|Publication number||US3749814 A|
|Publication date||Jul 31, 1973|
|Filing date||Nov 6, 1972|
|Priority date||Nov 6, 1972|
|Publication number||US 3749814 A, US 3749814A, US-A-3749814, US3749814 A, US3749814A|
|Original Assignee||Pratt R|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (9), Referenced by (25), Classifications (12)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent Pratt Jul 31, 1973  ELECTRICAL CONDUCTING HYDRAULIC 2,430,921 11/1947 ,Edelmann 285/256 X E 2,883,513 4/1959 Schnabel 174/47 X 3,140,884 7/1964 Brauck 285/149 Inventor: Rlchard Pralt, 1 San 3,343,723 9/1967 Richards 339/15 x Rafael, Kansas City, MO. 64119 3,549,180 12/1970 I MacWilliam 285/256  Filed: Nov. 6, 1972 FOREIGN PATENTS OR APPLICATIONS 2 AppL 303 49 1,750,392 11/1970 Germany 339/16 R 573,007 2/1958 Italy 174/47 52 0.8. CI....., 174/47, 174/74 285/256 i Emniinehlaramie E A skinW V V I a 339/15 fifibrni-Clad'de w. rowegioge h B. Bowman c1211.  Int. Cl. F161 11/12  Field of Search 174/15 C, 47, 74 R,
174/78; 2131/13, 1.6; 280/420, 421,422;  ABSTRACT 2 5 149 25 317/2 J; 339 15 1 R, 1 C, 1 A hydraulic pressure hose adapted for electrical con- 340 320 duction through the steel reinforcing layer of the hose by insulating each hose end from the hose fitting and 5 R f r n Cited by providing each fitting with insulated terminals which UNITED STATES PATENTS extend inwardly to contact the conductive reinforcing 511,188 12/1893 Barnard 174/47 x layer 1,223,864 4/1917 French 174/47 UX 8 Claims, 2 Drawing Figures ,(ll llb H 11 a lOc (0b PATENTEU JUL3 1 3. 749 .814
. l ELECTRICAL CONDUCTING HYDRAULIC HOSE BACKGROUND AND SUMMARY OF THE INVENTION In the field of handling and loading equipment, a vehicle known as a forklift truck is typically used to transport and elevate various bulky and heavy loads in warehouses, plants, docks, storerooms, and the like. Those familiar with such equipment recognize that the forklift normally includes a load carrying platform or station which may be elevated'on a supporting frame or track of hydraulic power to a height substantially above ground level. g
Flexible hydraulic hoses are required in the hydraulic system containing fluid under pressure to provide the lifting force for elevating the load station. Such hoses are carried on pulleys, reels, or combinations of both associated with the supporting frame, commonly referred to as the "mast or upright, in order to permit the hoses to extend when the load station is elevated and to retract when the station is lowered. In this regard, the load station is frequently equipped'with auxiliary attachments such as clam shell arms for gripping large rolls of paper, carton clamps for gripping box-like loads, or rams for pushing a load from the platform, or
similar attachments depending upon the application for It has not been feasible to incorporate the electrical cord with the reels and pulleys carrying the hydraulic hose since the electrical cord tends to stretch in use and the hydraulic hose does not. When stretched, the electrical cord tends to ride off of the pulley, bind up in the hose reel, or otherwise create enough slack in the cord to allow it to become entangled in the upright structure. This at times presents a serious safety hazard, especially to maintenance personnel who mustclimb up as high as twenty or more feet to the top of the upright structure to manually release the load and enable the operator of the forklift truck to move away from the load placed on the stack. Unless the load is manually released by the mechanic, it is possible for the operator to pull the whole stack down on himself and the machine.
Accordingly, it has been necessary to provide separate spring-loaded retracting reels or special pulleys for the electrical cords to permit extension of the cords when the load station is elevated and to permit retraction when the station is lowered. In addition to the extra reels and pulleys necessary, the cords themselves have presented a never ending source of problems and represent substantial maintenance. and expense requirements.
A primary object of this invention is to provide a hydraulic hose for eliminating the need of electrical cords and their associated cord reels and pulleys in applications requiring the use of reinforced hydraulic pressure hoses. I
More particularly, an object of this invention is to provide an electrical conducting hydraulic hose operable to function in a hydraulic fluid system and to also serve as an operating electrical conductor for operating electrical equipment.
Other and further objects of the invention, together with the features of novelty appurtenant thereto will appear in the course'of the following description.
DESCRIPTION OF THE DRAWING In the accompanying drawings, which form a part of the specification and are to be read in conjunction lic fluids through the hose 10. The interior layer 10a is circumferentially wrapped by a reinforcing layer 10b typically comprising an interwoven metallic mesh which provides the necessary strength for the hose to withstand high fluid pressures within the hydraulic system. For the purposes of this invention, it is-necessary that the layer 10b be fabricated from a conductive material and, because of its superior strength characteristics coupled with conductivity, steel is preferable. The reinforcing layer 10b is circumferentially wrapped by an exterior cover 100 fabricated from an insulation material. The interior and exterior layers 10a and 10c may be fabricated from any nonconductive material, such as rubber or plastic.
Each end of the hose l0'is equipped with a hose fitting 11 having a rearward sleeve portion which, as shown in FIG. 2, comprises concentrically aligned sleeves 11a and 11b providing an annulus therebetween into which the end of the hose is inserted. The outside diameter of the sleeve 11a is sized to fit within the inside diameter of the hose l0 and the inside diameter of the exteriorsleeve 11b issized to slip over the outside diameter of the hose 10. The fitting 11 is seand at the top of FIG. 1, or it may be a'male joint as shownin the lower portion of FIG. 1.
Disposed within the annulus between the inner sleeve 11a and the exterior sleeve 11b at the end of the hose 10 is an insulation washer 12 which prevents contact of the reinforcing layer 10b with the fitting 11 which would result in a grounded electrical circuit.
A circular bore He is provided through the exterior shell 11b which receives therein an insulation block or grommet l3 fabricated from a nonconductive material such as plastic or rubber and which is securedto the sleeve 1 lb.
Disposed through the insulation block 13 and protruding radially inwardly is a terminal post 14 which extends through the cover layer 10c of the hose to contact the conductive reinforcing layer 10b. The terminal 14 preferably terminates at its lower end withinthe layer l0band does not extend intothe layer 100. If, on the other hand, the terminal 14 does extend into the inner layer 10a, which may slightlyweak'enthe structural properties of the hose, it is important that the end of the terminal 14 not contact the interior sleeve 11a of the fitting.
The upper end of the terminal 14 extends outwardly from the insulation block 13 in order to provide a post for connecting an electrical lead 15 secured thereto between a pair of nuts 16.
In operation, a hydraulic hose l constructed in accordance with the foregoing principles may be employed to conduit electricity through the terminal 14 at one end thereof and through the reinforcing layer b to the terminal 14 at the opposite end of the hose. ln thismanner, the hydraulic hose may simultaneously op erate in a hydraulic system and also serve to operate electrical equipment by means of the terminal connections at opposite ends of the hose. It should readily be evident at this point that one significant application for my invention is the use on forklifts to operate such auxiliary attachments as carton clamps, clam shells, and the like without the necessary electrical cords and cord reels and pulleys heretofore known in the art.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the invention.
It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.
As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth, or shown in the accompanying drawing, is to be interpreted as illustrative and not in a limiting sense.
Having thus described my invention, 1 claim:
1. A hydraulic pressure hose adapted for electrical conduction, said hose comprising:
a hose section having an interior insulation layer providing a conduit for the flow of hydraulic fluid, an inner reinforcing layer of conductive material encasing said interior insulation layer, and an exterior insulation cover encasing said reinforcing layer;
a first hose connection fitting installed on one end of said hose section without engagement with said reinforcing layer;
a second hose connection fitting installed on the opposite end of said hose section without engagement with said reinforcing layer;
a first electrical terminal mounted near one end of said hose section and having a portion extending through said exterior cover to contact said reina radial bore through which saidsecond terminal pro- 2. The hose as in claim 1, said first hose connection fitting including a radial bore through which said first terminal protrudes to contact said reinforcing layer, and said second hose connection fitting also including trudes to contact said reinforcinglayer. I, I
3. The hose as in claim 2, including a pair of insulation blocks disposed within the bores through said connection fittings to insulate said terminals from contact with said connection fittings.
4. The hose as in claim 1, including a first insulation washer disposed between the end of said hose and said first hose connection fitting and a second insulation washer disposed between the opposite end of said hose and said second hose connection fitting. I
5. The hose as in claim 1, said first and second terminals extending inwardly through said exterior cover to contact and terminate within said reinforcing layer.
6. The hose as in claim 1 wherein said reinforcing layer is fabricated from steel. t
7. A fitting for a reinforced hydraulic pressure hose having an inner reinforcing layer of conductive material, said fitting comprising:
a cylindrical portion sized to fit over the end of said hose;
a neck portion integralwith said cylindrical portion extending outwardly from the end of said hose when said cylindrical portion is fitted over the end of said hose;
a hose coupling connected to said neck portion;
a bore through said cylindrical portion;
a terminal extending through said bore and protruding inwardly from said cylindrical portion a sufficient distance to contact said reinforcing layer when said cylindrical portion is fitted over the end of said hose; and
an insulation block disposed within said bore to insulate said terminal from contact with said cylindrical portion.
8. The fitting as in claim 7, including an insulation washer disposed within said cylindrical portion to insulate the end of said hose from said cylindrical and neck portions.
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|U.S. Classification||174/47, 285/256, 439/192, 174/74.00R|
|International Classification||F16L11/12, F16L11/127, F16L25/00, F16L25/03|
|Cooperative Classification||F16L25/03, F16L11/127|
|European Classification||F16L25/03, F16L11/127|