Driving attachment for eye-bolt hangers and the like

A pair of jaws, having two sets of mutually perpendicular surfaces which are oriented 45 degrees with respect to the direction of jaw motion. During adjustment the jaws move parallel to each other to accommodate different shank diameters. The opening and closing of the jaws for receiving and clamping a shank is accomplished by an overcenter toggle assembly that produces a combination of parallel and rotational motion which secures the shank against the two mutually orthogonal surfaces of the jaw.

BACKGROUND 
1. Field of the Invention 
This invention relates to a portable drill attachment, specifically all 
attachment which can be used to drive eye-bolts, J-bolts, screw hooks, and 
other hanger-type devices which cannot be "chucked" because of their 
physical configuration. 
2. Discussion of Prior Art 
Eye bolts with lag threads are commonly used to hang loads from overhead 
locations such as beams and ceilings as well as walls, trees and other 
structures. po In the usual procedure, the worker will either hammer the 
eye-bolt into the material (typically wood) to grab a few threads, or he 
will pre-drill a pilot hole; in either case the threaded shank is 
thereafter manually screwed into the material using pliers or some other 
leverage effecting device. The procedure is both cumbersome and time 
consuming--and generally requires several different tools. Moreover, 
unless a pilot hole is drilled, the starting process can be frustrating 
and difficult since hammering is likely to deform the end (in the case of 
eye-bolts, the eye is deformed whereas off axis hangers such as J-bolts 
and square bent hooks are difficult to hammer and more likely therefore to 
become damaged or distorted). 
The desirability of a device which is sufficiently universal to accommodate 
a wide range of hanger types and sizes so as to facilitate their rapid 
installation will be readily appreciated. Accordingly, it is a primary 
object of the invention to provide a driving attachment for a portable 
drill which can be used efficaciously for a wide range of hanger types and 
sizes, including but not limited to: 
(a) shank diameters ranging from 1/16" to 7/16" 
(b) head dimensions ranging from 1/8" to 11/4" 
(c) head configurations including round, L, J, offset round, square, and 
combinations thereof. 
It will be understood that to accomplish these objectives with a single 
device, the invention must effectively meet and resolve numerous 
difficulties, thus 
(a) for different shank diameters, 
1) the torque must be axially centered by the gripping elements and, 
2) the shank neck must be mechanically restrained so as to maintain the 
thrust axis alignment. 
(b) for different head dimensions, the point of application of the axial 
force must be centered with the torque axis. 
(c) for different head configurations, the point of application of the 
axial force must line up with the torque axis. 
OBJECTS AND ADVANTAGES 
Accordingly, other objects and advantages of the invention are: 
(a) to provide an attachment for installing eye-bolts, J-bolts, screw 
hooks, and the like, using a manual or power drill. 
(b) to provide a driver that eliminates the need to hammer a starting 
indentation or the need to drill a pilot hole. 
(c) to provide a driver that has universal applicability so as to cover a 
wide range of shank sizes, eye diameters, and end shapes. 
(d) to provide a driver that aligns the screw axis true to the torque axis 
for all shank sizes and hanger shapes. 
Further objects and advantages of the invention are to provide a driver 
that shortens the installation time and eliminates the fatigue involved in 
manual installation. Other objects and advantages will become apparent 
from a consideration of the ensuing description and drawings. 
SUMMARY OF THE INVENTION 
A pair of parallel linkage assemblies can be used to maintain the parallel 
orientation of separately adjustable jaws. Each jaw includes a pair of 
mutually orthogonal surfaces which function to secure different shank 
sizes when they are brought together by actuation of an overcenter toggle. 
The assembly permits a wide variety of hanger shapes and sizes to be 
installed using a portable electric drill.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring to the drawings, and particularly FIG. 1, there is shown a pair 
of jaws comprising a left jaw clement 10A and a right jaw element 10B, 
each of which is constructed to have left and right complimentary surfaces 
12A and 12B for gripping a hanger shaft, and left and right hand clamping 
surfaces 14A and 14B for retaining the location of the hanger in position 
when axial thrust is applied. In order to facilitate the gripping of a 
wide range of shaft sizes, the jaws 10A and 10B must maintain the parallel 
orientation of these surfaces (12A parallel with 12B) and (14A parallel 
with 14B) as they move inwardly to engage the shaft. This function is 
achieved by two separate bifilar configurations, namely a left parallel 
linkage assembly 20, the motion of which is determined by the location of 
pins 61, 62, 63 and 64 which define the spatial orientation of the left 
jaw 10A as it moves toward the right jaw 10B which itself moves parallel 
to jaw 10A by virtue of the right parallel linkage assembly, its motion 
being in a like manner determined by the location of pins 61', 62', 63' 
and 64'. 
The left parallel linkage assembly 20 is comprised of four linkages 21, 22, 
23 and 24, jaw 10A, linkage 34, and pins 61, 62, 63 and 64. The right 
parallel linkage assembly is comprised of complimentary mirror image 
elements which function identical to the left parallel linkage elements. 
Both the left and right parallel linkage assemblies include an adjustment 
feature which functions to change the diagonal distance of travel of the 
jaws 10A and 10B to accommodate various shank diameters. The left jaw 
adjustment assembly is comprised of thumb screw 27, and an adjustment 
member 26 which pivots about pin 64 at the end of body 50 through the slot 
56. Member 26 has a slot 28 of sufficient width to accommodate post 62. 
Advancing thumb screw 27 into the threaded hole 29 of adjustment member 26 
shortens the diagonal distance between pin 64 and pin 62 thus moving jaw 
10A in the direction of closure. An identical set of mirror image elements 
allow jaw 10B to be likewise adjusted with respect to pin 62'--in essence, 
the location of pins 62 and 62' within the slots 28 and 28' of members 26 
and 26''respectively determine the spacing between the jaws 10A and 10B 
prior to clamp down. The two surfaces 12A and 12B are parallel to each 
other as are the surfaces 14A and 14B. Preferable these complementation 
pairs of surfaces are perpendicular to each other so as to optimize the 
retention force when the jaws 10A and 10B are brought together so that 
these pairs of surfaces can forcefully engage a hanger shaft as shown in 
FIG. 2. 
To recapitulate, the parallelogram type motion of the jaws is produced by 
the motion of the linkages and pins. Specifically, for the left jaw 10A 
the forward linkages 21 and 23 of the left parallel linkage assembly 20 
rotate about pin 64 over and under the body 50 respectively while the rear 
linkages 22 and 24 rotate through the same angle about pin 63, over and 
under the body 50 respectively. A similar corresponding motion of the 
right jaw 10B is produced by the right parallel linkage components. 
As seen from FIG. 1, the linkages 32, 34, 36, 38 together with pins 63, 
63', 64, 65 form an over-center toggle clamp 30 which is more particularly 
described as follows: 
"Linkages 32 and 34 pivot about pin 64 so as to move outwardly by virtue of 
linkages 36 and 38 when pin 65 is pulled forward in slot 54 by a torque 
action against lever 44 which rotates about pin 64. Pin 42 engages closure 
linkage 46 which communicates the torque applied to lever 44 via pin 65 to 
linkages 32 and 34 so as to cause the combination of linkages (i.e., 
38-22) and (36-22') to move pins 63 and 63' outwardly. As a consequence 
the torque applied to the lever 44 is converted to a clamping force 
between the surfaces 12A and 12B when the left and right bifilar 
assemblies have been pre-adjusted by thumb screws 27 and 27' to 
accommodate a particular shaft diameter. It will be understood that the 
action of toggle clamp 40 is such as to cause pin 65 to slide in slot 54 
of body 50 so that both the left and right assemblies remain symmetrically 
disposed to one another at all times. Closure of toggle damp assembly 40 
is thus effectuated via closure pin 42, lever 44, closure linkage 46, pin 
65 being pulled toward pin 64 within slot 54 as lever 44 is manually 
rotated about pin 64 until pin 42 has rotated to a point slightly beyond 
the center line connecting pins 65 and 64 in order to overcenter lock the 
apparatus until a manual torque is applied against lever 44 in the 
opposite direction." 
Retaining rings or keepers (i.e., 72) are used throughout to hold the 
assembly together. Spacer 74 occupies the gap which exists between linkage 
36 and closure linkage 46. Torsion spring 76 wraps around the extended 
portion of pin 63, and end of spring 76 being arranged to push upon the 
extended portion of pin 62 to bias the parallel linkage assembly toward 
the open parallelogram position. The other end of spring 76 pushes against 
the extended portion of pin 65 so as to urge toggle damp assembly 30 
toward the open jaw position, these biases having a tendency to make the 
adjustment and loading easier. 
From the description above, a number of advantages are readily apparent: 
(a) the device is universally functional, and can be used with any standard 
manual or power drill. 
(b) the invention eliminates the need to pound or drill a starting hole. 
(c) the device can be made in different sizes--to cover a vast variety of 
hangers. 
(d) the assembly will drive the screw axis true to the driving axis 
regardless of the shank diameters or hanger configuration. 
OPERATION 
Adverting again to FIG. 1, the typical procedure for using the invention 
would involve the steps of inserting the drive shaft 52 in a conventional 
portable drill chuck (not shown). The shank portion of the hanger is then 
positioned between jaws and the two thumb screws 27 and 27' adjusted 
equally so that the two jaws 10A and 10B will center the hanger screw axis 
in line with the rotational axis of shaft 52 when lever 44 is operated to 
close. Once this pre-adjustment is made, lever 44 can be rotated to secure 
the shank; thereafter, for a given size shank, no further adjustments are 
necessary. FIG. 2 shows the position of the jaws 10A and 10B as they would 
appear after lever 44 is moved so as to lock the shank of the eye-bolt 78. 
SCOPE 
The apparatus disclosed herein is versatile and convenient. It eliminates 
the need to hammer start (or drill holes) and it eliminates the time 
intensive task of manual installation. 
Although the description above contains many specificities, these should 
not be construed as limiting the scope of the invention but merely as 
descriptive of a preferred embodiment. For example, lever 44 can pivot 
from pin 65 capturing pin 63 at mid point then extend outward instead of 
closer to toggle clamp 30; shank portion of drive shaft 52 can be 
hexagonal instead of round; two separate compression springs, one in 
adjuster diagonal 26 to push against pin 62, the other in body 50 pushing 
against pin 65 to do the same work as torsion spring 76, etc. Thus the 
scope of the invention should be determined by the appended claims and 
their legal equivalents, rather than by the example given.