US2565624A - Holder for articles of magnetic material - Google Patents

Description

Aug. 28, 1951 R. E. PHELoN HOLDER VFOR ARTICLES OF MAGNETIC MATERIAL Filed April 22, 1949 /VVE/VTOR RUSSELL-QHELON By ATTORNEY Patented Aug. 28, 1951 UNITED STATES PATENT OFFICE HOLDER FOR ARTICLES OF MAGNETIC MATERIAL Russell E. Phelon, Longmeadow, Mass. Application April 22, 1949, Serial No. 88,968

The invention relates to a rack or holder utilizing one or more permanent magnets and adapted for holding articles consisting in whole or in part of magnetic material. A holder embodying the invention is particularly adapted for domestic use, as for instance in a kitchen, for holding cutlery, shears and the like. A holder embodying the invention is also adapted for use in a work shop or elsewhere for holding various small machinists or carpenters tools or other small articles.

A holder embodying the present invention is in many respects similar to the several forms of holders disclosed in my copendirig application for Holders for Articles of Magnetic Material, Ser. No. 9,134, led February 18, 1948. More specifically a holder embodying the present invention is somewhat similar to that shown in Figs. 8 to 10 of the said copending application.

One of the objects of the present invention is to provide a holder of the type specied wherein the pole pieces are substantially enclosed and concealed except at the article engaging faces thereof.

A further object of the invention is to provide a holder of the type specified wherein the pole pieces or the magnet or both are insertable in a body member from the rear thereof and engage the said body member to prevent relative forward movement and wherein a separate rear member is provided for engaging the pole pieces or the magnet or both to prevent relative rearward movement.

Another object of the invention .is to provide a holder of the type specied wherein the body member has vertically spaced upper and lower portions and has vertically extending portions or ribs adjacent the front of the said upper and lower portions and wherein the pole pieces or the magnet or both engage the said ribs to prevent relative horizontal movement.

Still another object of the invention is to provide a holder of the type specified wherein the body member is provided at the front with two vertically spaced series of longitudinally aligned slots and wherein the pole `pieces fit and extend through the slots of the respective series.

A further object of the invention is to provide a holder of the type specified wherein the pole pieces are notched to reduce the 'cross sectional area at least at one narrow zone and to thereby restrict the longitudinal flow of ilux across the said zone. `The purpose of the reduced cross sectional area is hereinafter fully explained.

Other objects of the invention are to provide Claims. (Cl. 175-7-367) various advantageous details of construction whereby the before-stated more general objects are attained.

Still other objects of the invention will be apparent from the drawing and from the following speciication and claims.

In the drawing I have shown in detail a preferred embodiment of the invention, but it will be understood that various changes may be made from the construction shown, and that the drawing is not to be construed as defining or limiting the scope of the invention, the claims forming a part of this specification being relied upon for that purpose.

Of the drawing:

Fig. 1 is a plan view of a holder 'embodying the invention.

Fig. 2 isa front view.

Fig. 3 is a vertical sectional the line 3 3 of Fig. 1.

Fig. 4 is a vertical sectional view taken along the line v4--4 of Fig. 1.

Fig. 5 is a horizontal view 5--5 of Fig. 2.

Fig. 6 is a horizontal sectional View taken along the line 6 6 of Fig. 2.

Referring to the drawing l0 represents a body or body member formed of non-magnetic material which may advantageously be molded plastic. Carried by the body member I 0 are two similar horizontal vertically spaced poleplates or pole pieces l2 and I4 formed of magnetic material. The pole pieces I2 and i4 are relatively thin and they are positioned with their vertically narrow front faces in vertical register with each other. At least one permanent magnet lis provided having opposite parallel pole faces at the top and bottom thereof, these pole faces engaging respectively with the pole pieces l2 and` I4. A single magnet may sometimes be suilicient but preferably and as shown at least two longitudinally separated magnets It and I8 are provi-ded.

The body member I0 is formed with top and bottom walls or portions 20 and 2`2 and preferably with a front wall 24, all integral with each other. A cavity Vinitially open at the rear is provided between the said top and bottom walls or portions 20 and 22, and when a front wall 24 is provided the cavity lis at the rear of the said front wall. The upper pole piece l2 is below and closely adjacent the top wall 20 and the lower pole piece His above and closely adjacent the bottom wall 22., When a front wall 2l is provided it is formed with vertically View taken along taken along 'the line spaced, or laterally spaced-apart, horizontal slits or slots through which the forward portions of the pole pieces project. Preferably there are two vertically spaced series of horizontally aligned slots, with a lportion of the front wall between each two adjacent slots. The pole pieces project beyond the top, bottom and front walls of the body member sufficiently to enable their front edge faces tovbe engaged with knives, tools or other articles to be held. The pole pieces engage the body member in such a manner as to positively prevent forward movement thereof beyond their normal projecting positions.

The body member is also preferably formed with transverse vertical end walls 26 and 28 formed integrally with the said top, bottom and front walls. When walls such as 26 and 28 are provided, the pole pieces I2 and I4 are between the said walls which cooperate with other parts to be described to prevent endwise or longitudinal. movement of the pole pieces. Preferably the transverse walls 26 and 28 are spaced inwardly from the extreme ends of the body member and they cooperate with short rear walls 30 and 32 .to form forwardly open notches adjacent the ends of the body member. The rear walls 3!) and 32 .have holes 34, 34 for the reception of devices such as screws for the attachment of the holder to a supporting wall.

The polepieces I2 and I4 are preferably provided with relatively deep notches extending rearwardly from their front faces, these notches dividing the front regions of the poles pieces into a plurality of longitudinally spaced forwardly projecting portions. As shown the notches in the two vpole, piecesr are in vertical register with each other, but as to this there may be variation. When the pole piecesl are notched, the front wall 24 of thebody'member has separate longitudinal slots'for receiving the several forwardly projecting" portionsof the pole pieces. When the notches are in vertical register the pole ,pieces have pairs of vertically registering forwardly projecting portions and the front wall 24 has pairs of vertically registering slots. The j number of pairs of projecting portions and slots may be varied, ybut as shown there are six pairs of `projecting portions and six pairs of slots.

When the pole pieces I2 and I4 are notched as described, the body member has integrally formed means which fit `the notches in the pole pieces.` With the notches in vertical register as shown, the body member is formed with an integral vertical rib 36 between each two adv jacent pairs of slots, each rib projecting rearwardly from the front wall and joining at its top and bottom with the top and bottom walls v28 and 22. When there are six pairs of slots as shown, there are five ribs 36, 36. The notches in the pole pieces I2 and I4 are positioned and shaped to receive and t the ribs 36, 36 and it will. be seen lthat these ribs cooperate with the walls 26 and 28 to prevent longitudinal movement of the pole pieces. These ribs serve as means for positively preventing relative forward movement of the pole pieces. A member structurally separate from the body member and formed of non-magnetic material is preferably provided for engaging the pole pieces to prevent relative rearward movement thereof. When the body member comprises top, bottom and end walls as shown, the said retaining member may be a plate 38 which entirely closes the rear of the aforesaid cavity in the body member. Ihe edges of the plate 38 are 4entered in recesses 4 formed in the top, bottom and end walls, the rear face of the plate being fiush with the rear of the body member. The plate 38 is held in place by cementing or otherwise. The pole pieces I2 and I4 are inserted forwardly through the open rear of the cavity and it will be seen that the front face of the plate 38, when in place, engages the rear edges of the pole pieces and serves to prevent relative rearward movement of thev said pole pieces. The rear plate 28 constitutes holding-means holding the said `pole- `plates or pole pieces and the said magnets in The magnets I6 and I8 are inserted forwardly through the open rear of the cavity, and preferably each of the magnets engages the body member so that relative forward movement is prevented and engages the rear plate 38, when in place, Aso that relative rearward movement is prevented. As shown each magnet engages oneor more of the ribs 36, 36 for preventing relative forward movement. Each magnet may advantageously be specially shaped for more effective engagement with the ribs l36, 36 and withothe rear plate 38. The magnet has two vertical ribs 48, 46 at the front which are spaced to engage two of the ribs 36, 36 at opposite sides thereof, and the ribs 36, 36 thus serve not only to lprevent relative forward movement of the. magnet butralso to prevent relative longitudinal movement thereof. The magnet is also formed at the rear with two vertical ribs 42, 42 which engage with the rear plate 38.

`It will be observed that the spaces between the ribs 36, 36 constitute a plurality of longitudinally separated retaining-recesses in the inner face of the wall 24 which recesses are located transversely intermediate the said slits or slots in the said wall 24. The longitudinally separated magnets are respectively positioned in part in the said retaining-recesses. The walls of the recesses or the said ribs constitute a plurality of longitudinally separated means on the front wall of the body member engaging respectively with the longitudinally separated magnets to prevent longitudinal movement thereof.

'Preferably' the front faces of the pole ypieces I2 and I4 instead of being straight are convexly curved. When the said pole piece faces are curved, the front edges of the top and bottom walls 28 and 22 of the body member and the front wall 24 thereof are also similarly curved.

In use the holder is suitably mounted on a supporting wall by means of devices such as screws inserted through the holes 34, 34. Articles formed in whole or in part of magnetic material can be placed in contact Vwith the verti-v cally registering front faces of the pole pieces andthey will be held magnetically.. Fig. 2 shows two knives and a screw driver so held. It will be understood. that while the knives and other articles are held sufficiently firmly so that they will not be separated by gravity or vibration, they can`V be readily removed when desired by grasping them and pulling them off.

The front faces of the pole pieces are narrow, and this .reduces any tendency for so much magnetism-to be shunted through a few articles at one end of the holder that there is not enough left to support articles at the other end. This results from the fact that the available amount of magnetism for each linear unit of length is limited by the saturation kof the iron inthe areasA of contact with the articles. The narrow faces s of the pole pieces provide a, high flux density between the articles and the said engaging faces, thus providing effective holding power inasmuch as the holding power is proportionate to the square of the flux density. It will be observed that each article is held at two relatively widely spaced positions, thus assuring a favorable leverage eifect on the article.

An additional important function of the notches in the pole pieces is to provide one or more zones of reduced cross sectional area, thus restricting the amount of magnetism that can Ibe carried longitudinally of the pole pieces and across the said zone or zones. Each notch is of such depth that the resultant zone of reduced cross sectional area is insufficient to carry a major portion of the flux from one forward projecting portion of a pole piece to another forward projecting portion thereof. Preferably and as shown, the notches are of such depths that the several reduced zones formed thereby have the same cross sectional area notwithstanding the convex curvature of the front faces of the pole pieces. The notches additionally reduce any tendency for a broad or heavy article engaged with the pole pieces at one position to carry so much of the total available flux that a smaller article engaged with the pole pieces at another position would not be properly held.

Inasmuch as the pole pieces have curved front faces, the total length available for engagement with articles to be held is substantially increased for a holder of the same overall length. The curvature of the pole piece faces still further reduces any tendency for a broad at article or tool when engaged with the said faces to carry such a large portion of the total available magnetic flux that smaller articles also engaged with the said faces might not be held with sufficient force to be retained in place. With the pole piece .f1

faces curved as shown, it is impossible for the said faces to be engaged throughout any substantial portion of their length by a broad flat article or tool. The broad article engages the said faces only at short zones and the total amount of iiux l is thus limited.

When the notches in the pole pieces are in vertical register, they facilitate the holding of an article such as a screw driver having a cylindrical shank. Without the notches such an article would be free to roll along the faces of the pole pieces and there would be nothing to hold it in a fixed position. However, when the shank is placed in a pair of notches as shown in Figs. 1 and 2, the tool is deiinitely located and is prevented from rolling along the face of the pole piece.

By reason of the extreme simplicity of construction, the cost of manufacture and assembly is reduced to a minimum. The body member is formed by a simple molding operation, the pole pieces are stamped, and the magnets are cast to the shape shown. The rear plate 38 is readily cut to the proper size. TheV several parts are manually assembled without any special tools or fixtures, and after assembly the .parts are held in assembled relationship by merely cementing the plate 38 in place. Furthermore, the enclosing or concealing of the major portions of the pole pieces results in additional economy, inasmuch as it is necessary to finish or polish the said pole pieces only at their exposed narrow front article engaging faces.

The construction embodying the invention provides an attractive appearance as the major exterior surfaces are all on they plastic body mem- 6 ber and this member can be made from material having any desired color.

What I claim is:

1. In a holder for articles of magnetic material. the combination of a longitudinally extending body member of nonmagnetic material having upper and lower portions provided respectively with vertically spaced downward facing and upward facing horizontal surfaces and having end walls connecting the said upper and lower portions, the said body member also having vertically extending continuous ribs adjacent the front and longitudinally spaced from the said end walls and from each other which ribs are connected lwith the said upper and lower portions and extend between the planes of the said downward and up-` ward facing horizontal surfaces, two vertically spaced fiat horizontal pole pieces of magnetic ma terial respectively engaging the said downward facing and upward facing surfaces of the body member and also engaging the said longitudinally spaced ribs of the body member so as to be thereby held against relative forward movement, the said pole pieces being exposed at the front be tween the said longitudinally spaced ribs and having vertically registering front faces which are spaced forward from the immediately ad jacent front faces of the said upper and lower body member portions, and a permanent magnet within the body member and between the pole pieces having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces.

2. In a holder for articles of magnetic material, the combination of a body member of non-magnetic material provided with horizontal top and bottom walls and also provided with at least one vertical rib near the front connecting the said top and bottom walls, a structurally separate rear plate of non-magnetic material connected with the top and bottom walls at the rear thereof, two flat horizontal pole pieces of magnetic material located respectively below and adjacent the top wall and above and adjacent the bottom wall, the said pole pieces having their front portions pro'- jecting forwardly beyond the said top and bottom walls with their front faces exposed at opposite sides of the rib and located in vertical register with each other and the said pole pieces engaging the said vertical rib to prevent relative forward movement and engaging the said rear plate to prevent relative rearward movement, and a magnet between the pole pieces having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces, the said magnet engaging the said vertical rib to prevent relative forward movement and engaging the said rear plate to prevent relative rearward movement.

A3. In a holder for articles of magnetic material, the combination of a body member of non-magnetic material provided with horizontal top and bottom walls and also provided with at least one vertical rib near the front connecting the said top and bottom walls, a structurally separate rear plate of non-magnetic material connected with the top and bottom walls at the rear thereof,V two flat horizontal pole pieces of magnetic material located respectively below and adjacent the top wall and above and adjacent the bottom wall, the said pole pieces having their front portions projecting forwardly beyond the said top and bottom walls with their front faces exposed at oppositeV sides of the rib and located in vertical register with each other and the said pole pieces engaging f the said vertical rib to prevent relative forward movement and engaging the said rear plate to prevent relative rearward movement, and a magnet between the pole pieces having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces, the said magnet engaging the rear edge of the said Vertical body rib to prevent relative forward movement and engaging the said rear plate to prevent relative rearward movement and the said magnet being formed at the front with a longitudinally facing shoulder engaging one side of the said vertical body rib to prevent relative longitudinal movement in one direction.

.' 4. In a holder for articles of magnetic material, the combination of a body member of nonmagnetic material provided with horizontal top and bottom walls and also provided with two longitudinally spaced vertical ribs near the front connecting the said top and bottom walls, a structurally separate rear plate of non-magnetic material connected with the top and bottom walls at the rear thereof, two flat horizontal pole pieces of magnetic material located respectively below and adjacent the top wall and above and adjacent the bottom wall which pole pieces have their front portions projecting forwardly beyond the said top and bottom walls with their front faces exposed at opposite sides of the ribs and located in vertical register with each other, the said pole pieces being notched to receive and lit the said vertical body ribs so as to prevent relative forward movement and the said pole pieces engaging the said rear plate to prevent relative rearward movement, and a magnet between the pole pieces having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces, the said magnet engaging the said rear plate to prevent relative rearward movement and engaging the rear edges of the said vertical body ribs to prevent relative forward movement and the said magnet being formed at the front with two opposite longitudinally facing shoulders engaging respectively with opposite sides of the respective vertical body ribs to prevent relative longitudinal movement in either direction.

5. In a holder for articles of magnetic material, the combination of a body member of nonmagnetic material provided with horizontal top and bottom walls and also provided with two longitudinally spaced vertical ribs near the front connecting the said top and bottom walls, aV structurally separate rear plate of non-magnetic material connected with the top and bottom walls at the rear thereof, two flat horizontal pole pieces of magnetic material located respectively below and adjacent the top wall and above and adjacent the bottom wall which pole pieces have their front portions projecting forwardly beyond the said top and bottom walls with their front faces exposed at opposite sides of the ribs andV located in vertical register with cach other, the said pole pieces being notched to receive and fit the said vertical body ribs so as to prevent relative forward movement and the said pole pieces engaging the said rear plate to prevent relative rearward movement, and a magnet between the pole pieces having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces which magnet has two vertical ribs at the rear engaging the said rear plate to prevent relative rearward movement, the said magnet at the front engaging the rear edges of the said vertical body ribs to` prevent relative' forward movement and the said magnet being formed at "the front Ywith two vertical ribs at opposite sides of the said body ribs and engaging them to prevent relative longitudinal movement in either direction.

6. In a holder for articles of magnetic material, the combination of a body member of nonmagnetic material provided with horizontal top and bottom walls, two at horizontal pole pieces of magnetic material located respectively below and adjacent the top wall and above and adjacent the bottom wall which pole pieces have their front portions projecting forwardly beyond the said top and bottom walls with their front faces in vertical register with each other, the said pole pieces having relatively deep longitudinally spaced notches therein which extend rearwardly from their front faces and which provide longitudinally spaced forward projections with zones of reduced cross sectional areas located between such projections and serving to restrict the amount of magnetic flux passing from one projection to the next adjacent projection, nonmagnetic means connected with the top and bottom walls of the body member and entering the notches in the pole pieces to prevent forward movement of the said pole pieces, and a permanent magnet between the pole pieces having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces.

7. In a holder for articles of magnetic material, the combination of a longitudinally extending hollow body member of nonmagnetic material initially open at the rear and having an inn tegral front wall, the said front wall having two vertically spaced horizontal slots therein, two vertically spaced fiat horizontal pole pieces extending through and fitting the respective slots in the front wall of the body member and having substantially vertically registering front faces which are spaced forwardly from the immediately adjacent front face of the said front wall, the said pole pieces engaging the body member to be thereby positively held against forward movement, a permanent magnet within the body member and between the pole pieces having opposite parallel horizontal pole faces at the top and bottom engaging respectively with the said pole pieces, and a nonmagnetic plate separate from the hollow body member and secured thereto at the initially open rear thereof which plate directly engages the pole pieces and the magnet to prevent rearward movement thereof with respect to the said body member.

8. In a holder for articles of magnetic material, the combination of a longitudinally extending hollow body member of nonmagnetic material initially open at the rear and having an integral front wall, the said front wall having therein two vertically spaced series of longitudinally aligned and longitudinally spaced horizontal slots, a portion of the body member being interposed between the longitudinally spaced edges of each two adjacent slots, two vertically spaced flat horizontal pole pieces extending through and fitting the slots of the respective series and having substantially vertically registering front faces which are spaced forwardly from the said front wall, the said pole pieces being notched to receive the por` tions of the body member between each two adjacent slots and the said pole pieces engaging the body member to be thereby positively held against forward movement, a permanent magnet within the body member and between the pole pieces having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces, and means for holding the pole pieces and the magnet to prevent rearward movement thereof with respect to the body member.

9. In a holder for articles of magnetic material, the combination of a longitudinally extending body member of non-magnetic material having two vertically spaced series of longitudinally aligned horizontal slots therein extending through the front face thereof, the slots of each series being longitudinally spaced and having a portion of the body member positioned between each two adjacent slots, two vertically `spaced flat horizontal pole lpieces extending through and fitting the slots of the respective series and having substantially vertically registering front faces which are spaced forward from the immediately adjacent front face of the body member, the said pole pieces engaging the said portions of the body member between the slots to be thereby held against forward movement, and a permanent magnet within the body member and between the pole pieces having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces.

10. In a holder for articles of magnetic material, the combination of a body member of nonmagnetic material provided with top and bottom walls and also provided with an integral vertical front wall connecting the top and bottom walls and having two vertically spaced series of longitudinally aligned horizontal slots therein, the slots of the upper series being adjacent the top wall and below it and the slots of the lower series being adjacent the bottom wall and above it, two flat horizontal pole pieces of magnetic material located between the top and bottom walls of the body member and having their front portions projecting forwardly through the said slots of the respective series in the front wall of the body member, the said pole pieces having their front faces in vertical register with each other, means formed integrally with the front wall of the body member and engaging the pole pieces to positively prevent relative forward movement thereof, a structurally separate member of non-magnetic material adjacent the rear of the body member and engaging the pole pieces to prevent relative rearward movement thereof, and a magnet behind the said front wall of the body member and having opposite parallel `pole faces at the top and bottom engaging respectively with the said pole pieces.

11. In a holder for articles of magnetic material, the combination of a body member of nonmagnetic material provided with top and bottom walls and also provided with an integral vertical front wall connecting the top and bottom walls, the said front wall having therein a plurality of pairs of vertically spaced and vertically registering horizontal slots, the upper slot of each pair being adjacent the top wall and below it and the lower slot of each pair being adjacent the bottom wall and above it, two flat horizontal pole pieces of magnetic material located between the top and bottom walls of the body member and having a plurality of pairs of portions extending forwardly through the slots of the respective pairs the front wall of the body member, the said pole pieces engaging the body member to positively prevent relative forward movement and the front faces of the projecting pole piece portions of each pair being in vertical register with each other, a structurally separate member of nonmagnetic material adjacent the rear of the body member and engaging the pole pieces to prevent 10 relative rearward movement thereof, and a magnet behind the said front wall of the body member and having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces.

12. In a holder for articles of magnetic material, the combination of a body member of non-magnetic material provided with top and bottom walls and also provided with integral vertical end walls and an integral vertical front wall connecting the top and bottom walls, the said front wall having a plurality of pairs of vertically spaced and vertically registering horizontal slots therein with the upper slots adjacent the top wall and below it and with the lower slots adjacent the bottom wall and above it, a structurally separate rear plate of non-magnetic material connected with the top and bottom walls of the body member and also with the end walls thereof and serving to entirely closeV the body member at the rear thereof, two horizontal pole pieces of magnetic material located between the top and bottom walls of the body member and between the end walls thereof and having their front portions projecting forwardly through the respective upper and lower slots in the front wall of the body member, the said pole'pieces having their front faces in vertical register with each other and the said pole pieces engaging the body member to positively prevent relative forward movement and engaging the body member end walls to prevent relative longitudinal movement and engaging the rear plate to prevent relative rearward movement, and a magnet located behind the said front wall of the body member and in front of the rear plate and having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces.

13. In a holder for articles of magnetic material, the combination of a longitudinally extending body member of non-magnetic material 'having two vertically spaced sets of longitudinally aligned and longitudinally spaced horizontal slots therein extending through the front face thereof, a portion of the body member being interposed between the longitudinally spaced edges of each two adjacent slots, two vertically spaced flat horizontal pole pieces extending through and fitting the slots of the respective sets and having vertically registering front faces which are spaced forwardly from the immediately adjacent front face of the body member, the said pole pieces engaging the front portion of the body member to be thereby positively held against forward movement, a plurality of longitudinally spaced permanent magnets within the body member and between the pole pieces having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces, means engaging the pole pieces and the magnets to prevent rearward movement thereof, and means on the front portion of the body member engaging the magnets to prevent longitudinal movement thereof.

14. A magnetic holder of the character referred to, including in combination: a hollow body of nonmagnetic material having a pair of laterally spaced-apart slits extending through a wall thereof from the interior to the exterior thereof, the said wall having a plurality of retaining-recesses in its inner face which recesses are located transversely intermediate the said slits; a pair of complemental pole-plates respectively mounted in the slits in the said wall of the body; a plurality of permanent magnets respecl1 tively positioned in the retaining-recesses in the said body and extending between the two said pole-plates; and holding-means holding the said pole-plates and magnets in place.

15. In a holder for articles of magnetic material, the combination of a body member of nonmagnetic material provided with horizontal top and bottom walls and with a vertical front wall connecting the top and bottom walls and also provided with two longitudinally spaced ribs projecting rearward from the front wall, the said front .wall having therein between the said ribs a pair of vertically spaced and vertically registering horizontal slots with the upper slot adjacent the top wall and below it and with the lower slot adjacent the bottom wall and above it, a structurally separate rear plate of non-magnetic material connected with the top and bottom walls of the body member, two horizontal pole pieces of magnetic material located between the top and bottom walls of the body member and having their front portions projecting forwardly through the said slots in the front wall of the body member, the said pole pieces having their front faces in vertical register with each other and the said pole pieces engaging the said ribs to prevent relative forward movement and. engaging the rear plate to prevent relative rearward movement, and a magnet having opposite parallel pole faces at the top and bottom engaging respectively with the said pole pieces, the said RUSSELL E. PI-IELON.

REFERENCES CITED The following references are of record in the file of this patent:

VUNITED STATES PATENTS Number Name Date 361,248 Winton Apr. 12, 1887 675,323 Clark May 28, 1901 1,081,462 Patton Dec. 16, 1913 1,554,236 Simmons Sept. 22, 1925 1,624,741 Leppke Apr. 12, -1927 2,186,074 Koller Jan. 9, 1940 2,327,748 Smith Aug. 24, 1943 2,337,248 Koller Dec 21, 1943 2,337,249 Koller Dec. 21, 1943 2,414,653 Lookholder Jan. 21, 1947 FOREIGN PATENTS Number Country Date 238,118 Germany Apr. 24, 1909 444,786 Great Britain Mar. 27, 1936 544,110 Great Britain Mar. 27, 1942

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