Abstract:
A multi-part handle system that incorporates bumper flanges disposed at opposite ends of a rigid handle device is proposed. The handle mounts to a manual tong apparatus, or any other piece of heavy equipment, by means of weldable or integrally cast brackets and provides a rigid but shock absorbing grip for the operator&#39;s hand. In the event that the bumper flanges become damaged or are torn off the handle assembly the rigid handle device will continue to provide a safe manipulation means while replacement bumpers are located. In contrast to prior art safety handles, rig operators will be able to deploy safety handles without the fear of lost rig time if the bumper components become damaged. A soft ergonomic grip cover is incorporated into the preferred embodiment of the safety to make gripping the handle assembly more comfortable and tactile for the operator.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     None. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to the use of safety handles that are placed about the periphery of heavy equipment to protect the operator&#39;s hands from injury. More particularly, the invention relates to safety handles that are mounted to the periphery of manual pipe tongs, which are typically used in the oilfield drilling industry. More particularly still, the invention relates to multi-piece, reinforced, and replaceable handles for manual pipe tongs that protect oilfield workers&#39; hands from injury that might otherwise result from impact with adjacent equipment. 
     2. Description of the Related Art 
     Manual pipe tongs are used throughout the oilfield industry to apply torque to various tubular components of generally cylindrical shape. This application of torque is most often used to secure, tighten (make-up), and loosen (break-out) the threaded rotary connections of drill pipe, drilling collars, casing and tubing. Pipe tongs typically function by incorporating a cantilevered configuration that holds the workpiece in a grip that tightens or loosens depending on the direction that torque is applied to the lever arm. 
     FIG. 1 shows a typical prior art manual tong assembly  10  as used in oilfield drilling operations to secure or rotate a cylindrical workpiece  12 . Manual tong assembly  10  includes a long jaw  14 , a short jaw  16 , a lug jaw  18 , and a lever arm  20  all connected together at pivot points  22   a, b, c, d.  A latch  24  is pinned to one end of the long jaw  14  and fits into a receiver step  26  at the end of the lug jaw  18 . 
     FIGS. 2 a  and  2   b  show how different workpiece  12  sizes can be accommodated by adjusting the lengths and configurations of lug jaw  18 . FIG. 2 a  shows the lug jaw  18  of FIG. 1 that includes an array of mounting locations  28  and a choice of receiver steps,  26  and  30 , that may be used to adjust the manual tong apparatus  10  to various diameters of workpiece  12  (e.g. pipe diameters). Alternatively, FIG. 2 b  details a lug jaw  32  that is longer in length and includes a hinged portion  34  attached to the lug portion  36  by means of a hinge pin  38  so as to allow even larger diameter workpieces to be accommodated by tong assembly  10 . 
     Referring again to FIG. 1, jaws,  14 ,  16 , and  18  are positioned in place around workpiece  12  and locked into place with latch  24 . In some instances, each jaw may contain one or more sets of sharpened teeth called tong dies  40  that are used to “bite”) into workpiece  12  and prevent slippage when manual tong  10  is engaged. Once latch  24  is engaged, lever arm  20  can be rotated in direction α so as to load latch  24  in tension and engage and apply torque to workpiece  12  in that direction. Rotating lever arm  20  in direction ω will loosen the grip of jaws ( 14 ,  16 , and  18 ) on workpiece and allow latch  24  to be opened. Because tool  10  is quite large, with lever arm  20  typically being 3-6 feet long, operation usually requires more than one person. Several handles, such as  42  or  44 , are typically placed about the periphery of manual tong assembly  10  to provide locations for rig workers to guide it when moving tong assembly  10  into position on the pipe, or to remove it from the pipe. 
     Manual tong  10 , as illustrated, is configured to grip workpiece  12  only when torque is applied in the α direction. Typical rig operations incorporate two sets of manual tongs, with each being a mirror image of the other, so that one tightens in clockwise direction and the other in a counter-clockwise direction. Each can tighten or loosen the pipe threads, depending on whether it is installed in the upper position and engages the pin (male) connection or the lower position for engaging and holding the box (female) counter. Typical operations will include the use of two, opposed tongs. When more than one tong is used, their positions on the workpiece relative to each other depends on the operation being performed and the type of additional rig equipment used. 
     Operators typically position and manipulate manual tongs  10  by grabbing handles that are provided about the periphery of the tongs as, for example, handles  42  and  44  in FIG.  1 . FIGS. 3 a,    3   b,  and  3   c  show three different designs of tong handles that have been previously known and used on manual tong assemblies. FIG. 3 a  shows a manual tong apparatus that includes a handle  50  made from U-shaped a cylindrical rod that has been cast or welded onto the body  52  of the tong. To manufacture handle  50 , the cylindrical rod is bent into top, middle, and bottom sections  54 ,  56 ,  58 , respectively. Although this design is the simplest and most cost effective for a manual tong manipulator handle, it offers the least protection to the operator, as a hand wrapped around handle  50  is exposed to blows from above, below, or horizontally. 
     In order to gain maximum protection from injury while using tongs with a handle of this design, the operator must fight his natural tendency to place his hands on top  54  and bottom  58  portions and must grip only middle portion  56  of handle  50 . This is because serious injury can result to an operator&#39;s hands when he is manipulating one set of tongs around the pipe while another set of tongs is being manipulated around the pipe, either above or below his tongs. If an operator&#39;s hand is exposed while two sets of adjacent tongs move relative to each other, it can be pinched or crushed between the tongs. The design of FIG. 3 a  offers little protection from injuries of this type, as the operator is comfortably able to grip the handle in any number of unsafe ways. 
     FIG. 3 b  demonstrates a handle system  60  that is designed to prevent the type of hand injuries experienced while using the design of FIG. 3 a.  Handle  60  includes a tong body  62  with a rod-style handle  64  as before, but with the addition of metal guard plates positioned in a horizontal plane of each end of vertical handle  64 . Metal guard plates  66  and  68  are intended to both restrict placement of hands to the center section of handle  64  and to protect the operator&#39;s hands from being crushed or impaled by an adjacent tong or other nearby equipment. Metal plates  66  and  68  can be either cast or welded into place as original equipment when the tong body  62  is manufactured or can be retrofitted to existing tongs as a safety upgrade. While the addition of metal plates  66 ,  68  is an improvement to the handle assembly  50  of FIG. 3 a,  they do not offer any shock absorbing characteristics. If an operator were to have a hand resting upon metal plates  66 ,  68  and that hand were to be impacted by another object, it is possible that the operator&#39;s hand or fingers could become crushed or severed. To ensure that tong handle devices pose as little safety risk as possible, it is best that they be manufactured or retrofitted with shock absorbent devices. 
     FIG. 3 c  shows another embodiment for a tong handle, which utilizes a one-piece polyurethane dumbbell-shaped design to address the shock absorbency concerns of handle  60  of FIG. 3 b.  Polyurethane dumbbell  70  is attached to tong body  72  by cutting out middle portion  56  in FIG. 3 a  and utilizing horizontal portions  54  and  58  ( 74  and  76  in FIG. 3 c ). One-piece dumbbell  70  includes a generally cylindrical handle section  78  with disc shaped flange portions  80 ,  82  above and below handle section  78 . Holes are drilled for spring pins in the ends of horizontal members  74  and  76 , and one-piece dumbbell  70  is fitted onto horizontal members  74  and  76 . Separate spring pins,  84 ,  86  are driven through opposite ends of dumbbell handle  70 , to engage horizontal members  74  and  76  and hold dumbell  70  in place on tong body  72 . Flanged portions  80  are preferably larger in diameter than an operator&#39;s fist so that they are able to act as large bumpers to protect operator&#39;s hands from damage. 
     Dumbbell  70  is manufactured of a shock absorbing material. When operator uses dumbbell handles  70  to manipulate manual pipe tongs, his hands are protected from impact and scrapes with other equipment as long as his hands are positioned on cylindrical handle section  78 . Unfortunately, the dumbbell design of FIG. 3 c  has drawbacks that can reduce its effectiveness, preventing many drilling contractors from adopting it. 
     One-piece dumbbell  70  is sometimes installed as a retrofit on tongs with existing handles as shown in FIG. 3 a.  The vertical distance between existing horizontal members  74  and  76  in FIG. 3 c  is typically different for various handle locations on the same tong, and of course, on different tong models. Due to the need for economical production of a one-piece molded dumbbell handle  70 , one size of one-piece dumbbell handle  70  is utilized in as many different locations as possible. This results in some compromises in fitting, such that one-piece dumbbell handle  70  is sometimes installed in a slightly bent or compressed or stretched or loose condition, which may contribute to a premature failure of this part. 
     Because the material of dumbbell  70  must be somewhat soft in order to have good shock absorbing properties, it is also somewhat flexible. The flexibility of handle portion  78  can cause it to break and tear away prematurely. In the event of a failure of handle portion  78 , dumbbell  70  is unusable and must be replaced before the tong  72  can be safely operated again. If a replacement is not immediately available, since minimal amounts of replacement parts are typically carried on the work location, a drilling rig crew might be tempted to manipulate the manual tong apparatus outside the designated handle area  78 , such as by grasping  74  and manipulating tong  72  with hands outside the protected area between  74  and  76 . This temptation to use the crippled tong assembly in an unsafe manner, while parts are on order, results in greatly increased risks to the health and safety of the operator. 
     Because of the increased potential for injury in the event of a failure of this design, drilling operators may be reluctant to deploy dumbbell handles  70  with their manual tong assemblies, thus not taking advantage of any safety improvements that that may otherwise be realized. Hence, it is desirable to provide an effective manual tong handle that is safer, more reliable, and reduces the risk of injury. 
     BRIEF SUMMARY OF THE INVENTION 
     The need noted above can be addressed in large part by a multi-part handle system that incorporates bumper flanges disposed at opposite ends of a rigid handle device. The present system attaches to a manual tong apparatus, or any other piece of heavy equipment, by means of weldable brackets securely attached to the handle device. The present new design includes bumper flanges that provide shock absorbing protection for the operator&#39;s hand, while the handle device provides rigidity and durability. In the event that the bumper flanges become damaged or are torn off the handle assembly, the rigid handle device will continue to provide a safe manipulation means until replacement bumpers are obtained. This feature offers a dramatic improvement, as it allows rig operators to deploy safety handles without the fear of lost rig time if the bumper components become damaged, a situation that designs of the prior art do not effectively address. Additionally, a soft ergonomic grip cover is incorporated into the preferred embodiment of the present invention to make gripping the handle assembly more comfortable and tactile for the operator. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a detailed description of a preferred embodiment of the invention, reference will now be made to the accompanying drawings wherein: 
     FIG. 1 is a drawing of a prior art manual tong apparatus; 
     FIG. 2 a  is a detail drawing of a lug jaw of the prior art manual tong apparatus of FIG. 1; 
     FIG. 2 b  is an alternative embodiment of the lug jaw of FIG. 2 a;    
     FIG. 3 a  is a close up view of a manipulation handle of the manual tong apparatus of FIG. 1; 
     FIG. 3 b  is a close up view of an alternative embodiment to the manipulation handle of FIG. 3 a;    
     FIG. 3 c  is a cross-sectional view of another alternative embodiment to the manipulation handle of FIG. 3 a;  and 
     FIG. 4 is a cross-sectioned view of a handle apparatus for a manual tong assembly in accordance with the preferred embodiment of the present invention; 
     FIG. 5 is an isometric view of the top and back of the elastomeric flange of FIG. 4; 
     FIG. 6 is an isometric view of the bottom and front of the elastomeric flange of FIG. 4; 
     FIG. 7 is an isometric drawing of the attachment plate of FIG. 4; and 
     FIG. 8 is a sectioned drawing of the handle member of FIG.  4 . 
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 4-8 show components of a preferred embodiment of a novel multi-piece safety handle for an oilfield manual pipe tong device. Referring initially to FIG. 4, a multi-piece safety handle assembly  100  is shown attached to a manual tong device  102 . Handle assembly  100  includes two bumper flanges  104 , a rigid handle member  106 , an elastomeric grip cover  108 , a retainer  110 , and flat washers  112 . Handle assembly  100  is secured to tong body  102  by two attachment plates  114 . Attachment plates  114  are positioned on the exterior of tong body  102  in the desired location of handle assembly  100  and are preferably affixed to tong body  102  by welds  116 . 
     FIG. 5 details a top-back isometric view of bumper flange  104  and FIG. 6 details a bottom-front isometric view of the same component. While the following discussion relates to upper bumper flange  104 , it will be understood that the same concepts and features are preferably applied to lower flange  104 , although in an inverted manner. Referring to FIGS. 5 and 6 concurrently, it can be seen that the preferred embodiment of bumper flange  104  includes an outer profile  120 , a top face  122 , and a bottom face  124 . Filleted, or radiused, transition portions  126  exist between both faces,  122  and  124 , and outer profile  120 . Additionally, a flat faced feature  128  is located on profile  120 , towards the back of bumper flange  104  between top  122  and bottom faces  124 . A bore hole  130  extends through bumper flange  104  from top face  122  to bottom face  124 . A countersink  132  is coaxial with bore  130  and extends from top face  122  partially through flange  104 . Extending from flat face  128  into the interior of bumper flange  104  is an attachment plate socket  134  that fits the cross section width of attachment plate  114 . Located in the bottom face  124  of bumper flange  104  is a radial ergonomic cutaway  136  that allows the operator more clearance for ease and range of motion when gripping handle assembly  100 . Bumper flanges  104  are preferably manufactured of a elastomeric compound with a durometer hardness less than 100 Shore-A, more preferably of an elastomeric compound with a durometer hardness less than 70 Shore-A. Bumper flanges  104  are preferably manufactured of polyurethane, but any suitable shock absorbing material may be used. 
     An isometric view of an attachment plate  114  in accordance with the preferred embodiment is shown in FIG.  7 . Attachment plate  114  has an attachment end  140 , and a handle end  142 . Handle end  142  includes a clearance hole  144  while attachment end  140  includes tapers  146  to facilitate welding. The exterior profile of handle end  142  is sized and shaped so that it fits snugly within the socket  134  of bumper flange  104  of FIG. 5, with clearance hole  144  aligning with bore  132 . 
     FIG. 8 details rigid handle member  106  from FIG.  4 . Handle member  106  preferably includes a bolt head  150 , a smooth body portion  152 , and a threaded end  154 . Smooth body portion  152  is sized to fit snugly within clearance holes  144  of attachment plate  114 , and within bore  130  of bumper flange  104 . Threaded end  154  of handle member  106  is preferably of equal or smaller diameter to smooth body portion  152  and engages corresponding threads of retainer  110  of FIG.  4 . The preferred embodiment of the present invention uses a standard hex head screw to perform the duties of handle member  106  although a different or more customized component may be substituted in its place. 
     Referring again to FIG. 4, the installation and assembly of safety handle assembly  100  can be described. First, the desired location of safety handle assembly  100  must be identified about the perimeter of manual tong body  102 . Once the installation location has been identified, the existing handle device, if there is one, must be removed. Any method of removal is acceptable as long as the mounting locations are left in a condition suitable for welding. 
     Once the mounting location has been properly prepared, attachment plates  114  can be installed. Attachment plates  114  are preferably installed by placing them in their desired positions and securing them in place with welds  116  above and below plates  114 . The relative position of the plates is determined by the specific application and can be at any orientation as long as the clearance holes  144  of the two attachment plates  114  line up coaxially with one another. The relative distance between the two plates  114  is a function of the amount of hand height clearance d desired by the operator. Typical installations will utilize a d value of approximately 6-8 inches but more or less hand height clearance can be used, depending on the space limitations of the equipment. Following weld installation of attachment flanges, regions surrounding the weld areas should be properly stress-relieved in accordance with appropriate manufacturing procedures. For installations where attachment by welding is not feasible or desirable, other attachment methods may be incorporated into the design of the attachment places. Such methods include but are not limited to brazing, soldering, upsetting, threading, riveting, and pinning. Of course, new cast tong parts  102  may include attachment plates  114  as an integral part of original casting such that welding or other attachment methods are not required. 
     Once attachment plates  114  have been properly mounted and heat treated, handle assembly  100  can be attached as follows. First, bumper flanges  104  are fitted snugly over the handle ends  142  of attachment plates  114 , making sure to orient them so that ergonomic cutaways  136  are oriented away from tool body  102 , as shown in FIG. 4, or as otherwise desired. It is preferred that bumper flanges  104  fit snugly onto attachment plates  114  to increase the long term durability of the handle, as loose fitting bumpers  104  can experience premature wear. Following the mounting of bumper flanges  104 , a washer  112  is placed within counterbore  132  of top bumper flange  104  and handle member  106  is inserted through washer  112 , bumper flange  104 , and attachment plate  114 . Once handle member  106  has passed through top bumper flange  104 , grip cover  108  is positioned between bumper flanges  104  so that handle member can engage cover  108 , bottom bumper flange  104  and aligned with bores  130 , and handle member  106  is inserted the rest of the way through cover  108 , lower bumper  104 , and bottom attachment plate  114 , until head  150  rests on upper washer  112 . Once fully engaged, lower washer  112  is installed and retainer  110  is threaded onto threaded end  154  of handle member  106 . 
     Connecting bumper flanges  104  to attachment plates  114  in this manner allows bumper flanges  104  to be easily removed and replaced. Additionally, rigid handle member  106  provides a primary gripping device that is effectively integral with manual tong  52 . Therefore, if bumper flanges  104  are damaged or somehow become detached from handle assembly  100 , the remaining handle components can continue to be used without interrupting rig operations if replacement bumpers are not immediately available. 
     Grip cover  108  is preferably constructed of a material that provides a comfortable and tactile surface for the operator&#39;s hand. The material for grip cover  108  is preferably an elastomeric compound that is relatively soft in comparison to material of grip member  106 . Additionally, grip cover can be manufactured with a smooth, textured, or hand contoured surface to enhance gripping ability and reduce slippage. 
     In comparison to the one-piece dumbbell handle  78  of FIG. 3 a,  multi-piece assembly  100  offers all the protective capabilities of the prior art design, but is significantly more durable. Hence, the present multi-piece handle assemblies  100  can be deployed throughout the oilfield drilling/work over rig industry without the concerns of ruggedness that arise with the one-piece dumbbell  70  of the prior art. Furthermore, while though the multi-piece safety handle assembly  100  of the present invention is described above as a component for a manual tong device, the concept can be incorporated with little modification into any piece of heavy equipment. 
     In alternative embodiments, bumper flanges  104  can be configured such that they are wholly between or wholly outside of attachment plates  114 . That is, it is preferred but not necessary that attachment plates  114  engage corresponding recesses  134  as recited above. If flanges  104  were positioned outside of plates  114 , they would be sandwiched between head  150  and upper plate  114  and between retainer  110  and lower plate  114 , respectively. If flanges  104  were between plates  114 , it would be necessary to provide an alternative support mechanism, such as a shoulder on handle member  106  or the like. Alternatively, bumper flanges  104  could be formed integrally with grip cover  108 , although this embodiment is not preferred. 
     In another alternative embodiment, handle member  106  is used with only a single attachment flange and with one or two bumper flanges  104 . In this embodiment, threaded connectors are used to maintain handle  106  in its desired position relative to the one attachment flange. This embodiment does not provide the full circle of protection that is provided by the preferred embodiment, but may nevertheless sometimes be preferable, such as, for example, when there is not sufficient vertical space on the equipment in question to mount a pair of attachment flanges. 
     The above discussion is meant merely to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. For example, the relative dimensions and geometries of various parts, the materials from which the components are made, the manner in which certain pieces are connected, and other parameters can be varied. The scope of the following claims should not be limited by the description set out above.