US3821504A

US3821504A - Safety switch for snowmobiles and the like having flexible operating part detachable from switch housing by cord

Info

Publication number: US3821504A
Application number: US00130958A
Authority: US
Inventors: K Schomaker; H Shontz
Original assignee: NW Controls Inc
Current assignee: NW Controls Inc
Priority date: 1971-04-05
Filing date: 1971-04-05
Publication date: 1974-06-28
Anticipated expiration: 1991-06-28
Also published as: CA956352A

Abstract

AN INTERLOCKING SAFETY DEVICE FOR USE IN THE OPERATING CIRCUIT OF MACHINERY SUCH AS A SNOWMOBILE OR SIMILAR EQUIPMENT. THE DEVICE INCLUDES SEPARABLE COUPLING MEMBERS, ONE OF WHICH IS A BALL-SHAPED ELEMENT AND THE OTHER A SOCKET-SHAPED ELEMENT WHICH MUST BE INTERFITTED FOR OPERATION OF THE MACHINERY. ONE OF THE COUPLING MEMBERS IS DESIGNED TO BE FASTENED TO THE OPERATOR OF THE EQUIPMENT. UPON SEPARATION OF THE COUPLING ELEMENTS THE POWER SOURCE FOR THE EQUIPMENT IS IMMEDIATELY STOPPED.

D R A W I N G

Description

United States Patent 1191 Schomaker et a1.

Assignee: N. W. Controls, Inc.,'Vernfie1d, Pa.

Filed: Apr. 5, 1971 App]. No.: 130,958

[52] US. Cl. 200/52 R, 200/161, 200/172 R 1 [58] Field of Search 200/51.09, 5l.l, 16 A,

200/6l.08, 61.62-61.93, 172, 52 R, DIG. 2, 161

Int. Cl. I-I0lh 117/08 2,719,898 10/1955 Allen 200/172 A 3.1217711 2/1964 Sander et .11.... 200/172 A 3,142,744 7/1904 Keck 200/172 A 3.175.420 3/1965 Craig 200/172 A x 3.581.037 5/1971 Schiffclbein 2011/172 A Primary Examiner-J. R. Scott Attorney, Agent, or FirmSynnestvedt & Lechner 5 7 ABSTRACT An interlocking safety device for use in the operating circuit of machinery such as a snowmobile or similar equipment. The device includes separable coupling members, one of which is a ball-shaped element and the other a socket-shaped element which must be interfitted for operation of the machinery. One of the coupling members is designed to be fastened to the operator of the equipment. Upon separation of the l 56] References- Cited coupling elements the power source for the equipment 1 f d t] t 0.

UNITED STATES PATENTS e y S Oppe 3.103.130 9/1963 Gunter, Sr. 200/172 A 3 8 Drawing Figures 3,190,982 6/1965 Woodcock 200/61 81 2,607,866 8/1952 Fruh ZOO/61.93

/9 2.9 If 2? J0 12/ 1 *2 I 4'2 i /77777, i W 7 25 J2 g PATENTEDJum rm SHEET 2 0F 2 wg w E m T H m n Qu SAFETY SWITCH FOR SNOWMOBILES AND THE LIKE HAVING FLEXIBLE OPERATING PART DETACHABLE FROM SWITCH HOUSING BY CORD BACKGROUND OF THE INVENTION 1. Field of Invention This invention relates to a safety interlocking device of a kind capable of use in the ignition system of small, self-propelled vehicles and in the operating circuit of various other types of equipment which may present a safety hazard when left running and not under the control of the operator.

2. Description of the Problem and the Prior Act Various types of lightweight, open vehicles such as snowmobiles, dune buggies and the like are used in rather rugged, often hilly, wooded terrain where hidden obstacles are frequent. Because of this fact and the rather carefree way in which these vehicles tend to be used, spills and other accidents frequently occur. In the event of an accident, the operator is likely to be thrown from the vehicle, with the motor running and in gear.

- It is obvious that the fact that the motor is running and the vehicle under power creates an added unnecessary safety hazard, both to the operator and to persons in l the neighborhood. Even if no one is injured, the vehicle is liable to be seriously damaged or at least to run some distance before it comes to a stop.

, The fact that the operator is no longer holding the throttle open doesnt materially diminish the problem as the vehicle can run an appreciable distance when in gear, especially if the engine has a high idle speed or if it is choked as may be the, case in cold weather. Moreover, carburetor icing in cold damp weather can freeze the throttle in an open position after a long run at a steady speed, allowing the vehicle to continue on out of control after an accident.

Another example 'of a kind of hazard which the invention will alleviate occurs because many lightweight vehicles do not have a clutch and'start moving as soon as the brake is released. This tends to produce jerk starts whichmay throw an unwary operator backwards with the result that he loses control of the vehicle, which may run into something before the operator recovers.

Other examples of extremely hazardous situations which are created by small power tools, lawnmowers, tractors and the like when an operator loses control will occur to anyone having experience with that kind of equipment. 7

Even though the need is great, to the best of my knowledge there is no deviceon the market which stops a vehicle of this kind in the event that an accident occurs which causes the operator to lose control of the equipment. Occasional suggestions for safety devices such as the railroad engine deadman throttle, have appeared in the prior art, but devices of this kind are impractical and unduly expensive if used on vehicles and equipment of the type described, and at the least would be inconvenient to the operators of small sport vehicles, such as snowmobiles and dune buggies. Although notlimited thereto, my invention is well adapted for use on the aforementioned kinds of vehicles, as well as tractors, self-propelled lawn mowers and stationary equipment where safe practices required that the operequipment is running.

3. Summary of the Invention and Objects With the foregoing in view an important object of the invention is the provision of a safety device for stopping and preventing further operation of a vehicle or other piece of equipment in the absence of the operator.

Yet another object of the invention is the provision, in combination with a switch, of a separable coupling for controlling the operation of a switch, in which separation effects operation of the switch.

Still another object is the provision of a separable coupling which releases when a separating force is applied to one of the coupling parts through a wide angle of application.

A related object of the invention is the provision of an interlocking device, connectible to the operator of a vehicle or other piece of machinery, for shutting off the power in the event that the operator is thrown from or otherwise leaves the machinery.

A still further object of the invention is the provision of a switch controlling interlock type of safety device of a kind having a pair of interconnectible parts which must be kept in connected relationship for operation of the equipment provided with the interlock.

The above and'other objects of the invention which will appear hereinafter, are achieved by a pair of separable coupling parts one of which is mounted on a vehicle or other piece of machinery and the other of which is adapted to be tied to the operator of the machinery. The coupling parts are separable by the application of a predetermined amount of pulling force, which force is applicable through a wide angle of application around the axis of the coupling. Thecoupling parts must be assembled for operation of the machinery and include means for stopping operation of the machinery when the coupling parts are separated.

As suggested above, the invention is useful for the control of the operation of a large number of different kinds of vehicles and other types of machinery. It is further to be noted that the switch forming a part of the invention may include various kinds of mechanical of fluid type switching devices as well as electrical contact-type switches. I

Turning now to the illustrative embodiment of the invention, reference is made to the accompanying drawings in which:

FIG. 1 is a plan section view on an enlarged scale, the section having been taken along lines l-l of FIG. 2;

FIG. 2 is plan view of the device of FIG. 1;

FIG. 3 is a sectional view showing a modification of the invention of FIGS. 1 and 2;

FIG. 4 is an end view of one of the separable couple parts forming a part of the invention;

FIG. 5 is sectional view of a releasable fastener assembled on the garment of an operator;

FIG. 6 is a sectional view taken on line 6-6 of FIG.

FIG. 7 is a detailed view of a clip which is used in the invention; and

FIG. 8 is an overall view showing one form of the invention.

For illustrative purposes, the invention will be described in the context of an interlocking device for controlling a switch which is operable to short out the ignition system of an internal combustion engine. As indicated above, it is contemplated that this kind of switch interlock will find special utility in lightweight sport vehicles such as snowmobiles and the like and the following explanation of the invention will be made in the context of use in snowmobiles. The switch is designed so that anyone who desires to operate the vehicle must interconnect the coupling elements and when this is done, the switch is opened, eliminating the short circuit and thereby allowing the ignition system to operate normally. One of these coupling parts is connected to the operator and if the coupling parts are ever disconnected, as will occur if the operator is thrown from the vehicle, the ignition will be shorted and the vehicle will stop.

With the foregoing brief statement of the functioning of the invention, reference is now directed to FIG. I. As shown in that figure, the device includes a body member 10, which is preferably formed of a molded plastic material such as nylon 6/6. Body member 10 has a tubular end portion 11, the exterior of which is threaded as shown at 12. A radially extending flange 13 is located adjacent the threaded tubular portion.

Body member 10 is adapted to be mounted in an opening in a partition or panel such as the dashboard panel of the snowmobile or other vehicle. Although other means of fastening may be employed, in the illustrative embodiment a clamping nut 14 is threaded onto the tubular portion 11 for the purpose of clamping the body member to the panel.

In the illustrative embodiment of the invention, a pair of leads 15 are molded into the wall of the tubular part of the body member and these extend inwardly to a pair of electrical contact members l6 with which they are in electrical contact.

The hollow interior of the tubular portion is adapted to receive a contact member 17. In the form of the invention shown, the contact member 17 is adapted to move axially of the bore and in order to effect such movement, is spring urged towards the right as shown in FIG. 1 by means of a coil spring 18. Under movement of the spring and when not otherwise restrained, it bridges the contact members 16 thereby providing a circuit path from one to the other of the leads 15.

The spring and the bridging contact member 17 are held within the bore by an end plug 19. Typically, plug 19 may be radially grooved as shown at 20, the groove 20 cooperating with ribbing 21 projecting inwardly from the bore of the tubular member. The end plug is formed of a somewhat resilient material so that it can be snapped in place with the groove 20 fitting over the ribbing 21 thereby locking itself in place and holding the spring and bridging contact member in position.

The contact member 17 is actuated by actuator pin 22 which is connected to the contact member by means of a projecting nipple 23 made of a compressible material. The pin and contact member 17 are joined together by forcing the nipple through a small opening in the contact member. The nipple is formed with a radial groove at its base, the grooved section having a diameter about equal to the diameter of the opening. The nipple 'is compressed as it is passed through the opening, and then it returns to its original shape when the groove is moved into registry with the opening.

Contact member 17 is preferably simply a flat washer and fits within the groove on actuator pin 22 with a slight clearance so that it is slightly loose on the pin. As a result of the looseness, the washer is free to tilt slightly on pin 22 and make a good contact across contacts 16 despite slight misalignment of the parts.

The shank of actuator pin 22 is slideably mounted within a reduced diameter portion of the bored out interior of the housing, the reduced diameter portion being indicated by the number 220.

According to the embodiment of the invention shown in FIG. 1, the actuator 22 has an enlarged or headed portion 24. The headed portion 24 fits within a recess 25 in the end of body member 10.

The end of the body member 10 comprises one part of a pair of separable coupling parts whose function will become apparent in the following description. Preferably, the two coupling parts have a ball and socket configuration, the ball or spherically shaped part being indicated at 26 and being integral with the body member 10 in the illustrative form of the invention.

The socket part or element, indicated at 27, is formed so that the ball element 26 fits within the socket with the rim 28 of the socket fitting over the ball. The socket rim 28 is sufficiently resilient so that the socket readily snaps over the ball and can be readily separated from the ball when a predetermined pulling force is applied.

The amount of separating force required to effect separation of the ball and socket elements is a matter which is based on the resilience of the walls of the socket element 27, especially of the rim or lip 28 which surrounds the socket opening. The lip is made more yieldable by serrations as shown at 29 in FIG. 4. By this means and by careful selection of a material having the proper modulus of elasticity, a coupling which separates when just the right amount of pulling force is applied can be designed.

As a rough guideline, in the case of a snowmobile, the coupling should be sufficiently temperature stable that it will readily separate at F and yet must not accidently separate at temperatures of around F.

In the preferred embodiment, projection 30 is located interiorly of the socket element 27 in such position that it bears against the head 24 of the actuator 22. As can be seen in FIG. 1, when the coupling parts are connected together, head 24 is compressed by the projection 30 so that the contact member 17 is held in the position shown. Although the head 24 would depress even if the projection 30 was not provided within the socket, the presence of the projection compensates for thermal expansion of the parts, thus assuring that the head is depressed even though the socket element has expanded appreciably. In the illustrative form of the invention, a circuit grounding the ignition system of the engine is broken and the engine allowed to operate normally when the parts are in this position.

The socket element 27 is provided with an an eye 31 to which a cord or tether 32 is attached. The other end of the tether is adapted to be securely fastened to the vehicle operator, as will be described presently.

When the ball and socket elements are separated, the coil spring 18 will press the contact member 17 to the right as shown in FIG. 1 until the contacts 16 are bridged, thus producing a short circuit in the vehicle. When the parts are in that position, the vehicle is inoperative and if the engine is running it will immediately stop, bringing the vehicle to a halt within a short distance, especially if it is in gear.

Whenever the operator wants to start the vehicle, he must first couple the ball and socket elements together. This action causes the projection to press the actuator22 to the left as viewed in FIG. I, thus breaking the short circuit, and making the vehicle operational. He must always keep these elements coupled together in order to keep the vehicle operating.

The tether may be tied to the belt of the operator or otherwise firmly secured so that it will not separate from him with a force less than that which is required to separate the coupling elements. According to a preferred embodiment, however, the operator's jacket has secured to it a ball element shown in FIG. 5, which is secured by means of a screw 36. A flat washer 37 like element (FIGS. 5, 6 & 8) has teeth 38 which grip the fabric of the operators jacket. The underside of the ballelement 35 is also provided with teeth as indicated at 39, the arrangement preventing rotation and unloosening of the parts when fastened in place.

A socket element is tied to the other end of the tether 32. Socket element 40 is similar in configuration to the socket element 27 but differs therefrom in two important respects.

'In the first place, it is'made stronger by changing the shape as shown in FIG. 5 so that it requires a greater pulling force in order to uncouple it from its associated ball element than is required to separate

elements

26 and 27. The separating force is not so great however,

as to fail to yield in the event that the tether becomes caught on brush when the driver is speeding through the woods or on the vehicle itself if the tether becomes caught on some projecting part when he is thrown from it.

Preferably, the cord or tether is secured to the two socket elements27 and 40 in the manner shown in FIG. 8. In that view, and as shown in detail .in FIG. 7, a clip member 41, having a pair of slots 42, is secured to an end of the tether. The tether is then passed through the eyes in

socket elements

27 and 40 and the free end then passed through slots 42. So long as there is tension or at least not appreciable slack in the tether, the clip will hold it firmly in place.

However, when not under tension, the tether can be slipped through the slots 42, until its length between the two coupling sockets is adjusted to suit the operator. The advantage of this is that the right length of cord can be readily provided for all kinds and sizes of operators.

The second difference is that socket element 40 is I not provided with a projection within the socket recess. The reason for this is that the socket element 40 can be coupled to the ball element 26 when the vehicle is not in use, thus protecting the switch and actuator 22 from moisture which might otherwise cause the switch to freeze or corrode. Because of the absence of the projection, the switch remains in the closed position when element 40 is employed. It can be seen that socket element 27 will .not fit onto ball element 35 so that when the operator gets ready to start up his vehicle, he can not inadvertently connect the wrong part to his jacket.

,In operation, as in rough, snow-covered terrain, if the vehicle should hit a hidden obstruction or should anything happen which might throw the operator from his seat, the pulling force applied by the tether on the socket element 27 will cause the socket element to separate from the ball element. As soon as this occurs, the bridging contacting member 17 makes contact with the contact members 16 and the motor immediately stops. It should be noted that when the force is applied at an angle, the flange 28a acts as a reaction point and the coupling part 27 pivots about that point in effecting separation from the other coupling part. The position of the flange relative to the ball element as shown facilitates the separation of the two coupling elements especially when force is applied at a relatively large angle with respect to the axis of the elements.

Although other kinds of couplings might be used and would be capable of achieving certain objects of the invention, the ball and socket type coupling is especially well suited for the purposes for which it is herein employed. This is because such a coupling will separate when the separating force is applied through virtually any angle with respect to the axis of the coupling. Thus, no matter in what direction the operator is moving when he is thrown from or falls from the vehicle, whether it be upwardly and forwardly or to either side, the parts will separate and the vehicle engine will stop.

Another important feature of the ball and socket coupling is that it is substantially moisture-proof, when the parts are coupled together. The importance of this advantage can be recognized after it is considered that in the use of the invention in snowmobiles and other open vehicles, the coupling parts are exposed to the elements. Since the socket element covers the opening in the body part 10 the ball and socket configuration keeps moisture away from the moving parts where it might corrode them, short out the switch, or freeze and prevent operation in the intended manner.

A modification of the invention which seals the actuator pin at the switch parts is shown in FIG. 3 wherein a modified form of the body part It) is shown in section. In the modification of FIG. 3, a rubber liner or dia phram 34 is fitted within the opening 25 in the ball shaped part 25. Liner 34 is provided with a radially extending rib 35 which fits within groove 36. The end of liner 34 covers the actuator pin 22, thus providing a moisture proof seal for the pin and the switch part l6, l7 and the spring 18. The end part of the liner is sufficiently flexible so that movement of the projection 30 on the socket part 27 when the coupling parts are coupled and uncoupled, is transmitted directly to the actuator pin.

In selecting the material for the socket element, care should be taken so that the material of the socket rim and the socket sidewalls is temperature stable through the entire range of temperatures which will be met during the use of the equipment. Where the device is to be used on snowmobiles or other open vehicles used in frigid zones, temperatures down to about -50 or below may be expected and the coupling part should separate easily at such temperatures. At the other extreme, the parts should not become so flexible that they separate unintentionally at the upper end of the range of temperatures which may be encountered.

From the foregoing, it may be seen that a very simple, inexpensive and reliable safety device has been provided which is well suited for snowmobiles and other types of equipment. The device is foolproof, as long as the operator follows the simple precaution of tethering the disconnectible coupling part to his clothing. The use of this device will substantially reduce the severity of many accidents which commonly occur with small open vehicles, lawn mowers, tractors and the like.

We claim:

1. In combination with a switch, a releasable coupling comprising male and female coupling parts, one of said parts being fixed with respect to the switch and the other being separable from the first part, and resilient means on one of said parts for retaining said parts in coupled relationship and being yieldable to permit separation of the parts upon the exertion of a predetermined pulling force appliable from substantially any angular position with respect to the coupling axis, and a switch operating means controlled by said coupling parts, said means being operable to move the switch to one operating position when the coupling parts are connected and to a second operating position when the parts are separated.

2. Apparatus according to claim 1 wherein one of said coupling parts is spherically shaped and the other is provided with a socket into which the spherically shaped part fits, the socket part having a rim of resilient material surrounding the socket, said resilient rim being shaped to yieldably fit over the spherically shaped part when the parts are engaged and to permit separation of the parts upon application of the predetermined pulling force.

3. Apparatus according to claim 2 wherein the sphericallyshaped part is the part fixed with respect to the switch.

4. Apparatus according to claim 1 wherein said operating means comprises a spring for biasing said switch to said second operating position and an actuator element controlled by said separable element for moving the switch to said first operating position when the parts are connected and for releasing said switch for movement by the spring to the second operating position when the parts are separated.

5. A switch controlling device comprising a housing, a central bore in said housing, a circuit actuating element positioned in said bore, a spring urging said element axially of the bore to a first circuit controlling position, a releasable coupling comprising a ball element and a socket element, resilient means on one of said coupling elements and being engageable with the other of said coupling elements in interfitting relationship for retaining said elements in coupled relationship in the absence of a predetermined separating force and for releasing said elements on application of the predetermined separating force, one of said elements being mounted on an end of said housing and having an opening communicating with and in alignment with said bore, the other of said elements having a portion engageable with an end of said actuating element for moving the actuating element to a second circuit controlling position when the ball and socket elements are coupled together.

6. Apparatus according to claim 5 wherein the ball element is the element secured to the housing.

7. A switch controlling device comprising a releasable coupling including separable and interengageable coupling parts, one of said parts incorporating electrical switch means including a pair of electrical conductors and the other coupling part incorporating switch operating means for effecting one condition of operation of the switch means when the coupling parts are interengaged and for effecting another condition of operation of the switch means when the coupling parts are separated, one of said parts having a yieldable retaining portion engageable with the other part for holding said parts in interengaged relationship in the absence of a predetermined separating force and a flexible tether connected to one of said coupling parts and further being provided with means for attachment to an operator, said yieldable retaining portion permitting the coupling parts to be separated by a pull exerted on the tether equal to or in excess of the predetermined separating force in substantially any direction.

8. A switch controlling device according to claim 7, wherein one of said parts has a socket configuration and the other comprises a ball element adapted to fit within the socket and wherein said yieldable retaining portion comprises a resilient rim adapted to retain the ball element in the socket when the parts are interengaged and to yield to permit separation of the parts upon the application of said predetermined separating