US2891433A

US2891433A - Apparatus for removing coatings

Info

Publication number: US2891433A
Application number: US607013A
Authority: US
Inventors: Ackermann Walter
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1956-08-30
Filing date: 1956-08-30
Publication date: 1959-06-23
Anticipated expiration: 1976-06-23

Description

June 1959 w. ACKERMANN APPARATUS FOR REMOVING commas Filed Aug. so. 1956 INVENTOR.

WA LTER AEKER'MANN United. States Patent 2,891,433- APPARATUS FOR REMOVING GGA'IIIIGS Lyndhurst, N.J., assignor to Radio Walter Ackermann,

a corporation of Delaware 1 This? invention relates tov improved method andr apparams for removingfriable, coatings from support members and, particularly although not exclusively, for removing friable insulating coatingsfrom wires employed as heaterelements in electron discharge tubes; whereby the electrical connection of these wires to other elements is facilitated.

One type of apparatus for removing friable insulating coatings from electrical wires utilizes a pair of hammers which are brought into contact with diametrically opposed portions of the coated wire placed between them. The impact of the hammers crushes the insulation which falls away from the wire to leave a bare portion. Although such apparatus does a comparatively eificient job, particles of the insulation may remain on the wire and may prevent the formation of good soldered or welded joints.

The objects of the present invention concern the provision of improved method and apparatus for removing friable insulating coatings from wires or other support members.

In general, the method of the invention comprises applying a crushing force to a portion of the insulation of a wire and then, with the crushing force still applied, rotating the wire to expose all of the periphery of the coating to the crushing force.

Apparatus embodying the principles of the invention comprises a pair of hammers having opposed crushing surfaces. Means are provided for bringing the hammers together in axial alignment so that they crush -a portion of the insulating coating of a wire which is positioned between them. Means are also provided for vibrating at least one of the hammers while the hammers are in contact with the wire so that other portions of the insulating coating are crushed and may be readily removed.

The invention is described in greater detail by reference to the drawing wherein:

Fig. 1 is a plan view of apparaus embodying the principles of the invention; and,

Fig. 2 is an elevational view of the apparatus of Fig. 1.

The apparatus and method of the invention are particularly useful in removing selected portions of the insulating coating of an electron tube heater wire to provide bare portions of wire which may be welded or soldered to suitable leads within an electron tube. Such a wire is cylindrical in form and comprises a metal core 12 having an insulating coating 14, of for example, aluminum oxide.

Apparatus 16 for removing portions of the insulating coating from the wire 10 includes a pair of

hammers

18 and 20 made of tungsten carbide or other material suitable for the intended purpose. The

hammers

18 and 20 have planar crushing

surfaces

22 and 24, respectively, and the hammers are adapted to be axially aligned with the crushing surfaces parallel and face to face when the apparatus is in operation.

The hammer 18 is secured between a pair of plates 2,891,433 Patented June-23,1 1 959- 262and: 28iwitli' a lip 29 formed ontthe hammerirestingt oma. shoulder 30 formed in the plate 28;. The:

plates

26 and 28 are held together by bolts 31rtorform a ham men assembly-which: itself is secured to a: support arm 321bya bolt34 secured at its free end-to 'asuitable'suw poi-t member 36'; The'free end of thesupportarm is also :provided with: gear" teeth: 38 which mesh with a gear rackz40iand1the: gear rack .40 is connected'to a piston rod 42 ofia conventional'double-acting air cylinder 44. The air cylinder has.

air inlet pipes

46 and 48" which are con nected to a source. of air"(not shown);

Thehammer 20 is secured between a pair of-plates? 50 andSZ-with a lip-S3' form'ed'on the hammen resting on: a shoulder 54 formed on the plate 52: The' plates 50 and 52: are helds together: by bolts: 55 tofbrm: a hammer as sembly; which itself is=secured to a support arm 561' by a: bolt 58:- Tliepressure betweenthe platesi50: and 52 is suflicient to: hold the: hammer securely: while: allow ing it to moverlaterally; between: therplatesaasz-showrt by the arrows 59 in Fig. 1. The support arm 56 is secured to the support member 36 at its free end which is provided with gear teeth 60 which mesh with the gear rack 40.

According to the invention, means are provided for vibrating or oscillating one or both of the

hammers

18 and 20. One such arrangement is shown for vibrating the hammer 20 and includes a lateral projecting portion 62 from the hammer, the projecting portion being secured to one end of an armature 64 the other end of which is suitably secured to the housing of a relay coil 66. The armature 64 is spaced from the

plates

50 and 52 and its path of vibration is limited by

stops

68 and 70 on the coil 66 and plate 50, respectively. The coil 66 is secured to the support arm 36 by a bracket 72 and it is electrically connected through a switch 74 to a source 76 of alternating voltage.

In operation of the apparatus 16, the wire 10 is positioned between the

hammers

18 and 20 which are open and spaced apart. In this position of the hammers, air is flowing through, for example, the inlet pipe 46 into the air cylinder 44 and the piston rod 42 is held in its most forward position so that the support arms and hammers are remote from each other. The air flow to the air cylinder is then switched into the inlet pipe 48 and the piston rod is driven to its most rearward position. As the piston rod moves, the

support arms

32 and 56 rotate toward each other and the hammers come together in axial alignment and the crushing

surfaces

22 and 24 thereof contact diametrically opposed portions of the coating 14 on the wire 10 with sufiicient force to crush these portions of the coating. With the hammers thus held against the wire, the switch 74 is closed and the relay coil 66 is energized and the armature 64 is vibrated. At the same time, the hammer 20 vibrates or oscillates in a path transverse to the longitudinal axis of the wire 10 and its crushing surface 22 moves back and forth substantially parallel to the crushing surface 24 of the hammer 18 which is held stationary. This relative movement between the crushing surfaces of the hammers causes the wire 10 to rotate between the hammers as shown by the arrow and a complete annular portion of the coating is crushed and falls away from the core 12 to provide a bare leg 78 (Fig. 2).

Air flow to the air cylinder 44 is then switched into the inlet pipe 46, the piston rod 40 is driven forward and the

support arms

32 and 56 and the

hammers

18 and 20 are driven apart. The wire 10 is then removed and ready to have an electrical connection made to the bare portion formed by the crushing operation.

What is claimed is:

1. Apparatus for removing a friable coating from a structure consisting of a core having said coating thereon comprising a pair of relatively movable hammers, means for bringing said hammers into contact with said coating whereby said hammers crush a portion of said coating when said structure is positioned between said hammers, and means for vibrating one of said hammers whereby other portions of said coating are crushed between said hammers.

2. Apparatus for removing a friable coating from a structure consisting of a core having said coating thereon comprising a pair of relatively movable hammers, means for bringing said hammers into axial alignment and into contact with said structure when said structure is positioned between said hammers, and means for os cillating one of said hammers in a path transverse to the longitudinal axis of said structure.

3. Apparatus for removing a friable coating from a structure consisting of a core having said coating thereon, comprising a pair of relatively movable hammers having planar crushing surfaces, means for bringing said hammers into axial alignment with said crushing sur- 20 faces face to face and parallel to each other, and means for oscillating one of said hammers in a path parallel to the crushing surface of the other hammer.

4. Apparatus for removing a friable coating from a cylindrical structure consisting of a core having said coating thereon comprising a pair of relatively movable hammers, means for bringing said hammers into axial alignment and into contact with diametrically opposed portions of said coating when said structure is positioned between said hammers whereby said portions of said coating are crushed, and means for vibrating one of said hammers in a path transverse to the longitudinal axis of said structure whereby an annular portion of said coating is crushed.

References Cited in the file of this patent UNITED STATES PATENTS 878,493 Barnes Feb. 11, 1908 1,726,623 Hollnagel Sept. 3, 1929 1,831,115 Holmes Nov. 10, 1931 1,929,921 Gaylord Oct. 10, 1933 2,037,421 Littler Apr. 14, 1936 FOREIGN PATENTS 481,662 Great Britain Mar. 16, 1938