US2714440A - Devices for ejecting flat articles - Google Patents

Description

A. J. FQRTY ET AL 2,7%,440

3 Sheets-Sheet l Aug. 2, w55

DEVICES FOR EJECTING FLAT ARTICLES Filed July 24, 1951 A. J. FGRTY 15T AL DEVICES FOR EJECTING FLAT ARTICLES Aug. 2, w55

3 Sheets-Sheet 2 Filed July 24, 1951 0 00 5 \T 5 4 3 5 p. l Hun ||||Hu |I|rn l 5 6 6 J 9. 3 m F /\n 4 m2 WFM m @fh frw/VA 5 Sheets-Sheet 5 A. J. FORTY ET AL DEVICES FOR EJECTING FLAT ARTICLES Aug. 2, 1955 Filed July 24, 1951 United States Patent Oice 2,714,440 Patented Aug. 2, 1955 DEVICES Fon EJECTING FLAT ARTICLES Albert Ilohn Forty and Arthur. Frederick Whiilock,

Chesham, England, assignors to Hall Telephone Accessories Limited, London, England Application July 24, 1951, Serial No. 238,224 Claims. (Cl. 198--34) This invention relates to devices for ejecting flat articles such as postal letters or thin packets and is more particularly, although not exclusively, concerned with devices for ejecting postal letters from a stationary position on to a moving conveyor belt. Such devices find application in mechanised processes of sorting letters in which an operator is able to control the placing of letters on to a conveyor belt on which the letters travel until they are diverted into their respective destination boxes.

The objects of the invention `include the provision of a device which is of simple, robust construction, is economical in power consumption and which is capable of operating over long periods with a minimum of attention. Further objects of the invention are to provide a device which Will eject letters without delay at desired `instants of time and will impart a substantially uniform velocity to all letters irrespective of difference in their size, thickness or weight.

According to the present invention, a device for ejecting articles from a position of rest comprises an article support, a portion at least of which in the operation of the device moves in the direction in which the article is `to be ejected, a stop member which normally restrains `the article from being moved by the support, means for removing at a desired instant, the restraint imposed by the stop member on the article and further means for continuing or accelerating the movement imparted to `the article by the support when said `restraint is removed.

ln a particular form of device embodying the invention the `article support consists of a driven endless belt and the means for continuing or accelerating the movement `imparted thereby to the article consist of co-operating `resilient rollers one at least of which is driven and which receive the article `between them from the belt and then eject it.

The stop member, in a device according to the invention, may comprise an `electro-magnetically operated barrier or gate which is normally retained in the stop position;e. g. by spring `means and is removed therefrom on energisation of electromagnetic means.

In another form of the device according to the invention, the stop member may comprise a mechanically operated barrier or gate which is normally retained in the stop position, e. g. by spring means, and is removed therefrom by engagement with a mechanically driven travelling member which may be moved into operative or` inoperative position relatively to the stop member under electro-magnetic control.

The stop member may be made to withdraw at any desired speed from the stop position and letter retained thereby, but it is at present considered to be of `advantage for the `stop member to be withdrawn from the stop .posi tion and letter in such a manner that it travels with and controlsthe movement of the released letter until the letter has attained the speed of the moving article support upon which `it is carried.

In ,order that ,the invention may be clearly understood, forms of devices constructed to operate in accordance therewith will hereinafter be more particularly described by way of example and with reference to the accompanying drawings in which:

Fig. 1 is aside elevational view of one constructional embodiment of the invention,

Fig. 2 is a plan of Fig. 1,

Fig. 3 is an end elevational View looking in the direction of the arrow A (Fig. 1),

Fig. 4 is an end elevational view looking in the opposite direction from Fig. 3 and as seen in section on the line B-B in Fig. 1.

Fig. 5 is a line perspective view of the further side of the device, showing the electro-magnetic gate-operating mechanism thereof,

Fig. 6 is a diagrammatic plan view showing the operative disposition of the device in relation to a fast moving main conveyor belt for letters,

Fig. 7 is a side elevational View of an alternative constructional embodiment of the invention,

Fig. 8 is a plan of Fig. 7,

Fig. 9 is an end elevational view looking in the direction of the arrow C in Fig. 7, and

Fig. l0 is an enlarged plan `view of certain of the details shown in Fig. 9.

The device shown in Figs. 1 to 5 comprises a frame composed of two horizontal bars 1, 1a of angle iron or strong light metal alloy, with their vertical faces spaced apart to accommodate an endless conveyor belt 2 supported on a follower roller 3 and driving roller 4 mounted between the bars 1, 1a near the opposite ends thereof. Guide plates 5, of approximately the same dimensions as the average postal letter L, are supported vertically, one from each of the opposed vertical faces of the bars 1, 1a to form, with the conveyor belt 2 as a base, a vertical boX-like container or stall 6 with an open top and ends. The guide plates 5 are `fixed to a smaller mounting plate 7 secured to the upright .flanges of the frame bars.

The spindle 8 of the conveyor belt follower roller 3 is mounted in bearing slots 9 in the frame bars and adjustable thrust screws 1t), engaged in threaded nuts iixed to the frame bars, bear on the ends of the spindle to effect the requisite adjustment in the position of the spindle in order to tension the conveyor belt. The spindle 11 of the conveyor belt driving roller 4 is supported in xed bearings mounted in the frame bars and one end of the spindle 11 projects outwards from the frame bar 1 to carry a pinion Wheel 12 xed thereto and meshing with another pinion wheel of a gear train 13 mounted in bearings upon the horizontal flange of the frame bar 1.

The gear train 13 includes a chain sprocket wheel 14 to receive a driving chain (not shown) whereby the gear train is driven e. g, from an electric motor disposed below the device.

A pair of co-operating smooth edged soft rubber snatch rollers 15, 16 are keyed to the upper ends of vertical spindles 17, 18 which are journalled in pedestal bearings 19, 20 respectively mounted one on each of the framerbars. The spindles 17, 18 are disposed in such amanner that the soft faced edges of the snatch rollers 1S, 16 abut suiiiciently to establish driving engagement therebetween. The edges of the snatch rollers abut in the central vertical plane between the opposed vertical faces of the frame bars and guide plates. The top surfaces of the snatch rollers lie above the upper stretch or" the conveyor belt 2 at a height for example about equal to a quarter of the height of the average letter L when the letter is supported edgewise as shown. The snatch roller 15 is positively driven from the gear train 13, through a bevel wheel 21 which meshes with a bevel pinion 22 mounted on the spindle 17, and in turn serves to drive the snatch roller 16. The bearing 2l), in which the snatch roller spindle 18 is mounted, is carriedby an arm 23 which pivots about a vertical pivot upstanding from the horizontal ilange of the frame bar 1a. The bearing arm 23 is adjustably spring loaded by a spring 24 carried upon a threaded bolt 25 secured to the vertical tiange of the frame bar 1a and projecting through a slot in the bearing arm to receive the spring and threaded nut means for adjusting the spring-loading. The adjustable spring-loading means thus serve yieldingly to hold together the abutting edges of the snatch rollers and enable the pressure therebetween to be preset.

The frame bar la also carries a vertically extending solenoid 26 disposed behind the snatch roller 16 and adjacent to the discharge end of the container or stall 6. The projecting upper end of the solenoid plunger 27 has a bolt 32 passed therethrough to form a pivotal attachment for the lower horizontal limb of a double right angle bracket 2S which is pivoted by a spindle 29 to a bearing bracket 3i) fixed to one of the vertical mounting plates 7.

The axis of the spindle 29 is slightly inclined with respect to the longitudinal centre line of the device as shown in Fig. 4. Y A helical spring 31 is anchored at one end to the xed bracket 3G and at the other end to the pivot bolt 32 so that the spring 31 pulls upon the plunger Z7 normally to draw it upwards from the solenoid and to tilt the pivoted bracket 2S upwardly about its inclined pivot. On the other hand, when the solenoid is energised the plunger is drawn downwards by an inductive force greater than the force of the spring 31 and thus tilts the pivoted bracket 28 downwards.

An L-shaped member 33, which acts as the stop member or gate and will hereinafter be referred to as a gate, has its shorter ,limb bent at right angles to the face of the longer limb thereof and adjustably attached to the upper horizontal limb of the pivoted bracket 28 by means of screws 33a which pass through a slot in the shorter gate limb and engage screw threaded holes formed in the bracket limb, thus providing for adjustment of the setting of the gate. The larger limb of the L-shaped gate is made arcuate and has a flat substantially vertical letterengaging face which, upon upward tilting of the pivoted bracket 28, projects across the gap between the guide plates 5 which constitutes the open discharge end of the container or stall 6 and so prevents egress from the discharge end of the container or stall 6 of any letter placed upon the moving belt conveyor 2 of the ejecting device as shown in chain lines in Figs. 3 and 4, Alternatively, when the pivoted bracket 28 is tilted downwards, the gate 33 is withdrawn from the stop position, as shown in full lines in Figs. 3, 4 and 5.

ln the use of the device as above described, it is located adiacent to a fast moving main letter-carrying conveyor belt 34, the letter-carrying surface of which is disposed at a level slightly below that of the letter-carrying surface of the conveyor belt 2 of the device. As shown in Fig. 4, the device is located in relation to the fast moving main letter-carrying conveyor belt 34 so that the angle of discharge, i. e, the angle between the line of travel of the fast moving rnain conveyor and line of travel of the letters ejected from the device is as small as is practicably possible. It is at present considered that an angle of discharge of not more than l5 degrees is of advantage. The fast moving main conveyor beit 34 will be provided with vertical side plates along its length to maintain the letters carried thereby substantially erect.

The purpose of the device described above is to control the instant at which letters are ejected on to the fast moving conveyor and, in operation, letters are fed on edge into the container or stall 6 through the open receiving end thereof opposite to the snatch roller and by means of travelling bands (not shown) which convey the letters to the stall one by one.

Assuming that a letter L is standing in the stall awaiting ejection, and normally retained therein by the gate 33 extended across the open discharge end of the stall (as shown in Fig. l), the continuously driven conveyor belt 2 will slip beneath the lower edge of the letter supported thereon but will keep the forward vertical edge of the letter in close contact with the inner at face of the gate. The rubber snatch rollers 15, 16 are continuously rotated at a circumferential speed equal to the speed of the fast moving main conveyor belt (which may be as much as ten times that of the conveyor belt 2 of the ejecting device) so that, on energisation of the solenoid 26 and consequent removal of the gate from the path of the letter standing in the stall, the letter will be carried forward by the conveyor belt 2 towards the snatch rollers which, owing to their higher speed of rotation, will snatch the letter engated thereby and eject it sharply on to the fast moving main conveyor belt. As the horizontal velocity of the letter when snatched and ejected will. be approximately the same as that of the fast conveyor belt, no appreciable slip or repulse will take place when the letter alights on the main conveyor belt providing that the letter is moving at a properly chosen speed.

The device therefore enables each letter ejected thereby to be placed with precision on to any desired position on the main conveyor belt and a tine control of this placing can be obtained by adjusting the position of the gate relative to the snatch rollers.

in the device above described, the inclination of the pivot of the bracket 2S which carries the gate 33 is such that the gate itself moves away slightly in the direction of travel of the letter L when the bracket is tilted downwards. By this arrangement, if the gate is suddenly removed from the letter-stopping position it will withdraw without scraping the at inner face thereof across the forward edges of the letter.

On the other hand, it has been found that if the gate is suddenly withdrawn from the stop position so as to leave the stationary letter completely tree to move with the conveyor belt upon which it is resting, the period of slip between the conveyor belt and letter which occurs before the letter attains full belt speed is indeterminate between certain limits and may thus cause varying time lags in the engagement of the letter by the snatch rolls and lead to lack of precision in the placing of the letter upon the fast moving main letter-carrying conveyor belt.

t is, therefore, at present preferred to keep the gate in controlling contact with the leading edge of the letter after the latter has been released to move with the conveyor belt and for a period at least equal to the predetermined maximum time taken by the letter to attain the full speed of the conveyor belt. The gate of the above described device may be adapted to maintain control of the letter in the manner last described, by braking or otherwise slowing the tractive action of the energised solenoid and shaping and/ or angularly inclining the eccentrically pivoted gate so that in being withdrawn from the stop position it moves ahead of the moving letter for a given time for a distance which is less than the minimum distance which would have been covered in the same time by the letter if left completely free upon the conveyor belt of the ejecting device. Thus the gate remains in denite controlling contact with the moving letter until the latter reaches conveyor belt speed, whereupon the gate is drawn completely clear of the letter at a positively determined interval of time after the energisation of the solenoid to release the letter from its stall.

Another form of stop of gate intended for use in carrying the invention into effect and adapted to be embodied in a modified form of the above described ejecting device is shown in Figs. 7, 8, 9 and 10. ln this form, the gate comprises a flanged rectangular plate 35 mounted upon a vertical pivot 36, so as normally to extend as a stop across the open discharge end of the letter-containing stall 6, and yieldingly maintained in the operative position shown in the drawing by a helical tension spring 37 anchored to a fixed part of the structure of the device and secured to an arm 3S extending rigidly from the pivoted end of the gate 35. The free end of the arm 38 extends immediately above the top surface of a continuously rotating power driven disc 39 which is mounted upon a vertical spindle 4t) disposed in offset relation to the axis of pivotation of the gate 35. The disc 39 carries a finger or plunger 41 extending upwards from the top thereof so as slidingly to engage the edge of the arm 38, which extends across the circular path of travel of the finger as the latter is carried round by the rotating disc. Assuming that the disc 39 and finger 41 rotate in anticlockwise direction (as viewed in. Fig. 8) the finger 41 will move the arm 38 and gate 35 in clockwise direction about their pivot 36 and thus withdraw the gate from the path of the letter L held in the stall 6. The parts are so dis* posed that the distance between the point of contact of the nger 41 with the edge of the arm 33 and the gate pivot 36 is progressively decreased as the finger travels along its circular path to displace the arm and thus the gate is withdrawn from the forward edge of the letter at a progressively accelerated speed.

The degree of acceleration of the gate movement depends upon the ratio between the radius of the circular path of movement of the finger 41 and distance between the axis of rotation of the finger and axis of pivotation of the gate and may be varied by adjustment of the relative settings of the operative parts.

The mechanically displaced gate may thus be arranged to release the letter by initially moving ahead of the letter at a speed which accelerates at a lower rate than the minimum rate of acceleration of an unimpeded letter so that the letter remains in contact with the gate and is controlled thereby until the letter has attained full belt speed whereupon the gate which continues to accelerate is fully withdrawn from the path of the letter which then passes to the snatch rollers, whereupon the gate is returned by the spring 37 to the stop position.

Provision must be made for holding the finger 41 normally withdrawn to avoid engagement with the arm 38 until it is desired momentarily to displace the gate in order to release a letter from the stall and this may be efected by electromagnetic means. For example, the finger may be mounted in the disc in the manner of a plunger which is normally held retracted from the arm by spring means and is ejected by an energised electro-magnet or solenoid to assume the arm-engaging position shown in the drawing. Alternatively, the finger may be left projecting from the top of the disc and the latter may be raised and lowered by electro-magnetically energised and/or controlled means to move the finger into and out of the arm-engaging position.

If desired a disc 39 may be provided with a radial projection which, on each revolution of the disc operates spring contacts in a counting circuit.

In order to facilitate the placing of non-uniform letters or packets in position for ejection, it may be found desirable to provide guiding means which are more positive in action than the guide plates S. The additional means for this purpose shown in Figs. 7 to 10, while for convenience described in connection with those figures, will be understood to be applicable to the device described in connection with Figs. l to 5.

Referring again to Figs. 7 to 10 therefore, the gearing described with reference to the earlier figures for driving the snatch rollers, serves also to drive a bevel pinion 42 fixed to the end of a shaft 43 carrying a worm gear 44 which meshes with gear wheels 45 and 46. These gear wheels are mounted on spindles 47, 48 which, at their upper ends carry rollers 49 and 50 respectively, the positions of the rollers coinciding with slots in the guide plates and through which they pass into lightly abutting relationship. The spindles 47 and 48 are carried by brackets 51 and 52 which are pivotable about the axis of the shaft 43 and are provided with return springs 53 and 54 re- 6 spectively. One end of each of these springs is anchored to the angle bars 1, 1a, the other end being attached to its associated bracket. A self-centering link 55 is provided with pins 56, 57 which engage sockets (not shown) in the brackets 51 and S2 respectively when the assembly is in the normal horizontal position.

When an article other than a thin strictly fiat article is urged between the rollers 49 and 5t), it will tend to rock the brackets carrying the roller spindles but the action of the return springs will cause the article to be held by the rollers substantially centrally within the stall 6.

The energisation of the solenoid or other electromagnetic means for controlling the ejecting devices is under the control of the operator of the letter sorting machinery and it will be appreciated from the preceding description that a high degree of accuracy in control of the instants of release and ejection of letters can be achieved.

We claim:

1. In combination, a travelling conveyor means, and a device for ejecting postal letters and like flat articles from a position of rest and depositing each said ejected article on edge upon said travelling conveyor means, at a given instant of time determined by selective control means, said device comprising an article support consisting of a moving base adapted to travel in the direction in which said article is to be ejected, and upon which said article rests on edge, and mutually spaced upwardly extending guide members between which said article is carried by said moving base, pivotally mounted stop means arranged to swing across said moving base to form a barrier extending transversely of the path of movement of said article resting on edge on said moving base and to restrain said article from being carried along with said moving base beyond said barrier, electro-magnetically controlled means for swinging said stop means away from the path of movement of said article to release said article to move immediately with said moving base, ,spring means arranged to return said displaced stop means into position again to form said barrier behind said article so released, said stop means being actuated independently of the movement of said travelling conveyor means, and further means for facilitating and continuing the movement imparted to said released article by said moving base in order to transfer said article from said moving base on to said travelling conveyor means.

2. The combination claimed in claim l, wherein said electro-magnetically controlled means for swinging said stop means away from the path of movement of said article resting upon said moving base comprises a solenoid bobbin, a plunger associated with said solenoid bobbin, said plunger being arranged in relation to said stop means so that when said solenoid bobbin is energized said plunger is displaced and moves said stop means from r the path of movement of said article resting upon said moving base to release said article immediately to move with said moving base.

3. The combination claimed in claim l, wherein said moving base of said article support comprises a driven conveyor belt, and wherein said further means for facilitating and continuing the movement of said article from said moving base to said travelling conveyor means comprise co-operating resilient rollers at least one of which is power driven, said `co-operating rollers being disposed to receive said article therebetween and then to co-operate in transferring said article from said moving base on to said travelling conveyor means.

4. The combination as claimed in claim l, wherein said moving base of said article support comprises a driven endless conveyor band, and wherein said further means for facilitating and continuing the movement of said article from said moving band to said travelling conveyor means comprise co-operating resilient rollers at least one of which is power driven, said co-operating rollers being disposed to receive said article therebetween and then co-operate in transferring said article from said moving 7 base on to said travelling conveyor means, and including yieldingly mounted rotatory guide members for supporting an article resting on edge on said conveyor band and for facilitating the article-moving action of said rst mentioned co-operating resilient rollers.

5. In combination, a travelling conveyor means and a device for ejecting postal letters and like llat articles from aposition of rest and depositing each ejected article on edge .upon thesaid travelling conveyor means at a given instant of time determined by selective control means, said device comprising a container or stall to which the articles are fed one by one, and having a moving base, a pair of spaced guide members extending upwardly therefrom and adapted to support the article in a substantially upright position resting on edge on said moving base, the said base moving towards one end of the container in the direction in which the article is to be ejected, a stop member extending transversely of the base adjacent said one end of the container outwardly therefrom and adapted normally to restrain the article from moving with the moving base substantially beyond said one end of the container, and to be-moved out of the path of movement of the article upon actuation of said selective control means to permit the article to move with the said moving base outwardly from said one end of the container, and a pair of continuously rotating co-operating resilient rollers supported above said moving base adjacent said one end of the container for rotation in a plane parallel to the base and adapted to receive therebetween an article moving with the said base so that upon said movement of said stop member the article is fed by the moving base into the bight of the said co-operating rollers to be ejected thereby so as to be deposited on edge upon the said travelling conveyor means.

6. The combination as claimed in claim wherein the said moving base comprises a driven endless conveyor band, and the said guide members include a pair of cooperating guide rollers supported above the said moving base for rotation in a plane parallel thereto and yieldingly urged into peripheral engagement so that the bight of the rollers is positioned substantially centrally transversely of the moving base whereby an article resting on edge on said base is supported in a substantially upright position between said co-operating guide rollers to be urged thereby outwardly from said one end of the container upon movement of said stop member out of the path of movement of the article.

7. In combination, a travelling conveyor means and a device for ejecting postal letters and like flat articles from a position of rest and depositing each said ejected article on edge upon said travelling conveyor means at a given instant of time determined by operator controlled selective control means, said device comprising a moving base adapted to support an article on edge, and to travel in the direction in which the article is to be ejected, mutually spaced guide members extending upwardly from said base and adapted to support the article in a generally upwardly extending position, ivotally supported stop means adapted for pivotal movement from a first position extending'across the path of movement of the article resting on edge on said base to prevent the article from being carried along by said moving base, to a second position permitting the article to be carried along by the base, means normally urging said stop means to said lirst position, electro-magnetically controlled means for effecting movement of said stop means from said iirst to said second position to release said article for movement with the moving base, the said electro-magnetically controlled means being actuated under the control of said selective control means, and co-operating resilient rollers, at least one of which is power driven, supported above the moving base for rotation in a plane parallel thereto and disposed adjacent said stop means for receiving the said article when released by said stop means and to eject the said article to rest on edge on said travelling conveyor means.

8. The combination as claimed in claim 7 wherein the said moving base comprises a driven endless conveyor band, and the said guide members include a pair of cooperating guide rollers supported above said base for rotation in a plane parallel thereto, means yieldingly urging said rollers into peripheral engagement so that the bight of the rollers'is positioned substantially centrally transversely of the said moving base, and driving means tor one of said rollers, whereby an article resting on edge on said moving base is supported in a generally uprightV position between said guide rollers to be urged thereby in the said direction of ejection upon releaseot said article by movement of said stop means to said second position.

9. The combination claimed in claim 7, wherein said stop means comprise a barrier pivotally mounted and arranged so as normally to extend above and across said moving base, spring means which normally retain said barrier in position across said moving base, an electromagnetic solenoid bobbin, a solenoid plunger mounted in relation to said bobbin and said barrier so that when said bobbin is energized said plunger displaces said barrier from the path of movement of said article resting upon said moving base, said barrier being disposed in relation to said moving base so that said barrier moves ahead of said article whilst remaining in contact therewith in the initial part of said displacement of said stop means.

l0. The combination claimed in claim 7, wherein said stop means include a gate pivotally mounted so as normally to extend above and across said moving base, spring means which normally retain said gate in position across said moving base, a mechanically driven travelling member, a projection carried by said mechanically driven travelling member to engage and rotate said gate about vits axis thereby withdrawing said gate from the path of said article resting upon said moving base, said projection being withdrawable into an inoperative position when not required to displace said gate, and electro-magnetic controlling means comprising a solenoid device for moving said projection from one to the other of said alternative positions as required.

References Cited in the tile of this patent UNITED STATES PATENTS 1,602,753, Davis Oct. 12, 1926 1,992,349 Beardsley Feb. 26, 1935 2,016,268 Griffith Get. l, 1935 2,211,765 Davidson Aug. 26, 1940 2,371,926 Schmitt Mar. 20, 1945

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