Abstract:
The invention relates to a self-lubricating chain which includes a connecting pin which is used to connect inner and outer link portions. The connecting pin includes a lubricating hole and a hollow portion where a lubricating oil supply may be disposed and held in place by a lid member, which provides a press fit and tight seal so as to provide a reliable lubricating oil supply and a durable chain which has improved durability.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The entire disclosure of Japanese Patent Application No. 2008-256505, filed Oct. 1, 2008 is expressly incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. The Field of the Invention 
         [0003]    The present invention relates to a self lubricating chain which may be used as a roller chain, a bush chain, a bushless roller chain or a chain where the roller is fitted directly onto a roller pin without using a bush. More particularly, the present invention relates to a self-lubricating chain which may be used as a bucket chain for loading iron core, coal, and the like, as a chain for conveying heavy loads, such as automobiles, and the like, or as a flow conveyor chain for conveying granules. 
         [0004]    2. The Relevant Technology 
         [0005]    In one self-lubricating chain currently known in the art, an outer link and inner link are connected together in a large number according to the specific requirements of the chain. The outer link includes at least two outer link plates which are connected to the inner links using front and rear connecting pin holes into which a connecting pin is fitted. The inner link includes at least two inner link plates which are connected together using front and rear bushes, which may be fit-secured bushes or loosely fitted bushes. In this chain, a lubricating hole is formed in the center of the connecting pin in the longitudinal direction. A hollow portion is formed on one side of the connecting pin and is used for attaching a lubricating oil supply device to the hollow portion so that lubricating oil is supplied from the lubricating hole to the outer circumferential of the connecting pin. 
         [0006]    An example of one such connecting pin  510  currently known in the art is shown in  FIG. 7 . The connecting pin  510  includes a lubricating hole  511  formed at the substantially central portion in a longitudinal direction of the connecting pin which opens at an outer circumferential surface  510   a , so that a lubricating oil can be supplied to the outer circumferential surface  510   a  of a connecting pin through the lubricating hole  511 . 
         [0007]    The connecting pin  510  also includes a hollow portion  512 , which extends from one side of the connecting pin  510  to an end portion  513  which is located at the center of the connecting pin in the longitudinal direction. The bottom portion  513  includes a concave fitting portion  514  having a lubricating oil inflow port  514   a  which communicates with the lubricating hole  511 . 
         [0008]    A lubricating oil supply device  520  is detachably mounted to the hollow portion  512 . The oil supply device  520  has a length substantially equal to the length of the hollow portion  512 . At a front end of the lubricating oil supply device  520  is formed a protruding portion  521  having a lubricating oil outflow port  521   a . When the lubricating oil supply device  520  is attached to the hollow portion  512 , the protruding portion  521  is screwed in the concave fitting portion  514  so as to be brought into close contact therewith, and the lubricating oil outflow port  521   a  of the protruding portion  521  and the lubricating oil inflow port  514   a  of the concave fitting portion  514  are connected to each other so that a lubricating oil reservoir  522  and the lubricating hole  511  communicate with each other. 
         [0009]    An outflow mechanism, which allows a lubricating oil to gradually flow out of the lubricating oil outflow port  521   a  is formed at the substantially central portion in a longitudinal direction of the connecting pin, and a lubricating oil within lubricating oil reservoir  522  is supplied to the outer circumferential surface  510   a  of the connecting pin. This continues until the lubricating oil within the lubricating oil reservoir  522  is depleted, at which time the supply of the lubricating oil is performed by exchanging the lubricating oil supply device  520 . 
         [0010]    An example of one such chain currently known in the art is described in Japanese Patent Publication No. 2007-246234. 
         [0011]    One problem with this configuration, however, is that the lubricating oil supply device  520  is screwed into the hollow portion  512 . Thus, at the time of attaching or detaching of the lubricating oil supply device  520 , it is necessary to turn the entire lubricating oil supply device  520 . Unfortunately, this process is time consuming, and it is necessary to spend a large amount of time to replace the oil supply device  520 . 
         [0012]    Further, since the lubricating oil supply device  520  is loosely fitted into the hollow portion  512 , a space is formed between the lubricating oil supply device  520  and the hollow portion  512 , meaning that foreign matter can enter from the outside. Additionally, as the self-lubricating chain is driven, vibrations form in the space, generating noise or loosening the screw between the protruding portion  521  and the concave fitting portion  514 . In some instances, these problems can lead to leaks and the deterioration of the chain. 
         [0013]    Also, because one end of the lubricating oil supply device  520  is exposed, it is possible that the oil supply device  520  may become damaged or broken as articles are conveyed by the chain. 
         [0014]    Accordingly, there is a need for a self-lubricating chain which solves the above-mentioned prior art problems by allowing the quick and easy replacement of the lubricating oil supply device, wherein the chain and oil supply device prevent the entry of foreign matter, reduce the vibration of the lubricating oil supply device due, reduce noise, and prevent leakage and deterioration of the chain. 
         [0015]    The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced 
       BRIEF SUMMARY OF THE INVENTION 
       [0016]    These and other limitations are overcome by embodiments of the invention which relate to a new design for an engagement chain, which has improved buckling strength and durability. 
         [0017]    This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
         [0018]    A first embodiment of the invention is a self-lubricating chain. The chain includes an outer link including at least two outer link plates including front and rear connecting pin holes, the two outer link plates each being securely fit on ends of connecting pins disposed in the front and rear connecting pin holes, an inner link including at least two inner link plates, the two inner link plates being fit together using bushes disposed therebetween, the inner link and outer link being connected by the connecting pins connecting to the bushes, and a lubricating oil supply device having a protruding portion having a lubricating oil outflow port. The connecting pin includes a lubricating hole is formed in the center portion of the connecting pin in the longitudinal direction so as to connect the inside of the connecting pin to the outside of the connecting pin, a hollow portion formed inside the connecting pin, which has a concave fitting portion which extends from one side of the connecting pin to the central portion of the connecting pin so as to communicate with the lubricating hole. The lubricating oil supply device is attachably and detachably attached in a close fitted and press-sealed manner to concave fitting portion of the hollow portion using a lid member so that lubricating oil is supplied from said lubricating hole to the outside of the connecting pin. 
         [0019]    One benefit of aspects of the invention is that because the hollow portion has a concave fitting portion communicating with the lubricating hole at the bottom portion, and a protruding portion of the lubricating oil supply device having a lubricating oil outflow port which is closely fitted to the concave fitting portion, with the lubricating oil supply device being press-sealed into the hollow portion using a lid member, it is possible to quickly and easily attach and detach the lubricating oil supply device without rotating the oil supply device. Thus, it is easier to attach and detach the lubricating oil supply device of the present invention. Furthermore, it is possible to prevent damage to the lubricating oil supply device because the oil supply device is not exposed to the articles conveyed by the chain and the like. 
         [0020]    Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
           [0022]      FIG. 1  is partial cross-sectional and plan view of a self-lubricating chain according to a first embodiment of the present invention; 
           [0023]      FIG. 2  is a side view of the self-lubricating chain of  FIG. 1 ; 
           [0024]      FIG. 3  is an A-A cross-sectional view of  FIG. 1 ; 
           [0025]      FIG. 4  is a front view of  FIG. 3 ; 
           [0026]      FIG. 5  is an enlarged view of portion B of  FIG. 3 ; 
           [0027]      FIG. 6  is an enlarged view of portion C of  FIG. 3 ; and 
           [0028]      FIG. 7  is a cross-sectional view of a connecting pin in a self-lubricating chain currently known in the art. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    Embodiments of the invention relate to a self-lubricating chain, which is an example of the present invention, will be described with reference to drawings below. 
         [0030]      FIGS. 1 and 2  illustrate a self-lubricating chain  100  according to one embodiment of the invention. The chain  100  includes an outer link including outer link plates  101  each of which include front and rear connecting pin holes  103  which are fit-secured using a connecting pin  110  to an inner link. The inner link includes a pair of inner link plates  102  which include front and rear bush holes  104  which are connected by a roller  105  and loosely fitted bushes  106 . The inner links and outer links are connected to each other in a large number by alternately connecting loosely fitting connecting pins  110  to the bushes  106 . 
         [0031]    As shown in  FIGS. 1 and 3  in the central portion of the connecting pin  110  in the longitudinal direction is formed a lubricating hole  111 , which opens from the inside of the connecting pin  110  to an outer circumferential surface  110   a . A hollow portion  112  having a bottom portion  113  is formed so as to extend from one end of the connecting pin  110  to the center of the connecting pin  110  in the longitudinal direction. The hollow portion  112  is attachably and detachably attached a lubricating oil supply device  120 . Lubricating oil is supplied to the outer circumferential surface  110   a  of the connecting pin through the lubricating hole  111 . Further, the connecting pin  110  and the bush  106  connected to as to enable the smooth rotation therebetween. 
         [0032]    As shown  FIGS. 3-6 , the hollow portion  112  of the connecting pin  110  has a concave fitting portion  114  communicating with the lubricating hole  111  at the bottom portion  113 . A lid receiving concave portion  115 , which has a large diameter, is provided on one side the connecting pin  110 , and is connected to the hollow portion  112 . 
         [0033]    The lubricating oil supply device  120  has a protruding portion  121  having a lubricating oil outflow port. The lubricating oil supply device  120  is inserted to a concave fitting portion  114  provided at the bottom portion  113  of the hollow portion  112  of the connecting pin  110 . The lubricating oil supply device  120  is brought into close fit-contact with the bottom  113  by placing a bottom portion O-ring  123  between the lubricating oil supply device  120  and the connecting pin  110 . 
         [0034]    A female thread portion is provided on an inner circumference of the lid receiving portion  115 . A lid member  130  having a male thread portion is screwed into female thread portion on the outer circumference of the lubricating oil supply device  120 . The lubricating oil supply device  120  is closely press-sealed into the hollow portion  112  of the connecting pin  110  through an O-ring  124  at the opening and pressing O-ring  125 . 
         [0035]    The lid member  130  is provided with an engagement hole  131 , which engages with a tool at the time of screwing. When the lubricating oil supply device  120  is screwed to a position where it is closely press-sealed into the hollow portion  112  of the connecting pin  110 , the lid member  130  is formed such that it is received in the lid receiving concave portion  115  of the connecting pin  110 . 
         [0036]    Using the above-mentioned configuration, lubricating oil supplied from the lubricating oil supply device  120  is supplied to the outer circumferential surface  110   a  of the connecting pin through the lubricating hole  111  without leaking out to the hollow portion  112  because of the O-ring  123  which is positioned when the lubricating oil supply device  120  is secured to the connecting pin  110 . By using the O-ring  123  at the bottom portion, the O-ring  124  at the opening portion and the pressing O-ring  125  between the lubricating oil supply device  120  and the connecting pin  110 , it is possible to securely position the lubricating oil supply device  120  without allowing leaks and without transmitting vibration to the lubricating oil supply device  120 . Thus it is possible to reduce leaks, noise, unwanted debris, and vibration without loosening the fitting between the protruding portion  121  and the concave fitting portion  114 . As the result the durability and life of the chain can be extended. 
         [0037]    Further, the lid member  130  can be used to press the lubricating oil supply device  120  into the hollow portion  112  of the connecting pin  110 , the attaching and detaching of the lubricating oil supply device  120  can be easily reliably performed, and at the same time since an end surface of the lubricating oil supply device  120  is not exposed at an end surface of the connecting pin  110 , it is possible to prevent damage to the lubricating oil supply device  120  due to a direct clash with articles being conveyed by the chain. 
         [0038]    While the lubricating oil supplied to an outer circumferential surface  110   a  of the connecting pin  110  acts together with a lubricant in order to reduce rotational sliding friction between the connecting pin  110  and the bush  106 , a useless outflow of the lubricating oil to the outside is prevented by a seal structure provided on both end portions in the axial direction of the bush  106 . 
         [0039]    As shown in  FIG. 3 , the seal structure is composed of a distance member  140  disposed between the outer link plate  101  and the inner link plate  102  and an oil seal  150  provided between the inner link plate  102  and the distance member  140 . The distance member  140  has a flat shape on an outer link plate  101  side and is fitted to an outer circumference of the connecting pin  110  integrally with the outer link plate  101  with a step portion  141  is provided on an inner link plate  102  side. The outer circumferential side than the step portion  141  faces the inner link plate  102  with very small space being formed between the step portion  141  and the inner link plate  102 . 
         [0040]    Both ends of the bush  106  are fitted into bush holes  104  of the inner link plate  102  so that they protrude to extend within the area of the step portion  141  of the distance member  140  and an oil seal  150  is provided in a space between an inner circumference of the step portion  141  of the distance member  140  and the inner link plate so that two lips  151  of the oil seal  150  come into sliding contact with the distance member  140 . 
         [0041]    Since the distance member  140  is machined the surface of the distance member  140  has a smooth surface which optimal for providing a sealing function. 
         [0042]    Using the above-mentioned configuration, the lubricating oil supplied from the lubricating oil supply device  120 , which lubricates rotational sliding of the connecting pin  110  and the bush  106 , is sealed by bringing the lip of the oil seal  150  into sliding contact with the distance member  140  which has a smooth surface using a pressing force. Thus, the amount of outflow is controlled by the discharge of the self-lubricating device and the entry of foreign matter from the outside can be prevented. 
         [0043]    Further, the space between two lips  151  of the oil seal  150  functions as a lubricating oil reservoir, and the life of the oil seal is increased. Because the discharge route for lubricating oil includes a very small space between the distance member  140  and the inner link plate  102 , the very small space between the distance member  140  and the oil seal  150  and the very small space between the distance member  140  and the inner link plate  102 , the discharge route has a labyrinth structure, making it more difficult for foreign matter to enter from the outside, while ensuring that the lubricating oil is stably supplied to an outer circumferential surface of the connecting pin. 
         [0044]    Since the distance member  140  is composed of an independent member other than an outer link plate  101  and an inner link plate  102  which are selected for a required tensile strength, a material specialized for sliding or seal performance can be selected as a material of the distance member  140 . Furthermore, there is no need to modify the shape of the outer link plate  101  and inner link plate  102 , meaning that it is possible to easily manufacture the self-lubricating oil supply device. 
         [0045]    As described above, according to the present invention, the attaching and detaching of the lubricating oil supply device is a simple and reliable process which can be performed so as to reduce the vibration, noise, and debris that exist in the chains currently known in the art. Further, lubricating oil is reliably supplied to an outer circumferential surface of the connecting pin so that the life of the chain can be extended. Thus the effects of the present invention are very large. 
         [0046]    The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 
         [0047]    Although embodiments of the invention may comprise any type of the chains such as a roller chain, a bush chain, a bushless chain and the like. Thus, the present invention may be utilized in any chain in which lubrication is needed on a circumferential surface of a connecting pin. 
         [0048]    Further, although the self-lubricating chain of the present invention may be used in any variety of situations, the embodiments described herein are particularly useful in a largely loaded chain such as a bucket chain for loading iron core, coal and the like, a large load chain for conveying heavy articles such as automobiles and the like, a flow conveyer chain and the like for granules or the like.