Patent Publication Number: US-2020283964-A1

Title: Handheld tool for installing or removing railway track fasteners

Description:
TECHNICAL FIELD 
     The present invention relates broadly to a handheld tool for installing or removing a railway track fastener including resilient fasteners such as an E-clip. 
     BACKGROUND OF INVENTION 
     Railway track is usually fixed to the underlying supporting sleeper made of timber, concrete or steel using a variety of fasteners including traditional heavy gauge coach screws into timber sleepers, or resilient clips of various designs inserted under load into sleeper fittings or collars on both sides of each track. Railway track fastening technology often relies on the use of basic hand tools for both the installation and removal of the resilient clips. Removal of clips may involve the use of a rivet punch and sledge hammer to impact the clip in order to dislodge and remove it. Often use of these basic hand tools result in occupational health and safety risks where for example resilient clips become dangerous projectiles when freed suddenly. Improvisation in the removal or installation process, using heavy tools such as sledge hammers, also results in the possibility for operator injury. 
     Recently, the emergence of specialised pneumatic or hydraulic equipment from a variety of international manufacturers has improved the safety, efficiency, and ease of clip insertion and removal. These machines are typically used by one or perhaps two operators, and usually consist of a chassis mounted and rolling on the track rail(s), and a workhead attached to the chassis and incorporating an insertion/removal mechanism. However, machines currently in the marketplace have at least the following shortcomings:
         i) they are relatively heavy and require lifting equipment to transport to site and then locate on the railway track;   ii) they rely upon heavy hydraulic drive systems together with their associated and relatively large power packs, such as diesel-fuelled electrical generators.       

     SUMMARY OF INVENTION 
     According to a first aspect of the present invention there is provided a handheld tool for installing or removing a railway track fastener, said handheld tool comprising: 
     a drive assembly including an actuator sub-assembly mounted for actuation within an actuator housing, the drive assembly also including a jaw member mounted to the actuator housing and adapted to contact either a rail seat or the track fastener; 
     a driven assembly including an actuated sub-assembly operatively coupled to the actuator sub-assembly for longitudinal movement of the driven assembly relative to the drive assembly on actuation of the actuator sub-assembly, the driven assembly also including i) an actuated housing within which the actuated sub-assembly is housed, and ii) an opposing jaw member mounted to the actuated housing and adapted to contact either the track fastener or the rail seat whereby in operation the longitudinal movement of the driven relative to the drive assemblies effects closing of the opposing jaw members relative to one another for installing or removing the track fastener. 
     Preferably the actuator sub-assembly includes an actuator shaft which actuates by rotation within the actuator housing. More preferably the actuated sub-assembly includes i) a threaded coupling arranged to be engaged by the rotating actuator shaft, ii) an adaptor sleeve mounted within the actuated housing and secured to the threaded coupling. Even more preferably the threaded coupling is in the form of an internally threaded nut arranged to be engaged by a corresponding external thread in the actuator shaft. 
     Preferably the external thread of the actuator shaft has a profile shape wherein rotation of the actuator shaft effects axial movement of the threaded coupling which is not back-driveable with respect to the actuator shaft. More preferably the actuator shaft includes an external thread of a trapezoidal, square or buttress profile. 
     Preferably the actuator housing includes an inner sleeve arranged, on the longitudinal movement of the driven relative to the drive assemblies, to reciprocate within an outer sleeve of the actuated housing. More preferably the outer sleeve is mounted coaxial with the adaptor sleeve. Even more preferably the actuator shaft is mounted coaxial with the inner sleeve and is aligned coaxially with the outer sleeve. Still more preferably the actuated sub-assembly also includes a coaxial bearing mounted to the threaded coupling and configured to slide within the inner sleeve. 
     Preferably the actuated sub-assembly includes one or more keys fixed to the adaptor sleeve and arranged to slide for the longitudinal movement of the driven relative to the drive assemblies within corresponding keyways included in the inner sleeve of the actuator housing. More preferably the keys and the corresponding keyways are in transverse section shaped substantially complementary to one another to prevent rotation of the actuated sub-assembly relative to the inner sleeve whilst there is longitudinal movement of the driven relative to the drive assemblies. 
     Preferably the actuated housing includes one or more axially separated coaxial bushes mounted internally of the outer sleeve, the inner sleeve designed to slide within the coaxial bushes. More preferably an outer journaled surface of the inner sleeve is hardened where the coaxial bushes slide in the course of the longitudinal movement of the driven relative to the drive assemblies. Even more preferably the hardened surface of the inner sleeve in cooperation with the coaxial bushes permits said sliding movement under the influence of a bending moment imparted on the drive and driven assemblies in the course of operating the handheld tool. Still more preferably the actuated housing also includes a resilient seal mounted to the outer sleeve and arranged to seal with the inner sleeve to prevent the ingress of contaminants to an annular space between the inner and outer sleeves. 
     Preferably the handheld tool also comprises a drive coupling assembly connected to the drive assembly and arranged to provide coupling of a power source to the drive coupling assembly for actuation of the actuator sub-assembly. More preferably the drive coupling assembly includes a gearbox permitting coupling of the power source in a direction substantially perpendicular to a longitudinal axis of the actuator sub-assembly. Even more preferably the power source is in the form of an electrically powered and portable impact tool. 
     Preferably the drive assembly includes a thrust bearing mounted about the actuator shaft and within the actuator housing, said thrust bearing designed to accommodate axial forces associated with operation of the handheld tool. 
     Preferably the opposing jaw members are each detachably mounted to the actuator and the actuated housing, respectively. More preferably the jaw members are suited to the rail seat configuration to which the handheld tool is applied. Even more preferably the opposing jaws are capable of being reversibly mounted to either the actuator housing or the actuated housing depending on whether the tool is being operated to remove or apply the track fastener, respectively. 
     Preferably the handheld tool also comprises a saddle assembly mounted to the actuated sub-assembly and adapted to locate upon a railway track associated with the track fastener. More preferably the saddle assembly includes a bracket mounted to the adaptor sleeve, and an adjustable post moveably coupled to the bracket and adapted to rest upon a railhead of the railway track to assist in resisting a tipping moment whilst operating the handheld tool. 
     According to a second aspect of the invention there is provided a tool for installing or removing a railway track fastener, said handheld tool comprising: 
     a drive assembly including an actuator sub-assembly mounted for actuation within an actuator housing, the drive assembly also including a jaw member detachably mounted to the actuator housing and adapted to contact either a rail seat or the track fastener; 
     a driven assembly including an actuated sub-assembly operatively coupled to the actuator sub-assembly for longitudinal movement of the driven assembly relative to the drive assembly on actuation of the actuator sub-assembly, the driven assembly also including i) an actuated housing within which the actuated sub-assembly is housed, and ii) an opposing jaw member detachably mounted to the actuated housing and adapted to contact either the track fastener or the rail seat whereby in operation the longitudinal movement of the driven relative to the drive assemblies effects closing of the opposing jaw members relative to one, said jaws being reversibly mounted to either the actuator housing or the actuated housing depending on whether the tool is operated to remove or apply the track fastener, respectively. 
     Preferably the actuator sub-assembly includes an actuator shaft which actuates by rotation within the actuator housing. More preferably the actuated sub-assembly includes i) a threaded coupling arranged to be engaged by the rotating actuator shaft, ii) an adaptor sleeve mounted within the actuated housing and secured to the threaded coupling. Even more preferably the threaded coupling is in the form of an internally threaded nut arranged to be engaged by a corresponding external thread in the actuator shaft. 
     Preferably the external thread of the actuator shaft has a profile shape wherein rotation of the actuator shaft effects axial movement of the threaded coupling which is not back-driveable with respect to the actuator shaft. More preferably the actuator shaft includes an external thread of a trapezoidal, square or buttress profile. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a handheld tool for installing or removing a railway track fastener will now be described, by way of example, with reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view shown in part cross-section of a handheld tool for installing or removing a railway track fastener according to one embodiment of the invention; 
         FIG. 2  is an enlarged perspective view of the handheld tool of  FIG. 1  in conjunction with an associated railway track fastener and rail seat; 
         FIG. 3  is a side elevation shown in part cross-section of the handheld tool of the preceding figures; 
         FIGS. 4 and 5  are alternate perspective views of the handheld tool of the embodiment of the preceding figures. 
     
    
    
     DETAILED DESCRIPTION 
     As best seen in  FIG. 1 , there is according to one aspect of the invention a handheld tool  10  for installing or removing a railway track fastener  12 . The railway track fastener  12  is in this example a resilient fastener in the form of an e-clip. The e-clip  12  is configured in a conventional manner to secure railway track  14  to a rail seat  16 . The rail seat  16  includes sleeper  18  together with an insert or cast-in shoulder  20  which is engaged by the e-clip fastener  12  for securing of a foot  22  of the railway track  14  via an intermediate liner or biscuit  23 . In this embodiment the handheld tool  10  is powered by an electrically powered and portable impact tool in the form of a conventional impact wrench (not shown). 
     The handheld power tool  10  generally comprises a drive assembly  24  including an actuator sub-assembly  26 , and a driven assembly  28  including an actuated sub-assembly  30  operatively coupled to the actuator sub-assembly  26 . More particularly, the actuator sub-assembly  26  includes an actuator shaft  32  which actuates by rotation under the influence of the impact wrench (not shown) effecting longitudinal movement of the driven assembly  28  relatively to the drive assembly  24 . The drive assembly  24  of this embodiment also includes an actuator housing  34  in the form of an inner sleeve within which the actuator shaft  32  rotates. The drive assembly  24  further includes a jaw member  36  mounted to a bracket  38  extending from the inner sleeve  34 . 
     The driven assembly  28  of this embodiment includes an actuated housing  40  in the form of an outer sleeve within which the actuated sub-assembly  30  is housed. The driven assembly  28  further includes an opposing jaw member  42  mounted to an opposing bracket  44  extending from the outer sleeve  40 . In operation, the longitudinal movement of the driven assembly  28  relative to the drive assembly  24  effects closing of the opposing jaw members  36  and  42  relative to one another for installing or removing the e-clip fastener  12 . 
     In this embodiment the opposing jaw members  36  and  42  are each detachably mounted to respective of the brackets  38  and  44 . The jaw member  36  shown on the left hand side is adapted to contact the rail seat  16  or more particularly the cast-in shoulder  20  whereas the opposing jaw  42  seen on the right hand side is configured to contact the e-fastener clip  12 . In this configuration, the handheld power tool  10  on closure of the opposing jaw members  36  and  42  operates to install the e-clip fastener  12 . In order to remove the e-clip fastener  12 , the detachable jaw member  42  is mounted to the other of the brackets  38 . The other detachable jaw member  36  is replaced with a substitute jaw member (not shown) which is a variation on that jaw member  36  and suitable for contacting the rail seat  16  on an opposing side. In this configuration (not shown), closure of the opposing jaw members such as  42  effects contact with the cast-in shoulder  20  and the e-clip fastener  12  for its removal. 
     As best seen in  FIGS. 2 and 3 , the actuated sub-assembly  30  includes a threaded coupling  46  arranged to be engaged by the rotating actuator shaft  32 . The actuated sub-assembly  28  also includes an adaptor sleeve  48  mounted within the actuated housing or outer sleeve  40  and secured to the threaded coupling  46 . In this example, the threaded coupling  46  is in the form of an internally threaded nut arranged to be engaged by a corresponding external thread in the actuator shaft  32 . Although not illustrated, the external thread of the actuator shaft  32  has a trapezoidal profile shape wherein rotation of the actuator shaft  32  within the threaded nut  46  effects axial movement of the threaded nut  46 . The rotational force or impulse torque imparted intermittently on the actuator shaft  32  by the impact wrench in cooperation with the complementary threads effects axial movement of the threaded nut  46  relative to the actuator shaft  32 . The threaded nut  46  by the design of the complementary threads is not axially back-driveable and thus avoids reverse rotation of the actuator shaft  32 . 
     In operation of the handheld power tool  10 , the inner sleeve  34  on rotation of the actuator shaft  32  reciprocates within the outer sleeve  40 . The outer sleeve  40  is mounted coaxial with the adaptor sleeve  48  and together they coaxially align with the actuator shaft  32  which is mounted coaxial with the inner sleeve  34 . The actuated sub-assembly  30  includes a coaxial bearing  50  mounted to the threaded coupling or nut  46  and configured to slide within the inner sleeve  34 . The coaxial bearing  50  ensures the actuator shaft  32  remains concentric with the inner sleeve  34  to prevent deflection of the drive assembly  24  or the driven assembly  28 . 
     The actuated sub-assembly  28  also includes a pair of opposing keys  52   a  and  52   b  fixed to the adaptor sleeve  48  and arranged to slide for longitudinal movement within corresponding keyways  54   a  and  54   b  formed in the inner sleeve  34 . The keys  52   a/b  and corresponding keyways  54   a/b  are in transverse section shaped substantially complementary to one another. This keyed arrangement, on rotation of the actuator shaft  32  and the resulting longitudinal movement of the driven assembly  28  relative to the drive assembly  24 , prevents rotation or twisting of the actuated sub-assembly  30  and, in particular, the threaded nut  46  and the adaptor sleeve  48 . 
     In this embodiment the actuated housing or outer sleeve  40  includes a pair of axially separated coaxial bushes  56   a  and  56   b  arranged to slide along an outer journaled surface  58  of the inner sleeve  34 . The journaled surface  58  of the inner sleeve  34  is hardened where the coaxial bushes  56   a/b  slide, this hardening being effected by an electroless nickel or other alloy deposition process. The hardened outer journaled surface  58  of the inner sleeve  34  in cooperation with the coaxial bushes  56   a/b  permit sliding movement under the influence of a bending moment imparted on the drive assembly  24  and the driven assembly  28  in the course of operating the handheld tool  10 . The driven assembly  28  also includes a resilient seal  60  mounted to the outer sleeve  40 . The resilient seal  60  in the form of a wiper seal is arranged to seal with the inner sleeve  34  to prevent the ingress of contaminants to an annular space  62  between the inner sleeve  34  and the outer  40  sleeve. 
     As best seen in  FIGS. 3 to 5 , the handheld tool  10  also comprises a drive coupling assembly  64  connected to the drive assembly  24  and arranged to provide coupling of the power source or impact wrench (not shown) to the drive assembly  24 . In this embodiment the drive coupling assembly  64  includes a 90 degree gearbox  66  permitting coupling of the impact wrench in an upright orientation substantially perpendicular to a longitudinal axis of the actuator sub-assembly  34 . The drive assembly  24  as seen in  FIG. 3  also includes a thrust bearing  68  mounted about the actuator shaft  32  and radially supported within the inner sleeve  34 . The thrust bearing  68  is designed to accommodate axial forces associated with operation of the tool  10 . 
     The handheld tool  10  also comprises a pair of saddle assemblies  70   a  and  70   b  mounted to the drive assembly  24  and the driven assembly  28 , respectively. The saddle assemblies  70   a/b  are adapted to locate about the railway track  14  either side of the e-clip fastener  12  which is to be installed or removed. Each of the saddle assemblies such as  70   b  is of a similar construction including a support bracket  72   b  mounted to an annular flange  74  connected to the adaptor sleeve  48 , and an adjustable post  76   b . The adjustable post  76   b  is movably coupled to the bracket  72   b  and adapted to rest upon a rail head  78  of the railway track  14 . The saddle assembly  70   b  also includes upper and lower contact pads  80   b  and  82   b  positioned to contact the railhead  78  and the foot  22  of the railway track  14 , respectively. The saddle assemblies  70   a/b  either alone or in combination assist in resisting a tipping moment caused largely by the offset in the opposing jaw members  36 / 42  whilst operating the handheld tool  10 . 
     It is expected that the handheld power tool  10  of this embodiment will be relatively lightweight and nonetheless generate the relatively high force required to install or remove the track fastener. For example, the handheld tool  10  may weigh up to around 20 kg and generate a closing force between its opposing jaw members  36 / 42  of around 4 tonne. The handheld tool  10  is in this case powered by a high torque and battery powered impact wrench which produces torque of at least 100 Nm. The handheld tool  10  will generally provide longitudinal movement or displacement of the opposing jaw members  36 / 42  of up to around 100 mm relative to one another. 
     Now that a preferred embodiment of a handheld tool for installing or removing a railway track fastener has been described it will be apparent to those skilled in the art that it has the following advantages:
         1. the tool generates relatively high closing forces whilst being lightweight and thus capable of being operated by hand by a single person;   2. the tool is engineered to reduce bending moments which leads to its relatively lightweight construction which in turn allows it to be handheld;   3. the tool and in particular the telescopic inner and outer sleeve cooperate for sliding under the influence of bending forces imparted by the drive force of the drive assembly;   4. the tool is suitable for application to a range of differently configured rail seats by selecting and detachably mounting jaw members which can also be changed depending on whether the tool is used for application or removal of the track fastener.       

     Those skilled in the art will appreciate that the invention as described herein is susceptible to variations and modifications other than those specifically described. For example, the actuator sub-assembly need not be limited to the rotating actuator shaft but extends to other arrangements which effect the required longitudinal movement of the driven assembly relative to the drive assembly. The power source may vary from the impact wrench depending largely on the nature of the actuator sub-assembly. The drive coupling assembly may act axially in line with the tool rather than the 90 degree arrangement of the preferred embodiment. 
     In another aspect of the invention the tool need not necessarily be handheld. For example, the tool may be permanently or temporarily mounted to a relatively lightweight trolley which rests upon one or both rails with which the fastener is associated. In this variation the opposing jaws are detachably mounted to respective of the actuator housing and the actuated housing. The jaws are interchangeable or reversible with one another depending on whether the tool is operated to remove or apply the track fastener. 
     All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.