US2080304A - Industrial truck - Google Patents

Description

y 1937. c. E. COCHRAN INDUSTRIAL TRUCK Filed April 17, 1936 2 Sheets-Sheet 1 INVENTOR.

Patented May 11, 1937 "UNITED STATES PATENT OFFICE INDUSTRIAL TRUCK Application April 17,

2 Claims.

This invention relates to an industrial truck of the tier-lift type. The general object of the invention is to provide an individual industrial tier-lift truck, of high lift capacity which will be 5 efllcient in operation, strong and rugged in construction, and capable of being economically manufactured and operated.

A more specific object of the present invention is to provide an industrial tier-lift truck with a simple arrangement for mounting a movable elevator guide on a fixed elevatorguide in such a manner that the tendency for the movable guide to sway or get out of alignment withthe fixed guide will be overcome and wherein the reactions 15 on the guide members, due to the load being applied to the movable guide, will be eifectively overcome, and wherein a minimum amount of power will be required to raise the movable guide relative to the fixed guide. 4

Other objects of this invention will become more apparent from the following description, relating to the accompanying drawings, which illustrate a preferred form of the invention. The essential novel characteristics of the invention are summarized in the claims.

In the drawings, Fig. 1 is a side elevation of an industrial truck, incorporating an embodiment of the present invention, certain parts of the truck being broken away, to more clearly illustrate the internal construction thereof; Fig. 2 is a horizontal section, on an enlarged scale, the plane of the section being indicated by the line 2--2 of Fig. 1; Fig. 3 is a vertical section, substantially the same as shown in Fig. 2, the plane of the section being indicated by the line 3-3 of Fig. 1; Fig. 4 is a fragmentary vertical section, taken along the same line as that shown in Fig. 3, but illustrating the movable guide in a raised position.

The invention has been illustrated in the draw- 40 ings as applied to an industrial truck of the type described, illustrated and claimed in Patent No.

1,977,815, issued October 23, 1934, to my assignee,

The Elwell-Parker Electric Company.

The general arrangement of such truck, as shown, comprises a relatively fixed elevated guide A, suitably attached to a truck frame III. The attached guide supports a movable guide B, and the movable guide, in turn, supports a carriage C, including a suitable load-engaging and lifting means, such as a platform D. or other lifting means is adapted to be positioned at a comparatively low level for picking up and depositing loads at such level. The carriage C operates in the movable guide B and is raised and lowered thereon and when the upper limit of The platform 1936, Serial No. 74,863

movement of the carriage in the guide B has been reached, the load-engaging means may then be raised further by extending the movable guide 3 with reference to the attached guides. The raising and lowering of the load is accomplished 5 by suitable power hoists E which may be electrically driven, as shown, or operated by a suitable internal combustion motor, either of which may be variedly positioned with reference to the frame of the truck. Such hoists operate through 10 a special cable and sheave arrangement, as set forth in the patent heretofore mentioned, to raise and lower the platform relative to the movable guide and the movable guide relative to the fixed guide in a predetermined order.

Referring now to Fig. 1, the truck comprises a main chassis or frame I0, having a low slung forward extension l2 and an upright battery, or power unit housing l3. Suitable traction wheels i4 disposed beneath the battery housing support the frame, these wheels being'dirigible or non-dirigible, as desired. The wheels are arranged to be driven by a suitable motor through the usual reduction gearing. The motor is indicated at l5, and is adapted to be controlled by an operator who stands on a rearwardly extending platform I6. The low-slung frameextension i2 is supported by a set of wheels. l'l, preferably dirigibly arranged, and adapted by suitable mechanism, not shown, to be controlled by the operator through a steering arm, or equivalent device, shown above the platform l6 at l8.

The load-engaging platform may be of any convenient type, and is generally indicated at D. The platform is supported by the carriage C, which, as shown, has forwardly extending arms 2| to which the platform is secured. The carriage is also provided with vertically extending arms 22, having guiding rollers 23 and 24 which engage suitable guiding means on the movable elevator guide B. The movable guide B comprises a pair of inwardly facing structural channels 25, with hearing strips 26 mounted between their flanges and on which the rollers 23 are adapted to bear. The rollers 24 of the carriage bear directly against the outer surfaces of the forward flanges of the channels 25. The channels 25 are tied together at their tops by a suitable cap member 21, which serves to maintain them in spacedapart relation. Other similar spacing members may be supplied if desired adjacent the bottom of the channel.

The attached elevated guide A, in which the movable guide B is telescopically arranged, comprises, as shown, a pair of inwardly facing structo the main frame l in any well-known man-' tural channels 30. These channels 30 are secured ner. The rearmost flanges of the channels 30 are each provided with a bearing strip 3 I, against v 'frame member 33, which serve to brace and maintain the channels spaced apart. Also adjacent the upper end of each of these channels 30 is a roller 31, which is rotatably mounted on a suitable stud 38, secured, as by welding, to the web of its respective channels 30 of the fixed guide member. These rollers 31 are adapted to bear against guide strips 39, secured to the outer faces of the webs of respective channels 25 of the movable guide 13.

The arrangement of the rollers 32 and 31, above described, has many advantages in industrial trucks of this type, and especially in those trucks having a hoisting mechanism arranged to raise and lower the load-engaging member in the movable guideway to its maximum height ;before the movable guideway is raised or lowered relative to the fixed guide.

Under ordinary operating conditions, and especially during transportation of a load, the load must be raised a distance suflicient to clear the floor or truck-supporting surface. At the same time it is important that the overall height of the truck be maintained at a minimum, during its transportation from place to place. Obviously, to accomplish this, the movable guide must remain in its lowered position during such transportation, while the carriage must be raised relative to the movable guide.

One type of hoisting mechanism, for accomplishing the purpose above set forth, is shown, described and claimed in the patent heretofore mentioned. Briefly, such mechanism comprises an electric motor 40, arranged through the medium of suitable reduction gearing, (not shown) to drive a pair of winding drums 4|. These drums are mounted on the main frame adjacent its lower end of the elevator structure. A continuous strand of cable, the opposite ends of which are tied to respective winding drums 4|, is used to raise and lower the carriage and movable guide. This cable passes from each drum. Such stretches of the cable are shown in Fig. 3, at 42. These cable stretches extend upwardly to respective sheaves 43, mounted on the fixed guide A in a well-known manner. From the sheaves 43, the respective cable stretches pass downwardly, as indicated at 44, to a second pair of sheaves 45, carried adjacent the lower 'ends of the respective channel members 25 of ber 53. secured to the movable guide B adjacent its upper end. a

The above described arrangement of cable mechanism is such that during the initial application of the load, the winding and cable mechanism will operate with twice the mechanical advantage to raise the platform, as it does to raise the elevated guide B. Hence, the platform will be raised to the limit of its movement before the elevating guide begins its movement. Such a cablemechanism is described more in detail in the patent above referred to, and reference to such patent may be had for a more detailed description of its operation.

Heretofore, different types of mountings between the elevatable guide and the stationary guide have been used with more or less success. In certain instances, the channel members of the guide B have been arranged in slidingcon tact, throughout their length, with the channel members of the stationary guide A. However, it has been found difficult to maintain such guideways clean and free from dirt. Hence, when such sliding contact is utilized, the power demands are such that the hoist motors and their power supply, such as electric batteries, require considerable vehicle platform or housing space. This, of course, creates a truck having a comparatively long frame and wheel base, making such truck diflicult to operate in the narrow, sharp-cornered aisleways of ordinary industrial establishments.

I have maintained the power requirements at a minimum by interposing the anti-friction rollers 32 and 31 between the movable guide and the stationary guide. Arrangements, however, have been provided, such as shown in the patent heretofore mentioned, which utilize anti-friction rollers.

In the past, when rollers have been used, it has been customary to secure two pairs of rollers to the movable guide, adjacent its lower ends. Such construction is shown in the prior patent, heretofore mentioned, and has certain advantages over merely sliding one channel in another. Nevertheless, this construction also required considerable power to raise the movable guide in the stationary guide, and therefore the attendant disadvantages.

By arranging mounting of one pair of rollers (32) on the movable guide adjacent the bottom thereof, and mounting another pair of rollers (31) on the fixed guide adjacent the top thereof, I have added greatly to the rigidity and strength of the structure, as I prevent swaying of the load and movable elevator guide during the transportation of the load from place to place. I also surprisingly decrease the amount of power required to raise the movable guide. Under normal conditions, that is, when the movable guide is in its lowermost position, the movable guide is supported adjacent its upper and lower ends, preventing undue binding of the rollers in the guides.

I find that this improved arrangement of the guides permits the movable guide members to be raised higher in the stationary guide than is possible where both pairs of rollers are carried by the movable guide adjacent its lower end. In the latter instance, the rollers must be spaced apart it is possible, when the truck is being used for comparatively light loads, to raise the movable guide member considerably higher than when a maximum load is being raised and lowered. My arrangement of the rollers is such that I may readily raise them into contact with each other if the weight of the load permits. To prevent damage to the mechanism, the usual adjustable stop mechanism for controlling the maximum raising and lowering of the movable elevator is preferably supplied. Such a mechanism, however, is not illustrated, but reference to the above patent heretofore referred to, may be had, for a full and complete description thereof. Suifice it here to say that the mechanism is readily adjusted to limit the maximum height that the movable guide may be raised by stopping the hoist motor upon reaching such limit. The adjustment is arranged so that it may be manually changed to accommodate either a light or heavy weight load.

From the foregoing description, it will be seen that I have provided an elevating platform truck of the tier-lift type, which is rigid in construction, requires a minimum amount of power, and wherein the movable guide can be raised together with the load a maximum distance consistent with the weight of the load being handled.

I claim:

1. In an industrial tier-lift truck, a main frame, an elongated upright elevator guide comprising a pair of inwardly facing channel members fixed against vertical movement relative to the main frame, an elongated upright guideway carried by eachof said channel members, an elongated upright movable guide comprising a second pair of inwardly facing channel members,a guideway carried by each of said second-named channel members, a roller rotatably mounted on each channel member of the fixed guide adjacent its upper end and adapted to bear against the respective guideways oi the movable guide channels, a roller mounted on each of the movable guide channels adjacent their lowermost ends respectively, said last-named rollers being arranged and adapted to coact with the respective guideways of the fixed guide channels, a load-engaging elevator member mounted for vertical movement on said movable guide, and power-operated means to raise the load elevator engaging member relative to the movable guide and the movable guide to the fixed guide.

2. In an industrial tier-lift truck, a main frame, an elongated upright elevator guide comprising a pair of inwardly facing channel members fixed to the main frame, an elongated upright guideway carried by each of said channel members, an elongated upright movable guide comprising guideways carried by said movable guide and extending into the region between the flanges of the respective channels, a roller rotatably mounted on each channel member of the fixed guide adjacent its upper end and adapted to bear against the respective guideways of the movable guide, a pair of rollers carried by the movable guide adjacent its lowermost end, and adapted to bear against respective guideways of the fixed guide, a load-engaging elevator member mounted for vertical movement on said movable guide, and means to raise first the load elevator engaging member relative to the movable guide and subsequently to raise the movable guide and load-engaging member as a unit relative to the fixed guide.

CLYDE E. COCHRAN.

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