Pneumatic decking crimper

A power assisted crimping tool is disclosed particularly suited to crimping and dimpling of structural steel decking and roofing panels together. The invention comprises a frame supporting a pair of jaws which are opened and closed by means of a toggle linkage that is driven by an operator-controlled pneumatic cylinder. The input pivot of the toggle linkage is constrained to move linearly by means of a cross head formed in the frame which, in turn, causes the jaws to move in unison rather than one jaw moving against the other. According to one embodiment, the jaws are provided with a plurality of punch and die sets disposed in opposite orientations, such that as the decking or roofing panel joint is crimped by the jaws, the punch and die sets raise a plurality of dimples having alternating orientations. The alternating dimples provide a substantial increase in the lateral resistance (shear strength) of the crimped seam, thereby obviating the need to additionally weld or screw the seam to provide the necessary shear strength.

BACKGROUND OF THE INVENTION 
The present invention relations to hand tools for forming crimp joints in 
structural steel decking and roofing commonly used in large commercial 
construction for example as subflooring for poured concrete floors or as 
roofing for large industrial buildings. Structural steel decking is 
typically manufactured in thicknesses ranging from 22 gauge to 16 gauge or 
more. The decking generally is supplied to the building site in panels 
ranging in size from 3 feet by 15 feet to about 3 feet by 35 feet. 
Longitudinal ribs, typically hat sections or flat-bottomed vee sections of 
from 11/2 to 3 inches in depth are formed in the panels to increase the 
section modulus of the panels. The individual panels are typically 
provided with one edge having an exposed upward "male" lip. The opposite 
edge is provided with a female inverted "U" shaped lip. The individual 
panels are joined together by placing the female lip over the male lip and 
crimping, welding, or screwing the seam at periodic intervals. In many 
applications, the joints must secure the panels together so as not only to 
prevent one panel from lifting off the other, but also to prevent the 
panels from shifting laterally along the seam (along the x-axis as shown 
in FIG. 1). By holding the panels securely enough to prevent lateral 
shifting, the assembled decking adds considerable membrane strength to the 
assembled building. Given the inherent weakness of crimped joints to 
lateral shifting, typically where high membrane strength was required, 
welding or screwing the seam has been specified. 
A prior art method for crimping steel decking comprises use of a 
hand-operated tool shown in FIG. 1, known as the 601 SEAM LOCKER 
distributed by Miramar Specialties of Ventura Calif. The prior art 
apparatus comprises a compound-lever press in which the operator moves the 
handles apart to provide the force to crimp the panels together. An 
optional button punch is provided to upset a portion of the seam to 
provide some lateral stiffness. Since the apparatus comprises merely a 
compound lever arrangement, however, it provides a linear multiplication 
of the force exerted by the operator on the handles. As can be appreciated 
from the foregoing, hand crimping of thousands of seams is a laborious 
task and, given the inevitability of operator fatigue, an inherently 
unreliable method for providing seams having the uniformity necessary to 
compete with welded and screwed joints in the high stress applications. 
Various portable power tools have been developed for setting rivets, 
crimping sheet metal trusses, and for other applications. For example, 
U.S. Pat. No. 1,743,209 to Groehn discloses a fastener setting device 
comprising a toggle-actuated jaw and anvil adapted for setting rivets, 
particularly in the construction of automobile bodies. U.S. Pat. No. 
3,877,280 to Cornell discloses a hand operated power assisted punch and 
die for crimping sheet metal studs and joists together to form a modular 
wall panel. U.S. Pat. No. 4,989,438 to Simon discloses a hand operated 
power assisted punch and crimp for attaching comer bead to exterior comers 
in sheetrock or gypsum board walls. What is needed, and what the prior art 
lacks is a power assisted punch/crimping tool having the features of the 
present invention. 
SUMMARY OF THE INVENTION 
The present invention provides a power assisted crimping tool particularly 
suited to crimping and dimpling of structural steel decking and roofing 
panels together. The invention comprises a frame supporting a pair of jaws 
which are opened and closed by means of a toggle linkage having that is 
driven by an operator-controlled pneumatic cylinder. The input pivot of 
the toggle linkage is constrained to move linearly by means of a cross 
head formed in the frame, which, in turn causes the jaws to move in unison 
rather than one jaw moving against the other. According to one embodiment, 
the jaws are provided with a plurality of punch and die sets disposed in 
opposite orientations, such that as the decking or roofing panel joint is 
crimped by the jaws, the punch and die sets raise a plurality of dimples 
having alternating orientations. The alternating dimples provide a 
substantial increase in the lateral resistance (shear strenght) of the 
crimped seam, thereby obviating the need to additionally weld or screw the 
seam to provide the necessary shear strength.

DETAILED DESCRIPTION 
The drawing figures are intended to illustrate the general manner of 
construction and are not to scale. In the description and in the claims 
the terms left, right, front and back and the like are used for 
descriptive purposes. However, it is understood that the embodiment of the 
invention described herein is capable of operation in other orientations 
than is shown and the terms so used are only for the purpose of describing 
relative positions and are interchangeable under appropriate 
circumstances. 
The present invention relations to hand tools for forming crimp joints in 
structural steel decking and roofing commonly used in large commercial 
construction for example as subflooring for poured concrete floors or as 
roofing for large industrial buildings. As shown in FIG. 1, the individual 
decking or roofing panels are typically provided with one edge having an 
exposed upward "male" lip 4. The opposite edge is provided with an 
inverted "U" shaped female lip 6. The individual panels are typically 
joined together by placing the female lip over the male lip and welding, 
screwing or crimping the seam at periodic intervals. A prior art method of 
crimping the seam comprises use of a crimping tool known as the 601 SEAM 
LOCKER in which the user positions the jaws of the tool over the joint and 
by pulling the handles of the tool apart exerts a crimping force on the 
seam. 
Referring to FIGS. 2 and 3, an illustrative embodiment of the present 
invention comprises a tool 10 comprising a frame 12 having a handle 14 
adapted to be grasped by a user at about waist level so that the lower 
extreme of tool 10 is at about foot level. The central section 16 of frame 
12 comprises a rectangular frame constructed of hollow tubing which 
supports an upper extension 18, and a lower extension 20. Upper extension 
18 is constructed of a single piece of rectangular tubing welded to the 
upper surface 22 of central section 16, or alternatively, upper extension 
18 may be constructed of individual plates welded together to form a 
rectangular tube. Lower extension 20 is formed of two parallel plates 
welded to a spacer 24 which, in turn, is welded to central section 16. 
Referring to FIG. 2, a pneumatic cylinder 30 is attached to the upper edge 
28 of lower extension 20. Pneumatic cylinder 30 may comprise a piston 
inside a bore or other conventional pneumatically actuated linear motor. 
Preferably pneumatic cylinder 30 comprises a housing 32 which is divided 
into upper and lower chambers 34A and 34B by a diaphragm 36, which is 
crimped or otherwise sealed along the periphery of housing 32. The center 
portion of diaphragm 36 is covered by a piston plate 38, which acts as a 
rigid surface for the pressure in chamber 34A to act upon. In the 
illustrative embodiment, pneumatic cylinder exerts a force of 4,320 pounds 
at an inlet pressure of 100 psi with a maximum stroke of 23/4 inches, 
which corresponds to jaw movement of from an initial gap of 3/4 inch to a 
final gap of 1/16 for jaws having a 1 inch throat. Thus, when used in 
combination with the toggle linkage as described herein, the pneumatic 
cylinder provides the force and displacement necessary to crimp virtually 
all standard structural steel decking in a single-pass operation. 
Ram 40 is attached to piston plate 38 in order to convert the pressure 
action on piston plate 38 and diaphragm 36 into a force for actuating the 
jaw mechanism as hereinafter described. A return spring 42 acts against 
the pressure in chamber 34A to return the piston plate 38 to the upper 
limit of travel when pressure in chamber 34A is equal to the pressure in 
chamber 34B. 
The lower end of ram 40 terminates in a clevis 44 through which passes a 
clevis pin 46. In addition to passing through clevis 44, clevis pin 46 
passes through the upper ends 56, 58 of the input links 50 and 52 of a 
toggle linkage 60. The lower ends 62 and 64 of input links 50 and 52 are 
pivotally attached to the upper ends 66 and 68 of jaws 70 and 72. Jaws 70 
and 72 are pivotally attached to the lower end of lower extension 20 of 
frame 12 to open and close in response to the movement of toggle linkage 
60. A cross-head slot 48 is provided in lower extension 20. Cross head 
slot 48 engages clevis pin 46 to constrain clevis pin 46, which comprises 
the toggle input, to move linearly and therefore, constrains jaws 70 and 
72 to move in unison. 
A conventional air valve 100 housed within upper extension 18 regulates a 
source of pressurized air admitted through fitting 104 and provides a 
pressurized output into hose 106 for admittance into pneumatic cylinder 
30. An external valve handle 102 is provided for controlling air valve 100 
by the operator. Preferably, a bi-directional valve 120 is operatively 
disposed between air valve 100 and pneumatic cylinder 30 to admit 
pressurized air into pneumatic cylinder 30 when air valve 100 is open and 
to exhaust air from pneumatic cylinder 30 when air valve 100 is closed, 
thereby allowing pneumatic cylinder 30 to return to its upper limit of 
travel more rapidly, and thereby increasing the cycle rate of the 
apparatus. 
As shown more fully in FIG. 4, bi-directional valve 120 comprises a housing 
122 having an inlet 124, which is threaded to receive a standard hose or 
tube fitting, an outlet 126, which is threaded to form an airtight seal 
with the inlet 128 (FIG. 2) of pneumatic cylinder 30. Housing 122 further 
comprises an exhaust port 130. Valve seat 132 is formed on the inner 
surface of exhaust port 130. A flexible valve member 134 is constrained 
within chamber 136 of housing 122. As can be seen from FIG. 4, as high 
pressure air from air valve 100 enters through inlet 124, valve member 134 
is forced against valve seat 132 to close off exhaust port 130 and direct 
the flow of air through outlet 126 into pneumatic cylinder 30. Once air 
valve 100 is closed, air from pneumatic cylinder 30 begins to reverse 
direction and enter housing 122 through outlet 126. The reversed flow of 
air through outlet 126 causes valve member 134 to seat against surface 138 
thereby opening exhaust port 130 to permit relatively unobstructed exhaust 
of pressurized air from pneumatic cylinder 30. 
With reference to FIGS. 5 and 6, the jaws 70 and 72 are configured to move 
from an open position, in which the inner surfaces 78 and 80 define an 
angular opening, to a closed position in which surfaces 78 and 80 define a 
substantially parallel gap of predetermined thickness, based on the gauge 
of the decking being crimped. For example for 22 gauge decking, the closed 
position gap would be set to 1/16 inch. 
As shown in FIG. 6, jaw 70 is provided with a single punch 82. Punch 82 is 
preferably threaded into a corresponding threaded hole in jaw 70, which to 
permits adjustment of amount by which the exposed tip 84 of punch 82 is 
proud of the surface 78 of jaw 70. Similarly, jaw 72 is provided with two 
punches 86 and 88, which are offset to each lateral side (shown as above 
and below in the side view of FIG. 6) of punch 82. Jaw 72 is provided with 
dies in the form of indentations 90 and 92 which are juxtaposed from the 
tips of punches 86 and 88, respectively. Jaw 70 is similarly provided with 
an indentation 94, which is juxtaposed from the exposed tip 84 of punch 
82. Indentations preferably comprise semi-spherical or conical depressions 
drilled/milled in the surfaces 78 and 80 of jaws 70 and 72. Punches 82, 86 
and 88 comprise hardened threaded rods terminating in a conical or 
spherical tip as are common in the industry. 
In operation of a crimping apparatus in accordance with the present 
invention a user positions jaws 70 and 72 over the seam to be crimped and 
depresses the valve lever. High pressure air entering pneumatic cylinder 
30 causes ram 40 to be forced downward, exerting a force on clevis 44. 
Toggle linkage 60 actuated by the force on clevis 44 begins its motion 
from a first position as shown in FIGS. 2 and 3 in which the force 
multiplication of the toggle linkage is minimum. Toggle linkage 60 is then 
urged by ram 40 to a second position (not shown) in which the longitudinal 
axis of links 50 and 52 are collinear and the force multiplication of the 
toggle linkage theoretically approaches infinity. When used as a crimping 
tool for closing a male/female seam such as is found in structural steel 
decking, the toggle linkage employed in the illustrative embodiment 
provides an ideal force versus displacement curve. At the beginning of the 
stroke, the crimping tool must overcome only the elastic and then plastic 
bending resistance of the female lip of the decking along the longitudinal 
axis of the seam. Therefore less force multiplication is needed at the 
beginning of the stroke. As the seam closes, however, the crimping tool 
must plastically deform and upset the combined male and female sections, 
with concomitant increase in the force that must be applied. 
The toggle mechanism of the present invention provides the appropriate 
nonlinear force multiplication necessary to securely crimp the male and 
female deck sections together. Moreover, the unique staggered arrangement 
of punches 82, 86 and 88 and a depressions 90, 92 and 94 which cooperate 
to form three punch and die sets having alternating orientations, 
additionally plastically distort the crimped seam to form an arrangement 
of three dimples in a "Vee" pattern. The three dimples cooperate to 
prevent lateral shifting of the crimped joint, thereby obviating the need 
to additionally weld or screw the joint together. A distortion in the 
decking that would tend to open one of two outside dimples simply tends to 
tighten the remaining outside dimple, with the center dimple acting as a 
fulcrum. 
The force multiplication of a toggle linkage such as is used in the present 
invention is highly sensitive to the beginning and ending gap of the jaws 
70 and 72. As pivots wear through use, the toggle linkage may begin to go 
over center before the crimping operation is complete or particularly 
where lighter gauge metal is used, the crimp may be complete before the 
linkage approaches its maximum force multiplication, thereby reducing the 
efficiency of the stroke. Accordingly, means is provided to permit both 
the input stroke to clevis 44 to be adjusted as well as the linkage ratio 
of the toggle linkage itself. The input stroke is adjustable by means of a 
threaded engagement 140 between ram 40 and clevis 44. Similarly the 
linkage ratio of the toggle linkage 60 is adjustable by means of a 
threaded engagement 144 between an upper half 144 and a lower half 146 of 
link 52. Manipulation of the aforementioned adjustments permits the input 
stroke to be regulated to prevent the toggle linkage 60 from going over 
center, which could lead to the mechanism becoming jammed, and permits the 
linkage ratio of the toggle linkage 60 to be adjusted to provide a 
predetermined gap between the inner surfaces 78 and 80 of jaws 70 and 72 
when the toggle linkage 60 is in the on-center position with the axis of 
links 50 and 52 collinear. The predetermined gap can be adjusted to 
accommodate the specified crimp thickness of a wide range of standard 
structural steel decking and roofing panels. 
Although certain preferred embodiments and methods have been disclosed 
herein, it will be apparent from the foregoing disclosure to those skilled 
in the art that variations and modifications of such embodiments and 
methods may be made without departing from the spirit and scope of the 
invention. Accordingly, it is intended that the invention shall be limited 
only to the extent required by the appended claims and the rules and 
principles of applicable law.