US3719349A - Shock absorbing cable connector for pallet loader head - Google Patents

Abstract

A CONNECTOR CONSTRUCTION FOR HOIST OR ELEVATOR CABLES WHICH RAISE THE LOWER A MOVABLE HEAD SUCH AS A VACUUM HEAD OF A PALLET LOADER. THE CONNECTOR ABSORBS THE SHOCK ENCOUNTERED IN LIFTING OR LOWERING A LOAD FROM A POSITION AT REST TO FULL SPEED DURING ONLY A FEW FEET OF MOVEMENT OF THE HEAD WITH ITS LOAD. THE CONNECTOR FOR EACH CABLE HAS A NUMBER OF INTERCONNECTING RELATIVELY MOVABLE MEMBERS WHICH SUPPORT THE LOAD AND THROUGH WHICH LIFTING OR LOWERING REACTIONS ARE TRANSMITTED BETWEEN CABLES AND HEAD. USUALLY FOUR CABLES ARE CONNECTED TO THE HEAD, ONE AT EACH CORNER. THE INTERCONNELCTING MEMBERS INCLUDE RUBBER BLOCK MEANS THROUGH WHICH THE EITIRE SHOCK LOAD IS TRANSMITTED IN SHEAR FROM A MEMBER CONNECTED TO A CABLE TO ONE CONNECTED TO THE HEAD. THE CONNECTOR ALSO HAS SPRING MEANS PERMITTING RELATIVE MOVEMENT BETWEEN RELATIVELY MOVABLE CONNECTOR MEMBERS AS THE ELEVATOR MOTOR COMES UP TO SPEED FOR RAISING OR LOWERING THE HEAD. THE NEW SHOCK ABSORBING CONNECTOR REDUCES THE SHOCK LOAD OR IMPACT AT THE START OF A LOWERING OPERATION, WHEN THE LIFT MOTOR COMES UP TO SPEED, TO 0.91 G, AND STOPS VIBRATION OF THE HEAD IN A LITTLE OVER ONE SECOND.

Description

6. K. DULANEY SHOCK ABSORBING CABLE CONNECTOR FOR PALLET LOADBR HEAD 2 Sheets-Sheet 1 Filed Sept. 15, 1971 INVENTOR GEORGE K. DULANEY 5 W & M

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llllL March 6, 1973 K, DULANEY wmm SHOCK ABSORBING CABLE CONNECTOR FOR PALLET LOADER HEAD 2 Sheets-Sheet 2 Filed Sept. 15 1971 FIG.2

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INVENTOR GEORGE K. DULANEY /uaw 8:

ATTORNEYS United States Patent 3,719,349 SHOCK ABSORBING CABLE CONNECTOR FOR PALLET LOADER HEAD George K. Dulaney, Cazenovia, N.Y., assignor to Diebold, Incorporated, Canton, Ohio Filed Sept. 15, 1971, Scr. No. 183,802 Int. Cl. 366d 5/00 US. Cl. 254-135 R 12 Claims A connector construction for hoist or elevator cables which raise and lower a movable head such as a vacuum head of a pallet loader. The connector absorbs the shock encountered in lifting or lowering a load from a position at rest to full speed during only a few feet of movement of the head with its load. The connector for each cable has a number of interconnecting relatively movable members which support the load and through which lifting or lowering reactions are transmitted between cables and head. Usually four cables are connected to the head, one at each corner. The interconnected members include rubber block means through which the entire shock load is transmitted in shear from a member connected to a cable to one connected to the head. The connector also has spring means permitting relative movement between relatively movable connector members as the elevator motor comes up to speed for raising or lowering the head. The new shock absorbing connector reduces the shock load or impact at the start of a lowering operation, when the lift motor comes up to speed, to 0.91 G, and stops vibration of the head in a little over one second.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to hoisting or elevator mechanism for the movable heads of pallet loaders; and more particularly to a connector construction for the cables which raise and lower a vacuum head of a pallet loader, and which absorbs a major portion of the shock to which the head is subjected as the hoist motor comes up to speed for raising and lowering a pallet loader head.

Description of the prior art Prior connector means for cables used to raise and lower the vacuum heads of pallet loaders have included first plate means connected -with the hoist cable, second plate means connected with the vacuum head, members connected to said first and second plate means and relatively movable with respect to each other axially of the cable, and spring means biased normally to hold the plates and connected members out of direct load transmitting engagement.

The prior connectors introduce a short time delay before the head is subjected to the impact of shock loading, while the spring means is being compressed, as the drive motor is coming up to speed when raising the head. Such time delay similarly is operative when a loaded head is lowered. However, the shock load involving engageable load transmitting members imparted to a loaded head being lowered can be as high as 6.57 G. This has required very large capacity vacuum pump means to be provided for pallet loader vacuum heads to supply the vacuum required to hold the loads on the heads during the impact of such shock loads. Without the excess pump capacity, the shock can cause separation of the load from the vacuum head holding the load.

These factors have substantially reduced the usable payload capacity, and speed of operation of pallet loaders, as compared with the actual capacity disregarding shock 3,719,349 Patented Mar. 6, 1973 loading; and there has been a need existing in the art for a long time for some way to reduce the shock load imparted to pallet loader vacuum heads in their operation, to eliminate oversized pumps, and to increase speed of operation.

SUMMARY OF THE INVENTION Objectives of the invention include providing a shock absorber construction effective to substantially reduce the shock load imparted to the vacuum head of a pallet loader as it starts to raise or lower in loaded condition; providing a new cable connector for pallet loader heads which incorporates shock absorbing capability of substantial magnitude; providing a new shock absorbing cable connector for pallet loader heads which substantially reduces the time and magnitude of vibration resulting from the impact of shock loading on a loaded pallet head; providing a new shock absorbing cable connector for pallet loaders which enables substantial reduction in the size of vacuum pumps required for the vacuum heads of pallet loaders; providing a new shock absorbing cable connector for pallet loaders which enables a substantial increase in the speed of operation of pallet loaders; and providing a new shock absorbing cable connector for pallet loader vacuum heads which eliminates difliculties heretofore encountered in the art, achieves the indicated objectives simply, effectively and inexpensively, and solves problems and satisfies needs existing in the art.

These objectives and advantages are obtained by the construction, the general nature of which may be stated as including in a cable connector for hoist or elevator cables which raise and lower a movable vacuum head of a pallet loader, base means including a base plate and shock mount means adjustably connected to the base plate; means for connecting the base means to a pallet loader vacuum head; hoist means including slack take up means, spring hold down means, and spring means reacting between the take up and hold down means biased normally to hold the take up and hold down means out of load transmitting engagement; the hoist means also including means adjustably connecting the take up means with the cable of an elevator mechanism; and rubber mount means connecting the shock mount means and hold down means.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention--illustrative of the best mode in which applicant has contemplated applying the principles-4s set forth in the following description and shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims.

FIG. 1 is a fragmentary perspective view of a pallet loader having a vacuum head supported by the new cable connector construction from hoist cables for raising and lowering the head;

FIG. 2 is a side elevation of one of the improved cable connectors showing the parts when the vacuum head is at rest;

FIG. 3 is a top plan view of the parts shown in FIG. 2;

FIG. 4 is an end view looking in the direction of the arrows 44, FIG. 3;

FIG. 5 is a fragmentary sectional view taken on the line 55, FIG. 2;

FIG. 6 is a view similar to FIG. 2 with the cable connector parts shown in the position assumed during a lifting operation, just as the load has been directly engaged by one of the cables;

FIG. 7 is an enlarged view similar to FIG. 6 showing continued lifting movement, with the parts in their relative positions just after the load has been directly engaged and showing the operation of absorbing the shock loading, certain parts being in section looking in the direction of the arrows 7-7, FIG. 3;

FIG. 8 is a fragmentary sectional view looking in the direction of the arrows 8-8, FIG. 7;

FIG. 9 is a fragmentary sectional view taken on the line 9-9, FIG. 7; and

FIG. 10 is a fragmentary diagrammatic view illustrating the improved cable connector construction at one corner of a vacuum head of a pallet loader.

Similar numerals refer to similar parts throughout the various figures of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT A typical pallet loader is illustrated at 1 in FIG. 1 and may include a frame 2 supporting a layer table 3 where a carton pattern may be formed from cartons delivered by a carton conveyor 4. An overhead track 5 is supported on the frame 2 along which a carriage 6 travels. Hoisting or elevator mechanism 7 is mounted on carriage 6 and a vacuum head 8 of the pallet loader is suspended by cables 9 from elevator 7. Preferably one cable suspends each corner of the vacuum head 8.

After a pattern of cartons, which may be corrugated board boxes filled with packaged material, is accumulated on the layer table 3, the vacuum head 8 is moved to a position above the patterned layer and then lowered onto the formed layer or tier of cartons. At this time the head 8, which has a negative pressure plenum chamber equipped with a centrifugal blower, is controlled to form a partial vacuum within the plenum chamber. Normal atmospheric pressure outside the chamber forces the layer, tier or pattern of cartons against the underside of the vacuum head 8 so that the carton layer is held thereto.

The vacuum head 8 then is moved to a position at one side or the other of the frame 2, such as to the left (FIG. *1) and the formed tier or layer 10 of cartons 11 is lowered onto a pallet 12, or onto layers 10 of cartons 11 in a patterned tier previously deposited on the pallet 12.

When the vacuum head 8 is at its lowest position above pallet 12, with the layer 10 of cartons 11 deposited on the pallet 12 or cartons 11 thereon, the vacuum to the head 8 is discontinued and the carton layer thus is released from the vacuum head 8. Head 8 then may be raised and moved back to a position above layer table 3 where another layer of cartons 11 may be accumulated in the desired pattern design.

Shock is imparted to the vacuum head 8 and to a layer 10 of cartons 11 supported by vacuum thereon, as the vacuum head 8 is raised above the layer table 3, or as the vacuum head 8 is lowered from the position shown in FIG. 1 toward a pallet 12 below the head 8. The improved cable connector, generally indicated at 13, is used to connect each cable 9 to a corner of the vacuum head 8, whereby the shock is absorbed or minimized, and the time and magnitude of vibration resulting from the impact of shock loading is reduced.

Each connector 13 has a base plate 14 which is bolted at 15 to the vacuum head 8 (FIGS. 2, 6 and 7). Tie rods 16 extend upward from plate 14 and their lower ends may be joined to plate 14 by threads 17 and welds 18 as shown in FIG. 9. The upper ends of tie rods 16 preferably are threaded at 19 and nuts 20 thereon support U-shaped shock mount member 21. The horizontal web 22 of member 21 is clamped to tie rods 16 by spacer sleeves 23, washers 24, and nuts 24a which react against the upper surface of member 22 to securely hold member 21 rigidly mounted on the upper ends of tie rods 16.

Rubber mounts 25 are bolted at 26 to the flanges 27 of U-shaped member 21 and to flanges 28 of U-shaped spring hold down member 29.

A cylindrical tubular member 30- is welded at 31 at its upper end to the central portion of web 32 of U-shaped member 29, and member 30 projects downwardly from member 29 through a central opening 33 in web 22 of shock mount member 21.

A coil spring 34 surrounds cylindrical member 30 and reacts between web 32 of hold-down member 29 and a slack take-up plate 35. Spring 34 normally biases the parts to the position shown in FIG. 2. Plate 35 is mounted at the lower end of spring guide tube 36 supported on tube collar 37 welded to the lower end of tube 36. A shaft 38 is threaded into tube 36 and is adjustably connected thereto by nut 39. Shaft 38 extends downward from socket member 40* within which the lower end of cable 9 is clamped.

The various parts of the cable connector are shown in FIGS. 2 and 4 in their relative positions with the head 8 at rest and cables 9 ready to raise or lower the vacuum head 8. A lifting or raising operation is illustrated in FIGS. 6 and 7. As the motor of elevator 7 comes up to speed rapidly, cables 9 will move in the direction of the arrow 41 (FIG. 6) until slack take-up plate 35 compresses spring 34 and engages the lower end of member 30 as shown in FIG. 6. As plate 35 moves upward there is relative movement between plate 35 and tie rods 16 which pass through openings 35a in plate 35.

As cables 9 are raised further, indicated by the arrow 42 in FIG. 7, plate 35 and member 30 raise spring holddown member 29 upward with respect to shock mount member 21, causing distortion of rubber mounts 25 which connect members 29 and 21. The lifting forces, however, are transmitted in shear through the rubber mounts 25 to the shock mount member 21 and from member 21 through tie rods 16 to base plate 14 and vacuum head 8.

The vacuum head 8 on being lowered, for example from the position of FIG. 1 toward the pallet 12, involves somewhat the reverse of conditions that are involved in raising the head 8, as just described. The vacuum head 8 and layer 10 of cartons 11 supported thereon and ready to be lowered comprise a load which moves the parts of the cable connector 13 to the position shown in FIG. 6 with the head -8 at rest as shown in FIG. 1.

Operation of the elevator 7 to lower the head 8 initially involves operation of the elevator drive motor to come up to lowering speed. This results in a sudden dropping of cables 9 and their cable connectors 13. The springs 34 take up the rapid downward movement of the cables until slack take-up plates 35 of the connectors 13 move to the position of FIG. 2. Meanwhile, support for vacuum head 8 has been removed and the head 8 starts to drop rapidly accompanied by shock loading between cables 9 and vacuum head 8 amounting to about 0.91 Gs as measured using the improved cable connector construction. During this shock loading, vibration due to relative movement between members 21 and 29 occurs, which is stopped in a little over one second by the rubber mount 25 connection between members 21 and 29.

Measurements also have indicated that the vibrations have substantially reduced magnitude as compared with prior art cable connectors. Measurements of the operation of prior art cable connectors indicate a shock loading of 6.57 GS is encountered as the elevator drive motor comes up to speed on lowering a head; and vibration of great magnitude continues for many seconds.

' In accordance with the new concept of the invention, all forces for lifting or lowering a loaded vacuum head 8 are transmitted from elevator cables 9 to the vacuum head 8 through the rubber mounts 25 in shear. This enables the shock loading to be absorbed rapidly by the rubher, with vibrations of relatively small magnitude.

The tie rods 16 and spacer sleeves 23 extend through openings 32a in web member 32 of hold-down member 29; and washers 24 at the upper ends of the tie rods 16 will engage the top of web member 3 2 in the event of any accidental failure of rubber mounts 25, so as to prevent dropping the load upon complete separation of the load transmitting members of the cable connector 13.

The improved shock absorbing cable connector construction can be operated at high elevator drive motor speeds without dropping the load due to the impact of shock loading on starting movement of the head. Further, the reduction in the magnitude of shock loading resulting from the use of the improved construction has permitted smaller capacity vacuum pumps to be used for the vacuum heads of pallet loaders.

Accordingly, the improved construction has reduced the shock load impact on pallet loader vacuum heads in their operation, has eliminated the requirement for over-sized pumps for pallet loader vacuum heads, and has substantially increased the speed of operation of pallet loaders; all of which have greatly increased the usable payload capacity of pallet loaders. Thus, the improvements of the invention provide a construction which eliminates difficulties heretofore encountered in the art, which achieves the stated objectives simply, effectively and inexpensively, and which solves problems and satisfies needs that have existed in the art.

In the foregoing description certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described, since the features of the invention may be applied to different sized pallet loaders, cable connectors and vacuum heads.

Having now described the features, discoveries and principles of the invention, the manner in which the improved construction is made, the characteristics and op eration of the new construction, and the advantageous new and useful results obtained; the new and useful structures, devices, elements, arrangements, parts, combinations, and subcombinations are set forth in the appended claims.

I claim:

1. In shock absorbing cable connector mechanism for the vacuum head of a pallet loader, bases means including a base plate and shock mount means adjustably connected to the base plate; means for connecting the base means to a pallet loader vacuum head; hoist means including slack take-up means, spring hold-down means, and spring means reacting between the take-up and hold-down means biased normally to hold the take-up and hold-down means out of load transmitting engagement; the slack take-up means and the spring hold-down means being movable relative to each other, and each being movable relative to the shock mount means; the hoist means also including means adjustably connecting the take-up means with the cable of an elevator mechanism; and rubber mount means forming the sole connection between the shock mount means and hold-down means.

2. The construction defined in claim 1 in which the base means includes tie rods mounted on and extending upwardly from the base plate, and nut and spacer sleeve means adjustably mounted on the upper ends of the tie rods and engaging the shock mount means to form the adjustable connection between the shock mount means and base plate; in which openings are formed in the spring hold-down means; and in which the upper ends of the tie rods and the spacer sleeve means thereon extend through said openings.

3. The construction defined in claim 2 in which the shock mount means includes a U-shaped member having a web and a flange extending from each end of the web; in which the nut and spacer sleeve means engage the web; and in which washers are mounted at the upper ends of the spacer sleeve means engageable with the spring holddown means above the openings therein.

4. The construction defined in claim 1 in which bolts engage the base plate and form the means for connecting the base means to a pallet loader vacuum head.

5. The construction defined in claim 1 which the hoist means includes a slack take-up plate having openings therein, a cable clamp socket member, and adjustable means connecting the take-up plate and socket member and forming the means adjustably connecting the take-up means with the cable of an elevator mechanism.

6. The construction defined in claim 5 in which the means adjustably connecting the take-up plate and socket member includes a guide tube, and a shaft connected with the socket member and extending into said tube in adjustable threaded engagement therewith.

7. The construction defined in claim 6 in which the base means includes tie rods mounted on and extending upwardly from the base plate; in which the slack takeup plate has openings formed therein; and in which the tie rods extend through said slack take-up plate openings to permit relative movement therebetween.

8. The construction defined in claim 1 in which the spring hold-down means includes a U-shaped member having a web and a flange extending from each end of the web; in which openings are formed in the web; in which the base means includes tie rods mounted on and extending upwardly from the base plate; and in which the upper ends of the tie rods extend through said web openings.

9. The construction defined in claim 8 in which a tubular member is mounted on and extends downwardly centrally from the hold-down,member web; in which the spring means surrounds said tubular member; in which the hoist means includes a spring guide tube adjustably connected with the take-up means and cable; and in which the spring guide tube extends through said tubular member.

10. The construction defined in claim 1 in which the spring hold-down means includes a U-shaped member having a web; in which the slack take-up means includes a movable plate; and in which the spring means reacts between said web and movable plate.

11. The construction defined in claim 1 in which the means adjustably connecting the take-up means with the cable of an elevator mechanism includes a cable socket member adapted to be clamped to a cable; a shaft extending downward from the socket member; a spring guide tube forming part of said slack take-up means; and a nut-clamped, adjustable threaded connection between said shaft and said spring guide tube.

12. The construction defined in claim 1 in which the shock mount means includes U-shaped member having a web and a flange extending from each end of the web; in which the spring hold-down member includes U-shaped member having a web and a flange extending from each end of the web and located outside of and spaced from the shock mount means flanges; and in which rubber mount members are connected to and extend between adjacent flanges of the shock mount means and spring hold-down means U-shaped members.

References Cited UNITED STATES PATENTS 2,941,675 6/1960 Noble et al 29465 X 3,651,957 3/1972 Ball et al 294-64 R X 3,650,498 3/1972 Deak 24818 EVON C. BLUNK, Primary Examiner J. D. CHERRY, Assistant Examiner US. Cl. X.R.

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