US2970704A

US2970704A - Discharging assembly for kiln loads of lumber

Info

Publication number: US2970704A
Application number: US766449A
Authority: US
Inventors: Arthur H Beckley
Original assignee: Moore Dry Kiln Co
Current assignee: Moore Dry Kiln Co
Priority date: 1958-10-10
Filing date: 1958-10-10
Publication date: 1961-02-07
Anticipated expiration: 1978-02-07

Description

DISCHARGING ASSEMBLY FOR KILN LOADS 0F LUMBER Filed 001;. 10, 1958 A. H. BECKLEY Feb. 7, 1961 4 Sheets-Sheet 1 INVENTOR. ARTH U R H.

BECKLEY ATTORNEY Feb. 7, 1961 A. HJBECKLEY 5 3 DISCHARGING ASSEMBLY FOR KILN LOADS OF LUMBER Filed Oct. 1 0. 1958 4 Sheets-Sheet 2 I" "m r n H \T 24 INVENTOR. ARTHUR H. BECKLEY ATTO RN EY Feb. 7, 1961 A. H.'BECKLEY 2,970,704

DISCHARGING ASSEMBLY FOR KILN LOADS 0F LUMBER Filed Oct. 10, 1958 I 4 Sheer .s-Sheet 3 .ATORN EY Feb. 7, 1961 A. H. BECKLEY 2,970,704

DISCHARGING ASSEMBLY FOR KILN LOADS 0F LUMBER Filed Oct. 10, 1958 4 Sheets-Sheet 4 INVENTOR. ARTHUR H. BECKLEY ATTORNEY United States Patent DISCHARGING ASSEMBLY FOR KlLN LOADS 0F LUMBER Arthur H. Beckley, Portland, Greg, assignor to Moore Filed Get. 10, 1958, Ser. No. 766,449

3 Claims. (Cl. 214-85) This invention relates to the discharging of lumber loads as they are moved out of a lumber drying kiln, such discharging including the unstacking or the removal of the pieces of lumber from the stacks in which the pieces of lumber are arranged on truck assemblies for drying in the kiln.

The regular procedure in the discharging of lumber loads is for the operator to move each load or stack of lumber, as it leaves the kiln, onto an unstacker lift. Then, when the stack or load is properly positioned on the lift, the operator causes the lift to move upward gradually while mechanical means, well known in the industry, push the pieces of lumber off of the successive layers in the stack, as each layer in turn becomes the top layer and is positioned at the proper level for having the pieces of lumber pushed off. In carrying out this procedure it has generally been customary for the operator to attach a cable from a small winch or car puller to each kiln load or lumber stack and to pull the load on its supporting truck assemblies onto the unstacker lift. Since it is necessary to get the load exactly in proper position on the lift for the removal of the successive layers of pieces of lumber, the final positioning of the load on the lift is usually done by the operator with the aid of an ordinary pry bar. When this is completed the operator ascends to his station or platform adjacent the top of the lift load and operates the controls for the lift and for the unloading means.

This customary procedure, as is well known, is both time consuming and fatiguing to the operator, for it requires the operator to descend from his platform station, to walk to the load which has been discharged from the kiln, to attach the winch cable to the load, to return to the winch in order to pull the load onto the lift, then to detach the cable from the load and complete the posi tioning of the load on the lift, and finally to return to his platform station and operate the controls for the lift and for the lumber removing means.-

The object of the present invention is to provide improved and practical means for moving the load onto the lift and then for properly positioning the load on the lift, with such means so constructed and arranged that it can be operated and controlled from the operators position on his platform station, thus dispensing with the necessity of having the operator leave his platform station during the carrying out of the unloading procedure and consequently enabling the operator to save both time and labor.

A related object of the invention is to provide equipment with adequate automatic controls to prevent any inadvertent or undesired moving of the lumber load and to prevent any possibility of damage to such equipment as a result of carelessness or failure of any part of the device to function properly.

The means by which these objects and other advantages are achieved, and the manner in which the improved means is constructed and arranged, and the manner in .which the different parts of the entire. assembly function,

EQQ

will be briefly described and explained with reference to the accompanying drawings.

In the drawings:

Fig. 1 is a foreshortened side elevation showing a lumber load in the process of being moved towards the unstacker lift by a load pusher or charger and showing the lift in partly raised position for the unstacking of a lumber load previously positioned on the lift;

Fig. 2 is a corresponding plan view, but with the lumber loads omitted for the sake of clarity and their positions indicated only by broken lines;

Fig. 3 is a fragmentary sectional elevation taken on the line indicated at 3-3 in Fig. 2, drawn to a larger scale, and also showing the end of the lumber load engaged by the load pusher or charger;

Fig. 4 is a corresponding side elevation of the load pusher or charger, drawn to the same scale as Fig. 3, but with the load pusher and the load itself shown moved further to the left so that the load is positioned on the lift;

Fig. 5 is a fragmentary section, drawn to the same scale as Figs. 3 and 4 and taken on the lines indicated at 5-5 in Fig. 2;

Fig. 6 is a fragmentary enlarged sectional elevation of the load positioning means located on the lift, this section being taken on the line indicated at 66 in Fig. 2; I i

Fig. 7 is a fragmentary sectiontaken on line 7-7 of Fig. 6 and drawn to a larger scale; and V Fig. 8 is a wiring diagram.

Referring first to Figs. 1 and 2, the load or stack of lumber which is being moved out from the kiln is indicated at it) and is supported, as usual, on a plurality of truck assemblies indicated by the reference character 11 in Fig. 1. These truck assemblies ride on a pair of

rails

12 and 13 leading into and out from the drying kiln. A similar pair of rails 12' and 13' (Fig. 2) are provided on p the lift 14, and, when the lift is in the lower or loading position, the rails 12' and 13 on the lift are in registration with the

rails

12 and 13.

For the purpose of moving each lumber. load or stack along on the

rails

12 and 13 from the kiln and onto the lift 14 a special pusher or charger, indicated in general by the reference character 15, is employed, and is manipulated through suitable switch controls by'the operator from his platform station. This pusher 15 rides on a pair of T-bars 16 and 17 (Figs. 2 and 5), being held on the bars by pairs of upper and lower wheels 18 and 19 (Figs. 3 and 5), and this pusher is connected to a pair of

endless sprocket chains

20 and 21 which are driven in unison. At the end of their course near the elevator 14 these

sprocket chains

20 and 21 pass around a pair of driven

sprockets

22 and 23 secured on a shaft 24 which is driven by suitable connection from areversible motor. 25. At the other end of their course these sprocket chains pass around idler sprockets (not shown) located near the drying kiln.

The pusher 15 includes a main frame 26 having a topdeck (Fig. 5) and downwardly-extending side plates on each side, on which side plates the stub shafts for the

wheels

18 and 19 are mounted. A transversely-extending shaft 27 extends across the-main frame 26 close to the top deck and near the front end of the pusher (Figs. 3 and 5). A rod 28 has one end mounted on the central portion of the shaft 27 and the other end of this rod is mounted on a transverse shaft 29 the ends of which are secured to the two

sprocket chains

20 and 21. Through this arrangement the rotation of the drive shaft 24 (Fig.

' 2) in one direction by the motor 25 causes the pusher 15 Patented Feb. 7, 1961 and located on the outside of the mainframe of the pusher 15. An integral, downwardly-extending bracket 30' is connected to each of the arms 38 and the lower end of each of these brackets 30 is pivotally connected to a slide rod 32 (as shown best in Fig. 4) which is slidable in a bracket 33 secured on the corresponding side of the main frame of the pusher 15. A coil spring 34 iscarried on each slide rod' 32 and is held. under compressiorr between the bracket 33 and a collar 35 adjustably mounted on the slide rod. A nut 36 on the rear end of each slide rod 32 limits the forward movement of the slide rod and thus limits the upward swing of the arms 33 under the force of the springs 34. As apparent from Fig. 4, the slide rods 32 hold the arms 36' normally in forwardly -upwardly-extending position but enable these arms 30 to be pushed downwardly to a limited extent against the force of the springs 34. A' load-engaging crossbar 31 is carried on the forward ends of the arms 31).

The top deck of the main frame 26 of the pusher 15 is low enough so that it will pass freely beneath the truck assemblies 11 on which the lumber stacks are carried, but the crossbar 31 carried by the extending arms 3% will engage the transverse frame members 11' of the truck assemblies 11 when the arms 30 are in the normal raised position indicated in Figs. 1 to inclusive. When a stack of lumber from the kiln is readyto be moved onto the lift 14 the pusher 15 is moved from left to right, as viewed in the figures, passing beneath the truck assemblies on which the stack of lumber is carried until the pusher is positioned behind the load (thus to the right of the load). The spring mounting for the arms 30 allows them to be thrust downwardly by engagement with the bottom transverse frame members 11' of the truck assemblies 11 as the pusher is moved beneath the load (towards the right) until the pusher is clear of the load, whereupon the arms and load-engaging crossbar 31 return to normal position for engaging the rear, or right-hand end, of the load and truck assemblies. Then the movement of the pusher towards the left causes the load to be moved towards the lift 14.

The motor 25 (Fig. 2) for moving the pusher 15 is driven in either direction by switches controlled by the operator from his station platform,enabling the operator to move'the pusher 15 in either direction as desired with out descending from his station platform. Limit switches are provided to prevent inadvertent travel of the pusher too far in either direction. A switch-engaging bar 37 (Fig. 4) i'smounted on one of the side plates of the main frameof the pusher 15'. A pair of limit switches A and B, having spring-controlled actuating arms, are so positioned as to be. engaged by the bar 37 as the pusher approaches near the lift 14. The first switch A will be engaged by the bar 37 when the forward. end of the arms 30 of the pusher are within a slight distance of the lift 14-. Should the lift be in raised position at that moment the actuation of the switch A, as later described, Will stop the travel of the pusher to the left at this point and thus prevent the arms 30 from extending into the path of the descending lift. However, if the lift is inlowered starting position, as shown in Fig. 4, the switch A will then be ineffective for limiting the travel of. the pusher and the pusher cancontinue to move towards the lift until switch B-isengagedt by the bar37. A limit switch (indicated diagrammatically at F in the wiring diagram of Fig. 8.) limitsvthe' travel of the: pusher in the opposite direction or to the right.

In order to prevent a lumber load from being moved too far towards the lift 14 when the lift is not in lowered position, and thus when the lift is not in position for receivingsuch load, an additional limit switch C (Fig; 2)

load as long as the lift remains in raised position. However this switch C becomes inefiective for stopping the motor 25 when the lift is in lowered position.

The operation of the switch controls, as mentioned thus far, will be understood from a brief description with reference to the wiring diagram in Fig. 8. In Fig. 8 L1 and L2 indicate two main conductors from a suitable source of electric power. The reversible motor by which the lift 14 is moved up or down is indicated at 54) and the control switch for this motor (which is located on the platform station of the operator) is indicated at 56A. The reversble motor 25, which drives the sprocket chains which move the pusher 15' is controlled by the switch 25A (also located at the operators platform station). A and B are switches which are opened when contacted by the pusher 15. C is the switch which is opened when contacted by the lumber load. D and E are switches which are closed by the lift 14 when the lift is in lowered or loading posithan. F is the switch which is opened when contacted by the pusher 15 and limitsthe travel of the pusher to the right. The following examples illustrate the different operating conditions.

Case 1:-When the lift 14 is in lowered or loading position, it is desired to have the pusher 15 move from right to left to push a load onto the lift. The switch 25A is therefore moved to connect contacts 51 and 52. Current from conductor L1 passes through line 53, contacts 51 and 52, line 54, closed switch C, line 55, line 56, closed switches A and B, and line 57 to motor 25. The motor 25 is' connected tothe other main conductor L2 by the line 58'. As the load is moved towards the lift the load opens switch- C. However, since switch E is closed, the current will pass to line 55 through switch E and the motor 25 will continue to operate. (If the lift 14 were in raised-position, and thus with switch E open, the opening of switch C by the load would then prevent further travel of the load until the lift is in lowered or loading position.) As the pusher and load continue to move to the left the pusher comes into engagement with switch A causing this switch to be opened. Current through line 55 passes through line 59, closed switch D, line 69, closed switch B and line 57 to motor 25. When the pusher moves further to the right it opens switch B. The opening of switch B prevents any further travel of the pusher to the left under any conditions.

' Case 2:--When the pusher is in the extreme ieft position, after having pushed the load onto the lift 14, the operator should then move the pusher back to the right. He does this by moving switch 25A to connect contacts 61 and 62. Current then passes from line 53 through line 63; closed switch F, line 64, contacts 62 and 61, and line 65 tomotor 25, causing the motor to operate in reverse direction until switch F is opened.

Case 3:-When the load has been moved onto the lift 14- the operator, in order to cause the lift to be raised, moves the control switch50A for the lift motor 50 so as to connect the contacts 66 and 67. Current from main conductor L2 passes through line 68, contacts 67 and 66, line 69 to motor 50; and current from the main conductor L1 passes through line 70, closed. double switch B, and line, 71 tomotor 50. However, if the, operator has neglected to move the pusher 15 to the right sufficiently to be out of the path of the lift 14, in other. words, if the double switch B is still engaged, by the pusher, the circuit to the lift motor cannot be closed through line 71 and the lift cannot be raised.

Case, 4:-When. the lift 14 is in raised position and is to be lowered toloading position the operator moves to the right out of the path of the lift, the lift cannot be lowered. Thus any damage to the pusher by careless lowering of the lift is prevented.

The lumber stack must be accurately positioned before the upward movement of the lift is started in order that the pieces of lumber in the successive top layers of the stack may be pushed off from the stack as the lift, with the stack thereon, is gradually raised.

When the pieces of lumber are arranged in the stack on the supporting truck assemblies for drying in the kiln, lumber pieces generically will not all be the same length and it is customary to arrange the stack so that the ends of the pieces will be even with each other at one end of the stack. If this even or aligned. end of the stack always constituted the end engaged by the pusher in moving the load onto the lift the pusher would be capable of positioning the load accurately on the lift. However, frequently the even end of the stacked load will be the end away from the pusher, in which case it is necessary to have further means for accurately positioning the load on the lift. Such lift load positioning means, which forms an additional important feature of the present invention, will now be described with reference to Figs. 1, 2, 6 and 7.

An endless sprocket chain 38 (Fig. 6) passes over a driven sprocket 39 at one end of its course and over an idler sprocket 40 at the other end of its course. The shafts for these sprockets are carried in suitable bearings mounted on the lift 14. The shaft in which the driven sprocket 39 is secured carries a drive sprocket which in turn is driven by suitable connection with the reversible motor 41 supported on the bottom of the lift. Details of the lift need not be described since the lift, except for this special load positioning means on the lift, is of the type commonly employed in lumber yards for unstacking lumber loads after drying. Up and down movement of the lift is produced by a reversible motor, indicated diagrammatically at 50 in Fig. 8, as previously described, with the control switch for the same located on the operators platform station.

The upper course of the sprocket chain 38 (Figs. 6 and 7) rides on a supporting channel-shaped guideway 42 carried on a platform 43. This platform 43 is resiliently mounted on a plurality of 'posts 44 which are slidable up and down to a limited extent in guiding apertures provided in the fioor of the lift. Coil springs 45 on the slidable posts 44 exert a force to keep the platform 43, and therewith the guideway 42 and upper course of the sprocket chain 38, in the maximum raised position permitted by the nuts 46 on the bottom ends of the posts 44. The platform 43 has downwardly-extending side ears 43' on both sides which slide on the outer faces of brackets 47, and stationary guide pins 48, secured on the stationary brackets 47, extend through vertical slots in the ears 43' and hold the platform 43 against longitudinal movement with respect to the stationary brackets 47.

In the normal raised position of the platform 43 the upper course of the sprocket chain 38 will be high enough to be engaged by the bottom transverse members 11 of the truck assemblies on which the lumber stack is supported. In other words, when a lumber load is pushed onto the lift by the pusher 15 the transverse support members 11 at the forward end of the load will be pushed into engagement with the sprocket chain 38 and cause the engaged portion of the sprocket chain and the guideway 42 and supporting platform 43 to be depressed to some extent against the force of the springs 45. Under such circumstances if the motor 41 is operated so as to cause the upper course of the chain to move towards the left (as viewed in Fig. 6 and also in Figs. 1 and 2), the load will then be moved to the left on the lift to the distance desired. The motor 41 is controlled by the operator from his position on his platform station by meansof a switch which is indicated at 41A in the wiring diagram of Fig. 8. Preferably this switch is in the nature of a jog switch. In this way the operator, from his platform station adjacent the top of the stack on the lift, can move the load into proper position on the lift for having successive layers of boards pushed off from the stack as the lift is gradually raised. Finally, when the load has been completely unstacked by the removal of all of the pieces of lumber, the operator can discharge the empty truck assemblies from the lift platform by stopping the lift at the proper discharge position and causing the engaging chain 38 to move the truck assemblies off from the lift and onto the return track for the empty truck assemblies.

Thus the present invention enables the operator, without descending from his platform station, to move each stack of lumber, as delivered from the kiln, onto the unstacker lift merely by the operation of control switches. The safety switches prevent any inadvertent movement of the lumber stack or pusher into the path of the lift when the lift is not in the lowered position for receiving the load from the pusher. The operator, with the use of the further, conveniently located switch for the motor 41 can cause the load to be set in desired position on the lift for unstacking, regardless of which end of the load is the even end. By causing the lift to move upwardly gradually as each successive layer of boards is removed from the stack, in the customary manner, the unstacking of the load takes place. Finally the operator causes the empty truck assemblies to be discharged from the lift and returned for reloading of another stack to be dried. All this is done by the operator merely by the manipulation of control switches and without requiring the operator to leave his platform station adjacent the top of the lift.

I claim:

1. In a lumber discharging assembly of the character described having an unstacker lift and lumber load-carrying trucks mounted on guide rails and movable onto and off of said lift, a load pusher for pushing lumber loads onto said lift, said pusher movable beneath the load-carrying trucks when moving in a direction away from said lift, spring-controlled engaging means mounted on and extending forwardly and upwardly from said pusher for engaging a load in front of said pusher when said pusher is moving towards said lift, electricallyoperated means for moving said pusher towards or away from said lift, a control circuit for actuating said electrically-operated means, a rear limit switch in said circuit limiting the travel of said pusher when said pusher is moving away from said lift, aforward limit switch in said control circuit operated by said pusher limiting the maximum travel of said pusher towards said lift, a lift-operating motor, a control circuit for said lift-operating motor, a make andbreak in said latter mentioned circuit operated by said forward limit switch, whereby movement of said lift will be prevented when said forward limit switch is engaged by said pusher, and load-positioning means on said lift, said load-positioning means including an endless chain arranged in a substantially vertical plane, the upper course of said chain riding on a spring-supported guideway and adapted to be engaged by a loadcarrying truck when the truck is pushed onto said lift, a reversible motor on said lift for operating said chain, and a remote control switch for said latter mentioned motor.

2. The combination set forth in claim 1 with the addition of an intermediate limit switch in said first men tioned control circuit arranged to be operated by the forward end of a load when said load is being moved towards said lift, whereby to halt movement of the load when said lift is not in lowered position, and a by-pass switch for said intermediate switch in said first mentioned. control. circuit closed by said lift when said lift is in lowered position.

3. The combination set forthin claim 1 with the addition of an intermediate limit switch in said first mentioned controlcircuit arranged to be operated by the forward end of a load when said load is'being moved towards said lift, whereby to halt movement of the load when said lift is not in lowered position, a by-pass switch for saidlintermediate switch in said first mentioned control circuit closed by said lift when said lift is in lowered position, a second intermediate switch in said first mentioned control circuit operated by said pusher when said pusher is moving towards said lift, whereby to stop the forward. movement of said pusher unless said lift is in lowered position, and a. by-pass switch for said second intermediate switch when said lift is in lowered position.

References Cited in the file of this patent 7 UNITED STATES PATENTS Eisenberg Sept. 22,. Lamb June 25, Minaker et a1 Dec. 28, Miller Nov. 25, Zeckendorf et al Mar. 22, Perry et al. Nov. 19', Bardsley et al. Apr. 1, Merritt Aug. 19,

FOREIGN PATENTS Great Britain Mar. 21,.