US2813445A - Driving mechanism for a screw machine - Google Patents

Description

Nqw. 19, 1957 v w. E. TWAMLEY EI'AL 2,313,445

DRIVING MECHANISM FOR A SCREW MACHINE Filed'flarch 24. 1954 6 Sheets-Sheet 1 j INVEN rows WILLIAM E. rmmer STANLEY 7. 07' A M ATTORNEK w. E. TWAMLEY EIAL 2,813, 45

muvmc uncmmsu FOR A SCREW MACHINE Nov. 19, 1957 6 Sheets-Sheet 2 Filed March 24. 1954 INVENTORS WILLIAM E. FMMLEY STANLEY 7. T

Nov. 19, 1957 w. E. TWAMLEY ETAL narvms" MECHANISM FOR A scREw' MACHINE Filed uarh' 24. 1954 6 Sheets-Sheet 3 5r M U T M N m fiw m T wk r M A m L 5V. E

N6 1T9} T957 w. E. TWAMLEY ETAL. 2,813,445

muvmc: MECHANISM FOR A SCREW MACHINE s Sheets-Sheet 5 Filed March 24. 1954 [NV N 01% WILLIAM E TWEMZEV Nov. 19, 1957 w. E. TWAMLEY ET 'AL DRIVING MECHANISM FOR A SCREW MACHINE 1954 e Sheets-Sheet' 6 Filed March 24.

INVENTORS TWAMLEV E or 77/ fi Y WILL/AM E.

STA/VL V T NEV United States Patent 2,813,445 DRIVING MECHANISM FOR A seREw MACHINE William E. Twamiey, Providence, R. L, and Stanley T. Gotham, Somerset, Mass.,assignors to Brown & Sharpe 1 m (3.0., Providence, R. 1., ascorporation of Rhode sland Application March 24, 1954,.serta1 No. 418,254 Claims. (21. sa-41 The present invention relates to an improved driving mechanism for a screw machine and is more particularly concerned with an improved organization of the driving and control devices of a screw machine having a work rotating spindle which is continuously driven at a relatively high rate of speed, and selectively in one or the other-direction, and a tool supporting and actuating assembly includinga main drive shaft which is driven always in the same direction.

It is a principal object of the invention to provide a novel construction and arrangement of the mechanism for driving and for reversing the direction of rotation of the work rotating spindle which will be positive in operation and which isiadapted to cooperate in a novel and improved manner with a similarly positive uni-directional drive ofthe tool assembly drive shaft. It is more specifically an object of the invention to provide a novel and improved means forcontrolling the drives for the work rotating spindle and the tool assembly drive shaft including an interlocking device which acts positively to :prevent inadvertent reversalof the tool assemhlydtive-shaftwith consequent interference inoperation anddamagerto the machine.

i In carryingout theinvention a reversible v electricmotor ilstproivided which is connected through :chain and sprocket gearing to drive a spindle in: a. direction which .isadirectly controlled by thedirectionofdrive Df'lth motor. The

tool support assembly drive/shaft isdriven also from the motor through chainand sprocket gearing, and through areverse gear connection which is adapted to be auto matically reversed with each reversal of the. motor so that the main drive shaft for the tool support assembly is at all times drivenin thesame direction.

. .Furtherjin accordance with the invention ran interlocking control is provided betweenthe motor direction control switchand the control elements for the reverse gear connection so that movement of either of said switches or-control element'will be accompanied automatically bya corresponding movement of the other of said elements. 1 I

With theaboverand otherobjects-in' view astmay hereinafter appear, the several features of the inventionconsist alsodn thedevices; combinations and arrangement of parts hereinafter described and claimed, which together with the advantagesrtobe obtained thereby will be readily understood .by one skilled in the art from the following description taken .inconnection with the accompanying drawings, in which:

. Fig. .1 isa fragmentary view of portionsnof screw ma chine illustrating the driving connections. .to the. main drive shaft and to the rotary .work spindle;

Fig.2 is a fragmentary view looking from the right of Fig. 1 or portions of the main driving connections for hemachineg, p

'Fig. 3 is a developed plan view of a portion of the driving connections including the reverse gearing shown in F g- Fig. 4 is a detail view lookingfromthe leftof Figs. 1

and 3 showing the relativepositions. of the severaltdri've shafts;

Fig. 5 is a wiring diagram of the electrical connections for the machine including the motor reversing switch herein described;

Fig. 6 is an elementary one line diagram of the electrical circuit shown in Fig. 5;

Figs. 7-10, inclusive,,illustrate a modified and simplified form of the screw machine driving and control, mechanism;

Fig. 7 being a view similar to Fig. 1' showing particularly a modified form of the reverse and variable speed gearing;

Fig. 8' being a fragmentary view in plan. illustrating particularly the interlocking device by means of which the direction of drive of the work spindle with relation to the driving motor is; positively related to the position of the reversing switch for the motor;

Fig. 9 being a side view of a portion of, the interlocking mechanism to illustrate particularly the motor rovers: ing switch arm; I

Fig. 10 being an end view of substantially the parts shown in Fig. 8; and

Figure 11' is a somewhat fragmentary isometric view of the interlocking connection between the. reversing switch for the motor and the pick off gears.

The invention is herein disclosed as embodied in an automatic screw machine which may be of ordinary description comprising a casing generally indicated at 20, a Work supporting spindle 22 and a tool supporting and actuating assembly including a longitudinally movable turret slide 24, a rotatable tool Supp rting turret 26 mounted on the slide, and cross Ways 28, on which .are conventionally supported front. and rear cross. slides not specifically shown. Inasmuch as details of the toolsupport assembly and the driving connections therefor are Well known in the art specific illustration therefore is believed unnecessary; It may be noted however, that the main drive for operating and for controlling theseveral elements oft-he tool supporting assembly is taken from a main drive shaft which extends along the rear side; of the machine. This shaft is specifically shown in Fig 3 and is designated at 30. C

It will be understood that the present. invention is particularly concerned with the driving and control devices. for rotating the work spindleZZ and. driving thedrive shaft 30 from which are driven. the several cooperating elements of the tool support assembly.

As best shown in Figs. 1 and 2. of the drawings the illustrated machine is driven by means of a reversible electric motor 40 which is. connected througha suitable gearing, to drive the work spindle 22 and the tool assembly drive shaft 30 shown in Fig. 3. I

The drive is taken from an armature shaft 42 of the motor to a countershaft 44' by means of.a.chain.46 [id-.- ing on sprockets 48 and '50 secured respectively tothe armature 42., and shaft and; countershaft 44. A gear 52 on shaft 44-meshes with an intermediate gear 54 which in turn meshes with a gear 56 on a second countershaft 58. The work spindle 22' of the machine is continuously driven from countershaft58 by means of a chain 69 which passes around a sprocket 62 on shaft 58 and around asprocket mounted coaxially with the work spindle 22.

The drive for the tool support, assembly is takenfrom shaft 44 through connections including. a sprocket chain 66 which rides over a sprocket 68 on countershaft 44 and over a sprocket 70 on a drive shaft 72 which carries any the end thereofa conicalfrieti'on clutch element 76 forming part of the usual start, stop and .jog clutch forthe machine. An axially shiftable clutch element 78. meting with the clutch element' /o is keyed .to turn with a driven shaft 80 mounted in alignment with the drive shaft nected through reverse gearing to drive a spline shaft 82 which is in turn connected through variable speed gearing to drive the back shaft 30 which as above pointed out is the main drive shaft from which all of the elements of the elements of the tool support assembly are driven or controlled. The reverse gearing referred to comprises a wide gear 86 secured to the driven shaft 80 and arranged to be continuously meshed with a reverse gear 88 carried on an intermediate shaft 90. A large spur gear 92 splined to and axially shiftable on the spline shaft 82 is arranged to be shifted from the intermediate neutral position shown in Fig. 3 to the left into engagement with the wide gear 86 orv to the right into engagement with a second reverse gear 94 formed integrally with reverse gear 88. The back shaft 30 is arranged to be driven from the spline shaft 82 at the alternative rates of 120 R. P. M. or 240 R. P. M., as desired, through variable speed gearing best shown in Fig. 3 which comprises a small low speed gear 96 and a larger high speed gear 98 carried on a sleeve 100 which is splined to and axially shiftable on the spline shaft 82. Movement of the sleeve 100 to the right from the intermediate neutral position shown in Fig. 3 causes gear 96 to mesh with a driven gear 102 to drive the back shaft 30 at the lower rate. Movement of the sleeve 100 to the left from the position shown in Fig. 3 alternatively will cause the larger high speed gear '98 to mesh with a gear 104 formed in tegrally with driven gear 102 to drive the back shaft 30 at the 240 R. P. M. rate.

With the illustrated construction it is proposed to reverse the direction of rotation ofthe main driving motor 40 in order to eiTect a corresponding reversal in the direction of drive of the work spindle 22. This reversal is effected by means of a reversing switch mounted on an electrical control box 108 carried on the left hand end of the machine reversing switch which consists of contacts 110, 112 and a switch 114 supported on a stationary pivot 116 to be moved into engagement with the reversing switch contacts 110, 112.

Specifically, in accordance with the present invention the operation of the switch arm 114 is linked to the means for shifting the reverse gearing through which the tool support assembly is driven as above described to insure that with each reversal in the position of switch arm 114 a corresponding reversal takes place in the position of the reverse gearing so that the direction of drive of the back shaft 30 of the tool support assembly will at all times remain unchanged. For controlling the position of the shiftable gear 92 of the reverse gearing assembly, a flange 118 on the sleeve hub of gear 92 is arranged to be engaged by a shoe 120 carried on the upper end of a gear reversing lever 122 supported to turn about a fixed pivot 124 and at its lower end connected by means of a link 126 with a downward extending tail of switch lever 114. A coupling 128 in the link 126 provides convenient means for adjusting the length of the link to insure the proper cooperation of the gear reversing lever 122 and switch lever 104.

With the arrangements shown it will be understood that when the reversing switch 114 is in an intermediate neutral position the gear reversing lever 122 and reversing gear 92 controlled thereby will occupy the corresponding intermediate neutral position illustrated in Fig. 3. When'the switch lever is turned as shown in Fig. 1 to engage the contact 112 the reverse gear 92 is moved correspondingly to the right from the position shown in Fig. 3 into engagement with reverse driving gear 94. The movement of the reversing switch 114 to the left into engagement with contact 110 causes the motor 40 to be driven in the reverse direction and simultaneously causes gear 92 to be moved to the left from the intermediate position shown in Fig. 3 into engagement with reverse driving gear 86.

The electrical control system for the machine as shown 4 particularly in Figs. 5 and 6 comprises the main driving motor 40 which is connected by a three phase line L1, L2, and L3, through a manual reversing switch 130 having contacts 110, 112 engaged alternatively by switch arm 114 as above pointed out.

As best shown in the single line electrical diagram of Fig. 6 the main starting switch is provided in the main line which comprises the switch contacts l,-11, 1,-12, and l,13. These contacts form part of a switch which is controlled by solenoid L connected into a control circuit energized by a transformer 132. The pressing of a start button 134 which acts to close start switch contact 23 energizes solenoid L which in turn operates to close the switch contacts L111, Lz-12, and L3-13, above noted. At the same time a holding switch contact 23 is closed forming a holding circuit for the main switch solenoid L. The motor 40 can be stopped by actuating a stop button 136 which opens stop switch contacts 12, so that solenoid L is deenergized causing the several switch contacts, controlled thereby, including the main line contacts I 11, 1,42, and 1 -13, to be opened. Holding switch contacts L2-3 opens. The electrical diagrams include also a disclosure of the clutch solenoid indicated at 138 in Figs. 5 and 6 which operates to control the operation of the clutch members 76, 78. As best shown in the single line diagram, Fig. 6, the clutch solenoid is controlled by a switch having a solenoid S and switch contacts $11-14, 812-15. The operation of the solenoid S is in turn controlled by means of a solenoid relay SR. Inasmuch as the portions of the electrical circuit relating to the control of the clutch solenoid form specifically no part of the present invention no further description of these electrical devices is believed necessary.

A modified form of our improved driving and control mechanism is shown in Figs. 7-10, inclusive, in which the driving connections between the motor and spindle have been replaced by two pick off gears which are of different sizes and which are adapted to be mounted in meshing relation on either of two reversely turning driving shafts to control the direction of drive of the back shaft with relation to the motor. The gears are further interchangeable with one another to vary the rate of drive of the back shaft. An interlocking device is provided between the reversing switch for the main motor and the pick oflf gear mechanism which operates operatively to prevent the mounting of the pick off gears in other than the correct position to maintain a single direction of drive of the back shaft, and also to prevent shifting of the reversing switch to a position which would be inconsistent with the set up of the pick off gears.

Referring specifically to Fig. 7 the illustration of the driving motor and the gearing in the base of the machine, together with the fragmentary showing of elements of the rotating work spindle and tool support assembly is identical with the disclosure in Fig. 1, and identical reference characters have been assigned to these parts. The connections, by means of which the back shaft 30 is driven from the driven shaft 80 in the modified form of the invention shown in Fig. 7, comprise a shaft 140 driven from the shaft 80, and a shaft 142 which is continuously driven from the shaft 140 in the reverse direction. The shafts 140 and 142, as shown particularly in Fig. 10, are both located the same distance from the driven back shaft 30. The shaft 140 is driven from shaft 80 by means of a gear 144 on the shaft 80 which meshes with a gear 146 on the shaft 140. A second gear 148 on the shaft 140 meshes with a gear 150 on the shaft 142 which is thus continuously driven in a direction reverse to that of shaft 140. The back shaft 30 is driven alternatively from the shaft 140 or from the reversely driven shaft 142 by means of two pick off gears 152, 154 which, in Fig. 10,

are shown as mounted respectively on the shaft 142 and. on the back shaft 30. It will be readily appreciated that in order to reverse the direction of drive it is necessary only to move the pick oif gear 152 from the shaft 142 onto the shaft 140. It will be further evident that a change in the drivinglrat-io between the motor and the backshaft 30 may be efiected by reversing the positions of the larger gear 152 and the small gear 154. With the gears in the positions shown in Fig. 10 the gear ratio is such that the back shaft 30 will be driven at the rate of 240 R. P. M. When the smaller gear 154 is placed on either of the drive shafts 140, 142, and the larger gear 152 is placed on the back shaft 30, the back shaft 30 will then be driven at the slower rate of' 120 R. P. M.

In accordance with the invention an interlocking device is provided which will positively insure the required correspondence between the direction of drive of the electric motor 40 and the positions of the pick of]? gears 152, 154, so that the back shaft 30; will at all times be driven in the same direction regardless of the direction of drive of the motor 40. As shown in Figs. 8-10, inclusive, the interlocking device comprises the switch arm 114, previously described which is arranged for alternative positions of the arm 114 at each side of the intermediate neutral position shown in Figs. 8, 9., and It) to close a circuit through switch contact 1 10, or through switch contact 112. The switch arm 114 in the embodiment of the invention shown in Figs. 8 to l -is connected by a link 156 with an arm 158, which is secured to a rock shaft 160, mounted to turn in a fixed bearing 162 on the machine. At its opposite end shaft .160 has pinned thereto a two- armed lever 164, 166. From an inspection of the drawings it will be appreciated that when the switch arm 114 and the lever 164, 166 are in the intermediate neutral positions shown, the pick off gear 152 may be positioned on either of the shafts 140, or 142. So long, however, as the pick oif gear 152 is mounted dn shaft 142 it will be evident that lever 164, 166 cannot, be rotated beyond the neutral position in a clockwise direction, or the switch arm 114 moved to the right to close the contact with the switch contact 110. In the alternative case that the gear 152 is supported on shaft 140 it will be evident that the lever 164, 166 could not be rotated counterclockwise or the switch arm 114 moved to the left from the neutral position shown. The motor reversing switch can therefore, be closed only in a manner to drive the motor in a direction consistent with the position of the reversing gear on shaft 140.

Figure 11 shows the interlocking connection including the switch arm 114, link 156, lever 158, rock shaft 160, and lever 164, 166 with the parts in a position in which the lower end of the switch arm 114 is shifted from its intermediate neutral position to the left so that contact 112 is engaged and closed by the upper end of the switch arm 114. Rock shaft 169 and the two- armed lever 164, 166 are rocked in a counter clockwise direction, the arm 164 being retracted, and the arm 166 being correspondingly advanced. This movement is possible because of the fact that pick off gear 152 is mounted on drive shaft 142 and not on shaft 140.

The interlocking connections above described are further utilized in accordance with the invention to permit the opening of a pivoted cover overlying the pick off gears only when the switch arm 114 is in the intermediate neutral position shown in Figs. 8, 9, and 10, and the motor 40 and pick off gears driven thereby are not running. The overlying cover 170, referred to, is pivoted at 172 on the base of the machine and is arranged to swing from the closed position shown in Fig. in which the gears are covered to the dot and dash line open position shown in Fig. 10 in which the gears are readily accessible to the operator. The cover 170 is provided with an arcuate projection 174 which is arranged to cooperate with a lug 176 mounted on the longitudinally movable arm 156 connected with the switch arm 114. The lug 176 is formed with a transverse slot 178 which for the intermediate neutral position of switch arm 114 is adapted to receive the projection 174 of the door 170, thus permitting the door to be swung freely in a counterclockwise direction to the dotted open position of Fig. 10. When, however, the switch arm 114 and associated parts are in switch engaging or motor driving position one or the other end portion of the lug 176 moves into the path of the projection 174 of the door 170, thus locking the door in its closed position. Alternatively, when the door is open and the projection 17'4' thereof is engaged in slot 178 it is evident that switch arm .114 cannot be shifted from the intermediate neutral position shown so that the motor switch cannot be shifted to. running position until after the door is closed.

The invention having been described what is claimed is:

1., In a screw machine having a hollow rotatable work spindle and associated tool supporting and actuating devices includinga drive shaft, the combination. of driving means for the machine including a reversible driving element, driving connections between the driving element and the work spindle whereby the spindle is reversibly driven with the driving element, additional reversible driving connections between the driving element and drive shaft including two reversely rotating shafts, a drivn ft, nd a pa r pick, off ge rs mo nted on said driven shaft and selectively on one of said reversely roa ing shafts n m shi g rela io contr l me n op able to reverse said driving element,v and an interlocking device including a locking element Shiftable. to block the mo nt g. o a pi k off gear alternativ y n one. or the other of said reversely rotating shafts, and connections e we ns id control m ans nd said locking element op bl t shift thelocki ng. element with each reversal of he driving elem nt.

2 In a screw machine having a hollow rotatable work pindl and associat tool supporting and actuatin vices including a drive shaft, the combination of driving means for the machine including a reversible electric motor, driving connections between the motor and the work spindle whereby the spindle is reversibly driven with the motor, additional reversible driving connections between the motor and the drive shaft which include two reversely rotating shafts, a driven shaft and a pair of pick off gears mounted on said driven shaft and selectively on either of said reversely rotating shafts in meshing relation, a reversing switch for the motor, and an interlocking device including a locking arm shiftable to block the mounting of a pick off gear alternatively on one or the other of said reversely rotating shafts, and a connection between said locking arm and said switch operable to shift said locking arm from one to the other of said positions with each shift of the switch arm from one to the other position.

3. In a screw machine having a hollow rotatable work spindle and associated tool supporting and actuating devices including a drive shaft, the combination of driving means for the machine including a reversible driving element, driving connections between the driving element and the work spindle whereby the spindle is reversibly driven with the driving element, control means connected with the reversible driving element having a neutral and alternative [reverse driving positions, additional reversible driving connections between the driving element and the drive shaft including two reversely rotating shafts, a driven shaft and a pair of pick 01f gears mounted on said driven shaft and selectively on one of said reversely rotating shafts in meshing relation, an interlocking device including a locking element shiftable from an intermediate neutral position to alternative interfering positions to block the mounting of a pick 01f gear alternatively on one or the other of said reversely rotating shafts corresponding with the position of said control means to maintain a single direction of rotation of the drive shaft, and connections between said control means and said locking element operable to shift the locking element with the control means to each of said neutral and corresponding reverse positions.

4. In a screw machine having a hollow rotatable work spindle and associated tool supporting and actuating devices including a drive shaft, the combination of driving means for the machine including a reversible electric motor, driving connections between the motor and the work spindle whereby the spindle is reversibly driven with the motor, additional reversible driving connections between the motor and the drive shaft including two reversely rotating shafts, a driven shaft, and a pair of pick off gears mounted on said driven shaft and selectively on one of said reversely rotating shafts in meshing relation, a cover member overlying said additional reversible driving connections shiftable between alternative closed and open positions, a motor control including a switch element shiftable to a neutral and reverse running position, and an interlocking device connected with said switch element including a cover control element shiftable with the switch element and operable to permit the opening of the door only for the neutral position of the switch element, and including a pick off gear control element shiftable native interfering positions with a pick off gear supported alternatively on one or the other of said reversely rotating shafts, and thereby to maintain a directional correspondence of position between said switch arm and said reversible driving connections to maintain a single direction of rotation of the drive shaft.

5. In a screw machine having a hollow rotatable work spindle and associated tool supporting and actuating devices including a drive shaft, the combination of driving means for the machine including a reversible driving element, driving connections between the driving element and the work spindle whereby the spindle is reversibly driven with the driving element, additional reversible 8 driving connections betwen the driving element and the drive shaft including two reversely rotating shafts, a driven shaft, and a pair of pick off gears mounted on said driven shaft and selectively on one of said reversely rotating shafts in meshing relation, a cover member overlying said additional reversible driving connections shift,- able between alternative closed and open positions, control means operable to reverse said driving element, and an interlocking device including a locking element connccted with and shiftable with said control means between neutral and alternative driving positions, said interlocking device including a cover control element operatively connected with the door to permit opening of the door only for the neutral position of said interlocking device, and to permit the shifting of the interlocking and control means to either running position only for the closed position of the cover, said interlocking device including additionally a pick off gear control element shiftable from an intermediate neutral position, alternative interfering positions to block the mounting of a pick off gear alternatively on one or the other of said reversely rotating shafts corresponding with the position of said control means and thereby to maintain a direction correspondence of position between said control means and said reversible driving connections to maintain a single direction of rotation of the drive shaft.

References Cited in the file of this patent UNITED STATES PATENTS 894,232 Richards July 28, 1908 1,527,247 Bouillon Feb. 24, 1925 1,997,810 Cole Apr. 16, 1935 2,383,958 De Vlieg Sept. 4, 19.45 2,568,675 Winchell Sept. 18, 1951

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