US2821264A

US2821264A - Ram construction for lift truck

Info

Publication number: US2821264A
Application number: US478807A
Authority: US
Inventors: Bronislaus I Ulinski
Original assignee: Yale and Towne Manufacturing Co
Current assignee: Yale and Towne Manufacturing Co
Priority date: 1954-12-30
Filing date: 1954-12-30
Publication date: 1958-01-28
Anticipated expiration: 1975-01-28

Description

Jam. 28, 1%8 B. a. uuNsKl RAM CONSTRUCTION FOR LIFT TRUCK 4 SheetsSheet 1 Filed Dec. 30, 1954 INVENTOR. 6 Z do/xhw/ flw rmu u W MFW m /D ATTORA/f) Jan 25%, 195% s. 1. ULINSK! RAM CONSTRUCTION FOR LIFT TRUCK 4 Sheets-Sheet 2 Filed Dec. 50, 1954 INVENTOR. I1 I A TTORNfY B. l. uLlN Kl RAM CONSTRUCTION FOR LIFT TRUCK g un. 8 2

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4 Sheets-Sheet 5 Filed Dec. 30, 1954 INVENTOR. I /MZ/ r C/ ATTORNEY 5. l. ULINSKI RAM CONSTRUCTION FOR LI IIFT TRUCK 4 Sheets$heet 4 Filed Dec. 30, 1954 AMEN 3 v I ll \\l /M/& WY m w w 7 wmww m M 1. 1 1 w. A w 5 2 1A i a] a SH yd T @H M i 42 N United States Patent RAM CONSTRUCTION FOR LIFT TRUCK Bronislaus I. Ulinski, Chicago, 11]., assignor to The Yale & Towne Manufacturing Company, Stamford, Conn., a corporation of Connecticut Application December 30, 1954, Serial No. 478,807

3 Claims. (Cl. 187-9) This invention relates to a truck of the class disclosed in my earlier patent, No. 2,554,930, for a Lift Truck. In that patent I disclose a truck having primary uprights, secondary uprights movable vertically on the primary uprights, and a load carriage movable on the secondary uprights. A pair of sequentially operated rams are utilized with one ram functioning between the carriage and the secondary uprights for lifting the carriage relatively to the secondary uprights, the other ram functioning between the secondary uprights and the primary uprights for lifting the secondary uprights together with the carriage after the carriage has been fully elevated on the secondary uprights.

The contribution of my earlier patent is a very considerable one and has been recognized by the truck industry as one of great value. The invention of this application comprises a contribution over that of my earlier patent in that through my newest invention I eliminate the use of movable hose required for the movement of the hydraulic fluid to the sequentially operated rams of my patented structure. In addition, I eliminate the need for outside piping between the rams, requiring only that fluid be moved from the source of fluid pressure into a stationary part of one ram. I accomplish these things while utilizing extremely simple ram structure, with separate cylinder and piston elements for each ram, rather than the telescoping ram arrangements utilized by others in order to contribute this feature.

In brief, I utilize a ram functioning between the primary uprights and the secondary uprights, and a pair of additional rams functioning between the secondary uprights and the lifting carriage, with the relatively stationary element of each of the pair of rams being fixed to the relatively movable element of the first ram. While I prefer to use a pair of rams operating between the carriage and the secondary uprights, those skilled in the art will appreciate that this may not be necessary in many assemblies and that a single ram may be utilized.

As a further feature of the invention, the ports traversed by the fluid between the rams are formed in the securing means holding the ram elements together, so that no outside piping is required. It will be appreciated that the ports need not actually be formed in the securing means since conceivably the rams could be secured at one point, with fluid carrying pipes positioned between the rams at another point. Therefore, this portion of my invention should be construed as contributing the feature of fluid carrying means between the rams so positioned and related that the said fluid carrying means have no movement relatively to the parts of the rams that are secured to one another.

I have thus outlined rather broadly the more important features of my invention in order that the detailed description thereof that follows may be better understood, and in order that my contribution to the art may be better appreciated. There are, of course, additional features of my invention that will be described hereinafter and which will form the subject of the claims appended ICC hereto. Those skilled in the art will appreciate that the conception on which my disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of my invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of my invention, in order to prevent the appropriation of my invention by those skilled in the art.

Referring now to the drawings:

Fig. 1 shows an industrial lift truck utilizing my novel sequential ram structure.

Fig. 2 shows a front view of my invention.

Fig. 3 is a sectional side view on the line 3-3 of Fig. 2.

Fig. 4 is a longitudinal section showing the construction of the rams.

Fig. 5 is a view taken on the line 5-5 of Fig. 4.

Fig. 6 shows a top plan view of the invention.

Fig. 7 is a cross section on the line 77 of Fig. 2.

Fig. 8 and Fig. 9 show schematically the operation of the rams.

In order that my invention may be readily understood,

.1 show in Fig. 1 a lift truck having a pair of primary uprights 10, a pair of secondary uprights 11 that move vertically on the uprights 10, and a load carriage 12 moving vertically on the secondary uprights 11. It will be well to state, before describing my ram construction in detail, that the particular movements of the carriage and uprights are like those described in my patent, No. 2,554,930, to which I have already referred, with the load carriage 12 lifted first to the upper end of the secondary uprights 11, and the carriage 12 and secondary uprights 11 then lifted together relatively to the primary uprights 10. The actual upright structure that I prefer to utilize is quite similar to that shown in my earlier application Serial No. 346,603, filed April 3, 1953, now Patent No. 2,788,863, having the primary and

secondary uprights

10, 11 aligned relatively to one another in a direction transverse to the longitudinal axis of the truck.

This construction will be best understood from Fig. 7, in which I show the secondary uprights 11 mounted intermediate the primary uprights 10 through rollers 13 that are engaged in channels in the primary uprights. The load carriage 12 is mounted through a pair of brackets 14 at its rear side, these brackets 14 having rollers 15 engaged in the channels of the secondary uprights 11. The carriage 12 preferably is equipped also with guide rollers 16 that engage the sides of the secondary uprights 11 to hold the carriage against transverse movement. The particular arrangement has certain advantages that are well described in my earlier application, but it should be understood that the details through which the carriage and uprights are mounted are not important to an understanding of my present invention. It is important here to know principally that the carriage is mounted to move vertically on the secondary uprights, with these uprights mounted to move vertically on the primary uprights.

In describing the extremely novel sequential ram structure that I contribute by my invention, it will be best to consider first the ram 17 that I utilize for lifting the secondary uprights 11. I shall refer later to the ram 17 as the second ram, however, because other rams that I shall describe act first to lift the load carriage. The ram 17 in the preferred form of my novel structure has a relatively long piston 18 that is mounted at its lower end upon the primary uprights 10 of the truck, as may be seen in Figs. 1 and 3. I show for the particular purpose a bearing plate 19 that is seated upon a bottom cross member 20 on the primary uprights 10, with a reduced end portion 21 on piston 18 engaged in an opening in the plate 19 and cross member 20 and held by a snap ring 22. I prefer to reinforce the plate 19 and cross member 20 through-a pair of vertical plates 23, Figs. 1 and 7, that are attached to an intermediate cross member 24 at the rear side of the primary uprights 10.

A relatively long ram cylinder 25 moves on the piston 18, and I attach this cylinder 25 at its upper end to a top cross member 26, Figs. 3 and 6, that is secured to the rear side of the secondary uprights 11. I utilize for this purpose a vertical bracket 27 that is welded to the rear side of the ram cylinder 25, and that has a base portion 28 secured to the cross member 26 through bolts 29. It will be seen therefore that the cylinder 25 is extendible relatively to the primary uprights 10, and that the second ram 17 is interposed between the primary and

secondary uprights

10, 11 to lift the secondary uprights. The particular ram mounting does, incidentially, support the ram 17 intermediate the pair of secondary uprights 11, with the ram guided between the upper end of the secondary uprights 11 and the lower end of the primary uprights 10.

Before considering the ram 17 in further detail, it will be helpful to refer to the rams 30 that I utilize in my invention for lifting the load carriage 12 relatively to the

uprights

10, 11. I arrange one ram 30 at each side of the ram 17, but in keeping with my invention, I could utilize a single ram if I so desired. Referring particularly to Fig. 4, each ram 30 has a cylinder 31 that is set forth as being relatively stationary and a piston 32 that is extendible relatively thereto in an upward direction. The relatively stationary ram cylinders 31 are approximately onehalf the length of ram cylinder 25, and I attach these cylinders 31 to the relatively movable cylinder 25 of the ram 17, utilizing for this purpose a horizontal plate or beam 33 having openings in which the cylinders are placed and welded. Of course, since ram cylinder 25 is attached to secondary uprights 11, the plate 33 in effect secures the ram cylinders 31 to these uprights 11. a

I prefer to make each

ram cylinder

25 and 31 of th same diameter. All of the

pistons

18 and 32 are then of the same diameter relatively to one another, but it is important to observe that the piston diameter is somewhat smaller than the cylinder bores. A bushing 34 holds each

piston

18, 32 centered at one end of its cylinder, and to guide the other end of each piston in centered relation, I mount a sectional bearing 35 in a groove near the said end of the piston. As best seen in Fig. 5, studs 36 hold the sections of each bearing 35 with their ends in spaced relation, whereby fluid can flow past bearing 35 between the end and side surfaces of the piston. I equip the outer end of each

ram cylinder

25, 31 with a conventional cap 37 that holds a packing 38 about the piston.

I shall now call attention to the fact that I form the piston 18 of the second ram 17 with an axial passage 39, Fig. 4, that extends through the upper end of piston 18. Near the bottom of piston 18 is a port 40 through which a hydraulic supply line 41, Fig. 3, is in communication with axial passage 39, whereby fluid pressure can be applied inside the upper end of ram cylinder 25. The fluid pressure thus applied acts upwardly and, under certain conditions to be described, extends the cylinder 25 of ram 17 relatively to piston 18. In addition, the fluid pressure in the upper end of cylinder 25 acts downwardly past the sectional bearing 35 in this cylinder and along the inside 1 of the cylinder.

It will be remembered that cylinders 31 of rams 30 are rigidly attached to ram cylinder 25, and I am able therefore to utilize rigid passage means for applying the fluid pressure from cylinder 25 to cylinders 31 for operating rams 30. For the particular purpose, I form ports 42, Figs. 3 and 4, that extend between the interior of the ram cylinder 25 and the interior of ram cylinders 31 through the intermediate parts of the mounting plate 33. I have already described the manner in which fluid pressure can pass along the sides of the ram pistons 32 and past the sectional bearings 35 on these pistons. It will be seen therefore that the fluid pressure that is applied through the ports 42 is effective against the ends of pistons 32 for extending the pistons relatively to cylinders 31.

. in a lowered position.

Each ram piston 32 acts upon the load carriage 12 through a chain 43, Figs. 2 and 3, that is reeved over a roller 44 on the top of the piston. The particular mounting of the rollers 44 is not important, but for purposes of description, I show a pin 46 supporting each roller 44 in a slot in the end of the piston. Each chain 43 is anchored at one end through a bolt 47 on the ram securing plate 33, and is attached at its opposed end to a bracket 48 on load carriage12. ,Since the securing plate or beam 33 is attached to the secondary uprights 11 through ram cylinder 25, the chains 43 enable rams 30 to act between the secondary uprights 11 and carriage 12. Those persons skilled in the art will understand that the particular chain arrangement reduces the mechanical advantage of each ram by one-half, since the carriage will move at double the speed of the ram extension. Therefore, by utilizing two rams 30, with their pistons 32 of the same diameter as piston 18, I enable the rams 30 together to exert a lifting force equal to that of the ram 17. However, the rams 30 act to lift the carriage 12 'before ram 17 may act to lift the carriage, because ram 17 must lift the secondary uprights 11 and rams 30 in addition to the carriage.

The flow of the hydraulic fluid during the sequential movements of

rams

17 and 30 will be better understood if we now consider Figs. 8 and 9 of the drawings. Fig. 8

represents schematically the position of the rams when .both the carriage 12 and the secondary uprights 11 are When fluid pressure is applied through port 40 to the ram 17, this pressure flows upwardly in the direction of the arrows against the upper end of ram cylinder 25, and downwardly outside piston 18 and through ports 42. From ports 42, the pressure flows downwardly in rams 30 and then acts upwardly against the ends of the pistons 32 in these rams. Since the load on pistons 32 is less than on piston 18, as set forth above, the fluid pressure extends pistons 32 of rams 30, thereby lifting the load carriage 12 relatively to the secondary uprights 11. When carriage 12 reaches the upper ends of the uprights 11, the outer guide rollers 16 on the carriage move against stops 49 that I show on the secondary uprights 11 in Figs. 2 and 6, thus holding the carriage 12 against further upward movement relatively to uprights 1L Pistons 32 are now in the position represented in Fig. 9, and cylinders 31 have remained relatively stationary, being integral with cylinders 25 of ram 17. Once pistons 32 have moved to the limit of their travel, shown in Fig. 9, the fluid pressure is thereafter efiective through movable cylinder 25 of ram '17 to lift the secondary uprights 11 together with rams 30 and carriage 12 relatively to the primary uprights 10, since both cylinders 31 of the rams 30 are fixed to cylinder 25 of ram 17.

Of course,it isconceivable that rams of different diameters may be utilized toproduce the sequential movements I have described. I do prefer to utilize rams of equal diameter, since the rams are then particularly eflfective to lift the load carriage 12 at the same speed throughout its entire vertical movement. This will be apparent when it is considered that the hydraulic fluid when extending the two rams 30 is divided between these rams, but when moving ram 17 extends this ram alone. If the fluid is applied at a constant rate, with all of the

rams

17, 30 of the same diameter, the fluid will first extend rams 30 at a particular speed, and will then extend ram 17 at exactly double that speed. Since rams 30 act through the load chains 43 that double the effective speed of these rams, and ram 17 acts directly, it will be seen that the load carriage 12 actually moves at the same speed whether lifted relatively to the secondary uprights 11 through the extension of rams 30, orlifted with these uprights 11 through the extension of ram 17.

The sequence in which the

rams

17 and 30 act to lift the load carriage 12 and secondary uprights 11 is actually the same that I describe in my earlier patent, No. 2,554,930. The extremely novel construction that I now contribute does, however, enableme to obtain this sequential movement without the utilization of flexible hydraulic lines between the rams. In fact, by utilizing the ports 42 in my ram securing plate 33, I am able to eliminate all pip ng between the rams. I apply fluid pressure to the entlre ram construction through the single port 40 at the bottom of the ram 17, so that I need merely a single hydraulic line for the lifting mechanism. While accomphshing these things, I do not require a complicated telescopic ram construction, and I am able to utilize exceedingly simple ram structure, with a separate piston and cylinder for each ram. In addition, by securing the ram cylinders to one another, I am able to guide all of the rams in proper aligned relation to the uprights through the attachment of the second ram between the lower end of the primary uprights and the upper end of the secondary uprights. I believe, therefore, that the very considerable advantages of my novel lifting mechanism will be understood, and that those skilled in the art will appreciate fully the value of my invention.

I now claim:

1. In a truck of the class described, primary uprights, secondary uprights mounted for vertical movement relatively to said primary uprights, a load carriage mounted for vertical movement relatively to said secondary uprights, a hydraulic ram unit comprising a pair of small rams and a large ram to which said small rams are juxtaposed with a small ram at each side of the large ram, said large ram including an extensible element and a relatively stationary element, means securing the lower end of the relatively stationary element of the large ram relatively to said primary uprights and against vertical movement relatively to said primary uprights, means securing the upper end of the relatively extensible element of said large ram to the secondary uprights whereby said large ram is held at all times between said secondary and primary uprights and when actuated will lift the secondary uprights relatively to the primary uprights, each small ram including an extensible element and a relatively stationary element, structural means securing the relatively stationary element of each small ram in integral relation to the relatively extensible element of said large ram, said means rigidly fixing the relatively stationary elements of the small rams and the relatively extensible element of the large ram to one another intermediate the ends thereof so that the three rams are held in aligned relationship to one another through said structural means and in operating position between the primary and secondary uprights only through the means that hold the elements of the large ram between the secondary uprights and primary uprights, the construction and arrangement of the three-ram unit being such as to permit its assembly to and removal from the truck as a unit through the positioning of the large ram relatively to the primary and secondary uprights, and flexible means connected to said load carriage and actuated by the extensible elements of said small rams whereby the small rams move said load carriage relatively to the secondary uprights.

2. In a truck of the class described, primary uprights, secondary uprights mounted for vertical movement relatively to said primary uprights, a load carriage mounted for vertical movement relatively to said secondary uprights, a hydraulic ram unit comprising a pair of small rams and a large ram to which said small rams are juxtaposed with a small ram at each side of the large ram, said large ram including an extensible element and a relatively stationary element, means securing the lower end of the relatively stationary element of the large ram relatively to said primary uprights and against vertical movement relatively to said primary upl g 13163115 securing the upper end of the relatively extensible element of said large ram to the secondary uprights whereby said large ram is held at all times between said secondary and primary uprights and when actuated will lift the secondary uprights relatively to the primary uprights, each small ram including an extensible element and a relatively stationary element, a structural metal beam welded between the relatively stationary element of each small ram and the relatively extensible element of said large ram intermediate the ends thereof, said beam rigidly fixing the relatively stationary elements of the small rams and the relatively extensible element of the large ram to one another so that the three rams are held in aligned relationship to one another through said beam and in operating position between the primary and secondary uprights only through the means that hold the elements of the large ram between the secondary uprights and primary uprights, the construction and arrangement of the three-ram unit being such as to permit its assembly to and removal from the truck as a unit through the positioning of the large ram relatively to the primary and secondary uprights, and flexible means connected to said load carriage and actuated by the extensible elements of said small rams whereby the small rams move said load carriage relatively to the secondary uprights.

3. In a truck of the class described, primary uprights, secondary uprights mounted for vertical movement relatively to said primary uprights, a load carriage mounted for vertical movement relatively to said secondary uprights, a hydraulic ram unit comprising a pair of small rams and a large ram to which said small rams are juxtaposed with a small ram at each side of the large ram, said large ram including an extensible element and a relatively stationary element, means securing the lower end of the relatively stationary element of the large ram relatively to said primary uprights and against vertical movement relatively to said primary uprights, means securing the upper end of the relatively extensible element of said large ram to the secondary uprights whereby said large ram is held at all times between said secondary and primary uprights and when actuated will lift the secondary uprights relatively to the primary uprights, each small ram including an extensible element and a relatively stationary element, structural metal means securing the relatively stationary element of each small ram in integral relation to the relatively extensible element of said large ram intermediate the ends thereof, ports formed in said structural metal means for flow of hydraulic fluid between the large ram and the small rams, said structural metal means rigidly fixing the relatively stationary elements of the small rams and the relatively extensible element of the large ram to one another so that the three rams are held in aligned relationship to one another through said structural means and in operating position between the primary and secondary uprights only through the means that hold the elements of the large ram between the secondary uprights and primary uprights, the construction and arrangement of the three-ram unit being such as to permit its assembly to and removal from the truck as a unit through the positioning of the large ram relatively to the primary and secondary uprights, and flexible means connected to said load carriage and actuated by the extensible elements of said small rams whereby the small rams move said load carriage relatively to the secondary uprights.

References Cited in the file of this patent UNITED STATES PATENTS 2,678,746 Gibson May 18, 1954