The present disclosure generally relates to a sleeve holder for a hydraulic cylinder, in particular, sleeve holders for hydraulic cylinders used as a pit prop or a moving cylinder unit in underground mining.
In underground mining, hydraulic cylinders are frequently used as telescopic pit props or moving cylinders in self-advancing supports.
In such hydraulic cylinders, a sleeve holder is commonly screwed into a cylinder tube or, in case of a telescopic pit prop, an outer cylindrical tube and an inner cylindrical tube. The sleeve holder serves to support and guide the inner cylindrical tube and/or the piston rod, and receives and transfers forces from the piston rod to the cylinder tube, or from the piston rod to the inner cylindrical tube and from the inner cylindrical tube to the outer cylindrical tube. In addition, the sleeve holder seals the annular space formed between the corresponding elements. Further, the sleeve holder commonly includes grooves and the like for receiving sealing gaskets for sealing the annular space.
It has been found that, as a consequence of the rough operating conditions underground, the sleeve holder may come loose due to the forces applied to and transferred by the same. Therefore, it is necessary to secure the sleeve holder to the cylinder tube of a cylinder and the outer and/or inner cylindrical tube of a telescopic pit prop. An example for a method of securing a sleeve holder to a hydraulic cylinder is shown in U.S. Pat. No. 6,615,705 B2.
The disclosed systems and methods are directed at least in part to improving known systems.
In one aspect, the present disclosure relates to a hydraulic cylinder. The hydraulic cylinder comprises an outer cylindrical tube including an open end and an outer circumferential groove adjacent to the open end, and a movable element slideably received in the outer cylindrical tube through the open end. A sleeve holder is threadably engaged with the outer cylindrical tube at the open end to seal an annular space formed between the outer cylindrical tube and the movable element. The sleeve holder includes at least one tangential bore aligned with the outer circumferential groove. The hydraulic cylinder further comprises at least one locking pin received in the outer circumferential groove and the at least one tangential bore to secure the sleeve holder to the outer cylindrical tube.
In another aspect, the present disclosure relates to a sleeve holder for a hydraulic cylinder, the hydraulic cylinder including an outer cylindrical tube having an open end and a movable element slideably received in the outer cylindrical tube through the open end. The sleeve holder comprises a male threaded portion configured to threadably engage a female threaded portion formed in the outer cylindrical tube at the open end, and at least one tangential bore formed in the sleeve holder. The at least one tangential bore is configured to be aligned with a circumferential groove formed in the outer cylindrical tube and to receive a locking pin to secure the sleeve holder to the outer cylindrical tube.
According to another aspect, the present disclosure relates to a hydraulic cylinder comprising an outer cylindrical tube including an open end, a first female threaded portion having a first pitch, a second female threaded portion having a second pitch oppositely directed to the first pitch, the second female threaded portion being disposed closer to the open end than the first female threaded portion, and a movable element slideably received in the outer cylindrical tube through the open end. A sleeve holder is threadably engaged with the first female threaded portion to seal an annular space formed between the outer cylindrical tube and the movable element. The sleeve holder includes a first male threaded portion mating with the first female threaded portion. A locking ring is threadably engaged with the second female threaded portion to secure the sleeve holder to the outer cylindrical tube. The locking ring includes a second male threaded portion mating with the second female threaded portion.
In a further aspect, the present disclosure relates to a sleeve holder assembly for a hydraulic cylinder, the hydraulic cylinder including an outer cylindrical tube having an open end and a movable element slideably received in the outer cylindrical tube through the open end. The sleeve holder assembly comprises a sleeve holder configured to threadably engage a first female threaded portion formed in the outer cylindrical tube. The sleeve holder includes a first male threaded portion having a first pitch. The sleeve holder assembly further comprises a locking ring configured to threadably engage a second female threaded portion formed in the outer cylindrical tube to secure the sleeve holder to the outer cylindrical tube. The locking ring includes a second male threaded portion having a second pitch oppositely directed to the first pitch.
According to another aspect, the present disclosure relates to hydraulic cylinder comprising an outer cylindrical tube including an open end and a female threaded portion at the open end, and a movable element slideably received in the outer cylindrical tube through the open end. A sleeve holder is threadably engaged with the female threaded portion to seal an annular space formed between the outer cylindrical tube and the movable element. The sleeve holder includes a male threaded portion mating with the female threaded portion and a tapered outer surface extending toward the open end of the outer cylindrical tube to create a wedge-shaped annular space between the sleeve holder and the outer cylindrical tube that widens toward the open end. A tapered locking ring is inserted into the wedge-shaped annular space and attached to the outer cylindrical tube to secure the sleeve holder to the outer cylindrical tube. The tapered locking ring includes a tapered inner surface mating with the tapered outer surface of the sleeve holder.
In a further aspect, the present disclosure relates to a sleeve holder assembly for a hydraulic cylinder, the hydraulic cylinder including an outer cylindrical tube having an open end and a movable element slideably received in the outer cylindrical tube through the open end. The sleeve holder assembly comprises a sleeve holder configured to threadably engage a female threaded portion in the outer cylindrical tube. The sleeve holder includes a male threaded portion formed at a first end of the sleeve holder in an axial direction and a tapered outer surface spaced apart from the male threaded portion and extending toward an opposite second end of the sleeve holder in the axial direction. The sleeve holder assembly further comprises a tapered locking ring including a tapered inner surface mating with the tapered outer surface of the sleeve holder and a plurality of attachment portions for receiving a plurality of fastening elements to attach the tapered locking ring to the open end of the outer cylindrical tube, to thereby secure the sleeve holder to the outer cylindrical tube.
Other features and aspects of the present disclosure will be apparent from the following description and the accompanying drawings.
The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described herein are intended to teach the principles of the present disclosure, enabling those of ordinary skill in the art to implement and use the present disclosure in many different environments and for many different applications. Therefore, the exemplary embodiments are not intended to be, and should not be considered as a limiting description of the scope of protection. Rather, the scope of protection shall be defined by the appended claims.
The present disclosure may be based in part on the realization that, in case fastening elements such as screws or brackets are used to secure the sleeve holder to the hydraulic cylinder, the loads applied to the sleeve holder may become so large that the screws or the welds used to attach the brackets may break. Further, the provision of fastening elements such as heavy-type dowel pins or of self-locking threads on the sleeve holder may complicate the assembly of the sleeve holder. In accordance with the exemplary sleeve holders described below, the present disclosure provides sleeve holders which are easy to install and, at the same time, durable.
Referring now to the drawings,
Outer cylindrical tube 12 includes an open end 13 at one end of the same in an axial direction. Further, outer cylindrical tube 12 includes an outer circumferential groove 24 (see
Inner cylindrical tube 14 is configured similar to outer cylindrical tube 12 and includes an open end 36 and a circumferential groove 35 (see
First sleeve holder 16 is screwed into outer cylindrical tube 12 at open end 13 to seal annular space 18 and to support and guide inner cylindrical tube 14. Sleeve holder 16 includes a male threaded portion 20 configured to threadably engage a female threaded portion 22 formed in an inner surface of outer cylindrical tube 12 at open end 13, an engagement portion 26 (see
Seconds sleeve holder 40 is configured substantially similar to first sleeve holder 16, with a male threaded portion 42 configured to threadably engage a female threaded portion 38 formed in inner cylindrical tube 14 at open end 36, an engagement portion 44 (see
Securing of sleeve holder 16 to outer cylindrical tube 12 (and of sleeves holder 40 to inner cylindrical tube 14) will be described in the following with reference to
As shown in
Further, a tangential bore 28 is formed in sleeve holder 16, namely, extending from an outer surface of sleeve holder 16 tangentially to an inner surface of groove 45 facing outer cylindrical tube 12. In particular, tangential bore 28 is formed such that it is aligned with circumferential groove 24 when sleeve holder 16 has been screwed into outer cylindrical tube 12. In the example shown in
After sleeve holder 16 has been screwed into outer cylindrical tube 12 and tangential bore 28 has been aligned with circumferential groove 24, a locking pin 30 is inserted into tangential bore 28 and circumferential groove 24 to secure sleeve holder 16 to outer cylindrical tube 12. In particular, locking pin 30 may prevent movement of sleeve holder 16 in the axial direction, preventing sleeve holder 16 from becoming loose when forces are applied to the same during operation of hydraulic cylinder 10.
As shown in
As shown in
With the above-described configuration, sleeve holders 16, 40 can be easily and reliably secured to cylindrical tubes 12, 14.
As shown in
As shown in
As shown in
Locking ring 56, which is formed as a bushing with a counter-rotating thread, includes a second male threaded portion 62 having a second pitch oppositely directed to the first pitch, i.e., a left-hand (counterclockwise) thread or a right-hand (clockwise) thread. Second male threaded portion 62 is configured to engage with a second female threaded portion 64 formed in outer cylindrical tube 52 with a corresponding pitch that is oppositely directed to the pitch of first female threaded portion 60.
After sleeve holder 54 has been screwed into outer cylindrical tube 52, locking ring 56 is threaded into outer cylindrical tube 52 in the opposite direction, until it abuts against an upper surface of flange 61 of sleeve holder 54, to thereby secure sleeve holder 54 to outer cylindrical tube 52. In this manner, if sleeve holder 54 comes loose during operation of hydraulic cylinder 50, rotating in a direction in which sleeve holder 54 is unscrewed from outer cylindrical tube 52, the opposite pitch of second male threaded portion 62 formed on locking ring 56 will result in tightening of sleeve holder 54 against locking ring 56, thereby securing the same.
In order to assure that locking ring 56 does not come loose during operation of hydraulic cylinder 50, additional fastening elements (not shown) may be provided to positively or non-positively secure locking ring 56 to outer cylindrical tube 52. It should be noted, however, that these fastening elements do not have to bear the large loads acting on sleeve holder 54 during operation of hydraulic cylinder 50.
Referring now to
As shown in
As shown in
Sleeve holder 84 is configured to threadably engage female threaded portion 92 and includes a male threaded portion 98 formed at a first end of sleeve holder 84 in an axial direction and mating with female threaded portion 92. Sleeve holder 84 further includes a tapered outer surface 91 spaced from male threaded portion 98 in the axial direction and extending toward an opposite second end of sleeve holder 84 in the axial direction to create a wedge-shaped space 95 between sleeve holder 84 and outer cylindrical tube 82 (see
As shown in
As shown in
Further, to allow disassembly of tapered locking ring 86 and sleeve holder 84, tapered locking ring 86 includes a plurality of threaded bores 90 distributed in the circumferential direction at positions different from the positions of attachment portions 93. When tapered locking ring 86 and sleeve holder 84 are to be disassembled, a plurality of screws are threaded into threaded bores 90 to push tapered locking ring 86 away from outer cylindrical tube 82. In this manner, tapered locking ring 86 and sleeve holder 84 may be removed from outer cylindrical tube 82.
With the above configuration, sleeve holder 84 may be easily and durably attached to outer cylindrical tube 82. Further, sleeve holder 84 may also be easily removed from outer cylindrical tube 82 if necessary.
While the previous examples have been described in connection with hydraulic cylinders configured as telescopic pit props including both an outer cylindrical tube and an inner cylindrical tube, it should be appreciated that the same sleeve holders can be used in case of a hydraulic cylinder including only an outer cylinder tube and a piston rod received in the same. In such configurations, the corresponding sleeve holder is secured to the outer cylinder tube and supports and guides movement of the piston rod in the cylinder tube.
The industrial applicability of the systems and methods disclosed herein will be readily appreciated from the foregoing discussion. One exemplary application of the sleeve holders disclosed herein are telescopic pit props or moving cylinder units used in underground mining. However, it should be appreciated that the configurations disclosed herein can also be applied to hydraulic cylinders in general, whether they are telescopic or not.
In accordance with some embodiments, a method of securing a sleeve holder to a hydraulic cylinder comprises providing a hydraulic cylinder comprising an outer cylindrical tube including an open end and an outer circumferential groove adjacent to the open end. The method further comprises arranging a movable element in the outer cylindrical tube to be slideably received in the same through the open end. A sleeve holder is threadably engaged with the outer cylindrical tube at the open end to seal an annular space formed between the outer cylindrical tube and the movable element. The sleeve holder includes at least one tangential bore. The method further comprises aligning the at least one tangential bore with the outer circumferential groove formed in the outer cylindrical tube, and inserting at least one locking pin into the outer circumferential groove and the at least one tangential bore to secure the sleeve holder to the outer cylindrical tube.
In accordance with other embodiments, a method of securing a sleeve holder to a hydraulic cylinder comprises providing an outer cylindrical tube including an open end, a first female threaded portion having a first pitch, and a second female threaded portion having a second pitch oppositely directed to the first pitch, the second female threaded portion being disposed closer to the open end than the first female threaded portion. The method further comprises inserting a movable element into the outer cylindrical tube to be slideably received in the same through the open end. A sleeve holder is threadably engaged with the first female threaded portion to seal an annular space formed between the outer cylindrical tube and the movable element. The sleeve holder includes a first male threaded portion mating with the first female threaded portion. The method further comprises threadably engaging a locking ring with the second female threaded portion to secure the sleeve holder to the outer cylindrical tube, the locking ring including a second male threaded portion mating with the second female threaded portion.
In accordance with other embodiments, a method of securing a sleeve holder to a hydraulic cylinder comprises providing an outer cylindrical tube including an open end and a female threaded portion at the open end. The method further comprises inserting a movable element to be slideably received in the outer cylindrical tube through the open end. A sleeve holder is threadably engaged with the female threaded portion to seal an annular space formed between the outer cylindrical tube and the movable element. The sleeve holder includes a male threaded portion mating with the female threaded portion and a tapered outer surface extending toward the open end to create a wedge-shaped space between the sleeve holder and the outer cylindrical tube. The method further comprises inserting a tapered locking ring into the wedge-shaped space and attaching the same to the outer cylindrical tube to secure the sleeve holder to the outer cylindrical tube. The tapered locking ring includes a tapered inner surface mating with the tapered outer surface of the sleeve holder.
It will be appreciated that the foregoing description provides examples of the disclosed systems and methods. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of disclosure more generally. All methods described herein may perform in any suitable order unless otherwise indicated herein or clearly contradicted by context.
Accordingly, this disclosure includes all modifications and equivalences of the subject-matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or clearly contradicted by context.
Although the preferred embodiments of this disclosure have been described herein, improvements and modifications may be incorporated without departing from the scope of the following claims.
Number | Date | Country | Kind |
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20 2014 002 977.6 | Apr 2014 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2015/000664 | 3/27/2015 | WO | 00 |