US3061126A

US3061126A - Fork lift for garden tractor

Info

Publication number: US3061126A
Application number: US26994A
Authority: US
Inventors: Harry A Robinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-05-05
Filing date: 1960-05-05
Publication date: 1962-10-30
Anticipated expiration: 1979-10-30

Description

Oct. .1962 H. A. ROBINSON 3,06 ,1 6

FORK LIFT FOR GARDEN TRACTOR Filed 5 1960 4 Sheets-Sheet 1 Harry A. Robinson 1 N VEN TOR.

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Altman Oct. 30, 1962 H. A. ROBINSON 39 5 FORK LIFT FOR GARDEN TRACTOR Filed May 5, 1960 4 Sheets-Sheet 3 Fig. 5

Harry A. Robinson IN VENTOR.

BY 24mm Wp/W @bt; 30; 11962-5 H=., A ROBINSON mom; um FOR. GARDEN TRACTOR.

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United States Patent Office 3,061,126 Patented Oct. 30, 1962 3,061,126 FORKLIFT FOR GARDEN TRACTOR Harry A. Robinson, 2625 Johnson St., Eikhart, Ind. Filed May 5, 1960, Ser. No. 26,994 8 Claims. (Cl. 214-672) This invention relates to a fork lift mechanism that may be attached to'any garden tractor including all the controls necessary for proper operation of the lift fork.

A primary object of this invention therefore, is to provide a self-contained fork lift mechanism that is readily adaptable to all four wheel garden tractors.

It is a further object of this invention, to provide a fork lift mechanism which is simple to operate and yet accurately controlled.

Another object of this invention in accordance with the foregoing objects, is to provide a fork lift mechanism which is powered from the vehicle to which it is attached and capable of simple and accurate control with little modification of the vehicle structure.

In accordance with the foregoing objects, the lifting fork mechanism in accordance with this invention includes a frame on which the fork member is vertically moved upwardly or downward-1y, said frame being pivotally connected at a forward end of the tractor, its position on the tractor being controlled by a positioning lever which cooperates with a stationary rack mounted on the vehicle to hold the frame in any adjusted position. A forward and'reverse gear box is secured to the frame at the bottom thereof and has a power shaft extending out therefrom at one or the other side for driving connection to the tractor motor by means of a belt and pulley drive, with a belt tightener including an idler pulley yieldably maintaining the belt under tension for all positions of the fork frame, avoiding thereby any slackening of the belt. The gear box includes a pair of opposing gears rotatively fast with the power shaft but slidable with respect thereto, said gears being selectively engageable with an output gear connected to an output shaft extending from the top of the gear box, said output shaft being a screw shaft which is threadedly engaged with the fork so as to raise or lower the fork on the frame upon forward or reverse rotation of the output screw shaft. In order to control the drive of the gear box for forward, neutral and reverse, the opposing gears slidable on the power shaft are movable by means of a cam actuated yoke, said cam being connected to a control shaft extending out of the gear box rearwardly thereof, said control shaft being connected by means of a lever and link to a control lever pivotally mounted on the frame adjacent the top thereof.

These together with other objects and advantages will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings. I

FIGURE 1 is a side elevational view of the forklift mechanism mounted on a garden tractor in accordance with this invention, with parts of the tratcor being broken away. FIGURE 2 is a partial side elevational view from the other side of the tractor.

FIGURE 3 is a rear view of the gear box as mounted on the fork lift frame.

FIGURE 4 is a front view of the fork lift and frame.

FIGURE 5 is a side view with parts shown in section, of the fork lift and frame. 7

FIGURE 6 is a sectional view taken through a pla indicated by section line 66 in FIGURE 4.

FIGURE 7 is a sectional view taken through a plane indicated by section line 7--7 in FIGURE 5.

FIGURE 8 is an enlarged partial view of the-fork lift and frame.

FIGURE 9 is a sectional view taken through a plane indicated by section line 9-9 in FIGURE 8.

FIGURE 10 is a top section view of the forward and reverse gear box.

FIGURE 11 is a rear section view of the forward and reverse gear box.

Referring now to the drawing in detail, the fork lift assembly generally indicated by reference numeral 10 is shown mounted on a tractor vehicle 12 in FIGURE 1. The tractor 12 includes a power unit 14 from which the power is derived for raising and lowering the fork lift as more clearly seen in FIGURE 2. A control lever 16 is provided for controlling the pivotal position of the fork lift frame on the vehicle, while the control lever 18 is provided for controlling the direction of movement of the fork lift on the frame. It will therefore be apparent, that the two control levers 16 and 18 being the only controls necessary for operation of the fork lift mechanism, are within easy grasp of the driver of the tractor seated on seat 2th of the vehicle 12.

The lift fork assembly includes a lift fork 22 which is slidably mounted on a lift fork frame 24. Referring to FIGURES 4, 5, 6, 7, 8 and 9, it will be seen that the lift fork 22 includes a pair of

vertical members

26 and 28 interconnected by a pair of

horizontal members

30 and 32 forming a rigid fork 22. Connected to the

horizontal members

30 and 32 intermediate the

vertical members

26 and 28 is .a slide member 34.

The slide member 34 is guidingly supported by the frame 24 by mean-s of

rollers

36 and 38 rotatably mounted on the slide member 34 by means of inwardly extending portions 40, such guide rollers being secured to the slide member 34 adjacent to the two connections of the slide member 34 to the

horizontal fork members

30 and 32. The rollers are supported on a shaft 42 journaled within portions 40 of the slide 34. The

guide rollers

36 and 38 move within

tracks

44 and 46 formed in the shaft 48 is threadedly engaged with a nut member 54 as:

more clearly seen in FIGURES 6, '7 and 5. The nut member 54 is connected to the fork lift 22 by being connected to 'a bracket member 56 which is connected by means of bolt 58 to a bracket member 60 which is welded or otherwise secured to the slide member 34 of the fork 22. Accordingly, upon rotation of the screw shaft 48 in one direction or the other, the fork will be caused to move upwardly or downwardly relative to the frame 24. g -The screw shaft 43 is therefore driven in both directions by means of a gear box 62 attached adjacent to a lower end of the frame 24 with the screw shaft 4st.- tending into the gear box at the top thereof. As seen in FIGURES 5 and ll,'the lower end of the screw shaft 48 is connected to a bevelgear 64 located within the gear box 62. Arranged perpendicularly to the screw shaft 48 and extending outwardly from either side of the gear box 62, is a power shaft 66. Slidably mounted on the power shaft but rotatively fast therewith, are a pair of opposed bevel gears 63 and 70 which when meshing with output gear 64 will drive it in one or the other direction. The power shaft 66 has a driving pulley wheel '72 connected thereto, said pulley wheel 72 capable of being attached to the power shaft 66 on either side of the gear box 62 depending upon which side a power take-0E from the tractor power unit is available.

In order to control the drive of the output screw shaft 48 and also disengage it from drive completely, a for ward and reverse control cam 74 is provided as seen in FIGURE 11, said cam being connected to a control shaft 76 extending outwardly from the gear box 62 to the rear thereof as seen in FIGURE 10. Slidably mounted on the power shaft 66, is a yoke member 78 as seen in FIG- URES and 11 having

lateral sides

80 and 82 which are engageable with the opposing bevel gears 68 and 70 for shifting thereof in one or the other direction. As seen in FIGURE 11, the cam 74 is in a neutral position wherein the yoke follower member 78 has positioned-both gears 68 and 70 out of engagement with the output bevel gear 64. Upon rotation of the cam 74 in one or the other direction from the neutral position shown in FIG- URE 11, one or the other of the bevel gears 68 and 70 will be in mesh with the output gear 64 to rotate the screw shaft 48 to thereby raise or lower the fork as hereinbefore explained. Connected to the cam control shaft 76 just at the rear of the gear box 62, is a control lever 84 having a pivot connection 86 at one end thereof as shown in FIGURE 10. It should of course be realized that the pivot connection may be placed at the other end of the lever 84 if it is desired to control the lever from said other end. As more clearly seen in FIGURES 1 and 3, the control lever 84 is connected by means of a link 86 to the control lever 18, said control lever 18 also having a guide bar 88 connected thereto which is slidably mounted on the frame 24 for limiting the movement of the lever 18 between its control positions.

The forward and reverse gearing is connected to the tractor power source 14 by means of a belt and pulley drive as more clearly seen in FIGURE 2. The drive pulley 72 connected to the gear box power shaft 66 is drivingly connected to a pulley take-off from the power unit 14, said take-01f pulley 90 and drive pulley 72 having a flexible belt 92 trained thereover. It will be appreciated, that inasmuch as the gear box 62 mounting the drive pulley 72, is secured to the fork lift frame 24, pivotal movement of the frame 24 may tend to slacken or tighten the pulley belt 92. Accordingly, a belt tightener is provided in order to maintain the belt 92 under tension for all positions of the frame 24 and gear box 62, said belt tightener including an idler pulley 94 which is rotatably mounted on a frame 96 said frame 96 being pivotally mounted on the frame 24 and biased upwardly by means of spring 98 so as to tension the belt 92 engaged with the idler pulley 94.

The fork frame 24 is pivotally mounted on the vehicle 12 by means of pivot connection 100. The frame 24 is also connected to the control lever 16 by means of link 102 as shown in FIGURE 1. The lever 16 therefore controls the pivotal position of the fork frame 24, said lever 16 being pivotally connected to the vehicle 12 at pivot connection 104 while the lever is held in adjusted position by means of a releasable detent 106 actuated by a finger button 108, said detent 106 cooperating with an arcuate rack member 110 fixed to the vehicle frame in any suitable manner.

From the foregoing description, operation of the lift fork mechanism will be apparent. The tractor driver in order to engage and lift a load for carrying it away, will atcuate the control lever 16 to tilt the fork frame 24 forwardly for engaging the bottom of the load with the fork blades 22. The tractor is then moved forwardly to engage the load on the fork 22. After positioning the load on top of the lift fork 22, the driver again engages the control lever 16 to tilt or pivot the frame 24 backwardly so as to hold the load on the fork 22. Then, the driver will engage the control lever 18 which has been in neutral position up till now, and cause drive of the screw shaft 48 in one direction in order to raise the fork 22 on the frame 24 to a predetermined height and then return the lever to neutral position for holding the load at said height. The load is thereby lifted and carried by the tractor and may be subsequently lowered and left in a desired position.

It will also be apparent from the foregoing description, that a minimum of vehicle modification is required in order to mount the fork lift mechanism thereon, and that after mounting it will be observed that the control levers 18 and 16 are in positions within ready grasp of the vehicle driver.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A fork lift attachment for a garden tractor type vehicle comprising, frame means pivotally mounted at a forward end of the vehicle, fork means slidably mounted on said frame means, forward and reverse gear means mounted on said frame means independently of the vehicle and operatively connected to said fork means for slidable movement thereof in both directions, transmission means displaceably mounted on said vehicle and operatively connecting said gear means to a source of power for all adjusted positions of the frame means, and mechanical fork control means mounted on the vehicle and operatively connected to said frame means for adjusting the pivotal position of the frame means and fork means relative to the vehicle.

2. The combination as defined in claim 1, including single gear control means operatively connected to said gear means for selective conditioning of said gear means in forward, neutral and reverse, said gear control means including a lever pivotally connected to said frame means extending rearwardly of the vehicle adjacent to the fork control means.

3. The combination as defined in claim 2, wherein said gear means includes a gear box secured to said frame means, a power shaft journaled in said gear box and operatively connected to said transmission means, forward and reverse gears slidably connected to said power shaft and cam means connected to said gear control means for selectively moving said gears into mesh with an output gear operatively connected to said fork means.

4. The combination as defined in claim 3, wherein said transmission means includes a wheel connected to said power shaft, an endless flexible belt drivingly connecting said Wheel to said power source and a belt tightener mounted on the vehicle and maintaining said belt under tension for all positions of the frame means.

5. The combination as defined in claim 4, wherein said fork control means includes a control lever pivotally mouted on the vehicle intermediate the ends thereof and link connected to said frame means.

6. The combination as defined in claim 1, wherein said transmission means includes a flexible endless belt drivingly connecting said gear means to said power source and a belt tightener maintaining said belt under tension in all positions of said frame means.

7. A material handling device for a mobile frame comprising, an elongated upright guide frame, means pivotally securing a lower end of said guide frame to a forward end of said mobile frame, an elevatable carriage movably disposed in said guide frame, a pair of lift arms projecting forwardly of said carriage, an arcuate rack member carried by said mobile frame, a control lever pivotally mounted on said mobile frame and releasably engageable with said arcuate rack member for holding thereof in control positions, an upwardly and forwardly projecting link pivotally connected between said control lever and guide frame above said pivotal securing means, motor means, a belt tightening pulley pivotally mounted on said guide frame, a second drive pulley carried adjacent said lower end of the guide frame, an endless belt extending from said motor means about said pulleys and a reversing drive mounted on said guide frame for pivotal displacement therewith and drivingly connecting said drive pulley to the carriage.

8. In combination with a tractor type of vehicle having a motive source of power rearwardly spaced from a for ward end of the vehicle, a material handling attachment comprising, a guide frame means pivotally connected adjacent a lower end thereof to said vehicle at said forward end, mechanical control means operatively mounted on the vehicle intermediate said forward end and the source of power and operatively connected to the guide frame means for pivotal displacement thereof between adjusted positions, reversing gear means mounted on said guide frame means for pivotal displacement therewith, load lift means slidably mounted on the guide frame means and drivingly connected to the reversing gear means, flexible drive means drivingly connecting said source of power to the reversing gear means, belt tightener means movably mounted on the guide frame means and engageable with the flexible drive means to render the the reversing gear means operative in all adjusted positions thereof and reverse drive control means mounted on the guide frame means and projecting rearwardly therefrom above the reversing gear means for control thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,280,090 Schrottky Sept. 24, 1918 1,526,621 Zaun 'Feb. 17, 1925 2,652,164 Tipps Sept. 15, 1953 2,785,818 Mercier et a1 Mar. 19, 1957 2,788,199 Ankersheil Apr. 9, 1957