2 Filect July 13, 1959 INVENTOR.

WILLIAM E. RANEY Ill am, my?

ATTORNEYS United States PatentO 2,993,391 BORING TOOL OR THE LIKE William E. Raney, 20080 Frazier Drive, Rocky River, Ohio Filed July 13, 1959, Ser. No. 826,727 20 Claims. (Cl. 77-33.5)

This invention relates, as indicated, to a boring tool or the like and more particularly to a tool actuating mechanism and control unit therefor, which comprises improvements in the mechanism of the character disclosed in my Patent No. 2,648,238, dated August 11, 1953, in which the rotary and axially reciprocable tool carrying shaft constitutes the rotor or secondary winding of an electric motor.

In the aforesaid patent construction there resulted an automatic reduction in the speed of rotation and torque of the drive shaft in accordance with the depth of the cut, drilling or like operation which was being performed as the result of the rotor of the electric drive mechanism moving axially away from the stator or primary winding thereof. This automatic reduction in the speed or torque of the cutting tool resulted in somewhat slower operation or reduced rates of feed and, moreover, the uniformity of the cutting operation was reduced to some extent.

Moreover, as a result of the stator and rotor in my aforesaid patent being of equal length, the solenoid efiect on the rotor increased as the end of the rotor approached the center of the stator Where the elfect would be at a maximum. This increasing solenoid effect coupled with the decreasing torque reduced the efficiency of the unit and necessitated fine adjustment of the axial feed control to compensate for these variables.

Furthermore, in the patent construction the motor and drive shaft continued to rotate on the out-feed or return stroke of the tool, which presented a safety hazard as well as tending to shorten tool life. Moreover, the bearings employed as the main motor bearings were also subject to wear as the result of the axial reciprocation and rotation of the tool-carrying shaft without means being provided to take up such wear.

Accordingly, it is a primary object of my invention to provide a drive motor having an axially reciprocable rotor that will not suffer an automatic reduction in speed or a substantial loss of torque as the tool approaches its maximum in-feed position.

It is a further principal object of my invention to substantially decrease the solenoid effect on the axially reciprocable drive shaft of such tool whereby the tool feed pressure may be more accurately controlled.

It is a further object of my invention to provide a compact, powerful tool in which the rotation of the tool will automatically stop during the out-feed stroke and will remain stopped until the start of the next stroke.

It is a further object of my invention to provide a unique means for accurately judging and adjusting the required bearing pressure on the main shaft bearing between the motor housing and the axially reciprocable rotor-tool shaft.

It is a still further object of my invention to provide an automatic sequence control whereby the tool rotating and feeding apparatus may be cycled through a single operation requiring the operator only to load and unload workpieces and actuate a single start button.

It is yet a further object of my invention to provide an automatic cushioning device to preclude the tool rotor from breaking through the work near the end of the stroke, said cushioning device also being used to assist in the lubrication of the main shaft bearing.

, It is another object of my invention to provide a unique ice actuating piston exhaust means whereby the fluid exhausting therefrom may be utilized to cool the stator and rotor of my electric drive motor.

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 particularlypointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

In said annexed drawings:

FIG. 1 is a generally longitudinal sectional view of my boring tool or the like with parts thereof removed for clarity of illustration;

FIG. 2 is a front end elevation as seen from the left in FIG. 1;

FIG. 3 is a somewhat schematic end elevation as seen from the right in FIG. 1;

FIG. 4 is an enlarged sectional view of my braking mechanism taken generally on the line 4-4 of FIG. 1 with the housing removed;

FIG. 5 is an enlarged top view of my braking actuating mechanism;

lFIG. 6 is an enlarged vertical section of my air control va ve;

FIG. 7 is a top plan view of my air control valve with the solenoid removed; and

FIG. 8 is a schematic wiring diagram illustrating the electrical connections which obtain my sequence of operation.

Referring now to the drawings and more particularly to FIGS. 1 through 3, there is shown a main frame structure 1 which provides a forwardly extending platform on which is mounted an electric drive motor generally indicated at 2 mounted in an elongated housing 3. Although the motor 2 may be a DC. motor or a commutator or slip ring type of motor, it is herein shown as an induction motor comprising a stator or primary winding 4 and an elongated secondary winding or rotor 5 mounted as by a key on main shaft 6 for axial reciprocation within the stator 4. The housing 3 has a front end extension or end bell 7 joined to the main shaft bearing generally shown at 8.

The housing 3 has a rearward extension 9 in which is mounted coupling 10 having therein a main shaft end thrust bearing generally shown at 11. In this manner reciprocation of the coupling sleeve 10 will reciprocate the main shaft 6 having the rotor 5 thereon within the stator 4.

The coupling sleeve 10 is connected by rod 12 with main actuating piston 13 enclosed within air cylinder 14. The cylinder 14 is rigidly mounted on a rearward extension of the housing 9 which forms the rod end of the cylinder and is generally shown at 15. The extension 15 is rigidly secured to the housing and has therein apertures 16 to permit elongated guide rods 17 and 18 to pass therethrough. These rods are threaded into the coupling 10 for reciprocation therewith. Mounted on the ends of the rods 17 and '18 is a cross frame member 19 which is rigidly connected to the rods 17 and 18 by nuts 20.

It will now be seen that piston 13, which is rigidly connected to the coupling 10 by the rod 12, will reciprocate the main shaft 6, the rods 17 and 18 and the end member 19 as a unit.

The end member 19 has a central aperture 21 therein in which is threaded a hollow extension 22. Threaded into the outer end of the extension 22 is an adjustable stop screw 23 which is secured to the extension 22 by means of 3 a nut 24. Secured within the hollow central portion of the extension 22 is an annular stop 25 surrounding a push rod 26 extending therethrough. The push rod 26 extends through theend member 19 through hydraulic reservoir 27 and into a central hollow cylinder 28 concentrically axially mounted within the air cylinder 14. Secured to the end of the push rod 26 is a valve member 29 having a. threaded stop 30 on the end thereof. Surrounding the end of the push rod between the stop and the valve member is a piston sleeve 31 closely fitting within the cylinder 28. It will be. noted that there is a slight amount of play between the members 29 and 30 and 31. When the push rod is moved to the left, as seen in FIG. 1, the valve member will abut the sleeve 39 and in this manner effectively seal the passage of fluid from the left end of the cylinder 28 to the right end of the cylinder, as seen in FIG. 1. However, as the push rod is moved to the left, the sleeve 31 will abut against the stop 36 and in this manner fluid within the cylinder 28 may freely pass through the members 29, 3t and 31. The cylinder 28 is connected through conduits 32 and. 33 to the hydraulic reservoir 27 and a feed valve, generally shown at 34, by means of which the flow of fluid or the like from the left end of cylinder 28, as seen in FIG. 1, may be accurately controlled. This feed valve is a conventional 6 degree taper needle valve which controls the rate of feed from to 50 inches per minute. Ten turns of the adjusting mechanism are equal to a .060" rise of the'needle and in this manner it will be seen that the escape of fluid from the end of the cylinder 28 may be accurately controlled. It will now be seen that as the piston 13 moves to the left, the adjusting stop 23 will abut against the end of the push rod 26 at a predetermined position in the stroke. This will force the push rod to the left, as shown in FIG.

4, causing the members 29 and 31 to abut forming an effective seal or piston within the cylinder 28 and force the fluid Within the cylinder through the valve into the reservoir 27. In this manner the rate of speed of a predetermined final portion of the stroke may be accurately controlled to prevent the tool from breaking through the work as the work becomes thinner. This mechanism is generally of the type illustrated in FIG. 12 of my aforementioned patent.

Connected to the hydraulic or fluid system (usually an oil having lubricating properties) are two fluid lines or conduits 35 and 36 which lead to the main front end bearing 8; These lines or conduits are utilized to keep the main bearing saturated with such lubricating fluid. In this manner the front end bearing will always be lubricated. The main bearing 8 consists of a plurality, as for example six, wedge-shaped bearing members 37 which surround the shaft 6. These wedge-shaped bearing members are secured to a nut 38 which is threaded into bearing housing 39 which constitutes an extension of the end bell 7 of the motor housing 3. In this manner it will be seen that rotation of the nut 38 will move the bearing members 37 axially of the shaft 6. The bearing members will. bear against the inclined inner surface 40 of the bearing housing 39. The bearing members 37 are preferably of the porous or powdered metal type which can be permanently lubricated through the lines 35 and 36. These bearings are generally sold under the trademark Oilite. It will now be seen that the pressure of the bearing members 37 against the shaft 6 may be accurately controlled to reduce radial clearance to a minimum by rotation of the nut 38. In this manner the proper idling load upon the motor may be obtained as the shaft or bearing wears.

The. spindle or shaft has a mounting on the tool end thereof, generally shown at 41, whereby a conventional chuck may be secured thereto so that a proper drilling or cutting tool may be employed therewith. On the other end. of the shaft6 is a conventional thrust bearing similar tothat employed with the operating shaft as disclosed in my aforementioned patent. The thrust bearing comprises I 5,993,391 I g two ball bearings 41 and 42 between the coupling member 10 and the depressed portion of the shaft 6. It will be noted that the coupling member 10 has a central removable portion 43 secured thereto by set screw 44. This removable member 43 may be used to assemble the rod 12 to the coupling member 10.

Mounted on the shaft 6 rearwardly of the rotor 5 is an enlarged portion 45 against which my braking mechanism, generally viewed in FIGS. 4 and 5, is adapted to be clamped. The braking mechanism generally comprises two circular bands. 46 and 47 pivoted about pin 48. Opposite the pivot 48 the members 46 and 47 have extending flanges 49 and 50 which are interconnected by an elongated bolt 51. Between the head 52 of the bolt 51 and the flange 50 there is a compression spring 53 exerting a force tending to separate the head 52 and the flange 50'. Between the. flanges 49 and 50 there is positioned a wedge-shaped member 54. This wedge member has approximately a.15 degree angle on each side and is designed to reciprocate, as. shown in FIG. 5, between an extended and retracted position, it being understood that the flanges 49 and 50 are shaped to conform to the 15 degree sides ofv the wedge member 54. It will now be seen that as the wedge member is extended between the flanges 49 and 50, the brake bands 46 and 47 will separate about pivot 48 releasing the enlarged portion 45 of the shaft 6 for rotation. When the wedge member is retracted, the spring 53 will force the flanges 49 and 50 toward each other and in this manner contracting the brake bands 46 and 47 against the enlarged portion of the shaft. It will be understood that the bolt 51 has a nut 55 on the end thereof which may be adjusted to regulate and thus obtain the desired braking pressure resulting from the expansion of spring 53. The braking members 46 and 47, of course, will employ suitable linings 56 and 57 of a conventional nature. The braking mechanism is mounted on a housing extension 58 of the coupling member 10, it now being seen that the entire braking mechanism reciprocates with the main shaft 6. It will, of course, be understood that the spring 53 may be employed between the nut and adjacent flange if desired as shown in FIG. 5.

The wedge member 54 is actuated by an air piston 59 enclosed within cylinder 60 in the housing 58. The cylinder 60 has a fluid inlet 61 connected by way of an air valve to the main air supply by means of a suitable flexible conduit. Between the rod end of the cylinder and the piston is a suitable compression spring 62. It will now be seen that the piston 59 is a single acting piston which may be moved to the left, as shown in FIG. 1, by air or fluid entering the blind end of the cylinder. This will compress the spring 62 as the piston moves to the left. This will in turn force thewedge member between the flanges 49 and 50, releasing the brake. When the air pressure is released, the spring 62 will move the piston to the right, as seenin FIG. 1, withdrawing the wedge member 54 permitting the spring 53 to apply the braking pressure.

Mounted. beneath and to one side of the wedge member 54 is a micro switch 63 having an actuating arm 64. This arm 64 engages a pivoted spring pressed member 65 which engages a depressed or cam surface 66 on the underside of wedge 54. The wedge 54 has a cam surface 66 which rides over the spring pressed member 65 which will in turn actuate the arm 64 of the micro switch 63. The micro switch 63 is connected in series with motor starters and in this manner when the brake is applied, the circuit to the motor is automatically opened. This circuit will hereinafter be more fully described.

Turing now to FIGS. 6 and 7, there is illustrated my air control valve generally shown at 7 0. The valve comprises a rectangular body 71 having a central passageway 72 in which the spool or plunger 73 is mounted for vertical reciprocation. The valve has an inlet 74, an outlet 75 leading to the blind end of cylinder 14, and

the frame 19 as seen in FIGS. 1 and 3. that this valving structure is generally similar to that disclosed in my Patent No. 2,757,642, which issued an outlet 76 leading to the rod end of cylinder 14. Cu 'either side of the inlet 74 are two exhaust outlets 77 and 78 which are connected through small tubes 79 to the front end of the motor. In this manner the exhaust from the valve will pass inwardly through the end bell 7, through the elongated housing 3 cooling the stator 4 and rotor 5, and passing outwardly through the opening 80 between the housing 9 and the coupling 10. Through this arrangement the motor can substantially be cooled by as much as 15-20 F.

The feed valve is operated by means of a solenoid 81 which is mounted on the top thereof and is directly con- =nected to the plunger 73. The plunger is also connected to the housing 71 on the-valve member by means of tension springs 82 and 83 secured to a transverse pin 84 pivotally mounted on an extension of the plunger 73 and to pins 85 and 86 mounted on the housing wall. Horizontally pivotally mounted within the housing 71 is a latch member 87 which is designed to engage within a slot 88 in the spool or plunger 73. This latch is in engagement with a compression spring 89 which is adapted pivotally to force the latch within the slot 88. Mounted on the wall of the housing 71 is a micro switch 90 having an actuating plunger 91 adapted to be actuated by the latch arm 87 when it is recessed within the slot 88 of the spool or plunger 73. This micro switch 90 is connected in series with a solenoid which operates an air valve supplying the brake actuating air cylinder 60, which will hereinafter be more fully described. The latch arm, of course, will be operated by a suitable stop rod 93 which will release the latch from the slot 88. The exact position of the stroke at which the rod will be actuated can be controlled by an adjustable stop 94 threaded in It is here noted August 7, 1956.

Referring now to FIG. 8, here is shown the schematic wiring diagram for the sequential operation of my machine. The drive motor 2 is supplied with a suitable source of three wire alternating current, generally shown at 100, there being a suitable disconnect switch 101 in the supply lines. The motor herein illustrated is shown as a two speed motor utilizing multiple windings. It will, of course, be understood that more than two speeds may be employed if desired. For example, the three wires .102 may lead to the low speed windings and the three wires 103 may lead to the high speed windings. In the wires 102 there is a suitable across-the-line starting switch, generally indicated at 104, operated by relay 105. Similarly in the lines 103 another across-the-line starter 106 may be actuated by relay 107. The relays 105 and 107 are connected in parallel and each are connected in series with a speed selector switch 108. Current for these relays is supplied through a suitable step-down transformer 109 connected to two wires of the main source of supply 100. It can now be seen that the switch 108 will energize either relay 105 or 107, but not both. The relays 105 and 107, as well as the switch 108, are connected directly in series with the micro switch 63 which is actuated by the brake. The solenoid 81, which actuates the main air valve 70, is connected in series with a suitable starting switch 110. The micro switch 90 which is actuated by movement of the latch 87 resulting from the actuation of valve 70 energizes solenoid 111 which actuates air valve 112 to supply air to the blind end of cylinder 60 to release the brake. An ammeter 113 is connected to the motor supply lines whereby the load of the motor may be readily observed. In this manner when there is no load or work engaging the cutting tool, the idling load of the motor may be readily observed and the nut 38 may be adjusted to control the pressure of the bearing members 37 against the shaft 6. In this manner the proper bearing pressure can always be maintained by an observance of the change in load on the motor 2 by means of the ammeter 113.

Operation Assuming the spindle to be in its maximum out-feed position, after closing disconnect switch 101, the operator actuates the start button 110 which energizes solenoid 81 which raises the spool or plunger 73 to allow the latch 87 to snap within the slot 88 as the result of the pressure of spring 89. The latch 87 then closes the microswitch energizing the solenoid 1 11 actuating the brake air valve 112. This permits air to flow under pressure into the cylinder 60 from a suitable source of air pressure which forces the wedge 54 between the flanges of the brake bands releasing the brake and closing normally open micro switch 63. This automatically energizes motor 2 at whichever speed the selector switch 108 dictates. As a result of the movement of plunger or spool 73, the air is passed through the valve 70 from the inlet 74 to the feed outlet 75. In this manner the piston moves the entire spindle, rotor 5 included, toward the work. The pressure on the piston 13 of the cylinder 14 is controlled through a pressure control switch schematically illustrated at 114 in FIG. 3. In this manner the pressure within the cylinder 14 may be regulated to control the pressure of the tool against the work. This pressure control switch may have an adjustable pressure range of for example from 5 to 150 psi. with a 5.5 p.s.i. difi'erential. When the tool approaches the end of its stroke, the adjustable stop 23 will abut against the push rod 26 forcing hydraulic fluid from the end of the cylinder 28 through the adjustable needle valve to slow the in-feed of the work as it approaches its breakout point. As soon as the cutting tool has finished the particular operation, the adjustable stop 94 will engage the stop rod '93 which will release the latch 87 permitting the springs 82 to return the plunger or spool to a position where the air will be supplied from inlet 74 to outlet 76 supplying air to the rod end of the cylinder 14 to move the tool away from the work. The movement of latch 87 opens micro switch 90 simultaneously with the reversing of the flow of air which retracts the spindle. The opening of micro switch 90 open circuits the solenoid 1111 which permits movement of the valve 112 to its original position exhausting the air in brake cylinder 60 allowing the spring 62 to pull the wedge 54 from between the flanges 49 and 50. This simultaneously clamps the brake bands 46 and 47 around the enlarged part 45 of the shaft 6 and opens micro switch 63 to deenergize selectively, depending upon the position of switch 108, relay or 107 to open circuit the motor 2. As a result of this the spindle rotation is stopped at the forward position of the stroke and is returned dead. As soon as the spindle reaches its start position, the cycle may be repeated simply by pressing the starting button again. It is noted that the brake Will remain on and the motor stopped until the start switch is again actuated.

As a result of the elongated rotor 5, the torque produced by the motor 2 at the extreme in-feed position will be much greater than it would have been if the stator and rotor were of the same dimensions.

It will now be seen that I have provided a compact boring unit or the like which incorporates the added features of a powerful motor 2 employing a more uniform torque throughout the stroke of the tool, an adjustable bearing whereby the load of the motor may be accurately controlled, a simple and expedient braking mechanism to retract the tool from the work in a stationary condition, and means to sequentially automatically operate the various parts of my tool throughout a complete cycle of operation.

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 any of the following claims, or the equivalent of such, be employed.

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

1. In combination an electric drive motor having a stator and a rotor supported therein for rotation about its central axis and for axial movement',.a drive'shaft driven by said rotor and movable axially therewith. and; having means thereon for mounting a rotary cuttingrtoolfor infeed andoutfeed movement relative. to a...workpiece,. and actuating means operative axially to. reciprocate said rotor thus correspondingly axially to reciprocate saiddrive shaft, said rotor being substantially longer than said stator whereby a substantially uniform motor: speed for. all axial infeed positions of said rotor will be obtained.

2. The combination. of claim. 1 including means to stop rotation of said drive shaft during suchoiutfeed movement only.

3. The combination of claim 1 including brake. means to restrain rotation of said driveshaft during such outfeed movement only.

4. The combination of claim. 1 including means. responsive to the reversal of movementfrom infeed to outfeed to stop rotation of said drive shaft.

5 The combination set forth in claim lincluding means to adjust the stroke length of such infeed andoutfeed movement.

6. The combination set forth in claim 1 including means to vary the idling load on said drivemotor.

7. A rotary tool comprising an electric drive motor having a stator and a rotor supported therein" for rotation about its central axis and for axial. movement, a drive shaft driven by said rotor and axially movable therewith, means operative axially to reciprocate said. rotor thus axially to reciprocate said drive shaft, said roto-r'being substantially longer than said stator toreduce the solenoid elfectof said rotor within said stator and to maintain a substantially uniform motor speed for all axial positions of'said rotor.

8. A rotary tool as set forth in claim 7 wherein said rotor is sufficiently longer than said stator always'to occupy substantially the entire axial interior of said stator during axial reciprocation.

9. A rotary tool comprising an. electric drive motor having a stator and a rotor supportedtherein for rotation about its central axis for axial movement, a drive shaft driven by said rotor and axially movable therewith, means operative to reciprocate said rotor through a predetermined stroke thus axially toreciprocate. said drive shaft, said rotor being at least the length of said predetermined stroke longer than said stator.

10. A rotary tool as set forth in claim 9 wherein said rotor is sufliciently longer than said stator always to occupy substantially the interior of said stator during said predetermined stroke.

11. A rotary tool comprising an electric drive motor having a stator and a rotor supported therein for rotation about its central axis and. for axial movement, a drive shaft driven by said rotor and axially movable therewith, means operative axially to reciprocate said rotor thus axially to reciprocate said drive shaft, and means to deenergize said drive motor in one axial direction of movement only.

12.. A rotary'tool comprising an electric drive motor having a stator and a rotor supported thereinfor rotation about its central axis and for axial movement, a drive shaft driven by said rotor and axially movable therewith, means operative axially to reciprocate said rotor. thus axially to reciprocate said drive shaft for an infeed and outfeed stroke, and means to stop rotation of said. drive shaft during such outfeed stroke.

13. A rotary tool as set forth in claim 12 wherein said means to stop rotation of said drive shaft comprises a brake means operative thereon actuated during such outfeed stroke.

14. A rotary tool as set forth in claim 13 wherein said rotor is substantially longer than said stator.

15. A rotary tool as set forth in claim 14 wherein said means operative axially to reciprocate said rotor is an air operated piston and cylinder, the exhaust of which is directed through said stator.

16. A rotary tool as set forth in claim 15 wherein said brake means is operated by a second piston and cylinder which simultaneously actuates a switch to deenergize said motor when the brake is applied.

17. A rotary tool as set forth in claim 16 wherein'said second piston and cylinder is a single acting air operated piston in which the pressure is released on such outfeed stroke of the tool.

18. A rotary tool as set forth in claim 17 including a main bearing for the drive shaft thereof and means to adjust the pressure of said bearing upon the shaft, said motor including means to measure the load thereon.

1-9. A rotary tool as set forth in claim 12 including means to slow the axial movement ofsaid shaft as it ap proaches the end of its infeed stroke.

20. In combination an electric drive motor having a stator and a rotor supported therein for rotation about its central axis and for axial movement, a drive shaft driven by said rotor and movable axially therewith and having means thereon mounting a rotary cutting tool for infeed and outfeed movement relative to a workpiece, and actuating mean-s operative axially to reciprocate said rotor thus correspondingly axially to reciprocate said drive shaft, said rotor being substantially longer than said stator, brake bands surrounding said drive shaft, movablewedge means to force said brake bands away from said shaft, spring means operative to clamp said bands against said shaft on removal of said wedge means, means operative by said wedge means to deenergize said motor when said wedge means is removed, and means responsive to-said actuating means to move said wedge means.

References Cited in the file of this patent UNITED STATES PATENTS 2,504,853 Locke et al. Apr. 18, 1950 2,648,238 Raney Aug..11, 1953 2,902,891 Wollenhaupt -l Sept. 8', 1959 FOREIGN PATENTS 27,506 Great Britain 19.03

213,897 Australia Feb.. 13,. 1958

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