US2328552A - Mechanical movement - Google Patents

Description

Sept. 7, 1943. 1... F. HAMMAND MECHANICAL MOVEMENT Original Filed Nov. 18, 1941 AWN W LfHa ppayd Patented Sept. 7, 1943 UNITED STATES PATENT OFFICE Divided and this application March 21, 1942, Serial No. 435,724

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) Claims.

The invention described herein, if patented, may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The present invention relates to mechanical movements such as latching devices, and more particularly to a simple and novel arrangement of parts whereby relatively great loads may be securely latched against accidental release, yet positively released in response to latch-actuating forces of extremely small magnitude.

In most conventional latch structures, latching surfaces are provided that frictionally engage each other and prevent relative movement between stationary and movable parts of the mechanism. In all well known structures of this character the force required to cause the latch to release is more or less proportionate to the magnitude of the load acting on the latch surfaces, that is, the greater pressure that exists on th latch surfaces, the greater the friction between these surfaces, and the larger the force that will be required to effect release.

It has long been one aim of machine designers to provide a simple type of latching structure arranged to sustain the load of a great weight or heavy spring pressure and yet so designed and constructed that it was capable of positive and unfailing release operation in response to very small forces.

The utility of a satisfactory device of this character should be entirely obvious since any device that reduces the operating force required to release a latch structure will necessarily improve the operating characteristics of any mechanism including a latch arranged to be actuated by small forces.

The latch comprising the subject matter of the present invention is shown and described in connection with a gasoline dispensing nozzle and is associated with the nozzle in such a manner that the heavy load of the valve actuating spring may be positively controlled by slight fluctuations in atmospheric pressure in a diaphragm control system, and while such an arrangement is well adapted to illustrate the utility of and the necessity for a latching device as disclosed in this application, it should be understood that the nozzle structure is described by way of illustration rather than by way of limitation and that the teachings of the present invention are equally applicable throughout the entire field of mechanics and in connection with any device having a heavy load to be released by comparatively minute forces.

A primary object of the present invention is to provide a novel and improved mechanical movement constituting a latching structure adapted to maintain itself against a relatively great load and to release said load in response to forces of extremely small magnitude.

A further object of the invention is to provide a latching mechanism constituting a series of latches wherein the primary latch maintains the mechanism against release and a secondary latch prevents release of the first, the arrangement being such that the primary latch is unstable in that it is not self-maintaining and will automatically release unless maintained in position by the secondary latch.

A further object of the invention is to provide a series of latches including a primary unstable latch and a secondary latch together with forcereduction levers whereby the secondary latch has a mechanical advantage over the primary and whereby the latch actuating means has a mechanical advantage over the secondary latch.

A further object of the invention is to provide a mechanical movement including a series of latches having an unstable primary latch in combination with a secondary latch and actuating means for the primary latch arranged to concurrently release the primary latch and apply force to assist in its releasing movement.

A still further object of the invention is to provide a mechanical latching mechanism of the type described including a relatively few parts of rugged construction and simple mechanical operation and adapted to economical methods of manufacture.

The present application is a division of my 00- pending application, Serial No. 419,525, filed November 18, 1941, and, while the claims of this application will be limited to the features of the mechanical movement used as a latching device in the parent application, it is believed desirable to fully illustrate the gasoline dispensing nozzle structure of the parent case, in order to give a clear understanding of one adaptation of the present claimed invention. It should be noted, however, that this cas is directed to a mechanical movement that is by no means limited in utility to gasoline dispensing equipment, but which is of broader scope, and extends to any one of the various fields of mechanics in which latching structures are used.

Referring now more particularly to the draw- Fig. 1 is a longitudinal sectional view of a gasoline dispensing nozzle having a latching device constructed in accordance with the teachings of the present invention, and

Fig. 2 is a fragmental longitudinal sectional view of a modified form of the invention.

The nozzle structure illustrated includes a valve housing or body portion generally indicated at iii. The valve body lo has a tubular handle portion 3! including an inlet passageway and a neck portion 53 including an outlet passageway i having a restricted Venturi section l5 and terminating in a forward end constituting a mounting collar 53 for the dispensing spout ll. The valve body is provided with a valve seat interconnecting the inlet passageway i2 with the outlet passageway Hi. The valve seat 22 is closed by a valve 22 having a valve stem 23 arranged to extend exteriorly of the valve body ill so that the lower extremity 24 of the valve stern will be outside of the valve body and adapted for manual actuation. Preferably, a gland or other suitable sealing structure (not shown) is arranged to be tightened around the stem 23 by means of the sealing cap 25. Thevalve 22 is normally forced into firm engagement with the valve seat M by a relatively heavy coiled compression spring 2&3 having its upper end supported by the threaded closure cap 27 and having its lower end bearing directly against the valve 22. The closure cap 2'! is threaded into the valve body and is preferably provided with a sealing gasket 28 and drilled at 29 to provide a guide for the upper end of the valve stem. It is contemplated that the valve 22 is to be opened manually, and to this end a valve operating lever 32 is pivoted on a supporting pivot 33 positioned somewhat forwardly of the lower extremity Ell of the valve stem. The valve operating lever 32 is offset at M so that the handle portion remote from the supporting pivot will lie substantially parallel with the handle portion l I of the valve body, so that the operator may grasp the handle H and the valve handle 32 in one hand and open the valve by drawing the lever 32 toward the valve body. The actuating lever 32 is protected against accidental opening or damage by a lever guard 35 secured .to the end of the handle portion H by any convenient means, and including a relatively straight portion Bl spaced apart from the valve body and extending forwardly in a position more or less parallel with the handle portion H. The forward curved end 38 of the handle guard is arranged to be secured to the lower side of the valve neck It by a plurality of cap screws (not shown), which extend through the flange 3". The for ward portion of the handle guard 35 is provided with a pair of relatively wide side walls 4i spaced apartfrom each other to define a cavity 42 in the forward portion of the valve guard in front of the Valve stem and below the neck l3 and outlet passageway 24 for the purposes to be hereinafter described.

The lower portion of the forwardly extending neck i3 of the valve body is widened to provide a rarified air chamber 45 over which a flexible fabric diaphragm 46 is clamped by a suitable flange ll. The diaphragm 45 may be of any resilient material but is preferably formed of multiple thicknesses of thin cloth treated in such a, manner as to make it impervious to air and commonly known in the trade as airplane cloth. The diaphragm 58 is circular in shape so that it entirely closes the lower side of the aperture d5. It is provided with a pair of center plates $8 to reinforce the fabric diaphragm and to provide a mounting for a post to which the latch release mechanism is attached.

The rarified air cavity 125 is interconnected with the venturi iii by suction ports 5t and 5! so that the flow of liquid through the discharge passageway of the nozzle will withdraw some of the air from the air chamber 25 of the valve body. When the device is in use, the air sucked from the chamber through the suction ports will be replaced by air entering the side port of the nozzle spout ll,

In the present structure, the port Si is plugged at its rear end by the tapered plug and communication with the interior of the chamber lli is established by the port it extending angularly from the port iii to a point adjacent the lower forward edge of the diaphragm With this arrangement the suction action of the Venturi tube IE will remove any accumulation of liquid gasoline within the chamber so that any quantities of gasoline drawn upwardly through the tube 58 will be immediately ejected through the ports Strand 5! and into the stream of liquid, in order that the passageways will always be open for the free venting of air to the cha. ber 45.

The air from the port enters through the orifice 53 in the block secured on the inner circumference of the spout, and passes thence through the vent tube 55 which extends upwardly through the spout ii and communicates with the air chamber 45 through the air inlet port 5d, The block 5t is provided with an annular valve seat 55 and a screw-threaded adjusting screw 55 is arranged with a needle valve 5%"! adapted to be adjustably moved toward the valve seat to proide an adjustment for the restriction of the vent passageway. It will be noted that the block '54 is positioned entirely within the nozzle spout ll and is therefore entirely protected against accidental screw parallel with the axis of the nozzle spout and may be easily reached by inserting a screw driver in the open lower end of the spout. By this arrangement, the restriction of the air inlet to the cavity 45 may be adjusted so that the device will be readily responsive to specified changes in pressure.

The subject matter claimed in the present application resides in the features of the mechanical movement associated with the supporting pivot 33 on which the valve control handle is mounted, in order that the relatively small atmospheric force actuating the shut-off diaphragm may be utilized to release the comparatively large force of the coiled compression spring and force the valve 22 intoclosed position. To accomplish this result, the valve pivot pin is mounted in a pair of slots pro-v C1. in eachof the side walls of the link ge cavity 42. These slots 5! act as guides for the supporting pivot 33 so that when it is not maintained by mechanism hereinafter described, the forward end of the valve operating le'e'r may snap outwardly responsive to the outward force of valve stem, so that the valve 22 will be in closed position notwithstanding the fact that the re r .end of the valve operating le' 1' 32 is moved the handle portion ii of the valve body.

The supporting pivot 33 also extends through a shiftable pivot retainer 52 adapted to partially encircle a roller .53 rotatably mounted on the cross pin 64 extending between the two side walls 4! of the linkage cavity 42. The upper end of the pivot retainer 62 includes a latching surface 65 arranged to engage and be secured by a latching surface 66 formed on the latch releaselever 61. The lever 61 is pivotally mounted on a stationary pivot 68 extending between the walls 4| of the linkage cavity 42 and has its outer end pivotally mounted on the diaphragm post 48 by a pivot pin 69. The pin 69 also carries one end of a coiled compression spring H which extends downwardly and has its lower end secured to a side projection 13 formed on the latch retainer 62. The curved surface 14 of the latch retainer 62 partially encircles the roller 63 to provide an unstable roller type latch, the arrangement being such that while the roller 63 and its mounting pin 64 restrain the supporting pivot 33 against downward movement in the slot 6|, yet the angle of engagement between the roller 63 and the curved surface 14 of the latch retainer is such that the force of the compression spring 26 will exert a. definite bias on the latch retainer, tending to move it to the right as viewed in the drawing, unless this movement is prevented by some outside means. It will be understood, however, that the magnitude of the force tending to bias the latch to released position will be very'small as compared with the force exerted by the spring 26.

The upper extension of the latch retainer constitutes, in efiect, a lever with the supporting pivot 33 as a fulcrum and with the force acting at the curved surface 14, so that the upper portion 65 of the lever will have a definite mechanical advantageover the latching surfaces 14 and so that the force tending to bias the latch retainer 62 toward released position may be readily overcome by a very light force at the upper end 65 of the latch retainer. Thus, the effective pressure between the latching surfaces 65 and 66 will be extremely small and the latching may be easily released by the operation of the diaphragm 46 even though the pressure differential on the opposite sides of the diaphragm is comparatively small.

The operation of the device is as follows:

The normal position of all parts of the structure is as shown in Fig. l of the drawing and, to operate the device, the operator will grasp the nozzle by the handle portion H and draw the rear end of the valve-operating lever 32 inwardly to bear against the lower portion 24 of the valve stem and raise the valve 22 from the seat. The liquid will then be free to flow through the passageway I2 into the passageway l4 through the Venturi tube l and outwardly through the nozzle spout l1 and into the container. During this time the action of the Venturi tube l5 will withdraw air from the air chamber 45, but inasmuch as the air chamber 45 is vented through the air inlet 52 and vent tube 58, the pressure within the air chamber 45 will not be substantially reduced and the diaphragm 46 will not be caused to operate. However, when the level of the liquid in the container being filled rises to a point above the end of the spout I1, the liquid will close the orifice 52 or the restricted needle valve 51 and, since the flow of liquid through therestricted orifice will be far less than the flow of air through the same orifice, the vent 58 will be, to all intents and purposes, closed by the rising level of the liquid. When this occurs, the continued action of the Venturi tube [5 will continue to withdraw air through the suction ports 56 and 5| and cause a substantial reduction of pressure in the air chamber 45 so that the atmospheric pressure of the surrounding air (which is in communication; with the lower surface of the diaphragm 46 through the linkage cavity 42) will force the diaphragm 46 upwardly against the comparatively light resistance of the spring H. The cros pin 68 acts as a pivot for the anchored end or the pressure reduction lever 61, so that when the outer end of the lever 61 is drawn upwardly, the latching notch 66 is disengaged from the upper end 65 of the retainer 62. It will be noted, in passing, that the latching notch 66 is positioned at a point less than half of the distance between the pivot pin 68 and the diaphragm post pivot 69 so that the movement of the diaphragm has a decided mechanical advantage over the latching surfaces and a very small effort on the diaphragm is suflicient to overcome the friction incident to the engagement of the latch, so that the release operation of th mechanism will be entirely positive, notwithstanding the fact that the pressure differential on the opposite sides of the diaphragm may be rather small.

When the latch 66 disengages the upper end of the retainer 62, the force of the coiled compression spring 26 of the main valve 22 will act on the unstable-latch 63-14 to release the pivot 33 and snap it to the lower end of the guide slots 6| to close the valve. This action will be readily understood when it is recalled that the latch 63l4 is unstable. Thus, when the lever 32 is operated, the force of the compression spring 26 will urge the supporting pivot 33 downwardly in the slot 6! and will tend to bias the latch toward its released position. It will be understood, of course, that the force tending to bias the latch to its released position will be extremely small as compared to the total force of the spring 26, but it will nevertheless permit the mechanism to release when the secondary latch 65--66 is disengaged. As this operation takes place, it is obvious that the spring 26 will instantly close the valve 22 and shut off the flow of liquid in time to prevent the container being filled from overflowing.

When the flow of liquid through the Venturi tube [5 is discontinued, the pressure on the opposite sides of the diaphragm 45 will automatically equalize, and the spring H will draw the diaphragm 46 outwardly and downwardly to the position illustrated in Fig. 1.

On release of the lever 32 the coiled spring II will draw the latch retainer 62 upwardly and, inasmuch as the outer extension 13 cf the latch retainer 62 is a considerable distance from the pivot 33, the spring will tend to move the upper end 65 of the retainer inwardly to the left until it engages the notch 66, at which time the spring II will move the lever downwardly so that the notch will prevent return movement of the latch 65; thus, the single spring I! serves the multiple functions of drawing the diaphragm downwardly, returning the latch66 to position, drawing the pivot 33 and latch retainer upwardly and swinging the pivot latch retainer 62 to the left about the pivot 33 to cause engagement of the latched surfaces 65 and 66. In this manner the single spring ll comprises spring means for ac complishing four separate functions, though it will be understood that it is a matter of simple mechanical skill to provide separate springs to accomplish each of the aforementioned functions.

The device illustrated in Fig. 2 is similar to that shown in Fig. 1 with the exception that the latch retainer 8| is provided with a latching surface 82: comprising an inclined! cam surface. at an obtuse angle. with respect to the direction. or release movement of the: latch; and the. latching surface 82 is arranged to; engage. aninclincd cam surface 83TO1'1 a stationary latch block 8. T. This.

structure constitutes an. unstable; latch wherein a. downward. force onlthelatcb; pivot. 33 willtcnd to bias. the. retainer. toward its; released; position and. will. release the latch unless otherwise so.- cured. The upper end; of the latch: is otherwise secured; however; by the latching engagement between the; inclined cam surface 8.5; of the latch retainer and a. corresponding: inclined cam surrfiace. 8,6 of the latch lever: 81' mounted on the cross pivot 88. inner end: of; the lever 81 is; mounted for; pivotal movement on a. pin. as extending between the. side Walls; 41 of; the; lin 1.- agecavity and. the; outer end of the lever is connected to: the, diaphragm post 48 by a pivot pin 89; In this construction, it Will benoted that the primarylatch comprising the; latch surfaces 82 and 83 cooperate to form an unstable latch which will be. biased toward released position and will release unless maintained: by an. external force, and that the-secondary latching; surfaces 85 and 86" are similarly arranged. Accidental release-of the secondary latch is prevented, hawever, by a light coiled: compression spring 91 positioned within the air chamber 45- and, arranged to urge thediaphragm 46 and. lever 81 downwardly. The arrangement is: such that, the spring BL is. sufficient toovercome; the extremely small force-tending to bias the latch asset. to released position and. the unstable. oharacteristicsof this latch only tend; to provide: forv easy a and. positive. release whenever the pressure diiferential on the.- diaphragm ii-becomes sufficient to overcome the downward force; of the spring, 94.

A return spring; 92 is mounted on. the. cross pin 9-3 and secured to or sidepirr 94 on thewla-tch retaining element 8d: and. is arranged to lift the supporting pivotv 33. to returnitto'the upper end of. the slot when the handle is released. and to exert a counterclockwise urge on the latch. r-e= tai-ner 8|. causing it to engage the: latching: surface. 82 above the inclined cam. surface 8.3 and causing itsupper end to move-beyond the latching surface 86 so that the return. movement is effectuallyprevented.

It has been previously mentioned that the latching. structures 63-142 and 82-83.. are, arranged that they are biased toward released po-.- sition by the force. of the spring; 25.. It, is desirable' that the magnitude of the force component acting as a bias be quite small in order that. the; friction incident to. the release of the secondary latches be as. small. as. possible,. but it will also be appreciated that if it. is toosinall. the friction between. the cooperating. surfaces ofithe primary; latch may.- cause the latch. to fail. to re.- 18386.

In the present invention, means are provided whereby the cooperating surfaces of theprimary latchesmay be unfailinglyreleascd even though shaped to resolve theforce, of the spring 25. into a biasingforce offar less magnitudethan. would be requircdby the structure heretoforedescribed. Thisdesirable object is accomplished bythehovcl combination of the. structure heretofore described and a latch. actuator mechanism-,tmactlvely force the primary latch to release concurrently with the release of the secondary latch. For this-purpose the lever. 61' is providedwith a short latch actuator or-push-off: armlfi so; thatasathelatch 65-66.: is rel'eascdithc: actuator- 15. will:- strike. the

upper end 65 or the. retainer and actively urge the.- primary latch. 63-14 to. release. In; the structure illustrated in. Fig.2, the lever 3:7; is pro.- vided with ashort: latch. actuator 15 adaptedto function in. an identical manner.

Bythis. arrangement it is entirely feasible-v to shape. the. surfaces. of the. primary latch to exert a. bias. force. that is. almost, but not quite, sum.- cient. to. overcomethe friction, of the latching surfaces and cause. the. primary latch to; release. This; will. mean that there will. be noeifjective force; acting between the secondary latch. surfaces, so: these. willrelease without friction, and since the primary latch. is: already biased to. release, it will require only a touch. from. the ac.- tuator.

From: the foregoing, it will be; apparent. that by following the teachings of the present invention, a novel and improved mechanical latch movement may be provided whereby the release of relatively great forces, such as exerted by the load of the heavy shut-oilv valve. spring; may be positively controlled by a simple, rugged. mechanismadapted to be operated by a-comparatively minute effort.

It wi-llalso be seen that the, mechanical movement here disclosed is well suited to the control of relatively large loads. responsive to controlling iorces of minute magnitudemincethe force acting on. the pin 33. is primarily maintained by the unstable latchbut the small biasing force due to the inclination of the suriaces will tend to release the latch unless secured by additional means. The secondary latch constitutes the additional means for securing, but since the biasing force is of extremely small magnitude, the friction acting between the latching surfaces of the secondary latch will be; so small as: topresent no substantial resistance to actuation of the mechanism by the diaphragm 46. Thus, the relativelysmall forces: exerted by the diaphragm are entirely effective to release the heavy load exerted by the valve spring '26, with the result that the structure may be arranged to positively respond to the small differencesin pressure incident to the submerging of the nozzle. tip beneath the surface. of the liquid.

Further, the entire latching structure is simple and compact, so that it maybe positioned within the angle A in Fig, l of. the drawing, so as to add to the streamlined appearance of the device.

While I have shown and described a preferred embodiment of the present-inventioml am aware that. it is subject to numerous modifications and variations: Without departing from the invention spirit and I therefore wish to be limited only by the.- scope of the appended claims.

Having thus described my invention, I claim: 1..A,1atching; device including; an anchor ole.- ment and a supporting pivot, said, anchor element and supporting pivot; being relatively shil table with respect, to each other, guidexmeans: to establish apredetermined path of movement for said supporting pivot, and a connecting link extending between: thev anchor element and the supporting pivot; a. cam surface on the anchor element, a cam surface on. the connecting link, the arrangement. and; construction being such that, the cam surfacesof. said anchor element and said connectingy link. contact each other and. provide an unstable-latch between. the anchor element and the connecting; link, the said cam surfaces being angularly inclined with respect to the link so that forces. acting to separate the supporting pivot. and anchor will bias the latch toward released position a secondary latching device associated with the connecting link and arranged to maintain the cam surfaces of the link and anchor in contact and to prevent movement of the connecting link with respect to the anchor element, a latch actuator adapted to exert force against the connecting link in a lateral direction to cause the cam surfaces of the link and anchor to move out of engagement, and means to concurrently release the secondary latch and operate the toggle actuator to actively urge the link to disengaged positlon.

2. A latching device including an anchor element and a supporting pivot, said anchor element and supporting pivot being relatively shiftable with respect to each other, and a connecting link extending between the anchor element and the supporting pivot; a cam surface on the anchor element, a cam surface on the connecting link, the arrangement and construction being such that the cam surfaces of said anchor element and said connecting link contact each other and provide an unstable latch between the anchor element and the connecting link, the said cam surfaces being angularly inclined with respect to the link so that forces acting to separate the supporting pivot and anchor Will bias the latch toward released position, but so the bias will be insufficient to overcome the friction between the cam surfaces, a secondary latching device associated with the connecting link and arranged to maintain the cam surfaces of the link and anchor in contact and to prevent movement of the connecting link with respect to the anchor element, a latch actuator adapted to exert force against the connecting link in a lateral direction to cause the cam surfaces of the link and anchor to move out of engagement, and means to concurrently release the aforementioned secondary latch and operate the toggle actuator to actively urge the link to disengaged position.

3. A latching device including an anchor element and a supporting pivot, said anchor element and supporting pivot being relatively shiftable with respect to each other, and a connecting link extending between the anchor element and the supportin pivot; a cam surface on the anchor element, a cam surface on the connecting link, the arrangement and construction being such that the cam surfaces of said anchor element and said connecting link contact each other and provide an unstable latch between the anchor element and the connecting link, the said cam surfaces being angularly inclined with respect to the link so that forces acting to separate the supporting pivot and anchor will bias the latch toward released position; a secondary latching de vice associated with the connecting link and arranged to maintain the cam surfaces of the link i able with respect to each other, and a'connecting link extending between the anchor element and the supporting pivot; a cam surface on the anchor element, a cam surface on the connecting link, the arrangement and construction being such that the cam surfaces of said anchor element and said connecting link contact each other and provide an unstable latch between the anchor element and the connecting link, th said cam surfaces being angularly inclined with respect to the link so that forces acting to separate the supporting pivot and anchor will bias the latch toward released position; a secondary latching device associated with the connecting link and arranged to maintain the cam surfaces of the link and anchor in contact and to prevent movement of the connecting link with respect to the anchor element, a latch actuator adapted to exert force against the connecting link in a lateral direction to cause the cam surfaces of the link and anchor to move out of engagement, and means to concurrently release the secondary latch and operate the toggle actuator to actively urge the link to disengaged position, said means including a pivoted lever having a latch notch adapted to move in one direction to release the latch and an actuating arm adapted to move in a direction normal to the movement of the latch notch to urge the link toward released position.

5. A latching device including an anchor ele ment and a supporting pivot, said anchor element and supporting pivot being relatively shiftable with respect to each other, and a connecting link extending between the anchor element and the supporting pivot and adapted for arcuate movement relative to the supporting pivot whereby the connecting link will be guided in an are havin the axis of the pivot as its center; a cam surface on the anchor element, a cam surface on the connecting link, the arrangement and construction being such that the cam surfaces of said anchor element and said connecting link contact each other and provide an unstable latch between the anchor element and the connecting line, the said cam surfaces being angularly inclined with respect to the link so that forces acting to separate the supporting pivot and anchor will bias the latch toward released position, but so the bias will be insufficient to overcom the friction between the cam surfaces and the supporting pivot will be restrained against shifting movement with respect to the anchor element; a secondary latching device associated with the connecting link and arranged to maintain the cam surfaces of the link and anchor in contact and to prevent movement of the connecting link with respect to the anchor element, a latch actuator adapted to exert force against the connecting link in a lateral direction to cause the cam surfaces of the link and anchor to move out of engagement, and means to concurrently release the secondary latch and operate the toggle actuator to actively urge the link to disengaged position, said means including a pivoted lever having a latch notch adapted to move in one direction to release the latch and an actuating arm adapted to move in a direction normal to the movement of the latch notch to urge the link toward released position.

L. F. HAMMAND.

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