US2677294A - Magnetic driving implement - Google Patents

Description

May 4, 1954 F. G. CLARK 2,677,294

MAGNETIC' DRIVING IMPLEMENT Filed Nov. 25 1950 70 7 fr 1"* 325 f) atented May 4, 1954 NITED STATE TENT OFFCE MAGNETIC DRIVING IMPLEMENT Frederick G. Clark, Buffalo, N. Y., assignor of one-half to Wade Stevenson, Buffalo, N. Y.

4 Claims.

This invention relates to improvements in driving implements for rotating and driving fastenings such as nuts, bolts, screws, or the like, and which are provided with high energy permanent magnets for holding the fastenings in operative position on the implement while the fastenings are being positioned for driving.

High energy magnets of the type used on implements of this nature are made of cast or sintered alloys which when magnetized are capable of exerting a much stronger magnetic force than magnets made of steel or iron. Such alloys, however, are very brittle and readily broken and must, therefore, be supported on the implements in such manner that they are protected against shocks, impacts, and the like, and they should not be required to transmit any forces, such as torque or pressure from the implement to the fastening.

One of the objects of this invention is to provide an implement of this type in which the magnet is protected against damage and which includes means of improved construction for transmitting the forces from the shank of the implenient to the driving element or socket thereof without depending on the magnet to transmit any of these forces. A further object is to provide an implement of this type with a socket which is so mounted on the shank of the implement that it may be readily removed from the implement and replaced by another socket, and in which this mounting of the socket in no way interferes With the yieldable mounting of the magnet. Still another object of this invention is to provide a high powered alloy magnet of this type with a tip made of a durable magnetic material so that the fastenings to be driven will at no time come into contact with the magnet and chip or otherwise damage the same.

Other objects and advantages will be apparent from the following description of one embodiment of the invention and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawings:

Fig. 1 is an elevation, partly in section, of a magnetic implement for driving fastenings.

Fig. 2 is a fragmentary central sectional elevation thereof, on an enlarged scale, showing the implement with the socket removed therefrom.

Fig. 3 is an end view of the construction shown in Fig. 2.

Fig. 4 is an end view of the implement shown in Fig. 1.

Fig. 5 is a fragmentary elevation, partly in sec- 2 tion, of a driving implement of modified construction.

Fig. 6 is a fragmentary elevation thereof, taken at approximately degrees from that shown in Fig. 5.

The driving implement includes a shank l of any usual or suitable construction, that shown being or" a type commonly used in connection with power driven screw drivers. This shank has the inner end portion 8 thereof of hexagonal or other non-circular cross section for forming a driving connection with a rotatable part of a power actuated screw driver or similar tool. It will be understood, however, that this shank may be of any other suitable or desired construction and may, for example, be a part of a hand driven implement for imparting rotation to a fastener. The shank shown also includes a substantially cylindrical portion [-3, which terminates at its outer end in an outwardly extending shoulder portion l, that shown being of annular form. Out- Wardiy beyond this shoulder portion, the shank has a projecting part or stud H of square or other nonircular cross section which serves to transf mit torque from the shank to a socket I2 of hollow or tubular form and the outer end of which is provided with a recessed portion I4 which is formed to receive the head of the fastening tobe driven. The opposite or inner end of the socket l2 is provided with a recess l5 of square or other non-circular cross section, which is so formed that the stud i l of the shank may fit snugly into this recess, thus forming a driving connection for transmitting torque from the shank and the socket to a fastening I6, such for example as the one shown in broken lines in Fig. l.

Suitable means are provided which cooperate with the outwardly extending shoulder l0 of the shank for removably holding the socket l2 on the shank 'l of the implement, and in the particular construction shown for this purpose in Figs. 1 to 4, a lock or clamping nut i8 is provided which has a shoulder I9 adapted to engage one side of the projection ID of the shank. The lock nut is also provided with a threaded portion formed to engage a threaded part 20 of the socket. Consequently, by tightening the lock nut, the socket will be clamped rmly on the shank so that the inner end of the socket engages the outer face of the annular projection IIJ. 2| represents a snap or spring ring which may be resiliently held on the shank 'l to retain the lock nut I8 on the shank, so that the same will not become lost while changing sockets. The threads on the socket and lock nut are preferably left-handed so that if the lock nut comes in contact with some object while rotating in a righ hand direction, it will not be unscrewed from the socket.

22 represents a high energy permanent magnet which is preferably of the bar type which is magnetized lengthwise thereof so that the ends of the magnet constitute opposite poles thereof. This magnet is arranged partly within a nonrnagnetic holder 24 Aand partly within a bore or aperture 25 formed in the outer end of the shank l. This bore or aperture in the shank is provided at the outer end thereof with a portion 26 of enlarged internal diameter. The Vmagnet holder, in the construction shown, is in the form of a sleeve and the inner end -o :the sleeve may have a driving t within the -hole or aperture 28 formed in the shank l'. The magnet :is arranged within its holder and within the aperture 25 of the shank in such a manner that the magnet may freely slide lengthwise of the sleeve and the aperture f2.5. The vmagnet `is urged outwardly with reference to the shank by any suitable yielding'ineans, such for example, as a spring 2l', and the outer end .of `the holder or sleeve is preferably provided with an inwardly extending flange 23 which `forms a stop to limit the extent to which the magnet may be urged outwardly by the vspring 2l.

In the socket 'l2 the recessed end portions i@ and l are connected by a bore 3Q which oi suilicient diameter -so that the magnet holder may extend into this portion of the socket. The-bore 30 is of smaller diameter than the recess lil at the outer end of the socket, thus forming an outwardly facing shoulder at the junction-oi' the bore Si) and the recess `Ill against which the fastenings will -seat when 'be-ing driven into the work. vrl'lhe magnet holder 24 is so proportioned ,positioned that the outer end of tl e in may extend vbei/ond the holder into the recessed po; Yion `lfl of the :socket suiiioiently rto hold any type of fastening on which lthe socket ma?,7 `be used, including, for example a fastening with a recessed or concave head, as shown .in broken lines in Fig. l. It 'will be obvious, however, that when .endwise pressure is applied -by means 'of the driving implement aga-inst the fastening, the magnet will be pushed inwardly against the action of thespring until the fastening seats on the shoulder lfortified at the -inner end of the recessed portion ifi. Consequently, no pressure other than the spring 2l will be exerted against the magnet during the driving of a fastening. yielding-ly mounting the magnet in this manner, the socket may cooperate with fastenings having heads of various .contours across the tops -of the heads.

it will be obvious from the tion that the shank l, the socket i2 and the lock nut lil may be formed `o any suitable or desired magnetic material, and consequently, the socket may be made of a high grade hard steel which will have the maximum resistance to wear by the fastenings. When such magnetic materials are user., the outer ends of the socket member l2 and the outer end of the magnet will be of opposite polarity and thus .securely .and correctly hold the .fastenings in substantial Vaxial alinement with the socket. If vfor .any .reason it should be desired .not .to have the outer end of the .socket member magnetized, .this can be accomplished in .any-desired manner by .breaking the magnetic circuit leading from the inner end of the magnet to :the socket member, .for example, by making -theshank .l of non-,magnetic foregoing construcor substantially non-magnetic material. The socket may at any time be readily removed from the implement by turning the lock nut in a direction to release the socket whereupon another socket may be applied to the implement, either to replace one that has been worn out or to enable the implement to cooperate with iastenings of different shapes or sizes.

Because of the fact that the high .power magnets used in connection rwith'implements of this type are fragile and easily chipped or otherwise damaged by the fastenings with which the tool cooperates, I `have provided the magnet with a hard tip at the outer end thereof made of suitable magnetic material, the tip being so positioned that it will engage with the fastenings held Aby ythe magnet. These hard tips may be of any suitable construction and material. Preferably -the tips are made of steel, suitably hardened for maximum wear. In the construction shown, I have provided tips which have end portions 32 formed to extend beyond the outer end of the magnet holder or sleeve 25, and a portion 33 Aof arger diameter which is located r within the magnet holder and abuts against the outer flange 2S of this holder to limit the extent to which magnetic tip may extend outwardly beyond the magnet holder. This tip may be secured to the magnet 22 in any suitable manner, or desire-Ll, the magnetic force of the magnet may be depended upon to hold the hardened tip on the magnet. Furthermore, the spring `2 at all times urges the magnet into engagement with the tip. The tip thus in effect yconstitutes a part of th, agnet. The reduced end 32 of the tip extends into the recess ill of the socket suf."- ciently to engage with any type of fastening which may enter into the recessed end i4 of socket member. The tip thus takes all of the wear, blows or impacts received from the fastenings, thus avoiding damage to the magnet by chipping or otherwise.

When the fastening has .been placed into proper relation to the work. for driving the same and when pressure is applied lengthwise of the shank 'i against the fastening, the magnet will `be pushed inwardly 4against the action of the spring so that the magnet `will not be subjected to any pressure which may be applied to the fastening, other than the pressure of the spring 2l, which is relatively `light and not suiiicient to damage the magnet.

in Figs. v5 and. 6, I have .shown .a modied construction for removably holding the socket on the shank. In this construction, the shank may be similar to that shown in Figs. l to 4. A slightly diierent socket .member .35 is employed, the inner end of which also bears against the outer shoulder .formed Von the projection Vill of the shank. The bore of :the socket member 1also is formed to cooperate with a non-,circular portion ,il of the shank, Aas ydescribed in Figs. 1 to 4. In order to hold this ,socket meinberon the shank, provide a spring locking'clip having an annular portion 3B extending aboutthe ,cylindrical shank portion 9 Vand .having loutwardly extending arms 3l which Aextend vover the outwardly projecting portion i9 and are provided at theirouter ends with .detent members 38 :formed -toengage in a. groove .or recess .39 .formed on the outer surface of the socket member. By means of thisconstruction, .the `socket member is .releasably held on the shank and may be readily removed therefrom .by exing the `arms `3J outwardly so that the detent portion 38 thereof will move out of the groove 39.

By means of the construction described, it will be noted that the sockets may be secured to the shank by means which are located entirely on the outer surface of the shank, such for example as the outwardly extending shoulder I and a lock or clamping nut or a clip. This construction has the advantage that the interior of the shank may be bored out to any desired depth to receive the magnet and the spring 21 so that the magnet may be of the desired length and the spring also may be made long enough to amply cushion the magnet against shocks. This bore of increased length also makes it possible to add a steel tip to the outer end of the magnet. The construction has the further advantage that the socket is very securely held on the shank and a saving in the cost of sockets may be effected because of the reduced length of the same. The constructions described also facilitate the ready removal and replacement of a socket on the shank.

The term non-magnetic is herein used in the practical sense to designate materials of very low magnetic permeability.

It will be understood that various changes in theI details, materials, and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention, as expressed in the appended claims.

I claim as my invention:

1. A tool for driving screw threaded fastenings, said tool including a shank, a socket on the outer end of said shank for cooperating with the fastenings to be driven, a magnet extending into said socket for holding by magnetic force the fastenings to be driven, the outer end of said magnet having a tip of magnetic material oi greater wear and impact-resisting properties than said magnet, a fastening when in said socket being contacted by said magnetic tip, and said tip forming a part of a magnetic circuit including said magnet and a fastening.

2. A tool for driving screw-threaded fastenings, said tool including a shank, a socket on the outer end of said shank for cooperating with the fastenings to be driven, a magnet extending into said socket for holding by magnetic force the fastenings to be driven, the outer end of said magnet having a tip of magnetic material of greater wear and impact-resisting properties than said magnet, a fastening when in said socket being contacted by said magnetic tip, said tip forming a part of a magnetic circuit including said magnet and a fastening, stop means for limiting the extent to which said tip may move outwardly relatively to said socket, and spring means acting on said magnet in a direction to urge said magnet in contact with said tip and for urging said tip outwardly against said stop means.

3. A tool for driving screw threaded fastenings, said tool including a shank, a socket on the outer end of said shank for cooperating with the fastenings to be driven, said shank having an axially extending aperture, a magnet slidably arranged in said aperture, a magnet holder of non-magnetic material extending beyond said shank and into said socket and extending about the outer portion of said magnet, a tip of magnetic material of greater Wear and impact-resisting properties than said magnet at the outer end of said magnet, said holder having a stop engaging said tip to limit the outward movement thereof, and spring means acting on said magnet and yieldingly urging the same against said tip and urging said tip into its outer position relatively to said magnet holder.

4. A tool according to claim 3, in which the outer end of said socket is recessed to receive a fastening, and in which said tip extends into said recessed portion for contact with a fastening to be driven, said tip and magnet being movable inwardly against the action of said spring means when pressed against a fastening in an axial direction of said shank and socket.

lteerences Cited in the le of this patent UNITED STATES PATENTS Number Name Date 512,381 Keyes Jan. 9, 1894 1,328,428 Graham Jan. 20, 1920 1,419,100 Ayotte June 6, 1922 1,492,908 Trumbo May 6, 1924 1,542,266 Palmer et al June 16, 1925 1,643,901 Peterson Sept. 27, 1927 2,260,055 Reardon Oct. 2l, 1941 2,475,936 Allen July 12, 1949 2,502,025 Raup Mar. 28, 1950 2,624,223 Clark Jan. 6, 1953 2,630,036 Brown Mar. 3, 1953 FOREIGN PATENTS Number Country Date 474,971 Germany Apr. 16, 1929

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