US742038A - Range-finder. - Google Patents

Description

' No. 742,038. PATENTED 00120. 1903*. J. W. KERN, DEGD.

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J. W KERN, DEGD S. M. KERN, ADMINISTRATBIX.

PATENTED OCT. 20, 1903.

RANGE FINDER.

APPLICATION FILED MAY 16, 1901.

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No. 742,038. PATENTED OCT. 20,1903

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RANGE FINDER.

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UNiTED STATES Patented October 20, 1903.

PATENT OFFICE.

SAR-ATH M. KERN, or PORTLAND, OREGON, ADMINISTRATRIX or JOHN W.

- KERN, DECEASED.

RANGE-Fl NbEFlt' SPECIFICATION forming part of Letters Patent N 0. 742,038, dated October 20, 1903.

I Application filed May 16, 1901.

To a whom, it may concern:

Be it known that I, SARAH M. KERN, a citizen of the United States, residing at Port land, in the county of Multnornah and State 3 of Oregon, am' the administratrix of the estate of JOHN W. KERN, deceased, late a citizen of the United States, who invented certain new and useful Improvements in Range- Finders; and I do hereby declare the follow-' ing to be a full, clear, and exact description of-the invention, such as will enable others skilled in the art to which it appertains to for multiplying the distance traversed by the movable end of the movable telescope it would '65 notbe possible to determine accurately by the slight movement of the pointer the distance make and use the same.

The invention has for its object to provide I5 simple and effective means whereby in a certain and ready manner to ascertain the distance of an object from the point, of observation or to locate a point at a desired distance from that of observation.

2o Briefly stated, the invention comprises two telescopes, one of which, at least, must be pivotally mounted to permit its being moved at an angle with relation to the second telescope in order that both telescopes may be focused upon a common distant object. Combined with the movable telescope and operatively connected therewith to receive movement therefrom is a hand or pointer adapted to be moved over the'graduated surface of a dis-' 3o tance-indicator, and the mechanism interme diate the distance-pointer and the movable telescope is so proportioned and arranged that when the pivoted telescope is moved from its initial position and brought to a focus upon a distant object previously brought within the focus of the stationary telescope the distance-pointer will be so moved from its initial position with relation to the pivoted telescope as instantaneously to indicate 40 upon the distance-dial the remoteness from.

the finder of theobject sighted.

In the one embodiment. of the invention shown a bed-plate carrying two telescopes is employed, one of the telescopes being rigidly fixed on the bed-plate and at-exact right angles to its base-line and the other normally parallel with the first-named telescope, but adapted for pivotal movement on the bed plate to permit adjustment to bring an ob- 5o ject seen through the fixed telescope into the range of the movable telescope, a graduated Serial No. 60,605. (No model.)

dial bearing distan ce-marks suitably arranged thereon,"a' pointer to traverse the dial, and

motion-transmitting mechanism connecting the movable telescope and the pointer, where- 5 5 by the movement of the movable telescope will actuate the pointer to indicate on the dial the distance of the range-finder from the object under observation.

The adjustment of the movable telescope 6o will of necessity be very slight in sighting objects at long rangesay from one to five miles-so that without the provision of means measured. To provide for this,suitable means are provided-in the present instance a micrometer-screw, which is operatively connected, respectively, with the movable telescope g'and with the pointer. The micrometer-screw referred to comprises two screws or worms on a single shaft or bar, the screw coacting with the movable telescope having, say, one hundred threads to the inch and that coact ing with the pointer ten threads to the inch.

Thus a movement of the telescope through the arc of a circle of one one-hundredth of an inch will cause movement of the pointer 8c through an arc of a circle of several inches,

thereby permitting'the distance-marks onthe .dial to be widely spaced apart, and thus rendered easy to read.

In combination with the base-plate there may be suitable mechanism for elevating, depressing, and rocking the plate laterally and longitudinally and in addition a tangent-screw, by which arrangement the device will be adapted for use as a transit or surveyors instrument in running 0 lines, determining distances, or for other purposes in which the ordinary theodolite is employed. When used as a transit or theodolite, a suit-able tripod will be provided, and, if desired, a compass may be combined with 5 the bed-plate,

When used as a range-finder pure and simple, the elevating, depressing, and tilting mechanism mentioned and hereinafter to be fully described is suitable when the instrn- 10ov ment is employed in connection with military operationsthat is, for finding the range for artillery upon the land. When, however, the finder is to be used at sea, the motion of the vessel renders that mechanism inefficient, so that the same ora part thereof may be dispensed with and the base-plate supported upon a swinging or universal joint and be so counterweighted as to remain constantly in a level position irrespective of the rolling or pitching of the vessel. One finder may be provided for a group of guns upon the ship, or, if preferred, each gun may be furnished with a separate finder. In the latter instance the finder may be mounted upon the turret or carriage of the gun, with the fixed telescope pointed in a direction exactly parallel with the line of fire, so that when that telescope is focused upon the object and the range has been determined by means of the movable telescope and its attendant mechanism it will only be necessary to elevate the barrel of the gun in order to give the desired trajectory to the projectile.

One of the important advantages of this invention is that by providing a bed-plate or other support with two telescopes, each mounted on the bed-plate or support and arranged in sufficient proximity to each other to permit of being rapidly operated by a single operator, the transmission of telephonic signals or audible signals, such as are usually necessary in the employment of rangefinders now in use, is obviated.

Before proceeding with the description of the device it may be noted at this point that in the practical application of the principles embodied in this invention to a working machine the known ratios of expansion and contraction between different metals employed in its construction will be observed, so that errors in calculation which might arise were the knowledge of these ratios not observed will be prevented.

In the accompanying drawings, forming a part of this specification, and in which like letters of reference indicate corresponding parts, there is illustrated a form of embodiment of the invention in which it is shown as adapted for use as a range-finder for vessels and also for surveying purposes, it being understood that the same ideas may be carried into effect in connection with other forms of device without departing from the spirit of the same.

In the drawings, Figure l is a view in plan of a device when used either as a transit or as a range-finder, exhibiting the bed-plate, indicating-dial, and telescopes. Fig. 2 is a similar view with the dial removed, exhibiting the mechanism by which motion -may be imparted to the pointer. Fig. 3 is a view in elevation taken from the right-hand side of the machine and looking in the direction of the arrow 1 in Fig. 2. Fig. 4 is a view in elevation looking in the direction of the arrow 2, Fig. 2. Fig. 5 is a view in elevation of a part of the device looking in the direction of the arrow 3, Fig. 2. Fig. 6 is a horizontal sectional view of the elevating, depressing, and swinging mechanism, taken on the line 4 4, Fig. 5. Fig. 7 is a sectional detail view of a tangent-screw by which fine adjustment of the bed-plate may be effected in the running of lines or the like.

Referring to the drawings, A designates generally the bed-plate, which may, as shown, be an open-work structure made of any suitable material, such as iron, aluminium, brass, or any other material suited to the purpose. This bed-plate may be mounted in any suitable position for operation, as upon the carriage of a gun or in the port-hole of a vessel or upon a tripod, the latter being employed where the device is used for surveying puroses.

While the device herein shown is not exhibited as associated with a compass, it is to be understood that the same may be employed where the device will be used for running lines in landwork.

The bed-plate A is provided on its upper surface with two levels a a arranged at right angles to each other, these being used when the device is employed for surveying purposes and may, if desired, be omitted when the device is used as a range-finder, as it will be obvious that anyleveling of the deviceindependent of the vessel will be impracticable on the high seas. Upon the u pper side of the bed-plate are mounted two telescopes B and B the telescope B being rigid with relation to the bed-plate and arranged exactly at right angles to its base-line or rear edge and the telescope 13 being mounted for pivotal movement at its front end upon the bed-plate and being moved at its rear end through mechanism hereinafter to be described. The telescopes are, as usual, provided with suitable cross-wires by which to center an object and with adjustable lens, as will be understood. Adjacent to the fixed telescopeB and in line with each other are arranged two standards or initial direction-finders I), each comprising a rod of metal having its upper end polished or burnished, by which to present an object readily attractive to the eye.

Each of the telescopes B and B is supported upon a suitable casting b this casting in the case of the movable telescope B being pivotally secured at its forward end to the bedplate or casting A. The rear end of the casting of telescope B is provided with a bearing 11 comprising a frame b and a pivoted block b capable of swinging laterally and formed with a threaded opening adapted to be engaged by the threads on one end of a rod 1). Mounted also upon the bed-plate and between the telescopes, preferably in close proximity to the movable telescope B is a circular casing D, having a dial (Z laid off in requisite divisions, as feet, yards, and miles, these being arranged upon a series of concentric circles, as shown in Fig. 1. Pivotally mounted upon the side of the casing or upon the bed-plate immediately adjacent thereto is a sector-wheel 0, having a long arm 0 extendingwithin the casing'and a short arm without the casing, the latter arm being provided with a toothed edge 0, these teeth being engaged by a wormgear upon the rod 19 Mounted centrally within the casing is a pointer or hand d carried by the shank of the pinion d mounted in bearings 61 beneath the dial, the pinion being engaged by the toothed portion 0 of the long arm 0 of the sector-wheel. Theindicating-handofthepointer d is provided with an open portion d in which is secured a Wire d arranged radially to traverse the concentric'circles of the dial. The threads upon the rod b, engaging the bearing b will in this instance be one hundred to the inch, and the threads of the worm engaging the sector-teeth 0 will be, say, ten to the inch, and the relative lengths of the respective arms of the sector-wheel will be so proportioned that by the movement of the movable telescope a distance of one one-hundredth of an inch under the action of the twisting motion given to the rod 11 the pointer 61 will be caused to move through an are upon the dial of ten inches, by which multiplication of movement the reading of the measurements ascertained will be ren dered clear and easy. 7

To prevent backlash or any jarring of the hand or pointer d the pinion d meshes with a gear-wheel 01 the pivots of which are mounted in a suitable casting d also beneath the dial, a coiled spring d secured at one end to the supporting-plate of the wheel d as shown in dotted lines at d and at the other end of the stud of the wheel, serving to take up any lost motion or play that would exist between the teeth of the pinion d and the toothed sector 0, thereby causing the pointer 01 always to traverse the dial in a steady and regular manner.

As'shown in'Figpl, the dial is marked off into five concentric circles, which are divided 011' in divisions of feet, yards, and miles, as will be understood by reference to the said figure. The arm a of the sector 0 carries a vertical pin or pointer 0 which projects through a curved slot 0 in the dial, the wall of this slot being laid off in divisions from 1 to 6, these divisions corresponding to the circles on the dial. Initially or when an observation is to be taken the pointer 61 and 0 will point, respectively, at the zero-mark on the large dial and on the curved slot 0 When the pointer d is moved by the micrometer-screw through the arc of alarge circle, the pointer 0 will be moved through the arc of a smaller circle. The function of the pointer and its scale, which will be hereinafter referred to as a scale-indicator, is to determine which circle on the large dial is to be inspected to determine the reading. Thus,

for instance, ifthe small pointer is between 0 and 1 the reading will be found on the outer or first circle; if between 1 and 2 the reading will be on the second circle,

and it between 2 and 3 the reading will be on the third circle, and so on. In

practice all readings from a greater distance than twelve hundred feet will be found on the firstor outer circle.

The circular micrometer-head E, carried by the rod b, to which it is secured by the milled thumb-nut E',has its periphery marked 06 into a suitablenumber of divisions, preferably one hundred, as shown, to form a scale for reading the fraction of revolution of the rod'b. Secured by means of a bracket upon the bed-plate and cooperating with the micrometer-head E is a segmental scale e, forming a vernier and marked off in this instance into ten divisions, these tendivisions being exactly equal to nine of the divisions upon the micrometer-head E, thus permitting a reading to one-tenth of the latter divisions. When the pointer upon the large dial has been brought to the zero-point, the nut E is loosened to permit the head E to be turned upon the rod 12 in order to bring the zeropoint upon said head and upon the vernierscale into registry, when said nut is screwed down to secure the head to the rod and may then be used to turn the rod in finding the range.

The micrometer-threads being a distance of one one-hundredth of an inch apart, the scale E permitting a reading of one onehundredth of this distance and the vernierscale allowinga reading to one-tenth of a division of the scale E, it will be seen that the movement of the telescope B of one onehundred thousandth of an inch may be read,

so that the angular changes caused thereby while very small are easily read.

The object of the micrometer-head E and vernier-scale e is to locate a point at adesired distance from that of observationthat is to say, should it be desired to locate a point at one mile or farther from the operator this disk and scale will then come into use, the marks on the micrometer-head and vernierscale indicating the micrometerscrew reading. Thus should it be desired to locate'a point five miles distant, or eight thousand eight hundred yards on the dial, the screw will be moved until it indicates 21.96. Then by sighting the telescopes'to bring the cross-wires to bear upon a point at that'distance five miles will be located: If it be desired to locate a point, say, three miles distant, or five thousand two hundred and eighty yards on the dial, the screw will be moved untilitindicates 36.6. Then by sighting the telescopes to bring the cross-Wires to bear upon apoint at that distance three miles will be located. If it be desired to locate apoint, say, four thousand yards distant on the dial, the screw will be moved until it indicates 48.31. bring the cross-wires to bear upon a point at that distancefour thousand yards will be located. Secured to the under side of the bed-plate are brackets F,sh own provided witli Then by sighting the telescopes to journal-bearings supported on journals car ried by a standard f. The standard f is provided at its lower end with a ball f (shown in dotted lines in Fig. 5,) engaging a ballsocket G, carried by the base-support g. A four-arm spider g is supported on levelingscrews g having each their lower end provided with a ball engaging a ball-socket in the basesupport. The spider is mounted to turn on the standard, but is held from longitudinal movement thereon, as by shoulders on the standard. A collarf closely fits the standard f and carries a set-screw f for looking it thereto. A tangent-screwfflshown carried on the spider g engages said collar, thus providing precise means for adjusting the bed-plate in an arc about a vertical axis. To one of the brackets F is attached a graduated sector arranged to be traversed by the pointer carried by an arm a depending from the adjacent journal. The function of this sector and pointer is to determine when the bed-plateisapproximatelylevel. Anyfurther adjustment to secure a perfect leveling of the base-plate is effected through the leveling-screws above described. For rocking the bed-plate on its supporting-journals a toothsector a, depending from the bed-plate, is arranged in mesh with a worm f, journaled in a hanger f secured to one of the journals supporting the bed-plate and provided with an operating-crank f. For permitting the bed-plate to swing about a vertical axis the base-support g is rotatably carried in a frame g A'toothed sector f secured to the basesupport, is arranged in mesh with a wormf journaled on the frame g and provided with an operating-crankf By the mechanism just described adjustment of the bed-plate in every conceivable direction is provided for, so that the device, as before pointed out, will be adaptable for use either as a range-finder on vessels or for surveying purposes on land.

The operation of the device thus described when used as a range-finder in military operations upon the land is as follows: The frame g being mounted upon any suitable support-such as a tripod, for instance-the worm-gearf is manipulated,by means of a crank f", in order to bring the pointer carried by the arm a upon the zero-point of the scale f The bed-plate is then leveled by means of the leveling-screws g and the levels a ("6 the fixed telescope being pointed in the general direction of the object the range of which it is desired to ascertain. This fixed telescope is then pointed in a vertical line with said object by means of the coarse adjustment of the worm-gear f and if the object be not upon a plane with the instrument the wormgear f is manipulated until the proper pitch of the fixed telescope is obtained. The crosshairs in the telescope are then brought to bear exactly upon the object by means of the tangent-screw f. The movable telescope B is then manipulated, by means of the wheel carried by the rod 1), until its cross-hairs are also brought directly upon the object. At the same time with this movement of the movable telescope the sector-wheel O is operated to cause the pointer 61 to leave its zero position upon the dial 1) and travel therearound in the direction of the movement of the hands of a clock, and when the object has been focused upon the cross-hairs of the movable telescope the reading taken from the dial will give correctly the range of the object, these readings to be taken, as before explained, from the circle indicated by the position of the pin 0 in the slot 0 From this reading the elevation of the barrel of the gun may be calculated, at the same time taking into consideration the angle of depression or elevation of the telescopes as read upon the scale f When used as a surveyors instrument, the manipulation of the leveling means will be similar to that above described, and the method of locating a point at a given distance heretofore described may be employed.

\Vhen used upon shipboard as a rangefinder, either the positive leveling means or the gravitating and freely-swinging leveling means may be utilized, or one of such means may be substituted for the other to suit the prevailing conditions.

Having thus fully described the invention, what is claimed as new is- 1. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator, a rod journaled on said bed-plate and provided with threads of different pitch at its respective ends, and means operatively connecting said threaded ends to the movable sighting device and the indicator, substantially as described.

2. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator, a rod journaled on said bed-plate and provided with threads of different pitch at its respective ends, means operatively connecting said threaded ends to the movable sighting device and the indicator, and means for securing positive action and preventing backlash in the mechanism, substantially as described.

3. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator, a rod journaled on said bed-plate and provided with threads of different pitch at its respective ends, means operatively c011- necting said threaded ends to the movable sighting device and theindicator,andaspring' actuated Wheel arranged and constructed to secure positive action and prevent backlash in the mechanism, substantially as described.

4-. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator provided with a dial and pointer, a plurality of differently-graduated scales on said dial in position to be traversed by said pointer, an auxiliary pointer and auxiliary scale on the indicator, said auxiliary scale containing a number of divisions equal to the number of said dilferently-graduated scales, and so arranged that the position of the aux iliary pointer will determine the particular scale on which the reading of the indicatoris to be taken, and means operatively connecting the movable sighting device and the indicator, substantially as described.

5. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator provided with a dial and a pointer, a plurality of differently-graduated concentric circles on said dial in position to be traversed by said pointer, an auxiliary pointer and auxiliary scale on the indicator, said auxiliary scale containing a number of divisions equal to the number of said differently-graduated circles, and so arranged that the position of the auxiliary pointer will determine the particular graduated circle on which the reading of the indicator is to be taken, and means operatively connecting the movable sighting device and the indicator, substantially as described.

6. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator provided with a dial and pointer, a

plurality of ditterently-graduated concentric circles on said dial in position to be traversed by said pointer, an auxiliary pointer and auxiliary scale on the indicator, said auxiliary scale containing a number of divisions equal to the number of said differently-graduated circles, and so arranged that the position of the auxiliary pointer will determine the particular graduated circle on which the reading of the indicator is to be taken, means operatively connecting the movable sighting device and the indicator, and means constructed and arranged to prevent backlash in the mechanism, substantially as described.

7. In a device of the character described,

the combination of a bed-pIate a fixed and a movable sighting device mounted thereon, an indicator provided with a dial and pointer, a toothed sector arranged to operate said pointer, a rod jou rnaled on said bed-plate and provided with threads of different pitch at its respective ends, the threaded end of lesser vpitch operatively connected to said movable sighting device and the threaded-end of greater pitch arranged in mesh with said toothed sector, and means constructed to prevent backlash in the mechanism, substantially as described.

8. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator provided with a dial and pointer,

' 'a toothed sector arranged to operate said pointer, a rod j ournaled on said bed-plate and provided with threads of different pitch at its respective ends, the threaded end of lesser pitch operatively connected to said movable sighting device and the threaded end of greater pitch arranged to mesh with said toothed sector, and a spring-actuated wheel arranged and constructed to secure positive action and prevent backlash in the mechanism, substantially as described.

9. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an

indicator provided with a dial and pointer, a

plurality of ditferentlygraduated scales on said dial in position to be traversed by said pointer, an auxiliary pointer and auxiliary scale on the indicator, said auxiliary scale.

containing a number of divisions equal to the -number of said differently-graduated scales, and so arranged that the position of the auxiliary pointer will determine the particular scale on which the reading of the indicator is to be taken, a toothed sector arranged in operative connection with said first pointer and carrying said auxiliary pointer, a rod journaled on the bed-plate'and provided with threads of different pitch at its respective ends, the threaded end of lesser pitch operatively connected to said movable sighting device and the threaded end of greater pitch arranged in mesh with said toothed sector,

and means constructed to prevent backlash in the mechanism,substantially as described;

10. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an

indicator provided with a dial and pointer, a

plurality of differently-graduated scales on said dial in position to be traversed by said pointer, an auxiliary pointer and auxiliary scale on the indicator, said auxiliary scale containing a number of divisions equal to the number of said differently-graduated scales,

and so arranged that the position of the aux iliary pointer will determine the particular scale on which the reading of the indicator is to be taken, a toothed sector arranged in 0perative connection with said first pointer and carrying said auxiliary pointer, a rod jour-- naled on the bed-plate and provided with threads of different pitch at its respective ends, the threaded end of lesser pitch operatively connected to said movable sighting device and the threaded end of. greater pitch arranged in mesh with said toothed sector, and a spring-actuated wheel arranged and constructed to secure positive action and prevent backlash in the mechanism, substantially as described.

the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator provided, with a dial and pointer, a plurality of differently-graduated scales on said dial in position to be traversed by said pointer, an auxiliary pointer and auxiliary scale on the indicator, said auxiliary scale containing a number of divisions equal to the- IIO I 12 5 11. In a device of the character described,

number of said differently-graduated scales, and so arranged that the position of the auxiliary pointer will determine the particular scale on which the reading of the indicator is to be taken, a toothed sector arranged in operative connection with said first pointer and carrying said auxiliary pointer, a rod journaled on the bedplate and provided with threads of different pitch at its respective ends, the threaded end of lesser pitch operatively connected to said movable sighting device and the threaded end of greater pitch arranged in mesh with said toothed sector, a scale carried by said rod, a vernier adjacent said scale, and means constructed to prevent backlash in the mechanism, substantially as described.

12. In a device of the character described,

the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator provided with a dial and pointer, a plurality of differently-graduated scales on said dial in position to be traversed by said pointer, an auxiliary pointer and auxiliary scale on the indicator, said auxiliary scale containing a number of divisions equal to the number of said differently-graduated scales, and so arranged that the position of the auxiliary pointer will determine the particular scale on Which the reading of the indicator is to be taken, a toothed sector arranged in operative connection with said first pointer and carrying said auxiliary pointer, a rod journaled on the bed-plate and provided with threads of different pitch at its respective ends, the threaded end of lesser pitch operatively connected to said movable sighting device and the threaded end of greater pitch arranged in mesh with said toothed sector, a scale adjustably supported on said rod,means arranged to lock said scale in position on said rod, a vernier adjacent said scale, and means constructed to prevent backlash in the mechanism, substantially as described.

13. In a device of the character described, the combination of a bed-plate, a fixed and a movable sighting device mounted thereon, an indicator provided with a dial and pointer, a plurality of differentlygraduated scales on said dial in position to be traversed by said pointer, an auxiliary pointer and auxiliary scale on the indicator, said auxiliary scale containing a number of divisions equal to the maose number of said differently-graduated scales, and so arranged that the position of the auxiliary pointer will determine the particular arranged in mesh with said toothed sector, a

scale carried by said rod, a vernier adjacent said scale, and a spring-actuated Wheel arranged and constructed to secure positive action and prevent backlash in the mechanism, 1 substantially as described.

14. In a device of the character described,

the combination of a bed-plate, afixed and a movable sighting device mounted thereon, a

1 standard provided with a journal supporting said bed-plate, means for rocking the bedplate on its journal, comprising a worm car- 1 ried by said journal and an intermeshing Worm-wheel secured to the bed-plate, a base- 1 support for said standard, a frame on which said base'support is rotatably mounted, a

3 toothed sector secured to the base-support, 3 and an intermeshing Worm journaled on said 1 frame, substantially as described.

15. In a device of the character described, the combinationof a bed-plate, a fixed and a movable sighting device mounted thereon, a standard provided with a journal supporting ,said bed-plate, means for rocking the bedplate on its journal, comprising a Worm carried by said journal and an intermeshing worm-Wheelsecured to the bed-plate, a graduated sector carried by the bed-plate, a pointer secured to the journal and arranged to traverse said graduated sector, a base-support for said standard, a frame on which said basesupport is rotatably mounted, a toothed sector secured to the base-support, and an intermeshing Worm journaled on said frame, substantially as described.

In testimony whereof I affix my signature in the presence of two subscribing witnesses.

SARAH M. KERN. Witnesses:

ELLIS G. HUGHES, FRANK Mo'rrER.

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