US2095671A

US2095671A - Door latch

Info

Publication number: US2095671A
Application number: US58338A
Authority: US
Inventors: William C Mcwhirter
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1936-01-09
Filing date: 1936-01-09
Publication date: 1937-10-12
Anticipated expiration: 1954-10-12

Description

Oct. 12, 1937. w. c. MCWHIRTER DOOR LATCH Filed Jan. 9, 1936 2 Sheets-Sheet l INVENTOR y William CMQWZZL'PAQP.

Q/KW [S ATTORNEY W. C. M WHIRTER DOOR LATCH 2 Sheets-Sheet 2 Oct. 12, 1937.

Filed Jan. 9, 1956 vi) a w I I I n I I! II E) I I I I I N N} I like I I, I (o I INVENTOR WLllLam CMQWZIIPL QP Q Rum HIS ATTORNEY Patented Oct. 12, 1937 Application January 9, 1936, Serial No. 58,338

2 Claims.

My invention relates to door latches, and particularly to door latches which are suitable for latching the doors of pressed steel cabinets and the like in one or more open positions.

One object of my invention is to provide a door 1atch which will automatically latch a door in a predetermined open position when it is moved in one direction to such position but which will permit the door to remain unlatched when it is moved in the opposite direction past such open position.

Another object of my invention is to provide a door latch of the type described which is inexpensive to manufacture and install, and which when installed gives minimum interference with apparatus in the cabinet.

I will describe one form of door latch embodying my invention, and will then point out the novel features thereof in claims. c

In the accompanying drawings, Fig. 1 is a front elevational view showing a pressed steel cabinet provided with a door latch embodying my invention, the door being rotated from its closed position and a portion of the cabinet and the door being broken away or removed to better illustrate the construction of the latch. Fig. 2 is a sectional view of a portion of the cabinet illustrated in Fig. 1 taken above the door latch, the door of the cabinet being shown in its closed position and certain of the parts being broken away to better illustrate the construction of the latch. Fig. 3 is a fragmentary sectional view similar to Fig. 2 showing the door latch embodying my invention on an enlarged.- scale, the parts being shown in full lines in the positions which they occupy when the door is rotated from its closed position, and in dot and dash lines in the positions which they occupy when the door is rotated 90 from its closed position. Fig. 4 is a sectional view taken on the line IVIV of Fig. 3.

Similar reference characters refer to similar parts in each of the several views.

Referring to the drawings, a door latch embodying my invention is here shown applied to the door I of a pressed steel cabinet 2, but it should be particularly pointed out that my invention is of general utility, and may be used wherever it is found to be advantageous. The door l is secured to the cabinet proper by means of hinges 3, and is free toswing from its closed position through an angle of substantially The door latch comprises, in general, a bracket 4, a link 5, and a latch plate ii. The bracket t is provided with a vertical portion 4 which is welded to the upper part of the door I in the position shown, and with a horizontal portion i having an upstanding pin 1 secured thereto as by riveting.

The link 5 is provided at one end with a hole 5 which receives the pin i with suiiicient clearance to permit the link to move vertically through a short distance, and at the other end with a screw-threaded hole 5 which receives the lower end of an upstanding stud 6. The link 5 is retained on the pin i by means of a cotter key 5 which passes through a suitable hole provided in the upper end of the pin above the link.

The stud i3 is locked in an adjusted position in the hole 5 by means of a jam nut l0, and is provided at its upper end with an enlarged shank portion 3 and with a disk-shaped head 8 As best seen in Fig. 4, the enlarged shank portion 8 is formed with a tapered lower portion 8, and is somewhat smaller in diameter than the head 8*.

The latch plate 6 is secured as by welding to an inwardiy extending portion of the door jam of the cabinet 2 above the door I, and is provided with a longitudinally extending slot '3 which slidably receives the stud 8 in such mannor that movement of the door will cause the stud to move along the slot to different positions. The link 5 and stud 8 are biased by gravity to a position in which the enlarged shank portion 8 of the stud 8 tends to enter the slot 6*, but this slot is made narrower than the enlarged shank portion 3 except at two enlarged

portions

6 and 5 which are formed in the slot at the positions which the stud occupies when the door is swung 99 and 170, respectively, from its closed position, and these enlarged portions of the slot are of such size and shape that the enlarged shank portion of the stud will drop into either enlarged portion of the slot when and only when the stud is centrally located with respect to such enlarged slot portion. It will be apparent that when the enlarged shank portion of the stud enters either enlarged portion of the slot, the door I will then be latched in the corresponding position, and will subsequently remain latched in this position until the link and stud are manually raised to remove the enlarged shank portion of the stud from the enlarged portion of the slot.

The door latch also comprises two guides l2 and H which are secured to the latch plate 6 on opposite sides of the slot 5*, and which cooperate with the enlarged head 8 of the stud 8 in such manner that when the door I is moved I from its closed position to either its 90 or 170 open position the stud will be held in the proper position to cause the enlarged shank portion of the stud to automatically drop into' the enlarged

slot portion

6 or 6, as the case may be, but that, when the door is moved toward its closed position past its 90 open position, the stud will be permitted to move rearwardly, due to the thrust on the link 5, to a position in which the tapered lower end of the enlarged shank portion will ride on the latch plate 6 in such manner that the enlarged shank portion will be prevented from entering the enlarged portion 6* of the slot.

It will be-seen, therefore, that with the latch constructed in accordance with my. invention, when the door I is opened to either its 90 position or its 170 position, the door will automatically become latched in such position unless the link 5 is manually held in its upper position, but that, when the door is moved toward its closed position past its 90 'open position, the angular disposition of the parts will cause the tapered lower end of the enlarged shank portion of the stud to cooperate with the latch plate at the rear edge of the slot in such manner that the enlarged'shank portion of the stud will be prevented from dropping to its latching position, with the result that in operating the door from its full open to its full closed position, no latching action will result. The position which the parts occupy when the door is latched in its 170 posi tion is shown in full lines in Fig. 3, and the posi tions which the parts occupy when the door is latched in its 90 open position are shown in full lines in Fig. l and in dot and dash lines in Fig. 3,

while the positions which the parts occupy when the door is closed are shown in Fig. 2.

A stop I3 is secured to the link 5 intermediate its ends, and this stop cooperates with the door at point l in the manner shown in Fig. 3 to prevent the door from being rotated more than 170 from its closed position.

larged shank portion, a fixed latch plate having It should be particularly pointed out that while in describing my invention I have shown the latch constructed in such manner that it' will latch the door in only two open positions, by providing the slot 6 with additional enlarged portions similar to the enlarged

portions

6 and 6, the door latch may be made to latch the door in a plurality of other open positions as will be readily understood from the foregoing description and from an inspection of the drawings.

Although I' have herein shown and described only one form of door latch embodying my invention, it is understood that various changes and .modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A door latch comprising a link pivotally attached at one end to the door and provided at the other end with an enlarged shank portion and with a head which is larger than said ena slot which slidably receives said stud and which is provided with an enlarged portion at the position said stud occupies when said door is moved to a predetermined open position .and which is narrower in width than the diameter of said enlarged shank portion of said stud except at said enlarged portion of said slot, said link and said stud being biased to such positions that said enlarged shank portion of said stud will automatically enter said enlarged portion of said slot when said two enlarged portions are in axial alignment, and the parts being so disposed that said stud will tend to remain out of axial alignment with said enlarged portion of said slot during movement of said door past said predetermined open position, and a guide cooperating with the head of said stud to cause said stud to align axially with said enlarged portion of said slot when said door is moved in one direction to said predetermined open position.

2. A door latch comprising a link pivotally attached at one end to the door and provided at the other end with an enlarged shank portion having a tapered lower portion and with a head which is larger than said enlarged shank portion, a fixed latch plate having a slot which slidably receives said stud and provided with an enlarged portion at the position said stud occupies when the door is moved to its full open position and with another enlarged portion at. the position said stud occupies when the door is moved to an intermediate open position, said link and said stud being biased to such positions that said enlarged shank portion of said stud tends to enter said slot and the parts being so proportioned that said enlarged shank portion is prevented from entering said slot except when said stud is centrally located in one or the other of the enlarged portions of said slot and that said stud will tend to move to a position in which the tapered lower portion of the enlarged shank portion will ride on the latch plate at one side of the slot when the door is moved from its closed toward its open position and at the other side of the slot when the door is moved from its open toward its closed position, and two guides secured to said latch plate on opposite sides of said slot and cooperating with the head of said stud in such manner that said stud will be guided to the proper position to enter either enlarged portion of the slot when the door is moved from its closed position to the corresponding open position but that when the door is moved toward its closed position past its intermediate open position said stud will be permitted to move to the position in which the tapered lower portion of said enlarged shank portion rides on said latch plate at the edge of said slot, whereby the door will become automatically latched in its intermediate and full open positions when moved to these positions from its closed position but will remain unlatched during movement of the door toward its closed position past its intermediate open position.

WILLIAM C. MCWHIRTER.