US3187841A

US3187841A - Fork lift vehicle

Info

Publication number: US3187841A
Application number: US203772A
Authority: US
Inventors: Renshaw Robin
Original assignee: MODERN HYDRAULICS Inc
Current assignee: MODERN HYDRAULICS Inc
Priority date: 1962-06-20
Filing date: 1962-06-20
Publication date: 1965-06-08
Anticipated expiration: 1982-06-08

Description

R. REQNSHAW 3,187,841 FORK LIFT VEHICLE 4 Sheets-Sheet 1 June 8, 1965 Filed June 20. 1962 June 8, 1965 R. RENSHAW FORK LIFT VEHICLE 4 Sheets-Sheet 2 Filed June 20. 1962 INVENTOR. E0567? Hens/242w,

III 1 W 4 Sheets-Sheet 3 Filed June 20, 1962 INVENTOR.

June 8, 1965 R. RENSHAW FORK LIFT VEHICLE 4 Sheets-Sheet 4 Filed June 20, 1962 INVENTOR. I 1 201507, [Zens/2am,

/11 BY Z W M United States Patent 3,187,841 FQRK LIFT VEHICLE Robin Renshaw, West Chicago, Ill., assignor to Modern gydranlics, Inc, West Chicago, Ill., a corporation of H1015 Filed June 20, 1962, Ser. No. 203,772

11 Claims. (Cl. 187-9) The present invention is directed to a fork lift vehicle and, more particularly, to a lightweight fork lift vehicle which is propelled or motivated by foot-operated pedals.

Most fork lift trucks now inuse are relatively large, being rated for loads of two thousand pounds and up, and are either electrical or gasoline powered units. The size, weight, and high cost of such conventional fork lift trucks does not warrant their use above ground or first floor levels or where lighter loads are to be transferred between points which are not spaced considerable distances apart. Such conventional fork lifttrucks are also not adapted for use where noise is objectionable and cleanliness is important, as in hospitals, laboratories, food stuff and drug outlets, etc., or where inflammable materials are stored because of the danger of the machine sparking and causing explosions, as in chemical manufacturing plants, inflammable material industries, etc.

It is, therefore, an important object of the present invention to provide a new and novel fork lift vehicle which is simple, silent, clean, and efficient in operation, which is relatively inexpensive, compact and lightweight, weighing only about two hundred and fifty pounds while being rated for lifting loads up to five hundred pounds or one thousand pounds, and which is characterized by the absence of gasoline fumes or electrical operating parts which could cause sparking and thus be dangerous where inflammable materials are present.

Another important object of the present invention is to provide a new andnovel fork lift vehicle having the foregoing characteristics and which is particularly well adapted for use in food stores and food wholesale outlets, drng houses, laboratories, chemical manufacturing plants, industries marketing inflammable materials, hospitals, etc.

Another important object of the present invention is to provide a new and novel fork lift vehicle having the foregoing features which includes a lightweight frame structure mounted on wheels and having a seat and a steering mechanism, a lifting fork movable in a vertical direction on the forward end of the frame structure, and footoperated pedals operably connectable by chain and sprocket means to certain of the Wheels for propelling or driving the vehicle.

Another important object of the present invention is to provide a new and novel pedal-propelled fork lift vehicle of the character described wherein the lifting fork is pivotally mounted on a vertically movable fork carriage for vertical movement therewith and for pivotal movement relative thereto between a first operable position in which the lifting fork projects forwardly of the front end of the vehicle and a second position in which the lifting fork extends rearwardly of thefront end of the vehicle, in which second position the over-all length of the vehicle is substantially shortened to increase the maneuverability thereof and to permit the vehicle to fit in a standard size elevator, the relative lightness of the vehicle permitting use of same above a first or ground level.

ice

Another important object of the invention is to provide a new and novel pedal-propelled fork lift vehicle of the character described wherein the lifting fork may'be raised and lowered either by a chain and sprocket mechanical connection from the foot-operated pedals or by a hydraulic unit actuated by pump means on the vehicle, which pump means may be either a hand-operable pump, an electric motor-driven pump, or a rotatably drivable pump which is mechanically connectable to the foot-operated pedals by chain and sprocket means.

i A further object of the present invention is to provide in a pedal-propelled fork lift vehicle of the character described, wherein the lifting fork is either vertically movable mechanically through chain and sprocket means connectable to the foot-operated pedals or hydraulically by a pump which is drivingly connectable through chain and sprocket means to the foot-operated pedals, a manually operable shifting mechanism whereby the foot-operated pedals may be selectively connected to the drive wheels fork being shown in its normal forwardly projecting position in full line and in its rearwardly pivoted position in broken line and ,with the maximum and minimum height positions of the lifting fork being shown in broken line;

FIG. 2 is a top plan view of the fork lift vehicle of FIG. 1;

FIG. 3 is a rear end elevational view of the fork lift vehicle of FIGS. 1 and 2;

FIG. 4 is a perspective view of the foot-pedal drive to the front drive wheels;

FIG. 5 is a partially broken side elevational view of the steering mechanism for the single rear wheel of the vehicle with certain parts shown in vertical section;

FIG. 6 is a horizontal sectional view taken generally on the line 66 of FIG. 5;

FIG. 7 is a partially broken enlarged vertical central section taken generally on the line 7-7 of FIG. 2 through the hydraulic cylinder and piston unit provided in three forms. of the invention;

FIG. 8 is a front elevational view of the fork carriage;

FIG. 9 is a side elevational view thereof;

FIG. 10 is a top plan view thereof;

FIG. ll is an enlarged scale horizontal sectional "iew taken generally on the line 11-11 of FIG. 8;

FIG. 12 is an enlarged scale vertical sectional View taken generally on the line 12-12 of FIG. 8;

FIG. 13 is a side elevational view of one form of the invention wherein a manually operable pump is provided for actuating the hydraulic cylinder and piston unit with the basic vehicle structure being shown in broken line;

FIG. 14 is an enlarged scale central vertical section through the manually operable pump of FIG. 13;

FIG. 15 is a partial side elevational view of a second form of the invention in which an electric motor-driven pump is provided for actuating the hydraulic cylinder and 3 4 piston unit with the rear portion of the basic vehicle structure being shown in broken line;

FIG. 16 is a schematic diagram for the electric motordriven pump of FIG.

FIG; 17 is a diagrammatic side elevational view of the pedal-drive for a third form of the invention wherein a pump for actuating the. hydraulic cylinder and piston unit is mechanically driven by the foot-operated pedals;

FIG. 18 is a diagrammatic top plan view of the pedaldrive of FIG. 17; i

FIG. 19 is an enlarged scale vertical sectional view taken generally on the line 19-19 of FIG. 18;

FIG. 20 is a partially broken perspective view of the shifting mechanism provided for the pedal-drive of FIGS. 17 and 18;

FIG. 21 is a diagrammatic side elevational view of the pedal-drive for a fourth form of the invention wherein the lifting fork is raised and lowered by a mechanical con nection to the foot-operated pedals;

' FIG. 22 is a partially broken rear elevational view taken generally on the line 22-22 of FIG. 21; and

FIG. 23 is a fragmentary vertical sectional view showing the lifting fork in its normal forwardly projecting position in full line and in its rearwardly extending position in broken line.

Four embodiments of the pedal-propelled fork lift vehicle of the invention are illustrated in the drawings. As will be evident hereinafter, the primary difference between these four embodiments is in the means provided for moving the lifting fork in a generally vertical direction. In three forms of the invention the lifting fork is raised and lowered by a hydraulic cylinder and piston unit which is operably connected to either a manually operable pump, an electricmotor-driven pump,or a rotatably drivable pump which is mechanically connectable to the foot-operated pedals of the vehicle. In the fourth form ofthe invention, the lifting fork is mechanically raised and lowered by the foot-operated pedals.

In describing the various forms of the invention, structure which is identical in two or more of these forms will be identified by the same reference characters for reasons of clarity and convenience. The basic vehicle structure and mechanisms common to all four forms of the invention will first be described after which each of the four forms will be described in detail.

As best illustrated in FIGS. 1, 2 and 3, the main 'body or frame structure 25 is of a generally elongated narrow hollow channel structure having a generally horizontally disposed top wall 26, a bottom wall 27 which tapers downwardly from the rear end of the vehicle toward the front end thereof, and opposite side walls 28. The frame structure 25 could, for example, be formed of inch .steel plate. A pair of relatively widely spaced apart front drive wheels 30 are mounted on the ends of a drive axle 31 extending through an axle housing 32 which is mounted in the lower front corner of the frame structure 25 in a suitable manner. As best illustrated in FIGS. 1, 3 and 5, a single turnable rear wheel 33 is provided at the rear end of the frame structure 25 for supporting and steering the fork lift vehicle. The rear wheel 33 is mounted in a downwardly opening yoke portion 34 at the lower end of a vertically disposed shaft 35 which is rotatably mounted in the frame structure 25 and has a sleeve bearing 36 and a thrust bearing 37 associated therewith. The front drive wheels 30 and the rear turnable wheel 33 may be provided with either solid or pneumatic rubber tires. A hollow box-like container structure 38 is secured, as by welding, on the frame structure 25 at the rear end thereof for a purpose which will be described hereinafter and an adjustableseat 39 is mounted thereon.

As best illustrated in FIGS. 1 and 4,. foot-operated pedals 40, similar to those associated with bicycles and operable by a person sitting in the seat 39, are secured on the opposite ends of a pedal shaft 41 which is rotatably 4 mounted in the frame structure 25 in a suitable manner. The front wheel drive axle 31 is provided with a commercial differential unit 43 (FIG. 4) having a driven sprocket 44 secured thereon whereby to provide a positive drive for both the front wheels 30. In the form of the invention shown in FIGS. 1-4, a drive sprocket 45 is mounted on the pedal shaft 41 inwardly of the frame structure 25 with a sprocket chain 46 extending about the drive sprocket 45 and the driven sprocket 44 associated with the drive axle 31 whereby to provide a vehicle which is pedal-propelled forwardly or rearwardly. An adjustment idler sprocket 47 (FIG. 4) for the sprocket chain 46 may also be provided.

The steering mechanism for turning the rear wheel 33 to steer the vehicle may best be described with reference to FIGS. 1, 5 and 6. An upstanding steering shaft housing 49 is mounted on the top wall 26 of the frame structure 25 forwardly of the seat 39 and at a slight rearward angle for the convenience of a person sitting in the seat 39. A jointed steering shaft 50 extends through the housing 49 with the upper end thereof extending through a bearing 51 mounted in the upper end of the steering shaft housing 49 and having a steering wheel 52 mounted thereon. A lower vertically disposed portion of the steering shaft 50 is mounted in the frame structure 25 with a sleeve bearing 53 associated therewith. The steering shaft 50 is characterized by upper and lower sections connected by a standard universal joint 54 whereby the upper section may be accommodated in the slightly rearwardly tilted steering shaft housing 49.

A sprocket 56 is secured on the lower end of the steering shaft 59 with a sprocket 57 being secured on the rear wheel shaft 35 rearwardly of the steering shaft sprocket '56 and an adjustable idler sprocket S-Sbeing mounted in the frame structure 25 forwardly of the steering shaft sprocket 56. As best illustrated in FIG. 6, a sprocket chain 59 extends about the rear wheel sprocket 5'7 and the idler sprocket 58 and about one side of the steering shaft sprocket 56 in a manner such that when the steering wheel 52 is turned to the right the vehicle will turn to the right and vice versa.

A generally vertically disposed guide and support structure 61 is secured at its lower end, as by welding, to the front end'of the frame structure 25 with the major portion of the guide and support structure 61 projecting thereabove. As best illustrated in FIGS. 3 and 10, the guide and support structure 61 is characterized by a pair of laterally spaced apart inwardly opening U-shaped steel channel members 62 which are interconnected at their upper and lower ends by

plate members

63 and 64, respectively. A fork carriage 66, best illustrated in FIGS. 8,

9, l0 and 11, is mounted on the guide and support structure 61 for generally vertical movement relative thereto. The fork carriage 66 is characterized by a vertically extending rearwardly opening U-shaped bracket 67 which is disposed between the channel members 62 of the guide and support structure 61 with each rearwardly extending side portion 68 thereof having a pair of vertically spaced cast iron rollers 69 rotatably mounted thereon with each pair of rollers 69 being confined for rolling engagement in one of the U-shaped channel members 62 of the guide and support structure 61. As best illustrated in the detail view of FIG. 11, each roller 69 is rotatably mounted on the outer end of a hardened pin 70 by means of a bushing or roller bearings 71 with the opposite inner end of the pin 74) being retained by a set screw 72 in a hub 73 which is secured, as by welding, on the inner surface of the rearwardly projecting side portion 68 of the U-shaped bracket 67. A steel washer 74 is provided on each pin 70 between the roller69 and the outer surface of the rearwardly projecting side portion 68 of the bracket 67. The bracket 67 of the fork carriage 66 could also be slidably mounted between the U-shaped channel members 62.

The fork carriage 66 is further characterized by a pair of vertically, spaced horizontally disposed rearwardly opening channel members 76 of substantial lateral width which are secured, as by welding, to the front surface of a transversely extending front portion 77 of the U-shaped bracket 67. The opposite ends of the channel members '76 are provided with side plates 78 which project above the uppermost channel member 76 with the upper projecting portions thereof being provided with horizontally aligned bores 79. A rod 80 (FIG. 2) extends through the aligned bores '79 in the side plates 78 and. is secured therein by nuts 81 threadedly mounted on the opposite ends thereof. A lifting fork 82 defined by a pair of rightangular lifting members is mounted on the rod 80 for generally vertical movement with the fork carriage 66. In their normal operable positions, each right-angular lifting member is characterized by a forwardly directed load supporting portion 83, a vertically disposed portion 84 extending upwardly from the rear end thereof and dis posed against the front surfaces of the channel members 76, and by a rearwardly extending collar portion 85 at the upper end of the vertically disposed portion 84, which collar portion 34 is rotatably and slidably mounted on the rod Sti whereby the lifting fork 82 is both vertically movable with the fork carriage 66 and rearwardly pivotable relative thereto about the rod 80. g

In the first three forms of the fork lift vehicle to be described herein, the fork carriage 66 and the lifting fork 82 are vertically movable by hydraulic means. As best illustrated in FIGS. 1 and 7, a generally vertically disposed hydraulic cylinder 86 having its lower end closed by a iounting block plug 87 is mounted on the lower plate member 64 of the guide and support structure 61 between the U-shaped channel members 62 thereof. A piston 88 in the cylinder $6 is secured on the lower end of a piston rod $9 by a retaining ring ht The piston rod 39 projects upwardly out of the cylinder 86 through a bronze bushing *1 which is mounted in the upper end of the cylinder 3d and which has a packing seal 92 and an O-ring seal 93 associated therewith. A piston rod wiper 94 is provided at the upper end of the bushing 91.

The piston rod 219 is provided at its upper end with an upwardly opening yoke portion 95 in which a sprocket 96 is supported for rotation about a horizontally disposed transversely extending pin 97. A sprocket chain 99 extending over the sprocket as has the lower end of the rearwardly disposed run thereof secured to the frame structure 25, as at 1959, and the lower end of the forwardly disposed run thereof secured to the upper end ofthe fork carriage 66 by a connection between a joining link thereof and a joining block 1412 (FIG. 12) which is welded to the rear surface of the transversely extending front portion 77 of the bracket 67. j

A passage 103 formed in the mounting block plug 87 opens at one end to the lower end of the cylinder 86 with its opposite end being adapted to receive one end of a fluid conduit 104 which is connectable at its opposite end to a source of hydraulic fluid pressure, such as pump means. When hydraulic fluid under pressure is directed into the lower end of the hydraulic cylinder 86, the piston 85 and the sprocket 96 on the upper end of the piston rod 89 are moved upwardly relative to the cylinder 86 with the fork carriage 66 and the lifting fork 82 thus being pulled upwardly in a generally vertical direction by the sprocket chain 99 in an obvious manner. With the chain 9% and sprocket 95 arrangement described herein, the fork carriage 66 and the lifting fork 82 are movable upwardly at twice the rate and twice the distance of the upward movement of the piston 38 in the cylinder 86. When pressure is relieved from the cylinder 86, the piston 88 and the sprocket are permitted to move downwardly whereby to lower the fork carriage 66 and the lifting fork '32. j

The first specific form of the fork liftvehicle of the in vention in which hydraulic fluid under pressure is directed to the hydraulic cylinder 86 by means of a manually operable pump may best be described with reference to 6 FIGS. 13 and 14. In the fork lift vehicle of FIG. 13, the vehicle is propelled by a direct pedal drive through the chain 46 and the

sprockets

45 and 44. A standard hydraulic hand-operable pump 106 of a known type is mounted on the side of the box-like container 38 in a position such that it is readily operable bya person sitting in the seat 39. One manually operable pump 106 which is suitable for use is the commercial model manufactured by Templeton, Kenley & Co. of Broadview,

Illinois, and illustrated in detail in FIG. 14. This pump 1% provides a high volume, low pressure output for raising the lifting fork 82 rapidly under no load conditions and automatically provides a high pressure, low volume output during an actual load lifting operation. As the details of the manually operable pump 106 form no part of the invention, the structure and operation thereof will merely be described herein in a brief manner. The pump 1% includes a hydraulic fluid reservoir portion 107, an inlet-outlet port 198 to which the fluid conduit 104 is connectable, and a reciprocal piston 109 having a large diameter high volume, low pressure portion 110 and a smaller diameter low volume, high pressure portion 111. The larger diameter piston portion has associated therewith a fluid passage connection 112 to the fluid reservoir 187 with an adjustable by-pass valve 113 being provided therein, which valve 113 is normally set at relatively low pressures, and a fluid pass-age connection 114 to the inlet-outlet port 10% with a ball valve arrangement 115 of known type being provided therein. The smaller diameter piston portion 111 has associated therewith a fluid passage connection 116 to the fluid reservoir 1G7 and a fluid passage connection 117 to the inlet-outlet port 108 with a ball valve arrangement 118 of known type being provided therein. The pump 1% is also provided with a manually operable release valve 119 associated with a fluid-return passage connection 120 between the inletoutlet port 1618 and the fluid reservoir 1%37 and with a high pressure safety by-pass valve arrangement lfzl. The piston 109 is reciprocal by means of a pivotally mounted manually pumpable handle 122 which is operably connected to the piston 109 in a known manner and which is readily operable by a person sitting in the seat 39.

When the pump 106 is actuated under a no load condition, both piston portions 110 and 111 are operable to provide high volume, low pressure output. Under loadlifting conditions, the larger diameter piston portion 119 s automatically by-passed at relatively low pressures, for instance 200 p.s.i., by the by-pass valve 113, whereby only the smaller diameter piston portion 111 is operable to provide high pressure, low volume output. To lower the fork carriage 66 and the lifting fork 82, the release valve 119 is manually opened to relieve the pressure in the hydraulic cylinder 86 in an obvious manner.

The second form of the fork lift vehicle of the invention in which hydraulic fluid under pressure is directed to the hydraulic cylinder 86 by an electric motor-driven pump may best be described with reference to FIGS. 15. and 16. It should first be noted that in this second form of the invention, the fork lift vehicleds propelled by the same direct chain and sprocket drive between the footoperated pedals and the front drive axle as previously described for the first form of the invention shown in FIG. 13. As illustrated in FIG. 15, a DC. electric motor 125 and a standard commercial hydraulic pump 126 includmg a built-in hydraulic fluid reservoir portion 127 are mounted on one side of the box-like compartment 38 convenient to a person sitting in the seat 39. Storage batteries (not shown) electrically connected to the DC. electric motor 125 are preferably housed in the box-like compartment 3% beneath the seat 39 whereby they aid in counterbalancinga load on the lifting fork 82 at the forward end of the vehicle.

A schematic diagram of the electrical and hydraulic system for this form of the invention, the details of which form no part of the invention, is illustrated in FIG. 16.

7 As illustrated, the electric motor 125 is drivingly connected to the hydraulic pump 125 which has a fluid inlet connection to the hydraulic fluid reservoir 127 and a fluid outlet connection, including a check valve 123, connectable to the fluid conduit 1 34 which is connected at its opposite end to the hydraulic cylinder 86. The system further includes an adjustable safety pressure relief valve 13%) and a cam-openable release valve 131 for relieving the pressure in the lifting cylinder 86. A two-way control lever 132, positioned for convenient operation by a person in the seat 39, when moved in one direction actuates a starter switch 133 for the electric motor 125 whereby to drive the pump 126 and direct fluid under pressure to the hydraulic cylinder 86 to raise the lifting fork 82. When the control lever 132 is released, it immediately returns to its normal neutral position whereby to stop the motor 125 and the pump 126 with the lifting fork 82 being retained in .a raised position. When the control lever 132 is moved in the opposite direction, the release valve [131 is opened by cam means associated with the control lever 132 whereby to relieve the pressure in the hydraulic cylinder 86 and thereby lower the lifting fork 82.

The third form of the fork lift vehicle of the invention in which hydraulic fluid under pressure is directed to the hydraulic lifting cylinder 86 by a rotatably drivable hydraulic pump which is mechanically connectable to the foot-operated pedals 48 may best be described with reference to FIGS. 17, 18, 19 and 20, FIGS. 17 and 18 being somewhat diagrammatic in nature for purposes of clarity. As best illustrated in FIGS. 18 and 19, the pedal shaft 41 is provided with a longitudinally extending keyway 135 with a pedal gear 136 being keyed thereon in the usual manner and adapted for axial movement between opposite limit positions relative to the pedal shaft 41. In one limit position the pedal gear 136 is meshed in driving engagement with a driven gear 137 and in the opposite limit position the pedal gear 136 is meshed in driving engagement with a driven gear 138. The sprocket chain 46 which extends about the sprocket 44 associated with the front wheel drive axle 3-1 also extends, in this third form of the invention, about a sprocket 139 which is mounted on a shaft 141 for rotation with the driven gear 137 whereby to provide a direct pedal drive to the front wheels 31) when the pedal .gear 136 is meshed in driving engagement with the driven gear 137.

A sprocket 142 is mounted on a shaft 143 for rotation with the driven gear 138 when the pedal gear 136 is meshed in driving engagement therewith. A standard hydraulically drivable hydraulic pump 144 of known type, such as a piston pump, and having a hydraulic fluid reservoir 145 associated therewith has a sprocket 146 mounted on a drive shaft 147 thereof. The pump 144 has an inlet-outlet port (not shown) which is connectable to the fluid conduit 104 which is connected at its opposite end to the hydraulic lifting cylinder 86. A sprocket chain 148 extends about the sprocket 142 associated with the driven gear 138 and about the sprocket 146 associated with the pump 144 whereby the pump 144 is actuated to deliver hydraulic fluid under pressure through the fluid conduit 104 to the hydraulic cylinder 86 when the pedal gear 136 is meshed in driving engagement with the driven gear 138 to raise the fork carriage 66 and the lifting fork 82. The pump 144 is provided with a standard manually operable release valve (not shown) for relieving the pressure in the cylinder 86 to lower the fork carriage 66 and the lifting fork 82.

It is noted, as shown in FIG. 18, that the pedal gear 136 may be axially positioned in a centered position be tween the two limit positions, in which centered position the pedal gear 136 is meshed in driving engagement with both the driven

gears

137 and 138, thus permitting the lifting fork 82 to be raised while the fork lift vehicle is being propelled. Provision is made for selectively shifting the pedal gear 136 between its centered and opposite limit positions by a shifting mechanism which is best illustrated in FIGS. 18, 19 and 20. The shifting mechanism includes a vertically disposed shaft 150 which is mounted adjacent the steering shaft housing 49 for pivoting movement about its longitudinal axis. The upper end of the shaft 151 is rotatably mounted in a bracket 151 attached to the steering shaft housing 49 and the lower end of the shaft 151? has a reduced-in-diameter portion 153 which is rotatably mounted in a bore 154 formed in the top wall 26 of the frame structure 25. A laterally extending arm 1% is rigidly secured to the lower portion of the shaft 151), as by welding, and has a downwardly bent-outer end portion 157 on the lower end of which a hardened steel roller 158 is rotatably mounted in a suitable manner. The roller 158 is received in an annular groove 159 formed in one end of the pedal gear 136 whereby pivoting movement of the vertical shaft 1511 about its longitudinal axis serves to shift the pedal gear 136 between its centered and opposite limit positions. A laterally extending gear shifting lever 168 is secured to the upper portion of the shaft 159 for pivoting same.

The fourth form of the fork lift vehicle of the invention in which the fork carriage 6d and the lifting fork 82 are raised and lowered by the foot-operated pedals 41 through a direct mechanical connection may best be described with reference to- FIGS. 21 and 22. This fourth form of the invention is identical in certain aspects to the third form of the invention illustrated in FIGS. 17 and 18 and incorporates the same gear shifting mechanism illustrated in FIGS. 19 and 20. As illustrated in FIG. 21, the pedal shaft 41 is provided with the pedal gear 136, which is axially shiftable selectively between a centered and opposite limit positions by the previously described gear shifting mechanism, whereby to provide a direct mechanical drive to the sprocket 44 associated with the front wheel drive axle 31 through the driven gear 137, the sprocket 139 and the sprocket chain 46, as in the previously described third form of the invention. This form of the invention further incorporates the driven gear 138, the sprocket 142 associated therewith, and the sprocket chain 148 which extends about the sprocket 142, the driven gear 138 being adapted to be selectively meshed in driving engagement with the pedal gear 136.

In this fourth form of the invention, a pair of horizontal transversely extending

shafts

162 and 163 are mounted at the upper and lower ends, respectively, of the generally vertically disposed guide and support structure 61 with upper and

lower sprockets

164 and 165, respectively, being rotatably mounted thereon approximately midway between the side channel members 62 of the guide and support structure 61. An endless sprocket chain 11% extends about the upper and

lower sprockets

164 and 165 with the fork carriage 66 being securely attached to a link or links on the forwardly disposed run thereof for raising and lowering movement therewith. A drive sprocket 167 is mounted on the lower shaft 163 and has a sprocket chain 168 extending about the same and about a sprocket 169 on an output shaft of a commercial reduction gear box 178 of known type. The sprocket chain 148 which extends about the sprocket 142 associated with the driven gear 138 also extends about a sprocket 172 on an input shaft of the gear box 178, whereby when the pedal gear 136 is meshed in driving engagement with the driven gear 138, the drive sprocket 167 for raising and lowering the lifting fork 82 is mechanically connected to the footoperated pedals 40 through the gear reduction box 170 and the aforementioned chain and sprocket drive arrangements. It is noted that the pedal gear 136 may be axially shifted by the shifting mechanism into either of its limit positions for either raising and lowering the lifting fork 82 or propelling the vehicle separately or into its centered position in which it is meshed in driving engagement with both the driven

gears

137 and 138 whereby to permit raising and lowering the lifting fork 82 while the vehicle is being propelled.

It is noted that in all four forms of the fork lift vehicle of the invention described herein, the vehicle may be propelled and the lifting fork 82 raised and lowered either as separate operations or as simultaneous operations, as desired. It is further noted that in all four forms of the invention, the hollow box-like compartment 38 beneath the seat 39 is intended to be used for adding weight at the rear end of the vehicle as required for counterbalancing a load on the forwardly projecting lifting fork 82. It is still further noted that in all four forms of the invention, all of the chain drives and all of the hydraulic fiuid conduits are disposed within the hollow channehshaped frame structure 25, which feature is important from a standpoint of safety and also results in the fork lift vehicles having a neat clean appearance.

As a result of the manner in which the right-angular members defining the lifting fork 82 are mounted on the rod 80, it is noted that same are freely laterally adjustable thereon whereby the lifting fork 82 is readily adjustable as to width. Of further interest are the uppermost and lowermost lifting positions of the lifting fork 82 as indi cated in broken line in FIG. 1.

With the right-angular members defining the lifting fork 32 being pivotally mounted by their collar portions 85 on the rod 8 3, the lifting fork 82 may be pivoted upwardly and rearwardly into the position indicated in broken line in FIGS. 1 and 23 whereby to substantially shorten the over-all length of the vehicle for greater maneuverability when the lifting fork 82 is not required. This feature, for instance, permits fitting the fork lift vehicle into a small standard elevator for movement between fioor levels. As illustrated in FIG. 23, a transversely extending stop member 175 may be provided on the fork carriage 66 to support the rearwardly turned lifting fork 82 in a horizontal position so that a load may be supported thereon rearwardly of the guide and support structure 61.

It will be understood that certain additional modifications may be made in the construction or arrangement of the fork lift vehicles disclosed herein without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on wheels and characterized by a seat and means for steering the vehicle, a lifting fork mounted on the front end of the frame structure for movement in a generally vertical direction relative thereto, and foot-operated pedals operable from said seat and adapted to be selectively connected mechanically to certain of said wheels through chain and sprocket means for propelling the vehicle and to said lifting fork through chain and sprocket means for raising and lowering said lifting fork.

2. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on wheels and characterized by a seat and means for steering the vehicle, a generally vertically disposed support and guide structure mounted on the forward end of the frame structure, a fork carriage slidably mounted on said vertically disposed support and guide structure for vertical movement relative thereto, first chain and sprocket means associated with said support and guide structure with said chain being vertically movable relative thereto, means connecting said fork carriage to a portion of said chain for vertical movement therewith, a forwardly projecting lifting fork mounted on said fork carriage for vertical movement therewith, and foot-operated pedal means operable from said seat and mechanically connectable through second and third chain and sprocket means, respectively, to said first chain and sprocket means for raising and lowering said fork carriage and to certain of said wheels for propolling the vehicle.

3. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on a pair of front drive wheels and a third turnable rear wheel and characterized by a seat and means connected to said rear wheel for steering the vehicle, a generally vertically disposed channel structure mounted on the forward end of said frame structure, a fork carriage having rollers confined in said vertically disposed channel structure and adapted for vertical movement relative thereto, a pair of sprockets mounted on said vertically disposed channel structure at the upper and lower ends thereof for rotation about generally vertically aligned horizontal axes, a continuous chain extending about said pair of sprockets, means connecting said fork carriage to a forwardly disposed run of said chain for vertical movement therewith, a forwardly projecting lifting fork mounted on said fork carriage for vertical movement therewith, and foot-operated pedals operable from said seat and selectively connectable mechanically to said pair of front drive wheels through chain and sprocket means for propelling the vehicle and to said lower sprocket through separate chain and sprocket means for raising and lowering said lifting fork.

4. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on wheels and characterized by a seat and means for steering the vehicle, a generally vertically disposed support and guide structure mounted on the forward end of the frame structure, a fork carriage slidably mounted on said vertically disposed support and guide structure for vertical movement relative thereto, first chain and sprocket means associated with said support and guide structure with said chain being vertically movable relative thereto, means connecting said fork carriage to a portion of said chain for vertical movement therewith, foot-operated pedal means operable from said seat and mechanically connectable through second and third chain and sprocket means, respectively, to said first chain and sprocket means for raising and lowering said fork carriage and to certain of said wheels for propelling the vehicle, and a forwardly projecting lifting fork pivo-tally mounted on said fork carriage for vertical movement therewith and for pivoting movement about a horizontal axis relative thereto from said forwardly projecting position to a position wherein said lifting fork projects rearwardly of the front end of the vehicle, in which position the over-all length of the vehicle is substantially shortened.

5. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on wheels and characterized by a seat and means for steering the vehicle, a lifting fork mounted on the front end of the frame structure for movement in a generally vertical direction relative thereto, foot-operated pedals operable from said seat and connectable mechanically to certain of said wheels through chain and sprocket means for propelling the vehicle and to said lifting fork through chain and sprocket means for raising and lowering said lifting fork, and a manually operable shifting device for selectively connecting said foot-operated pedals to said wheels and to said lifting fork separately or to both said wheels and lifting fork simultaneously.

6. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on wheels and characterized by a seat and means for steering the vehicle, a generally vertically disposed support and guide structure mounted on the forward end of the frame structure, a fork carriage slidably mounted on said vertically disposed support and guide structure for vertical movement relative thereto, first chain and sprocket means associated with said support and guide structure with said chain being vertically movable relative thereto, means connecting said fork carriage to a portion of said chain for vertical movement therewith, a forwardly projecting lifting fork mounted on said fork carriage for vertical movement therewith, foot-operated pedal means operable from said seat and mechanically connectable through second and third chain and sprocket means, respectively, to said first chain and sprocket means for raising and lowering said l; l fork carriage and to certain of said wheels for propelling the vehicle, and a manually operable shifting device for selectively connecting said foot-operated pedal means to said second and third chain and sprocket means separately or to .both said second and third chain sprocket means simultaneously.

7. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on a pair of front drive wheels and a third turnable rear wheel and characterized by a seat and means connected to said rear wheel for steering the vehicle, a generally vertically disposed channel structure mounted on the forward end of said frame structure, a fork carriage having rollers confined in said vertically disposed channel structure and adapted for vertical movement relative thereto, a pair of sprockets mounted on said vertically disposed channel structure at the upper and lower ends thereof for rotation about generally vertically aligned horizontal axes, a continuous chain extending about said pair of sprockets, means connecting said fork carriage to a forwardly disposed run of said chain for vertical movement therewith, a forwardly projecting lifting fork pivotally mounted on said fork carriage for vertical movement therewith and for pivoting movement relative thereto into a rearwardly projecting position whereby to shorten the over-all length of the vehicle, foot-operated pedals operable from said seat and connectable mechanically to said pair of front drive wheels through chain and sprocket means for propelling the vehicle and to said lower sprocket through separate chain and sprocket means and a reduction gear box for raising and lowering said lifting fork, and a manually operable shifting device disposed adjacent said seat for selectively connecting said foot-operated pedals to said drive wheels and to said lower sprocket separately for propelling the vehicle and for raising and lowering the lifting fork, respectively, and to both said drive wheels and said lower sprocket simultaneously for vertically mov ing said lifting fork during forward or rearwad movement of the vehicle.

3. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on a pair of front drive wheels and a third turnable rear wheel and characterized by a seat and means connected to said rear wheel for steering the vehicle, a generally vertically disposed channel st-ructure mounted on the forward end of said frame structure, a fork carriage having rollers conlined in said vertically disposed channel structure and adapted for vertical movement relative thereto, a vertically disposed hydraulic cylinder and piston unit mounted on the lower portion of said channel structure and hav ing a sprocket mounted on the upper projecting end of a piston rod thereof, a chain extending over said sprocket with its depending rear end secured to said frame structure and with its depending front end connected to said fork carriage whereby upward movement of said piston results in upward movement of said fork carriage relative to said vertically disposed channel structure, a forwardly projecting lifting fork mounted on said fork carriage for vertical movement therewith, a rotatably drivable pump on said frame structure for actuating said hydraulic cylinder and piston unit to move said piston rod and thus said lifting fork upwardly, and foot-operated pedal means operable from said seat and selectively COIll'lfiCifilblE through separate chain and sprocket means simultaneously and separately to said rotatably drivable pump and to said pair of drive wheels whereby to permit moving said lifting fork in a vertical direction while propelling the vehicle, moving said lifting fork in a vertical direction while the vehicle is standing still, and propelling the vehicle with said lifting fork remaining in a desired position.

9. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on a pair of front drive wheels and a third turnable rear wheel and characterized by a seat and means connected to said rear wheel for steering the vehicle, a lifting fork mounted on the front end of the frame structure for linear movement in a generall vertical direction relative to the front end of the frame structure, a hydraulic cylinder and piston device mounted on said frame structure and operably connected for raising and lowering said lifting fork, pump means mounted on said frame structure and operably connected to said hydraulic cylinder and piston device, foot-operated pedals operable from said seat and connecta-ble mechanically through chain and sprocket means to said pair of front drive wheels for propelling the vehicle and to said pump means for operating same whereby to actuate said hydraulic cylinder and piston device to raise and lower said lifting fork, and a manually operable shifting device for selectively connecting said foot-operated pedals to said wheels and to said pump means separately or to both said wheels and said pump means simultane' ously.

19. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on a pair of front drive wheels and a third turnable rear wheel and characterized by a seat and means connected to said rear wheel for steering the vehicle, a generally vertically disposed support and guide structure mounted on the forward end of said frame structure, a fork carriage slidably mounted on said support and guide structure for vertical movement relative thereto, first chain and sprocket means associated with said support and guide structure, hydraulically actuated means operable when actuated to cause vertical movement of a portion of said chain relative to said support and guide structure, means connecting said fork carriage to said chain portion for vertical movement therewith, a forwardly projecting lifting fork mounted on said fork carriage for vertical movement therewith, rotatably driven pump means hydraulically connected to said hydraulically actuated means, foot-operated pedals operable from said seat and connectable mechanically to said pair of front drive wheels through second chain and sprocket means for propelling the vehicle and to said pump means through third chain and sprocket means for rotatably driving same to raise said lifting fork, and a manually operable shifting device disposed adjacent said seat for selectively connecting said footoperated pedals to said wheels and to said pump means separately or to both said wheels and said pump means simultaneously.

11. A relatively lightweight fork lift vehicle comprising, in combination, a frame structure mounted on a pair of front drive wheels and a third turnable rear wheel and characterized by a seat and means connected to said rear wheel for steering the vehicle, a generally vertically disposed channel structure mounted on the forward end of said frame structure, a fork carriage having rollers confined in said vertically disposed channel structure and adapted for vertical movement relative thereto, a vertically disposed hydraulic cylinder and piston unit mounted on the lower portion of said channel structure and having a sprocket mounted on the upper projecting end of a piston rod thereof, a chain extending over said sprocket with its depending rear end secured to said frame structure and with its depending front end connected to said fork carriage whereby upward movement of said piston results in upward movement of said fork carriage relative to said vertically disposed channel structure, a forwardly projecting lifting fork mounted on said fork carriage for vertical movement therewith, a rotatably drivable pump on said frame structure for actuating said hydraulic cylinder and piston unit to move said piston rod and thus said lifting fork upwardly, foot-operated pedal means operable from said seat and selectively mechanically connectable simultaneously and separately to said rotatably drivable pump and to said pair of drive wheels whereby to permit moving said lifting fork in a vertical direction while propelling the vehicle, moving said lifting fork in a vertical direction while the vehicle is standing still, and propelling the vehicle with said lifting fork in a desired position, and a manually operable shifting device disposed adjacent said seat for selectively 2,529,749 11/50 Wade et a1 214-392 connecting said foot-operated pedals through separate 2, 61,576 7/51 Johnson 187-9 chain and sprocket means to both said drive Wheels and 2,709,015 5/55 Sasgen et X said pump simultaneously and to said drive Wheels and 2,910,203 10/ 59 Todd -67 said pump separately, 5 2,919,759 1/60 W h ely 80-53 FOREIGN PATENTS R f C't db th E r e erences 1e y e xamlne 1,164,709 5/58, France UNITED STATES PATENTS 1,229,113 3/60 France. 1,109,424 9/14 Kiefer 280-261 10 615,281 1/49 Great Britain. 1,676,449 7/28 Lederer 18711 X 7 241 7 5 1 Weiss 1 7 9 SAMUEL F. COLEMAN, Primary Examiner.

2,395,345 2/46 Schreck 137-9 ANDRES H. NIELSEN, Examiner.