Note: Descriptions are shown in the official language in which they were submitted.
1191~503
W- 230 POWER AND FREE CO V YOR SYSTE~MS
This invention relates to improvements in conveyor sys-
tems of the power and free type.
Such conveyor systems conventionally include a carrier
track, carriers each having a drlving trolley supported on the
carrier track, a power track spaced vertically from the carrier
track, and carrier propelling means mounted on the power track,
the propelli.ng means being normally driven in a forward direction
and including pusher members projecting toward the carrier track.
The driving trolley has a driving member which is movable between
operable and non-operable positions with respect to a pusher mem-
ber and which is biased to the operable po~ition.
Other conventional features of such conveyor systems in-
clude: ¦ j
1. The capabllity of stopping and accu~ulating carriersl
by causing their driving members to be moved to non-
operable relat.ion with the pushers; and
2. In more complex systems, the capability of providing
transfer zones to which a carrier is propelled by a
j ~orwarding pusher and from which the carrier is to
¦j be prvpelled by a receiving pusher, the forwarding
and receiving pushers usually (but not necessarily)
I . being part of separately driven forwarding and re-
i ceiving propelling means so that carrier spèed, or
relative spacing, or both, may be varied as desired
throughout the system.
Referencé is made to ~he fol]owing U. S~ patents for a
more complete disclosure of the features summarized above:
3,044,416 - The driving member of a carrier driving
trolley is connected to a forwardly projecting lever which is en-
gageable by a rearwardly projecting actuator on a preceding car-
-1~
Il. . . . I
~ 3
-230 rier to move the driving member to non-operable relation with a
pusher membQr. Bumpers on the tro]leys prevent d~mage to the
lever which ~lso serves as a counterweight to bias ~he driving
member to the operable posltion relative to a pusher member.
3,434,431 ~ A stop member, positionable in the path of
forward movement of a carrier driving trolley, contacts a cam sur-
face on the driving member to move it out of engagement with a
pusher member and is abutted by a holdback dog to stop the driv-
ing trolley. In this disclosure, a secondary stopping device is
provided to insure that the desired abutting engagement of the
stop member takes place.
3,2~9 645 and 3,314 377 - These patents relate to trans-
fer zones through which carriers are propelled by forwarding and
receiving pusher members. Each carrier is provided with a second-
ary driving member which is located rearwardly of a main driving
member and is engageable by a forwarding pusher member to advance¦
the carrier through the transfer zone. Interference between pushl
er and driving members is prevented by dimensional differences in ¦
the driving and holdback members of the carrier and in the spacing
20 ¦ between the carrier track and the forwarding and receiving power
¦ tracks.
¦ All of the results obtainable by the teachings of these
prior patents are achieved in the conveyor systems of the present
invention by a relatively less complex construction which offers
several additional constructional and operational feat~lres in-
cluding:
1. The capability of providing two types of conveyor
systems, one having the power track located below
¦ the carrier track and the other having the power
track located above the carrier track as in the
prior patents mentioned above;
1191)503
W 230 2. Transfer ~ones at which carriers can be accumulated
and through which carri~rs can be propelled by for-
warding and r~ceiving pusher members without r~-
quiring a secondary driving member on each carrier
and without interference between the carrier driv-
ing member and ~he forwarding and receiving pusher
members;
3. Stops which positively arrest forward movement of a
carrier; and
4. Carrier bumpers and accumulating mechanism which
are located within a protecked space partially en-
closed by the structural members for~ing the car-
rier track.
In a conveyor system of the invention, having the con-
ventional components described above in the second paragraph of
this specification, the driving member of the ~riving trolley in-
¦ cludes an end portion which extends from the driving trolley to-
ward the power track and which is integrally formed with a driv-
ing dog and an actuating cam, the driving dog having a driving
face engageable by a pusher member in the operable position of
the driving member, and the actuating cam extending from the driv-
ing member in the forward direction.
This actuating cam is provided with:
1. A first accumulating cam surface adap~ed to engage
l a rearwardly extending actuator on a preceding car-
¦ rier and move the driving member to non-operable
position for carrier accumulation.
2. A second stopping cam surface which is located be-
tween the first accumulating cam surface and the
j driving face of the driving dog and which extends
to an abutment formed on the drîving member for-
-3-
~ ~3~ 5~ ~
W-230 1 wardly of the driving dog. A stop member, posi-
tionable in the path of movement of the driving
member, lS engageable by the stopping cam surface
to move the driving member to non-operable position
and is engageable by the abutment to stop the car-
rier; and
3. A third anti-jam cam surface which is located out-
wardly of the abutment surface~ extends toward the
driving face and is adapted to move the driving mem
ber toward non-operable position in response to en-
gagement between the anti-jam cam surface and a
pusher member overtaken thereby, thus preventing
this type of interference between the driving and
pusher members.
Preferably, a holdback dog is integrally formed with
the driving member and has a holdback face engageable by a pusher
member in the operable position o~ the drîving member. Movement
of the driving member to non-operable posi,ion under any of the
accumulating, stopping or interference-preventing conditions de-
scribed above also results in the holdback dog being non-engage~
able by a pusher member,
Preferably also, the driving dog of the driving member
includes a pair of wing portions each projecting transversely to
one side of the actuating cam, each provided with a continuation
of the driving face of the driving dog, and each provided with a
continuation of the anti-jam cam surface. The stop member is
formed with an offset portion which is overlapped and is engage-
able by one of the wing portions to limit the movement of the
driving member that results from the engagement of the stop mem-
ber by the stopping cam surface and to thereby insure engagement
between the stop member and the abutment on the actuating cam.
~ 5~3
W-230 In a conveyor system of the invention having a transfer
zone to the entrance end of which a carrier is propelled by a
¦ forwarding pusher member whose path of travel is defined by a
forwarding power track and from the exit end of which a carrier
îs to be propelled by a receiving pusher member whose path of
travel is defined by a receiving power track, the invention -
1. Provides parallel portions of the forwarding and
receiving power ~racks, which portions are located
between the entrance and exit ends of the transfer
zone, are offset to opposite sides of a vertical
plane through the longitudinal centerline of the
carrier track, and extend parallel to that plane.
These parallel power track portions position the
forwarding and receiving pusher members in trans-
versely spaced relation so that a fo~arding pusher
member is engageable with one of the driving dog ¦
wing portions and a receiving pusher member is en-
gageable with the other of the driving dog wing
portions. At the exit end of the transfer zone one
of the forwarding and receiving power tracks di-
verges from the other and the receiving power track¦
converges into aligned relation with the centerline¦
of the carrier track~ A transfer takes place as ¦
the result o the successive engagement of the
driving dog wing portions by forwarding and receiv-
ing pusher members.
2. Provides that the dri~ing dog wing portions project
to each.s~de of the holdback face of a holdback dog
and that the parallel power track portions are so
arranged relative to the vertical plane through the
cente~line of the carrier track as to prevent en-
~ 5~ 3
W-230 gagement of the holdback face by at least one, and
pre:Eerably both, of the forwarding and receiving
¦ pusher members when positioned by the parallel power
track portions~ This eliminates the possibility of
interference between the holdback dog and a pusher
member in the transfer ~one.
3. Provides beveled surfaces on the sides of the pusher
members and on the sides of the driving dog wing
portions, the aforementioned anti-jam cam surfaces
on the driving dog wing portions, and means for ré-
latively positioning the driving dog and pusher
members so that possible engagement therebetween is
limited to engagement of the beveled and anti-jam
cam sur-Eaces, which engagement causes the driving
dog to be moved ~o a non-operable position~ The re-
lative positioning of the driving dog and pusher
members is accomplished by a cam bar mounted between
the parallel trac~ portions and engageable by the
l driving dog, or alternatively by the relati.ve ele-
vation of the carrier track to a power track.
The foregoing and other features of the invention will
be developed in the description to follow of the presently pre-
ferrea embodiments disclosed in the accompanying drawings, in
which:
FIG. 1 is a schematic plan ~iew of a representative
conveyor system illustrating features of the invention;
FIG. 2 is a side eleyation of a load carrier of a type
of conveyor system of the invention in which the power track is
located below the carrier trackj
¦ FIG. 3 is an end elevation of FIG, 2 showing the track
structure;
:
~6~
5~
W-230 FIG. 4 is an enlarged side elevation of the driving
trolley of the load carrier of FIG~ 2;
FIG. 5 is an end elevation of the trolley of FIG. 4;
FIG. 6 is a side elevation showing an accumulated rela-
tion between a trailing trolley of one carrier and a driving trol-
ley of a following carrier;
FIG. 7 is a fragmentary sectiona~ elevation taken as
indicated by the line 7-7 o~ FIG. l showing the relati.on between
the driving trolley and forwarding and receiving pushers at one
¦type of transfer;
FIG. 8 is a fragmentary side elevation further illus-
trating various relationships between the driving trolley and
pushers in the transfer of FIG~ 7;
FIG. 9 is a fragmentary sectional elevation taken as
indicated by the line 9-9 of FIG~ 1 showing the relation between I ~,
the driving trolley and forwarding and receiving pushers at
another type o~ transfer;
FI&. 10 is a fragmentary side elevation taken as indi-
l cated by the arrow 10 of FIG. 1 showing the relation between the
l driving trolley and a stop memberi
FIG, 11 is a secti.onal elevation taken as indicated by
the line 11-11 of FIG. 10;
FIG~ 12 is a plan view taken as indicated by the line
12-12 of FIG. ll; and
FIG. 13 is a side elevation of a driving trolley of the
inVention modified for use in a conveyor system of the invention
in ~hich the carrier track is located below the po~er track~ .
FIGS, 2 and 3 illustrate a conveyor system of the in-
vention in which a carrier track 10 is located above a power track
12. The carrier track 10 is formed by a pair of channel-section
track members 13 and 14 ~FIG. 3) ? the lower flanges of which pro-
~l~V503
W-~30 1 vide a pair of transversely spaced carrier supporting track sur-
faces 15 each pro~ecting toward the other rom one of the verti-
cal web portions 16 extending perpendicular to the track surfaces.
The upper flanges 18 of the track members 13 and 14 provide a
pair of opposed guide surfaces 19~
A carrier 20 is supported on the carrier track 10 and
will of course have a configuration suited for the article or
articles being handled in a particular conveyor system. The re-
presentative form of carrier shown in FIG. 2 consists of a lead-
ing driving trolley 22 ? an intermediate load carrying trolley 24
and a traillng load carrying trolley 26. A tow b~r 27 is con-
nected to the driving trolley 2~ and to the intennediate trolley
24 with universal type connections 28. Load carrying structure
30 is connected to each of the intermediate and trailing trolleys
24 and 26 by a vertîcal pivot pin 31~ ,,
Other possible carrier configurations include a carrier
having a driving trolley 22 and a trailing trolley 26 with load
supporting structure connected to either or both of these trol-
leys; and, a carrier having only a driving trolley 22 with load
carrying structure connected thereto. Any carrier will include a
dri~ing trolley 22, regardless of what other carrier components
may be employed.
¦ The power track 12 is spaced vertically from the car-
l rier track 10 and, as showTl in FIG. 3 consists of a pair of
I channel-section track members 32 and 33 mounted in a transversPly
spaced toe-to-toe relation which is normally symmetrical to a
vertical plane 34 extending through the longitudinal centerline
¦ of the carrier track 10. Structural frames 36 support the car-
rier and power tracks 10 and 12 at longitudinally spaced inter-
vals as shown in FIG, 2. Each frame 36 consists of a pair of
vertical channel section supports 37 for thP carrier track mem-
~ 3
W-230 bers 13 and 14, a transverse angle section m~mber 38 joined to the supports 37 and to the power ~rack members 32 and 33, and a
base member 39 which is secured to each of the other components
of the frame 36 and may be mounted on any suitable foundation at
any elevation desired~
Carrier propelling means 40 (FIG. 2) are mounted on the
power track 12, are normally driven in a forward direction as
indicated by the arrow 41, and include pusher members 42 project- ¦
ing toward the carrier track 10. In the particular construction
shown, the pusher members 42 are formed on links 43 of an endless
chain 44 connected to power trolleys 45 which travel on the power
track 12. Other forms of propelling means conventionally employ-
ed in power and free conveyor systerns can also be used.
Referring to FIGS. 2, 4 and 5, the driving trolley 2~
has a driving member 46 movable bet~een operable and non-operable
positions with respect to a pusher member 42, and biased to the
operable position shown in FIG. 2 and in solid line in FIG. 4.
The driving member 46 includes an end portion 48, which extends
from the driving trolley 22 toward the power track 12, and a stem
I portion 50 which is movably mounted within the driving trolley
body 52 by suitable means to be described~
The trolley body 52 comprises a pair of transversely
spaced, interconnected side plates 54 having wheel supporting
portions 55 di.sposed within the carrier track 10 and carrying
portions 56 disposed externally of the carrier track. Apertures
57 are provided in the portions 56 for connecting the tow bar 27
or load carrying structure to the trolley body. Front and rear
axles 58 and 59 extend between the poxtions 56 with a pair of
front and a pair of rear load carrying wheels 60 and 61 being
mounted on the axles 58 and 59, respective~y. Spacers 52
(FIG, 5) position ~he wheels 6Q and 61 outwardly of ~he side
1~905(33
-230 pla~es 54. The tread dimension between each pair of wheels is
considerably greater than normal practice for free ~rolleys of
power and free conveyor systems, and requires a corresponding in-
crease in the transverse spacing between the carrier track mem-
bers 13 and 14. Front and rear guide rollers 63 and 64 are each
mounted on a stub axle 65 secured to a block 66 interconnected~
between the carrying portions 56 of the side plates 54. Each of
the guide rollers 63 and 64 is engageable with ~he guide,surfaces
19 of the carrier track members and h~s~a diameter corresponding
to the increased spacing between these guide surfaces and corres-
ponding substantially to the diameter of the wheels 60 and 61.
The dimensional increases in the transverse spacing be-
tween the carriPr track members 13 and 14, the tread of the load
carrying wheels 60 and 61, and the diameter of the guide rollers
63 and 64 result in improved lateral stabilit~ which is particu-
larly advantageous in conveyor systems of th~ type shown in FIG. 2
ha~ing the platorm~1ike article carrying structure 3~ located
above the carrier track 10.. The latera~ stability of the struc-
ture 30 may be maintained solely by the engagement between the
~0 trolleys 22 and 24 and the carrier track supporting surfaces 15
and guide surfacPs 19. These dimensional increases, in the case
of the driving trolley 22, also contribute to several other ad-
vantages resul~ing primarily ~ro~ the construction of the driving
member 46.
As shown in FIGS. 4 and 5, the stem portion 50 of the
¦ driving member 46 is movably mounted between th~ trolley body
side plates 54 and between longitudinally spaced guides consist- .
ing of a roller bushing 67 on the front axle 58 and a guide por-
tion 68 of a web 6~ which interconnects the side plates 54. The
inner end 70 of the stem portion is connected to an arm 71 car-
ried by a pivot pin 72 mouTIted between the side plates~ The
driving member 46 of the trolley of FIGSr 4 and 5 is biased to
~ 3
I .-230 the operablc position by its weight, and the arm 71 serves pri-
marily to define this position by engaging an abutment 73 on the
trolley body.
The end portîon 48 of ~he driving member 46 is integral-
ly formed with a driving dog 74 and an actuating cam 76, the driv-
ing dog 74 having a driving face 75 engageable by a pusher 42 in
¦the operable position of the driving member and the actuating cam
76 extending from the driving dog in the forward direction 41. A
holdback dog 78 is also integrally formed with the driving member
46 in the construction shown and has a holdback face 79 engageable
by a pusher 42 in the operable position of the driving member;
however, the holdback face projects outwardly less than the driv-
ing face 75 and is of limited width, as shown in FIG. 5. Provided
on the actuating cam 76 are a first accumulating cam surface 80 J a
secondstopping cam surace 81, and a third anti-jam cam surface 82 .
The accumulating cam surface 80 is located at the for-
ward end of the actuating cam 76 wllich projects within the web
portions 16 of the carrier track members 13 and 14. As shown in
FIGS. 2 and 6, each carrier is provided with a rearwardly extend-
ing actuator 84 adapted to be engaged by the accumulatlng cam
surface 80 of a following carrier for moving the driving member
46 of the following carrier to the non-operable position shown in
full line in FIG. 6. Complementary retaining surfaces 85 of the
accumulating cam 80-and 86 of the actuator 84 maintain the driv-
ing member 46 in this position.
Each carrier is also provided with a forwardly project-
ing bumper 87 and a rearwardly projecting bumper 88 located within
the w~b portions 16 of the carrier track members 13 and 14. As
illustrated in FI~. 6, the rearwardly projecting bumper 88 of one ¦
carrier is engageable by the forwardly projecting bumper 87 o a
following carrier when the driving member 46 of ~he following
30503
W-230 carrier has been moved to the non-operable position in response
to the engagement of the actuator 84 of the one carrier by the
accumulating cam surface 76 of the following carrier. The retain-¦
ing surfaces 85 and 86 are so arranged that the driving member is
in non-operable position prior to engagement of the bumpers 87
and 88.
FIGS, 2 and 6 illustrate the manner in which the actuat-
or 84 and the bumpers 87 and 88 are installed on the mul~iple-
trolley carrier 20. The forward bumper 87 is mounted on the body
52 of the driving trolley 22; while the actuator 84 and rearward
bumper 88 are mounted on the body of the trailing trolley 26
(and optionall~ also on the body of th~ intermediate trolley 24,
as shown in FI~ 2, if a maximu~ density accumulation zone is de-
sired~. In a conveyor system having carriers each including only
la single driving trolley, an actuator 84 and a rearward bumper 88
would be mounted on the body of each such driving trolley.
The second stopping cam surface ~1 of the actuating
cam 76 is located between the firs~ accumulating cam surface 80
and the driving face 75 of the driving dog and extends to an abut-
ment surface 90 formed on the driving member 46 forwardly of the
driving dog.- In the operable position of the driving member shown
in FIG. 4, the stopping cam sur~ace 81 is located ext~rnally of
the carrier track 10 and functions in the manner sho~ in FIGS.
10-12. A stop member 91 (movable transversely of th~ carrier
track 10 in the known manner2 is posltionable in the path of move-
ment of the end portion 48 of the driving member 46, is engage-
able by the stopping cam surfac~ 81 to move the driving member to
non-operable position as shown in FIG~ 11, and is engageable by
the abutment surface 90 as shown in FIGS. 10 and 12 to stop the
carrier. When the holdback dog 78 is integrally formed with the
driving member 46, that dog also becomes non-engageable by a
~ S~ 3
W-230 ~¦pusher member 42 when the driving member 46 is moved to non-oper-
¦able position by the stop member 91~ The abutment surface 90 pro-
jects to each side of the holdback face 79 to prevent interference
of theholdback face with the stop member 91 when it is disengaged.
The third anti-jam cam surface 82 of ~he actuating cam
76 is located outwardly of the abutment surface 90 and extends
¦toward the driving face 75 of the driving dog. This anti-jam cam
¦surface 82 is adapted to move the driving member 46 toward non-
loperable position in response to engagement between the anti-jam
cam surface 82 and a pusher member 42 overtaken thereby, which
~engagement may occur, for example, at a transfer zone.
, The driving dog 74 of the driving member 46 is prefer-
~ably provided with a pair of integral transversely extending wing
portions 92 and 93. Each of these wing portions project to one
side of the driving member and project from the ac~uating cam
rearwardly and outwardly of the abutment surface 90. Each wing
portion 92 and 93 is provided with a continuation of the driving
face 75 and with a continuation o~ the anti-jam cam surfacP 82.
Each wing portion ~2 and 93 also projects to one side of the hold-
2Q back dog 78. These ~ing portions coact with stop members 91 and ¦
with pushers 42 at a transfer zone.
Referring again to FIGS. 10 12, the stop member 91 is
formed with an offset portion 94 which extends forwardly and to
one side of the stopping surface 95 of the stop member. The for-
ward extent of the offset portion 94 is such that as the driving
member 46 is moved to non operable position in response to engage-¦
ment of the stop member 51 by the stoppin~ cam surface 81, the
offset portion 94 is overlapped and is engageable by one of the
wing portions 93 of the driving dog 74. Movement of the driving
member 46 is thereby limited and engagement of the stopping sur-
face 95 of the stop member 91 by the abutment surface 90 of the
driving member 46 is insured.
The coaction between the wing portions 92 and 93 o the
-13-
W-230 driving ~ember 46 and pushers 42 will be descr:ibed in connection
with the conveyor system schernatically shown in FIG. 1. In this
syste~, which is not intended to represent any particular system
¦ but to merely illustrate the manner in w-nich the present inven-
¦ tion is used, the path of the carrier track 10 appears as a solid
line. A carrier travelling around the system in a clockwise dir-
ection and located on the vertical line at the left hand side of
FIG~ 1, is propelled by a pusher mem~er 42-1 of a chain driven
¦ by a drive unit 96-1 and travelling in a path defined by a power
¦ track 12-1 represented in broken line. The relation between the
carriPr ~rack 10 and the power ~rack 12-1 along this portion of
the system is the normal one shown in FIGS, 2-5, the pusher and
driving members being symmetrical to the vertical plane 34 throug~
¦ the longitudinal centerline of the carrier track 10 and the pushe~
¦ member being engageable with the driving and holdback faces 75
¦ and 79 of the driving and holdback dogs 74 and 78 of the driving
member 46.
As the carrier proceeds to the right on the upper hori-
zontal track line of FIG. 1, it enters a transfer zone 98-1 to
which it is propelled by a pusher member 42-1 (acting as a for-
warding pusher member? and from which it is to be propelled by a
pusher member 42-2 (acting as a receiving pusher) of another chai¦
independently driven by a drive unit 96-2 and travelling in a path
defined by a power track 12-2~ The transfer zone 98-1 has an
entrance end ~9, and an exit end 100~ At the entrance end 9~
there is an ofsetlOl in the forwarding power track 12-1 to one
side of the vertical plane 34, and a convergence 102 of the re-
ceiving power track 12-2 relative to the vertical plane 34. Be-
tween the entrance end 99 and the exit end 100, the forwarding
and receiving power tracks 12~1 and 12-2 have parellel portions
which, as shown in FIG. 7, are offset to opposite sides of the
-14-
~ 33
W-230 vertical plane 34, ex~end parallel thereto, and preferably are
ar~;anged in substan~ially syn~etrical relation therewith. These
parallel power track portions position the forwarding and receiv-
ing pusher members 42-l and 42-2 in a transversely spaced rela-
tion at which a fon~arding pusher member 42 1 is engageable with
one of the driving dog wing portions 93 and a receiving pusher
member is engageable with tne other of the driving dog wing por-
tions 92. At the e~it end 100, the forwarding power track 12-1
diverges from the receiving power track 12-2 which converges into
the normal vertically aligned relatîon with the carrier track lO.
In~erference and jamming conditions between the driving
member 46 of a carrier and the forwarding and receiving pusher
members 42-1 and 42-2 are positively prevented by the following
features:
1. The wing portions 92 and 93 of the driving dog 74
project to each side oE the holdback face 79 of the
holdback dog and the forwarding and receiving push-
ers 42~1 and 42-2 are non~engageable with the hold-
back face 79 when positioned in transversely spaced
relation by the parallel forwarding and receiving
~rack portions.
2. The side faces 103 of the pusher members 42-1 and
42-2 are each formed with a beveled surface 104
(FIG. 7), and a complementary beveled surface 105
i5 formed on the side face 106 of each wing por-
- tion 92 and 93 of the driving dog. Lateral inter-
¦ ~erence, which could take place between the driving
dog 74 and a receiving pusher 1.2-2 at the converg-
ence 102 of the receiving track relative to the
vertical plane 34, is prevented by the engagement of
the beveled suraces 104 and 105 which are adapted
W 230 ¦ to move the driving member to non-operable position.
Positioning means relatively locates the driving
dog and receiving pusher member vertieally so that
any lateral engagement bel-ween ~hem is limited to
the beveled surfaces 104 and 105. This positioning
means, in the transfer zone construction of FIGS.
7 and 8, comprises a cam bar 107 which is suppor~ed
sy~etrically to the vertical plane 34 by the power
tracks 12-1 and 12-2, extends from the entrance end
¦ 99 to the exit end 100 of the transfer zone, is
engageable by the driving dog 74, and moves the
driving member 46 from the full line to the broken
line position shown in FIG. 8~
3. The cam bar 107 also limits any overta~ing engage-
ment between the driving dog and the forwarding and
receiving pusher members 42-1 and 42-2 to the anti-
¦ jam cam surface 82.
¦ As a result-of the foregoing features the drive units
96-1 and 96-2 do not require any synchroni~ation or interlock con-
trols and can be operated at any desired spaced differential.
Should the driving member of a carrier, being propelled in the
transfer zone 98-1 by a pusher member on either the forwarding
power track 12-1 or the receiving power track 12-2, engage a
slower moving pusher member on the other power track, the driving
member 46 will simply disengage and will be re-engaged by the
next pusher member until the carrier clears the exit end lQ0.
Should the driving member engage a stopped receiving pusher mem-
ber, the same disengagement of the driving member 46 will vccur
¦ but the carrier will not clear the transfer zone until the receiv-
30ing pusher members are again moving. Any following carriers will
accumulate behind ~he stopped carrier. If desired, ~he transfer
~l~q.
~ 5~
W-230 zone can be made a part of the system where carrier.s are accumu
lated by providing a stop member 91 at the exit side of, or even
in the transfer zone ~8~1.
Referring again to FIG, 1, from the transfer zone 98~1
a carrier proceeds through a processing station 108 and to a
second transfer zone 98-2. This zone is the same as the zone
98-1 except that a pusher member 42~2 acts as the forwarding push-
er member and a pusher member 42-1 acts as the receiving one. The
carrier is then advanced to a ~ransfer zone 10~-1 where a branch
carrier track lO-l connects with the main carrier track lO through
a switch 110. The power track 12-1 follows the branch carrier
track 10-1 to a re-entry transfer zone 109-2, passes through a
change in elevation at 111 and returns to the transfer zone 109-1
along the path 112 and eleva~ion change 114. The transfer zones
109-1 and 109-2 illustrate an arrangement frequently employed in
power and free conveyor systems where all the pusher members in-
~olved in a transfer are on the same chain, with one pusher mem- ¦
ber 42-1 acting as a forwarding pusher member and another pusher
member 42-1 acting as a rece~ving pusher member.
FIG. 9 schematically illustrates an alternative posi-
j tioning means to the cam bar 107 for relatively locating the driv-
¦ ing dog and pusher members vertically at the transfer zone lO9-1
where a pusher member 42-lF is forwarding and a pusher member
42-lR is receiving~ Since these pusher members are on the same
chain and are moving at the same speed, the only possible inter~
ference is the lateral interference that may occur at the converg-
ence 115 of the receiving pusher at the entrance end of the trans-
fer zone. Positioning is accomplished by arranging the structure
supporting the power track of the receiving pusher 42-lR at an
~ elevation relative to the carrier track 10 such that lateral en-
gagement betwe,en the driving dog wing portion 93 and a receiving
-17~
1190503-230 ~pusher ~ember 42-lR is limited to the engagement of the beveledsurfaces 104 and 105, at least in the region of the convergence
115. If such engagement should occur, the driving member 46 will
be moved toward the non-operative position a distance sufficient
to clear the receiving pusher 42-lR but not sufficient for the
driving dog wing portion ~2 to disengage from the fo~arding push-¦
¦er member 42-lF.
The arrangement of FIG. 9 can be used at the re-entry
transfer zone 109-2 except that here the convergence is ln, and
the positioning means would be exmployed for, the power track
¦12-1, which does not support the receiving pusher members.
¦ Both of the forwarding and receiving power tracks may
be supported to position their respective pusher members at the
ve~tical elevation of-the pusher member 42-lR of FIG. 9 for the
same results obtainable with the cam bar 107 of FIGS. 7 and 8.
Another preferred feature shown in FIGS. 7 and 9 is that
the wing portions 9~ and ~3 are disposed within an operational area
bounded by vertical planes through the transverse extremities of
the carrier tr~ck members 13 and 14, and that the employment of
parallel track members 32 and 33 for the power tracks enables the
forwarding and receiving pusher members to be disposed within ~.hi5
area; thereby simplîfying the track supporting structure.
FIG. 13 illustrates a carrier driving trolley 122 of the
¦invention for an o~erhead power and ~ree conveyor system having
the power track mounted above the carrier track 10. The trolley
122 is essentially the same as the driving trolley 22 except that
a lever 116 is employed in place of the arm il and is provided
with a counterweight portion 118 adapted to bias the driving mem-
ber 46 to the operative position sho~n relative to a pusher mem-
~ber 42
~ -18-
