US3481858A

US3481858A - Vacuum operated work-holding electrical contact device for electrolytic treatment

Info

Publication number: US3481858A
Application number: US618396A
Authority: US
Inventors: Howard A Fromson
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-02-24
Filing date: 1967-02-24
Publication date: 1969-12-02
Anticipated expiration: 1986-12-02

Description

Dec. 2. 1969 H. A. F'ROMSON 3,481,358 VACUUM OPERATED WORK-HOLDING ELECTRICAL CONTACT DEVICE FOR ELECTROLYTIC TREATMENT Filed Feb. 24, 1967 2 Sheets-Sheet 1 Dec. 2, 1969 H. A. FROMSON 3,481,858

VACUUM OPERATED WORK-HOLDING ELECTR L CONTACT DEVICE FOR ELECTROLYTIC TREA NT Filed Feb. 24, 1967 2 Sheets-Sheet 2 ///////////////Z T i W l N VENTO R A/i AWDA fkomm United States Patent O 3,481,858 VACUUM OPERATED WORK-HOLDING ELECTRICAL CONTACT DEVICE FOR ELECTROLYTIC TREATMENT Howard A. Fromson, Rogues Ridge Road, Weston, Conn. 06880 Filed Feb. 24, 1967, Ser. No. 618,396 Int. Cl. C231) 5/70 US. Cl. 204-297 8 Claims ABSTRACT OF THE DISCLOSURE An apparatus for simultaneously holding workpieces suspended in an electrolytic bath and conducting an electric current to the workpieces. Suction cups flexibly suspended from an overhead vacuum manifold grip and support the workpieces, and draw them into contact with a valve mechanism inside the cups which serves to open a vacuum line to the manifold and also to make electrical contact between the apparatus and the workpieces.

BACKGROUND OF THE INVENTION This invention relates to apparatus to be used in the electrolytic surface treatment of workpieces. More particularly it relates to a suspension device which is adapted to move articles destined for treatment into a bath of electrolyte and to hold said articles within said bath While current is supplied to them and electrolysis progresses.

Electrolytic surface treatment of articles, such as plating or anodizing, requires that the article be suspended within a bath of electrolyte While an electric current is passed through the article to the electrolyte. In the past various suspension devices have been used, with the article usually held by a metal clamp or gripper. Current is supplied to the article from the clamp. Such devices have the disadvantage that exposed metallic surfaces of the clamps tend to be affected by the electrolyte and the current, with the result that the clamp is gradually either eroded or plated with undesirable metal. In addition, the clamps involved are often adapted to hold only certain shapes of articles, so that in a commercial operation where successive batches of articles of markedly different shape may be treated, it is necessary to have a large variety of clamps and to lose time substituting one type for another between batches.

Clamps of the type mentioned above may also be relatively slow and difiicult to attach to the article being treated, and perhaps will tend to mar its finish. Finally, in some cases it is hard to obtain a satisfactory purchase on the article to be held because the shape thereof is unsuited to clamping.

It is known to suspend a plurality of articles to be treated within a bath from an overhead pipe, clamps such as those described receiving electric current from conductors within the pipe. Such devices have the disadvantages discussed with regard to clamps. They also have exposed electrical joints between the clamps and the conductor which are subject to corrosion.

It is also well known in the field of lifting devices to grip articles to be supported by means of suction cups.

SUMMARY A movable elongated manifold of pipe-like construction is provided, with an internal vacuum chamber therein and an internal bus bar adapted to be connected with an outside source of current. Flexible hollow vacuum hoses depend from the manifold and internal conductors within the hoses are connected to the bus bar. Each vacuum hose terminates at its lower end in a suction cup structure, the neck of the cup being internally fitted with 3,481,858 Patented Dec. 2, 1969 a combination valve and electrical contact structure. The valve has a valve stem which projects into the hollow of the suction cup and which is depressed if the cup is pressed against a workpiece; the stem when so depressed allows communication between the space within the suction cup and the vacuum manifold, by way of the vacuum hose. The resulting vacuum within the suction cup causes it to adhere to the workpiece for support thereof. In addition, the valve stem is connected to the bus bar by means of the internal conductors within the vacuum hoses, so that current may flow through the valve stem to the workpiece. Removal of the suction cups from the .workpiece allows the valve to close in order to maintain the vacuum within the manifold.

The invention achieves a good supporting grip on workpieces of various shapes. Workpieces are easily attached and the required electrical connection automatically occurs. Marring of the surface of the workkpiece is prevented. The metallic conducting attachments are shielded from attack by the electrolyte, insuring a continued current fiow and preventing their destruction. The need for large numbers of accessory clamps is obviated, so that more versatility is achieved at less cost. The device is relatively light in weight and tough compared with devices employing metal clamps, which may become bent or broken if abused.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial sectional view of a device embodying my invention; and

FIG. 2 is an enlarged sectional view of a suction cup and related valve structure which are part of the device of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT A vacuum manifold 10 is comprised of a length of pipe 11 with end caps 12 and 13 attached thereto by screw threads. Lifting rings 14 are attached to the pipe and are adapted to be engaged by the books 15 of any convenient lifting device (not shown). The space within the vacuum manifold may be evacuated to form a partial vacuum therein, any convenient pump being employed and the removed gas leaving the vacuum manifold through a flexible suction hose 16. The suction hose is a push fit over a tapered spout 17 which projects from a valve 18 which is mounted on a short length of pipe 19 which in turn projects from pipe 11. By means of the valve a vacuum once drawn in vacuum manifold 11 may be retained while the suction hose is removed.

At spaced intervals along the underside of the vacuum manifold there are provided outwardly projecting nipples 20. A length of support hose 21 is attached to each nipple by a hose clamp 22. Each such support hose is adapted to sustain a partial vacuum without collapsing and extends downward to a suction cup 23. When in use the suction cup is adhered to a workpiece 24 and is suspended with the workpiece within a tank 25 containing an electrolyte 26.

As may best be seen in FIG. 2, the suction cup 23 is provided with a valve to regulate flow through the support hose 21. This structure comprises a tubular metal shell 27 to which the rubber cup 28 is bonded. The upper end of the shell fits within support hose 21 and these elements are squeezed together by hose clamp 29. The central portion of shell 27 between the hose and the cup is wrapped with rubber tape 30.

Press fitted within shell 27 is metal valve casing 31 which is of generally tubular structure. The lower end of the valve casing is partially closed by an end plate 32 having surfaces defining a central bore therethrough and a conical valve seat 33. The upper end of the valve casing is also partially closed by an inwardly extending lip 34. Within the valve casing there is located a springloaded valve 35 comprised of a valve guide rod 36 and a valve body 37. The valve guide rod is loosely fitted Within lip 34 and the central bore through plate 32. A conical valve face 38 on the valve body is biased into sealing contact with the valve seat by helical spring 39 when the suction cup is not attached to a workpiece. The force of spring 39 is suflicient under such conditions to seal the passage through the valve casing against the differential in pressure between the atmosphere and the inside of the vacuum manifold. When the suction cup is pressed against a workpiece, however, as shown in FIG. 2, the tip 40 of valve guide rod 36 contacts the workpiece and is driven upward as shown. This opens the valve and allows the space enclosed by the cup to be evacuated through support hose 21. The subsequent collapse of the cup against the workpiece keeps the valve open and enables the cup to maintain its grip in spite of possible leakage around its rim.

As a convenience in breaking the grip of the suction cup on the workpiece the edge of the cup is provided with an integral tab 41 which may be lifted with the fingers.

A cord 42 extends from the hose clamp on the suction cup up and around the vacuum manifold. The cord sup ports the cup at any convenient distance below the manifold, and may be changed in length to accommodate different arrangements of workpiece.

The required electric current is conducted to the workpiece through internal wires. An internal bus bar 43 extends the length of the vacuum manifold. One end thereof is supported in a socket 44 of hard rubber, plastic, or other insulating material which is in turn fastened to end cap 12. The other end of the bus bar projects outward through end cap 13 and is connected to a flexible cable 45 bringing current from any convenient source. The bus bar is insulated from the cap 13 by insulating sleeves 49 and 50. These are respectively mounted Within nipple 47 and cap 48. A rubber O-ring 46 is squeezed between the flanges of the insulating sleeves by tightening cap 48 and thus provides the necessary vacuum-tight seal around the bus bar.

At intervals along the length of the bus bar there are located terminals 51. To each terminal is attached a flexible copper wire 52 which extends downward through a nipple 20 to the inside of the support hose 21. Contact between the wire and the nipple may be prevented by insulation on the wire or, as shown, by an insulating spider 53.

The lower end of the flexible wire 52 is soldered to sleeve 54, and the sleeve is in turn clamped to the upper end of the valve guide rod 36 by set screw 55. By this means current is conducted through the tip of the valve rod to the workpiece 24.

The device as described may be suspended in any desired location while a partial vacuum is drawn within the vacuum manifold and workpieces are attached to the suction cups. The latter operation is easily accomplished, the operator need only press the cup against the workpiece. The valve will then be opened and held open as the cup collapses against the workpiece. Electrical contact is automatically achieved. The device with workpieces attached may be transported to any number of tanks as desired. Once the workpieces are attached the valve 18 may be closed and the device freed from suction hose 16 for substantial periods of time. During electrolytic treatment the electrolyte cannot contact the valve mechanism and electric connection with the workpiece, and these parts are thereby shielded from electrolytic attack.

While the suction cup disclosed herein is the ordinary flexible rubber cup of circular outline, it will be understood that the term suction cup as used in the following claims is intended to indicate any device which may be adhered to a workpiece by the force of the ambient fluid pressure when an area of reduced pressure is created between said device and the surface of the workpiece. In addition, the term fluid is intended to refer to both gases and liquids.

The following is claimed:

1. In a device for holding a workpiece comprising a suction cup adapted to cover and cohere to a selected area of a workpiece under the influence of external fluid pressure, a conduit communicating with the space between the suction cup and the selected area of a workpiece when the suction cup is in contact with the workpiece and defining a passageway for the removal of fluid from said space; a valve in said conduit; biasing means for holding the valve in a closed position and thereby blocking said passageway when the suction cup is not cohered to a workpiece; workpiece contact actuated means for holding said valve in an open position in which it does not block the passage while the suction cup is cohered to the workpiece, the improvement wherein said workpiece contact actuated means is an electrical contact.

2. The device of claim 1 comprising means for withdrawing fluid from the space between the suction cup and a workpiece contacted by said suction cup after the establishment of a fluid-tight seal between the suction cup and the workpiece.

3. The device of claim 1 wherein the valve comprises a member arranged to contact and be moved relative to the suction cup by the workpiece as the suction cup is pressed against the workpiece and to move the valve from the closed to the open position as a result of said motion.

4. The device of claim 3 wherein the member serves as the electrical contact.

5. In a device for holding a workpiece comprising a suction cup adapted to cover and cohere to a selected area of a workpiece under the influence of external fluid pressure, the improvement comprising a conduit adapted to communicate with the space between the suction cup and the selected area of the workpiece when the suction cup is in contact with a selected area of the workpiece and to provide a passage for the removal of fluid from said space; a valve casing in the conduit blocking said conduit; a surface defining a central bore in the valve casing; surfaces on the central bore defining a valve seat; a valve guide rod projecting through the central bore into the space between the suction cup and the workpiece when the suction cup is cohered to a workpiece, said valve guide being movable inward from a first to a second position by pressure of the workpiece against an outer end of the valve guide rod; an electrical conductor connected to the valve guide rod and adapted for connection with a source of electrical current; a valve body on the valve guide rod; a valve face on the valve body contacting the valve seat and blocking the central bore when the valve guide rod is in the first position and spaced from the valve seat when the valve guide rod is in the second position; and a spring biasing the valve guide rod toward the first position.

6. The device of claim 5 comprising means for supporting the suction cup in a desired position and thereby at least :partially supporting the weight of a workpiece attached to said suction cup in a desired position.

7. The device of claim 6 comprising a vacuum manifold communicating with the conduit; a bus bar within the vacuum manifold; and means for connecting the electrical conductor to the bus bar.

8. A device for holding a workpiece comprising:

(a) an elongated vacuum manifold having a long axis;

(b) means for suspending the vacuum manifold with the long axis thereof in a nonvertical position;

(c) a bus bar within the vacuum manifold extending the length of the vacuum manifold;

(d) means for transmitting an electric current to the bus bar from the outside of the vacuum manifold;

(e) a plurality of vacuum conduits extending downward from the vacuum manifold at spaced intervals along the length thereof, said conduits communicating with the space within the vacuum manifold;

(f) a suction cup at the lower end of each vacuum conduit;

(g) surfaces defining a fluid passageway between the space within each suction cup and the associated vacuum conduit;

(h) a valve occluding each fluid passageway when said valve is in a closed position;

(i) a contact connected to the valve adapted to contact the workpiece and, when in such contact, to move the valve from the closed to an open position;

(j) an electric contact within the suction cup adapted to make electrical contact with the workpiece;

(k) a conductor extending within each vacuum conduit from each electric contact to the bus bar.

6 References Cited UNITED STATES PATENTS OTHER REFERENCES A. P. C. Publication, Ser. No. 290,026, Weiner, published July 1943.

IBM Technical Disclosure Bulletin, vol. 6, No. 7,

December 1963.

JOHN H. MACK, Primary Examiner D. R. JORDAN, Assistant Examiner US. Cl. X.R.