CONTROL DEVICE FOR A VERTICAL SHAFT TYPE ENGINE

Abstract: An improved control device for a vertical shaft type engine (100), in which control of the engine is effected by means of a single manipulation lever from stoppage to choking is disclosed herein. The improvements exist in that a control lever is constructed of a first control lever (122) and a second control lever (126) which are relatively rotatable and can rotate jointly within a predetermined range, the first control lever is connected to a governor spring (153) and is rotatable between an engine stop switch terminal (119) and a highest speed rotation regulating screw (121), the second control lever is provided with a connecting section (126e) with a Bowden wire which is in turn connected to a manipulation lever on a working machine, a pair of engaging sections (126a,b) with the first control lever phase-­ shifted by 180° and a pair of contact sections (126c,d) with a choke lever phase-shifted by 180° so that the direction of movement of the connecting point between the second control lever and the Bowden wire can be reversed by remounting the second control lever as phase-shifted by 180°, and clamp sections (130) for the Bowden wire are provided on the second control lever at two locations on the left and right sides, respectively, that is, at four locations in total.

Description: BACKGROUND OF THE INVENTION: Field of the Invention: The present invention relates to a control assembly of the type defined by the precharacterizing features of claim 1. Description of the Prior Art: Among lawn mowers on which a vertical shaft type engine is mostly mounted, in many of them control of the engine is effected by means of single manipulation lever, and so, an engine control device provided with all the functions of stoppage, rotational speed regulation and choking, is necessitated. In the prior art, as shown in Fig. 7, the control assembly of the type defined at the preamble and i.e. known from the US-A-4 490 309 has such structure that a control lever 3 is rotatably mounted on a control panel 9 on which a stop switch terminal 10 is equipped, and one end of the control lever 3 can be brought into contact with a choke control plate 4. A Bowden wire 1 has its outer cable fixedly secured to the control panel 9 by means of a wire clamp 8. An inner cable 2 of the Bowden wire 1 is moved in the forward and backward directions by manipulating a manipulation lever 21 on a working machine H as shown in Figs. 8 and 9, and one end of the inner cable 2 is connected to the control lever 3 (Fig. 7). When the control lever 3 has come closest to the wire clamp 8(A), it comes into contact with the stop switch terminal 10 to stop an engine E as shown in Fig. 7, while at the farthest position from the wire clamp 8(A), a rotational speed regulating screw 6 provided on the control lever 3 comes into contact with the choke control plate 4 and rotates the choke control plate 4, and the construction is such that a choke valve in a carburettor not shown is closed by a choke rod 5 connected to the choke control plate 4. A rotational speed of the engine E is controlled by expanding and contracting a governor spring 7 engaged with the control lever 3 in accordance with rotation of the control lever 3, thus moving a governor lever (not shown) engaged with the other end of the governor spring 7 and regulating an opening angle of a carburettor throttle valve (not shown) connected to the governor lever. When the control lever 3 is close to the stop switch terminal 10 of the engine E, the engine E rotates at a low speed, but just before the control lever 3 comes into contact with the choke control lever 4, the engine becomes to rotate at a high speed. With regard to the manipulation lever 21 on the working machine H for controlling the engine E, there is a lever 21 of the type that engine E is accelerated to a high speed when the inner cable 2 of the Bowden wire 1 is moved in the direction of projecting as shown in Fig. 9, and there is a lever 21 of another type that the engine E is accelerated to a high speed when the inner cable 2 of the Bowden wire 1 is moved in the direction of retracting. Consequently, in the case of a control device having such structure that when a manipulation lever 21 on a working machine H is manipulated in the direction of projecting an inner cable 2 of a Bowden wire 1, the engine E is accelerated to a high speed as shown in Fig. 9, a wire clamp position with respect to the control panel 9 is selected at 8(A) in Fig. 7, while in the case of a control device having such structure that when the manipulation lever 21 on the working machine H is manipulated in the direction of retracting the inner cable 2 of the Bowden wire 1, the engine E is accelerated to a high speed, the wire clamp position with respect to the control panel 9 is selected at 8(B) in Fig. 7. In Fig. 8 are shown two examples of an attitude of mounting of an engine in the prior art, in the case where the engine E is choked when the manipulation lever 21 of the working machine H is manipulated in the direction of projecting the inner cable 2 of the Bowden wire 1. Since the stop switch terminal 10 is located in the direction of mounting of an ignition plug 22 on the engine E, in order to minimize the routing length of the inner cable 2 of the Bowden wire 1 on the working machine H, possible attitudes of mounting of an engine are only the two varieties shown in Figs. 8(a) and 8(b), respectively. In the engine control device in the prior art in which an engine is manipulated from ″stoppage″ to ″choking″ by means of a single Bowden wire, there was a disadvantage that in order to simplify routing of the Bowden wire 1 a mounting attitude of an engine is restricted depending upon a direction of manipulation of a manipulation lever 21 on a working machine H, that is, depending upon whether the engine is accelerated to a high speed when the inner cable 2 of the Bowden wire 1 projects or it is accelerated to a high speed when the inner cable 2 is retracted, as described above. In the case where the working machine H has such structure that it is accelerated to a high speed when the inner cable 2 projects, the mounting positions of the engine as shown in Figs. 8(a) and 8(b) are determinative and it was difficult to select the position of the ignition plug 22 as directed in the travelling direction of the working machine for the purpose of facilitating maintenance service. SUMMARY OF THE INVENTION: It is therefore the object of the present invention to provide an improved control assembly of the Kind defined at the preamble, which makes it possible to arbitrarily select a mounting attitude of the engine on a working machine regardless of a structure of a manipulation lever on the working machine, and which is advantageous for design and maintenance service. This object is attained by the characterizing features of claim 1. Advantageous developments of the inventions are given by the features of the sus claims. According to the present invention, a mounting attitude of an engine can be arbitrarily selected regardless of the structure of a manipulation lever on a working machine, and hence, maintenance and service for an engine when it is mounted on a working machine, become easy. The above-mentioned object, features and advantages of the present-invention will become more apparent by reference to the following description of one preferred embodiment of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS: In the accompanying drawings, Figs. 1 to 6 show one preferred embodiment of the present invention, while Figs. 7 to 9 show one example of a control device in the prior art, wherein: Fig. 1 is a plan view of a vertical shaft type engine in connection to which the control assembly according to the present invention is used; Fig. 2 is a side view of the same engine as viewed in the direction of arrow II in Fig. 1; Fig. 3 is a disintegrated perspective view of the control assembly according to the invention used in the same engine as viewed in the direction of arrow III in Fig. 1; Fig. 4 is a partial cross-section view of the same control assembly as viewed in the direction of arrow IV in Fig. 2 (omitting a control panel cover 30); Fig. 5 is a partial side view of the same control assembly as viewed in the direction of arrow V in Fig. 4; Fig. 6 is a schematic view showing different states of mounting of the control assembly shown in Figs. 1 to 5; Fig. 7(a) is a front view of the control assembly in the prior art; Fig. 7(b) is a schematic view showing a state of mounting the control assembly in Fig. 7(a) on an engine; Fig. 8 is a plan view showing different states of mounting the control assembly in Fig. 7(a) on a working machine; and Fig. 9 is an enlarged perspective view showing a structure of a manipulation lever on a working machine. DESCRIPTION OF THE PREFERRED EMBODIMENT: Now description will be made on one preferred embodiment of the present invention with reference to Figs. 1 through 6. As shown in Figs. 1 and 2, an engine 100 is a vertical shaft type air-cooled general purpose engine, which is composed of an air cleaner 101, a fuel tank 102, a recoil starter 103, a muffler 104, a carburettor 105, a cylinder 106, an ignition plug 107, an output shaft 108, a control device 109 and the like. With regard to the control device 109 which forms an essential part of the present invention, it will be described in detail with reference to Figs. 3 to 5. A control panel 112 serving as a medium for mounting the control device 109 to an engine E, is fixedly secured to the engine E by means of bolts 111 and 114. Onto this control panel 112 is mounted a stop switch terminal 119 via an insulator 118, a choke lever 116 is rotatably mounted onto the panel 112 by means of a screw 149, a spacer 110, a washer 150 and a nut 151, furthermore a choke rod 152 adapted to be connected with the carburettor 105 is mounted on the choke lever 116, and a return spring 117 is stretched between the control panel 112 and the choke lever 116 in order that the choke lever 116 keep a choke valve not shown in the carburettor opened except for the time when it is necessitated to close the choke valve. In addition, a first control lever 122 for controlling a rotational speed of the engine E is sandwiched between spacers 115 and 123 both made of resin for reducing friction upon rotation, it is associated with a second control lever 126 under the condition that a return spring 124 interposed therebetween for joint movement is applied with initial loading, and they are fixedly assembled so as to be freely rotatable by means of screw washers 127, 141 and 140 and a nut 142. On the first control lever 122 is mounted a governor spring 153 for regulating an opening angle of a throttle valve in the carburettor in order to maintain a rotational speed of the engine constant independently of a loading condition, and a contact end portion 122a of the first control lever 122 is adapted to come into contact with the stop switch terminal 119 when the first control lever 122 is rotated in the anticlockwise direction as viewed in Fig. 3. On the other hand, when the first control lever 122 is rotated in the clockwise direction as viewed in Fig. 3, another contact end portion 122b of the first control lever 122 is adapted to come into contact with a regulating screw 121 which restricts the highest rotational speed of the engine, and thereby the rotational speed of the engine is controlled. The second control lever 126 to which one end of the inner cable 2 of the Bowden wire 1 in the control device according to the present invention is connected at a hole 126e, is formed in such manner that it can be mounted in two alternative set conditions which are phase-shifted by 180° from each other. Under a first set condition, an abutment member 122c of the first control lever 122 is engaged with an engaging section 126a of the second control lever 126, hence when the second control lever 126 rotates in the clockwise direction as viewed in Fig. 3, the first control lever 122 is jointly rotated due to the initial loading of the return spring 124, and after the first control lever 122 has been brought into contact with the highest speed regulating screw 121 and has been restricted in rotation, the engaging section 126a of the second control lever 126 is separated from the abutment member 122c of the first control lever 122, only the second control lever 126 rotates, then a contact section 126c with the choke lever 116 of the second control lever 126 comes into contact with a folded section 116a of the choke lever 116, and thereby the choke lever 116 is rotated in the clockwise direction as viewed in Fig. 3. It is to be noted that the rotation of the second control lever 126 is restricted by a slot 130a or 130b in a control panel cover 130. Whereas, under a second set condition where the second control lever 126 is set as phase-shifted by 180° with respect to the first control lever 122, the second control lever 126 is engaged with the abutment member 122c of the first control lever 122 at an engaging section 126b phase-shifted relative to the first mentioned engaging section 126a by 180° about the axis of rotation of the control levers 122, 126, and engaged with the folded section 116a of the choke lever 116 at the contact section 126d, and therefore, it becomes possible to change the position where the Bowden wire 1 in the control device according to the present invention is mounted to a mounting hole 126e in the second control lever 126 projecting from the control panel cover 130, by appropriately selecting the orientation of the second control lever 126 assembled with the first control lever 122. Therefore, as shown in Fig. 3, in the control panel cover 130 are formed threaded holes 130e, 130f, 130g and 130h for clamping the outer cable of the Bowden wire at two locations on the left and right sides, respectively, that is, at four locations in total corresponding to the slots 130a and 130b so that the outer cable of the Bowden wire can be clamped at any one location among these four locations by means of a wire clamp 131 and a screw 132. In Fig. 6(a), reference characters E, F, G and H designate the clamp positions at the above-mentioned four locations. Figs. 6(a) and 6(b) illustrate the cases where the engine is mounted with the position of the ignition plug 22 directed in the travelling direction of the working machine, Fig. 6(a) showing a control device having such structure that the engine is accelerated to a high speed when the manipulation lever on the working machine is moved in the direction of projecting the inner cable 2 of the Bowden wire 1, while Fig. 6(b) showing a control device having such structure that the engine is accelerated to a high speed when the manipulation lever on the working machine is moved in the direction of retracting the inner cable 2 of the Bowden wire 1. Figs. 6(c) and 6(d) illustrate the case where the engine is mounted with the position of the ignition plug 22 directed in the leftward direction with respect to the travelling direction of the working machine, Fig. 6(c) showing a control device having such structure that the engine is accelerated to a high speed when the manipulation lever on the working machine is moved in the direction of projecting the inner cable 2 of the Bowden wire 1, while Fig. 6(d) showing a control device having such structure that the engine is accelerated to a high speed when the manipulation lever on the working machine is moved in the direction of retracting the inner cable 2 of the Bowden wire 1. The set condition of the second control lever 126 and the clamped position of the Bowden wire 1 in each case are as shown in the corresponding figure, and under the illustrated condition the inner cable 2 of the Bowden wire 1 is connected to the hole 126e in the second control lever 126. Under the set condition where the second control lever 126 projects from the slot 130b in the control panel cover 130 with the ignition plug 22 directed in the travelling direction, when the second control lever 126 rotates in the clockwise direction, the engine is controlled sequentially in the mode of "stoppage" → "low speed" → "high speed" → "choking" (Fig. 6(b)). Also, under the set condition where the second control lever 126 projects from the slot 130a in the control control panel cover 130 with the ignition plug directed in the travelling direction, when the second control lever 126 rotates in the clockwise direction, the engine is controlled sequentially in the mode of "stoppage" → "low speed" → "high speed" → "choking" (Fig. 6(a)). Under both the above-mentioned two exemplified conditions, as a result of rotation of the second control lever 126 in the clockwise direction the engine takes similar operating conditions sequentially in the mode of "stoppage" → "low speed" → "high speed" → "choking", but the directions of movement of the connecting point 126e between the second control lever 126 and the inner cable 2 are opposite to each other for the respective conditions. The same is also true when the set conditions illustrated in Figs. 6(c) and 6(d) where the engine is mounted with the ignition plug 22 directed in the leftward direction, are compared with each other. Therefore, according to the present invention, since the attitude of mounting of the engine is not subjected to any restriction independently of the structure of a manipulation lever in a working machine such as a lawn mower, facility in maintenance for an ignition plug or a control device is not deteriorated and also routing of a Bowden wire can be simplified. As described in detail above, in the control assembly according to the present invention it is possible to reverse the direction of movement of a control wire for an engine by merely modifying a method of assembling same component parts, an attitude of mounting of an engine can be arbitrarily chosen regardless of a structure of a manipulation lever on a working machine, and therefore, facility in maintenance for a control device, an ignition plug and the like can be improved.

Claims: 1. A control assembly for controlling the operation between stopping and choking, of a vertical shaft type engine (100, E) to be mounted on a working machine and having an engine stop switch terminal (119) and a carburretor (105) including a choke valve and a throttle valve, said control assembly comprising a choke lever (116) to be mounted on the engine (100, E) in operable connection with the choke valve for rotating between a non-choking position and a choking position, a control device (109) to be rotatably mounted on the engine (100, E) for cooperation with said choke lever (116), the throttle valve and the engine stop switch terminal (119), a Bowden wire (1) including an outer cable to be fixedly mounted on the enigne (100, E) and an inner cable (2) movable relative to said outer cable, said inner cable (2) having a first end connected to said control device (109) and a second end, and a single accelaration control lever connected to said second end of said inner cable (2) and to be mounted on the working machine, characterized in that said control device (109) comprises: a first control lever (122) to be mounted on the engine (100, E) for rotation in a direction of increasing engine speed between an engine stop position, whereat a contact end portion (122a) of said first control lever (122) operates the engine stop switch terminal (119) to stop the engine (100, E), and a highest engine speed rotation position defined by a regulating screw (121), whereat further rotation of said first control lever (122) is prevented, said first control lever (122) to be operatively connected to the throttle valve to change the engine speed in response to rotation of said first control lever (122) in said direction of increasing engine speed, and said first control lever (122) having an abutment member (122c), a second control lever (126) having a connecting portion (126e) connected to said first end of said inner cable (2) of said Bowden wire (1), said second control lever (126) to be mounted on the engine (100, E) for rotation about an axis of rotation in response to manipulation of said single accelaration control lever and having a pair of engaging sections (126a, 126b) phase-shifted relative to each other by 180° about said axis of rotation and a pair of contact sections (126c, 126d) phase-shifted relative to each other by 180° about said axis of rotation, said second control lever (126) being rotatable about said axis of rotation in said direction of increasing engine speed between a first position, whereat said abutment member (122c) of said first control lever (122) engages a first said engaging section (126a) of said second control lever (126), and a second position, whereat a first said contact section (126c) of said second control lever (126) moves said choke lever (116) to said choking position, said second position being beyond said highest engine speed rotation position of said first control lever (122) in said direction of increasing engine speed, means (124) for, upon said second control lever (126) being rotated in said direction of increasing engine speed from said first position toward said second position, causing said first control lever (122) to be rotated with said second control lever (126) between said engine stop position and said highest engine speed rotation position, said second control lever (126) being remountable in an alternative orientation with said connecting portion (126e) phase-shifted relative to said first control lever (122) by 180° about said axis of rotation, such that said abutment member (122c) of said first control lever (122) engages a second (126b) said engaging section of said second control lever (126) at said first position of said second control lever (126) and a second (126d) said contact section of said second control lever (126) moves said choke lever (116) to said choking position at said second position of said second control lever (126), and means (130, 130e-h, 131, 132) for mounting said outer cable of said Bowden wire (1) at four alternative locations (E, F, G, H), depending on the orientation of said second control lever (126) relative to said first control lever (122) and on the orientation of the engine (100, E) relative to the working machine. 2. The control assembly as claimed in claim 1, further comprising a control panel (112) to be mounted on the engine (100, E), said first and second control levers (122, 126) being coaxially mounted about a common axis on said control panel (112) for rotation relative thereto. 3. The control assembly as claimed in claim 2, wherein said means for causing said first control lever (122) to rotate with said second control lever (126) in said direction of increasing engine speed comprises a return spring (124) mounted about said common axis and urging said first control lever (124) in said direction of increasing engine speed. 4. The control assembly as claimed in claim 3, wherein, upon rotation of said second control lever (126) by said inner cable (2) of said Bowden wire (1) about said common axis in a direction opposite said direction of increasing engine speed, said first or second engaging section (126a, 126b) of said second control lever (126) contacts said abutment member (122c) of said first control lever (122) and rotates said first control lever (122) in said opposite direction against the force of said return spring (124). 5. The control assembly as claimed in claim 2, wherein said outer cable mounting means comprises a control panel cover (130) mountable on said control panel (112) in a plurality of orientations, said cover (130) having first and second opposite sides, each side having therein two outer cable clamping means (130e, 130f; 130g, 130h). 6. The control assembly as claimed in claim 5, wherein said control panel cover (130) has therein a pair of slots (130a, 130b), said second control lever (126) extending through a selected one of said slots (130a, 130b), said selected slot (130a; 130b) limiting the range of rotation of said second control lever (126) in opposite directions about said common axis. 7. The control assembly as claimed in claim 6, wherein said pair of slots (130a, 130b) are phase-shifted by 180° relative to each other about said common axis. 8. The control assembly as claimed in claim 1, further comprising a governor spring (153) connected to said first control lever (122) and to be connected to the throttle valve.

Inventors: KAZUYUKI, KOBAYASHI NAGOYA MACH. WORKS
Applicants: MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1988
Main classification: F02D11
IPC codes: F02D11, F02M1