STRETCHER WITH REMOVABLE PRESSURE BLOCK

Abstract

A stretcher has two head housings, and a removable pressure block/clamp assembly which is located in the housings and positioned via hydraulic cylinders. The hydraulic cylinders raise the pressure block assembly, and the gripper hydraulic cylinders lower the pressure block assembly onto a removal fixture which moves into and out of the head housing.

Claims

1. A stretcher with a removable pressure block assembly comprising: a head housing; a pressure block assembly which is located in said housing and positioned within said housing via hydraulic cylinders; said hydraulic cylinders raise said pressure block assembly; and said hydraulic cylinders lower said pressure block assembly to move said pressure block out of said housing.

2. The stretcher of claim 1, further comprising a window formed in a wall of said housing for accessing gripper plates within said housing for removal.

3. The stretcher of claim 2, wherein said gripper plates comprises upper gripper plates and lower gripper plates.

4. The stretcher of claim 3, wherein said lower gripper plates remain fixed in said housing.

5. The stretcher of claim 3, wherein said upper gripper plates move up and down relative to said housing.

6. The stretcher of claim 3, wherein said pressure block assembly comprises at least one piston which applies gripping force onto said lower gripping plates.

7. The stretcher of claim 6, wherein said pressure block assembly further comprises hydraulic piping for providing hydraulic fluid to said at least one piston.

8. The stretcher of claim 1, further comprising a removal fixture wherein said removal fixture comprises rollers for moving said removal fixture into and out of said housing.

9. The stretcher of claim 1, wherein said hydraulic cylinders lower said pressure block assembly onto said removal fixture.

10. The stretcher of claim 9, further comprising a mechanism to pull said pressure block assembly out of said head housing.

11. A stretcher with a removable pressure block assembly comprising: a head housing having a window in a side wall to access gripper plates; a pressure block assembly which is located in said housing and positioned by hydraulic cylinders which raise the pressure block assembly and lower said pressure block assembly for removing said pressure block assembly from said head housing.

12. The stretcher of claim 11, wherein said gripper plates comprises upper gripper plates and lower gripper plates.

13. The stretcher of claim 12, wherein said lower gripper plates remain fixed relative to said head housing.

14. The stretcher of claim 12, wherein said upper gripper plates move up and down relative to said head housing.

15. The stretcher of claim 12, wherein said pressure block assembly comprises at least one piston which applies gripping force through said upper gripper plates onto said lower gripping plates.

16. The stretcher of claim 15, wherein said pressure block assembly further comprises hydraulic piping for providing hydraulic fluid to said at least one piston.

17. The stretcher of claim 11, further comprising a removal fixture for moving said pressure block assembly out of said head housing.

18. The stretcher of claim 17, wherein said hydraulic cylinders lower said pressure block assembly onto said removal fixture.

19. The stretcher of claim 18, further comprising a mechanism to pull or push said pressure block assembly out of said head housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a perspective view of a stretcher head housing and removable pressure block/clamp assembly in accordance with a preferred embodiment of the disclosure.

[0025] FIG. 2 is a front elevational view of the stretcher head housing of FIG. 1 in accordance with another aspect of the disclosure.

[0026] FIG. 3 is a side elevational view of the stretcher head housing in accordance with another aspect of the disclosure.

[0027] FIG. 4 is a perspective view of the gripper plate removal stand.

[0028] FIG. 5 is a side elevational view of the stretcher head housing and the pressure block outside of the housing in accordance with another aspect of the disclosure.

[0029] FIG. 6 is a perspective view of a stretcher head housing and pressure block of FIG. 5.

[0030] FIG. 7 is a perspective view of a removed pressure block/clamp assembly of FIG. 6.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0031] Reference numerals are used to describe the components of the disclosure: [0032] 1 Main housing [0033] 2 Pressure block/clamp assembly positioning cylinder [0034] 3 Gripper change window [0035] 4 Pressure block/clamp assembly [0036] 5 Gripper plate [0037] 6 Gripper plate removal stand [0038] 7 Hydraulic piping [0039] 8 Removal fixture [0040] 9 Hydraulic hose carrier [0041] 10 Removal winch [0042] 11 Side blocks [0043] 12 Rollers [0044] 13 Side wall [0045] 14 Piston [0046] 15 Piston [0047] 16 Piston [0048] 17 opening [0049] 18 opposite side [0050] 19 opposite side [0051] 21 upper gripper [0052] 23 lower gripper

[0053] Referring now to FIGS. 1-7, a stretcher head housing 1 with a removable pressure block/clamp assembly 4 is shown, in accordance with a preferred embodiment of the disclosure. The pressure block 4 is pulled into an operating position by pressure block positioning hydraulic cylinders 2. The cylinders 2 extend through openings 17 formed in the top of housing 1 and pull up the pressure block 4 via blocks 11 located on opposite sides 18, 19 of the housing. The cylinders 2 lift and hold the pressure block in the raised operating position (with an air gap below the pressure block) as seen in FIGS. 1, 2 and 3. The cylinders 2 can also lower the pressure block onto a pressure block removal fixture 8 (seen in FIG. 5) which has rollers 12 which rolls into and out of the housing to receive the pressure block for installation and removal. Alternately, the pressure block can have wheels directly mounted to the pressure block for removal.

[0054] Referring to FIGS. 3 and 4, a gripper change window 3 is provided in a side wall 13 of the stretcher housing 1 to access the gripper plates 5 for removal and changing out using a gripper plate removal stand 6. The gripper plates 5 are of a metal construction and may include slots to add cardboard or chipboard may need to be changed out as needed (see Butech U.S. Pat. No. 9,327,334 incorporated by reference herein).

[0055] Metallic grippers typically get changed out every 6-12 months for maintenance or refurbishment, while cardboard or chipboard grippers get changed out after every three, four or five coils of sheet metal.

[0056] There are two upper grippers 21 and two lower grippers 23. In the preferred embodiment, the lower grippers remain fixed, while the upper grippers move up and down, to grip the material to be stretched. Alternatively, the lower grippers can move while the upper grippers remain fixed, or both the upper and lower grippers can move.

[0057] Referring now to FIG. 6, the pressure block/clamp assembly 4 has three (or more or less) pistons 14, 15 and 16 located at the upper wall of the pressure blocks which apply the gripping force straight down onto the gripper plates. Pressure block hydraulic piping 7 provides the hydraulic fluid to the pistons. A hydraulic hose carrier 9 is provided for the pressure block. A pressure block removal fixture 8 is provided for receiving the pressure block for removal from the stretcher housing 1.

[0058] Referring now to FIG. 5, rollers 12 on the fixture 8 enable the fixture 8 to be rolled into position under the elevated pressure block in the stretcher housing 1. The pressure block is then lowered via cylinders 2 onto the removal fixture. Referring to FIG. 7, for example a pressure block removal winch 10 (or hydraulic cylinder) is preferably used to pull the pressure block out of the stretcher housing 1.

[0059] The Figures illustrate a pressure block at the exit moving head of the stretcher. There is also a pressure block at the entry fixed head of the stretcher.

[0060] A detailed description of the removal and installation of the pressure block is now provided.

[0061] To install the pressure block 4 onto the stretcher, both upper and lower grippers and gripper retainers are removed. The pressure block positioning cylinders are fully extended. The stretcher is fully extendedonly when installing the pressure block in the moving head. The pressure block is then placed on the removal fixture 8, with care being used to center it with the heads as close as possible. The winch assembly 10 is placed on the opposite side of the stretcher. A wire rope supplied with the winch is attached to an eyebolt on the removal fixture 8. The winch cable is then fed through the stretcher and hooked or attached to the wire rope. The pressure block is carefully pulled into the stretcher head. Once the pressure block is fully seated, the pressure block pull back cylinders 2 are retracted to pull the block into place.

[0062] To remove the pressure block from the stretcher, both upper and lower grippers and gripper retainers are removed. The stretcher is fully extendedonly when removing the pressure block in the moving head. The removal fixture 8 is placed on a conveyor and it is pushed into the head until it stops under the pressure block. The pressure block positioning cylinders 2 are fully extended to lower the pressure block onto the removal fixture 8. The winch assembly 10 is placed on the same end of stretcher as the pressure block. The winch cable is attached to the (removal) eyebolt on the cart. The pressure block is carefully pulled out of the stretcher head.

[0063] The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment and the claims be construed as including all such modifications and alterations insofar as they come within the scope of the above disclosure and claims or the equivalents thereof.