US3797583A

US3797583A - Positive feeding structure for tools incorporating pressure controlled feed member

Info

Publication number: US3797583A
Application number: US00309147A
Authority: US
Inventors: R Quackenbush
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-10-31
Filing date: 1972-11-24
Publication date: 1974-03-19
Anticipated expiration: 1991-03-19
Also published as: US3583822A

Abstract

A feed member telescopes and is threadably engaged with a rotatably driven spindle arranged for moving the spindle axially in a feed stroke upon the feed member rotating faster than the spindle and in a retraction stroke upon the feed member remaining stationary. The feed member is also arranged axially movable along the spindle a limited distance between first and second positions controlled for remaining stationary in the first position and rotating faster then the spindle to, at and from the second position. A fluid actuated piston reacts against the feed member controlled to urge the feed member axially toward and normally retain the same in the second position at the commencement and during the spindle feed stroke, the feed member causing the spindle feed stroke upon reaching the second positon and causing the retraction stroke upon the return to the first position so that when the spindle in the feed stroke meets resistance against spindle axial movement overcoming the action of the fluid piston, the feed member returns from second to first position for start of the retraction stroke.

Description

United States Patent [191 Quackenbush POSITIVE FEEDING STRUCTURE FOR TOOLS INCORPORATING PRESSURE CONTROLLED FEED MEMBER- [75] Inventor: Robert C. Quackenbush, Glendale,

Calif.

[73] Assignee: Arthur B. Quackenbush, Glendale, Calif. a part interest 22 Filed: Nov. 24, 1972 21 Appl. No.: 309,147

Germany 173/145 Primary Examiner'--Ernest R.- Purser Attorney, Agenl. 0r Firm-Mahoney, Schick &-Cislo Mar. 19, i974 [57] ABSTRACT A feed member telescopes and is threadably engaged with a rotatably driven spindle arranged for moving the spindle axially in a feed stroke upon the feed member rotating faster than the spindle and in a retraction stroke upon the feed member remaining stationary. The feed member is also arranged axially movable along the spindle a limited distance between first and second positions controlled for remaining stationary in the first position and rotating faster then the spindle to, at and from the second position. A fluid actuated piston reacts against the feed member controlled to urge the feed member axially toward and normally retain the same in the second position at the commencement andduring the spindle feed stroke, the feed member causing the spindle feed stroke upon reaching the second positon and causing the retraction stroke upon the return to the first position so that when the spindle in the feed stroke meets resistance against spindle axial movement overcoming the action of the fluid piston, the feed member returns from sec- 0nd to first position for start of the retraction stroke.

I2 Claims, 7 Drawing Figures QHIIIIIQI;

minnows mm 13797583 SHEET 3 UF 3 Fig. 7.

POSITIVE FEEDING STRUCTURE FOR TOOLS INCORPORATING PRESSURE CONTROLLED FEED MEMBER BACKGROUND OF THE INVENTION This invention relates to a positive feeding structure for tools which incorporates a pressure controlled feed member and more particularly, to such a structure having a feed member threadably engaged with the peripheral threads of spindle and axially movable a limited distance as determined by applied fluid pressure for accomplishing the feed and retraction control of the spindle. Furthermore, in the preferred form of the present invention, the combination of the fluid pressure reacting against the feedmember and the fluid flow may be effectively used for controlling the rotation of the feed member to thereby control the action of the feed memberon the spindle and the spindle axial movement in the feed and retraction strokes. These and other features of the positive feeding structure of the'present invention will be discussed and described in the following specification and claims.

In my prior US. Pat. No. 3,411,593 entitled Tool Incorporating Positive Feeding Structure, there is described and claimed a tool having a rotatably driven spindle controlled in feed and retraction strokes by a feed member threadably engaged with peripheral threads formed on the spindle. The feed member is retained axially stationary and is rotated faster than the spindle rotation to produce axial threaded movement of the spindle relative thereto producing the spindle feed stroke. At completion of the feed stroke, rotation of the feed member is discontinued and the feed member retained rotatably stationary with the continued rotation of the spindle reversely axially threadably moving the spindle relative to the feed member to accomplish the retraction stroke.

Unless selectively manually carried out by an operator, the shifting of the tool from the feed to the retraction strokes is carried out by a pivotal lever engaged by a preset control collar on the spindle. As the spindle reaches the end of the feed stroke, the control collar engages the pivotal lever shifting the same to a position actuating certain fluid valves whichaffects the drive to the feed member to stop the feed member and retain it stationary thereby commencing the. spindle retraction stroke. Thus, unless earlier terminated by manual operator action, the tool, once the spindle feed stroke is started, will always carry out a complete predetermined feed stroke before commencing the spindle retraction stroke.

Proper control of the tool, therefore, obviously requires strict operator attention. It is true that no problems will be presented provided the spindle can always move completely through its feed stroke and then return in its retraction stroke, but if the particular cutting or forming device mounted on and driven by the spindle meets an unpredicted obstruction intermediate the spindle feed stroke, only quick operator action in manual control can immediately terminate the spindle feed stroke and begin spindle movement in its retraction stroke. If the operator does not so act, damage to a workpiece being worked upon, the cutting or forming device on the spindle, or even the spindle and other portions of the tool may be severely damaged.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide a positive feeding. structure forv tools which incorporates a pressure controlled feed member wherein the feed member, despite feed member threaded engagement with the spindle periphery, is axially movable between a first position in which it is controlled to carry out the spindle retraction stroke and a second position in which it is controlled to carry out the spindle feed stroke with the feed member being retained in its second position by fluid pressure. Thus, upon the spindle in its axially moving feed stroke meeting an axial restraning pressure greater than the fluid pressure maintaining the feed member in its second position, the greater restraining pressure will cause the feed member to move from its second back to its first position for being controlled to commence the restraction stroke. The restraining pressure on the spindle overcoming the fluid pressure and ultimately causing commencement of the retraction stroke may be that created by a sufficient obstruction opposing spindle feed stroke movement or may be a preset stop member located to always determine the predetermined extent of the spindle feed stroke.

It is a further object of this invention to provide a positive feeding structure for tools which incorporates a pressure controlled feed member and including the foregoing elements and operating in the foregoing general manner wherein the flow of fluid, preferably liquid such as hydraulic fluid or oil, which provides the fluid pressure controlling the feed member movement may be used to automatically control the feed member and spindle actuations, thereby automatically switching the spindle from feed stroke movement to retraction stroke movement upon the restraining pressure overcoming the fluid pressure as the result of the spindle either meeting an obstruction or completing its predetermined feed stroke. In the preferred form, the fluid pressure is directed against the feed member at the desired commencement of the spindle feed stroke and while the feed member is in the first position, and the same control member controlling such fluid pressure direction controls the feed member rotation to start the feeding member rotation faster than the spindle rotation. This causes the rotating spindle to remain axially stationary while the fluid pressure forces the feed member to move threadably along thespindle to the feed member second position followed by commencement of the spindle axial movement in the feed stroke when the feed member reaches its second position. When the spindle reaches the end of its feed stroke as caused by either an obstruction or a preset stop member preventing further spindle feed stroke movement, the restraining forces on the spindle exceed the fluid pressure retaining the feed member in its second position so that the feed member must move threadably along the spindle back to its first position forcing reverse flow of the fluid creating the fluid pressure and with such reverse fluid flow reactivating the actuating means to stop the feed member to start the spindle retraction stroke.

These and other objects of the invention will become apparent as the description proceeds herein when taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. I is a side elevational view of an embodiment of tool incorporating the principles of the present invention, the tool being shown with the spindle thereof in retracted position ready for the initiation of a spindle feed stroke;

FIG. 2 is a top plan view looking in the direction of the arrows 22 in FIG. 1;

FIG. 3 is an enlarged, fragmentary, vertical sectional view looking in the direction of the arrows 3-3 in FIG.

FIG. 4 is an enlarged, fragmentary, vertical sectional view looking in the direction of the arrows 4-4 in FIG. 2, but with the tool controls shifted and the various tool elements shifted commencing the spindle feed stroke;

FIG. 5 is a fragmentary, horizontal sectional view looking in the direction of the arrows 5-5 in FIG. 4;

FIG. 6 is a view similar to FIG. 4, but with the tool controls shifted and the various tool elements shifted commencing the spindle retraction stroke; and

FIG. 7 is a fragmentary horizontal sectional view looking in the direction of the arrows 7-7 in FIG. 6.

DESCRIPTION OF THE BEST EMBODIMENT CONTEMPLATED:

Referring to the drawings, the positive feeding structure incorporating the pressure controlled feed member of the present invention is shown forming a part of a right angle drive tool of the general type for rotatably driving working members such as drills through feed and retraction strokes in the carrying out of a drilling operation. Furthermore, the principles of the present invention constitute an improvement of the structure described and claimed in my prior US. Pat. No. 3,4l 1,593 entitled Tool Incorporating Feeding Structure with the tool described herein having many common elements and mechanisms to the tool described in said prior patent.

As shown, the tool includes a housing generally indicated at 10 mounting main drive means preferably in the form of an air driven drive motor 12 of generally usual form connected through a somewhat usual gear train generally indicated at 14 to a secondary spindle drive gear 16. The secondary spindle drive gear 16 is in turn, drivingly connected to a primary spindle drive gear 18 telescoping and spline connected to a peripherally threaded spindle 20. The spindle 20 is mounted in the housing 10 axially movable in feed and retraction strokes rotatably carrying a working end 22 to and from a workpiece in somewhat usual manner and with the primary spindle drive gear 18 spline connected thereto, rotatable drive of the spindle is maintained at all times while the primary and secondary

spindle drive gears

16 and 18 remain axially stationary.

A spindle feed member or feed gear 24 is also telescoped over the spindle 20 spaced above the primary spindle drive gear 18 but is threadably engaged with the peripherally threaded spindle and is also axially movable withinthe housing a limited axial distance between an upper first position shown in FIG. 6 and a lower second position shown in FIG. 4. Rotation of the feed member or gear 24 is controlled by a feed member drive gear 26 spline connected thereto and likewise mounted within the housing 10 for limited axial movement as well as rotation in certain axial positions. Thus, the feed gear 24 and the feed member drive gear 26 remain at all times rotatably connected while being axially movable independent of each other their respective limited axial distances.

As can be seen in FIGS. 4 and 6, the feed member drive gear 26 has a lower axle portion 28 projecting downwardly into a sleeve bearing 30 and an upper axle portion 32 projecting upwardly into a needle bearing 34. The lower axle portion 28 is positioned for engagement by a piston 36 of a retraction stroke air cylinder 38 and the upper axle portion 32 is positioned for engagement by a piston 40 of a feed stroke air cylinder 42 through a ball 44. Also, a series of control pins 46 project through and from the feed member drive gear 26 for engagement in appropriate openings 48 of the secondary spindle drive gear 16 when the feed member drive gear is in its lower position as shown in FIG. 4 and for engagement in appropriate openings 50 in the housing 10 formed partially by a gear stop 52 when the feed member drive gear is in its upper position as shown in FIG. 6. Therefore, when the feed member drive gear 26 is in its lower position engaged with the secondary spindle drive gear 16, it is rotatable with the secondary spindle drive gear and in turn, rotates the feed member 24, but when the feed member drive gear 26 is in its upper position engaged with the housing 10, the feed member drive gear is retained stationary retaining the feed member stationary. It is important to note, however, that the ratios between the secondary and primary

spindle drive gears

16 and 18 and between the feed member drive gear and

feed member

26 and 24 are different such that the rotatable speed of the spindle 20 is less than the rotatable speed of the feed member 24 when the feed member is rotated. Obviously, the rotational speed of the feed member 24 is reduced below the speed of the spindle 20 when the feed member'drive gear 26 is engaged with the housing. 10 since the feed member is then stationary while the spindle continues it constant rotation.

A fluid cylinder 54, preferably actuated by a liquid such as hydraulic fluid or oil, is formed in the housing directly above the feed member 24 and likewise telescoping the spindle 20, although spaced slightly outwardly therefrom in the housing. The fluid cylinder 54 includes an annular lower abutment member 56 downwardly actionable against the feed member 24, an annular piston 58 downwardly engaging the abutment member and an annular seal 60 downwardly abutting the piston. Upwardly of the seal 60, as best seen in FIGS. 5 and 7, the fluid cylinder 54 is connected through a passage 62 to a two-part fluid chamber 64, one part of which is closed by a threadably adjustable filler plug 66 and the other part of which is movably closed by an axially extending plunger 68 forming a part of a piston 70 of a feed actuating cylinder 72.

Within feed actuating'cylinder 72 and axially opposite the plunger 68, a control rod 74 projects axially from the piston 70 through a guide block 76 forming the opposite end closure of the feed actuating cylinder. As can be seen in FIG. 7, when the piston 70 is positioned fully at the control rod end of the feed actuating cylinder 72, the control rod 74 projects through the guide block 76 and a determined distance therefrom engageable with an end 78 of a pivotal hand control lever 80. An opposite end 82 of the hand control lever is similarly engageable with a control rod 84 of a shuttle valve 86, the control rod 84 and shuttle valve 86. normally being axially urged toward the hand control lever 80 by a spring 88.

The shuttle valve 86 is connected to an air supply and when in the right hand position as shown in FIG. 5 supplies air to the right hand or control rod side of the piston 70 within the feed actuating cylinder 72, as well as through a line 90 to the feed stroke air cylinder 42 against the piston 40 thereof. When the shuttle valve 86 is in the left hand position as shown in FIG. 7, air to the feed actuating cylinder 72 and feed stroke air cylinder 42 is cut off while air is directed in a line 92 to the retraction stroke air cylinder 38 against the piston 36 thereof. For purposes to be hereinafter more clearly explained during a description of the operation of the tool, it will be noted that the preferred liquid in the fluid cylinder 54 and fluid chamber 64 is isolated from the air in the feed actuating cylinder 72, appropriate seals being employed as shown for this purpose. Also, as shown in FIG. 3, the hand control lever 80 is releasably retained in its maximum clockwise pivoted position as shown in FIG. 7 by a detent 94 of usual form engageable therewith.

Finally, a feed stroke limiting collar 96 is telescoped over the upper end of the spindle 20 adjustably secured to the spindle at the desired location for limiting the extension of the spindle from the housing 10 in its feed stroke and determining the location of the start of the retraction stroke. When the spindle has extended a maximum in its feed stroke as preset by the collar 96, the collar downwardly engages against an abutment member 98 on the housing 10 as shown in FIGS. 4 and 6. This, of course, creates a restraining force .on the spindle 20 preventing further feed stroke axial movement as will be hereinafter described in detail.

In operation of the embodiment of the tool shown and described herein, and starting with the spindle 20 fully retracted and the various elements in retraction stroke positioning as they would be at termination of the retraction strokes, such elements are initially in the positions shown in FIGS. 6 and 7. In such positions, the

feed member 24 is in its upper position and the feed member drive gear 26 is in its upper position locked stationary with the gear stop 52 and housing 10. Also, the piston 70 of the feed actuating cylinder 72 is in its right hand position, the hand control lever 80 is pivoted fully clockwise retaining the shuttle valve 86 in its left hand position, and the main drive motor 12 is not actuated.

To start the spindle feed stroke, air is directed to the main drive motor 12 beginning constant rotation of the spindle 20 through the gear train 14, secondary spindle drive gear 16 and primary spindle drive gear 18. Also, the hand control lever 80 is pivoted counterclockwise forcing release of the detent 94 and with such hand control lever movement forcing the control rod 74 to the left, in turn, forcing the piston 70 and plunger 68, all of the feed actuating cylinder 72 to the left. Still further, this counterclockwise pivoting of the hand control lever 80 releases the control rod 84 of the shuttle valve 86 permitting the spring 88 to move the shuttle valve to its right hand position directing air to the feed actuating cylinder 72 and the feed stroke air cylinder 42 while cutting off air to the retraction stroke air cylinder 38, as shown in FIG. 5.

Referring to both FIGS. 4 and 5, air to the feed stroke air cylinder 42 causes the piston 40 thereof to move the feed member drive gear 26 downwardly from its stationary locked engagement with the housing 10 to engagement with and rotation by the secondary spindle drive gear I6 causing rotation of the feed member 24 faster than the spindle 20 and in the same direction. Pressurized air into the feed actuating cylinder 72 creates a pressure against the piston tending to move the same to the left creating an air pressure to the left against the plunger 68 and such pressure reacts against the liquid'within the fluid chamber 64 and fluid cylinder 54 so as to ultimately react against the piston 58 urging the feed member 24 downwardly from the position shown in FIG. 6 to the position shown in FIG. 4. With the feed member 24 rotating faster than the spindle 20 and the downward force against the feed member by the fluid cylinder 54, the spindle initially remains axially stationary and the feed member threads downwardly along the spindle from the position shown in FIG. 6 to the position shown in FIG. 4 and upon reaching this lower position, the feed member becomes axially stationary and the spindle begins to feed downwardly in its feed stroke.

Thus, the various elements retain the positioning shown in FIGS. 4 and 5 with the fluid cylinder 54 continuing to exert a downward pressure against the feed member 24 throughout the feed stroke of the spindle 20. It will be noted that such pressure by the fluid cylinder 54 is maintained as a result of the piston 70 of the feed actuating cylinder 72 having progressively moved to the left as the feed member 24 moved downwardly and as caused by the air through the shuttle valve 86 and into the feed actuating cylinder. Therefore, as long as the feed member 24 can be retained in this lower position as shown in FIG. 4 by the fluid cylinder 54, the feed stroke of the spindle 20 will be continued, so that the extent of the spindle feed stroke will be determined by when the spindle meets an axially restraining force sufficient to overcome the downward force of the fluid cylinder 54 against the feed member 24 as created by an obstruction of some form prior to engagement of the feed stroke limiting collar 96 with the housing 10 or the engagement of this collar with the housing, in either case the reaction being the same.

In either case, when a sufficient axial restraining force is exerted against and in opposition to the feed stroke of the spindle 20, the spindle can no longer move axially in its feed stroke direction or downwardly as shown in FIG. 4 so that the feed member 24 begins to thread upwardly along the spindle and against the pressure of the fluid cylinder 54. This upward threading of the feed member 24 along the spindle 20 from the position shown in FIG. 4 back to the position shown in FIG. 6 causes the liquid within the fluid cylinder and the fluid chamber 64 to react against the piston 70 in the feed actuating cylinder 72 through the plunger 68. This compresses the air within the feed actuating cylinder 72 by movement of the piston 70 thereof to the right from the position shown in FIG. 5 to the position shown in FIG. 7, causing the control rod 74 to project through the guide block 76 and engage the end 78 of the hand control lever 80 shifting this hand control lever clockwise back to the position shown in FIG. 7.

The repositioning of the hand control lever 80 clockwise causes the lever end 82 to force the control rod 84 of the shuttle valve 86 to the left repositioning the shuttle valve to the left as shown in FIG. 7. This cuts off 'air to the feed actuating cylinder 72 and the feed stroke air cylinder 42 while directing air to the retraction stroke air cylinder 38 against the piston 36 thereof. The retracting stroke air cylinder 38, therefore, forces the feed member drive gear 26 upwardly from engagement with the secondary spindle drive gear 16 and ultimately upwardly into stationary engagement with the gear stop 52 and the housing 10 ceasing rotation of the feed member 24 and retaining the same stationary.

Thus, when the spindle 20 in the feed stroke meets the axial restraining pressure either from the feed stroke limiting collar 96 or otherwise, the spindle dwells in axial movement, that is, remains in a dwell position axially stationary, until the feed member 24 has threaded axially upwardly from its lower position shown in FIG. 4 to its upper position shown in FIG. 6, and then through the reduction of the rotational speed of the feed member drive gear 26 and feed member below the rotational speed of the spindle, in this case rotationally stationary, the spindle 20 begins upward movement in its retraction stroke. Furthermore, the spindle 20 continues in its retraction stroke upward movement and the various elements'are retained in the positions shown in FIG. 6 for the determined retraction stroke. Upon completion thereof, air to the drive motor 12 is cut off and the cycle is complete with a new cycle being started in the exact same manner as hereinabove described.

As was hereinbefore pointed out, in the operation of the tool for a complete cycle of spindle feed and retraction strokes, at the beginning of the feed stroke, it is necessary for the feed member 24 to thread downwardly along the constantly rotating spindle 20 from the feed member upper position shown in FIG. 6 to the feed member lower position shown in 'FIG. 4 which feed member threading and repositioning takes place while the spindle is axially stationary. Also, at the end of the feed stroke and prior to commencement of the retraction stroke, the spindle 20 is being restrained axially stationary while the feed member 24 threads upwardly therealong from the position shown in FIG. 4 to the position shown in FIG. 6. Thus, during these two periods of time when the feed member 24 is moving axially, the spindle 20 is in dwell positions as far as axial movement thereof is concerned and these dwell positions in period of time are determined by the amount of movement of the piston 70 within the feed actuating cylinder 72 required to move the feed member 24 as well as control the shuttle valve 86.

Since the fluid within the fluid cylinder 54 is a liquid and virtually incompressible for a closed and properly sealed system, the volume thereof remains constant and the movement of the piston 70 of the feed actuating cylinder 72 is, in effect, determined by the overall volume of the fluid cylinder 54 and the fluid chamber 64, again assuming a constant volume of liquid. Thus, with the filler plug 66 selectively adjustable inwardly and outwardly as shown in FIGS. 5 and 7, by adjusting the filler plug inwardly to reduce the overall volume of the fluid cylinder 54 and fluid chamber 64, the feed member 24 from its lower position shown in FIG. 4 is permitted to move upwardly to its upper position a lesser amount, in other words, the distance between these two positions is less and the dwell periods are, therefore, necessarily less, and an outward adjustment of the filler plug 66 will create the opposite reaction lengthening the spindle dwell periods. This, therefore, provides limited spindle dwell period adjustment.

With the tool structure hereinbefore described and shown in the accompanying drawings, a positive feeding structure for tools is provided wherein the spindle 20 is automatically shifted from feed stroke movement to retraction stroke movement upon the spindle meeting a restraining force against feed stroke axial movement sufficient to overcome a predetermined force of the fluid cylinder 54. Thus, the tool is automatically shifted from the feed to the retraction stroke when the feed stroke limiting collar 96 engages the housing 10 according to a predetermined setting of the collar, but equally important, if the spindle engages an unexpected obstruction, the spindle feed stroke will be terminated and the retraction stroke commenced automatically without damage to the elements of the tool or the workpiece upon which working operations are being performed. Furthermore, this automatic regulation of the tool operation may be accomplished directly through the necessary flow ofliquid within the fluid cylinder 54 and the fluid chamber 64 providing such advantageous control in a structure of maximum simplicity,-yet positive operation.

I claim:

. 1. In a tool incorporating a positive feeding structure of the type having a housing mounting a peripherially threaded spindle rotatable and axially movable in feed and retraction strokes, spindle drive means for rotating said spindle while permitting said axial movement in said feed and retraction strokes, a rotatable feed member threadably engaged with said spindle peripheral threads, feed control means shiftable for rotating said feed member at a faster speed than said spindle to axially move said spindle in said feed stroke when said feed member is axially stationary and for reducing said feed member speed below said spindle to axially move said spindle in said retraction stroke when said feed member is axially stationary; the improvements comprising: means mounting said feed member on said housing movable axially between a first and second position; fluid means operably connected with said feed member actionable for exerting a predetermined pressure axially against said feed member urging said feed member toward said second position; feed actuating means operably associated with said feed control means and said fluid means, said feed actuating means shifting said feed control means to rotate said feed member at said faster speed and actuating said fluid means to exert said predetermined pressure when said feed member is in said first position initially causing axial threaded movement of said feed member along said spindle from said first to said second position and then axial spindle movement in said feed stroke, said feed actuating means shifting said feed control means to rotate said feed member at said reduced speed and ceasing actuation of said fluid means upon return of said feed member back to said first position from said second position caused by said spindle in said feed stroke receiving an axial restraining pressure greater than and opposing said fluid means predetermined pressure followed initially by threaded movement of said feed member along said spindle from said second to said first position and then axial spindle movement in said retraction stroke.

2. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle axially movable along said spindle between said first and second positions; and in which said fluid means includes an annular piston telescoped over said spindle positioned reacting axially against said feed member.

3. A tool incorporating a positive feeding structure as defined in claim 1 in which said fluid means includes piston means on said housing spaced from said spindle for maintaining fluid pressure against said feed member during movement of said feed member between said first and second positions and in said second position; and in which said feed actuating means includes valve means for controlling said piston means of said fluid means.

4. A tool incorporating a positive feeding structure as defined in claim 1 in which said fluid means includes piston means on said housing spaced from said spindle for maintaining fluid pressure against said feed member during movement of said feed member between said first and second positions and in said second position; and in which said feed actuating means includes valve means for controlling said piston means of said fluid means, hand control means operably associated with said valve means for controlling positioning of said valve means.

5. A tool incorporating a positive feeding structure as defined in claim 1 in which a selectively adjustable restraining means is operatively associated with said spindle for restraining movement of said spindle at a determined end of said feed stroke to provide said axially restraining pressure greater than the opposing said fluid means predetermined pressure.

6. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle movable axially along said spindle between. said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operatively associated with said feed member for exerting said predetermined pressure axially against said feed member, secondary piston means spaced from said primary piston means for directing fluid under pressure to said primary piston means; and in which said feed actuating means includes valve means operably associated with said secondary piston means of said fluid means for controlling movement of said secondary piston means.

7. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle movable axially along said spindle between said first and second positions; in which said'fluid means includes an annular primary piston means telescoped over said spindle and operably associated with said feed member for exerting said predetermined pressure axially against said feed member, secondary piston means operably connected to said primary piston means for supplying liquid under pressure to said primary piston means; and in which said feed actuating means includes valve means operably associated with said secondary piston means of said fluid means and said feed control means, said valve means controlling air against said secondary piston means of said fluid means and controlling air to said feed control means for shifting said feed control means.

8. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle axially movable along said spindle between said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operably associated with said feed member for exerting said predetermined pressure axially against said feed member, secondary'piston means spaced from said primary piston means for directing fluid under pressure to said primary piston means; and in which said feed actuating means includes valve means operably associated with said secondary piston means of said fluid means for controlling movement of said secondary piston means, and control means operably associated with said valve means for controlling positioning of said valve means.

9. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle movable axially along said spindle between said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operably associated with said feed member for exerting said predetermined pressure axially against said leed member, secondary piston means operably connected to said primary piston means for supplying liquid under pressure to said primary piston means; and in which said feed actuating means includes valve means operably associated with said secondary piston means of said fluid means and said feed control means, said valve means controlling air against said secondary piston means of said fluid means and controlling air to said feed control means for shifting said feed control means, and control means operably associated with said valve means for controlling positioning of said valve means.

10. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle movable axially along said spindle between said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operably associated with said feed member for exerting said predetermined pressure axially against said feed member, secondary piston means operably connected to said primary piston means for supplying liquid under pressure to said primary piston means; in which said feed actuating means includes valve means operably associated with said secondary piston means of said fluid means and said feed control means, said valve means controlling air against said secondary piston means of said fluid means and controlling air to said feed control means for shifting said feed control means, and control means operably associated with said valve means for controlling positioning of said valve means; and in which a selectively adjustable restraining means is operably associated with said spindle for restraining movement of said spindle at a determined end of said feed stroke to provide said axially restraining pressure greater than and opposing said fluid means predetermined pressure.

M. A tool incorporating a positive feeding structure as defined in claim 1 in which adjustment means is operably associated with certain of said feed member, said fluid means and said feed actuating means for selectively varying distance axially of said spindle between said feed member first and second positions.

12. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle movable axially along said spindle between said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operably associated with said feed member for exerting said predetermined pressure axially against said feed member, secondary piston means operably connected to said primary piston means for supplying liquid under pressure to said primary piston means; in which said feed actuating means includes valve means operably associated with said secondary piston means of said valve means and said feed control means, said valve means controlling air against said secondary piston means of said fluid means and controlling air to said feed control second positions.

Claims

1. In a tool incorporating a positive feeding structure of the type having a housing mounting a peripherially threaded spindle rotatable and axially movable in feed and retraction strokes, spindle drive means for rotating said spindle while permitting said axial movement in said feed and retraction strokes, a rotatable feed member threadably engaged with said spindle peripheral threads, feed control means shiftable for rotating said feed member at a faster speed than said spindle to axially move said spindle in said feed stroke when said feed member is axially stationary and for reducing said feed member speed below said spindle to axially move said spindle in said retraction stroke when said feed member is axially stationary; the improvements comprising: means mounting said feed member on said housing movable axially between a first and second position; fluid means operably connected with said feed member actionable for exerting a predetermined pressure axially against said feed member urging said feed member toward said second position; feed actuating means operably associated with said feed control means and said fluid means, said feed actuating means shifting said feed control means to rotate said feed member at said faster speed anD actuating said fluid means to exert said predetermined pressure when said feed member is in said first position initially causing axial threaded movement of said feed member along said spindle from said first to said second position and then axial spindle movement in said feed stroke, said feed actuating means shifting said feed control means to rotate said feed member at said reduced speed and ceasing actuation of said fluid means upon return of said feed member back to said first position from said second position caused by said spindle in said feed stroke receiving an axial restraining pressure greater than and opposing said fluid means predetermined pressure followed initially by threaded movement of said feed member along said spindle from said second to said first position and then axial spindle movement in said retraction stroke.

6. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle movable axially along said spindle between said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operatively associated with said feed member for exerting said predetermined pressure axially against said feed member, secondary piston means spaced from said primary piston means for directing fluid under pressure to said primary piston means; and in which said feed actuating means includes valve means operably associated with said secondary piston means of said fluid means for controlling movement of said secondary piston means.

7. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle movable axially along said spindle between said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operably associated with said feed member for exerting said predetermined pressure axially against said feed member, secondary piston means operably connected to said primary piston means for supplying liquid under pressure to said primary piston means; and in which said feed actuating means includes valve means operably associated with said secondary piston means of said fluid means and said feed control means, said vaLve means controlling air against said secondary piston means of said fluid means and controlling air to said feed control means for shifting said feed control means.

8. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle axially movable along said spindle between said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operably associated with said feed member for exerting said predetermined pressure axially against said feed member, secondary piston means spaced from said primary piston means for directing fluid under pressure to said primary piston means; and in which said feed actuating means includes valve means operably associated with said secondary piston means of said fluid means for controlling movement of said secondary piston means, and control means operably associated with said valve means for controlling positioning of said valve means.

9. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle movable axially along said spindle between said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operably associated with said feed member for exerting said predetermined pressure axially against said feed member, secondary piston means operably connected to said primary piston means for supplying liquid under pressure to said primary piston means; and in which said feed actuating means includes valve means operably associated with said secondary piston means of said fluid means and said feed control means, said valve means controlling air against said secondary piston means of said fluid means and controlling air to said feed control means for shifting said feed control means, and control means operably associated with said valve means for controlling positioning of said valve means.

11. A tool incorporating a positive feeding structure as defined in claim 1 in which adjustment means is operably associated with certain of said feed member, said fluid means and said feed actuating means for selectively varying distance axially of said spindle between said feed member first and second positions.

12. A tool incorporating a positive feeding structure as defined in claim 1 in which said feed member is telescoped over said spindle movable axially along said spindle between said first and second positions; in which said fluid means includes an annular primary piston means telescoped over said spindle and operably associated with said feed member for exerting said predetermined pressure axiaLly against said feed member, secondary piston means operably connected to said primary piston means for supplying liquid under pressure to said primary piston means; in which said feed actuating means includes valve means operably associated with said secondary piston means of said valve means and said feed control means, said valve means controlling air against said secondary piston means of said fluid means and controlling air to said feed control means for shifting said feed control means, and control means operably associated with said valve means for controlling positioning of said valve means; and in which adjustment means is operably associated with said fluid means for selectively varying an internal volume of said fluid means between said primary and secondary piston means to consequently vary distance axially of said spindle between said feed member first and second positions.