US1954980A - Multiple lift truck - Google Patents

Description

4 Sheets-,Sheet l vA, M. BARRETT IULTIPLE LIFT TRUCK Filed Feb. 25, 1930 h @$1 @QN AMM@ *April 17, 1934.

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A. M. BARRETT MULTIPLE LIFT TRUCK Filed Feb. 26, 1930 4 'Sheets-Sheet 2 ITufenr ifm s April 17, 1934.

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A. M. BARRETT 1,954,986 MULTIPLE LIFT TRUCK Filed Feb. 25, 1930 4 Sheets-Sheet 4 jg@ f @sa Patented Apr. 17, 1934 intrest MULTIPLE IFT TRUCK Arthur M. Barrett, Winnetka, Ill., assigner to Barrett-Cravens Company, Chicago, Ill., a corporation of Illinois Application February 26, 1930, Serial No. 431,436

24 Claims.

lvy invention relates to lift trucks of the type comprising a main supporting frame carried upon wheels and arranged to be steered by means of a steering hanme which also serves as a means for operating mechanism for raising a lifting frame or platform Inova-bly supported on the main frame. When the lifting frame or platform is in its lowered position the truck is adapted to be backed under a platform upon which the load to 'be transported has been placed, and then by operating the steering handle from any steering position the platform and load thereon is raised from the floor so that the load can be easily transported from one place to another.

i My invention has to do with improved means for raising the lifting frame and for controlling the lowering thereof, and with improved means for mounting the lifting mechanism on the main frame. My invention also has to do with imfi proved means for supporting the lifting frame on the supporting frame and with improved means for retaining the lifting frame or platform in any of its raised positions. Still further, my present invention has to do with improved means for releasing the retaining means and the lifting means so as to allow the lifting frame and any load that may be thereon to lower. i

Other objects and advantages of my present invention will be apparent to those skilled in the of the following detailed description of one embodiment of the same, together with the accompanying drawings illustrating such embodiment and in which:

Figure 1 is a top or plan View of the preferred form of my invention;

Figure 2 is a fragmentary sectional View, on an enlarged scale, taken substantially on the line 2--2 of Figure 1;

1) Figure S is a sectional View, on an enlarged scale, taken on the line 3 3 of Figure 1;

Figure 4 is a View partly in section and partly in elevation and showing on an enlarged scale a portion of the manually operated releasing 3 means for throwing the lifting pawls and the retaining pawl out of operative engagement;

Figure 5 is a side elevation on the same scale as Figure l and showing some parts broken away to better disclose some of the lifting mechanism and the supporting means for the lifting frame;

Figure 6 is an enlarged detail view on the line 6-6 of Figure 3 showing one of the links connecting the steering handle with the lifting mechanism, which link is oscillatable with respect to 3 Vthe lifting mechanism;

art to which it appertains after a consideration Figure 'Z is a cross section lookingrearwardly and taken on the line 7-7 of Figure 1; l

Figure 8 is a section taken on the line 8-8 of Figure 1; and

Figure 9 is an enlarged section taken substantially on the line 9---9l of Figure 1.

Referring now to the drawings, the main or supporting frame 1 is seen to comprise side bars 2 and 3 connected together at their front ends by a crosshead 4. The rearward ends of the side bars 2 and 3 are each bent downward, as at 6 and 7, and are apertured to receive the lower rear axle 8. As best shown in Figures 1 and 5, the side bars 2 and 3 are connected to the crosshead 4 by means of bolts 10 and 11. each of the side bars 2 and 3 and the crosshead 4 and pivoted on the bolts l0 is a pair of front links 12 whose purpose will be described later.

The other bolts l1 securing the front ends of the bars 2 and 3 include appropriate spacing r means (not shown) to space the side bars from the crosshead 4 a distance corresponding to the thickness of the front links 12 pivoted on the bolts 10.

The crosshead 4 is seen to comprise a front portion upwardly arched, as at 15, and which is provided with an intermediate enlarged section which isrformed to provide bearing bosses 17 and' 18 affording a vertical journal for the front king bolt 20. At its lower end the king bolt 20 is provided with a fiange 21 which serves as a seat for the roller bearing assembly 23. At the lower end of the king bolt 20 and below the flange 21 there is provided a pair of forked extensions 25 which are joined by a horizontal web 26 at their" lower ends and which are apertured to receive the front axle 27. Journaled on the front axle 27 is a pair of front steering wheels 28.

Between Secured to the top of the king bolt 20, as by a clamping bolt 30, is a cap 32 which is provided with a ange 33 bearing against the top of the `bearing boss 18 and which serves to hold the king bolt 20 in the crosshead 4. Extending forwardly and upwardly of the king bolt cap 32 is a pair of apertured ears 35 adapted to receive the pivot bolt 37 therethrough. 5

The pivot bolt 37 defines the horizontal axis about which the steering handle has vertical swinging movement and which is thereby pive o'tally secured to the cap 32. Since the king bolt 2) and the cap 32 secured thereto is rotatable about a vertical axis it is obvious that the steering handle 4.0 can be turned laterally to` position the steering wheels 28' for the purpose of guiding the truck. The handle 40 may also be provided with a handle grip (not shown) at its outer end and which serves as a convenient means for pulling the truck from place to place.

The lower rear axle 8 at the rear ends of the side bars 2 and 3 carries in the usual manner the supporting wheels e4.

The upper lifting frame or platform comprises the substantially U-shaped member 50, preferably formed from a metal bar of suitable dimensions, and the forward ends of the U-shaped member are connected to the front links 12 by means of bolts 51 or the equivalent. Near the rear end of the upper lifting frame or platform 50 there is provided a transverse angle member 52 welded or otherwise secured thereto and so arranged therein that the flanges of the angle member 52 extend forwardly and downwardly respectively.

Rear links 54 are secured to the axle 8 at their lower ends and to a transversely bearing member 55 at their upper ends. As clearly shown in Figures 1 and 5 the bearing member 55 is received in the angle of the member 52 in such a manner that the bearing member 55 has supporting contact throughout substantially its entire length, thus providing a wide bearing .for supporting the rear end of the upper lifting frame or platform 50. This supporting bearing structure is further strengthened by means of struts 56 which are clamped, as by bolts 57, to the lower rear axle 8, these struts 56 also being secured to the transversely extending bearing member 55 as by welding. From Figure l it will be noted that the supporting wheels 44 are positioned between one of the rear links 54 and one of the struts 56. This provides a. very strong and sturdy rear axle construction and makes for a long lived truck.

The platform 50 adapted to be raised and lowered with respect to the main supporting frame l, and it will be noted from Figure 5 that the front links 12 and the rear links 54 extend diagonally upwardly and rearwardly of the main frame l and in substantial parallelism with `one another. If, for example, the platform 50 were moved longitudinally forward from the position where it rests Yupon the main supporting frame 1 as shown in Figure 5 the platform 50 would also be elevated with respect to the main frame 1 by virtue of the links 12 and 54 swinging forwardly and upwardly a counter-clockwise direction as shown in Figure 5.`

, My present invention contemplates the provision of an improved means for effecting such lifting movement, and such improved means will now be described.

A pair of Shaft bearing brackets 60 is bolted to the lower supporting frame, which bearing brackets provide journals' for rotatably support ing the main shaft 61, see Figure 1. A lifting crank 63 is keyed or otherwise secured to either end of the main shaft 61 and in a positionto lie closely adjacent to the side ` bars 2 and 3 and the I forwardly extending bars of the Ushaped upper lifting frame or platform 56. Each of the cranks 63 is connected to the platform by an upwardly and forwardly extending lifting link 65, the lifting link 65 being connected to the crank 63 by means of a lifting crank pin 66 and to the platform 50 by means of a bolt 68.

The main shaft 61 is adapted to be rotated by a lifting ratchet 76 keyed thereto as indicated in Figure 3. Journaled on the main shaft 61 and embracing the lifting ratchet 70 is a pair of lifting arms or levers 71 connected to operate together by means of connecting shafts 72 and 73, the latter of which may be termed a lifting pawl shaft since there is mounted thereon a pair of pawls 75 which are journaled thereon and adapted to engage the teeth 76 formed on the lifting ratchet 70. Each of the pawls 75 is weighted, as at 78, so as to be continually biased toward engagement with the teeth 76 on the ratchet member 70.

kEach of the pawls 75 is also provided with an inwardly extending lug 79 for a purpose to be later described.

The forward ends of the lifting arms or levers are connected together by the shaft 72, as indicated in Figures 3 and 6. My present invention contemplates connecting the lifting levers 7l to the vertically swinging handle member ll0 so that when the handle 40 is oscillated up and down the lifting levers are adapted to cause the ratchet 70 to turn the shaft 61 and the cranks 63 connected therewith so as to exert a force through the lifting links 65 to move the lifting platform 50 forwardly and upwardly with respect to the main supporting frame l. The connecting means between the handle 40 and the lifting arms or levers 71 is seen to comprise a series of connected elements one of which is the double link 86 having a hook 8l at its lower end which has engagement with the connecting shaft 72. The double link 80 is held on the shaft 72 by the bolt 82. As is shown in Figure 6, the hook 81 is so formed that the double link 80 is capable of swinging laterally with respect to the lifting arms or levers 71. The upper end of the double link 80 is provided with an eye 83 which receives the lifting lever 85. The lifting lever 85 is provided with a lower curved portion 86 adapted 'to operate within the eye 83 of the double link 8G. The lifting lever 85 is pivoted to the king bolt cap 32`by the pivot bolt 37 which also pivotally secures the handle 40 to the outstanding ears 35 provided on the cap 32, see Figure 3.

The upper end of the lifting lever 85 is formed with a bend 87 adapted to be latched to the handle 40 so that vertical oscillations of the handle 40 may beV communicated to the lifting lever 85. When the latter' is thus oscillated the double link 80 exerts a lifting force on 'the lifting arms or levers 7l which, in turn, is transmitted through the shaft 6l and the cranks 63 to the lifting links 65 and lateral movement which the double link 86 is capable of, relative to the lifting levers 71, the handle 40 can be actuated to operate the lifting mechanism in any normal steering position.

That is, the handle 40 need not be brought into t longitudinal alignment with the truck before the platform 56 can be elevated, as is necessary in some trucks in use at present, but the handle may be turned through 180 or more when steering the truck, and in any position within this l range it is operative to lift the platform.

The lifting frame or platform 56 is held in any of its elevated positions by a pawl and ratchet mechanism connected to operate between the lifting ratchet 70 and the lower main frame l, Referring to Figures 2 and 3 it will be noted that the lifting ratchet 70 is provided with a pair of rearwardly extending ears 96 having apertures to receive a hinge 91. A check hinge 62 is pivotally mounted on the the ears 90, and flxedly secured to the check hinge, as by welding, is the tube or cylinder 93. Threadedly secured to the cylinder 93 is the auxiliary chamber 94 for holding a supply of oil therein and having at its rearward end an the platform 50. By virtue of the J, lli

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hinge pin 91 between apertured boss 96 through which passes theV piston rod 98. The chamber 94 is held xed to the cylinder 93 by the lock nut 95. A piston structure 99, including a valve disc 100 slidable on the reduced end 98 ofthe piston rod 98 and a valve 101 xed to the piston rod 98, is carried at the forward end of the piston rod 98 and operates in the cylinder 93. The forward portion of the piston rod 98 is provided with screw threads having a steep pitch `and which are operatively associated with a screw nut 102 securely held between the cylinder 93 and the chamber 94. The nut 102 is prevented from turning relative to the cylinder 93 by being formed with a slot or recess' 103 in which is received the tongue or projection 104 formed on the cylinder 93.

It will therefore be seen that relative longitudinal movement between the cylinder and chamber structure and the piston rod 98 will occasion a rotary movement of the latter.

The rear end of the piston rod 98 is mounted' in a bearing which allows for both rotary movement of the piston rod 98 and also swinging movement thereon, which bearing is seen to comprise the bearing mounting 105 securely bolted or otherwise fixed to a transverse angle member 106 mounted on lower main frame 1 between the side bars 2 and 3. n addition to the bearing mounting 105, the bearing referred to above also includes the bearing. adapter 107 secured to the end 108 of the piston rod 98 by means of a pair of nuts 110 threaded onto lthe piston rod 98. Between the adapter 107 and the mounting 105 is an inner ring 109er, an outer ring 1095 and an assembly of antifriction rolls 114 so formed and arranged that the piston rod 98 is capable of a limited amount o f up and down swinging while, at the same time, being rotatably mounted in the bearing mounting 105 on the supporting frame 1.

A bearing mounting cap 112 is secured to the bearing mounting 105 by means of four bolts 113,

Vand the cap 112 is provided interiorly with thrust bearings 115 cooperating with the forward surface of the adapter 107 to maintain the piston rod 98 in proper position relative to the bearings 114.

The forward portion of thecap 112 is formed to be spherical about the virtual point of up and down swinging of thepiston rod 98 and is arranged to cooperate with the similarly formed extension 117 provided on the check ratchet 120.

The spherical portion of the extension 117 is provided with a number of oil retaining grooves 118.

Referring now to Figures 1 and 7, it will be observed that the bearing mounting 105 is provided with a lateral extension 125 havingV a pair of forwardly extending apertured ears 126 and a boss 127 which provides a support for the forwardly extending pin 128 secured therein. Mounted on the pin 128 and extending adjacent to the ears 126 is the check pawl 130 having a weighted extension 131 so that the pawl 130`is urged toward engaging position with the check ratchet 120 mounted on the piston rod 98 to turn therewith. A set screw 132 serves to secure the check ratchet 120 to the piston rod 98. The check ratchet 120 may also be keyed to the piston rod 98, as by a key 133.

The operation of the machine as thus far described is as follows. When the lifting lever 85 islatched to the handle 40, the latch 135 being pivoted on the handle for that purpose, one downward sweep of the handle will raise the double linl; 80 which, in turn, will rock the liftingarmsf 71 about their axis on the shaft 61 and, through the lifting pawls 75, turn `the lifting ratchet in a clockwise direction as viewed in Figure 3.

This will cause the cranks 63 to be turned in the same direction and to exert a forward and upward force through the lifting links to the platform 50 to elevate the same a certain amount. The clockwise rotation of the lifting ratchet will, however, move the check tube 93 and chamber 94 forward with respect to the piston rod 98, the latter being held from forward movement by the thrust bearing` 115 and the cap 112. The forward movement of the mainV screw nut 102 along the piston rod 98 will cause the latter to turn carrying with it the check; ratchet 120, turning the latter in a counter-clockwise direction as viewed in Figure 7. When the lifting frame 50 is thus elevated above its lowermost position the check pawl 130 will prevent the clockwise rotation of the check ratchet 120 and thus hold the platform 50 in its raised position. The handle 40 is then raised which allows the double link. to move downwardly carrying with it the lifting arms or levers 71, the lifting pawls 75 moving freely over the teeth 76 of the lifting ratchet 70.

The handle 40 may then be given another downward movement whereupon the lifting pawls 75 will engage with the lifting ratchet 70 to rock the shaft 61 and raise the platform 50 to another position. Further forward movement of the nut 102 along the piston rod 98 will occasion a further rotation of the check ratchet 120 so that when the handle 40 is brought to its lowered position the second time the check pawl 130 again engages and holds the check ratchet 120 from returning.

The relation between the number of teeth on the lifting and holding ratchets and the pitch of threadson the piston rod 98 is such that for a movement of the lifting arms through a distance of one tooth of the lifting ratchet the check ratchet is rotated through a distance equal to several teeth thereon, whereby the lifting platform is held in positions intermediate the positions to which it is raised by an advance equal to one tooth on the lifting ratchet.

4Thus it will be clear that the handle 40 may be oscillated up and down any number of times that it is necessary to elevate the platform 50 and the load thereon to its maximum raised position, the check pawl and associated structure effectively holding the platform 50 and load at any of its raised positions.

When the load has been raised and the truck transported to the desired position it then becomes necessary to release the means holding the platform 50 in its elevated position and I will now describe the improved means I have provided to secure this result. 1t must be remembered that in order to allow the load to lower it is necessary not only to release the holding pawl'130 but also the lifting pawls 75. The crosshead 4 is provided with a pair of rearwardly extending apertured ears carrying a pin 141 held therein by means of cotter keys 142, and the pin 141 provides a pivotal support for afoot treadle 144 having three arms.

One ofthe arms, 145, extends forwardly for'convenient operation by the foot of the operator in releasing the pawls to allow the load to lower, an-

other of the arms, 146, extendsrearwardly and is "f adapted to be pressed by the foot of the operator when it is desired to return the lifting pawls and the retaining pawls to their operative positions,

andthe third arm, 147, extends downwardly and is connected by means of the 1ink'150v to a pawlzrelease cam lever 151 which is pinned to the short shaft 153, see Figure 4.

This shaft 153 is journaled in a pawl release cam bearing 154 supported on the main shaft 61. 'Ihe pawl release cam bearing 154 is, however, held from rotation with the main shaft 61 by the cam bearing brace 155 which is bolted to the lower portion of the pawl release cam bearing 154 and extends upwardly and forwardly for connection through the crosshead 4 at 156. Secured to the inner end of the shaft 153 is the pawl release cani 169, and which is arranged to move thereagainst and raise the pawl release arm 161 which is Xedly secured to the pawl stripper shaft 73 rotatable in the lifting arms 71. Collars 163 are pinned or otherwise secured to either end of the shaft '73, as shown in Figure 9. Secured to the shaft '78, as by welding or the like, is the pawl stripper 165, and as shown in Figure 9, the pawl stripper 165 is mounted between the lifting pawls 75 and extends upwardly from the shaft 73 to a position for operative engagement with the lugs 79.

Referring now to Figure 4, it will be obvious that when the treadle 144 is operated by stepping on the arm 145 to depress the same the link 159 will be urged to the right in Figure 4 to rock the pawl release cam lever 151 in a clockwise direction which, through the short shaft 153, rotates the pawl release cam 160 in the same direction.

This rotation of the cam 160 causes the same to move up into engagement with the pawl release arm 161 and to rock the same and the shaft 73 connected therewith in a counter-clockwise direction. Such rotation of the shaft 73 will carry with it the pawl stripper 165, see Figure 3, which will bear against the lugs '79 to move the lifting pawls out of engagement with the teeth 76 of the lifting ratchet 79. Thus the lifting ratchet 70 will be free to turn in a counter-clockwise direction as viewed in Figure 3 to allow the platform to lower.

The platform 50 will not lower however until the check pawl 130 is released from engagement with the check ratchet 126. As will be seen from Figures 1, 4 and 7, a link 170 extends rearwardly from the point of connection of the link 150 with the pawl release cam lever 151, see also Figure 8, and is connected at its rearward end with the check pawl stripper 171 at the lower end thereof. The check pawl stripper 171 is provided with an upper forwardly extending finger 172 adapted to contact with the abutment 173 formed on the check pawl 139 as shown in Figure 7. The check pawl stripper 171 is pivotally mounted between the ears 126. It is thus evident that whenever the foot treadle arm 145 is depressed to release the lifting pawls 75 the link 170 is moved rearwardly to rock the check pawl stripper 171 to cause the saine to depress the abutment 1'73 and move the check pawl 130 out of engagement with the check ratchet 120.

Thus the platform 50 and any load thereon will move downwardly under the action of gravity.

Under most conditions it is desirable to provide some means for cushioning the return of the load and platform 50 to its lowered position. Referring now to Figure 2 it will be clear that when the platform 59 moves downwardly the ,lifting ratchet 79, see Figure 3, will be rotated in a counter-clockwise direction and thus cause the check tube 93 and chamber 94 to move to the right as viewed in Figure 2. Thus the piston 99 will be moved, that is relative to the check tube or cylinder 93, toward the closed end of the cylinder 93. I propose to ll the cylinder 93 with lubricating oil or other fluid of suitable characteristics and to provide a restricted passage for the oil so that when the piston 99 moves toward the closed end of the cylinder 93 considerable resistance will be encountered due to the friction of the oil flowing through the restricted passage from in front of the piston 99. In order, however, that such resistance will not be encountered in lifting the platform 50 I provide for removing the restriction to the flow of oil when the platform is raised. Referring to Figure 2 it will be noted that there is a limited amount of movement of the valve disc 100 along the reduced end 98 of the piston rod 98, soy that when the cylinder 93 is drawn to the left in Figure 2, the disc 100 is moved away from the valve 101, which is smaller than the cylinder 93, so that the oil may flow freely around between the valve 191 and the disc 100 and then through the clearance 100 between the disc 100 and the end 98 of the piston rod 98 to fill the space to the left of the piston 99 in Figure 2. When, however, the cylinder 93 is moved to the right, as when the platform 59 lowers, the disc 100 is moved against the valve 101 so that now the oil must flow through the restricted opening 101' in the valve 101, thus effectively cushioning the return of the platform.

A passage 175 is provided in the main screw nut 192 andV is for the purpose of affording communication between the rearward end of the cylinder 93 and the auxiliary chamber 94 so that oil from the latter may flow into the cylinder 93. In conjunction with the boss 96 formed at the rearward end of the chamber 94 I provide a gland 190 and a packing 181 surrounding the piston rod 98 so that the chamber 94 is substantially leakproof. I also provide a spring 182 biased between the main screw nut 192 and the gland 189 for the purpose of continually urging the latter against the packing 181 to force the same against the piston rod 98.

Attention is directed to Figures 4 and 5 wherein will be noted that the pawl release arm 161 is of such a length that the pawl release cam may be moved to a position substantially at right angles to the cam surface of said release arm, this being for the purpose of allowing the foot treadle 144 and pawl releasing mechanism associated therewith to remain in pawl releasing position. When it is desired to return the pawls to holding position the arm 146 is depressed by the foot of the operator to rock the foot treadle 144 in a clockwise direction as shown in Figure 4 to thereby return the pawl release cam 160 from holding position to the position indicated in Figure 4. rThis movement will also allow the check pawl 130 to return to the position shown in Figure 7.

In handling heavy loads the retaining mechanisin and the cushioning means is subjected to considerable strain, and I propose to strengthen the angle member 106 by the use of diagonal braces 109 and side plates 111 all securely welded or otherwise rigidly fastened together and which may be bolted to the side bars 2 and 3 by the means of bolts 116.

When it is necessary to allow the platform 50 to return to lowered position without load the resistance encounteredr by virtue of the cushioning means is usually great enough to prevent the speedy return of the lifting frame or platform 50.

In order to hasten the return when there is no load on the truck I provide a pair of springs 185 acting between the transverse angle member 106 on the main or supporting frame 1 and brackets 186 on the lifting frame 50 as shown in Figure 1, to move the latter rearwardly and thus aid to swing the same on the links 12 and 54 to its lowered position. Thus when the platform 50 is raised the springs 185 are placed under tension and which when the pawls are released aid in lowering the platform. The springs 185 may be secured to the angle member 106 and the brackets 186 by having ends passed through holes therein.

While I have described, in connection with the accompanying drawings, the specific form in which I prefer to embody my invention, it is to be understood that the invention is not to be limited to the specific means which I have herein shown and described, and that, in fact, widely different means may be employed in the practice of the broader aspects of my invention.

What I claim, therefore, and desire to secure by Letters Patent is:

l. A lift truck comprising the combination of wheeled supporting means, a lifting frame, means for raising the lifting frame, and means for retaining the lifting frame in any raised position including a ratchet mounted on the wheeled supporting means for both pivotal and rotational movement.

2. A lift truck comprising the combination of supporting means, a platform elevatable with respect thereto, means for lifting the platform comprising a shaft journaled on the supporting means, a ratchet secured thereto, a manually operated lever, a lifting lever mounted on said shaft and having pawl means to actuate the ratchet, means comprising a series of links having limited lateral movement and adapted to operatively connect the two levers, and releasable means to retain the platform in elevated position.

3. A lift truck comprising the combination of supporting means, a platform elevatable with respect thereto, means for lifting the platform comprising a shaft journaled on the supporting means, a ratchet secured thereto, a manually operated lever, a pair of lifting levers journaled on said shaft and having pawl means to actuate the ratchet, said levers extending outwardly beyond said pawl means, means connecting the outwardly extended ends of said pair of lifting levers, and means adapted to connect the aforesaid means joining said extended ends of the lifting levers with said manually operated lever, said last means being carried by the manually operated lever and the lifting levers.

4. A lift truck comprising a supporting frame and a lifting platform, a plurality of swinging links supporting the platform on the frame, a shaft journaled on the frame, cranks on the shaft, links connecting the cranks with the platform, means to rotate the shaft, including a ratchet secured to the shaft, a lifting lever journaled to turn about the shaft, a ratchet engaging pawl on said lever, means to oscillate the lifting lever to raise the platform, and manually operative means to release said pawl to allow the platform to lower, said last named means including a member journaled on said shaft.

5. A lift truck comprising a supportingfframe and a lifting platform, a plurality of swinging links supporting the platform on the frame, a

shaft journaled on the frame, cranks on the shaft,

links connecting the cranks with the platform, means to rotate the shaft, including a ratchet secured to the shaft, a lifting lever journaled to turn about the shaft, a ratchet engaging pawl on said lever, means to oscillate the lifting lever to raise the platform, and manually operative means to release said pawl to allow the platform to lower, said last named means including a member journaled on said shaft, a pawl stripper pivoted on said member, and means to hold said member from turning with the shaft.

6. A lift truck comprising a supporting frame and a lifting platform, a plurality of swinging links supporting the platform on the frame, a shaft journaled cn the frame, cranks on the shaft, links connecting the cranks with the platform, means to rotate the shaft, including a ratchet secured to the shaft, a lifting lever journalcd to turn about the shaft, a ratchet engaging pawl on said lever, means to oscillate the lifting lever to raise the platform, pawl and ratchet means to retain the platform in elevated position, and means to release the pawls of the lifting means and the retaining means to allow the platform to lower, said means comprising a foot treadle mounted on the supporting frame, a member journaled on said shaft and having a pawl stripper pivoted thereto in operative relation with the pawl of the lifting means, means including a link connecting said foot treadle and said pawl stripper, and means including a second link connected with the first link to release the pawl of the retaining means whenever the foot treadle is operated to actuate the pawl stripper. l

A lift truck comprising a supporting frame and a lifting platform, a plurality of swinging links supporting the platform on the frame, a shaft journaled on the frame, cranks on the shaft, links connecting the cranks with the platform, means to rotate the shaft, including a ratchet secured to the shaft, a lifting lever journaled to turn about the shaft, a ratchet engaging pawl on said lever, means to oscillate the lifting lever to raise the platform, pawl and ratchet means to retain the platform in elevated position, and means to release the pawls of the lifting means and the retaining means to allow the platform to lower, said means comprising a foot treadle mounted on the supporting frame, a member journaled on said shaft and having a pawl stripper pivoted thereto in operative relation with the pawl of the lifting means, means including d@25 a link connecting said foot treadle and said pawl stripper, means including a second link connected with the first link to release the pawl of the retaining means whenever the foot treadle is operated to actuate the pawl stripper, and a link brace .30 connected to the frame and to the member for rigidly connecting the member to the frame.

8. A lift truck comprising the combination of a wheel supported main frame, a lifting frame carried thereon, a steering handle mounted on 335 one of the frames, lifting means adapted to elevate said lifting frame relative to the main frame and actuated by the steering handle, including pawl and ratchet mechanism and laterally movable links to connect the mechanism to the steer- M@ ing handle, and means to hold the lifting frame in any of its elevated positions, said means comprising a rotatable ratchet on the main frame and means to rotate the ratchet in accordance with the elevation of the lifting means, said last M5 named means being actuated by the lifting means.

9. A lift truck comprising, in combination, main and lifting frames, lifting means `comprising pawl and ratchet mechanism for elevating the lifting frame and including a vertically oscil- 150 latable lifting lever having a pawl, a handle pivoted to one of the frames for steering the truck and for actuating the lifting cans, and meansl including a link connected to the lifting lever for 1both lateral and fore and aft swinging for actuating the lifting means from the handle.

10. A lift truck comprising, in combination, wheeled supporting means, a lifting frame, pawl and ratchet mechanism for elevating the lifting frame relative to said supporting means and including a pair of vertically swinging lifting levers, a pin connecting the outer ends of said lifting levers, a link journaled on the pin and capable of limited lateral swinging relative thereto, a steering handlemounted on the wheeled supporting means for both lateral and vertical swinging, and means connecting the handle with said link. 11A lift truck comprising the combination of a main frame, a lifting frame, means for raising the lifting frame, and means for retaining the lifting frame in elevated position including a pawl and ratchet mechanism, a shaft driven from the lifting means, and a bearing on the main frame for one end of the shaft comprising relatively stationary and movable members allowing both pivotal and rotational movement of the shaft.

12. A lift truck comprising the combination of a main frame, a lifting frame, means for raising ,30,

the lifting frame, and means for retaining the lifting frame in elevated position including a pawl and ratchet mechanism, a shaft, a bearing comprising a spherical race mounted on the shaft, a

bearing mounting on the main frame, a race carried on the mounting, and antifriction rollers cooperating with the races, said races and rollers being formed to allow swinging movement of the shaft, and a thrust bearing cooperating with said first named bearing.

13. In a lift truck having wheeled supporting means, a lifting frame, and means to elevate the lifting frame relative to the wheeled supporting means, means to cushion the return of the lifting frame to lowered position comprising a uid `45,

cylinder and piston, and an auxiliary chamber in communication with said cylinder.

14. In a lift truck having a main frame, a

lifting frame, and means to elevate the liftingV frame relative to the main frame, means to cushion the return of the lifting frame to lowered position comprising a fluid cylinder pivotally connected with the elevating means, a piston in said cylinder, a piston rod movable in the cylinder, means including a swingable roller bearing connecting the piston rod with the main frame, andplatform retaining means connected with the piston rod. Y

l5. In a lift truck having a main frame, a lifting frame, and means to elevate the lifting frame relative to the main frame, means to cushion the return of the lifting frame to lowered position comprising a fluid cylinder pivotally connected with the elevating means, a piston in said cylinder7 apiston rod connected to the piston and to the main frame, and a roller bearing assembly supporting the rear end of the piston rod on the main frame, said cylinder being adapted to move outwardly of the piston rod when the platform is raised.

16. In a lift truck having Wheeled supporting means, a lifting frame, and means to elevate the lifting frame relative to the wheeled supporting means, means to cushion the return of the lifting frame to lowered position comprising a uid cylinder, a piston and piston rod slidable within the cylinder and connected with the supporting means, liquid within the cylinder on both sides of the piston, said piston having a restricted opening therethrough so that the movement of the piston toward the closed end is opposed, and an auxiliary chamber connected with the other end of the cylinder and adapted to supply liquid to said cylinder.

17. A lift truck comprising the combination of wheeled supporting means, a platform elevatable with respect thereto, means for lifting the platform comprising a ratchet journaled on said wheeled supporting means, means connecting the ratchet with the platform, a lifting lever having pawl means to actuate the ratchet, a manually operated lever, and means comprising a series of links having limited lateral movement and adapted to operatively connect the two levers.

18. A lift truck comprising a supporting frame, a platform elevatable with respect thereto, means for lifting the platform comprising a shaft journaled on the supporting frame, a ratchet secured thereto, a manually operated lifting handle including a U-shaped lifting lever, a second lifting lever mounted on said shaft and having pawl means to actuate the ratchet, and a single link means connecting said two lifting levers.

19. A lift truck comprising wheeled supporting means, a platform elevatable with respect thereto, and means for lifting the platform .comprising a lifting handle movable about a vertical axis, a forwardly and upwardly extending link having its upper end connected with the handle and movable vertically thereby in line with said axis, and means pivotally connecting the lower end of said link with the platform.

20. A lift truck comprising the combination of a main frame, a lifting frame mounted on the main frame to swing forwardly and upwardly, supporting and steering wheels for the main frame, a king bolt journaled in the main frame and on which the steering wheels are mounted, a lifting lever connected to the upper end of the king bolt and pivoted to swing vertically, a downwardly and rearwardly extending link having its i upper end carried on said lifting lever and movable thereby substantially vertically in the pivotal axis'of the king bolt, and means operatively connecting the lower end of said link with said platform.

21. A lift truck comprising the combination of a supporting frame, a platform elevatable with respect thereto, means for lifting the platform comprising a shaft journaled on the supporting frame, a ratchet secured thereto, a manually operated lever, a lifting lever mounted on said shaft and having pawl means to actuate the ratchet, and means connecting said levers including a link having its forward end movable substantially vertically by said manually operated lever and its lower end connected with said lifting lever to swing arcuately therewith.

22. A lift truck comprising a supporting frame and a lifting platform, a plurality of swinging links supporting the platform on the frame, a

steering lever for the truck, a shaft journaled on the frame, cranks on the shaft directly connected with the outer ends thereof, links connecting the cranks with the platform, and means to rotate the shaft including a ratchet secured to the shaft,

a lifting lever journaled to turn about the shaft, a ratchet engaging pawl on said lever, a link connected to said steering lever and said lifting lever, whereby operation of said steering lever causes said pawl to engage the ratchet and turn icc said shaft, and means for holding the lifting platform at any one of a plurality of positions intermediate the engagement of said pawl with successive teeth on said ratchet.

23. A lift truck comprising a supporting means, platform elevatable with respect thereto, mechanism for lifting the platform, a manually operated lifting handle swingable about a vertical axis and including a lifting lever having a curved portion, and a single link means connecting the curved portion of said lifting lever with said mechanism, said curved portion being formed so that said link means moves substantially vertically along said axis.

24. A lift truck comprising the combination of a main frame, a lifting frame mounted on the main frame to swing forwardly and upwardly, supporting and steering wheels for the main frame, a king bolt journaled in the main frame and on which the steering wheels are mounted, a manually operated liftinglhandle including a U-shaped lifting lever connected to the upper end of the king bolt and pivoted to swing vertically, a lifting link connected at its forward end with said U-shaped lifting lever, said forward end being moved vertically thereby in line with the axis of the king bolt, and means connected with the other end of the lifting link for raising the lifting frame.

ARTHUR M. BARRETT.

CERTIFICATE OF CORRECTIN.

Patent No. 1,954,980. April 17, 1934,

ARTHUR M. BARRETT.

1t is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, line 145, claim 8, for "means" read frame; and that the said Letters Fatent should be read with this correction therein that the same may conform to the record of the ense in the Patent Office.

Signed and sealed this 19th day of june, A. D. 1934.

Bryan M. Battey (Seal) Acting Commissioner of Patentse

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