Latch with spring

Details Latch with spring Latch with spring

1999-10-13

2001-07-31

Wilson, Neill (Department: 3627)

Expanded, threaded, driven, headed, tool-deformed, or locked-thr

Headed fastener element with nut, washer, securing means or cap

Headed fastener element with securing means and biasing spring

C411S549000, C411S553000

Reexamination Certificate

active

06267543

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to fasteners for removably securing together two panels or other objects. More particularly, the present invention relates to a quarter-turn panel fastener having a spring.
BACKGROUND OF THE INVENTION
Many types of fasteners are used to removably attach one panel to another. Often, sheet metal screws or machine screws, with or without nuts, are used for these tasks. Although these screw type fasteners will securely fasten one panel to another and are readily unfastened, they are inadequate for many applications. For instance, screw type fasteners take too long to assemble and disassemble, require relatively precise tolerances in panel fit, and are subject to cross-threading, stripping, and under- or over-tightening. There is a need for fasteners that are quick and easy to use, and that positively engage. This is particularly true in light industrial applications such as the computer industry, where it is desired to attach various loose-fitting components and covers in a positive secure fashion that allows such covers and components to be easily installed and removed.
Quarter-turn latches are used for latching a variety of cabinets, doors and other enclosures. It has been suggested to construct a quarter-turn fastener as shown in
FIG. 1. A
bolt
1
has a disk-shaped head
2
and a cylindrical shank
3
. Two projecting keys
4
,
5
project radially outward from the shank
3
opposite one another. A keyhole
6
, shown in
FIG. 2
, is made in each panel
10
,
11
to be adjoined. The keyhole
6
consists of a circular hole
7
with two radially extending rectangular slots
8
,
9
opposite one another. In operation, the top panel
10
is placed over the bottom panel
11
with the keyhole in each panel aligned. The bolt
1
is guided through the panels
10
,
11
and the keys
4
,
5
simultaneously pass through the slots
8
,
9
.
The bolt is twisted 90°, placing the keys
4
,
5
in the positions
12
,
13
shown by dotted lines in
FIG. 2
, effectively locking the panels
10
,
11
together. A coil spring
14
coaxially surrounds the shank
3
and is compressed between the bolt head
2
and the top panel
10
. The compressed spring
14
pulls the keys
4
,
5
against the underside of the bottom panel
11
, holding the bolt
1
in position by friction. Thus, the spring
14
provides a compressive biasing force that pulls the panels
10
,
11
together for positive engagement and to avoid rattles.
Drawbacks exist with many quarter-turn latches. For instance, they can be susceptible to operator error. Without positive engagement, the operator can turn the bolt too far, or not far enough. The bolt can rotate to the unlocked position due to vibration. In addition, the coil spring adds purchase and assembly costs, and can be lost. Consequently, there is a need for a quarter-turn fastener which is simple, inexpensive, requires a minimum number of parts, and provides positive engagement.
SUMMARY OF THE INVENTION
The present invention relates to a fastener system for fastening a first panel in which is formed a first keyhole to a second panel in which is formed a second keyhole. According to one aspect of the invention, the fastener system includes a bolt with a head, a spring member integrally formed with the head, a shank, and a first key attached to the shank opposite the head. The bolt passes through the first keyhole and the second keyhole, when the first key is aligned with a first slot in the first keyhole and a second slot in the second keyhole. The bolt is rotatable from an open position where the first key is aligned with the first slot and the second slot, to a closed position where the first key bears against a back surface of the second panel. The spring cooperates with the first key to bias the first panel to the second panel.
In a preferred embodiment of the invention, an annular track is located on the back surface of the second panel and slopes to a crest and recedes to a landing area. The first key is retained in the landing area by the biasing force of the spring member. An open bump stop is located on the back surface of the second panel adjacent the first slot portion and is engageable with the first key when the bolt is in the open position. A closed bump stop is located on the back surface of the second panel adjacent the landing area and is engageable with the first key when the bolt is in the closed position.
The bolt may have a second key located on its shank between the head and the first key. In a preferred embodiment of the present invention, the second key fits through the first slot in the first panel and engages a back surface of the first panel when the bolt is rotated away from the entry position of the second key in the first slot. The second panel may be recessed away from the first panel to provide room for the second key.
The present invention should not be limited to the preferred embodiments shown and described in detail herein. The above and other advantages and features of the invention will be more readily understood from the following detailed description and the accompanying drawings.


REFERENCES:
patent: Re. 30801 (1981-11-01), Gley
patent: 2368799 (1945-02-01), Barlow
patent: 3169293 (1965-02-01), Neuschotz
patent: 4007516 (1977-02-01), Coules
patent: 4212560 (1980-07-01), Pufpaff et al.
patent: 4262394 (1981-04-01), Wright
patent: 4391461 (1983-07-01), Deibele
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patent: 4893978 (1990-01-01), Frano
patent: 5052849 (1991-10-01), Zwart
patent: 5123795 (1992-06-01), Engel et al.
patent: 5370488 (1994-12-01), Sykes
patent: 5509703 (1996-04-01), Lau et al.
patent: 5630632 (1997-05-01), Swan
patent: 1136662 (1968-12-01), None

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