US3448833A - High-torque pneumatic-type rotary timer - Google Patents

Description

June 10, 1969 w. T. WEISMANN 3,448,833

HIGH-TORQUE PNEUMATIC-TYPE ROTARY TIMER Filed Dec. 12, 1967 Sheet 'of 2 INVENTOR. WALTER T WEISMANN BY Flg. 4 34 WW TOR NEYS June 10, 1969 w. T. WEISMANN 3,448,833

HIGH-TORQUE PNEUMATIC-TYPE ROTARY TIMER Filed Dec. 12, 1967 Sheet 2 of 2 j 2 ag F|g.6

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7 WALTER T WEISMANN BYH m 3411 3| ATTORNEYS United States Patent 3,448,833 HIGH-TORQUE PNEUMATIC-TYPE ROTARY TIMER Walter T. Weismann, Hackettstown, N.J., assignor to the United States of America as represented by the Secretary of the Army Filed Dec. 12, 1967, Ser. No. 690,029 Int. Cl. F16d 57/00 US. Cl. 188-91 2 Claims ABSTRACT OF THE DISCLOSURE A rotary timer wherein pneumatic escapement at high torque levels is provided. Two coaxial diametrically-opposed air cylinders are mounted on complementary crank case housing blocks which jointly provide a sealed crank case chamber between the cylinders. A pair of opposed pistons, one in each cylinder, are connected with a central common crank shaft, each by a two-part connecting rod, the piston ends of which are coaxial with the pistons and the crank shaft ends of which are offset. An air manifold connects the outer ends of the cylinders to permit air flow from one to the other as a closed system, in response to piston movement 'as the crank shaft is driven by a torque-producing device or rotary power source to be time controlled. A rotary valve in the manifold connection may be set full open or partially closed to any desired degree to set the timing rate of the timer. This varies the restriction or resistance to air flow through the manifold and thus the rate at which the timing crank shaft may be rotated with applied torque from the controlled device or power source.

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

The present invention relates to mechanical escapement rotary timers, and has for an object to provide a more rugged timer of that type for controlling angular velocity over a relatively-wide speed range at relatively-high torque levels. It has been found that by resorting to pnematic escapement control in timing devices numerousadvantages may be gained over the basic mechanical escapement as found in watches, clocks and conventional timing devices. Greater immunity from shock, vibration, spin and setback forces can be attained. With a pneumatic escapement, a greater amount of mechanical energy can be absorbed without the use of large gear trains. The conventional method for controlling the angular velocity of the timing movement, as in a watch, by a hair-spring adjustment, provides a limited speed or variation range and the structural elements involved are relatively fragile.

A pneumatic type escapement timer in accodance with the invention, however, is adapted for use where:

(a) Angular velocity or rotational speed must be controlled at relatively high torque levels,

(b) A relatively wide range of speed adjustment is required', and

(c) A conventional mechanical escapement is not rugged enough to meet environmental operating conditions.

In accordance with a present preferred form of the invention, a high-torque pneumatic-type rotary timer is provided in a closed system that can be hermetically sealed so that no outside 'air or gaseous fluid is required for the continuous operation thereof. A pair of doubleacting pistons and cylnders are arranged in coaxial diametrically-opposite relation to each other about a central crank shaft to which the pistons are connected. The crank "Ice shaft extends outwardly at one end from a divided blocktype crank case of relatively large mass for connection with any torque-producing power source or device which requires high-torque timing control.

The piston connecting rods are of a two-piece welded construction more readily to provide an off-set driving connection with the crank shaft. When driving torque is applied to the crank shaft the pistons are moved in unison by the shaft rotation on alternate compression and intake strokes. A manifold or conduit connection is provided between the outer end of the cylnders to permit a flow therebetween to equalize the pressure between the cylinders as the pistons move on the compression or exhaust stroke in the one and the decompression or intake stroke in the other. The inner ends of the cylinders are more closely and substantially-directly connected 'by the sealed crank case which thus provides for air flow and pressure equalization therein as the pistons move.

A rotary valve in the manifold or conduit connection acts as a variable impedance element for restricting the air flow from one cylinder to the other to 'any desired degree and thereby loading the crank shaft to provide timing control in a corresponding degree. A heavy driving torque can thus be controlled and the timed release of the driving force can be set over a relatively wide speed range.

The invention will, however, be further understood from the following description of a present preferred embodiment thereof when considered with reference to the accompanying drawings.

In the drawings,

FIG. 1 is frontal View, in perspective, of a high-torque pneumatic-type rotary timer embodying the invention,

FIGS. 2 and 3 are similar views of two related and complementary parts of the timer of FIG. 1, showing further details of construction in accordance with the invention,

FIG. 4 is a further view, in perspective, of an assembly group of elements of the timer of FIG. 1, also showing additional details thereof in accordance with the invention,

FIG. 5 is an enlarged cross-sectional view of the timer as in FIG. 1, taken on the section line 5--5 thereof, to show the construction and operative relation of the in-- terior elements in accordance with the invention,

FIG. 6 is a fragmentary cross-sectional view, of a portion of the timer as in FIG. 5, showing a change in the position of a control element thereof for operation in accordance with the invention, and

FIG. 7 is a top view of the timer as in FIG. 1 in operative relation to a power source for timing control thereof in accordance with the invention.

Referring to the drawings, wherein like reference nuerals are used to designate like elements throughout the various figures, and referring particularly to FIGS. 1-3 inclusive, a central relatively-massive crank case housing 12 carries two diametrically opposed cylinders 10 and 11 which are mounted on complementary crank- case housing blocks 12A and 12B respectively. The latter are of rectangular construction with a central grooved recess 14 in each face thereof as shown in FIGS. 2 and 3, which unite to form a centrally-located crank-case chamber 15 between them within the housing 12 as shown in FIG. 5. to which attention is now directed along with FIGS. 1-3.

'Iwo opposed pistons 16 and 17 in the cylinders 10 and 11, respectively, are connected with a central rotary transversely-extending crank shaft 18 by coaxial connecting rods 19 and connecting rod extensions 20 therefor on opposite sides of the common piston and cylinder axis as indicated. The connecting rods 19 are connected with the respective pistons by wrist pins indicated at 21 and are joined to the extensions 20 by any suitable means 3 such as elongated joints or welds 22 as shown in FIG. 5.

The crank shaft is provided with an intermediate crank pin section comprising two-spaced crank arms 24 and a connecting crank pin 23, between inner and outer shaft sections, which are journaled in end bearings or hearing plates 26 and 27, respectively. The latter are mounted on opposite faces of the assembled crank case housing. A circular-spacing block or washer for the connectingrod ends of the extensions 20 is provided on the crank pin 23. The bearing plates serve to hold the housing blocks in tight closed relation and may be attached thereto by any suitable means, such as four mounting screws 28 (FIG. 1). The forward section of the crank shaft extends outwardly of the bearing plate 27 and the crank case housing 12, as indicated at 18A, for connection with any torque-producing device or rotary power source to be time controlled, as will hereinafter be described.

It will be seen that the crank case chamber .15 is completely closed or sealed between the housing blocks 12A and 12B and covered by the bearing plates 26 and 27. The crank case may thus be partly filled with lubricant and completely sealed. The air therein is subject to free flow between the inner cylinder ends to equalize the pressure changes therein caused by the reciprocating piston movement.

At the outer ends of the cylinders the pressure changes caused by the piston movement are equalized through external connecting and timing control means of unitary construction. This is further shown in FIG. 4 as it appears before mounting on the cylinder and crank case housing, and in FIGS. 6 and 7 to which attention is also directed. It comprises a tubular air manifold 30* having two conduit arms 31 and 32 with a central valve casing 29 therebetween. The valve casing is mounted on and may be integral with, the rear bearing plate 26 to extend axially and rearwardly of the crank case housing 12, also as shown in FIGS. 1 and 5.

The free ends of the manifold or conduit arms 31 and 32 are terminated in cylinder heads 33 and 34 respectively for the cylinders 10 and 11 and are in communication with the outer ends thereof through a slotted opening 35 on the inner face of each cylinder head. The cylinder heads are attached to the cylinders by any suitable means such as screws 36 as indicated in FIG. 1. These and other screws, such as 28, are omitted in FIG. 5 to aid in clarifying the showing of other structural elements.

The valve casing 29 is provided with a rotary valve element 39 between the ends of the conduit arms 31 and 32 therein as shown in FIGS. 5 and 6. The valve element is provided with a transverse opening 40 which can be turned into the open position in alignment with the conduit arms, as in FIG. 6, to permit full fluid flow therethrough or turned, as in FIG. 5, to partially close and restrict the fluid flow therethrough as a load on the piston elements 10 and 11. A manual control knob 41 is connected with the valve element 39, as outlined in FIGS. 5 and 6 and shown in FIGS. 1, 4 and 7, to set the valve open to various degrees for timing control. Thus the control knob may be graduated or provided with a graduated scale 42 and a fixed indicator or pointer means 43- therefor, FIG. 7, to aid in setting the valve as above. In FIGS. 1 and 7, the scale 42 is shown with the knob 41 adjusted for the full open position of the valve, as in FIG. 6.

" As shown in FIG. 7, the timing control shaft 18, that is, the outer end 18A, may be connected to apply timing control to a rotary shaft, such as a shaft 44, which operates to apply a high degree of torque. It may be a driven electric generator shaft in connection with a power source or it may, as here, be the shaft of a high-torque power source 45, the opposite end of which provides a driving torque for any useful purpose at a fixed speed. In order to operate the timing control means at a relatively low speed in connection with a higher-speed hightorque device at 45, the shafts 18A and 44 may be connected by suitable gearing, such as a small pinion driving gear 46 on the shaft 44 and a larger driven gear 47 on the shaft 18A.

What is claimed is:

1. A pneumatic high-torque variable-speed rotary timer, adapted for immunity from shock, vibration, spin and setback forces, comprising in combination,

a pair of complementary rectangular crank-case housing blocks of relatively-large mass with a central grooved recess in each face thereof jointly providing a crank case with an inner crank-case chamber,

a pair of diametrically-opposed cylinders mounted on said crank case one in connection with each of said housing blocks and communicating with said chamber at their inner ends,

a central crank shaft extending transversely through said chamber,

opposed coaxially-aligned pistons one in each of said cylinders connected with said crank shaft each by a two-part connecting rod the piston end of which is coaxial with the piston and the crank-shaft end of which is offset therefrom,

fluid-conduit type manifold means connecting the outer ends of the cylinders to permit fluid flow from one to the other in response to piston movement,

rotary valve means for said manifold means adapted to be set full-open or partially-closed to any desired degree and connected therein to vary the restriction and resistance to fluid flow therethrough for applying high-torque timing control to devices connected with said crank shaft, said rotary valve means including a valve casing providing a gear bearing for the crank shaft and closure means for the rear of the crank case,

whereby the angular velocity of the crank shaft over a relatively wide speed range can be controlled thereby at relatively high-torque levels, and

manual adjustment means including a graduated dial for setting said valve means to control the timing rate of said timer.

2. A pneumatic high-torque variable-speed rotary timer as defined in claim .1, wherein the cylinders are closed at the outer ends by detachable cylinder heads carried by the ends of the manifold means and forming a unitary part thereof and the manifold means further includes two thin-walled pipe-like conduit arms connected one between said valve casing and each of said cylinder heads.

References Cited UNITED STATES PATENTS 1,630,711 5/1927 McCleary l8'891 1,907,017 5/1933- Turman l889l X 3,026,974 3/1962 Gouker l8891 GEORGE E. A. HALVOSA, Primary Examiner.

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