U.S. patent number 3,851,779 [Application Number 05/389,138] was granted by the patent office on 1974-12-03 for lift truck fork retaining pins.
This patent grant is currently assigned to Towmotor Corp.. Invention is credited to John T. Crawford.
United States Patent |
3,851,779 |
Crawford |
December 3, 1974 |
LIFT TRUCK FORK RETAINING PINS
Abstract
A lift truck fork carriage construction is provided with fork
positioning retainers that are securely mounted on the carriage
structure whereby said retainers cannot be jolted off or misplaced
from the fork carriage during lift truck operations.
Inventors: |
Crawford; John T. (Lyndhurst,
OH) |
Assignee: |
Towmotor Corp. (Cleveland,
OH)
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Family
ID: |
26919937 |
Appl.
No.: |
05/389,138 |
Filed: |
August 17, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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225811 |
Feb 14, 1972 |
3780896 |
Dec 25, 1973 |
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Current U.S.
Class: |
414/667;
414/785 |
Current CPC
Class: |
B66F
9/12 (20130101) |
Current International
Class: |
B66F
9/12 (20060101); B66f 009/06 () |
Field of
Search: |
;214/730,731,750 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Spar; Robert J.
Assistant Examiner: Oresky; Lawrence J.
Attorney, Agent or Firm: Phillips, Moore, Weissenberger,
Lempio & Strabala
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a division of application Ser. No. 225,811,
filed Feb. 14, 1972, now U.S. Pat. No. 3,780,896 which issued on
Dec. 25, 1973.
Claims
What is claimed is:
1. In a lift truck of the type having an extensible mast structure,
a carriage mounted for travel along said mast, and load forks
mounted on said carriage with means for allowing side-to-side
adjustment of said forks, the improvement comprising;
fork retainer means coacting with said carriage and said forks to
restrain said forks in a predetermined position on said
carriage,
means for permitting at least partial removal of said retainer
means from said carriage for adjusting said forks to new
positions,
and positive restraining means coacting with said retainers to
prevent loss of said retainers from said carriage, said positive
restraining means comprising in combination, an upper portion of
the carriage extending upwardly beyond the mounting position of
said forks and said retainers, crossbar members defining a
transverse recess and forming part of said carriage upper portion
and positioned at a distance above said retainers such that the
retainers may be moved upwardly in relation to said carriage and
yet are retrained from being removed from said carriage by having
the upper portion of said retainers being closely confined by said
recess.
2. The combination of claim 1 wherein said recess terminates at a
distance from the side of said carriage whereby said retainers can
be removed from said carriage by following a tortuous path through
the upper portion of said carriage.
Description
BACKGROUND OF THE INVENTION
To increase the versatility of fork lift vehicles, fork carriages
have been developed wherein the distance between the forks may be
arbitrarily varied so that loads of different widths may be lifted
and handled. One current method of spacing the forks on the
carriage is to provide a cross shaft on the carriage structure with
the upper portion of the forks being slidably mounted thereon for
transverse movement with relation to the fore and aft axis of the
vehicle. In such a construction the forks are slid from side to
side on the carriage cross shaft until the desired spacing thereof
is obtained.
Retainer devices are thereupon engaged with the forks and/or the
carriage cross shaft to fixedly retain the forks in the desired
spacing. Such retainer devices or spacers are generally U-bolt
shaped and extend through holes in the carriage structure to
straddle the top of the forks and rest against the top of the cross
shaft to thus restrict the forks from any lateral movement on the
cross shaft.
Such retainer devices are, however, subject to loss since they may
be jolted loose from the vehicle carriage or otherwise lost. Losing
such retainers is a great inconvenience and may also account for
lost work time while new retainers are procured and replaced on the
carriage stucture.
BRIEF SUMMARY OF THE INVENTION
The present invention provides permanently installed fork retainers
which allow for the lateral positioning of the forks to a desired
location on the cross shaft and may then be positioned to restrict
the lateral movement of the forks when the retainer is in place.
However the fork retainers of the present invention cannot be
accidentally jolted off the truck or misplaced when the fork
positions are being changed, or when the carriage is handling a
load. The retainers are a semi-permanent part of the carriage
structure, and thus cannot be lost from it thereby eliminating the
prior problem of replacing lost retainers.
The fork retainers of the present invention are generally of a
configuration similar to prior art retainers however their
structure is modified and the fork carriage structure is altered
such that the retainers may be moved out of the way to effect
repositioning of the forks, but at the same time cannot be removed
from the carriage structure itself. Mechanisms are attached to the
carriage structure to co-act with the fork retainers in such a way
that the retainers may be manipulated as noted above.
Accordingly it is a primary object of this invention to provide
lift truck carriage fork retainer means that cannot be lost from
the carriage structure.
It is another object of the invention to provide fork retainer
devices that allow quick and easy lateral adjustment of the forks
but which are at the same time impossible to lose or misplace from
the carriage structure.
Additional advantages and features of the present invention will be
made apparent from a review of the following specification and the
accompanying drawing wherein:
FIG. 1 is a perspective view of the preferred embodiment of the
lift truck fork carriage structure, the forks and the novel fork
retainers of the invention.
FIG. 2 is a front sectional view of the upper left-hand portion of
the carriage with the retainer in its fork locking position.
FIG. 3 is a cross sectional view of the upper portion of the
carriage with the fork retainer in position as in the case of FIG.
2.
FIG. 4 is a perspective view of an alternate embodiment of the
invention.
FIGS. 5, 6, 7 and 8 are views of the alternate embodiment showing
the sequence of assembly of the fork retainer into the subject
carriage.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now in detail to the drawings, and with a special
reference to FIGS. 1, 2 and 3, the lift truck carriage 10 of the
present invention is basically similar to the present shaft type
carriages with the exceptions as hereinafter noted and described.
said carriage 10 comprises a conventional frame structure 15 upon
which is mounted load forks 12 and 14 by means of a cross shaft 18
which is secured to the frame transversely and slightly below the
carriage top crossbar 16.
A series of vertical holes 17 are bored through top crossbar 16. A
number of fork retainer assemblies 24 equal to the number of forks
retained on the carriage are mounted into the top portion of
carriage frame 15. These fork retainer assemblies 24 are of a
generally U-shape whose legs are of a width sufficient to pass
through any two holes 17 and straddle the upper portions of forks
12 and 14.
Each fork retainer assembly 24 consists of the substantially
U-shaped member 28 with a spring clip 26 secured to the upper cross
portion of the assembly by a fastening means 30 in the manner as
shown in FIGS. 1, 2 and 3. The U-shaped member 28 has flats 32
formed into the opposite sides of each leg whereby the cross
sections of such leg portions are narrower than the adjacent
circular cross sections thereof. These reduced cross sections of
U-shaped member 28 permit the legs thereof to pass freely through
holes 17 in crossbar 16, but however restrict the complete removal
of members 28 from vertical withdrawal due to the interference
posed by retaining strips 22 which are securely fastened to the top
surface of crossbar 16. The slot formed by the opposing side
surfaces of strips 22 is sufficiently wide to permit the reduced
leg portions of members 28 to pass therethrough, but of
insufficient width to permit the full circular cross section of
such legs to pass in either direction.
The two retaining strips 22 are secured to the crossbar 16 in such
a manner that fork retainer assemblies 24 can be raised vertically
to a position where the formed flats 32 bear against the undersides
thereof and the full round shape of the U-bolt members 28 restrict
further vertical movement. In this position the retainer assembly
24 can be moved in a transverse direction to any point above a
selected pair of holes 17 in bar 16.
With the retainer assemblies 24 held in their upper and unlatched
positions the forks 12, 14 may be shifted from side to side to any
desired position on cross shaft 18. When in the desired position
the retainers 24 are pushed down through respective selected holes
in cross member 16 to straddle the upper portion of the forks and
bear against cross shaft 18 whereby further side-to-side movement
of the fork is prevented.
With reference to FIG. 3, it will be noted that with retainer
assembly 24 in the fork retaining position the spring clip 26
latches into adjacent restraining strips 22 whereby the retainer is
securely held in position to prevent sidewise movement of forks 12,
14 and to further prevent the accidental jostling of the retainers
out of the holes 17 in cross member 16.
As shown in FIGS. 1 and 2, pins 20 are provided at either end of
crossbar 16. These pins 20 are retained by a press fit in holes
passing vertically through the ends of crossbar 16 and cross shaft
18. The top portion of pins 20 project upwardly above crossbar 16
and above the upper surface of retainer strips 22. Thus it will be
seen that when retainers 24 are pulled out of holes 17, they may be
moved transversely in the slot formed between retainer strip 22
from side to side on carriage 15; however they are prevented from
being removed therefrom by the upwardly projecting portions of pins
20.
In the event it is necessary to replace any one or all of the
retainers 24, one or both of the pins 20 is removed from the
carriage whereby the retainer may be simply slipped off of carriage
15 through the openings at the ends of retainer strips 22.
It will be appreciated that the construction shown in the drawings
and described hereinabove provides means for securely preventing
side-to-side movement of forks 12, 14, and at the same time guards
against the loss or accidental removal of retainers 24 from the
carriage structure 10. At the same time the forks 12, 14 may be
easily repositioned from side to side on the carriage structure 10
and thereafter be securely held in position by the retainers
24.
A second embodiment of the fork retainer assembly is illustrated in
FIG. 4 of the drawing. In this instance the carriage frame 101 is
generally similar to the carriage frame of previous mention, with
the addition, however, of an upwardly extending portion 102
thereof. Such upward extension consists of a topmost crossbar 110
supported by the usual side members which also in turn support an
intermediate crossbar 116 having a plurality of holes 117 drilled
vertically therethrough at appropriately spaced intervals.
Immediately below crossbar 116 is the fork retaining shaft 118 upon
which the upper portions of forks 112 and 114 are slidably secured
and mounted.
There is provided, a short distance above crossbar 116, a pair of
crossbars 128 which are secured to the upright carriage side
members and in spaced relation one to the other.
Fork retainers 124 in a number equal to the forks retained on
carriage 101 are provided. Each retainer is of a generally U-shaped
construction with the leg portions thereof spaced apart by the
exact distance between any two adjacent sets of holes 117. The legs
of retainers 124 are further sufficiently spaced apart to straddle
the upper mounting portion of forks 112 and 114. Thus when a
retainer is dropped through the holes 117, the ends of the legs
thereof will bear up against cross-shaft 118 in straddling relation
to the mounting portion of the forks. In such position the
retainers will prevent the side-to-side movement of the forks in
exactly the same manner as previously described above.
If it is desired to move the forks from side to side, pins 124 are
manually withdrawn from contact with cross-shaft 118 upwardly until
the upper cross portion passes up into the confining space or
recess between crossbars 128. Further upward movement of the
retainer 124 is prevented by a keeper plate 126 secured across the
upper surfaces of crossbars 128.
When the retainers are withdrawn up into the recess between
crossbars 128, the bottom portions of the legs thereof are free of
holes 117 and the retainer may be moved from side to side into any
desired position on the carriage frame. Having moved the forks, the
retainers 124 may then be dropped down through the desired set of
holes 117 to securely retain the forks in the desired position.
When the retainers 124 are either manually or accidentally
withdrawn from crossbar 116, the cross portion between the legs
thereof is closely confined between the crossbars 128 and keeper
bar 126, whereby it is impossible for the retainer to be lost or
removed from the carriage structure.
Keeper plate 126 is somewhat shorter than the distance between the
upright side members of frame 101, and is secured atop crossbars
128 such that a free space is left between said bars at each end
thereof. This open portion at each end of crossbars 128 is of a
dimension such that retainers 124 may be inserted or removed from
the carriage structure by following the sequence of operation shown
in FIGS. 5 - 8.
The full sequence of retainer assembly into the carriage 101 begins
with FIG. 5, showing said retainer 124 poised on end above the bars
128 and with its legs against the end plate of carriage 101. FIG. 6
shows the retainer passing downwardly between the two bars 128 into
the space between the bars 128 and 116. FIG. 7 indicates that the
retainer has been rotated 90.degree. from that position shown in
FIG. 5, and having been moved into the space immediately above
crossbar 116. As noted in FIG. 8, the retainer 124 has been dropped
down into the final assembled position in crossbar 116 and in
straddling relation to the mounting portion of fork 114. The
retainers 124 are removed from the carriage frame 101, if desired,
by following a sequence exactly in reverse to that shown in FIGS.
5, 6, 7 and 8.
Thus it will be seen that although the retainers 124 cannot be
accidentally removed from the carriage frame 101, they can if
desired be removed therefrom by following the sequence of
operations as shown. Thus broken or damaged retainers can be
replaced on the frame, but yet cannot be accidentally lost
therefrom.
There has been described above the preferred embodiments of the
present invention, but it will be apparent to anyone skilled in the
art that various other forms thereof can be provided without
departing from the spirit and scope of the invention. All such
variations are contemplated herein, so long as they fall within the
scope of the following claims.
* * * * *