US787374A - Emergency-brake for sawmill-carriages. - Google Patents

Description

No. 787,874. PATENTED APR. 18, 1905. j

J. L. GRAHAM.

EMERGENCY BRAKE FOR SAWMILL CARRIAGES.

APPLICATION FILED DEG.27,1904.

4 SHEETS-SHEET 1.

WITNESSES: j Z/m/ INVENTOR yw p/flax ATTORNEY I PATENTED APR.18, 1906.

J. L. GRAHAM.

EMERGENCY BRAKE FOR SAWMILL CARRIAGES.

APPLICATION FILED DEG.27,190-1.

INVENTOR WITNESSES:

J. L. GRAHAM.

EMERGENCY BRAKE FOR SAWMILL GARRIAGES.

APPLICATION FILED DEG.27,1904.

4 SHEETS-SHEET 3.

WITNESSES: g W 1/ INVENTOR a? BY A M ATTORNEY No. 787,374. PATBNTED APR. 18, 1905.

J. L. GRAHAM. EMERGENCY BRAKE FOR SAWMILL GARRIAGES.

APPLICATION FILED DEC 27, 190-1.

4 SHEETSSEEET 4.

WITNESSES: INVENTOR ATTORNEY UNTTED STATES Patented April 18, 1905.

ATENT @FFTCE.

JOHN L. GRAHAM, OF HAAKlVOUl), HlCIllGA N.

SPECIFICATION forming part of Letters Patent No. 787,374, dated April 18, 1905, Application filed December 2'7, 1904. Serial No. 238,487.

To u/f II/II)III- it may concern.-

Be it. known that I, Join? L. GRAHAM, a citizenof the United States, residing at Haakwood, in the county of Cheboygan and State of Michigan, have invented certain new and useful Improvements in Emergency-Brakes for Sawmill-(Iarriages; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to a safety device for quickly stopping a sawmill-carriage, and is especially adapted to that class of sawmillcarriages operated by a device commonly known as a steam-feed, consisting in a long horizontal steam-cylinder bolted to the mill structure and having a piston to which is attached a long piston-rod, the outer end of the piston-rod being connected to the sawmill-carriage to traverse it rapidly back and forth.

lit has frequently occurred that an accident to the valve which controls the admission of steam to the steam-feed cylinder causes the sawyer to lose control of the carriage, resulting frequently in a wreck and serious injury to the operators who ride on the carriage.

This invention embodies means whereby the piston-rod of the steam-feed will be instantly and powerfully clamped and brought to rest as soon as the sawyer releases his hold on the lever that controls the movement of the sawmill-carriage.

The invention is illustrated in the accompanying drawings, in which- Figure l is a front end view of the steamfeed cylinder and clamping device. Fig. 2 is a side elevation of the same. Fig. 3 is a top plan view, and Fig. l is a perspective, showing the levers by which the clamping device is operated.

A is any ordinary steam-feed cylinder, such as is now in common use, and B is the pistona'od, to the outer end of which the sawmill-carriage is secured. The carriage is omitted from the drawings for the sake of' clearness.

U is the sawyers lever, which, as commonly used, operates only to admit steam to either end of the cylinder A by properly actuating the admission-valve of the cylinder. 7

In this invention I employ the lever C to perform the additional function of a safetylever, whereby the steam-feed rod may be forcibly gripped and brought to rest as soon as the sawycr releases his hold on the lever. This safety-feed may be embodied in the le ver (3 in various ways; but I have illustrated only one construction to accomplish the desired results. This device is illustrated in Fig. 1, where the handle C is made hollow and provided with a vertically-movable hand piece or grip C, which rests like a cup on the top of the lever. A spring (1* is interposed between the top of the lever and the grip C and is normally compressed by the weight of the sawyers hand resting upon it. \Vhen so compressed, the grip (IV pushes down on the rod C within the lever (,7 and operating through the bellcrank lever l) operates the steam-valve E, which may be of any suitable construction to admit steam through the pipe F to the lower end of a short steam-cyliiuler G, thereby pushingup the piston lliof the cylinder G and its red ll. To the upper entfof the rod Ii is fastened a l avy metal st rap l, carrying a clamping-shoe J, adapted to [it the upper circumference of the steam-feed rod B.

\Vhen the sawyers hand is released from the grip C, the spring rises, pulling up the rod U and drawing back the bell-crank fever ,1), thus opening the pipe F to exhaust and admitting steam to the pipe K, which communicates with the cylinder (l above the piston H. The piston-rod It and the clampingshoe J are immediately pulled down, and the shoe J clamps the piston-rod down tightly upon the lower block L, quickly stopping the movement of the rod.

To further increase the ellicieney of the device, I have added to the clamping means above described a device for shutting off the supply of steam to the steam-feed cylinder simultaneously with the operation of the clamping device.

In Fig. 1, M represents the. steam-main through which the steam is supplied from the boilers to the Valve of the steam-feed cylinder A. The pipe connections are not shown, as their arrangement varies under different conditions.

I provide in the pipe M a suitable shut-01f valve N, having a valve-rod N connected to a bell-crank lever O, the other end of the lever being connected to a bell-crank leverP, which in turn is pivoted to the downwardly-extending arm of a bell-crank lever Q and the other end of which is pivoted to the piston-rod H. The lever Q is carried by a suitable pivoted link R.

The operation of the device is as follows: When the operator releases his hold on the grip C and the piston-rod II and the shoe J drop as previously described, the bell-crank lever Q operates the link P and the bell-crank lever O to move the valve-stem N of the valve N, thereby shutting off the supply of steam through pipe M.

While I have described and illustrated cer tain specific mechanisms for accomplishing the desired result of gripping the steam-feed rod when the sawyer releases his hold on the controlling-lever, I do not desire to confine myself to these particular constructions.

What I claim as my invention, and desire to secure by Letters Patent, is as follows:

1. The combination with the piston-rod of a steam-feed of a clamp adapted to rip said piston-rod a sawyers operatingever; a movable handpiece carried by said lever and means connecting said handpiece to said clamp and adapted to automatically actuate said clamp to grip said piston-rod when the sawyer s hand is removed from the operatinglever.

2. The combination with the piston-rod of a steam-feed of a clamp adapted to grip said piston-rod a valve in the steam-pipe leading to the steam-feed; a sawyers operating-lever; a movable handpiece carried by said lever; and means connecting said handpiece, clamp and valve, said means being adapted to automatically actuate said clamp to grip the piston-rod and to actuate said valve to shut off steam in said main steam-pipe when the sawycrs hand is removed from the operating-lever.

3. The combination with the piston-rod of a steam-feed of a clamp adapted to grip said piston-rod; a sawyers operating-lever; a cap slidably mounted on top of said operating lever; a bell-crank lever pivotally mounted on said operating-lever; and means connectin said cap with said bell-crank lever; a valve actuated by said bell-crank lever; a

cylinder with a movable piston and means connecting said movable piston with said clamp and adapted to actuate the clamp to grip the said steam-feed piston-rod when the sawyers hand is removed from said operating-lever.

4. The combination with a steam-feed piston-rod; of a clamp adapted to grip said piston-rod; a sawyers operating-lever; a cap slidably mounted on top of said operatinglever; a bell-crank lever pivotally mounted on said operating-lever; a movable rod connecting said cap with said bell-crank lever; a valve actuated by said bell-crank lever; a cylinder with a movable piston and means for connecting either end of said cylinder successively with said valve; and means connecting said piston with said clamp.

5. The combination with a steam-feed piston-rod, of an operating-lever; a cap mounted on said operating-lever; a bell-crank lever mounted on said operating-lever; and means for connecting the cap with said bell-crank lever; a valve actuated by said bell-crank lever; a cylinder with a movable piston and means for connecting either end of said cylinder successively with said valve; a pistonrod secured to said movable piston; a clamp comprisinga lower stationary block adapted to support said steam-feed piston-rod, and an upper movable block and means connecting said movable block with said pistonrod, substantially as and for the purposes set forth.

6. The combination with a steam-feed cylinder, piston and piston-rod; of an operating-lever; a valve and means connecting said operating-lever to said valve and adapted to actuate said valve; a cylinder having a movable piston and means for connecting either end of said piston alternately with said valve; a piston-rod secured to said movable piston;

a clamp adapted to grip said piston-rod and I means for connecting said piston-rod with said clamp; together with a valve in the steam-supply pipe of said steam-feed cylinder and means connecting said movable piston to said valve, for closing said valve when the piston moves down, substantially as described.

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

JOHN L. GRAHAM.

Witnesses:

J. STANLEY SEE, J. R. MANsFIELD.

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