Magnetic catch

Oct. 6, 1964 a. w. ahlgren 3,151,902

MAGNETIC CATCH

Filed March 13, 1962

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ITO

3,151,902

Patented Oct. 6, 1S64

United States Patent Office

3,151,902 MAGNETIC CATCH

Axel W. Ahlgren, Rockford, El., assignor to Amerock Corporation, Rockford, EL, a corporation of Illinois

Filed Mar. 13, 1962, Ser. No. 179,422

Claims. (Ci. 292—251.5)

This invention relates to magnetic catches for latching doors releasably in closed positions, and relates more particularly to catches of the type including a magnet assembly movably mounted in a molded plastic case with the pole faces of the assembly projecting outwardly through an open side of the case for engagement with a strike, the assembly being spring-urged out of the case and yieldable therein to cushion contact between the strike and the pole faces.

The primary object of the present invention is to provide in a catch of the above character a case constructed in a novel manner to prevent breakage of the case under the excessive forces occasioned by abusive slamming of the door.

A more specific object is to provide a bumper on the case engageable with the strike after a predetermined amount of yielding of the spring but before the assembly abuts against the end wall of the case whereby the force of abusive closing of the door is absorbed by the entire case rather than the end wall alone.

Another object is to form the bumper in a novel manner to accommodate pivoting of the assembly in the case to aline the pole faces with the strike.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawing, in which

FIGURE 1 is a fragmentary side elevational view of a catch embodying the novel features of the present invention cooperating with a strike to hold a door in a closed position relative to a frame, the door and the frame being shown in section.

FIG. 2 is an enlarged perspective view of the catch shown in FIG. 1.

FIG. 3 is an end elevational view of the catch.

FIG. 4 is a sectional view taken along the line 4—4 of FIG. 3.

FIG. 5 is an exploded perspective view of the magnet assembly.

As shown in the drawings for purposes of illustration, the invention is embodied in a magnetic catch 10 adapted to be mounted on one of a pair of door and frame members 11 and 12 respectively for coaction with a strike 13 mounted on the other of the members to hold the door releasably in a closed position. Herein, the catch is mounted adjacent the free edge 14 of the upper side of a shelf constituting the frame member 12 and the strike is mounted on the inner side of the door in alinement with the catch when the door is closed.

The catch 10 includes a case 15 composed of nonmagnetic material formed with a magnet-receiving recess 17 therein opening outwardly through one end 18 of the case. Preferably, the case is molded in one piece of a suitable plastic material and includes two spaced side walls 19 and 20, an end wall 21 opposite the open end 18, and two vertical walls 22 closing the remaining sides of the case. Projecting laterally from the side walls 22 are two wings 23 which lie against the top of the shelf and are formed with elongated parallel slots 24. The latter receive suitable fasteners such as screws 25 driven into the shelf to mount the catch thereon vzith the open end 18 closely adjacent the edge 14 and facing toward the door.

A magnet assembly 27 is disposed within the recess 17 and comprises a flat permanent magnet 28 with two flat plates 29 composed of magnetic material lying on opposite sides of the magnet. The end portions of the plates at one end of the assembly project through the open end ₅ of the case and terminate in spaced parallel end surfaces 30 disposed in a common plane and constituting the pole faces of the magnet assembly.

Means is provided to coact between the case and the assembly and retain the latter in the case while permitting limited endwise movement of the assembly toward and away from the end wall 21. Herein, this means includes ears 31 struck outwardly from the inner end portions of the pole plates to project into grooves 32 extending across the upper and lower walls 19 and 28 of the case. Each 15 groove is wider than the thickness of the associated ear so that the plates may shift back and forth in the case as permitted by the spacing of the opposite edges of the grooves. As shown in FIG. 4, the rear edges of the grooves are formed by the end wall 21 which abuts 20 against the inner ends of the pole plates to limit inward shifting of the assembly.

To retain the magnet 28 between the pole plates 29, the latter project beyond each end of the magnet and are formed with inwardly extending abutments engageable 25 with the opposite ends of the magnet to prevent the latter from shifting endwise in either direction from between the plates. As shown in FIGS. 4 and 5, these abutments are formed by lugs 33 and 34 struck inwardly from the upper and lower plates respectively adjacent the pole 30 faces, and a pair of lugs 35 struck inwardly adjacent the other end of each plate. The two lugs 35 on each plate are spaced apart laterally to engage the magnet on opposite sides of its centerline. Thus, the magnet is held between the plates and the entire assembly is movable in 35 the case as one unit. The width of the assembly preferably is less than the spacing of the walls 22 to permit sidewise pivoting of the assembly about a vertical axis to aline the plane of the pole faces 30 with the plane of the strike 13.

Herein, the bottom wall 20 of the case is made relatively thin and is bowed upwardly to bear resiliently against the lower pole plate and hold the assembly together and firmly against the top wall 19 with the ears 31 seated in the grooves 32. With this arrangement, the 45 catch may be assembled simply by sliding the magnet assembly into the case through the open end. The resilient bottom wall yields downwardly to permit the ears to pass and then snaps back to interlock the ears and the grooves.

When the door 11 is closed, the assembly and the case are subjected to a shock of a magnitude depending upon the closing force applied to the door. To cushion such shocks, a spring 37 is provided to act between the case and the assembly and urge the latter yieldably outwardly 55 relative to the case. Preferably, this spring is simply an arcuately curved flat spring disposed between the end wall 21 and the inner end of the assembly to bear at its ends against the end wall and intermediate its ends against the inner ends of the pole plates (see FIG. 4). Thus, the 6° spring normally holds the inner end of the assembly spaced from the end wall 21 with the pole faces projected outwardly and positioned to engage the strike, and is yieldable inwardly under the force with which the strike contacts the pole faces, such forces tending to flatten the 65 spring against the end wall.

In accordance with the present invention, the plastic case 15 is constructed in a novel manner to prevent breakage of the end wall 21 under excessive forces occasioned by abusive slamming of the door 11. For '° this purpose, the outer edge of one of the side walls is spaced from the end wall a distance greater than the

3,151,902 length of the magnet assembly 27 to form a bumper 38 engageable with the strike 13 after a predetermined amount of yielding of the spring and before the assembly abuts against the end wall. Accordingly, excessive closing forces are absorbed by the bumper and the entire box-like structure of the case rather than by the end wall alone.

In this instance, the bumper 38 is formed on the free edge of the upper wall 19 of the case and comprises a lip molded integrally with the case to project toward the strike from the open end of the case. The lower side of the bumper is flat and lies closely adjacent the upper pole plate while the upper side of the bumper preferably curves upwardly and rearwardly from the free edge as shown in FIGS. 1 and 4. Adjacent the center of the bumper, the latter is spaced inwardly from the pole faces a distance less than the normal spacing of the inner end of the magnet assembly from the end wall 21. (see FIG. 4). For example, when the assembly normally is %₄ inch from the end wall, the center of the bumper may be %₄ inch from the pole faces.

When the door is closed with a force sufficiently great to flatten the spring, the strike 13 contacts the free edge of the bumper and is stopped thereby before the magnet assembly is forced against the end wall. The force of closing, therefore, is applied against the bumper and the upper wall 19. It will be seen that this force is partially cushioned by the resilient yielding of the bumper, but is largely absorbed by lateral flexing of the case which yields away from the strike intermediate the mounting screws 23. As a result, the entire box-like structure absorbs the shock and this structure is capable of withstanding shock loads over four times greater than the loads which would break out the end wall.

As shown in FIG. 2, the bumper 38 preferably is relieved from the central portion toward each side of the catch to accommodate pivoting of the magnet assembly in the case. Thus, the bumper does not interfere with pivoting of the assembly in one direction or the other to aline itself with a misalined strike.

From the foregoing, it will be seen that a catch 19 constructed as described above is capable of withstanding substantially greater shock loads than prior catches of this general type. This advantage is gained simply, inexpensively, and without affecting the attractive appearance or effectiveness of the catch by forming the bumper 38 on the edge of the upper side 19 adjacent the open end of the case to abut against the strike before the latter forces the magnet assembly against the end wall of the case whereby the force of closing is absorbed by the lateral flexing of the entire box-like case rather than by the end wall alone.