US2651428A

US2651428A - Lift truck and attachment therefor

Info

Publication number: US2651428A
Application number: US147310A
Authority: US
Inventors: Benjamin A Dickson
Original assignee: TERMINAL WAREHOUSE Co
Current assignee: TERMINAL WAREHOUSE Co
Priority date: 1950-03-02
Filing date: 1950-03-02
Publication date: 1953-09-08
Anticipated expiration: 1970-09-08

Description

m 8, 1953 B. A. DICKSON 2,651,428

LIFT TRUCK AND ATTACHMENT THEREFOR Filed March 2, 1950 5 Sheets-Sheet l v A H6!' M 15 9; 5 52 r \{yl 25 (9 5 25 f l o 26' 32 B I]? I Q 24 66 I INVEN7 0R:

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Sept. 8, 1953 B. A. DICKSON 2,651,428

LIFT TRUCK AND ATTACHMENT THEREFOR Filed March 2, 1950 s Sheets-Sheet s INVENTQR: Begamz'nfl. 216M072,

A TTORNEYS.

Sept. 8, 1953 B. A. DICKSON 2,

LIFT TRUCK AND ATTACHMENT THEREFOR Filed March 2, 1950 5 Sheets-Sheet 4 i 29 i I l A TTORNE YS.

p 8. 1953 B. A. DICKgON 2,651,428

LIFT TRUCK AND ATTACHMENT THEREFOR Filed March 2, 1950 5 Sheets-Sheet 5 HGJA H5111.

. ATTORNEYS.

Patented Sept. 8, 1953 LIFT TRUCK AND ATTACHMENT THEREFOR Benjamin A. Dickson, Paoli, Pa'., assignor to Terminal Warehouse Company, Philadelphia, Pa., a corporation of Pennsylvania Application March 2, 1950, Serial No. 147,310

8 Claims.

This invention relates to lift trucks and attachments therefor and is particularly applicable to a lift truck having a tiltable mast and a load carrying member, such as a pair of forks, movable vertically on the mast.

This application is a continuation-in-part of my copending applications, Serial Number 24,706, filed May 3, 1948, now Patent #2539233, granted January 23, 1951, and Serial Number 60,606, filed November 17, 1948, and now Patent No. 2,598,515, in which I have described and claimed inventions in a Lift Truck each of which overcomes diificulties encountered in handling large heavy objects such as drums, barrels, bales, rolls, etc. My present invention satisfies all of the objects set forth in the specifications of my previously filed applications and additionally possesses certain advantages which are more particularly described herein.

In operating lift devices of the character described in my aforementioned applications, in Which the load is inclined to permit the forks or other load carrying members of the truck to be inserted beneath the load, the rearward tilting of the mast exerts a force upwardly and rearwardly upon the tool holding arm, with the result that the forks, when connected to the tool holding arm, tend to be raised above the fioor thereby occasionally interfering with the insertion of the forks under the edges of the tilted load. While in my application which bears Serial No. 60,606, filed November 17, 1948, I have disclosed one method for overcoming these difficulties, in which the support for the load gripping device has capacity for swinging and vertical movement independently of the load carrying member, the present invention has similar advantages and is further beneficial in that the distance between the forks and the load gripping device remains substantially constant thereby providing new and effective means for grasping the load.

In accordance with this invention, provision is further made of readily interchangeable article engaging devices and for interchanging or substituting entire article engaging linkages on a lift truck of the character previously described, thereby broadening the range of application of lift trucks equipped with such attachments.

In picking up objects from irregular supporting surfaces, such as the floors of freight cars and the like, difiiculty is sometimes encountered in holding the forks of a lift truck against the floor while they are being slid under the load. It is accordingly another object of the invention to provide a lift truck of the character herein described having fork means substantially unaffected by irregularities in existing floor surfaces for sliding under the load prior to and during the period in which the load is tilted preparatory to lifting on the fork lift truck.

Other objects and advantages, including those derived from simplicity and economy, will become more fully apparent from a description of one embodiment of the invention which follows hereinafter, having reference to the accompanying drawings, whereof:

Fig. 1 represents in side elevation a portion of the forward end of a conventional lift truck equipped with a load carrying attachment of this invention, showing the same in the position which it assumes when about to engage a drum, the mast of the truck being tilted forwardly;

Fig. 2 represents a similar side elevation of said apparatus, showing'the position which the attachment assumes when it grips the drum, the mast being then in a vertical position and the rear portion of the frame being broken away as indicated by the lines and arrows II-II which appear in Fig. 5;

Fig. 3 represents a plan view of the same;

Fig. 4 represents a view similar to Figs. 1 and 2, showing the position which the attachment assumes When it inclines the drum preparatory to lifting it, the mast of the truck being rearwardly tilted and a portion of the frame being broken away as indicated by the lines and arrows IVIV which appear in Fig. 5;

Fig. 5 represents an enlarged front view of the truck, taken as indicated by the arrows V-V of Fig. 2;

Fig. 6 represents a view in perspective of a hook comprising a load engaging element of the lift truck attachment;

Fig. '7 represents a view in perspective of a bale hook comprising another load engaging element of the lift truck attachment;

Fig. 8 represents a fragmentary elevation showing the operation of the load engaging bale hook inengaging and tilting a bale preparatory to lifting;

Fig. 9 represents a fragmentary elevation of the load engaging portion of the device including an extension arm support for handling articles of different heights;

Fig. 10 represents a front View of a portion of the lift truck and the attachment including readily demountable means for securing the attachment to the lift truck;

Fig. 11 represents a sectional view taken as indicated by the lines and arrows XI-X which appear in Fig. 10;

Fig. 12 represents an enlarged fragmentary view of the mounting clamp which appears in Fig. 11;

Fig. 13 represents a fragmentary front view of an alternate structure for mounting the attachment on the truck; and

Fig. 14. represents a fragmentary' side elevation taken as indicated by the lines and arrows XIV-XIV which appear in Fig. 13.

With specific reference to Figs. 1. to: =thei=e is shown an example of the invention as applied to a well known type of lift truck, comprehensively designated at A. The particular truck selected for illustration is mounted upon wheels 2 and includes a tiltable mast 4 of a conventional type which may be tilted forwardly to an angle of about two degrees from the vertical position may be tilted rearwardly to an angle of about ten degrees from the. vertical Such tilting is effected by: movement or power operated rods 5.

To raise and lower the load carrying attachment a hydraulic cylinder 6,. see Fig. 5, is employed. This cylinder actuates a ram 1' having sprocket wheels 8 which serve to raise and lower chains 9 having their lower ends fixed to a carriage I l movable up and down on the mast 4 and guided in such movement by columns l2 and 13. It may be assumed that the truck A is self propelled and that there are available to the operator suitable controls for advancing or reversing, for steering, for operating the ram 1 to raise and lower the carriage, and for tilting the mast forwardly or rearwardly, as desired. Such controls and other details of the truck are not herein described as they are well known in the art and form no part of this. invention.

Upon a transverse shaft-A1 of the movable carriage l i there is pivotally mounted apair of forks M which project forwardly fromv the mast and constitute the load carrying "members. The forks id have capacity for limited angular movement with respect to the carriage H1, each fork being formed with an upstanding arm 48, see Fig. 4, which is adapted to abut against a block 48 depending from a ledge 51 of the carriage to limit relative angular movement between the fiork and the carriage. It will be observed that forks l4, when the carnage. El is lowered to the bottom of the mast, will rest on. the floors In this position they can adjust themselves to any irregularities in the floor surface so that they can readily slide beneath the base of the load, but when the carriage H moves upwardly on the mast, the abutment of the arm 48 against the block 49 prevents the forks from swinging downwardly below the position represented in Fig. 4.

Forks [4 have heels 14d and toes Me, each having flat bottom surfaces. Heel Md and toe Me are both adapted to contact the floor when the mast 4 is in its forward position, see Fig. 1. Each fork M has a raised tine portion l4 intermediate heel Md and toe Me. The function of the forks in engaging, bracing and holding the load is unafiected by irregularities in the floor or by other small obstructions on the floor since these are easily bridged by the raised. tine portions I of forks I4.

Toes Me of forks 14 comprise removable tips made of wear resistant material, and are .a'flixed to tine portions 44-) by means of bolts.

Each fork It has an arcuately shaped forward edge 5'! (Fig. 3) and to the rear thereof is provided with a V-shaped notch 59 and an upstanding flange 58, the latter being adapted to abut against the bottom edge of a drum or the like when the drum is inclined and the fork ends are slid beneath it, as shown in Fig. 4. Thus the load is not only engaged from beneath by the forks 14 but it is seated in a set position in engagement with the upstanding flanges 58 preparatory to raising the carriage l l on the mast 4. Projecting forwardly from the carriage 1 between the forks M is a supporting leg 52 which is also pivoted on the shaft 41 but independently of the forks I4. A pair of parallel rocker arms 15 is pivotally connected to the shaft 58 at the forward end of leg 52. Trunnioned on forks I l is a tool holder arm ld having at its upper end a vertical slot slidabl-y accommodating a transverse shaft 79 for attaching rocker arm if! to tool holder arm ID. Toolholder arm it also has a shelf H15 including a concave forward edge portion M6 for reception of the. drum B when the mast A is tilted rearwardly. Arms to are: free to slide independently of arm H3 along the longitudinal axis of the slot 98. The rocker arms l5 have capacity for vertical movement independently of the tool holder arm if! and for actuating the swinging movement of tool holder arm IB forward and backward in front of the mast 4 Tool holder arm. [9 serves to support a load engaging device in the form of hook 9! which engages the inner portion of the top rim of the drum B, or whatever object is to be transported, and grips or releases the: near edge of same according to whether itsv hock end 92' is swung downwardly or upwardly.

For the handling of drums or like objects having upward projections such. as rims and the like the load engaging device 91 having hook end 92 is pivotally supported on tool holder arm in by means ofv pivot pin 23 which passes through apertures 9.9 and through two of the series of aligned holes 24 in the upper ends of. the tool. holder arms 10, and is held in place by nuts and washers.

Load engaging device 9| has a weight 93 at its hook end 92, see particularly Fig. 6, which serves to lower the hook end 92 by gravity while revolving load engaging device .ilabout its pivot pin 23. Formed integrally with the opposite end of load engaging device 9:! is an upstanding lug 94 having an aperture as suitable for connection to a pulling device, further to be described in detail, for rotating the load engaging device. Si in the opposite direction. and lifting the hook end. 52 to a position above the load .8.

To effect the desired swinging and rocking movements of the load engaging device 91 several extensible and retractable linkages are employed. Swinging of the load engaging device 9| about its pivotal connection with the tool holder arm I!) is accomplished by a link rod 25 linked at one end to aperture 95 of lug 94, and linked at the other end to a turnbuckle 26 which is in turn linked to a horizontal bar 32. Horizontal bar 32 bridges between a pair of pedestals 29 extending upwardly from the shelf 5!. of the movable carriage H. The bar 32 turns freely within the upper ends of the pedestal-s 29. The linkage consisting of link rod 25 and turnbuckle 26 serves to swing the load endaging device 9! upwardly prior to its engagement with the load and incident to its release from the load, such upward swinging being accomplished by and in response to the forward tilting of: the mast- The backward tilting movement of the mast slackens the link rod ZE-tumbuckle 2:6 linkage, permitting load engag- 5 ing'device 9| to swing downwardly by reason of weight 93.

The linkage for rocking the load engaging device 9| forward and backward in front of the mast comprises a pair of parallel links 3| which at their inner ends are pivotally connected to the bar 32 and at their outer ends are pivotally connected to the rocker arms I5 by means of a pivot pin 33. To render the links 3| adjustable and thus provide for loads of varying shapes and sizes, the outer end of each link 3| has a number of holes 34 into any one of which the pivot pin 33 may be fitted. To vary the effective length of the links 3| simply involves removal and resetting of the pivot pin into the appropriate aligned holes 34 at the end of the links 3|. Pedestals 29 are attached to carriage I l by means of angle irons I2 and bolts 13. Similarly shelf 5| is formed integrally with pedestals 29 and is attached to angle irons 19 which are attached by means of bolts I to the lower portion of carriage I I. It will be apparent that the entire linkage attachment, including pedestals 29 and shelf may be removed by unscrewing bolts I0 and I3 and withdrawing shaft 61.

Shaft 50 upon which the rocker arms I5 are mounted for swinging movement, as shown in Fig. 3, terminates at both ends inside the inner edges of the forks I4 and is free to move up and down between the forks. Inasmuch as the rocker arms I5 are pivotally connected to the leg 52, independently of the forks I4, the forks I4 are free to follow surface irregularities in the floor and cannot be raised off the floor by an upward movement of the rocker arms. At the same time the rocker arms I5 are slidably connected to the tool holder arm I0 with capacity for free vertical movement relative to tool holder arm I0, but are constructed and arranged to transmit a substantially horizontal force to actuate the swinging motions of the tool holder arm I0 in response to the tilt of the mast while moving up and down independently of the tool holder arm I0. Tool holder arm I0 is desirably pivotally attached to forks I4, thereby holding the article engaging device 9| at a fixed distance from fork I4 for maximum load engaging effectiveness in which the vertical position of the tool is entirely unaffected by vertical lifting components of the forces exerted by links 3| in swinging and rocking the load engaging device 9|.

In order to render the apparatus more positive in its operation tension springs 62 are preferablv provided. The outer ends of sprin s 62 are afiixed to a bracket 63 which is secured by an adjusting screw 64 to the pivot pin 33 near the lower ends of links 3 I. The inner ends of springs 62 are aflixed to arms 65 (Fig. 2) inte ral with the ledge 5|. In an obvious manner the force of springs 62 tends to retract or collapse the various linkages and draw the parts thereof to the relative positions in which they are represented in Fig. 4. The degree of tension exerted by the springs 62 may be varied by means of the adjusting screws 64. In the fully collapsed condition of the apparatus as shown in Fig. 4, rearwardly extending spacer bars 66 on the rocker arms I5 strike the pedestals 29, limiting the extent to which the rocker arms I5 may swing rearwardly about shaft 50. Similar means for accomplishing the same result may of course be substituted for spacer bars 66.

The movable carriage II near the top. thereof includes a removable bar 61 which passes through linkage mechanism including pedestals 29 is carriage piece 98 which serves to support the entire attachment including links 3|, pedestals 29 and forks I4. Formed integrally with carriage piece 98 is a channel member I00 closely interfitted with lower transverse support 91. Attached to the upper end of carriage plate 98 is a clamp comprehensively designated as I02. Clamp I02 is constructed to engage the back surface of transverse support 96 thereby holding the entire attachment on the mast. While clamp I02 is illustrated in position at the top of carriage piece 98, it is permissible to interchange clamp I02 and channel I00.

Having reference to Fig. 12, the clamp I02 has a clasp flange I03, a top plate I04 integral therewith, a base plate I05 affixed to carriage plate 98, and a lever arm I06 pivotally attached to the base plate I05. A rigid strap I01 is pivotally mounted near the centers of both the lever arm I06 and the top plate I04 and serves to hold the top plate I04 and clasp flange I03 in engagement with transverse support 96 when lever arm I06 is swung about its pivot point toward transverse support 96.

The linkage device is attached to the truck by tilting the mast 4 rearwardly, thereby raising transverse member 91 slightly, positioning channel I00 thereunder, and tilting mast 4 forwardly, thereby fitting member 91 into channel I00. Clamp I02 is then tightened around transverse member 96 securing the entire attachment in place.

Another demountable clamp I I0, see Fig. 10, extends over top of carriage plate 98, hooks over transverse support 96 and has a hook edge H5 in contact with the back surface of transverse support 96. Clamp II 0 is secured to carriage plate 96, which has integral eye members I I I, by means of a shaft 2 which penetrates aligned apertures in eye members III and clamp H0 and is held in place by means of conventional nuts and washers. Such clamps may be used independently or in combination with clamp I02 or a similar clamping device.

Referring to Figs. 13 and 14 wherein another attaching means is represented, channel member I00 is formed integrally with carriage piece 98 and serves to engage the lower transverse support 91. Clamps I20 are separate channels gripping transverse member 96 and carriage piece 98. Shafts I2I project throu h aligned apertures in pedestals 29 and clamps I20 and are held in place by means of conventional nuts and washers. The entire linkage assembly may readily be removed from the truck by withdrawing shafts |2I from the assembly and tilting the mast rearwardly thereby lifting transverse member 9'! and permitting the entire assembly including pedestals 29 and attached carriage piece 98 to slide downwardly relative to transverse member 91, disengaging channel member I 00 from transverse member 91. I In Fig 7 of the drawings there appears an article engaging device in the form of a bale hook I311 which'ha-s a sharp hook end .t3l havmg capacity to penetrate into a package of fibrous or other material such as a bale of cotton, for example. Bale hook I30 has an integral weight 132 near its hook end I3I, an upstanding lug I33 having an aperture I34 suitable for accommodatmg a hook pulling device, and apertures 35 for accommodation of a pivot shaft 23, see Figs. 4 and 8. Bale hook I30 is preferably dimensioned for ready interchangeability with other article engaging means such as load Vengaging device 9! which appears in. Fig. 6. By having on hand numerous interchangeable load engaging devices the operator of the machine may handle many different kinds of loads with speed and convenience.

InFig. 8 there is represented the upper portion of the attachment including bale D and bale hook I36 penetrating the top surface of bale D. The linkage is in its retracted position and the bale D :is. tilted rearwardlyin a manner similar to drum B as represented in Fig. 4. In response to the forward tilt of the mast, link shaft 25 pulls on lug I33 thereby lifting hook end Isl and removing hook I36 from bale D.

For handling loads of dii'frent heights extension arm I40, see Fig. 9, is fitted on the top of tool holder arm I8. Filler piece MI is held in adjustable position inside hollow tool holder arm It by means of set screw I42. A top portion of filler piece I'll protrudes above the top of tool holder arm It thereby providing a base upon which extension arm IE9 is fitted and aligned for support by tool holder arm I9. Extension arm I40 has a series of pairs of holes I43 through any of which the pivot pin 23 may be fitted to support the bale hook I39.

In Fig. 9, the device for lifting the bale hook ISi'r .in response to the forward tilt of the mast is an ordinary piece of twine or other strong flexible line M4. Line I44 when connected to bar 32, or when passed over a pulley on bar 32, under a pulley on transverse shaft 4'! and anchored on the lift truck A, serves to operate the load engaging device to produce the required movements in response to the tilt of the mast. Other means also having the capacity to pull and to slacken in response to the tilt of the mast are likewise eifective in practicing the invention.

The operation of the apparatus of this invention is as follows. Upon the assumption that it is. desired to employ the truck for the handling of a drum, such as represented at B in the drawings, the various parts of the apparatus are first adjusted to suit the particular size of the drum to be handled. In this connection it may be noted that the apparatus is capable of handling other objects of various sizes and shapes. The truck A is driven to a position adjacent to the drum B, such as represented in Fig. 1, the mast 4 being forwardly tilted so that the gripping device Q'I is swung upwardly, and the ends of the forks M being brought to a. position close to the base of the drum B. Thereupon the mast 4 is swung to the vertical position, as represented in Fig. 2. The resulting movement of the various linkages causes the rocker arms I5, tool holder arm III, and the load engaging device 9| to assumev the positions there shown. The drum B is firmly engaged at the top thereof by load engaging device 9| and is ready to be inclined rearwardly.

Next, the operator tilts the mast 4 rearwardly, causing the drum to be inclined from its normal upright position, as represented in Fig. 4. It will be observed that the drum may be so approached by the truck and gripped by the apparatus of thisinvention. that it may be readily separated from a group of similar drums even though they are nested closely together, either alongside each other or one on top of the other. Incident to the advancement of the forward ends of the forks It and the inclination of the drum B the forks- M slide under the raised bottom edges of the drum and. cause such edges to be seated adjacent to the upsanding flanges 58. In this manner the base of the drum is steadied and restrained against sliding rearwardly on the forks. At the same time the V-shaped notches 59 restrain the drum against sliding forwardly on the forks.

The operator then by means of cylinder 6 and ram I raises the movable carriage II with the load thereon. The drum may then be transported to its destination firmly held at top and bottom by the load carrying attachment. The operations involved in releasing and discharging the drum are substantially the reverse of the operations which have been described, the drum being brought to the floor by lowering the carriage on the mast and being uprighted and released by swinging the mast to its forwardly tilted position.

It will further be observed that the various linkages which control the angular position of the gripping device are so related to the carriage and to the forks projecting forwardly therefrom that the operator may at certain times actuate the gripping device by a, movement of the carriage downwardly or upwardly, either in conjunction with a tilting of the mast or without such tilting. This gives the operator two separate means of effecting movements of the gripping device which results in a substantially increased measure of control over the apparatus, particularly when stacking or unstacking drums above the floor level.

Although I have described in considerable detail one example of my invention together with modifications thereof, it will be apparent that the apparatus is capable of a. wide variety of applications and uses and that certain features thereof may be used to advantage without the use of other features. It is to be understood that the specific mechanisms referred to and claimed herein are intended to comprehend all mechanica1 equivalents and reversals of parts which function in a similar manner to accomplish the same result.

I claim:

1. In a lift truck, a truck body, a tiltable mast thereon, a carriage movable up and down on said mast, a load carrying member supported by said carriage, a tool for gripping the load, a support for. the load gripping device including a tool holder arm mounted for forward and backward swinging movement on said load carrying memher, an independently mounted rocker arm, a slotted.- con-nection attaching said rocker arm to said tool holder arm, said rocker arm being effective to actuate forward andbackward swinging movement of said tool holder arm but movable up and down independently of said tool holder arm, and mechanism connected to said mast and to said rocker arm for swinging said rocker arm with respect to said carriage in response to the tilt of the mast, whereby said gripping device is adapted to incline the load preparatory to its being lifted by said load carrying member.

2. In a lift truck for handling an article having an upper rim, a tiltable mast, an article carrying member movable up and down on said mast, a, weighted hook for gripping the upper rim of the article, and mechanism connecting said hook with the mast and supporting it forwardly of the mast in spaced relation thereto, including means whereby the rearward tilting of the mast releases the hook for engagement by gravity with said upper rim and retracts the hook to incline the article at an angle and bring the top rim thereof closer to the mast, and means whereby the forward tilting of the mast returns the article to its original upright position and incidentally releases said hook from its engagement with the article.

3. In a lift truck for handling an article having an upper rim, a tiltable mast, a weighted hook for gripping the upper rim of the article at its near edge, and mechanism connecting said hook and mast and pivotally supporting the hook forwardly of the mast in spaced relation thereto, including a carriage movable up and down on said mast, a load carrying member supported by said carriage, a support for the weighted hook including a hook holder arm mounted for forward and backward swinging movement on said load carrying member, mechanism connected to said hook holder arm and to said carriage for actuating swinging movement of said hook holder arm in response to the tilt of the mast, and mechanism also responsive to the tilt of the mast for releasing said hook, causing it to swing under the influence of gravity about its pivot for engagement with said article.

4. In a lift truck for handling a bale, a tiltable mast, a bale carrying member movable up and down on said mast, a weighted bale hook having a sharp point for piercing the upper surface of the bale, and mechanism connecting said bale hook with the mast and supporting it forwardly of the mast in spaced relation thereto, including means whereby the rearward tilting of the mast releases the bale hook for swinging movement under the influence of gravity to engage the bale, and retracts the bale hook after said engagement to incline the bale at an angle and bring the top thereof closer to the mast, and means whereby the forward tilting of the mast returns the bale to its original upright position and incidentally withdraws the bale hook from its engagement with the bale.

5. In a lift truck, a truck body, a tiltable mast thereon, a carriage movable up and down on said mast, a load carrying member supported by said carriage, a device for gripping the load, a support for said load gripping device connected to said load carrying member with capacity for forward and backward swinging movement on said load carrying member, a removable extension arm at the top of said support, said extension arm holding said gripping device above said support, an independently mounted rocker arm slidably connected to said support to effect the forward and backward swinging motions of the support with capacity to move vertically independently of said support, and mechanical linkage connecting said rocker arm to said mast to swing the support in response to the tilt of the mast.

6. In a lift truck for operation on a supporting surface such as a floor or the like, a truck body, a tiltable mast thereon, a carriage member movable up and down on said mast, a load carrying member in the form of a fork on said carriage,

10 said fork having end portions adapted to contact the supporting surface and raised portions intermediate the ends, a support pivotally mounted on said fork, a load engaging device supported on said fork, and mechanism connecting said carriage and said support for swinging the support forward and backward and connecting and disconnecting the load and the load engaging device all in response to the tilting motion of the mast, said mechanism having capacity to move vertically independently of said support, whereby the lifting force exerted by said mechanism on said support being thereby limited to a value insufficient to raise the ends of the fork above their original positions on the supporting surface.

7. In a lift truck for operation on a supporting surface such as a floor or the like, a truck body, a tiltable mast thereon, a carriage member movable up and down on said mast, a load carrying member in the form of a fork having end portions adapted to engage said supporting surface and raised portions intermediate its ends for bridging irregularities in said supporting surface, said load carrying member being pivotally mounted for limited vertical swinging movement on said carriage, a device for gripping the load, a support for said load gripping device pivotally mounted on said load carrying fork and having capacity to swing forward and backward in front of the mast, a mechanical linkage connected to said mast and to said support to actuate the swinging movement of said support in response to the tilt of the mast, said linkage being constructed and arranged to transmit the forces actuating the swinging motions of the support and having capacity to move vertically independently of said support, whereby the ends of the fork remain in contact with the supporting surface while the mast is being tilted.

8. In a lift truck, a truck body, a tiltable mast thereon, a carriage member movable up and down on said mast, a load carrying member, means for attaching said load carrying member on said carriage, a device for gripping the load, a support for said load gripping device pivotally attached to said lead carrying member with capacity to swing forward and backward in front of the mast, means for mounting said load gripping device on said support, a mechanical linkage connected to said mast and to said support to actuate the swinging movement of said support in response to the tilt of the mast, connecting means including a drive element and a driven element slidable up and down relative to one another, said drive element being operated by the linkage and said driven element attached to said support, said connecting means being constructed and arranged to transmit to said support a force suflicient to actuate the swinging motions of the support, the linkage having capacity to move vertically independently of said support.

BENJAMIN A. DICKSON.

References Cited in the file of this patent