US361829A - martin - Google Patents

Description

v5 Sheets-Sheet 1.

(No Model.)

, H. N. MARVIN. ELECTRO MAGNETIC ROCK DRILL.

' No. 361,829. Patented Apr. 26, 1887.

INVENTQR I ATToRNEY 5 Sheets-Sheet 2.

Patented Apr. 26, 1887.

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Tina Pmmunwmpw. wuhingxm D. c.

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. H. N. MARVIN. ELECTRO MAGNETIC ROCK DRILL.

(No Model.) 5. shees-sheet 3.

H. N. MARVIN.

ELEGTEO MAGNETIC ROCK DEILL.-

No. 361,829. PatentedApr. 26, 1887.

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WI'TNESSES A TTORNEY (No Model.) 5 sheets-sheet 4.

H. N. MARVIN. ELECTRO MAGNETIC ROCK DRILL.

No. 361,829.y Patented'Apr. 26, 1887,.

WITNESSES: I n Ri AINVEIVTR W' y Y BY "7 2 l ATTORNEY N. PETERS. PhoIn-Lilhagnpher, Washington. 0.0

. (No Modell.) l 5 Sheets--Sheet `5.

H. N. MARVIN.

ELECTRO MAGNETIC ROCK DRILL.

No. 361,829. Patented Apr. 26, 1887.

la I

WITNESSES INVENTOR UNITED STATES 'PATENT OEEICE.

HARRY NORTON MARVIN, OF SYRAOUSE, NEW` YORK.

ELECTRO-MAGNETIC ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 361,829, dated April 26, 1887.

Application filed June 23, 1886.

To all whom t may concern:

Be itknown that l, HARRY NORTON MARVIN, a citizen of the United States, and a resident of Syracuse, in the county of Onondaga and State of New York, have invented certain new and useful Improvements in Electro-Magnetic Rock-Drills, of which the following is a specification.

My invention relates. generally speaking, to reciprocating tools-such as rock-drills, hammers, dental pluggers, Sta-in which the tool is reciprocated by the power of electro-magnetism.

My improvements are designed more particularly for use with rock-drills.

I have herein shown my invention embodied in an instru ment in which a reciprocating core l of soft iron moving through a helix oi wire wound in sections is employed as the agent for reciprocating the tool. At the same time it is to be understood that some of the devices herein described are applicable to instruments in which other forms of electro-magnet are employed for moving the tool.

My invention relates, first, to the means of changing the position of the commutating device by whose operation the magnet-coils are thrown into and out of action. In carrying out this portion of my invention I mount the com mutating device or the operating portion ofthe same so that it shall move with the tool or portion of the magnet operating said tool, and in such way that it may move independently ofthe same. Iconnect the commutating device with the part from which it receives motion by a catch, which is by the momentum acquired by the parts during the downward stroke of the drill released7 so that a suitable spring may move the commutating device with relation to the core and tool and throw out of action the coils by which the downward movement is produced, and at the same time throw into action coils by which"a reverse movement may be effected.

` My invention consists,also,in cushioning or checking the stroke of the instrument by setting up a counter magnetic tendency whose iniiuence serves to oppose the movement of the parts at or near the end of a stroke. I prefer to set up this counter tendency by the Serial No. 205,956. (No model.)

direct action ot' the coils acting on the core, though I do not limit myself to any particular arrangement hereinafter described, since the invention consists, broadly, in causing the core or other part to move near the end of its stroke in opposition to a counteracting magnetic pull. When a series of coils are employed for moving the core, the counter pull or tendency may be utilized by prolonging the time during which a set of coils near the end ofthe stroke ofthe core shall be kept in action, so that said core shall be obliged to move through them. This effect can be readily accomplished by the employment of the portion of my invention which consists in mounting the commutating device so that said device and the core, while they move together under some conditions, shall be capable of moving independently of one another at or near the end of a stroke.

My invention consists, also, in cert-ain details of construction and improved combinations otfdevices relating, among other things, to the circuit-changing mechanisms for bringing the coils into action one after the other.

My invention relates, further,to a means for automatically turning the tool at each stroke.

rlhe various devices and improvements con,- stituting my invention will be described in connection with the accompanying drawings, forming part of this specification, and will be then more specifically stated in the claims.

Referring to the drawings, Figure l is a. longitudinal section of a portion of an electro-magnetic rock-drill embodying my invention. Fig. 2 is an enlarged longitudinal section of a part of the device shown in Fig. 1. Fig. 3 is a side elevation and par.- tial section of the commutating device that moves with the core of the instrument. Fig. 4 is an end View of the devices shown in Fig. 3. Fig. 5 is a cross-section on the line X. X of Fig. 2. Fig. 6 is an end view of a stop or abutment at the upper endof the drill. Fig. 7 is a plan showing the arrangement of the circuit closing and breaking devices arranged exterior to the coils. Fig. Sis a cross-section of the instrument on the line Y Y of Fig. 7. Fig. 9 is a diagram showing the manner in which the circuit-closing springs are connected IOO to the coils and the relation of the commutating` device to the core, the springs, and the coils. Fig. 10 illustrates a modiiied form of commutating device embodying my invention.

A indicatesa reciprocating core of soft iron, which moves in a suitable guidetube, B, over which are wound coils of wire numbered from l to 13, inclusive, Fig. 1. Connected with the core in any suitable manner is the drill C or other tool.

D indicates the comniutating device, which acts dirctly or indirectly upon the circuit closing and breaking points or springs, and which may be of any desired form or construction.

In Figs. 1 to 9inclusive, the commutating device D is shown as a hollow tube or block provided at one side with a projecting portion, a, beveled at both ends and moving in a slot or groove, b, formed on the interior ofthe tube B. rlhe projection a operates upon a series of reciprocating pins, F,which work in holes drilled through disks E, of brass or other material, that separate the coils. rlhe pins F at their upper ends are provided with heads of insulating material which operate the springs or other parts of the circuit-closing devices that serve to bring the coils into action in the manner to be presently described.

The tube D moves with the core A, but is adapted to be shifted with relation to the same. It moves upon astem or rod, L, extending from the core, as shown, and is provided with an automatic catch or lock (one or more) consisting of a pawl, g, adapted to engage with an offset or shoulder formed on the spindle L. Three such catches are shown. A spring, h, tends normally to disengage the catch; but the latter is held locked by reason of the fact that the offset or shoulder-is slightly beveled or depressed at its portion nearer the longitudinal axis ofthe rod L, so that the catch cannot be disengaged unless the part D moves with lrelation to the stem L in a direction to bring the end ofthe pawl or catch away from the shoulder longitudinally.

Within the tube D is a spring, M, abutting at one end against the core and at 'the other against the bottom of the cylindrical cavity formed in the part D. Vhen the spring is compressed, as shown in Fig. 2, the commutating device D is locked to the stem L, so that on a movement of the parts to theleft, Fig. 2, the commutating device will move with the core in the relation shown throughout its stroke. When, however, at the end of a stroke, the tool strikes the object, the momentum acquired by the part D is sufficient to move it slightly with relation to the stem L and core and sufciently t0 permit the spring It to unlock the catch from the spindle. The spring M, which is, as stated, undery tension, at this instant moves the part D in the opposite direction, thus effecting a change of the circuit connections to the coils and cutting off the ow of current to the coils which were in action the instant the tool andy core completed vided with a head, as indicated, which acts as a stop to determine the distance to which the tube D shall move under the action of the spring M when the tube is released from connection with the core and spindle.

Attached to the tube D, at or near its end, are one or more spring cams or projections, O, which engage with the catch G and force it back into position, where it may engage with the shoulder on the stem L on completion of the reverse movement of the core, as will be presently described.

The circuit-changing springs are mounted upon suitable insulated bars or supports, d, secured to the outside ofthe coils and upon a plate, f, that extends beyond the coils and is mounted on the heads LZ BF. Secured to the same supports are contact-blocks I I, with which the free ends of springs K K tend to make connection. Beneath the springs K, but normally out of contact with the same, are springs H, which are lifted in succession by the pins F as the same are raised bythe operation of the commutating device D. rlhe springs H are normally out of contact with the springs K, but, when raised by the pins F, first make contact with springs K and then raise the free ends of said springs out of contact with the blocks I.

In the annexed drawings I have shown the pins starting with the upper end ofthe series and extending toward the end of the instrument holding the tool. The core is shown as having moved from the upper end of its path part way on its course to the opposite end of its stroke. The pins numbered 1 to 8 arc those concerned in actuating the commutating-springs toward the end of the stroke of the core to the right in the drawings, or in an upward direction, and pin 1 is the last pin acted upon. The series would extend in the opposite direction to a length depending upon the number of coils employed.

I have in the diagram omitted the springs and connections to the portion of the commutator that the core is supposed to liavejust left, for the sake of simplicity, showing the connections only of the springs which are, for the time being, concernedin the operation, or arejust about to come into action.

A set of springs similar to thosel shown would, of course, in practice he arranged opposite pins 1 to S, and arranged and connected to one another in the manner shown and described with reference to pins 9, 10, duc. They are made a continuation of the circuit passing through springs shown in the diagram in a manner obvious to electricians.

The manner in which the springs are connected to the coils is indicated more clearly in the diagram.

rEhe circuit through which current is supplied to the coilsentering, say, at a spring K-would, if none of the pins were raised, pass in series through the contact-blocks I and springs, as shown, proper connections the stroke. The end of the spindle L is profrom cach block I to the next succeeding aereas spring K of the series being made in any tion from said block to the next succeeding spring, as clearly shown in the diagram.

When any spring H is raised, the connection between the spring K and its block will be broken in obvious way, thus severing at vsuch point the continuous circuit th rough the springs K and their stops I, while at the same time connection is made between spring K and the spring H, so that the current which before iiowed directly fromspring K to theblock, and thence tothe next succeeding spring, will now be forced to low through spring H, the wires of the coil, and thence onto the next spring K, and so through the series of springs K and blocks I at all points where the pins F are not raised. It the pin Funder the next succeeding spring K be raised, then the coil corresponding to such spring will be brought into circuit through contact of said spring with the spring H beneath it. It will be apparent, therefore, that at all points where the pins F are not raised the current will pass directly through the circuit-closing devices and cannot pass to any coil, because such coil is open-circuited by reason of the disconnection of its spring H from spring K over it. At all points where the pins are raised, the coils will be in circuit through the breakage of connection between springs K and their stops and the establishment of connection at the open-circuited end of the coil by contact of springs H and K.

I prefer to arrange the commutati'ng devices so that a number of coils shall be in action at the saine time. In the present case I have shown the projection a made long enough to raise four pins F simultaneously, thus throwing into operation four of the coils. In the diagram pins 10, ll, 12, and I3 are shown raised, so as to throw into action coils correspondingly numbered, which will obviously operate t0 draw the core in the direction of the arrow. As the core and the connected commutating device D move a little farther, the pin numbered 10 will drop, thus throwing out coil l0, and at the same time pin 14 will be raised, so as to throwinto ae` tion the corresponding coil, 14. Itwill be observed that four coils are always in action in series with one another, and that coils are taken out and thrown in one at a time.

When the number of sections are always energized at the same time, and the current shifted to and from the sections singly, as described, the changes in the total internal resistance of the drill are very slight, and much sparking is avoided.

As the core moves, the current is shifted out of and into the various coils, so that the center of attraction or the resultant magnet-ie cen ter of the energized coils is kept in advance of the core, which latter is preferably short in comparison with the total length of the drillhelix. also of advantage when a short core is employed, inasmuch as the set of coils in action is always at the position of best advantage or pull wit-h reference to the core. Therefore the magnetic forceis more economically exerted and waste ot' power is prevented through the retention of coils in action when their pull upon the core is not the best.

The device for producing rotation of the drill consists of a disk or collar, M2, which is capable of rotation independently of the cylinder D, but which, if held from rotation during movement of the spindle independently of it, will cause the spindle L and connected parts to rotate. This rotation is secured through the operation ofthe pin n, carried by the sleeve or collar, which pin engages with a spiral groove, m, in the extended portion ofthe spindle L. In the end of the tube B is secured a stop, N, against which the parts abut at the end of the stroke in the direction of t-he arrow 22, Fig. 1. This stop consists of a thimble, through which the rod L may pass, but against which the collar M`- will strike. Thesurfaces of the collar and thimble which engage are suitably roughened, so that the collar will be held from rotation when pressed against the thimble or stop.

The operation of the device would be as follows: Let it be supposed that the core and commutating device are connected together, as shown in Figs. l and 2 and in the diagram Fig. 9, and that the core is moving downward in the direction of the arrow 20, Fig. l. As the core moves, the commutating device connected therewith continues to throw out pins F and to allow them to drop backone after the other, so that there is continually at every step of movement ofthe core a set of coils whose mean attractive influence is below said core. When the tool strikes the object at they end of the stroke, the momentum acquired by the parts will cause the part D to move so as to bring the end ot' the catch g out ofengagement with the oTset or shoulder on the spindle L. The spring li thereupon throws the catch to one side, and the spring M immediatelyn'ioves the commutat i ng device on its sup port L until the collar M2 brings up against the head of the spindle. The effect of this is This subdivision of the drill-helix is i obviously to cut out the set of coils which were v acting on the core at the moment the strokeis delivered and immediately to throw into action a set of'coils above the core which had just previously been instrumental in pulling the core downward. The core, tliere'ore, is now attracted in an upward direction and moves upwardly, carrying with it the commutating device which now rests upon the expanded spring and successively throwing the coils into and out ot action one at a time, so as to keep a group of coils in action continually ahead of it. As the core moves upward, the collar M2 finally abuts against the stop N, the opening` in said stop being large enough to permit the spindle L to `project through it. The core A.

and drill-tool continue, however, to move upward with their acquired momentum, although the commutating device D is brought to rest by impingement of the collar M2 against the stop. The momentum of the core is sufficient to compress the spring M, and finally to bring the spindleLinto such position that the shoulder on the same will be in position to engage with the catch g. Vhen this position is reached, the springs O throw the catches inward, and when the reverse movmement of the parts takes place the latter become locked to the spindle in obvious manner. At the time the commutating device D is stopped by the engagement of the collar M2 at its end with the thinible N, there is obviouslya set of coils in action above the core. As the cominutating device remains at rest, this set of coils obviously continues to be in circuit, and the continued movement of the core to the position where it is iinally stopped by the engagement of its upper end with the lower end of the tube D, or by the extreme compression of the spring M, ninst be obviously made in opposition to the magnetic pull of said set of coils, since by the arrangement of devices described the motion of the core independently of the commutating device D at the end of the upward stroke is sufficient to bring the.

core not only into position where the mean attracting influence of the coils would be opposite the center of the core, and thereforeinv effective to move it in either direction, but is sufficient to move it still farther or into such position that the current in said set of coils would tend to move said core in the opposite direction, or downward. /Vhen the core thus moves through coils that are in the circuit, there is a checking iniiuence exerted that serves to cushion the coreand connected parts at the end of the stroke. It will be observed that by the time the core has been brought to rest it will have moved into such position that the set of coils kept in action by the commutating device, which in the meantime has not moved, will act to immediately cause the core A to resume its movement in the opposite direction. In this latter movement the core and the commutating device move together in the relation shown in Fig. l, and the reciprocating motion is continued in the manner inst explained so long as current is supplied to the coils.

It will be seen that by 'mounting the commutating device so that it will move with the core, but so that at the same time there may be an independent movementof said core and commutating device with relation to'one another, I secure important results.

The operation of the device in producing rotation of the drill is as follows: Vhen at the end of the downward stroke the cylinder D is released and moves on the spindle L, the collar M2 moves with the part D in a longitudinal direction and turns'freely on the spindle, through engagement of the pin nwith the slot in the spindle. No turning movement of the spindle and tool is produced during this operation; but when, through reverse movement of the core, the collar M2 engages with the stop N, and is held from rotation through engagement of the ratchet-surfaces, the fur ther longitudinal movement of the spindle L results in the rotation of said spindle and of the connected tool through the action of the pin n on the spiral groove.

It will be observed that with the improved arrangements ofdevicesand connections herein described, the coils are open-circuited in succession as the pins F move inward through the engagement of the projection a, carried by the commntating device. The coils are therefore open-circuited at the moment they are thrown out of action, and therefore there is no opportunity for the circulation of retarding induced currents after the coil should cease to be effective. By this means I overcome the practical 'diiiiculty which would naturally ensue if the coils were connected together in a continuous circuit and were brought into and out of action by a spring or springs which should move over a series of contact-plates, as illustrated in Fig. 10. It will be seen, further, that the springs that supply current to the coils are adapted to make a continuous path for the current independent ot the coils, while at the same time the latter are normally open-circuited and are only brought into circuit by interrupting the continuous closed circuit, just referred to, at the proper points, and making connection between the open circuited end ofthe coil and a spring or contact of the closed circuit. This I believe constitutes a new principle of opera tion in instruments employing a set of coils which are thrown into and out of action successively, as described, to produce a continuous movement of t-he core in both directions.

It will be observed thatin myimproved apparat-us the same set of coils are used to advance and retract the core, and that, moreover, a number of sections or coils are always energized at the same time, while the current is shifted to and from but one section atatime. rlhe change in the total internal resistance of the coils is therefore slight, and comparatively litt-tlc sparking can ensue. As the length of each helix is short compared with the total length of the sections energized at any one time, the helices in action can always be kept at the position of best magnetic pull with reference to the iron core.

In my drill the blow of the tool upon the rock operates to directly reverse the drill. Whenever the drill is suddenly stopped, whether after a long or short stroke, the momentum of some moving part operates to shift the connnutating devices so as to shift the position of action of the coils. Thus the point of cut off and reversal is entirely independent of the position of the core, and a hole of several inches depth can be drilled without feeding down the drill or changing the drill-rod.

In Fig. l() I have shown a modified form of commntating device which also involves the principle of that hereinbefore described in so far as the device moves with the reciprocating core or tool and is capable of a movement independent thereof, so vthat the current'may be changed in the proper way to produce motion vin both directions by the same set of coils.

The device is also similar to that hereinbefore set forth in so far as the reversal of position of its parts is secured through the momentum of a part moving with the tool and acting when the tool strikes the object to produce a change in the/position of the commutator device.

In the arrangement of apparatus shown in Fig. l0 the coils are connected in a continuous series, as indicated, with one another, and at the points of junction between the coils connections are made to a series of contact-plates, a5. A group of coils is kept constantly in action ahead of the core by the employment of two circuit-closing springs,` b5, which are carried by a common support, but are insulated from one another in any suitable manner. Current is supplied to said springs through contact-springs c5 05,*in connection with the springs b5, and connected, respectively, to the opposite poles of a suitable source of electricity, as indicated.

The devices described are supposed to be mountedon the outside of the coils or helices giving movement to the core or tool, but, if desired, may be upon the inside of the guidetube. AThe support for the springs b5 is provided with a pin or projection, e5, that passes into a slot in the lower end ofthe rod f5, suitably connected through an arm, g5, with the reciprocating tool. The lower end of the rod f5 is made hollow,or is suitably constructed to carry a spiral spring, i5, bearing against the under side of the projection c5. The slot in the rodf5 is elongated, and during the downward movement of the rod the support for the brushes b5 is held at the bottom of the slot by the catch h5. Inthis position of the parts the coils in action are supposed to be always ahead of the core.

When the drill or tool strikes the object, the momentum of the laterally-extending portion of the catch h5 disengages it from pin e5, and the spring 'i5 thereupon shifts the commutator device, consisting of the support carrying the contact-springs, so that the pin e5 rises to the upper end-of the slot, thusshifting the current to a set of coils above those in action at the moment the tool struck, and causing reverse movement in the manner already described with reference to the other gures. The upward movement of the support for the springs b5 continues until said support abuts against the stop ki, after which time the rod f5, carrying lthe catch h5, continues its movement with the core. The catch h5 is thus raised so as to lock the rodfi to the pin e5, and the core, having continued its movement under momentum until it has passed through the coils in action, is now in position to move in the reverse direction under the operation of said coils, and

in so doing to carry -with it the commutating device through the locking together of the rod or supportf5 and the projection e5 by means of the catch h5.

It will be seen that the essential principle of operation is the same as in the case before supposed,whe1e the commutating device consists of a part, D, acting indirectly through the reciprocating-pins upon the contact-springs.

In the present instance the commutating device consists of a support, e5, carrying the springs b5. In both cases the momentum of parts moving with the drill effects a reversal of position of the commutating device, so as to produce a reverse movement o'f the core.

It will also be evident that, as in the arrangements previously described, the commutating device and the core by which movement is imparted to it can, at the end of the stroke, have a movement independent of one another, such movement in one case being the result of the action of the spring i5 when released, and in the other case producing a compression of the spring while the commutating device is held stationary against its stop.

That I claim as my invention isl. The combination, with the reciprocating core and the commutating device moving therewith, of an interposed spring connection whereby the core may continue to move after the commutating device is brought to rest.

2. The combination, with the reciprocating core and the commutating device carried thereby, of a spring and a catch or locking device whose parts are arranged, as described, so that when the tool completes its stroke the catch will be disengaged by momentum, and thus allow the spring to act so as to shift the commutator.

3. The combination, with the reciprocating core, of a commutating device carried by the core,a catch connecting the two and automatically disengaged by momentum at the end of the stroke, a spring for shifting the commutating device in one direction, and a spring located at or near the end of the stroke in the opposite direction for causing re-engagement of the catch.

4. The combination, with the reciprocating tool, of the reciprocating core carrying the same, aseries of coils put successively into and out of action to produce movement of the core in one direction, and a circuit-changer for shifting the current from the set of said coils acting at the end of thel stroke to a set of coils previously thrown ont of action, whereby the latter set, which were instrumental in moving said core in a given direction, may now act to move said core in the opposite direction.

5. The combination, withy a reciprocating tool, of an electro-magnet tending to oppose the movement of the tool at or near the end of its stroke, so as to act as a cushioning device.

6. The combination, with the reciprocating core, of ay checking or cushioning coil or set of coils in circuit near the end of the stroke and IIO located in position to oppose thepassage of .the core through them.

7. The combination, with a reciprocating tool and core connected therewith, of a magnet-coil for acting on the core at or near the end of its stroke and means for closing the circuit of said coil, as described, whereby the latter shall exercise aretarding or cushioning tendency.

8. The combination, with a reciprocating tool, of an operating magnet-core, a series of coils, a commutator for maintaining a group of said coils in circuit in advance of the core, and means for causing a shifting of the coinmutator by the inertia of a part moving with the tool, whereby the point at which the advance of the group of coils in action ceases is independent of the length of stroke.

9. The combination, with the reciprocating core, of the commutating device moving therewith, an interposed spring in which the energy of the stroke in one direction is stored, a catch for locking the commutating device against movement by the action of the spring during thestroke in the opposite direction,and means for unlocking the catch at the termination of the latter stroke.

10. The combination, with the series of coils and the reciprocating support, and the commutating device movable thereon, of an interposed spring and a catch for locking the device toits support, whereby the support may move independently of the commutating device and against the action of the spring at the end of the stroke in one direction, while at the end of the stroke in the opposite direction the commutating device may move independently of the supporton being released from the catch.

11. rIhe combination, with the reciprocating core and the series of actuating-coils, of a set of contact-springs normally adapted to form a continuous closed circuit `independent of the coils, coil-terminals normally open-circuited,

, and means for interrupting the continuous closed circuit at the proper points and connecting an open-circuit terminal of a core thereto, as and for the purpose described.

12. The combination, with the reciprocating core and the series of coils operating on the same, of a set of contact springs and stops connected in a continuous circuit, connections from one terminal of the coils to the continuous circuit at points between springs and stops, and connections from the other terminals of the coils to springs normally ont of contact with the firstsnamed springs, as and for the purpose described.

13. The combination, with the series of coils and the contact springs and stops in a continnous or series connection with one another, of

supplemental springs connected, respectively, to the coil-terminals and reciprocating rods or pins for forcing the latter springs into contact with the former, so as to break the continuons or series connection, and at the same time to put the corresponding coil into circuit.

14. The combination, with the reciprocating core and the series of coils acting on the same, of reciprocating pins F and connecting devices on the outside of the coils for throwing the same into circuit, said connecting devices being controlled 'by the reciprocating pins, as and for the purpose described.

15. The combination, with the reciprocating core, of the cam projection a, moving there with, and the pins F, extending to the outside of the coils and operating upon suitable contact-springs connected to the coils and to the circuit for throwing the coils into and ont of circuit with a suitable source of electricity.

16. The combination, substantially as described, of a rod or, spindle connected to the drill-tool, a collar carried thereby and having a screw-connection therewith, as described, a spring, M, for moving the collar on the spindle, and a stop for engaging the collar and holding the same stationary, so that when the spindle moves independently ofthe collar the tool will be turned.

17. The combination, with the spindle connected with the tool, of a collar or block, Ml, carried by the spindle, a spring, M, for moving the collar or block on the spindle, a stop, N, for holding the collar from rotation at the end ofthe stroke, and a connection between said collar and spindle, as described, whereby the longitudinal movement ofthe spindle through the collar will cause said spindle to rotate.

18. The combination, in a drill, of spindle L, collar M2, capable of movement thereon, as described, a stop carried by the spindle for limiting the longitudinal movement ofthe collar, and astop, N, with which the collar engages on the reverse movement ofthe tool, said stop being roughened or serrated for holding the collar from rotation, so that as the spindle moves the latter will be turned.

19. The combination,with the reciprocating core and a series of coils operating thereon, ot a series of pins raised in succession by the core or a part carried thereby, and spring-con tacts opened and closed in turn by said pins, as and 4for the purpose set t'orth.

Signed at Syracuse, in the county of Onondaga and State of New York, this 19th day o1' June, A. D. 1886.

HARRY NORTON MARVIN.

lVitncsses:

WILLIAM J. GILLnrr, J. E. Wenns.

ICO

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