US3670119A

US3670119A - Switch with improved actuator means

Info

Publication number: US3670119A
Application number: US120139A
Authority: US
Inventors: Wallace A Gebhardt; Prentice R Corn
Original assignee: Switches Inc
Current assignee: Federal Mogul LLC
Priority date: 1971-03-02
Filing date: 1971-03-02
Publication date: 1972-06-13
Anticipated expiration: 1989-06-13
Also published as: FR2128531B1; CA950512A; AU3943272A; BR7201217D0; DE2210114A1; GB1371263A; IT952072B; JPS5345567B1; FR2128531A1; AU464328B2; AR193849A1

Abstract

A switching mechanism that is adapted to be incorporated into a seat to sense the presence of an occupant and actuate a switch in response thereto. The switching mechanism includes a switch supported in a housing and having a movable element with an actuating system cooperating with the switch. The actuating system includes an elongated member having one end connected to the support and a free end spaced from the support. The elongated member extends generally parallel to the upper surface of the seat and is deflected from normal in response to an occupant in the seat. An elongated actuating arm cooperates with the element and the free end of the first elongated member to move the element between the first and second positions in response to deflection of the elongated member thereby actuating the switch. The switching mechanism further includes automatic adjustment means to compensate for manufacturing and age variations of the seat.

Description

United States Patent Gebhardt et al. June 13, 1972 [54] SWITCH WITH IMPROVED ACTUATOR 3,375,495 3/1968 Bums... ..340/278 X MEANS 2,276,378 3/1942 Dugvay ..200/l53 V UX [72] Inventors: Wallace A. Gebhardt; Prentice R. Corn, R. Scott both of Logansport, Att0rneyDressler, Goldsmith, Clement & Gordon 73 Assi nee: Switches Incor rated 1 g 57 ABSTRACT [22] Filed: March 2, 1971 A switching mechanism that 18 adapted to be incorporated pp 120,139 into a seat to sense the presence of an occupant and actuate a switch in response thereto. The switching mechanism includes 52 U.S. Cl. ..200/52 R, ZOO/61.58 B a suppcined havlng a 'f [51] Int Cl "01h 35/00 with an actuating system cooperating with the switch. The a.- [58] Field of Search ..200/6l.58 B, 86 R, 86 A, 153 v, mating *g g zf gi f 200/527 6L, 61.42, 6143; 307/10; 340/52 278 connecte tot e support an a ree en space romt e support. The elongated member extends generally parallel to the [56] Refrences Cited upper surface of the seat and is deflected from normal in response to an occupant 1n the seat. An elongated actuating UNIT D STATES PATENTS arm cooperates with the element and the free end of the first elongated member to move the element between the first and 3,109,075 10/1963 Ratcliff ..200/52 Second positions in response to d fl ti f the elongated 2,493,157 1/1950 Merralls et a]. ..200/86 R member thereby actuating the switch The Switching 3,297,841 V1967 Campbell B mechanism further includes automatic adjustment means to 3,281,818 10/1966 Morgan at B X compensate for manufacturing and age variations of the seat. 2,996,587 8/1961 McCarthy ..200/6l.58 B 3,166,146 1/1965 Shaw ..200/61.58 B X 31 Claims, 16 Drawing Figures I7 I I 8 i wil +1, 4

I *1 24 I as SWITCH WITH IMPROVED ACTUATOR MEANS BACKGROUND OF THE INVENTION The present invention relates generally to switches and more specifically to an improved seat sensing switch for use as part of a warning system in an automobile.

With the recent emphasis upon safety in the automobile industry and the entry of a federal government into the field for policing safety, numerous safety and warning devices have been incorporated into present day automobiles. For example, the federal government has recently required that each new automobile sold must incorporate a sufficient number of seat belts to allow at least one seat belt for each occupant of the automobile. While this requirement was readily satisfied by the automobile industry, one of the problems encountered was the fact that the occupants of the vehicle did not use the seat belts in many instances thereby negating the possible elimination of injury in an automobile accident, as was envisioned by the requirement of seat belts.

Thus, the industry and the federal government searched for a solution to at least partially overcome the problem of the occupant neglecting to fasten the seat belt while the automobile is being operated. The solution to this problem appeared to the federal authorities as requiring some type of warning system that would indicate when the occupant was in the seat and the seat belt was not fastened. In addition to the broad encompassing requirement by the federal government, additional specific requirements were made that must be complied with by the auto industry. The auto industry in turn made numerous additional requirements which had to be met by suppliers of the various elements that were needed to comply with the federal regulations.

SUMMARY OF THE INVENTION The present invention contemplates a seat sensing mechanism which includes a switch that will be actuated when the seat is occupied and the occupant fails to fasten the seat belt.

The seat sensing mechanism of the present invention includes a switch having a movable element moved between positions to open and close the switch, which is supported in a housing or support. A switch actuating means moves the element between the positions and includes an elongated member or arm connected to the support with a free end spaced from the support and being deflected between opposite ends from a normal position in response to an occupant in the seat. An elongated strap or actuating arm is connected to the free end of the elongated member and to the movable element to convert the deflection of the elongated member to movement of the element thereby actuating the switch.

According to one specific aspect of the present invention, friction clutch means is incorporated in one of the connections to accommodate relative movement of the connected parts by the subject connection when the movement of the actuator arm is greater than the allowable movement of the actuator. In one embodiment, the actuator is interposed between the adjacent end of the actuator arm and the movable element and a friction clutch interconnects the actuator and the actuator arm and acts as yieldable means to accommodate the relative movement between the actuator and the actuator arm. In an alternate embodiment, the friction clutch is interposed between the opposite end of the actuator arm and the free end of the elongated member or arm while the remaining end of the actuating arm, acting as the actuator, directly engages the movable element. In both embodiments, the friction clutch automatically causes the actuating means to compensate for manufacturing variations and changes induced by use in the contour of the seat.

The switching mechanism further includes first adjustable means for varying the amount of travel of the element between the open and closed positions and a further adjustable means for limiting the amount of travel of the actuator after the movable element is in the closed position.

In its specific embodiment, the elongated member or tension member for the elongated strap is in the form of a spring metal strap that is directly connected to a main body portion of an elongated resinous spacer that has projections extending from one side thereof. The projections cooperate with the elongated strap to maintain the strap and the elongated member, including the steel strap and the main body portion of the resinous spacer in a spaced generally parallel condition at all times.

The seat sensing mechanism further includes a free or lost motion connection between the actuator and the movable element to accommodate relative movement after the element has been moved to its switch closing position. This significant feature allows for the elongated member to be deflected an amount greater than necessary for closing of the movable element and returning to a stable position between the maximum and normal deflected positions to accommodate increases and decreases in forces on the elongated member while the occupant is in the seat without opening the switch.

A further aspect provided by the present invention is an automatic re-adjustment feature to allow for contour variations in manufacturing and changes due to use. The seat sensing mechanism is re-adjusted each time the elongated member is deflected an amount greater than necessary to close the switch. This repositions the actuator causing it to engage the movable element sooner when the deflecting force is removed. When the seat returns to its static position the actuator will be repositioned to provide original contact adjustment.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF DRAWINGS FIG. 1 is a fragmentary perspective view of a seat with the switching mechanism of the present invention incorporated therein;

FIG. 1a is a schematic illustration of the location of the switching mechanism in relation to the seat springs;

FIG. 2 is a schematic illustration of an electric circuit incorporating the switching mechanism;

FIG. 3 is a fragmentary side elevation view of the switching mechanism;

FIG. 4 is a' fragmentary plan view of the switching mechanism;

FIG. 5 is an enlarged fragmentary sectional view taken along line 5-5 of FIG. 3;

FIG. 6 is an enlarged fragmentary horizontal sectional view taken along line 66 of FIG. 5;

FIG. 7 is a plan view, partly in section, of a slightly modified form of the switching mechanism;

1 FIG. 8 is a side elevation view of the switching mechanism shown in FIG. 7;

FIG. 9 is an enlarged fragmentary vertical section taken along line 9-9 of FIG. 7;

FIG. 10 is a fragmentary section similar to FIG. 9 showing the switch in its actuated position;

FIG. 11 is a sectional view on the scale of FIGS. 7 and 8, and taken generally along line 1 l-1 I of FIG. 9;

FIG. 12 is a further sectional view on the scale of FIGS. 7 and 8 and similar to FIG. 1], taken generally along line 12- 12 of FIG. 9;

FIG. 13 is a fragmentary sectional view taken generally along line 13-13 of FIG. 9;

FIG. 14 is a sectional view taken generally along line 14- 14 of FIG. 10; and

FIG. 15 is an end view of the actuating means.

DETAILED DESCRIPTION While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail two specific embodiments, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated.

FIG. 1 of the drawings generally discloses a seat having a back rest' 12 cooperating therewith. The seat includes a thickness of compressible cushioning material that is located between upper and lower surfaces of the seat with spring means 14 extending normally front to back across the seat. The spring means 14 (FIG. 1a) is illustrated as a zigzag spring which consists of a wire that is bent to a sinusoidal configuration and located in a substantially common horizontal plane along the lower surface of the seat. A pair of seat belt portions 16 are attached to the support for the seat and have buckle portions 18 attached to the free ends thereof;

The seat sensing mechanism 20, illustrated in the embodiment of FIGS. 3-6, is specifically designed to be supported directly on the upper surface of the spring 14 and held in a fixed relation thereto, as will be described later. The sensing or switching mechanism 20 includes a switch 21 (FIG. 2) having a fixed contact 22 (FIG. 6) and a movable contact or element 24 that is moved between open and closed or first and second positions to actuate the switch. The respective switch contacts are supported in a housing or support 26 and respectively connected to leads or wires 28 that extend out of the housing and are connected in an electrical circuit 30 that incorporates a second switch 32, a warning device 34'and a suitable source of power 36. In the illustrated embodiment, the movable contact or element 24 is formed of a spring metal material that defines biasing means for normally maintaining the element in the closed position when allowed to close by movement of the actuator 60, to be described later.

Switch actuating means, generally designated as 40, cooperates'with the housing and the spring biased element or contact 24 to move the contact between closed and open positions and actuate the switch in response to deflection of the seat from its normal position. The actuating means is constructed in accordance with the teachings of the present invention and is capable of being deflected an amount greater than that required for actuating the switch to compensate for variations in weight of the occupant as well as variations in forces applied thereto when the occupant initially occupies the seat or moves to vary the fiexture of the actuating means.

The actuating means 40 for moving the element between the two positions extends from the support in a direction generally parallel to the upper surface of the seat 10 and terminates in a free end that is spaced from the support. The actuating means 40 has sufficient'rigidity to remain in a substantially planar, normal condition when no load or weight is supported on the seat or load supporting device but has sufficient resiliency to be deflected to conform to any normal static seat condition between its opposite ends or assume anydeflection required when a load is supported on the seat or device.

The second means or actuator 60 consists of an elongated integral piece of resinous material that has a transversely extending slot or recess 62 adjacent one end thereof. One surface of, the actuator is generally flat and is in contacting engagement with the adjacent surface of the elongated strap 44. According to a primary aspect of the present invention, the interconnection between the actuator and the strap 44 includes a mechanism or friction clutch for frictionally connecting the actuator to the strap in a manner to accommodate relative movement between the actuator and the strap 44 when the strap or elongated member 42 has been deflected beyond a predetermined maximum. The mechanism or friction clutch means 63 is illustrated as including a spring 64 FIG. 5) having one end in engagement with the lower surface of the elongated strap 44 and its opposite end in engagement with an enlarged head 66 of a rivet or other suitable means 68 that extends through an elongated slot 70 in the strap 44 and has its upper end secured to the actuator 60. In connecting the rivet or other suitable securing device 68 to the actuator, the spring 64 is compressed sufficiently toproducea friction connection between the strap'and the actuator. The actuator and friction clutch means define an operative connection between the element 24 and the actuating arm or strap.

The actuating means, and more specifically the actuator 60, further includes a first portion 72, defined by one side wall of the recess 62, engaging an adjacent surface of the element to hold the element 24 in the switch open position and allow movement ofthe element to the switch closed position when the elongated member or resilient arm is moved from its normal to its deflected position, as will be described later. The actuator 60 also includes a second'portion 74, between the op- The actuating means 40 includes a first elongatedsheet metal strap or arm 42 that has one end connected to the housing 26 and a free end 43 spaced from the housing. The actuating means further includes means or a second elongated'strap or actuating arm 44 that extends generally parallel to the first arm and has one end cooperating with the switch element 24 and a free end cooperating with the free end of the first arm or strap 42 to actuate the switch in response to deflection of the straps or arms between opposite'ends. Preferably, the straps are maintained in a generally parallel spaced condition relative to each other, by a spacer 48 which includesa substantially continuous portion 50 of a resinous plastic material that is held in direct contacting engagement with the metal strap 42. The spacer 48 'has a plurality of longitudinally spaced spacer means 52 extending from the exposed surface thereof towards the elongated spring metal strap 44.'The free or outer ends of the

straps

42, 44 and the spacer 48 are held in a fixed relation to each other by a rivet 54. The rivet or first means 54 defines an operative connection between the straps at a location spaced from the housing 26 and more specifically adjacent the free ends of the straps.

The switch actuating means 40 further includes second means or an actuator 60 cooperating with the end of the strap 44 adjacent the housing to operatively connect the strap to the movable element in a manner which will now be described.

hereinafter.

posite side wall of the recess 62 and the free end of the actuator to provide a mounting for threaded stud and stop for an adjusting screw v90. The spacing between the respective side walls of the recess is greater than the thickness of the movable element to define a free motion connection that accommodates movement between the element and the actuator when the element is in its closed position. The purpose of the free motion connection will be described According to a further aspect of the invention, the actuator incorporates adjustable means for varying the extent of free motion movement between the element and the actuator. This adjustable means is in the form of a screw'80 threaded into an opening in the second portion 74 of the movable plastic actuator 60. The screw'or threaded stud 80 extends through an enlarge'd opening 82 in the housing or support 26 and receives a nut 84 on the outer end thereof. The nut 84 engages the outer surfaces of the housing 26 upon a predetermined amount of movement of the actuator 60 relative to the housing and prevents further longitudinal movement of the actuator. The extent of movement of the actuator after the element 24 is in the dotted line position shown in FIG. 6 is set by adjustment of the nut, as will be described later. i

The actuating means of switch 20 further includes a sensitivity adjustment for varying the sensitivity of the entire device. This sensitivity adjustment is in the form of a set screw threaded into an opening in the housing or support 26 with the inner end of the set screw or adjustment screw disposed in the path of movement of the actuator 60. The rotation of the screw 90 will determine the extent of travel of the actuator as the switch element 24 is moved between closed and open positions and can be adjusted to vary the amount of travel of the movable element 24 between its closed and open positions, respectively shown by the dotted and solid lines of FIG. 6.

The operation of the sensing mechanism will now be described. Theswitching mechanism 20 is inserted in the seat between the upper surface of the spring and the lower surface of the cushioning material with the wire spring 14 being received in a recess92 defined between spaced

housing portions

94 and 96. Therernainder of the switching mechanism consisting of the actuating means or system lies on top of the spring and is held in a position generally parallel to the upper in more detail surface of the seat by having the cushioning material in direct contact therewith or other suitable means.

In its initial position, the switch actuating means 40, including the two straps or

arms

42 and 44, and the spacer 48 and the actuator 60 is in a substantially planar normal condition and the movable element or contact 24 is held in its open position, shown by the solid line position of FIG. 6, by cooperative engagement of the first portion 72 of the actuator 60 with the element 24. If an occupant should occupy the seat, the weight thereof will cause a compression of the cushioning material and transmit forces in a direction generally perpendicular to the elongated strap or actuating arm 44, through the strap supporting arm 42 and the spacer 48, to cause the elongated actuating arm 44 to deflect downwardly between its opposite ends. This downward deflection is converted to linear movement of the actuator 60, through the longitudinal movement of the adjacent end of the actuating arm 44 relative to the support or fixed portion because the outer ends of the straps and spacer are fixed to each other. By having the lower strap 44 spaced below the upper strap 42 and maintained in a generally parallel condition at all times, through the spacer 48, deflection of the upper strap from its normal planar condition to a curved configuration will move the first portion 72 of the actuator away from the contact and allow the biasing means incorporated into the contact or element 24 to move the element to its closed position.

Once the element or switch contact 24 is in the closed position, it is desirable to accommodate further movement of the strap or actuating arm 44 and actuator 60 a predetermined distance to allow some return deflection of the actuating means without opening the switch 21. This is desirable since, when a person initially sits down on the seat, an initial maximum force will be transmitted to the cushioning material to deflect the cushioning material and the actuating 'means an amount greater than required for supporting the occupant. After the occupant is seated, the seat and spring will assume an equilibrium condition in which the deflection or compression of the cushioning material and the spring 14 is somewhat less than the maximum force or deflection initially encountered during the period when the person is sitting down. This variation is absorbed by the free motion connection between the actuator and the element so that the element remains in its closed position when the equilibrium condition of the cushioning material has been reached. The amount of free travel between the actuator and the element or contact 24 is set by adjusting the nut 84 relative to the housing or support 26. In addition, the adjustment screw 90 determines the extent of travel of the element 24 between its open solid line position and closed dotted line position of FIG. 6 and thereby adjusts the sensitivity of the switching mechanism.

Assuming that the switching mechanism has just been installed in an automobile and the sensitivity of the switch and the amount of free travel between the actuator and the element 24 have been set, the seat sensing mechanism is designed to automatically compensate for a variety of conditions by incorporation of the friction clutch 63. If a person sits down on the seat, the seat spring 14 will be deflected proportional to weight applied and deflect the switch actuating means 40 between its opposite ends into an arcuate configuration. The operative connections between the arms, the housing, and the element will convert the deflection or flexing of the arms to produce longitudinal movement of the actuating arm relative to the housing or fixed portion. By having the elongated strap 44 spaced from the tensioning strap 42 with the inner end guided for movement on the support or housing, the switch will be actuated with a minimum amount of deflection which will be transmitted through the operative connections to allow the spring biasing of the element 24 to move to a position cor-' responding to the closed position of the switch. After the switch is in the closed position, further deflection of the

elongated members

42, 44 is accommodated without movement of the element 24 by the free motion connection between the actuator 60 and the element 24. After the nut 84 engages the outer surface of the support or housing 26, further movement of the actuator is prevented. Thereafter, any further downward deflection of the upper strap 42 and consequent downward deflection of the lower strap 44 between its opposite ends will overcome the frictional connection or means in the operative connection between the actuating arm and the actuator, produced by the friction clutch 63 between the actuating arm and the actuator to increase the effective length of the strap. It should be noted at this point that the biasing force of the spring 64 must be greater than the biasing force of the movable element 24 in order to accomplish this goal. Stated another way, the friction connection must permit relative movement between the actuator and the actuating arm when the switch is closed and the travel of the adjacent end of the actuating arm in the switch closing direction is greater than the permitted movement of the actuator.

After its initial maximum deflection, the seat 10 and spring 14 will reach an equilibrium condition, in which the two

portions

72 and 74 of the actuator 60 will, in most instances, be spaced from the contact or element 24 so that the element is biased and held in its closed position solely by the biasing force incorporated therein.

Assuming that the operator then gets off the seat, the inherent tendency for-the actuating means 40, including the

straps

42, 44 and the spacer 48, will tend to return to their flat planar condition. This action is assisted by the tendency for the zigzag spring to also move to its normal condition. The flexibility of the switch actuating means 40 will allow it to assume the normal condition of the seat spring 14. During such movement or return from the deflected to the normal position, the first portion 72 of the actuator will engage the movable element 24 and move theelement from its closed to its open position. After having moved to the open position, defined by the adjustment screw 90, further movement of the actuator 60 is prevented. Should the elongated strap 44 require further movement to return to its normal position, this movement will again cause relative movement of the inner end of the strap towards the actuator 60 while the actuator remains in its fixed position to automatically readjust the switch actuating means. It should be noted at this point, during upward movement of the strap 44 to a normal condition, the forces produced by the biasing means incorporated into the element 24 will assist in overcoming the frictional force developed by the spring 64 so that only a minimum amount of additional force need be developed to produce relative movement between the strap and the actuator.

The self-adjusting feature between the actuator and the strap allows for the switching mechanism to automatically compensate for permanent changes in the contour of the seat. For example, assuming that the car has been in use for some time, the seat spring may have a tendency to sag from its normal condition and remain in a sagged condition without any weight being applied or supported on the upper surface thereof. The switching mechanism would automatically adjust itself to accommodate such changes in configuration of the seat and still remain as sensitive as it initially was when installed into the automobile. If desired, the function of the adjustment nut 84 and reset adjustment screw 80, as well as set screw 90, could be achieved by proper dimensioning of the length of the actuator 60 and the adjacent mating surfaces of the housing 26 with this arrangement the opposed inner surfaces of the housing would act as fixed stops defining the extent of travel of the actuator.

A slightly modified form of the present invention is disclosed in FIGS. 7-15 wherein several of the features described above have been deleted to simplify the construction of the switching means. The switching means is specifically designed for being incorporated into the cushioning material of the seat adjacent the upper surface thereof.

The switching means or mechanism 100 again includes a switch (FIG. 13) consisting of a fixed contact or element 102 and a movable contact or element 104 that incorporates biasing means for normally maintaining the contacts in the closed or second position shown in FIG. 10.

The switch mechanism 100 further includes switch actuating means 106 (FIG. consisting of a strap or elongated arm 108 of spring metal and a spacer 110 including a main body portion 112 that is substantially coextensive in length and width with the strap 108 and has a plurality of longitudinally spaced projections 114 extending away from the free surface thereof. The projections 114 define spacers and some of the spacers have slots or recesses 116 while other of the spacers have openings 118. The openings 118 are in'longitudinal alignment with the bottoms of the recesses or slots 116, for-a purpose which will be described later.

In the embodiment illustrated in FIGS. 7-15, the elongated lower strap or actuating arm is in the form of a wire 120 that extends through the openings 118 and is received into the bottoms of the recesses 116. As in the previous embodiment, the spacers thus maintain the wire or elongated strap 120 in a generally parallel condition to the elongated member at all times. The outer or free end of the wire 120.extends through an opening, 122 in the free end portion 124 of theresinous plastic spacer 110. The end of the wire is preferably flattened or, as shown, of has a flat small plate 126 fixedly secured thereto. The end portion of the outer free end 124 of the spacer1l0 has a segment 128 cut away to expose the lower surface of the plate 126. The operative interconnection is between the bowed spring clamp 130 that encompasses the end portion 124 and the plate 126 affixed to the spring metal strap or arm 108 that'is received into the cutout segment 128 providing frictional engagement between elements. In addition, the strap 108 and spacer 110 are interconnected at the outer or free end by a rivet 132. Thus, the bowed spring clamp 130 provides an operative connection that produces a frictional force between the free end of the strap 120 and the ad.- jacent end of the tension member, including strap 108 and spacer 110. The entire actuating means 106 is preferably enclosed in a flexible sheath or casing 136.

The inner end of the wire 120 is supported for relative movement on the housing or fixed portion by extending through an opening 140 defined in the support or housing 150 enclosing the switch and is of sufficient length to hold the movable element 104 in its open position shown in FIG. 9 when the'actuating means 106 is in a substantially planar condition. Preferably, the inner end of the wire 120 has an operative connection to the element 104 which includes an enlarger bulb or actuator 142 threaded on the free end to produce the butting engagement with the switch element 104. The bulb 142 is received in a recess or enlarged bore 144, the inner end of which provides an abutment to define the extent of free travel of the. wire after the switch has been closed.

In the embodiment illustrated in FIGS. 7-15, the adjustable stop 90 controlling sensitivity has been replaced by a fixed stop or projection 152 which defines the open position for the movable element 104.

It is believed that the description of the operation of the modified embodiment need only briefly be summarized since it is substantially identical to the operation of the embodiment previously described. During initial deflection of the actuating means 106, the bulb 142 and the wire 120 move away from the element 104 and allows the element to move to its closed position. A predetermined amount of free travel is incorporated into the mechanism after the switch has been closed and is defined by the position of the bulb 142 and the depth of the bore 144. After the bulb 142 engages the inner endof the bore 144, any further deflection of the actuating means 106 overcomes the friction connection in the operative connection between the plate 126 and spacer 108, produced by the spring clamp or friction clutch 130, to accommodate relative movement between the outer ends of the

straps

108 and 120.

In both illustrated embodiments, the circuit 30 is defined to give a visual and/or audio signal when the seat is occupied and the occupant fails to place the seat belt around him and fasten the buckle. The switch 32 is closed when the seat belt is not buckled while the switch 21 is open when the seat is unoccupied so that the switch 21 closes when a person occupies the seat to produce a signal untilfthe seat belt is buckled around the person. However, various other circuits may be utilized to perform the same function. a

While the metal straps 42, 108 and

spacers

48, 110 have been shown as separate pieces in both embodiments, they could readily be incorporated into one piece. For example, the function of the strap 108 could be performed by the main body portion 112 or the spacer 110. Also, if desired, the two arms and spacers could be molded as an integral piece to maintain a proper spacing between upper and lower continuous portions while accommodations relative longitudinal movement or many other combinations to achieve the same desired action.

Furthermore, while the lower arm has been described as the activating arm throughout the description, it is recognized that the same function can be performed by using the upper arm as the actuating arm while using the lower arm as the tension member.

The actuating system for the switch is extremely simple but the unique arrangement of parts and the operative interconnection between the various parts allows the switching mechanism to be initially incorporated into the seat and thereafter automatically compensate for numerous changes in the condition of the seat. The operative interconnections automatically accommodate relative movement of certain parts after the switch has been closed and a deflection greater than the switch closing deflection is applied to the arms in the switch closing direction.

We claim:

1. In a switching mechanism including a switch having an element movable between firstandsecond positions to open and close said switch and a housing supporting said switch, switch actuating means for moving said element and comprising' an elongated arm having a first portion cooperating with said element and a second portion extending away from said housing; an elongated tension member connected to said housing; means maintaining at least a portion of said tension member spaced from said elongated arm; means connecting said tension member to the second portion of said elongated arm for normally maintaining said arm in a substantially planar initial condition and deflecting said arm in response to forces applied in a direction generally perpendicular thereto to cause said elongated arm to move longitudinally relative to said housing, so that said first portion of said elongated arm causes said element to move to said second position and actuate said switch.

2. A switching mechanism as defined in claim 1,'in combination with a seat having cushioning material between upper and lower surfaces thereof and compressible in response to a load being supported on said upper surface, said switch actuating means extending generally parallel to said upper surface and below said upper surface so that a load on saidupper surface will deflect the second portion of said elongated arm and actuate said switch.

3. The combination as defined in claim 2, in which said element includes biasing means biasing said element towards said second position and a lost motion connection between said element and said elongated arm, said lost motion connection accommodating independent movement of said elongated arm when said element is in said second position.

4. The combination as defined in claim 2, further including an actuator on the first portion of said elongated arm adjacent said element, said actuator cooperating with said element to define said lost motion; yieldable means defining a friction connection between said actuator and the first portion of said elongated arm; and means defining a fixed connection tension member, said yieldable means accommodating relative movement between said arm and said tension member when said arm is deflected beyond a predetermined maximum and in which said first portion of said elongated arm is provided at an opposite end of said arm in butting engagement with said element when said tension member is returned to the normal position to move said element from said second to said first position.

6. A switching mechanism as defined in claim 1 wherein said tension member is defined by an elongate strap and an elongate spacer member located between said strap and said elongated arm.

7. A switching mechanism as defined in claim 6 wherein said spacer member maintains said strap in spaced parallel relationship with respect to said elongated arm throughout their respective lengths.

8. A switching mechanism as defined in claim 7 wherein said strap and said actuating arm are thin, flat members. I

9. A switching mechanism as defined in claim 1 in which the first portion of the elongated arm that cooperates with the movable element of the switch is an end portion of said arm.

10. In a switching mechanism including a switch having an element movable between first and second positions to open and close said switch and a housing supporting said switch, switch actuating means for moving said element and comprising an elongated arm having one end cooperating with said element and extending away from said housing; and an elongated tension member connected to said housing and cooperating with said elongated arm, said tension member normally maintaining said arm in a substantially planar normal condition and deflecting said arm in response to forces applied in a direction generally perpendicular thereto to cause said element to move to said second position and actuate said switch, said elongated arm having first means operatively connecting one end thereof to said free end of said tensioning member and second-means operatively connecting the opposite end of said arm to said movable element, one of said first and second means including yieldable means for accommodating relative movement between connected parts in response to deflection of said elongated member beyond a predetermined maximum. 1

11. A switching mechanism as defined in claim 10, in which said first means includes a friction clutch frictionally interconnecting the free end ofsaid tension member and said arm, said friction clutch defining said yieldable means.

12. A switching mechanism as defined in claim 10, in which said second means includes an actuator cooperating with said element and said yieldable means includes a friction clutch frictionally connecting said actuator to said elongated arm.

13. A switching mechanism as defined in claim 10, in which said second means includes a lost motion connection accommodating relative movement between said arm and element when said element is in a second position and said arm is deflected beyond that required to move said element to said second position.

14. A switching mechanism as defined in claim 13, further including adjustable means for varying the extent of relative movement between said arm and element.

15. A switching mechanism as defined in claim 10, further including adjustable means cooperating with said element for varying the amount of travel of said element between said positions to vary the sensitivity of said switch.

16. In a load supporting device having a compressible cushioning material between upper and lower surfaces thereof, a sensing mechanism cooperating with said device and including a switch having an element movable between positions to open and close said switch, a support for said switch; and actuating means for moving said element between said positions, said actuating means comprising: an elongated resilient arm connected to said support, said resilient arm extending from said support in a direction generally parallel to and below said upper surface of said device; an elongated actuating arm extending generally parallel to said resilient arm;

means maintaining said arms spaced from one another; a first operative connection between one end of said actuating arm and said element for moving said element in response to longitudinal movement of said one end of said actuating arm; and a second operative connection between said arm at a location spaced from said first operative connection; said arms being deflectable between opposite ends in response to a load on said device to cause said actuating arm to move longitudinally relative to said support so that the operative connection between said one end of said actuating arm and said element is effective to actuate said switch.

17. A load supporting device as defined in claim 16, in which said element includes biasing means normally biasing said element to close said switch; and adjustable means cooperating with said actuating means for varying the spacing between said open and closed positions to vary the sensitivity of said switch, the further improvement of yieldable means in one of said first and second operative connections in response to deflection of said arms to accommodate relative movement of parts interconnected by said one of said connections when said switch is closed and said arms are deflected.

18. A load supporting device as defined in claim 17, in which said yieldable means includes friction clutch means in said second operative connection between said arms; and in which said one end of said actuating arm engages said element and moves said element between said positions to open said switch when said resilient arm is moved from its deflected to its normal position, the further improvement of a resilient casing enclosing said resilient arm and said actuating arm.

19. A load supporting device as defined in claim 17, in which said first operative connection includes an actuator between said actuating arm and said element with said yieldable means comprising friction clutch means between said actuating arm and said actuator, said actuator having a first portion engaging said element to move said element from a switch closing to a switch opening position when said resilient arm is moved from its deflected to its normal position, said actuator having a second portion engaging said element when said resilient arm is moved beyond a predetermined maximum deflected condition to cause relative movement between said actuator and said actuating arm and increase the effective length of said actuating arm, said portions being arranged to define a lost motion connection between said actuator and said element after said element is moved to a closed position.

20. A load supporting device as defined in claim 19, further including an adjustment screw on said support and having a free end disposed in the path of movement of said actuator, said adjustment screw limiting the extent of movement of said element to define the sensitivity of said switch.

21. A load supporting device as defined in claim 16, further including spacer means between said arms for maintaining said arms generally parallel during deflection.

22. An actuating system for a switch mechanism that includes a fixed support and a movable element mounted on said fixed support and positionable in first and second positions to open and close said switch mechanism, comprising: an elongated actuating arm; a supporting connection between said arm and said fixed support accommodating longitudinal movement of said arm; an operative connection between the movable element and the actuating arm for opening and closing said switch in response to longitudinal movement of said arm; a further arm extending substantially parallel to said actuating arm; a first connection between said further arm and said fixed support; a second connection between said further arm and said actuating arm, said connections and arms cooperating to produce longitudinal movement of said actuating arm relative to said fixed support when a switch closing force is applied to said arms and means in one of said connections to permit relative movement of parts interconnected by said one of said connections when a force is applied to said arms after said switch is closed.

23. An actuating system as defined in claim 22, in which said operative connection includes an actuator cooperating with said element and in which said means in one of said connections is a friction Connection between said actuator and said actuating arm; and in which said first and second connections are fixed connections.

24. An actuating system as defined in claim 22, in which said first connection is a fixed connection and said means in one of said connections is a friction connection defining said second connection between said arms at a location spaced from said support.

25. A switch comprising: a support, a first contact mounted at a fixed location on said support; a second contact carried by said support and movable toward and away from said first contact; and actuating means for controlling movement of said second contact and including a first arm secured to said support and having a portion extending outwardly therefrom, said first arm being flexible whereby said first arm deflects from a normal position to a deflected position when a force is applied thereto, said actuating means further including a second arm having a contact moving portion positioned adjacent said second contact, said second arm having a further portion ex-- tending outwardly from said support and connected to said first arm, means maintaining said second arm in spaced relationship with respect to said first am and supporting said second arm for movement longitudinally relative to said first arm, said second arm being flexible whereby said first and second arms form a deflectable unit when a force is applied to said first arm, the connection between said first and second arms giving said second arm a component of motion longitudinally of said first arm and relative to said support upon deflection of said unit so that the contact moving portion of said second arm is moved relative to said second contact for movement of said second contact in one direction relative to said first contact; and resilient means urging said unit from said deflected position to said normal position whereby the contact moving portion of said second arm is moved relative to said second contact for movement of said second contact in a direction opposite to said first direction.

26. A switch as defined in claim 25 wherein said first arm is an inherently resilient member which defines said resilient means.

27. A switch as defined in claim 25 wherein said means maintaining said first arm in spaced relationship with respect to said first arm includes a spacer located between said arms and retaining said arms in spaced parallel relationship with respect to one another throughout their respective lengths.

28. A switch as defined in claim 25 wherein said arms are thin, flat straps.

29. A switching mechanism as defined in claim 10, further including adjustable means on said housing and located in the path of movement of said second means to vary the sensitivity of said switch.

30. A switching mechanism as defined in claim 12, further including adjustable means carried by said housing and located in the path of movement of said actuator, said adjustable means adjusting the extent of travel of said actuator after said element is moved from its closed position.

31. A switch as defined in claim 25, in which said first contact is immovably mounted on said support.

UHLILJU OLIxLu-J IJLLLJLL \JLL'LuLJ I CERTIFICATE 0F CORRECTION Patent No. 3, 70,119. Dated June 13,1972

Inventofls) Wallace A. Gebhardt ahd Prentice R. Corn It 1e pertificd that error appears in the above-identified patent and that seid Letters Patent are, hereby corrected as shown below:

Column 8,-line62, the number "2" should be -3--.

Column 10, line 5-, "arm'" should be ---arms.

; Signed and sealed this 25th day of December 1973.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents I" OHM PO- $050 "OJ-5) QERTlFICATE or CORRECTION Patent No. 34670.119- taxed June 13;, 1972 InventorCs) Wallace A. Gebhardt and Prentice R. Corn It 15 certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 8, line'62, the number "2"- should be -3--.

Column 10, line 5-, "arm'" should be -arms.

;Signed and sealed this 25th day of December 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents

Claims

1. In a switching mechanism including a switch having an element movable between first and second positions to open and close said switch and a housing supporting said switch, switch actuating means for moving said element and comprising an elongated arm having a first portion cooperating with said element and a second portion extending away from said housing; an elongated tension member connected to said housing; means maintaining at least a portion of said tension member spaced from said elongated arm; means connecting said tension member to the second portion of said elongated arm for normally maintaining said arm in a substantially planar initial condition and deflecting said arm in response to forces applied in a direction generally perpendicular thereto to cause said elongated arm to move longitudinally relative to said housing, so that said first portion of said elongated arm causes said element to move to said second position and actuate said switch.

2. A switching mechanism as defined in claim 1, in combination with a seat having cushioning material between upper and lower surfaces thereof and compressible in response to a load being supported on said upper surface, said switch actuating means extending generally parallel to said upper surface and below said upper surface so that a load on said upper surface will deflect the second portion of said elongated arm and actuate said switch.

4. The combination as defined in claim 2, further including an actuator on the first portion of said elongated arm adjacent said element, said actuator cooperating with said element to define said lost motion; yieldable means defining a friction connection between said actuator and the first portion of said elongated arm; and means defining a fixed connection between the free end of the second portion of said elongated arm and said tension member, said yieldable means accommodating relative movement between said actuator and said arm when said arm is deflected beyond a predetermined maximum.

5. The combination as defined in claim 2, further including yieldable means defining a friction connection between the free end of the second portion of said elongated arm and said tension member, said yieldable means accommodating relative movement between said arm and said tension member when said arm is deflected beyond a predetermined maximum and in which said first portion of said elongated arm is provided at an opposite end of said arm in butting engagement with said element when said tension member is returned to the normal position to move said element from said second to said first position.

8. A switching mechAnism as defined in claim 7 wherein said strap and said actuating arm are thin, flat members.

10. In a switching mechanism including a switch having an element movable between first and second positions to open and close said switch and a housing supporting said switch, switch actuating means for moving said element and comprising an elongated arm having one end cooperating with said element and extending away from said housing; and an elongated tension member connected to said housing and cooperating with said elongated arm, said tension member normally maintaining said arm in a substantially planar normal condition and deflecting said arm in response to forces applied in a direction generally perpendicular thereto to cause said element to move to said second position and actuate said switch, said elongated arm having first means operatively connecting one end thereof to said free end of said tensioning member and second means operatively connecting the opposite end of said arm to said movable element, one of said first and second means including yieldable means for accommodating relative movement between connected parts in response to deflection of said elongated member beyond a predetermined maximum.

11. A switching mechanism as defined in claim 10, in which said first means includes a friction clutch frictionally interconnecting the free end of said tension member and said arm, said friction clutch defining said yieldable means.

16. In a load supporting device having a compressible cushioning material between upper and lower surfaces thereof, a sensing mechanism cooperating with said device and including a switch having an element movable between positions to open and close said switch, a support for said switch; and actuating means for moving said element between said positions, said actuating means comprising: an elongated resilient arm connected to said support, said resilient arm extending from said support in a direction generally parallel to and below said upper surface of said device; an elongated actuating arm extending generally parallel to said resilient arm; means maintaining said arms spaced from one another; a first operative connection between one end of said actuating arm and said element for moving said element in response to longitudinal movement of said one end of said actuating arm; and a second operative connection between said arm at a location spaced from said first operative connection; said arms being deflectable between opposite ends in response to a load on said device to cause said actuating arm to move longitudinally relative to said support so that the operative connection between said one end of said actuating arm and said element is effective to actuate said switch.

25. A switch comprising: a support, a first contacT mounted at a fixed location on said support; a second contact carried by said support and movable toward and away from said first contact; and actuating means for controlling movement of said second contact and including a first arm secured to said support and having a portion extending outwardly therefrom, said first arm being flexible whereby said first arm deflects from a normal position to a deflected position when a force is applied thereto, said actuating means further including a second arm having a contact moving portion positioned adjacent said second contact, said second arm having a further portion extending outwardly from said support and connected to said first arm, means maintaining said second arm in spaced relationship with respect to said first arm and supporting said second arm for movement longitudinally relative to said first arm, said second arm being flexible whereby said first and second arms form a deflectable unit when a force is applied to said first arm, the connection between said first and second arms giving said second arm a component of motion longitudinally of said first arm and relative to said support upon deflection of said unit so that the contact moving portion of said second arm is moved relative to said second contact for movement of said second contact in one direction relative to said first contact; and resilient means urging said unit from said deflected position to said normal position whereby the contact moving portion of said second arm is moved relative to said second contact for movement of said second contact in a direction opposite to said first direction.

28. A switch as defined in claim 25 wherein said arms are thin, flat straps.