US2421690A - Reciprocable means for automatically moving a series of articles in tandem through a drying chamber - Google Patents

Description

June 3, 1947. v. c. ENsoR ETAL 7 2,421,690

RECIPROCABLE MEANS FOR AUTOMATICALLY MOVING A SERIES OF ARTICLES IN TANDEM THROUGH A DRYING CHAMBER Filed Sept. 8, 1944 3 Sheets-Sheet 1 FIG.

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RECIPROCABLE MEANS FOR AUTOMATICALLY MOVING A SERIES OF ARTICLES IN TANDEM THROUGH A DRYING CHAMBER Filed Sept. 8, 1944 3 Sheets-Sheet 2 E 0. J0 NS TON June 3, 1947- v. c. ENSOR ETAL 2,421,690

RECIPROCABLE MEANS FOR AUTOMATICALLY MOVING A ssnms 0? ARTICLES IN TANDEM THROUGH A mums cnmssn Filed Sept. 8, 1944 3 Sheets-She et 3 477ORMSV which has an entrance door ll Patented June 3, 1947 RECIPROCABLE MEANS FOR CALLY MOVING A SERIES OF AUTOMATI- ARTICLES IN TANDEM THROUGH A DRYING CHAMBER Vernon C. Ensor, Woodlawn,

Johnston, Towson, Electric 1 Company,

and Fred D.

Md., 'assignors to Western Incorporated,

New York.

N. Y., a corporation of New York Application September 8, 1944, Serial No. 558,186 7 Claims. (Cl. 34-53) This invention relates to drying apparatus and more particularly to drying apparatus in which articles are subjected to a drying cycle of at least a predetermined length.

In the manufacturing of some types of insulated cables it is necessary to thoroughly dry the core portions of the cables before insulation is applied thereon. Such portions must be dried for a minimum period of time in order to make certain that the desired degree of dryness is obtained. In apparatus heretofore known for drying core portions it is difllcult for operators to ascertain when the core portions have been dried the required period of time and to prevent the core portions being dried from being removed from the apparatus before the expiration of the required minimum period of drying.

An object of the invention is to provide new and improved drying apparatus.

An apparatus constituting one embodiment of the invention includes an elongated oven having an entrance at oneend and an exit at the other end. There are provided means for ,carrying a plurality of articles in tandem through the oven and means for actuating the carrying means to present an article at the exit of the oven at a predetermined period of time after the next previous article has been presented at the exit.

A complete understanding of the invention may be obtained from the following detailed description of a specific embodiment thereof, when read in conjunction with the appended drawings, in which:

Fig. 1 is a fragmentary, top plan view of an apparatus embodying the invention;

Fig. 2 is a fragmentary, front view of the apparatus;

Fig. 3 is an enlarged, fragmentary, sectional view of the apparatus taken 3-3 of Fig. 1;

Fig. 4 is an enlarged, fragmentary, sectional view of the apparatus taken 4-4 of Fig. 2;

Fig. 5 is an enlarged, fragmentary, vertical sectional view of a portion of the apparatus, and

Fig. 6is a diagrammatic view of an electrical circuit suitable for use in controlling the operation of the apparatus.

Referring more in detail to the drawings, there is illustrated therein an apparatus for drying core portions of cables prior to the formation of insulating coverings thereover. This apparatus includes an elongated oven I0 (Figs. 1 and 2), slidable along slidably supported vertical on line vertical a rod l2 and an exit door IS on line a pair of hooks 24-24 at one when closed. the oven l0.

upon arod H. The exit door I3, covers an exit opening is formed in A ramp I6 is provided in the oven identical with the ramp IS,

l1-l1 positioned in the oven III are supplied with steam from a suitable source of steam (not shown), and serve to heat the interior of the oven I 0. v

A pair of channel-like tracks 20 and 2| (Fig. 4) extend longitudinally in the oven Ill. The tracks 20 and 2| serve to receive wheels 22-22 rotatably mounted on dollies 23-23 (Fig. 2). The dollies are designed to carry reels. 26-26 containing supplies of core portions which are to be dried. Each of the dollies is provided with end thereof, which connect the dollies together in a train extending from the entrance end to the exit end of the oven, which train is in effect a conveyor. Each dolly also has a pair of abutment plates 25-25 (Fig. 4) positioned near the forward end thereof.

. When a dolly 23 is in front of the exit door l3,

that is, in the position designated A in the drawings, it is accessible to an operator of the apparatus and the operator can remove the dolly readily. The dolly position next adjacent to position A to the left thereof, as seen in Fig. 1, is designated position B and the dolly position just to the left of positionB is designated position C. The dollies in the oven l0, including that in position B and those extending therefrom to the entrance end of the oven, and the reels carried thereby normally are inaccessible to the operator and cannot be removed from the oven until they are moved successively to position A.

A carriage 30 (Fig. 3) provided with supporting rollers 3l-3l is mounted for reciprocation along a trackway 32, which is positioned below the tracks 20 and 2|. The carriage 30 normally is located under a dolly 23 in position B and may be moved'to a point below position A and back to its normal location. A pair of dogs 33-33 are counter-balanced on a pair of pins 34-34 secured adjacent to the end of the carriage 30 nearest to the exit. The dogs 33-33 may be rotated in a clockwise direction, as viewed in Figs. 3 and 5, so that the upper ends thereof clear the abutment plates 25-25 of a dolly in position B and these plates are struck by the dogs when the carriage 30 is moved to the left relative to the dolly. However, when the upper ends of the dogs 33-33 clear the plates 25-25, the dogs are swung to vertical positions by the heavier lower portions Y posits to that in Fig. 3, the

Fig. 3.-

, opposite ends of dotted line position.

movement opens a rear secured to. the upper 3 thereof, which movement is limited by a bar 85. Thus, when the carriage 88 is moved to the right as viewed in Fig. 3, the upper ends of the dogs "-88 engage the abutm'ents 25-25 of the dolly 28 in position B, and this dolly is moved to the right toward position A with the, carriage. Since the dollies are connected, together by the hooks 24-24, all the dollies are moved to the' right with the end dolly.

A pair of dogs 81-81 (Fig. 3), which are identical with the dogs mounted near the end of the carriage 88 opcarrying the dogs 81-81, and when is in its full line position, as shown lower portions of the dogs 81-81 strike an abutment 88, which is secured to the oven in a position between the tracks Thus, when the carriage is so positioned, the dogs 81-81 are held against rotation by the abutment 88 andstrike the abutment plates 25-25 of the dolly in position C it an attempt is made to move the dollies menu lly to the right as viewed in the carriage A ram 42 fastenedto a piston (not shown) .enclosed in a pneumatic cylinder 48 is rigidly secured to the bar 85. A conventional four-way valve 44 issupported on the cylinder 48 and is provided with a solenoid 45 and a solenoid 48,

which operate the valv 44,

of valve, and is connected by pipes 48 and H to the cylinder 48. When the solenoid 45 is energized, the valve 44 is actuated to supply air into the cylinder 48 so" as to cause the piston in the cylinder 48 to draw the rain to the right, as'viewed in Fig. 3, whereby the carriage 88 is drawn along the track 82 from its full line position, as shown in Fig. 8', to its This movement of the carriage 88 moves the dolly in position Bfrom position B to position A.' When the solenoid 48 is energized, the ram 42 is thrust to the left, as viewed in Fig. 3, and the carriage 88 is moved from its dotted line position, as shown in that figure, to its full line position, the dogs 3. The dogs 88-88 then prevent the train of dollies from being moved to the left, while the dogs 81-81 prevent the dollies from being moved to the right. I

. A rod 41 (Fig. 3) is secured to the bar 85 and rests in a U-shaped guide 48. When the carriage 88 is moved to its full line position, an arm carried by the rod 41 strikes a springressed arm 58 and moves the arm 58' from its position shown in dotted lines to that-shown in "full lines, which limit switch I.

A curved arm 52 (Fig. 3) is rigidly mounted on a vertical rod 58, which is rotatably mounted in a pair of bearings 54-54 secured to the wall of the oven I8, and a kicker 55 (Fig. 1) is rigidly end of the rod 58. A spring- 58 of a forward limit switch 51 northe kicker 55 to its full line position. as shown in. Fig. 1. In this position the arm 52 is in the path of a dolly'in position A, and when a dolly is moved forward from position B to position A by the carriage 88, it and moves it to its dotted line position, whereby the kicker 55 moves the spring-pressed arm 58 to-its dotted lineposition to actuate the forward limit switch 51.

The forward limit switch .51 (Figs. 1 and 6) includes a pair of contacts and N and a contactor 82. when the spring-pressed arm 58 is in dolly in position pressed arm maily urges 88-88, are pivotally The four-way valve. 44 is a standard bleeder-valve-controlled type 88-88 and 81-81 clearing the plates 25-25 of the strikes the arm 52' s by the'contactor 28 and 2I.'

its full line position, as shown in Fig. 1, the contactor 82 is in engagement with the contact 88. When the spring-pressed arm 58 is moved to. its dotted line position, the contactor 82 is brought into engagement with the contact 8|.

The contact 88 (Fig. 8) is connected by a conductor 88 to a contactor 84 of a relay 85. when the relay is not energized, the contactor 84 is in engagement with a contact 88 of A conductor 18 serves to connect the contact 88 to a contactor H of a normally open relay 12. The relay 12 includes a contact 18. which is engaged 1I when the relay 12 is actuated. The contact 181s connected by a conductor 14 to a winding 15 of the solenoid 45.

A conductor 18 (Fig. 6) connects the winding 15 to a conductor 11, which is connected to a winding 88 of the solenoid 48-. A conductor 8I connects the winding 88 tom contact 82 of the relay 85. A contactor 88 of the relay 85 is brought into engagement with the contact 82 when a winding 84 of the relay is energized. The contactor 88 is connected by conductor 81 to a conductor 88 of a power line 88., The conductors 88 and 81 are connected by a conductor 88 to the con-- tactor 82. The power line 88 includes a conductor 8i, which has a manually operable switch 82 therein and is connected to a conductor 88.

The conductor 88 (Fig. 6) is connected to a conductor 84, to the conductor 11, and to one end of a filament 85 of an incandescent lamp 88. The other end of the filament 85 is connected by a conductor I88 to a conductor IN. The conductor IN is connected to the contact 8| of the limit switch 51 and to a normally closed contactor I82 of the limit switch 5I. The con-' tactor I82 is normally in engagement with a con.- tact I88, which is connected by a conductor I84 to the winding 84 of the relay 85. The contactor I82 is connected by a conductor I85 to a contact I88 of the relay 85. A contactor II8 of the relay- 85 serves to engage the contact I88 when the winding 84 is energized, and is connected by a conductor III to the conductor 81.

The conductor II2 of a conventional timer II8. A conductor .4 serves to connect an end of a clutch coil II5 of the timer to the conductor 84, and a conductor II8 connects the other end of the clutch coil II5 to a conductor I28. which is connected to the motor N2 of the timer and to the contactor 84.

The conductor I28 has therein a normally closed safety limit switch I2I, which is opened by the timer H8 in case of failure of the apparatus and thereby prevents damage to the apparatus.

The timer II8 (Fig. 6) includes a normally open main contact I22, which is conductor I24 to a winding I25 of the relay 12 and by a-conductor I28 to the conductor 84. A conductor I28 connects the winding I25 to the conductor 88. A housing I21 (Fig. 2) mounted on the top of the oven I8 serves to enclose the relays 85 and 12 and the timer H8, and the lamp 88 and the switch 82 are supported thereby in obvious and accessible positions.

In the operation of the apparatus described hereinabove, the dollies 28-28 (Fig. 1) and the reels 28-28 are placed successively in the oven I8 to fill the oven, which is heated by steam-supplied to the steam pipes I1-I1, and the switch 82 (Fig. 8) is closed. After the apparatus is-in its normal operating cycle with the oven I8 filled with dollies except for position A, which is vacant. and the timer II8 has been in operation for a predetermined period of time, the main contact the relay 85. 1

84 leads to a synchronous motor connected by a and the conductor 14.

. solenoid 46 causes the valve 4'4 to be actuated to 5 V I22 is closed'by the timer. The closing of the main contact closes the circuit to the winding I26 01 the relay 12 and the winding is energized by current from the power line 90 through the conductors 86 and I26 to the winding I26, and through the conductors 9|, 93, 94 and I23, the main contact 22, and the conductor I24.

When the winding I26 is energized, the winding 16 of the solenoid 45 is .supplied with current from the power line 90 through the conductors 9|, 93, I1 and 16, and through the conductors 86 and 88, the contactor 62, the contact 60, the conductor 63, the contactor 64, the contact 66, the conductor 10, the contactor II, the contact 13, The energization of the supply air under pressure to the left hand end of the cylinder 43, as viewed in Fig, 2, and to exhaust the right hand end thereof, whereby the ram '42 draws the carriage 30 to its dotted line position, as shown in Fig. 3. As the carriage 30 moves to the right the dogs 33--33 engage the dolly in position 13 and move that dolly to position A. The dolly advanced by the carriage 30 pulls the entire train of dollies to the right through a distance dolly.

As the carriage 30 is movedto the-right, as viewed in Fig. 3, the arm 49 is moved out of engagement with the spring-pressed arm 50, which moves to its dotted line position, thereby causing the engagement of the contactor |02 (Fig 6) and the contact I03. When the dolly moved from position B to position A engages the arm 62 and moves it from its full line position toits dotted line position, as shown in Fig. 1, the forward limit switch 51 is actuated and the contactor 62 is moved out of engagement with the contact 60, whereby the circuit to the winding 15 of the solenoid 45 is broken, and the contactor 62 is moved into engagement with the contact 6|.

As soon as the contactor 62 (Fig. 6) engages the contact 6|, the lamp 96 is supplied with current through the conductors 9| and 93, and the conductors 86 and 88, the contactor 62, the contact 6|, and the conductors IN and M0, and the filament 95 of the lamp is lighted. The lighting of the lamp 96 indicates that a dolly 23 and its reel 26 are in position A, and can be removed from the oven l0.

Upon the engagement 6) and the contact 6|, lay 65 of the contactor 62 (Fig. the winding 84 of the reis energized through the conductors 9|, 93 and 94, and through the conductors 86 and 88, the contactor 62, the contact 6|, the conductor l0|, the contactor I02, the contact I03, and

, the conductor I 04. The energization of the winding 84 moves the contactors H0 and 83 into engagement with the contacts I06 and '82, respectively, and moves the contactor 64 out of engagement with the contact 66.

When the engagement between the contactor 64 (Fig. 6) and the contact 66 is broken, the circuits to the winding 15 of the solenoid 45, to the clutch coil H5, and to the motor H2 of the timer equal to the length of one then causesthe valve 44 to be 6 the conductors 9|, 93 and I1, and through the conductors l6 and 81, the contactor 83, the contact 82, and the conductor 8|. The solenoid 46 moved to the position in which it directs air under pressure to the right hand end of the cylinder 43, as seen in Fig. 2, and exhausts air from the opposite end thereof, whereby the carriage 30 is moved back along the trackway 32 to its full line position, as shown in Fig. 3. As the carriage is so moved, the dogs 31-31 and 3333 rotate as they 'are moved past the abutment plates 26-26 of thedolly in position B so that the carriage is not obstructed in its travel. When the carriage reaches its full line position, the dogs 31-31 engage the abutment 33 and are prevented from rotating in a clock-wise direction. Also, when the carriage 30 reaches its full line position, the arm 49 strikes the spring-pressed arm 60 of the rear limit switch 6|, which causes the engagement between the contactor I02 (Fig. 6) and the contact, I03 to be broken, whereby the winding 84 of the relay 65 is de-energized.

When the winding 84 of the relay 61 (Fig, 6) is de-energized the contactor 64 engages the contact 66 and the contractors H0 and 83 are disengaged from the contacts I06 and 82, respectively, whereby the solenoid 46 is de-energized. However, the valve 44 continues to supply air under pressure to the right hand end of the cylinder 43 and the carriage 30 is held in its full line position.

The circuit to the timer motor 2 (Fig. 6) is closed at this time except for the contact 60 and the contactor 62, which are out of engagement.

Upon seeing the lighted lamp 96 (Fig. 2) an operator removes from the oven I0 the reel 26 and the dolly 23 which are in position A, and places 3 are broken. The timer 3 then resets to;

zero, whereby the main contact I22 is opened which breaks the circuit to the winding I25 of the relay l2 and the engagement :between the contactor II and the contact 13 is broken.

' When the engagements are effected between the contactor 0 (Fig. 6) and the contact I06, and the contactor 83 and the contact 62, the winding 60 of the solenoid 46 is energized through another dolly and reel in the oven at the entrance end thereof, the dolly which is inserted being hooked to the next adjacent dolly in the oven. Thus, the train. of dollies is maintained throughout the length of the oven |0 except for position A, which is vacant.

The removal of the dolly from position A permits the arm 52 to be swung to its full line position, as shown in Fig. 1,, by the spring-pressed arm 56, and the contactor 62 of the forward limit switch is moved into engagementwith the contact 60. This causes the lamp 96 to be darkened and completes the circuit to the motor 2 and the clutch coil H5 of the timer 3. The timer motor I I2 is supplied with current from the power line through the conductors 9|, 93 and 94, and through the conductors 86 and 88, the contactor 62, which is in contact with the contact 60 when no dolly is in position A, the contact 60, the conductor 63, and the conductor |20 which includes the limit switch |2I, which is closed. The clutch coil H5, which is in parallel with the motor. I 2, also is energized at this time.

Since the valve 44 (Figs. 1 and 2) at this time is in a position in which air under pressure is supplied to the right hand end of the cylinder 43, as viewed in Fig. 2, and the carriage 30 is held below position B, the dogs 3'|--31 then are held against the abutment 38 so that the dollies 23-23 cannot be moved forward manually far enough to place the end dolly in position A, which is the only position in which it can be removed from the oven l0 through the exit opening IS. The dollies cannot 'be moved to the rear because of the dogs 33-33.' Thus, none of the dollies in the oven may be moved manually along the tracks 20 and 2| to position A.

The main contact i2 determined period of ime after the start oi! the timer H3, which period is equal to the minimum period of time for drying the core portions on the reels 26-28 divided by the number of dollies 23-23 which may be contained in the oven ill. The timer '1 l3, of course, may be adjusted suitably.

While the main contact I22 (Fig. 6) is open the circuit to the winding I25 of the relay 1! is open and the contactor H and the contact 13 are out of engagement, whereby the circuit to the winding 15 of the solenoid 45 is open. H3 has operated for the predetermined period of time, it closes the main contact I22 and the cycle of operation described hereinabove is repeated.

The dogs 31-31 (Fig. 3) are held by the abutobstructing the movement of the dollies 23-23 when the carriage is in its rear position. Consequently, the dollies cannot be moved manually to position A and each remains in the oven Ill for the required minimum period of time of drying.

The apparatus described hereinabove is entirely automatic and an operator thereof need only insert the loaded dollies into and remove them from the oven l0. Consequently, while very little efiort and attention are required, each reel will be dried for the required minimum of time. I

What is claimed is:

1. In a drying apparatus including an elongated enclosure having an entrance and an exit, reciprocable means movable from a starting position to a forward position for moving a series of articles arranged in tandem through the enclosure; means for driving the moving means and means for preventing movement of articles moved by the moving means except by the moving means, means for controlling the operation of the driving means which comprises a starting solenoid for causing the driving means to drive the reciprocable means from its starting position to its forward position to move a series of articles toward the exit end of the enclosure, a reversing solenoid for causing the driving means to drive the reciprocable means from its forward position to its starting position, and a limit switch positioned near the exit of the enclosure and servin when engaged by an article moved by the reciprocable means to the exit-to tie-energize the starting solenoid and to energize the reversing solenoid.

2. In a drying apparatus including an elongated enclosure having an entrance and an exit, reciprocable means movable from a starting position to a forward position for moving through the enclosure a series of articles arranged in tandem and means for driving the moving means. means for controlling the movement of articles positioned in the enclosure which comprises means for preventing movement of the articles except by the moving means, a startingsolenoid for causing the driving means to drive the reciprocable means from its starting position to its forward position to move a series of articles toward the exit end ofthe enclosure when energized, a reversing solenoid for causing the driving means to drive the reciprocable means from its forward position to itsstarting position when energized, a switch serving when actuated to deenergize the starting solenoid and to energize the reversing solenoid, means positioned near the exit of the enclosure for actuating the switch when engaged by an article moved by the reperiod (Fig. 6) is open for a prefor reciprocating gaging the actuating means is removed from ciprocable means to the exit, means for de-energizing the reversing solenoid when the reciprocable means is moved to its starting P sition, a second switch for causing the energization of the starting solenoid, and a timer in circuit with the first switch and started when the article enthe exit of the enclosure for closing the second switch at the end of a predeterminedperiod of time after the article is removed.

3. In a drying apparatus including an elongated enclosure having an entrance and an exit, reciprocable means movable from a starting position to a iorward position for moving a -'series of articles arranged in tandem through the enclosure, means for driving the moving means and means for preventing movement of articles in the enclosure except by the moving means, means for controlling the operation of the driving means which comprises a starting solenoid for causing the driving means to drive the reciprocable means from its starting position to its forward position to move a series of articles toward the exit of the enclosure when energized, a reversing solenoid for causing the driving means to drive the reciprocable means from-its-forward position to its starting position when energized, a double throw limit switch positioned near the exit of the enclosure serving when engaged by an article moved by the reciprocable mearisto the exit to de-energize the starting solenoid and energize the reversing solenoid, means for de-energizing the reversing solenoid ,when the reciprocable means is moved to its starting position, a starting switch in series with the starting solenoid for causing its energization, and a timer started when the article moved to the exit of the enclosure is removed therefrom for closing the starting switch a predetermined period of time after the article at the exit is removed. 4

4. In a drying apparatus including an enclosure having an entrance and an exit, a track extending from the entrance to the exit of the enclosure,

a series of connected article-carrying dollies movable along the track, a carriage having ratchet means thereon for engaging one of the dollies when moved toward the exit of the enclosure to move the dollies therewith and pneumatic means the carriage along the track a distance equal to the length of one of the dollies, means for controlling the movement of the dollies which comprises means for preventing move-' ment of the dollies when the carriage is not reciprocated, a valve for controlling the pneumatic means, the valve so as to cause the pneumatic means to move the carriage toward the exit of the enclosure when energized, a starting switch for causing the energization of the starting solenoid when closed, a reversing solenoid foractuating the valve to cause the pneumatic means to move the carriage away from the exit of the enclosure 'when energized, a timer for closing the starting switch after it has-run a predetermined period of time, a reversing switch serving to stop the timer, de-energize the starting solenoid and energize the reversing solenoid when actuated and start the timer when unactuated, and means ositioned in the path of the dollies at a point adjacent to the exit of the enclosure for actuating the reversing switch when struck by one of the dollies moved to the having a starting solenoid for actuating move the dollies therewith and pneumatic means for reciprocating the carriage along the track a distance equal to the length of one of the dollies, means for controlling. the movement of the dollies which comprises means for preventing movement of the dollies when the carriage is not reciprocated, a valve for controlling the pneumatic means, starting solenoid to cause the pneumatic means to move the car riage toward the exit of the enclosure when energized, a starting switch for causin the energization of the starting solenoid when closed, a reversing solenoid for actuating the valve to cause the pneumatic means to move the carriage away enclosure when energized, atimer for closing the starting switch after it has run a predetermined period of time, a doublethrow switch serving to stop the timer, de-energize the starting solenoid and energize the reversto the exit, said double-throw switch serving to restart the timer when the dolly moved to the exit is moved out of engagement therewith.

6. In a drying apparatus including an elongated enclosure having an entrance and an exit, a train of connected dollies positioned in the enclosure and movable therealong, a reciprocable ratchet mechanism for moving the train of connected dollies toward the entrance or the enclosure a. distance equal to the length of one of the dollies at each reciprocation thereof and pneumatic means for reciprocating the ratchet mechanism, means for controlling the movement of the train of dollies which comprises means for preventing movement of the train of dollies relative to the enclosure when the train of dollies is not moved by the ratchet mechanism, a supply line associated with the pneumatic means, a. valve positioned in the supply line serving to cause the pneumatic means to move the ratchet mechanism toward the exit of the an advancing position and cause the pneumatic means to move the ratchet from the exit when in a reversing position, starting electromagnetic means for moving the valve to the advancing position, reversing electromagnetic means for moving the valve to its reversing position, a timer in circuit with the starting electromagnetic means for energizing that electromagnetic means after it has run a predetermined period of time, and a limit switch positioned so as to be engaged dollies which is moved to the exit of the enclosure and serving to stop and reset the timer, de-energize the starting solenoid and energize the reversing solenoid when so engaged.

7. In a drying apparatus including an elongated enclosure having an entrance a train of connected dollies positioned in the en-'- closure and movable therealong. a reciprocable ratchet mechanism for moving the train of connected dollies toward the entrance of the enclosure a distance equal to the length of one of the mechanism away and an exit,

' matic means for reciprocating the ratchet mech anism, means for controlling movement of the train of dollies which comprises means for preventing movement of the train of dollies relative to the. enclosure when the train of dollies is not moved by the ratchet mechanism, a supply line, a

four-way valve connecting the supply line to the I pneumatic means, a starting solenoid ior actuat for actuating the valve enclosure when in by the one ofthe 6o dollies at each reciprocation thereof and pneuing the valve to cause the pneumatic means to drive the ratchet mechanism toward the exit of the enclosure when energized, a reversing solenoid for actuating the valve to cause the pneumatic means to drive the ratchet mechanism away from the exit when energized, a starting relay including a winding and normally open contacts in series with the starting solenoid for energizing that solenoid when energized, an automatically resetting timer having, a motor and normally open timer contacts in series with the winding of the relay and serving to close the timer contacts a predetermined period of time after the timer is started, whereby the starting solenoid is energized a predetermined period of time-after the timer is started, a reversing relay having a winding and normally open contacts in series with the reversing solenoid for energizing the reversing solenoid when throw limit switch positioned in the path of the dollies at the exit of the enclosure and having a starting contact in series with the motor of the timer, a. reversing contact in series with the reversing relay-and a contactor normally in engagement with the starting contact thereof but movable out of engagement therewith and into engagement with the reversing contact thereof when the limit switch is engaged by one of the dollies moved to the exit 01 the enclosure, whereby the timer resets, the starting solenoid is deenergized and the reversing solenoid is energized when one of the dollies is moved to the exit, and a stopping limit switch having normally closed contacts in series with the winding of the reversing relay and positioned so that the contacts thereof are opened by the ratchet mechanism at the end of a reciprocation thereof, whereby the reversing relay is de-energized and the reversing solenoid is de-energized at the end of a reciprocation of the ratchet mechanism.

FRED D. JOHNSTON. VERNON C. ENSOR.

file of this patent:

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