US517222A - Cushion for log-carriers - Google Patents

Description

(No Model.)-

F. 0. KILGORE. CUSHION FOR LOG CARRIERS.

Patented Mar. 27, 1894.

comumr.

UNITED STATES PATENT OFFICE.

FREDERICK O. KILGORE, OF MINNEAPOLIS, MINNESOTA.

CUSHION FOR LOG-CARRIERS.

SPECIFICATION forming part of Letters Patent No. 517,222, dated March 27, 1894.

Application filed February 16, 1893- Serial No. 46 2,576- (No model.)

To all whom it may concern:

Be it known that I, FREDERICK O. KILGORE, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Cushions for Log- Oarriages; and I do hereby declare the following to .be a full, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use the same.

My invention relates to cushions or buffers for saw-mill log-carriages.

The carriages herein especially referred to, are those used in saw-mills for feeding the logs to the circular or band-saws. As is wellknown, when in use, these carriages are usually manned by several operators, who ride, to-and-fro, upon the same while at work. These carriages when thus manned and loaded with logs, are of great weight. Inasmuch, as the return movement of the carriage from the saws, is all lost time, so far as work is concerned, it is very desirable that this return movement should be accomplished as rapidly as possible. Hitherto, so far as I am aware, this rapid return movement of the carriage has been greatly impaired and restricted from the conditions imposed by the wooden or rubber bumpers hitherto employed. If the carriage be run at full speed to near the limit of its travel before throwing off the power, and reliance be placed on the wooden or rubber bumpers to stop the same, the momentum would be so great as to break away the bu mpers, break or strain the carriage, dislocate the load and frequently cause serious accidents to the operators. To prevent such results, it has been the custom for the operator,in control of the carriage, to slacken or slow-up the speed of the same before reaching the bumper. Great caution is therefore required, and much time is lost in effecting the return movement of the carriage.

It is the object of my invention, to provide a buffing device, against which the carriage may be run at full speed, and be stopped by the bufiing action of the buffing device, without violent jar or shock either to the carriage or the buffing device.

My invention is illustrated in detail, in the accompanying drawings, wherein like letters refer to like parts throughout the several views.

Figure 1 is a side elevation, showing the truck portion of the carriage, provided with an extended buffer head, and the buffing device in position for cooperation therewith. Fig. 2 is a front end elevation of the buffing device. Fig. 3 is a vertical central longitudinal section of the buffing device, taken on the line X X of Fig. 2; and Figs. 4 and 5 are similar views to Fig. 3, showing a modified form of the butting device.

A represents the floor line of the mill.

B are the track-rails for the carriage, and O is the log-carriage movable over the same,

some parts of the carriage mechanism being omitted. The carriage O is provided, at its rear end with a centrally located and rear- Wardly projecting buffer-head D. This buffer-head may be of any suitable material, but is preferably made of wood and provided with a cap 11 of rubber or leather, to muflie the initial engagement of the same, with the piston of the buffing device, as will presently appear. The buffing device is in the nature of an air or steam cushion, comprisinga cylinder, andapiston working therein, the cylinder being rigidly secured to the floor A, at the limit of the carriages rearward movement, with its axis approximately in line with the longitudinal path of the buffer head D on the carriage.

E is the cylinder open at its front end, and provided with longitudinal laterally project ing securing lugs or flanges e, which are rigidly secured to supporting timbers F, rigid with the floor, by means of stay-bolts G passing through perforations in the lugs e, the timbers F and the floor A. The bolts may be secured by means of nuts, not shown, or in any other suitable manner.

H is an air or steam passage fitted with a check-valve h, located at the rear lower end of the cylinder E, adapted to prevent the escape of air or steam therethrough, from the cylinder and to permit the passage of air or steam into the cylinder under the action of the suction of the piston-head on its return or outward movement to normal position, as will presently appear.

K is the piston head, as preferably constructed, provided with a rod or stem K,pro-

jecting rearward from the head K and working through a seat or perforation in the rear end of the cylinder. The stem K is provided, at its outer rear end with a stop K in the form of a screw threaded nut, which stop limits the forward movementof both the pistonhead and stem.

L is a retracting spring bearing against the inner face of the cylinder head and acting against the back of the piston to throw the same into its outermost or normal position. The spring, as shown in Fig. 3, encircles the piston-rod K, but is of larger diameter than the rod and is held in position and properly centered by spuds K projectinginward from the piston and cylinder heads. These spuds would hold the spring, even if the piston rod should be dispensed with.

It should be noted, as an iinportantfeature of the construction, that the bu ffer-head D on the carriage, is much less in diameter than the piston head K, against which the head strikes in the bufiing action. In virtue of these relative dimensions, the buffer-head D does not require to be fitted oraccurately set; and if, the carriage body should shift laterally on its truck or otherwise, it will make no material difference. The buffer-head will still strike somewhere on the face of the piston.

The operation is evident. Near the limit of the rearward movement of the carriage,

'the buffer-head D comes into contact with the piston-head K of the buffing device and forces the same rearward, thereby tightly closing the check-valve h and compressing the volume of air confined in the cylinder back of the pistorrhead. At first, the recession of the piston head will be comparatively rapid; but the movement of the piston will be retarded with an increasing resistance from the compression of the air confined in the cylinder. Vhen the carriage is again moved away from the buffer, the compressed volume of air in the cylinder, it the pressure remains therein, will tend to throw the piston head forward into its normal position; but it is obvious that more or less leakage will, in time, be permitted through the variousjoints, as forinstance, around the piston head K, or through the seat of the piston rod K and therefore it will not do to rely on the air in the cylinder, for the return of the piston. The spring L is therefore provided to insure the positive return of the piston-head into its normal position; and a fresh charge of free air is permitted to enter through the air inlet H, and the check-valve h, as previously stated.

It is evident that the piston-rod K might work through a stuffing-box in the cylinderhead, to prevent leakage at that point, if deemed necessary or desirable.

Referring to the modification shown in Fig. 4, the cylinder-head is made solid, the pistonrod is dispensed with, the spuds K serve of themselves to hold the spring and the outward movement of the piston is limited by a suitable stop or stops, such for example, as an annular flange m, fixed to the outer end of the cylinder. Otherwise, the construction and op eration are the same, as the device shown in Figs. 1, 2, and 3.

Referring to the modification shown in Fi 5, an air-cushion in the form of adash-pot, is illustrated, with the piston P, secured to the end of the carriage C, and the bell-mouthed cylinder P, secured in a fixed position near the rearward limit of the carriages travel, in line with the piston P. The head of the piston P, is shown as provided with air-passages 1), covered by flexible valves 13, arranged to close the air-passages on the rearward movement of the piston P, and to open the same on the return or outward movement of the piston. This, of course, prevents the escape of air from the cylinder in the butting action and permitsa free entrance of the air behind the piston on its outward movement, thereby avoiding the suction, which would be caused by; the partial vacuum produced behind the piston on its outward movement. \Vithout this or some other form of valve, to permit the inlet of air on the outward movement of the piston, a partial vacuum would be caused, on account of the necessary leakage around the piston head in the bufling action.

In all the constructions shown,the cylinder has been shown as in the fixed position, and

the buffer-head or piston, as carried on the carriage. Butit will be understood, ofcourse, that the relative positions of these parts, might be reversed. In other words, the cylinder might be carried on the carriage and the co-o peratin g buffer-heads or piston, as the case may be, be secured in the fixed position in the path of the moving cylinder. It is equally obvious, that with the form of the device shown in Figs. 3 and 4, the piston-head K, might be provided with an outwardly extended projection, which would take the place of the buffer-head D and receive the stroke directly from the end of the carriage. The two forms of valve mechanism shown might be substituted, the one for the other, or any other suitable form of valve be provided in place of either form shown.

With the use of a cushion buffer, constructed in accordance with my invention, the log-carriage may be returned at high speed and be quickly stopped by the buffer, without jar or shock. It may even be run at full speed against the buffer, but the carriage driving power must, of course, be thrown off either coincident with or slightly before contact with the buffer.

The amount of care or caution required in operating the log-carriage is greatly reduced, the liability to accidents to the operators from the bufiing jars is removed, and the capacity of the circular or band-saw is greatly increased by the gain made in the time required for the return movement of the carriage.

For some reasons, it may be more desirable IIO to use steam than air, as the elastic medium for compression. Steam would be better than free air for the reason that it might be held at any desired pressure; and the initial check or resistance to the carriage could therefore be made of any desired amount. On all the forms of the device shown, except the dash pot illustrated in Fig. 5, steam may be applied by simply coupling on a steam supply pipe to the inlet H.

What I claim, and desire to secure by Letters Patent of the United States, is as follows:

1. The combination with a log-carriage, of the elastic fluid cushion, and cooperating buffer surface, one of which parts is carried on the carriage, and the other is fixed in the path thereof, the said fluid cushion comprising a cylinder provided with air openings at its forward end, and fitted with a piston for receiving the buffing stroke, a spring behind the said piston for returning the same outward to its normal position, and an air inlet to the cylinder, behind the said piston, fitted with a check valve, arranged to permit the said piston to work against a volume of fluid confined in the cylinder in the bufflng action, substantially as described.

2. The combination with the log-carriage, of an elastic fluid cushion buifer and co-operatingbuffing surface, one on the carriage and the other fixed in the path thereof, the said cushion buffer comprising an open ended cylinder with fluid inlet fitted with a check-valve, a piston working therein against the confined fluid to receive the buffing stroke and a spring behind the piston for throwing the same into its outermost or normal position, substantially as described.

3. The combination with the log-carriage, of an elastic fluid cushion and a buifer-head, one on the carriage and the other fixed in the path thereof, the said cushion comprising a cylinder fitted with a piston to receive the buffing stroke, the said buffer head being of relatively small diameter, as compared with the piston-head, substantially as and for the purpose set forth.

4:. The combination with the log-carriage, having a projecting buffer-head, of a co-operating elastic fluid cushion, in the path of the buffer-head, at the return limit of travel, the said cushion buffer comprising a fixed cylinder with open front end and having an inlet fitted with check-valve, a piston working in said cylinder against the fluid confined therein on the bnffing action, and a spring for returning the piston head, the said piston-head being of large diameter as compared with the cooperating buifer-head, substantially as described.

5. The combination with a log carriage 0 having an extended buffer-head D, of the fixed cylinder E having inlet H with checkvalve h, the piston K, rod K with external stop K and the spring L, all arranged and operating, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

FREDERICK O. KILGORE.

Witnesses:

J AS. F. WILLIAMSON, EMMA F. ELMORE.

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