US3230717A

US3230717A - Loading gear

Info

Publication number: US3230717A
Application number: US366096A
Authority: US
Inventors: Alden Lars Anders Gustaf
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-05-08
Filing date: 1964-05-08
Publication date: 1966-01-25
Anticipated expiration: 1983-01-25

Description

Jan. 25, 1966 A. G. ALDEN 3,230,717

LOADING GEAR Filed May 8, 1964 M wwpwg W United States Patent 3,230,717 LOADING GEAR Lars Anders Gustaf Aldn, Postlada 5150, Vaderhrunn,

Nykoping, Sweden Filed May s, 1964, Set. No. 366,096 2 Ciaims. ca. 6054.5)

The invention relates to an improved loading gear having its load supporting portion pivoted in such a way to a horizontal axis at one end of at least one supporting arm pivoted to an upright frame member about a horizontal axis, that the load supporting portion independently of the pivotment of the supporting arm relative to the frame member always occupies the same angular position relative to the ground by actuation of two coacting hydraulic operating cylinders one of which is pivotally mounted between the load supporting portion and the supporting arm while the other operating cylinder is pivotally mounted between the supporting arm and the frame member. The characteristic features of the invention reside in that the operating cylinders are doubleacting and have their operating chambers communicating in pairs through direct conduits whereby an entirely closed system is formed between the operating cylinders. The invention thus provides the advantage that the load supporting portion is controlled without intervening pump, valves and tank.

The invention is diagrammatically illustrated by way of example in the accompanying drawing which in side elevation shows the loading gear with the supporting arm thereof in a horizontal position.

1 designates the upright frame member of a loading gear, and a supporting arm 2 is pivoted at 3 to the upper end of the frame member 1. The load supporting portion 4 is pivoted about a horizontal axis 5 at the free end of the supporting arm 2 remote from the frame member 1. The load supporting portion 4 consists of a loading plate 6 and a vertically upwardly directed support 7 making a right angle with the plate 6.

A hydraulic operating cylinder 8 is pivotally mounted between the vertical support 7 of the load supporting portion 4 and the supporting arm 2 while another hydraulic operating cylinder 9 is pivotally mounted between the supporting arm 2 and the frame member 1. The pivot points 10 and 11 of the operating cylinder 8 on the load supporting portion 4 and the supporting arm 2 are so disposed as to form, with the pivot point 5 of the load supporting portion 4 on the supporting arm 2, the corners of a triangle which is similar or congruent with the triangle which the pivot points 12 and 13 of the operating cylinder 9 on the supporting arm 2 and the frame 1 form with the pivot point 3 of the supporting arm 2 on the frame 1.

The hydraulic operating cylinders 8 and 9 are doubleacting and their operating chambers communicate in pairs through direct conduits 1d and 15. An entirely closed system is thus formed between the operating cylinders 8 and 9. The operating cylinder 8 interposed between the load supporting portion 4 and the supporting arm 2 has its operating chamber, which adjoins the load supporting portion 4, in direct communication through conduit 14 with the operating chamber of the operating cylinder 9 interposed between the supporting arm 2 and the frame 1, said last mentioned operating chamber adjoining the frame member 1. The other two operating chambers of the operating cylinders 8 and 9 are directly interconnected through the conduit 15.

For example when the supporting arm 2 is swung upwards so that the angle between the supporting arm 2 and the frame member 1 is increased, the piston in the operating cylinder 9 will reduce the volume of the operating chamber adjoining the supporting arm 2 whereas the volume of the operating chamber situated on the other side of the piston increases. This will force the liquid in the first-mentioned operating chamber through the conduit 15 into the operating chamber of the operating cylinder 8, which chamber adjoins the supporting arm 2. As a result, the piston in the operating cylinder 8 is urged toward the load supporting portion 4 which is thereby swung about the pivot axis 5. This will reduce the volume of the operating chamber of the cylinder 8 that adjoins the load supporting portion 4, and the liquid in this operating chamber is urged through the conduit 14 to the operating chamber of the cylinder that adjoins the frame member 1.

Because of the dimensions and the location of the operating cylinders 8 and 9 the load supporting portion 4 will always occupy the same angular position relative to the ground irrespective of whether the supporting arm 2 is swung upwardly or downwardly relative to the pivot point 3 on the frame member 1. The horizontal loading plate 6 will thus always occupy its horizontal position.

Different dimensions of the operating cylinders 8 and 9 can be compensated for by different pressure ratios in the conduits 14 and 15. However, the piston surfaces in two interconnected operating chambers in the cylinders 8 and 9 shall always be equally large. In the embodiment illustrated this is realized in that the piston in the cylinder 9 is provided with an extension 17 shaped like a piston rod and having twice as large an area as the piston rod proper. In another embodiment the pistons in both operating cylinders 8 and 9 may be provided with piston rod-shaped extensions 17 which in that case shall have the same area as the piston rod proper.

A lifting cylinder 16 is adapted to impart to the supporting arm 2 the desired pivotment thereof.

The above embodiment of the invention was described for purposes of illustration rather than limitation. All possible variations and modifications of the invention are understood as being included within the scope of the appended claims.

What I claim and desire to secure by Letters Patent is:

1. A loading gear comprising a frame, a supporting arm pivotally mounted at one end on said frame, a load supporting member pivoted to the other end of said supporting arm, a first cylinder pivotally mounted on said supporting arm, a first piston movable in said first cylinder, a first piston rod for said piston pivotally connected at its free end to said load supporting member, said first piston and first cylinder forming one side of a first triangle whose corners are located at the pivoted points of said first piston rod, cylinder, and said load supporting member, a second cylinder pivotally mounted on said frame, a second piston movable in said second cylinder, a second piston rod for said second piston having its free end pivotally connected to said supporting arm, said second cylinder and said second piston rod forming one side of a second triangle whose corners are located at the pivoted points of said second piston rod, said second cylinder and said supporting arm, said first and second pistons and cylinders being double acting and having operating chambers communicating in pairs via direct conduits so that said load supporting member is pivoted when said supporting arm is pivoted, said operating chambers in said first and second cylinders above said first and second pistons communicating through said direct conduits with those operating chambers in said first and second cylinders below said pistons, said communicating operating chambers having proportional effective areas and said first and second triangles having proportional sides whereby said pistons will move uniformly in relation to said cylinders When said supporting arm is pivoted so that said load supporting member during said pivoting movement will move parallel to itself.

2. A loading gear as claimed in claim 1 wherein one of said pistons is provided with a piston rod-shaped extension below the piston for providing proportional effective areas in the operating chambers.

References Cited by the Examiner UNITED STATES PATENTS Osgood.

Brock 6054.5 X Hemings 6097 Mindrum -21414O ROBERT R. BUNEVICH, Examiner.

Claims

1. A LOADING GEAR COMPRISING A FRAME, A SUPPORTING ARM PIVOTALLY MOUNTED AT ONE END ON SAID FRAME, A LOAD SUPPORTING MEMBER PIVOTED TO THE OTHER END OF SAID SUPPORTING ARM, A FIRST CYLINDER PIVOTALLY MOUNTED ON SAID SUPPORTING ARM, A FIRST PISTON MOVABLE IN SAID FIRST CYLINDER, A FIRST PISTON ROD FOR SAID PISTON PIVOTALLY CONNECTED AT ITS FREE END TO SAID LOAD SUPPORTING MEMBER, SAID FIRST PISTON AND FIRST CYLINDER FORMING ONE SIDE OF A FRIST TRIANGLE WHOSE CORNERS ARE LOCATED AT THE PIVOTATED POINTS OF SAID FIRST PISTON ROD, CYLINDER, AND SAID LOAD SUPPORTING MEMBER, A SECOND CYLINDER PIVOTALLY MOUNTED ON SAID FRAME, A SECOND PISTON MOVABLE IN SAID SECOND CYLINDER, A SECOND PISTON ROD FOR SAID SECOND PISTON HAVING ITS FREE END PIVOTALLY CONNECTED TO SAID SUPPORTING ARM, SAID SECOND CYLINDER AND SAID SECOND PISTON ROD FORMING ONE SIDE OF A SECOND TRIANGLE WHOSE CORNERS ARE LOCATED AT THE PIVOTED POINTS OF SAID SECON PISTON ROD, SAID SECOND CYLINDER AND SAID SUPPORTING ARM, SAID FIRST AND SECOND PISTONS AND CYLINDERS BEING DOUBLE ACTING AND HAVING OPERATING CHAMBERS COMMUNICATING IN PAIRS VIA DIRECT CONDUITS SO THAT SAID LOAD SUPPORTING MEMBER IS PIVOTED WHEN SAID SUPPORTING ARM IS PIVOTED, SAID OPERATING CHAMBERS IN SAID FIRST AND SECOND CYLINDERS ABOVE SAID FIRST AND SECOND PISTONS COMMUNICATING THROUGH SAID DIRECT CONDUITS WITH THOSE OPERATING CHAMBERS IN SAID FIRST AND SECOND CYLINDERS BELOW SAID PISTONS, SAID COMMUNICATING OPERATING CHAMBERS HAVING PROPORTIONAL EFFECTIVE AREAS AND SAID FIRST AND SECOND TRIANGLES HAVING PROPORTIONAL SIDES WHEREBY SAID PISTONS WILL MOVE UNIFORMALY IN RELATION TO SAID CYLINDERS WHEN SAID SUPPORTING ARM IS PIVOTED SO THAT SAID LOAD SUPPORTING MEMBER DURING SAID PIVOTING MOVEMENT WILL MOVE PARALLEL TO ITSELF.