Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND AND SUMMARY OF THE INVENTION
This invention pertains to side shifters used on
lift truck carriages, and more particularly to bearings
employed to facilitate transverse movement of a side shifter
on the carriage.
Fork lift trucks have found wide acceptance in
industry, and a particularly popular form of fork lift truck
utilizes the so-called side shifter.
Side shifters typically take the form of an upper
longitudinal plate connected to a lower longitudinal plate
wherein the upper plate utilizes a hook arranged to slidably
engage bearing shoes detachably secured within notches
in a lip portion of an upper carriage bar. The lower longi-
tudinal plate includes transversely movable, rearwardly-
facing sliding or rolling bearings which, under load, exert
an extremely high compressive force against the face of the
carriage. A hydraulic cylinder assembly interposed between
the carriage and side shifter transversely displaces the
side shifter frame with respect to the lift truck carriage
upon actuation of the cylinder assembly. The forwardly-
protruding forks or other carrying means are suspended by
upper fork hooks arranged over the upper plate in order to
hold a load.
One problem with existing forklift truck side shifter
units resides in the fact that bearing wear is heavy and
friction is relatively high. This problem is most notable
in the area of the lower bearings because of the extremely
high compressive contact stresses, accentuated by impact
loading, at these points. This situation results in high
maintenance costs, as well as in high energy usage in
operating a side shifter.
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According to the pres~nt invention there is provided a side shifter
adapted for mounting upon the front of a vertically movable lift truck carriage,
of the ~ype having a transverse mounting member adjacent the top of the car-
riage and a transverse forwardly-facing surface below said transverse mount-
ing member, for mounting a load-handling attachment on the carriage with the
side shifter interposed structurally between the carriage and attachment so
that the atta~hment is transversely movable with respect to the carriage,
said side shifter comprising: (a) forwardly-facing front mounting means for
mounting the load-handling attachment thereon; (b) first rearwardly-facing
mounting means connected to said front mounting means for movably engaging
the transverse mounting member of said carriage so as to vertically support
said front mounting means and permit said front mounting means to move trans-
versely with respect to said carriage; (c) second rearwardly-facing mounting
means connected to said front mounting means, at a location below said first
rearwardly-facing mounting means, for movably engaging the forwardly-facing
surface of said carriage, said second rearwardly-facing mounting means com-
prising a substantially disc-shaped bearing having means defining a rear-
wardly-facing, generally spherical convex bearing surface on one side thereof
for rollingly contacting the forwardly-facing surface of said carriage and
having means defining a forwardly-facing surface on the side thereof opposite
said convex bearing surface; and (d) bearing mounting means on said front
mounting means, for rotatably mounting said disc-shaped bearing upon said
front mounting means, comprising rearwardly-facing surface means for rotat-
ably engaging said forwardly-facing surface of said disc-shaped bearing.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate an exemplary
embodiment of the present invention:
Figure 1 is a partial frontal view showing approximately one-half
of a side shifter apparatus
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mounted on upper and lower carriage bars of a forklift truck,
the forklift truck not being shown;
FIG. 2 is a view taken along lines 2-2 of FIG. l;
FIG. 3 is an enlarged view of the sliding bearing shoe
contacting hook shown in FIG. 2;
FIG. 4 is a partial frontal view of a side shifter
unit illustrating the demountable side shifter actuator hanger
bracket of the present invention;
FIG. 5 is a view taken along lines 5-5 of FIG. 4; and
FIG. 6 is a view similar to that illustrated in FIG. 3
and shows another hook embodiment.
DETAILED DESCRIPTION OF THE INVENTION
Turning now to the drawings, and initially referring
more particularly to FIGS. 1, 2 and 3, indicated generally at 10
is a side shifter apparatus in accordance with the present
invention. While a forklift truck is not illustrated, it is to
be remembered that upper and lower carriage bars 12 and 14,
respectively, are secured to a vertical raising and lowering
device on a forklift truck. Upper and lower carriage bars 12
and 14 are connected together by appropriate joints (not shown).
Upper carriage bar 12 is formed with a lip 12a which has an
upper surface 12_, an inclined rear face 12c and a rear ledge
12d. Rear face 12c is constructed so that forks of a forklift
truck may be releasably attached thereto. Upper carriage bar 12
is also provided with a plurality of notches 13 formed in lip
section 12a arranged to receive sliding bearing shoes, to be
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hereinafter particularly described.
Side shifter apparatus 10 is constructed with an upper
transversely extending plate 16 which is joined by appropriate
cross pieces 18 (one of the cross pieces is not shown, in that
FIG. 1 illustrates only approximately one-half of a side shifter
frame) to a lower transversely extending plate 20. Upper plate
16 is welded or otherwise attached to a connecting plate 22
which is secured to a generally inverted U-shaped hook 24.
While not illustrated, it is to be understood that another
connecting plate 22 would be arranged on the right of side
shifter apparatus 10 similar to illustrated plate 22. Hook 24
is arranged to slidably engage bearing shoes 26. Sliding bearing
shoes 26 provide bearing engagement for sliding contact with
generally ~-shaped hook 24. Sliding bearing shoes 26 may conven-
iently be constructed with a generally Z-shaped cross section
and are removably mounted within notches 13.
As can be best seen from a consideration of FIG. 3,
sliding bearing shoes 26 have a first face 26a arranged for
contact with rear face L2c. Shoes 26 are provided with lugs 26b
which engage notches 13. Surface 26a is formed with generally
the same angle with respect to the vertical as in face 12c.
Such an angle, designated at A, may be approximately 20.
However, a second shoe face 26c is formed with a greater angle
with respect to the horizontal than is face 26a. For instance,
angle B may be arranged at approximately 15 with respect to the
vertical. As a consequence, face 24a of hook 24 remains in
contact with shoe face 26c without tending to climb or ride
upwardly when side shifter 10 is displaced laterally. Further-
more, it is to be noted that hook 24 has a bottom face 24b which
slidably contacts leg segment 26d of sliding bearing shoe 26.
The sliding bearing shoes may be made of nylon filled with
molydisulfide.
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Connected to lower shifter plate 20 is a housing 28
containing in a pocket formed therein a rotatable case hardened
steel disc 30. Disc 30 has a convex curvilinear surface 30a for
contacting lower bar carriage surface 14a and also has a concave
inner surface 30b. Additionally, housing 28 is disposed against
lower carriage bar surface 14a. Disc 30 is set at an angle,
i.e., rotation axis C is set at an angle to face 14a. Thus, it
can be seen that when shifter 10 is laterally displaced, disc 30
rotates within sprocket 28 and rollingly contacts lower carriage
bar 14 in a region 14_ on bar surface 14a. Such contact is
essentially point contact.
A housing seating cup 32 is welded or otherwise at-
tached to a rear face of plate 20 and includes angled portions
32a, 32_. Housing 28 has abutments 28a, 28b which allow inser-
tion of the housing into cup 32 as shown. Thus, replacement of a
roller disc 30 may be readily effected by removal of housing 28 -
and its contained disc, and inserting a new housing and disc into
cup 32. Housing 28 may not inadvertently be placed upside down
in cup 32 because of the aforementioned abutments 28a, 28b. A
further hook 34 is attached to a lower segment of cup 32 and is
arranged to fit about carriage bar lip 14c to prevent substantial
horizontal displacement.
A preferred embodiment of the present invention
incorporates a plurality of replaceable wear shoes 26 and two
housings 28 and discs 30. Also, depending from upper carriage
bar 12 is a mounting bracket 36 which connects a hydraulic
cylinder 38 to a rod 40 which is in turn connected to plate 18.
Hydraulic cylinder 38 is connected to mounting bracket 36 by
means of a pivot connection 37. As hydraulic fluid under pres-
sure is admitted through fitting 38a from a source (not shown)
rod 40 is displaced to the left thereby laterally displacing
side shifter unit 10 to the left. Correspondingly, when fluid
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under pressure is introduced through fitting 38b, rod 40 is
displaced to the right thereby laterally displacing side shifter
10 to the right.
An additional feature of side shifter 10 of the present
invention is also shown in FIGS. 4 and 5 and includes a readily
demountable side shifter actuator hanger bracket 42. Hanger
bracket 42 is provided with a leg 44 including a hook 46 having
a catch or lug 46a arranged to be disposed within a cut-away
central portion or notch 13. A top surface 44a of leg 44 is
constructed to lie beneath the top surface of sliding bearing
shoes 26. Thus, it can be appreciated that no contact between a
lower surface of hook 24 will occur against top surface 44_.
Hanger bracket 42 is securely clamped to the bottom of upper
carriage bar 12 by means of screw clamps 46. Connected to
hanger bracket 42 is a mounting bracket 48 which is connected to
cylinder 38. Cylinder 38 utilizes a rod 40 connected to joint
18 as previously described.
Removal of hanger bracket 42 may be accomplished as
follows. Pin 50 is removed from bracket 52 to permit lateral
displacement of side shifter 10 to the left for removal of same
from carriage bars 12 and 14. Then, clamping bolts 46 may be
loosened from contacting the lower face of upper carriage bar
12. Hanger bracket 42 may then be slightly pivoted and pulled
upwardly out of notch contacting position for ready removal
therefrom. Thus, it can be appreciated that the novel configura-
tion of hanger bracket 42 and central leg 44 provide for ready
mounting and demounting of a side shifter actuator 38, 40.
With reference now directed particularly to FIG. 6,
there is illustrated a further embodiment of a hook connected to
a side shifter. This hook is one that may be used in the setting
of a side shifter like that shown in Figs. 1-3, inclusive.
Specifically, attached to upper bar 16 is a generally U-shaped
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hook 25 having a surface 25a contacting a top leg 26e of sliding
bearing shoe 26. Hook 25 includes an integrally formed leg 25b
secured to upper plate 16. Hook 25 and leg 25_ extend substan-
tially continuously the length of the carriage.
In the embodiment shown in Figs. 1, 2 and 3, hook 24
is continuous, and provides overhead protection for the tops of
the wear shoes. This minimizes dust accumulation. A modifica-
tion which could be made is to use one elongated connecting
plate 22 with this hook, rather than two laterally spaced plates.
Such a modification would further minimize dust accumulation.
Further, it will be noted that discs 30 are substantially sealed
against exposure to the environment.
In the em~odiment shown in Figs. 4 and 5, the hook
still extends over a substantial portion of the wear shoes at
all times, thus to provide protection.
While a preferred embodiment of the invention has been
described herein, it should be apparent to those skilled in the
art that variations and modifications are possible without
departing from the spirit and scope of the present invention
defined in the appended claims.
