US2918039A

US2918039A - Hydraulically actuated pressure foot for wood grinders

Info

Publication number: US2918039A
Application number: US678220A
Authority: US
Inventors: Herbert H Boje; Schulz August
Original assignee: Armstrong Cork Co
Current assignee: Armstrong World Industries Inc
Priority date: 1957-08-14
Filing date: 1957-08-14
Publication date: 1959-12-22
Anticipated expiration: 1976-12-22

Description

Dec. 22, 1959 H. H. BOJE ETAL 2,918,039

HYDRAULICALLY ACTUATED PRESSUREFOOT FOR WOOD GRINDERS 2 Sheets-Sheet 1 Filed Aug. 14, 1957 INVENTOR HERBERT H. BOJE AUGUST SCHULZ ATTORNEY Dec. 22, 1959 H. H. BOJE 'ETAL 2,918,039

HYDRAULICALLY ACTUATED PRESSURE FOOT FOR WOOD GRINDERS 2 Sheets-$heet 2 Filed-Aug. 14, 1957 INVENTOR HERBERT H. BOJE AUGUST SCHULZ ATTORNEY Patented Dec. 22, 1959 HYDRAULICALLY ACTUATED PRESSURE FOOT FOR WOOD GRINDERS Herbert H. Boje and August Schulz, Lancaster, Pa., as-

signors to Armstrong Cork Company, Lancaster, Pa., a corporation of Pennsylvania Application August 14, 1957, Serial No. 678,220

8 Claims. (Cl. 121-1) This invention relates to a hydraulic power unit for a pressure member and is concerned more particularly with a hydraulically actuated pressure foot for wood grinders.

Water is most frequently used as the hydraulic fluid for actuation of the pressure foot of wood grinders principally because of the possibility of leakage of other fluids, such as oil, contaminating the stock of wood fibers which are ground. Leakage in hydraulic-power units most frequently occurs at the packing joint between the piston and the end bell of the cylinder through which the piston rod passes. This failure at the joint packing is due quite frequently to the massive unbalanced weight of the pressure foot which is supported on the end of the piston rod and is disposed at a substantial angle, generally 90, to the axis of the piston rod and in a substantially vertical or slightly inclined plane. This unbalanced weight of the foot sometimes causes the packing to fail, and leakage occurs. With a conventional hydraulic actuated pressure foot, using water as the actuating fluid;

minor leaks are of no consequence, for the water which may get into the ground stock is not objectionable. Where oil is used, however, serious stock contamination may result from even minor packing failures.

Efforts have been made to overcome this leakage problem, and one solution is to support the pressure foot independently of the power unit so as to avoid the unbalanced weight and the problems which result from it. This may be accomplished by mounting the pressure foot on a sleeve which is slidable axially in suitable bearings. A compact unit may be provided by disposing the hydraulic power unit within the supporting sleeve.

One of the problems with this type of unit is the difficulty of making repairs to the actuating cylinder and piston power unit where much of the mechanism is mounted within the sleeve which is closed at its forward end by the pressure foot. The mechanism is quite massive in a conventional wood grinder for forming pulp for fiberboard manufacture, for instance, and may weigh several tons.

An object of the invention is to provide a fluid actuated power unit in which the actuated member, such as the pressure foot of a wood grinder, is supported and guided for its movement independently-of the actuating member, such as an oil hydraulic cylinder and piston motor, and in which the actuating member is arranged for convenient removal from the actuated member.

Another object of the invention is to provide a fluid actuated power unit in which the actuating member, such as the oil hydraulic cylinder and piston unit referred to above, is received within a sleeve which supports the actuated member, such as the pressure foot mentioned previously, during movement of the pressure foot, and in which the pressure foot is removably secured to the hydraulic power unit by fastening means which are readily accessible outboard with respect to the sleeve so that the hydraulic power unit may be removed from within the sleeve for repairs without removing the pressure foot from the sleeve.

Other objects of the invention will be clear from the following description of an embodiment of the invention which will be described in conjunction with the attached drawing, in which;

Figure l is a longitudinal cross sectional view of a hydraulically actuated pressure foot mechanism for a wood grinder, with the grinding stone shown diagrammatically;

Figure 2 is an end view, partly in section, showing the outboard end of the power unit of Figure 1;

Figure 3 is a longitudinal sectional view of the hydraulic power unit of Figure 1, partially broken away, and drawn to a somewhat larger scale than Figure 1, illustrating the actuating mechanism partially removed from within the pressure foot guiding sleeve;

Figure 4 is an end view of the power unit looking toward the pressure foot, a portion of which is shown in this view; and

Figure 5 is a sectional view taken along the line VV of Figure 3.

The unit includes a grinding stone 2, a wood pocket 3, i

and a pressure foot 4 which is movable through the pocket 3 to press bolts of wood received in the pocket into engagement with the stone 2. The foot 4 is actuated by a fluid pressure power unit 5 mounted within a housing 6. The housing 6 is supported upon a stand 7. A hopper 8 for the reception of bolts of wood to be ground is mounted above the pocket 3 and is closed at the bottom by a retractable gate 9 which may be actuated by a fluid pressure power unit 10.

The pressure foot 4 is supported for its reciprocatory movement independent of the power unit 5. This is accomplished by mounting the foot 4 on a cylindrical sleeve 11 which is received within housing 6 and is axially slidable with respect to it. The sleeve 11 has an annular mounting flange 12 welded onto its lower end, as shown in Figures 1 and 3, and the pressure foot.4 is bolted to this flange by bolts 13, as shown in Figures 4 and 5. The pressure foot 4 may be bored to receive the sleeve 11, and an annular supporting flange 14 may be provided on the pressure foot 4 surrounding the end of the sleeve 11, as shown in Figures 1 and 3.

The sleeve is guided for axial movement in a lower bearing 15 mounted in housing 6 and engageable with a machined surface 16 on the sleeve 11 and an upper bearing 17, which is carried by the sleeve 11 and slides along a machined inner cylindrical surface 18 in the housing 6. Oil seals 19 are provided to engage and seal against the machined surface 16 of the sleeve and are clamped against bearing 15 by a holding ring 20 secured to the housing 6. Similar seals 21 are provided to engage and seal against the machined surface 18 of the housing 6. These seals are clamped against bearing 17 by a holding ring 22 secured to sleeve 11.

The power unit 5 includes a cylinder 23 in which a piston is movable under the action of fluid, such as oil, applied under pressure. This cylinder and piston unit usuallyis a double acting power motor arranged to move the pressure foot 4 to bring bolts of wood deposited in pocket 3 into gripping relationship with rotating grinding stone 2 and then to press the bolts of wood into engagement with the stone under substantial pressure during grinding. The unit preferably is constructed so that the pressure foot 4 may be rapidly retracted upon completion of the grinding cycle and also arranged and controlled so that movement of the pressure foot into gripping position also may be eifected rapidly.

The end bell 24 of the power unit has a clevis connection 25 formed thereon which cooperates with a tongue 26 which projects from end cap 27 of the housing 6. The end cap 27 is secured to a flange 28 on housing 6 by bolts 29. A clevis pin 30 connects the

members

25 and 26 throu h a ball and socket connection 31 to provide for self adjustment of the power unit during movement of the sleeve 11.

Pistonrod 32 of the power unit has a threaded end 32' which is received within a threaded clevis connection 33. A mounting plate 34 is provided which has a tongue 35 welded thereon which cooperates with the clevis connec tion 33, and a clevis pin 36 and a ball and socket connection 37 similar to the connection at the opposite end of the power unit are provided to join the power unit to the mounting plate.

The mounting plate 34 is provided with a locating boss 38, and the pressure foot 4 is provided with a locating recess 39 for cooperation therewith. The mounting flange 12'attached to the sleeve 11 is recessed, as shown in Figure'5, to receive the ends of the plate 34; and fastening rods 40'and 41 of high tensile strength steel pass through openings provided in the plate 34 and are threaded into openings provided in the pressure foot 4, as shown in Figure 3.

The mounting plate 34 is secured to the foot 4 through the fastening and guiding rods 4i) and 41 by the use of seamless

steel'tube spacer members

42 and 43 which are received over the rods 40 and 41. The ends of the rods are threaded (Figure l), and nuts 4-4 and 45 clamp the

members

42 and 43 against the mounting plate 34.

The cap 27 of housing 6 is provided with openings 46 and 47 (Figure 3) covered by

dust caps

48 and 49, as shown in Figures 1 and 2. The

openings

46 and 47 provide access to the nuts 44 and 45 (Figure 1 which may be removed with the aid of a socket wrench inserted through the openings in the end cap.

The usual fluid pressure supply lines 50 and 51 for the power unit pass through the end cap 27, as shown in Figure 2, and are attached at the end bells of the power unit in the usual way, as indicated in Figure l.

A guiding plate 52 may be positioned over the holding ring 22, as shown in Figure 3, and may be secured to sleeve 11 by cap screws 53. The plate 52 is bored to receive the

tubes

42 and 43 which surround the rods 49 and 41 and will serve to hold these members against whipping and misalignment during removal of the power unit from within the sleeve 11 and reassembly of the power unit within the sleeve 11.

The power unit and the associated mechanism may be removed from within the sleeve 11 in the manner indicated in Figure 3 Where the unit is shown in a partially retracted position. The

cover caps

48 and 49 are first removed, and the nuts 44 and 45 are unscrewed from the rods 40 and 41. The bolts 29 which secure the end cap 27 to the housing are also removed. Suitable lifting and retracting equipment, such as a chain hoist mounted on a trolley, is connected to end cap 27; and the power unit which is'attached to the end cap 24 and carries the mounting plate 34 is retracted axially from within sleeve H. The rods 4% and 41 serve as guides during removal of the unit, the guiding plate 52 supporting the rods All and 41. When the unit is retracted to a position where the mounting-plate 34 is adjacent to the guiding plate 52, the cap screws 53 may be removed and the guiding plate retracted, permitting'the unit including the guiding plate 52 to pass from within the sleeve 11 and out of engagement with the rods 49 and 41.

When the unit is to be reinserted, the mounting plate 34 is positioned over the rods it? and 4 and the unit is guided into position, the guiding plate 52 is secured in position, and the unit is guided downwardly until the lecating boss 38 of the mounting plate 34 is fitted into the guiding and aligning recess 39 in the pressure foot 4. The nuts 44 and 45 are then applied and drawn down firmly, connecting the mounting plate 34 to the pressure foot 4 and thereby connecting the power unit 5 to the pressure foot for actuation. The bolts 29 are reinserted, connecting the cover cap 27 to housing 6, and fixing the cylinder 23 in position through the clevis connection to the end bell 24 of the power unit.

The fastening rods 40 and 41 are of adequate size to withstand the force of the power unit, should through some accident a bolt of wood become lodged between the rear surface of the pressure foot and the housing during retraction of the pressure foot.

The unit of this invention is so constructed and arranged that, should there be failure of the packings or other damage which may require removal of the power unit for repairs, such removal may be effected conveniently from the outboard end of the unit without dismantling the pressure foot and sleeve assembly. The hydraulic oil or other hydraulic fluid which might contaminate the stock, should a leak occur, is sealed against passage into the wood pocket; and thus the possibility of contamination is reduced to a minimum, making the use of an oil hydraulic system practicable for commercial wood pulp grinding.

We claim:

1. In a pressure member including a housing, a sleeve slidable within the housing, an actuated member connected to the sleeve, and a fluid pressure actuated power unit received within the sleeve for actuating said member, the combination of a mounting plate received within said sleeve and connected to one end of said power unit, a holding member connected to the other end of said power unit, connecting means securing said holding member to said housing, and means accessible from the outboard end of said sleeve with said holding member connected to said housing for removably securing said mounting plate to said actuated member.

2. In a pressure member including a housing, a sleeve slidable within said housing, and an actuated member connected to said sleeve for movement with it, the combination of a power unit demountably received within said sleeve and comprising a fluid actuated piston and cylinder motor, a mounting plate received within said sleeve and connected to one of said piston and cylinder, a holding member connected to the other of said piston and cylinder and to said housing, and means passing axially through said sleeve and accessible with said holding member connected to said housing for removably securing said mounting plate to said actuated member.

3. In a pressure member including a housing, a sleeve slidable within said housing, and an actuated member connected to said sleeve for movement with said sleeve, the combination of a power unit demountably received within said sleeve and comprising a fluid actuated piston and cylinder motor, a mounting plate received within said sleeve and connected to one of said piston and cylinder, a holding member connected to the other of said piston and cylinder and to said housing, a plurality of guide rods received within said actuated member and passing through said mounting plate and extending axially through'said sleeve for supporting and guiding said power unit' in assembly and disassembly within said sleeve, and means accessible with said holding member connected to said housing for removably joining said mounting plate to said actuated member for movement in unison by said power unit.

4. In a pressure member including a housing, a sleeve slidable within said housing, and an actuated member connected to said sleeve for movement with said sleeve, the combination of a power unit demountably received within said sleeve and comprising a hydraulic piston and cylinder motor, a mounting plate received within said sleeve and connected to one of said piston and cylinder, a holding member connected to the other of said piston and cylinder and to said housing, a plurality of guide rods received within said actuated member and passing through said mounting plate and extending axially through said sleeve for supporting and guiding said power unit in assembly and disassembly within said sleeve, and means accessible with said holding member.

gamma connected to said housing for removably joining said mounting plate to said actuated member for movement in unison by said power unit, said last named means comprising clamping means received on said rods and spacer tubes disposed between said mounting plate and said clamping means.

5. In a pressure member including a housing, a sleeve slidable within said housing, and an actuated member connected to said sleeve for movement with said sleeve, the combination of a power unit demountably received within said sleeve and comprising an oil-hydraulic piston and cylinder motor, a mounting plate received within said sleeve and connected to one of said piston and cylinder, a holding member connected to the other of said piston and cylinder and to said housing, a plurality of guide rods received within said actuated memher and passing through said mounting plate and extending axially through said sleeve for supporting and guiding said power unit in assembly and disassembly within said sleeve, a'plurality of spacer tubes received over said rods, guiding means for said rods and tubes disposed adjacent to the outboard end of said sleeve, and means accessible from the outboard end of said power unit with said holding member connected to said housing for removably joining said mounting plate to said actuated member for movement in unison by' said power unit.

6. In a pressure member including a housing, a sleeve slidable within said housing, and an actuated member connected to said sleeve for movement with said sleeve, the combination of a power unit demountably received Within said sleeve and comprising a hydraulic piston and cylinder motor, a mounting plate received within said sleeve and connected to one of said piston and cylinder, a holding member connected to the other of said piston and cylinder and to said housing, a plurality of guide rods received within said actuated member and passing through said mounting plate and extending axially through said sleeve for supporting and guiding said power unit in assembly and disassembly within said sleeve, a plurality of spacer tubes received over said rods, guiding means for said rods and tubes, means re-' movably securing said guiding means to said sleeve, and clamping means on said rods accessible with said hold- 6 slidable within said housing, and an actuated member connected to said sleeve for movement with said sleeve, the combination of a power unit demountably received within said sleeve and comprising a fluid actuated piston and cylinder motor, a mounting plate received within said sleeve and connected to said piston, an end cover connected to said cylinder and to said housing, a plurality of guide rods received within said actuated member and passing through said mounting plate and extending axially through said sleeve for supporting and guiding said power unit and mounting plate in assembly and disassembly within said sleeve, a plurality of spacer tubes received over said rods, guiding means for said rods and tubes removably secured to said sleeve, and clamping ing member connected to said housing for removably joining said mounting plate to said actuated member for movement in unison by said power unit.

7. In a pressure member including a housing, a sleeve nuts received on said rods and accessible through openings in said end cover for clamping said mounting plate to said actuated member through said spacer tubes.

8. In a hydraulically actuated pressure foot for wood grinders including a housing, a sleeve slidable within said housing, and a pressure foot connected to said sleeve for movement with said sleeve, the combination of a power unit demountaoly received within said sleeve and comprising a hydraulic piston and cylinder motor, a mounting plate received within said sleeve and connected to one of said piston and cylinder and arranged to be clamped to said pressure foot, an end cover connected to the other of said piston and cylinder and secured to the outboard end of said housing, a plurality of guide rods received within and secured to said pressure foot and passing through said mounting plate and extending axially through said sleeve and a portion at least of said end cover for supporting and guiding said power unit in assembly and disassembly within said sleeve, and means accessible with said end cover connected to said housing for removably joining said mounting plate to said pressure foot for movement in unison by said power unit, said last named means comprising a plurality of spacer tubes received over said rods, and clamping nuts received on said rods and pressing said spacer tubes into engagement with said mounting plate to join said mounting plate to said pressure foot.

References Cited in the file of this patent UNITED STATES PATENTS 1,623,936 Colley Apr. 5, 1927 1,905,224 Haas et al. Apr. 25, 1933 2,422,210 Reischl June 17, 1947