EMERGENCY STOP SWITCH MEANS FOR A SNOWMOBILE OR THE LIKE
United States Patent 3758736
In an emergency stop switch means for a snowmobile on the like a throttle lever is rotatably mounted on a handle through a bracket thereby controlling an operating lever of carburetor. These levers are connected with each other by an inner wire in an outer sheath the end of which is held in fixed relation while the other is adapted to permit a moving element to slidably move until a contacting element thereof abuts against a counter-element. In an emergency, the throttle lever is released so that a spring compressed between the bracket and the moving element recovers its pressure force and contacts said contacting elements with each other whereby an electric ignition circuit is earthed to stop rotation of a snowmobile engine.
US Patent References:
SAFETY DEVICE FOR AN INTERNAL COMBUSTION ENGINE
Albertson - June 1972 - 3672344
COMBINED AUXILIARY THROTTLE AND SAFETY SWITCH FOR SNOWMOBILE
Preble - June 1971 - 3583506
FAIL-SAFE THROTTLE CONTROL
MacMillian - December 1971 - 3626919
ELECTRIC CONTACT UNITS OF CABLE CONTROL DEVICES
Lombard - March 1969 - 3435165
SAFETY DEVICE FOR AN INTERNAL COMBUSTION ENGINE
Albertson - June 1972 - 3672344
COMBINED AUXILIARY THROTTLE AND SAFETY SWITCH FOR SNOWMOBILE
Preble - June 1971 - 3583506
FAIL-SAFE THROTTLE CONTROL
MacMillian - December 1971 - 3626919
ELECTRIC CONTACT UNITS OF CABLE CONTROL DEVICES
Lombard - March 1969 - 3435165
Application Number:
05/236808
Publication Date:
09/11/1973
Filing Date:
03/22/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
74/502.200, 180/271, 74/489, 123/198DC, 200/61.850
International Classes:
H01H3/02; H01H17/20
Field of Search:
200/157,161,61.85,61.86,61.87 180/5R,82R,103,77R 123/198D,198DB,198DC,98
Primary Examiner:
Schaefer, Robert K.
Assistant Examiner:
Vanderhye, Robert A.
Claims:
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows
1. An emergency stop switch means adapted to be used for an oversnow vehicle such as a snowmobile or the like having a bracket means rigidly fixed to a handle portion of said vehicle, a throttle lever pivotally supported to said bracket means, a wire for connecting said throttle lever to an operating lever for opening and closing a carburetor valve of an engine, and an electrical ignition circuit by which said engine is electrically ignited through an ignition coil, said emergency stop switch means comprising;
2. An emergency stop switch means as set forth in claim 1, in which said fixed contacting element is rigidly fixed to said handle portion and mounted to said bracket means for pivotally supporting said throttle lever.
3. An emergency stop switch means as set forth in claim 1, in which the terminal of said outer sheath at the side of said engine is rigidly fixed to said carburetor.
4. An emergency stop switch means as set forth in claim 1, in which said bracket means is provided with a notched portion wherein said movable mechanism is movably mounted, said fixed contacting element being mounted to the opening end of said notched portion.
1. An emergency stop switch means adapted to be used for an oversnow vehicle such as a snowmobile or the like having a bracket means rigidly fixed to a handle portion of said vehicle, a throttle lever pivotally supported to said bracket means, a wire for connecting said throttle lever to an operating lever for opening and closing a carburetor valve of an engine, and an electrical ignition circuit by which said engine is electrically ignited through an ignition coil, said emergency stop switch means comprising;
2. An emergency stop switch means as set forth in claim 1, in which said fixed contacting element is rigidly fixed to said handle portion and mounted to said bracket means for pivotally supporting said throttle lever.
3. An emergency stop switch means as set forth in claim 1, in which the terminal of said outer sheath at the side of said engine is rigidly fixed to said carburetor.
4. An emergency stop switch means as set forth in claim 1, in which said bracket means is provided with a notched portion wherein said movable mechanism is movably mounted, said fixed contacting element being mounted to the opening end of said notched portion.
Description:
The present invention relates to an emergency stop switch means particularly suitable to be used in an oversnow vehicle such as a snowmobile, a motorized sled or the like which runs on the snowfield.
Generally it is desirable to provide oversnow vehicles with a special mechanism through which they can stop promptly in an emergency so as to obviate accidents that might otherwise occur.
For this express purpose, it has been customary to provide an emergency stop switch means whereby the electrical ignition circuit of the oversnow vehicle is designed to be earthed so as to bring the rotation of the vehicle engine to a stop.
The conventional type of such an emergency stop switch means is mounted on an instrument board so that in order to manually operate the same, it is necessary to actuate the switch means with one hand while grasping the handle with the other hand. Thus the result is that an operator is forced to assume an unnatural seated posture wherein the operation of such a switch means is not reliable; and this is especially the case in an emergency when an operator is often pressed and is liable to be confused and to manipulate the switch means with uncertainty so that he often fails to halt the rotation of the engine before the snowmobile or the like overturns or is involved in an accident.
Also there is a further difficulty to overcome in that snowmobiles or the like are provided with a hand operated throttle lever and in severely cold weather it is not uncommon for the inner wire of the throttle control cable to become frozen to the outer wire thereof whereby actuation of the throttle fails to close the carburetor and on many occasions the operator is not aware of the fact. In addition, other difficulties can arise if the aforementioned inner wire has been disconnected for some reasons unknown to the operator and becomes frozen up in this disconnected relation before he is aware of the fact so that even if he releases his grasp of the throttle lever, he cannot move the inner wire so as to close the carburetor, consequently causing the snowmobile or the like to continue to run at full speed with increased risk of a collision.
For the purpose of eliminating the above-mentioned and other difficulties, the present invention contemplates the provision in a snowmobile, motorized sled or the like of such a means that enables an operator to easily switch on and stop the rotation of an engine. To be more precise, the present invention contemplates the provision of an emergency stop switch means which can automatically act to halt the rotation of the vehicle engine even in the event that the carburetor is not closed upon release of its associated throttle lever in an emergency and where, for example, the cable connected with the throttle lever for operation of the carburetor becomes frozen.
In other words, the mechanical arrangements of the present invention are such that a throttle lever is mounted on a handle portion of the vehicle and serves to control the rotary speed of the engine and has an emergency stop switch means mounted thereon in a manner enabling an operator to operate the vehicle with the highest degree of safety, the emergency stop switch means being ready to automatically work in an emergency to stop the engine.
The emergency stop switch means in accordance with the present invention is adapted to automatically operate and to stop the rotation of the engine merely by the operator releasing his grasp of the throttle lever which is mounted on a handle portion of the vehicle, that is, merely by removing the load acting on the throttle lever.
Accordingly, it is one of the principal objects of the present invention to provide an emergency stop switch means having a very simple and durable structure that can be manufactured economically on a large scale and which in use is employed to obviate operational accidents that otherwise may occur during the operation of an oversnow vehicle such as a snowmobile or the like especially in severe weather conditions.
It is another object of the invention to provide such a mechanical structure for an emergency stop switch means that enables it to be mounted on a handle portion or other suitable position of the vehicle where an operator is able to manipulate the same in a carefree manner thereby to prevent the operational jeopardies of a snowmobile car or the like.
It is further another object of the invention to provide an emergency stop switch means the mechanical structure of which is mounted on the vehicle handle in movable relation with the throttle lever.
It is a still further object of the invention to provide an emergency stop switch means for a snowmobile or the like in which when the inner wire of the throttle control cable or the lever for operating the carburetor has become frozen or otherwise inoperative before the operator is aware of it, the engine ignition circuit is automatically earthed merely by the operator releasing his grasp of the throttle control lever so as to stop the ignition of the spark slug and bring the rotation of the vehicle engine to a halt.
With this and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:
FIG. 1 is a perspective view showing a snowmobile having mounted on the handle thereof an emergency stop switch means in accordance with the present invention;
FIG. 2 is a vertical cross-sectioned view showing a detail of the throttle lever forming part of the emergency stop switch means;
FIG. 3 is a schematic view illustrating the manner in which the throttle lever is grasped by hand whereby the inner wire is stretched;
FIG. 4 is a schematic view illustrating the manner in which the throttle lever is released in an emergency when the snowmobile is running; and
FIG. 5 is a schematic diagram of an electrical circuit for actuating the emergency stop switch means.
Setting forth in detail some preferred embodiments of the invention with reference to the accompanying drawings, reference character a designates a handle means of the oversnow vehicle or snowmobile. The handle means a has at one side thereof a throttle lever movably pivoted through a bracket z secured to the handle means a and at the other side a brake lever c movably pivoted through a bracket z' secured to the handle means a, respectively.
The throttle lever b, as is generally shown as an example by reference numeral 1 in FIG. 2, is formed as a reversely bent U-shaped metallic plate, the leg portions of which are provided with perforated hole 2 formed in aligned relation with each other thereby to allow both the throttle lever and the brake lever to be movably pivoted to the bracket z as mentioned herein above. Said throttle lever body 1 is provided with perforated hole 3 through which an inner wire to be subsequently described is extended.
Said bracket z is bored through a wall 12 forming part thereof with a hole 4 in opposed relation to the hole 3 perforated in the throttle lever body 1. Said hole 4 includes a continued hollow portion 5. A short shaft 6 is inserted in said perforated hole 2 and pivotally supports the throttle lever body 1 so as to permit the same to move about the short shaft 6.
To a portion of the opening edge of the hollow portion 5 there is fixed a metallic contacting element 7 facing opposedly to the wall 12 in which the hole 4 is bored, said metallic contacting element being connected to a lead wire 8.
In the inside of said hollow portion 5 there is also provided a metallic contacting element 9 facing opposedly to said element 7 while a cylindrical moving element 11 is slidably mounted which has a base perforated with a hole 10 facing opposedly to said hole 4.
Between said moving element 11 and said wall 12 there is oppressively held a helicoidal spring 13 thereby normally pressing the moving element 11 toward said opening of the hollow portion 5. Said metallic contacting element 9 is connected to a lead wire 14.
Meanwhile, a helicoidal spring 17 is extended between an operational lever 15 for controlling the carburetor valve (not shown) and a fixture element 16 rigidly fixed adjacent thereto. To said fixture element 16 is fixed a cylindrical receiving element 19 having a base bored with a hole 18.
Nextly, a ball or swollen body 21 formed at one terminal of an inner wire 20 is held on the peripheral edge of the hole 3 provided on the throttle lever body 1 with the other end of said wire 20 passing through the holes 4, 10 and a perforated hole 18 similar thereto.
Further, one end of an outer sheath 22 is inserted in the cylindrical portion of said moving element 11 while the other end in the cylindrical portion of said receiving element 19. Then the inner wire 20 is pulled to a full extent so as to give the maximum degree of its pressure force to the helicoidal spring 13 held between the moving element 11 and the wall 12 thereby fixing the inner wire 20 to the operational lever 15 at a point 23 where said pressure force is applied. In this state, the helicoidal spring 13 is fully compressed so that a small space is produced between the metallic contacting elements 7 and 9. The other end of the lead wire 8 is connected to the contact point Q of the ignition coil P in the electrical ignition circuit of the engine as is shown by reference character X in the wiring diagram 5 and the other end of the lead wire 14 is earthed through the metallic contacting element 9. Thus when said element 9 abuts against the element 7, the current flow through the circuit will be earthed so that the spark plug R does not fire and the rotation of an engine is brought to a halt.
The emergency stop switch means in accordance with the present invention is so constructed as has been herein described above, and the mechanical functions and operational merits thereof will now be referred to.
The throttle lever b, together with the handle a in one hand, is moved about the short shaft 6 so as to pull the inner wire 20 thereby drawing the carburetor operating lever 15 closer to the fixture element 16 against the pressure force of the helicoidal spring 17. By so doing, said carburetor valve is opened free to start the engine as in the normal case.
The embodiment showing the above-mentioned operational condition is definitely illustrated in FIG. 3. In this case, the greater force the inner wire 20 is given in the direction of the arrow shown in the solid line, the greater counter force is given to the outer sheath 22 in the direction of the arrow shown in the dotted line so that the sheath 22 is inclined to be extended in said direction. However, it cannot be extended in the least toward the fixture element 16 because one end of the sheath is inserted in the receiving element 19 rigidly fixed to the fixture element 16. Thus the result is that the outer sheath 22 is extended in the opposite direction, that is to say, toward the moving element 11 thereby compressing the helicoidal spring 13 therethrough. From this it will be readily understood that the faster the engine is rotated by further moving the throttle lever b, the greater becomes the pressure force exerted by the spring 13 as it is further compressed.
If the snowmobile or the like continues running like this at high speeds while an operator is not aware of this spring condition, the inner wire 20 and/or the carburetor may be frozen together with the outer sheath 22 thereof under the influence of the cold weather.
Thus when he happens in such a case to notice obstacles in front of him, he cannot slow up the rotary speed of the engine so as to drive the snowmobile quite clear of such obstacles even if he releases his grasp of the throttle lever b with the intention of closing the carburetor because the operational lever 15 of the carburetor connected to the throttle lever b by means of the inner wire 20 is also made inoperative. Thus the result is that the throttle lever cannot work at all and the engine still continues to rotate at the same high speed.
However, the throttle lever b being substantially released, the pressure force exerted by the spring 13 against the outer sheath 22 is released. Consequently, the spring 13, that had been compressed before the throttle lever b was released, recovers its pressure force and presses the moving element 11 toward the metallic contacting element 7 thereby bringing the metallic contacting element 9 into contact with said element 7. In other words, the electrical circuit shown in FIG. 5 is earthed so that the spark plug R is not ignited and thus the engine is stopped thereby bringing the snowmobile to a halt.
Thus the present invention is concerned with the provision of such an electric switch means for emergency stop only as can be operated merely by releasing the hand-grasping power of the throttle lever b when an operator comes across obstacles in front of him while running the snowmobile with the throttle lever b in hand.
Further the emergency stop switch means in accordance with the present invention is substantially so adapted as to work by operating the throttle lever b mounted on a handle means as has been mentioned, so that an operator can easily operate the same thereby to stop the rotation of an engine and bring the snowmobile to a halt at his comfortable seated posture which it is necessary to take the trouble of changing when he intends to operate the conventional type of emergency stop switch means.
Thus it is very clear that the emergency stop switch means of the present invention provides many advantages that, in addition to being very easily operable, it is excessively simple in structure and producible economically on a large scale thereby making it possible to secure many operational effects and mechanical merits that cannot be obtained by the conventional type of emergency stop switch means.
Generally it is desirable to provide oversnow vehicles with a special mechanism through which they can stop promptly in an emergency so as to obviate accidents that might otherwise occur.
For this express purpose, it has been customary to provide an emergency stop switch means whereby the electrical ignition circuit of the oversnow vehicle is designed to be earthed so as to bring the rotation of the vehicle engine to a stop.
The conventional type of such an emergency stop switch means is mounted on an instrument board so that in order to manually operate the same, it is necessary to actuate the switch means with one hand while grasping the handle with the other hand. Thus the result is that an operator is forced to assume an unnatural seated posture wherein the operation of such a switch means is not reliable; and this is especially the case in an emergency when an operator is often pressed and is liable to be confused and to manipulate the switch means with uncertainty so that he often fails to halt the rotation of the engine before the snowmobile or the like overturns or is involved in an accident.
Also there is a further difficulty to overcome in that snowmobiles or the like are provided with a hand operated throttle lever and in severely cold weather it is not uncommon for the inner wire of the throttle control cable to become frozen to the outer wire thereof whereby actuation of the throttle fails to close the carburetor and on many occasions the operator is not aware of the fact. In addition, other difficulties can arise if the aforementioned inner wire has been disconnected for some reasons unknown to the operator and becomes frozen up in this disconnected relation before he is aware of the fact so that even if he releases his grasp of the throttle lever, he cannot move the inner wire so as to close the carburetor, consequently causing the snowmobile or the like to continue to run at full speed with increased risk of a collision.
For the purpose of eliminating the above-mentioned and other difficulties, the present invention contemplates the provision in a snowmobile, motorized sled or the like of such a means that enables an operator to easily switch on and stop the rotation of an engine. To be more precise, the present invention contemplates the provision of an emergency stop switch means which can automatically act to halt the rotation of the vehicle engine even in the event that the carburetor is not closed upon release of its associated throttle lever in an emergency and where, for example, the cable connected with the throttle lever for operation of the carburetor becomes frozen.
In other words, the mechanical arrangements of the present invention are such that a throttle lever is mounted on a handle portion of the vehicle and serves to control the rotary speed of the engine and has an emergency stop switch means mounted thereon in a manner enabling an operator to operate the vehicle with the highest degree of safety, the emergency stop switch means being ready to automatically work in an emergency to stop the engine.
The emergency stop switch means in accordance with the present invention is adapted to automatically operate and to stop the rotation of the engine merely by the operator releasing his grasp of the throttle lever which is mounted on a handle portion of the vehicle, that is, merely by removing the load acting on the throttle lever.
Accordingly, it is one of the principal objects of the present invention to provide an emergency stop switch means having a very simple and durable structure that can be manufactured economically on a large scale and which in use is employed to obviate operational accidents that otherwise may occur during the operation of an oversnow vehicle such as a snowmobile or the like especially in severe weather conditions.
It is another object of the invention to provide such a mechanical structure for an emergency stop switch means that enables it to be mounted on a handle portion or other suitable position of the vehicle where an operator is able to manipulate the same in a carefree manner thereby to prevent the operational jeopardies of a snowmobile car or the like.
It is further another object of the invention to provide an emergency stop switch means the mechanical structure of which is mounted on the vehicle handle in movable relation with the throttle lever.
It is a still further object of the invention to provide an emergency stop switch means for a snowmobile or the like in which when the inner wire of the throttle control cable or the lever for operating the carburetor has become frozen or otherwise inoperative before the operator is aware of it, the engine ignition circuit is automatically earthed merely by the operator releasing his grasp of the throttle control lever so as to stop the ignition of the spark slug and bring the rotation of the vehicle engine to a halt.
With this and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:
FIG. 1 is a perspective view showing a snowmobile having mounted on the handle thereof an emergency stop switch means in accordance with the present invention;
FIG. 2 is a vertical cross-sectioned view showing a detail of the throttle lever forming part of the emergency stop switch means;
FIG. 3 is a schematic view illustrating the manner in which the throttle lever is grasped by hand whereby the inner wire is stretched;
FIG. 4 is a schematic view illustrating the manner in which the throttle lever is released in an emergency when the snowmobile is running; and
FIG. 5 is a schematic diagram of an electrical circuit for actuating the emergency stop switch means.
Setting forth in detail some preferred embodiments of the invention with reference to the accompanying drawings, reference character a designates a handle means of the oversnow vehicle or snowmobile. The handle means a has at one side thereof a throttle lever movably pivoted through a bracket z secured to the handle means a and at the other side a brake lever c movably pivoted through a bracket z' secured to the handle means a, respectively.
The throttle lever b, as is generally shown as an example by reference numeral 1 in FIG. 2, is formed as a reversely bent U-shaped metallic plate, the leg portions of which are provided with perforated hole 2 formed in aligned relation with each other thereby to allow both the throttle lever and the brake lever to be movably pivoted to the bracket z as mentioned herein above. Said throttle lever body 1 is provided with perforated hole 3 through which an inner wire to be subsequently described is extended.
Said bracket z is bored through a wall 12 forming part thereof with a hole 4 in opposed relation to the hole 3 perforated in the throttle lever body 1. Said hole 4 includes a continued hollow portion 5. A short shaft 6 is inserted in said perforated hole 2 and pivotally supports the throttle lever body 1 so as to permit the same to move about the short shaft 6.
To a portion of the opening edge of the hollow portion 5 there is fixed a metallic contacting element 7 facing opposedly to the wall 12 in which the hole 4 is bored, said metallic contacting element being connected to a lead wire 8.
In the inside of said hollow portion 5 there is also provided a metallic contacting element 9 facing opposedly to said element 7 while a cylindrical moving element 11 is slidably mounted which has a base perforated with a hole 10 facing opposedly to said hole 4.
Between said moving element 11 and said wall 12 there is oppressively held a helicoidal spring 13 thereby normally pressing the moving element 11 toward said opening of the hollow portion 5. Said metallic contacting element 9 is connected to a lead wire 14.
Meanwhile, a helicoidal spring 17 is extended between an operational lever 15 for controlling the carburetor valve (not shown) and a fixture element 16 rigidly fixed adjacent thereto. To said fixture element 16 is fixed a cylindrical receiving element 19 having a base bored with a hole 18.
Nextly, a ball or swollen body 21 formed at one terminal of an inner wire 20 is held on the peripheral edge of the hole 3 provided on the throttle lever body 1 with the other end of said wire 20 passing through the holes 4, 10 and a perforated hole 18 similar thereto.
Further, one end of an outer sheath 22 is inserted in the cylindrical portion of said moving element 11 while the other end in the cylindrical portion of said receiving element 19. Then the inner wire 20 is pulled to a full extent so as to give the maximum degree of its pressure force to the helicoidal spring 13 held between the moving element 11 and the wall 12 thereby fixing the inner wire 20 to the operational lever 15 at a point 23 where said pressure force is applied. In this state, the helicoidal spring 13 is fully compressed so that a small space is produced between the metallic contacting elements 7 and 9. The other end of the lead wire 8 is connected to the contact point Q of the ignition coil P in the electrical ignition circuit of the engine as is shown by reference character X in the wiring diagram 5 and the other end of the lead wire 14 is earthed through the metallic contacting element 9. Thus when said element 9 abuts against the element 7, the current flow through the circuit will be earthed so that the spark plug R does not fire and the rotation of an engine is brought to a halt.
The emergency stop switch means in accordance with the present invention is so constructed as has been herein described above, and the mechanical functions and operational merits thereof will now be referred to.
The throttle lever b, together with the handle a in one hand, is moved about the short shaft 6 so as to pull the inner wire 20 thereby drawing the carburetor operating lever 15 closer to the fixture element 16 against the pressure force of the helicoidal spring 17. By so doing, said carburetor valve is opened free to start the engine as in the normal case.
The embodiment showing the above-mentioned operational condition is definitely illustrated in FIG. 3. In this case, the greater force the inner wire 20 is given in the direction of the arrow shown in the solid line, the greater counter force is given to the outer sheath 22 in the direction of the arrow shown in the dotted line so that the sheath 22 is inclined to be extended in said direction. However, it cannot be extended in the least toward the fixture element 16 because one end of the sheath is inserted in the receiving element 19 rigidly fixed to the fixture element 16. Thus the result is that the outer sheath 22 is extended in the opposite direction, that is to say, toward the moving element 11 thereby compressing the helicoidal spring 13 therethrough. From this it will be readily understood that the faster the engine is rotated by further moving the throttle lever b, the greater becomes the pressure force exerted by the spring 13 as it is further compressed.
If the snowmobile or the like continues running like this at high speeds while an operator is not aware of this spring condition, the inner wire 20 and/or the carburetor may be frozen together with the outer sheath 22 thereof under the influence of the cold weather.
Thus when he happens in such a case to notice obstacles in front of him, he cannot slow up the rotary speed of the engine so as to drive the snowmobile quite clear of such obstacles even if he releases his grasp of the throttle lever b with the intention of closing the carburetor because the operational lever 15 of the carburetor connected to the throttle lever b by means of the inner wire 20 is also made inoperative. Thus the result is that the throttle lever cannot work at all and the engine still continues to rotate at the same high speed.
However, the throttle lever b being substantially released, the pressure force exerted by the spring 13 against the outer sheath 22 is released. Consequently, the spring 13, that had been compressed before the throttle lever b was released, recovers its pressure force and presses the moving element 11 toward the metallic contacting element 7 thereby bringing the metallic contacting element 9 into contact with said element 7. In other words, the electrical circuit shown in FIG. 5 is earthed so that the spark plug R is not ignited and thus the engine is stopped thereby bringing the snowmobile to a halt.
Thus the present invention is concerned with the provision of such an electric switch means for emergency stop only as can be operated merely by releasing the hand-grasping power of the throttle lever b when an operator comes across obstacles in front of him while running the snowmobile with the throttle lever b in hand.
Further the emergency stop switch means in accordance with the present invention is substantially so adapted as to work by operating the throttle lever b mounted on a handle means as has been mentioned, so that an operator can easily operate the same thereby to stop the rotation of an engine and bring the snowmobile to a halt at his comfortable seated posture which it is necessary to take the trouble of changing when he intends to operate the conventional type of emergency stop switch means.
Thus it is very clear that the emergency stop switch means of the present invention provides many advantages that, in addition to being very easily operable, it is excessively simple in structure and producible economically on a large scale thereby making it possible to secure many operational effects and mechanical merits that cannot be obtained by the conventional type of emergency stop switch means.