Cam locking pin

A cam locking pin for temporarily securing together a pair of members such as plates having confronted faces and aligned apertures. The pin is inserted through the apertures, as from below. A pawl member at the upper end of the position is pivoted ninety degrees to a position in which its long dimension lies crosswise of the pin and apertures and that dimension is greater than the diameter of the pin so that the pin cannot fall out of the apertures. A lower portion of the pin depends below the bottom plate and has a stud or lug thereon for receiving a swingable tool having cam or eccentric surfaces acting against the lower plate to draw the plates together. The cam is so shaped as to retain its locking position until released.

BACKGROUND OF THE INVENTION 
Many devices have been provided over the recent past for locking together a 
pair of members for securing them in a temporarily selected position. The 
commonest of these, of course, is the conventional nut and bolt, the 
disadvantages of which are that the parts may become lost, a wrench is 
required to tighten the nut and considerable manual effort must be 
expended. Other types of devices include headed pins with some form of 
wedge means driven through a slot in the unheaded end of the pin. Here 
again the parts are separable and are subject to loss. 
The present invention is directed especially to instances involving 
relative heavy steel structures; e.g., one including a base or bed over 
which a second structure may be moved, as about a pivot. In an instance in 
which the pivoted member lies below the base, some amount of sag will be 
present, and this must be eliminated when the base and bed are locked 
together. It often occurs that one or the other of the members will 
include a channel member in the area in which locking must take place, 
making it difficult if not impossible to insert a headed pin from above 
and likewise rendering it disadvantageous to insert the pin from below 
while attempting to insert a wedge or the like from above. 
According to the present invention, these and other problems are eliminated 
by the provision of a pin having at its upper end a recess, preferably in 
the form of a slot that opens axially as well as diametrically of the pin. 
A pawl member is carried in the slot on a pin crosswise of the slot and 
the pawl is so shaped as to have a long dimension greater than the 
diameter of the pin and a short dimension at least not substantially 
greater than the pin diameter. The slot has such depth that, when the pawl 
is positioned with its long dimension in prolongation of the pin, the pin 
may be inserted through alined apertures from below, after which the pawl 
is turned ninety degrees so that the pawl spans the upper aperture and 
prevents the pin from falling out. The lower end of the pin has lug means 
there that will be spaced below the lower member. A tool is provided for 
wedging action between the lug means and the lower member for forcing the 
lower member tightly upwardly into face-to-face contact with the upper 
member, thus securing the two members rigidly together. The tool is in the 
form of a lever having a bifurcated end providing interior hooks for 
engagement with the diametrically projecting lug means and exterior cam 
surfaces for creating the wedging action.

DETAILED DESCRIPTION OF THE INVENTION 
In FIG. 1, the numeral 10 designates a base or bed made up for example of 
steel plates, and below it is a lower plate-like member 12. As noted, 
there is a gap or space 14 between the confronting surfaces of the 
members. The cam locking pin is designated in its entirety at 16 and it is 
the function of this device to draw the members tightly together as in 
FIG. 2. 
The locking device includes a pin-like element 18 of cylindrical cross 
section having upper and lower ends 20 and 22, respectively (FIG. 6). The 
length of the pin is such that its upper and lower ends will extend 
respectively above and below the upper and lower members. Here, as 
elsewhere in this description, the use of such expressions as "upper", 
"lower", etc., is resorted to in the interests of clarity and convenience. 
Obviously the parts may be otherwise oriented. The lower projecting end of 
the pin has a pair of diametrically oppositely projecting lug means 24, 
preferably a hardened steel pin inserted via a force-fit through an 
appropriate hole (not shown as such) in the similarly hardened steel pin 
18. The upwardly projecting top end of the pin 18 has a recess or pocket 
therein in the form here of a slot 26 opening axially as well as 
diametrically of the pin to bifurcate the end 20 and thus provide a pair 
of leg means 28. 
A pawl member 30 has a central aperture 32 which lines up with cross holes 
34 in the pin 18 when the pawl is received in the slot. A suitable pivot 
pin 36 (FIGS. 1 and 2) is passed through the aligned holes to mount the 
pawl on a pivot axis crosswise of the slot and diametrically of the pin 
18. As will be noted, the long dimension of the pawl is considerable 
greater than the diameter of the pin 18 and its short dimension is at 
least not substantially greater than the pin diameter. The depth of the 
slot 20 below the pivot pin 36 is such as to receive one end of the pawl 
member when that member is turned to the position of FIG. 4, which is in 
effect a prolongation of the pin 18. This enables upward insertion of the 
upper end of the pin 18 and pawl through holes 38 and 40 in the upper and 
lower members 10 and 12 respectively. After the pin is so inserted, the 
pawl member is rotated ninety degrees to the position shown in FIGS. 1, 2 
and 6. It will also be noted that the combined thickness of the pawl and 
leg means 28 is about the same as the diameter of the pin 18. 
At this stage, the lower end of the pin projects below the lower member 12 
and the diametrically oppositely projecting lug means are spaced below 
that member. The lug means can have this amount of projection because of 
the ability of the pin 18 to be inserted pawl end first through the member 
apertures 38 and 40. The insertion could be reversed of course, the 
present illustration being based on a situation where surrounding 
structure (not shown) would prevent insertion of the pin from above. The 
means for drawing the members 10 and 12 tightly together here includes a 
tool 42 having a handle 44 to which a pair of hook-like plate elements 46 
are rigidly affixed (as by welding). These elements give the handle or 
tool a bifurcated end and each furcation or plate element has an interior 
hook 48 for hooking over one of the lug means 24, starting with the 
position of FIG. 1. Each furcation has an exterior cam or eccentric 50 
formed on an arc of increasing radius relative to the axis of the lug 
means. Thus when the tool is rotated counter-clockwise from the position 
of FIG. 1 to that of FIG. 2, the cams act as wedge means against the under 
face of the lower member 12 and, since the cross-wise pawl engages the top 
of the upper member 10, the two members are drawn tightly together. Each 
cam 50 leads to a flat 52 which functions to hold the tool in its locked 
position (FIG. 2) until manually released. 
Among the features of the invention are these: it is easy and positive to 
operate; the pivoted pawl prevents loss of the pawl; the combined pin and 
pawl are large enough to be easily handled and not likely to become 
misplaced; the tool is likewise easy to handle and not likely to become 
misplaced; the several parts of the structure are simple and quite easy to 
manufacture. Features other than those enumerated will readily occur to 
those versed in the art, as will many modifications in the preferred 
embodiment of the invention disclosed herein.