US3613193A

US3613193A - Apparatus for mounting venetian blind slats

Info

Publication number: US3613193A
Application number: US797499A
Authority: US
Inventors: Bertil Westberg
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-02-09
Filing date: 1969-02-07
Publication date: 1971-10-19
Anticipated expiration: 1988-10-19
Also published as: NL6902090A; SE343914B; GB1262881A; DE1906178A1

Abstract

A VENETIAN BLIND ASSEMBLING APPARATUS FOR INSERTING VENETIAN BLIND SLATS IN ALIGNED OPENINGS IN CORD LADDERS. DURING INSERTION OF SUCCESSIVE SLATS, THE CROSS CORDS OF THE LADDERS ARE POSITIONED ALTERNATELY TO RESPECTIVELY ONE SIDE AND THE OTHER SIDE OF THE USUAL LIFT-CORD-RECEIVING HOLES FORMED IN OPPOSING END PORTIONS OF EACH SLAT. THUS, DURING MOUNTING OF THE LIFTING CORDS IN THE VENETIAN BLIND, THEY ARE INSERTED IN A ZIG-ZAG CONFIGURATION BETWEEN THE CROSS CORDS OF THE CORD LADDERS.

Description

APPARATUS FOR MOUNTING VENETIAN BLIND SLATS Filed Feb. 7, -1969 4 Sheets-Sheet 1 Oct. 19, 1911 B, 3,613,193

APPARATUS FOR IOUNTING VENETIAN BLIND SLATS Filed Feb. 7, 1969 4 Sheets-Sheet 2 FIG. l

FIGB FIG? F|G.8

Oct. 19, 1971 3,613,193

APPARATUS Fon uoUNTING VENETIAN BLIND sLATs Filed Feb. 1. 1969 a. wEs'rBERG 4 Sheets-Sheet 3 V n u 2| l lll-- l l lllllllll Il# Tl Il NI lr n Nl .Q. a Q. .B T Y N Y .l Qme @No mb@ O@ www--- T :Si @0E @J Naw I .r g 1 Thu |||d-||| ll l ||mN||||||| Od. 19, 1911 a, WES'BERG 3,613,1,3

APPARATUS FOR IAOUNTING VENETIN BLIND SLTS Filed Feb. 7. 1969 4 Sheets-Sheet L Fl 6.11v

FIG.12

A Ijlnted States Patent O1 ice 3,613,193 Patented Oct. 19, 1971 3,613,193 APPARATUS FOR MOUNTING VENETIAN BLIND SLATS Bertil Westberg, Rombergsgatan 32, Enkoping, Sweden Filed Feb. 7, 1969, Ser. No. 797,499 Claims priority, application Sweden, Feb. 9, 1968,

,746/68 Int. Cl. B23p 19/04 U.S. Cl. 29-24.5 9 Claims ABSTRACT OF THE DISCLOSURE Venetian blind assembling apparatus are known which insert the lifting cords zig-zag between the cross cords of the cord ladders supporting the individual slots. Venetian blinds assembled by means of this known type of apparatus exhibit good dimensional stability. In a known embodiment of this type of apparatus there is provided a lifting arm feeding individual slats from a starting position in which the lifting cord openings of the slat are positioned above the cross cords of the cord ladders to an upper position in which the assembled slats are collected. The successive positioning of the cross cords of the cord ladders to positions on one side or the other of the lifting cords openings in the individual slats is brought about by guiding the lifting arm in its upward movement in V- shaped or X-shaped tracks. As the one end of the lifting arm is journaled on a stationary pivot and as the other end of the lifting arm in its upward movement lifts the slats which together with the respective cord ladder section the slats will be angularly turned about the stationary pivot whereby the two longitudinal cords of the cord ladders will move with dilferent speed causing the cross cords to deviate from the horizontal position and, after a number of oscillations of the lifting arm, to interfere with the path in which the slats are inserted into starting position.

In order to eliminate this drawback the present apparatus is provided with a vertically disposed, rising and descending slat lifter adapted to lift slats from a starting position to an upper position in which the slats are collected, the plane through the longitudinal axis of symmetry of the slats all the time being horizontal. Due to this the longitudinal cords of the cord ladders are drawn upwardly in equal lengths whereby the cross cords always will remain in a horizontal position preventing the slat path from becoming blocked and enabling the apparatus to be operated continuously.

The object of the invention is an apparatus for mounting Venetian blind slats which by means of a slat feeder have been inserted into aligned openings in cord laders. The apparatus comprises a frame and slat mounting units which are preferably shiftable in the longitudinal direction of the frame and adapted successively to lift individual slats and cord ladders sections from a starting position to an upper position in which the mounted slats are stored. The apparatus is characterized by the fact that each slat mounting unit comprises a slat lifter adapted successively to lift individual slats and cord ladder sections from the starting position in a straight path to the upper position, a variator tripped by the slat lifter being adapted to position cord ladder guides in such a way that the cross cords of the cord ladders alternately are positioned to respectively the one and the other side of the lifting cord openings provided in the slats.

The slat feeder adapted to insert slats into aligned openings in cord ladders acts to trigger the slat mounting unit for lifting of individual slats synchronously with the substantially horizontal feeding of a slat from the slaf feeder.

As will appear from the following description the apparatus according to the invention is easily adjustable for assembling Venetian blinds of different types as far as width and length of the slats is concerned, such adjustment only requiring exchange of a few parts.

For a more detailed explanation of the invention reference is made to the enclosed drawings in which FIG. 1 is a plan view of the apparatus according to the present invention, FIG. 2 is an elevation of the apparatus, FIG. 3 is a plan View of the ataching plate of the mounting unit, FIG. 4 is a front elevation of the attaching plate shown in FIG. 3, FIG. 5 is a front elevation of the cord ladder guide, FIGS. 6, 7 and 8 are side elevations of the variator plate including its longitudinal connection with the cord ladder guide shown in FIG. 5, FIG. 9 is a partial plan view of a slat feeder in one position, FIG. 10 is a partial plan view of the slat feeder in another position. FIG. 1l is an elevation of the slat feeder and FIG. 12 is -a bottom view of the slat feeder.

As shown in FIG. l the apparatus according to the invention comprises a frame 1 Carrying Slat mounting units 2 and 3 for lateral shifting displacement along the frame. The number of slat mounting units 2 and 3 may be increased according to the number of lifting cord openings 6 provided on each slat. Slats 5 are advanced in a path from a slat feeder 4 to be brought to a standstill by suitable arrangements, not shown, as soon as the lifting cord openings 6 are in position above cord ladder guides 7 provided on each slat mounting unit 2, 3. As soon as the slat feeder 4 has discharged a slat in its entire length the slat feeder 4 will transmit an electric signal actuating an electromagnet 8 which in turn actuates a link device 9 provided on a rod 10 rotatably journaled in the frame and provided with a longitudinal track 11. Suitably the rod is journaled in ball bearings 12 at both ends of the frame. A plate 13 adapted to slide along one side of the frame is provided with an opening 14 through which an arm 15 extends. Arm 15 is adapted t0 slide along rod 10 and to engage track 11 whereby the arm will be forced to turn together with rod 10 without sliding movement in an axial direction when electromagnet 8 is actuated and thereby via link device 9 transmits a turning movement to rod 10. Plate 13 is welded to a mounting plate 16 (FIGS. 2, 3 and 4). A slat lifter 18 is adapted to move through a vertical bore 17 of the mounting plate, said slat lifter at its lower end being pivotally connected to the outer end of arm 15. The slat lifter 18 is guided in its vertical rising and descending movement by suitable guides (not shown). By means of the slat lifter 18 the slat supported on a slat carrier 20 is lifted from a starting position (shown in full lines in FIG. 2) to an upper position (shown in broken lines in FIG. 2) due to the swinging movement of arm 15. A guide pin 19 provided at the upper end of slat lifter 18 acts via a variator 33 and a link device 30, 40 to move the cord ladder freely suspended in a cord ladder guide 7 alternately to one side and the other side of the lifting cord opening 6 depending on successive downward movements of the slat lifter 18. In the Starting position the slat carrier is received in a recess 21, provided in the mounting plate 16. The upper curved edge of the slat carrier 20 in the starting position is disposed below a slat track 22 guiding the slat in its movement from the slat feeder 4 to the starting position. On either side 0f the

slat track rods

73, 74 are provided delimiting a storing compartment for assembled slats. The rods are provided with a spring-biased dog 75 supporting every lifted slat in the upper position. Rod 74 is suitably pivoted to the upper end of rod 73 whereby after assembling of a sufficient number of individual slats to form a Venetian blind such assembly easily may be removed from the storing space opened by outward swinging of rod 74.

In front of recess 21 mounting plate 16 is provided with a further recessed portion 23 and a bore 24 receiving the cord ladder guide 7. Cord ladder guide 7 comprises a circular rod 7 having a recessed portion 25 (FIGS. 3 and 5), two tube sections 26 being provided at the transverse edges of this recessed portion 25 on rotatably journaled elements 27. Tube sections 26 are longitudinally slotted at 28, the cross cords of the cord ladders freely moving through these slots. When a slat is in the starting position the lifting cord openings 6 of the slat are positioned substantially above tube sections 26. However, in the starting position tube sections 26 are not upright but angularly enclined in relation to a vertical plane extending perpendicularly to the longitudinal axis of symmetry of the slats. When the slat is lifted by a Carrier 20 the upper side of the slat will Contact a cross Cord of the cord ladder. Due to the inclination of tube sections 26 in relation to said plane the cross cord in question will be disposed to one side of the lifting cord opening of the slat. During the upward movement of the slat, which movement of course corresponds to the spacing between two successive cross cords, the cord ladder guide 7 all the time is inclined at the same angle to said vertical plane. At the end of the upward movement the lifting cord openings of the slat are passed by a needle 29 0n which the lifting cord of the Venetian blind is held. Thus, the cross cord of the cord ladder in the upper position will be permanently positioned to one side of the lifting cord opening. D-uring the downward movement of the slat lifter 18 guide pin 19 will Shift a variator 33 to a different stable equilibrium position and during this movement a link device 30, 40 will position the cord ladder guide '7 in a new starting position, in which tube sections 26 are inclined at the same angle as before in relation to said vertical plane perpendicular to the longitudinal axis of symmetry of the slat, however, on the other side of said plane. Thus, tube sections 26 now have shifted over the cross cord of the cord ladder to the opposite side of the lifting cord opening 6 compared to the position of the preceding cross cord on the slat now supported lowermost on dogs 25. Slat lifter 18 and thereby the slat supported on slat carrier 20 are rising and come into lifting contact with the cross cord of the cord ladder7 causing the needle tip. 29 to pass through lifting cord opening 6 for insertion of the lifting cord, the cross cord of the cord ladder in this instance being positioned to the opposite side of the lifting cord opening as compared to the position of the cross cord on the slat lifted immediately before. At the end of the rising movement the slat will laterally displace dogs 75 which during the continued upward movement of the slat carrier 20 will return to the position according to FIG. 2. During the subsequent descending movement of the slat carrier the dogs 75 will intercept the slat lifter recently and hold both slat and the previously assembled slats overlying the latest slat.

The variator 33 will be described by reference to FIGS. 2, 6, 7 and 8. The variator 33 comprises a stationary support rod 31 having a stud 32 about which a variator plate 33 is adapted to swing between two stable equilibrium position (FIGS. 6 and 8). A second stud 34 is attached to the lower part of variator plate 33, a guide plate 35 being pivotable about said second stud in dependence on the rising and descending movement of the guide pin 19. The guide plate 35 is V-shaped with the tip pointing upwardly, an attachment pin 38 for a coil spring 41 being attached to the tip. The attachment pin is movable within an arcuate opening 39 in the variator plate 33. While one end of coil spring 41 is attached to the end of attachment pin 38 the other end of the spring is attached in a suitable way to the support rod 31 below the level of attachment pin 38. Due to this and to the curved shape of opening 39 the variator plate 33 will have two stable positions of equilibrium. Pivotally attached to the lower part of variator plate 33 is a link arm 40 which at the free end is pivotally connected to the free end of a link arm 30 the other end of which is attached to the cord ladder guide 7.

When the slat lifter 18 is in the starting position (FIG. 2), guide pin 19 of slat lifter 18 is in contact with a guide edge 37 of guide plate 35 (FIG. 6). When guide pin 19 moves upwardly to the position shown in FIG. 7, the stable equilibrium of the variator plate in one of its two stable positions of equilibrium will not be disturbed and, accordingly, the link arrangement 30, 40 will not alter the position of ladder cord guide in which the upper ends of tube sections 26 are positioned to one side of the lifting cord openings 6 in the slats. However, when the slat lifter 18 after a rising movement returns to its starting position, guide pin 19 will engage the other guide edge 36 of guide plate 35 and during continued downward movement of guide pin 19 guide plate 35 will be forced to pivot about pin 34. Due to this the variator plate will be tipped over from the one stable equilibrium position to the other. In this new starting position the upper ends of tube sections 26 are positioned to the opposite side of lifting cord opening 6 and cord ladder guide 7 will maintain this position throughout the next rising movement of slat lifter 18. Due to the fact that slat lifter 18 and thereby also slat carrier 20 are moving in a straight path upwardly (and downwardly) the two longitudinal cords of the cord ladder always will be pulled upwardly in identical increments whereby the cross cords will be prevented from extending obliquely in relation to the slat path in a position in which they might form an obstruction preventing the slats from being transferred to starting position.

By reference to FIGS. 9, 10, 11 and 12 a description will be given of the arrangement combined with the slat feeder for controlling the actuation of electromagnet 8. The slat feeder comprises a plurality of aligned motor driven

feed rollers

60, 62, 64, `66 operated by means of a common motor (not shown) via belts and pulleys (not shown). The rotational speed of the feed rollers may be controlled by adjusting the speed of the motor or by appropriate choice of the transmission ratio of the pulleys. Positioned between the feed rollers and arranged in pairs along the slat path defined by the feed roller are side guide pins 43 adapted to come into sliding contact with the edges of the slats 5 to guide the slats through the slat path. The side guide pins 43 are inserted into holes the spacing between which transversely of the guide path corresponds to the width of the slats actually handled. A stop element 44 comprising an adjustable plug extending downwardly into the slat path prevents slats in excess of one at a time from being fed forward towards the forward region 42 of the slat feeder. The apparatus may be adjusted for handling slats of a thickness different from a previously treated set of slats by vertically adjusting the plug of the stop element 44 in relation to the upper surface of feed roller 66, this surface preferably having a low coefficient of friction. Several slats may be placed one upon the other ahead of the stationary stop element to serve as a supply from which slats are extracted from below. Behind the stationary stop element 44 there is provided a first slat scanner 48 (FIGS. 9 and 10) comprising a vertical rod 48a, rotatably journaled and rigidly carrying a Z-shaped angular element 48b. One of the two parallel arms of said elements 48b carries a sleeve 53 which in its free end holds an outwardly spring-biased plug 54 or the like. At the free end of the other one of said parallel arms there is pivotally attached one end of a connecting rod 49, the other end of which is pivoted to the free end of a guide pin 50 which together with a further guide pin 51 (FIGS. ll and 12) is rigidly connected to a rotatably journaled vertical rod 55. A second slat scanner 47 comprises a roller freely rotatable on a short rod 47a. The short rod 47a is rigidly connected to the rotatably journalled rod 55. The second slat scanner 47 is springbiased in such a way that its roller intersects the slat path. When a slat engages the second slat scanner 47 to displace it laterally out of the slat path in a forwardly directed turning movement, such turning movement by means of the connecting rod 49 is transferred to the rst slat scanner 48 which is adjusted into a second position in which the sleeve 53 is turned to such a position that said outwardly extensible plug 54 abuts against the slat passing alongside (cf. FIG. 9). When this slat has passed beyond the first slat scanner 48 the spring-biased plug 54 will be extended from the sleeve 53 (cf. FIG. l0) and prevents the next slat which has been passed by the stationary stop element 44 from passing beyond the first slat scanner 48. This stopping action is maintained until the end of the slat just moving alongside the second slat scanner 47 has reached a point past this scanner. Hereby the second slat scanner 47 is permitted in a return turning movement to revert to its initial position in which the roller intersects the slat path (FIG. 9). This return turning movement is transferred by connecting rod 49 to the first slat scanner 48 which is placed in a first position in which the sleeve 53 is laterally displaced and the plug 54 is in its extended position (FIG. 9). Due to this, the slat previously arrested by plug 54 (FIG. 10) is permitted to pass forwardly towards the second slat scanner whereby the cycle described above is repeated. In this way a forward feed of the slats one by one is obtained.

The guide pin 51 rigidly attached to the second slat scanner is provided with a follower p1n 51a (FIGS. l1 and l2) adapted to be in alternate sliding engagement with two surfaces of a lever 56 belonging to a switch 52, preferably of the microswitch type. The switch is adapted momentarily to close the circuit of the electromagnet 8 and thereby to trigger the upward movement of the slat lifter. One end of the lever 56j is connected to the break contact of the switch 52 whereas the other end thereof is deformed in an S-curve (FIG. l2). In this end there is provided a longitudinally extending aperture 57 having laterally extended end portions S8 which permit passage of follower pin 51a which during movement of guide pin 51 in one direction slides on the one surface of the lever through the extended aperture; when follower pin 51a arrives at one of the widened portions 58 it will pass through this portion and thereafter will abut against the opposite surface of the lever. This movement corresponds to the forward turning mover ment of the second slat scanner 47 which is transferred to the guide pin 51 via the rotatably journaled rod 55. When the return movement of the second scanner 47 takes place the follower pin 51a engages the other side of the lever. During this return movement the follower pin will depress lever 56 which now momentarily closes switch 52 during a short period of time, whereby the circuit of electromagnet 8 is closed and the magnet is energized. The excitation of the electromagnet 8 is terminated when the circuit is interrupted again, which will take place as soon as the follower pin 51a has reached depression on the S-shaped lever. The follower pin continues to engage the other side of the lever until the return movement has been terminated. Then the follower pin will pass through the second enlarged portion 58 of aperture 57 and will thereafter again engage the rst surface of the lever. Thus, the switch 52` will momentarily close the circuit of electromagnet 8 as soon as a slat has passed the second slat scanner 47 and the return turning movement of this scanner has started.

The short period of time during which the circuit is energized is controlled in part by the shape of the lever 56, the length of guide pin 51 and by the speed of the return turning movement; i.e., the force of the spring acting on the second slat scanner 47. The slats may be fed forward in the slat feeder 4 at an arbitrary speed which may be uniform or accelerated. The time interval between delivery of a slat from the slat feeder and the discharge of the following slat must be longer than or at least the same as, on the one hand, the time required for the rear transverse edge of a slat to pass through the horizontal distance from the outlet opening of the slat feeder to the starting position in the present apparatus in starting position which the lifting cord openings are positioned substantially above the cord ladder guides and, at the other hand, the time required for the slat carrier to perform the rising and descending movement. It should be noted that the rising movement of the slat carrier will not start immediately when the switch 52 transmits an impulse but rather is slightly delayed due to mechanical inertia of the electromagnet and other movable parts of the device. The time lag between transmission of an impulse from the switch 52 and the lifting of a slat by the slat carrier is sufficient to enable the rear end of the slat leaving the slat feeder to arrive at the starting position on the slat carrier.

In the drawings and specilcation there has been set forth a preferred embodiment of the invention and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

I claim:

1. Apparatus for mounting Venetian blind slats which, by means of a slat feeding device, are introduced through a slat path into aligned openings in cord ladders, said apparatus comprising an elongate frame, and slat mounting units carried by said frame and adapted for successively lifting individual slats and cord ladder sections from a starting position to an upper position in which the slats are collected in a slat storage space; characterized in that each slat mounting unit comprises a mounting plate having a recess therein, a slat carrier received in said recess in a position below the plane of the slat in the starting position, a slat lifter comprising a vertically reciprocatable rod operatively connected to said slat carrier and adapted successively to lift said slat carrier and individual slats and cord ladder sections from said starting position to said upper position, a guide pin carried by said rod, a cord ladder guide adjacent said mounting plate, and a variator guided and triggered by said guide pin and adapted to actuate said cord ladder guide alternately to place the cross cords of the cord ladder to respectively the one side and the other side of lifting cord openings provided in the slats.

2. An apparatus for mounting Venetian blind slats which, by means of a slat feeding device, are introduced through a slat path into aligned openings in cord ladders, said apparatus comprising an elongate frame, slat mounting units carried by said frame for successively lifting individual slats and cord ladder sections from a starting position to an upper position in which the slats are collected in a slat storing space; characterized in that each slat mounting unit comprises a slat lifter adapted successively to lift individual slats and cord ladder sections from the starting position in a straight path to the upper position, said slat lifter including a vertically reciprocatable rod and a guide pin carried by said rod, a cord ladder guide adjacent said slat lifter, a variator triggered by the slat lifter being adapted to actuate said cord ladder guide alternately to place the cross cord of the cord ladder to respectively the one and the other side of lifting cord openings provided in the slats, said variator comprising a support member rigidly mounted on the slat mounting unit and having a stud on which a variator plate is journaled, a guide plate journaled on a second stud provided on the lower part of the variator plate, said guide plate having two guide edges against which said guide pin is adapted to slide in alternation during reciprocating movement of said rod, a link arrangement provided on the variator plate and mechanically connected to said cord ladder guide and being adapted to adjust said cord ladder guide to a first position in which the cross cord of the cord ladder is positioned to one side of the lifting cord opening during alternate upward movements of said slat lifter rod, and said link arrangement adjusting said cord ladder guide to a second position in which the cross cord of the cord ladder is positioned to the other side of the lifting cord opening during the intervening upward movements of the slat lifter rod.

3. The apparatus as claimed in claim 2', characterized in that the guide edges of the guide plate include an acute angle at the upwardly directed tip of which there is provided an attachment pin extending through an arcuate opening in the variator plate, one end of a coil spring being attached to said attachment pin, and the other end of said coil spring being attached to said support member whereby the guide plate and the variator plate form a unit adapted to pivot about said pin between two stable equilibrium positions.

4. Apparatus for mounting Venetian blind slats which, by means of a slat feeding device, are introduced through a slat path into aligned openings in cord ladders, said apparatus comprising a frame, slat mounting units carried by said frame for successively lifting individual slats and cord ladder sections from a starting position to an upper position in which the slats are collected in a slat storing space, characterized in that each slat mounting unit comprises a slat lifter adapted successively to lift individual slats and cord ladder sections from the starting position in a straight path to the upper position, a cord ladder guide adjacent said slat lifter, and a variator triggered by the slat lifter being adapted to actuate said cord ladder guide alternately to place the cross cord of the cord ladder to respectively the one and the other side of lifting cord openings provided in the slats, said slat feeder comprising a plurality of aligned motor driven feed rollers for feeding slats from a rear zone to a forward zone, opposed pairs of pins being provided for guiding the slats as they are fed forwardly, characterized by a stationary stop element preventing more than one slat at a time from being fed to the forward zone, and an arrangement being provided for controlling the feeding space between respectively the rear and forward edges of successive slats to the forward zone and for momentary excitation of a switch in dependence on the release of a slat from the slat feeder.

5. The apparatus as claimed in claim 4, characterized in that said arrangement for controlling the feeding space comprises a lirst rotatably journaled slat scanner positioned behind the stop element and connected via a connecting rod and a guide pin to a second, spring biased, rotatably journaled slat scanner, positioned behind the first slat scanner and connected via a second guide pin to said switch.

6. The apparatus as claimed in claim 5, characterized in that said rst slat scanner comprises a rotatably journaled angular element having the form of a Z with two free ends one of which carries a sleeve or the like from which an outwardly spring-biased plug or the like extends, the other one of said free ends being pivotally connected to one end of said connecting rod, the other end of said connecting rod being connected to said second slat scanner to adjust said sleeve, on the one hand, in a first position with said plug fully extended and said sleeve laterally displaced permitting a slat to pass alongside said iirst slat scanner and, on the other hand, a second position with said plug in sliding contact with the passing Slat, said plug in said second position being partially pushed into said sleeve to be again fully extended from the sleeve after passage of said slat to intercept said Slat path while the sleeve still is in its second position, thereby to control the distance at which a following slat is fed forward in relation to the rear edge of the preceding slat.

7. The apparatus as claimed in claim 6, characterized in that said second slat scanner comprises a slat feeler or the like which is rigidly connected to a rotatably journaled rod or the like adapted to hold said feeler in a first position intercepting said slat path and provided with two rigid guide pins, one of which is pivotally connected with said connecting rod whereas the other one is in sliding contact with said switch, a slat passing said second slat scanner acting to displace with a forward turning movement said flat feeler to a second position while at the same time the slat feeler, by means of said one guide pin and said connecting rod, positions said first slat scanner into its second position with said plug in sliding contact with a slat, and a spring device operatively associated with said second slat scanner and operable in the absence of a slat to restore said feeler in a return turning movement to its first position while at the same time restoring said sleeve of said first slat scanner to its first position.

8. The apparatus as claimed in claim 4, characterized in that the guide pins are adjustable in pairs slidingly to receive between them slats of different widths.

9. The apparatus as claimed in claim 4, characterized in that said switch is provided with a lever, one end of which is firmly connected to said switch, whereas the other end of said lever is slightly S-curved and provided with a substantially elongate hole having enlarged end portions permitting passage of a follower pin provided on the free end of said guide pin, said follower pin being in sliding contact during the forward turning movement of said second slat scanner with one surface of said lever while being in sliding contact with the other surface of said lever during the return movement of said rod to close said switch for a certain period of time, an electromagnet operatively connected to said slat lifter for raising the same from said starting position to said upper position upon energization of said electromagnet, and said switch being connected to said electromag'net for momentarily energizing said electromagnet simultaneously with the discharge of a slat from said slat feeder.

References Cited UNITED STATES PATENTS 2,827,686 3/ 1958 Adelman 29-24.5 2,893,106 7/ 1959 Rosenbaum 29--245 2,917,810 12/1959 Wilson 29-24.5 3,292,232 12/ 1966 Nilsson 29-24.5

FRANK T. YOST, Primary Examiner