US2680969A - Governor with over-center spring snap-action output - Google Patents

Description

June 15, 1954 w. J. SPENGLER 2,680,969

GOVERNOR WITH OVER-CENTER SPRING SNAP-ACTION OUTPUT Filed May 26, 1950 FIG. I.

, 1 3 MIIIIH INVENTOR ATTORN EY Patented June 195 4 UNITED STATES TENT OFFICE GOVERNOR WITH OVER-CENTER SPRING SNAP-ACTION OUTPUT Walter J. Spengler, Sidney, N. Y., assignor to Bendix Aviation Cor poration, New York, N. Y.,

2 Claims.

This invention relates to speed responsive control apparatus and more particularly to centrifugally controlled toggle or snap-action devices such as electrical switches or the like.

One of the objects of the present invention is to provide apparatus embodying novel means for controlling the operation of a toggle or snapaction device in accordance with the angular speed of a rotating part.

Another object of the invention is to provide novel means for actuating and centrifugally controlling an electrical circuit making and breaking device.

A further object is to provide novel means and apparatus of the above character which comprises only a small number of light and simply constructed parts adapted to be assembled in a relatively small space.

Still another object is to provide a novel speed responsive device which may be combined in a novel manner with a rotating shaft whereby the latter extends through the device for the transmission of power.

A still further object is to provide novel circuit breaker mechanism which is so constructed as to automatically open or close an electrical circuit at a predetermined speed on acceleration and to close or open said circuit at a different or lesser speed on deceleration.

Another object is to provide a centrifugally operated electrical circuit make and break device which takes full advantage of the small amount of centrifugal force required to thereby reduce the size and weight of the device without sacrificing essential strength, efficiency or dependability.

Another object is to provide novel electrical circuit breaker mechanism which lends itself readily to actuation by centrifugally responsive means and is so constructed that no brushes or the like are required for making necessary electrical connections.

Another object of the invention is to provide novel apparatus which may be combined with the speedometer of a motor vehicle for'controlling a selected means on the vehicle in accordance with the speed of the latter.

The above and further objects and novel features of the invention will more fully appear from the following detail description when the same is read in connection with the accompanying drawing. It is to be expressly understood, however, that the drawing is for the purpose of illustration only and is not intended as a definition of the limits of the invention.

In the drawing, wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a side elevation view showing one embodiment of the invention adapted for use in controlling the transmission of a vehicle, for example, in accordance with the speed of the vehicle;

Fig. 2 is a sectional side elevation view of one type of centrifugally controlled circuit breaker unit, adapted for use in the structure shown in Fig. 1, the section being taken substantially on line 2-2 of Fig. 1;

Fig. 3 is a transverse sectional view with parts broken away, the section being taken substan tially on line 33 of Fig. 2;

Fig. 4 is an isometric View, partly in section and with parts broken away, the view being taken from the left in Fig. 2 with the casing cover removed; and

Fig. 5 is a detail exploded isometric view of some of the partsof said unit,

The single embodiment of the invention illustrated in the drawing, by way of example, is in the form of a control unit adapted for use in conjunction with the speedometer of a motor vehicle or the like to control the operation of an electrical switch in accordance with the speed of the vehicle. The switch may, for example, control a circuit .to ari'electrically operated means for controlling the transmission%for other functional apparatus on the vehicleinot shown) in a desired manner and in accordance with variations in vehicle speed. For example, the control means may be operative to effect shifting of the transmission fromone gear ratio to. another and back again at different predetermined vehicle speeds. As a more specific example, the present device may effect a shift into so-called overdrive in modern automobiles at one vehiclespeed and a shift back to regular drive at alower predetermined vehicle speed. The unitmay, of course, be operatively associated with any other rotating part to efiect control in accordance with the speed of rotation of the part.

As shown in Fig. 1 the novel control unit it is operatively associated with a speedometer: l I- which may be of the type extensivelvused on automobiles, trucks and like vehicles, the same being operatively driven from an engine or vehicle driven part (not shown) which rotates at a speed proportional to the speed of the vehicle. The transmission of power from the driving part may be through a flexible shaft I i housed in a flexible armor l2 and through the novel control comprises the rotating shaft 16-48 which is journalled in a flanged stationary supporting member 59. Axial movement of the shaft relative to the support may be prevented by providing a collar 26 on the shaft and flaring the hollow end thereof as shown at 2 l The operating parts may be enclosed by a cup-shaped cover or casing member 22 which may be removably secured to flanged support [9 and to the speedometer casing by a nut 23 surrounding shaft H.

The snap-action device or switch embodied in the present invention consists wholly of non-rotatable parts and in the specific form shown, by way of example, comprises a stationary contact 2 on a bracket 25 of electrically conductive material. The latter is mounted on and suitably insulated from support member 59 by means including a rivet 25 and a terminal screw 21 which extends through the support for connection with a lead 28 externally of easing i9, 22. The lead may be part of a circuit including an electrical device such as a solenoid, for example, and a source of electrical energy, such as a battery or other source. A movable contact carrying member 28 carries a contact 3% and is mounted for substantially frictionless pivotal movement relative to the supporting member 19.

For mounting member 29 and for limiting movement thereof in one direction, a bracket 30 is secured to support 59 in some suitable manner, such as by rivets. The supporting member may have a recess 32 therein for this purpose. lhe end of the upstanding portion of bracket 3t nearest shaft it and the corresponding end of contact carrying member 29 are centrally slotted or bifurcated to straddle a spring 33, the function and operation of which will be hereinafter fully described. Any suitable known meth- 0d of pivotally mounting member 29 on bracket 39 may be used, and as shown the ends 34 of the arms or bifurcations of the bracket are of reduced width and bent to form bites or notches in which the bifurcations or arms of member 29 are loosely received. Lateral movement of said member in the direction of the axis of shaft 15 is prevented by extensions on member 28 which straddle the bent ends 3d in the manner best illustrated in Fig. 4.

Movement of the contact carrying member 29 between its limiting positions against brackets 25 and 38 is effected by spring 33 and a pivoted actuating member 35. The latter is journalled for free pivotal movement about a boss on support i9 and is secured in position by a screw or rivet. The pivotal axes of members 29 and 35 are located on a line which extends between brackets 25 and 36 and hence, between the extreme or stop positions of contact member 29. Member 35 is formed with two arms or bifurcations 35 and 3'! that straddle shaft it, the arm 36 extending into the vicinity of the pivotal axis of member 29 and being connected t the inner end of spring 33. Since the arm 3'1 is cut ed by the section in Fig. 2, the same is illus- 4 trated in phantom or dotted lines in said figure in the interest of clarity.

The construction is such that when arm 3-6 is moved to the full line position illustrated in Figs. 3 and 4, spring 33 will pivot contact member 29 in a clockwise direction, as viewed in Fig. 3, with a quick snap-action and then resiliently press contact 3I- into engagement with stationary contact 2Q. An electrical circuit will thus be completed through said contacts, lead 28, and ground or such other return lead as may be connected to contact 3!. When arm 35 is moved to the dotted line position shown in Fig. 3, thereby moving the end of spring 33 to the right and past pivot 34, the line of action of the spring becomes such that toggle member 29 will be snapped to the right in a counter-clockwise direction into engagement (dotted line position) with bracket 39, thereby breaking the circuit at contact 2%.

The necessary pivoted movement of forked member 35 is effected in a novel manner in accordance with and in response to the speed of shaft It by means rotatable with said shaft and cooperable in a novel way with said member. In the form shown arm 37 has a bend 33 therein so that the end portion thereof adjacent shaft 16 is in a different transverse plane than the corresponding portion of arm 38, i. e., a different plane perpendicular to the axis of rotation of the shaft. Surrounding an enlarged portion of shaft I6 adjacent support member 59 is a sleeve 39 which has a cam lobe or lug as projecting from the outer surface thereof'for cooperation with lever arms 36 and 3? in a manner to hereinafter more fully appear.

Suitable means are provided for causing sleeve 39 to rotate with shaft i6 and to move axially thereon in response to the speed of shaft it. As illustrated said means are of the centrifugally actuated type and comprise a leaf spring ii mounted on shaft 26 for rotation therewith. The driving connection may be effected by providing a rectangular hole in the spring to fit the squared portion ll of the shaft. Spring M may be fixedly or adjustably secured against axial movement on shaft E6 in any suitable known manner, resilient lips or tongues 42 at the ends of the opening in the spring being employed for this purpose in the illustrated embodiment. The tongues resiliently engage the shaft and prevent unintentional or accidental movement of the spring axially away from the shoulder on shaft l5 formed by the enlarged cylindrical portion thereof within sleeve 39. In another suitable embodiment a washer having portions thereof staked or spread into grooves in the shaft is used to secure the spring against said shoulder.

The end portions of spring l! are inclined away from sleeve 39, the same making an acute angle with the axis of shaft rotation. A loop or bight is formed at each end of spring li for resiliently gripping and supporting a flanged or spool-like weight member 53. Thus, when the shaft rotates with spring GI and weights 53, centrifugal force which is proportional to speed tends to throw the weights away from the axis of rotation and hence, to bend the ends of the spring M to the right, as viewed in Fig. 2, toward a position perpendicular to said axis. Adjustments to get desired operation may be readily made by bending spring 4! to change the ini-- tial angle of the arms thereof. Similar results may be effected by increasing or decreasing the mass of weights 43. V

This motion, which is thus centrifugally imparted to spring di, and the rotary movement thereof are transmitted to cam sleeve 39 through a rigid member id having oppositely extending inclined arms. The latter are preferably spaced a short distance from the corresponding arms of spring ii and extend between the flanges of weight members d3, whereby the rotary movement of the shaft is imparted to motion transmitting member itthrough spring di and weights 3. The central flat portion of member i has an oblong opening 45 (Figs. 4 and 5) and the end of sleeve 39 has portions thereof cut away (Fig. 5) to make it fit into said oblong opening and thereby effect a rotary driving connection between member Ml and sleeve 39.

The rigid arms of member 46 operatively engage the inclined ends of spring 4| so that flexing of the latter in response to centrifugal force will move member #4 and hence sleeve 39 axially along shaft it. Such engagement or its equivalent may be effected in various ways, such as by pressing a bead it in each of said arms to make substantially point contact with the spring and hence minimize friction. The outer or free ends of rigid arms 34, 4 3 may be curved as best seen in Fig. 2 to limit the movement of weights 43, d3 radially from the shaft.

It will thus be seen that as the arms of spring GI are flexed in response to centrifugal force, member 4 and sleeve 39 will be moved bodily to the right (Fig. 2). This axial movement of sleeve 39 is yieldably resisted by suitable resilient means such as a coil spring 4? (Fig. 2) surrounding shaft 56 between collar and an internal shoulder in sleeve 39. Beads 56 may be replaced by adjustable set screws or the like in arms 44, whereby the speed at which spring ll will engage and start to move member M may be readily varied or adjusted. Adjustment could also be effected by providing means to change the initial compression of spring 47.

When the parts are at rest or rotating at slow speed, spring 51 urges sleeve 39 and member id to the illustrated position against spring ll which acts as a stop. In this position, cam lobe 4b is in the plane of arm 37 so that upon rotation of the shaft, members 35 and 29 will assume their dotted line position (Fig. 3), that is, open circuit position. As the speed of the shaft increases, sleeve 39 is moved axially toward support I 9 in response to centrifugal force, until cam lobe 36 moves into the plane of toggle arm 36 and moves the latter away from the axis of rotation to effect a snapaction of contact member 29 into circuit closing position (full line, Fig. 4) as heretofore described.

The angle between arms 36 and 37 and the loca-' tion of the snap-action device on support I 9 is such that when the member 35 is in full line position (Fig. 3) the arm 36 will be out of reach of the rotating cam lobe 40 and arm 31 will be sufficiently close to sleeve 39 to be engageable by the lobe when it moves into the same plane therewith. Likewise, when the cam lobe has moved fork lever 35 to dotted line position (Fig. 3) the parts will be held by spring 33 so that arm 37 will be out of reach of the cam lobe and arm 36 will be close to the sleeve for engagement by the lobe when it is moved into the same plane.

As will be understood by those skilled in the art, the characteristics of the resilient means 4| and ll which oppose the centrifugal force in this device may be such that the axial movement of sleeve 39 will be gradual as the rotary speed increases. On the other hand, said characteristics may be such that when the initial tension or force of the springs is overcome by centrifugal force, the sleeve will move rapidly to its other extreme position without further appreciable increase in speed. In either event, the parts may be designed and adjusted so that sleeve 39 will move lobe 49 into the plane of arm 36 at a predetermined or selected speed of shaft I 6 and back into the plane of arm 3! when the shaft has been slowed to a predetermined or selected lower speed. The switch 2%, M is accordingly closed at a predetermined speed of shaft I6 and remains closed at all speeds and until the speed is reduced to a predetermined lower speed. It is of course clearly apparent that the switch may be opened at the higher speed and caused to close at the predetermined lower speed, either by reversing the planes of levers and 31, or by changing the electrical connections.

The novel speed responsive means for imparting axial movement to sleeve 39 is claimed in application Serial No. 164,552 of Rolland M. Purdy and Harald Mainusch for Centrifugal Speed Responsive Apparatus Having Spring Supported Weights filed May 26, 1950.

Although only a limited number of embodiments or modifications of the invention are illustrated in the drawing and described in the foregoing specification, it is to be expressly understood that the invention is not limited thereto. For example, various other known types of centrifugally responsive devices may be employed for actuating sleeve 39 and rotary movement may be imparted to said sleeve directly from shaft It,

' such as by a key or land or in any other suitable manner. Other known means may also be provided for securing spring 4| against axial movement on shaft H. The snap-action or over-center device may, if desired, be utilized for a purpose other than electric switch means. Various other changes may also b made, particularly in the design and arrangement of parts illustrated, without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

What is claimed is:

'1. In apparatus of the class described, a rotatable member, cam means mounted on said member for rotation therewith and limited axial movement relative thereto, resilient means for yieldably resisting axial movement of said cam means in one direction, centrifugally responsive means on said member for imparting axial movement to said cam means against the resistance of said resilient means, a pivoted bifurcated lever astraddle of said member, the furcations being in axially spaced planes perpendicular to the axis of rotation for individual engagement by said cam means at different speeds of rotation of said member, a snap-action element pivotally mounted for limited angular movement, and a spring under tension connecting said element and the free end of one of said furcations whereby movement of the lever from one predetermined position to another by said cam means renders said spring effective to snap said element from one of its limiting positions to the other.

2. In apparatus of the class described, an overcenter spring snap-action device comprising a stationary support having a V-shaped notch therein, a rigid plate-like element pivotally mounted for limited angular movement about an edge thereof engaging said notch as a pivot, normally biased resilient means under tension for yieldably holding said element in one or the other of its limiting positions and a pivoted bifurcated lever connected to said resilient means for moving the latter to render it efiective to move said element from either of said positions to the other with a snap action, the pivotal axis of said lever being spaced from the pivotal axis of said element and on the side thereof remote from the free end of said element, a rotatable shaft, and means responsive to the speed of said shaft for actuating said lever including cam means having a lobe straddled by the furcations of said lever and centrifugally responsive means for axially moving said cam means, whereby said lobe is adapted to selectively engage the furcations of said lever and pivotally move the latter in difierent directions at different speeds of shaft rotation to efiect said movement of the resilient means.

References Cited in the file of this patent Number UNITED STATES PATENTS Name Date Goeller Mar. 25, 1924 Johnson May 10, 1938 Taylor Jan. 16, 1945 Pearce Aug. 31, 1948 Clark Mar. 1, 1949 Price Apr. 5, 1949 Randol Dec. 19, 1950 FOREIGN PATENTS Country Date France Jan. 18, 1950

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