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Publication numberUS2649848 A
Publication typeGrant
Publication dateAug 25, 1953
Filing dateFeb 11, 1949
Priority dateFeb 11, 1949
Publication numberUS 2649848 A, US 2649848A, US-A-2649848, US2649848 A, US2649848A
InventorsArmstrong Daniel A
Original AssigneeScott Atwater Mfg Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Speed indicating device for outboard motors
US 2649848 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Aug. 25, 1953 D A. ARMSTRONG FOR OUTBOARD MOTORS Filed Feb. 11, 1949 SPEED INDICATING DEVICE 2 Sheets-Sheet 1 Inventor: DIM/4 fl. flaws rmwv r Attoi g Aug- 25, 3 D. A. ARMSTRONG 2,649,848

SPEED INDICATING DEVICE FOR OUTBOARD MOTORS Filed Feb. 11, 1949 2 SheetsSheet 2 Inve 111: o r fill/WEI. A. flRMsTRO/v4 warned against overspeeding of the motor.

Patented Aug. 25, 1953 SPEED INDICATING DEVICE MOTORS FOR OUTBOARD Daniel A. Amsmng, Minneapolis, Minn., assignor to Scott-'Atwater Manufacturing Company, Minneapolis, Minn., a corporation of Minnesota Application February 11, 1949, Serial No. 75,933


This invention relates to an outboard motor and particularly to a structure of outboard motor adapted to have a speed indicator carried thereby. It is desirable to have an indicator on an outboard motor which will be disposed so that it can be easily and conveniently observed by the operator so that he can tell at what speed the motor is operating. The operator will thus be It is also desirable to know the operating speed of the motor so that the propeller can be selected for most efiicient performance.

It is an object of this invention to provide a very simple and yet very efficient speed indicating device which can be conveniently and inexpensively secured to the outboard motor.

It is a further object of the invention to provide an outboard motor structure comprising a frame, a motor proper secured to said frame, a second member secured in rigid relation relatively to said frame and motor, said second member having a surface to which is attached a plurality of spaced elongated narrow thin resilient strips, said strips having free ends disposed differentdistances from their points of support,

said member being constructed and arranged so that the end portions of said strips are visible to the operator, and said second member having indications thereon adjacent each of said strips indicating speeds of said motor respectively.

It is more specifically an object of the invention to provide an outboard motor structure comprising a member secured to said motor, which member may constitute the gas tank cover and which preferably has a downwardly sloping exterior surface at one end, a thin plate-like member of resilient material having projecting from one end thereof elongated resilient strips, means for securing said plate-like member to said first mentioned member so that said strips project different distances from their points of support and thus have difierent effective lengths respectively, said first mentioned member having an opening therethrough through which the end portions of said strips are visible, and indications on said exterior surface aligned with each of said strips indicating rotative speeds of said motor.

These and other objects and advantages of the invention will be fully set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:

Fig. l is a. plan view of a portion of the gas tank cover of an outboard motor;

Fig. 2 is a view in end elevation of Fig. 1;

Fig. 3 is a bottom plan view of a portion of said gas tank cover;

Fi 4 is a vertical section taken on line 44 of Fig. 3, as indicated by the arrows, but not being inverted;

Fig. 5 is a plan view of. a reed-forming member used;

Fig. 6 is a view in side elevation of the device shown in Fig. 5; v

Fig. '7 is a top plan view of a securing member; and

Fig. 8 is an end view of the member shown in Fig. 7.

Referring to the drawings, a member 10 is shown, and While this might constitute different parts of the motor, in the embodiment of the invention illustrated it shows the gas tank cover of the outboard motor. Said member ID has a rim Illa which is arranged to engage the main portion of the gas tank (not shown) and be secured thereto. Member ID has a lug lob at one side provided with an opening extending therethrough through which the pull cord for starting the motor extends. Member ID has an opening lOd adapted to receive a bolt for attaching said cover. At its inner side member. I0 is provided with a lug l0e which has a flat surface If. A member II is provided, shown in Figs. 5 and 6, which is made of a thin plate and which will be made of some strong resilient material which may be metal, fiber, plastic or other suitable material. Member I I has a plurality of spaced slots Ila formed therein which divide one end of said member into a plurality or multiplicity of narrow elongated strips llb. These strips are shownas of substantially equal widths and the slots Ila. are substantially of the same width so that said strips as shown are equally spaced. The end portions of strips [ID are bent at an obtuse angle, as shown at ilc. Member II is provided with a pair of spaced holes lld. A pair of attaching members l2 are provided, as shown in Figs. 7 and 8. Each of these members comprises a flat bar preferably made of metal having one straight side and straight or flat end portions, the other side of said member being provided with a series of steps I241. so that the width of member I2 is successively smaller toward one end. Members I2 are provided with a pair of spaced holes 1212. As shown in Fig. 4, the member II is secured between members l2 by bolts 13 extending through the holes I212 in members l2 and through the holes lid in member ll. Spring washers M are 3 shown beneath the heads of bolts 13. Bolts l3 are firmly secured in the lugs We and one end of member H is tightly clamped between members 12 so that said member is very tightly secured in position. Owing to the step formation of members [2, the strips lib will extend different distances from the points at which they are secured so that the free length or effective length of said strips lib will be different. Member 10 is provided with an openingjflg through which the end portions of strips Hb are visible. opening [0g is shown as covered by a transparent plate [5 which may be secured to "member ID by screws ll. Member 10 has placed thereon, as shown in Fig. l, indications [6 which are respectively aligned with the strips llb. Indications I6 indicate motor speeds or .revolutionsper minute of the motor.

In operation, when the motor is running, the resilient strips l lb which form in effect reeds, will be supported as described, with their projecting ends free. Said strips or reeds will vibrate at certain speeds of the motor. The reeds vibrate at twice the frequency of the revolutions of the motor. When the motor reaches a certain speed, say 3,000 revolutions per minute, the end one of said strips lib, as shown in the left of Fig. 1, will vibrate in resonance with the revolutions or vibrations of the motor. The vibration or vibrating movement of said strip can readily be seen by the operator. This will indicate that the motor speed is then 3,000 revolutions per minute. As the motor speed increases the different strips or reeds I lb will vibrate in unison or in resonance with the motor speed. The operator thu needs only to observe whichstrip or reed is vibrating and the motor speed will beindicated by the respective indications [6. The strips or reeds lib can of course be constructed and calibrated to indicate the desired R. P. M. of the motor.

From the above description it will be seen that I have provided a very simple and efficient structure of speed indicating means which can very easily and inexpensively be provided in an outboard motor. The speed indicator has a high degree of utility in its use with the motor and will enable the operatorto avoid excessive speed or to avoid running the motor at too high a speed for long periods. It has been previouslynecessary in order to check the speed of the outboard motor to use a portable tachometer which would engage the driving shaft or propeller'shaft. The operation of such a tachometer was difficult and particularly so with the modern outboard'motors which have a hood surrounding the engine. The indicator will also have utility in indicating-the speed of the motor so that the proper propeller This selection can be had. With the speed indicator the motor can be easily operated with much better efficiency. By constructing the reeds so that they will vibrate at twice the frequency of the motor revolution a much shorter reed can be used. The short reeds are more easily and inexpensively made and take up less room so that a compact structure is possible. The device has been amply demonstrated in actual practice and found to be very successful and efiicient.

It will of course be understood that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which generally stated, consists in a device capable of carrying out the objects above set forth, in the partsand combinations of parts disclosed and defined in the appended claim.

What is claimed is:

A combined outboard motor and tachometer structure having in combination, a motor body, a gas tank mounted on said body, and a gas tank cover secured to said gas tank so as to vibrate in unison with said motor body, said cover having a portion projecting at one side thereof, said portion having downwardly sloping sides and end and having a chamber therein, a boss in said chamber having a substantially flat surface thereon, a member attached to said surface, a plurality of spaced reeds secured to said member having downturned ends and projecting toward said end, said reeds being of different lengths, said portion having an opening therethrougn through which the end portions of said reeds are visible, and numbers on the outer side of said first mentioned portion aligned with said reeds respectively for indicating speeds of said motor whereby said cover functions as a cover for said gas tank and also functions as a casing for said tachometer structure.


References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 759,513 Frahm May 10, 1904 1,028,488 Pontius June 4, 1912 1,315,646 Sticht et a1 Sept. 9, 1919 1,416,550 Frank May 16, 1922 1,613,727 Schmidt Jan. 11, 1927 1,738,772 Harry Dec. 10, 1929 OTHER REFERENCES Power, January 1944, an advertisement by the James G. Biddle Co. appearing at page 144 (62c).

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US759513 *Aug 28, 1902May 10, 1904Hermann FrahmApparatus for measuring the revolutions of rotating shafts.
US1028488 *Jun 15, 1907Jun 4, 1912A R Mosler & CoMagnetic speed-indicator.
US1315646 *Mar 7, 1919Sep 9, 1919American Precision WorksAnd karl oeorg frank
US1416550 *Sep 4, 1919May 16, 1922Georg Frank KarlVibrating reed instrument
US1613727 *Dec 17, 1924Jan 11, 1927Westinghouse Electric & Mfg CoFluid tachometer
US1738772 *Sep 17, 1928Dec 10, 1929Ac Spark Plug CoOutboard-motor tachometer organization
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2798472 *Feb 13, 1956Jul 9, 1957Kiekhaefer CorpEngine tachometer
US4465047 *Mar 22, 1982Aug 14, 1984Nippon Soken, Inc.Knock detecting apparatus for combustion engines
US4587935 *Feb 8, 1985May 13, 1986Sanshin Kogyo Kabushiki KaishaOutboard motor with engine tachometer
US4613310 *Oct 22, 1984Sep 23, 1986Sanshin Kogyo Kabushiki KaishaOutboard motor
U.S. Classification123/198.00E, 123/2, 73/651, 73/506, 440/2
International ClassificationG01P3/14, G01P3/02
Cooperative ClassificationG01P3/14
European ClassificationG01P3/14