US2309581A - Anemometer - Google Patents

Description

Jan. 26; 1943.

I w. c. ERWIN ANEMOMETER 4 Filed April 193, 1939 2 She'ets -Sheet 1 w; c. ERWIN ANEMOMETER Jan. 26, 1943.

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Patented Jan. 26, 1943 UNHTED STATES PA E'EN'E @FFICE ANEMOMETER William C. Erwin, Winthrop, Mass.

Application April 19, 1939, Serial No. 268,687

The present invention relates to improvements in anemometers and, as illustrated herein, relates more particularly to portable anemometers which are simple, compact, inexpensive and which may be easily carried from place to place in the pocket of the user.

The use of portable anemometers has been limited because these instruments are not only expensive but also because they are quite delicate and the movable-parts thereof, consequent- 1y, are not sufficiently rugged to withstand the shocks to which they are subjected. In some types of portable anemometers, it is not possible to read the wind or aircurrent velocity directly from the instrument. It is necessary to'utilize the reading of'the instrument in connection with other readings or to make other calculations before the wind or air current velocity can be determined. Another objection to prior portable anemometers is that they could not be quickly and accurately oriented with respect to the wind or air current direction and as a consequence readings taken from such instruments were not accurate. Another objection to prior devices was that even after the wind or air current velocity was accurately determined, no means was provided for indicating to the user the exact direction of the wind or air current.

One object of the present invention is to provide an improved anemometer by the use of which the above mentioned diificulties will be overcome.

Another object of the invention is to provide an anemometer with means for indicating the wind of air current direction simultaneously with the wind or air current velocity.

A further object of the invention is to improve generally upon the construction and operation of anemometers.

With the above and other object and features in View, the present invention will now be described with reference to the accompanying drawings in which:

.Fig. 1 is a View in front elevation, on an enlarged scale, of an anemometer constructed according to the present invention;

Fig. 2 is a view in section of the present invention illustrating the parts in position to be carried in'the pocket of the user;

Fig. 3 is a sectional View on a very much enlarged scale taken along the line 3-3 of Fig. 1;

Fig. 41's a perspective view showing the movable parts of the velocity indicating mechanism;

Fig. 5 is a'view in rear elevation of the device;

Fig. '6 is a top plan view;

Fig. 7 is a sectional view taken along the line 7-! of Fig. 3; I i

Fig. 8 is an enlarged cross sectional view of the means for securing the hair spring to thepointer shaft; Y

Fig. 9 is a view in end elevation of the hub shown in Fig. 8; I

Fig. 9a is an end View of the blade mounting; Fig. 10 is a view in cross section illustrating the means for securing the wind'vane to the top of the instrument;

Figs. 11 and 12 are views in side elevation, partly in section, illustrating two other embodiments of the present invention; V

Fig. 13 is a plan view of the device of Fig. I2; Fig. 14 is a cross sectional detail illustrating a modified form of compass;

Figs. '15 and 16 are plan'and side elevations respectively of means for reducing the displacement of the displaceable vane to permit the reading of higher Wind velocities than those marked on the indicating'dial; I

Fig. 17 is a plan view of a sectional vane for obtaining high Wind velocity readings;

Fig, 18 is an end view of thevane of Fig. 17

with the sections folded together;

Fig. 19 is a section taken along line 19-19 of Fig. 17. I

The present invention is illustrated as embodied in an anemometer enclosed in a casing sufficiently small to be easily and conveniently carried in the pocket of the user. 'The casing includes a generally cylindrical hollow cap and handle member 26 closed at one end and having an open internally screw threaded other end and a mechanism-supporting end cap 22 arranged to be threaded into the open endof the member 20. The member 23 is hollow and of suificient size to receive the movement of the anemometer within the casing as it is being carried from place to place. The cap 22 is provided with external screw threads 59, El adjacent to each end and on opposite sides of an intervening outstanding flange 23 in order that the anemometer may be positioned on the casing 29in the position shown in Fig. 1 or within the casing as illustrated in Fig. 2. The casing 26 forms a convenient means for gripping the instrument when it is in use and it forms a tight and dust proof container for the instrument as it is being carried from place to place. As illustrated, both the casing 25 and the cap 22 are suitably formed from an artificial plastic material such as resin or other suitable material.

The end cap 22 is hollowand the inner wall 24 thereof is substantially cylindrical. The bottom wall 26 of the cap 22 is provided with an integrally formed upstanding central projection 28 which is provided with a pivot pin 33 for a compass card 32 and attached underlying needle 33. The pin 38 may be inserted in the upstanding projection 28 either during the molding of the end cap 22 or may be driven into a hole formed in the projection 28.

The open end of the hollow end cap 22 is 3 upstanding projection 31 and is also provided with a hole 38 for receiving a rivet 43 which secures the anemometer to the transparent member 34. Said member 34 is also formed with a radially outstanding flange 39 which is seated upon the top face of the cap body.

From the above, it is evident that the compass card 32 is clearly visible through the fiat portion 36 of the transparent member 34. The inner surface of the flat portion 36 also prevents the compass card 32 from falling off of the pivot 30 since the distance between the top of the pivot 38 and the inner surface of the fiat portion 36 is less than the length of the bearing member 42 to which the compass card 32 is secured.

The compass card serves not only as a means for indicating the wind or air current direction but also as a means for properly leveling the instrument during use. That is to say, if the instrument is not level or plumb the compass card 32 will not rotate freely. When the instrument is plumb or level the instrument may be rotated to properly orient the instrument with respect to the wind without also rotating the compass card 32.

Referring now to Fig. 4, it will be noted that the anemometer mechanism comprises a back supporting plate 44 having a relatively long vertical portion 46 and a reflexed horizontal portion or foot 48 provided with a hole 58 for receiving the rivet 48 which secures the back plate 46 to the top surface 36 of the transparent member 34. Two posts or pillars 52 are secured to the upper end portion of the upstanding portion 46 of the plate 44 by rivets 54 or by any other suitable 1' means. A front plate 56 is secured at its upper end portion to the posts 52 by screws 58 in parallel relation with the back plate. The back plate 44 is provided with a hole to receive a vane shaft 60 which has a reduced forward end 62 arranged to enter an opening formed in the lower part of the plate 56. The shaft 69, as illustrated most clearly in Fig. 9a is provided with a flat side face 63 on its rear end portion to receive the lower end of a substantially vertical extending vane or blade 64. The lower end portion of the blade 64 is reflexed into a D-shape to surround the cut off portion of the shaft 60 and fits snugly and nonrotatably thereabout so that the shaft 68 will rotate as a unit with the blade 64.

The shaft 60 carries a gear segment 66 which fits tightly about the shaft between the back plate 44 and the front plate 56. The gear segment 66 meshes with a pinion gear 68 rigidly secured to a shaft 10 journalled in holes formed in the back and front plates 44 and 56. The forward end of the shaft I6 extends forwardly substantially beyond the front plate 56 and is slightly beveled adjacent to its reduced end portion to permit a collet 14 to be slipped onto the shaft, the collet gripping the shaft against independent rotation thereon. The extreme outer end portion of the shaft is reduced to provide a shouldered portion which carries a pointer 12.

The collet 14 (see Figs. 8 and 9), which is arranged to grip the inner end of a spiral hair spring 16, is fixed to the shaft 18 between the front plate 56 and the pointer 12. As illustrated, the collet 14 is provided with an annular recess 18 in which the end of the spring 16 is received.

The walls of the annular recess 18 adjacent to the end portion of the spring 16 are upset or turned inwardly to clamp the end of the spring to the collet 14. The collet 14 is also provided with a radial kerf 83 so that the collet 14 may be sprung on to the shaft 10 tightly enough to remain fixed in position. If, for any reason, it is desired to rotate the collet 14 relatively to the shaft 18, it is necessary only to insert a tool such as a screw driver in the kerf 80 to spread the same to free the collet 14 from the shaft 10. Then, when the collet 74 is in the desired posi tion relatively to the shaft 10, the end of the screw driver is removed and the collet 14 is again firmly clamped on the shaft 10.

The other end of the spiral spring 16 is fixed in a projecting lug 82 secured to the front face of the front plate 56 by riveting. The projecting lug 82 is provided with a hole into which the end portion of the spring 16 is inserted. A tapered pin 86 is then driven tightly into the tapered hole 92 to secure the end of the spiral hair spring 16 in position. The parts described just above are preferably formed of brass or other non-magnetic material that does not deleteriously influence the accuracy of the compass.

The enclosing casing for the movement is formed of a pair of spun brass shells each having a closed bottom and a laterally extending cylindrical portion. The back shell 88 has a radial end wall 89 and a cylindrical wall 80 provided with a slot extended rearwardly from one edge in which the back plate 44 is located. The shell is fixed to said plate by a screw 60a passed through said end wall and screw threaded into the upper part of said back plate below the parts 52 and above the shaft 7!].

The front shell 92 has a radial end wall 93 and a cylindrical wall 94 that is considerably deeper than and fits snugly within the cylindrical wall of the back shell and is provided with a slot 95 of substantially the same width as the width of the front plate 56. The depth of the slot from the open or rear end of the shell is substantially equal to the distance from the front face of the front plate 56 to the forward face of the rear plate 44. When the shells 88 and 92 are assembled with the movement, the end of the slot 95 formed in the shell prevents springing of the lower end of the front plate 56 away from the back plate by pressure applied accidentally, or otherwise, to the shaft 63.

The outer face of the end wall 93 of the front shell 92 is provided with a dial 98 which may be applied directly to the shell 92 by engraving or etching, or the dial may be in the form of a circular piece of suitable material affixed to the face 96. As illustrated, the dial is graduated to indicate miles per hour of wind or air current velocity. It is evident, however, that the face the shaft I which extends loosely through the wall :93.

.Atransparent moldedicover IIiZformed of any suitable transparent material .is :placed snugly over'the :shell :92 so that the end portion of the transparent cover .a'buts against the forward edge of the. rear shell .83 thusmaking a substantially smooth exterior surface for the device.

The blade 64 is protected from injury by a wire guard member llld which is fixed at one end to thetransparent cover member 3'4 and at its other 1 end to the top of the front cover or shell 92. The upper end portion of the wire guard I34 is bent into a substantially circular shape and fits in-a recess formed in the lower end portion of a cylindrical nut I98, Figs. 3 and 10. A screw I I9 extending through the front shell QZ cIamps the upper end of the wire guard against the shell 92. The other end of the wire guard I84 is fixed in a hole formed in the upstanding pro- .iection 3'! formed in the flat top plate 36 of the transparent cover member 34. This wire guard I64 gives protection to the blade 64 during handling and also prevents any undesired pressure from being applied to the rear end of theshaft 6B.

The upper'end of the cylindrical nut I08 forms a flat bearing surface for the horizontally extending portion of a vane H2. The vane H2 is formed, preferably, from a single piece of metal and has a flat substantially horizontal portion I! it and an upstanding substantially ver tical portion H5. The vane H2 is pivoted freely on a screw IM which is sufiiciently long to engage the end of the screw i538 without binding against the upper surface of the horizontal 'portion of the vane II2 which is thus free to rotate relatively to the instrument. The vane IE2 is so arranged that when the vane is over the higher velocity readings of the dial, the instrument is properly oriented relatively to the wind.

The modifications shown in Figs. 11 and 12 difier from the modification illustrated in the other figures, only in the construction of the end cap 22. As illustrated, in Fig. 11, the end cap 22 is provided with a separate flat transparent cover plate I2 which is held in position by a spring ring I26. The other parts of the device, the compass card and the anemometer are or can be substantially identical to the one previously described. In Fig. 12, the end cap 22 is formed of transparent material and the compass card 32 is mounted on an opaque member I28 which is held in position in the end cap by means of a spring wire ring I313.

The modification shown in Fig. 14 differs from the construction shown most clearly in Figs. 2 and 3 by providing a dish-like compass card having an upstanding cylindrical portion I34 on which the points of the compass may be marked. The bottom portion of the compass card I32 may be provided with similar marl:- ings if desired. This construction is particularly advantageous when the instrument is being used as a pelorus since when the instrument is being used as a pelorus the bearing may be read from the markings on the inside of the upwardly extending portion or wall, of the compass card.

The illustrated dial is graduated to provide readings of wind or air current velocity up to 30 miles per hour which is sufiicient for many purposes. Under some conditions, however, it

may be desirable to measure wind or air current velocity in excess of 30 miles per hour. This may be'accomplishedby changing the characteristics of the spring It by making it sti'fier and thus offering jgreater resistance to the movement of the blade 64. It is apparent however, that byincreasing the strength or tension of the spring It the instrument would be harder to read since the markings on the dial .face would becloser together. It is desirable, therefore, to ,prov-ide'means .for reducing the effective force of the wind or air current without changing the characteristics of the spring I6. To this end, as shown in Fig. 15, the instrument is provided with :a screen I35 which, when needed, can be swung into position in front of the blade 3. The screen I 35 is provided with a plurality of openings I36 which are so arranged that the effective force of the wind or air current on the blade 64 is reduced, for example, by onehalf. Thus, with a 40 miles :per'hour wind, for instance, the reading on the dial would be .20 miles per hour. The user of the instrument would multiply this reading by 2 and thus obtain the true velocity of the wind. It is apparent, however, that the screen or blade I35 could be provided with a smaller or larger number of openings I36 as desired to decrease or increase the effective force of the wind on the blade '64.

Thesoreen I35 as illustrated, is provided with an integrally formed substantially horizontal portion I38 which is provided with a hole 'arranged to receive the projection 37 l-fo-rmed on the flat portion 36 of the transparent member 34 which acts as a pivot for the screen I35. The projection 3! is threaded to receive an acorn nut I40 which maintains the screen I35 :in position. The acorn .nut I40 is provided with a holein its upper portion through which the lower end of the guide wire I04 is extended into the projection 31. The flat transparent portion 36 is provided with a stop member I42 against which the horizontal portion I38 is'swung when the screen is to be used. The portion '36 is also provided with another projecting stop member M4 against which the horizontal portion I38 is swung When it is desired to swing the screen I35 in operative position. The screen I35 may, however, be swung into some predetermined intermediate position as shown in dotted lines in Fig. 15 to increase the eifect of the wind on the blade 64. The factor by which the reading on the dial is to be multiplied may-be determined by comparing the reading with the reading of .a standard anemom'eter. The screen I35 would then act as a deflector and the increased volume of air striking the blade 64, would increase the sensitivity of the instrument particularly at low wind speeds.

The modification shown in Fig. 17 also relates to means for reducing the efiective force of the wind on the operating parts of the instrument. A blade I46 formed of two parts I48 and I59 pivoted at I52 is placed on the shaft 643 and is substituted for the blade 64 as shown in the other modifications. The portions I48 and I50 of the blade I48 are proportioned, as illustrated, so that when the portion I50 is swung downwardly about the pivot I52 into position behind the lower portion I48, more than one-half, or other desired portion, of the initial blade area is acted on by the wind. Thus with the portion I50 positioned behind and covered by the portion M8, the reading on the dial may be 20 miles per hour, but since the effective force of the blade area is only half that for which the scale was calibrated, this reading will be multiplied by two or other suitable factor to give the true velocity of the wind which is 40 miles per hour. In order to insure that the parts I48 and I50 will be maintained in proper position, the blade I 50 is provided with a pair of detents which fit into indentations I54 formed on the portion M8. These indentations are so arranged relatively to the pivot I52 that they will engage the detents in the portion I50 in either position of the portion I50.

When using the instrument, it is removed from its enclosing casing 20, inverted and screwed into the position shown in Fig. 1. The device is held in the hand as nearly plumb as possible with the vane H2 in line with and over the high speed side of the dial, the vane, of course, being pointed into the wind by the action of the wind on it, like a weather vane. The device is then rotated about in the hand, if necessary, to position the blade 64 and its shaft at right angles to the vane so that the blade is perpendicular to the wind. This position can be determined easily and accurately by observing when the vane is parallel with the end walls of the mechanism casing. The wind thus acts with maximum effect to deflect the blade and rotate the pointer over the dial until the wind pressure on the blade is resisted by the equal tension, as modified by the gearing, of the hair spring. It is apparent that by properly orienting the instrument an accurate reading of wind or air current velocity may be made.

As shown more clearly in Figs. 2 and 12, the under surface of the transparent face 36 of the member 34 is provided with a groove H6 extended across said face forming a line extending parallel to the dial face 98 at one side of the vertical center of the compass pin 30 and in front of the wind velocity dial and perpendicular to the axis of the blade shaft 60. Thus when the eye of the observer is in a position as indicated at H8 in Fig. 12, his line of vision will pass through the line H6 and intersect the compass card 32 along a line passing through the center of the card and thus he can, without shifting the position of his eye, read the magnetic bearing on the compass card 32. This forms a convenient way of reading both the wind velocity and wind direction without shifting the view and without attempting to See compass points bscured by the velocity indicator.

The device above referred to may also be used as a pelorus for determining the users position with relation to other fixed bodies. In using the device for this purpose, the user sights along the back edge of the shell 88, Fig. 3, and then by taking a reading along a diametric line formed by a notch or groove I20 formed in the under surface of the transparent plate 36 parallel with the groove I I6 may determine his magnetic bearing with relation to the sighted object. He may make one or more readings by sighting on other objects, and thus determine his position relatively to these objects. It would be necessary, of course, in order accurately to determine the users position, to plot out his position on a Scale, map or chart on which the sighted objects are indicated. The groove I20 being over the compass pin 39 forms a witness line for the compass by which the hearing may be determined.

Having thus described my invention. what I claim as new and desire to secure by Letters Patent of the United States is:

1. In an anemometer, a frame, anemometer mechanism carried by said frame, an enclosure for said mechanism and at least a part of said frame comprising front and rear closure members having end walls and cylindrical side walls, the cylindrical side wall of one member being telescoped within the cylindrical side wall of the other member, one of said end walls carrying wind velocity marks, said anemometer mechanism including a pointer operated by a displaceable blade and movable with respect to said marks, a transparent cover telescoped over said front closure member for said pointer and marks, a mechanism operating shaft carried by said frame and extending outwardly of said enclosure, and a wind impact blade fixed to said shaft.

2. In an anemometer, a frame comprising a pair of confronting spaced vertical plates, anemometer mechanism carried by said plates, an enclosing casing for said mechanism and at least a part of said frame, including front and rear'closure members each having an end wall and a cylindrical side wall, the cylindrical side wall of said rear closure member having a slot therein in which one of said plates is located, the front closure member having its cylindrical wall telescoped within the cylindrical wall of said rear closure member and having a slot in its cylindrical wall in which the other of said plates is located, the front face of the end wall of said front closure member having wind velocity marks thereon, said anemometer mechanism including a needle located in front of said front face and movable relatively to said marks, an enclosure for said needle and marks including a member having a transparent front wall and a cylindrical side wall fitting over the cylindrical side wall of said front closure member, one of said plates being extended laterally of said casing and providing a support for the device, a shaft extended from said casing having an operative connection with the aforesaid mechanism, and a wind impact blade externally of said casing fixed to said shaft.

3. In an anemometer, a compass box having a transparenut cover and a compass card under the cover, anemometer mechanism located above the cover and carried by said box and having a wind displaceable vane, and means for visually indicating the amount of displacement of said vane, said cover having a witness line visible from the point of view of said indicating means and at one side of the card pivot and in predetermined relation to said anemometer vane for determining the orientation of said anemometer.

4. In an anemometer, a housing comprising a rear housing member having a rear end wall and a cylindrical side Wall, a front housing member comprising a front end wall and a cylindrical side wall that is located within and snugly fits the side wall of the rear housing member, anemometer mechanism enclosed between said end walls and including a shaft extended through the rear end Wall and provided at its outer end with a blade, an indicating shaft connected operatively with said first shaft and extended through said front end wall and having a pointer thereon rotatable over the front face of said front end wall, said front face having a dial thereon, and a cover member having a front end wall and a cylindrical side wall both integral and composed of transparent material, said transparent side wall surrounding and engaging the cylindrical side wall of said front housing member and confronting the end of the cylindrical side wall of said rear housing member.

5. In an anemometer as in claim 4;, the transparent side Wall of said cover member having a notch therein, and an upstanding post located in said notch and fixed to the side Wall of said front housing member.

6. In an anemometer, a pair of spaced parallel upright plates, means securing said plates rigidly together in the aforesaid relation, the lower end of one of said plates being longer than the other and terminated in an attaching foot extended at an angle with the body of the plate, a blade shaft journalled in said plates, a blade fixed to said shaft, an indicating shaft journalled in said plates, gearing connecting said two shafts, a spring connected between one of said plates and said indicating shaft to oppose displacement thereof, a housing for said plates, and said housing comprising a rear housing member having a rear wall and a forwardly extending cylindrical side wall, a front housing member having a front end wall and a rearwardly extending cylindrical side wall fitted within the side wall of said rear housing member, said indicating shaft being pased loosely through said front end wall, a pointer fixed to said shaft and movable over said front wall, said front Wall having a dial thereon cooperating with said pointer, and a transparent cover member having an end wall and an integral cylindrical side wall fitted over the side wall of said front housing member and confronting the end of the cylindrical side wall of said rear housing member, said one plate and its attaching foot being extended through a slot of said rear housing member.

7. Apocket-type anemometer comprising a cylindrical supporting base having external screw threads on both ends, a hollow tubular handle having internal screw threads on one end arranged to be screw threaded on the external screw threads at either end of said base and when on one end to form a handle for holding the anemometer in operative position and when on the other end to enclose and protect the operative parts of the anemometer, said base having a recess in one end thereof, a needle pivot in said recess, a compass needle on said pivot, a transparent cover for said recess, an anemometer casing located closely above said cover having a transparent front wall and a wind-velocity indicating dial and pointer closely back of said front wall and near the axial line of said needle pivot to expose said needle and said dial to concurrent view, a wind blade carried by and disposed externally of said casing, mechanism operatively connecting said blade and pointer, said blade and casing being located entirely Within the outline of said screw threads to fit within said hollow handle.

7. A pocket-type anemometer as in claim 7, said anemometer casing having means fixing it directly to said transparent cover.

9. A pocket-type anemometer as in claim 7, said transparent cover comprising an inverted cup-shaped member having a transparent end wall which overlies said needle and a cylindrical side wall which fits within said recess, means directly connecting said anemometer casing with said end wall which constitutes the support for said casing, and a stiff guard wire fixed to said cylindrical Wall and to said casing and closely bounding the edge of said wind blade.

WILLIAM C. ERWIN.

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