US1926214A - Safety device for multiple grinders - Google Patents

Description

Sept. 12, 1933. c. T. RAULE 5,

I SA FETi' DEVICE FOR MULTIPLE GRINDERS Filed Apri1 17, 1929' 4 Sheets-Sheet 1 1&1.

1 N VEN TOR ATTORNEY Sept. 12, 19334 c. T. RAULE 1,926,214

SAFETY DEVICE FOR MULTIPLE GRINDERS I Filed April 17, 1929 4 Sheets-Sheet 2 pt 12, 1933. c. T. RAULE 1,926,214

SAFETY DEVICE FOR MULTIPLE GRINDERS Filed April 17, 1929 4 Sheets -Sheet 3 Iu erdfm fllyfo dfjzmde Sept. 12, 1933. T, RAULE 1,926,214

- SAFETY DEVICE FOR MULTIPLE GRINDERS V Filed April 17, 1929 4 SheetS-Sheet 4 IN VEN TOR A TTORNEY Patented Sept 12, 1933 UNITED STATES PATENT" OFFICE My invention relates to multiplegrinding machines in which duplicate grinding units are mounted at spaced intervals around a turn-table and the grinding operation is completed at each unit preferably during a single rotation of the table, work pieces being loaded into the units as they pass a loading position, subjected to traverse grinding with a progressive feed between the wheel and work until ground to size at which time a suitable sizing device automatically stops further grinding as by stopping the feed and removing the wheel from the work, all preferably before they reach an unloading position adjacent and somewhat back of the loading position, the invention having particular reference to a safety device normally auxiliary to the sizing device of the prior art.

A purpose of my invention is to utilize determinative movement of sizing devices on the individual grinding units to eiTect automatic stoppages of the turn-table as the units successively reach a designated point unless they have completed their grinding operations upon the work pieces in the holders of the units. I may mount the sizing devices upon the wheel units or upon the holder units and use their determinative movements incident to the work pieces of the units coming to size either to make or to break an energizing circuit controlling the shut-down. I preferably stop the turn-table automatically as each unit reaches a designated point of the machine unless there is a determinative movement of the sizing device at the unit such as to close an electric circuit to avoid shut down.

In the preferred form a circuit is closed to avoid shut-down each time a unit approaches the designated point unless finish grinding has riot been completed by the unit by the time the unit reaches the designated point in which the circuit fails to close and the shut down takes place. Preferably traverse grinding continues during the shut down of the turn-table until the grinding has been completed when the determinative movement of the sizing device closes the circuit of the magnet and releases spring-retracted shut down mechanism which springs back to start the rotation of the turn-table.

I have elected to show a few only of the many forms of my invention, selecting forms that are practical and efficient in operation and which well illustrate the principles involved.

Figure 1 is a diagrammatic top plan view of a multiple grinding machine embodying my invention. For the sake of simplicity and clearness of illustration many of the parts have been removed and no attempt is made to maintain scale relations between different parts and the view is intended to illustrate details of the present invention with a conventional showing of any multiple grinder of the prior art and comprising a turn-table, grinding units spaced around the turn-table, each unit being made up of a wheel and workholder and individual sizing devices controlling the feed between the grinding wheel and the workholder and of the positioning of the wheel with respect to the holder, a determinative movement of the sizing device of a unit by reason of a workpiece of the unit coming to size automatically stopping the feed between the wheel and holder and raising the wheel from grinding 7 position without afiecting the rotation of the turn-table.

Figure 1a is a view corresponding generally to Figure 2 of U. S. Reissue Patent 16,141 to J. G. McDonough, entitled Internal grinding machine, the view being modified with respect to details and being provided to illustrate mechanism of the prior art intended to be conventionally shown in Figure l and described in detail in the McDonough patent, and in itself relevant to the present invention only in so far as it more clearly discloses mechanism of the prior art and the adaptation thereto of the present invention.

Figure 1b is a fragmentary and diagrammatic view corresponding to an elevation of Figure 1a and broadly to structure shown in Figure 7 of the Reissue Patent 16,141 but provided with the type of sizing device illustrated in Figure 2 of the present application and including a diagrammatic showing of electrical connections and their connection to portions of the operating details of the mechanism, the diagrammatic portion of the figure being in general accord with the Mc- Donough Figure 36, and detail operating members thereof being shown in their actual positions in the main portion of the figure and again diagrammatically in the diagrammatic part of the figure.

Figure 2 is a fragmentary elevation of one of the grinding units, to enlarged scale, showing electrical connections with one form of sizing device.

Figure 3 is a top plan view of Figure 2 showing a portion of the supporting structure of the wheel unit omitted in Figures 1 and 2.

Figure 4 is a diagrammatic top plan generally similar to Figure 1 but showing a somewhat different form of turn-table and shut down mechanism.

Figure 5 is a diagrammatic sectional elevation ll through a work-holder showing a different form of sizing device from that seen in Figure 2.

Figure 6 is a diagrammatic view of a different form.

Like numerals refer to like parts in all figures.

Describing in illustration and not in limitation and referring to the parts:-

In the structure illustrated in Figure 1 stationary supporting structure 9 carries the turn-table 10 of a multiple unit internal grinding machine which in turn carries grinding units 11 at spaced intervals around its periphery.

Each grinding unit comprises the usual traversing grinding wheel 12 and work-holder 13 and also mechanism 11a for effecting rotation of the individual workholders on their own axes and for effecting an automatic feed between the work and wheel at each unit during traverse grinding and a sizing mechanism 11b for stopping grinding automatically as soon as the workpiece comes to size, normally by stopping the feed and removing the wheel from the work, work pieces being fed to the work-holders as they pass a designated point 14 of the machine after which traverse grinding begins and continues at any piece until the piece has been ground to finish size when the sizing device automatically stops the grinding, all before the work piece has completed a single rotation about the axis of the turn-table.

It is essential in many cases that traverse grinding should not continue at any grinding unit 11 beyond some designated point 15 of the common orbit and my device insures that the turntable will stop as any grinding unit reaches any such designated point of the orbit, preferably to permit completion of traverse grinding while the turn-table is stationary with an automatic resumption of rotation when the grinding operation of the unit at the designated point is completed.

The turn-table is rotated by a drive shaft 16, bevel gears 17 and 18, shaft 19 and gears 20 and 21, and its rotation is preferably independent of the operation of the grinding units,-which are all alike, of any suitable form and operated in any suitable way, irrelevant to the present invention and optionally of the prior art.

The drive shaft carries adjacent drive and idler pulleys 22 and 23 and is journaled in suitable bearings 24 and 25, a driving belt 26 passing between the prongs of a slidable belt shift 27 for moving the belt to either pulley, the shift device being adapted to slide to either end of a suitable stationary guide 28 for positioning the belt upon either pulley.

The slide is operatively connected by a link 29 to an arm 30 of a rocker member 31 that is springpressed at 32 toward its position at which the belt is on the drive pulley to maintain rotation of the turn-table.

The rocker 31 comprises a vertical shaft 33 suitably journaled on the supporting structure and arms 30 and 34 fastened to the shaft at lower and upper ends thereof, the arm 34 extending radially toward the turn-table and the arm 30 operating the belt shift.

The arm 34 of the rocker presents a movable member 35 that normally presses toward a position at which it will be engaged by successive lugs 36 on the turn-table but is adapted to outward movement to avoid contact with these lugs. Any engagement between one of the lugs and the member 35 results in an angular movement of the rocker to stop the turn-table.

The movable member 35 comprises a swinging armature pivoted at 37 upon the outer end of the arm 34 and spring-pressed outwardly at 38 toward a position at which it will be engaged by the successive lugs unless drawn back against the action of the spring by an electro-magnet 39 mounted on the arm 34 back of the armature 40 on the swinging arm 35. I

The circuit of the electro-magnet includes a stationary external portion 42 and cooperating interchange portions 43 on the turn-table at the individual grinding units.

The turn-table brings the interchange portions 43 of the individual grinding units successively into position to cooperate with the external portions, terminals 44 and '45 of the adjacent interchange portion then sliding over terminals 46 and 47 of the external portion, the range of angular movement of the turn-table during which there is connection between the terminals of any interchange portion and the stationary terminals 46 and 47 of the external portion including and being slightly wider than that at which the swinging armature 35 may be engaged by thecorresponding lug 36 of the turn-table.

Each individual circuit portion 43.on the turntable includes spaced contacts 48 and 49 that are only closed by determinative movement of the sizing device, a movement which brings the contacts together when the work piece grinding at the unit with which the device is cooperating comes to size. 195

Normally after a work-holder has received a work piece while passing a definite loading position 14, traverse grinding with a progressive feed between the wheel and work begins almost immediately and continues until stopped by the sizing device when the piece is ground to size.

'As this is of the prior art and may be of the form described in the McDonough patent, it is believed unnecessary to describe the mechanism whereby a determinative movement of a sizing device stops the feed between the workholder and grinding wheel and lifts the wheel from the workholder without affecting the normal continued rotation of the turn-table.

Whatever the form of sizing device this device mounted upon each grinding unit will effect a determinative movement when a piece has been ground to size to stop grinding and to lift the grinding wheel away from the work.

Usually the piece will come .to size with an automatic lifting of the wheel from the work and normally also an automatic stopping of the relative feed between the wheel and work before the grinding unit reaches a designated point at which the lug 36 of the unit is adapted to engage the swinging armature 35 on the rocker, and in this event when the work piece comes to size and the table has moved into position to bring the terminals'of the interchange portion of the circuit to engage the cooperating terminals of the external portion of the circuit the magnet is energized causing the swinging armature to be drawn back into position to avoid engagement with the advancing lug 36 of the unit so that the rocker 31 is not 5.... ted and the rotation of 14L the turn-table continues.

In the event, however, that the work piece has not been ground to size by the time the lug of the unit reaches position to-engage the swinging armature the circuit of the magnet is still open, the contacts 48 and 49 at the sizing device having not yet come together, and as a result the swinging armature is engaged by the lug 36 with a resultant angular movement of the rocker that stops the turn-table.

Preferably the traverse grinding continues without interruption after the turn-table stops until the piece comes to size. As soon however as the piece comes to size the magnet 39 is energized due to determinative movement of the sizing gauge bringing the contacts 48 and 49 together, and the swinging armature swings outwardly from the lug 36 against the outward pressure of the.spring 38 which permits the spring 32 to move the rocker 31 into position to start the turn-table again. i

In Figure 1 the rocker member 31 is illustrated as controlling the position of a belt 26 to determine the rotation or non-rotation of the turn-table. Obviously, however, the particular connection by which the rocker determines the rotation or non-rotation of the turn-table is immaterial and irrelevant to the present invention and in Figure 4 I have omitted the operative control between the rotation of the rocker member and the rotation of the turn-table.

The sizing device may be mounted either upon the wheel or work-holder portions of the grinding units and for this reason I show the sizing devices mounted upon the individual wheel units in Figures 1 to 3 while in Figures 4 and 5 the sizing devices are mounted upon the individual work-holders.

The sizing devices shown in Figures 1 to 3 are generally similar to the sizing device disclosed and claimed by me in my U. S. Patent No. 1,225,858, dated May 15, 1917, entitled Automatic sizing device, and comprises spaced contact members 48 and 49 having relative screw adjustment at 51 and'mounted at the upper ends of pivoted rocking members 52 and 53.

The rocking members may be alike or opposite counterparts and are pivotally mounted at 54 upon a sleeve 55 fastened to a tubular casing 56 of the spindle 57 of the grinding unit. They'extend downwardly into the work piece, their bulging ends 58 sliding up and down against the interior of the work piece during traverse grinding, and the members being spring-pressed toward spreading at 59.

The rotation of the work piece and the traverse of the wheel unit are movements that are relatively slow so that any wear between the bulging ends of the rocking members and the interior surface of the work piece is insignificant. The rocking arms 52 and 53 move up and down with the traverse movement of the grinding wheel but have no movement of rotation, being mounted upon the sleeve casing of the wheel spindle, the casing not rotating.

Figures 1a and 1b have been inserted merely to more definitely relate the disclosed structure of the invention to structure of the prior art and to avoid the need for describing a multiple grinding machine in any great detail in that the said patent gives a detail description of one form of multiple grinding machine.

Figures 1a and lb show an embodiment of my invention applied to a multiple grinding machine in general accord with the machine disclosed in the said reissue patent except that the machine operates with the sizing device of the applicants Figure 2 instead of that described in the said reissue patent and illustrated in the applicants Figure 5, the applicants invention using either form of sizing device alternatively.

The lugs 36' to be mounted at spaced intervals around the turn table 10, one for each grinding unit, must of course be located to clear the supporting structure, the best vertical location being dependent chiefly upon the dimensional relations and relative clearances of the turn table and its supporting structure, for example, in Figure 1b there appears to be ample clearance near the bottom of the turn table at 80, or at 81 around the periphery of the main gear of the turn table, or as illustrated upon a ring 10' fastened to the turntable by suitable brackets 10 Referring to Figures 1a and 1b the turn table 10 rolls on wheels 82 about a circular track 83, that is, carried by a main bed frame 84, being rotated as already described and as clearly indicated in Figure 1a from a shaft 16 carrying drive pulleys 22 and 23 respectively whereby a belt 26 when on the drive pulley 22 rotates the turn table and the turn table ceases to rotate if the belt is shifted from the pulley 22 to 23.

The grinding units 11 are all alike, each unit comprising the grinding wheel and work holder units. I

The wheel unit comprises a carriage 86 which is mounted in a vertical slideway portion 87 of the turn table and vertically positions a trip rod 88 that carries different actuating members that respectively-determine the reversals of the vertical movements of the carriage, the opening and closure of control circuits of the unit and effect the ratchet feed or feeds of the unit. The trip rod slides in bearings 89, and has a considerably wider range of travel than that of the carriage 86, moving up and down with respectively upward and downward movements of the carriage.

The carriage is actuated by a screw 90 vertically movable with the carriage, 'a nut 91 carrying a beveled gear at 92 that is housed in the vertically stationary frame structure, the nut being driven in reverse directions by gearing 92 and clutch 93 that is in turn driven alternatively by the beveled gears 94 and 95 according to the position of a rocker 96.

The beveled gears 94 and 95 are driven continously in reverse directions by shafting 97 that makes operating connection to reduction gearing 98 that is in turn operatively connected to a main drive shaft 99.

The work holder is carried by a horizontally movable saddle 100 which is positioned by a feed screw 101, a ratchet feed mechanism at 102 operating the screw, being itself actuated by suitable cams 103 on the trip rod and intermediate mechanism 104.

The work holder is rotated by belt and pulleys at 105 from the reduction gearing 98 and is in turn operated by the drive shaft 99.

The main drive shaft driven in any suitably way not shown carries a friction Wheel that makes driving connection at 106 with mechanism 106 actuating the grinding wheels.

The main shaft thus operates at 106 to rotate the grinding wheels, operates at 97 to effect the vertical movements of the wheel carriages and operates at 105 to rotate the work holders, and other actuations including the feed between the work and wheel, the reversals in the direction of vertical movements of the wheel carriage and the closure and opening'of contacts in the circuits of magnets 107, 108, 109 and 110 are effected by suitable members on the trip rod 88. The trip rod 88 is indicated in Figure 1b in its true position in the main portion of the figure and fragmentary portions being illustrated offset to the left to show the electrical and other actuating connections.

In operation a work piece is suitably inserted in any holder as the holder is slowly passing the position 14 of Figure 1, the wheel at this time being raised and traversing up and down well above the work holder.

During the high traverse the actuating head 111 of the clutch lever 96 is engaged alternately by trip screws 112 and 113, the resultant movements of the clutch lever reversing the up or down movement of the carriage. The switch 114 is at this time in its open position. After inserting a work piece, an operator momentarily closes the switch 114. As a result, during the downward movement of the carriage the magnet 110 becomes energized from the battery 115, switch 114, magnet 110, contacts 116, 117 and 118, back to the battery.

Energizing the magnet 110 pulls out the lower latch 119 of the head 111 making the head inoperative to reverse the clutch, so that the wheel carriage travels on down to its low and grinding position, the magnet 110 de-energizing when the contact 117 passes downward beyond the contact 116.

Traverse grinding now begins, the wheel moving down through the interior of the work piece and reversing when it reaches the position shown in Figure 1b by the clutch head 111 being engaged and downwardly deflected by the trip screw 120, and again reversing at the top its traverse when the trip screw 121 upwardly deflects the head 111.

This movement up and down with traverse grinding continuous until the piece has been ground to size, at which time circuits 0 are closed at the contacts 48 and 49 to stop the feed between the holder and wheel units and the wheel is moved up to its high traverse above the work.

Normally a piece will have been ground to size before the unit has been progressed to a position at which it would interfere with an easy removal of the finished piece. When the work comes to size the contacts 48 and 49 come together, the magnet 107 energizes through contacts 48 and 49, battery 115, contacts 122, 123, and 124, magnet 107 back to the contacts 48 and 49; the magnet shifting the feed pawl 125 to an inoperative position. Similarly, the magnet 108 energizes through the contacts 48 and 49, battery 115, the magnet 108, back to the contacts 48 and 49, the magnet shifting the feed pawl 126 to its inoperative position.

The magnet 109 also energizes as the wheel unit is moving upward, the energizing current including the contacts 48 and 49, the battery 115, contacts 127, 128 and 129, magnet 109 back to the contacts 48 and 49.

The energized magnet 109 retracts a latch 130, making the actuating head 111 inoperative to reverse the clutch when the head is engaged by the trip screw 121, the wheel moving up to an elevation at which it will be out of the way of the work.

The circuit of the magnet 109 de-energizes when the slide contact 128 moves upward beyond the contact 127 and as a result the wheel continues to traverse in its high position, reversed by the trip screws 112 and 113 as already described and at an elevation to be out of the way of work removal and work charging operations at the work holder.

Normally thisv raising of the wheel to separate the wheel and work takes place before the unit comes in position to efiect an energization of the magnet 39. It will be understood that the batteries 115 and 61 and the winding of the magnet 39 are selected to adapt the magnet 39 to remain inoperative to shift the rocker 40 unless the sizing device has brought the contacts 48 and 49 together.

The feed is stopped by energizing the magnets 107 and 108. It will be understood that the illustration in the McDonough patent shows two feeds but that while the sizing device illustrated is well adapted to operating a plurality of feeds, it has not been so described and for this reason both feeds are shown as stopped by the coming of the work to size.

The sizing device illustrated in Figures 4 and 5 is in general accord with that disclosed in Mc- Donough Patent No. 1,497,574, dated October 31, 1921, entitled Internal grinding machine and is mounted upon the individual work-holders instead of on the wheel unit.

The battery 61 energizing the circuit of the magnet 39 is desirably in the external portion 42 of the circuit, as illustrated in Figure 1, unless conditions irrelevant to the present invention make it desirable to have individual batteries for the individual sizing devices, as shown in Figures 4 and 5 where other circuits than that through the magnet 39 are closed by determinative movements of the gauges irrespective of the position of the unit, and each unit is provided with an individual battery 61 or other source of current.

The sizing devices of Figures 4' and 5 are all alike, each including gauge pins 62 and 63 mounted transversely in the upper end of a vertically guided and upwardly pressed gauge carrier 64 that is continually co-axial with the work piece 65.

The carrier 64 is pressed upwardly at 66 by the upper end of a plunger 67 that is slidably mounted in a tubular guide 68, the upwardly directed end of the plunger telescoping into a downwardly directed bore of the carrier and the guide 68 being rigidly fastened to the turn-table. The plunger is pressed upwardly by suitable springs 69 tnd 70 that surround a downwardly extending portion of the plunger on opposite sides of a transverse contact member 71. The contact member 71 is movable with respect to the plunger and is vertically positioned by the compression of the springs 69 and 70 which in turn is determined by the vertical position of the plunger.

The springs and intermediate contact member 71 are compressed between a guide member 72 fastened to the turn table and a suitable shoulder 73 on the plunger.

The upper gauge pin 62 has a length slightly less than the desired bore of the finished work piece while the lower pin 63 has a length equal to the bore of the finished piece.

After loading traverse grinding continues with a relative rapid feed between the wheel and work piece by mechanism irrelevant to the present invention but described in the McDonough patent and indicated diagrammatically at 1111 and 111) until the internal bore of the piece comes to a size permitting the pin 62 to follow the traversing wheel upwardly into the work piece, closing an electric circuit through vertically movable contacts 74 and 75' as described in the McDonough patent to reduce the rate of feed.

Traverse grinding continues at the reduced rate of feed until the bore of the work piece admits the lower pin 63 which results in an increased range of upward travel of the plunger and which may be used to stop the feed altogether and raise the wheel from the work by known means irrele vant to the present invention and at the same time accord with present invention closes contacts 48' and 49 of the interchange portion 43 of the circuit of the magnet 39, and thereby pre vents stoppage of the turn-table if the work piece has come to size before the lug 36 of the unit has engaged the swinging armature 35 or again starts the turn-table if the piece has not come to size until there has already been a cooperating engagement between the lug 36 and the swinging armature 35 that has resulted in stopping the table.

The fixed contact members 76 showncooperating with the contact member '71 are used to effect operations disclosed in the McDonough patent and irrelevant to the present invention.

In the structure shown in Figures 1 to 3 and Figures 4 and 5 the determinative movement of the sizing device is used to prevent an operation that would otherwise stop the turn-table so that any failure in making the electric circuit will result in stopping the turn-table until the circuit or anything out of order has been fixed up.

Obviously, however, I may use the determinative movement of the sizing device when the piece comes to size to break a circuit that would otherwise be operative when the unit reaches a given position to stop the turn-table and I have illustrated this in Figure 6.

In Figure 6 rotation of the turn-table is controlled in any suitable way by the position of a rocker "l7, pivotally supported at 72, springpressed at '73 to a position permitting rotation of the turn-table and adapted to be pulled down by a magnet '74 to stop the turn-table.

The turn-table rotates unless the magnet is energized and is stopped each time the terminals 44' and 45' of one of the interchange circuit portions engages the cooperating stationary terminals 46' and 47' of the external portion of the circuit, unless a determinative movement of the safety device has separated contact members to break the circuit, thereby preventing stoppage;

The circuit of the magnet includes stationary terminals 46' and 47' adjacent theturn-table and interchangeable circuit portions 43' at the respective grinding units, each of which is pro-' vided with terminals 44' and 45 adapted to engage the terminals 46' and 47' at the desired designated point of the machine.

Each internal circuit portion 43 includes contacts '78 and '79 that are relatively closed until there has been determinative movement of the sizing device to separate them.

If the terminals 44' and 45 engage the cooperating external terminals before the determinative movement of the sizing device has separated the contacts '78 and '79 a resultant energizing of the magnet stops the turn-table, preferably with out affecting continued traverse grinding at the unit.

As soon as the piece at the unit comes to size there is a determinative movement at the gauge that breaks the circuit through the magnet and releases the control member 77 causing the turntable to again rotate.

0n the other hand if the piece has come to size, as should normally be the case before engagement between the terminals 44 and 45 with the external terminals 46 and 47' there will be no energizing of themagnet, and no stopping of the turn-table because determinative movement of the sizing device has separated the contacts '78 and 79.

It will be understood that the sizing devices are nearly always interchangeably applicable to any multiple grinder of the type indicated, for example that any one of the devices may be applied to the structure of the McDonough patent. The terminals 44 and 45 of Figure 2, 44 and 45' of Figure 6, 44 and 45 of Figure 5 being in each case suitably included in an electric circuit C of the McDonough patent adapted to simultaneously stop the feed between the wheel and work unit and to raise the wheel away from the work.

In all the forms shown a sizing device that in the prior art has hitherto been used merely to stop thegrinding when the workpiece is ground to size is here used to electrically control mechanism for shutting down the turn-table if the grinding operation at any unit is still incomplete when the unit reaches any designated point beyond that at which it is deemed unsafe or undesirable for the unit to go during traverse grinding.

In Figures 1 to 3 I mount the sizing device upon the wheel unit and use the determinative movement of the sizing device to prevent a stoppage that would otherwise take place. The form shown in Figures 4 and 5 is different from that of Figure 1 to 3 chiefly in mounting the sizing device upon the work-holder instead of upon the wheel unit, using, however, a different form of sizing device.

The form shown in Figure 6 differs from the other forms in that the shut down is normally prevented by breaking a circuit instead of making one, the latter form being perhaps less advantageous in that failure of the current in the circuit would permit continued rotation of the turn-table, while corresponding failure in the other forms would have to be corrected'before the turn-table would be operative.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such in so far as they fall within the reasonable spirit and scope of my invention.

Having thus described my invention, what I claim as new and desire by Letters Patent is:-

1. In a multiple grinding machine, supporting structure, a turn-table mounted thereon, and grinding units mounted at spaced intervals around the table, said units having a common orbit and being adapted to receive duplicate work pieces while passing a loading position of the units and to traverse grind the pieces to definite size before the units again reach the loading position in combination with a shift device adapted to determine the rotation or non-rotation of the turn-table, sizing devices upon the individual units each adapted to determinative movement when the work piece of the unit comes to size and means adapting the determinative movement of the sizing device to determine the operation of the shift device while the respective units are successively at a designated portion of the common orbit.

2. In a multiple grinding machine, stationary supporting structure, a turn-table mounted thereon, and grinding units mounted at spaced intervals around the turn-table in combination with a device adapted to stop the turn-table when any grinding unit is at a designated portion of the common orbit of the units and sizing devices mounted upon the individual units adapted to determinative movements when the work pieces of the units come to size to effect a separation of the grinding wheel from the work, and connections adapting each sizing device after its determinative movement and when its grinding unit is in the said designated portion of the orbit thereon to make the operation of the stop device inoperative.

3. I n a multiple grinding machine, supporting structure, a turn-table mounted thereon and grinding units spaced around the turn-table, in combination with lugs at spaced intervals around the turn-table, one for each grinding unit, a shift device adapted to determine by its position the rotation or non-rotation of the turn-table and at its normal position permitting the rotation of the turn-table, a rocker on the shift device having one position at which it is in the path of the successive lugs and at which it is adapted to be engaged by an approach lug to adapt the lug to move the device to a shift position to stop the rotation of the turn-table, resilient means pressing the rocker toward its one position, an electromagnet adapted when energized to move the rocker out of the path of the lugs, sizing devices mounted upon the individual grinding units adapted to determinative movements when the work pieces at the units come to size whereby to effect a separation of the grinding wheel from the work and electrical connections adapting each sizing device after its determinative movement and while its grinding unit is in a designated portion of the orbit to energize the magnet.

4. In a multiple grinding machine, supporting structure, a turn-table mounted thereon, grinding units spaced around the turn-table having independent operation from that of the turntable, a rocker member adapted to stop the rotation of the turn-table and spring pressed toward position to maintain rotation of the turn-table, lugs mounted at spaced intervals around the turn-table, one for each grinding unit, a magnet and swinging armature mounted upon the rocker, the armature pressing toward a position in the path of the lugs and adapted to be pulled out of said position by the magnet, a sizing device mounted upon each unit adapted to determinative movement when a work piece in the unit comes to size, and an electrical circuit through the magnet and including contacts closed by the determinative movements of the sizing devices.

5. In a multiple grinding machine, supporting structure, a turn-table mounted thereon, grinding units spaced around the turn-table, having independent operation from that of the turntable, a rocker member adapted to stop the rotation of the turn-table, means pressing the rocker toward position to maintain rotation of the turn-table, lugs mounted at spaced intervals around the turn-table, one for each grinding unit, a magnet and swinging armature mounted upon the rocker, the armature pressing toward a position in the path of the lugs and adapted to be pulled out of said position by the magnet, a sizing device mounted upon each unit adapted to determinative movement when a work piece in the unit comes to size,' an electric winding for the magnet, interchange circuit portions on the turntable at the sizing devices each including contacts closed by the determinative movement of its sizing device, and connections adapting the interchange circuit portion of each unit to be in cooperative relation with the winding while the grinding unit of the interchange circuit portion is at a designated portion of the common orbit of the units and the lug of the unit at the swinging armature of the rocker.

6. A multiple rotary grinding machine characterized by supporting structure, a turn-table mounted thereon and grinding units spaced around the turn-table to efiect-their grinding operations upon individual work pieces during a single rotation of the table in combination with mechanism adapted to stop the rotation without interrupting and for the completion of the grinding and a sizing device control of the mechanism.

7. A rotary grinding machine of the character indicated, including a turn-table, grinding units spaced around the table, a sizing device at each unit adapted to make a determinative movement when the workpiece comes to size, mechanism adapted to stop the rotation of the table, and a control thereof operative successively by the individual sizing devices as they successively attain 2. specific angular position of their orbits.

CLIFFORD T. RAULE.

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