US2217704A

US2217704A - Hand lift truck

Info

Publication number: US2217704A
Application number: US274659A
Authority: US
Inventors: Quayle George
Original assignee: Yale and Towne Manufacturing Co
Current assignee: Yale and Towne Manufacturing Co
Priority date: 1939-05-19
Filing date: 1939-05-19
Publication date: 1940-10-15
Anticipated expiration: 1957-10-15

Description

Oct. 15, 1940. G. QUAYLE HAND LIFT TRUCK Filed May 19, 1939 6 Sheets-Sheet 1 INVENTOR ATTORNEY 0a. 15, 1940. a LE 2,217,704

HAND LIFT TRUCK I I EVEN-r0 BYW 'l ATTQRNE? Oct. 15, 1940. G. QUAYLE 2,217,704

.mmn LIFT TRUQK .Filed m 19, 19:59 6 sheets-sheet 5 INVENTOR BY y a Wm ATTORNEY- Oct. 15, 1940. QUAYLE 2,217,704

HAND LIFT TRUCK.

Filed May 19, 1939 6 Sheets-Sheet. 4

v I ATTORNEY Oct. 15,

cs. QUAYLE HAND LIFT TRUCK Filed May 19, 1939 6 Sheets-Sheet 5 ATTORNEY Oct. 15, 1940. G, Y E' 2,217,704

HAND LIFT TRUCK Filed May 19, 1939 6 Sheets-Sheet 6 INVENTOR ATTORNEY Patented Oct. 15, 1940 UNITED STATES PATENT OFFICE HAND LIFT TRUCK Application May 19, 1939, Serial No. 274,659

28 Claims.

This invention relates to a lift truck of the type in which an elevating platform is elevated relatively to a main frame through actuation of a hand operated lifting mechanism.

More particularly, my invention relates to a truck in which the lifting mechanism is of the multi-stroke type; that is, in which the lifting handle through a series of swinging movements,

elevates the load platform. Trucks of the type to m which this invention is directed are, of course,

well known in the art. The truck of my invention contributes to the art certain features of operation and construction which are of exceeding merit, and which I shall first describe generally and then more specifically.

In the truck of my invention, the lifting mechanism comprises a pivoting member operated by the lifting handle of the truck, the pivoting member being carried by the elevating platform. In the preferred embodiment of my invention, this pivoting member takes the form of a ratchet, and it is locked by a pawl relatively to the lifting platform when the pawl is in one position. When actuated thereafter by the lifting handle, it does not pivot relatively to the platform, and therefore the swinging movement of the lifting handle imparts lifting movement to the elevating platform.

Preferably, the means of connection between the lifting handle and the reciprocating ratchet are such that the lifting handle may operate the ratchet in any steering position, so that the lifting handle may function as the steering memberfor the truck. The means of connection between the lifting handle and the reciprocating ratchet are in themselves novel and form a distinct contribution to the art. For holding the elevating platform in any elevated position, I employ holding mechanism which is biased by the weight of .the elevating platform out of holding position. The control means for this holding mechanism maintains" the holding mechanism against movement by the weight of the platform out of holding position. When the control means are moved into release position, the weight of the platform contributes to the movement of the holding mechanism out of holding position in a most novel manner.

In the preferred form of my invention, the holding mechanism takes the form of a toggle which is biased towards collapse, and which is held against collapse by certain control mechanism. My holding mechanism forms an improvement over the holding mechanism which is disclosed in the Stuebing Patent No. 1,785,368, which patent is owned by The Yale & Towne Manufacturing Company, the owner of this application.

The control for the lifting mechanism whereby the lifting handle may be released for free movement, and the control of the holding mechanism, 5 are interrelated. The purpose of this interrelation is to free the lifting handle relatively to the lifting mechanism prior to the release of the holding mechanism, so as to avoid a flying handle. The means whereby I obtain this result are novel and form an improvement over the means disclosed by Stuebing in the patent mentioned above.

As a further feature of my invention, I arrange to connect my lifting handle to the lifting mechanism automatically upon the movement of the lifting platform to its lowered position. Because of this construction, no operation of the control mechanism is required as in prior art trucks, as a prerequisite to the operation of the lifting mechanism. In this way, I eliminate an operation required in prior art trucks; and make it possible for my truck to complete a lifting and lowering cycle in less time than prior art trucks. As a further feature, the lowering of the platform resets also the holding mechanism so that it is in a position thereafter to hold the elevating platform as it is lifted by the movement of the lifting handle.

Still a further feature of the construction is the mounting of the lifting and holding mechanism and the mechanism which checks the lowering movement of the elevating platform, all in very compact relationship, and preferably within a casing, so that a compact and eflicient streamline design is obtained.

The features of my truck thus generally described are probably the most important thereof, but other desirable constructions and combinations will appear as I describe my invention in greater detail, and will be claimed as part of my monopoly. Thoseskilled in the art will readily appreciate that the various features of my invention may be obtained through many different physical embodiments, and I therefore expect to secure for myself a monopoly sufficiently broad to prevent the utilization of my contribution by othersin, such different physical embodiments.

Referring now more particularly to the drawings, Fig. l is an elevation of my lift truck, while Fig; 2 is a view looking downwardly thereon. certain parts of the rear end being shown in section. Fig. 3 is a partial section and elevation through 16 front/end of the truck showing the various parts at the beginning of the lifting operation, and before any lifting has been done. Fig. 4 is a section of Fig. 3 taken along lines 4-4 of Fig. 3. Fig. 5 is a view similar to Fig. 3, but showing the elevating platform lifted somewhat from its position of Fig. 3. Fig. 6 shows the parts of Fig. 5, but with the lifting mechanism positioned so that the lifting handle is free for swinging movement without actuating the lifting mechanism. Fig. '7 is a view of certain parts of Fig. 6 showing the holding mechanism released so that the elevating platform may be lowered. Fig. 8 shows the resetting of the holding pawl upon the lowering movement of the lifting platform, with the lifting pawl of the lifting mechanism about to be reset.

Refen-ing now more particularly to the drawings, and especially Figs. 1 and 2, I shall first describe my truck generally. The main frame is designated by reference numeral l0, while the elevating platform is designated by reference numeral ll. At the front end of the elevating platform there is a casing l2 in which is mounted the lifting mechanism and also the holding mechanism. Within the casing i2, there is also mounted a vertical check or dashpot II, which is best shown in Fig. 4, and which is connected at one end to the "shaft l4 of easing l2, and at its other end to the main frame at point I. The check i8 is preferably of the hydraulic type well known in this art, and cushions the elevating platform as it moves downwardly after being released, all as is understood by those familiar with the art.

The front end of the main frame carries a steering head it which includes a pair of steering wheels i1, and a lifting and steering member ll to which is fixed the lifting and steering handle IS. The construction of the steering head will be described in more detail later in the specification.

The rear end of the truck is supported by a pair of wheels l'la mounted on an axle "b, as is standard in this art. The main frame ll extends beyond the axle l'lb, and supports upon this extension a. shaft 20, which supports through b ings 2|, the rear lifting links 22. The links 22 are in turn connmted by a reinforcing tube 220. Welded to the links 22 is a shaft 22 which is. mounted relatively to the elevating platform II in bearings 24. The construction of this rear end will not be described in more detail here, nor will the purpose of this construction be indicated, since this construction will be made the subject of a separate patent application.

The forward end of the elevating platform Ii is supported in a conventional manner by forward links 25. It will be understood by those skilled in the art that upon operation of the handle is, the lifting and steering member is will be actuated, operating the lifting mechanism within the casing i2 in a manner to be described later, whereby to lift the elevating platform on said forward links 25 and rear links 22 relatively to the main frame.

Now that I have described thus generally my truck, I shall refer to Figs. 3 and 5 for a description of my steering head Ii. The steering head I! may, of course, be of any conventional type,- but in my preferred construction, it includes a sleeve 2'0 which carries the front axle 25 on which are mounted the front steering wheels ll.

Suitable thrust bearings

21, 28, 22 accept the various loads of the steering head so that the steering head may be free to rotate and thereby swivel the wheels II. The upper end of the steering head It supports a shaft 30 on which is mounted for pivoting movement the lifting and steering member II, to which, as has already been indicated, is secured the lifting and steering handle ll. 5

Formed integrally with the steering head I8 are a pair of ears 2|, to which is pivotally secured a bar 32 which carries on a pin 23 a roller 24 mounted for movement within the hollow handle I9. Extending upwardly from the pin 33 is a guide bar 35, about which is mounted a spring 36. The spring 38 operates between a disk 21 on the guide bar 26 and a pin 38 fixed to the upper part of the handle. It will be readily appreciated that it is the function of the spring 36 to press the handle upwardly into its position of Fig. 3, thus compensating for the weight of the handle. The spring is compressed as the roller it enters the handle when the handle swings downwardly, so as to be effective to swing the handle upwardly when it is released. This feature is called a balanced handle, and its construction is covered broadly in a copending application.

In the position of the handle of Fig. 3, the '25 surface 29 of the member I. is adapted to rest against the surface 4| of the steering head ll, thus limiting the upward movement of the handle II by balancing spring 26. In this position of the handle, it is readily seen that the 30 truck may be pushed by application of force to the handle, with the forces accepted by the two surfaces is and 60. It will, of course, be appreciated that steering movement is imparted to the steering wheels I! by the handle it through the member ll, the shaft II. and the sleeve portion 28a. of the steering head.

For operating the lifting mechanism, the member I8 is equipp d with a pin 4i to which is secured a vertical lifting strut 42, as is best shown 40 in Fig. 3. The upper end of the strut 42 enters partially into a bore within a shaft 43, and is thus adapted for rotation in its own axis relatively to the said shaft 43. The shaft 42 is in turn mounted for rotation on a horizontal axis 45 within the cars 44 of what I term a lifting ratchet 4i.

A threaded adjusting pin 40 is threaded within a block 41 mounted for rotation with the shaft 42, and extends downwardly into the bore in which lies the upper end of strut 42. The block 41 is also traversed by the upper end of the strut 42, as is shown. Through this construction, pin 4! bears against the upper end of strut 42 for accepting the thrust of the strut 42 as the strut moves upwardly. A further function of the ad justing pin 46 is to follow the downward movement of the lifting strut 42, as the lifting ratchet 4! moves downwardly with the said strut 42. By rotating the pin. 46. any play between it and so the strut 42 is eliminated.

The lifting ratchet 45 is mounted for rotation about the shaft H, which is the same shaft to which is secured one end of the hydraulic check previously described by me. For controlling the rotation of the lifting ratchet 45 about the shaft [4, I utilize what I term a lifting pawl 48 which cooperates with the teeth 42 of the lifting ratchet 4i. The lifting pawl 48 is supported on a shaft I secured to the casing l2 through' an internal bearing ear Ii formed within the casing, as is shown in Fig. 4, and through a further bearing on the outer shell of the casing.

Mounted about this same shaft 50 is what I term a pawl carrier I2 which is U-shaped in cross section. and which supports through a shaft 53 the holding pawl l4. Shaft I! will be termed by me a control shaft, for reasons which will be apparent later. The holding pawl cooperates with a holding ratchet II which bears against the main frame at 8', and through its said bearing at 58 is capable of considerable necessary movement. The ratchet I! is maintained against its bearing 56 by the spring 51, all as is quite apparent from a view of Fig. 3. It will be noted that the ratchet 55 is supported relatively to the casing if of the lifting platform by the shaft 58, so that as the lifting platform and the casing I! move upwardly to the position of Fig.- 5 from the position of Fig. 3, the ratchet Bl will remain properly supported. The bearing 58 allows for such changes of position of the ratchet 56 as take place during its movement from Fig. 3 to Fig. 5.

Preferably, a single spring I! is connected. at 60 to the lifting pawl II, and at II to the holding pawl 54, and urges the lifting pawl 48 against the lifting ratchet l5, while simultaneously pressing the teeth 62 of the holding pawl 54 against the teeth 63 of the holding ratchet I5.

A further fimction of the spring" is to ten to break the toggle, in effect, formed by the pawl carrier 52 and holding pawl I4, between the following points; the point where the pawl teeth 62 engage the teeth 63 of the holding ratchet 55, the control shaft 53, and the pivot shaft III. This tendency to break the toggle, in effect, is resisted by control mechanism designated generally by reference numeral 04. This control mechanism 64 is in the form of a three-armed cam splined to a shaft 85, to which shaft is secured. also as by splining, or in any other suitable way, the control pedal 88.

One arm of the control mechanism '4 is pinned at 61 to the rod 68 to which is fixed a disk 69. A spring 10 is mounted about the rod 6., with its lower end against disk 89. Spring I. bears at its upper end against a collar ll mounted on rod Ill and which is secured through pins 12 to ears extending from lifting ratchet 45. It will be seen that the spring II will tend, through the collar H, to rotate the lifting-ratchet 45 in a clockwise direction so as to bring the adjusting screw it against the upper end of the vertical lifting strut 42, as was previously described, thus taking up any play in the lifting mechanism and assisting the balancing spring 3' to maintain the lifting handle in its vertical position of Fig. 3. Spring 10 causes ratchet ll to follow the non-lifting movement of strut 42. At its other end, the spring 10 tends to rotate the control mechanism 64 in a counter clockwise direction about the axis of shaft 65.

In the position of the parts in Fig. 3, it will of A course be noted that a second arm of the control mechanism 64, designated by reference numeral 13, has a cam surface 14 against which presses a control roller 15 secured about the control shaft 53. In this position of the parts, the collapse of the toggle previously described is prevented. and the holding pawl I may be maintained by the spring 59 with its teeth 8! ready to engage the teeth 63 of ratchet It as soon as the elevatin platform is lifted a slight amount.

With the parts in the position of Fig. 3, a downward swinging movement of the handle it 'will impart vertical movement to the lifting strut 52, which will tend to rotate the lifting ratchet 45 in a counter clockwise direction. This tendency of the lifting ratchet u to rotate will, of

course, be prevented by the lifting pawl 48, which looks the ratchet against any clockwise rotation relatively to the elevating platform. Therefore.

a vertical swinging movement of the handle it will lift the ratchet 45 and the casing i2, and therefore, the elevating platform, from theposition of Fig. 3 to "the position of Fig. 5. Thereafter, a return of the lifting handle from a downward position to the vertical position of Fig. 5 will be possible, because the teeth 49 of ratchet 45 will simply ratchet past the teeth of the pawl 48, the cooperating teeth of the pawl and ratchet being designed for this purpose. This ratcheting movement is allowed, of course, by the spring 59, which is simply extended, as is understood by those skilled in the art. From the position of Fig. 5, the elevating platform may be further lifted by a second downward swinging movement of the handle it, just as has already been described.

that the lifting parts are all in practically the samerelation as in Fig. 3, except that the pawl 8 is now in contact with different teeth of the lifting ratchet 49, while the teeth 62 of the holding pawl 54 are in contact with holding teeth 63 of the ratchet 55. It will be noted, furthermore, that the point of contact between the teeth 62 of pawl 54 and the teeth 63 of ratchet i5 is so related to the control shaft II and the shaft 50 upon which is mounted the pawl carrier I2. that the toggle, in effect, formed by the pawl BI and the pawl carrier 52 has a tendency to be broken, or to be collapsed by the weight of the load platform itself, Just as previously described. This tendency to break is, of course, opposed by the cam surface it on the control arm ll of the control mechanism 84, against which bears the roller 15 of control shaft 53.

If, in the position of the parts in Fig. 5, it is decided that the platform has been sufficiently elevated, the operator may release the lifting handle I9 from the lifting mechanism, so that he may pull the truck away by the swinging of the lifting handle I! down to its positon of Fig. 6, in which position the truck may be more easily pulled. In order that this may be done, the control mechanism has a further lever arm 16 adapted to contact a downwardly extending arm I1 of the lifting pawl 48. When the operator of the truck steps on the treadle N, the shaft 85 will rotate control mechanism 64 clockwise from the position of Fig. 5 to the position. of Fig.6, bringing -the arm 16 against the arm l1. and thus moving the lifting pawl ll away from engagement with the lifting ratchet 45. as is best shown in Fig. 6.

This movement naturally compresses further the spring "operating between the control mechanism N and the lifting ratchet 4!. The return movement of the control mechanism. by spring llv from the position ofjFig. 8 to the position of Fig. 5 is resisted by the engagement of the conf trol roller 15 on the control shaft 88 with a further cam surface 18 formed on the control arm 13. This is the relation of the parts in Fig. 6. It will be noted that in this position, the weight of the load on the elevating platform is exerting pressure on the holding pawl 54 tending to break 54 away from teeth 63 of the holding ratchet 55. The manner in which this is done is best shown in Fig. 7 wherein the treadle 66 has been rotated to an extreme position, bringing the cam surface 19 of the control mechanism opposite the control roller 15 of the control shaft 53.

In this position of the control mechanism, the weight of the lifting platform imparts an initial movement to the lifting pawl 54 to break the toggle through the control shaft 53.. Further movement is contributed by the spring 59, which functions to move the control shaft to the position of Fig. 7 through the action of an extending cam surface 80 formed on the holding pawl 54. The action is as follows:

Immediately upon the rotation of the control mechanism to the position of Fig. '7, the weight of the platform acts against holding pawl 54 to break the toggle at the control shaft 53. The spring 59 then aids in rotating the pawl 54 about the control shaft 53, bringing the cam surface 80 of the holding pawl 54 against the holding ratchet 55. This moves the control shaft 53 and its roller 15 against the cam surface 19 of the release mechanism and holds it there. From this point on, the platform is lowered slowly under the control of the check or dashpot I3.

It will be noted that the cam surface 19 is of a form different from the cam surfaces 14 and 18. This is due to the fact that the roller 15,, of control shaft 53 is maintained against surfaces 14 and I8 partly by the weight of the platform, whereas in the relation of the parts in Fig. 7, only the spring 59 functions to maintain the roller 15 against the cam surface I9. In the position of the parts in Fig. '7, the form of the cam surface 19 will prevent the functioning of the spring 18 which tends always to rotate the control mechanism 84 back to its position of Fig. 3.

' With the parts in the position of Fig. '7, the elevating platform, including its casing portion l2, moves downwardly towards the position of Fig. 8. As it does so, an adjustable resetting screw Bl, suitably secured through a connecting bar 82 to the pawl carrier 52, moves against the upper end surface 83 of the holding ratchet 55. In so doing, it tends, of course, to re-align the toggle, in effect, formed by the pawl carrier 52 and the holding pawl 54, thus carrying the control roller 15 out of the depression of the control mechanism formed by cam surface 19.

A very slight movement beyond that of Fig. 8, through the further lowering of the platform, will bring the teeth 62 of the holding pawl 54 just below the first of the teeth 63 of the holding ratchet 55, and will further straighten the toggle through the control shaft 53. This is the position of these particular parts in Fig. 3. This movement will also bring the control roller 15 entirely out of the depression formed by cam surface 19, allowing free rotation of the control mechanism 63 by the spring 10 back to its position of Fig. 3.

This rotation of the control mechanism by spring 18 will bring the cam surface 14 of the control arm 13 against the control roller 15, thus reestablishing the control mechanism to its control position of Fig. 3. At the same time, the lever arm 16 of the control mechanism will be withdrawn from contact with tne downwardly depending arm 1'! of the lifting pawl 48, releasing the pawl 48 for movement back into engagement with the teeth 49 of the lifting ratchet 45. The parts will now be restored for a second lifting and lowering cycle.

While the description above given of the operating structure is probably quite sufficient for an understanding thereof, I shall, for the sake of clarity, review a complete lifting and lowering operation once again.

Starting from the position of Fig. 3, the downward swinging movement of the handle 19 acts through lifting strut 42 to move the lifting ratchet 45 and the casing l2 of the elevating platform ll upwardly due to the fact that the lifting ratchet 45 cannot rotate because of the lifting pawl 48. This upward movement of the elevating platform causes the teeth 62 of the holding pawl 54 to ratchet upwardly relatively to the teeth 63 of the holding ratchet 55, to the position of Fig. 5, whereinthe lifting platform is maintained in a particular elevated position. The lifting handle, which has been swung downwardly to perform the lifting operation, may now be swung upwardly to restore it to the position of Fig. 5, through the ratcheting action of the teeth of the lifting pawl 48 and the teeth 49 of the lifting ratchet 5. From this point, a further downward swinging movement of the handle [9 will further lift the elevating platform.

If, in the position of the parts in Fig. 5, it is desired to release the lifting mechanism so that the lifting handle may be swung downwardly to the position of Fig. 6 to pull the truck, the operator need merely step on the treadle 66, rotating the control mechanism 64 to bring the arm 16 against the downwardly depending arm ll of the lifting pawl 48, thus moving the pawl 48 to the position of Fig. 6 against the resistance of the spring 59. The control mechanism will be maintained in this position due to the coaction of the control roller 14 with the depression of the cam surface 18, the control roller being held in this position by the combined force of the spring 59 and the weight of the platform, the weight of the platform tending to break the toggle, in effect, formed about control shaft 53 through pawl carrier 52 and pawl 54.

If, with the parts in the position of Fig. 6, it now be desired to lower the load, the operator steps on the treadle once again, rotating it to the position of Fig. 7, in which position the toggle, in effect, about the shaft 53 is completely broken, first by the load and then by the spring 59. The deep depression formed by the cam surface 19 cooperates with the control roller 15 to hold the control mechanism in its position of Fig. 7 against the force of the spring 10, which tends always to rotate it back into its initial position of Fig. 3.

As the lifting platform is lowered from its position of Fig. '7 to the position of Fig. 8, the adjustable resetting screw 8| contacts the upper end of the holding ratchet 55, thus tending to restore the toggle, in effect, formed between the pawl carrier 52 and the holding pawl 54, and bringing the control roller 14 from the relatively deep depression 19 of the control mechanism. The spring 10 then rotates the release mechanism back to the position of Fig. 3, just as the control roller 15 is. moved slightly beyond the position of Fig. 8 by the further lowering of the platform. This restores the holding pawl 54 to holding relation relatively to the ratchet 55, and withdraws the lever arm 16 from contact with the downwardly depending arm 14 of the lifting pawl 48, thus restoring the lifting pawl to normal lifting position. Downward swinging movement of the handle at this time without any further operation by the operator of the truck will elevate the platform.

I now claim:

1. In a truck of the class described. a main frame, an elevating platform, a lifting ratchet mounted for rotation on a pivot fixed relatively to said platform, a lifting handle, means whereby predetermined movement of said lifting handle rotates saidratchet on its pivot, and means for locking said'ratchet against rotation by said predetermined handle movement whereby the said movement of said lifting handle moves said ratchet and platform upwardly as a unit relatively to said main frame.

2. In a truck of the class described, a main frame, an elevating platform, a, lifting ratchet mounted for rotation on a pivot fixedrelatively to said platform, a lifting handle, means whereby movement of said lifting handle rotates said ratchet'on its pivot, and a lifting pawl on said platform for locking said ratchet against rotation by said handle in one direction about said pivot, while allowing free rotation in a reverse direction, whereby movement of said handle in one direction moves said ratchet and platform upwardly, while a reverse movement of said handle thereafter moves said ratchet relatively to said pawl and platform to a position from which a second movement of said handle imparts further lift to said ratchet and platform.

3. In a truck of the class described, a main frame, an elevating platform, a lifting ratchet mounted for rotation on a pivot fixed relatively to said platform, a lifting handle pivoted on said main frame and adapted for vertical swinging movement, means connecting said handle and lifting ratchet for rotating said ratchet back and forth on its pivot as said handle swings upwardly and downwardly on its pivot, a lifting pawl mounted on said platform for locking said ratchet against rotation on its pivot as said handle swings downwardly, while allowing free rotation of said ratchet when said handle swings upwardly, whereby downward swinging of said handle moves said ratchet and platform upwardly, while upward swinging of said handle thereafter moves said ratchet on its pivot and relatively to said pawl to a position from which a second downward swinging of said handle will impart further lift to said platform through said ratchet.

4. In a truck of the class described, a main frame, an elevating platform, a lifting ratchet mounted for rotation on a pivot fixed relatively ly and downwardly on its pivot, a lifting pawl mounted on said platform for locking said ratchet against rotation on its pivot as said handle swings downwardly, while allowing free rotation of said ratchet when said handle swings upwardly, whereby downward swinging of said handle moves said ratchet and platform upwardly, while upward swinging of said handle thereafter moves said ratchet on its pivot to a position from which a second downward swinging of said handle will impart further lift to said platform through said ratchet, and holding mechanism for holding said platform in each position to which it is elevated by said handle and lifting ratchet.

5. In a truck of the class described, a main frame, an elevating.platform, a lifting ratchet mounted for rotation on a pivot fixed relatively to said platform, a lifting handle pivoted on said main frame and adapted for vertical swinging movement, means connecting said handle and whereby downward swinging of said handle moves said ratchet and platform upwardly, while upward swinging of said handle thereafter moves said ratchet on its pivot to a position from which,

a second downward swingin of said handle will impart further lift to said platform through said ratchet, holding mechanism for holding said platform in each position to which it is elevated by said handle and lifting ratchet, and release mechanism for moving said lifting pawl from said lifting ratchet and thereafter releasing said holding mechanism to allow lowering of the platform.

6. In a truck of the class described, a main frame, an elevating platform, a lifting ratchet mounted for rotation on a pivot fixed relatively to said platform, a steering head on said main frame, a lifting handle mounted for swinging movement on said steering head while adapted to impart steering movement thereto, means whereby downward swinging movement of said lifting handle in any steering position thereof rotates said ratchet on its pivot, and means for locking said ratchet against rotation whereby the said movement of said lifting handle moves said ratchet and platform upwardly as a unit.

7. In a truck of the class described, a main frame, an elevating platform, a lifting ratchet mounted for rotation on a pivot fixed relatively to said platform, a steering head on said main frame, a lifting handle mounted for swinging movement on said steering head while adapted to impart steering movement thereto, universal means of connection between said lifting handle and ratchet whereby downward swinging movement of said handle in any steering position thereof rotates said ratchet on its pivot, a lift ing pawl mounted on said platform for locking said ratchet against rotation on its pivot as said handle swings downwardly, while allowing free rotation of said ratchet when saidhandle swings upwardly, whereby downward swinging of said handle moves said ratchet and platform upwardly, while upward swinging of said handle thereafter moves said ratchet on its pivot to a position from which a second downward swinging of said handle will impart further lift to said platform through said ratchet. v

8. In a truck of the class described, a main frame, an elevating platform, a lifting ratchet mounted for rotation on a pivot fixed relatively to said platform, a lifting handle, means whereby movement of said lifting handle rotates said ratchet on its pivot, means for locking said ratch-.

et against rotation whereby the said movement of said lifting handle moves said ratchet and platform upwardly as a unit, means for releasing said ratchet from said locking means for free rotation in a lifted position of said platform whereby to free said handle, and means for moving said locking means back into ratchet locking position actuated by movement of said lifting platform to a lowered position.

9. In a truck of the class described, a main frame, an elevating platform, a lifting ratchet mounted for rotation on a pivot fixed relatively to said platform, a lifting handle pivoted on said main frame and adapted for vertical swinghis movement, means connecting said handle and lifting ratchet whereby to rotate said ratchet back and forth on its pivot as said handle swings upwardly and downwardly on its pivot, a lifting pawl mounted on said platform for locking said ratchet against rotation on its pivot as said handle swings downwardly, while allowing free rotation of said ratchet when said handle swings upwardly, whereby downward swinging of said handle moves said ratchet and platform upwardly, while upward swinging of said handle thereafter moves said ratchet on its pivot to a position from which a second downward swinging of said handle will impart further lift to said platform through said ratchet, a release mechanism for separating said lifting pawl and ratchet to release the ratchet from the handle in an elevated position of said platform, and means for moving said lifting pawl and ratchet together actuated by movement of said platform thereafter to a lowered position.

10.,1n a lift truck of the class described, a

main frame, an elevating platform, lifting mechanism for lifting said platform relatively to said main frame, a pivoted lifting handle for actuating said lifting mechanism to lift said platform upon downward swinging movement of said handle, means operated in an elevated position of said platform for positioning at least one part of said lifting mechanism so that vertical swinging of said lifting handle thereafter will no longer actuate said lifting mechanism to lift said platf0, thereby freeing said handle, and means for restoring said part of said lifting mechanism 'to lifting position actuated by movement of said platform thereafter to a lowered position.

11. In a lift truck of the class described, a main frame, an elevating platform, lifting mechanism of the pawl and ratchet type for lifting said platform relatively to said main frame, a pivoted lifting handle for actuating said lifting mechanism to lift said platform upon downward swinging movement of said handle, means operated in an elevated position of said platform for positioning at least one part of said pawl and ratchet lifting mechanism so that vertical swinging of said lifting handle thereafter will no longer actuate said lifting mechanism to lift said platform, thereby freeing said handle, and means for restoring said part of said lifting mechanism to lifting position actuated by movement of said platform thereafter to a lowered position.

12. In a lift truck of the class described, a main frame, an elevating platform, lifting mechanism for lifting said platform relatively to said main frame, a pivoted lifting handle for ac uating said lifting mechanism to lift said platform upon downward swinging movement of said handle, holding mechanism for holding said platform in any elevated position thereof, means operated in an elevated position of said platform for positioning at least one part of said lifting mechanism so that vertical swinging of said lifting handle thereafter will no longer actuate said lifting mechanism to lift said platform, thereby freeing said handle, said means thereafter actuating said holding mechanism to allow lowering of the platform, and means for restoring said part of said lifting mechanism to lifting position and said holding mechanism to holding position actuated by movement of said platform thereafter to a lowered position.

13. In a lift truck of the class described, a main frame, an elevating platform, lifting mechanism for lifting said platform relatively to said main frame, a pivoted lifting handle for actulifting mechanism to lift said platform, thereby freeing said handle, means whereby said means thereafter actuating said holding mechanism to allow'lowering of the platform, and means for restoring said part of said lifting mechanism to lifting position and said holding mechanism to holding position actuated by movement of said platform thereafter to a lowered position, said holding mechanism being restored to its holding position prior to the restoring of said lifting mechanism to its normal position.

14. In a truck of the class described, an elevating platform, a main frame, means whereby said platform is elevated relatively to said main frame, a pair of hinged levers adapted to hold said platform elevated when it has been elevated to a particular position, means whereby said levers are biased for relative pivotal movement about their hinge and out of holding position, and manually operated means for maintaining said levers against said pivotal movement.

15. In a truck of the class described, an elevating platform, a main frame, means whereby said platform is elevated relatively to said main frame, a toggle mechanism adapted to hold said platform elevated when it has been elevated to a particular position, means whereby said toggle mechanism is biased towards collapse and out of holding relation to said platform, and manually operated means for maintaining said toggle mechanism against said collapse.

16. In a truck of the class described, an elevating platform, a main frame, means whereby said platform is elevated relatively to said main frame, a toggle mechanism adapted to hold said platform elevated when it has been elevated to a particular position, means whereby said toggle mechanism is biased towards collapse and out of holding relation to said platform by the weight of said platform, and manually operated means for maintaining said toggle mechanism against said collapse.

17. In a truck of the class described, a main frame, an elevating platform, a lever pivoted to said platform at one end, a control shaft whereby said lever is pivoted to a holding pawl at its other end, a ratchet cooperable with said pawl for locking said platform in any elevated position, said ratchet interlocking with said pawl at a point so related to said control shaft and the pivot point of said lever on said platform whereby the weight of said platform tends to move said control shaft in a direction carrying the pawl away from the ratchet, and a pedal controlled cam for holding said cam shaft against said movement, and movable by said pedal to release said shaft for movement.

18. In a truck of the class described, a main frame, an elevating platform, a lever pivoted to said platform at one end, a control shaft whereby said lever is pivoted to a holding pawl at its other end, a ratchet cooperable with said pawl for locking said platform in any elevated position, a spring for rotating said pawl on said control shaft and against said ratchet, said spring allowing movement of said pawl relatively to said ratchet during the lifting of said platform while preventing reverse movement of said pawl and platform, said ratchet interlocking with said pawl at a point so related to said control shaft and the pivot point of said lever on said platform whereby the weight of said platform tends to move said control shaft in a direction carrying the pawl away from the ratchet, and a pedal controlled cam for holding said cam shaft against said movement, and movable by said pedal to release said shaft for movement.

19. In a truck of the class described, a main frame, an elevating platform, a lever pivoted to said platform at one end, a control shaft whereby said lever is pivoted to a holding pawl at its other end, a ratchet cooperable with said pawl for locking said platform in any elevated position, a spring for rotating said pawl on said control shaft and against said ratchet, said spring allowing movement of said pawl relatively to said ratchet during the lifting of said platform, while preventing reverse movement of said pawl and platform, said ratchet interlocking with said pawl at a point so related to said control shaft and the pivot point of said lever on said platform whereby the weight of said platform tends to move said control shaft in a direction carrying the pawl away from the ratchet, a pedal controlled cam for holding said cam shaft against said movement, and movable by said pedal to release said shaft for movement,.

a lifting mechanism for said truck including a lifting pawl pivoted to said elevating platform, said holding pawl spring acting also on said lifting pawl to urge it into a lifting position, and means whereby said pedal controlled cam moves said lifting pawl out of lifting position and releases said control shaft for moving said holding pawl out of holding position.

20. In a truck of the class described, a main frame, an elevating platform, a lifting ratchet pivoted on said platform, a vertically swinging lifting handle pivoted on said main frame and connected to said ratchet to rotate said ratchet on its pivot when said ratchet is free to rotate or to lift said ratchet and platform as a unit when said ratchet is locked against rotation, a lifting pawl for locking said ratchet against rotation during the swinging movement of said handle in a lifting direction, a holding ratchet, a pawl carrier pivoted on said platform, a holding pawl pivoted on said pawl carrier and cooperable with said holding ratchet to hold said platform in any position to which it is lifted by said lifting handle, means pressing said holding pawl and said lifting pawl against their respective ratchets, the said holding ratchet engaging the holding pawl at a point so related to the pivots of the pawl carrier that said pawl carrier is biased for movement to carry said holding pawl away from holding position, a cam member cooperable with said lifting pawl and said pawl carrier when moved to release position for moving said lifting pawl away from its ratchet and releasing said pawl carrier for movement carrying said holding pawl away from said holding ratchet, a spring pressing said cam away from said release position, said pawl carrier locking said cam in said release position when said pawl carrier is moved to its last named position, and means operated by movement of said elevating frame to a lowered position for moving said pawl carrier so as to reengage said holding pawl and ratchet, and thereby release said cam for movement under said spring pressure into position to release said lifting pawl for movement into engagement with its ratchet.

21. In a truck of the class described, a main frame, an elevating platform, a lifting ratchet pivoted on said platform, a vertically swinging lifting handle pivoted on said main frame and connected to said ratchet to rotate said ratchet on its pivot when said ratchet is free to rotate or to lift said ratchet and platform as a unit when said ratchet is'locked against rotation, a lifting pawl for locking said ratchet against rotation during the swinging movement of said handle in a lifting direction, a holding ratchet, a pawl carrier pivoted on said platform, a holding pawl pivoted on said pawl carrier and cooperable with said holding ratchet to hold said platform in any position to which it is lifted by said lifting handle, means pressing said holding pawl and said lifting pawl against their-respective ratchets, the said holding ratchet engaging the holding pawl at'a point so related to the pivots of the pawl carrier that said pawl carrier is biased for movement to carry said holding pawl away from holding position, a cam member cooperable with said lifting pawland said pawl carrier when moved to release position for moving said lifting pawl away from its ratchet and releasing said pawl carrier formovementcarrying said holding pawl away from said holding ratchet, a spring pressing said cam away from said release position, said pawl carrier locking said cam. in said release position when said pawl carrier is moved to its last named position, and means operated by movement of said elevating frame to a lowered position for moving said pawl carrier so as to reengage said holding pawl and connected to said ratchet against which said ratchet is urged by said spring.

22. In a truck of the class described, a holding ratchet, a holding paw] engaging said ratchet and a cam, means whereby said cam locks said pawl against movement out of ratchet engaging position when said cam is in an initial position, said cam being movable from said initialposition into a second position in which said pawl is'i'eleased normally held in engagement with said ratchet,

from said ratchet, a spring pressing against said cam to move it back to its initial position, means locking said cam against movement to said initial position while said pawl is held away from said ratchet, and means for moving said pawl back into engagement with said ratchet actuated by movement of said platform to a lowered position, thereby releasing said cam for movement back to its initial and pawl locking position.

23. In a truck of the class described, a'holding ratchet, a holding pawl engaging said ratchet and normally held in engagement with said ratchet, a cam, means whereby said cam locks said pawl against movement out of ratchet engaging position when said cam is in an initial position, said cam being movable from said initial position into a second position in which said pawl is released from said ratchet, a spring pressing against said cam to move it back to its initial position, means locking said cam against movement to said initial position while said pawl is held away from said ratchet, and means for moving said pawl back into engagement with said ratchet when said platform is in a lowered position, thereby releasing said cam for movement back to its initial and pawl locking position.

24. In a truck of the class described, a holding ratchet, a holding pawl engaging said ratchet, a control cam, means whereby said cam locks said pawl in engagement with said ratchet when said cam is in its initial position, a spring pressing said cam into its initial position, means for moving said cam into a second position, means whereby said pawl is separated from its ratchet through movement of said cam to its second position, means locking said cam against movement by its spring back to its initial position while said pawl is separated from its ratchet, and means for moving said pawl into engagement with said ratchet actuated by movement of said platform to a lowered position, thereby releasing said cam for movement back to its initial and pawl locking position. i

25. In a truck of the class described, a holding ratchet, a holding pawl engaging said ratchet and normally held out of engagement with said ratchet, a pedal controlled cam, means whereby said cam locks said pawl against'movement out ofratchet engaging position whilesaid cam is in an initial position, said cam being movable from said initial position into a second position in which said pawl is released from said ratchet, a spring pressing against said cam to move it back to its initial position, means locking said cam against movement to said initial position while said pawl is held away from said ratchet, and means for moving said pawl into engagement with said ratchet actuated by movement of said 26. In a truck of the class described, a holding ratchet, a holding pawl engaging said ratchet, a control cam, means whereby said cam locks said pawl in engagement with said ratchet when said pawl is in its initial position, a spring pressing said cam into its initial position, means for moving said cam into a second position, means whereby said pawl is separated from its ratchet upon movement of said cam to said second position, means locking said cam against movement by its spring back into its initial position while said pawl is separated from its ratchet, and means for moving said pawl into engagement with said ratchet actuated by movement of said platform to a lowered position, thereby releasing said cam for movement back to its initial and pawl locking position, a lifting pawl through which said truck platform is elevated, means whereby said pawl is moved by said cam to non-lifting position as said cam moves to release said holding pawl from its ratchet, the return of said cam by its spring to its initial position releasing said lifting pawl for movement to lifting position.

27. In a truck of the class described, a main frame, an elevating platform, a holding ratchet, a pivoted pawl carrier, a pawl pivoted on said pawl carrier and having a tooth for engaging said ratchet to hold said elevating platform in a lifted position, said pawl having a cam surface extending beyond the tooth thereof, a spring pressing said pawl against said ratchet, means whereby said pivoted pawl carrier is movable on its pivot into a holding position and into a release position, the said pawl being movable with said carrier so that the tooth portion of said pawl is pressed by said spring against said ratchet in the holding position of said carrier while in the release position of said carrier the cam portion of said pawl is pressed against said ratchet and the tooth portion is positioned away from said ratchet.

28. In a truck of the class described, a main frame, an elevating platform, a vertical casing forming part of the front end of said elevating platform, a lifting member mounted on a shaft extending transversely through said casing, a portion of said member extending outwardly of said casing for operation, a hydraulic dashpot check in said casing and secured at its upper end near the upper end of said casing and at its lower end to said main frame, a holding device within said casing .and cooperable with holding means extending into said casing from the main frame, a foot treadle outwardly of said casing secured to a shaft supported on said casing for rotation within the casing, and control means for said lifting member and holding device secured on said shaft within said .casing and movable by said pedal.

GEORGE QUAYLE.