US2294447A - Chucking mechanism - Google Patents

Description

Sept. 1, 1942. l L. o. cARLsEN cHucKING MEcHANIsM Filed sept. e, 1941 2 Sheets-Sheet 1 Znvcnfor NN Q n NQ LEON/IRD 0. CHRLSEN Patented Sept. 1, 1942 CHUCKING MECHANISM Leonard O. Carlsen, Rochester, N. Y., assignor to Gleason Works, Rochester, N. Y., a corporation of New York Application September 6, 1941, Serial No. 409,859

4 Claims.

The present invention relates to chucking mechanisms and particularly to chucking mechanisms for use on gear generating machines.

In gear generating machines, the teeth of a gear are cut by producing a relative rolling movement between the cutting tool and the work while the tool is taking its cut. In the machines commonly employed the rolling motion is effected by rotating the work spindle on its axis in time with the rotation or translation of a cradle or carrier on which either the tool or the work spindle is mounted.

In machines of the type described, it is com-I mon practice to employ a draw-bar actuated chucking mechanism. The draw bar is mounted in a bore in the work spindle, and chucking is effected by moving the draw-bar rearwardly in the work spindle, while dechucking is effected by moving the draw-bar forwardly. Heretofore it has been the general practice to move the draw'- bar into chucking position and to hold it there by spring pressure. Usually a coil spring is provided that operates against one side of a piston that is secured to the draw bar. For moving the draw bar to released position, fluid pressure may be applied to the opposite side of the piston. To conduct the motive iiuid to the piston, and yet permit the work spindle to rotate freely for generation, a swivel connection is usually employed. The swivel member may be mounted on the cylinder, which houses the chuck-operating piston, or on a reduced diameter extension of this cylinder.

For gears of different dimensions, the draw-bar must be moved different distances to eiTect chucking and for different type gears, different lengths of draw-bar should be employed. With chucking mechanisms heretofore used, the chuck-actuating parts had to be partially or wholly disassembled to adjust the length of movement of the draw bar or to substitute one draw bar for another. Spring actuated chucking mechanisms moreover have certain disadvantages. Springs have to be of considerable size to secure adequate chucking pressures, and it is impractical to vary the amount of such pressures for dilerent jobs.

A primary object of the present invention is to provide a chucking mechanism for machines of the type described which, while of simple construction, will be wholly fluid-pressure operated, that is, a chucking mechanism in which both chucking and dechucking may be eiectuated by fluid pressure.

A further object of the invention is to provide a simple type of chucking mechanism for machines of the character described which may be operated wholly by pneumatic pressure.

Another object of the invention is to provide a draw-bar type of chucking mechanism in which the draw-bar may be adjusted or removed from either end of the workA spindle of the machine on which the chucking mechanism is employed.

Still another object of the invention is to provide a fluid-pressure actuated chucking mechanism in which the swivel connection for conducting the motive fluid to the chuck may be so mounted as to keep the rotary friction at a minimum.

Another object of the invention is to provide a chucking mechanism in which not only the friction but the weight of the parts may be held to a minimum so as to permit of employing the chucking mechanism on even the smallest sizes of gear generating machines.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

A preferred embodiment of the invention is yillustrated in the accompanying drawings, in

which:

Fig. 1 is a fragmentary plan view of a gear generating machine of known construction provided with a chucking mechanism built according to one embodiment of the present invention,

parts being shown in section;

Fig. 2 is a sectional view on an enlarged scale through the chuck-actuating mechanism and through associated p-arts of the machine;

Fig. 3 is a section on the line 3-3 of Fig 2; and

Fig. 4 is a section on the line 4 4 of Fig. 2.

In the chucking mechanism illustrated in the drawings the draw-bar is connected to a piston that is mounted to reciprocate in a cylinder which is secured to the work spindle of the gear cutting machine. The draw bar extends through a bore in the work spindle and through an aligned bore in the piston, and the draw bar is adjustably connected to the piston at the rear end thereof. Thus the draw-bar may be adjusted axially relative to the piston for varying the effective length of the draw bar and may readily be removed from the machine through the rear end of the piston or through thefront end of the work spindle. Compressed air is preferably employed for operating the piston to move the draw-bar to and from chucking position. The air is conducted to opposite sides of the piston through a swivel member, that is journaled directly on a stem portion or extension of the piston, and through ducts formed in the stem portion of the piston itself.

By mounting the swivel member directly on the stern of the piston, the diameter of the part which is to turn in the swivel can be kept quite small land hence the amount of turning friction is kept at a minimum during rotation of the Work spindle. By drilling the ducts, which conduct the motive fluid from the swivel member to opposite sides of the piston, in the stem of the pisto-n instead of providing these ducts in the walls of the cylinder, as has been the case with previous forms of fluid-operated chucks, the size of the cylinder walls is kept down and the size and weight of the cylinder accordingly reduced. The use of pneumatic pressure for operating the chuck eliminates some of the valving required in a hydraulically operated chuckingY mechanism, and, in conjunction with the reduction in friction and saving in weight achieved through other features of the improved chucking mechanism, makes it possible tov employ the new chucking mechanism on even the smallest size of geai` generating machine. Minimum friction losses and weight are always of prime consideration in the structure and cost of such machines.

In the drawings,vthe invention'is shown in use on a straight bevel gear generating machine of known typ-esuch asis disclosed, for instance, in the patent to Gleason et al., No. 1,660,502, of Februar'y' 28, 1928, or in the patent to Hill et al., No. 1,816,376 of July 28, 1931, but it will be understood that this is for the purpose of illustration only and is in order` thattheconstructio'n, and operation and obj ect of the new chucking mechanis'm may more readily be described, and that the new chucking mechanism is not in any way to be considered as limited to use on the'type of machine shown. A

The bevel gear generating machine illustrated has a bed or base l'on which is slidably mounted a tool head I I which carries apai'r of reciprocating tools, one of which'isY seen at I2 in the drawings. The frame I`is` provided at one end vvith an upright I3 which is Vformed with ways I4. "e

These ways serve as guides for a cradle or carrier' I5 whichisoscillatably mounted upon the upright |73' and which isheld on the ways I4 by the arcuate gib I6. Mounted on the cradleI5 is v a work head or support' I8, andy jour'n'aledv in suitable bearings in this work head I8' is the sleeve I9. Withinthe sleeve I9 is journaledthe work spindle 20 'of the machine. The work spindle has a tapered bore at' its forward end tovreceive the work arbor 2|. The gear G, which is to be cut', is securedto the arbor, and the arbor is secured to the work spindle by a draw bar 23 anda nut or horseshoe washer 22. The drawbar passes through aligned bores in the arbor and spindle.

The work head I3'is mounted onthe cradle I5 for angular adjustment to position the gear to be cut in accordance with its root angle, and it is secured to the cradle I5, after adjustment, vby the bolts 24 which engage in the arcuate slots 25 formed in the upper face of the cradle. Keyed to the sleeve I3 is an arm 26 which carries a bevel gear segment 2l. This segment meshes with a relatively stationary bevel or crown gear segment 28 which is mountedv on the base or bed I0 of the machine.

Durin'g'cut'tingV of a tooth of the gear G, the tools are reciprocated back and forth across the face of the gear blankwhile the blank is rolled relative to the tools. Therolling motion is' ef- 75 fected by oscillation of the cradle I5 on its axis. As the cradle oscillates back and forth, the segment 26 rolls back and forth on the segment 28, thereby transmitting an oscillatory motion t0 the sleeve I9. During cutting, the sleeve I9 is connected to the work spindle 20 through the indexing mechanism of the machine so that the oscillatory motion of the sleeve I9 may be transmitted to theV work, thereby producing the generating motion required for production of proper tooth profiles on the gear blank. When a tooth of the gear has been completed, the tools are Withdrawn from engagement with the gear blank and the work spindle is indexed.

The indexing mechanism may be of any suitable cons'truction. That shown is of the same type as described in the Hill et al. patent above mentioned; Keyed or otherwise secured to the work spindle 20 is a ratchet wheel 30. Mounted on the hub of this ratchet Wheel is a notched index plate 31. Integral with the sleeve vI9 is an arm' 32 which carries a lock lever 33. This lever carries a dog (not shown), which engages a notch of the indexl plate 3l' to lock the work spindle to the sleeve during cutting. The index mechanism is enclosed within a' guard or housing 35 which is xedly secured to the work head I8. Suitably mounted by means of apin 35 on the guard or housing 36'is` a pawl 31`which is adapted to be trippedperiodically to engage the ratchet wheel Sil, to hold` the work spindle 20 against rotation with the sleeve I9 during indexing as described int the Hillet al. patent. This serves to hold the workv spindle 20' stationary while the sleeve'l!) continues'to rotate under actuation of` the segment' 2`I'and thus the work spindle is indexed relative'to the sleevel The gear cutting machine itself' andits indexing mechanism' form` no part.' however, of the present invention. They have been described simply that the application of the present invention may more readily' beund'erstood. The construction and operation of my` improved chucking mechanism will nowbe described.

Mounted' on the hub ofA the ratchet' wheel`30 is an adaptor member 4I).V This adaptor member is secured to the ratchet wheel 30hy' screws 4I which also serve to'fasten'the index' plate`3l to the' ratchet wheel. The end plate 42 of a cylinder 4'3'is"sec'ured to the adaptorl byscr'ews 44. The end plate 42 is' fastened to the cylinder 43'v by screws 452 A piston 41 is' mounted Vinthe cylinder 43 to reciprocate therein.

There'is a hollowstem or piston rod 48th-raded intothe piston 4T centrally `thereof. The piston rodi or stem. 48'projectsl both'thr'ogh the endp'late 42'0'f the Cylinder il13"and'tlrolll'gh the rear' end wall 4of thiseyl'inder. The forwardly projecting vporti'ono'f' the piston rod is1 of reduced diameter and slidesin a tubular guide' member 49 which is mounted Yin'a'ceritral openingin the end plate 42. The rearwardly projecting portion of the piston rod 48' is oflarg'er diameter and passesvthr'ough a centrally dispolledv opening in the rear end'wau of thecyiinderfs: It 'is'gided by a guard Ell'which issec'ured'by sc'rew's'5I` to the rear' end' plate of the cyliriderv 43. Y

suitable packipgs 52 and 53g respectively are provided to preventleakage'of the motive` fluid from either end oftnegcynnder; siiitauiepackings 5 4 and 55 are providedin mepiston" 41'1 to prevent leakage between opposite sidesI of' the piston.

The rear end of the piston rod' 48 is'Iiioijnted in" aswivei member sa that 'forms' part of die' means for conducting the motive fluid to the cylinder 43. The swivel member carries a packing box 6| of suitable construction which serves to seal the connection between the swivel member and the stem portion 48 against leakage of the motive fluid. The stem portion 48 is free to rotate in the swivel member, but the swivel member and packing box are secured against longitudinal movement relative to the stem 48 by a lock member 63 which is secured to the stem by a set screw 64. w

The draw bar 23 extends through the arbor 2|, a tube 66, which is keyed to the work spindle 29, and through the whole of the stem portion 48 of the piston 41. It threads at its rear end into the rear end of the stem portion 48. Thus, as a1- ready mentioned, the piston rod may be adjusted axially in the work spindle. Thus, also, as already mentioned, it may be removed from either the front end or the rear end of the work spindle. To remove it from the rear end of the work spindle, the washer 22 will, of course, have to be rst removed. A lock nut 65, that threads on the rear end of the draw-bar, serves to secure the draw-bar in any adjusted position in the spindle.

The motive fluid is supplied to the cylinder 43 from any suitable source through a manually operated valve 19 (Fig. l) which may be of any suitable construction and which may be mounted at any suitable point on the machine. The valve is connected to the swivel member 68 by flexible hose 1| and 12. The hose 1| connects with a duct 13 in the swivel member 68. This duct communicates with a peripheral groove 14 (Figs. 2 and) in the packing box 6|. The groove 14 communicates through radial ducts 15 in the packing box 6| with a circular groove 16 which is formed in the internal bearing surface of the packing box. The groove 16 is in communication with two ducts 11, that are spaced 90 apart and that are drilled in the stem 48. These two ducts lead to the rear face of the piston 41,

The hose 12 connects with a duct 88 (Figs. 2 and 4) in the swivel member 68. This duct communicates with a circular groove 8| formed in the periphery of the packing member 6|. The groove 8| communicates through two ducts 82 in the packing member with a circular groove 83 formed in the inside bearing surface of the packing member. The groove83 communicates with the two ducts 84 that extend longitudinally through the stem 48 and are spaced 90 apart. These two ducts lead to the front face of the piston 41.

The peripheral grooves 14 and 8| and the internal grooves 16 and 83 insure balanced pressure around the peripheries of the packing box 6| and stem 48, respectively, thus preventing canting of the swivel member 69 on the stem and permitting the stem 48 to rotate readily in the swivel.

Theswivel member 68 is held against rotation with reference to the work head |8 by an arm 95 which is secured at one end to the index housing 36 and which at its other end fits into a longitudinal slot 96 formed in the swivel member. The slot 9S is of sufcient length to permit the swivel member to move forward and back with the piston stem 48 in the movement of the piston 41.

The operation of my improved mechanism will be understood from the preceding description, but may briefly be summed up here. To chuck a gear and hold it in chucking position, the operating lever 69 (Fig. 1) of the reversing valve 10 is moved to put the line 12 on supply and the line 1| on exhaust. The pressure fluid then passes through the duct 88, groove 8|, ducts 82, groove 83 and ducts 84 to the front side of the piston 41, causing the piston to be moved rearwardly in the cylinder 43 to thereby move the draw bar 23 rearwardly and clamp the gear blank to be cut. During this rearward movement of the piston 41, the motive fluid will exhaust from the rear end of the cylinder 43 through the duct 11, groove 16, ducts 15, groove14, duct 13 and hose 1|.

To release the chuck, the control valve 18 is reversed to put the line 1| on supply and the line 12 on exhaust. The motive fluid then flows through the ducts 13, groove 14, ducts 15, groove 16, and ducts 11 to the rear face of the piston 41, and exhausts from the front face of the piston through the ducts 84, groove 83, ducts 82, groove 8|, du-ct 88, and hose 12. YThis forces the pistonforward in the cylinder 43 to carry the draw bar 23 forward in .the work spindle.

In any pneumatically operated system, water is apt to condense and become entrapped in the system, thus preventing its most eflicient functioning. To get rid of any such entrapped water, two ducts 99 and 9| are provided in the cylinder 43. These ducts are normally closed by ball check valves 92 and 93, respectively. When either ball check valve is open, the corresponding duct 99 or 9| communicates with a duct 94, which in turn communicates through a duct 95 directly with the open air. The water can be forced out of the system by opening the valves 92 and 93 and operating the reversing valve 19 to move the piston 41 back and forth t0 force the water out through the ducts 98 and 9|, 94 and 95.

The chuck mechanism described can be operated hydraulically if desired. In this case it functions exactly in the mann-er already described except for the motive fluid used. In any hydraulically operated system, air is apt to become entrapped. The check valves 92 and 93 and ducts 98 and 9| and 94 and 95 serve to permit getting rid of the entrapped air in the same Way as entrapped water may be forced out of the pneumatically operated system By mounting the swivel member directly on the stem 48, the amount of surface exposed to turning friction during generation can be kept at a minimum as already stated. As already stated also, by putting the ducts 11 and 84 that lead to opposite sides of the piston 41 in the stem portion 48 of the piston instead of in the walls of the cylinder 43, the size and therefore the weight of the cylinder 43 caribe kept at a minimum. Both these features enable the chucking mechanism of the present invention to be used practically even on the smallest size of gear cutting machine. y

While the invention has been described in connection with a machine of the segment roll type for generating gears, it will be understood that it may Abe used on any type of gear generating machine and in fact on various other types of machines. The present application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thusV described my invention, what I claim is:

1. The combination With a rotary Work spindle of a chucking mechanism comprising a draw bar Which is mounted in a bore in the spindle and Which is reciprocable therethrough, a cylinder which is secured to said Spindle, a piston operatively connected to the draw bar and reciprocable in said cylinder, said lpiston having a stem portion which projects through one end of the cylinder, means for conducting fluid under pressure to opposite sides of the piston including a relatively fixed swivel member which is journaled on the stem portion of said piston and which has ducts. formed therein that communicate with ducts that are formed in the stem portion o1" said piston and that lead to opposite sides of the piston.

2. The combination With a Werk support and a work spindle journaled therein, of a chucking mechanism comprising a cylinder secured to the Work spindle, a piston reciprocable in the cylinder and having a stem portion projecting through one end of the cylinder, said Work spindle and piston stem having aligned bores extending therethrough, and a draw bar mounted in said bores and having a threaded connection at its rear end to the rear end of the piston stem, and said-piston stem having ducts formed therein for conducting a pressure fluid to opposite side faces of the piston, respectively.

3. The combination With a Work support and a work spindle journaled therein, of a chucking mechanism comprising a cylinder secured to the Work spindle, a piston reciprocable in the cylinder and having a stem portion which projects through one end of the cylinder, a draW bar Which is mounted in aligned bores in the Work spindle andthe piston stem and which is adjusta-bly connected at its rear end to the rear end of the Ypiston stem, av swivel member mounted directly on the piston stem and secured to the Work support against rotation withvthe work spindle, and means for conducting pressure fluid to said swivel member, said swivel member having ducts formed therein to connect said means With ducts formed in said piston stem, and the latter ducts leading to opposite sides, respectively, of the piston.

4. The combination with a Work support and a rotary Work spindle journaled therein, of a chucking mechanism comprising a cylinder which is secured to the Work spindle, a piston reciprocable in the cylinder and having a stem portion Which projects through one'end of the cylinder, a draw bar which is mounted in aligned bores in the Work spindle and the piston stem and Which is adjustably connected at its rear end to the rear end of the piston stem, a swivel member journaled on the piston stem and secured to the work support against rotation with the Work spindle, and means for conducting pressure fluid to opposite sides of the piston comprising a pair of ducts formed in the piston stem, a pair of grooves formed in the internal bearing surface of the swivel member and communicating, respectively, with said ducts, and means for supplying the pressure fluid to said grooves.

LEONARD O. CARLSEN.

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