Abstract:
A drill mounted tool for installing collapsible deformable head fasteners includes a yoke supported on the drill housing carrying a reciprocal nosepiece rotatably coupled at a left hand threaded connection to an actuator shaft connected to the drill chuck. The actuator shaft has an external projecting right hand threaded end for carrying the fastener. Upon drill actuation, the actuator shaft extends the nosepiece relative to the actuator shaft thereby collapsing and deforming the fastener into secure engagement with a workpiece.

Description:
RELATED APPLICATION 
     The present invention claims the benefit of U.S. Provisional Application No. 60/235,603 filed on Jul. 27, 2000 in the name of Donald R. Thiede and entitled “Fastener Installation Tool”. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the installation of fasteners and, in particular, to a tool for installing collapsible fasteners. 
     BACKGROUND OF THE INVENTION 
     The present invention provides an installation tool for a class of fasteners consisting of axially compressible, radially expandable threaded fastener inserts that are attached to a workpiece and coupled with a threaded bolt to effect a mounting relationship with an associated component. The commercially available inserts, also know as rivet nuts and threaded inserts, are axially compressed by a suitable, thereby radially expanding and securing the fastener for permanent installation on a workpiece. 
     Inasmuch as substantial force is required to deform the fastener, specialized tools have been developed for facilitating installation. In one approach, as disclosed in U.S. Pat. No. 4,425,782 to Todisco, a hand held setting tool includes a mandrel having a threaded end for holding the fastener and an anvil for axially engaging the fastener against the workpiece. By compressing a pair of pivotal handles, the mandrel is upwardly telescoped relative to the mandrel, whereby the shank of the fastener is shortened causing radial expansion into secure engagement with the workpiece. Thereafter, the mandrel is manually unthreaded from the fastener to complete the installation. The tool requires that the operator use both hands to develop sufficient force to collapse the fastener, presenting safety concerns for installation in difficult to reach locations. Further, the multiple threading steps for mounting and releasing the fastener at the installation tool is cumbersome, time consuming and costly. 
     To overcome the foregoing limitations of the manual tools, a single purpose, air-powered setting tool, of the type disclosed in U.S. Pat. No. 4,045,994 to De Maio et al., has been proposed for threading the fastener onto the mandrel, collapsing the fastener, and unthreading the mandrel after installation. While somewhat automating the installation procedure and allowing single hand operation, such equipment is very costly, and not affordable to most operators. Further, the tool must be accurately preset to avoid stripping the insert threads during installation. 
     Accordingly, a need persists for an improved installation tool for collapsible fasteners that is affordable, easy to use, and provides high productivity. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an installation tool for collapsible deformable head fasteners that are automatically operated by widely available and affordable reversible drills. The installation tool includes a yoke assembly supported on the drill housing carrying a reciprocal nosepiece. An actuator shaft is coupled at an inert end to the drill chuck. The other end is provided with a right hand thread for carrying the fastener. An intermediate section of the actuator shaft includes a left hand thread section coupled to the nosepiece. Upon drill actuation, the actuator nosepiece extends relative to the yoke thereby collapsing the fastener into secure engagement with a mounting surface. 
     Accordingly, it is an object of the present invention to provide an installation tool for deformable insert rivet nuts that may be operated by a readily available power tool. 
     Another object of the invention is to provide an installation tool for collapsible fasteners that permits single-handed installation. 
     A further object of the present invention is to provide an installation tool connected to a conventional a reversible drill for safely and quickly installing deformable head fasteners to a workpiece. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The above and other objects of the invention will become apparent upon reading the following detailed description taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a partially sectioned top view of a fastener installation tool mounted on a variable speed drill in accordance with a preferred embodiment of the invention; 
     FIG. 2 is an exploded view of the installation tool shown in FIG. 1; FIG. 3 is a top view of the yoke of the installation tool shown in FIG. 1; 
     FIG. 4 is an end view of the yoke of the installation tool shown in FIG. 3; 
     FIG. 5 is a side view of the nosepiece of the installation tool shown in FIG. 1; 
     FIG. 7 is a right end view of the nosepiece shown in FIG. 5; 
     FIG. 8 is a cross sectional view of the nose piece shown in FIG. 5; 
     FIG. 9 is a side view of the actuator shaft of the fastener installation tool shown in FIG. 1; 
     FIG. 10 is side elevational view of the fastener on the actuator shaft in the mounting condition; 
     FIG. 11 is a partially section side view of the fastener at the workpiece prior to installation; and 
     FIG. 12 is a partially sectioned side view of the fastener in the installed condition on the workpiece. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings for the purpose of illustrating the preferred embodiment and not for limiting same, FIG. 1 illustrates a reversible portable electric drill  10  having a collapsible fastener installation tool  12  operatively coupled thereto. The drill  10  is a commercially available portable electric rechargeable model having a reversible motor for selectively reversing the rotation of a chuck  14 . The drill  10  is provided with a variable clutch  16  for limiting the torque applied at the chuck  14 . A suitable drill is available from DeWalt as model DW992 with a XR2 18 volt battery pack. 
     The installation tool  12  comprises a torque yoke  20  removably carried on the housing  22  of the drill  10 , a reciprocating actuator nosepiece  24 , and a dual threaded actuator shaft  26 . As described in greater detail below, the actuator nosepiece  24  is axially telescoped inwardly and outwardly through appropriate motor actuation of the drill  10  for installation of collapsible fasteners. 
     Referring to FIG. 10, a typical fastener  30  comprises a unitary cylindrical body including a threaded shank  32  and a skirt  34  integrally connected at an annular frangible section  36 . The shank  32  has a threaded bore  38  with a conventional right hand thread. The skirt  34  is provided with an annular flange  39  and an outwardly opening bore  40  having a diameter complementary to the outer surface  41  of the shank  32 . In installation, the fastener  30  is received in a clearance opening in a workpiece  42 . A suitable fastener is available as Thread-Sert fastener from Marson Creative Fastener, Inc. as Product No. 0128227. 
     By operation of the installation tool  12 , the fastener  30  is axially collapsed as shown in FIGS. 1 and 12 wherein the frangible section  36  is fractured and the shank  32  telescopes within the skirt  34  thereby shortening the fastener length and radially outwardly deforming the skirt  34  to effect axial and radial compressive engagement with the mounting panel  42 . 
     Referring additionally to FIGS. 5 through 8, the actuator nosepiece  24  comprises a head section  50  of hexagonal cross section and a shank section  52  of circular cross section. The head section  50  is provided with a threaded counterbore  54  of left hand thread. The shank section  52  is provided with a through bore  56  provided by the tap drill for the threaded counterbore  54  at a diameter sufficient to establish a clearance relation with the outer end of the actuator shaft  26 . 
     As shown in FIG. 9, the actuator shaft  26  comprises an actuator section  60  and a fastener section  62 . The actuator section  60  includes an outer cylindrical shank for receipt in the chuck  14  of the drill  10  and an actuator thread  66  of left hand thread for threaded engagement with the threaded counterbore  54  of the nosepiece  24 . The fastener section  62  includes a center section  68  having a clearance relation with the threaded counterbore  54  and terminating with a threaded end  70  of right hand thread for threaded engagement with tile fastener  30 . Accordingly, upon relative rotation of the nosepiece  24  and the shaft  26 , the threaded end  70  is shifted between an extended position shown in FIG. 10 and a retracted position shown in FIG.  12 . 
     Referring to FIGS. 3 and 4, the yoke  20  comprises a support sleeve  80 , a pair of mounting arms  82 , and a mounting clamp  84 . The support sleeve  80  includes a through bore  86  of a hexagonal cross section for axially telescopically supporting the head section  50  of the nosepiece  24 , and a cylindrical outer surface  88 . Each of the arms  82  has a generally rectangular cross section and includes a front section  90  fixedly connected to the sleeve  80  at welds  92 , an outwardly flared center section  94 , and a rearwardly extending rear section  96  connected to the outer surface of the mounting clamp  84 . The mounting clamp  84  includes a split cylindrical adjustable band  100  telescopically receivable over the frontal nose of the drill housing  22 , and a pair of circumferentially spaced, radially outwardly turned legs  102  adjustably interconnected by bolt and nut fastener assembly  104 . As will be apparent, the band  100  may be adjustably fixedly clamped to the nose section by adjustment of the fastener assembly  104 . 
     In operation, the yoke  20  is mounted on the drill  10  and the inner end  64  of the shaft  26  clamped in the jaws of the drill chuck  14 . The drill  10  is actuated to outwardly extend the installation end sufficiently to receive the fastener as shown in FIG.  10 . Holding the fastener, the drill is actuated to thread the fastener onto the outer threaded end  70 . The fastener  30  may then be inserted into a hole of a mounting component. With the fastener securely engaging the workpiece, the drill  10  is reversely actuated, and the actuator thread  66  rotates relative to the yoke sleeve  88  thereby retracting the bit  26  relative to the nosepiece  24  until the end of the nosepiece engages the flange  39  as shown in FIG.  11 . Further rotation and initiates fracture of the frangible section  39 . Further compression results in the installation condition shown in FIG. 12 wherein the skirt of the fastener is radially outwardly expanded for effective mechanical compressive engagement with the mounting component. Upon achieving the installation condition, the torque on the bit  26  substantially increases effective for releasing the clutch on the drill  10 . The torque increase is also sufficient to provide operator indication for assembly with non-clutch drills. Upon satisfactory completion, the drill is reversed to unthread the actuator shaft from the fastener. 
     For accommodating varying sizes of fasteners, a plurality of sleeve and bit subassemblies may be provided. For accommodating varying drills, the clamp assembly may be suitably adapted. 
     Having thus described a presently preferred embodiment of the present invention, it will now be appreciated that the objects of the invention have been fully achieved, and it will be understood by those skilled in the art that many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the sprit and scope of the present invention. The disclosures and description herein are intended to be illustrative and are not in any sense limiting of the invention, which is defined solely in accordance with the following claims.