US3762231A - Variable diameter pulley - Google Patents

Abstract

A variable diameter pulley hydraulically shiftable to a selected effective diameter, the pulley including stop means for determining its maximum and minimum effective diameters.

Description

United States Patent 1 Pettigrew I VARIABLE DIAMETER PULLEY [75] Inventor: David D. Pettigrew, Gibsonia, Pa.

[73] Assignee: Rockwell International Corporation,

Pittsburgh, Pa.

22 Filed: Feb. 22, 1972 21 Appl. No.: 228,064

Related U.S. Application Data [62] Division of Ser. No. 27,786, April 13, 1970.

[52] U.S. Cl. 74/230.l7 F [51] Int. Cl. e F16h 9/00 [58] Field of Search 74/230.l7 F

[56] References Cited UNITED STATES PATENTS 2,868,027 1/1959 Oberholtz et al. 74/230.17 FT Oct. 2, 1973 2,198,940 4/1940 Heyer et al 74/230.17 F 3,014,378 12/1961 Bruet 74/230.l7 F 3,618,413 11/1971 Cherpes 74/230.17 F

FOREIGN PATENTS OR APPLICATIONS 91,549 8/1961 Denmark 74/230.17 F

Primary ExaminerC. J. Husar Attorney-Strauch, Nolan, Neale, Nies & Kurz [57] ABSTRACT A variable diameter pulley hydraulically shiftable to a selected effective diameter, the pulley including stop means for determining its maximum and minimum effective diameters;

2 Claims, 2 Drawing Figures 89 lOO PATENTEDBBT 2 I973 SHEET 2 BF 2 FIG. 2

VARIABLE DIAMETER PULLEY This is a division, of application Ser. No. 27,786 filed AP 13, 1970.

BACKGROUND OF THE INVENTION The invention described in original application Ser. No. 27,786, now US. Pat. No. 3,702,740, relates generally to drilling machines and more particularly to a novel, improved, coolant or oil-hole drilling machine capable of drilling accurate, true holes in a wide variety of metals at the maximum determinable cutting and penetration rates for the metal workpiece with acceptable tool life not heretofore attainable with conventional solid tool drilling machines and/or known oilhole drilling machines.

The concept and process of oil-hole drilling has been known for about forty years, but has generally been confined to automatic screw machine and turret lathes and used primarily in speciality applications for drilling deep holes, e.g., up to about 20 diameters in depth. The limited usage and acceptance of the process for more conventional high production shop applications has been attributed to the high cost of oil-hole drills which generally were considered custom items, the unavailability of suitable oil-hole drilling machines, and the resulting attitude that relatively few advantages were gained from its usage. Available oil-hole drilling machines used in the past were either specially-built custom machines or mere adaptations of conventional solid too], dry drilling machines modified to pump coolant through the drill.

In more recent years, industry has awakened to the potential of the oil-hole drilling process and its application to more conventional, high production drilling op-.

erations. It was pointed out at an American Society of Tool and Manufacturing Engineers Conference held in April, 1967, that a solid tool drill press built years ago, e.g., in 1918, if it had adequate speed and power, would probably drill a hole as fast as any modern solid tool drill press, due largely to the fact that there has been no major change in the condition existing at that point where the metal is cut by the solid drill. When a drill enters the metal, it is completely enclosed on all sides but one, and that one is partially blocked by escaping chips. This then creates ideal conditions for overheating and wearing or breaking a cutting edge. Consequently, the speed of the drill and rate at which it is fed into the metal is very much limited by these existing conditions.

On the other hand, oil-hole drills direct a high pressure coolant through holes in the flutes of the oil-hole drill from the shank end down to the cutting end of the drill, with the coolant serving not only to cool the drill point but also to wash the chips upwardly out of the hole.

The conferees noted that recent advances in and availability of oil-hole drill equipment and associated coolant pumping equipment such as that illustrated in US. Pat. No. 3,342,086 have increased penetration rates of oil-hole drills substantially over penetration rates of conventional solid drills. While such an increase was considered impressive, it was generally agreed that in order to obtain the maximum benefit and savings from oil-hole drilling, new commercially available oil-hole drilling machines would have to be built, since existing machines simply did not have the rigidity, variable speed and feed capacities, and/or effective coolant system necessary to provide the maximum determinable cutting and penetration rates for metal workpieces with acceptable tool life desirable for production operations. It was pointed out that this inadequacy of conventional machines has been emphasized by the development of the carbide-tipped drill, since there is no commercial standard machine capable of utilizing the carbide-tipped drill to its fullest advantage in any but the smallest drill sizes.

At the conference, it was recognized'that the most prevalent type of oil-hole drill press such as that illustrated by US. Pat. No. 2,977,827 was merely a modification of a conventional drill press with an attachment type inductor gland attached to the lower end of the spindle and receiving the shank end of the oil-hole drill. Coolant is fed into the inductor and thence through the passageways of the drill down to the cutting edge. However, it was concluded that this type of machine would not be acceptable for general application, since experirnents showed that the length of the extension of the drill point from the drill spindle and spindle bearing had an appreciable effect on drill life which was improved by minimizing the total extension of the drill from the spindle. Thus, in a machine employing an inductor gland, the gland adds to this total extension and thereby decreases tool life. It was generally concluded that the shortest total extension will be obtained by feeding coolant directly through the spindle rather than an external attachment type inductor.

In addition, it was also agreed that no conventional available drill press could be readily converted since none possesses the stiffness, horsepower, variable feed and speed requirements necessary for a versatile, general purpose, oil-hole drill press.

SUMMARY OF THE INVENTION The object of this invention resides in the provision of a novel variable diameter pulley included in a novel variable speed drive assembly capable of rotating a drill spindle within an infinitely variable speed range, e.g., rpm to 10,000 rpm. The drive assembly includes a relatively high horsepower motor driving avariable diameter pulley arrangement which is connected to the drill spindle through an intermediate gear assembly which may be shifted to one of three possible speed ranges. Thus, a desired spindle speed may be selected by setting the gear assembly within one of the speed ranges and then adjusting the diameter of the pulleys to select a specific speed within the set range.

Other objects and advantages will become more apparent from reading the following detailed description of the invention with reference to the accompanying drawings in which like numerals indicate like parts and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, partially sectioned side elevation view of the variable speed spindle drive system drivingly connected to the upper spindle of the two piece spindle structure mounted on the head of the drill press described in original application Ser. No. 27,786;

FIG. 2 is a fragmentary side elevation section view of the primary hydraulically operated, variable diameter pulley which is part of the drive system shown in FIG. 1, the right and left sides of FIG. 2 showing the pulley in its maximum and minimum diameter positions, respectively;

DETAILED DESCRIPTION OF THE INVENTION As shown in FIGS. 1, the spindle structure for rotating and vertically moving a drill is a two-piece structure including a hollow upper spindle 48 rotatably mounted in housing 46 and a lower spindle 50, the upper end 51 of which is vertically reciprocable within upper spindle 48 and rotatable therewith through a spline connection 51a.

THE VARIABLE SPEED DRIVE SYSTEM AND SPINDLE STRUCTURE Referring to the drawings, the drive assembly 52 for rotating upper spindle 48 includes a motor 54 mounted on a support platform 56, the corner legs 58 of which are fixed to the top of housing 46. A hydraulically operated, variable diameter pulley 60 (FIG. 2) includes a first inner conical disc 64 having a hub 66 slidably mounted on motor shaft 62 by a spline connection and a second outer conical disc 68 having a hub 70 slidable on hub 66 and rotatable therewith. The lower end of hub 66 is closed by an end plate 72 which engages the inner race of alower roller bearing 74.

A lower non-rotative sleeve member 76 has a lower annular face against which the outer race of bearing 74 seats and spaced outer and inner cylindrical sleeve sections 78 and 80 which form an annular recess 82 therebetween. The inner surface of section 80 is spaced from hub 70. An upper non-rotative sleeve member 84 has an annular face against which the outer race of upper roller bearing 86 seats, the inner race of which seats against outer disc hub 70. Member 84 has a cylindrical sleeve section 88 which closely fits and slides within annular recess 82. O-ring 90 provides a seal between the sliding surfaces of sleeve sections 78 and 88 and O-ring 92 provides a seal between the sliding surfaces of sleeve sections 80 and 88.

A fitting 94 is provided on sleeve member 76 and has a fluid passageway 96 communicating with the base 83 of recess 82. A rigid pipe section 98 threads into fitting 94 and is movable vertically within a slot 100 of a guide bracket 102 fixed to the platform 56. Pipe 98 is connected via flexible tube 99 to a suit able fluid source. The effective diameter of pulley 60 is adjusted by introducing into or withdrawing fluid from recess 82 which acts between base 83 and end face 89 of sleeve section 88 to move cones 64 and 68 relative to each other. The minimum effective diameter of the pulley is set by an adjusting screw 104 which threads through the flange 79 of sleeve section 78 and abuts against flange 85 of sleeve member 84. The maximum effective diameter is established by a screw rod 106 which threads into flange 85 of sleeve member 84 and freely passes through an opening in flange 79. Rotation of sieeve members 76 and 84 is prevented by conduit 98 fixed against rotation within slot 100 and guide 102.

Pulley 60 through a belt 108 drives a second variable diameter pulley 110 which is fixed against rotation on the upper end of a jackshaft 112 mounted parallel to motor shaft 62 and upper spindle 48. Jackshaft 112 rotates within a bearing housing 114 that is supported from bracket assembly 116 fixed to the top of drill head casing 43. Puley 110 is a conventional follower type in which the relatively movable pulley cones are spring biased by a spring assembly in hub casing 118 to a maximum effective diameter position shown in full in FIG. 1.

With no fluid in recess 82 of puiley 60, the spring force in pulley 110 will position pulley 110 in its maximum diameter position and, through the tension in belt 108, pulley 60 in its minimum diameter position. As fluid is introduced into recess 82, the effective diameter of pulley 60 is increased and the diameter of pulley 110 is decreased against the spring force in hub assembly 118.

An electrical tachometer 119 mounted on bracket assembly 116 is belt connected to shaft 112 and has a readout device located on the central control panel 41 to indicate the speed at which shaft 112 is being driven.

A large diameter pulley 120 includes a disc 122 connected to a central hub 124 which is rotatable on the lower output end of shaft 112 through the roller bearing assembly 126 vertically positioned on the shaft between a threaded nut 128 and collar 130.

A smaller diameter timing pulley 132 includes a hub portion 134 which is keyed on shaft 112 against rotation but is slidable thereon to permit a limited amount of axial movement along the shaft. The upper edge of hub 134 is formed with a plurality of clutch teeth 136 which cooperate with a plurality of mating clutch teeth formed on the periphery of hub 124, the mating teeth forming a clutch 138 which couples pulleys 122 and 132 for rotation together when pulley 132 is shifted up wardly as shown in the right pulley position in FIG. 8A.

The shifting mechanism for pulley 132 includes an annular ring cam member 140 connected to the bottom of hub 134, with ring 140 having radially extending flanges 143 formed with a plurality of dimples 144 at predetermined radial positions which rest on support blocks 146. Blocks 146 also have dimples 148 at selected radial positions so that, when ring 140 is rotated through a predetermined angular distance from the position shown in the left hand section of FIG. 1 in which dimples 144 rest on the upper surface of blocks 146 to a position shown at the righthand section of FIG. 1 in which lower dimples 144 ride up on dimples 148, pul ley 132 will be raised to engage clutch 138 and thereby cause pulley 120 to be rotated with pulley 132 and shaft 112. A pair of retainer dogs 150 is mounted on blocks 146 to suitably guide and retain ring 140 in its selected clutch engaged or disengaged position.

The upper hollow spindle 48 is rotatably supported in housing 46 by lower high-speed bearing assembly 152. A fluid conduit fitting 153 is retained in the upper end of spindle 48 by a threaded lock nut 154 and includes an outer shaft section 155 which is rotatably supported by upper high-speed, bearing assembly 156 mounted on a bracket 158 that is fixed to the top of housing 46.

A small diameter pulley 160 and toothed clutch plate 162 are keyed on spindle 48, with pulley 160 being driven from pulley 122 by a polyflex V-belt 164, the tension of which is adjusted by an idler pulley 165 supported from bracket 158. A sleeve 166 is rotatably mounted on spindle 48 by spaced bearings 168 and 170, the inner races of which are separated by a spacer collar 172. A ring 172 is positioned between the inner race of bearing and an outer annular shoulder 176 on spindle 48. A nut 178 threads onto spindle 48 against pulley 160 and, along with shoulder 176, retains the elements in operative position.

A larger diameter timing pulley 180 is driven from pulley 132 by a timing belt 181 and includes a hub 182 which is splined on the upper portions of sleeve 166 so as to be axially slidable on the sleeve but rotatable on spindle 48. Hub 182 is formed with a plurality of clutch teeth 184 which engages clutch plate 162 when pulley 180 is shifted axially, with teeth 184 and plate 162 forming a clutch 185 by which a drive connection may be established between pulley 180 and spindle 48.

An annular gear shifting cam plate 186 rotatably slidably engages the lower portion of hub 182 and includes a plurality of upper and lower dimples 188, the latter of which rest on the upper face of a plate 190 when clutch 185 is disengaged. Plate 190 also has a plurality of dimples 192 formed on its upper surface at predetermined angular positions so that when plate 186 is rotated to a selected position lower dimples 188 ride up on dimples 192 to raise pulley 180 and engage clutch 185. A plurality of guide and retaining ears 193 engage the upper dimples 188 and retain gear plate 186 in a set position. As shown in FIG. 1, a shift rod 194 extends between and connects plate 186 and ring 140 for rotation together. Gear plate 186 has a forward gear segment 195 which is moved by a pinion 196 fixed on the upper end of a shaft 198 which is part of a backgear assembly 204 and is rotatably mounted in gear housing 46.

Pinion 196 may be rotated to position gear plate 186 and ring 140 in one of three possible set positions, each representing a specific speed range. The gear plate 186 and ring 140 are so designed that clutches 138 and 185 cannot be both engaged at the same time, i.e., the angular position of dimples 144 of plate 140 is different than that of dimples 188 on gear plate 186 so that pulleys 132 and 180 cannot be raised together.

As is evident from the description thus far, in one set position representing the high speed range, clutch 138 will be engaged and clutch 185 disengaged and spindle 48 is driven from shaft 112 through pulley 132, clutch 138, pulley 120, belt 164, and pulley 160. Pulley 180 and sleeve 166 will simply freely rotate on the spindle.

In a second set position representing an intermediate speed range, only clutch 185 will be engaged and spindle 48 is driven from shaft 112 through pulley 132, timing belt 181, pulley 180, and clutch plate 162. Pulley 120 will be freely rotating on shaft 112.

In a third set position representing a low speed range, neither clutch 138 nor clutch 185 will be engaged and a low speed drive for spindle 48 is established through a first smaller spur gear 200 formed on the lower end of sleeve 166, a second larger spur gear 202 keyed on spindle 48, and a back gear assembly 204 by which gears 200 and 202 are drivingly connected. Gear assembly 204 includes the shaft 198, an eccentric hub portion 206 formed on the shaft, and upper and lower gears 208 and 210 which are keyed on a sleeve 212 that is rotatably mounted on hub 206.

The lower end of shaft 198 extends below housing 46 and may be rotated by a suitable hand lever 198a which has a pin 198b that fits in suitable recesses in housing 46 to lock shaft 198 and pinion 196 in a set position. To operate spindle 48 within the low speed range, the back gear assembly 204 will be positioned as shown in FIG. 8A with gear 208 engaging gear 200 and gear 210 engaging gear 202. Both clutches 138 and 185 will be disengaged and spindle 48 will be driven from shaft 112 through pulleys 132 and 180, sleeve 166, and gears 200, 208, 210 and 202.

In a prototype drill press constructed according to the overall description set forth in original application Ser. No. 27,786, the various components of the drive system were designed so that the overall speed range was 125 to 10,500 rpm, with the low speed range being 125 to 625 rpm, the intermediate range being 550 to 2,700 rpm, and the high speed range being 2,100 to 10,500 rpm. Motor 54 was a 7 hp, 1,725 rpm, 220 volt three phase motor and variable diameter pulleys 60 and were capable of providing a speed ratio of 5:1 within each of the ranges and of varying the speed of jackshaft 112 from 600 to 3,000 rpm.

For a more complete description of the overall drive system as it is incorporated in a drill press, reference may be made to original application Ser. No. 27,786.

While the variable diameter pulley 60, which constitutes the subject matter of this application, has been described for particular utility in the drive system for a drill press, it is to be understood that the pulley has a general utility and may be used in any suitable drive system.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by letters Patent is:

l. A hydraulically operated variable diameter pulley comprising a first cone having an elongated hub adapted to be slidably mounted on a shaft, a second cone having a hub slidably mounted on said first cone hub, an axially expansible, non-rotatable sleeve assembly surrounding said hubs and including a first sleeve and a first bearing assembly connecting said first sleeve and said first cone hub for axial movement together but permitting relative rotation therebetween, said first sleeve having spaced inner and outer annular sleeve sections defining an annular recess therebetween, a second sleeve having an annular sleeve section which slidingly fits within said recess, a second bearing assembly connecting said second sleeve and said second cone hub for axial movement together but permitting relative rotation therebetween, means for conducting pressurized fluid to and from said recess to produce relative axial movement between said first and second sleeves and thereby change the effective diameter defined by said cones, and sealing means between the sliding surfaces of said sleeve sections to confine said fluid within said recess.

2. A hydraulically operated, variable diameter pulley as defined in claim 1, said sleeve assembly including means provided between said first and second sleeves for adjusting the maximum and minimum diameters formed by said cones.

t 4 i i gg g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,762,231 Dated October 2, 1973 Inventor(s) .David' D. Pettigrew It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

i- Columrl line 6 3 delete "Puley" and substitute "'Pulley' Column 4, line 31, delete "143" and substitute Signed and sealed this 27th day of August 1974.

(SEAL) Attest:

McCOY M. GIBSON, 'JR. 7 C. MARSHALL DANN Atte sting Officer Commissioner of Patents

Claims (2)

1. A hydraulically operated variable diameter pulley comprising a first cone having an elongated hub adapted to be slidably mounted on a shaft, a second cone having a hub slidably mounted on said first cone hub, an axially expansible, non-rotatable sleeve assembly surrounding said hubs and including a first sleeve and a first bearing assembly connecting said first sleeve and said first cone hub for axial movement together but permitting relative rotation tHerebetween, said first sleeve having spaced inner and outer annular sleeve sections defining an annular recess therebetween, a second sleeve having an annular sleeve section which slidingly fits within said recess, a second bearing assembly connecting said second sleeve and said second cone hub for axial movement together but permitting relative rotation therebetween, means for conducting pressurized fluid to and from said recess to produce relative axial movement between said first and second sleeves and thereby change the effective diameter defined by said cones, and sealing means between the sliding surfaces of said sleeve sections to confine said fluid within said recess.

2. A hydraulically operated, variable diameter pulley as defined in claim 1, said sleeve assembly including means provided between said first and second sleeves for adjusting the maximum and minimum diameters formed by said cones.

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