Patent Publication Number: US-3875821-A

Title: Resetting device

Description:
United States Patent 11 1 Neumann i 1 RESETTING DEVICE Joachim Neumann, Stuckheim. Germany [75] Inventor:  
 [22] Filed: Dec. 4, 1973 [2]] Appl. No.: 421.629  
 [58] Field of Search. 74/513. 577 R. 577 S. 577 SF, 74/578. 2. 526; 123/198 DB [56] References Cited UNITED STATES PATENTS 3.580.370 5/1971 McCammon 74/513 X 3.698.372 10/1972 Eshelman et al 1 123/198 DB [451 Apr. 8, 1975 3.760.786 9/1973 Marsh 1. 74/513 X Primary E.tmniner-Samuel Scott Assistant E.\&#39;aminer-Frank Hv McKenzie. Jr. Attorney. Agent. or Firm-Ernest F. Marmorck [57] ABSTRACT For use with the throttle valve shaft of a carburetor or the like. the present invention provides a resetting device that normally opposes the displacement of the actuating element for the throttle valve shaft. The present invention is particularly characterized by a second. prestressed spring for resetting the actuating element should the first spring become inoperative. Means are provided for normally restraining the second spring so that it does not function unless the first spring becomes inopcrative. The second spring is automatically released by the restraining means and is arranged to apply a force of equal magnitude to the normal force of the first spring after the first spring is inoperative.  
 14 Claims. 2 Drawing Figures 1 RESETTING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a resetting device and more particularly to a resetting device having spring means for counteracting the displacement or shifting of an actuation element.  
 2. Description of the Prior Art Reset devices of the type to which the present invention is directed operate with spring tension of a reset spring and are well known in the art. The prior art reset devices are used for returning an actuating element to its starting position when the force or regulating power that effects the displacement of the actuating element is not available. If it is required that the actuating element be reset also when the biasing spring is inoperative. for example, when the spring is destructed, it could be proposed to use a second similarly functioning spring which is parallel to the first reset spring of the prior art. However, such an arrangement would have the disadvantage that, during normal operation. the intervention or application of their respective forces by both springs would exert a total force that is excessive since the force of the second spring would be added to the force of the first spring. Thus a larger regulating power would be required to displace the actuating elements. However, if in order to overcome this disadvantage, two lighter springs are used in parallel such that their total force equals that of a single heavier spring, then the result would be a slower and less reliable setting of the actuating element when one of the two lighter springs is inoperative and this too is undesirable.  
 SUMMARY OF THE INVENTION The underlying task of the present invention resides in creating a reset device of the initially mentioned type, that is without a pair of springs acting in parallel with each other, which operates with spring tension and which, without increasing the regulation force required for the displacement of the actuating element, makes possible a reliable and fast return of the actuating element during normal operation as well as when the customarily provided first spring is inoperative.  
  In accordance with the present invention, the foregoing task is carried out by the provision ofa second, prestressed spring that is used for resetting the actuating element. The second prestressed spring is normally blocked when the first spring is operative. The second spring is released only when the first spring is inoperative. As a result of the fact that, in accordance with the present invention, the second spring cannot exert its influence on the actuating element during the time period of normal operation ofthe first spring, the second spring force cannot be added to the first spring force. Therefore, a higher or double regulating force is not required for the displacement of the actuating element. On the other hand. due to the fact that the blockage of the second spring is automatically cancelled when the first spring becomes inoperative, the engagement of the second spring with the actuating element is assured with the same force as the first spring so that a reliable restoration of the actuating element to its starting position is always guaranteed.  
  In accordance with one embodiment of the present invention a first tension spring is secure between a springy, flexible pawl member and the actuating element and thereby prevents the engagement of a second spring with the actuating element. In this first embodi ment, the pawl member is constructed in the form of a leaf-type spring which is provided with a stop member whereby the stop member of the leaf-type spring prevents the engagement of the second spring with the actuating member when the leaf-type spring is in a loaded or deflected position. The springy pawl member, in a very simple manner, makes it possible to block the second spring for as long a time period as the first tension spring is engaged in the prescribed manner. When the first tension spring becomes inoperative for any reason. the pawl member takes on a relaxed position. When this occurs, the stop member releases the second spring so that the second spring can apply a force to the actuating element in place of and with substantially the same force as the first tension spring. As a further feature of the present invention, a displacing or entrainer device is provided by means of which the second spring, after it is released by the movement of the stop member of the pawl, applied a force to the actuating member.  
  In accordance with a preferred embodiment of the present invention, the second spring is constructed as a tension spring and is secured to a pivotable, elongated drag lever. One extremity of the drag lever engages the pawl member and, more particularly, engages the stop member. The other extremity of the drag lever includes the displacing or entrainer device which may be in the form of a hook that is arranged to engage the actuating member.  
  In still another embodiment of the present invention a spring defined by an elongated leg having a free end is provided to serve the function of the second spring whereby, in the loaded state of the pawl member, the free end of the spring is locked in position by the stop of the pawl member. When the free end of the spring is released after the first spring becomes inoperative and the pawl member takes its relaxed position. the free end of the spring bears against a displacing or entrainer device that is integral with the actuating member.  
  Both embodiments of the present invention are particularly characterized by a simple construction that assures proper functioning. In each embodiment, the two springs that actually urge the actuating element have approximately the same spring rate.  
  Accordingly it is an object of the present invention to provide an improved resetting device.  
  Still another object of the present invention is to provide an improved resetting device, as described above, wherein two springs are used, one in place of the other, when the first normally operating spring becomes inoperative.  
  A further object of the present invention is to provide an improved resetting device, as described above, wherein the two springs have approximately the same spring rate.  
  A further object of the present invention, as described above, is to provide means for automatically rendering the second spring operative when the first spring becomes inoperative.  
  These and other objects, features and advantages of the invention, will, in part, be pointed out with particularlity, and will, in part, become obvious from the following more detailed description of the invention,  
 taken in conjunction with the accompanying drawing, which forms an integral part thereof.  
 BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. I ofthe drawing the actuating mechanism for the throttle valve of a carburetor used in an internal combustion engine, for example a motor vehicle, is shown and the reference character 1 represents an elongated lever which defines an actuating element. In a well known manner, the actuating element is coupled to the throttle valve shaft 2 of the carburetor for rotation together therewith. The actuating lever is manipulated, via a rod-system or a cable line 3, by means of an accelerator foot pedal which is not illustrated in the attached drawings The movement of the actuating lever l is in a direction that is in opposition to the force exerted by a first tension spring 4. One extremity of the first tension spring is secured to the actuating lever 1 intermediate the ends thereof. The other extremity of the first tension spring 4 is secured to the free end of an elongated leaf type spring 6 which is tightly clamped at its other end and which is also provided with an integral stop member 5. In the starting position ofthe actuating lever, such as shown by solid lines in FIG. I the first tension spring 4 retains the leaf-type spring 6 in a tightened or loaded position in which a portion of the leaf-type spring 6 that is intermediate the stop 5 and the first tension spring 4 bears against a second stop 7.  
  In the loaded position of the leaf-type spring 6 the stop 5 engages a first, free extremity of an elongated drag lever 8 which can be freely pivoted about the throttle valve shaft 2. The drag lever 8 is urged in a clockwise direction by a second spring 9 which, in the first embodiment, is constructed in the form of a tension spring.  
  When the first tension spring 4 becomes inoperative for any reason, the leaf-type spring 6 relaxes and assumes the dashed line position designated by the reference character 6&#39; in FIG. 1. Thus, in the relaxed position of the spring 6, the stop 5 no longer engages the first. free extremity of the drag lever 8 so that the second tension spring 9 can then pivot the drag lever 8 in clockwise direction about the axis of the throttle valve shaft 2. This rotational movement of the drag lever 8 causes the opposite end or second free extremity of the drag lever 8 to engage the actuating lever l intermediate the axis ofthe throttle valve shaft 2 and the connection point of the cable line 3. An entrainer-hook 10, which is integral with the second free extremity of the drag lever 8 bears against the actuating lever 1 as shown by the reference character 8&#39;. This is indicated by dashed lines in FIG. I. The entrainer hook 10 engages the actuating lever I with a force that is opposite to the force of the displacement action that is initiated by the cable line 3 but which is in the same direction as the force that was initially applied by the first tension spring 4 which, at this time, is inoperative.  
  In FIG. 2, a resetting device designed in accordance with an alternative embodiment of the present invention is shown and is designed somewhat differently from the resetting device shown in FIG. 1. However, in FIG. 2, the reference characters 1-7 correspond to those same reference characters in FIG. 1. In place of the drag lever 8, which is acted upon by the tension spring 9 in the first embodiment, a spring 11 is provided in the embodiment of FIG. 2 which, at one of its extremities 12, is rigidly anchored and at its other or free extremity bears against the stop 5 of the leaf-type spring 6. When the first tension spring 4 becomes inoperative the leaf-type spring 6 takes on the relaxed position 6&#39; shown in dashed lines in FIG. 2 and thus releases a leg 13 of the spring 11 whereby the leg I3 then moves in a clockwise direction and is caught by an entrainer hook 14 that projects from the end of the actuating lever that is opposition to the connection point of the cable line 3. In this position, which is indicated by the dashed line 13&#39;, the spring 11 urges the actuating lever I in an opposite direction to the displacement resulting from the action of the cable line 3.  
  As long as the first tension spring 4 is in a state ofengagement, the actuating lever l is loaded only by the first tension spring 4. The first tension spring 4 acts in opposition to the displacement of the actuating lever 1 that results from the action of the cable line 3. After the displacement force is no longer exerted by the cable line 3, the first spring 4 returns the actuating lever to the starting position shown in solid outline in FIG. 1 and in FIG. 2. This corresponds to the idling state of the carburetor. However, if the first spring 4 becomes inoperative, such as possibly through a destruction or through an unhinging or disconnection of one of its extremities, then either of the second springs 9 or II, which previously had been blocked through the intervention of the stop 5 on the springy pawl member 6, takes over the function of the first tension spring 4 because the blocking action is automatically cancelled by the springy pawl member 6 returning to its nonblocking or rest position 6 shown in dashed outline in FIG. 1 and in FIG. 2. Since both springs, that is the first spring 4 and the second spring 9 or 11 have spring tensions ofsimilar orders of magnitude, the resetting of the actuating lever is taken care of equally well by both springs 4 and 9 or 11 and this is done in such a manner that the second spring 9 or 11 is only displaced at such time when the first spring 4 is inoperative. Due to the blockage of the second spring 9 or 11, an addition of the spring tensions, that is, an increase of the displacement force necessary for the displacement of the actuating lever I does not occur.  
  However, should the situation arise where the stop member 5 of the leaf-type spring 6 disengages itself accidentally from the drag lever 8 or from the free leg 13 of the spring ll without the first spring 4 becoming inoperative, it suffices to completely press down the accelerator foot pedal which is hinged to the cable line 3. Thus the actuating lever will be displaced to such an extent (a process which is accompanied by the entrainment ofthe drag lever 8 or the free leg 13 of the spring 11 that the stop member 5 of the springy pawl member 6 again engages the drag lever 8.  
  There has been disclosed heretofore the best embodiment of the invention presently contemplated. However, it is to be understood that various changes and modifications may be made thereto without departing from the spirit of the invention.  
 What is claimed is:  
  1. A resetting device having a first spring. the action of which opposes the displacement of an actuating element, and a second prestressed spring for resetting the actuating element when the first spring is inoperative, said second spring being normally blocked and inoperative when the first spring is operative and being released when the first spring becomes inoperative, characterized by restraining means comprising a springy pawl member which prevents the engagement of said second spring with the actuating element only when the first spring is operative.  
  2. The resetting device according to claim 1 characterized in that said pawl member is in the form ofa leaftype spring which is loaded by the first spring and includes a stop member said stop member preventing the actuation of said second spring in the loaded state of said leaf-type spring.  
  3. The resetting device according to claim 2 further characterized by an entrainment device by means of which said second spring, after it is released engages the actuating element and displaces the actuating element in the same direction as the first spring.  
  4. The resetting device according to claim 3 wherein said second spring is in the form ofa tension spring and there is further provided a pivotable elongated drag lever secured to said tension spring, one extremity of said drag lever being in engagement with said stop member in the loaded state of said leaf-type spring when the first spring is operative, the other extremity of said drag lever including said entrainer device which is arranged to engage the actuating element when the first spring becomes inoperative and the drag lever is released by said stop member.  
  5. The resetting device according to claim 3 wherein said second spring is characterized by a free leg which is in engagement with said stop member in the loaded state of said leaf-type spring when the first spring is operative. said entrainer device being integral with the actuating element and arranged for engagement by said free leg of said second spring when the first spring becomes inoperative.  
  6. The resetting device according to claim 5 characterized in that the spring tension of said second spring is of substantially the same order of magnitude as the spring tension of the first spring.  
  7. A resetting device, for example for the throttle valve shaft of an automotive carburetor that is actuated through the movement ofa cable line, said resetting device comprising an actuating element coupled to the throttle valve shaft and responsive to movement of the cable line. a first spring member connected in tension to said actuating element, said first spring member being arranged to apply force of predetermined magnitude and direction to said actuating element which force is in opposition to the direction of movement of said actuating element that is in response to the movement of the cable line, a resilient pawl member, one portion of said pawl member being fixed while another portion of said pawl member is coupled to said first spring member and a second spring member arranged to apply a force to said actuating element that is of substantially the same order of magnitude and in substan tially the same direction as said first spring. said force of said second spring being applied to said actuating element only when said first spring is inoperative.  
  8. The resetting device according to claim 7 wherein there is further included a pivotable drag lever and a stop member. said second spring being in engagement with said drag lever, one end of said drag lever being in engagement with said stop when said first spring is operative, the other end of said drag lever including an entrainment device that is urged into engagement with said actuating element by said second spring only when said first spring is inoperative.  
  9. The resetting device according to claim 8 wherein said drag lever is mounted on the throttle valve shaft.  
  10. The resetting device according to claim 8 wherein said second spring is a tension spring.  
  11. The resetting device according to claim 8 wherein said stop member is integral with said pawl member.  
  12. The resetting device according to claim 7 wherein there is further included a stop and said second spring is an elongated strip having one end fixed and the other end free and in engagement with said stop when said first spring is operative. said actuating element including an entrainment device that is engaged by the free end of said second spring only when said first spring is inoperative.  
  13. The resetting device according to claim 12 wherein said second spring is in tension when it is in engagement with said stop.  
 14. The resetting device according to claim 12 wherein said stop is integral with said pawl member.