US1978011A - Mechanical unloader for stokers - Google Patents

Description

Oct. 23, 1934.

H. C. CARTER MECHANICAL UNLOADER FOR STOKERS Filed Feb. 23, 1932 2 Sheets-Sheet l NWAEA/TU H c CARTER 7 7- TERA/E K Oct. 23, 1934.

1 H. c. CARTER 1 1,978,011

MECHANICAL UNLOADER FOR STOKERS Fi led Feb. 25, 1952 2 Sheets-Sheet 2 4 TTURNEW mechanism illustrated Patented Oct. 23, 1934 MECHANICAL UNLOADER FOR STOKERS Haskell 0. Carter, Portland, 0reg., assignor to Iron Fireman Manufacturing Company, Port-.

land, Oreg.

Application February 23, 1932, Serial No. 594,411

3 Claims.

This invention relates generally to underfeed stokers, and particularly to a mechanical unloader therefor.

The main object of this invention is to provide a simple and eflicient means for moving an overload from the driving mechanism of the stoker, with particular reference to the type of driving in Patent Number 1,779,824, dated October 28, 1930, to C. J. Parker.

The second object is to construct an unloading device which cannot be easily tampered with or rendered inoperative, and which will include means forgiving notice, either audibly or visibly, that the device has functioned and, if desired, stop the operation of the stoker motor.

These, and other objects, will become more apparent from the specification following as illustrated in the accompanying drawings, in

which:

Fig. 1 is a front elevation of a stoker gear case with parts of the mechanism broken away in.

section.

Fig. 2 is an elevation of the gear case with the front cover removed and showing certain parts cut away in section.

Fig. 3 is a side elevation of a gear case and fuel magazine with parts broken away along the line 3--3 in Fig. 1.

' Fig. 4 is a section taken along in Fig. 1.

Fig. 5 is a fragmentar view showing a modified form of the device including the signal and motor control.

Fig. 5 is a fragmentary view showing a modification with parts broken away in section.

Fig. '7 is a fragmentary section taken along the line '7-'7 in Fig. 6.

Fig. 8 is a section taken along the line 8-8 in Fig. '7.

Similar numbers of reference refer to similar parts throughout the several views.

Referring in detail to the drawings, there is shown a portion of a hopper 10 of an underfeed coal stoker and also a worm 11 by means of which fuel is conveyed from the hopper to the combustion zone. To the hopper 10 is attached a gear case 12 to which power is delivered by a motor (not shown) through a shaft 13 and, as described in the above-mentioned patent, to a shaft 14 on which is mounted a gear 15 whose hub 16 is secured on the shaft 14 by the heavy shear pin 17.

The gear 15 meshes with any one of the three pinions 18, 19 or 20 whose respective shafts 21 the I line '44-.

are carried in a rotatable cage 22. Attached t0 second the pinion 18 is a gear 23. Attached to the. pinion 19 is a gear 24. Attached to the pinion 20 or integral therewith is a gear 25 equal in diameter to the pinion 20. The gears 23, 24 and 25 mesh at all times with the pinion 26 which is directly connected to'the worm 11.

The cage 22 is provided-with a plurality of notches 2'7 and 28 alternating about-the periphery .thereof and adapted to receive the latch point 29 of the arm 30, which is secured to the rock shaft 31 bymeans of a pin 30-A which journals in the gear case front 32 and has attached on the outer end thereof by means of a shear pin 33 a lever 34 whose handle 35 is normally urged in an upward direction by the spring '70 36. The spring 36 is placed on the rod 3'7 whose lower end is attached to the lever 34 and whose lower end passes through the lug 38 which forms a support for the spring 36. The upper end 39 is threaded to receive the nuts 40 by means of which the compression of the spring 36 may be varied. I

The angle of the side of the notches 28 and the compression of the spring 36 are so proportioned as to provide for the handling of ordiso nary loads on the worm 11, but should this load become excessive the cage 22 will become unlatched permitting the gear 15 to disengage the particular pinion with which it may be in mesh, and the rotation of the cage 22 is stopped by 35 the latch point 29 dropping into the next notch 27, thereby holding the gear set in a neutral position from which it cannot be changed until the handle 35 is depressed and the cage 22 rotated by means of the dial 41.

It is desirable that the pin 33 shall be more easily sheared than the pin 30-A in order that if too much compression is placed on the spring 36, or the lever 34 is prevented from movement by a plug between same and the floor, or in any other manner that an excessive load will shear the pin 33, which is on the outside of the gear case and therefore readily accessible.

Referring now to Fig. 5 it will be seen that the lever 34'-A is provided with a notch 42 which engages the lug 43 of a forked rocker arm 44 arranged to operate a toggle switch 45 in the circuit 46, which may be made to include any or all of three electrically operated devices, namely an alarm bell 4'7, a lamp 48 or an electrically oper- 05 ated switch 49 for opening the motorcircuit 50.

In this form of the device whenever the lever 34-A drops by reason of an overload having caused the latch point 29 to be withdrawn from its respective notch 28, the rocker arm 44 will actuate the switch 45 and announce the fact, either audibly or visibly, that the coal feed has stopped, and at the same time will stop the operation of the motor thereby preventing its unnecessary operation, and at the same time, and more important, preventing the operation of the fan which would otherwise cause all of the fuel in the retort to be burned, to the detriment of the tuyere elements themselves. I

In Figs. 6 to 8 inclusive the cage 51 is prevented from being driven by a latch arm 52 provided with a hardened face 53 which engages the shoulders 54 disposed about the periphery of the cage 51. The arm 52 is supported by a stub shaft 55 which journals in the hub 56 of the gear case front 57. The hub 56 is provided with a slot 58' which receives the pin 59. The pin 59 passes through the shaft 55 and holds it in place within the hub 56. The slot 58 permits a limited rocking movement of the shaft 55. The shaft 55 is provided with a square end 60 for the application of a key or wrench for manually unlatching the cage 51. The arm 52 is urged toward the cage 51 by means of a compression spring 61 within the housing 62. The compression of the spring 61-may be varied by the set of the screw 63 and maintained by the lock nut 64.

In this form of the device the unloading mechanism is all contained within the gear case itself and is not as susceptible to tampering as is the first described form of the device, although the two modifications described herein are identical in principle.

The operation of the deviceshown in Figs. 6 to 8 is identical with that shown in Figs. 1 to 5 inclusive, it being understood that the signaling and cut-out devices are applicable to either form. and that in either case when an overload has permitted the gears to move to a neutral position they must be returned to a driving position after the difliculty which occasioned the unloading has been removed before the coal-feeding operation can be resumed.

I am aware that many forms of unloading devices have been constructed in the past; it is therefore not my intention to cover such devices broadly, but I do intend to cover all such forms and modifications thereof as fall fairly within the appended claims.

I claim:

1. A mechanical unloader for underfeed stokers having in combination a rotatable selective gear set with a latch means for holding one set of gears in an operative position, and unloading means for releasing said gear set at the moment of overload and permitting same to pass'to a neutral position.

2. A mechanical unloader for underfeed stokers the combination of a rotatable gear case, and a spring-urged latch adapted to hold the cage in a driving position under a given load and to release same to a neutral position when said load is exceeded.

3. An unloading mechanism for selective rotatable gear sets consisting of a latch for holding said set in an operative position, manual. means for disengaging said latch, a frangible pinbetween said manual means and said latch, and an.

adjustable spring means for urging said latch toward a holding position.

HASKELL C. CARTER.

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