US3884206A

US3884206A - Centrifugal rpm regulator for internal combustion engines

Info

Publication number: US3884206A
Application number: US438416A
Authority: US
Inventors: Ernst Ritter
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1973-02-20
Filing date: 1974-01-31
Publication date: 1975-05-20
Anticipated expiration: 1992-05-20
Also published as: ES423386A1; ATA127574A; FR2218480A1; DE2308260A1; JPS5740334B2; FR2218480B1; DE2308260C2; SE399461B; SU524538A3; BR7401194D0; AT330509B; IT1008880B; IN138726B; GB1466877A; JPS49113933A

Abstract

In a centrifugal rpm regulator for fuel injected internal combustion engines, a fuel quantity control rod is provided which receives the forces associated with the displacements of an adapter sleeve which in turn is displaceable under the influence of centrifugal flyweights and as a function of engine rpm. The regulator has an adjustment device, including a pivotable lever, first and second elastically yieldable stops having respective adjustment springs, and an idle control spring, an operating lever, a guide lever, an intermediate lever and a forcetransmitting lever in addition to the adapter sleeve and the control rod. These structural elements in assembly cooperate so as to provide an idle and maximum speed rpm regulator in which the full-load fuel quantity supplied by the injection pump associated with the regulator can be adapted, by rpm-dependent regulating path changes, to the quantity which the engine can burn without polluting or for the maximum fuel quantity which may be required for a particular application. To this end, the regulator described provides for a variable adjustment of the path of travel of the control rod such that the control rod is shifted in the direction of a larger fuel supply quantity and then during higher rpm in the direction of a smaller fuel supply quantity or vice versa.

Description

Unite States Ritter atet [191 11] 3,84,26 [451 May 20, 1975 Ernst Ritter, Hattenbuhl, Germany [22] Filed: Jan. 31, 1974 [21] Appl. No.: 438,416

[75] Inventor:

[30] Foreign Application Priority Data Feb. 20, 1973 Germany 2308260 [52] US. Cl. 123/140 R; 123/140 J [51] Int. Cl. F02d 1/04 [58] Field of Search 123/140 R, 140 S [56] References Cited UNITED STATES PATENTS 3,139,875 7/1964 Link 123/140 R 3,426,739 2/1969 Bailey .1 123/140 R 3,435,812 4/1969 Kennell... 123/140 R 3,577,968 5/1971 Staudt 123/140 R 3,830,211 8/1974 Bechstein 123/140 R Primary Examiner-Charles J. Myhre Assistant Examiner-Ronald B. Cox Attorney, Agent, or Firm-Edwin E. Greigg [5 7 ABSTRACT In a centrifugal rpm regulator for fuel injected internal combustion engines, a fuel quantity control rod is provided which receives the forces associated with the displacements of an adapter sleeve which in turn is displaceable under the influence of centrifugal flyweights and as a function of engine rpm. The regulator has an adjustment device, including a pivotable lever, first and second elastically yieldable stops having respective adjustment springs, and an idle control spring, an operating lever, a guide lever, an intermediate lever and a force-transmitting lever in addition to the adapter sleeve and the control rod. These structural elements in assembly cooperate so as to provide an idle and maximum speed rpm regulator in which the full-load fuel quantity supplied by the injection pump associated with the regulator can be adapted, by rpm-dependent regulating path changes, to the quantity which the engine can burn without polluting or for the maximum fuel quantity which may be required for a particular application. To this end, the regulator described provides for a variable adjustment of the path of travel of the control rod such that the control rod is shifted in the direction of a larger fuel supply quantity and then during higher rpm in the direction of a smaller fuel supply quantity or vice versa.

4 Claims, 3 Drawing Figures 35 J1 I o =MT 39 38 T is, 0

' L0 25 ll y 1s 3 0u 3 b3 i l 1 3 56 27 So I ,55 M. '31. r I f 41.0

1; I I 1 H BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal rpm regulator for fuel injected internal combustion engines.

The centrifugal rpm regulator of the type under consideration has an adapter sleeve which is slidable under the influence of centrifugal flyweights, which in turn function in dependence on the engine rpm. The adapter sleeve transfers the forces associated with its regulatory motions over at least one intermediate lever to a fuel quantity control rod which adjusts the fuel supply quantity delivered by the fuel injection pump. The adapter sleeve also acts against a forcetransmitting member which operates under the influence of the force exerted by at least one regulating spring and is supported at one end against a stop which is mounted to the regulator housing. The centrifugal rpm regulator further contains an adjustment device which contains a pivotable lever connecting the adapter sleeve with the intermediate lever and being pivoted at one of its ends at least mediately to the intermediate lever. The pivotable lever contains two stop surfaces which engage two elastically yielding stops, the first of which has a first adjustment spring and the second of which has a second adjustment spring disposed in the force-transmitting member.

2. Description of the Prior Art Injection engines, especially those for driving motor vehicles, operate in a wide rpm range. The fuel injection pumps installed in these engines are in many cases provided with regulators (governors) which, in addition to regulating engine rpm, also change the maximum fuel quantity set for full load operation within as wide an rmp range as possible. This is accomplished in such a way that the maximum fuel quantity corresponds or very nearly corresponds (adjusted) to the fuel supply quantity curve demanded by the engine and predetermined for a smokeless combustion or for a particular application.

For the adjustment of the maximum fuel quantity supplied by the injection pump to the full-load characteristic of the motor, known rpm regulators of the type described above contain an adjustment device consisting of two spring seats and one pivotable lever. The adjustment device makes possible an adjustment curve which varies as a function of rpm, i.e., the maximum fuel quantity can be changed in the direction of smaller as well as of large quantities during increasing rpm. It is, therefore, possible using this device to realize a bent fuel supply quantity curve as a function of rpm. i.e., a curve which first increases and then decreases, or first decreases and then increases. These known rpm regulators operate only as so-called adjusting rpm regulators in which, depending on the position of the operating lever, any desired rpm lying between idle and maximum rpm can be set.

For use in motor vehicles, however, it is preferable to employ a so-called idle and maximum rpm regulator according to which the idle rpm is set in one end position of the operating lever, while in the intermediate position and the other end position of the operating lever a particular fuel quantity is set. The regulator also limits the maximum rpm, which is predetermined by a maximum rpm regulating spring.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to develop a centrifugal rpm regulator of the type described above which operates as an idle and maximum rpm regulator, and according to which a varying adjustment curve with respect to rpm, as required in modern fuel injection engines, can be realized in a simple way.

This and other objects are accomplished according to the present invention by providing an intermediate lever configured, in a known manner, as a two-armed slotted lever, with its pivot point being guided in the slot by a guide lever, the intermediate lever being changeable in dependence on the pivotal position of an operating lever; and further, by providing that two stop surfaces of the pivotable lever pivoted eccentrically with respect to the adapter sleeve are arranged facing away from each other at the level of the axis of the adapter sleeve between the two stops, where one of the stops is pretensioned by a first adjustment spring and is carried centrally within the adapter sleeve and where the other stop is pretensioned by a second adapter spring and also by an idle control spring and is carried as an extension of the axis of the adapter sleeve in the force-transmitting member, with the latter being acted upon by a maximum rpm regulating spring which is at least mediately supported within the regulator housing.

A preferred embodiment of the present invention is such that the adapter sleeve has a bearing arm connected to its end facing away from the centrifugal flyweights, with this bearing arm extending beyond the periphery of the adapter sleeve and being fixedly connected with it, with one end of the pivotable lever being pivoted to the bearing arm.

In order to reduce the influence of friction and wear on the individual parts during the adjustment function, in an advantageous embodiment of the present invention the adapter sleeve is guided at its end facing away from the centrifugal flyweights by two laterally protruding studs within the guiding arms of the forcetransmitting member, and its end facing toward the centrifugal flyweights is guided in a cylindrical guide connected with the drive shaft.

A further embodiment of the present invention is such that the pivotable lever has a path-limiting stop cooperating with an opposite stop on the adapter sleeve and where the first adjustment spring attempts to hold the path-limiting stop in contact with the counterstop. In this way, the rest position of the pivotable lever is singularly determined and any influence of the one stop onto the other is avoided.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view in elevation illustrating a longitudinal section through the centrifugal rpm regulator according to the present invention.

FIG. 2 is a cross-sectional view taken along the line Il-II of FIG. 1 within the region of the adjustment device.

FIG. 3 illustrates a diagram with two possible adjustment curves.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIG. 1, there is shown a drive shaft 10 of an injection pump (not shown), the injection pump being used with an internal combustion engine.

On the shaft there is fastened a centrifugal flyweight regulator 11 whose pivotally mounted centrifugal flyweights 12 have arms 13 which act on the front surface 14 of a thrust bearing 15. The thrust bearing 15 is mounted on an extension of an adapter sleeve 16 and transmits the adjustment forces of the centrifugal flyweights 12 to the adapter sleeve 16. The adapter sleeve 16 is itself slidably supported with one of its ends 16a on a cylindrical guide 17, formed as a stud or boss of the drive shaft 10, and with its other end 16b, which faces away from the centrifugal flyweights 12 and the drive shaft 10, being provided with laterally extending guide studs 18, each of which is guided in a guide slot 19 of a force-transmitting lever 20 which serves as a force-transmitting member (see FIG. 2).

The force-transmitting lever 20 is pivotably mounted on a bearing bolt 21 fixedly attached to the housing 23. In FIG. 1, the lever 20 is shown in its vertical normal or rest position which is determined by a stop 22 fixed within the housing 23. The stop 22 is formed by the frontal surface of an abutment screw 24 which is screwed into the regulator housing 23. The forcetransmitting lever 20 has two guide arms 25 in the region of the axis of the adapter sleeve 16 which laterally envelop the adapter sleeve 16 and have the guide slots 19, which are open in the direction of the centrifugal weight regulator, machined therein. A maximum rpm regulating spring 27, supported in the regulator housing 23 through the action of an adjustable counterbearing 26, holds the force-transmitting lever 20 in a known fashion in the position shown as long as, or until, the force due to the centrifugal flyweights l2 and exerted by the adapter sleeve 16 onto the force-transmitting lever 20 is greater than that of the maximum rpm regulating spring 27.

Fixedly connected to the adapter sleeve 16 is a bearing arm 28 (see FIG. 1) which extends out beyond the outer circumferential surface of the adapter sleeve 16 with one end a of a pivotable lever 30 being pivoted to the bearing arm 28 by means of a pin 29 and with the other end 30b of the pivotable lever 30 being connected, by means of a ball joint 31 and through the intermediate insertion of a reversing lever 32, with an intermediate lever 33. The reversing lever 32 is supported in a bearing point 34 in the regulator housing 23, and serves in a known fashion for the motion reversal of the control motions transmitted from the adapter sleeve 16 to the intermediate lever 33. In this way, a control rod 35, serving as the fuel quantity adjustment member of the fuel injection pump, is moved in the direction of the arrow S for the purpose of reducing the fuel supply quantity of the fuel injection pump (stop motion), the control rod 35 being connected to the intermediate lever 33 by means of an elastically yieldable shackle 58. The intermediate lever 33 is configured as a two-armed slotted lever, whose pivotal point 37 is guided in a slotted guide 36. The pivotal point 37 is changeable, depending upon the pivotal position of an operating lever 38, for the purpose of changing the fuel supply quantity to be adjusted by the control rod 35. A pin 37 serves as the pivotal point 37 and extends in a known fashion from a guide lever 39 which is fixedly connected with the operating lever 38 via a setting shaft 40 borne in the regulator housing 23.

The pivotable lever 30, which is pivotably and eccentrically attached to the adapter sleeve 16 and which connects the adapter sleeve 16 mediately with the slotted intermediate lever 33, has two mutually

opposing stop surfaces

41 and 42 at the level of the axis of the adapter sleeve 16 (FIG. 2) which are engaged by two elastically yielding

stops

43 and 44, so that the pivotable lever 30 is fixedly tensioned between the two stops.

One stop 43, pretensioned by a first adjustment spring 45, has a stop bolt 43a which is guided centrally in a blind bore 46 within the adapter sleeve 16. The adjustment distance which can be traversed by the stop bolt 43a is designated by a in FIG. 1 and is determined by the length of the stop bolt 43a and also by its starting position which is fixed by a path limiting stop 47. These are two path-limiting stops 47 present and these form part of the two arms 48 forming part of the pivotable lever 30 which laterally envelop the adapter sleeve 16. The first adjustment spring attempts to hold the path-limiting stops 47 in contact with the studs 18 of the adapter sleeve 16, the studs 18 serving thereby as counterstops.

The second stop 44 is disposed in the forcetransmitting lever 20 as an extension of the axis of the adapter sleeve 16. It has a stop bolt 440 which engages the stop surface 42 of the pivotable lever 30 (see FIG. 2) as a result of the pretension force of a second adjustment spring 49 and of an idle regulating spring 50. Between the adjustment spring 49 and the idle regulating spring 50, a sleeve 51 is installed. The sleeve 51 is mounted on the stop bolt 44a within a bore 54 of a threaded bushing 55, which in turn is screwed into the force-transmitting lever 20. The sleeve 51 has a shoulder 52 which is spaced from a bottom surface 53 of the bore 54 by a distance which determines the stroke b (see FIG. 1) of the adapter sleeve 16. In the normal rest position, shown in FIGS. 1 and 2, of the stop 44, the pretension force of the second adjustment spring 49 presses the sleeve 51 against a snap ring 57 fastened on the stop bolt 44a, while the pretension force of the idle control spring holds the snap ring 57 in contact with the threaded bushing 55..The installed position of the threaded bushing 55 within the force-transmitting lever 20 is adjustable and can be fixed by a lock nut 56. The remaining portion of the stroke left over after the idle stroke b up to the contact of the pivotable lever 30 with the threaded busing 55 is traversed within an rpm domain described in more detail below and against the force of the second adjustment spring 49. This remaining portion is designated by the displacement c.

The elastically yielding shackle 58, which is installed between the slotted intermediate lever 33 and the control rod 35, makes it possible to equalize for path differences of the regulating parts which result from the fact that, in certain operating regions and in a manner not shown in detail, the control rod 35 can make contact at its stop before the slotted intermediate lever 33 has completed its regulatory motion.

The exemplary embodiment of the present invention 4 described in FIGS. 1 and 2 represents an idle and maximum speed rpm regulator in which the full-load fuel quantity of the injection pump can be adapted, by rpmdependent regulating path changes, to the quantity which the engine can burn smokelessly or for the maximum fuel quantity which may be required for a particular application. Such an embodiment contains, therefore, a so-called variable adjustment, i.e., the direction of the control path change is dependent on the rpm. For example, it can be required that, in a first instance,

the control rod of the injection pump is shifted in the direction of a larger fuel supply quantity and then, subsequently, during higher rpm, it is shifted in the direction of a smaller fuel supply quantity. A reverse process of adjustment can also be required.

The two adjustment processes mentioned above, which change the adjustment direction (sense of adjustment) during increasing rpm, are shown in the diagram of FIG. 3 where the abscissa designates the rpm n and the ordinate shows the position of the control and R. It is assumed in this that the position of the control rod R is a measure of the fuel supply quantity Q delivered by the injection pump. In that case, these adjustment curves also represent the supply quantity as a function of rpm, and the ordinate therefore also shows Q. The dashed lines A-B-C show the regulatory path change in the lower rpm range, when the regulator controls an excess fuel quantity required for starting. The solid lines D-E-F-G, drawn between the rpms n1 and n4 are designated by I and show an adjustment process in which the fuel supply quantity increases between the rpms n1 and n2, namely from the point D to the point E; subsequently, between n2 and n3, it is constant between the points E and F; and between the rpms n3 and n4 it decreases from point F to point G. Exactly the opposite adjustment process II is shown by the dashed lines D-I-I-K-G drawn between the rpms n1 and n4.

The length of the path A-B is determined by the pretension of the idle control spring 50 which serves at the same time as the starting spring.

In the following the method of operation of the regulator is described with particular emphasis on the operation of the adjustment system consisting substantially of the pivotable lever 30, the

stops

43 and 44, and their adjustment springs 45 and 49.

FIG. 1 shows all regulator parts in their rest, i.e., stop, position. In order to start the internal combustion engine, the operating lever 38, and therefore also the guide lever 39, is turned in the counterclockwise sense by an amount determined by a full load limiting stop (not shown). With the reversing lever 32 stationary, the slotted intermediate lever 33 is pivoted to the left and the control rod 35 is pushed in the direction of arrow V into the starting position designated by A in FIG. 3. This starting position is retained up to an rpm corresponding to the rpm at point B in FIG. 3, and if the rpm increases further, the starting quantity is reduced to the fuel supply quantity of the control rod position designated by the point C. In this process, the stop bolt 44a, together with the sleeve 51, yields to the right in opposition to the force of the idle control spring 50 and under the effect of the force of the centrifugal flyweights 12 until such time as the shoulder 52 of the sleeve 51 touches the bottom surface 53 of the threaded bushing 55. In all this, the pivotable lever 30, which is under the influence of the pretension of the first adjustment spring 45 and which is held against the studs 18 by the stop bolts 43a and its path-limiting stop 47, acts as a rigid member of the adapter sleeve 16, so that, together with the stop bolt 44a, the ball joint 31 is moved to the right by the amount of the idle stroke b. In this way and in a known fashion, the reversing lever 32 is thus pivoted about its bearing point 34 so that the slotted intermediate lever 33 is pivoted in a clockwise sense about its pivotal point 37, and the control rod 35 is thereby pushed in the direction of arrow S. The position of the control rod demonstrated by the path C-D in FIG. 3 is retained up to the rpm n1. The pretension of the first adjustment spring 45 is chosen so that when the rpm increases further, beyond n1, the first adjustment spring 45 is compressed by the adapter sleeve 16 by an amount a (FIG. 1) up to an rpm n2. Since the bearing arm 28 and the pin 29 serving as the pivotal point for the pivotable lever 30 has moved by the same amount a and since the stop 44 does not yield on account of the larger pretension of the second adjustment spring 49, the pivotable lever 30 pivots about its pin 29 in the clockwise sense and the ball joint 31 moves toward the centrifugal flyweights 12. This motion of the ball joint 31 is transmitted'by the slotted intermediate lever 33 to the control rod 35 in such a way that it moves in the direction of the arrow V, i.e., in the direction of larger fuel quantities. This process corresponds to the curve D-E in FIG. 3. The pretension of the second adjustment spring 49 is chosen in such a way that the setting force exerted by the centrifugal flyweights 12, via the adapter sleeve 16, overcomes this pretension of the adjustment spring 49 only when rpm n3 is reached. Therefore, the position of the control rod 35 is retained between the points E and F in FIG. 3. When the rpm increases beyond the value of n3, the second adjustment spring 49 yields and the stop bolt 44a moves by the amount c (FIG. 1) up to the rpm value n4. During this process, the adapter sleeve 16 and the pivotable lever 30 cover the same distance because when the first adjustment spring 45 is compressed, the adapter sleeve 16 and the pivotable lever 30 are to be regarded as a rigid structural part and the ball joint 31 is moved to the right, away from the centrifugal flyweights 12. In this way, the control rod 35 is pushed in the direction of the arrow S, corresponding to the curve F-G in FIG. 3, in the direction of a smaller fuel supply quantity. At this point, the stop surface 42 of the pivotable lever 30 engages the threaded bushing 55, which is screwed into the force-transmitting lever 20, and when the rpm increases further beyond the value of n4, the force-transmitting lever 20 yields in opposition to the spring force of the maximum speed regulating spring 27 and the regulator regulates in a known fashion downwardly (see curve G-L in FIG. 3). During this process, the control rod 35 is shifted in the direction of arrow S until it reaches its stop position.

The adjustment process II represented by the dashed lines D-I-I-K-G can be achieved by the same regulator if the pretension of the first adjustment spring 45 is chosen to be greater than that of the second adjustment spring 49. In that case, the adjustment stroke designated by c is traversed before the adjustment stroke designated by a.

By blocking one of the two stops 43, 44 or by replacement of one of these two stops with a fixed stop, it is possible to realize, depending on the requirements, either only an increasing or only a decreasing adjustment process (not shown).

That which is claimed is:

1. In a centrifugal rpm regulator for fuel injected internal combustion engines including a housing mounting, centrifugal weight means, an adapter sleeve slidably displaceable under the influence of the centrifugal weight means and as a function of engine rpm, a twoarmed intermediate lever, a fuel quantity control rod, the adapter sleeve transmitting the forces associated with its controlled motions resulting from its slidablc displacement through the intermediate lever to the fuel quantity control rod for adjusting the fuel quantity de livered by an injection pump used in conjunction with 'the regulator, a force-transmitting lever, stop means mounted to the housing against which one end of the force-transmitting lever is supported, and atleast one regulating spring supported in the housing and exerting a force against the force-transmitting lever, the adapter sleeve being mounted so as to also act against the forcetransmitting lever, the improvement comprising:

A. an adjustment device having:

a. a pivotable lever connecting the adapter sleeve with the intermediate lever, said pivotable lever being pivoted at one of its ends at least mediately to the intermediate lever and eccentrically with respect to the adapter sleeve and including two stop surfaces;

b. a first elastically yieldable stop means having a first adjustment spring;

c. a second elastically yieldable stop means having a second adjustment spring, said first and second stop means engaging respective ones of said stop surfaces; and

d. an idle control spring;

B. an operating lever; and

C. a guide lever, and wherein the adapter sleeve defines a central bore and axis;

the intermediate lever has a slot in one of its arms;

said guide lver has a pin at one end thereof which serves as the pivot pin for the intermediate lever, said pin being engageable within said slot;

said operating lever being pivotably mounted to the housing and engageable with said guide lever so that the position of the intermediate lever is changeable in dependence on the pivotal position of said operating lever;

said stop surfaces being arranged at the level of the adapter axis between said first and second stop means and facing away from each other;

said first stop means being pretensioned by said first adjustment spring and being mounted within the control bore of the adapter sleeve;

said second stop means being pretensioned by said second adjustment spring and said idle control spring and being mounted to an extension of the force-transmitting member; and

said regulating spring serves as a maximum rpm spring which is at least mediately supported within the housing.

2. The regulator as defined in claim 1, wherein the adapter sleeve includes a bearing arm connected to the end of the adapter sleeve facing away from the centrifugal weight means said bearing arm extending beyond the circumferential outer surface of the adapter sleeve, and wherein one end of said pivotable lever is mounted to said bearing arm for pivotal movement relative thereto.

3. The regulator as defined in claim 1, further comprising a drive shaft and a cylindrical guide mounted thereto, wherein the force-transmitting member includes two guiding arm portions having slots defined therein, wherein the adapter sleeve is provided at its end facing away from the centrifugal weight means with two laterally extending studs which engage a respective one of said slots, and wherein the adapter sleeve has its end facing toward the centrifugal weight means guided within said cylindrical guide so that the friction and wear on the individual elements of the regulator are reduced.

4. The regulator as defined in claim 1, wherein said pivotable lever includes path-limiting stop means and the adapter sleeve is provided with an opposite stop means which is engageable with said path-limiting stop means, and wherein said first adjustment spring biases said path-limiting stop means into engagement with said opposite stop means.

Claims

1. In a centrifugal rpm regulator for fuel injected internal combustion engines including a housing mounting, centrifugal weight means, an adapter sleeve slidably displaceable under the influence of the centrifugal weight means and as a function of engine rpm, a two-armed intermediate lever, a fuel quantity control rod, the adapter sleeve transmitting the forces associated with its controlled motions resulting from its slidable displacement through the intermediate lever to the fuel quantity control rod for adjusting the fuel quantity delivered by an injection pump used in conjunction with the regulator, a force-transmitting lever, stop means mounted to the housing against which one end of the force-transmitting lever is supported, and at least one regulating spring supported in the housing and exerting a force against the force-transmitting lever, the adapter sleeve being mounted so as to also act against the force-transmitting lever, the improvement comprising: A. an adjustment device having: a. a pivotable lever connecting the adapter sleeve with the intermediate lever, said pivotable lever being pivoted at one of its ends at least mediately to the intermediate lever and eccentrically with respect to the adapter sleeve and including two stop surfaces; b. a first elastically yieldable stop means having a first adjustment spring; c. a second elastically yieldable stop means having a second adjustment spring, said first and second stop means engaging respective ones of said stop surfacEs; and d. an idle control spring; B. an operating lever; and C. a guide lever, and wherein the adapter sleeve defines a central bore and axis; the intermediate lever has a slot in one of its arms; said guide lver has a pin at one end thereof which serves as the pivot pin for the intermediate lever, said pin being engageable within said slot; said operating lever being pivotably mounted to the housing and engageable with said guide lever so that the position of the intermediate lever is changeable in dependence on the pivotal position of said operating lever; said stop surfaces being arranged at the level of the adapter axis between said first and second stop means and facing away from each other; said first stop means being pretensioned by said first adjustment spring and being mounted within the control bore of the adapter sleeve; said second stop means being pretensioned by said second adjustment spring and said idle control spring and being mounted to an extension of the force-transmitting member; and said regulating spring serves as a maximum rpm spring which is at least mediately supported within the housing.