Fuel tanks, blow molding tools and handheld machine tools

Abstract

The invention relates to an oil tank having a filling nozzle (24) and a closure cap (22) for closing the filling nozzle. A sealing surface or end surface (54) provided for sealing is provided between the filling nozzle and the closure cap to form a labyrinth seal structure (52), which is designed to at least allow air to enter the oil tank and to prevent oil from flowing out of the oil tank, and is formed by an at least partially circumferential groove (58) in a circumferential sealing surface or end surface of the closure cap and / or the filling nozzle and / or in a sealing ring (26) between the closure cap and the oil tank, the sealing ring being constructed as a separate sealing element and being designed so that the sealing element is at least used to reinforce the radial and / or axial contact surface of the sealing element relative to the filling nozzle by a force or compression applied to the sealing element when the closure cap is closed. The invention proposes a blow molding tool for manufacturing an oil tank. The invention also relates to a handheld machine tool having an oil tank.

Description

[0001] This application is a divisional application of the invention application with application number 201910542634.2, application date June 21, 2019, and invention name “Oil tank, blow molding tool and handheld machine tool”. Technical Field

[0002] The present invention relates to an oil tank and a blow molding tool for producing the oil tank. In addition, the present invention also relates to a handheld machine tool having the oil tank. Background Art

[0003] Conventional oil tanks for chain saws usually have a filling opening with a closure cap. Separately therefrom, a low-pressure valve is usually provided on the oil tank to balance the pressure in the oil tank when the liquid level drops and to allow additional inflow of air from outside the oil tank into the inside of the oil tank.

[0004] WO 14 082 664 A1 discloses an oil tank for a chain saw in which a plurality of axial grooves are provided on the filler neck in order to enable pressure compensation when the oil tank is opened or closed. Summary of the invention

[0005] The present invention is based on a fuel tank, wherein the fuel tank has a filling nozzle and a closure cap for closing the filling nozzle, wherein a sealing surface or end surface provided for sealing forms a labyrinth seal structure between the filling nozzle and the closure cap, the labyrinth seal structure being constructed to at least allow air to enter the fuel tank and to prevent oil from flowing out of the fuel tank, wherein the labyrinth seal structure is formed by an at least partially circumferential groove in a circumferential sealing surface or end surface of the closure cap and / or the filling nozzle and / or in a sealing ring between the closure cap and the fuel tank, wherein the sealing ring is constructed as a separate sealing element and is designed so that the sealing element is at least used to reinforce the radial and / or axial contact surface of the sealing element relative to the filling nozzle by a force or compression applied to the sealing element when the closure cap is closed. According to the present invention, the labyrinth seal structure is at least used to allow air to enter the fuel tank and to prevent oil from flowing out of the fuel tank. This function can be realized in the closed state of the closure cap, that is, when the closure cap closes the filling nozzle. Furthermore, the function is ensured during operation, during storage and / or during transport. That is, at least during normal use, no oil can escape. The closure cap can be screwed to the filler neck of the oil tank by means of a thread, but other connection methods are also conceivable, for example by means of form-locking or force-locking elements, for example by means of clamping elements, clamping means or the like. In an advantageous manner, an additional ventilation valve on the oil tank or, alternatively, a valve integrated into the closure cap can also be omitted. Since no separate components are required, this increases reliability and reduces costs.

[0006] In addition, it is proposed that the labyrinth seal structure is composed of an at least partially encircling groove in the encircling sealing surface or end face of the closure cover and / or the oil tank and / or the filling nozzle and / or in the sealing ring between the closure cover and the oil tank. The sealing surface or end face can be arranged in particular on the flange of the corresponding element. The sealing surface or end face is arranged to contact, in particular squeeze the sealing surface or end face of the filling nozzle and / or the sealing part in the closed state. The "closed state" should be understood as a state that is completely screwed into the oil tank or the filling nozzle (also see the definition above). The groove is constructed in an arc shape, in particular a circular arc shape. The labyrinth is realized by the encircling groove. The groove prevents viscous oil from flowing completely through the groove, while gaseous air can pass through the groove. The air flow volume / speed can be influenced by selecting the geometry of the groove.

[0007] Furthermore, it is proposed that the groove has an opening at one end radially toward the outside of the surrounding end surface and at the other end radially toward the inside of the surrounding end surface. Thus, the groove is open to the inside and outside of the tank when the filler neck is closed. As already mentioned, a separate valve on the tank can thus be omitted in a simple manner.

[0008] In addition, it is proposed that the groove is around>180°, especially around>270°, preferably around>320° in the surrounding sealing surface or end face. The filling nozzle, the sealing part and the closing cap are advantageously round. A force lock on the sealing surface or end face is generated between the filling nozzle and the closing cap in the form of: the corresponding thread is screwed on the filling nozzle and the closing cap. Through the surrounding groove, especially when the filling nozzle or the closing cap is horizontally arranged on the hand-held machine tool or the housing of the hand-held machine tool, the oil is difficult to flow out in the following way: the oil must rise in the channel or the groove against the gravity. "Horizontal arrangement" should be understood as an arrangement in which the center axis of the filling nozzle or the spiral direction axis of the closing cap is not vertically relative to the basic support surface of the hand-held machine tool, but extends essentially horizontally. The basic support surface should be understood as the surface on which the hand-held machine tool is usually placed or used during operation. Horizontal here means parallel to the ground surface.

[0009] The groove can have, for example, a depth of 1 mm and a width of 0.6 mm. This prevents the oil from escaping from the handheld power tool, but allows air to flow in and enables the oil tank to be emptied without back pressure. Thus, at least as long as the other components involved in the oil delivery are functioning normally, the oil delivery pump does not create a vacuum in the oil tank that could prevent the oil delivery to the pump.

[0010] It is further proposed that the closure cap or the injection nozzle has a multi-thread, in particular a double-thread. Thus, overloading of the injection nozzle can be avoided. The greater the lift, the smaller the tightening force proportional to the torque. In addition, the force is distributed over multiple spirals. The sealing surface is more evenly loaded with force. In addition, the distance that the air must cross when the pressure is balanced is shorter (not along a long spiral in the circumferential direction). The closing time or the rotation angle for completely closing the closure cap is reduced because the multi-thread generally has a greater lift. The closure cap can be screwed directly onto or into the injection nozzle at multiple points or in multiple angular positions.

[0011] The present invention proposes that the spiral of the multi-thread on the closure cap or the injection nozzle extends in the circumferential direction at an angle less than 360° divided by the number of spirals, and in particular, in the case of a double-thread, extends in the circumferential direction at an angle less than 180°. Thus, even when the closure cap is screwed in (because a certain gap is left radially between the threads of the closure cap and the injection nozzle), an axial direct connection parallel to the spiral axis is formed between the spirals. Pressure balance can be performed with less resistance. However, in addition, when observed in the circumferential direction, a gap or free surface is also formed between the spirals. Advantageously, there is no high tolerance requirement for the free surface. On the contrary, the thread on the injection nozzle or the closure cap has a much smaller tolerance. Therefore, for example, during the manufacturing process, the tool can accurately fix the oil tank on the free surface. Advantageously, the gap area contains a separating seam or a parting surface of a tool or a blow molding tool. The manufacturing process, especially the blow molding process, can be simplified by the low quality requirements for the free surface without spirals. Finishing is eliminated and costs are saved.

[0012] The present invention proposes that the filling nozzle has a multi-thread internal thread and the closing cap has a multi-thread external thread. As a result, the end face of the closing cap can be pressed against the seal or sealing surface on the filling nozzle on the flange of the closing cap. However, the seal can also seal the housing of the handheld power tool radially relative to the filling nozzle. Therefore, even when oil overflows, for example, when oil is poured into the oil tank, oil will not enter the housing of the handheld power tool. The oil will not flow into the gap or slit between the oil tank and the housing of the handheld power tool, but will either flow into the oil tank or flow externally onto the housing of the handheld power tool. There, the oil can be easily absorbed, for example, with a rag.

[0013] The present invention provides a blow molding tool for manufacturing a fuel tank, wherein the fuel tank has an internal thread on a filling nozzle, wherein the blow molding tool has the same number of parting surfaces as the number of spirals of the internal thread of the fuel tank to be manufactured, and the spiral negative mold for manufacturing the filling nozzle on the blow molding tool extends in the circumferential direction at an angle less than 360° divided by the number of spirals.

[0014] Furthermore, the present invention claims protection for a process for blow molding a fuel tank having an internal thread on a filler neck, the process comprising at least the following steps: in particular depending on the multi-linearity of the internal thread to be manufactured, a tool fixes the filler neck on the inner circumference of the filler neck between the spiral threads, in particular at least at locations spaced apart from each other by an angle of 360° divided by the multi-linearity of the thread.

[0015] Furthermore, the present invention claims a portable power tool having the above-mentioned oil tank.

[0016] Furthermore, the present invention claims protection for a handheld power tool, in particular the handheld power tool described above, which has a handheld power tool housing, a fuel tank with a filler neck and a closing cover for closing the fuel tank, wherein the sealing ring is provided both for sealing the fuel tank and for sealing a separating gap between the handheld power tool housing and the fuel tank.

[0017] Furthermore, the handheld power tool has a sealing ring between the handheld power tool housing and the oil tank, in particular, the sealing ring is simultaneously a sealing ring between the oil tank and the closure cap. The sealing ring thus radially seals between the handheld power tool housing and the oil tank or its filler neck and prevents oil from entering the handheld power tool housing. Furthermore, however, the sealing ring also seals the oil tank with respect to the outflow of oil to the outside of the oil tank if the closure cap is screwed on. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further advantages are obtained from the following description of the drawings. The drawings, the description and the claims contain a combination of many features. A person skilled in the art can also consider these features individually and combine them into other meaningful combinations.

[0019] The accompanying drawings show:

[0020] Figure 1 A part of a hand-held power tool in the form of a chain saw or a chain saw housing;

[0021] Figure 2 A cross-sectional view of a portion of a chain saw or a chain saw housing having an oil tank;

[0022] Figure 3 a perspective view of the closure cover;

[0023] Figure 4 according to Figure 3 A top view of a closure cover;

[0024] Figure 5 A portion of a fuel tank having a filling connection;

[0025] Figure 6 An alternative chainsaw. DETAILED DESCRIPTION

[0026] Figure 1 A section of a handheld power tool in the form of a chain saw 10 or a chain saw housing 11 is shown. The blade and the saw chain are concealed. The handheld power tool has a first and a second handle 12, 14, by means of which the handheld power tool can be gripped or guided. A motor (not shown) which is usually arranged in the chain saw housing 11 can be activated by at least one switch 16. In order to supply lubricating oil to the saw chain (not shown), the handheld power tool has an oil tank 18, of which only a filler level indicator 20 can be seen here. A closure cap 22 closes a filler neck 24 (not shown here) of the oil tank 18 (see FIG. 2 ). Figure 2 The closure cap 22 or the filling connection 24 is arranged horizontally (laterally) on the chain saw housing 11. That is, the opening or the filling connection 24 points in the lateral direction. In principle, however, the filling connection 24 can also be oriented vertically, in particular in the upper region of the chain saw 10 (see Figure 6 ). The extent of the level indicator 20 arranged essentially vertically on the chain saw housing indicates that the level of the oil tank 18 can be above at least a lower region or a middle region of the closure cap 22 or of the subsequent filling connection 24 (assuming that the level indicator indicates the level from empty to full over its extent). In principle, the present invention is of course also applicable to other handheld power tools, in particular those with continuous oil lubrication of the cutting element or cutting beam. In such handheld power tools, the liquid level usually drops during operation, so that a vacuum is formed in the oil tank, so that if the oil is to be conveyed further with little resistance, additional air must be introduced.

[0027] Figure 2 Shown in a substantially horizontal section (through the closure cap 22) Figure 1 1 and 1 . A sectional view of a portion of a chain saw 10 or a chain saw housing 11 is shown. At least the oil tank 18, its filling connection 24, the seal (in particular the sealing ring 26) and the closure cap 22 are cut through. In addition, the closure cap stopper 28, the chain saw housing 11, the filling level indicator 20 and possibly further elements are at least partially cut through. The oil tank 18 (see also Figure 5) has an internal thread 30 in the area of ​​the filling nozzle 24 or the filling opening 36, which has two spirals 32, 34. The lift of the multi-thread thread is greater than that of the single-thread thread. Therefore, the transmission ratio is greater (more axial movement per relative rotation). Under the condition of a limited rotational tightening force, the axial force acting on the spiral is smaller due to the greater lift. Therefore, when tightening the thread, the thread is rarely overloaded, which makes the oil tank 18 or its permanent closure performance achieved by means of the closure cap 22 more secure. The internal thread 30 or the filling nozzle 24 is not easy to deform, and the sealing quality is maintained. The outflow opening is not shown here, but is constructed separately from the filling opening 36, especially at the bottom of the oil tank 18 or near the bottom. The closure cap 22 has an external thread 38. This external thread also has two spirals 40, 42 or is constructed as a multi-thread. The tolerance of the internal thread 30 of the filling nozzle 24 is relatively coarse. However, the tolerance of the "negative mold" of the internal thread 30 on the outside of the filling nozzle is narrow. This is because the semi-finished product or the oil tank 18 is held from the outside by a tool (which always has the same / accurate geometry) during the manufacturing process (here blow molding), but the internal geometry can be slightly different due to the blow molding process. The "negative mold" or cutout 44 of the internal thread 30 and the smooth, round outer side 46 of the filling nozzle 24 are advantageously used to fix and position the oil tank 18 in the chain saw housing 11 or the hand-held power tool. For this purpose, at least one form-locking element, in particular one or more latching projections 48, is provided on the chain saw housing. By means of the smooth and round outer side 46 and the latching projections 48, the oil tank 18 can be positioned and / or fixed on the chain saw housing 11 very accurately. The oil tank can be completely clamped on the chain saw housing 11, which is ensured by the bevel on the latching projections 48. The spacing a in the separating gap 70 between the filling nozzle 24 and the wall 50 of the chain saw housing 11 is thus very accurately defined and can serve as a sealing surface for the sealing element or sealing ring 26. This prevents, for example, oil that escapes between the filling nozzle 24 and the chain saw housing 11 when filling the oil tank 18 from penetrating into the interior of the chain saw housing. This reduces the risk of contamination and avoids possible accidental contamination due to oil that "subsequently / accidentally" escapes from the chain saw housing 11. Customer satisfaction and safety are improved. In contrast, excess or overflowing oil can be easily seen and / or wiped off or absorbed on the outside of the chain saw housing 11 or on the surface of the chain saw 10. In addition, the internal structure of the chain saw 10 is also kept clean, and the reliability of the device is thus increased. However, no additional sealing element is required between the chain saw housing 11 and the filling nozzle 24 to achieve this function, because only a sealing element or a sealing ring 26 is used, which is also used to seal the oil tank 18.

[0028] The selective sealing (air inlet, but oil not outlet) or labyrinth seal 52 of the oil tank 18 or, in other words, the selective sealing between the filling opening 36 or the filling connection 24 and the closure cap 22 is realized as follows:

[0029] Closing cap 22 (see in particular Figure 3 and 4 ) has an end face 54 configured for sealing. The end face is arranged on a flange 56 of the closure cover. A labyrinth seal structure 52 is machined into the end face 54 or into an axial end face (axial with respect to the screw-in direction or tightening direction) or into the flange 56. The labyrinth seal structure 52 allows air to enter the oil tank 18 and is used to prevent oil from flowing out of the oil tank 18. The labyrinth seal structure 52 is formed by an at least partially surrounding groove 58. The groove is machined into the surrounding end face 54 or the flange 56. The groove 58 has an opening 60 radially toward the outside of the surrounding end face 54 or the flange 56 at one end. The groove 58 has an opening 62 radially toward the inside of the surrounding end face 54 or the flange 56 at the other end. Therefore, there is no direct line of sight connection between the outer opening 60 and the inner opening 62. The groove 58 advantageously extends in the circumferential end face 54 or the collar 56 around >180°, in particular around >270°, preferably around >320°. Figure 3, the groove 58 surrounds almost 360°. The groove 58 can also be spirally surrounded in the end face 54 or the flange 56, and realize a smooth transition to the outside and inside of the closure cover 22. However, in the current case, the groove 58 is circular. Between the outer opening 60 and the inner opening 62, the wall of the bearing end face 54 extends almost as much as the dividing strip 64. The depth of the groove 58 (inward toward the end face) is about 1mm. The width of the groove 58 (in the radial direction from the rotation axis of the closure cover 22) is about 0.6mm. The surrounding length or the surrounding angle of the groove 58, the ratio of its depth and width can be changed, especially in relation to the expected viscosity of the filling medium or oil to be filled into the oil tank 18. In particular, air is allowed to enter when the liquid level of the tank drops and / or in order to avoid the formation of a vacuum in the tank. In addition, oil outflow is avoided. The viscosity of the oil prohibits the oil from slowly passing through the labyrinth seal structure 52 or the groove 58. Due to the falling liquid level or the formation of a vacuum during operation, the oil accumulated in the labyrinth seal 52 or the recess 58 is sucked into the oil tank 18. Thus, oil remaining on the end face 54 or in the region of the filling opening 36 (for example when the oil tank 18 is filled) is also sucked into the oil tank 18. The sealing ring 26 is advantageously designed, in particular with a rectangular or square cross section, so that it is used at least to reinforce the sealing of the radial and / or axial contact surface of the sealing ring relative to the chain saw housing 11 or the filling nozzle 24 by the force or pressure exerted on the sealing ring when the closure cover 22 is closed. Thus, the oil tank 18 is sometimes additionally fixed to the chain saw housing 11 by the closure cover 22 and / or advantageously not only forms a seal of the axial end face 54 or the axial contact surface between the closure cover 22 and the filling nozzle 24, but also forms a radial and / or axial seal relative to the filling nozzle 24, the chain saw housing 11 and / or the closure cover 22.

[0030] Figure 5A detail of a tank 18 with a filler neck 24 is shown. The two threads 32, 34 of the internal thread 30 extend less than 180°. A thread gap or a smooth and / or toleranced filler neck wall 66 is opened between them to a certain extent. The thread gap comprises the parting plane of the blow molding tool when manufacturing the tank 18. Due to the bilinearity or multilinearity of the internal thread 30 (which extends in the circumferential direction at a maximum angle of 360° divided by the number of threads), lower tolerance requirements are imposed on the blow molding tool than when the internal thread 30 extends beyond the tool parting plane. This saves costs in the tool or in the manufacturing process. Simple demoulding is possible. However, an axial gap (in the screw-in direction) or a direct connection without thread obstruction is also formed between the threads 32, 34, even when the closure cap 22 is screwed on or screwed in. This makes it possible to achieve a pressure balance between the inside and outside of the tank 18 with little resistance. In principle, the thread 30 can also have a different number of threads 32, 34. Advantageously, the threads also have "gaps" or free or smooth surfaces between the threads in the circumferential direction. This is ensured by the threads extending in the circumferential direction at an angle less than 360° divided by the number of threads.

[0031] In principle, the labyrinth seal 52 can be formed in particular by an at least partially circumferential groove 58 in a circumferential end face, in particular of the flange 56, of the tank 18 and / or of the closure cap 22 and / or in a seal or sealing ring 26 between the tank 18 and the closure cap 22. Thus, the principle can also be applied to filler necks with an external thread or to tanks that do not have a seal between the closure cap and the filler opening or the filler neck, but only have adjacent end faces. By means of a labyrinth arrangement between two adjacent elements, such as the closure cap and the sealing ring and / or the sealing ring and the filler neck or the filler neck and the closure cap, the air flow can be influenced, in particular variably influenced, depending on the closed position or screwed position of the adjacent seals to each other, in particular depending on the screwed position or the closed position.

[0032] Figure 6 An alternative chain saw 10 is shown, which has a closure cover on the upper side of the chain saw 10. Here too, a correspondingly vertically arranged oil tank 18 with a closure cover 22 and a labyrinth seal 52 and / or with a sealing ring 26 can be used, which prevents oil from escaping into the chain saw housing and simultaneously seals the oil tank. In addition, the chain saw 10 also shows a chain 72 which is provided for pivoting on a blade.

Claims

1. An oil tank (18), comprising a filling nozzle (24) and a closing cover (22) for closing the filling nozzle (24), characterized in that: A sealing surface or end surface (54) provided for sealing forms a labyrinth seal (52) between the filler neck (24) and the closure cap (22), the labyrinth seal being designed at least for allowing air to enter the oil tank (18) and for preventing oil from flowing out of the oil tank (18), wherein the filler neck (24) has a multi-turn internal thread and the closure cap (22) has a multi-turn external thread, wherein when the oil tank (18) is closed with the closure cap (22), the end surface (54) of the closure cap (22) presses against a seal (26) on the filler neck (24) at a flange (56) of the closure cap, wherein the seal (26) is provided for also radially sealing a housing (11) of a hand-held power tool (10) relative to the filler neck (24).

2. The oil tank (18) according to claim 1, characterized in that The labyrinth seal (52) is formed by an at least partially circumferential groove (58) in a circumferential sealing surface or end surface (54) of the closure cap (22) and / or of the filler neck (24) and / or in a seal (26) between the closure cap (22) and the filler neck (24).

3. The oil tank (18) according to claim 2, characterized in that The groove (58) has an opening (60) at one end radially outwardly of the surrounding sealing surface or end surface (54), and has an opening (62) at the other end radially inwardly of the surrounding sealing surface or end surface (54).

4. The oil tank (18) according to claim 2 or 3, characterized in that: The groove (58) has an opening (60) at one end toward the outside of the oil tank (18) and an opening (62) at the other end toward the inside of the oil tank (18).

5. The oil tank (18) according to claim 2 or 3, characterized in that: The groove (58) extends around >180° in the circumferential sealing surface or end face (54).

6. The oil tank (18) according to claim 2 or 3, characterized in that The groove (58) has a depth of 1 mm and a width of 0.6 mm.

7. The oil tank (18) according to claim 1, characterized in that The threads of the multi-turn external thread on the closure cap (22) or the multi-turn internal thread on the filler neck (24) extend in the circumferential direction at an angle that is less than 360° divided by the number of the threads.

8. The oil tank (18) according to claim 5, characterized in that The groove (58) extends around >270° in the circumferential sealing surface or end face (54).

9. The oil tank (18) according to claim 5, characterized in that The groove (58) extends around >320° in the circumferential sealing surface or end face (54).

10. The oil tank (18) according to claim 1, characterized in that The multi-thread internal thread and the multi-thread external thread are configured as double-thread threads.

11. The oil tank (18) according to claim 10, characterized in that The spiral of the double-turn external thread on the closure cap (22) or the double-turn internal thread on the filler neck (24) extends in the circumferential direction by less than 180°.

12. A chain saw (10) comprising an oil tank (18) according to any one of claims 1 to 11.

13. A handheld power tool comprising a handheld power tool housing (11) and an oil tank (18) according to any one of claims 1 to 11, characterized in that: A seal (26) is provided, which serves not only to seal the oil tank (18) but also to seal a separation gap between the hand-held power tool housing (11) and the oil tank (18).

14. The handheld power tool according to claim 13, characterized in that The seal (26) between the hand-held power tool housing (11) and the oil tank (18) is simultaneously a seal (26) between the closure cap (22) and the filler neck (24).

15. The handheld power tool according to claim 13 or 14, characterized in that The hand-held power tool is in the form of a chain saw (10).

16. The handheld power tool according to claim 13 or 14, characterized in that: The seal (26) is provided for radially sealing the hand-held power tool housing (11) relative to the filler neck (24).

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