Vacuum assisted stick placer

A vacuum assisted stick placer for (a) retrieving a spacing stick from a J-hook on a J-hook stick conveyor, whereon a first broad side of the stick is supported on the J-hook, and (b) placing the stick onto a top surface of a stack of lumber has a selectively actuable vacuum gripping device for (a) selectively applying a vacuum to the first broad side of the stick whereby the stick may be adhered to the vacuum gripping device when the vacuum gripping device is in a stick retrieving position snug beneath the first broad side of the stick supported in the J-hook, and (b) selectively removing the vacuum from the first broad side of the stick whereby the stick may be released from the vacuum gripping device, when the vacuum gripping device is in a stick placing position substantially opposed to the stick retrieving position and proximate the top surface of the stack of lumber, a first translation device for rotatably translating the vacuum gripping device in an arcuate path and a second translation device for substantially linearly translating the vacuum gripping device in a radial direction from the arcuate path, the first and second translation devices translating the vacuum gripping device between the stick retrieving position and the stick placing position, a support frame for supporting the first and second translation devices over the stack of lumber, whereby a second broad side of the stick opposed to the first broad side may be placed into contact with the top surface of the stack of lumber.

FIELD OF THE INVENTION 
This invention relates to the field of stick placer apparatus and, in 
particular, to spacing stick retrieval and depositing mechanisms within 
such apparatus wherein retrieval is from conventional J-hook stick 
conveyors. 
BACKGROUND OF THE INVENTION 
Spacing stick placer apparatus are used to place spacing sticks between 
stacked tiers of green lumber. The sticks serve to provide space between 
the tiers of lumber to allow air flow for either kiln drying or air 
drying, as well as to stabilize the tiered lumber package. Typically, 
spacing stick placer apparatus are used in conjunction with lumber 
stackers that stack the green lumber in tiers, the stick placer apparatus 
conventionally being placed over the lumber stacker. The sticks are placed 
in spaced parallel array across the width of the lumber tiers, the sticks 
aligned perpendicular to the long dimension of the lumber. The number of 
sticks so placed depends upon the length of the lumber and the desired 
spacing between the sticks. In modern sawmill practices it is desired that 
the first and last stick of the array of sticks placed onto a tier of 
lumber be placed flush with the ends of the lumber. It is also desired 
that a stick placer be able to accomodate lumber of difference lengths. 
It is conventional for sticks to be conveyed over the lumber stack from a 
stick allocating device by means of a continuous chain from which depend 
spaced apart hooks. The spaced apart hooks are "J" shaped so as to receive 
and support a single stick per hook. The "J" shaped hooks, hereinafter 
J-hooks, are translated past the stick allocating device on the continuous 
chain. An opposed pair of J-hook continuous chains co-operate with the 
stick allocating device so that opposed pairs of J-hooks receive single 
sticks from the stick allocating device and convey those sticks along the 
continuous chain over the lumber stack. The chains move linearly along an 
opposed pair of tracks supported above the lumber stack, the tracks 
supported conventionally by a support frame. The J-hook continuous chains 
are supported at either end of the opposed pair of tracks by sprockets, 
one of which is conventionally a drive sprocket, the other an idler 
sprocket. 
Applicant is aware of prior art spacing stick depositing devices used in 
conjunction with conventional J-hook continuous chains, notably, Rysti, 
U.S. Pat. No. 3,823,834 which issued Jul. 7, 1974 for a "Method and Device 
for Performing the Insertion of Piling Strips in Timber Packages". The 
Rysti U.S. Pat. No. '834 method and device first stops the stick conveyor, 
then carrying hooks mounted on an elevated frame removes the sticks from 
the stick conveyor. The elevating frame is then lowered to the uppermost 
lumber tier where the sticks are pushed off the carrying hooks by a 
plurality of fingers so as to deposit the sticks on the lumber tier. 
Applicant is also aware of Rysti, U.S. Pat. No. 4,360,303 which issued Nov. 
23, 1982 for a "Method and Apparatus for Locating Spacer Strips between 
Layers of Timber Packages". The Rysti U.S. Pat. No. '303 method and 
apparatus also stops the stick conveyor at an appropriate position over a 
lumber stacks. The sticks are guided down onto the top surface of the 
uppermost tier of lumber by a plurality of free-fall depressors or 
plungers. 
Applicant is further aware of Dion et al, U.S. Pat. No. 5,244,341 which 
issued on Sep. 14, 1993 for a Lath Placer. Dion et al teaches placing lath 
binders and stickers onto stacks of lumber using a rotating vacuum 
assisted delivery system for retrieval of lath from a curved magazine. A 
selectively actuable vacuum is applied to adhere the lath to the rotating 
delivery arm. Rotation of the delivery arm releases the lath onto the top 
surface of a lumber tier upon the selectively actuable vacuum being 
removed to allow the lath to fall, on edge, from the rotating arm. 
It has been found that because spacing sticks or stickers are significantly 
thicker than lath, the Dion et al device will not necessarily place sticks 
flat but may place them so that they remain standing on edge. Further, it 
has been observed that dropping sticks from the transfer arm of the Dion 
et al device results in inaccurate placement of the sticks onto the stack 
of lumber. This is particularly problematic when attempting to place 
spacing sticks at the ends of the stack of lumber as the sticks may fall 
from the stack of lumber. 
Consequently it is an object of the present invention to provide a device 
for the positive placement of spacing sticks onto a stack of lumber. In 
this regard Applicant is aware of U.S. Pat. No. 4,801,233 which issued to 
Ritola on Jan. 31, 1989 for a "Sticker Placer Apparatus" which teaches a 
device for the positive placement of spacing sticks onto a stack of 
lumber. Sticks are fed from a stick conveyor into inclined stick feeding 
pockets, the stick feeding pockets indexing individual sticks into the 
grip of actuable stick supporting and pinching arms rotatably mounted at 
the lowermost end of vertically translatable placement plungers. The 
vertical position of the placement plungers, and thus the position of the 
stick supporting and pinching arms, is governed in the Ritola device by an 
actuating arm releasing or increasing the tension on a flexible chain 
extending between the stick supporting and pinching arms and the actuating 
arm. Positive placement of a stick from the supporting and pinching arms 
is accomplished when the lowermost end of the vertically translatable 
placement plunger engages the top surface of a stack of lumber. Continuing 
detensioning of the flexible chain by the actuating arm allows the 
rotatably mounted stick support arm to rotate under the return biasing 
force of a resilient spring so as to deposit the stick from the support 
arm onto the stack of lumber. 
In view of the complexity of the Ritola device, and in view of the fact 
that applicant is aware that the Ritola device is prone to jamming, it is 
an object of the present invention to provide a simple apparatus which may 
be retrofitted onto the support frames of conventional J-hook stick 
conveyors for the positive and accurate placing of spacing sticks onto a 
stack of lumber. Consequently a vacuum assisted stick retrieval and 
placement device is provided having two degrees of freedom, namely, a 
first radial or linear translation and a second rotational translation of 
a vacuum assisted stick gripping head. 
SUMMARY OF THE INVENTION 
There are two preferred embodiments to accomplish the removal of a spacing 
stick from horizontal carriage in a conventional J-hook stick conveyor and 
positive placement of that stick horizontally onto the top surface of a 
stack of lumber. The present device provides that a spacing stick may be 
placed flush with the top surface of the stack of lumber so as to rest on 
one of its opposed broad sides, rather than on edge, on the lumber stack. 
In particular, the present device provides a device for accurate stick 
placement at the ends of the stack of lumber. 
The present invention provides a vacuum gripping head which may be adhered 
by vacuum to the underside of a spacing stick carried horizontally in a 
J-hook stick conveyor. A vacuum is applied between the vacuum gripping 
head and the lower broad side of the stick. To place the vacuum gripping 
head into position so as to retrieve the spacing stick from the J-hooks 
supporting the spacing stick in the J-hook stick conveyor, hereinafter the 
stick retrieval position, the vacuum gripping head must be elevated into 
contact or at least close proximity to the lower broad surface, that is, 
the undersurface, of a spacing stick held horizontally in the J-hooks. 
When the vacuum gripping head is in its stick retrieval position and has 
been adhered to the lower broad surface of the spacing stick held 
horizontally in the J-hooks, the spacing stick may be removed from the 
J-hooks in a substantially horizontal plane so as to clear the spacing 
stick from the supporting arms of the J-hooks as the J-hooks continuously 
translate over the lumber stack. The spacing stick may then be lowered to 
the stack of lumber so as to place the spacing stick with a broad side 
down, as opposed to placing the spacing stick with an edge of the spacing 
stick in contact with, or in close proximity to, the top surface of the 
stack of lumber. With the spacing stick and the vacuum gripping head 
thereby in a stick placing position, the vacuum adhering the spacing stick 
to the vacuum gripping head may be removed so as to leave the spacing 
stick properly positioned on the top surface of the stack of lumber. 
The translation between the stick retrieving position and the stick placing 
position is accomplished in the present invention by coupling an arcuate 
translator, that is, a rotational translation of the vacuum gripping head, 
with a linear translation of the vacuum gripping head in a direction 
radial to the centre of rotation of the rotational translation.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
In a first embodiment, as illustrated in FIGS. 1a-1d, spacing stick 10 is 
vacuum adhered to vacuum arms 12 at vacuum gripping heads 14 when vacuum 
arm 12 and vacuum gripping heads 14 are in the stick retrieving position. 
Spacing stick 10 may thus be removed from J-hook stick supports 16 
(hereinafter J-hooks 16) and in particular removed from a position resting 
on J-hook horizontal support arms 16a better seen in FIG. 2. Once spacing 
stick 10 is removed from J-hooks 16, spacing stick 10 may be lowered from 
J-hooks 16 by linear translation of vacuum gripping heads 14 and spacing 
stick 10 in direction A' from the stick retrieving position illustrated in 
FIG. 1a to the intermediate stick supporting position illustrated in FIG. 
1b. Translation in direction A' is accomplished by retracting flexible 
actuators 18 into flexible actuator casings or conduits 20. Flexible 
actuators 18 are retracted by the retraction of ram cylinder 22 into ram 
cylinder housing 24. 
Vacuum gripping heads 14 and spacing sticks 10 may be rotated from the 
intermediate supporting position illustrated in FIG. 1b into the 
intermediate supporting position illustrated in FIG. 1c by rotating vacuum 
arms 12 on pivot arm 26 in direction B. Pivot arm 26 is rotated in 
direction B by the action of actuable ram cylinder 28 rotating drive chain 
30 about sprockets 32 on pivot arm 26, better illustrated in FIG. 2. 
Vacuum gripping heads 14 and spacing sticks 10 may be lowered from the 
intermediate support position illustrated in FIG. 1c to a lowered stick 
placing position illustrated in FIG. 1d. Vacuum gripping heads 14 and 
spacing sticks 10 are translated in direction A" so as to bring spacing 
sticks 10 into contact or close proximity with upper surface 34a of lumber 
stack 34 by extending ram cylinder 22 from within ram cylinder housing 24 
so as to extend flexible actuators 18 from flexible actuator casings or 
conduits 20. 
With spacing sticks 10 in contact or close proximity with upper surface 34a 
of lumber stack 34, the vacuum may be released by allowing atmospheric air 
into, for example, vacuum manifold 36 so as to release spacing sticks 10 
from vacuum gripping heads 14. Spacing sticks 10 are thereby accurately 
placed onto upper surface 34a of lumber stack 34. As also illustrated in 
FIG. 3, the vacuum is communicated to vacuum gripping heads 14, and in 
particular to vacuum orifice 14a (see FIG. 4b), from vacuum manifold 36 
via vacuum conduit 38 and extends within or communicates with a hollow 
cavity 26a within pivot arm 26 and flexible vacuum hoses 40. 
Vacuum is supplied to vacuum manifold 36 via, for example, vacuum port 39 
from a vacuum source, not shown, of a type well known in the art. In order 
to equalize, that is evenly distribute, the vacuum applied through vacuum 
orifices 14a, more than one vacuum port 39 may be incorporated along 
vacuum manifold 36. In addition, the sizes (i.e. diameter, length and 
volume capacity) of the vacuum orificies within flexible vacuum hoses 40, 
pivot arm 26, vacuum manifold 36, and vacuum conduits 38, may be varied to 
equalize the vacuum applied through vacuum orifices 14a on the array of 
vacuum gripping heads 14 spaced along, and co-operating with, vacuum 
manifold 36. Vacuum shut off valve 37 may be provided between vacuum 
manifold 36 and vacuum conduit 38. 
It is understood that the rotational and linear translations of spacing 
sticks 10 and vacuum gripping heads 14 in directions A', B and A" 
illustrated in FIGS. 1a, 1b and 1c may be simultaneous as illustrated in 
FIGS. 4a-4c. Thus gripping heads 14, flexible actuator 18, flexible 
actuator casings or conduits 20 and flexible vacuum hoses 40 may be 
rotated in direction B simultaneously with gripping heads 14 being 
retracted in direction A' and subsequent extention in direction A". 
As illustrated in FIGS. 5, 6 and 7 continuous J-hook stick conveyor 42 
conveys sticks 10 in J-hooks 16 in direction C. J-hooks 16 are mounted on 
continuous chain 44. Continuous chain 44 runs inside channel guides 46 and 
around sprockets 48. It is understood that a stick allocator (not shown) 
would conventionally load individual spacing sticks 10 onto J-hooks 16. 
One of sprockets 48 will conventionally be a drive sprocket driven for 
example by drive axle 50. 
Finger-like protrusions 52 are provided to assist vacuum arm 12 in removal 
of spacing sticks 10 from J-hooks 16. Finger-like protrusions 52 may be of 
resilient wire as illustrated. Finger-like protrusions 52 may be securely 
mounted to vacuum arm 12 on the downstream side of vacuum arm 12 relative 
to direction C movement of J-hooks 16 on J-hook stick conveyor 42. Thus 
when vacuum arm 12 is raised into its stick retrieving position, 
finger-like protrusions 52 engage spacing sticks 10 so as to push spacing 
sticks 10 from J-hook support arms 16a thereby assisting vacuum gripping 
head 14 in removing spacing stick 10 from J-hook 16. 
Limit switches of a type known in the prior art, such as telescoping limit 
switches 54, may be provided to cut-off ram cylinder 22 when one or more 
of limit switches 54 contact upper surface 34a of lumber stack 34. A 
triggering of one of more limit switches 54 could either cut-off single 
ram cylinder 22 (i.e. the cylinder 22 directly corresponding to that 
switch 54) or a plurality of ram cylinders 22 actuating the array of 
actuators 18. Limit switches 54 enable flexible actuators 18 to be 
extended until positive contact with upper surface 34a of lumber stack 34 
is made, and thus take into account irregularities from warped boards and 
the like on upper surface 34a. 
A second embodiment of the present invention is illustrated in FIGS. 8-13. 
As illustrated in FIG. 8a, spacing stick 10 is gripped by vacuum arm 12' 
at vacuum gripping head 14' when vacuum arm 12' and vacuum gripping heads 
14' are in the stick retrieving position. Spacing stick 10 may thus be 
removed from J-hook stick supports 16 and in particular removed from a 
position resting on J-hook horizontal support arms 16a better seen in FIG. 
10. Once spacing stick 10 is removed from J-hooks 16, and spacing stick 10 
is adhered by means of vacuum to vacuum gripping head 14', vacuum arm 12' 
may be rotated on pivot arm 26' in direction D so as to pass through the 
intermediate rotated position illustrated in FIG. 8b into the rotated 
position illustrated in FIG. 8c substantially rotated 180 degrees from the 
stick retrieving position of FIG. 8a. From the rotated position 
illustrated in FIG. 8c, vacuum arm 12', still gripping spacing stick 10 at 
vacuum gripping head 14', may be lowered by swing arms 56 and 56' so as to 
bring spacing stick 10 into contact or close proximity with top surface 
34a of lumber stack 34. As illustrated in FIG. 8c and FIGS. 9a-9c, swing 
arms 56 and 56' translate vacuum arm 12' substantially vertically in 
direction E. 
Pivot arm 26' is rotated in direction D by actuable ram cylinder 28' 
rotating drive chain 30' about sprockets 32' on shaft 58. Shaft 58 is 
rotatably journalled through rotatable collar 60 so as to rotate secondary 
drive chain 62 thereby engaging and rotating pivot arm 26'. The ends of 
pivot arm 26' are rotatably journalled in swing arms 56 and 56'. 
Swing arm 56 is rigidly mounted to rotatable collar 60. Also rigidly 
mounted to rotatable collar 60 is linkage 64. Actuable ram cylinder 66 is 
rotatably connected to rotatable collar 60 via linkage 64 so that 
actuating ram cylinder 66 rotates linkage 64, rotatable collar 60, swing 
arm 56, pivot arm 26', vacuum arm 12' (including vacuum gripping head 
14'), and swing arm 56' in direction F so as to thereby lower or raise in 
directions E and E' respectively vacuum gripping head 14' and spacing 
stick 10. 
It is understood that translations D, E and F, as illustrated in FIGS. 
8a-8c and FIGS. 9a and 9b, may be simultaneous. Thus vacuum gripping head 
14' holding spacing stick 10 on vacuum arm 12' may be simultaneously 
rotated in direction D and lowered in direction E so as to bring spacing 
stick 10 into contact or close proximity with top surface 34a of lumber 
stack 34. 
As illustrated in FIG. 9c, the vacuum applied between vacuum gripping head 
14' and spacing stick 10 through vacuum nozzle 68 may be released to place 
spacing stick 10 onto top surface 34a of lumber stack 34. It is understood 
that vacuum nozzle 68 may be an elongated slit or orifice on vacuum 
gripping head 14' or an array of orifices on vacuum gripping head 14'. The 
vacuum applied between spacing stick 10 and vacuum gripping head 14' 
through vacuum nozzle 68 is communicated to vacuum nozzle 68 from vacuum 
manifold 36' through hollow vacuum arm 12', hollow pivot arm 26', hollow 
swing arm 56', and vacuum conduit 38'. Once the vacuum is released from 
vacuum nozzle 68 and spacing stick 10 left on top surface 34a of lumber 
stack 34, vacuum arm 12' may be retracted from its stick placing position 
vertically upwards in direction E' to raise finger-like protrusions 52' 
above spacing stick 10 and therafter raised vertically in direction E' 
while being rotated in direction D' so as to be repositioned under J-hook 
stick conveyor 42. Another spacing stick 10 may then be selectively 
retrieved from J-hooks 16 as J-hooks 16 carrying spacing sticks 10 are 
conveyed in direction G. 
Illustrated in FIGS. 10-12 is the manner in which vacuum arm 12" may be 
bent or canted so as to offset a spacing stick 10 from the spacing 
otherwise employed between individual vacuum arms 12'. The bent or canted 
vacuum arm 12" allows accurate placement of a spacing stick 10 along the 
end edges of top surface 34a of lumber stack 34. 
Finger-like protrusions 52' are provided to assist vacuum arm 12' in 
retrieval of spacing sticks 10 from J-hooks 16. Finger-like protrusions 
52' may be of resilient wire design as illustrated. Finger-like 
protrusions 52' are securely mounted to vacuum arm 12' on the downstream 
side of vacuum arm 12' relative to direction G movement of J-hooks 16 on 
J-hook stick conveyor 42. Thus when vacuum arm 12' is raised into its 
stick retrieving position, finger-like protrusions 52' engage spacing 
sticks 10 so as to push spacing sticks 10 from J-hook support arms 16a 
thereby assisting vacuum gripping head 14' removing spacing stick 10 from 
J-hook 16. As described above with respect to the first embodiment of the 
present invention, limit switches may be incorporated on the second 
embodiment and in particular, although not illustrated, telescoping limit 
switches 54 might extend beyond, and parallel to, fingerlike protrusions 
52' from vacuum arm 12'. 
As will be apparent to those skilled in the art in the light of the 
foregoing disclosure, many alterations and modifications are possible in 
the practice of this invention without departing from the spirit or scope 
thereof. Accordingly, the scope of the invention is to be construed in 
accordance with the substance defined by the following claims.