Article inverter

A method and apparatus for inverting planate articles, such as door and window assemblies, which are supported from below in the horizontal plane, such as at a workstation for carrying out fabrication procedures from above the article. The article is tilted to a near vertical position at a tilting station, moved horizontally away to provide clearance from the tilting station, rotated a half turn about its vertical axis, returned to the tilting station and tilted back to the horizontal attitude with the original underside now on top. A tilt table that rotates around a transverse axis intermediate its length supports the article at the horizontal and tilts it to the near vertical attitude. A carriage receives the tilted article from the tilt conveyer and supports it at the near vertical by a turntable on the carriage having supports that engages the leading end and back side of the article. The carriage is movable to and from a location a distance from the tilt table for rotating the turntable a half turn at that location. The carriage is returned to the tilt table location for transfer back to the tilt table for tilting back to the horizontal in the inverted mode.

BACKGROUND OF THE INVENTION 
This invention relates to equipment for inverting planate workpieces or 
other articles, particularly large flat workpieces, such as prefabricated 
door and window assemblies. This equipment is particularly useful for 
operations in which the planate workpiece is supported in the horizontal 
plane for carrying out assembly and other fabrication procedures. Access 
to the underside of the workpiece is necessary for various procedures and 
such access is quite difficult without inverting the workpiece so that the 
other side may be worked on from above. Heretofore, planate articles 
supported in a horizontal attitude have been inverted by rotation a full 
180 degrees about a horizontal axis. Typically, the workpiece is raised 
above its horizontal support in order to be "flipped" to the other side. 
However, inverting the article in this fashion requires a large amount of 
"head room" above the horizontal support, particularly for tall and/or 
wide planate articles. Typically, the article also must be supported 
against free fall during rotation and repositioning of it on the support 
to avoid damage. Such procedures usually require complex and bulky 
equipment. 
There is therefore a need for more efficient procedures and equipment for 
inverting planate articles. 
SUMMARY OF THE INVENTION 
This invention relates to a method and apparatus for inverting planate 
workpieces or other articles, particularly large flat workpieces, such as 
prefabricated door and window assemblies. This equipment and procedure is 
particularly useful for operations in which a planate workpiece is 
supported from below in a horizontal attitude for carrying out assembly 
and other fabrication procedures. 
In the method of this invention planate articles which are borne or carried 
in a horizontal attitude are inverted to reverse the planate sides so that 
the former underside is on top. In this method the planate articles are 
tilted, in the direction of a major axis thereof, downwardly at a leading 
end, from the horizontal to a near vertical attitude, rotated a half turn 
about the axis, and then tipped back to the horizontal position. 
As another feature of the method of this invention, the article is 
supported along its length from underneath in the horizontal position and 
then after tilting it is supported at the leading end in the near vertical 
attitude for rotation. After rotation 180 degrees the article is tilted 
back up to the horizontal to again be supported along its length from 
underneath. 
As yet another feature of the method, prior to tilting the article in its 
near vertical attitude, it is moved horizontally away from the location to 
which it was tilted in order to provide clearance for the article to be 
rotated. Following its rotation, the article is returned to that location 
fir tilting back to the horizontal. 
In the apparatus of this invention a tiltable support means, such as a tilt 
table, is advantageously employed for supporting the planate article from 
underneath in the horizontal attitude and for tilting it downwardly at a 
leading end, in the direction of a major axis of the article, to the near 
vertical attitude. Means are provided to hold the article from sliding off 
the leading end of the tiltable support means when the article is tilted 
to the near vertical, desirably an curb or stop projecting above the 
support means, such as a ledge at the leading end of a tilt table. Means, 
such as a carriage adapted to cradle the article at its leading end, are 
provided to receive the article from the tilt table, to support the 
article at its leading end and to carry the article, thus supported, to 
and from a location away from the tiltable support means. Means are 
further provided, such as a rotatable carrier on the carriage, to 
facilitate rotation of article about a vertical axis when at the remote 
location. 
A more specific feature relates to a particular means for transferring 
support of the leading end of the article, when at its near vertical 
attitude, between the tiltable support means and the means for receiving 
and carrying the article to and from a remote location. In this feature 
the tiltable support means is a tilt table having an end support at its 
leading end for supporting the leading end of the article. The means for 
receiving and supporting the article from the tilt table comprises a 
carriage having a seat for receiving and supporting the leading end of the 
article that is vertically aligned with the end support on the tilt table 
when the tilt table is at the near vertical attitude and the carriage is 
at a retracted position. Means are provided for positioning the tilt 
table, when at the near vertical attitude at a raised position and at a 
lowered position. At the raised position, the end support on the tilt 
table remains above the seat on the carriage. At the lowered position, the 
end support is below the end support on the carriage. Thus, when the tilt 
table carrying the article is moved to the lowered position, the seat 
engages the leading end of the article and support thereof is thereby 
transferred to the carriage. When the carriage is supporting the article 
at the retracted position and the tilt table is moved from the lowered 
position to the raised position the end support on the tilt table engages 
the leading end of the article to thereby transfer support of the article 
back to the tilt table. 
Another feature of the invention relates to a particularly advantageous 
means for moving a tilt table between a raised and a lowered position for 
effecting transfer of support between the tilt table and a carriage for 
receiving and supporting the article from the tilt table. For moving and 
supporting the tilt table between a horizontal and near vertical 
attitudes, the tilt table is provided with a pivot with an axis transverse 
to its longitudinal direction that is located a distance in the 
longitudinal direction from the leading end towards its trailing end 
thereof. The tilt table is rotatable about the pivot downwardly at the 
leading end from the horizontal to the near vertical attitude. Means are 
provided, such as a rocker, to support and move the pivot between a 
vertical location at which the tilt table is at the raised position, and a 
lower vertical location, at which the tilt table is at the lowered 
position. 
Yet another feature of the invention relates to a particularly advantageous 
means for receiving and supporting the article from the tilt table. In 
this feature the article is received and supported at a near vertical 
attitude in a cradle mounted on the carriage which comprises a seat for 
supporting the leading end of the article, stop means adjacent the seat in 
a direction to be forward of the front side of the article, such a curb or 
cleats, to restrain movement of the leading end of the article in the 
forward direction and a back support adjacent on the opposite side of the 
seat from the stop means and located a distance above the seat, to support 
the back side of the article. The article is received in the cradle at the 
near vertical with the back thereof leaning against the back support and 
the leading end sitting on the seat and restrained from forward movement 
by the stop means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The following description illustrates the manner in which the principles of 
the invention are applied but is not to be construed as limiting the scope 
of the invention. 
Article inverters of this invention are designed to invert, serially, one 
or more workpieces or other articles having sufficient planarity to be 
supported when resting on that side on a horizontal support, such as a 
conveyor surface. These may include articles having a pair of opposed 
generally planate sides that are relatively broad in relation to the 
thickness of the depth of the article and that are bounded by generally 
parallel top and bottom margins. The invention is particularly suitable 
for inverting large flat workpieces, such as prefabricated door and door 
jamb assemblies. This equipment is especially advantageous in operations 
in which the planate workpiece is supported in the horizontal plane for 
carrying out assembly and other fabrication procedures. Access to the 
underside of the workpiece is necessary for various procedures and such 
access is quite difficult without inverting the workpiece so that the 
other side may be worked on from above. 
The invention will be illustrated with apparatus for inverting 
prefabricated door and window assemblies. Door and window frames are 
pre-assembled and integrated units that may be inserted into a stud wall 
of a building under construction or renovation. These units are typically 
fabricated at elevated workstations on which they are supported in a 
horizontal plane for carrying out fabrication procedures from above at the 
upper side of the units. These workpieces are typically moved onto, off 
and between workstations by conveying apparatus that also maintains them 
in a generally horizontal attitude. The inverters of this invention may be 
employed before one of these stations for inverting the assembly so that 
the opposite side may be on at that station. However, inverters of this 
invention may be advantageously employed in a combined inverter and 
workstation function. That is, they may not only function as an inverter 
but as they support the workpiece in a horizontal raised position they may 
be employed as a workstation as well. 
For an introductory general description of the inverter and it's operation, 
FIGS. 1 and 2 of the drawings illustrate an inverter 1 which is composed 
of a stand 10 which serves to support tilt table 20, carriage 30 and the 
operators for these components, as will be described. Tilt table 20 is 
rotatable on stand 10 between a horizontal attitude as shown in FIG. 1 to 
a near vertical attitude as shown in FIG. 2. Carriage 30 is located at the 
base of stand 10 and is extendable laterally from stand 10 between a 
retracted position, as shown in FIG. 1, and an extended position, as shown 
in FIG. 2. Rotatable turntable 31 is mounted on carriage unit 30 for 
rotation about a vertical axis. 
FIG. 1 shows in phantom outline a typical unit under fabrication, door and 
window unit 2, the framing for which comprises a header 3, a footer 4 and 
inner jambs 5 and outer jambs 6. As shown, a door 7 is mounted between 
inner jambs 5 and windows 8 are mounted at either side, each between an 
inner jamb 5 and an outer jamb 6. The door and windows of unit 2 are 
applied at a previous workstation. Typically, at this stage trim pieces, 
such as beading, and/or aluminum or other cladding will be manually 
applied at both sides of unit 2. 
Door and window unit 2 is fed onto tilt table 20 by a conveying device (not 
shown) and moved therealong until the leading end 9 of the door unit 
(footer 4) abuts against support ledge 21 attached to the end of tilt 
table 20. In the inversion process, door unit 2 is brought to a nearly 
vertical orientation by rotation of tilt table 20 from the horizontal 
attitude as shown in FIG. 1 to a near vertical attitude as shown in FIG. 
2. Support ledge 21 engages leading end 9 of door unit 2 resting on tilt 
table 20 support unit 2 when the tilt table is rotated from the horizontal 
to the near vertical attitude of FIG. 2 to serve as a curb against 
movement of unit 2 off of tilt table 2. 
Carriage 30, when in the retracted position, is at a location to receive 
and support the door unit 2 when tilt table 20 is tilted to its near 
vertical attitude. At this attitude support of door unit 2 is transferred 
to turntable 31 of carriage 30, as will be described in more detail below. 
Carriage 30, now bearing door unit 2, is moved to the extended position as 
shown in FIG. 2. Turntable 31 is rotated a half turn, thereby to also 
rotate door unit 2 a half turn about its vertical axis. The extended 
position of carriage 30 is at a distance away from stand 10 sufficient to 
provide clearance therebetween for door unit 2 to be rotated about its 
vertical axis. Carriage 30 is then moved back to its retracted position 
and support of door unit 2 transferred back to tilt table 20. Carriage 30 
is again moved back to the extended position, to provide clearance, and 
tilt table 20 is then raised to the horizontal attitude and with it door 
unit 2, now in the inverted position. Further fabrication operations can 
then proceed on the upper side of door unit 2 while supported on inverter 
1 or after conveying the unit in the same horizontal attitude off of 
inverter 1 and to a separate workstation. 
To now describe inverter 1 in more detail, Stand 10 is comprised of four 
legs 11 secured together near their lower ends by struts 12 and by beams 
13 at their top ends. Beams 13 form a horizontal platform for receiving 
and supporting tilt table 20 in a horizontal attitude. A vertically 
adjustable prop 14 is located at each of the two corners adjacent trailing 
end 29 of tilt table 20. Props 14 may be used as further support for 
workpieces resting on tilt table 20 in a horizontal attitude, particularly 
when inverter 1 is also utilized as a workstation. 
Tilt table 20 comprises longitudinal frame members 22 bearing cross members 
23. Support ledge 21 is fixed to frame members 2 at the leading end 24 of 
tilt table 20. On either side of tilt table 20 is an outrigger 25, which 
is connected to longitudinal frame members 22 by struts 26. Outriggers 25 
provide lateral support for workpieces carried on tilt table 20 to prevent 
them form tipping over to either side, particularly when inverter 1 is 
employed as a workstation. Each outrigger 25 extends to an upright 27 at 
the end thereof at leading end 24. Uprights 27 on tilt table 20 assist 
support ledge 21 in supporting door unit 2 when it is rotated to the near 
vertical. 
Together, uprights 27 and ledge 21 act as a curb to prevent the article 
from sliding off the leading end of 24 of tilt table 20 when the tilt 
table tilts from the horizontal to a near vertical position. 
Cross members 23 are each provided at each end with a roller 28 having a 
rotational axis that parallels the axis of the cross member and is 
transverse to the longitudinal direction of tilt table 20. Rollers 28 
support and facilitate conveyance of workpieces onto and off of tilt table 
20 in the longitudinal direction thereof. 
Tilt table 20 tilts in the direction of its leading end 24. Thus, it is 
mounted for rotation between the horizontal and near vertical attitudes by 
means of a pair of bearings 40, one mounted on each of longitudinal frame 
members 22. Bearings 40 rotationally engage axle 41. Axle 41 is positioned 
a short distance beyond end 15 of stand 10 in the direction toward leading 
end 24 of tilt table 20. As best seen in FIG. 8, a piston 42 secured at 
one end by bracket 43 to a strut 12 of stand 10 and by bracket 44 at 
leading end 24 of tilt table 20. Actuation of piston 42 will cause tilt 
table 20 to rotate between the horizontal and near vertical attitudes. 
As best seen in FIG. 10, at its near vertical attitude tilt table 2 remains 
at a slight angle, tilted back from the vertical, so that door unit 2 
lying against it will also remain tilted back. This will maintain the 
center of gravity of door unit 2 behind its leading end 9 so that the unit 
will remain sitting on tilt table 20 without further propping. 
Axle 41 is also rotationally engaged by arms 45 of rocker 46, with one arm 
45 at the outer side of each bearing 40. Rocker 46 is rotationally mounted 
on stand 10 about two pivots 47 having the same axis, each pivot 
connecting one arm 45 with the respective beam 13 adjacent thereto. As 
illustrated in FIG. 10, rocker 4 is rotatable about the common axis of 
pivots 47 to raise and lower axle 41 between a raised position adjacent 
the top of stand 10 to a lowered position a distance therebelow. A piston 
48 is secured at one end to rocker bar 49 and at the other to bracket 50 
on a leg 11 of stand 10 to operate rocker 46 to raise and lower axle 41. 
As shown in FIG. 8, axle 41 is in the raised position when tilt table 20 
is in the horizontal attitude lying on stand 10. 
As seen in FIGS. 2. 5 and 8, bearings 40 are located a distance along tilt 
table 20 in the trailing direction from leading end 24. Thus when tilt 
table 20 is in the horizontal attitude lying on stand 10, leading end 24 
thereof extends a distance outwardly of end 15 of stand 10. As axle 41 is 
located adjacent the top of stand 10, leading end 24 will be lowered to a 
position close to the bottom of stand 10, as seen in FIG. 2 and 10, when 
tilt table 20 is rotated to the near vertical attitude. Also as shown in 
FIG. 10, when tilt table 20 has been rotated to the near vertical attitude 
rocker 43 may be pivoted to lower axle 41 to a lowered position. This will 
lower tilt table 20, and with it leading end 24, a further distance toward 
the bottom of stand 10 (as shown in phantom lines). 
Referring now to FIGS. 3, 4 and 8-13, carriage 30 comprises a tongue 32 
having a shank 33 and platform 34 for a rotatable carrier or turntable 31. 
Shank 33 is slidably mounted by tracks 35 on its underside on trackways 36 
carried by apron 37 for movement of platform 34 horizontally toward and 
away from stand 10 in a travel direction parallel to the longitudinal axis 
of tilt table 20. Apron 37 is fixed to the bottom of legs 11 at leading 
end 9 of stand 10 and it extends in the tongue 32 travel direction a 
distance both under stand 10 and outwardly beyond end 15 thereof to 
provide a bearing for shank 33. Shank 33 extends under stand 10 when 
tongue 32 is in a retracted position and is of sufficient length in the 
tongue travel direction to allow movement of platform 34 to an extended 
position a desired distance away from stand 20, as will be discussed. 
As best seen from FIGS. 4, 6 and 8-11, tongue 32 is moved between its 
retracted and extended positions by means of endless chain 51. Chain 51 
engages sprocket wheel 52 attached to a strut 12 of stand 10 and sprocket 
wheel 53 attached to apron 37 to provide a chain path in the travel 
direction of tongue 32. Chain 51 is attached at connector 39 to shank 33 
at its trailing end so that movement of chain 51 moves tongue 32 along its 
travel path. As seen in FIG. 8, axle 54 for sprocket wheel 52, which is 
mounted for rotation in bearings 55, also bears sprocket wheel 56 mounted 
on axle 53 above sprocket wheel 52. Chain 57 that engages sprocket wheel 
56 also engages sprocket wheel 58 and each end is connected to one of the 
two opposed piston rods 59 of two-way cylinder 60. Actuation of cylinder 
60 moves chain 57 to rotate axle 54 and thereby move chain 51. 
Referring particularly to FIGS. 7, 11 and 13, turntable 31 is mounted on 
platform 34 by axle 38 for rotation about a vertical axis. Turntable 31 
comprises plate 61 bearing axle 38 and support elements for cradling a 
planate workpiece at a near vertical attitude. Those elements include 
ridges 62, which function as a seat for supporting leading end 9 of door 
unit 2 and props 63 that project upwardly from plate 61 at the back side 
of ridges 62 to support the back side of door unit 2 that leans at a 
slight angle against props 63. A cleat 64 is positioned at the forward 
side of each ridge 62 to abut the forward edge of leading end 9 of door 
unit 2 as a curb or stop means to prevent the leading end from sliding 
forward on plate 61 and causing door unit 2 to upset. 
With tongue 32 in the retracted position and tilt table 20 is in the near 
vertical attitude, turntable 31 is in position to receive door unit 2 from 
tilt table 20. Props 63 are each on the outside of cross members 23 and 
inside of outriggers 25 on their respective sides and are in line with the 
top of tilt table 20. In this position ridges 62 on plate 61 lie 
side-by-side with support ledges 21 and to the outside thereof on their 
respective sides. As seen in phantom lines in FIG. 12. when axle 41 is in 
the raised position, support ledge 21 is a short distance above ridges 62 
and uprights 27 on outriggers 25. As seen in phantom lines in FIG. 13, 
when rocker 46 is actuated to move axle 41 to its lowered position, 
support ledge 21 moves to a position below the tops of ridges 62, thereby 
transferring the support of leading end 9 of door unit 2 from support 
ledge 21 to ridges 62. 
Reviewing the operation of inverter 1. Door unit 2 is first moved into 
place on tilt table 20 in the horizontal attitude as previously described. 
At this point axle 41 is in the raised position and tongue 32 is in the 
retracted position. Piston 42 is then actuated to move tilt table 20 to 
the near vertical attitude with door unit lying against it and with 
leading end 9 supported by ledge 21. Piston 48 is then actuated to operate 
rocker 46 to lower support ledge 21, transferring support of leading end 9 
of door unit 2 to ridges 62. Cylinder 60 is then actuated to move tongue 
32 from the retracted position to the extended position. As turntable 31 
moves forward with tongue 32, props 63 engage the back of door unit 2, 
serving as a back rest to support it at the near vertical position on 
turntable 31 in cooperation with ledges 21 and cleats 64. 
The operator then manually pivots turntable 31 a half turn to reverse the 
side of door unit 2 that faces tilt table 20. The extended position of 
carriage 30 is far enough away from tilt table 20 at least one half the 
width of door unit 2, (preferably further) so that there is clearance for 
rotation. Cylinder 60 is then actuated in the opposite direction to move 
tongue 32 back to the retracted position with support ledge 21 below 
leading end 9 of door unit 2. The operator then manually tips door unit 2 
off of props 63 and toward tilt table 20 so that it leans thereagainst. 
Following this piston 48 is actuated to operate rocker 46 to raise support 
ledge 21, transferring support of leading end 9 of door unit 2 back to 
support ledge 21. Cylinder 60 is once more actuated to move tongue 32 from 
the retracted position to the extended position in order to provide 
clearance for pivoting tilt table 20 back to the horizontal attitude. 
Piston 42 is then actuated to move tilt table 20 to the near horizontal 
attitude. Turntable 31 is then manually rotated degrees and carriage 30 
again retracted to its original position in readiness for receiving 
another workpiece. After the completion of any fabrication procedures 
desired on its upper side, door unit 2 may be moved horizontally off of 
tilt table 20 for further processing elsewhere. 
It will be seen that in the preferred embodiment of the invention the 
planate article at the near vertical attitude is still slanted from the 
vertical and thus the tilt table and against the backrests on the 
turntable of the carriage. This posture is advantageous as it avoids the 
need to provide further support at the front side of the article. However, 
if desired, the article may be supported at an essentially vertical 
posture by providing additional supports for the front side, as needed, to 
prevent the article from tipping over in the front direction. Thus, it is 
to be understood that, as used herein, the term "near vertical attitude" 
includes an attitude that is essentially vertical. Also, if desired, other 
means of transferring support between the tilt table and carriage may be 
used. Such means well within the skill of the art include providing either 
a seat on the carriage or a ledge at the leading end of the tilt table 
that is moveable vertically to effect the transfer. 
In the preferred embodiment the apparatus as depicted, articles are fed 
horizontally onto the tilt table for inversion and then moved off again 
horizontally after inversion. The apparatus of this invention may also be 
utilized advantageously for feeding articles onto and off of the tilt 
table by means of the carriage. Thus, for feeding articles, the carriage 
may be placed at its extended position with the carrier rotated to the 
position shown in FIG. 2 and the article then placed on the carrier in the 
position shown in FIG. 2, either manually or by other equipment, such as a 
fork lift. The carriage may then be retracted and the article transferred 
to the tilt conveyor for rotating it to a horizontal attitude on the 
inverter for fabrication procedures or the like. 
For feeding articles off of the apparatus, an article fed to the horizontal 
tilt table can be rotated to the near vertical and moved on the carriage 
to the extended position and rotated to the position shown in FIG. 2. Then 
the article may removed from the carrier either manually or with other 
equipment. The extended position of the carriage away from the stand 
facilitates loading or removal of the article and provides more clearance 
for the times of a fork lift.