Single lever control device for multiple functions

A compact single lever control device (26) is provided for a lift truck (11) which permits an operator to operate a carriage raising and lowering control valve spool (77) by lateral movement of a manual control lever (46) and to cause the lift truck to travel in forward and reverse directions by forward and reverse movement of the control lever (46).

BACKGROUND OF THE INVENTION 
1. Technical Field 
This invention relates to a single lever control device for effecting 
multiple functions such as forward/reverse speed and carriage lift/lower 
functions in a lift truck. 
2. Prior Art 
The use of single lever control devices for multiple functions is well 
known. For instance, U.S. Pat. No. 3,741,031 shows a single lever control 
device wherein a control lever extends through a radial opening in and is 
pivotally connected to an apertured busing 36. The control lever includes 
an arm extending through an axial opening in the bushing which connects to 
a first control member. The bushing is mounted on two widely spaced 
bearings. Rotation of the bushing about its axis causes a first control to 
be activated and swinging movement of the control lever relative to the 
bushing causes a second control to be actuated. U.S. Pat. No. 4,019,401 
shows a manual control lever for a plurality of operating functions which 
is supported by a ball and socket joint with a stabilizer link supporting 
and stabilizing movement of the control lever. U.S. Pat. No. 4,027,547 
shows a single lever control for multiple functions wherein the control 
lever is supported for universal movement. U.S. Pat. No. 3,811,336 shows a 
lift truck controller operable to control raising and lowering of the pay 
load, tilting of the mast, forward and reverse travel and speed. 
OBJECTS AND DESCRIPTION OF THE INVENTION 
It is an object of the present invention to provide a multiple function 
control which is very compact so as to fit in the limited space available 
in a standup rider lift truck. 
It is a further object of the present invention to provide an improved 
single lever control for a lift truck wherein the lift truck operator can 
control lifting and lowering of the carriage, travel speed and direction 
with a single manually operated lever. 
It is a further object of the present invention to provide a single lever 
control for a lift truck which is reliable in operation, easy to service 
and relatively inexpensive in cost. 
The single lever control device of this invention includes an upstanding 
support wall having laterally opposite sides, wall means defining a 
bearing receiving opening and bearing means mounted in the bearing 
receiving opening. The bearing means includes a bearing member within the 
opening rotatable only about a bearing axis transverse to the wall and 
having wall means defining a central opening through which the bearing 
axis passes. A control lever is provided which has an upstanding hand grip 
portion and a horizontal leg extending into the central opening where 
pivot means pivotally connect the leg to the bearing member for relative 
pivotal movement only about a pivot axis transverse to the bearing axis. A 
first control is pivotally connected to the bearing member at a first 
point spaced from the bearing axis and a second control is pivotally 
connected to the leg of the control lever at a second point spaced from 
the pivot axis. Pivoting of the lever about the bearing axis causes 
actuation of the first control and pivoting of the lever about the pivot 
axis causes actuation of the second control.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 and 2, a standup rider lift truck 11 includes a main 
frame 12 on which a lift mast 13 is secured. The pay load is carried by a 
pair of forks 10 mounted on a carriage 20 which is raised and lowered on 
the mast 13 by a single acting hydraulic jack, not shown. A pair of 
straddle legs 14, 15 of the frame 12 are supported at their front ends by 
small wheels 16, 17 and the rear of the frame 12 is supported by a pair of 
steerable wheels 18, 19. At least one of the rear wheels is driven by an 
electric motor, not shown, to which power is supplied by an electric 
battery 21. A steering lever 23 is provided adjacent the left hand side of 
the operator station 24. 
The single lever control device 26 of the present invention is located at 
the right hand side of the operator's compartment 24. Referring also to 
FIGS. 3 through 7, the support 27 for the single lever control 26 is 
fastened to the main frame 12 of the truck by screws 28. The support 27 
includes a flat bottom plate 31 to which a pair of upstanding flanges or 
walls 32, 33 are welded. An upstanding wall or bearing block 36 is 
secured, as by welding, to the upper ends of the longitudinally spaced and 
parallel vertical walls 32, 33 with the lower end 37 of the bearing block 
being spaced vertically above the bottom plate 31. The upstanding wall or 
bearing block 36 includes a bore 38 into which a bushing 40 is press fit. 
The bushing constitutes wall means presenting a radially inner facing 
cylindrical bearing surface or bearing receiving opening 39 extending to 
laterally opposite sides of the wall 36. Bearing means are provided within 
the bearing receiving opening 39 and include a bearing or control member 
42 with a radially outward facing annular surface in radial thrust 
transmitting relation with the bearing surface 39 on the bearing block 36. 
The bearing member 42 is secured against axial movement relative to the 
bushing 40 by a retainer in the form of a snap ring 45 disposed in an 
annular circumferential groove in the bearing member and in axially 
confronting relation to one axial end of the bushing 40. The bearing 
member 42 rotates relative to the wall 36 only about a bearing axis 43 and 
includes a main part disposed within the opening 38 in the wall and 
presenting wall means defining an axial opening 44. A manually operable 
lever 46 includes an upstanding hand grip portion 47 and a horizontal leg 
48 extending into the opening 44 where an intermediate portion of the leg 
48 is pivotally connected to the bearing member 42 on a pivot axis 51 
transverse to bearing axis 43 by pivot means 52 disposed within the 
opening 44. The pivot means 52, as shown in FIG. 7, includes a cylindrical 
pivot member or pin in the form of a sleeve 53 on a pivot axis 51 mounted 
in a bore 54 in the lever 46 by a pair of axially aligned stepped diameter 
bushings 55, 55'. The sleeve 53 fits in a bore 56' in the leg 48 of the 
lever 46 and is secured against rotation by a set screw 57'. The bore 54 
is actually two bores formed on the pivot axis 51 and extending radially 
in relation to the bearing axis 43 from the central opening 44 in the 
control member 42 to the radially outward facing cylindrical bearing 
surface of the control member 42. The stepped diameter bushings 55, 55' 
have inner bores in radial bearing engagement with portions of the pivot 
pin 53 extending outwardly from the intermediate portion of the leg 48 and 
have radially outward facing cylindrical bearing surfaces in bearing 
engagement with the aligned bore segments constituting bore 54. The 
radially outward extending flanges of the stepped diameter bushings 55, 
55' are in axial bearing engagement with opposite sides of the central 
opening 44 and the central portion of the leg 48 of the control lever 46. 
The pivot axis 51 is disposed between the opposite sides of the wall 36, 
intersects bearing axis 43 and lies adjacent the central vertical plane 56 
of the annular bearing member 42. The leg 48 of the lever 46 extends 
through the opening 44 a short distance terminating in a free end in the 
form of a spherical bearing component 57 which is pivotally connected to a 
control link 58 of a lift/lower control. 
The lift/lower control includes a rock shaft 61 having an arm 62 secured 
thereto by a pin 65. The outer end of the arm 62 is pivotally connected to 
the control link 58 at a point 63 vertically below the point 64 of 
connection between the link 58 and the free end 57 of the leg 48 of the 
control lever 46. The rock shaft 61 is journaled in the wall 32 by bushing 
66, passes through an opening 67 in the wall 33 and is supported by a 
bushing 69 in a bracket 68 welded to the plate 31. The rock shaft 61 is 
disposed directly below the bearing block 36 with the arm 62 connected 
thereto in the opening 71 defined by the lower end 37 of the block 36, the 
upper side of the plate 31 and the confronting sides of the bearing block 
support walls 32, 33. This arrangement provides a laterally compact 
control device of the limited space available at the right side of the 
operator's compartment 24. 
A hydraulic control valve 76 of the lift/lower control is mounted on the 
lift truck at the front of the operator's compartment 24 and includes a 
valve spool 77 having one end pivotally connected to one end of a control 
link 78 by a pin 79. The other end of the link 78 is pivotally connected 
by a ball pivot joint 81 to an arm 82 secured to the rock shaft 61 by a 
pin 83. The hydraulic control system for raising and lowering the carriage 
20, includes a hydraulic pump, not shown, driven by an electric motor, not 
shown, which is energized to drive the pump only when the valve spool 77 
is moved to the right as viewed in FIG. 3. This is achieved through 
actuating a switch 86 in the pump control circuit by a cam element 87 on 
the link 78 causing a roller carrying arm 88 of the switch 86 to move to 
the left as viewed in FIGS. 4 and 5 when the valve spool 77 and link 78 
are moved to the right, as viewed in FIG. 3, by clockwise rotation of the 
control lever 46. 
Forward and reverse travel and truck speed are achieved by an electric 
drive motor control including a pivotable electric control 91 having a 
pivot arm 92, the free end of which is pivotally connected to one end of a 
control element in the form of a link 93. The other end of the control 
link 93 is pivotally connected to the free end of an upstanding arm 94 
integral with and extending from one lateral side of the bearing member 42 
by a spherical bearing 96 which is spaced above the axis 43 of the bearing 
member 42. 
OPERATION 
When the operator wishes to raise the load carriage 20, he moves the 
control lever 46 to the right, as viewed in FIGS. 2, 3 and 6, thereby 
causing the rock shaft 61 to rotate clockwise which in turn causes the 
link 78 and the valve spool 77 to be moved to the right from its detented 
neutral position to its raise position. Such shifting movement of the link 
78 causes the switch 86 to be actuated which in turn causes a fluid pump 
to deliver pressure fluid to the lift jack, not shown, via the valve spool 
77 which is in its raise position. Lowering of the carriage 20 is achieved 
by pivoting the lever 46 counterclockwise, as viewed in FIGS. 2, 3 and 6, 
to cause the valve spool 77 to shift to the left from its detented neutral 
position, in which illustrated, to its lower position which permits 
exhaust of fluid from the single acting lift jack. Since pressurized fluid 
is not required for a carriage lowering operation, the switch is not 
actuated and the hydraulic pump is not operated. 
When the lift truck operator desires to move the truck forward the control 
handle is moved in a forward or clockwise direction as viewed in FIGS. 1 
and 5. Such movement causes the electric drive motor control lever 92 to 
move counterclockwise as viewed in FIG. 4. Initial forward movement of the 
lever 92 from its neutral position, to which it is biased, establishes the 
forward direction of travel and further forward movement progressively 
increases the speed of travel in the forward direction. Rearward movement 
of the manual control lever 46 from its illustrated neutral position 
causes progressively increased speed of travel in a reverse direction. 
The mounting of the manual control lever 46 on a single, relatively narrow 
bearing member 42 for relative rotation only about bearing axis 51 and the 
pivoting of the bearing member 42 to the support wall 36 for relative 
rotation only about axis 43 with axes 51 and 43 intersecting adjacent the 
central vertical plane 56 of the wall 36 provides a very compact single 
lever control device for operating two lift truck controls.