US 3169791 A
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Description (OCR text may contain errors)
Feb, 16, 1965 G TWACHTMAN I MAGNETIC RETRIEVERS Filed Jan. 18. 1962 Press EFM s fawn? mam 6 t Inventor:
Godfrey Tvmchtmon tied and the cost of production materially reduced.
United rates Patent filice 3,169,791 Patented Feb. 16, 1965 MAGNETIC RETRIEVERS Godfrey 'Iwaehtrnan, 618 N, Deiaware, Independence, Mo.
Filed Jan, 18, 1962, Ser. No. 167,1]ld ll tClairn, (Cl. 294-=-t5.5)
This invention relates to new and useful improvements in magnetic retrievers for use in picking up objects of magnetically attractable metal from poorly ac cessible locations, and in particular the invention relates to certain improvements in the retriever disclosed in United States Patent No. 2,993,723, issued July 25, 1961, jointly to Godfrey Twachtman and John A Ware.
When placing the retriever in accordance with the aforementioned patent in production I found that the same lends itself to certain structural modifications, particularly from the standpoint of assembly of the magnet and shaft, whereby manufacture is considerably simpli- It is, therefore, the principal object of the present invention to provide a magnetic retriever wherein such improvements, are embodied.
Other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawing, wherein like characters of reference are used to designate like parts, and wherein:
FIGURE 1 is an elevational view of a magnetic retriever in accordance with the present invention;
FIGURE 2 is an enlarged, fragmentary longitudinal sectional view taken substantially in the plane of the line 22 in FIGURE 1;
FIGURE 3 is a cross-sectional view, taken substantially in the plane of the line 33 in FIGURE 2; and
FIGURE 4 is a cross-sectional view, taken substantially in the plane of the line 4- t in FIGURE 2.
Referring now to the accompanying drawing in detail, the magnetic retriever in accordance with the present invention is designated generally by the reference numeral and embodies in its constructiona resiliently flexible, slender shaft 11 which is normally straight but may be bent to any desired form during use of the tool. The shaft 11 consists of a core in the form of a closely wound helical spring 12 which is'completely covered by a tubular jacket 13 of synthetic plastic material, whereby to protect the spring against dirt, moisture, and the like.
One end portion of the spring 12 projects outwardly from the jacket 13 and is press-fitted into one end portion of a tubular sleeve or casing 14, which is preferably although not necessarily made of brass or some other non-magnetizable material. The adjacent endportion of the jacket 13 is stretched and tightly fitted over the sleeve or casing 14, as indicated at 15 so as to prevent access of moisture, et cetera, to the interior of the sleeve and spring therein.
A cylindrical permanent magnet 16 is press-fitted into the other end portion of the sleeve 14 and is permitted to project outwardly therefrom to some extent as shown, the inner end of the magnet preferably being spaced from the adjacent end of the spring 112; to provide an air gap 17.
It will be apparent from the foregoing that the present invention utilizes a simple tubular sleeve 14 for connection of the magnet 16 to the spring 12 of the shaft ill, so that the use of aspecially'machined housing such as exists in the aforementioned patent is not required. Moreover, the spring and the magnet are of the same diameter so that they may both be press-fitted into the simple tubular jacket without the use of a keeper pin to hold the magnet in place. Also, the pole piece of the aforementioned patent is eliminated, thus leaving the portion of the magnet which projects from the sleeve to come in direct contact with the work.
The free end of the shaft 11 is provided with an I- shaped finger piece 118 which may either be separately formed and secured to the spring 12, or be constituted by forming the last few convolutions of the spring into the finger piece, as desired.
While in the foregoing there has been described and shown the preferred embodiment of the invention, various modifications may become apparent to those skilled in the art to which the invention relates. Accordingly, it is not desired to limit the invention to this disclosure and various modifications and equivalents may be resorted to, falling within the spirit and scope of the invention as claimed.
What is claimed as new is:
In a magnetic retriever, the combination of a straight tubular sleeve of non-magnetizable metallic material having a bore of a constant diameter open at both ends thereof, a tightly wound helical spring having one end portion thereof press-fitted into and tightly held in one end portion of the bore of said sleeve, a cylindrical permanent magnet of the same diameter as said spring pressfitted into and firmly held in the other end portion of the bore of said sleeve and projecting outwardly therefrom, the inner end of said magnet in said sleeve being spaced longitudinally from the adjacent end of said spring to provide an air gap therebetween, and a tubular. plastic jacket enclosing said spring, an end portion of said jacket being radially stretched and tightly fitted over said sleeve.
References Cited in the file of this'patent UNITED STATES PATENTS