Full access pallet shuttle guarding

A machine tool has a pallet transfer system comprising a rotary deck having a pair of pallets oppositely disposed about a vertical rotary transfer axis, wherein at the transfer position, the pallets are further movable along a horizontal linear transfer axis toward and away from the pallet transfer system. A vertical guard plate is affixed to the rotatable section or deck of the transfer system, and the plane of the guard plate passes through the rotary transfer axis at an oblique angle to the linear transfer axis. The rotatable guard plate interacts with an elastomeric seal at the interface of a guard opening in a stationary guard assembly on a machine tool to substantially confine coolant overspray and the like within the machine guard enclosure. By passing obliquely across the linear transfer axes of the pair of parallel pallets, substantially full access of a stationary pallet lying outside the machine guard enclosure may be had.

BACKGROUND OF THE INVENTION 
This invention generally relates to automatic machine tools such as milling 
machines, machining centers and the like which employ a plurality of 
pallets capable of being automatically interchanged between a service 
station and a machining station. At a machining station, a pallet within a 
machine guard enclosure is positioned so that its respective workpiece is 
capable of being operated upon the machine, while a pallet lying at the 
service position, outside the machine guard enclosure, may be serviced for 
removing a finished workpiece and placing a rough workpiece on the pallet 
for a subsequent machining operation. 
It therefore becomes an important task for the designer to configure 
special guarding to complement a pair of pallets which may be carried on a 
rotary deck at a machine tool, with the following parameters in mind: (1) 
the guard should be of relatively simple design; (2) the guard should 
permit relatively full access to at least four sides of a pallet and 
workpiece; and (3) the guard should be operable to substantially fully 
enclose the machine guard system to prevent overspray of coolant and fly 
out of chips resulting from the machining operation. 
It is therefore an object of the present invention, to accomplish a 
substantially full access guarding system for servicing the pallets in a 
pallet shuttle system. 
Another object of the present invention, is to provide a simplified guard 
system for rotary pallet shuttle system capable of substantially enclosing 
a machining zone. 
SUMMARY OF THE INVENTION 
The invention is shown embodied in a machine tool having a machine tool 
pallet transfer system wherein a pair of similar pallets are oppositely 
disposed about a generally vertical rotary transfer axis wherein a deck 
carries the pair of pallets and the deck is rotatable about the vertical 
transfer axis to alternate the pallets between an exterior service, 
station and an interior machine interchange station. The machine tool has 
a machine guard assembly substantially enclosing the machining zone, and 
an opening is provided in the machine guard assembly in which is 
positioned the rotary deck of the transfer system. The transfer system is 
arranged so that the pallets are further movable along generally 
horizontal transfer axes toward and away from the pallet transfer system, 
wherein the transfer axes are oppositely disposed about the vertical 
transfer axis, parallel to one another. A pallet guard base is affixed to 
the rotatable deck and a generally planar guard body is affixed to and 
extends from the guard base, wherein the guard body passes through the 
vertical transfer axis along a line oblique to the linear transfer axes. 
The planar guard body is rimmed with an elastomeric sealing element which 
coacts with the opening in the machine guard assembly to substantially 
seal the interior of the machine guard assembly. The oblique attitude of 
the planar guard body relative to the parallel linear transfer axes in 
effect passes the guard across a corner of a rectangular pallet which may 
be carried on the pallet transfer assembly thereby permitting 
substantially full access to at least four sides of a pallet and 
workpiece, without unduly complicating the pallet guard structure.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 of the drawings depicts a machine tool 10 having a machining zone 11 
wherein a machine cutter 12 may interact with a positively located pallet 
13 carried on a machine registering means, herein depicted as a slideway 
14. The machining zone 11 is substantially enclosed by a machine guard 
assembly 15. 
The machine tool 10 employs a rotary pallet shuttle assembly 16 for 
alternately transmitting a finished workpiece (not shown) out of the 
machining zone 11 and a rough workpiece into the machining zone 11. The 
pallet shuttle assembly 16 basically is comprised of a stationary base 17, 
having a vertical rotary transfer axis 18 upon which is carried a 
rotatable deck 19, herein depicted as a frame having a plurality slideways 
20 for linear movement of a pallet on the slideway 20. A plurality of 
pallets 13,21 are utilized, which are substantially identical to one 
another, upon which are located respective workpieces (not shown) and the 
pallets 13,21 are oppositely disposed about the vertical transfer axis 18 
and offset therefrom so as to be parallel to one another and linearly 
movable on the deck slideway 20 along respective linear transfer axes 
22,23 toward and away from the pallet shuttle assembly 16. A pair of 
cylinders 24 are affixed to the pallet transfer deck 19, and a piston rod 
25 extending from the cylinder 24 may be coupled through a suitable clamp 
26, to move the pallets 13,21 along the linear transfer axes 22,23 at a 
desired time. The pallet 21 lying outside the general machine guard 
assembly 15 is considered a service station, wherein an operator may 
interact with a workpiece on the pallet 21 for a variety of purposes, such 
as location and inspection. The pallet shuttle assembly 16 sets within an 
opening 27 in the machine guard assembly 15, and the opening 27 is 
subtended by a substantially planar pallet guard 28 which is affixed to 
the pallet deck 19, and rotatable about the vertical transfer axis 18. The 
pallet guard 28 lies at an oblique angle to the linear transfer axes 22,23 
of the pallet shuttle assembly 16, such that it passes across a corner 29 
of a respective rectangular pallet 21 thereby permitting substantially 
full access to at least four sides 21a,b,c,d of the pallet 21 and 
workpiece. The pallet guard 28 has a strip of elastomeric material 30 at 
each vertical end 28a,b which may coact with the machine guard opening 27 
to substantially enclose the machining zone 11 and prevent the overspray 
of coolant and fly-out of chips which may result from a machining 
operation. After a machining operation, the pallet 13 in the machining 
zone 11 is withdrawn by the piston rod 25 to the phantom position shown 
for a subsequent interchange of pallets. At such interchange time, the 
pallet deck 19 is rotated 180 degrees to bring the service position pallet 
21 into alignment with the machining zone 11 and the machining zone pallet 
13 to the service position. At such interchange time, the machine guard 
opening 27 is exposed, and after the interchange is completed, the pallet 
guard 28 closes off the opening 27 once again. 
Referring to FIG. 2, the pallet shuttle base 17 is shown as being a 
substantially vertical tube assembly 31 having a lowermost plate 32 which 
is provided with adjustable floor supports 33. The vertical tube assembly 
31 contains a bearing system 34 to journal the spindle 35 of the pallet 
transfer deck 19. The transfer deck 19 is provided with rotary drive gears 
36,37 and motor assembly 38 to accomplish the rotation and interchange of 
the pallets 13,21. The topmost surface 39 of the pallet deck 19 carries a 
plurality of deck slideways for slidably carrying the service station 
pallet 21 shown in solid and the machine zone pallet 13, shown in phantom. 
The substantially vertical planar pallet guard 28 has an angled top edge 
40 for stiffening purposes and a bottom edge 41 secured to the pallet deck 
surface 39 by screws 42 and the elastomeric sealing strip 30 is secured to 
the vertical ends 28a,b of the planar pallet guard 28 by screw fasteners 
43. The elastomeric sealing strip 30 is shown coacting with the opening 27 
in the machine guard assembly 15 to effectively seal the machining zone 
11. 
It is not intended that the invention be limited to the specific embodiment 
shown therein, but rather the invention extends to all such designs and 
modifications as come within the scope of the appended claims.