US3638961A

US3638961A - Straddle assembly

Info

Publication number: US3638961A
Application number: US842429A
Authority: US
Inventors: Kurt K Larsen
Original assignee: Blue Giant Equipment of Canada Ltd
Current assignee: Blue Giant Equipment of Canada Ltd
Priority date: 1969-06-25
Filing date: 1969-06-25
Publication date: 1972-02-01
Anticipated expiration: 1989-02-01

Abstract

An adjustable straddle assembly for a materials-handling device which is telescopically adjustable to enable the device to be used with a variety of loads within its design limitations and which facilitates repairs to be made to the straddle members of the assembly without the necessity of taking the device itself out of service during the entire time required to make the repairs. The leg components of the assembly connect with the body components of the assembly in a close tolerance connection.

Description

United States Patent Larsen Feb. 1, 1972 [54] STRADDLE ASSEMBLY 2,819,811 1/1958 Quayle ..214/750 2,957,592 10/1960 Thacker... ..2l2/145 m] Invent Canada 3,162,317 12/1964 Becker ..214/7a0 [73] Assignee: Blue Giant Equipment of Canada Limited,

, pto ntario, Canada Primary ExaminerLeo Friaglia Assistant Examiner-Robert R. Song 2 l d. 25 196 l 2] 1 6 June 9 AttorneyDouglas S. Johnson [21] 1 Appl. No.: 842,429

. [57] ABSTRACT [52] 11.8. C1. ..280/ 150 C, 212/ 145 An adjustabie straddle assembly f a materialsmandling [51] Int. Cl ..B60n 27/00 device which is telescopically adjustable to enabk; the device [58] new of Search 750; 280/150 C; to be used with a variety of loads within its design limitations Zlz/ and which facilitates repairs to be made to the straddle members of the assembly without the necessity of taking the device [561 Reterences cued itself out of service during the entire time required to make UNITED STATES PATENTS the repairs. The leg components of the assembly connect with the body components of the assembly in a close tolerance con- 2,678,746 5/1954 Gibson ..2 14/730 nection 2,557,484 6/1951 Wagner et a1... ..212/145 2,706,120 4/ 1955 Stratton ..2l4/390 2 Claims, 2 Drawing Figures Pmmturm H972 3. 638361 SHEET 1 BF 2 KURT K. LARSEN INVENTOR.

BY D mg M J;@uon

PATENTEDFEB H972 3.838361 SHEET 2 [IF 2 KURT K. LARSEN IN VENTOR.

BY bomsems j fi FIELDOF THE INVENTION This invention relatesv to a straddle assembly for materials handling devices or vehiclesof the type used to load or unload palletizedproducts from public or private transportation carriers and in the warehousingor storage of palletized or bulk products.

DESCRIPTION OF THE PRIOR ART It is common for materials-handling device used to carry or stack palletized or bulk products to have some means in addition to the lifting'means (usually forks) to assist in aligning the product to be lifted (with the device which will do the lifting) and to assist in supportingthe load. Such additional means is commonly known as a straddle assemblyz'lt is normally permanentlyfixed to the materials handling device and includes a pair of legs which project outwardly therefrom adjacent to the ground or floor in the samedii'ection as the lifting forks but usually although not necessarily being more widely spaced than the form members to lie outside the fork members and act as stabilizing members to assist in preventing the device from tipping over under heavy loads. An occurrence which would behighly dangerous to both the vehicle and its operator.

In addition to being required to sustain a sudden unbalanced heavy load condition the straddle assembly is also frequently subjected to'heavy shock loads during even normal use since it is often inadvertently driven into contact with the palletized or bulk product to be moved and is frequently used to turn the product into alignment with the lifting means provided on the device (which means are usually lift forks). Sincethe operators of such materials-handling devices operate the devicesat a rapid speed, it is readily apparent that a shock load as well as any sudden unbalanced load imparted to the straddle assembly would be quite severe when heavy loads are encountered.

For the foregoing reasons, it has-been found necessary to construct straddle. assemblies from durable materials an in a manner to withstand severe impacts so that they can safely handle heavy loads. Heretofore materials handling devices have had fixed width straddle assemblies permanently attached to the body of the device by heavy welding or the like as this wasthe only'form of straddle assembly construction known which would minimize breakage of the assembly. Even with such heavy, solid construction straddle assemblies are subject to breakage and-it will be apparent that damage to such a straddle assembly would be a seriousproblem since it would render thewhole materials handling device. inoperable duringthe timethat repairs were being made to the damaged straddle assembly component.

Another problem associated with former straddle assemblies wasthe factthat the distance between the protruding leg portions was fixed. The device would, therefore, only handle pallets ofa definite size and could only travel through aisles of a definite width. If-a load, of products arrived on pallets which could not behandled by the fixed width materials-handling device costly delays might result until another machine could be located to handle the-palletized products. Since the majority of products are stacked on standard 'size pallets, this problem, although encountered from time to time, as pallet sizes are changed, is perhaps not as significant as the increased burden of storage costs resulting from inability to store palletized productsin narrower aisles because of the fixed width of the device.

In this connection it is common knowledge that the cost of warehousing products has increased substantially over the past several years. necessitating the storage of the maximum volume of goods in the minimum amount of space. In order to economically warehouse palletized'products, it will be appreciated that it wouldbe highly advantageous to able to reduce the amount of aisle space required in the warehouse and to be able to'stack the palletized productsin relatively high piles. To utilize a materials handling device in narrow aisles and to stack palletized products into relatively high piles the device should not be unstable while under load, which condition would be hazardous, and the device should not tend to wander or walk" in which case it might bump into the stacked products with resulting damage to same.

SUMMARY OF THE INVENTION The present invention has for its object the provision of a straddle assembly which will overcome the aforementioned problems. More particularly it is the object of the invention to provide a durable highly serviceable straddle assembly which has a wide range of adjustment to suit substantially all pallet and aisle requirements within its load design limits and to permit economic; utilization of the maximum available storage space in any given warehouse yet will provide the desired stabilizing function for handling heavy loads without walking or giving rise to any other undesirable characteristics.

Another important object is to provide a straddle assembly which can be'readily removed from the materials handling device to facilitate repairs to the straddle assembly component without putting the materials handling device itself out of service and to facilitate storing or shipping of the materials-handling device.

Still another object of this invention is to provide a safe durable and adjustable straddle assembly for materials-handling deviceswhich can be adjusted in width to provide the optimum load support conditions for any load which may become necessary for the device to handle.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and benefits for the present invention will be appreciated from a consideration of the following detailed description of an embodiment of the invention which said description is made in conjunction with the attached drawings in which:

FIG. 1 is a partially exploded broken away view of the straddle assembly of this invention illustrating the manner in which it can be adjusted in relation to or removed from the materials-handling device.

FIG. 2 is a perspective view of a materials-handling device equipped with a straddle assembly produced according to this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT A straddle assembly produced according to this invention comprises a pair of members generally designated at 3 each having mating' leg portions 4 and nonmating leg portions 5. The leg portions, 4 are adapted to be inserted into the open ends 6 of a female member 7, in the form of a" longitudinal rigid box sleeve attached to the materials-handling device generally designated at l to form a telescopic connection therewith.

As is best illustrated in FIG. 2 the leg portions 5 of the members 3 are substantially parallel to the lifting forks 18 attached to the mast assembly 2. The mast assembly 2 is usually attached directly to the main structure of device 1 by any suitable fastening (not shown) and by a suitable number of plates 19 as illustrated in FIG. 1.

The sleeve member 7 is formed from durable suitable plate material, such as cold drawn steel plates welded together to provide a precise uniform interior dimension, and as illustrated in FIG. 1 comprises side plates 8, bottom plate 9 and a plate 10 which forms part of the main structure of the materials handling device which said plate 10 is also attached to other members of the main structure of the materials-handling device generally designated at 11 and 20. The side plate 8 hav' ing openings 17 therein is a separate plate whereas the other side plate 8 can be an extension of plate member 20 as is shown in the drawing of this embodiment of the invention. The thickness of plates 8, 9 and I0 is, of course, determined by the design load requirements for any particular materialshandling device.

Mating leg portions 4 can be formed from solid steel bar or any other similar suitable material which will meet the load design requirements for any particular materials-handling device and which can be accurately cold drawn or machined to mate with a satisfactory tolerance with the sidewalls 8 of the female sleeve member 7. The sleeve member 7 must have a precisely accurate interior dimension. The fit between mating leg portions 4 and sidewalls 8 must be such that movement of members 3 relative to the main body 1 of the materials-handling device will be precluded when the device is assembled even when the device is under load.

One method which has been used to manufacture the sleeve member 7 with the precisely accurate interior dimension required to achieve the satisfactory tolerance fit is now described. An accurately machined or cold drawn mating leg portion 4 can be used as a pattern to form the female sleeve member 7. The said mating leg portion 4 can be given a coating of chrome or other similar satisfactory metal or the like of a sufficient thickness to achieve the desired satisfactory tolerance. Plate member 20 and plate members 19 are then placed in a jig, accurately positioned and welded together. The leg portion 4 which is to be used as a pattern is then inserted into the jig and properly positioned. Plate member 8 shown in the drawings with openings 17 therein, plate member 9 and plate member 10 are then put into the jig and firmly clamped against leg portion 4. Prior to the clamping step, if the leg portion 4 used as the pattern has not been coated as aforesaid with chrome or the like satisfactory shim material can be used and inserted between leg portion 4 and the plates. The plates are then clamped tightly against leg portion 4 and tack-welded firmly together. An additional plate (not shown) is then tack-welded to the side of the plate 10 remote from plate 9 to act as a firewall. All of the plates are then solidly welded to their adjoining plates except for the bottom joint between plate 9 and plate member which joint is solidly tack-welded. The pattern or leg portion 4 is withdrawn from the jig and the said solidly tack-welded seam is then solidly welded.

Nonmating leg portions 5 can also be formed from solid steel bar or any other similar suitable material which will meet the load design requirements for any particular materials handling device. Slots 12 are provided in the nonmating leg portions 5 to receive load-supporting and friction-reducing means such as the rollers 13 mounted on axles 14. The rollers 13 and axles 14, of course, are designed for the load requirements of any particular materials-handling device.

The longitudinal axes of

leg portions

4 and 5 are substantially at right angles to one another but the leg portion 5 can be offset at 15 below the leg portion 4.

When the leg portions are offset the vertical offset serves an important function. Since the leg portions 4 are vertically disposed above the leg portions 5 and the two leg portions 4 support the front end of the materials handling device 1, space is provided under the materials handling device 1 so that the device will ride over any small obstacles on the ground or floor. Because of the inherent characteristic of steel or the like the vertical displacement permits a slight resilient flexing between

leg portions

4 and 5. When the materials-handling device 1 travels over uneven surfaces what might otherwise be damaging impact shocks transmitted to the leg portions by forces created because of the uneven surface and the weight of the load are not likely to cause damage since the slight resilient flexing between the

leg portions

4 and 5 will help to absorb these forces and the load will, in effect, float on the straddle assembly members. With the use of larger wheels or rollers 13 it may not be necessary to offset the

leg portions

4 and 5 in order to have satisfactory clearance under the machine. Even if the

leg portions

4 and 5 are not offset there may be a slight flexing of the members 3. The members 3 should, however, be constructed as solidly as possible for the purpose of keeping the flexing action to a minimum.

As previously stated,

leg portions

4 and 5 can be formed separately from any suitable material such as bar steel. They are usually then joined firmly together by any suitable means such as welding to form the two substantially L-shaped leg members 3.

To assemble the straddle assembly of this invention the materials-handling device is supported in a manner which will permit the insertion of leg portions 4 into openings 6. The tolerance between the precisely accurate interior dimension of the sleeve member 7 and the accurately cold drawn or machined leg portions 4 are then carefully checked at this time to be sure that the leg portions 4 are a close sliding nonrotatable fit in the sleeve so that the members 3 will be precluded from moving or twisting relative to the main structure of the materials-handling device which such movement would give rise to the device walking" while under load. Provided that the tolerance is satisfactory leg portions 4 are then inserted the required distance into the sleeve 7 to give the desired straddle assembly width. When the leg portions 4 have been inserted the required distance they are then firmly locked in position by tightening the fastening devices, such as setscrews 16, which are brought into contact with leg portions 4 through tapped openings 17 in the appropriate plate 8.

When the setscrews 16 have been thoroughly tightened the straddle assembly is ready for use and will support the main structure of the materials-handling device 1.

In order to adjust or replace either leg portion 3 of the straddle assembly it is simply necessary to raise the materials-handling device 1 a sufficient distance from the floor surface to take the load off the load-supporting and friction-reducing members 13 so that either leg portion 4 can be moved relative to the sleeve 7 in either direction a sufficient distance for the required adjustment or completely for repairs.

It will be obvious to those skilled in the art that it would also be an embodiment of the invention to replace the female member 7 by a hydraulic power means such as a piston cylinder in which case the female member 7 would be the hydraulic cylinder and leg portions 4 would be the pistons.

The advantages of the straddle assembly of this invention will be obvious to those skilled in the art as will be other embodiments of this invention of which the specific assembly above described is only one embodiment and is not to be taken as other than illustrative of the invention described and claimed herein.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An adjustable straddle assembly for a materials-handling device having a main structure, said assembly comprising an angular sleeve structure formed at the bottom of said main structure and integral therewith to extend transversely of the materials-handling device, a pair of straddle members each comprising a first leg having an extended free end solid bar portion of precisely uniform angular cross section adapted for telescopic insertion into one end of said sleeve and a second leg having a solid bar portion integrally secured to the first leg and disposed substantially at right angles to said first leg to project substantially horizontally forward of and away from the main structure of said device when the free end portion of the first leg is inserted into said sleeve structure, said second leg having load-supporting, friction-reducing means adjacent its free end to contact the surface on which said device is supported when in use, the free end solid bar angular construction first leg portions of said straddle members being identical, the interior of said sleeve structure being patterned from a free end solid bar angular cross section first leg portion and having a configuration precisely identical to the precisely uniform angular cross section first leg portions of said straddle members and having a close tolerance fit therewith to transfer load counterbalancing torque applied through said second legs to said first legs to said main structure while maintaining said first leg portions and said sleeve structure against relative turning movement, and releasable means operating through a wall of said sleeve structure for positively locking said angular first leg portions from movement longitudinally within said sleeve structure under impact to fix said second arms in a position of desired separation.

1. An adjustable straddle ancmbly as claimed in claim I in which said angular cross scction first leg portions of said straddle members and the interior of said sleeve suucture are rectangular in cross section.

Claims

2. An adjustable straddle assembly as claimed in claim 1 in which said angular cross section first leg portions of said straddle members and the interior of said sleeve structure are rectangular in cross section.