US2121764A - Hand lift truck - Google Patents

Description

June 21, 1938. QUAYLE HAND LIFT 'rnucx Filed March 8, 1935 5 Sheets-Sheet 1 INVENTOR 2(9} m ATTORNEY June 21, 1938.

G. QUAYLE HAND LIFT TRUCK Filed March 8, 1935 5 Sheets-Sheet 2 INVENTOR BY &m% 7

ATTORNEY June 21, 1938. QUAYLE HAND'LIFT TRUCK Filed March 8, 1935 5 Sheets-Sheet 3 'l NVENTORQ BY ATTORN EY June 21, 1938. G. QUAYLE HAND LIFT TRUCK Filed March 8, 1935 5 Sheets-Sheet 4 INVENTOR BY ATTORNEY ml h a l if M. DI. C D 0N Q mm TM 1 om wm June 21, 1938. a. QuAYLE.

HAND LIFT TRUCK .5 Sheets-Sheet 5 Filed March 8, 1935 ATTORNEY Patented June 21, 1938 UN1TED STATES PATENT OFFICE HAND LIFT TRUCK Application March 8,

22 Claims.

This invention relates to lifting trucks of the hand-lift type. In trucks of this type it is usual to have a main frame equipped with a lifting head on which is mounted a lifting lever or handle adapted to impart lifting movement to an elevating platform or frame for elevating the platform relatively to the main frame. Trucks of this type have various types of lifting mechanism for imparting a lifting movement to the elevating platform upon the downward swinging movement of the lifting handle. Generally, elevating trucks are equipped with parallel links on which the elevating platform is mounted for forward and lifting movement relatively to the main frame, but other means have been utilized such as: inclined planes, cams, etc. While I will describe my invention with reference to an elevating platform mounted for lifting movement upon a series of parallel link members, it should be understood that the invention may be utilized in connection with an elevating platform otherwise mounted relatively to the main frame.

While, also, it is common in the art to utilize the full main frame and an elevating frame or platform, there have been trucks devised in which no main frame as such, is used, a mere lifting head rather than an entire main frame being employed. At this point, I should like to indicate that my invention is just as applicable to a lifting truck having no main frame as it is to the conventional type of truck having both a main frame and an elevating platform.

In elevating trucks, the elevating platform is usually cushioned in its downward descent by a checking mechanism or dashpot' of some sort. My invention is especially adapted for utilization with a lifting truck in which the elevating platform has no check means resisting its lowering movement. In the lift truck of my invention, I utilize pressure on the lifting handle to support the elevating platform in its downward movement, thus substituting the reverse of the lifting power for checking mechanism. This connection between my lifting handle and the lifting means for the elevating platform may be characterized as a two-way connection, since the con nection functions in one way to lift the platform, and in another way to control the lowering of the platform. It will be well to indicate at this point that while several of the features of my invention are particularly applicable to lifting trucks in which there is no check for resisting the downward movement of the elevating plat form, other features thereof are applicable to any type of truck. 7

1935, Serial No. 9,952

A further important feature in the average commercial truck is the feature of the locking of the elevating platform in a fully elevated position, once it reaches that position. In the usual commercial lifting truck of this type, 5 treadle means are employed to release the elevating platform for downward movement at the mere will of the operator, a foot treadle being usually supplied for that purpose. It will be readily understood that in a truck of the type 10 embodied in my invention, in which no cushioning means are present to prevent the swift downward movement of the elevating platform, means must be provided for locking the elevating platform in its elevating position until such time as 16 manual effort is applied to cushion the load by means of the lifting handle as previously indicated. For this purpose, I employ means for locking the elevating platform in a'fully elevated position, which means are deadlocked until such 20 time as lifting pressure is applied to the lifting handle.

More in detail, I provide a holding hook on the elevating platform which is adapted to drop into engagement with a detent on the lifting head of the truck, and to thereafter permit a slight retractive or rearward movement of the elevating platform. The construction of the hook and detent is such that a bayonet joint, in effect, will be formed by the hook and detent by this retractive movement of the elevated platform.

It will be readily appreciated that this locking bayonet joint will only be releasable when the elevating platform is pulled forward a slight amount by the application of lifting effort to the lifting handle. Due to the mounting of the elevating platform on links, in the preferred embodiment of my invention, the retractive movement is easily obtained by the operation of gravity. It is entirely possible, however, for this retractive movement to be obtained by spring pressure as where the elevating is done by means other than links or where the elevation is to a point in which the force of gravity is incapable of acting, as where the links are in a dead center or strictly vertical position when the platform is fully elevated.

In the preferred embodiment of my invention I provide also rather unique means for locking the lifting handle in a vertical position, in which position it may act to push or pull the truck, as may be desired. For so looking the lifting handle, I utilize a treadle member normally spring pressed so as to ride into a position in which a locking extension thereof will cooperate with a shoulder portion attached to the lifting handle for locking the lifting handle in its vertical position. I make further use of this treadle member by providing the same with a cam member which is adapted to release the elevating platform locking means, subsequent to the release of the elevating handle. This I shall describe generally in this next paragraph.

It will be recalled that the platform locking means will deadlock because of the bayonet joint coaction So as to require a forward lifting movement of the elevating platform before it may be released. With the elevating platform in a fully elevated position, it is necessary to depress the treadle to release the lifting handle, which lifting handle may then be downwardly moved to a position in which it is capable of transmitting lifting movement to the elevating platform. A cam is provided on the treadle so that the continued depression of the treadle after its release of the lifting handle will cause the cam to coact with the hook of the platform locking means in a manner to release the hook from looking engagement. Naturally, this release will only take place after sufficient lifting pressure has been applied to the lifting handle to move the elevating platform slightly and release the deadlocking coaction between the hook and detent. Thereafter, the pressure on the treadle will separate the hook from the detent and permit the lowering of the load.

It will be readily appreciated that where the load is extremely heavy, the operator must be well braced in order to effect a slowing down or cushioning of the lowering movement of the elevating platform. In order to insure this bracing position of the operator, the release treadle Is so placed relatively to the lifting handle that the operator must necessarily brace himself in a rearward angular bracing position with one foot on the treadle and his weight applied to the lifting handle before the elevating platform locking means may be released to permit lowering of the elevating platform. This feature of my invention together with the deadlocking of the platform locking means I consider especially effective and necessary for a successful checkless hand lift truck.

'While I have described generally the operation of my invention and have indicated several salient features thereof, there are many other points of importance which I' intend to claim hereinafter as my invention and which I will describe clearly in the specification which follows hereinafter. I do believe, however, that I have made a relatively broad contribution to the art and I feel myself entitled to a rather broad monopoly along the lines of the claims appended hereto. For a rather detailed description of my invention, I shall now refer to the drawings wherein Fig. 1 is a perspective View of a lift truck of my invention showing the lifting handle in a vertical position, and showing the'elevating platform in its fully elevated position. Fig. 2 is an enlarged perspective front end view of the truck shown in Fig. 1. Fig.3 is a view showing the elevating platform about three-quarters lifted. Fig. 4 shows the elevating platform in its fully elevated position, and illustrates the position of the handle at the time the truck is fully elevated and also illustrates the position of the handle just prior to the release of the elevating platform when the same .mustbe lowered. Fig. 5 is a View looking downwardly on the truck while Fig. 6 is a side viewof the same. Fig. 7 is apartial section and side view of the truck showing the elevating platform in its lowered position and with the elevating handle locked in its vertical position. Fig. 8 shows the parts of Fig. 'l but with the elevating platform fully lifted. Fig. 9 shows the parts of Fig. 8 with the treadle depressed sufficiently to release the elevating handle. Fig. 1f) shows the parts of Fig. 9 with the platform locking means released and the handle controlling the lowering movement of the elevating platform.

Referring now more particularly to the drawings and especially to Figs. 1 and 2, reference numeral I0 indicates the main frame of an elevating truck comprising the usual side rails as will be understood by those skilled in the art. At the forward end of the truck there is a lifting head II on which is mounted a caster wheel I2 through means of a bearing member I3. An elevating platform I4 is pivotally supported relatively to the main frame It! by a series of four lifting links I5 in a manner which will alsobe understood by those skilled in this art.

It will be noted that the front links I5 arepivoted at each side to the lifting head I I bymeans of pivot stud members I6, there being sufficient space between the links I5 and the main frame ID to permit of the mounting of lifting sectors. on the pivots I6. These lifting sectors terminate in sleeve-like trunnions I8 in which are mounted the vertical portions of they -han'dle member I9,, as will be quite readily apparent.

The sector members I! have integral .lugslfl which cooperate with the forward link members I5 for moving the same on their pivots Iliand thereby impart a forward and elevating imove ment to the elevating platform I4. Notoniy will these lugs 20 and the sectors I1 elevate the platform Hi, but they are capable of supporting and cushioning the rearward movement of thelinks I5 incidental to the downward movement of the elevating platform It, thus, in effect, taking the place of the usual hydraulic check.

In order to lock the lifting handle I9 in.its vertical position, I utilize a treadle member- 25 pivoted at 26 to the lifting head II as .is'best shown in Figs. 7 and '8, and spring pressed through means of spring 21 in a clock-wise direction about pivot 26. Integrally formed with the treadle member 25 is a detent portion 28 which is adapted to drop into locking. relation withra shoulder 29 formed on the sector member I1. Because of the particular construction it will be readily observed that Whenever the U-handlelIB is moved into its vertical position of Fig; '7, the locking portion 28 of the treadle 25 will-automatically be rotated into locking engagement with the shoulder 29 so as to maintain the handle l9 fixed in its vertical position against downward angular movement.

At the same time, a shouldered portion 30 (shown best in Fig. 8) formed on each sector member I? is adapted to engage thelower rail of the frame III so that the clockwise movement of the handle IS on its pivot I6 is also prevented. In this way, the handle I9 is locked against any movement whatsoever relatively to the lifting head I l of the truck so that the handle may. serve to move the truck forward or rearwardbypushing or pulling on the handle. It will be also understood that the handle is locked automatically;

in the vertical position regardless of the particular position. of the elevating platform. It-will also be noticed that the handle may be released for lifting movement or for free pulling movement by simple pressure on the treadle 25 asis;

best illustrated in Fig. 9, where the treadle is shown in a releasing position and with the handle moved somewhat angularly in a lifting or pulling direction. It is well to indicate at this point that the one piece treadle and hook is a real contribution, but that two piece mechanisms could easily be used if desired.

The treadle 25 has an additional function which I will now attempt to explain. For looking the elevating platform I4 in its elevated position I mount thereon a saddle member 3I on which is pivoted at 32 a hook member 33. I'his hook member is adapted to ride on the cam surface 34 of a detent member 35 best illustrated in Figs. '7, 9, and 10. As the elevating platform is lifted, the hook 33 will ride upwardly on the surface 34 until its nose portion 36 reaches the forward edge of a lug 31 on the detent 35. At this point, the hook 33 will drop over the lug 31. It should be noted that the lug 31 of the detent 35 is cut away as at 39 for cooperation with the cut away portion 38 of the hook 33 so as to form a bayonet joint for the purpose of deadlocking the elevating platform in its elevated position. When the nose 36 of the hook 33 drops over the lug 31 and lifting pressure is taken off the handle I9, there will be a retractive or retrograde movement of the elevating platform I4. This retrograde or retractive movement will be suflicient to move the nose 36 of the hook 33 into interlocking bayonet joint engagement with the lug 3'! as illustrated in Figs. 8 and 9. It is apparent that any pressure brought on the hook 33 in its position of Fig. 8 will be ineffective to release it from the detent 35.

- In the particular truck which I have described, this retractive movement of the elevating platform is obtained simply by the action of gravity on the platform I4. Naturally, where other types of lifting means are used, some spring or other mechanism may be required to impart this slight retractive movement to the elevating platform I4. I am especially desirous of emphasizing this point because my invention is readily applicable to many types of elevating structures and I feel it unnecessary to complicate the description of this invention further by illustrating many other types of lifting mechanisms. Also, while I have shown one form of interlocking and one form of deadlocking means for the lifting hook and detent, it will be quite obvious that other means may bereadily devised for deadlocking the platform locking mechanism in platform locking position.

In order to release the elevating platform from its lifted position of Fig. 8, I utilize a cam portion 40 formed integrally with the treadle 25 and acting as is best illustrated in Figs. 9 and 10 to release the hook 33 from its engagement with the detent member 35. With the platform held in its elevated position shown in Fig. 9, the foot treadle 25 may be depressed from its dotted line position to its full line releasing position to release the handle I9 by Withdrawing the locking portion 28 from coaction with the shoulder 29 of the lifting sector IT. The U-handle I9 may then be moved to the position of Fig. 9 with the lifting lugs 20 of the sector I! against the rear surface of the front links I5 and in a position to impart lifting movement to the elevating platform I4. If the operator will now apply his force to the treadle 25, and will at the same time impart a slight lifting movement to the handle I9, it will be readily appreciated that the locking bayonet joint at 36-3I will be released and that It will be readily appreciated that because theoperator must depressthe treadle 25 at the same time that he applies lifting effort to the handle I9, if he desires to lower the elevating platform fromits position illustrated in Fig. 4, he must naturally assume an angular position somewhat related and parallel to the angular position of the handle I9-shown in Figs. 4 and 10. It will therefore be seen that the construction of the truck is such that the operator must, in order to lower the platform, place himself in a position whereby his weight will be so located that it will tend to resist the lowering of the lifting platform I4 without further thought upon the part of the operator. This is a particularly important feature of the invention.

It should also be appreciated that while in my invention, the application of lifting efiort to actually move the elevating platform is necessary, in order to release the deadlocking coaction of the lifting hook and the detent, other means might be devised for otherwise releasing the interlocking engagement by the mere application of pressure to the handle I9 Without suflicient pressure to produce lifting movement. I intend to claim the several features just described broadly, so as to cover such obvious changes in the mechanical structure of the preferred embodiment of my invention.

While I believe that the operation of the truck will be quite apparent from the description presented, it may be of help in the understanding of the same to describe one complete operating cycle. Normally the elevating platform is in its position of Figs. 6 and '7 and with the treadle 25 in its full line position. The handle I9 is locked in its vertical position by cooperation of the looking members 28 with the shoulders 29 of sectors I1 and by cooperation of the shoulders 30 of the sectors I! with the lower rails of the main frame Ill. The depression of the treadle 25 to the dotted line position illustrated in Fig. 6 releases the sectors l1 and permits movement of the handle I9 to the position of Fig. 3 and from that position to that of Fig. 4. In this position of the parts the elevating platform has been fully elevated and it has then had sufiicient retractive movement to interlock the hook 33 with the detent member 35 so that there can not be a releasing of the same until lifting pressure is once again applied to the handle I9.

The handle I9 may now be moved to its up-,

right position illustrated best in Figs. 1, 2, and 8, where it is again locked in the same way as in Fig. 7. If it is now desired to permit a lowering of the platform I4, the depression of the treadle 25 to its full line position illustrated in Fig. 9 will release the handle I9 so that it may assume the position of Fig. 9. The handle I9 acting through the lugs 20 may then elevate the platform I4 so as to secure a release of the bayonet interlock at 36-31 of the hook 33 and the detent 35, whereupon continued pressure on the treadle 25 will move the hook 33 into the position of Fig. 10 to permit thelowering of the platform, which is easily resisted by the operator whose weight has necessarily been properly positioned by the simultaneous application of manall) frame, an elevating frame, elevating link members disposed between said mainland elevating frames and each pivoted at one end to the main frame and .at the other end to the elevating framaga U handle pivotedto said main frame lifting sectors of substantial size independent of said link members and fixed to said handle for rotation therewith relatively to said link members, and means whereby, said sectors engage said elevating link :members for lifting said elevating frame relatively to said main frame.

In a truck of the class described, a main frame, an elevating frame, elevating links pivoted to --,said elevating frame and to said :main frame, :a-L-l handle pivoted'ito said main frame on the same axis on which said links are pivoted thereto; lifting sectors of substantial size fixed to said handle engaging behind said elevating links for lifting said elevating framawhile permitting free movement of said handle when said elevating frame and links are in elevated position.

a truck of the class described, a main frame, an elevating frame, elevating link members :pivoted to said main and elevating frames and-adapted toimpart forwardand'upward movement'ito said elevating frame, a handle pivoted .to said main frame, lifting sectors of substantial sizes-integral with said-handle and having lugs adapted to engage said link members rearwardly so as torrnove :the same to lift the elevating frame, and alsoto control the reverse movement of said link members to control the lowering of the elevating frame.

.4, Ina truck of the class described, a main frame, anelevating platform, elevating link members pivoted to said main and elevating frames and adapted to impart forward and upward movement to said elevating frame, a lifting head secured to' the forward end of said :main frame, a handle pivoted to said head at each side thereof, :a pair of lifting sectors integral with said handle, one at each side of said head, means whereby said sectorsengage behind said links to effect the elevation of saidplatform, said platform being freely movable downwardly from its elevated position whenreleased, said sectors and handle through said links controlling the lowering movement of said platform :in the same way that they-effect the elevating movement.

'5. Ina truck of the class described, an elevat- 7 ing platform, a lifting handle for elevating said platform, means for locking said platform in an elevatedpositioma foot operated treadle for releasing said locking means, and means whereby said locking means'are deadlocked against release by said treadle until said elevating platform is elevatedaby saidlifting handle slightly beyond said elevated position.

6. in a truck of the class described, an elevating platform, a lifting handle for elevating said platform, means for locking said platform in an elevated position, a foot operated treadle for releasing saidjlocking means, means for deadlocking said locking means to prevent their release by said foot operated treadle, said deadlocking means being releasable upon application of lifting effort to said elevating platform by said handle simultaneous to the application of foot pressure on said foot operated treadle.

' .7-l lnra truck ,of the class described, anelevat- 111a platformflaelifting member adapted to-elevate said platform to a point just beyond its normal elevated position, locking means adapted for engagement in said elevated position of the platform for locking the elevating platform against movement back to its lowered position, means whereby said locking means allows slight'retractive movement of the platform to its normal elevated position, a foot operated treadle for releasing said locking means, means deadlocking said locking means upon said slight retractive moveinent whereby to lock said locking means against separation by said foot operated treadle, said locking means being released when the platform is again moved by said lifting member to said position just beyond its normal elevated position simultaneously with the operation of said foot operated treadle.

8. In a truck of the class described, a main frame, an elevating platform adapted for elevating movement relatively to said main frame, a lifting member on said main frame adapted for swinging movement from a substantially vertical position to a substantially angular position relatively to said vertical position, means of connection whereby said swinging movement imparts lifting movement to said elevating platform, means for locking said platform in its elevated position, said platform being movable by gravity or otherwise to a downward position from said elevated position when said locking means are released, the means of connection between said lifting member and the platform lifting means being two way so that said lifting member ,is movable from said angular position back to its vertical position as said platform is lowered whereby manual effort applied to said member will ease and control the lowering of said platform, foot pedal meansfor releasing said locking means, deadlocking means for said locking meansgpreventing release of said locking means by pressure on the said foot pedal, said deadlocking means being releasable by lifting effort applied to said lifting =member, whereby. simultaneous application ,of pedal pressure and lifting pressure is required :to release said locking means.

9. In a truck of the class described, an elevating platform, a lifting head on said truck, a lifting member on said head having a manually operated handle and'adapted for swinging movement from asubstantially vertical position to a substantially angular position, relatively to said vertical position,- means of connection whereby said swinging-movement imparts lifting movement to said elevating platform, means for looking said .platformin its elevated position, said platform being movable by gravity .or otherwise to ,a downward position from'said elevated 5.13081- tion when said locking means are released, the means of connection between said lifting member, andathe platform lifting means being two way so'it-ha't said lifting member is movable from said angular position back to its vertical position as said :platform .is lowered, whereby manual effort applied to said member willease and control the lowering of said platform, foot'pedal'means for-releasing said locking means, deadlocking means rendering pressure on said foot pedal ineffective to release said locking means, said deadlocking'means :moving out of deadlocking position by lifting :eifort applied to said lifting member, whereby simultaneous application of pedal pressure and lifting pressure is required, said pedal being located .on said truck head .and longitudinally :spaced from the-handle .'on 'said lifting head sothat to depress'lihe pedal and actuate the lifting member the operator is required toassume a backward angular position somewhat parallel to the angular position of the lifting member and withhis weight applied to the lifting member and resisting the gravitational downward movement of said elevating platform.

10. In a truck of the class described, an elevating platform, a lifting head, a lifting member on said head adapted for swinging movement from a substantially vertical position to a substantially angular position relatively to said vertical position, means of connection whereby said swinging movement will impart lifting movement to said elevating platform, means for locking said platform in its elevated position, said platform being movable by gravity or otherwise to a downward position from said elevated position when said locking means are released, the means of connection between said lifting member and the platform lifting means being of a two way character so that said lifting member is movable from said angular position back to its vertical position as said platform is lowered whereby manual effort applied to said member will ease and control the lowering of said platform, foot pedal means for releasing said locking means, deadlocking means whereby pressure on said foot pedal is inoperative to release said locking means, said deadlocking means moving out of deadlocking position upon movement of said platform just beyond its locked elevated position by said lifting member, whereby simultaneous application of pedal pressure and lifting pressure is required to release said locking means.

' 11. In a truck of the class described, an elevating platform, 'a lifting head, a handle pivoted to said head at each side thereof, a pair of lifting sectors integral with said handle, one at each side of said head, and adapted to effect the elevation of said platform, and a pair of detent members on said head cooperable with said sectors for locking the handle and sectors in a fixed vertical position.

12. In a truck of the class described, an elevating platform, a lifting head, a lifting member pivoted to said head, means for locking said member in a fixed vertical position, means for locking said platform in an elevated position, and a single foot operated treadle adapted to release both of said locking means through one sequential operation.

13. In a truck of the class described, an elevating platform, a lifting head, a lifting member pivoted to said head, means for locking said member in a fixed vertical position, means for locking said platform in an elevated postion, a foot operated treadle adapted to release both of said means, and means whereby said treadle in one continuous movement releases said lifting member locking means first and then said platform locking means.

14. In a truck of the class described, an elevating platform, a lifting head, a lifting member pivoted to said head, means for locking said member in a fixed vertical position, means for locking said platform in an elevated position, a foot operated treadle formed as an integral extension of said lifting member locking means and adapted when depressed to release said lifting member locking means, and means on said treadle cooperable with and adapted to release the elevating platform subsequent to the release of the lifting member.

15. In a truck of the class described, an ele vating platform, a lifting head, a lifting handle pivoted to said head, means for locking said handle in a fixed vertical position, means for locking said platform in an elevated position, a foot operated treadle member adapted to release both of said locking means, and means for deadlooking said platform locking means against operation until said handle is first released and is operated to apply slight lifting movement to said platform.

16. In an elevating truck of the class described, an elevating platform, a lifting head, a U handle having its vertical portions pivoted to the sides of said head, sectors secured to said vertical portions and adapted to impart lifting movement to said platform when said handle is swung from a substantially vertical position to a substantially angular position relatively'to said vertical position, means on said head for locking said handle in a vertical position regardless of the position of said platform, means for locking the platform in an elevated position, means whereby said platform locking means are deadlocked against release until application of lifting pressure by said handle, a foot treadle movable for sequentially releasing said handle locking means and said platform locking means by the application of sequential releasing pressure to said means, said foot treadle being arranged to first release the handle to permit its movement to a substantially angular position corresponding to the elevated position of the platform so as to permit the application of pressure on said handle to release said deadlocking means of said platform locking means and to slow down the lowering movement of the platform when its locking means are finally released, said platformlocking means being releasable upon the application of said handle pressure while continuous pressure is being applied to said foot treadle.

17. In an elevating truck of the class described, an elevating platform, a lifting head, a U handle having its vertical leg portions pivoted to said head, means of connection operable by downward swinging movement of said handle to elevate said platform, said means of connection being of a two way character whereby said handle follows the lowering movement of the platform so as to ease the same in its downward movement, a foot treadle pivoted on said head, detent means on said treadle engageable automatically with means on said handle to lock said handle in a vertical position, cooperable hook and detent means on said platform and lifting head engageable when said platform is elevated just beyond its normal elevated position and formed in the nature of a bayonet joint to permit slight retractive movement of the platform, which retractive movement locks the said hook and detent means in said bayonet joint against release, means operable by the depression of the treadle tending to release said hook and detent means subsequent to the release of said handle, said hook and detent means being finally releasable when said released handle moves the platform back to its position corresponding to the point of engagement of said hook and detent, whereupon the treadle pressure will finally separate said hook and detent members.

18. In an elevating truck of the class described, an elevating platform, a lifting head, a U handle having its vertical leg portions pivoted to said head, means of connection operable by downward swinging movement of said handle to elevate said platform, said means of connection being of a two way character whereby said handle follows the lowering movement of the platform so as to ease the same in its downward movement, a foot treadle pivoted on said head, detent means operable by said treadle and engageable automatically with means on said handletolock said handle in a vertical position, cooperable hook and detent means on said platform and lifting head engageable when said platform is elevated just beyond its normal elevated position and formed to permit slight retractive movement, means for deadlocking said hook and detent means by said retractive movement, means operable by the depression of the treadle tending to release said hook and detent means subsequent to the release of said handle, said hook and detent means being finally releasable when said released handle moves the platform back. to its position corresponding to the point of engagement of said hook, and detent,

whereupon. the treadle pressure will finally separate said hook and detent members.

19. In an elevating truck of the class described, an elevating platform, a lifting head, a U handle having its vertical portions pivoted to the sides of said head, sectors secured to said vertical portions, means whereby said sectors impart lifting movement to said platform when said handle is swung from a substantially vertical position to a substantially angular position, means on said head for locking said handle in a vertical position regardless of the position of said platform, means for locking the platform in an elevated position, a member operating sequentially torelease said handle locking means and -.then said platform locking means, said handle being-first released to permit its movement to a substantially angular position corresponding to the elevated position of the platform so as to permit the application of the equivalent of lifting pressure on said handle to slow down the lowering movement of the platform when its locking means are finally released, and means for deadlocking said platform locking means against release by said member, said deadlocking means moving out'of deadlocking position when.

said equivalent lifting pressure for elevating said platform is applied to saidhandle.

20. In a truck of the class described, an. ele-i vating platform, a swinging handle adaptedto" elevate said platform by a downwardly swinging movement, a foot treadle, means whereby said foot treadle locks said swinging handle in a vertical position, said foot treadle being movable in a predetermined direction to release said swinging handle, means for locking said. platform in an elevated position, and a cam .por-

tion on the said foot treadle adapted to'releasesaid platform locking means on .movement of said treadle in said predetermined direction, thehandle lock operating meansbeing so formed:

on said treadle relatively to said cam, that movement of said treadle first releases the handle form in an elevated position, and a cam portion" on the said foot treadle for operating said platform locking means whereby to allow lowering' movement thereof to release said platform.

22. In a truck of the class described, an elevating platform, a swinging handle adapted to elevate said platform by a downwardly swinging movement, a foot treadle, an integral por-" tion of said foot treadle adapted to lock said swinging handle in a vertical position; means 'for' locking said platform in an elevated position, and

a cam portion on the said foot treadle adapted to release said platform locking means, the said integral portion and the said cam portion being sequentially operable on' movement of said treadle to release the handle and thereaftertm release the platform locking means.

GEORGE QUAYLE;

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