A tiltrotator for an excavator

Abstract

A tiltrotator for an excavator, the tiltrotator comprising a worm gear 2 and a housing (3 fig. 1) for the worm gear. The worm gear has a main gear wheel 4 and a worm screw 5. The housing further compr

Description

[0002] The invention relates to a tiltrotator for an excavator. In particular, the invention relates to a tiltrotator with a worm gear and a housing for the worm gear, the worm gear comprising a main gearwheel and a worm screw which is engaged with the main gear wheel such that rotation of the worm screw results in rotation of the main gear wheel. Background

[0003] Tiltrotators for excavators provide two planes of rotational movement to equipment attached to the end of the jib arm of an excavator. Tiltrotators can also be used on other earthmoving or material handling equipment and are not limited for use in excavators. One of the planes of movement is controlled by two externally mounted hydraulic cylinders mounted about central load bearing shaft. The other is controlled by a hydraulic motor and gear assembly to create the rotational movement. The hydraulic motor may be internal or externally mounted with a shaft prodtruding into the main casing.

[0004] In the tiltrotator the main gearwheel is operated by a hydraulically operated worm screw. During the manufacturing process there can be some clearance due to manufacturing tolerances and over time the meshing faces between the gear wheel and the worm screw can wear and an excessive amount of clearance can present. This clearance can allow for excessive uncontrolled movement and in some cases shock loading which could shear gear teeth and cause an accident as well as damaging the equipment beyond repair. In other systems excess clearance is dealt with by means of dismantling and removing the worm screw and motor and inserting a series of different sized shims to move the worm screw or gear wheel, or both. This results in significant maintenance time involving disassembly most of the tiltrotator.

[0005] The present invention seeks to obviate or mitigate the problem requiring full disassembly of a tiltrotator in order to adjust the position of the worm screw in the tiltrotator. Summary of the Invention

[0006] According to a first aspect of the invention there is provided a tiltrotator for an excavator, the tiltrotator comprising: a worm gear and a housing for the worm gear, the worm gear comprising a main gear wheel and a worm screw which is engaged with the main gear wheel such that rotation of the worm screw results in rotation of the main gearwheel, the housing further comprising a worm screw shaft having a longitudinal axis, the worm screw being disposed in the worm screw shaft, the housing further comprising an opening to the worm screw shaft, the tiltrotator further comprising a worm screw shaft end cap disposed in the worm screw shaft between the worm screw and the opening to the worm screw shaft, wherein the worm screw shaft end cap is movable relative to the worm screw shaft, and wherein the worm screw shaft end cap in the worm screw shaft is movable along the longitudinal axis of the worm screw shaft by rotating the worm screw shaft end cap.

[0007] Prior art tiltrotators typically have a worm screw shaft end cap end cap that is bolted to the housing. To adjust the position of the worm screw in the worm screw shaft, the entire worm screw shaft and worm screw shaft end cap is removed to allow the installation of shims in the worm screw shaft. The worm screw shaft end cap is then bolted back into position. The presence of the shim now urges the worm screw further into the worm screw shaft for operation. The operator can use different size shims to adjust the position of the worm screw in the worm screw shaft as required.

[0008] These prior art systems typically have eight bolts that fix the worm screw shaft end cap to the housing. Thus, to make the adjustment, the operator is required to remove and replace and torque eight bolts. Further, there is no possibility for fine adjustment of the worm screw position. The operator must decide on a shim size and complete the reassembly process, then test the machine. If there is still problems, complete disassembly and reassembly is required, using a different sized shim. The problem is eliminated by a trial and error process as it is not possible to determine the effect of a particular shim until the tiltrotator is fully assembled.

[0009] The present invention overcomes these problems by using a worm screw shaft end cap that can move along the worm screw shaft, rather than having a fixed position only. The operator can make fine adjustments by rotating the worm screw shaft end cap, causing it to move along axis of the worm screw, causing the worm screw to move. There is no requirement to remove the worm screw shaft end cap and insert a shim to adjust the position of the worm screw shaft. The adjustment process is therefore greatly simplified relative to the prior art, and it allows for finer adjustments than the prior art, as it is not limited to insertion of specific sizes of shims.

[0010] Optionally, wherein the movement of the worm screw shaft end cap in one direction or in at least one direction along the longitudinal axis of the worm screw shaft results in movement of the worm screw in the worm screw shaft.

[0011] Optionally, the worm screw shaft end cap is movable along the longitudinal axis of the worm screw shaft by rotating the worm screw shaft end cap about the longitudinal axis of the worm screw shaft.

[0012] Optionally, the worm screw shaft end cap is movable along the longitudinal axis of the worm screw shaft by rotating the worm screw shaft end cap clockwise or anticlockwise about the longitudinal axis of the worm screw shaft.

[0013] Optionally, the worm screw shaft end cap can be moved along the longitudinal axis of the worm screw shaft in increments of less than 1 mm.

[0014] Optionally, the worm screw shaft end cap can be moved along the longitudinal axis of the worm screw shaft in increments of less than 0.75 mm.

[0015] Optionally, the worm screw shaft end cap can be moved along the longitudinal axis of the worm screw shaft in increments of less than 0.5 mm.

[0016] Optionally, the worm screw shaft end cap can be moved along the longitudinal axis of the worm screw shaft in increments of less than 0.3 mm.

[0017] Optionally, the tiltrotator further comprises a locking means to prevent movement of the worm screw shaft end cap in the worm screw shaft. This prevents movement of the worm screw shaft end cap and therefore potential movement of the worm screw after adjustment of the worm screw position.

[0018] Optionally, the locking means is removable or can be deactivated to release the worm screw shaft end cap and enable relative movement between the worm screw shaft end cap and the worm screw shaft.

[0019] Optionally, the locking means is a locking member. Optionally, the locking member is a plate.

[0020] Optionally, the locking means is engageable with both the worm screw shaft end cap and the housing.

[0021] Optionally, the locking means may be fixed to both the worm screw shaft end cap and the housing to prevent relative movement between the worm screw shaft end cap and the worm screw shaft.

[0022] Optionally, when the locking means is engaged with the worm screw shaft end cap, the worm screw shaft end cap and the locking means are prevented from rotating relative to one another.

[0023] Optionally, the worm screw shaft end cap has an engagement member for engaging with the locking means. Alternatively or additionally, the locking means may have an engagement member for engaging with the worm screw shaft end cap.

[0024] Optionally, the locking means comprises an aperture for receiving the engagement member of the worm screw shaft end cap. The aperture may extend entirely through or partially through the locking means. Alternatively or additionally, the worm screw shaft end cap may comprise an aperture for receiving the engagement member of the locking means. The aperture may extend entirely through or partially through the locking means.

[0025] Optionally, when the engagement member of the worm screw shaft end cap is disposed in the aperture of the locking means, relative rotational movement between the locking means and the work screw shaft end cap is prevented. Optionally, when the engagement member of the locking means is disposed in the aperture of the worm screw shaft end cap, relative rotational movement between the locking means and the work screw shaft end cap is prevented.

[0026] Optionally, there is a mechanical interlock formed between locking means and the worm screw shaft end cap when the engagement member is inserted into the aperture.

[0027] Optionally, when the locking means is engaged with the housing, the locking means is prevented from rotating relative to the housing.

[0028] Optionally, the locking means is engageable with the housing by fixing means that fix the locking means to the housing.

[0029] Optionally, the fixing means are removable from the locking means and the housing.

[0030] Optionally, the tiltrotator of any preceding claim further comprising a cover for the opening.

[0031] Optionally, the locking means provides the cover for the opening.

[0032] Optionally, the worm screw shaft end cap is in direct or indirect abutment with the worm screw.

[0033] Optionally, the tiltrotator further comprises a spacer disposed between the worm screw and the worm screw shaft end cap.

[0034] Optionally, the spacer is fixed and does not rotate when the worm screw rotates.

[0035] Optionally, the tiltrotator further comprises at least one washer disposed over the worm screw.

[0036] According to a second aspect of the invention there is provided a method of adjusting a worm screw in the tiltrotator according to the first aspect of the invention, the method comprising rotating the worm screw shaft end cap. Optionally, the method involves adjusting the position of the worm screw in the worm screw shaft.

[0037] Optionally, the method comprises initially removing the locking means.

[0038] Optionally, the method comprises replacing the locking means after rotating the worm screw shaft end cap and adjusting the worm screw. List of Figures

[0039] Specific implementations of the present disclosure will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0040] Figure 1 shows a perspective exploded view of a tiltrotator according to the invention.

[0041] Figure 2 shows a cross-sectional view of the tiltrotator of Figure 1. Detailed Description

[0042] In the figures there is shown a tiltrotator for an excavator. The tiltrotator is indicated generally by reference numeral 1. The tiltrotator has a worm gear 2 and a housing 3 for the worm gear 2. The worm gear 2 has a main gear wheel 4 and a worm screw 5. The worm screw 5 is engaged with the main gear wheel 4 such that rotation of the worm screw 5 results in rotation of the main gearwheel 4. The housing 3 further has a worm screw shaft 6. The worm screw shaft 6 has a longitudinal axis 9. The worm screw 5 is disposed in the worm screw shaft 6.

[0043] The housing 3 further has an opening 7 to the worm screw shaft 6. The tiltrotator 1 further has a worm screw shaft end cap 8 disposed in the worm screw shaft 6 between the worm screw 5 and the opening 7 to the worm screw shaft 6. The worm screw shaft end cap 8 is movable relative to the worm screw shaft 6. Movement of the worm screw shaft end cap 8 along the longitudinal axis of the worm screw shaft results in movement of the worm screw 5 in the worm screw shaft 6. The worm screw shaft end cap 8 in the worm screw shaft 6 is movable along the longitudinal axis 9 of the worm screw shaft 6 by rotating the worm screw shaft end cap 8.

[0044] The worm screw shaft end cap 8 is movable along the longitudinal axis 9 of the worm screw shaft 6 by rotating the worm screw shaft end cap 8 about the longitudinal axis 9 of the worm screw shaft 6. More specifically, the worm screw shaft end cap 8 is movable along the longitudinal axis 9 of the worm screw shaft 6 by rotating the worm screw shaft end cap 8 clockwise or anticlockwise about the longitudinal axis 9 of the worm screw shaft 6. In the illustrated embodiment, clockwise rotation of the worm screw shaft end cap 8 results in the worm screw shaft end cap 8 moving towards the worm screw 5. Whereas anticlockwise rotation results in the worm screw shaft end cap 8 moving away from the worm screw 5. In alternative embodiments, the tiltrotator could be configured such that anticlockwise rotation of the worm screw shaft end cap results in the worm screw shaft end cap moving towards the worm screw and clockwise rotation results in the worm screw shaft end cap moving away from the worm screw.

[0045] The worm screw shaft 6 has an internal thread 10. The worm screw shaft end cap 8 has an external thread 11. The external thread 11 of the worm screw shaft end cap 8 mates with the internal thread 10 of the worm screw shaft 6. This enables movement of the worm screw shaft end cap 8 through the worm screw shaft 6 via rotation of the worm screw shaft end cap 8. The worm screw shaft end cap 8 can be moved along the longitudinal axis 9 of the worm screw shaft 6 in increments of less than 0.3 mm.

[0046] The tiltrotator 1 further has a locking means 12 to prevent movement of the worm screw shaft end cap 8 in the worm screw shaft 6. This prevents movement of the worm screw shaft end cap 8 and therefore potential movement of the worm screw 5 after adjustment of the worm screw position. The locking means 12 is removable to release the worm screw shaft end cap 8 and enable relative movement between the worm screw shaft end cap 8 and the worm screw shaft 6. In the illustrated embodiment, the locking means 12 is a plate.

[0047] The locking means 12 is engageable with both the worm screw shaft end cap 8 and the housing 3. The locking means 12 may be fixed to both the worm screw shaft end cap 8 and the housing 3 to prevent relative movement between the worm screw shaft end cap 8 and the worm screw shaft 6. When the locking means 12 is engaged with the worm screw shaft end cap 8, the worm screw shaft end cap 8 and the locking means 12 are prevented from rotating relative to one another.

[0048] The worm screw shaft end cap 8 has an engagement member 13 for engaging with the locking means 12. Alternatively, the locking means may have an engagement member 13 for engaging with the worm screw shaft end cap 8. The locking means 12 comprises an aperture 14 for receiving the engagement member 13 of the worm screw shaft end cap 8. The aperture extends entirely through the locking means 12. In other embodiments, the aperture may only extend partially through the locking means. In other embodiments not shown, the locking means may comprise an engagement member for engaging with the worm screw shaft end cap, and the worm screw shaft end cap may have an aperture to receive the engagement member of the locking means. The aperture may extend wholly or partially through the worm screw shaft end cap.

[0049] When the engagement member 13 of the worm screw shaft end cap 8 is disposed in the aperture 14 of the locking means 12, relative rotational movement between the locking means 12 and the work screw shaft end cap 8 is prevented. In an alternative embodiment, when the engagement member of the locking means is disposed in the aperture of the worm screw shaft end cap, relative rotational movement between the locking means and the work screw shaft end cap is prevented.

[0050] There is a mechanical interlock formed between locking means 12 and the worm screw shaft end cap 8 when the engagement member 13 is inserted into the aperture 14. In the illustrated embodiment, the engagement member 13 has a hexagonal form and the aperture has a serrated perimeter to engage with the corners of the hexagonal form of the engagement member 13. Any suitable form of engagement member and shape of aperture perimeter may be used, provided a mechanical interlock is formed.

[0051] When the locking means 14 is engaged with the housing 3, the locking means 14 is prevented from rotating relative to the housing 3. The locking means is engageable with the housing 3 by fixing means that fix the locking means to the housing. The fixing means are removable from the locking means 14 and the housing 3. The fixing means may be bolts or other suitable fixing means. In the illustrated embodiment, the locking means 14 comprises two apertures 15a, 15b to receive the fixing means. The number of apertures may be one, or greater than two in alternative embodiments. The housing 3 has two corresponding apertures for the fixing means.

[0052] The housing 3 further has a recess 16 for receiving the locking means 12. The recess 16 has a similar shape to that of the locking means 12. When the locking means 12 is set in the recess 16, it is prevented from rotating about the longitudinal axis of the worm screw shaft 6.

[0053] The locking means 12 further provides a cover for the opening 7. In other embodiments, a separate cover over than the locking means may be provided.

[0054] In the illustrated embodiment, the worm screw shaft end cap 8 is in indirect abutment with the worm screw 5. In alternative embodiments, the worm screw 5 may be in indirect abutment with the worm screw 5.

[0055] In the illustrated embodiment, the tiltrotator 1 further comprises a spacer 17 disposed between the worm screw 5 and the worm screw shaft end cap 8. The spacer 17 is fixed and does not rotate when the worm screw 5 rotates.

[0056] The tiltrotator comprises two thrust washers 18 disposed over the worm screw 5.

[0057] In use, the position of the worm screw 5 in the worm screw shaft 6 is adjusted by removing the locking means 12. This can be done by first removing the fixing means, and removing the locking means 12 from the housing 3. Next the operator can rotate the worm screw shaft end cap 8. A tool may be used to assist in rotation of the worm screw shaft end cap 8. The tool may engage with the worm screw shaft end cap engagement member 13. Once the operator has adjusted the worm screw position as desired, the locking member 12 can be replaced and the fixing members can be replaced to secure the locking member 12 to the housing 3, and to prevent further rotational movement of the worm screw shaft end cap 8.

[0058] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently described subject matter pertains.

[0059] Where a range of values is provided, for example, concentration ranges, percentage ranges, or ratio ranges, it is understood that each intervening value, to the tenth of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the described subject matter. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and such embodiments are also encompassed within the described subject matter, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the described subject matter.

[0060] It should be understood that the terms "a" and "an" as used above and elsewhere herein refer to "one or more" of the enumerated components. It will be clear to one of ordinary skill in the art that the use of the singular includes the plural unless specifically stated otherwise. Therefore, the terms “a,” “an” and “at least one” are used interchangeably in this application.

[0061] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as size, weight, reaction conditions and so forth used in the specification and claims are to the understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present subject matter. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0062] Throughout the application, descriptions of various embodiments use "comprising" language; however, it will be understood by one of skill in the art, that in some instances, an embodiment can alternatively be described using the language "consisting essentially of’ or "consisting of'. 26 07 24

Claims

1. A tiltrotator for an excavator, the tiltrotator comprising:a worm gear and a housing for the worm gear,5 the worm gear comprising a main gear wheel and a worm screw whichis engaged with the main gear wheel such that rotation of the worm screw results in rotation of the main gearwheel,the housing further comprising a worm screw shaft having a longitudinal axis, the worm screw being disposed in the worm screw shaft,10 the housing further comprising an opening to the worm screw shaft,the tiltrotator further comprising a worm screw shaft end cap disposed in the worm screw shaft between the worm screw and the opening to the worm screw shaft,wherein the worm screw shaft end cap is movable relative to the worm15 screw shaft, and wherein the worm screw shaft end cap in the worm screwshaft is movable along the longitudinal axis of the worm screw shaft by rotating the worm screw shaft end cap, andwherein the movement of the worm screw shaft end cap in at least one direction along the longitudinal axis of the worm screw shaft results in20 movement of the worm screw in the worm screw shaft.

2. The tiltrotator of claim 1 wherein the worm screw shaft end cap is movable along the longitudinal axis of the worm screw shaft by rotating the worm screw shaft end cap about the longitudinal axis of the worm screw shaft.

3. The tiltrotator of claim 2 wherein the worm screw shaft end cap is movable25 along the longitudinal axis of the worm screw shaft by rotating the worm screwshaft end cap clockwise or anticlockwise about the longitudinal axis of the worm screw shaft.

4. The tiltrotator of any preceding claim further comprising a locking means to prevent movement of the worm screw shaft end cap in the worm screw shaft.26 07 245. The tiltrotator of claim 4 wherein the locking means is removable or can be deactivated to release the worm screw shaft end cap and enable relative movement between the worm screw shaft end cap and the worm screw shaft.

6. The tiltrotator of claim 4 or claim 5 wherein the locking means is engageable 5 with both the worm screw shaft end cap and the housing.

7. The tiltrotator of claim 6 wherein the locking means may be fixed to both the worm screw shaft end cap and the housing to prevent relative movement between the worm screw shaft end cap and the worm screw shaft.

8. The tiltrotator of claim 6 or claim 7 wherein when the locking means is engaged 10 with the worm screw shaft end cap, the worm screw shaft end cap and thelocking means are prevented from rotating relative to one another.

9. The tiltrotator of claim 8 wherein the worm screw shaft end cap has an engagement member for engaging with the locking means.

10. The tiltrotator of claim 9 wherein the locking means comprises an aperture for 15 receiving the engagement member of the worm screw shaft end cap.

11. The tiltrotator of claim 10 wherein when the engagement member is disposed in the aperture of the locking means, relative rotational movement between the locking means and the work screw shaft end cap is prevented.

12. The tiltrotator of any of claims 6 to 8 wherein when the locking means is20 engaged with the housing, the locking means is prevented from rotatingrelative to the housing.

13. The tiltrotator of claim 12 wherein the locking means is engageable with the housing by fixing means that fix the locking means to the housing.

14. The tiltrotator of claim 13 wherein the fixing means are removable from the 25 locking means and the housing.

15. The tiltrotator of any preceding claim further comprising a cover for the opening.26 07 2416. The tiltrotator of claim 15 when dependent on claim 4 wherein the locking means provides the cover for the opening.

17. The tiltrotator of any preceding claim wherein the worm screw shaft end cap is in direct or indirect abutment with the worm screw.5 18. The tiltrotator of any preceding claim further comprising a spacer disposedbetween the worm screw and the worm screw shaft end cap.

19. The tiltrotator of claim 18 wherein the spacer is fixed and does not rotate when the worm screw rotates.

20. The tiltrotator of any preceding claim further comprising at least one washer 10 disposed over the worm screw.

21. A method of adjusting a worm screw in the tiltrotator of any preceding claim, the method comprising rotating the worm screw shaft end cap.

22. The method of claim 21 comprising initially removing the locking means.

23. The method of claim 21 or 22 comprising replacing the locking means after 15 rotating the worm screw shaft end cap and adjusting the worm screw.

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