US2087861A - Lift truck - Google Patents

Description

Ju]y20,1937. & g. 2,087,861

LIFT TRUCK v Filedvoct. 4, 1 934 4 Sheets-Sheet l INVEINITOR BY W a. QUAYLE July 20, 1937;

LIFT TRUCK Filed Oct. 4, 1934 4 Sheets-Sheet 2 0m NM 0 mm on mm n AM flQ WM .ds. IHII L71 H.

lilli:

.n iii-265:? :IEEEEEE:

INVENTOR &

ATTORNEY July 20, 1937. e. QUAYLE LIFT rRucK Filed Oct. 4, 1954 4 Sheets-Sheet 3 INVENTOR A'I'I'ORNEY a. QUAYLE LIFT TRUCK July 20, 1937.

' 4 Sheets-Sheet 4 57 Filed Oct. 4, 1934 [N VENTOR A TTORNE Y Patented July 20, 1937 rear LIFT TRUCK Application Uctober 4, 1934, Serial No. 746,80?

2'7 Claims.

This invention relates to lifting trucks, and more especially to trucks of the hand lift typ This invention relates especially to a truck of the type adapted to be used in cooperation with the usual type of skid platform in which the load to be lifted is placed on the skid and is elevated when the platform of the truck is elevated.

It is usual, in the lift truck industry, for customers to purchase trucks having a lift exactly fixed in accordance with the skid platforms to be used therewith. Thus, anyone using skid platforms with 3 clearing will require a. truck, the initial position. of the platform of which is only 3" above the ground, the platform to be elevated any desired number of inches depending upon the terrain over which the truck is to traverse, and other conditions which may be present. If the customer uses skid platforms, spaced 6" from the ground, he will require a truck having an initial platform position of 6", with a lift such as may be required for the particular industry or terrain over which the truck is used.

From the truck manufacturers viewpoint, it

is extremely desirable to keep his truck models limited in number in order to facilitate production, and in order that he may sell at the lowest possible prices, and spread the utilization of trucks through industry. Naturally, he cannot do this if he is to supply different trucks for many different skids.

From; the users view point, a parallel problem arises. In some cases, customers having a variety of work, will require some platforms of 6" clearance, some of 8", some or various other in-between sizes. It is possible for them to pur chase several different sizes of trucks, or just a single truck which will have: an initial low platform and which will be capable of considerable lift to take care of the various types of platforms. Naturally, it is much cheaper and therefore, more desirable to purchase just a single truck capable of cooperation with differently sized skids. Where, in such cases, the load is sufficiently heavy to require a multiple lift truck in which a series of elevating strokes are necessary to give the proper lift of the platform, it will be readily seen that for very high clearance skids, a considerable amount of slow work must be done in order to get the truck platform to a position to accept the load and thereafter raise it fully. Since in the handling of loads, speed is required. and is mainly the reason for the purchase of trucks, it is obvious that the handling of loads underthe system just indicatedwill be extremely slow and will cut down considerably the speed in- (Cl. 254--lll) herently present in the usual lift truck in the handling of material.

With this problem in mind, I have developed a truck in which the: elevating platform is moved to an elevated position by a step by step op erating mechanism of the type shown in the the same time actuates the main lifting mech-- anism as though that mechanism. had been elevated by the main operating device instead of the auxiliary device. Thereafter, the main elevating mechanism will be operable to elevate the platform with the load. In effect, I provide a heavy duty lifting mechanism and a light duty lifting mechanism, the heavy duty lifting mechanism being adapted to elevate the platform after it has been elevated by the light duty mechanism sufiicientlyto pick up the load, thus avoiding the use of the heavy duty relatively slowly operating machinery until such time as it becomes necessary to use it.

Since my invention is especially adapted for an all purpose truck in which there must be a relatively high lift to take care of skid platforms of many sizes, it will be understood that the problem of elevating the platform is considerable. As in the prior art, I employ linkage mechanism between the platform and the main frame so that upon a pulling forward of the elevating platform,

there will be a lifting of that platform. It will be quite obvious that the lifting of the platform using such. relatively long links as are required for a high lift, would be extremely difficult and would impose a rather severe strain on the mechanism .and would require rather extreme effort on the part of the operator. I have, therefore, arranged a rather unique system of compound link mechanism. Whereas compound links have been utilized in the prior art in various ways, I utilize them in what I believe is an extremely novel manner, and therefore, I believe I have made a most valuable contribution.

I arrange to have my compound links so formed that the elevating platform is first moved integrally with one of the compound links using the other as a lifting link for movement relatively to the main frame. Thereafter, the platform moves relatively to both links, the two links acting as a unit. In operation, the platform moves integrally with the upper link relatively to the lower link, so that in effect, the upper link and the platform constitute a single platform during the first part of the elevating movement. The entire elevating movement of the platform is practically the same as though there were two I individual platforms, one lifted after the other.

For a better description of my invention in which the various features I have outlined above are more particularly described, and in which additional features which I believe are important contributions to the art are explained, I shall refer to the following drawings.

In those drawings, Fig. l is a perspective view showing my truck with the elevating platform in a lowered position. and with both the main and auxiliary lifting mechanisms in an initial position. Fig. 2 showsthe parts of Fig. 1 with the platform elevated by the auxiliary mechanism to the full extent of the lifting of that mechanism. Fig. 3 shows the parts of Fig. 2 with the main mechanism being utilized to complete the lifting operation.

Fig. 4: shows a side view of the parts of Fig. l with the elevating platform partially cut away to show the arrangement of the lifting links at the rear of the truck. Fig. 5 is a top view of the parts link of the the the lifting of Fig. i. Fig. 6 shows the operating auxiliary mechanism whereas Fig. 7 main lifting link which is carried by shaft.

Fig. 8 shows parts of my invention with the auxiliary lifting mechanism operated to the fullest extent of its movement. Fig. 9 illustrates the parts of Fig. 8 after lifting the main. lifting mechanism. Fig. 10 shows the relationship of several of the parts of the auxiliary and main lifting mechanisms. 11 is a detailed view of the front operating links connecting the main and elevating platforms. Fig. 12 is a View of parts of the auxiliary lifting mechanism. Figs. 13 and 14 are detail views of the elevating mechanism which per se forms no part of my invention and is fully described in the Stuebing Patent 1,785,368 referred to above. This mechanism does however form part of the combination I have devised.

Referring now more particularly to the drawings, reference numeral it indicates the main frame of a truck having an elevating platform ll equipped with a front saddle An elevating mechanism housing l3 is mounted at the front end'of main frame it and is braced relatively to the main frame by a bracing member i l. The truck has the usual front steering wheels iii and the rear load supper: 'lg wheels i5, the steering wheels being called by lifting housing it in the usual manner well known in this art and best set forth in the Stuebing patent referred to.

As indicated. generally, previously. the lifting mechanism in housing l3 acts to pull the elevatplatform ll forwardly relatively to the main frame 58, linkage mechanism be present be" tween the main frame and the elevating platform ii to contribute an upward movern nt of the platform ll It was also indicated previously that in order to obtain the full lift necessary, and to avoid strain on the lifting mechanism and the operator, a system of compound linkage mechanism was devised.

This linkage mechanism is best shown in Figs. 4, 8, 9, and 11. A lower link member 23 is pivoted at 2! to the main frame and at 22 to an upper link member 23 which in turn is pivoted to the platform ii at 24. Naturally, there will be two of these assemblies, one at each side of the truck, although only one will be refer ed to. At the front end of the truck, a lower link 25 is pivoted at 25 to the main frame and at 22' to an upper link 28 which is pivoted to the. platform i as at 29. There will also be one of these assemblies at each side of the front end of the truck. A lug 3!] is provided on the upper link 25 of the front upper link member 2. This lug 3t coacts with the surface 3! of the elevating platform so as to form a stop relation there-between and to prevent further leveling of the link in the initial position of Fig. 4.

A lug 32 is provided on each of the bottom links, this lug being cooperable with a horizontally extended arm 33 of each of the upper links. This relationship is provided to prevent clockwise rotation of the upper links relatively to the lower links about pivots 22 and 2'! during the first part of the lifting movement. This in turn prevents elevating movement of the platform about the upper links upon operation of the lifting mechanism. It will be readily appreciated that this would be a normal way for this linkage mechanism to react, due to the peculiar relation of the parts, and the relatively horizontal positions assumed by thepairs of link members.

The elevating action may now be described as follows. The elevating platform 5 l and its links will normally occupy the position shown in Figs.

1 and 4.. Upon forward pulling of the elevating platform ll by the lifting mechanism (to be described later) it will be quite obvious that the upper links 23 and 28 will be incapable of clockwise rotation'about the pivots 22 and 2'5, because of the lugs 32 carried by the lower links 25! and respectively. Therefore, theupper links 23 and 28 will move integrally with the platform II, and the platform and its upper links will act together as a single platform, in effect, pivoted at points 22 and 2? to the lower links 23] and 25.

Therefore, the elevating movement will be about the axes 2i and 26 of the lower links to the position illustrated in Figs. 2 and 8. In this position of the parts, it will be seen that the lever extensions 33 have become separated from the lugs 32. It will also be readily observed that additional lugs fi l carried by the upper links will have contacted lugs 35 carried by the lower link members and that the double links, through these lug members, have become, in effect, singlelinks connecting the elevating platform and'the main frame.

illustrated in Fig. 9 in which the elevating platform will continue to pivot around the pivots 2! and 26 but with the radius of movement being equal to the effective length of the links 29 and 23 at the rear, and 25 and 28 at the front of the truck.

It will bequite apparent that because of this particular arrangement of the mechanism, the lifting effort required during the first part of the elevating movement of the truck will be relatively light, because the movement will be aboutlthe lower pivots 2| and 26, with the effective radius of movement that of the lower links 23 and It will be further apparent that the remainder of the movement, when the platform ismore advantageously positioned for easy movement Thereafter, the movement will be from the position illustrated in Fig. 8 to the position will be about the front and rear links acting as a single link. In this way, the lifting effort required is approximately the same throughout the lifting operation, and an extremely high lift is relatively simple to obtain and the desirable resuits inherent in the apparatus are possible without extreme complication of the mechanism. 'While I will later describe various methods of the actual lifting mechanism enclosed within the casing I3 are best shown in Figs. 13 and 14' but will only be described briefly. The steering lever M3 is pivoted at II to an upward extending portion of the steering head 44 and has mounted thereon as at 42 a vertical member 43 which extends downward in the steering axis of the truck. The

' vertical member 43 will operate the lever member 46 through suitable connections 45-46% and which lever 46 will, through the pawl 41, actuate the ratchet 43.

The ratchet 48 is mounted for rotation with a shaft 49, splined to which are a pair of link members 58' which, through suitable connections to be indicated later on, operate to elevatethe platform I I. In order to prevent retrograde movement of the ratchet 48 as it is operated step by step by the pawl ll, a holding pawl 5| is utilized. This pawl is controlled by means of the pivoting control lever 52 which has a cam portion 53 for controlling the movement of lever .54 which carries the holding pawl 5|. It will be understood that the lever member 54 carrying the pawl 5| Will be moved in a counter-clockwise direction by its spring 54a when the cam member 53 is moved from cooperation with the stud member 55 on the lever 54. This movement of the lever 54 concentrically relatively to the ratchet 48 allows'for a full withdrawal of the holding pawl 5I At the same time, it will be appreciatedthat the cam portion 53 of the lever 52 will also abut the camming section 56 of the actuating pawl 41 so as to Withdraw that pawl also from cooperation with the ratchet. In thisv way a flying The member 52 is operated by the foot pedal 51 mounted on the outside of the housing I3. It is thought that the operation of this mechanism will now be quite clear even from this brief description, but should additional details be sought after, a review of the Stuebing specification will be fully explanatory.

Aswill be apparent from Fig. 5, there are two link members 50, one on each side of the actuating mechanism housing I3, each of these links elevate that platform by means of the actuating lever M3 and the pawl and ratchet mechanism contained in the housing Is. this lifting will be done against no load, there is really no necessity for applying" the rather slow action and the operation of the relatively heavy duty mechanism contained in the casing I3. Therefore, in order to speed up the operation of the'platform, in so far as its elevation to contact with a skid is concerned, I provide auxiliary mechanism which is best illustrated in Figs. 4 to 12 inclusive.

I mount at point 63 of the casing Is a lever 64 having a pedal 55 and pivoted at E6 to a further lever Iii. The lever 5? is in turn pivoted at 68 to a lever 69 mounted about the shaft 49 which supports, as will be recalled, the actuating links 50. This link member as is best illustrated in Fig. 6 and is shown as having an actuating lug I0 which in turn is adapted to cooperate with a lug II on one of the link members 58.

The relation of the parts will be quite clearly understood when it will be considered that the lever El is freely mounted about the shaft 49 to which both the ratchet member 58 and the link members 55? are integrally secured as by splining. Therefore, if the links 58 are operated from the position of Fig. 4, by movement of the operating lever it and the mechanism of casing I3, there would actually be no movement of the levers 64 and '69 and pedal of the auxiliary lifting mechanism.

However, should the truck in its position illustrated in Fig. 6 be placed under a skid platform so that a movement of three or four inches is required to bring the platform to the level of thelower surface of the skid, and should this movement be required to be quickly made, it will merely be necessary to step on the pedal 85. This will pull on the lever 6'1 and will actuate the lever 69 which, through lug Iii will strike the lug II on the link 59 at the left hand side of the truck, and Will move that link in the same manner as though it were actuated by the ratchet. Since this move ment will be relatively free because there is no load on the platform, a relatively light pressure on the pedal 2 5 will be suflicient. It will be understood also, that this will operate the ratchet 48 which, through the pawl 5i, will be retained against retrograde movement and so will retain the elevating platform in'any position to which it is lifted by the movement of the lever 64. Naturally the extent of movement possible by lever 64 is limited to that shown in Fig. 2 and is generally sufficient.

It will also be quite obvious that as soon. as pressure is taken off the pedal 65, the platform and its operating mechanism are retained in the particular position to which they may have been moved, and that further movement of the platform will be possible through the mechanism contained in housing I3, by the operation of lever 40 and the other means shown with relation thereto. In this way, it is possible for me to obtain a relatively fast movement of the elevating platform into contact with a skid, after which the heavy duty mechanism in the housing It may be utilized to obtain the final lifting action.

Because of the relatively high lift required by the elevating mechanism It I have changed Somewhat the mechanism of the Stuebing patent referred to by providing on each side of the truck a high lift link member it having a surface It which cooperates with the surface ii of the link member 50. Thus, preliminary movement of the linktll will bring the surfaces 16 and I1 together Furthermore, since r elevating means functionally as is illustrated best in Fig. 10. Thereafter, lifting through movement of the link 5E will be directly applied to the link ii! through pivots Eiia rather than through the linkage Bilo! as in the case of the preliminary lifting operation of the link 59. In this way, the movement toward the end of the operating action of the link 59 is faster than during the preliminary movement of the link 5%.

While I have thus described a form of my invention which I prefer and which I believe will best utilize its advantages, I believe that my contribution to this art is relatively broad, and I do not wish to be limited except as may be required by the state of the prior art. I now claim:

1. In a lift truck, a main frame and load supporting wheels, an elevating platform, links mounting said platform for lifting movement relatively to said main frame, elevating means for said platform especially adapted to elevate said platform when it is carrying a heavy load, means of connection between said elevating means and platform whereby said elevating means will elevate said platform, and auxiliary intermediate of said platform and elevating means cooperable directly with said means of connection to elevate said platform when it is carrying little or no load, said means of connection being operable to actuate the elevating means when themselves actuated by the auxiliary mechanism.

2. In a lift truck having a main frame and an elevating platform, heavy duty lifting means arranged to elevate said platform when it is heavily loaded, means of connection between said heavy duty lifting means and the platform whereby said means will elevate said platform. auxiliary elevating means functionally intermediate said platform and said heavy duty means, and means whereby said auxiliary elevating means are adapted to impart movement in a lifting direction to said means of connection to elevate said platform when it is carrying a light or no load, said auxiliary means being mounted so as to remain in any position in which they are positioned when said heavy duty lifting means are operated.

3. In a lift truck having a main frame and an elevating platform, heavy duty lifting means arranged to elevate said platform when it is in contact with a loaded skid, means of connection between said heavy duty lifting means and plat-- form whereby said means will elevate said platform, auxiliary lifting means functionally intermediate said platform and heavy duty means having a one way connection with said platform and adapted to elevate said platform until the loaded skid is encountered, said auxiliary means being mounted so as to remain in any position in which they are positioned when said heavy duty lifting means are operated.

4. In a lift truck having a main frameand an elevating platform, means for elevating said platform comprising a pawl and ratchet mechanism in which the pawl advances said ratchet step by step, means permanently connected between said ratchet and platform whereby the ratchet elevates said platform, means for operating said pawl, holding means for maintaining said platform in each of its partially elevated positions to prevent retrograde movement during backward movement of said actuating pawl, auxiliary means functionally intermediate the platform and said pawl and ratchet and adapted to elevate said platform into any one of a series of positions in which it will be held by said hold ng means, said elevating movement by said auxiliary means being adapted to actuate said ratchet through said permanent connection, said pawl and ratchet mechanism being operable thereafter to complete the elevating movement of said platform from any one of said series of positions.

5. In a lift truck having a main frame and an elevating platform, means for elevating said platform comprising a pawl and ratchet mechanism in which the pawl advances said ratchet step by step, the ratchet having means operated thereby to elevate said platform, means for operating said pawl, holding means for maintaining said platform in each of its partially elevated positions to prevent retrograde movement during backward movement of said actuating pawl, auxiliary means adapted to elevate said platform into any one of a series of positions in which it will be held by said holding means and comprising a foot treadle, a lever pivotally connected to said foot treadle and in turn connected to said platform to elevate the same, means whereby said liftin movement by said auxiliary means actuates said first elevating means in the same manner as though they had been operated to accomplish said elevation, after which said first elevating means may finish the elevating movement of said platform.

6. In a lift truck, a main frame, an elevating platform, means mounting said platform for lifting movement relatively to said main frame, a heavy duty lifting means for lifting said platform relatively to said main frame, means of connection between said heavy duty lifting means and said platform whereby said platform is lifted,

an auxiliary lifting mechanism functionally intermediate said platform and said heavy duty means, means whereby said. auxiliary mechanism lifts said platform, said means of connection between said platform and heavy duty lifting means operating to actuate said heavy duty means as said platform is lifted by said auxiliary means whereby said heavy duty means may at any time assume the lifting of said platform.

'7. In a lift truck having a main frame and an elevating platform, a step by step platform elevating mechanism, means of connection between said step by step mechanism and said platform whereby operation of said step by step mechanism elevates said platform, means for holding said platform at each individual raised step, auxiliary means functionally intermediate said platform and said step by step mechanism adapted to elevate said platform into any one of said step positions in which it will be held by said holding means, said lifting movement of the platform by said auxiliary mechanism being operative through said means of connection to actuate said step by step mechanism in the same manner as though said step by step mechanism had been operated to accomplish said platform elevating movement, after which said step by step mechanism may finish the elevating movement of said platform.

8. In a lift truck having a main frame and an elevating platform, means for elevating said platform comprising heavy duty means requiring lengthy operation and having a relatively high mechanical advantage, auxiliary means functionally intermediate said platform and heavy duty means adapted to elevate said platform until it comes into contact with a loaded skid but having less mechanical advantage than is required to fully elevate said platform when loaded, means of connection between the plat- 60 3 ratchet and platform and engageable with said form and said heavy duty means whereby lifting of said platform by said functionally intermediate auxiliary means actuates the said heavy duty lifting means in the same manner as though said. heavy duty means had been operated to accomplish said elevation, after which said heavy duty means may finish the elevating movement of said platform. 7

9. In a lift truck having a main frame and an elevating platform, means for elevating said platform comprising heavy duty means requiring lengthy operation and having a relatively high mechanical advantage, auxiliary means. functionally intermediate said platform and heavy duty means comprising a leverage system having considerable mechanical advantage and adapted to elevate said platform until it comes into contact with a loaded skid but having less mechanical advantage than is required to fully elevate said platform when loaded, and means of connection between said platform and said heavy duty lifting means whereby said heavy duty means may finish the elevation of said platform from any position to which it is raised by said auxiliary means.

10. In a lifting truck having a main frame and I an elevating platform movable upwardly relatively thereto, a step by step elevating mechanism comprising a ratchet and a pawl operable to rotate said ratchet, a second pawl for preventing retrograde movement of said ratchet, link members operatively interconnected with said platform and said ratchet for elevating said platform as said ratchet is advanced step by step,

said second pawl serving to hold said platform in -each step, an auxiliary lifting device functionally intermediate said platform and pawl and ratchet, said auxiliary device being cooperable with said link members for elevating said platform until a load is encountered thereby, said platform movement being arranged to actuate said ratchet through said interconnecting link members in the same manner as though said ratchet has been advanced by its pawl, said pawl being operable to advance said ratchet from any lifting of said platform by said auxiliary device.

11. In an elevating truck having a main frame and an elevating platform, a lifting ratchet, link mechanism for elevating said platform and movable in a platform elevating direction upon rotation of said ratchet in one direction, and in a platform lowering direction upon rotation of said ratchet in a reverse direction, a lifting pawl adapted to actuate said ratchet step by step in an elevating direction, means for locking said platform against retrograde movement in each step, auxiliary elevating mechanism for said platform functionally intermediate said lifting link mechanism for elevating said platform, said ratchet being advanced relatively to its pawl by said platform when elevated by said auxiliary mechanism throughthe said link mechanism between the ratchet and platform, said pawl being thenoperable to rotate the ratchet in an elevating direction when the auxiliary elevating movement ceases to operate the link mechanism further to elevate said platform.

12. In a truck having a main frame and an elevating platform, an elevating link pivoted to the main frame, a second link pivoted to the platform and to the first link, means for actuating said platform so that it may be elevated through the intermediary of said links, means whereby said platform is first movable integrally with the second link and about the main frame pivot of said first link while pivoting also about the pivot joining said links, and means whereby said platform thereafter pivots relatively to both of said links and about the axis of said main frame pivot.

13. In a truck having a main frame and an elevating platform, an elevating link pivoted to the main frame, a second link pivoted to the iatform and to the first link, means for actuatsaid platform so that it may be elevated through the intermediary of said links, means preventing pivotal movement of said second link relatively to said first link in a lifting direction whereby said platform is first movable integrally with the second link and about the main frame pivot of first link while pivoting also about the pivot joining said links, said platform being then adapted to pivot relatively to both of said links and about the axis of said main frame pivot.

14. In a truck having a main frame and an elevating platform, an elevating link pivoted to the main frame, a second link pivoted to the platform and to the first link, means for actuating said platform so that it may be elevated through the intermediary of said links, means preventing pivotal movement in a lifting direction of said second link relatively to said first link whereby said platform is first movable with the second link and about the main frame pivot of said first link while pivoting about the pivot joining said links, means arranged to join said links for integral movement after a moderate elevating movement of the platform, whereby said platform may thereafter be elevated relatively to said links as an integral unit and about the axis of said main frame pivot.

15. In an elevating truck of the type having a mainframe and an elevating platform linked thereto for forward and upward movement, that improvement which comprises substituting a pair of links for the usual single link, one of said pair being pivoted to the main frame, the second of said pair being pivoted to the elevating frame and to said first link, said links being arranged to take a fairly horizontal position when the elevating platform is lowered so as to present a fairly straight line toggle against the pulling forward of said platform, whereby the pulling forward of said platform will tend to move it relatively to the second link about the axis of the pivot joining said links, means adapted to prevent such movement whereby said platform is first movable integrally with the second link and about the main frame pivot of said first link while pivoting also about the pivot joining said links, said platform being then adapted to pivot relatively to both of said links and about the axis of said main frame pivot.

16. In an elevating truck of the type having a main frame and an elevating platform linked thereto for forward and upward movement, that improvement which comprises substituting a pair of links for the usual single link, one of said pair being pivoted to the main frame, the second of said pair being pivoted to the elevating frame and to said first link, said links being arranged to take a fairly horizontal position when the elevating platform is lowered so as to present a fairly straight line toggle against the pulling forward of said platform, whereby the pulling forward of said platform will tend to move it relatively to the second link about the axis of the pivot joining said links, means preventing pivoted movement in a lifting direction of said second link relatively to said first link whereby said platform is first movable integrally with the second link and about the main frame pivot of said first link while pivoting also about the pivot joining said links, said platform being then adapted to pivot relatively to both of said links and about the axis of said main frame pivot.

17. In an elevating truck of the type having a main frame and an elevating platform linked thereto for forward and upward movement, that improvement which comprises substituting a pair of links for the usual single link, one of said pair being pivoted to the main frame, the second of said pair being pivoted to the elevating frame and to said first link, said links being arranged to take a fairly horizontal position when the elevating platform is lowered so as to present a fairly straight line toggle against the pulling forward of said platform, whereby the pulling forward of said platform will tend to move it relatively to the second link about the axis of the pivot joining said links, means preventing pivotal movement of said second link relatively to said first link whereby said platform is first movable with the second link and about the main frame pivot of said first link while pivoting about the pivot joining said links, means arranged to join said links for integral movement after a moderate elevating movement of the platform, whereby said platform may thereafter be elevated relatively to said links as an integral unit and about the axis of said main frame pivot.

18. In a lifting truck, an elevating platform, a lifting lever, a member rotatable by said lever and adapted to elevate said platform, a link rotatable with said member, an intermediate link pivoted to said first link, a platform link pivoted to said intermediate link, rotation of said first link being effective to pull said platform link through said intermediate link, and means whereby said intermediate link and said first link move as a single unit to actuate said platform link after a partial movement of said first link.

19. In a truck, a main frame, an elevating frame mounted on said main frame, a lifting head, step by step lifting mechanism on said head, a lifting link operated by said step by step lifting mechanism and connected to said elevating frame to impart lifting movement to said elevating frame, a foot treadle member carried by said head, a lever having a one way operating connection with said link and operable by said foot treadle member to elevate said platform directly, said foot treadle member and its lever being adapted because of said one Way operating connection to remain in any position they may be placed when said step by step mechanism operates to elevate said frame.

20. In a lifting truck having a main frame and an elevating platform, means mounting said elevating platform for elevating movement relatively to said main frame, said means comprising compound links allowing for elevation of said platform through the application of relatively slight lifting force to said platform during the first part of the lifting movement, and relatively great lifting force during the latter part of the lifting movement, lifting means especially adapted to elevate said platform through the latter part of the lifting movement, and auxiliary lifting means adapted to elevate said platform during the first part of its lifting movement.

21. In a lifting truck having a main frame and an elevating platform, means mounting said elevating platform for elevating movement relatively to said main frame, said means comprising compound links allowing for elevation of said platform through the application of relatively slight lifting force to said platform during the first part of the lifting movement, and relatively great lifting force during the latter part of the lifting movement, lifting means especially adapted to elevate said platform through said latter part of the lifting movement, and auxiliary lifting means adapted to elevate said platform during the first part of its lifting movement, said first lifting means being constructed so as to lift the platform through its entire lifting movement if desired.

22. In a lifting truck having a main frame and an elevating platform, means mounting said elevating platform for elevating movement relatively to said main frame, said means comprising compound links allowing for elevation of said platform through the application of relatively slight lifting force to said platform during the first part of the lifting movement, and relatively great lifting force during the latter part of the lifting movement, pawl and ratchet lifting means especially adapted to elevate said platform through said latter part of the lifting movement, and auxiliary lifting means adapted to elevate said platform during the first part of its lifting movement independently of said pawl and ratchet, said pawl and ratchet lifting means being connected with said platform so as to lift the platform through its entire lifting movement if desired.

23. In a truck, a main frame, an elevating frame mounted on said main frame, a lifting head, step by step lifting mechanism on said head, a lifting link operated by said step by step lifting mechanism and connected to said elevating frame to impart lifting movement to said elevating frame, a foot treadle member carried by said head, a lever having an operating connection with said link and operable by said foot treadle member to elevate said frame directly, and means whereby said frame is held in said elevated position through its connection with said step by step mechanism.

24. In a truck, a main frame, an elevating frame mounted on said main frame, a lifting head, step by step lifting mechanism on said head,

leans connecting said step by step lifting mechanism to said elevating frame and adapted to impart lifting movement to said elevating frame, a foot treadle member, means operable by said foot treadle member to elevate said frame directly, and means whereby said frame is held in said elevated position through its connection with said step. by step mechanism.

25. In a lift truck, a main frame, an elevating frame mounted on said main frame, a lifting head, heavy duty lifting mechanism on said head, means connecting said heavy duty lifting mechanism to said elevating frame'and adapted to impart lifting movement to said elevating frame, a foot treadle member, means operable by said foot treadle member to elevate said frame directly, and means whereby said frame is held in said elevated position through its connection with said heavy duty mechanism.

26. In a lift truck, a main frame, an elevating platform, links mounting said platform for forward and upward movement relatively to said main frame, a heavy duty lifting mechanism for said main frame for pulling it forwardly and up- Wardly by means of its links, a connecting member between said platform and said heavy duty lifting mechanism through which said heavy duty lifting mechanism pulls said platform forwardly and upwardly, an auxiliary lifting mechanism functionally intermediate said platform and heavy duty lifting mechanism, and means whereby operation of said auxiliary mechanism elevates said platform and through the said means of con- 10 nection causes the lifting movement of the platform to operate the said heavy duty mechanism.

27. In a lift truck having a main frame and an elevating platform, heavy duty lifting means arranged to elevate said platform when it is in contact with a loaded skid, means of connection between said heavy duty lifting means and platform whereby said means will elevate said platform, While reversely, elevating movement of said platform will operate said heavy duty means, auxiliary lifting means functionally intermediate said plat form and heavy duty means cooperable with said platform and adapted to elevate said platform until a loaded skid is encountered, the said means of connection between said platform and heavy duty lifting means being actuated by the lifting movement of the platform by the auxiliary means to operate the said heavy duty mechanism.

GEORGE QUAYLE.

Images