US1720980A

US1720980A - Lifting device

Info

Publication number: US1720980A
Application number: US291223A
Authority: US
Inventors: Charles L Trapp
Original assignee: Globe Machinery & Supply Compa
Current assignee: Globe Machinery & Supply Co; Globe Machinery & Supply Compa
Priority date: 1928-07-09
Filing date: 1928-07-09
Publication date: 1929-07-16
Anticipated expiration: 1946-07-16

Description

C. L. TRAPP LIFTING DEVICE July 16, 1929.

Filed July 9, 1928 Ch qrl es L. Tfa o o awvem io'o Patented July. 16, 1929.

UNITED STATES I'PATENT OFFICE.

CHARLES L. TBAPP, 0F OMAHA, NEBRASKA, ASSIGNOR TO GLOBE MACHINERY & SUP- IE'LY COMPANY, OF DES MOINES, IOWA, A CORFORATION.

LIFTING nnvrcn,

Application filed July. 9,

My invention relates to that class of lifting devices, called pneumatic and hydraulic, which are commonly employed. for raising automobiles, platforms or other heavy objects, from lower to higher positions, and which individually comprise a container or reservoir for oil orlike rigid fluid, means for forcing-air or other elastic'fluid into the container, a casing, or cylinder,connected with thecontainer, and a piston which is driven by v oil forced from the container into the casing by air pressure. It is the main object of .the

invention to avoid, in devices of this descrip tion, allleakage of oil between the oil container and the casing; to prevent the siphonageof oil from the reservoir into the casing; to facilitate the removal of oil from the reservoir, as occasion may require; and to attain compactness and simplicity of construction. T o accomplish these results, I incorporate in my improved lifting device, as parts thereof, a casing which may be integrally united with he top of the oil reservoir, an intercommu- "nicating oil pipe-between the casing and the interior of the .oil reservoir, and asupply and discharge oil pipe extending from outside into the interior of the oil reservoir.

In said drawings, which illustrate the best manner in which I have contemplated applying the principles of the invention, Fig. 1 is a plan view of a lifting device which is constructed in accordance with these principles. Fig. 2 is an axial section on the section line of Fig. 1.- Fig. 3 is an axial section of the same on the same section line, but with the piston in a lifted position.

In these drawings the oil reservoir, which is a closed metallic tank of general cylin dri cal form, is denoted by the numeral 1. The

cylindrical casing 2 iswelded to the head 3 of this reservoir, and is thereby united with the tank coaxially, immediately, integrally, and in a manner to preclude leakage. This ca sing has at the top an annularhead l, which is held in place thereon by the screw studs 5. The piston, which is coaxial with the casing, comprises the hollow cylindrical rod, or stem 7, having the peripheral stop ring 20 and the head 8. The piston proper 9 closes the lower end of the rod or stem 7 and fits snugly in the cylinder 2 to travel therein. The packing 10, which contacts with the inside of the cylinder 2 is clamped to the piston 9 by the screws 11 and the follower 12. The packing is preferably of the cup leather type with 1928. Serial No. 291,223.

the reservoir 1, I employ .any convenient means, including, and sufficiently represented by, the vertical pipe 13, which is joined to the reservoir head 3 at the coupling 14. For

the purpose of supplying the oil reservoir with oil, and of emptying or refilling the same,

as occasion or convenience may require, the vertical oil pipe 15 is joined to the reservoir head 3 at the coupling 16 and extends upward to the ground level or to any other desired height, where it is closed by the removable screw cap 17. This pipe has a continuation 6, which extends. within the reservoir from the coupling at 16 to a point near the bottom or floor of the reservoir. The open and vertical pipe 18, which is coupled to the middle of the reservoir head 3 at 19, and which extendsnearly to the bottom of the reservoir, affords the only intercommunieation be tween the reservoir and the casing 2.

Operatively the reservoir may be supplied with oil 21 through the

pipe

15 and 6, which s afterward stopped by the cap 17, as shown in Fig. 2. By the pressure of air forced into the reservoir through pipe 13 oil is driven continuously through pipe 18 into the casing, where it lifts the piston from the position shown in Fig. 2, toward or to that shown -in Fig. 3, where itis stopped by ring 20 in contact with head 1 of the casing. On relief of the air pressure, as by the cock 22, the piston will return gradually to its original position. T he operative oil supply may then be removed from the reservoir at pleasure through the

pipe

6 and 15 by removing the cap 17 and by admitting air under pressure through pipe 13.

It will be noted that the piston rod or stem 7 is of smaller external diameter than the internal diameter of the cylinder 2 and that the member 4 serves as a guide for the piston rod.

The piston can be removed and oil supplied directly to the reservoir through the cylin- My lifting device is intended primarily for use in oil service stations for raising and rotating automobiles in orde to afford access to their under parts for oiling and greasing. The cylinder and reservoir are located in a suitable pit in the floor or in the ground.

In some instances, there is arranged between a tank located above the lower end of the cylinder and the cylinder a pipe extenddesirable.

By placing the oil reservoir wholly below the cylinder and piston, I have provided a means whereby, if any leakage occurs, as for instance by seepage past the cup packing or otherwise, such oil will gravitate back into the oil reservoir, and this result obviously cannot be attained by devices of this character in which the oil reservoir is above some part of the piston or cylinder.

It will be observed that I have provided a very compact unit for the purposes of sh1pping and installation. It is also to be noted that the oil is kept deep in the ground when the device is not in use. This avoids the danger of freezing 'or congealing it. It should also be noted that the piston rod never contains oil and therefore that there isno oil above the ground surface to congeal at any time in the operation of the device.

The piston rod being of smaller diameter than the interior of the cylindernever gathers any oil which might form a frozen film above the cylinder.

I claim as my invention 1. The combination of an upright cylinder, a hollow piston rod vertically movable in the cylinder and closed against the admission of oil at all times, a piston at the lower end of the piston rod, a cup packing carried by the piston and having its flange extended downwardly, an oil reservoir supported below the lower end of the cylinder and having a capacity slightly greater than that of the cyl-. inder below the piston when the piston is fully extended, a pipe leading from the bottom of the oil reservoir upwardly and capable of draining substantially all of the oil from the cylinder when the piston is down and leaving an air chamber above the oil, and means for introducing air under pressure to the top of the oil reservoir.

2. The combination of an upright cylinder, a piston vertically movable in the cylinder, a cup packing with its flange extended downwardly carried by the piston, a hollow piston rod extended upwardly from the piston, a guide for the upper portion of the piston rod, the hollow piston rod being closed against the admission of oil at all times, an oil reservoir supported below the cylinder, a pipe extending from the bottom of the oil reservoir upwardly and communicating with the lower end of the cylinder, and means for supplying air under pressure to the top of the oil reservoir.

3. The combination of an upright cylinder, a piston vertically movable in the cylinder, 9. cup packing with its flange extended downwardly-carried by the piston, a piston rod extended upwardly from the piston, a guide for the upper portion of the piston rod, the piston rod being closed against the admission of oil at all times, the piston rod above the pistonand the interior of the cylinder being spaced apart so that a film of oil on the interior of the cylinder cannot be transmitted to the piston rod, an oil reservoir supported below the cylinder, a pipe extending from the bottom of the oil reservoir upwardly and communicating with the lower end of the cylinder, and means for supplying air under pressure to the top of the oil reservoir.

4:. The combinationot' an upright cylinder, a piston vertically movable in the cylinder, a cup packing with its flange extended downwardly carried by the piston, a piston rod pressure to the top of the oil reservoir, and a stop device attached to the piston rod in said space between the piston rod and the cylinder, to engage said guide.

5. In a lifting device, the combination of an upright cylinder, a piston vertically reciprocable in the cylinder carrying a packing between it and the cylinder, a piston rod extending upwardly from the piston, an oil reservoir fixed to and forming a unitary structure with'the lower end of the cylinder below the lowermost position of the movement of the piston, a pipe extending from near the bottom of the oil reservoir upwardly and communicating with the lower end of the cylinder below the piston, and means for supplying compressed air to the top of the oil reservoir.

. 6. The combination of an upright cylinder, a hollow piston rod vertically movable in the cylinder, 'a piston at the lower end of the piston rod, apacking carried by the piston, an oil reservoir supported below the lower end of the cylinder, a pipe leading from the bottom of the oil reservoir upwardlyand capable of draining substantially all of the 'oil from the cylinder when the piston is down, and means for introducing air under pressure to the top of the oil reservoir.

Witness my signature at Omaha, Nebraska, June 30, 1928.

CHARLES L. TRAPP.

extended upwardly from the piston, a guide