US3228254A - Snap on control mechanism - Google Patents

Description

Jan. 11, 1966 BIESECKER 3,228,254

SNAP ON CONTROL MECHANISM Filed May 28, 1963 Fig'z Fig. 4-

TQM/46 INVENTOR. Dona/o L. B/e'sec/(er WMBTQM ATTORNEY United States Patent 3,228,254 SNAP 0N CONTROL MECHANISM Donald L. Biesecker, Dayton, Ohio, assignor to Illinois Tool Works Inc., Chicago, 11]., a corporation of Dela- Wille Filed May 28, 1963, Ser. No. 283,900 6 Claims. (31. 74-104 This invention relates in general to snap on assemblies and more particularly relates to a knob and stem means integral therewith which are adapted to be inserted through an aperture and snap on to an independently mounted lever arm member.

Gasoline powered implements and motors, such as outboard engines, generally have a choke control which is manually actuated. For aesthetic and for functional reasons the motor and the carburetor associated therewith is oftentimes covered by a bezel or housing. Since the controls for the motor, such as the choke control, need to be on the exterior for quick actuation thereof by the operator, the assembly of the housing over the motor poses some problems. For example, the control knob, if it is fixedly attached to the lever mechanism which operates the choke control, must be made in such a manner that it is possible to assemble the housing over the motor and to this end many times the knobs are detachable so that an extremely large sized aperture need not be provided so that the housing will fit over the knob. Detachable knobs are objectionable since they often jiggle loose from the vibration of the motor or otherwise become detached. A further problem sometimes encountered with the prior art devices relates to the connection between the end of the stem of the knob member and the pivotally mounted arm which controls the position of the member to be controlled, for example, the butterfly valve in -a carburetor. The pivotally mounted lever generally is mounted on a pivot whose axis is transverse to the reciprocal movement of the stem of the control knob. To accommodate the circular path of the end of the lever arm to the reciprocatory motion, a pin and slot mechanism is conventional. However, due to the vibration of the mechanism and repeated actuation of the lever arm, the pin has a tendency, on occasion, to become deformed and to establish unusual wear patterns and occasionally will get hung up so that relative movement becomes difiicult.

This invention is concerned with a structure which solves the aforenoted problems. More particularly, this invention is concerned with a one piece plastic choke control member or the like which may be made in a single molding operation and which is exceedingly easy to assemble both initially and in field repair situations without the use of additional fastening means.

Another object of this invention is to provide a control member which may be inserted from the exterior of the housing through blind apertures in a manner to establish a connection between a member to be controlled which is remote from the housing aperture and in a manner that is relatively easy to assemble and which severely retards unauthorized disassembly.

It is a further object of this invention to provide an assembly which serves the dual functions of providing quick snap on attachment and detent cooperation.

A still further object of this invention is to provide a knob and stem control means which is noncorrosive, is dimensionally stable, withstands weathering well, is durable for its intended purpose, has no sharp corners on those portions which are engageable by the human hand and is otherwise well designed for the purposes for which it is used.

A still further object of this invention is to provide 3,228,254 Patented Jan. 11, 1966 "ice an assembly which provides the dual functions of quick connection and detenti-ng in a manner to eliminate parts and is more economical in materials, and assembly time as compared to prior art assemblies.

Another object of this invention is to provide a control member which is easy to tool in such a manner that the aesthetic portion (the knob portion), may be readily changed to impart a versatility of designs of knob-s while maintaining the functional aspects of the entering end of the stem portion essentially unchanged.

The novel features that are characteristic of the invention are set forth with particularly in the appended claims; the invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood by the following description of specific embodiments when read in connection with the accompanying drawings in which:

FIG. 1 is a semi-diagrammatic view of an assembly utilizing the control means which is the subject of this application;

FIG. 2 is a side elevational view of a portion of the detent mechanism used in the assembly shown in FIG. 1;

FIG. 3 is an enlargement of the upper portion of the detent mechanism shown in FIG. 3;

FIG. 4 is a right hand end view of the mechanism shown in FIG. 2;

FIG. 5 is a bottom plan view of the mechanism shown in FIG. 4;

FIG. 6 is a perspective view of one form of control knob and stem member forming a part of the assembly shown in FIG. 1;

FIG. 7 is a side elevational view of the member shown in FIG. 6, the head portion thereof being modified in nonfunctional respects;

FIG. 8 is a sectional view along lines 88 of FIG. 7;

FIG. 9 is an end view of the member shown in FIG. 7;

FIG. 10 is a top plan view, partially in section, of the member shown in FIG. 7, the head portion being modified to illustrate another variation of the knob design available;

FIG. 11 is a sectional view taken along lines 11-11 of FIG. 10;

FIG. 12 is a view similar to FIG. 1, with certain portions of the assembly being shovm in section to illustrate the snap on attachment features of the assembly;

FIG. 13 is a view showing an alternate method of attachment of a dilferent lever arm to a member such as shown in FIGS. 6 through 12; and

FIG. 14 is a view of an alternate form of member serving substantially the function as the member shown in FIGS. 6 through 11.

Returning now to FIG. 1 of the drawings, an assembly 10 is shown partially in dotted lines and partially in full lines, the dotted lines showing the approximate location of a carburetor for an outboard motor or the like and the full line portions 12 show a plurality of lever arms, springs, detent mechanisms and control knob for a manual choke control. More particularly, link 14 in the form of a wire rod is attached to a butterfly valve member (not shown) and in turn is actuated by a pivotally mounted member 15 which is one arm of a bell crank lever. The other arm 16 of the bell crank lever is springloaded against and actuated by a pivotal lever member 18 which is directly actuated by the control knob means 20.

The control knob means 20 is associated with a detent mechanism 22 to be more particularly described. The knob means 20 may be inserted through an outer casing or housing 24 having a grommet means 26 therein, said knob means being inserted so as to engage the lower arm 28 of pivotal member 18 which has a cam surface 30 on the bottom thereof as shown in FIGS. 1 and 12. The control knob means 20 is inserted through the detent means and through the panel and reciprocates with a straight line motion from left to right and right to left as viewed in FIGS. 1 and 12. The pivot 32, for lever 18, is disposed substantially transversely to the line of motion of the control knob means 20. Thus, lever arm 28 and end surface 30 thereon'follow a circular path around pivot 32 which intersects the path of travel of the knob control means 20.

It will be specifically realized that while this invention is to be discussed in terms of the choke control knob for association with a carburetor and carburetor lever arm, this precise usage is to be considered illustrative only, as the control means 20 has a wider field of application and use.

The detent means 22 may take the form of a plastic member 36 (shown in detail in FIGS. 2 through which is fixed to a portion 34 of the casting which mounts the carburetor means shown in FIG. 1. The plastic member 36 may be made of a material such as nylon and is adapted to be inserted into a hollow, somewhat rectilinearly shaped boss 34, there being stops 38 and ears 40 integral therewith which prevent relative movement of the member 36 to the casting boss 34 after assembly of member 36 thereto. As shown in FIG. 4, the member 36 is split along the bottom side thereof to permit easy insertion into the boss 34, and member 36 is formed with a hollow through bore 42. The two side walls of member 36, defining the bore 42, are substantially parallel to each other so that relative rotation between the shank of the control knob means 20 when the latter is inserted therewithin is prevented. The upper wall of member 36 is formed with a flexible portion 44 having a depending rib 46 which extends transversely of the bore 42. Due to the relative thickness of portion 44, rib 46 may move in a vertcal direction upwardly as viewed in FIGS. 2 and 3. Due to the inherent resiliency of the material of which member 36 is made, the rib 46 will return to or be biased toward the at-rest positions shown in FIGS. 2 and 3. The rib 46 serves as the detent means for coaction with the control knob as will become apparent through later discussion. While a particular detent means 22 has been shown and discussed, any of a plurality of different detent means which will serve the same function is permissible and does not form the basis of this invention except for the cooperation with the knob means 20.

The control knob means 20 has a generally rectilinear shank portion 48 as shown in FIG. 7 with the knob portion 50 of any one of a plurality of configurations, as suitable and desired, at one end thereof and with an entering end means 52 at the opposite end of the shank. Intermediate the two ends of the shank and closely adjacent to the entering end portion 52 is a portion 62 which cooperates with the detent member 36. As shown in FIG. 8, the intermediate portion 62 has substantially parallel opposed side portions 54 and 56, the top surface 58 and bottom surface 60 being substantially transverse to the side walls 54 and 56. Stop means 55 on sides 54 and- 56 prevent over-actuation of knob means 20. As shown in FIGS. 8 and 11, recesses may be made in the essentially rectilinear shank portion to reduce the amount of material in the shank. A curvilinear surface 64 connects two depressed areas 66 and 68 which provide the end limits of the travel of the control knob in detent cooperation with the rib 46 on member 36.

As can be seen in FIG. 11, the center web 70 separates the recesses in a transverse direction and extends to a position just below the right hand detent recess 66. Outboard of the detent receiving portion 66, to the right as viewed in FIG. 11, is a pair of side extensions 72 and 74, which may be spaced apart a slightly lesser dimension than are side walls 54 and 56 as shown in FIGS. 8 and or may be the same as shown in FIG. 6. An extension of center web 70 in the form of an angularly divergent cross web portion 76 which together with an angularly extending front cross web portion 78, the arms 72 and 74, and an upwardly extending web portion 75 define an aperture for receipt of the lever member 30 as shall be explained. The nose portion cross web 78 has a top surface 86 which is spaced slightly below the vertical extent of the two arms 72 and 74. It should be further noted that the arm extensions 72 and 74 have front extension portions 82 and 84 which are beveled as best shown in FIG. 10 and extend beyond web 78.

A resilient hinge rib 88 is formed by the cross web 76 by recessing surface 60 as perhaps best shown in FIG. 11. The structure shown will flex in a downwardly direction around the rib area 88 from the position shown in FIG, 11 in a manner as shall now be explained.

To assemble the knob control means 20, so as to engage the lever arm 28, the control knob means 20 is merely inserted through the panel 24, grommet 26 and through the aperture 42 in the detent member 36. As the entering end portion progresses through the aperture 42, rotation thereof is prevented due to the cooperation of the sides 54 and 56 with the side walls of the detent member 36.

Due to the angle of inclination of the web portion 78 and the beveling 82 and 84 on the side members 72 and 74, the entering end engages and guides the end 30 of lever 28. As the knob means 20 is forced inwardly, the entering end portion 52 is forced downwardly so as to flex about the hinge rib 88. Lever 28 has only a limited range of travel set by other limits so that the rounded end portion 30 coacting with member 78 serves to cam the end portion 52 of the control knob means downwardly until web 78 snaps over the end portion 30 to trap lever 28 in the aperture 80. Once the lever 28 and the control knob means 20 are assembled, as shown in FIG. 12, it is difiicult to disassemble same. The beveled lead in portions 82 and 84 and the short portions of the extensions 72 and 74 above the top surface 86 of member 78 prevent the lever arm 28 from twisting during the downward flexure of the control knob. Once assembled, the control knob may be actuated between its detent position by merely reciprocating same. Obviously, the housing 24 and grommet 26 are not necessary to'the cooperation involved and hence the presence thereof is permissive.

Another type of lever arm 28a is shown mounted to substantially an identical control knob means by being inserted from the other side of the aperture 80. As shown in FIG. 13, the end portion 30a has a rounded portion which is adapted to ride on the back side f the web portion 78 until hook portion 90 engages the top portion 86 thereof. A reverse hook portion 92 on lever arm 28a engages the furthest extent of the web portion 76.

Another embodiment of knob control means 20b is shown in FIG. 14 and serves substantially a similar function. The embodiment shown in FIG. 14 is adapted to flex transversely to the flexure of the member shown in FIG. 11. To this end the entering end portion has a cam surface 94 and a plurality of flexure ribs 96. The lever arm member 28 cams portion 94 downwardly as viewed in FIG. 14 until the lever arm bottoms on the aperture at 106. At this point the thin web 102 will snap over the edge of the arm enclosing and trapping the end of a lever arm similar to lever 28. The member 28 is trapped between the extensions 98 and the web 102 when the device is assembled although it will be realized that there is slightly more lost motion between the movement of the control member formed as shown in FIG. 14 as compared to control members shown in the other figures.

In both embodiments of the invention, a convenient snap on knob control means has been shown which is economical to assemble and manufacture as well as serving to provide a cooperation with a detent mechanism.

Although various embodiments of the invention have been shown and described, it is with full awareness that many modifications thereof are possible. The invention,

therefore, is not to be restricted except as necessitated by the prior art and the spirit of the appended claims What is claimed as the invention is:

1. In combination, a detent mechanism at a fixed location, a lever arm member having an end portion operable for limited movement to and from said fixed location, and a control member connected to said lever arm member, said control member comprising an elongated body having first and second ends, knob means connected with said first end, said elongated body intermediate its first and second ends having a portion of reduced vertical dimension constituting a weakest section for vertical flexure of said elongated body, a recess between said second end and said portion of reduced vertical dimension, and cam means between said second end and said recess, said cam means, when forceably contacted by said end of said lever arm, causing said second end t deflect at said portion of reduced vertical dimension permitting said end of the lever arm to override said cam means and to be engaged in said recess.

2. The combination set forth in claim 1 wherein said detent mechanism is formed with a through aperture for receipt of said control member for relative movement therein and said lever arm member is mounted for limited pivotal movement in a plane coincident with the axis of said through aperture in said detent mechanism.

3. A control member for insertion into an aperture to engage the end of a lever arm operable in a plane substantially transverse to the axis of said aperture comprising an elongated body having first and second ends,

knob means connected with said first end, said body intermediate its first and second ends having a portion of reduced vertical dimension constituting a weakest section for vertical flexure of said elongated body, a recess between said portion of reduced vertical dimension and said second end, and cam means between said second end and said recess, said cam means, when forceably contacted by said end of said lever arm, causing said second end to deflect at said portion of reduced vertical dimension permitting said end of the lever arm to override said cam means and be engaged in said recess.

4. The control member according to claim 3 in which a surface of said elongated body has at least one depression serving as a travel limit for coaction with a detent means.

5. The control member according to claim 3 in which a surface of said elongated body has at least two depressions interconnected by a curvilinear surface, said depressions serving as travel limits for coaction with a detent means.

6. The control member according to claim 3 in which said elongated body is essentially rectilinear in crosssectional area.

References Cited by the Examiner UNITED STATES PATENTS 2,304,356 12/1942 Heller 74527 X MILTON KAUFMAN, Primary Examiner.

Claims (1)

1. IN COMBINATION, A DETENT MECHANISM AT A FIXED LOCATION; A LEVER ARM MEMBER HAVING AN END PORTION OPERABLE FOR LIMITED MOVEMENT TO AND FROM SAID FIXED LOCATION, AND A CONTROL MEMBER CONNECTED TO SAID LEVER ARM MEMBER, SAID CONTROL MEMBER COMPRISING AN ELONGATED BODY HAVING FIRST AND SECOND ENDS, KNOB MEANS CONNECTED WITH SAID FIRST END, SAID ELONGATED BODY INTERMEDIATE ITS FIRST AND SECOND ENDS HAVING A PORTION OF REDUCED VERTICAL DIMENSION CONSTITUTING A WEAKEST SECTION FOR VERTICAL FLEXTURE OF SAID ELONGATED BODY, A RECESS BETWEEN SAID SECOND END AND SAID PORTION OF REDUCED VERTICAL DIMENSION, AND CAM MEANS BETWEEN SAID SECOND END AND SAID RECESS, SAID CAM MEANS, WHEN FORCEABLY CONTACTED BY SAID END OF SAID LEVER ARM, CAUSING SAID SECOND END TO DEFLECT AT SAID PORTION OF REDUCED VERTICAL DIMENSION PERMITTING SAID END OF THE LEVER ARM TO OVERRIDE SAID CAM MEANS AND TO BE ENGAGED IN SAID RECESS.

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