US2676825A - Concealed hook latch - Google Patents

Description

. April 27, 1954 R, w. oss 2,676,825

CONCEALEID HOOK LATCH Filed Dec. 5, 1950 r 2 sheets-shank 1 I INVENTOR. RAYMOND W. ROSS BY I ATTORNEYS April 27, 1954 R. w. RYOSS. 2,676,825

CONCEALED HOOK LATCH Filed Dec. 5, 1950 Fi s 2 Sheets-Sheet 2 III/I,

INVENTOR. RAYMOND W. ROSS WM a; M

ATTOR N EYS Patented Apr. 27, 1954 STATES OFFICE 2,676,825 CONCEALED HOOK LATCH Raymo d W'. Russ, Philadelphia, Pa.,' assig to Leeds" and Northrup company; Philadelphia, Pa.; 9; corporatidii of Pennsylvania Application December 5, 1950, Serial No. 1239,27"?

4' Claims. 1

This invention relates to latches for fastening relatively movablememb'ers non, for example, as the lid and case of an instrument housing.

The present invention is particularly suited to housings for portable instruments which must of necessity be moved to various sites. For such housings, this latch is particularly advantageous in that its appearance gives'p'ositive and immediate indication as towhether thehousing' ha's'been set in latched position oi is in unlatched' position. When the movable latching'member and handle elements of the latch occupy, relative to each other, any displacedangular position whatsoever, it will be known that the latch has not been set in its fully latched position, whereas when the handle overlies, conceals and covers the'movable latching member, it will be known that that member has been moved to its fully latched position. Thus, any exposure of the parts'underlying the handle will be indicative of the fact that the latch has not been set-aridthe danger of damage caused by the instrument falling is avoided.

In carrying out the invention, there is provided a latch comprising a pivoted structure and a latchable member, wherein the pivoted structure includes a movable latching member such as a hook and a handle, with pins and cams associated with the hook and handle and'with the base on which the latch is mounted'to control the relativemovement between the hook and the handle; and with the handle overlying the hook and the latchable member to cover the Working members of the latch when in latched position. While the movable latching member is shown'as a hook, it will-be obvious to those skilled in the art that the cooperative relationship between themovable latching member and the stationary latching or latchable member can be provided by serrated or frictionally engaging surfaces rather than by a hooked engagement. I e

For a morecomplete understanding of the invention, reference should'be had to the following description taken in conjunction with the accompan'ying drawingsin which:

Fig. 1 is a perspective view of a box with a hook latch of applicants invention in unlatched position;-

Fig. 2'is a View similar to that of Fig. l with the hook latch in latched position;

Fig. 3 is a rear view of one embodiment-of the latch structure; 7 u v I Fig. 4 is asectionalview along line 4-4 of Fig. 51s a rear view of the embodiment illustratedin Fig. 3, in latched position; I 7 V Fig. 6 is a-rear view of a modi-fication of the embodimentillustratedin Figt 3 Fig. 7 is a rear view oftheg. 6 modification with the latch'i'n itsclosedposition; Y

Fig: 8 is a rear elevation oi anotherhenilaodi ment; with the heck andhandle iifunlatchedpositi'onj Fig. 9 is a rear elevation of the hook and handle of Fig. 8 approaching the latched position;

Fig. 10 is a rear elevation or the hook and handle of Fig. 8 in the latched position; and

Fig. 11 is a sectional view along line l||| of Fig. 10.

It is to be noted that all of the detailed views, Figs. 3, 5, 6, 7, 8, 9, and 10 are rear views, selected because of the covering feature of handle 3. Accordingly, it will be understood that statements of rotation in the clockwise or counterclockwise direction in descriptions of these figures is in the opposite sense to the description that would be given for the same motion when normally viewed from the front of the latch and housing.

Referring now to a front View, Fig. l, the latch is shown attached to the hinged lid I of an instrumentcase 2 of a type carried by a handle afiixed to the lid. The latch 4 is adapted to be swung into engagement with a. latchable member such as shoulder screw 5 attached to case 2. A latch handle 3 has a wide-angle, i. e., about right-angle, relationship with latch or hook member 4 when in the unlatched position. As will later be described in connection with Figs. 3, 6 and 8, this relationship is maintained by frictionally associated and by cam-engaging structures while the hook and handle are swung clockwise. When hook 4" engages screw 5 upon counterclockwise movement of handle 3, the rotary motion of hook 6 is stopped b'ut handle 3 continues to rotate about sha t' 6' and moves relative to hook 4 to a positio'riwhere handle 3 overlies all Working parts of the hook 4 and the latchable member 5.

Fig. 2" showsthe latch in closed position wherein the latched condition is indicated by the comp'le'tefconcealment of all latch part which underlie the" handle. Any motion of the handle 3 will expose some portion of the hook which underlies it, and the exposure of this hook will serve to indicate a departure from the latched position. Further, the cavity in handle 3 receives member 5 and provides a safety-catch action.

Fig. 3sh'ow's a rear View of one embodiment of the pivoted structure used with the structure of Figs. 1 and 2. Handle 3 is mounted on pivot shaft 6" and can be swung freely about axis of shaft 6. Cam 1 is attached to handle 3 and is a circular cam, eccentric to shaft 5 as shown. Hook 4 has'ca'm'surface an associated with cam 1. The surface 4a engages a major fraction of the circumference of can! 1. The remaining associated surface 417 of hook 4 has a larger radius of curvature R which allows clearance radially for retaining or spring member 8. The angular length of'su-riace lib is such as to limit angular displacement of'handle 3 and'hook 4 to Accordingly, hook 4 when in the position illustrated in Fig. 3 will resist movement relative to handle 3, since overlap S frictionally engages hook 4. The resuiting" reaction resists such relative motion and maintains the aforesaid'wide-angle relationship as the handle 3 moves hook 4 toward its latch-em gaging position.

Assume now a movement of handle 3 and hook i in a counterclockwise direction, as viewed in Fig. 3, to a point where hook 4 abuts a latchable member 5. The hook 4 is thus brought to a standstill but continued movement of handle 3 by application of an increased force overcomes the resistance interposed by overlap 9. The resulting relative motion between handle 3 and hook 6 turns cam l in hook d and draws hook 4 up or radially retracts it into latching engagement with member 5. Movement of handle 3 is continued until it overlies hook 4 and receives the latchable member 5 in a cavity provided in the handle 3 as illustrated in Fig. 5. In this final latching position, the handle 3 protects, and, by covering all the working parts of the latch, serves as an indication that the latch has been fully set. It is to be further observed in Fig. 5 that with hook 4 in its latched and radially retracted position the longitudinal axis thereof as well as that of handle 3 are in substantially the same plane.

When it is desired to open the latch, the handle 3 is turned clockwise from the position shown in Fig. 5 about the axis of shaft 6 towards the position shown in Fig. 3. Lip ill on hook 4 prevents hook 4 from following handle 3. The relative movement between handle 3 and hook 4 rotates cam i to move or extend radially hook 4 downward until lip it clears latchable member 5. The handle is then at or near the position where overlap 9 of retaining member 8 abuts the shoulder forming the end of the enlarged radius of surface 41). Hook 4 then swings with handle 3 to the illustrated unlatched position.

As shown in Fig. i, shaft 6 and cam 1 are rigid members attached to handle 3. The shaft 63 extends through lid 1 and is affixed thereto by conventional means, such as spring snap washer ii engaged in a groove 12 in pivot shaft 6 and abutting the inner Wall of lid i. Cam '1 spaces handle 3 a distance away from the front of lid I greater than the thickness of hook member 4. Hook member s is mounted upon cam member I and held close to handle 3 by member 3. With the described arrangement, Figs. 3 and 4, it can be seen that hook 4 swings about shaft 6 and cam i without touching the surfaces of lid l or case 2. In this manner unsightly scratches are avoided. The embodiment of Figs. 3 and i leaves something to be desired in that the frictional engagement between overlap 9 and hook 4 does not give rise to a positive force comparable to one which may be developed by a direct drive between the parts. However, in some applications the direct drive may not be preferred. For such applications, it may be desirable to utilize the arrangement of Figs. 6 and 7 to assure movement of hook t and handle 3 to their Wide-angle relation in the event they should be forced toward their overlapping positions with the hook 4 free of latch member 5. When the latter eventuality occurs, the wide-angle relationship between handle 3 and hook 4 can be readily restored by a pin 28 mounted in lid I, as shown in Figs. 6 and 7, as will now be described. To restore the wide-angle relation between. handle 3 and hook t, handle 3 is rotated in the clockwise direction until hook 4 abuts pin 28. The motion of handle 3 may then be continued, but further movement of hook 4 is prevented by pin 23. When handle 3 reaches the position illustrated in Fig. 6, its motion is also arrested by 4 the abutment of overlap 9 against the shoulder at the end of angular surface 41). It is to be observed pin 28 is located near enough to the pivotal axis to assure concealment of the same by handle 3.

Figs. 8-11 illustrate another embodiment of the invention comprising a simple and rugged structure adapted to production processes and which provides the direct drive for actuating a hook 4 and for controlling its motion relative to the handle 3 both during latching and un latching operations.

In the unlatched position illustrated in Fig. 8. handle 3 and hook 4 are held in the illustrated position by the combined action of a pin 20 mounted in the handle 3, a pivot shaft 6 mounted in handle 3 and turning in lid l, and a pin 22 mounted in lid all associated with their respective cams 2|, 26 and 23 of hook 4. As handle 3 is rotated counterclockwise from the position in Fig. 8, a rotational motion of handle 3 and hook 4 in unison about pivot shaft 6 is the only motion allowed until pin 22 enters the shortradius turn in cam surface 23. Fig. 9 shows the relative position of handle 3 and hook 4 just before pin 22 enters the short-radius turn in cam surface 23. When pin 22 traverses the shortradius turn in cam surface 23 continued motion of handle 3 causes pin 2%, carried by handle 3, to act on cam suriace 2| to move hook 4 upward into latching engagement with member 5 as handle 3 is moved relative to hook 4 into the overlying position illustrated in Fig. 10. It will be noted thatin the cycle of movements from the position of Fig. 8 to that of Fig. 10, the center of rotation for hook 4 shifts from point 24 to point 25 as hook 4 is drawn up into latched position. Pins 2!} and 22 are equidistant from shaft ii, pin 25 being mounted in handle 3 and pin 22 being mounted in lid I.

It will be seen upon examination of Figs. 8, 9, and 10 that cam surface 12! is a short section of are about center 25 with a short aperture at one end; while cam surface 23 is a short section of are about center 24 witha short aperture at the end opposite the short aperture in cam surface 2!. In the cycle of movements from the positions shown in Fig. 8 to those shown in Fig. 10, handle 3 is moved in the counterclockwise direction and, through pin 2?! acting on cam surface 2|, forces hook 4 to rotate with it. Hook 4 begins rotation about point 24 and is shifted so that its point 25 coincides with the center of shaft 6 as hook 4 is drawn upward into latched position by the camming action of pin 2!! moving along cam surface 2!. The counterclockwise motion of handle 3 relative to hookl is stopped in the desired overlying position shown in Fig. 9 by pin 20 abutting the end of cam surface 2|. In Fig. 11 the head of member ii abuts the end of the cavity in handle 3 as pin 20 approaches the end of cam surface 2! thus acting as a stop to accurately position the handle relative to the hook in the closed position. Similarly, hook 4 abuts member 5 and is drawn up into close latching engagement as pin 22 approaches the end of cam surface 23. The design of the modification just described is such that small pins 20 and 22 are not required to transmit large turning or camming forces and are protected from damage.

When the latch of Figs. 8-11 is to be opened, handle 3 is turned clockwise from the position shown in Fig. 10. The pin 20 moves along cam surface 21 until it enters the short-radius portion thereof, camming hook 4 downwardly out of engagement with member 5. The relation of pin 22 in cam slot 23 is such that hook 4 is moved downwardly before permitting any rotation thereof. As the motion of handle 3 is continued in the clockwise direction, pin 20 rotates hook 4, the fixed relationship characteristic of the unlatched position shown in Fig. 8 being maintained by the action of pin 22 in cam slot 23. Handle 3 and hook 4 then continue to rotate in this fixed relative position until the position illustrated in Fig. 8 is reached. At this point pin 22 abuts the end of cam surface 23, and both the hook and the handle are arrested in that position.

While preferred embodiments of the lock have been shown, it will be obvious to those skilled in the art that other arrangements of cam and friction members maybe utilized in accordance with applicant's teachings without departing from the scope of this invention as set forth in the appended claims.

What is claimed is:

1. A hook latch for a stationary latching member comprising a pivot shaft, a hook member car ried by said shaft and relatively rotatable about its axis and movable transversely with respect thereto, an actuating handle having dimensions of length and breadth relative to those of said hook member for forming a concealing cover for said hook member when the handle is moved to a latching position with its longitudinal axis in alignment with that of said member, said handle having a recess formed on an underside adjacent an end thereof for receiving the latching member, said pivot shaft being secured to and extending outwardly and away from the underside of said handle adjacent an end portion thereof, and cam surfaces movable by said handle and having shapes which upon rotation of said handle from an unlatching position to said latching position move said hook member transversely of the axis of said shaft, said handle at the completion of said latching movement overlying and covering the length and breadth of said hook member and disposed in covering relationship over the latching member to indicate the completion of the latching operation.

2. A hook latch for a stationary latching member comprising a pivot shaft, a hook member carried by said shaft and relatively rotatable about its axis and movable transversely with respect thereto, an actuating handle having dimensions of length and breadth relative to those of said hook member for forming a concealing cover for said hook member when the handle is moved to a latching position with its longitudinal axis in alignment with that of said member, said handle having a recess formed on an underside adjacent an end thereof for receiving the stationary latching member, said pivot shaft being secured to and extending outwardly and away from the underside of said handle adjacent an end portion thereof, cam surfaces movable by said handle and having shapes which upon rotation of said handle from an unlatching position to said latching position move said hook member transversely of the axis of said shaft, and a spring member disposed between said movable hook member and said handle for developing a frictional drive therebetween while they are in wide angled relationship, said handle at the completion of said latching movement overlying and covering the length and breadth of said hook member and disposed in covering relationship over the latching member to indicate the completion of the latching operation.

3. In combination, a hook member adapted to be rotated and radially extended and retracted with respect to a stationary latching member, movable cam surfaces, and an actuating handle having dimensions of length and breadth re1ative to those of said hook member for forming a concealing cover for said hook member when the handle is moved to a latching position with its longitudinal axis in alignment with that of said member comprising a pivot shaft secured to and extending outwardly and away from the under surface of said handle adjacent an end portion thereof, said handle having a recess formed on the under surface adjacent said hook member extending from one side thereof toward but terminating short of the other side thereof and adapted to receive the stationary latching member, said cam surfaces being movable by said handle and having shapes which upon rotation of said handle from an unlatching position to a latching position move said hook member in a direction along its longitudinal axis for engaging the stationary member, the rotation of said handle being limited upon completion of the latching movement by a wall of the recess, said handle upon the completion of the latching movement overlying and covering the length and breadth of said hook member and disposed in covering relationship over the latching member to indicate the completion of the latching operation.

4. A hook latch for a stationary latching member comprising a pivot shaft, a hook member carried by said shaft and relatively rotatable about its axis and movable transversely with respect thereto, an actuating handle having dimensions of length and breadth relative to those of said hook member for forming a concealing cover for said hook member when the handle is moved to a latching position with its longitudinal axis in alignment with that of said member, said pivot shaft being secured to and extending outwardly and away from the underside of said handle adjacent an end portion thereof, a first cam surface on the underside of said handle and eccentric with said pivot shaft, a second cam surface on said hook member for engaging a major portion of said first cam surface, said second cam surface having an offset arcuate surface spaced from said first cam surface, and a spring member disposed between said movable hook member and said handle and passing through the space between said offset surface and said first cam sur face for developing a frictional drive between said handle and hook member while they are in wide angle relationship, said cam surfaces movable by said handle and having shapes which upon rotation of said handle from an unlatched position to said latched position move said hook member transversely of the axis of said shaft, said handle at the completion of said latching movement overlying and covering the length and breadth of said hook member and disposed in covering relationship over the latching member and cam surfaces to indicate the completion of the latching operation.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 567,620 Smith Sept. 15, 1896 685,469 Hasenpflug Oct. 29. 1901 1,517,995 Langenau et a1 Dec. 2, 1924 2,151,219 Madsen Mar. 21, 1939 2,514,980 Vincent July 11, 1950

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