Pallet registry system

A multiple station transfer machine in which workpieces are located and supported in pallets and transferred sequentially through said machine and precisely located in each station along the transfer line, a three point locating system in which each pallet is located in one direction at spaced pressure points by a force applied in the direction of and midway between said points. The force application is applied by complemental wedge surfaces which can shift the pallet to cause it to meet the spaced pressure points, after which the pallet is clamped. A sequential actuator first locates and then clamps the pallet into a registry position. Slide rails for lineal transfer of the pallets are arranged to shift vertically relative to other supports for the pallets at each station, so the rails may be shifted to a non-interferring position prior to a clamping sequence so variations in slide rail dimensions due to wear and other influences will not affect the vertical registry of the clamped pallets.

FIELD OF INVENTION 
Automation equipment utilizing work carrying pallets and locating devices 
for insuring accurate pallet location as each pallet comes to rest at a 
work station. 
REFERENCE TO COPENDING APPLICATION 
Reference is made to my copending applications, Ser. No. 950,318, filed 
Oct. 11, 1978, on a Pallet Registry System, and Ser. No. 918,528, filed 
June 23, 1978, on a Work Clamp and Pallet Combination. 
BACKGROUND AND OBJECTS OF THE INVENTION 
In some types of automatic workpiece processing, the workpieces are located 
and clamped in movable fixtures known as pallets, which are progressively 
transferred from station to station of a multiple station transfer 
machine. In each station of such a multiple station machine, these pallets 
are located as accurately as possible and clamped by a mechanism referred 
to as a pallet registry. Once located, a machine adjacent the pallet 
performs a milling or drilling or other operation on the workpiece. The 
accuracy of the resultant operation is only as accurate as the location of 
the pallet and workpiece. 
A wide variety of types of registries have been in use in the industry for 
many years. Several such registry mechanisms are shown in U.S. Pat. Nos. 
2,672,675; 2,673,386; 3,155,217; 3,571,872; 3,968,869 and my copending 
application, Ser. No. 950,318, filed Oct. 11, 1978. The location of a 
pallet with respect to a registry is generally accomplished with a pair of 
locating pins, vertically movable in the registry, which engage 
corresponding holes in each pallet. Slight errors of pallet location are 
inevitable because of the practical working clearances required between 
the locating pins and their guide sleeves in the registry frame, and 
between the locating pins and the corresponding holes in the pallet. These 
slight errors become progressively larger with usage due to pin, guide 
sleeve, and pallet hole wear. 
It is one object of this invention to provide a pallet registry which is 
free of these initial working clearance type errors associated with 
locating pins, and, further to provide a pallet registry in which the 
location errors due to wear are significantly reduced. 
It is often times convenient to rotate to pallet 90.degree. about a 
vertical axis at some intermediate station as a pallet moves through the 
machine. This is generally done to bring otherwise inaccessible workpiece 
surfaces into position for processing by working stations which are 
disposed along either side of the line of pallet travel. 
It is another object of this invention to provide a pallet registry and 
pallet combination which is capable of precisely locating a pallet with 
respect to the registry in any one of four attitudes of the pallet which 
are created by rotation of the pallet in 90.degree. increments about a 
vertical centerline. 
The movement of pallets through a transfer machine is presently 
accomplished in one of two ways; they can be slid from station to station 
on fixed rails driven by a horizontally reciprocating transfer bar which 
selectively engages all pallets to move them in the forward direction, and 
is disengaged from the pallets during its return travel; or the pallets ca 
be moved by a "lift and carry" mechanism from station to station by first 
being lifted by a set of transfer bars in a substantially vertical 
direction, then being moved forward with the transfer bars through a 
horizontal stroke equal to the station spacing, and finally being lowered 
by the transfer bars in a substantially vertical direction. The first 
slide system of pallet transferring requires only a simple reciprocating 
transfer bar and slide rails but has the disadvantage of locating the 
pallets along the vertical axis from the rails on which the sliding occurs 
and through the pallet feet which slide on the rails. Both the rails and 
pallet feet are very subject to wear, especially where dirt, dust and grit 
can accumulate on the rails, and this combined wear directly affects the 
accuracy of vertical pallet location. The lift and carry pallet transfer 
system eliminates the vertical location error problem due to wear, but at 
the expense of incorporating a more complex lift and carry type transfer 
system for the pallets. 
It is another object of this invention to provide a pallet registry which 
combines the simplicity of moving the pallets on slide rails using a 
reciprocating transfer bar, but vertically locating the pallet in the 
registry on surfaces not subject to sliding wear. 
Other objects of this invention are to provide registries which may be 
grouped together to be operated by a single power source; to provide 
registries in which the clamps have a significantly greater movement range 
than those of present designs, to provide registries which do not utilize 
screws, wedges, or other low efficiency mechanisms in generating the 
clamping force, and to provide registries in which the bending loads due 
to clamping are primarily confined to members whose deflection does not 
affect the accuracy of pallet location, and in which the bending loads 
imposed on the locating and structural components of the registry are 
minimized to achieve lower deflections per unit of clamping force. 
Other objects of this invention will be apparent in the following 
description and claims with the accompanying drawings in which there is 
disclosed the principles of operation of the invention and the best mode 
presently contemplated for the practice thereof.

In the aforesaid copending application in which is described a locating pin 
type pallet registry, the efficiency of a mechanism was defined as the 
ratio of the work (force times distance) output from the mechanism to the 
work input to the mechanism. High efficiency mechanisms, those having an 
efficiency of 85% or more, are pivots, levers, gears and rolling contact 
mechanisms; low efficiency mechanisms, those having an efficiency of less 
than 85% are screws and wedges. The loss of efficiency of a mechanism is 
due to the frictional losses therein. The efficiency of a mechanism was 
also shown to be the ratio of the output force with normal friction to the 
output force of that same mechanism with zero friction, for some fixed 
input force. These same considerations also apply to the invention 
disclosed herein. 
In the accepted classical sense, every body has six degrees of freedom in 
space; three degrees of freedom in translation along the X, Y, and Z axes, 
and three degrees of freedom in rotation about the X, Y, and Z axes. In 
the location system described herein the locators which support the pallet 
vertically, which is along the Z axis, determine its position, in 
translation, along the Z axis; they also determine its angular position in 
rotation about the X axis and about the Y axis. These vertical support 
locators therefore lock these three degrees of freedom. The locking of the 
remaining three degrees of freedom, translation position along the X axis, 
translation position along the Y axis, and angular position about the Z 
axis (in the X-Y plane) will be described. 
In the location of a pallet, or indeed any movable object with respect to a 
fixed system, certain fundamental considerations arise. The use of pins to 
locate a pallet, though commonly practiced, leads to small errors due to 
the required working clearances between the pin and its guide sleeve and 
between the pin and its mating hole in the pallet. A location system in 
which these inherent errors are eliminated is much to be preferred for 
high precision location. One such technique, using two fixed locators and 
one moving locator, is shown schematically in FIG. 1. A square pallet 
frame 2 is clamped against two fixed locating surfaces 4 by a wedge 6 or 
its functional equivalent guided by means to be subsequently shown which 
permit no lost motion. 
The process of achieving the final location will now be analyzed. FIG. 2 
shows this same pallet 2 which has been brought into the station by the 
transfer system while the locating wedge 6 is retracted. The errors of 
pallet location after it has been delivered by the transfer system are 
greatly exaggerated for clarity and to illustrate the location process. 
Even though the actual errors are significantly smaller, the locating 
behavior of the system remains the same. It will be noted that the total 
error between the pallet position relative to its final desired position 
is comprised of three components; an error in the X position of the pallet 
along the line of transfer; an error in the Y position of the pallet 
transverse to the line of transfer; and an error in the angular position 
of the pallet in the X-Y plane. 
The wedge 6 is then moved inward along the Y axis by some external means 
until it is stopped by the pallet 2; i.e., its stroke is not to a fixed 
position, but to a fixed force. The wedge 6 movement is substantially 
continuous, but will be shown in discreet internals to illustrate the 
sequential events that occur during the overall locating process. 
In FIG. 3, the wedge 6 has contacted the pallet 2 and pushed it over until 
it has contacted one of the locators 4, and the wedge has fully seated 
itself in the notch of the pallet 2. This step of the location process is 
straightforward and easily seen. From this position onward a very critical 
force and movement situation exists. Under what conditions does a 
continued inward movement of the wedge 6 cause the pallet to achieve the 
final located position shown in FIG. 1?. 
A free body diagram of the pallet 2 illustrating all the forces on it is 
shown in FIG. 4. F.sub.W is the axial force on the wedge 6 and can be made 
arbitrarily large. F.sub.R is the reactive force on the pallet from the 
contacting locator 4. F.sub.F is the tangential force on the pallet 2 from 
the contacting locator 4 due to the friction at this interface; and 
F.sub.T is the induced force from the wedge 6 to the pallet 2 required to 
offset F.sub.F. 
Two other sets of forces are intentionally ignored in this analysis for 
simplicity. Because the accelerations are relatively small, forces 
required to create them are ignored, but their inclusion in the analysis 
would work against the locating forces. Furthermore, the frictional forces 
on the pallet due to its sliding on the surfaces which support its weight 
are also ignored, because to include them would require specific knowledge 
of the weight of the pallet relative to the magnitude of the locating 
force F.sub.W ; for the purposes of the analysis F.sub.W is assumed to be 
much larger than the support surface frictional forces, which are 
temporarily ignored. 
Referring to FIG. 4 and with the aforesaid simplifications in mind, it can 
be seen that: 
EQU F.sub.R =F.sub.W (1) 
EQU F.sub.F =F.sub.T (2) 
and if the coefficient of friction at the contacting locator 4 is given by 
.mu. then: 
EQU F.sub.F =.mu.F.sub.R (3) 
It can be seen that in order to move the pallet 2 to its final desired 
locating position, a clockwise moment M.sub.C must be applied to cause the 
required clockwise movement. Referring to FIG. 4, S.sub.1 is the distance 
across the width of the locating portion of the pallet 2, and S.sub.2 is 
the locating span between the fixed locators 4. 
The clockwise moment M.sub.C is given by: 
EQU M.sub.C =F.sub.R S.sub.2 /2-S.sub.1 F.sub.F 
Substituting from equation (3) 
EQU M.sub.C =F.sub.R S.sub.2 /2-S.sub.1 .mu.F.sub.R 
EQU M.sub.C =F.sub.R (S.sub.2 /2-S.sub.1 .mu.) 
Since F.sub.R =F.sub.W 
EQU M.sub.C =F.sub.W (S.sub.2 /2-S.sub.1 .mu.) (4) 
From equation 4, it can be seen that for M.sub.C to have a positive value 
EQU S.sub.2 /2&gt;S.sub.1 .mu. 
EQU S.sub.2 /S.sub.1 &gt;2.mu. 
Therefore, in order for a force F.sub.W to cause the pallet 2 to locate, 
the ratio S.sub.2 /S.sub.1 must be at least double the coefficient of 
friction at the locator 4 to pallet 2 interface. Since the retarding 
friction of the support surfaces was omitted for simplicity of analysis, 
and since it also always detracts from the correcting couple, which, in 
this case, is shown as being clockwise, it follows that S.sub.2 /S.sub.1 
must be even greater than 2.mu.. Indeed, the larger the quantity S.sub.2 
/S.sub.1, the greater the correcting couple applied to the pallet 2 for 
any given value of wedge force F.sub.W. The quantity S.sub.2 /S.sub.1 will 
be termed the Locating Ratio, and, as shown by the previous analysis, the 
larger its value, the more easily is the pallet 2 moved from the position 
shown in FIG. 4 to its final located position shown in FIG. 1. This 
condition is further corroborated by reference to FIG. 5 and FIG. 6. In 
FIG. 5, the pallet 2 is configured to have a Locating Ratio of 1/4 and it 
can be intuitively seen that the force F.sub.W cannot cause the pallet 2 
to move to the desired located position 2a, shown dotted. On the other 
hand, in FIG. 6, the pallet 2 is configured to have a Locating Ratio of 4, 
and it can be seen that this situation makes it relatively easy for a 
force F.sub.W to move the pallet to the desired located position 2a. 
For dependable locating, it is desirable to have the ratio S.sub.2 /S.sub.1 
greater than 2, when the temporarily ignored frictional resistance to 
movement caused by the weight of the pallet on the support surfaces is 
taken into account, and even larger values are more desirable. It can be 
seen in FIG. 6, or in FIG. 1, that when the pallet 2 is clamped against 
the fixed locators 4, its translational position along the Y axis and its 
angular position about the Z axis are both locked, and its translational 
position along the X axis is locked by the shape of the wedge 6 in its 
corresponding seat in pallet 2. 
In the foregoing analysis, it was assumed that the pallet was mislocated in 
such a way that a clockwise correcting couple and clockwise movement was 
required to bring it to the desired final location. A similar analysis can 
be made to show that the same effects are noted if the initial location of 
the pallet 2 is such that a counterclockwise correcting movement is 
required to achieve the final located position. As will be seen in the 
invention to be described, the utilization of a very large Locating Ratio 
was a primary objective. 
It was noted earlier that the motion of the wedge 6 must be through a 
system in which there is no lost motion between the wedge and its side 
guiding system. One very simple way this can be accomplished is by using a 
floating tapered double wedge or cone which operates between an accurately 
fixed reference locator mounted on the registry and a similar locator 
mounted on the pallet. Such a system is shown in FIGS. 7, 8 and 9. 
FIG. 7 is an end view of a locating system, viewed along the line of pallet 
travel, which is the functional equivalent of the wedge system illustrated 
in FIGS. 1 to 6. A reference locator 12 is mounted to a registry frame 14 
and a pallet locator 16 is mounted to the underside of a pallet 18. As can 
be seen from the sectional plan view, FIG. 8, locator 12 has cut into it 
two faces or planes 20 and 22; these faces 20 and 22 from a V when cut by 
any horizontal plane such as the sectioning plane of FIG. 8. Additionally, 
each of the faces 20 and 22 are inclined with respect to a vertical axis 
A.sub.2. 
Two faces or surfaces 24 and 26 are also cut into the pallet locator 16. 
These faces 24 and 26 also form a V when cut by any horizontal plane such 
as the sectioning plane of FIG. 8; and each of the faces 24 and 26 are 
also inclined with respect to the vertical axis A.sub.2 at angles which 
are identical with the vertical inclination angles of faces 20 and 22 on 
the reference locator 12. When the pallet locator 16 is properly 
positioned with respect to the reference locator 12, the planes of the 
four faces 20, 22, 24 and 26 intersect at a common theoretical apex point. 
Stated another way, the four faces 20, 22, 24 and 26 comprises sectors of 
the faces of a four sided pyramid. This condition is created through the 
use of a floating conical locator 28 which is moved along a substantially 
vertical axis for the most part coincident with A.sub.2, which is at right 
angles to the plane of movement of the pallet locator 16. Therefore, when 
the final positioning of pallet locator 16 is achieved, the conical 
locator 28 is in simultaneous line contact with each of the four faces 20, 
22, 24 and 26. 
The combination of the theoretical locating techniques illustrated in FIGS. 
1-6 and in FIGS. 7-9 is shown in FIG. 10, a plan view schematic of the 
total locating system. It is assumed that the pallet 2 is suitably 
supported with feet resting on support surfaces which support it on the Z, 
or vertical axis, perpendicular to the X-Y plane. The position of the 
pallet 2 along the Y axis is determined by the fixed locators 4, and the 
position of the pallet 2 along the X axis is determined by having the 
conical locator 28 simultaneously in contact with the faces 24 and 26 on 
the pallet locator 16 and with the faces 20 and 22 on the fixed locator 
20. 
It is assumed that when the pallet 2 is brought into the station in which 
the pallet is to be located, a small and unequal clearance exists between 
the fixed locators 4 and the corresponding surface of the pallet 2; it is 
further assumed that the pallet is slightly mispositioned along the X 
axis. It will be noted that the Locating Ratio, as previously defined, is 
in excess of 4 to 1. The entire locating sequence is created by the upward 
vertical movement of the conical locator 28 which is driven by a suitable 
mechanism to be described. It is also assumed that the total mislocation 
of the pallet 2 with respect to the reference locator 12 is sufficiently 
small to permit the smallest diameter of the conical locator 28 to enter 
the interspace defined by the faces 20, 22, 24 and 26. During its upward 
travel, the conical locator 28 will generally first contact face 24 or 26 
of the pallet locator 26. Since the conical locator 28 is resiliently 
mounted on its operating mechanism, it will be displaced until it contacts 
the face 20 or 22 of the fixed locator 12. Unless the pallet 2 has, by 
happenstance, been perfectly located in the "X" direction, the contact 
lines between the conical locator 28 will be diametrically opposite; i.e., 
the conical locator 28 will contact faces 20 and 24 or faces 22 and 26, 
depending on the position error of the pallet 2 in the X direction. 
As the conical locator is moved upward in contact with either of two 
diametrically opposite face pairs, two locating processes occur. These two 
processes may occur simultaneously or sequentially, and, if sequentially, 
in one order or the other. 
In one process, the upward moving conical locator 28 causes the pallet 
locator 16 to move away from the fixed locator 12 along the Y axis. This 
causes the pallet 2 to move away from the locator 12 until the pallet 2 
contacts and is located by the two fixed locators 4, insofar as its Y axis 
position is established. This process may occur in two discreet steps: a 
first step in which the pallet 2 moves in translation until it contacts 
one or the other of the two locators 4 and a second step in which it moves 
in rotation until it contacts the other locator 4. In any case, one 
process caused by the upward movement of conical locator 28 is the 
location of the pallet 2 by both fixed locators 4. 
The second process caused by the upward moving conical locator 28 is the 
proper positioning of the pallet 2 along the X axis. If, at the end of the 
first location process, the pallet is properly positioned along the X 
axis, the conical locator 28 will contact all four faces 20, 22, 24 and 26 
simultaneously and any further upward movement is prevented. If, at the 
end of the first location process, the pallet 2 is not properly located 
along the X axis, one of two conditions exists; the pallet 2 is too far to 
the right or too far to the left as viewed in FIG. 10. If it is assumed 
that the pallet 2 is too far to the right, the condition between the fixed 
locator 12 and the pallet locator 16 will be as shown in FIG. 11. With the 
condition so drawn, it can be seen that the upward movement of the conical 
locator 28, forces a separation of face 24 on the pallet locator 16 from 
face 20 on the fixed locator 12. This forces the locator 16 to move to the 
left with respect to the fixed locator 12, moving the pallet 2 to the left 
also. Such movement of the locator 16 and pallet 2 to the left continues 
as a result of the upward movement of the conical locator 28, until the 
conical locator 28 also makes contact with the faces 22 and 26, at which 
point further upward movement of the conical locator 28 is prevented. 
If it is assumed that the pallet 2 was originally mislocated to the left 
along the X axis, the conical locator 28 makes initial contact with faces 
22 and 26 driving the pallet locator 16 to the right until it also makes 
contact with faces 20 and 24, at which point further upward movement of 
the conical locator 28 is again prevented. 
It can be seen that in this second correction process, there is a tendency 
for the conical locator 28 to roll between the two surfaces with which it 
is in contact, which is desirable, since it tends to distribute the wear 
around the conical peripheral surface in a random manner. 
In summary, the upward movement of the conical locator 28 causes the pallet 
2 to be forced against the fixed locators 4 by a translation along the Y 
axis and by a rotation about the Z axis normal to the X-Y plane, and 
simultaneously or sequentially to move the pallet along the X axis until 
the conical locator is in simultaneous contact with the faces 20 and 22 on 
the fixed locator 12 and faces 24 and 26 on the pallet locator 16. 
It will be noted that wear on the faces of the fixed locators 4 and the 
corresponding surfaces on the pallet 2 is minimized because the sliding 
movements encountered by these surfaces are only the X axis error 
correction movements, which are very small, and because the contact 
surfaces are area rather than line contacts. Furthermore, the forces these 
surfaces must react are small until the movement along the X axis is 
stopped. 
In FIGS. 7 and 8, the wear on the faces 20, 22, 24 and 26 and on the 
conical locator 28 will be larger because only line contact is used; the 
effect of such wear on locating accuracy must be evaluated in terms of the 
specific angles of the faces 20, 22, 24 and 26 as arbitrarily measured 
from the Y axis. 
Referring to FIG. 8, it can be seen that these angles are shown as being 
identical; this need not be the case. Indeed, all four angles could be 
different and there would still exist only one position of locator 16 
along the X axis (the Y axis positioned being determined by locators 4) in 
which the conical locator 28 could be simultaneously mutually tangent to 
all four faces 20, 22, 24 and 26. However, with such non-identical angles, 
an assumed uniform wear on each face could result in a slight shift in the 
X position of locator 16 when simultaneous mutual tangency to conical 
locator 28 is reached. In order to eliminate this X position-shift due to 
assumed uniform wear, it is only necessary that the angles made by faces 
24 and 26 with respect to the Y axis be identical and opposite to each 
other; and that the angles made by faces 20 and 22 with respect to the Y 
axis also be identical and opposite to each other. It is not necessary 
that the angles made by faces 24 and 26 with respect to the Y axis be the 
same as the angles made by faces 20 and 22 with respect to the Y axis. If 
these pairs of angles are different, the assumed uniform wear would not 
cause a shift in the X position of locator 16 but would cause a shift of 
the Y axis position of the conical locator 28 to achieve simultaneous 
mutual tangency with all four faces, which can be accommodated if the 
conical locator 28 is permitted to float with respect to its actuating 
mechanism, and move upward as needed. 
The natural random rolling tendency of the conical locator 28, it its 
mounting permits this, will tend to distribute the wear uniformly around 
its periphery; such uniform wear is not harmful since it remains a cone 
and will only move further upward to achieve simultaneous mutual tangency 
with faces 20, 22, 24 and 26, provided its driving mechanism is capable 
thereof. 
Summarizing, location accuracy need not be impaired due to wear if the 
faces 24 and 26 are equally and oppositely inclined to the Y axis, and if 
the faces 20 and 22 are also equally and oppositely inclined to the Y 
axis. If is also clear that the location of the pallet 2 does not depend 
on direct control of the axis of the conical locator 28; indeed, it is 
necessary that this conical locator 28 be permitted to find its own 
position between the four faces 20, 22, 24 and 26. Accordingly, the 
optimum mounting situation for the conical locator 28 is to have it float 
with respect to its supporting mechanism. 
The location system, the theory of which has been outlined above, together 
with other improvements, is employed in the pallet registry mechanism 
described below. 
FIG. 12 is a plan view of a pallet registry assembly, on which are 
superimposed four pallet feet 40 mounted on the pallet base 42, shown in 
plan view outline. Also mounted on the pallet base 42 are four blocks 44 
which are engaged by fingers 46 on a transfer bar 48. The pallet 42 is 
moved from station to station by lineal motion of the transfer bar 48 
through the fingers 46, when in position 46a (FIG. 13), in engagement with 
one of the blocks 44; before its return stroke, the transfer bar 48 is 
rotated about its own axis, disengaging the fingers 46 from the block 44, 
and the transfer bar 48 returns without moving the pallets with it. Four 
blocks 44 are provided on the pallet base 42 so that the pallet base 42 
may be engaged by the transfer bar in any one of four positions of the 
pallet base 42 as will be explained. A pallet locator 50, having four 
sided symmetry, is also mounted to the pallet base 42, to cooperate with 
the registry location system. 
Referring also to FIG. 13, a complete registry is made up of a primary 
housing 54 and a secondary housing 56, which optionally may be 
interconnected with an integral tie bar 58 shown dotted in FIGS. 12 and 
13. With the tie bars 58 present, the registry housing becomes a single 
unit which is advantageous in increasing the rigidity; however, with the 
tie bars 58 absent, the registry is separated into two halves each of 
which may be removed from or replaced on the machine bed without removing 
the transfer bar. 
An interrelated locating system and clamping system is associated with the 
primary housing 54, while a clamping system only is associated with the 
secondary housing 56. 
Referring to the longitudinal sectional drawing (FIG. 14), a master 
bellcrank 60 is fastened to a torque tube 62 journalled on a shaft 64 
mounted in the housing 54. This bellcrank 60 is actuated by an external 
push rod 66, driven by an external power system which drives multiple push 
rods 66 actuating a series of registries mounted along the machine. The 
other arm of the bellcrank 60 is connected through a wear rod 68 to a 
nosepiece 70 of a spring cartridge 72. The spring cartridge 72 is 
comprised of a mounting bracket 74 which loosely guides a tension rod 76, 
which at one end is connected to the nosepiece 70 and at its other end 
mounts a spring seat 78. A coil compression spring 80 is preloaded and 
mounted between the bracket 74 and the spring seat 78. With the spring 
cartridge 72 not assembled into the registry, it can be seen that the 
travel of the spring 80 is limited by the contact between nosepiece 70 and 
mounting bracket 74. It is, therefore, possible, through the use of an 
external preload fixture, to precompress the spring 80 before fastening 
the nosepiece 70 or spring seat 78 to the tension rod 76. 
It can be seen that the spring cartridge 72 exerts a clockwise torque on 
the bellcrank 60, while an upward movement of the push rod 66 causes a 
counterclockwise movement of the bellcrank 60; and this in turn causes the 
tension rod 76 to move to the left further compressing the spring 80. The 
bellcrank 60 is shown in FIG. 14 in its most clockwise position, at which 
point the registry has lowered, located and clamped a pallet, as will be 
explained. When the push rod 66 is raised by external means, the bellcrank 
60 is positively driven in a counterclockwise direction through an angle 
of approximately 30.degree. which unclamps and raises the pallet 42, and 
disengages the locating system; it also delivers energy or work into the 
cartridge 72. As the push rod 66 is lowered by external means, the 
bellcrank 60 is rotated clockwise by the spring cartridge 72 lowering, 
locating and clamping the pallet 42 through the work output of spring 80. 
Each registry can therefore adapt to the various dimensional variations in 
the clamp system to achieve full clamp pressure. The bellcrank 60 
transmits its angular motion to the torque tube 62 which is the common 
actuator element for the lowering, locating and clamp systems. 
The clamping system is shown in the longitudinal section (FIG. 15) and the 
transverse section (FIG. 13). The torque tube 62 has mounted to it a drive 
arm 82 in whose outboard end is formed an elongated slot 84. An 
intermediate link 86 is mounted on a shaft 88 journalled in the frame 54; 
the outboard end of the link 86 has mounted on it a coupling pin 90 which 
operates in the slot 84 in arm 82. A tie link 92 is pivotally connected to 
the link 86 by a pin 94; at its other end, the tie link 92 is pivotally 
connected to an equalizer link 96 by a pin 98; this connection to link 96 
is at or near its midpoint. At its two ends, the equalizer link is 
connected to clamp levers 100 and 102 by pins 104 and 106 respectively. 
The two clamp levers are symmetrically opposite and each operates one of 
the two clamps. 
The clamp lever 100, at its other end, has mounted on it a cylindrical 
insert 108 which rolls on a reaction pad 110 mounted in the housing 54. 
This slightly moving connection between the insert 108 and the reaction 
pad 110 is the fulcrum axis for the lever 100 and is noted as axis 
A.sub.3. On the other side of the lever 100 is mounted a cylindrical 
insert 112 having a center on the clamp axis A.sub.4. This insert 112 
bears against the mating concave face of a shoe 114; the opposite face of 
shoe 114 has a convex cylindrical face which mates with a concave face of 
the clamp member 116. This clamp member 116 has a "C" configuration, FIG. 
13, with a substantially straight cylindrical body having an extended 
integral lower section which mates with shoe 114 and an extended integral 
upper section with a clamp face 118 which bears against the upper surface 
of the pallet foot 40 during clamping. The pallet foot 40, during 
clamping, is supported by locator pad 120 mounted on the housing 54. The 
cylindrical body of the clamp member 116 is guided in an elastomeric 
bushing 122, such as neoprene or urethane, mounted in the housing 54. The 
lower end of the clamp member 116 rests on an elastomeric pad 124, which 
functions as the clamp return element. The clamping components associated 
with the symmetrically opposite clamp lever 102 are identical with those 
associated with the clamp level 100 as described above. 
It will be recalled that the clamps are actuated by a clockwise rotation of 
the torque tube 62; this causes the arm 82 to rotate clockwise which in 
turn causes pin 90 and 94 on link 86 to move downward. This movement is 
transmitted to the equalizer link 96 by tie link 92. It will be noted that 
the equalizer link 96 transmits this movement through pins 104 and 106 to 
clamp levers 100 and 102 respectively, and provides an equal force to 
these clamp levers 100 and 102. The clamp lever 100 rotates clockwise 
about the fulcrum axis A.sub.1, and, through the shoe 114 forces the clamp 
member 116 downward, compressing the elastomeric pad 124 and closing the 
clearance between the upper surface of pallet foot 40 and clamp face 118. 
The clamp lever 102 rotates counterclockwise and actuates the clamp member 
116 associated with it downward in an identical fashion. When both clamp 
members 116 are exerting their clamp force against the two pallet feet 40, 
the rotation of the torque tube 62 is stopped, although a clockwise torque 
is still being applied to the torque tube 62 by the spring cartridge 72. 
The clamp system is in equilibrium between the force of the spring 
cartridge 72 and the reactive force of the pallet feet back to the faces 
118 of the clamp members 116. A highly reproducible clamping force is 
thereby attained. When this equilibrium condition is achieved, a small gap 
will appear between the push rod 66 (FIG. 14) and the contact surface of 
bellcrank 60. The magnitude of this gap is dependent on the various error 
and/or wear (stack up) of all the components involved in the clamping 
system including the pallet feet 40. 
Several features of this clamping technique are to be noted. The clamping 
force applied to the clamp member 116 by the lever 100 through shoe 114 is 
applied on the same axis A.sub.4 as the clamp force applied by the clamp 
member 116 to the pallet shoe 40; i.e., these two forces act on coincident 
axes. The clamp member 116 will deflect slightly, but since it is mounted 
in the housing 54 through an elastomeric bushing, these deflections impose 
no significant loads on the housing 54. The only significant reactive 
loads on the housing 54 due to the clamping forces are a compressive load 
equal to the clamp force which exists between the locator pad 120 and the 
reaction pad 110 and a moment equal to the clamp force times the distance 
between axis A.sub.3 and axis A.sub.4 ; other much smaller forces are 
created by the reaction loads on shafts 64 and 88 and the spring cartridge 
support 74. These forces are considerably smaller because of the high 
mechanical advantage of clamp levers 100 and 102. 
The unclamp sequence is caused by the upward movement of push rod 66, FIG. 
14, which rotates bellcrank 60 and torque tube 62 counterclockwise and 
compresses spring 80. Arm 82 is rotated counterclockwise lifting links 92 
and 96 upward; this rotates clamp lever 100 counterclockwise and clamp 
lever 102 clockwise. The resilient pads 124 expand upward forcing the 
clamp members 116 to move up as permitted by the shoes 114. The clamp 
members 116 relieve their clamp force on the pallet shoes and continue 
upward to create a clearance between the upper faces of the pallet feet 40 
and the clamp forces 118 of the clamp members 116. 
Since the slide rails on which the pallet moves are subject to wear, it is 
desirable that they be eliminated from the accurate location functions 
which are the object of the present invention. This is accomplished in the 
following manner. 
The rotation of the torque tube 62, in addition to operating the clamp 
system just described, also slightly lifts and lowers the slide rails 130 
(FIGS. 12 and 13) on which the pallet base 42 is supported through pallet 
feet 40 as it is moved by the transfer bar 48. Referring to FIGS. 12 and 
13, the slide rails 130 are shown in their down position when the pallet 
feet 40 are resting on locator pads 120 and clamped by clamp members 116. 
A slight clearance will be noted between the upper surface of the slide 
rails 130 and the mating surface of the pallet feet 40; when clamped, the 
pallet is, therefore, supported only by the locator pads 120. When the 
pallet 42 is fully unclamped, the slide rails 130 move upward slightly to 
contact and lift the pallet feet 40 upward and a slight clearance develops 
between the upper surface of the locator pads 120 and the corresponding 
contact surfaces of the pallet feet 40. The surfaces on the pallet feet 40 
which contact the locator pads 120 never contact the slide rails 130 and 
the surfaces on the pallet feet 40 which contact the slide rails 130 never 
contact the locator pads 120. This is very important since wear on the 
pallet feet 40 and/or slide rails 130, due to pallets sliding on slide 
rails 130 during transfer, does not influence final pallet location in the 
vertical plane. The only sliding which takes place on the locator pads 120 
is the small movement which takes place in the locating process which only 
corrects pallet location errors due to slight transfer inaccuracies. 
Referring to FIGS. 13 and 16, each slide rail 130 is supported by two rods 
132 which can slide vertically in the housing 54. The lower ends of the 
rods 132 ride on cams 134 mounted on an auxiliary shaft 136. An actuator 
arm 138 is also mounted to shaft 136; the outboard end of this arm 138 is 
connected to and driven by a link 140 connected to a cam arm 142 (FIG. 16) 
mounted on the torque tube 62. Since the shaft 136 and torque tube 62 
rotate on axes which lie at right angles to each other, the arm 138 and 
the arm 142 rotate in planes which are at right angles. Accordingly, the 
link 140 is connected at one end to the arm 138 through a spherical 
bearing 144; at its other end, the link 140 is connected to the cam arm 
142 through a spherical bearing 146. Since the rotation of both the torque 
tube 62 and the shaft 136 is through relatively small angles, this 
spherical bearing and link connection is satisfactory. 
It can be seen that when the torque tube 62 rotates in the counterclockwise 
direction (as in unclamping) the cam arm 142 moves the link 140 upward. 
This causes the shaft 136 to rotate clockwise, as viewed in FIG. 13; and 
this causes the cams 134 to lift the rods 132 which support a slide rail 
130. The slide rails 130 contact the pallet feet 40 to lift them slightly 
from contact with locator pads 120. The pallet 42 is slid out of the 
registry in this configuration and the next pallet enters. 
Similarly, it can be seen that during the clamping sequence, the slide 
rails 130 are lowered and the pallet feet 40 are supported by the locator 
pads for clamping. As the torque tube 62 rotates clockwise, for clamping, 
the link 140 moves downward causing the shaft 136 to rotate 
counterclockwise; the cams 134 mounted thereon permit the rods 132 to move 
downward with the slide rail 130 as driven by the weight of the pallet 42. 
In actual operation, no clearance may develop between the upper surface of 
slide rail 130 and pallet feet 40 but this is of no consequence as long as 
the pallet feet 40 are located by locator pads 120. Indeed, it is 
desirable that clearance does not develop since then foreign material such 
as chips cannot enter. A positive method to prevent clearance from 
developing will subsequently be disclosed. 
In addition to the clamping and slide rail vertical movement generated by 
the rotation of the torque tube 62, the locating sequence is also operated 
thereby. As a pallet 42 is moved into a given registry by movement of the 
transfer bar 48, the inner vertical faces 150 of two pallet feet 40 either 
clear or lightly contact two Y axis locators 152 mounted on upward 
extending protrusions 154 on the housing 54; this is also shown in the 
partial vertical section (FIG. 17). These locators 152 are the functional 
equivalent of the locators 4 in FIG. 1-6. 
A fixed locator 156 is mounted to the housing 54 and is the functional 
equivalent of the fixed locator 12 in FIGS. 7-11. This locator 156 has two 
accurately positioned faces 158 which are inclined to a line perpendicular 
to the plane of locators 152, in any horizontal plane, and which are also 
inclined with respect to the vertical Z axis. A corresponding locator 50, 
previously noted, is mounted on the underside of the pallet base 42. This 
locator has four sides which are symmetrically disposed about the central 
vertical axis of the pallet. Only one of these sides is relevant to the 
location of a pallet in any one given attitude, that side which is 
parallel to and adjacent to the locator 156 on the housing 54. Considering 
this one side only, it has two accurately positioned faces 160 which are 
inclined to a line perpendicular to the plane of the locating surfaces 150 
on feet 40, in any horizontal plane, and which are also inclined with 
respect to a vertical axis. The vertical inclination of the faces 160 on 
locator 50 and faces 158 on locator 156 are such that they can be mutually 
tangent to a cone having a vertical axis, if the locator 50 is properly 
aligned with the locator 156 in the X plane. In effect, the locator 50 is 
analogous to locator 16 in FIGS. 7-11. 
A conical locator 162 in the form of a frustcrum of a cone is moved 
vertically into and out of the four-sided pyramidal interspace created by 
faces 158 on locator 156 and faces 160 on locator 50 by a mechanism 
actuated by the rotation of the torque tube 62. Referring to FIG. 16, the 
cam arm 142 mounted on torque tube 62 has cut into it a contoured cam 
groove 170 in which is guided a cam follower roller 172. This roller 172 
is mounted on a bellcrank 174 which is mounted on a shaft 176 journalled 
in the housing 54. A link 178 operating in a substantially vertical plane 
is connected at its upper end to the bellcrank 174 through a spherical 
bearing 180. Referring also to FIG. 13, the lower end of link 178 is 
connected through a spherical bearing 182 to a sliding driver sleeve 184. 
This sliding driver sleeve 184 is mounted in a long bushing 186 in which 
the sleeve 184 can slide vertically. It will be noted that the spherical 
bearing 182 is connected to the sleeve 184 through a boss 188 on the 
sleeve 184 which extends through a slot 190 in the bushing 186. 
A secondary sliding member 192 is also slidably mounted in the bushing 186; 
it is connected to the sleeve 184 through a compression spring 194 and a 
preload rod 196. The preload rod 196 is concentrically mounted in the 
sliding member 192 and passes through a loose fitting hole in the sleeve 
184, below which a head 198 is formed on the rod 196. This rod 196 is used 
to create a predetermined preload on the spring 194. 
The conical locator 162 is mounted to the top of the sliding member 192 in 
a manner that permits it to float thereon. Referring to the partial 
sectional drawing FIG. 18, the conical locator 162 is fastened to the top 
of the sliding member 192 with a single concentric screw 200. An 
elastomeric washer 202 is positioned between the bottom face of the 
conical locator 162 and the upper face of the sliding member 192. A 
relatively large clearance is provided between the inside diameter of the 
conical locator 162 and the outside diameter of the screw 200. The conical 
locator 162 is held concentric with the screw, under no load conditions, 
through two elastomeric "O" rings 204, made of neoprene or comparable 
material. This type of mounting permits the float required of the conical 
locator 162, and also permits it to rotate for uniform wear distribution. 
The mechanism position shown in FIGS. 13 and 16 shows the torque tube 62 
rotated as far clockwise as permitted by the clamp member 116 equilibrium 
and the conical locator 162 is held upward into the interspace between 
locators 50 and 156 with a force determined by the preload on spring 194. 
During the unclamp cycle, the torque tube 62 rotates counterclockwise 
carrying the cam arm 142 with it. It can be seen that after approximately 
midstroke, the cam roller 172 is moved to the left by cam groove 170 as 
viewed in FIG. 16; this causes a clockwise rotation of the bellcrank 174 
about the axis of shaft 176. The link 178 moves downward driving the 
sleeve 184 downward also. After a very short downward movement of the 
sleeve 184, during which interval the spring 194 expands, the sleeve 184 
contacts the head 198 of the rod 196. From this point onward, the sleeve 
184, sliding member 192, and conical locator 162 move downward together, 
until the conical locator 162 is completely clear of the locators 50 and 
156; this corresponds to the full counterclockwise position of the torque 
tube 62. 
The locating sequence is the exact converse. This occurs during the 
clockwise rotation of the torque tube 62. During approximately the first 
half of this rotation, the cam roller 172 is driven to the right as viewed 
in FIG. 16; this causes the bellcrank 174 to rotate counterclockwise about 
the axis of shaft 176 raising the link 178. The sleeve 184, spring 194, 
sliding member 192, and conical locator 162 move upward together as driven 
by link 178. The conical locator 162 forces the pallet 42 into its final 
located position, at which time it is simultaneously tangent to all four 
faces 158 and 160 and its further upward movement is prevented. The 
preloaded spring 194 is then compressed slightly as the sleeve 184 is 
driven to the top of its stroke by the link 178, bellcrank 174, cam 
follower 172, and cam groove 170. This compression of spring 194 serves 
two useful purposes; it limits the upward force exerted by the conical 
locator on the locators 50 and 156, and it automatically compensates for 
the wear on all three locators 50, 162, and 156. 
As noted in connection with the locating process described for FIGS. 7 to 
11, the conical locator 162, in being permitted to float with respect to 
sliding member 192, establishes a position for the pallet locator 50 
relative to the locator 156 on the registry such that the conical locator 
162 is simultaneously tangent to the two faces 160 and the two faces 158. 
The pallet location is determined solely from the locator 156 and slight 
errors or wear in the lift and guidance mechanism for the conical locator 
162 is of no consequence. 
It can be seen from the shape of the cam groove 170 that the raising of the 
conical locator 162 and its associated mechanism is generated during 
approximately the first half of the clockwise rotation of the torque tube 
62 and cam arm 142. During the remaining approximate half of the clockwise 
rotation of the torque tube 62 and cam arm 142, the cam roller 172 is in 
dwell and no further motion of the bellcrank conical locator 162 and 
intermediate details takes place. During this interval of the cam arm 142 
rotation, the cam roller 172 engages a portion of the cam groove which is 
a true radius about the centerline of shaft 64. This is desirable since it 
insures that the conical locator 162 has fully located the pellet before 
the clamp members 116 clamp the pallet feet 40, and that no motion of the 
locating system occurs during the clamping process. 
It can be seen from a study of the locating system shown in plan view in 
FIG. 12 that the Locating Ratio, as previously defined, is very large, 
i.e., the ratio of the distance between the fixed locators 152 to the 
distance between the line connecting the fixed locators 152 to the 
locating force application point, faces 160, is very large. It can further 
be seen that since the faces 160 on the locator 50 are on the opposite 
side of fixed locators 152, the pallet base 42 is pulled into location 
rather than being pushed into location, which is a more desirable 
condition. The pallet base 42 is located solely from the locating 
mechanism which is housed in or mounted on the housing 54. 
As described above, this housing 54 also contains mechanisms which clamp 
the pallet and raise the one transfer rail slightly during pallet 
transfer. The mechanism housed within the secondary housing 56 is 
substantially identical with the mechanism housed within the primary 
housing 54, except that the entire operating mechanism associated with the 
conical locator 162 does no exist within the secondary housing 56. The 
secondary housing 56, as shown in FIG. 16, contains the spring cartridge 
and clamp mechanism shown in FIGS. 14 and 15 and it also includes the 
shaft 136, cams 134, rods 132, and vertically moving slide rail 130. The 
torque tube 62 is shortened and the cam 174 does not exist. The link 140 
is now connected to the arm 82 mounted on the torque tube 62 rather than 
the non-existent cam arm 142. The mechanism for clamping and raising and 
lowering of the slide rail 130 in the secondary housing 56 is actuated by 
a duplicate push rod 66 actuated by the same external drive system which 
actuates the push rod 66 associated with the primary housing 54. 
It can be seen from the plan view, FIG. 12, that the pellet base 42 has 
four way symmetry, the pallet could be rotated 90.degree. and appear 
exactly as it does before rotation. This condition is created by having 
four symmetrically disposed pallet feet 40 mounted equidistant from the 
pallet 42 centerline, and by designing the pallet locator 50 such that it 
has four identical sides, each with the inclined angled locator faces. 
Therefore through the use of suitable rotate-stations positioned as 
required along the line of travel of the pallets as they move through a 
multiple station transfer machine, the pallets may be rotated in 
90.degree. intervals and still be located and clamped by the aforesaid 
registry mechanism. This technique is very useful in that it makes 
workpiece faces accessible for operations that would otherwise required 
refixturing. 
As described above, the total registry mechanism lowers the pallet 42 
slightly on the slide rails 130, locates it with an upward moving floating 
conical locator 162, and clamps it with four clamp members 116. This must 
be accomplished in exactly the correct sequence, as is very easily 
accomplished with the fully mechanically interrelated motions. An 
illustrative timing chart is shown in FIG. 19, which shows the movement 
generated by the torque tube 62 in the conical locator 162, pallet (slide) 
rails 130 and clamps 116, to accomplish the required interrelationships. 
The conical locator 162 has been shown and described as a cone which causes 
the pallet to be located by forcing itself to become mutually tangent to 
four locator surfaces 160 and 158, two on the pallet locator 50 and two on 
the registry locator 156. In such a position, the conical locator 162 is 
in line contact with these four faces. An alternate design for the conical 
locator is shown in plan view in FIG. 20 and in side view in FIG. 21. This 
alternate pyramidal tapered locator 206, is provided with four locator 
faces 208, essentially a frustrum of a pyramid, which, when final pallet 
location is achieved, are simultaneously in contact with the faces 158 and 
160 on the registry locator 156 and pallet locator 50. Location is 
therefore achieved through area contact, rather than line contact as with 
the conical locator 162. This area contact is advantageous, since it is 
less susceptible to wear; on the other hand, it has a greater 
susceptibility to trapping of dirt, chips or other contaminants between 
the locating surfaces. In any case, the tapered locator can be conical in 
form as shown by the locator 162 or pyramidal in form as shown by the 
locator 208, each with its particular advantages. 
It will be recalled that the slide rails 130 are moved up and down slightly 
as supported by the rods 132, which are driven by cam 134. In some 
installations, when the slide rails are in their lowermost position, it 
may be desirable that the slide rails 130 remain in contact with the 
underside of the pallet feet 40 to prevent the entry of chips or other 
contaminants. Since this is an indeterminate condition, depending on the 
degree of wear on the top of the rails 130 and the associated areas of the 
pallet feet 40, as well as the slight dimensional manufacturing errors of 
the rods 132 and cams 134, other means are required. 
Two techniques for maintaining the slide rails 130 in contact with the 
pallet feet 40, even when the cams 134 are in their full down position, 
are shown in FIGS. 22 and 23. In FIG. 22, a rail support rod 210 
(replacing rod 132) supports the slide rail 130 as before, and its lower 
end is actuated by a cam 134 like that shown in FIG. 13. The rod 210 is 
slidably mounted in the frame 54, and is additionally mounted in a 
commercially standard rubber bushing 212, comprised of an outer flanged 
metal shell 214, an inner metal sleeve 216, and a rubber, or other 
elastomer, bushing 218 bonded to each. The shell 214 is press fitted into 
the frame 54, and the rod 210 is axially supported by the the sleeve 216 
through a shoulder 220 on the rod 210. The bushing 212 deflects in shear 
during the vertical movement of the rod 210, and it is biased so as to 
exert an upward force on the rod 210 which is less than the weight of the 
pallet 42 but more than the weight of the rail 130 and rod 210. Therefore, 
as the cam 134 lowers the rod 210, rail 130, and pallet 42, they move 
downward against the bias of the rubber bushing 212, until the pallet feet 
40 contact the locators 120, establishing the vertical position of the 
pallet 42. Since the pallet 42 is now so supported, it no longer exerts a 
downward force on the rails 130, which then no longer move further 
downward against the upward bias of the rubber bushing 212, even though 
the cam 134 permits a slight further downward movement. In essence, the 
upward bias of the bushings 212 prevents a gap from opening between the 
rails 130 and the pallet feet 40, yet permits the pallet 42 to move up and 
down slightly as previously described. 
Another way of accomplishing this same upward bias on the rails 130 is 
shown in FIG. 23. In this case, the rail 130 is supported by a rod 222, 
replacing rod 132; the rod 222 is again slidably supported in the housing 
54. A shoulder 224 on an enlarged section of the rod 222 is supported by a 
compression spring 226 which in turn is supported by a shoulder 228 formed 
in the housing 54. This compression spring 226 is preloaded and exerts an 
upward force on the rod 222 which is less than the weight of the pallet 
42, but greater than the weight of the rail 130 and rod 222. Accordingly, 
the spring 226 prevents the rails 130 from moving downward from the pallet 
feet 40 when they are supported by the locators 120, as has been described 
in connection with the rubber bushing 212 in FIG. 22. 
Reverting to FIG. 14, the spring cartridge 72 shown there utilizes a coiled 
wire spring operating in compression. Another type of spring cartridge is 
shown in FIG. 24; in this design, the elastic element is comprised of a 
stack of disc springs, also referred to as Belleville washers. Referring 
to FIG. 24, a pull rod 230 is connected to the nosepiece 70 (as in FIG. 
14); the other end of the pull rod 230 is formed into a head 232. A stack 
of disc springs 234 are concentrically positioned and preloaded on the 
pull rod 230 between the head 232 and an internal flange 236 on a sleeve 
238; this sleeve 238 is also provided with a mounting lug 240 through 
which it is attached to the housing 54. Each disc spring 234 is a conical 
shaped washer, which in compression becomes more nearly planar. A stack of 
disc springs 234, as in FIG. 24, is generally to be preferred over a more 
conventional wire coil spring because a larger amount of work or energy 
can be stored in a given volume. 
An alternate design for the spring cartridge, while still using disc 
springs, is shown in FIG. 25. Here a stationary sleeve 242 is mounted to 
the housing 54 through a mounting lug 244 which is also formed into a 
shoulder or external flange 246. A series of disc springs 250 is stacked 
on the outside of the sleeve 252 and bear againt the flange 246. 
At the other end of sleeve 242, ths stack of disc springs 250 is preloaded 
against a shouldered washer 252, which is held in place by a thin flat 
keeper 254 extending across a diameter of the washer 252 passing through 
two longitudinal slots 256 in the sleeve 242 and also passing through a 
slot 258 in a pull rod 260. At its other end, the pull rod 260 mounts the 
nosepiece 70. It can be seen that the tensile load in pull rod 260 is 
transmitted by the keeper 254, acting as a beam, into a compressive load 
on the stack of disc springs 250. As the pull rod 260 moves through its 
stroke, as determined by the mechanism, the keeper 254 remains loaded 
against the right side of slot 258 in pull rod 260, but the keeper 254 
moves freely through the clearance slots 256 in sleeve 242. 
Referring to FIGS. 13, 14 and 15, it will be recalled that the resilient 
pad 122 is utilized to return the clamping member 116 to its unclamped and 
clearance position upon release of the clamp force generated by clamp 
lever 100. It will be understood that alternate elastic return systems can 
be used to create this same return force, among which, by way of 
illustration, are, a conventional wire coil spring acting in compression, 
or a short stack of disc springs comparable to those shown in FIGS. 24 and 
25. 
In the previous descriptions of the locating system, the axis of the moving 
tapered locator was shown as being substantially parallel to the Z axis. 
This need not be the case; there are some advantages to slightly inclining 
the axis of the tapered locator and the axis on which it moves into the 
interspace between the locator on the pallet and the corresponding fixed 
locator on the registry. Such a system is shown in FIGS. 26 and 27. 
Referring to these figures, a locator 232 is mounted to the underside of 
the pallet 42 and is analogous to the locator 50 previously described. It 
incorporates two faces 234 and 236 which are oppositely inclined to the Y 
axis and which are parallel to the Z axis; i.e., they are perpendicular to 
the X-Y plane. It will be understood that the locator 232 may also have 
four sided symmetry and that each side incorporates faces corresponding to 
faces 234 and 236. 
A fixed reference locator 238 is mounted to the registry frame 54 and is 
analogous to the fixed reference locator 156 previously described; it 
incorporates two faces 240 and 242 which are also oppositely inclined to 
the Y axis, and additionally inclined to the Z axis. 
A conical locator 244, analogous to the previously described conical 
locator 162, is configured to be simultaneously tangent to faces 234, 236, 
240 and 242 when the pallet locator 232 is properly located with respect 
to the registry mounted fixed reference locator 238. The conical locator 
244 is resiliently mounted on an actuating member 246, analogous to member 
192 previously described. Both the axis of the conical locator 244 and the 
path of the actuating member are along an inclined axis A.sub.5. The 
operation of this system of location is substantially the same as 
previously described, in that the conical locator 244 is forced upward 
until simultaneous tangency with the four faces 234, 236, 240 and 242 is 
achieved. This system differs from that previously described only by being 
rotated in space through a small angle such that faces 234 and 236 become 
perpendicular to the X-Y plane. It can be seen that the relatively small 
inclination of the axis A.sub.5 causes only small changes in the forces 
which bring the locator 232 and the pallet, on which it is mounted, to its 
final located position. The practical advantage of this inclination of 
axis A.sub.5 are twofold: first, the lifting forces on the locator 232 and 
therefore on the pallet, are significantly reduced; and, secondly, the 
manufacturing costs on the locator 232, which has four identical pairs of 
locating faces, are reduced, since these locating faces are now on simple 
rather than compound angles or inclinations. 
This system, using an inclined axis A.sub.5, can also be used with a 
pyramidal tapered locator as previously described. For manufacturing 
convenience, the faces 234, 236, 240 and 242 as well as the previously 
described faces 160 and 158 have been shown as planes. This need not be. 
It is sufficient that these faces be reproducible surfaces, generally 
converging to a common apex and capable of having four lines or areas of 
tangency with a tapered locator. 
The tapered locators 244 or 162 or 206 have been shown as being mounted on 
a member which moves in a straight line to carry the tapered locator into 
the interspace between the pellet locator and registry locator until four 
line tangency is reached. It can be seen that a pivoted or parallelogram 
type motion for moving the tapered locator to its final locating position 
is also suitable if the arcuate path so generated is sufficiently close to 
a straight line to be compensated for by the aforementioned float made 
possible by the resilient mounting of the tapered locator on its 
supporting member. 
Referring again to FIG. 14, it will be recalled that the entire registry 
mechanism is actuated by an externally driven push rod 66, which, in 
driving the torque 62 counterclockwise, releases the clamp, withdraws the 
tapered locator, and lifts the pallet slightly upward off the vertical 
locators. Any one of a wide variety of mechanisms is suitable to 
accomplish this. If the multiple registries of a multiple station machine 
are to be independently actuated, a simple air or hydraulic cylinder can 
be used in place of the push rod 66. 
In another arrangement, FIG. 28, all the push rods 66 associated with the 
multiple registries of a multiple station machine are operated from a 
single source. Two machine beds 250 are shown for illustrative purposes; 
it will be understood that there may be multiple additional machine beds 
250 with their associated mechanisms. A registry frame 54 is mounted on 
each machine bed 250, and the slide rails 130 span the registries 54. The 
machine beds are interconnected by spacers 252. A bellcrank 254 is pivoted 
in each machine bed 250 through a shaft 256; each bellcrank consists of a 
short horizontal arm 258 and a long vertical arm 258. The outboard end of 
each arm 258 is pivotally connected to a push rod 66. The outboard lower 
ends of the arms 258 are pivotally interconnected by links 260 which lie 
in substantially horizontal planes. One of the arms 258 is driven by an 
air or hydraulic cylinder 262. It can be seen that as the cylinder 262 
retracts, all the bellcranks 254 rotate clockwise in unison causing the 
push rods 66 to move upward in unison; this unclamps all registries, 
retracts the tapered locators, and lifts the pallets slightly upward on 
the rails 130. When the cylinder 262 extends, all bellcranks 258 rotate 
counterclockwise, lowering the push rods 66 and permitting the internal 
spring cartridges to lower, locate and clamp the pallets. 
The use of a cylinder with this linkage is illustrative only; it will be 
understood that the horizontal movement of the links 260 can be generated 
by a gear reducer, driven by an electric motor, and having a crank on its 
output shaft connected to one of the arms 258 by a suitable connecting 
rod. The multiple bellcrank linkage can also be advantageously driven by 
one of the mechanisms described in my U.S. Pat. Nos. 3,789,676, 3,857,292 
and 4,075,911. 
Another means for actuating all the push rods in unison is to mount a long 
torque tube horizontally through the machine beds, suitably journalled 
therein, which is oscillated through a small angle about its horizontal 
axis. At each station, an arm is fastened to the torque tube and the 
outboard end of each arm drives the vertically moving push rod 66 through 
a pivot connection. The torque tube in turn is driven by a suitable arm, 
fastened thereon, which in turn may be driven by a cylinder, connecting 
rod, crank, gear reducer and motor, or the like. It can be seen that two 
torque tube assemblies are required, one to operate the push rods on one 
side of the registry line, and a second to drive the push rods on the 
other side of the registry line. 
The above-described mechanisms are all addressed to actuating the 
registries through the push rods 66. The registries can be altered to make 
them operable by other means. One such alteration is shown in FIG. 29; the 
bellcrank 60 (FIG. 14) is replaced by a master lever 270 attached to the 
torque tube 62. The upper end of the lever 270 is still operated by the 
spring cartridge 72 through a tension rod 76 and nosepiece 70 and wear rod 
68; but whereas the bellcrank 60 had been operated by a vertically moving 
push rod 66, in the alternate arrangement (FIG. 29) the torque tube 62 is 
driven by the downwardly extending portion of the master lever 270 from a 
suitable horizontal actuating system. It can be seen that a horizontal 
movement to the right imparted to the lower end of master lever 270 causes 
the torque tube 62 to rotate counterclockwise thereby releasing the 
clamps, withdrawing the tapered locator, and slightly lifting the slide 
rails; a release of the force causing this movement to the right of the 
lower end of master lever 270 permits the spring cartridge to rotate the 
torque tube 62 clockwise, lowering the rails, extending the tapered 
locator, and clamping the pallet. 
An illustrative system for actuating the master levers 270 is shown in FIG. 
30. A pallet registry 54 is mounted on each machine bed 250. Two stations 
are shown; it will be understood that the actuating system extends through 
as many stations as exist for the overall transfer machine. An actuator 
bar 272 extends through the machine beds 250; it is intermittently 
supported by rollers 274 mounted on the machine spacers 276. At its one 
end the actuator bar 272 is driven by an air or hydraulic cylinder 278 
mounted on the machine bed 250. A series of actuating pins 280 are 
fastened to the bar 272. These extend transversely to one side of the bar 
272 to operate in the plane of the master levers 270, which are disposed 
to one side or the other of the plane of the bar 272. When the cylinder 
278 retracts, the actuator bar 272 moves to the right, and the pins 280 
contact the master levers 270, driving them counterclockwise and 
unclamping the registries. When the cylinder 278 extends, the bar 272 
moves to the left and the resulting motion of the pins 280 permits the 
spring cartridges in the registries to move the levers 270 with them; as 
each registry reaches its equilibrium clamped position, its lever 270 
stops moving, and a small gap develops between each lever 270 and its 
corresponding actuating pin 280. 
In the preceding descriptions, it was assumed that the pallet feet 40 and 
the rails 130 operated in a substantially horizontal plane, as represents 
the very great majority of applications. It was within this context that 
the term "vertical" applied, especially as related to the movement of the 
tapered locator. It will be understood that the registries can also be 
operated with the rails and pallet feet operating in non-horizontal 
planes, in which case the term "vertical" will be understood as being 
substantially perpendicular to the plane of operation.