Pull-apart safety switch with magnetic means for machines

[57] ABSTRACT

Several embodiments of pull-apart safety switches are disclosed that are for use in connection with machines from which the operator may be thrown or which he may leave with the machine remaining in motion. Each switch includes a mount to be secured to the machine and a cover so attached to the mount that it may be pulled therefrom. The mount has leads to be included in the machine circuit that is to be controlled. The cover is provided with a flexible member attachable to the operator and of sufficient length to enable him to make normal movements without pulling the cover from the mount. Each switch also has a conductor and means releasably holding it in a first relationship with the contacts when the cover is attached and a second relationship therewith when the cover is pulled free. In one of the two relationships, the control system is operative to maintain the machine in operation. Except when the control circuit is an ignition system having a magneto, said one relationship is the first relationship and in that case, said one relationship is the second relationship. In most embodiments, the cover is magnetically held in place and in second relationship circuit control, the conductor is within the mount and is held from moving into its circuit-closing position until the cover is pulled free, the conductor then being operatively positioned magnetically, resiliently, or by both such means.

Claims, 13 Drawing Figures

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PATENTEOAPR 21974 3.801,767

SHEET 1 OF 2

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PATENTEDAPR 2 1974

SHEET 2 OF 2

3,801.767

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₁ 3,801,767

PULL-APART SAFETY SWITCH WITH MAGNETIC MEANS FOR MACHINES

BACKGROUND OF THE INVENTION

The invention is adapted for use wherever it is desired to prevent the operation of a machine if its operator is not in a position in which the machine can be controlled to meet certain standards such as performance and safety. While the invention can be used in so con- ¹⁰trolling a wide range of machines, it is herein discussed with particular reference to vehicles, especially such vehicles as motorcycles, motor boats, particularly those equipped with outboard motors, and snowmobiles.

The invention is herein discussed primarily in con- ¹⁵nection with its use in vehicles such as those specifically referred to and as stopping their engines.

Even m vehicles where the throttles are self-closing, they may become stuck for various reasons and remain ,_nopen. This is particularly true in the case of snowmobiles whose throttle-operating cables often become frozen. If this happens when the operator has been thrown rom his snowmobile, the snowmobile continues in motion at a speed depending, of course, on the position in 25 which the throttle is caught. Even when the speed of the vehicle is moderate, the snowmobile may be destroyed or badly damaged. There have been occasions where injuries and even deaths were caused by runaway snowmobiles, for one example, at a race track 30 when a runaway snowmobile killed a spectator.

The problem has been recognized and one solution utilizes a switch to short out the spark when a sensor detects excessive accelerator cable tensions indicating that it has become frozen. 35

In one embodiment, the cover is held magnetically to d^_s^m°^{Unt an&lt;1 an}°^ther’ ^{k is held in place b}y ^sP^ring

Another objective of the invention is to provide that the conductor is part of the cover and is magnetically held m its first relationship and another objective is to enable the second relationship of the conductor where the safety switches are of the normally open type, to be effected by resilient means, magnetically, or by combinations thereof, the conductor being movably positioned within the mount.

Yet another objective of the invention is to provide a pull-apart switch that has first, second, and third contacts. When the first and third contacts are included in a control circuit, first relationship circuit control is provided. When the first and second leads are included in a control circuit, second relationship circuit control is provided.

A further objective of the invention is to provide pullapart switches of the last named type in which there are three conducting contacts in the mount each having an appropriate one of the leads secured thereto and with the contacts separated by magnets which are of the ceramic type and hence non-conductors. The third contact has an arm within the mount engageable with the second contact but spring-biased out of contact therewith. The cover includes a conductor interconnecting all three contacts when it is secured to the mount so that in first relationship control, the controlled circuit is opened when the cover is pulled from the mount. In second relationship circuit control, the magnetic field as applied to the switch arm is insufficiently strong to overcome the spring bias until the cover is pulled from the mount

THE PRESENT INVENTION

In accordance with the invention, the problems of preventing the continued operation of a machine when its operator is not in a predetermined location is met by ⁴⁰means of a pull-apart switch having a fixed mount, usually secured to the machine and a cover attached to the mount in a manner enabling it to be pulled therefrom. The cover has a flexible member whose free end is to be pulled if the operator moves or is moved from his position. At least in the case of vehicles, the free end is attachable to the operator and of such length that his normal movements do not result in the cover being pulled free of the mount. ₅₀

The mount is provided with two contacts connectable to the ends of the lead that controls the operation of the machine, a motor circuit or an ignition circuit. The switch also includes a conductor and means releasably holding it in a first relationship with the contacts 55 when the cover is attached to the mount and providing a second relationship with the contacts when the cover is pulled free. In one relationship, the conductor is seated against the contacts to interconnect the lead ends and in the other relationship, the conductor is ⁶⁰spaced from the contacts. In one of the two named relationships the control lead is operative to maintain the machine in operation, the first or normally closed relationship if the machine is powered by an electric motor or an engine whose ignition system includes a generator ⁶⁵and the second or normally open relationship if the ignition system of an engine includes a magneto.

SHORT DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, several embodiments of safety switches in accordance with the invention are 40 shown and

FIG. 1 is a perspective view of a snowmobile to the instrument panel of which the mount of a safety switch of the normally closed type is secured and the flexible member of its cover attached to the clothing of the op45 erator; ^H

FIG. 2 is a plan view of the safety switch with its cover attached;

FIG. 3 is a section taken approximately along the indicated lines 3—3 of FIG. 2;

⁵⁰ FIG. 4 is a section similar to FIG. 3 taken transversely of a normally open safety switch in accordance with the invention;

FIG. 5 is a like view but with the cover pulled free of ₅₅ the mount and the switch closed;

FIG. 6 is a section, similar to FIG. 4, of a normally open safety switch m accordance with another embodiment of the invention;

FIG. 7 is a like view but with the cover pulled free ₆₀ and the switch closed;

FIG. 8 is an elevational view of another normally closed switch in accordance with the invention;

FIG. 9 is a section taken approximately along the indicated lines 9—9 of FIG. 8;

₆₅ FIG. 10 is a view showing the inside surfaces of the cover and the mount;

FIG. 11 is a section, taken lengthwise of another embodiment of the invention that may function as either

3,801,767 a normally open or a normally closed switch depending on which of its leads are employed;

FIG. 12 is a like view but with the cover removed; and

FIG. 13 is a section taken approximately along the 5 indicated lines 13—13 of FIG. 11.

THE PREFERRED EMBODIMENTS OF THE INVENTION

While pull-apart switches, as previously stated, are 10 adapted for use in a wide variety of machines, they are herein discussed with particular reference to snowmobiles.

In FIG. 1, the panel of a snowmobile is indicated at 10. The snowmobile, with the embodiments of the in- 15 vention illustrated by FIGS. 1 — 5, will be assumed to have its ignition system including a generator. As such systems are well known, no details thereof are shown.

The mount 11 of a pull-apart safety switch, generally 20 indicated at 12 and shown in FIGS. 2 and 3, is secured to the panel 10 and it includes a pair of contacts 13 protruding from a molded body 14 of insulating matrial in which they are embedded with their leads 15 exposed to interconnect the ends of a lead of the ignition system 25 that will permit the operation of the snowmobile engine only when that control lead is closed. The contacts 13 are permanent magnets.

The safety switch 12 includes a molded cover 16 of insulating material shaped and dimensioned to receive ³θ within and have a short overlap with the end of the mount 11 in which the contacts 13 are exposed, the cover 16 protecting the interior from dirt, snow, etc. and covering the contacts when the snowmobile is operable. 35

The cover 16 has a conductor 17 embedded therein but exposed on its inner surface and of such length that when the cover 16 is fitted on the mount 11, the conductor 17 seats against both contacts 13 and is magnetically held thereby thus releasably but securely attach- ⁴θ ing the cover 16 to the mount 11 and establishes a normally closed switch.

The cover 16 has a tab 18, usually but not always a depending tab, to which one end of a flexible member 19 is connected with its other end attachable to the ⁴⁵clothing of the operator 20 in any desired manner, by means of a safety pin or clip (not shown ) by way of examples. The flexible member 19 is of sufficient length to permit, when attached to the operator, his normal movements without pulling the cover 16 from the ⁵⁰mount 11 but, should he be thrown from the snowmobile, the cover is pulled free thus opening the control lead of the ignition system and thereby immedately stopping the snowmobile’s engine.

The pull-apart safety switch illustrated by FIGS. 8 - ⁵⁵10 is another embodiment of a normally closed siwteh and as it is generally similar in construction and use to the switch 12, it will not be detailed and parts that correspond thereto are distinguished by the suffix addition “A” to the appropriate reference numerals. ⁶⁰

The contacts 13A are spring clips and the conductor 17A is a bar held by supports 22 embedded in the cover 16A. The contacts 13A and the conductor 17A are so positioned that when the cover 16A is in place, the conductor 17A is releasably caught by the contacts 13A establishing a normally closed switch, with the contacts covered, that opens if the cover 16A is pulled free.

The embodiments of the invention illustrated by FIGS. 4 and 5 are for use where the ignition system includes a magneto and a normally open ground lead that enables the engine to be stopped by closing that control lead.

The pull-apart safety switch of FIGS. 4 and 5 is to be incorporated in such a lead and is, accordingly, of the normally open type but as it is otherwise generally similar to the normally closed pull-apart safety switches that have been previously described, corresponding parts are not again detailed but are distinguished by the suffix addition “B” to the appropriate reference numerals.

In this embodiment of the invention, the mount 11B of the safey switch 12B has a channel 23 in its body 14B underlying the contacts 13B and dimensioned to loosely receive the conductor 17B and of such depth that when the conductor is bottomed therein, it is spaced from the contacts 13B which are permanent magnets.

The inside Of the cover 16B is provided with a post 24 of a material that is a non-conductor of electricity and shaped and dimensioned to fit between the contacts 13B to engage and bottom the conductor 17B when the cover is fitted on the mount. The cover 16B also has a pair of magnetically responsive holders 25 exposed on its inner surface, each positioned to engage the appropriate one of the permanent magnet contacts 13B thus to releasably hold the cover 16B attached to the mount 1 IB.

To ensure the engagement of the conductor 17B with the contacts 13B of the cover 16B pulled free, the channel 23 has a central pocket 26 for a spring 27 operable to force the conductor into engagement with the contacts 13B when it is not held bottomed by the post 24. .

As the embodiment of the invention illustrated by FIGS. 6 and 7 is generally similar, its parts that correspond to previously described embodiments are distinguished by the suffix addition “C” to the appropriate reference numerals. In this embodiment of the invention, a post 28 is attached to the center of the conductor 17C and the cover 16C has a central projection 24C. A resilient diaphragm 29 of the material that is a non-conductor of electricity seals the space between the permanent magnet contacts 13G but yields when engaged by the projection 24C to enable the conductor 17C to be bottomed to provide the normally open switch position when the cover 16C is in position.

In the embodiment of the invention illustrated by FIGS. 11 - 13, parts that correspond to those of previously described embodiments are distinguished by the suffix addition “D” to the appropriate reference numerals.

In this embodiment the mount 1 ID has three conductors serving as contacts 30, 31, and 32 separated from each other by a pair of magnets 33 and 34, each a nonconductor as it is of the ceramic type having magnetized particles embedded therein. Such magnets have their sides functioning as their poles. In practice the contacts and magnets are cemented together. An insulating sheet 35 is also cemented to the contact 32 and the end of a brass conductor 36 is cemented to the sheet 35. Leads 37, 38, and 39 are attached, respectively, to the contacts 30 and 32 and to the conductor 36 which includes a resilient arm 36D spaced from the inner ends of the contacts 30, 31, and 32 and provided

3,801,767 with a magnetically responsive conductor 40 dimen^S1°ned to seat against the inner ends of the contacts 30 and 31 but normally held therefrom by the resiliency of the conductor arm 36D. It will be noted that the outer and inner ends of the contacts 30, 31, and 32 extend slightly beyond the corresponding ends of the magnets 33 and 34. In practice the inner ends of the assembled contacts, magnets, the sheet 35 and the conductor 36 are fitted into a shell 41 housing and providing space for the movement of the switch arm 36D and its con- 10 ductor 40 and the assembly is molded into the material from which the mount 11D is formed with the leads outside the shell.

The cover 16D has its conductor 17D dimensioned not only to be m engagement with the outer ends of all 15 three of the contacts 30, 31, and 32 but also to provide ^{maSS that iS subst}^tially larger than that of the conductor 40.

When the leads 37 and 38 are connected to be included m the control circuit, first relationship control 20 ^1S-7°n^du^{d SlnC}® ^{the conductor} 17D is in engagement with all three of the contacts 30, 31, and 32. When the leads 37 and 39 are connected to be included in a control circuit, second relationship control is provided Because of the substantial difference between the mass of 25 the conductor 17D and that of the conductor 40, the conductor 40 is not magnetically pulled into engagement with the contacts 30 and 32 while the cover 16D is attached to the mount 11D.

While the mounts of the safety switches may be oth- ³⁰erwise attached, they are shown as having wings apertured to permit them to be secured to the panel 10 by screws and preferably they also may have on their back surfaces a length of a tape (not shown) having both surfaces adhesive coated and with the exposed adhesive ³⁵coated face protected by a removable paper sheet