The right of foreign priority is claimed under 35 U.S.C. § 119(a) based on Federal Republic of Germany Application No. 10 2007 020 681.1, filed May 3, 2007, the entire contents of which, including the specification, drawings, claims and abstract, are incorporated herein by reference.
The invention relates to an internal combustion engine of the generic type specified in the preamble of claim 1, and to a cable retainer for securing at least one cable to an internal combustion engine.
An internal combustion engine which has a cylinder and cooling ribs is known, for example, from U.S. Pat. No. 6,289,856 B1. Such internal combustion engines are used, for example, in hand-held tools such as power saws, cut-off grinders, clearing saws or the like, in order to drive the tool.
The ignition of the internal combustion engine is provided in known internal combustion engines by means of a sparkplug which is connected to an ignition module via an ignition cable. It is also possible to provide other cables, for example for controlling or for grounding.
In order to permit simple handling of hand-held tools it is desirable for the housing in which the internal combustion engine is arranged to be kept as small as possible. However, at the same time it is necessary to avoid damage to the cables.
In known internal combustion engines, cables of the ignition module are laid loosely. The cables are merely secured to one another by means of cable binders. As a result, the position of the cables relative to the internal combustion engine and also relative to a housing, for example the housing of a tool, is not fixed. The cables can move relative to the internal combustion engine during operation. Therefore, sufficient installation space must be made available for the cables to ensure that the cables cannot come to bear on adjacent components owing to their movement during operation since this could lead to wear.
The invention is based on the object of providing an internal combustion engine of the generic type which permits an internal combustion engine to be installed in a comparatively small housing. A further object of the invention is to provide a cable retainer for an internal combustion engine.
This object is achieved by means of an internal combustion engine having the features of claim 1. In terms of the cable retainer, the object is achieved by means of a cable retainer having the features of claim 18.
The cable retainer fixes the position of the at least one cable relative to the internal combustion engine. As a result, the cable can be routed right against the internal combustion engine. Owing to the defined position of the cable, cable wear can be avoided. As a result, the internal combustion engine can be installed even under constricted installation conditions.
The cable retainer is advantageously arranged on the cylinder of the internal combustion engine. The cable retainer advantageously has means for positioning the cable retainer on the internal combustion engine. This makes it possible to ensure that the cable retainer is placed in a defined position, which cannot be confused, on the internal combustion engine. The cable retainer is easily secured to the internal combustion engine if the cable retainer has at least one slot with which the cable retainer is plugged onto a cooling fin. The slot can have play here, in particular with respect to the cooling fin, in order to compensate tolerances of the internal combustion engine. The cable retainer advantageously has a first slot which receives a first cooling fin which is positioned, in particular, transversely with respect to the cylinder longitudinal axis. In particular, the cable retainer has a second slot which receives a second cooling fin which extends transversely with respect to the first cooling fin. The first slot advantageously extends approximately parallel to the cylinder longitudinal axis. Through the slot, the cable retainer is respectively secured in a perpendicular direction with respect to the corresponding cooling fin. As a result, the position of the cable retainer on the internal combustion engine is fixed even if the cable retainer can execute slight movements with respect to the internal combustion engine owing to tolerances and owing to play. These movements can be allowed since they do not affect the securing of the position of the cables with respect to the internal combustion engine.
The cable retainer advantageously has a receptacle in which at least one cable is retained. The receptacle is bounded, in particular, by at least two limbs, wherein at least one of the limbs is sprung. The sprung embodiment of at least one limb allows the cable to be pressed between the limbs and therefore easily mounted in the receptacle. The sprung embodiment of the limbs permits, in particular, clamping of the cable so that the cable cannot move in the receptacle, either in its longitudinal direction or transversely with respect to the receptacle. It is also possible, for example, to provide three or more limbs which are arranged, in particular, offset in the longitudinal direction of the cable and alternately on each side of the cable.
In order to permit simple mounting of the cable in the cable retainer even under restricted spatial conditions, there is provision for the receptacle to be accessible via a longitudinal opening which is bounded by at least two limbs, wherein at least one limb has, adjacent to the longitudinal opening, an insertion slope which extends inclined with respect to the longitudinal direction of the cable. Owing to the inclined arrangement of the insertion slope, the cable can be arranged on the receptacle in an oblique position with respect to the longitudinal direction of the receptacle and can be mounted from an oblique orientation in the receptacle. The oblique mounting permits the cable to be arranged in the receptacle even if only very small spring travel values of the limbs are possible, for example owing to the comparatively small possible overall size of the cable retainer.
In order to permit the largest possible spring travel of the limbs there is provision that a slot extends adjacent to the bottom area of the receptacle, wherein the side walls of the slot are inclined with respect to one another by an angle which opens toward the internal combustion engine. As a result, the entire side wall of the slot can be moved together with the limb which is arranged thereon. As a result, the possible spring travel can be made larger without adversely affecting the stability of the cable retainer.
There is provision for at least one cable to be held clamped in the receptacle. The receptacle advantageously has a lower section and an upper section between which a constriction is arranged, wherein a cable which closes off the lower section of the receptacle is held clamped in the upper section. In particular, at least one cable which is retained in the receptacle by the cable in the upper section is arranged in the lower section. The diameter of the cable in the lower section is advantageously smaller than the diameter of the cable in the upper section. As a result, the position can easily be secured, the position of a plurality of cables being advantageously secured at the same time.
In order to define on which cooling fins the cable retainer will be mounted there is provision for the cable retainer to have a stop which is adjacent to a third cooling fin, with the third cooling fin being made lower than at least one adjacent cooling fin. Owing to the stop it is not possible to arrange the cable retainer next to a cooling fin which is made higher than the third cooling fin. In this context, the stop does not have to bear against the third cooling fin. The height at which the stop extends is between the height of the third cooling fin and the height of the adjacent, relatively high cooling fin. As a result, the position of the cable retainer on the internal combustion engine is fixed. Incorrect mounting is avoided.
Means for securing the cable retainer to the internal combustion engine are advantageously provided. The securing means secure the cable retainer which is plugged onto the internal combustion engine. The internal combustion engine advantageously has an ignition module, and the cable retainer is arranged adjacent to the ignition module, wherein at least one cable which is retained by the cable retainer is connected to the ignition module. This makes it possible to ensure that the cables which are made to lead away from the ignition module are led past the internal combustion engine in a defined fashion. The ignition module is advantageously fixed to at least one screw boss of the internal combustion engine via an insulating element. The insulating element advantageously insulates the ignition module thermally from the internal combustion engine. The insulating element expediently secures the cable retainer to the internal combustion engine. The insulating element must, in any case, be fixed to the internal combustion engine. Since the insulating element is used to secure the cable retainer, no additional components are required. No additional mounting steps are necessary. As a result, the cable retainer is secured to the internal combustion engine in a simple and reliable way.
A simple configuration is obtained if the cable retainer has a bearing web, wherein the cable retainer is plugged onto the internal combustion engine in an insertion direction, and wherein the insulating element secures the bearing web in the insertion direction of the cable retainer. As a result, the cable retainer is secured counter to the insertion direction in a simple way and without additional components.
In order to fix the direction in which the cables are routed, there is provision for the insulating element to have at least one stop for the connection of a cable which is retained in the cable retainer.
For a cable retainer for securing at least one cable to an internal combustion engine there is provision for the cable retainer to have at least one receptacle for at least one cable, and at least one means for positioning the cable retainer on the internal combustion engine. As a result, the cable retainer can easily ensure the relative position of the cable with respect to the internal combustion engine.
The cable retainer advantageously has a first slot and a second slot for plugging the cable retainer onto at least one cooling fin of the internal combustion engine. As a result, the cable retainer can easily be arranged on the internal combustion engine. The slots secure the position of the cable retainer relative to the internal combustion engine. At the same time, the slots can have play with respect to the cooling fins of the internal combustion engine in order to compensate tolerances, for example fabrication tolerances of the internal combustion engine. The slots advantageously extend transversely, and in particular approximately perpendicularly, with respect to one another, in a plane which extends perpendicularly with respect to the insertion direction. As a result the slots fix the position of the cable retainer in two directions which are transverse, in particular perpendicular, with respect to one another.
There is provision for a slot to extend adjacent to the bottom area of the receptacle, wherein the side walls of the slot are inclined with respect to one another in the insertion direction by an angle, wherein the angle opens toward the plug-in opening of the slot. The receptacle is advantageously bounded by two limbs, wherein at least one of the limbs is embodied in a sprung fashion.
In order to make the cable retainer easy to manufacture and low in weight there is provision for the cable retainer to be composed of plastic. The cable retainer is advantageously made of polyamide. As a result, sufficient heat resistance of the cable retainer is provided. The cable retainer is expediently embodied in one piece.
Further objects, features and advantages of the present invention will become apparent from the detailed description of preferred embodiments that follows, when considered together with the accompanying Figures of drawing.
An exemplary embodiment of the invention is explained in the text which follows with reference to the drawing, in which:
The internal combustion engine 8 is connected to a carburetor 7 which is controlled by the throttle lever 4. An air filter 6 is secured to the carburetor 7. The internal combustion engine 8 sucks in fuel and combustion air via the air filter 6 and the carburetor 7 during operation. An exhaust gas silencer 11 is arranged at the outlet of the cylinder 9. The power saw 1 has a guide rail 12 which guides a saw chain 13. The saw chain 13 is driven by the internal combustion engine 8 so that it runs around the guide rail 12. To do this, the internal combustion engine 8 has a crankshaft 40 which is driven in rotation around a crankshaft axis 14.
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An ignition cable 18 is provided for supplying power to the sparkplug 16, said ignition cable 18 connecting the ignition module 19 to a sparkplug connector 17. The sparkplug connector 17 is removeably plugged onto the sparkplug 16 and it supplies the sparkplug 16 with ignition energy. As is shown in particular by
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The profile of the insertion slopes 49 and 50 can be seen in particular in
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In order to permit the cable retainer 30 to be plugged on, the first slot 38 has the plug-in opening 65 which is shown in
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The foregoing description of preferred embodiments of the invention has been presented for purposes of illustration and description only. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible and/or would be apparent in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and that the claims encompass all embodiments of the invention, including the disclosed embodiments and their equivalents.
Number | Date | Country | Kind |
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10 2007 020 681.1 | May 2007 | DE | national |