US2095213A - Metronome - Google Patents

Description

Oct. 5, 1937.

A. M. ENGLISH METRONOME Filed July 20, 1934 3 Sheets-Sheet l lll II B27/aldo M E Oct. 5, 1937.

A. M. ENGLISH METRONOME Filed July 20, 1934 3 Sheets-Sheet 2 Oct. 5, 1937. A. M. ENGLISH METRONOME Filed July 20, 1954 3 Sheets-Sheet 5 ofzmzdoMEngs Patented Oct. 5, 1937 UNITED STATES PATENT OFFICE METRONOME Application July 20, 1934, Serial No. 736,229

4 Claims.

This invention relates to mechanism for prcducing reciprocating swinging motion, either silent or audible, and more particularly to an improved and novel form of metronome for stu- 5 dents of music, and it has, among others, the

advantages and novel features hereinafter described and illustrated in the drawings.

In the drawings of one embodiment of my invention selected for illustration and description i@ herein:

Fig. 1 is a front elevation;

Fig. 2, a plan or top view, with the casing removed;

Fig. 3, a side elevation from the left;

Fig. 4, a side elevation from the right;

Fig. 5, a perpendicular detail section on the line 5 5, Fig. 7, from the right, showing certain elements in elevation and enlarged;

Fig. 6, a front elevation with the dial face removed;

Fig. 7, a horizontal partial section on the line 'I-l, Fig. 6, looking down, showing parts in full lines;

Fig. 8, a partial section and elevation on the 5 line 8 8, Fig. 3, looking toward the rear of the dial face;

Fig. 9, a bottom end view showing also the parts sho-Wn in Fig. 8;

Fig. 10, a vertical section on the line itl-i0, Fg- 3;

Fig. 11, a vertical, partial section on the line II-II, Fig. 8, from the right on an enlarged scale;

Fig. 12, a similar view, with certain elements in different positions;

Fig. 13 is a detail section on line I3-I3 of Fig. 6;

Fig. 14, a similar detail section on line III-I4 of Fig. 6;

Fig. 15 is a front elevation, Without the case, of a modified form of construction;

Fig. 16 is a front view of the same, with the front plate removed, but dotted in for convenience;

Fig. 1'7, a side elevation from the left, corresponding to Fig. 3, with a few elements, not changed, omitted, for convenience;

Fig. 18, a horizontal, partial section, on the line I8-I8, Fig. 17, and corresponding substantially to Fig. 7;

` Figs. 19, 20, 21, 22 are, respectively, detail views of a modified form of construction of the variable, selective, tick-making ratchets and hammer;

Fig. 23, a longitudinal, vertical section through the sleeve carrying the tick-making ratchets with the driving gear and tick gears thereon;

Fig. 24, a horizontal, partial section on the line 24-24 of Fig. 16, showing the electively usable l tick-producing lever.

Referring first to Figs. 1-4, my novel metronome comprises .a frame comprising a front plate I the lower half of which may be offset inwardly for convenience, rear plate 2, connected and supported by a plurality of, herein four, corner bars or posts 3. At each corner of the plate I is a laterally extended post 5, upon the outer end of which is carried a dial face 6, and held in position by screws l in the posts.

Upon the dial face, Fig. 1, and arranged in circular form, are a series of suitable characters, as groups of numerals A, each group indicating the number of oscillations or beats per minute at which a pointer or time beating baton 8 may be set to operate, and corresponding to the tempo of various musical compositions. The pointer 8 may be of any desired color, and its outer end may be of any contrasting color, if preferred, as by slipping a short sheath B of the desired color over the end. Rotatable upon a stub shaft I0, extended through the dial face, is a beat identifier 9, of arrow or any other suitable shape, which points to and identifies the frequency, for instance, 80 beats a. minute, with which the member 8 is operating.

This indentifier, Figs. 1-4 and 6, is mounted upon the hub of a speed changing pulley Il, carried by the stub shaft I0 in the plate I, and is rotated and adjusted by means of a belt spring I2 running over the pulley II to a speed controlling hub or knob-carrying pulley I3, Figs. 3, 4, 6, mounted upon the outer face of an arm I4 on the front plate I, and the knurled hub i5 of Which Fig. 11, is extended through an opening in the dial plate 6, and thus conveniently accessible.

The driving mechanism may comprise, in part, any suitable clock motion construction, and herein includes, Figs. 2, 3, 4, dotted lines, a coiled spring I6, the inner end being secured to the plate 2, While the outer end drives a shaft Il through the housing I8 and gear I9, carrying said housing and fixed to the threaded shaft I'l 4mounted in the plates I and 2. The spring I6 is secured to the shaft I1 within a housing I8, which, in turn, is carried by a driving gear I9 on the shaft I1.

For winding up the spring I6, Figs. 3, 7, and 9, there is provided a short horizontal shaft 2l, mounted in an elongated bearing 22 on the rear 23, in engagement with the gear I9, Yand by v which the latter and the housing I8 thereon are rotated, and the spring I therein Wound.

Adjacent the shaft 2I, Fig. 9, and on a shaft 25 mounted in the plates I, 2, is an elongated hub 26, carrying two pinions, a rear one, Z'I, also in mesh with the gear I9, and by which the hub 26 and pinion Zare rotated, and a forward one, 28, engaged by a pawl 35 on thejface of a gear 3i, also on the shaft .1.

When the shaft 2i is rotated for Vwinding the spring I the hub 26 is rotated freely Vthrough the pinion 2 by the gear I9 and yielding action of the pawl on the gear 3I, engaging the pinion 28. Y Y

The gear 3i, Figs. 7, 9, also mesheswith a piniojn 33 on a shaft 35 mounted in the plates I, 2,

and the pinion 53 is fast at one end to a gear V35 also on the shaft 34.V

This gear '35 meshes with a pinion S'fast on one part 35 of a two-part shaft, slidable axially in a hollow section 3S thereof, mounted in ball bearings i5-4I on the plates I, 2, respectively, the pinion 3l having fast thereto at one enda governor driving gear 42.V

The shaft. section 39 carries a coil spring 44, which is seated against a collar i5 on that section, and against the pinion 3l on the section 38, and acts to maintain said shaft and a driving disk 46 on the inner end thereof under sufficient pressure for a purpose to be explained presently. n tins instance, the pinion 3l, Fig. 5, is fastened to the shaft 38 by a key lll'seated in a keyway i8 in thepinion and akeyway in the shaft, not shown. l

Mounted for rotation in a bearing 5I on one edge of the front plate I, Figs. 7, 16, 17, 13, and a bearing in an'arm 52, Figs. 4; 16, 18, secured to the arm't, Fig. 6, on the arm I. pivoted on said plate, 'is a cam-shaft 55 carrying a cam driving roll 55 with a path 5i, in which rides a ro11'58 on a short arm 55, Fig. 6, on a hollow shaft 50 rotatable on the short horizontal post 6I. This shaft 65 is extended through the dial plate 6, Fig. 1,-and carries the pointer or baton 3 adjacent the dial face already described. Y

The shaft 55, Fig. 7, also carries a driving roll 63 splined thereon, and with a channel or race 54 in the roll face, and in which' rides a roll 65,

also shown in dotted lines in Fig. 6, onia rollad- Y justing'lever 66 witha hub 6l onits upper end, by which it is pivoted to the plate Iby a post 68.

The ange l@ ofthe roll 53 is maintained in frictional contact with the face of the disk 46 by the spring 44 on the shaft 38 aboveY described, and thus rotation of the shaft 55, roll 63 and cam 56 is eected fromthe spring I5 ,through the gears I9, 2, 23, 3l, 33, 35, 3l, 42, 46 and 15.

The pulley I I, Figs. 3, 4, carries atits inner end a cam'ilange il, which bears against a roll 'I2 on the end of arcam lever "I3, pivoted at its upper end on the'hub' 67 of the lever 66, and lockable adjustably to the lever 56 by a set'screw 'I4 thereon, and extended through an elongated aperture '145 in the lever 73, so that when-the pulley I3 is rotated by the hub I5 on the dial plate, and belt spring I 2, the cam 'II,in contact with the rollV l2 on the cam lever 13 on lever 66 will move the roll 63 toward or from the center of the kdisk 45, and thus increase or decrease the radius of the path of travel of the flange of the roll 63, and

gated slot "M4 in the lever it, dotted lines Figs.

6, 14, the position of the lever i3 relative tothe lever may be adjusted on its pivot 6i, andthe position of the lever 66 whenengaged by the cam l Irchanged, also the throw of the lever 73 and the position of the roll 63 on the disk l5 changed, and the'oircumferential path'of travel Vofthe roll 63, and its speed increased or decreased, and thefrequency of the beat of the pointer 8 increased or decreased.V The hub 6l of the lever 56 and the lever 'I3 are locked to the studor post 53 by a VpinY 16, and the roll 'l2-kept in contact with cam flange 'II by the spring 722. The foregoing elements, as described beginning on page 5, line l,

together with the driving shaft 55 and connections to the baton, constitute a beat-frequency Ydetermining means, which by the adjustment ofV certain elements as described, enables the frequency of the beats of the baton to be changed at will by the adjustment of the disk 'II- on the pulleyV I I, by means of the pulley I5.

To govern the speed of the spring motor, Fig. 10, and effect substantially even action thereof and the pointer 3, a governor, of the iiy ball or any desired type, may be provided, and 'such is shown herein, Figs. 4, l0, mounted in a plate "E8 at the top of the frame, Fig. 2, and at the bottom in a plate "I9, inwardly extended fromV the plate I,

' where its shaft 55 is shown with a worm thread 6I thereon, and meshingwith the spiral governor gear 42. A brake shoe, Figs. 4,v 10, for the governor is shown as a block 8?., slidable on a pin 83 n the plate 78, with a coiled spring 84 thereon acting to resiliently hold the block in the position determined by the movement of an adjusting Yscrew 85 in the plate 778, the screw being threaded Y it rises with the increased speed of the shaft 80,

and reduce'the speed of the mechanlsm,when the desired 11min is attained. Y

To initially adjust the baton beats, the regulator is adjustedV so that the disk i5 will make 7G revolutions per minute with the spring about one-half wound. Then, with the indicator at and'spring one-half woundturn stud l5 until the baton makes 40 beats per minute, and the rest ofthe scale will be correct.

Obviously, after a continued period of operation of the metronome, the spring may lose a little of its force, which mayv result in a slight unevenness of motion and throw of the pointer 8.

To avoid this difficulty, it seins best to limit theA initial period ofY operation from one winding to Y such time as the operation will be substantially uniform, this period in turn being dependent of course upon the strength of the spring.

To that end, I have provided an automatic stop -member for the purpose. On an overhanging support 81, Figs. 2, 10, at the top of the plate I, there is pivoted by a pin 88 a pawl 89, which is normally pressed with frictional contact against the face of the gear I9 by a spring 90 coiled about the pin 88, the opposite ends of the spring being seated respectively against the edge of the support 81, and the face of an arm 9| downwardly extended from the pawl. To determine the time, however, when thepawl shall act, the arm 9|, Fig. 10, is extended downward far enough to receive between two ears 92 on its lower end the upwardly extended spur 93 on a double collar 94,Figs. 2, 3, threaded on the screw I1, and which collar automatically travels forwardly on the screw I1 as the spring is wound up, and then similarly travels rearwardly as the spring unwinds and the gear I9 rotates in the opposite direction to automatically operate the device. The above described mechanism is proportioned and adjusted to cause the pawl 89 to swing laterally and to drop into a slot 95 on the face of the gear I9, Fig. 10, at the desired time: preferably, in the present instance, about thirty-ve minutes.

A manually operative stop or brake device is also provided. Upon the face of the dial plate 6, Fig. l, near the lower right-hand corner, there is pivoted on a pin 96 an arm 91, with the supporting sleeve 98 for the pin, Figs. 6 and 8, on the rear face of the plate, the pin carrying an arm 9S on its inner end and seated on the sleeve end, the arm having a laterally-turned end or shoe |00, and an upwardly-turned finger |I, the former adapted, when the arm 91 is swung upward, to engage the lower face of the disk 46, Fig. 6, and the finger |0I, to engage the edge of the disk, to stop the mechanism. Swinging the arm 91 downward, of course, releases the stop device.

Some students cannot use a metronome with an audible beat or tick of the pointer, as it confuses them, while others find the audible beat either as a signalling of the baton beat or as supplemental thereto, a great help, and sometimes it is a necessity for best results. There is a full, complete and beneficial cooperation between the baton beat and the signallizing of the same to the player. The baton beat is important, but if not seen, it is of no advantage, and unless its movement is signified to the player, its advantage may be lost entirely. Accordingly, while the baton beat may be effective when its movement should be indicated by an audible signal to that effect, to guard against possible oversight by the player, I have provided an optional, audible beat signalling device for use when desired.

Even though the student is relying upon the visible beat of the baton for guidance, his eye may stray away momentarily, and then, without assistance, he would miss the beat of the baton. In such case, the audible tick which signalizes each beat of the baton informs him that the movement of the baton is effected, and, cooperating with the movement of the baton, brings to the student the signal ofthe beat which he missed seeing, and enables him to continue his playing in time with the action of the baton.

Near the lower edge of the dial face 6, Figs. 1, 11, 12, is an inwardly extended pin |02, Fig. 8, and adjacent the same is a similarly positioned tick controlling screw |03 With Va knurled head |04, Fig. `1. On the rear face of the plate 6,

both screw and pin extend through the lower end of a tapper or tick member |85, and a plate |06, thereby holding them in position, and the latter has upon its upper end a cam or tooth engaging arm |01 to engage the cams |88 on the shaft 55, Figs. 8, 1l, just behind the dial plate 6, while the tapper is provided on one face with a small metal boss or head |09. The screw |03 carries a threaded spacing block IIO, which also is slidable on the pin |02, and, resting against the block I0 is one end, Fig. 8, of a U-shaped spring III, the opposite end of which is seated against the lower end of the plate |06. This spring III acts to maintain the block ||0 steady in an adjusted position adjacent the outer ends of the pin |02 and screw |03. To retain the screw |83 in proper position, Fig. 8, and act as a bearing for the outer end. of the same, there is provided a yoke member II3, one end of which is seated againsta block I I4 on the inner end of the screw |83, and is drilled to receive the screw |03 and pin |02, while the opposite and outer end, narrowed, receives only the screw |03.

Normally, the arm |01 does not contact with the teeth |08, but, by turning up on the screw |03 and causing the block III! to be fed inward toward the block ||4 on the screw |93, and thus to feed forward and compress the spring upon the plate |08, the arm |01 will be brought into position where it will be engaged and put under tension by the cams |08 as they rotate, and as the arm slips from each cam during rotation of the shaft 55, the spring III will cause the ticker or tapper |09 to strike the dial plate with sufficient force to be heard either faintly or plainly, according to the degree of tension imposed upon the tapper by the spring I I I to signal to the player the completion of the baton beat to enable him, in case he did not or could not see the baton, to maintain time correctly. Obviously, by omitting one of the cams |88, the tapper |09 will be actuated only by every other beat of the pointer 8, and by increasing the number of the cams, more frequent taps may be heard. This, of course, would necessitate certain changes in size, number and proportion of several of the elements producing and controlling the ticks. A modified form of construction for producing an elective number of ticks is described later on.

To prevent any ticking or tapping action, if desired, a silencing device is provided and cornu prises, Fig. 8, an arm ||5 pivoted to the rear of the dial face at IIS, and actuated by the arm |I1 on the dial face, Fig. l, to be moved beneath the tapper |89, Figs. 8, 11 and 12, so that the tapper will not strike the dial plate even though the spring adjustment would otherwise cause it to do so. A spring member I I8 on the pivot IIIS, Fig. 8, maintains sufficient frictional contact with the rear face of the dial plate to cause the lever II5 to remain in adjusted position.

The element of timing which so generally enters into all human activities is notably important in the expression of the art of music.

There is, of necessity, among musicians a recognized standard of the rates of timing, and it was long ago discovered that a mechanical device of some sort was necessary for standardization.

In training students to become musicians, it is necessary to employ some expression of timing, so that those with whom the sense of timing is weak may have a model to which they may conform, and so be corrected and their timing sense developed.

quency means shown in Figs. 15-24 may be de- The conventional Maezel metronome in general use, has, to some degree only, met the requirement. Its continued use is a Anerve-racking strain, and to sensitive ears unbearable, and greatly limits its use.

It is a carefully balanced device, like a clock, and if rit does not stand eXactlylevel,V the tick becomes uneven, and it becomes useless, Yand may even stop. To change and vary the tempo, it is necessary to stop vthe metronome and wait an appreciable vtime for the tick to again become even. The object of the present device is to provide a metronome that will more fully meet all requirements.V

VThe beatwor tick 4is silent, unless preferred otherwise, and is thus comprehended by the eye, as in the case of a Vconductor of an orchestra. The'student does not need to listen to the tick,

unless he wishes to, and if Yhe does, it can beV adjusted to give him an audible beat or tick instantly to signal the end of-the baton beat, without stopping the device, and it will be Vof the loudness he wishes, to be heardthrcughout a large room, or scarcely audible.

The teacher maybe relieved of the strain of counting aloud, or beating audibly, and cease to be the mechanical model V*with which some pupils must be provided.

YTo vary the tempo, it is not necessary to stop the device, and it need not stand perfectly level. The improved device is compact in construction, readily carried in the hand or packed in a bag, or even a large music case if desired. Furthermore, there is need of practice by the student at times in the use of a fractional part or por- .tion of the baton beats, that is, counting and marking time by every other beat, or every third, or other fractional proportion of the baton beats, and in such work, the ticker signal is a most important element forsignalling to the player the proportional part of the baton beats that is to guide him in his playing.

In Figs. 15 to 24 are illustrated certain modications in the foregoing describedconstruction,

s designed to provide a selective beat signalling tick frequency'means relative to the baton beat frequency. In such case, the frame, Fig. 17, with its front plate and rear `plate 2, suitably connected are the same. The dial is practically the same; except that the tick controlling means, including the arm it! has a graduatedV degree of adjustment to be described.

In this modification, part of the described winding mechanism is omitted, and the spring i6, secured to the shaft ll Vand housing I8, is wound outward from the shaft Il, and notinward from the housing I8, as in the former case. The spring It, Fig. 17, is wound by means of a suitable key, not shown, which is inserted in the outer end of the hollow shaft |26, carried by the plate 2 and a gearrhousing 12| on said plate,

the shaft carrying a pinion |22 meshing with aV winding gear |23, these features causing the spring operated mechanismgto operate in the reerse direction from that shown in Fig. 3.

The modified form of tick producing and fresoribed as follows:

In Figs. 16, 18, the left-hand end of the cam drive shaft 55, mounted in bearing I, has no cams It as in the case of Figs. 6, 7, 8, but carries, a pinion |211, in mesh with and driving a gearA |25, on a ratchet shaft |25 inbearing |21 on modified plate5l, and new bearing |28 on Vthe plate l. The pinion |24 has 8 teeth, and the gear |25 has Li8 teeth, so that the former makes 6 revolutions to l of the latter. The shaft |26, Figs. 16 and 18, carries a Vsleeve |29, splined thereon, which, in turn, carries a series of four tick producing ratchet wheels: |39, Fig. 19, on which the teeth are of equal length; |3|, Fig. 20, wherein every other tooth |32 is a long one; |33, Fig. 21, in which every third tooth |34 isa long one; and Fig. 22, |35, Yin which every fourth tooth |36 is a long one.

On the sleeve |29 and adjacent the gear |30, Figs. 16, 18, is a ratchet-shifting collar |31, with a groove |38 in its edge to receive the upper, inturned end of an arm |39l on the inner end of a stud |49, extended through the dial face, Figs. 16, '18, and operated by a lever IM, corresponding in function in part to the screw |03 in Figs. 11, 12. By means of this arm and the construction described, a ratchet selected, to give the vbaton beat signal of desired frequency, can be moved Ywith the sleeve |29 on the shaft 55 to the right to operative position relative to a ticker, or hammer to be described.

Just above the stub shaft lili), Figs. 16, 18, the inner plate H52 in this construction, adjacent the dial plate 6, is provided with a parallel plate |93, with an inturned lip 1M 'on its lower end, having notches |45 therein to receive the upper end of the armv |39 and lock it and the selected ratchet in position relative to the hammer to be described. Adjacent the ratchet |39, Fig. 16, and below the stub shaft |39, the inner plate EQ2 has struck inward from it a horizontal rib with a depressed central edge section with a knife edge |41, dotted lines Figs. 16, 24.V The opposite end sections of this lip, Fig. 24,V are extended slightly further inwardly from the main rib, to provide two narrow lips Mt, which are adapted to receive, Fig. 16,V in hinge-like manner two notchesv 'i9 on the opposite edges of the lower end of an Vupwardly extended hammer |59.

The upper edge of each notch rests upon the lips |48, and the hammer rests'and moves upon the knife edge `|117 to reduce the friction. The Vhammer |50, Figs.' 16, 19 to 22,-has a suitable head |5l, as steel.

The hammer also has an arm |52, extended forwardly in position to engage the long teeth of the selected ratchet positioned in turn by the lever |i|| and arm |39 to produce the desired tick.

To impose suicient tensionY upon the hammer |59 to cause it to hit the plate |122 and make a loud signal tick when the arm |52 slips from a long tooth on any ratchet, Fig. 24, a stud |53 with an arm |54 thereon is provided on the dial face to operate the stud to desired position, and corresponding substantially to the function of the elements |93, Fig. l. On theinner end of the shaft 53,V Figs. 16, 24, is carried a spring |55, corresponding in function to spring Figs. 8, l1, 12, which lies normally against the hammer below the rib or knife edge |47, and near the VVhammer' end, and consequently imposes no operating pressure upo'nthe hammer action, and no tick signalY of the baton beat is produced under these conditions when the arm |52 slips from a Ylong tooth on either ratchet. If, however, Fig. 16,

the arm |513 is swung upward, and the spring |55 caused to bear upon the hammer |59 above the lips H18, then the hammer will be under compression, and, when released by a long tooth, will strike theV spring |55 engages the hammer relatively high above the lips |48, the hammer will produce a louder tick signal of the baton beat when released by the ratchet than if it engaged the hammer o-nly slightly above the lips |48.

Further, the hammer may be so adjusted that it will produce a slight tick signal of the baton beat when released from the short teeth on the ratchet and a loud tick when released from the long teeth. Or this result can be effected by properly proportioning the length of the short teeth.

The foregoing modified construction, therefore, provides a loud tick signal for every beat of the baton, or every other beat, or every third beat, or every fourth beat, as elected by the operator at the end of its oscillatory movement.

Many detailed modifications of the foregoing construction can be made, all Within the spirit of my invention and scope of the appended claims.

I claim:

1. A metronome comprising a frame, a dial face thereon, a time beating baton mounted for oscillation across the dial face, and means for effecting the oscillations including a motor, a driving shaft, a cam thereon, a roll therein on the baton end, a train of gears connecting said motor with the driving shaft including a driving disk, and a driving roll on the shaft operatively contacting with the disk.

2. A metronome comprising a frame with a dial face, speed indicating characters on the dial, a time-beating baton mounted to oscillate across the dial, and means for operating the baton comprising a motor, a cam driving shaft with a driving cam thereon, having a race therein, a roll in said cam race and on the baton end; a train of gears connecting the motor with the driving shaft and including a driving disk, a driving roller on the shaft and operatively contacting the disk; the last-mentioned roller also having a race therein, and a cam lever carrying a roll in said race, and means having an adjustable cam engaging said cam lever to effect adjustment of the speed of the driving disk and baton beat, said cam adjusting member acting also to register said adjustment with the beat indicating characters.

3. A device of the class described comprising a frame with a dial face having speed indicating characters thereon, a time-beating baton mounted to oscillate across the dial, and means for operating the baton, comprising a motor, a driving shaft with a driving cam thereon, a cam roll in said driving cam and on the baton end; a train of gears connecting the motor with the driving shaft and including a driving disk, a driving roller on said shaft With a race therein and operatively contacting the disk; and means for adjusting the speed of the baton beat and registering the same with the speed indicating characters comprising a speed changing pulley on the frame, with a speed identifying member thereon cooperating with the indicating characters, a control pulley connected with the speed changing Pulley, a cam on the speed changing pulley, a cam lever adjustable by said cam and carrying a roll in said driving roller, to position the driving roller on the disk and thereby determine the speed of the baton beats and cause the speed identifying member to point to the proper speed indicating characters; additional adjusting means for and on the cam lever; a governor for said drivinLT means, and a stop device comprising a brake member mounted on the frame and operable from the dial to engage the driving disk to stop it.

4. A device of the class described comprising a frame with a dial face having speed indicating characters thereon, a time-beating baton mounted to oscillate across the dial, and means for operating the baton,- comprising a motor, a driving shaft with a driving cam thereon, a cam roll in said driving cam andon the baton end; a train of gears connecting the motor with the driving shaft and including a driving disk, a driving roller on said shaft with a race therein and operatively contacting the disk; and means for adjusting the speed of the baton beat and registering the same with the speed indicating characters and comprising a speed changing pulley on the frame, with a speed identifying member thereon cooperating with the indicating characters, a control pulley connected with the speed changing pulley, a cam on the speed changing pulley, a cam lever adjustable by said cam and carrying a roll in said driving roller, to position the driving roller on the disk and thereby determine the speed of the baton beats and cause the speed identifying member to point to the proper speed indicating characters; additional adjusting means on the cam lever comprising a pivoted arm movable over and adjustable on said cam lever relative to said cam on the speed-changing pulley, and means for holding said cam lever in contact with the speedchanging pulley cam.

ANALDO M. ENGLISH.

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