US2367061A

US2367061A - Lift truck

Info

Publication number: US2367061A
Application number: US457729A
Authority: US
Inventors: Charles S Schroeder
Original assignee: Yale and Towne Manufacturing Co
Current assignee: Yale and Towne Manufacturing Co
Priority date: 1942-09-09
Filing date: 1942-09-09
Publication date: 1945-01-09
Anticipated expiration: 1962-01-09

Description

Jan. 9, l945.

C. s. SCHROEDER LIFT TRUCK 4 Sheets-Sheet l Filed Sept. 9, 1942 r i w L in Wlllllllllllllll z i annum C. J Joh/'raeder- ATTORNEY v 'INVENTOR Jan. 9, 1945. c. s, scHRol-:DER 2,367,061

' LIFT TRUcK i v Filed Sept. 9, 1942 4 Sheets-Sheet 2 INVEN-TOR ATTORNEY Janf 9s4 c. s. scHRoEDER LIFT TRUCK Filed Sep1; 9 1942 4 Sheets sheet s INVEN'ToR Y u CASJC/Oeo/er- BY i MOM

ATTORNEY Jan. 9, 1945. c. sfscr-IKREbz-:IR

-LIFT TRcK Filed sept. 9, `1942 4 Sheets-,Sheet 4 ATTORNEY Patented Jan. 9, 1945 LIFT TRUCK Charles S, Schroeder, Philadelphia, Pa., assignor to The Yale & Towne Manufacturing Company, Stamford, Conn., a corporation-of Connecticut Application Septembei 9, 1942, Serial No. 457,729

26 Claims.

This invention relates to an industrial truck of the hand lift type, in which 'an elevating platform is elevated relatively to a lifting head through the operation of manuallyactuated lifting means.

My invention relates more particularly to a truck of the class in which mechanical rather than hydraulic lifting means are used to lift the elevating platform relatively to the lifting head. Even more particularly, my invention relates to a single frame truck in which the lifting head isfnot part of a wheel supported main' frame, but

is rather, a unit` adapted for assembly to the/ elevating4 platform through linkage mechanism. In this type of truck, the elevating platform is supported at its rear end by wheels pivoted to that rear end through links, means being provided so that the said links and the wheels thereon may be moved relatively to the eievating'platform as that elevating platform is lifted at its front endand relatively to the lifting head. While my invention is particularly adapted for application to a truck of this type, generally Yknown in the trade as the single. frame type,

those skilled in the art will fully appreciate that my invention may be applied to other types of trucks of the general glass described.

pawl, or the equivalent thereof, for maintaining the elevating platform in any andpreferably al1 of its elevated positions.

A further feature of my invention resides in the mounting of the holding member,v which is a holding pawl in its preferred form, on the lifting head. Even more particularly, this feature of my invention resides in the support means whereby the holding pawl is mounted so that it is readily An important feature of my invention resides particularly in the means whereby the elevating platform is lifted relatively to the liftinghead. More particularly, this feature of my invention f resides in the formation of one lof the links connecting the lifting head and the elevating platform so that it will4 have a series of spaced means that are engaged, preferably successively, by a lifting member on the lifting head.' Even more member that is mounted on the lifting head and is adaptedI to coact with spaced means on the same link that carries the spaced lifting means. More particularly, this featureofmy invention comprises the utilization of the ratchet teeth. or

the equivalent thereof, formed on the said` lifting link, as elements for cooperation with a holding moved by the lifting link itself out of holding position'when the support means are allowed to move away from supporting position.

As a further feature of my invention, the holdi.

ing pawl and its supporting means are controlled by a foot treadle, it being a further lfeature of this portion of my invention that the ydepression of the foot treadle allows the pawl and its sup-v porting means to be moved byv the weight -of the elevating platform out of holding position, and preferably with the lifting link itself moving the holding pawl out of holding relation to the ratchet teeth formed on the lifting head.

A further feature of my invention resides in the controlling of the lifting pawl so that it is moved out of operative contact with the lifting link prior to the release of the holding pawlfor its movement out of holding relation to the lifting link.

I have thus outlined rather broadly the more important features of my invention, in order that the detailed description thereof that follows may be better understood, and in order that my contribution to the art may be better appreciated. There are of course additional features of my inventionv that will be described hereinafter andother structures for carrying out the several pur.

poses of my invention. It is important therefore that the claims to be granted me shall be of suflicient breadth to prevent the appropriation of my invention by those rskilled in the art.

For a description of my invention, I shall refer now to the drawings wherein Fig. 1 is an elevation and partial section of a single frame lifting' truck in which my invention is installed. Fig. 2 is a vertical section through the front end of the truck of Fig. l illustrating the operating parts thereof. Fig. 3 is a view taken along lines 3-3 of Fig. 2. Fig. 4 is a view taken along lines 4-4 of Fig. 2. Figs, .5 and fi are views of portions of certain of casting that has al vertically extending standard I3 and a generally horizontal steering head support I4. Mounted for rotation on the steering head support I4 is what is termed generally in the art a steering head I5. This steering head I5 comprises a Vertical steering sleeve I5 and a bearing member I1 on which the lifting handle assembly is pivoted at I8 for vertical swinging movement relatively to the steering head. At the lower end of the steering sleeve I6 there is supported through the shaft I9aithe steering wheel I9. The steering wheel I9 is of course rotatable 4 on the axis of sleeve I9 by the lifting handle assembly 20.

This structure of the steering head an'd its mounting relatively to the lifting head is not part of the invention of this application and is old and well known in the art. It is merely necessary to know,for the purpose of understanding this invention, that the vertical swinging movement of the lifting handle assembly about the shaft I8 on the bearing member I1 is adapted to reciprocate a strut 2I for operatingthe lifting mechanism. For this "purpose, the strut 2l is formed with a ball '22 at its upper end, bearing in a socket .'23 ina lifting lever 24 pivoted about the f shaft 'on the standard I3 of the lifting head I 2.

On a shaft 26 mounted on the lifting head standard I3, there is pivoted a lifting link 21. This lifting link 21 is also pivoted about the shaft 28 t0 the vertical standard II of the elevating platform. Shaft 28 is carried onstandard II, `through the intermediary of the three spaced plates 29 that are welded to the standard I I. The lifting link 21 has a series of spaced lifting means thereon that take the form of ratchet teeth 30. It will be quite clear to those skilledin the art that'if `the lifting link 21 is rotated about its shaft 26 on the lifting head standard I3, it will effect a lifting movement of theelevating platform standard II through the shaft 28. This rotary lifting movement is imparted to the liftingV link 21 by means including the lifting lever 24 actuated by the strut 2|, all as will be described hereinafter.

The vertical lifting hea'd standard I3 extends downwardly and somewhat laterally to form a lower extension 35 relatively to which are formed ears 35. Lifting links 3,1, one at each side of the truck, are pivoted through a shaft 38 relatively to the ears 35 and therefore relatively to the ex-v tension 35 of the lifting head I2. These links are further pivoted through the shaft 39 relatively to downwardly extending lugs 48 of the elevating platform Ill, It will be noted best from Fig, 2, that a line drawn between the centers of

shafts

38 and 39 will be parallel to a line drawn through the centers of shafts 26 andv 28, and it is now obvious that as the elevating platform is lifted through the link 21 at the upper endof the lifting head standard I I relatively to the lifting head I2, the lower portion of the elevating platform will be similarly lifted on the links 31 relatively to the lifting head.

The rear end of the truck carries about a shafty 4I,`a pair of wheel supporting links 42 on which are mounted the rear wheels 43 of the elevating platform. The links 42 are pivoted at 44 to tension rods 45 that are pivoted at 45 to the links 31. It is quite obvious that during the lifting of the elevating platform from its full line position of Fig. 1 to its dash and dot line position, the tension rods 45 will pull the links 42 so as to rotate those links in a clockwise direction about the shaft 4I, thereby lowering the wheels 43 and lifting the rear endof the platform as the forward end thereof is lifted on the upper link 21 and the lower links 31. A

While I have described in rather considerable detail the mounting of the elevating platform relatively to the lifting head, it will be well to indicate that the .particular structure is that of a single frame truck and is per se, not new. My invention relates more particularly to the utilization of the usual elevating platform mounting means of a truck of the class described for eecting the lifting of the said elevating platform. For the particular purpose, this broad feature of my invention resides, in its preferred form, in the formation of the lifting link 21.

As heretofore set forth. this link 21 in its preferred form, has spaced lifting means in the form of ratchet teeth 30. -These ratchet teeth 30 are adapted for cooperation with a pawl that is pivoted at 5I on the lifting lever 24. A spring 55 is connected at to the lifting lever 24 and at 51 to the lifting'head whereby to maintain the lifting lever so that its socket 'portion 23 rests against the ball 22 of the strut 2|.` It is now obvious that downward swinging movement of the liftinghandle assembly 20 is adapted to re' ciprocate the liftinglever` 24 and thereby effect the movement of vthe pawl 50 to rotate the lifting link 21 through coaction with the ratchet teeth 30.

For controlling the operation of the lifting pawl 50 as will be hereinafter described, there is pivoted to that pawl at 58 a connecting rod 59 that is in turn. pivoted at 60 to a lever 8l, this lever 8| being mounted on the shaft 25 on which the lifting lever 24 is itself pivoted. A spring 82 is connected to the lever BI at 63 and to the lifting head at 51 and isadapted through the connecting rod 59 to maintain the lifting pawl 50 pressed against the ratchet teeth 30 as is clearly shown in Fig. 2.

For holding the elevating platform in any and preferably all of its elevated positions, I use what may be termed a holding pawl 55 pivoted on the shaft 88 relatively to a pair 'of support plates 81 that are mounted on the shaft 25 on which the lifting lever 24 is pivoted. A spring 58 is connected at one end tothe lifting pawl 55 and at its other end topin 39 on the said support plates 61. The support plates 81 have secured thereto on a short connecting shaft 10, a roller 1I that bears against the peripheral surface of a treadle cam 12. This treadle cam 12 is keyed at 13 to the shaft 14 to which is fixed the treadle 15 so that the movement ,of the treadle 15 effects the rotain Fig. 2, it will be noted that the lifting pawl 58 is maintained spring pressed against the teeth 38 of the lifting link 21. The holding pawl 85, is through the support plates 61 and the roller 1I maintained by the treadle cam 12 in holding relation to the teeth`30 of the lifting link 21. It will be noted that the weight o f the elevating platform will be transmitted from the teeth 88 to the holding pawl 65 along the lines extending between the shaft 5G and the shaft 25. It will,

therefore, be the shaft 25 that will support prac? tically all of the .weight of the elevating platform while but a small part of the weight will be transf `initted through the support plates 61 and tlfe roller 1l to the treadle cam 12, all as willl be fully appreciated.

With the parts in the position of Fig. 2, should the handle assembly 20 be swung downwardly. the lifting lever 24 will be moved from its full line position of Fig. 2 to its dash and dot line position, effecting a movement f the pawl 59 and a rotation of the link 21 about: the shaft 28 on lifting head standard i3. It is obvious that this ing movement of the lifting handle 20 will finally bring the parts into the position of Fig. 5, wherein the elevating platform is fully elevated and'is will effect a lifting of the elevating platform on the link 21 and lower links 81. Repeated swing- This lowering movement will be resisted by a dashpot 80 that'is supported at its lower end through a ball and socket joint on the lifting head, and is secured at its upper end on the shaft 28 relatively to the elevating platform. The construction, mounting and operation of the dashpot 80 are of a type well known in the art and do not per se form part of this invention.

As the elevating platform is lowered, it is very desirable that the parts be restored to their position of Fig. 2, so that the operator of the lifting truck will be able to effect a second lifting operation without performing any additional manual acts. For the particular purpose, the elevating platform is equipped with an vadjustable nut 82 that contacts a surface 83 forming an integral part of the treadle 15, so that as'the elevating platform moves from the position of Fig. 6 to the position of Fig. 2, the nut 82 will impinge against the surface 83 to rotate the treadle" 15 about the axis of the shaft 14. Once the treadle is rotated to a predetermined point by the nut 82, the spring 84 will complete therotation of the treadle to its normal position of Fig. 2, andthe holding pawl -65 and lifting pawl 50 will be restored to their operative position effective for the carrying out maintained elevated by the holding pawl 65. In

Fig. 5, the foot treadle 15 has been depressed to move lever and to bring the notch 18 of the treadle ycam 12- opposite the portion 19 of the lever 5|. The lever 6| andthe treadle 15 will cooperate to hold one another in this position against the pressure of the springs tending to return them to the position of Fig. 2. The said movement of the treadle cam 12 has, through the lever 6I and connecting rod 59, effected the withdrawal of the lifting pawl 50 from the teeth .30 0f the lifting link 21. This yields what is known in the art as a free handle. Thus, the handle assembly 20 may now move freely of the elevatthe roller 1l has merely rolled on the periphery -of the treadle cam 12 from the position of Fig. 2

to the position of Fig. 5. If, with the parts in.

the position of Fig. 5, it is desired to lower the load, the treadle is depressed to its position 0f Fig. 6, bringing the portion 12a of the periphery of the treadle cam 12 opposite the roller 1l. Since all support has now been withdrawn from the support plates 61, the lifting linkv 21 will,

through its ratchet teeth- 30, force the pawl, downwardly to the position of Fig. 6, and during this movement, the liftinglink will cooperate with the surface Sla of the holding pawl 881for camming the holding pawl out of holding relation to the teeth 30. In other words, as the position of the holding pawl and supportplates changes, the surface Gla contacts the lifting link 21 so as to be forced by that lifting link out of holding relation tothe ratchet teeth 30, all as is quite apparent from Fig. 6.

"I'he release of the holding pawl 65 -from the ratchet teeth 30 of link 21, will allow a complete -K lowering of' the .elevating platform back fromv the position if Fig. s to the position of Fig. '2.

of a new lifting and holding cycle. y

I believe that the operation and construction of my new and novel truck mechanism will now be quite apparent to those skilled in the art.

I now claim:

1. In a` truck of the class described, a wheel supported lifting head, an elevating platform wheel supported at its rear end, a lifting device pivoted directly to both the platform and the lifting head for coupling said lifting head and elevating platform, and spaced means on said lifting device whereby step by step movement is imparted thereto for moving the platform relatively to said lifting head.

2. In a' truck of the class described, a wheel supported lifting head, an elevating platform wheel supported at itsl rear end, a lifting device pivoted directly to both the platform and the lift'- ing head for coupling said lifting'head and elevating platform. spaced means on said lifting device whereby step by step movement is imparted thereto for moving the platform relatively to said lifting head, and lifting means on said lifting head cooperable with said spaced means for imparting said step by step movement to said lifting device.

3. In a truck of the class described, a wheel supported lifting head, an elevating "platform wheel supported at its rear end, a lifting device pivoted directly to both the platform and the liftysupported lifting head, an elevating platform wheel supported at its rear end, alink pivoted at one point to the front end of said platform and at another point to said lifting head for coupling said lifting head and elevating platform and whereby pivotal movement o f said link effects the lifting of the front end of said platform relatively t0 said lifting head, a series of liftingelements formed on said link, and lifting means on said lifting head adapted to engage said lifting elements Y successively whereby to lift said elevating platform.

5. In a truck of the classdescribed, a wheel supported lifting head, an elevating platform wheel'supported at its rear end, a link pivoted at one point to the front end of said platform and at another point te said lifting head for coupling said lifting head and elevating platform, the pivotal movement of said link effecting the lifting of said platform relatively to said lifting head, a series of ratchet teeth formed on said link, and a lifting pawl mounted for movement relatively to said lifting head and cooperable with ratchet teeth on said link to move said link whereby to lift said elevating platform.

6. In a truck of the class described, a wheel supported lifting head; an elevating platform wheel supported at its rear end, a link pivoted at one point to the forward end of said platform and at another point to said lifting head for coupling said lifting head and elevating platform, the

pivotal movement of said link effecting the lifti ing of said platform relatively to said lifting head, a series of ratchet teeth formed on said link, a

` lifting pawl mounted for movement relatively to said lifting head and cooperable with ratchet teeth on said link to move said link whereby to lift said elevating platform, and a holding pawl mounted on said lifting head and cooperable with ratchet teeth on said link to hold said platform in lifted positions.

7. In a truck of the class described, `a wheel supported lifting head, an elevating platform link, a lifting pawl mounted for movement relatively to said lifting head and cooperable with ratchet teeth on said link to move said link whereby to lift said elevating platform, a holding pawl mounted on said lifting head and cooperable with ratchet teeth on said link to hold said platform in lifted positions, a depressable treadle mounted on said lifting head, and means wherebyl the de` pression of said treadle releases said pawls successively from the ratchet teeth of said link.

8. In a truck of the class described, a lifting head, an elevating platform, a link pivoted at one point to said platform and at another point to said lifting head whereby pivotal movement of said link effects the lifting of said platform relatively to said lifting head, a series of ratchet teeth formed on said link, a lifting pawl mounted for movement relatively to said lifting head-and cooperable with ratchet teeth on said link to move said link whereby to lift said elevating platform,

. a holding pawl mounted on said lifting head and cooperable with ratchet teeth on said link to hold said platform in lifted positions,l a depressable treadle mounted on said lifting head, means whereby the depression of said .treadle from a first Mposition to a second position moves the lifting head, an elevating platform, a pivoted ratchet member for holding said elevating platform in any one of several elevated positions relatively to said lifting head, a'holding paw1 cooperable with the teeth of said ratchet member for holding said ratchet member and therefore said elevating platform in said several elevated positions, a support member for said pawl and on which said pawl is pivoted, a spring pressing said pawl towards the teeth of said ratchet, means pivotally mounting said support member on said lifting head, means holding said support member against pivotal movement on said mounting means away from a first position in which said pawl is pressed against the teeth of said ratchet member, said holding means being movable to release said support member for pivotal movement toward a second position with said holding pawl, and means whereby the said movement of said pawl and its support member withdraws the holding pawl from the teeth of said ratchet to allow lowering of said elevating platform from any elevated position.

l0. In a truck of the classdescribed, a lifting head, an elevating platform, a pivoted ratchet member for holding said elevating platform in any one of several elevated positions relatively to said lifting head, a holding pawl cooperable with theteeth of said ratchet member for holding said ratchet lmember and therefore said elevating platform in said several elevated positions, a support member for said pawl and on which said pawl is pivoted, a spring pressing said pawl l vsurface of said pawl engaged by said ratchet for moving the pawl away from said ratchet as said pawl and its support member moves toward said second position.

1l. In a truck of the class described, a lifting head, an elevating platform, a pivoted ratchet member for holding said elevating platform in any one of several'elevated positions relatively to said lifting head, a holding pawl cooperable with the teeth of said ratchet member for holding said ratchet member and therefore said elevating platform in said several elevated positions, a support member for said pawl and on which said pawl is pivoted, a spring pressing said pawl towards the teeth of said ratchet, means pivotally mounting said support member on said lifting head, a foot treadle for holding said support member against pivotal movement on said mounting means away from a first position in which said pawl is pressed against the teeth of said ratchet member, said foot treadle being movable to release said support member for pivotal movement towards a second vposition with said holding pawl, and a surface of said pawl engaged by said ratchet for moving the pawl away from said ratchet as said pawl-and its support member moves toward said second position.

l12. In a truck of the class described, a lifting head, an elevating platform, a pivoted ratchet member for holding said elevating platform in any one of several elevated positions relatively to said lifting head, a holding pawl cooperable with the teeth of said ratchet member for holding said ratchet member and therefore said elevating platform in said several elevated positions, a support member for said pawl and on which said pawl is pivoted, a spring pressing said pawl towards the teeth of said ratchet, means pivotally mounting said support member on said lifting head, a foot treadle for holding said support member against pivotal movement on said mounting means away from a first position in which said pawl is pressed against the teeth of said ratchet member, said foot treadle being movable to release said support member for pivotal movement towards `a second position with said holding pawl, a surface of said pawl engaged by said ratchet for moving the pawl away from said ratchet as said pawl and its support member moves toward said second position.

13. In a truck of the class described, a wheel supported lifting head, an elevating platform wheel supported at its .rear end, upper and lower links pivoted directly to integral portions of the front end of said elevating platform and said lifting head to form a complete truck and to mount said elevating platform for lifting movement relatively -to said lifting head, a movable lifting member mounted on said lifting head, and means formed on one of said links engaged by said lifting member for moving said link whereby to'lift the front en d of said platform relatively to said lifting head.'

14. In a truck of the class described, a wheel supported lifting head, an elevating platform wheel supported at its rear end, upper and lower connecting links pivoted at their opposite ends ing head, said means including a link pivoted at one end to an integral part of said platform and at its other end to an integral part of said lifting head, a movable lifting member mounted on said lifting head, and means formed on said link engaged by said movable lifting member for moving said link whereby to lift the front end of said platform relatively to said lifting head.

17. In a truck of the`class described, a wheel supported, lifting head, an elevating platform wheel supported at its rear end, means con-` necting the forward end of said platform to said lifting head to form a complete truck and to mount the forward end of said elevating platform for lifting movement relatively to said lifting head, said means including a connecting link pivoted at one end to an integral part of said platform and at its other end to an integral part of said lifting head, wheel supporting links pivformed on said connecting link and engaged by i said movable lifting member for repeatedly movdirectly to integral portions of the front endof said elevating platform and said lifting head to form a complete truck and to mount said elevating platform for lifting movement relatively to said lifting head, wheel supporting links pivoted to the rear end of said platform, means whereby ,the lifting movement of the front end of said ing said link whereby to lift the front end of said platform step by step relatively to said lifting head.

18. In a truck of the class described, a lifting I ment pivotally mountedon said lifting head, a.

treadle adapted to retain said support element in a predetermined position so long as saidk treadle is in a first position, and a holding pawl 15. In a truck of the class described, a lifting vthe forward end of said elevating platform for lifting movement relatively to said lifting head,

wheel supporting links pivoted to the rearend of said platform, means whereby thel lifting movement of the front end of said platform rela-` tively to saidlifting head moves said wheel suppivoted on said support element and cooperable with said ratchet teeth to hold said platform in its elevated positions so long as said support element is in its predetermined position.

19 In a truck of of the class described, a lifting head, an elevating platform, a link pivoted at one point to said platform and at another point to said lifting head, ratchet teeth formed on said link, a lifting pawl movably mounted on said main frame and cooperable with said ratchet teeth to rotatesaid link and lift said platform relatively to said lifting head, a support element pivotally mounted on said lifting head, a treadle adapted to retainv said support element in a predetermined position so long as said treadle is in a first position, and a holding pawl pivoted on porting links to lift the rear end of said platform,

a movable lifting member mounted on said lifting head, and means formed on said connecting link engaged by'said movable lifting member for moving said connecting link whereby to lift the front form for lifting movement relatively to said liftsaid support element and cooperable with said ratchet teeth to hold said platform in its elevated positions so`long as said support element is in its predetermined position, said treadle being rotatable to a second positiontoward which it is followed by said holding pawl and its support element, a surface of saidpawl then cooperating with said link to hold the pawl away from the ratchet teeth.

20. In a truck of the class described, a lifting head, an elevating platform, a link pivoted at one pointto said platform and at another point to said lifting head, ratchet teeth formed on said link, a lifting pawl movably mounted on said main frame and cooperable with said vratchet teeth to rotate said link and lift said platform relatively to. said lifting head, a support element with said link to hold the pawl away from the ratchet teeth, and means whereby said treadle moves said lifting pawl away from said ratchet teeth prior to moving to said second position.

- 21. In a truck of the class described, a lifting head, an elevating platform, a ratcheted link for lifting said platform relatively to said lifting head, a lifting pawl movably mounted on said lifting head and cooperable with said ratchet teeth to rotate said link and lift said platform relatively to said lifting head, a support element pivotally mounted on said lifting head, a treadle adapted to retain said support element in a predetermined position so long as said treadle is in a first position, a holding pawl pivoted on said support element and cooperable with said ratchet teeth to hold said platform in its elevated positions so long as said support element is in lts predetermined position, said treadle being rotatable to a second position toward which it is followed by said holding pawl and its support element, a surface of said pawl then cooperating with said link to hold the pawl away from the ratchet teeth.

22. In a truck of the class described, a lifting head, an 'elevating platform, a ratcheted link through whichsaldelevating platform is 'held in elevated position, a holding pawl, mounting means pivotally mounting said holding pawl relatively to' said lifting head for engagement with the ratchet teeth of said link to hold said platform in its elevated'positions, a treadle formed asl a Support for the mounting means of said holding pawl and movable from a support position for said mounting means to a release position relatively to said holding pawl and its mounting means, and a surface of said holding pawl cooperable with said link when said holding pawl moves on its mounting means to follow said treadle whereby to cam said holding pawl away from said ratchet teeth.

23. Ina truck of the class described, a wheel supported lifting head, an elevating 'platform wheelsupported at its rear end, a link pivoted at one point directly to the front end of said platform and at another point directly to said lifting head for coupling said lifting head and elevating platform and whereby pivotal movement of said link effects the lifting of the front end of said platform relatively to said lifting head, a series of lifting elements formed' on said link, lifting means movable on said lifting head adapted to movement and for rotating said steering head,

,and means whereby said steering handle actuates said lifting means in all steering positions of said steering head.

.24. In a truck of the class described. a wheel supported lifting head, an elevating platform wheel supported at its rear end, a link pivoted at one point to the front end of said platform and at another point to said lifting head for coupling said lifting head and elevating platform and whereby pivotal movement of said link effects the lifting of the front end of said platform relatively to said lifting head, a series of lifting elements formed on said link, lifting means on said lifting head adapted'to engage said lifting elements successively whereby to lift said elevating platform, a treadle movable from a first p0- sition to a second position for moving said lifting means from engaging relation to said lifting elements when said elevating platform is lifted, and means whereby the lowering of said elevating platform restores said treadle to said first position to release said lifting means for engagement with said lifting elements.

25. In a truck of the class described, a lifting head, an elevating platform, a link pivoted at one point to said platform and at another point to said lifting head whereby pivotal movement of said link effects the lifting of said platform relatively to said lifting head, a series of ratchet teeth formed on said link, a lifting p'awl mounted for movement relatively to said lifting headand cooperable with ratchet teeth on said link to move said link whereby to lift said elevating platform, means for holding said elevating platform in its lifted position, a depressable treadle mounted on said lifting head, means whereby the depression of said treadle from a rst'position to a second lposition moves the lifting pawl away from said ratchet teeth, means' whereby the depression of said treadle to a third position effects the move' ment of said holding means to release said elevating platform for lowering movement, and means on the elevating platform adapted te effect the movement of said treadle to its first position upon the lowering of said platform after the release movement of said holding means.

26. In a truck of the class described, a wheel supported lifting head, an elevating platform engage said lifting elements successively whereby to lift said elevating platform, a steering head rotatable on said lifting head, a steering handle ,pivoted on said steering head for verticall swinging wheel supported at its rear end, upper and lower ilinks pivoted directly tb integral portions of the front end of said elevating platform and said lifting'head to form a complete truck and to mount said'elevating platform for lifting movement relatively to said lifting head, a movable lifting member mounted on said lifting head, means formed on one of said links engaged by said lifting membersior moving said ,link whereby to lift the front endjpf said platform relatively to said lifting head, a steering head mounted on said lifting head, a steering handle pivoted for vertical swinging movement on said steering head and adapted to rotate said steering head, and means whereby lsaid steering handle actuates said lifting member in all steering positions of said steering head.

CHARLES S. SCHROEDER.