US3727781A - Lift truck load lifting mechanism - Google Patents
Lift truck load lifting mechanism Download PDFInfo
- Publication number
- US3727781A US3727781A US00104118A US3727781DA US3727781A US 3727781 A US3727781 A US 3727781A US 00104118 A US00104118 A US 00104118A US 3727781D A US3727781D A US 3727781DA US 3727781 A US3727781 A US 3727781A
- Authority
- US
- United States
- Prior art keywords
- mast
- section
- ram
- carriage
- mast section
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
- B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
- B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
- B66F9/075—Constructional features or details
- B66F9/08—Masts; Guides; Chains
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
- B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
- B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
- B66F9/075—Constructional features or details
- B66F9/20—Means for actuating or controlling masts, platforms, or forks
- B66F9/205—Arrangements for transmitting pneumatic, hydraulic or electric power to movable parts or devices
Definitions
- the bending moment created by the load carried on the carriage is counterbalanced by a bending moment derived from load lifting tension elements acting on counterbalancing arms attached to an upper section of the mast, thereby substantially reducing or eliminating bending stresses on the mast regardless of the size of the load being lifted.
- a pair of laterally spaced chains are utilized as the tension elements in conjunction with laterally spaced counterbalancing arms and similarly spaced chain orienting arms connected to a lower section of the mast and/or to truck anchor points so that lateral as well as fore and aft stability of the mast and associated lift truck is increased.
- the mast is oriented in a fixed upright position relative ,to the lift truck and a tilting carriage as disclosed herein is used for tilting the forks or other load lifting device attached to the carriage.
- a tilting carriage as disclosed herein is used for tilting the forks or other load lifting device attached to the carriage.
- Several embodiments of counterbalanced masts and telescoping dual rail mast sections and lift chain reeving arrangements are also disclosed.
- An object of the present invention is to provide an improved load lifting mechanism for industrial and/or off-the-road lift trucks of the type having an extensible load lifting mast and associated load lifting chains actuated by a hydraulic ram to lift a load supported in cantile'ver fashion on a carriage of the mast wherein loadinduced bending stresses are counterbalanced by forces transmitted in tension through the load lifting chains to thereby-provide, in conjunction with other features of the invention, a load lifting mechanism which results in: (l) an'economical and lightweight construction which is efficient and reliable in operation, (2) less strain on the mast parts and truck frame and axle, (3) an increased load lifting capacity, (4) greater stability, (5) lower center of gravity, (6) less power to raise the load, (7) faster lift speed, (8) a smaller oil reservoir in the hydraulic supply system, (9) adaptability to a variety of existing truck designs, (10) a greater range of load lifting capacities for a given design of truck and mast, (11) greater off-center load ratings both fore and aft and side to side, (12) a greater margin of
- Another object is to provide an improved tilting carriage mechanism for lift truck masts which pivots the load carried on the carriage substantially about the center of gravity of the load, thereby reducing the power required to actuate the tilting carriage, and which minimizes the space and structural requirements of the carriage.
- a further object is to provide an improved lift truck equipped with a counterbalanced load lifting mechanism of the aforementioned character which cooperates with an overhead guard for the operator of the truck to provide improved protection for the operator and better support for the mast while reducing the stresses imposed by the mast on the truck frame.
- FIG. 1 is a side elevational view of an extensible load lifting mechanism and lift truck constructed in ac cordance with the present invention with the carriage and mast thereof shown in full lift position.
- FIGS. 2, 3, 4, and 5 are simplified semi-schematic vertical center sectional views respectively showing the mast of FIG. 1 in fully extended position (FIG. 2), about half-way extended (FIG. 3), slightly extended with the carriage at the upper limit of the free lift range of the mast (FIG. 4), and with the mast fully collapsed and the carriage at ground level (FIG. 5).
- FIG. 6 is a fragmentary side elevational view of the mast structure of F IG. 1 with the mast in its fully collapsed condition corresponding to FIG. 5.
- FIG. 7 is a fragmentary vertical section taken on the line 7-7 ofFIG. 6.
- FIG. 8 is a fragmentary side elevational view of the mast of FIG .-l shown in the position of FIG. 3 and with portions broken away to illustrate detail.
- FIG. 9 is a top plan view of the mast of FIG. 1.
- FIG. 10 is a horizontal section taken on the line 10 10 of FIG. 1.
- FIG. 11 is a fragmentary side elevational view of the mast of FIG. 1 with the ram and mast sections shown in telescoped collapsed condition of FIG. 5 but with the carriage and counterbalancing arms removed for clarity.
- FIG. 12 is a fragmentary horizontal section taken on line 1212 of FIG. 11.
- FIG. 13 is'the fragmentary side elevational view of the mast of FIG. 1 shown in the partially extended condition of FIG. 4 with the carriage and counterbalancing arms removed and portions broken away to better illustrate detail.
- FIG. 14 is a fragmentary vertical center sectional view taken on the line 14-14 of FIG. 9 illustrating on an enlarged'scale the hydraulic ram of the load lifting mechanism in fully extended condition.
- FIG. 15 is a vertical sectional view of the ram similar to that of FIG. 14 but showing the ram in its fully collapsed or telescoped condition.
- FIGS. 16, 17, and 18 are horizontal sectional views taken respectively on the lines 16-16, 17-17, and 1818 of FIG. 14.
- FIG. 19 is a fragmentary front elevational view of the lower portion of the mast in collapsed condition illustrating the load lifting carriage of the invention.
- FIG. 20 is a fragmentary side elevational view of the carriage and mast structure shown in FIG. 19 but on a larger scale.
- FIG. 21 is a horizOntal section taken on the line 21 21 of FIG. 20.
- FIG. 22 is a fragmentary side elevational view of the structure shown in FIG. 20 illustrating by solid lines and in phantom line positions the range of tilting movement of the carriage.
- FIG. 23 is a fragmentary perspective semi-schematic view of a second embodiment of a lift mast employing the ramof the first embodiment of FIGS. 122 and a similar chain rigging arrangement applied to a noncounterbalanced four section mast.
- FIGS. 24 and 25 are semi-schematic fragmentary perspective view of third and fourth embodiments respectively of extensible lift truck masts in accordance with the present invention.
- FIGS. 26, 27, and 28 are semi-schematic side elevational views of the second, third and fourth mast embodiment shown respectively in FIGS. 23, 24, and 25 in their respective full-lift positions.
- mast section refers usually to a rectangular framework made up generally of a pair of horizontally spaced and vertically extending rails suitably interconnected by horizontal braces and adapted to telescopically interengage with the rails of another such section of the mast.
- rails refers to the vertical side members of a mast section, which may be millformed beam sections, and which are commonly used in pairs in lift mast constructions as the uprights of a mast section.
- ram refers to the hydraulically operated piston and cylinder unit employed to impart vertical movement to the load lifting mechanism, and preferably comprises a simple twopart ram made up of a cylinder which constitutes the external member of the ram and an internal plunger which telescopes within the cylinder.
- carriage refers to the apron which travels vertically on the uppermost section of the mast and the forks or other associated cantilevered attachment which directly carries the cargo or load to be raised, lowered and/or transported.
- chain refers to the usual flexible load supporting elements which transmit tension loading and operatively interconnect the ram, mast sections and carriage. These elements preferably comprise the well known link and roller type chains since they operate with a minimum of friction and stretch, but other types of chains, cables, belts or equivalent elements may be employed if their stretch factor" is suitably taken into account.
- FIG. 1 The first embodiment of a load lifting mechanism constructed in accordance with the present invention is illustrated inFIGS. l-22 inclusive and comprises a twosection mast 30 having the lifting range of a conventional four-rail" mast.
- mast 30 is shown extended to its full height and mounted in fixed vertical position on a lift truck 32 which may be of the off-the-road type shown or a hard tire industrial type.
- mast 30 has only two sections, a lower, dual rail section 34 supported near its lower end on the front pin 36 of truck 32, and rigidly connected at its upper end to the rear of truck 32 by an overhead framework 38 which also serves as a safety guard for the operator of the truck.
- mast 30 is vertically movea ble and slideably telescopes along the outer sides of section 34 when the two sections overlap in the lower lifting range of the mast.
- Mast 30 is equipped with a load lifting carriage 42 which tracks on section 40, with a two-part ram 44, and with two sets of lift chains 58, 58' and 62, 62'.
- FIGS. 6-22 inclusive Further details of the structure and operation of mast 30 will become apparent from the detailed description of the mast structure as shown in FIGS. 6-22 inclusive. However, it is believed that prefacing such description with an explanation of the structural organization and operating principles of the principal components of mast 30 as shown semi-schematically in FIGS. 2-5 inclusive will better facilitate an understanding of the invention.
- section 40 is shown spaced horizontally out in front or forward of section 34 in order to permit clearer illustration of the chain reeving arrangement, it being understood that in practice section 40 embraces section 34 and thus is vertically aligned therewith as shown in FIGS. 1 and 6-13.
- FIGS. 2-5 inclusive show only the right-hand components (as viewed by the truck operator) of the mast sections and chain rigging. Since much of the mast structure is symmetrical, the left-hand components are generally duplicates of the right-hand components and their reference numerals have been given a prime mark suffix to indicate this relationship.
- carriage 42 has a pair of vertically spaced rollers 46 and 48 linked to an apron 50 of the carriage by a tilting mechanism described hereinafter in conjunction with FIGS. 19-22.
- Rollers 46, 48 track in the outwardly facing channel or groove 52 defined by the channel-shaped rail 54 of section 40 to thereby guide vertical travel of carriage 42 on section 40 and to provide cantilever support for the apron throughout such travel.
- a single hydraulic ram 44 is interposed structurally and functionally between sections 34 and 40 to vertically extend mast 30 and to elevate carriage 42 on section 40.
- the lower member of ram 44 is an external cylinder 56 suspended for vertical movement by a first pair of laterally spaced chains 58, 58' from section 34, and the upper member constitutes the ram plunger which is a cylinder-type piston 60 telescopically received in the upper end of cylinder 56.
- the upper mast section 40 is suspended on plunger 60 by a second pair of laterally spaced chains 62, 62.
- a first pair of counterbalancing arms 64, 64' are rigidly fixed to the upper end of section 40 and extend rearwardly therefrom in outwardly diverging relation to one another on the opposite side of the mast from the forwardly extending forks 66 of carriage 42.
- a second pair of arms 68, 68 are rigidly fixed to the upper end of section 34 and are oriented in the same manner as arms 64, 64.
- a sheave 70 is rotatably supported by arm 64 at the outer end thereof and another sheave 72 is rotatably supported near the fixed end of arm 64 to guide chain 58 along the vertical path of travel of apron 50.
- Lower arm 68 also rotatably carries two chain sheaves 74 and 76, sheave 74 being vertically aligned with sheave 70 near the outer end of arm 68 and sheave 76 being mounted near the junction of arm 68 and section 34.
- a pair of sheaves 78, 78' are journalled on the lower end of ram 44, one on each side of cylinder 56, and another pair of sheaves 80, 80' are journalled on the upper end of plunger 60.
- Chains 58, 58 are each fixed at one end respectively by connections 86, 86 to the upper end of section 34 and have runs 1 16, 116' extending downwardly therefrom to sheaves 78, 71' respectively, thence are trained around sheaves 78, 78, and have runs 114, 114 extending vertically up to sheaves 76, 76 respectively. Chains 58, 58' then run out to and under sheaves 74, 74', then upwardly in a vertical run 1 12, 1 12' to and over sheaves 70, 70, then horizontally to and over the respective sheaves 72, 72, and finally downwardly in vertical runs 113, 113' to connection 88, 88' with the uprights of apron 50.
- the second pair of chains 62, 62' are fixed at one end 82, 82' to the lower end of section 40 and then extend upwardly in vertical runs 63, 63' over sheaves 80, 80 respectively and then downwardly in vertical runs 65, 65' to connections 84, 84 with the upper end of cylinder 56.
- Cylinder 56 is guided for vertical movement relative to section 34 by three horizontally spaced rollers 90, 92 and 94 (see also FIG. 10) preferably journalled on the upper end of section 34 at degree angular intervals for rolling engagement with the outer surface of cylinder 56.
- a pair of guide rollers 96, 96' are rotatably mounted on the lower end of ram-44 below sheaves 78, 78', one on each side of cylinder 56, and respectively track in the inwardly facing channel grooves 98, 98'
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Structural Engineering (AREA)
- Civil Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Forklifts And Lifting Vehicles (AREA)
Abstract
Description
Claims (23)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US66063067A | 1967-08-15 | 1967-08-15 | |
US10411871A | 1971-01-05 | 1971-01-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3727781A true US3727781A (en) | 1973-04-17 |
Family
ID=26801198
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00104118A Expired - Lifetime US3727781A (en) | 1967-08-15 | 1971-01-05 | Lift truck load lifting mechanism |
Country Status (1)
Country | Link |
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US (1) | US3727781A (en) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4024972A (en) * | 1976-02-23 | 1977-05-24 | Hobson Lloyd L | Lift truck apparatus |
US4084715A (en) * | 1976-02-23 | 1978-04-18 | Caterpillar Tractor Co. | Lift truck with means to pivot mast and the fork carriage thereon |
US4496031A (en) * | 1979-04-18 | 1985-01-29 | The Raymond Corporation | Material handling apparatus |
US6059214A (en) * | 1999-02-16 | 2000-05-09 | Cleveland State University | Vertical moving support vehicular attachment |
US6269913B1 (en) * | 1997-07-23 | 2001-08-07 | Steinbock Boss GmbH Fördertechnik | Roller position monitoring device for an industrial lift truck |
US20060104780A1 (en) * | 2004-08-19 | 2006-05-18 | Carsten Schottke | Industrial truck having an enlarged driver's field of vision |
US20130006444A1 (en) * | 2011-07-01 | 2013-01-03 | Cardinal Gibbons High School | Folding Forklift |
US8684654B2 (en) | 2010-08-24 | 2014-04-01 | Quality Stainless Products, Inc. | Wheel assembly positioning device |
US8812196B2 (en) * | 2012-09-14 | 2014-08-19 | Caterpillar Inc. | System and method for payload estimation |
US9302543B1 (en) | 2014-03-31 | 2016-04-05 | Quality Stainless Products, Inc. | Tire and wheel lift |
CN108529492A (en) * | 2018-06-28 | 2018-09-14 | 张维秀 | A kind of goods elevating gear and its application method |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1875103A (en) * | 1930-05-14 | 1932-08-30 | Jaeger Machine Co | Truck |
US3051265A (en) * | 1960-06-06 | 1962-08-28 | Shepard Co Lewis | Fork truck with tri-lift mast |
-
1971
- 1971-01-05 US US00104118A patent/US3727781A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1875103A (en) * | 1930-05-14 | 1932-08-30 | Jaeger Machine Co | Truck |
US3051265A (en) * | 1960-06-06 | 1962-08-28 | Shepard Co Lewis | Fork truck with tri-lift mast |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4024972A (en) * | 1976-02-23 | 1977-05-24 | Hobson Lloyd L | Lift truck apparatus |
US4084715A (en) * | 1976-02-23 | 1978-04-18 | Caterpillar Tractor Co. | Lift truck with means to pivot mast and the fork carriage thereon |
US4496031A (en) * | 1979-04-18 | 1985-01-29 | The Raymond Corporation | Material handling apparatus |
US6269913B1 (en) * | 1997-07-23 | 2001-08-07 | Steinbock Boss GmbH Fördertechnik | Roller position monitoring device for an industrial lift truck |
US6059214A (en) * | 1999-02-16 | 2000-05-09 | Cleveland State University | Vertical moving support vehicular attachment |
US20060104780A1 (en) * | 2004-08-19 | 2006-05-18 | Carsten Schottke | Industrial truck having an enlarged driver's field of vision |
US8684654B2 (en) | 2010-08-24 | 2014-04-01 | Quality Stainless Products, Inc. | Wheel assembly positioning device |
US20130006444A1 (en) * | 2011-07-01 | 2013-01-03 | Cardinal Gibbons High School | Folding Forklift |
US8794386B2 (en) * | 2011-07-01 | 2014-08-05 | Cardinal Gibbons High School | Folding forklift |
US8812196B2 (en) * | 2012-09-14 | 2014-08-19 | Caterpillar Inc. | System and method for payload estimation |
US9302543B1 (en) | 2014-03-31 | 2016-04-05 | Quality Stainless Products, Inc. | Tire and wheel lift |
CN108529492A (en) * | 2018-06-28 | 2018-09-14 | 张维秀 | A kind of goods elevating gear and its application method |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: OLOFSSON CORPORATION, A CORPORATION OF MICHIGAN,MI Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KNICKERBOCKER COMPANY, THE;REEL/FRAME:004884/0774 Effective date: 19871120 Owner name: OLOFSSON CORPORATION, 2727 LYONS AVENUE, LANSING, Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:KNICKERBOCKER COMPANY, THE;REEL/FRAME:004884/0774 Effective date: 19871120 |
|
AS | Assignment |
Owner name: BARCLAYS BUSINESS CREDIT, INC., CONNECTICUT Free format text: SECURITY INTEREST;ASSIGNOR:OLOFSSON CORPORATION, THE;REEL/FRAME:005307/0770 Effective date: 19900502 |
|
AS | Assignment |
Owner name: SHAWMUT CAPITAL CORPORATION, CONNECTICUT Free format text: SECURITY INTEREST;ASSIGNOR:BARCLAYS BUSINESS CREDIT, INC.;REEL/FRAME:007388/0133 Effective date: 19950131 |