US2756885A

US2756885A - Die handling industrial lift truck

Info

Publication number: US2756885A
Application number: US436210A
Authority: US
Inventors: Joseph A Ackermann
Original assignee: Elwell Parker Electric Co
Current assignee: Elwell Parker Electric Co
Priority date: 1954-06-11
Filing date: 1954-06-11
Publication date: 1956-07-31
Anticipated expiration: 1973-07-31

Description

Juiy 31, 1956 J. A. ACKERMANN DIE HANDLING INDUSTRIAL LIFT TRUCK 3 Sheets-Sheet 1 Filed June 11. 1954 INVEN TOR. .1056?! A. ACA'E/IA/V/V Arroew'ys 3 Sheets-Sheet 2 57 19% J. A. ACKERMANN DIE HANDLING INDUSTRIAL LIFT TRUCK Filed June 11, 1954 Y 31, 1955 J. A. ACKERMANN 2,756,885

DIE HANDLING INDUSTRIAL LIFT TRUCK Filed June 11. 1954 :s Sheets-Sheet 5 INVENTOR. JOJTPH ,4. ACXFIPM/M IV hired States Patent to The Elwell Parker Electric Company, Cleveland,

Ohio, a corporation of Ohio Appiication June 11, 1954, Serial No. 436,210

Claims. (Cl. 214514) are used in forging and sheet metal forming operations, 1

frequent changing of the dies is often desirable and the time consumed in the change is an important cost factor since the heavy investment in such presses requires that they be maintained in production operations. The dies used in such presses frequently weigh several tons and heretofore the us of industrial trucks equipped with die tackling means have been proposed for removing, storing and replacing the dies. Space restrictions on truck maneuvering about the press has been a hindering factor heretofore and the general object of the present invention is the provision of means on a heavy-duty industrial truck which can be presented to the die load and engage it to effect extraction of the die equipment from the press in an expeditious manner and which will also serve to position the die equipment in the press when changes are desired.

To this end a heavy duty tier lift truck of the platform type is provided with a dual hydraulically operated load engaging means which is effective in manipulating a die set on the bed of the press during die set up operations and which will be effective in removing and replacing die sets in presses of the aforementioned type.

A more specific object is the provision of a die handling means on an industrial truck which will be of sufiicient ruggedness as to handle safely die sets of relatively heavy weight and store the same.

A more specific object of the present invention is the provision of a multiple force applying mechanism on the platform structure of a tier lift truck which will serve to apply pushing and pulling forces to the load simultaneously or selectively thereby to maneuver the load as desired.

Other objects of the invention hereinafter will become apparent to those skilled in the art from the following description referring to the accompanying drawings which illustrate a preferred form thereof. The essential characteristics of the invention are summarized in the appended claims.

In the drawings:

Fig. 1 is a partial side viewshowing the pertinent parts of a truck embodying this invention, certain parts being removed or broken away to show the structure more clearly;

Fig. 2 is a perspective side view of the truck with the elevator carriage in a raised position and the die manipulating mechanism in position for use of the pusher arms; and

Fig. 3 is a view in perspective from a in front of the truck.

The truck of this invention as shown in the drawings is comprised of a dirigible automotive vehicle chassis V, a hydraulically operated elevator mechanism E includpoint above and 2,756,885 Patented July 31, 1956 or pushed ofi the platform, and along each side of the platform a double acting hydraulically operated motion multiplying mechanism H for moving the opposite sides of P independently.

Two longitudinal beam members 10, converging to a narrow front portion 10a and joined by suitable cross members provide a vehicle frame supported at the rear by the driving wheels 11 andat the front along the narrowed portion 10a by two pairs of double wheels 12 mounted together in such fashion as to form a power steering assembly with the wheels adapted to accommodate to unevenness of the truck supporting surface. The

steering assembly is not here described in. detail since per so no part of this invention. A pair of parallel heavy upright column members 13 are welded to the outside of the long frame members 10 to provide the uprights of the elevator mechanism supporting the carriage C in vertically removable relation. At the rear of the vehicle above and overhanging the driving wheels suitable structure is provided on "the frame for support of the truck driving and operating mechanism, such as batteries, motors and controls for an electric truck, an operators station, not further detailed since standard vehicle struc- :ture and equipment, and certain controls and various hydraulic pump equipment hereinafter described.

In the carriage, a transverse vertical plate 15 serves as a base to the rear face of which are welded two like pairs of spaced plates 16 and 17, outer and inner plates respectively, extending vertically and rearwardly along opposite sides of each upright column 13, while if desired, a reinforcing gusset 18 may be welded at an angle between the outer plate 16 and the baseplate. To form a die supporting platform, a horizontal bed plate 20 is welded at itsback edge tothe transverse base plate 15 and along lateral edges to the top edges of forward ex tensions 16a of the lower part of the plates 16 which form side skirts of the platform, while a fore skirt plate 21 Welded to the forward edges of the horizontal and skirt plates has each end portion reflected rearwardly in outwardly spaced relation to the side skirts 16a to form a housing and bracket support 21a for sprocket 22. The carriage is movably supported on the uprights by roller wheels 24, journalled on short shafts between the plates 16 and 17 near the top of the carriage to roll on the back face ;of the uprights 1'3, and by lower wheels 25 rolling on the forward face of uprights, each journalled on a corresponding shaft between theside skirts 16a and a bracket plate depending from the bottom of the bed plate 20. Those portions of :the'uprights traversed by the carriage wheels may be provided with hardened bearing strips 13a, 13b. If desired, auxiliary guide means in the form of rollers orperhaps simple studs may-be provided projecting from the outer plate 16 inwardly within the lateral shallow channels of the columns to engage one of the channel surfaces.

A pair of single-acting hydraulic piston and cylinder elevator lift units 27 betweenthe elevator uprights 13,

with lower convex cylinder ends bearing upon the horizontal member 28 of the frame to take the thrust of liftlow the limit of travel of the upper wheels 24. At the lower end-of each cylinder, bolts 35 are passed through diametricallydisposed cylinder lugs 36 and threaded into the horizontal frame member 28 to maintain the lateral spacing of the cylinders without however absorbing any of the lifting forces. With the reaving system here provided a two to one motion ratio is provided between the movement of the carriage and that of the pistons.

To power the hydraulic lifting cylinder units, there is located on the truck frame a hydraulic oil reservoir, a motor driven pump delivering oil from the reservoir to the cylinders, and suitable control elements controlling the pump motor operation and flow of fluid from the pump to the cylinders in elevator lifting and from the cylinders back to the reservoir in lowering the elevator. However, for purposes hereinafter described, it is preferable that two pumps driven by a common motor be provided with a lift cylinder control including an oil valve which puts the pump outlets in parallel relation to provide a single common source of hydraulic fluid to both cylinders in elevator lifting and for directing the fluid to the reservoir for lowering the same. A common manual control lever is mechanically interlinked with both a motor control switch for the electric pump motor and lift cylinder oil valve means in such manner that with the control lever at lift position, the pump motor is on and the oil valve connects the pumps in parallel relation to supply oil to the cylinders; at hold position, the motor is off and flow of hydraulic fluid relative to the cylinders blocked; and at lowering position the motor is off with the hydraulic line to the lift cylinders opened to the fluid reservoir to exhaust fluid from the cylinders and permit the carriage to descend by gravity.

The die manipulating mechanism P comprises a pair of stanchions 4th on carriages 41 independently moveable in track assemblies 42 along each side of the bed or platform, cable anchor elements on the stanchions and a pair of die pusher arms 43 carried by an extensible support in the form of

telescoping cylinder members

45, 46 with opposite end lugs 47 pivoting on the upper parts of the stanchions. The anchor elements may be removeable eye pins 48 dropped into bores of the stanchions. Each arm 43 is mounted on the outer cylinder 46 by a sleeve portion 43a permitting the arms to be swung to an upright position from their normal forwarding extending horizontal disposition, used in pushing a die or other load from the bed. A rib 49 running partway-out from the sleeve along the arm, in coming to bear on the surface of bed 20 serves as a stop maintaining the arm in horizontal position, while a lock pin 50, slideably mounted on the arm and spring biased inwardly to project radially through the sleeve for detent engagement with apertures in the outer cylinder 46, holds the arm in selected position. Load contact pads 51 pivotably secured on the free ends of the arms are self-adjusting to the disposition of the load surface against which the arms hear.

The hydraulically powered mechanisms H provided for each stanchion aflord means for moving the opposite ends of the manipulating device P independently. In each mechanism H, the carriage 41 is on each side supported by a pair of roller wheels 54 running in tracks formed between the flanges of opposed inner and

outer channel members

55, 56, extending along the top portion of the corresponding side skirt 16a of the carriage platform and spaced to provide a slot between the upper channel flanges through which the carriage stanchion 40 extends. The channels are secured to the skirt 16a, the inner channel 55 directly and the outer channel 56 through an angle member as a bracket with one side underlying both channels.

The channels extend from the housing 21a of the fixed forward sprocket 22 back beneath the outer edge of plate toward a bracket plate 58, spaced outwardly from the lower back area of side plate 16 by side flanges welded thereto to form a housing for

sprockets

59, 60 journalled on vertically spaced shafts between bracket 58 and carriage side plate 16.

A double acting hydraulic piston and cylinder unit, mounted with the cylinder anchor lug 61 held by a pin 62 between plate 16 and bracket 58 and with the working end of the cylinder 63 held to side skirt 16a by a U-shaped clamp bolt 64, includes a piston crosshead 66 on the piston rod supported in its working stroke by a roller 67 running on a flange or plate 68, along the bottom of the side skirt. Between the two spaced vertical plates forming the piston crosshead are mounted the support roller 67, the end of the piston rod, the single sprocket roller 69 near the forward end of the crosshead and in line with the piston axis, and the pair of sprocket rollers 70, 71 spaced on either side of the piston axis inward of the support roller. The chain 73 with one end anchored at the front of the carriage 41 and passing around the forward fixed sprocket 22 and the forward sprocket 69 of the crosshead with its other end anchored to the fore skirt; and the chain 74 with one end anchored to the back of the carriage 41 and passing around the fixed rear sprockets 59, 6t and the rear sprockets 70, 71 of the crosshead with the other end anchored to the anchor bracket 77 on the side skirt, constitute two to one motion multiplying connections by which the forces of the unit are applied to the carriage 41 for pushing a load from or drawing it upon the bed. Hydraulic fluid under pressure is of course supplied to forward cylinder port 78 to drive the crosshead 66 back in advancing the device and thereby expelling fluid from rear port 79; and to the rear port 79 in retracting P.

Preferably individual hydraulic pumps supply hydraulic fluid pressure through individual oil reversing control valves to the cylinder units, the two controlled outlet ports of each valve being connected to lines 78 and 79 of a corresponding cylinder, so that the two carriages may be moved independently, or may apply different 1 forces to a load, whereby more flexible load manipulation may be had without shifting the vehicle. An independent hydraulic pressure system may be used for the pusher actuating cylinders; but to the same end, the previously described hydraulic power system of the elevator, namely the motor, two pumps and reservoir may be used with suitable cooperating controls, since there is little or no need simultaneously to lift and horizontal ly shift a load. The two pumps of the lift system driven by the single motor act in tandem in supplying the double acting cylinder units, each supplying oil to one of the units through a control valve adapted to direct oil selectively to either end port of the unit, while releasing oil from the other port to the reservoir, or to block oil flow altogether for locking a carriage at particular position.

For such control system, each unit would require an oil reversing valve with a valve inlet connected to the outlet of one of the pumps, an exhaust port connected to the oil reservoir, and two controlled ports connected to the opposite ends of the cylinder, so that by movement of a valve piston member from neutral position (where oil to and from the cylinder through the valve is blocked locking the cylinder), to one or the other of two operating positions, oil is directed to one or the other end of the cylinder, While the other end is exhausted to the reservoir. Manual control means for each of these valves is me chanically or otherwise linked to a control switch for the electric pump motor, so that when either of the controls is moved to a cylinder operating position, the pump motor is turned on. To use these same two pumps acting in parallel to supply oil to a common line branching to the two lift cylinders 27, additional lift control valves may be inserted in the lines between a pump and corresponding reversing valve. Each of these lift control valves has a controlled outlet port connected to the common feed line to the lift cylinders, an exhaust outlet for returning the oil from the lift cylinders to the reservoir, an oil inlet connected to the corresponding pump, and a valve piston element which at neutral position blocks flow relative to the cylinders, at elevator lowering position connects the cylinder ports to the valve exhaust port, and

at lift position directs fluid from the pump inlet ports through the valve outlet ports to the common feed line. A single manual control element for the lift cylinders is mechanically linked to such lift control valves and to a switch for the pump motor to connect the pumps in parallel when the motor is turned on for elevator lifting by shifting the valve elements to direct fluid to the common cylinder feed line.

The operation of this truck will be described in terms of heavy dies inserted or removed from the die bed of a press with transportation to or from a die storage area.

The truck is maneuvered into suitable position adjacent endwise to a die to be removed from a press bed or storage location, and the carriage is raised if necessary to the level of the die. The manipulating device P with arms upright is run forward to the end of the platform and the die is secured thereto by steel cable or the like secured to the anchor elements of the stanchions and to anchor formations on the die, or simply passed around the die. The manipulating device is then retracted drawing the load onto the bed or platform of the carriage,

the two stanchions being moved, if required for the desired disposition of the die on the carriage, with a differential movement through the independent controls of their hydraulic power mechanisms. In Fig. 1 the truck is shown in the process of drawing a die D onto the carriage through cables L secured to the anchor eyes of the stanchions.

After the truck is run, with carriage lowered, to the point for unloading, say a press bed, the truck is directed into a position whence the die may be pushed off endwise of the carriage into the press bed, the carriage height being adjusted as required. The manipulating device P is advanced to push the load from the platform into the press bed. Where the additional reach of the pusher arms beyond the end of the carriage is not needed, this may be done with the arms in upright position. If the projecting length of the arms is needed and the carriage platform area occupied by the die permits the arms to be dropped, the arms may be used for the whole push-off strike; otherwise, after an initial advancement of the die on the platform to give clearance for dropping the arms to horizontal position, the device P is retracted, the pusher arms released and dropped into horizontal position, and the device P again advanced to move the die through the arms. Since the manipulating device is thus in contact with the die after the die is off the carriage bed, the die may be squared away or moved within certain limits to some particular orientation in the press by the differential movement afforded by the independent control of the two carriages. Of course in such loading and unloading operations, the frictional forces developed between the load and a surface external to the truck may require that the truck brakes be applied to keep the vehicle from shifting.

I claim:

1. In an industrial truck of the lifting platform type, a movable stanchion disposed at each side of the platform structure of the truck to extend from below to above the load supporting surface of the truck, stanchion carrier means disposed below the platform load supporting surface for supporting each stanchion, a guiding trackway structure for each carrier means, hydraulically operated means disposed parallel to each trackway, motion multiplying means connecting the hydraulically operated means to the stanchion carrier means, load engaging means connected to the stanchions, a source of hydraulic power on the truck and controller means for selectively connecting the hydraulically operated means and the source of hydraulic power whereby the stanchion carriers may be selectively moved.

2. In an industrial truck of the lifting platform type, a moveable. stanchion disposed at each side of the platform structure of the truck to extend from below to above the load supporting surface of the truck, stanchion carrier means disposed below the platform load supporting surface for supporting each stanchion, a load engaging telescopic means connecting the stanchions, a guiding trackway structure for each carrier means, a hydraulic ram disposed parallel to each trackway, a crosshead for each ram, a trackway for the crosshead and motion multiplying means connecting the hydraulic means to the stanchion carrier means.

3. An industrial truck of the lifting platform type having a load moving stanchion disposed to operate at each side of the truck platform to push or pull a load from or to the load supporting surface of the platform in a direction longitudinally of the truck, load engaging means yieldingly connecting the two stanchions, stanchion carrier means for each stanchion mounted on trackways on the platform disposed below the load supporting surface of the platform, a double acting hydraulic ram for operating each carrier means including a motion multiplying means connecting each ram to its carrier and load pushing arms pivotally connected to the stanchion connecting means.

4. An industrial truck of the lifting platform type having a load moving stanchion disposed to operate at each side of the truck platform to push or pull a load from or 'to the load supporting surface of the platform in a direc* tion longitudinally of the truck, yieldable means connecting the stanchions above the platform, stanchion carrier means for each stanchion mounted on trackways on the platform structure disposed below the load supporting surface of the platform, and a power means for operating each carrier means.

5. In an industrial truck of the lifting platform type, a load moving stanchion disposed to operate at each side of the truck platform to push or pull a load from or to the load supporting surface of the platform in a direction longitudinally of the truck, stanchion carrier means for each stanchion mounted on trackways on the platform disposed below the load supporting surface of the platform, load engaging means on the stanchions, a double acting hydraulic ram for operating each stanchion carrier means including a motion multiplying means connecting each ram to its stanchion carrier means, a source of hydraulic power on the truck, hydraulic lines extending from the power source to said hydraulic rams and controller means for selectively connecting the lines to said rams.

References Cited in the file of this patent UNITED STATES PATENTS 19,950 Richard Apr. 13, 1858 1,693,335 Damerell Nov. 27, 1928 2,008,324 Grab July 16, 1935 2,120,042 Remde June 7, 1938 2,132,612 Faries Oct. 11, 1938 2,408,284 Anthony Sept. 24, 1946 2,547,329 Lapham Apr. 3, 1951 2,621,812 Lull Dec. 16, 1952 2,681,518 Troop June 22, 1954 2,699,878 Avery Ian. 18, 1955