US1154570A - Pneumatic-despatch-tube apparatus. - Google Patents

Description

C. P. HIDDEN.

PNEUMATIC DESPATCH TUBE APPARATUS.

7 APPLICATION FILED NOV. 23. 1912. 1,154,570. PatentedSept. 21, 1915.

2 SHEETS-SHEET 1.

WITNESSES:

MW INVENTOR. M @213 Z r/J/WAMW COLUMBIA PLANOORAPH C0,, WASHINGTON, D. c.

c. P. HIDDEN.

PNEUMATIC DESPATCH TUBE APPARATUS.

APPLICATION FILED NOV. 23. 1912.

Patented Sept. 21, 1915.

2 SHEETS-SHEET Z.

INVENTOR.

COLUMBIA PLANOORAPH C0,, WASHINGTON. D. c.

ticularly set forth in the r srars Parisian @FFTQE.

CHARLES P. HIDDEN, OF WINCHESTER, MASSACHUSETTS, ASSIGNOB TO THE LAIVISON COMPANY, 035 BOSTON, MASSACHUSETTS, A CGRPOBATION OF NEN JERSEY.

PNEUMATIC-DESPATGH-TUBE APP ARATUS.

Specification of Letters Patent.

Patented se t. 21, 1915-.

Application filed Hot/ember 23, 1912. Serial No. 733,078.

and Commonwealth of Massachusetts, have I invented certain new and useful Improvements in Pneumatie-Despatch-Tube Apparatus, of'which the following is a specification. I

This invention relates to pneumatic despat'ch tube apparatus and has for one of its objects the provision of improved timing means in despatch systems operating at pressures above atmospheric- Timing mechanisms such as those described by G. H. Woodman in his Patent No. 649,094, dated May S, 1900, have been found to be of great value in practice and efiect a material saving of power in operating system of the type in question. The more accurately the timing mechanism can be adjusted to meet the conditions encountered in practice, the less the margin of time, over that actually consumed in transmitting a carrier throughthe system a determined distance, need to be allowedto assure the practically invariable delivery of the carrier; and the less this margin, the less the waste of power consumed in driving air uselessly through the transmission tube.

. In compression systems the pressure used may in some instances berelatively high and it would hence be desirable if a limiting pressure could be provided where air. for ,eX- ample, must seep through restricted or filamentary conduits or passages in order to provide a working period of proper duration. The provision of such a limiting pressure is contemplated in the herein described invention and tends to render the time element mechanism more equable in its action, regardless of the pressure used in the system, and also tends toreduce the tendency for the minute venting perforations or passages therein to become clogged by dustentrained in the air currents traversing the same.

These and other objects of my invention will be hereinafter referredto and the novel elements and combination of elements where by they may be attained will be more parclaims appended hereto.

In the accompanying drawings. which form a part hereof and in which like reference characters designate like parts throughout the several views, Thave exemplified two preferred constructions; but I am aware that various modifications and changes may be made herein without departing from the spirit of my invention, and I hence desire to be limited only by the scope of said claims. I

Referring to the drawings: Figure 1 is a vertical transverse median section of a terminal equipped with my improved timing mechanism. Fi 2 is a similar section of a modification. Fig. 3 is a detail of a combination permeable barrier and valve used in said modification.

The end of a transmission tube 1, constituting a part. of the despatch'systcm, has been shown in both forms of the device provided with a terminal 2; the tube'l. being inserted into the neck of the terminal and fixedly secured therein in a well known manner; the joint of course preferably being air tight. The terminal casing is ex tended laterally to afford a passage 4: through. which compressed air may be elelivered to a cavity 5 surrounding the eX- .tremityof the tube 1; the latter preferably being perforated at intervals therearound, as at 6. The source'of compressed air may be a pipe 7, screwed into an extension 8 of the terminal casing. said extension being recessed as at 9, toprovide a valve chamber in which is disposed a valve 10. The latter is adapted to seat against the lip 11 of an opening 12 which connects the chamber 9 with the passage l-previously referred to. The valve 10 may be of. any suitable construction and is mounted upon. a stem 13, the upper extremity of which projects through the wall of the terminal and is connectedby means of a pin 14 with a short lever 15. A coiled spring 16 normally urges valve 10 toward its closed position. The terminal. is provided with a suitable orifice 17 through which carriers may be inserted into the tube 1, said orificebeing adapted to be closed by a normally open clapper valve 18. This valve,it should suffice to say, is of a well'lmown construction in common use in this art and is pivotally mounted upon a shaft 19; the pivoting ears 20 of the backing plateZl of said valve further having a pin 22 extending transversely therethrough upon which is pi'votally mounted a lever 23. The forward extremity of this lever is provided with a handle 24 and the rear extremity thereof is provided with a hook 25 which is adapted for engagement with the forward end of the lever 15. The latter is mounted upon a pin 26 which extends through lugs 27, said lugs projecting upwardly from the surface of the terminal casing adjacent the stem 13. A coiled spring 7 dicated by dotted lines in said figure.

28 in a recess 29 in the lever 23 provides for a proper and effective closure of the clapper valve when said lever 23 is in the position in whichit is shown in full lines in Fig. 1. A spiraled spring 29 disposed around the shaft 19 and suitably connected as at 30 to one of the ears 20 exerts a tendency to swing the clapper valve into its open position, in-

The action of the spring 29 however, is resisted by a latch 31 pivotally mounted as at 32 between ears 33 of an auxiliary casing 34; said latch operatively engaging a hook 35 which depends from the under side of the lever 23. Latch 31 is held normally in its operative or latching position by means of a light spring 36 and thelower extremity of this latch lever may be provided, if desired, with a set-screw 37, the function of which will be hereinafter referred to.

The supplementary casing is' preferablypiston 42 which correspondingly rides in a cylindrical recess 43 within a cap 44. This cap is further preferably adapted to be readily separated from the supplementary casing 34 upon the outer face of which it is mounted, so as to afford access to the respective pistons.

A valve 45 of somewhat peculiar construction is pivotally connected as at 46 to the outer end of the cap 44, suitable means, such for example as a leather washer 47 (sethe latter in a well known manner.

one and indeed in practice it is desirable to I reduce it, when the pistons are so disposed, to the smallest dimensions possible. A needle valve 50, or the like, provides means for closing the aperture 49 the desired amount; this valve being mounted in an apertured cup 51 which secured upon the outer side of the valve 45. lhis cup is also preferably made readily separable from said valve so as to permit of the perforation 49 being cleaned out to free it from the accumulation of dust which is deposited therein by the currents of air which traverse the same; and also to permit of cleaning the needle point of the valve 50. This latter may, if desired, be provided with a lock nut 52 so that when it hasonce been set to determine the rate of flow of air through the perforation 49 it will not be disturbed when the cup 49 is removed for cleaning purposes.

The pistons 39 and 42 may be provided with leather cups 39 and 42 in a well. known manner to insure air tight closures therearound; and the backing plate 53 of the cupor disk 39 is preferably provided with a boss or extension 54 to permit either said extension or, as in the present case, the riveted end 55 of the piston stem 41 to engage the head of the set-screw 37. Means are provided for admitting pressure iiuid to the chamber 40 and such means, in the present instance, consists of a small tube or pipe 56 which connects a preferably enlarged portion of the chamber 40 with the passage 4. I also prefer, in some cases, to

provide means for throttling the flow of pressure fluid from the passage 4 into the chamber 5; any suitable device being employed for this purpose. In the present instance a throttle valve 57 has been utilized, the function of which will be hereinafter referred to.

The operation of the device is as follows:

After a carrier has been inserted into the terminal opening 17, the valve 18 is closed by means of the handle 24 and is automatically latched by the latching part 31. The last portion of-the movement of the valve lever 23 brings the hook 25 at the rear extremity thereof into engagement with the lever15 which rotates about its axis and thereby effects the opening of the normally closed valve 10. It may here be noted that the extremities of the pin 14 which connect the lever 15 with the valve stem 13 preferably ride in slots 58 in the bifurcated end of this valve stem. The valve 10 normally does not open until the clapper valve 18 has been seated so that there is practically no tendency to waste the pressure fluid; the latter passing through the opening 12, passage 4 and chamber 5, into the upper end of the transmission tube'and propelling the carrier through While the compressed. air is passing into the chamber some of it will also pass through the tube 56 to the chamber 40. Herev it will, of

course, exert pressure against the opposed walls of the two pistons but since the piston 39 is materially larger than the other, the piston rod or stem 41 will move toward the left as viewed in Fig. 1; its movement being impeded by the creation of a vacuum or partial vacuum in front of the piston 42 but to the left thereof as viewed in- Fig. 1. Air, however, slowly seeps in through the throttled aperture 49 and hence permits the pistons to continue their movement toward the left; the speed of this movement being governed by the position of the valve 50. The

advance of the pistons toward the left finally brings the head 55 of the piston stem into engagement with the head of the set-screw 37 and immediately thereafter trips the latch 31 releasing the lever 23 and permitting the latter, together with the clapper valve attached thereto, to swing open under the influence of the spring 29. This tripping of the latch is so timed as to. insure the delivery of the carrier to the terminal at the other end of r the line and the set-screw 37 permits of the regulation of this period to an extreme nicety. As the clapper valve 18 is thus swung open, the lever 15 is substantially simultaneously released and the spring 16 closes the valve 10 preventing a further efliux of pressure fluid through the passage The latter being now in communication with the atmosnormal positions and this action is permitted by reason of the pivotal mounting of the valve which swings upwardly and permits the confined air to freely escape around said valve; the latter thereafter being immediately returned to its closed position. When the transmission line is of'considerable length there is practically no necessity for providing a throttle 5'7 since .suflicient pressure in the chamber 40 to actuate the pistons in the manner above'described will be practically invariably developed under such conditions. here, however, the transmission line is very short, it is advisable to provide some means for insuring the development of adequatepressure in said chamber 40 and the throttle 57 conveniently provides such means since it prevents the too free flow of air into the chamber 5 from the passage 4 and insures an adequate flow of air from said passage 4 to the chamber 40. By reason of the fact that the pressure of air, upon the pervious barrier or valve 45 can never exceed that of the atmosphere, the flow of air through the perforation 49 can be regulated or determined to an extreme nicety and this despite the fact that the operating pressure in the line' may be relatively high. Furthermore, owing to this limited pressure upon the barrier in question the speed of the current of air flowing through the perforations therein can never exceed a determined amount which not only permits of a more accurate regulation of the timing mechanism but further tends to reduce the tendency experienced in practice for the dust entrained in'the air to gradually clog or choke up the perforation. If desired, also, a pledget 59 of absorbent cotton, gauze, vor the like, may be disposed within the-cavity in the cup 49 which will, of course, tend to filter the air and thereby reduce this clogging action.

In the form of device shown in Fig. 2 the construction is practically identical in all respects with that employed in the form of device shown in Fig. 1 except thatin this case the supplementary casing 34 has but a single piston 60. The piston rod 61 of the latter rides in the bearing 62 which forms a part of the front wall of the cylinder 68 within which the piston travels. Air is admitted to the space between this'wall and the piston by means of a tube 56, as in the preceding case. The outer extremity, of the piston rod, in the present instance, carries a dished disk 64 around which isdisposed a collapsible or folding wall 65 not dissimilar to the wall of a Chinese lantern.

This wall may be made of treated linen or some other suitable'tough material which naturally is, or which has been treated to be, substantially impervious to air. When in its outermost position, the outer face of the disk 64 is received into an aperture in an annulus 66 to the outer side of which is hinged a valve 67 of porous material through which air may pass or seep slowly. In other words, this valve may be such a permeable barrier as is described by the said George H. Woodman inhis patent above referred to. I prefer, however, to provide means for regulating the flow of air through this barrier and one very simple form of such means consists in merely lightly gumming a sheet 68 of non-porous paper to the outer face of this flap or valve 67. If desired, this sheet may be slit as at 69 (see Fig. 3) and any desired portion thereof may be torn away as at 70, without disturbing the remainder, to expose the surface of the perwvious barrier 67. One advantage. of this construction resides in'the fact that as the pores or minute apertures in this material become clogged up it is merely necessary to l-l-l remove a further portion of the covering sheet 68 so as to regain the desired flow of air into the space within the folding walls 65. The annulus 66 may be retained in place by means of an apertured cap 71 and screws 2, or the like, said cap, of course being readily removable to permit of access to the valve 67. A light spring 73 may be secured to the inner side of the cap 71; the free end of said spring bearing against the outer side of the valve to insure a prompt closure thereof after it has been swung outwardly to permit of the air in front of the disk 64: being expelled. The rear flange 7a of this disk is adapted for engagement with the point of a set screw 75, said screw being carried by an arm of the latch 76, substantially the same as in the preceding case. This form of the device operates in much the same fashion as does that previously described the only material differences being that the outer or smaller piston in the present case has been replaced by the structure provided with folding walls and that the previous barrier in this instance is made of porous material or of material. having pores made therein and further, that the means for regulating the flow of air through the said barrier is of a different type from that previously discussed. The closure of the valve 18 effects an opening of the valve 10 whereupon air rushes through the tube into the space in front of the piston impelling the latter rearwardly and thereby creating a partial vacuum in the space betweenthe flap or valve 67 and the disk 64:; the slow seepage of air through the pores of the valve 67 pcrmitting'the piston to continue its travel to the left, as viewed in Fig. 2, at a relatively slow rate of speed until the flange 74 unlatches the lever 23 byits engagement with the screw 75. Thereafter the valve 10 is closed as previously described and the air confined between the piston and the front wall of its cylinder is driven out again through the tube 56 by reason of the action of the spring 76' which bears against saidwall and'against the disk 64 and which performs substantially the same function as does the spring 58 previously referred to. The outward movementof the disk 6% expels the air which had previously seeped in through the pervious barrier by forcibly raising said barrier or valve from its seat; the latter thereupon being re-seated by a spring 78. Indeed, in many cases this latter element is scarcely necessary since the mere tendency to form a' vacuum 7 between the valve 67 and the disk 64 will cause said valve to seat itself firmly.

In general, the provision of means for opposing the movementof a timing element in a mechanism of the character above described, by fluid pressure of a sign opposite to that which tends to move said ele ment, is believed to be broadly new; and the advantages'of sucha provision have been above pointed out at length.

Having thus described my invention, what I claim is: i

1. Pneumatic transmission apparatus comprising a'member having a bias for a determined position with respect to other parts of said apparatus, and time element mechanism for controlling the return of said memher to said position after displacement therefrom, said mechanism including an instrumentality, displaceable in a given direction by fluid pressure, means to supply said fluid pressure, and cooperating vacuum forming ineans'having a vacuum forming chamber therein provided with auxiliary means to admit pressure fluid at a determinedrate to said chamber and co-acting with saidinstrumentality when the latter is moved in a given direction, for retarding said movement to time the return of said member, said mechanism also including means to hold said member against return to said position thereof until said instrumentality has reached a determined point in its path of travel in said given direction.

2. Pneumatic transmission apparatus comprising a valve having a bias for a determine dposition with respect to other parts of said apparatus, and time element mechanism.

for controlling the return of said valve to said position after displacement therefrom,

said mechanism including an instrumentality displacement in a given direction by fluid pressure means to supply said fluid pressure, and cooperative vacuum forming means havinga vacuum forming chamber therein provided with auxiliary means to admit pressure fluid at a determined rate to said chamber and co-acting with said instrumentality, when the latter is moved in 'a given direction, for retarding such movement to time the return of said valve, said mechanism also including means to hold said valve against return to said position thereof until said instrumentality has reached a determined'point in its path of travel in said given direction.

3. A; transmission system comprising a source of compressed air, a member having a bias for a determined position, and time element'mechanism for controlling the return of saidmember to said position after displacement therefrom, said mechanism including an instrumentalitv displaceable in a given direction by compressed air from said source of the same and cooperating vacuum forming means co-acting with said instrunientality when the latter is moved in a given direction, for retarding such movement to properly time the same. 7

4.13. transmission system comprising a source of compressed air, a valve having a master a determined position, and time element mechanism for controlling the return of said member to said position after displacement therefrom, said mechanism including a latch and an instrumentality for actuating said latch, said instrumentality being adapted for displacement by compressed air from said source of the same, and cooperating vacuum forming means co-acting with said instrumentality when the latter is moved in a given directiomfor retarding such movement to properly time the same.

5. In pneumatic despatch tube apparatus, a transmission tube and means for establishing a propulsive fiuid pressure in said tube, in combination with a cooperating time element mechanism for said apparatus, said mechanism comprising a part movable by said fluid pressure and means for retarding, by an opposing fluid pressure of opposite sign, a movement of said part, and means controlled by said mechanism and co-acting with a part of said fluid pressure establishing means to disestablish said propulsive fluid pressure after said movable part has traveled a determined distancewhil'e subjected to the action of said retarding means.

6. A transmission system comprising a holding said valve in a determined position,

and time element means for actuating said holding means, said time element means including an instrumentality, movable by compressed air from said source or" the same, and cooperating vacuum forming means co-acting with said instrumentality, when the latter is moved by said compressed air insaid given direction, for impeding such movement.

In testimony whereof I have afiiXed my signature, in the presence of two witnesses.

CHARLES P. HIDDE Witnesses:

B. J. SMITH, Isaac KnAFsUR.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G,

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