US2946614A

US2946614A - Low friction strike plate

Info

Publication number: US2946614A
Authority: US
Inventors: Fred J Russell
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-12-09
Filing date: 1958-12-09
Publication date: 1960-07-26
Anticipated expiration: 1977-07-26

Description

y 1960 F. J. RUSSELL 2,946,614

LOW FRICTION swam: PLATE Filed Dec. 9, 1958 INVENTOR.

M w 52 6% %4, 45 45' By AI'Tdk/VE as,

LOW FRICTION STRIKE PLATE Fred J. Russell, 3800 Don Felipe Drive, Los Angele's, Calif.

Filed Dec. 9, 1958, Ser. No. 779,133

4 Claims. (Cl'. 292-34111) The invention relates to strike plates for: door locks adapted to be attached to a suit-able door frame which are of composite structure and incorporate a material having a low coefiicient of friction combined with a metal strike plate base structure. I

The most commonly used' material forstrike plates usedwith l-atch bolts, locks, and comparable structures is, metal. Although various dilferent metals and metal finishes are employed, one of the more. commonly used metals is brass which can readily be made with an attractive polished natural or lacquered finish or plated with an appropriate plating material. Strike plates ingeneral use comprise as a rule a single piece of metal sheetmaterial having one portion provided with a latch bolt aperture adapted to be fastened to a door frame and having another portion which constitutes astrike lip. The lip is regularly curved in some suitable fashion for the purpose of guiding the strike bolt over the strike platev into the aperture, thereby tosecure the door in closed position.

Although strike plates in general use have been satisfactory from a purely functional standpoint, namely, that of guiding the latch bolt into place and holding it in place, they lack certain desirable advantages such, for example, as a low friction engagement for latch bolts which, because of greater extending length, have a severely angled face contact with the strike lip.

It is therefore among the objects of the invention toprovide a new and improved composite strike plate wherein the advantages of metal are combined with the advantages of a non-metallic material having alow friction coefficient in such fashion that the composite strikeplate is durable, rugged, quiet, and of relatively inexpensive construction.

Another object of the invention is to provide a new and improved composite strike plate which combines the qualities of metal and a low coefficie'nt synthetic plastic material in such fashion that the combination is rugged and at the same time presents a dry, low friction surface over which a strike bolt may ride to latching position.

Still another object of the invention is to provide a new and improved composite strike plate wherein certain portions of the metal are replaced by a synthetic plastic material of desired characteristics with the combination so fashioned that the parts of different material interlock when assembled so as to present an easily installed rugged and dependable installation productive of a neat and compact appearance on the door frame.

With these and other objects in view, the invention consists in the construction, arrangement and combination of the various parts of the device, together with the method for achieving the same, whereby the objects c ontemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

In the drawings:

Figure l is a plan view of oneform of composite strike sible by the presence of the low friction element pets 2,946,614 Patented July 26,. 196.0

friction element.

Figure 2" is a cross-sectional view on the line- 2:-2 of Figure Figure 2a is an enlarged cross-sectional view of: the lip of'the strike.

Figure 3 is a side elevational view of an installation: partially broken away showing another form of com posite strike plate structure installed on a door frame.

Figure 4 isa rear elevational View of the composite structure of Figure 3.

Figure 5 is a cross-sectional view taken on the line 5-5 of Figure 3.

In an embodiment of the invention chosen for the purpose of illustration there is shown a composite strike comprising ametal plate element 10 which consists of: a fastening section 11 and a lip section 12. In the fasten-- ing section is a latch bolt opening 13 and conventional screw holes by means of. which: the composite. plate is attached to the door frame. When so mounted there is customarily provided a recessed area 17 in a surface 18, ofthe frame which is also provided with a hole 19 for reception of thelatch bolt when extended at the samerelative location as the latch bolt opening 13.

In the lip section 12 is anopening 20 locatedbetween an outer edge 21 and the fastening section 11. Positioned in anchored relationship in the opening 20- is a low friction element 22. The element 22 is preferably one which? neatly fills the opening 20 and is secured thereto was in effect to become an integral part of the lip. The securing of the lowfriction element 22 may be effected by pro'-- viding abeveled shoulder 23 on the exposed side to overhe the exposed surface of the lip section12. A straightsided portion 214 isdesigned to fit within the walls of the opening 20 and a bead 25 of somewhat limited size PfiQvided to' overlap the. under-face of the lip 12'.

The material comprising the low friction element 22 is' preferably an appropriate synthetic plastic material which may be a member of a group of plastics of nitrogenous structure known as polyamides of which nylon is an* example. These plastics are desirable in that they are extremely tough, long-wearing and more especially havea low coeflicient of friction on their surface. The syn-'- thetic plastics successful for use as herein described are customarily extremely tough bodied and capable of being fabricated into shapes of uniform or varied thickness.

Moreover, this material can be cast and when extracted from the mold before cooling is somewhat flexible. Forf that reason, shallow recesses can be formed Without the customary draw required of molded parts and hence the bead 25 can be initially c'as't when the element 22- is cast and readily withdrawn from the mold. After'the element has hardened, the bead also hardens and becomes a fas tening element when forced into the position shown in, Figure 2 which, once engaged, will firmly anchor the part" inplace.

in a composite structure of the type described, the" tion as shown in Figure 2, the lip will extend to a position wherein it will be struck by a beveled face- 26' of a latch bolt 27. This is the point of greatest impact and is the area wherein the latch bolt will engage the low;

friction element '22. The diminished friction made pus;

mits the latch bolt to slide readily over the lip until it reaches a portion adjacent the fastening section 11 of the metal plate element 10. At this point the bolt will be at substantially 90 degrem with respect to the composite element and will slide freely with its tip 28 in contact until it falls -within the latch bolt opening 13.

r 'Moreover, constructed as shown the lip has all of the strength expected of a metal lip reinforced by the binding in place of the low friction element 22.. More particularly, however, the element 22 by extending slightly above the surface of the metallic portion of the lip makes certain to engage the latch bolt and provide an area of diminishing friction.

A composite strike plate in this instance is composed of two plates, namely, a metal plate and a plastic plate identified more particularly as a metal plate element 29 and an element 30 comprising an appropriate synthetic plastic material of the same type as described in connection with Figures 1 and 2.

The metal element 29 in the embodiment chosen for illustration consists of a substantially rectangular fastening section 31 having screw holes 32 therein and provided with a rectangular bolt aperture 33. On an edge 34 of the fastening section 31 is a lip indicated general 1y by the reference character 35 and consisting of a flat portion 36 and a curved portion 37, the curved portion terminating in an outer edge 38. In the lip is an opening 39 which extends throughout a large breadth of both the flat portion and curved portion and is spaced from the bolt aperture 33.

The element 29 consists of a secondary fastening section 40 which may be rectangular in form and slightly smaller than the first identified fastening section 31. In the secondary fastening section are slots 41 substantially coinciding with the screw holes 32 so that the screws 42 when passed therethrough will secure both sections in proper position but permit of a certain amount of adjustment of the element 29 with respect to the element 30.

Also comprising part of the element 29 is a secondary lip 43 adjoining an edge 44 of the secondary fastening section 40. 'It will be noted, however, that the secondary lip 43 is thicker than the secondary fastening section 40 so that an outer surface 45 when in assembled position projects somewhat beyond the outer surface 46 of the metal element 29. The area and proportion of the secondary lip is made such that it completely fills the opening 39 with no more clearance than will permit the parts to be readily engaged with each other.

In the secondary fastening section 40 is a bolt aperture or opening 47 which for convenience may be materially larger than the bolt aperture 33 to make certain that the material of the element 30 is concealed beneath the fastening section 31.

Also by way of example only, the curved portion 37 has a recessed inner edge 48 upon which a portion of an outer edge 49 of the secondary lip is adapted to rest, therfiby to provide a reinforced backing of metal for the outer edge of the plastic material.

To further assist in holding the

parts

29 and 30 in proper position, a boss 50 of the plastic material is formed so as to provide a shoulder 51 in a position of abutment with the adjacent recessed inner edge 48. The boss is relatively narrow and has a sloping surface so that it will comfortably clear the outer edge of the frame 16.

When the

elements

29 and 30 are assembled for positioning on a door frame, the secondary lip is slid into the opening 39 where it can neatly adjust itself in position and be contained therein by cooperation of the shoulder 51 and outer edge 49 with the recessed inner edge 48. An edge 52 on the opposite side falls into engagement with the adjacent side of the opening 39 and assists in anchoring the parts in place. In this position the slots 41 will readily align with the screw holes 32 so that screws 42 can be passed therethrough, thereby to anchor the composite assembly to the door frame 16.

While I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent prodnets and methods.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A composite strike plate comprising a metal element including a fastening section having a bolt aperture therethrough, a lip on one edge of the fastening section having a sloping portion extending in a direction oblique relative to the plane of the fastening section and having an inner edge and an outer edge, the sloping portion of said lip having an opening therein located between said inner and outer edge, and a secondary element of synthetic plastic material having a low coefiicient of friction, said secondary element being secured to the metal element at a location over said opening.

2. A composite strike plate comprising a metal element including a fastening section having end edges, an inner edge and an outer edge, said section having a bolt aperture therethrough spaced from said outer edge and providing a relatively flat area therebetween, a lip on the outer edge of the fastening section said lip having an inner edge connected to the outer edge of the fastening section and having an outer edge, said lip having an opening therein between said outer and inner edges and said end edges, and a secondary element of synthetic plastic material having a low coeflicient of friction, said secondary element comprising a secondary lip filling said opening and having an outer surface in a plane above the outer surface of said first identified lip in assembled position, said secondary element being spaced from the latch bolt aperture by said flat area and comprising a latch bolt camming surface, said first identified lip being in engagement with the secondary lip, and at least one shoulder on the underside of said secondary lip having a position of engagement with an outer edge of said opening.

3. A composite strike plate for use with a latch bolt having an oblique camming face and comprising a metal element including a fastening section having a bolt aperture therethrough, a lip on one edge of the fastening section, said lip having the side portion joining the fastening section in substantially the same plane as said section and an opposite camming edge portion obliquely disposed thereto, means forming an opening in the camming edge portion, and a secondary element of synthetic plastic material having a low coefficient of friction anchored in said opening within the camming edge portion, the secondary element having an outer surface thereof at an elevation above the outer surface of the lip whereby to provide a low friction latch bolt striking and camming surface small in area relative to the camming edge portion and in a position adapted to engage said latch bolt progressively along the camming face thereof.

4. A composite strike plate comprising a metal element including a fastening section having a bolt aperture therethrough, a first lip on one edge of the fastening section having an outer edge, said lip having an opening therein spaced from the bolt aperture, and a secondary plate element of synthetic plastic material having a low coefficient of friction, said secondary plate element comprising a secondary fastening section having an outer face underlying said fastening section in assembled position, a secondary lip connected to the secondary fastening section and having a size filling said opening, at least a portion of said secondary lip having an outer surface in a plane above the outer face of said 5 Secondary fastening section in assembled position where- References Cited in the file of this patent by to comprise a latch bolt camming surface, said secondary lip having an outer edge in engagement with the UNITED STATES PATENTS first lip adjacent the outer edge thereof, and a shoulder 851,109 Swift Apr. 23, 1907 on the underside of said secondary lip having a position 5 1,194,636 Joy Aug. 15, 1916 of engagement with an outer edge of said opening. 2,033,079 Lohrs Mar. 3, 1936