US2403160A - Grinding machine - Google Patents

Description

' July 2, 1946- s. WQODBURY GRINDING MACHINE Filed Jan. 6, 1944 2 Sheets-Sheet 1 July 2, 1946.

' s E. WOODBURY GRINDING .MACH INEI Fil'ed Jan. 6 1944 2 Sheets-Sheet 2 Fig.4.

Fig. 5.

Patented July 2, 1946 GRINDING iuncnmn Stephen E. Woodbury, Beverly, Mass; a's'signor to Reid Brothers Company, In'c.,'Beverly, Mass, a corporation of Massachusetts Application January 6, 1944, Serial No. 517,208 3 This invention relates to 'grinding machines and consists in certain improvements in the start-- mg and stopping mechanism therefor designed to increase the efficiency, precision and safety of such machines in operation and their convenience of control by the operator. 1

The invention is herein shown in its application to a surface grinding machine of the character more fully disclosed in my pending application Serial No. 500,078 filed August 26, 1943, which matured as Patent 2,390,978 on Dec. 11, 1945, and to which reference may be had for details of construction not herein shown. It. will be understood, however, that the invention is not restricted to grinding'machines of that or of any specific type but is of general application.

An important feature of the present machine consists in a single starting lever r handle movable for the two functions of engaging or disen gaging a clutch interposed between the table and its motor and also for opening or closing a switch controlling the flow of current to the table motor.

In'grinding machines as heretofore constructed, it is customary to provide a clutch in the train of mechanism'for operating the table and to provide an off and on switch in the motor circuit. Heretofore the clutch and switch have been separate and distinct and'have been arranged for separate operation, that is to say, the user has been obliged to throw the switch as one operation and then to shift the clutch as a separate and distinct operation, Under these conditions the table motor is often left idling at full speed while the clutch is disengaged. Moreover an objectionable shock occurs when the clutch is engaged with the motor running at full speed. The elimination of this shock is desirable for work where a high degree of precision is required. The present invention provides mechanism whereby the table motor is stopped by cutting off its operating current at approximately the same time that the motor is mechanically disconnected from the table; The operator does not have to perform an extra operation nor can he forget to turn off the table motor when changing to hand operation. With this end in view an important feature of my invention consists in a self-closing switch in the motor circuit which is arranged to be automatically opened whenever the starting handle is'returned to its initial position in the course of its clutch disengaging movement. Means are also provided for detachably latching the starting handle in running position, that'is to say,with

the motor switch closed and inechanicalconnec- 12 Claims. (CL 51-92) hand side of the frame In.

byengagement of the clutch; vl urth er, the mech- "anism of my invention is preferably designed-to insure closing of the motor circuit shortly before engagement of the clutch so that the clutch is engaged before the motor has acquiredits full speed of rotation, thereby eliminating or largely reducing'the shock caused by a more abrupt pick-up of the table operating mechanism. 7

These and other features of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings, in which Fig; lis a fragmentary view in perspective of the grinding machine,

Fig. 2 is a view in perspective of the driving mechanism unit, i r

a Fig. 3 is a skeleton view in perspective of the controlling mechanism, and

Figs. land 5 are wiring diagrams.

In its general organizationthe illustrated machine includes a box frame H] from the rear side of which rises an upright column I l. The grinding wheel I2 together with its spindle and individual driving motor (not shown) are mounted for vertical adjustment in a slide carrier movable upon thecolumn ll.- In the top of the machine frame in are provided transverse ways in which rests the cross slide l3. The slide I3 is provided with longitudinal ways in its upper face and in these slides the elongated work table l4 herein shown as equipped witha magnetic chuck IS. The work to be round is clamped upon this chuck and fed back and forth beneath the grinding'wheel l2; r

ing longitudinal movement to the table M. This motor, its driven train and its controlling mechanism are organized as a unit and mounted upon a panel20 which is removably secured to the left mounted externally on the panel 20 and directly connected to a reducing gear set enclosed in a casing 22 and supported by a bracket 2| formed as a part of the panel. The out-put shaft 23 of the reducing gear carries the fast member 24 of a toothed clutch and with this cooperates a corresponding loose member 25 which is formed as part of a sleeve carrying a driving pinion 26. The loose member 25 of the clutchis controlled by a forked shipper 2'! carried by a shaft 31 disposed parallel to the shaft 23 and supported at one end in the bracket 2| and at theother in a second tion established betweenthe motor and the table panel 20." A. coil compression spring 40 surrounds register with each other.

' already explained. v V

The starting and stopping switch for the motor shipper 21 is moved toward the right by the oper- 'ator in opposition to the spring 40, the clutch is engaged and the drivingpinion 26 set in rotation.

The reduction inspeed between the motor I! and the out-put shaft 23 may be in the order of 7 to 1.

Rotation of the pinion 26 effects the longitudinal movement of the table |4 through chain and sprocket mechanism fully disclosed in. my we.

pending application but not' herein illustratedsince it forms no part of the present invention.

However, it will be understood that whenever the;

pinion 26 is set in rotation the table |4is thereupon moved longitudinally in a direction COMB-1 sponding to the direction of rotation of the pinion. 7 The motor I1 and the pinion 26 are reversed, in

direction at each end of the table movement by mechanism controlledby adjustable dogs on the table l i, one of whichfdog's I6 is shown in Fig. 1.

The startinghandle 35 of the machine is mounted on a transverse shaft 3| journaled in the .panelZil and having a shouldered sleeve 32 pinned to its outer end. The handle 30 has a "hub 33 in which is formed a shoulder arranged to engage with the corresponding shoulder in the sleeve 32 and so determine the initial position of the handle as shown in Fig. 2 while providing a limited angle of lost motionbefore the handle beginsto turn the shaft 3| in its starting stroke. At itsinner end the'shaft 3| is provided with a downwardly extending arm 34 to which is pivotally attached-a'block'35. Ih'e block 35 isarranged toaslide in'vertical ways formed in one side face of a sleeve 36 which is fast upon the :shaft 31. and to which the shipper 21 is connected.

It will be apparent that as the starting handle is 4 the bar. A spring 54 normally urges the bar 5| toward the left so as to close all four contacts 52-53. The inner end of the rod 45 is shaped to meet the left hand end of the bar 5| when the starting handle is restored to its initial position and thereby to displace the bar 5| toward the right against the compression of the spring 54, opening the contacts and cutting off power from the motor 22. On the other hand, when the starting handle is swung downwardly as shown in Fig. 3 the end of the rod 45 recedes from the bar 5| andits spring 54 is therefore permitted to close all the contacts and start the motor while the rod continues to move idly during the further movement of the starting handle. W From theforegoing description it will be apparent that the spring 46 holds the starting .handle 31) normally in its initial position as shown in Fig. 2 with the clutch 24-25 disengaged and the switch bar 5| displaced toward the right and heldin open-switch position; When it isvdesired to set the machine in operation, the operator ha's .merely to swing the starting handle downwardly untilwthe. shaft 3| with its lug 42 is latched by the pawl 43, In this movement the starting switch is first permitted to close, by the retracting movement 'of the rod 45, and the driven shaft 23 isset .i'n'r'otation together with the clutch member 24; Continued movement of the starting 7 handle brings the end faces of the clutch'mem-' "contact. Immediately upon registering the teeth of the two clutch memb'ersthe clutch is engaged and the table |'4 set in motion; By

thistime the lug42 has been turned to a position in which it can belat'ched by the pawl 43' and the machine will continue to operate until the swung downwardly from its initial position, the a sleeve will be inoved toward the right as will be seen in'Figs.2and 3, the spring compressed and 'the clutch 24-45 engaged when its "teeth .Thearm 34 has a hub 4 I 3|"and from this hub projects upwardly a lug 42. A-shouldered pawl 43, cooperating with the lug 42, is mounted upon a stud 44 projecting in- Iwardlyfrom the panel 26. A tension spring 48 tion. Aforked link 41 is pivotally connected to the free end of the pawl 43 and this engages at its lower end with an angular rod projecting inwardly from the hub 33 of the starting handle. A: tension springdt extends between the rod 45 and a'pin on the panel 20 and tends always to swing thestarting handle upwardly to its initial jposition determined by the shoulders of the hub 33 and the sleeve 32. The link 41 has the function of swinging the pawl 43 upwardly to an inoperative position and holding it in that position while the machine is at rest. When the starting permits the pawl 43' to engage the lug 42 as 2 2 'is-c'arried'by a plate '50 mounted upon the inner face of the panel 20. The switch comprises a longitudinally movable bar 5| carrying two setsof spring: contact members 52. These icooperate' with corresponding :sets. .of stationary j contact members 53 disposed on opposite sides of surrounding the shaft ward to starting handle ,is swung upwardly with 'the'assistance of the tension 'of the spring 46; It will be understood, that, with the parts in theipo'si-.

tionsshown in Fig. 3. the spring 46. while tending tomove the handle 35' upward, is resisted by the friction between the-pawl 43 and the lug '42; with the -result that the handle remainsin the lower position shown until it' is manually moved u disengage the pawl from .the lugby means of the r'Td 4'5 and the link, At or about the instant of disengagement of'the' pawl 43 the lug 42, the shoulder on thehub 33 of the handle engages the mating shoulder on the' sleeve 32-, thus'enablin'g the handle in cooperation with the spring 4ilto restore the parts to the relativepositions shown in Fig. 12. The handle is then-held in its upper position by the spring '46.

It will be apparent that during this upward movement, the handle 30 effects disengagement ofthe clutch and opening'o'ftheswitch; I l

A hand wheel Ea ls fast to a short shaft journaled in bearings projecting from the frontof the frame l0; and at its inner end this shaft has clutch teeth for engagingcorresponding teeth on the pinion 26 when the latter is shifted by the handle 30 in disengaging the clutch.24-25.- .It

will be; seen, therefore. that when thepinion 25 is disconnected from its'p'ower driven chain fof mechanism it is connected to the hand-wheel- 28 by whichthe table I4 may be -then movedi'm'anually 'Ihe longitudinal :reciprocationsiof the table l4 take place independently of thefi'tran'sverseposition of the crossslide 3 in the machine. It .Willbe understood that the machine includes automatic mechanism for effecting a cross'feeding step before each traverse of the work beneath the-sr n heel' lg1 ln Fig: 4 is-a W r ngd-i-agram showinga three V phase motor with the self-closing "switch above [It will be'noted that when the switch is open the flow of current is cutoff in two of the service wires in each diagram,

The sleeve 36, as shown in Fig. 3, is free to move toward the left until it brings up against the bracket 39 and when free to do so the spring 40 will accordingly hold the sleeve in contact with the bracket. This in turn determines theinitial position of the arm 34, the shaft 3|, the sleeve 32 and lastly the starting handle 30.

Having thus disclosed my invention and described in detail one desirable embodiment thereof, I claim as new and desire to secure by Letters Patent:

1. In a grinding machine having a reciprocatory table and a motor for operating the table, a self-closing switch for controlling the motor, a clutch interposed between the 'motor and table, a spring for causing the clutch to disengage, and a single starting lever movable to oppose said spring and to release said switch so it will close prior to the engagement of said clutch.

2. In a grinding machine having a reciprocatory table and a motor for operating the table, operating mechanism between the table and motor including a motor-driven shaft having interfitting clutch members thereon, a starting lever, a spring tending to disengage said clutch members and arranged to be compressed by said lever, a self-closing switch controlling the operation of said motor, and means controlled bysaid lever for closing said switch when the starting lever is moved to compress the clutch spring.

3. In a grinding machine having a reciprocatory table, a motor and driving mechanism including a clutch between the motor and the table, a starting lever, a switch in the motor circuit, connections, between said lever and switch, connections between said lever and clutch, operating first to cause closing of the switch and then to cause engagement of the clutch, and means for temporarily latching the said lever in running position.

4', In a. grinding machine having a motor driven reciprocating table, driving mechanism for the table including a clutch and a motor operating circuit including a switch, a starting lever, means operated by movement of the lever in one direction for engaging the clutch and closing the switch, means operated by movement of the lever in the opposite direction for positively opening the switch, and spring means controlled by movement of the lever in the last said direction for disengaging the clutch.

5. In a grinding machine having a motor driven reciprocating table, driving mechanism for the table including a clutch and a motor operating circuit including a switch, a starting lever, means operated by movement of the lever in one direction for positively engaging the clutch, spring means controlled by movement of the lever in the said direction for closing the switch and means operable by movement of the lever in the opposite direction for eifecting the disengagement of the clutch and the opening of the switch.

6. In a grinding machine having a reciprocatory table, a detachable driving'and controlling unit comprising a panel, a motor mounted thereon, a driving train between the motor and table including a clutch, a spring for disengagingsaid clutch, a self-closing switch in the motor circuit carried by the panel,'a shaft journaled in the panel and having a starting handle at its outer end, an angular rod movable with said shaft for opening said switch, and' a shipper connected to the-shaft and movable therewith to cause the clutch to engage.

"7. 'In a grinding machine having a frame supporting a reciprocatory table; a detachable panel having a motor mounted thereon, a driving train between the motor and table including a clutch, a spring tending normally to disengage said clutch, a motor circuit including a self-closing switch carried by the panel, a shaft journaled in the panel and having a starting handle in its outer end, connections movable with the shaft for positively opening said switch, a shipper connected to the shaft and movable therewith for engaging the clutch, anda hand wheel mounted in the machine frame and operatively connected to the said driving train whereby the table may be moved when the clutch is disengaged.

8. In a grinding machine having a reciprocatory table and a motor for driving the same, a clutch interposed between the table and the motor, a switch for controlling the operation of the motor, and a single hand lever movable in one direction and having a lost motion connection for causing the switch to close and other connections for causing the clutch to engage after the motor has been started by the closing of the switch and being movable in the opposite direction for causing the switch to open and the clutch to disengage,

9. In a grinding machine having a reciprocatory table and a motor for driving the same, a clutch interposed between the table and the motor, a switch for controlling the operation of the motor, a single movable hand lever, and a lost motion connection operable by a continuous movement of the hand lever in one direction to effect closing of the switch and other connections for subsequently effecting engagement of the clutch.

10. In a grinding machine having a reciprocatory table and a motor for driving the same, a clutch interposed between the table and the motor, a switch for controlling the operation of the motor, a single movable hand lever, lost motion connections operable by a continuous movement of the hand lever in one direction to efiect closing of the switch and other connections for subsequently effecting engagement of the clutch, and operable by a continuous movement of the hand lever in the opposite direction to efiect disengagement of the clutch and subsequently opening of the switch.

11. In a grinding machine having a reciprocatory table and a motor for driving the same, a clutch interposed between the table and the motor, a switch for controlling the operation of the motor, clutch operating means for effecting engagement and disengagement of the clutch, a hand lever having a lost motion connection with the clutch operating means whereby the hand lever serves after its lost motion movement in one direction to actuate the clutch operating means to efiect engagement of the clutch, and.

means movable with the hand lever for effecting closing of the switch during the said lost motion operating means.

a 12. In a grinding machinehaving a reciprocatory table and a motor for driving the same, a clutch interposed between the table and the motor, a switch for controlling the operation of the motor, clutch operating means for efiecting engagement and disengagement of the clutch, a hand lever having a lost motion connection with the clutch operating means whereb th hand 10 lever serves after its'lost motion movement in one direction' to actuate the clutch operating 'means epoameo to efi'ect engagement of the clutch, means mov able with the hand lever for effecting closing of the switch during the said lost motion and prior to the said actuation of the clutch operating means, an automatically acting latch for vholding V the clutch operating m'eans inthe clutch engaging position, and means operable by the lost motion movement of the hand lever in the opposite direction for disengaging the latching means to release the clutch operating means and permit clutch disengaging :movement thereoi.

STEPH E? vvoomauav;

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