US2400207A - Demolition tool handle - Google Patents

Description

Filed J RRELLV ET AL 2,400,207

DEMOLITION TOOL HANDLE une 26, 1944 2 Sheets-Sheet l I May 14, 1946.

Filed June 26, 1944 2 Sheefs-Sheet 2 4554 45 Z 55 55 51 55 55 i5 54 T5 I 'v l a 1% ma 57 Ii 22 59 z {5 46 ii 17 lMvrrme'h' 07%??544 53/107950 J k'Lou/s Patented May 14, 1946 DEMOLITION TOOL HANDLE Matthew OFarrell, Detroit, Mich., and Alfred J.

St. Louis, Windsor, Ont to Chicago Pneumatic Tool ario, Canada, aSsignors Compan w York, N. Y., a corporation of New Jersey Application June 26, 1944, Serial No- 542,054

6 Claims.

This invention relates to a combined grip member and throttle lever or shifter for supporting and guiding a paving breaker or demolition tool of the type provided With a T-handle allowing the operator to press forward against two diametrically opposed grip portions while controlling the operation of the tool.

The main object of the invention is to provide a paving breaker or demolition tool of the T- handle type with a combination grip member and throttle lever or shifter which forms part of the T-handle and facilitates starting and stopping of the tool without materially modify ing or impairing the handling thereof by the operator.

Another object is to have a grip member forming part of a T-handle for a tool of the general character indicated which eliminates the necessity for a separate manual control means for the throttle valve requiring individual attention or manipulation.

A further object is to have such a grip member which is capable of being made in two forms following the same principle, the one form including a grip for only one hand forming but part of a T-handle and the other form including a more extensive grip forming the two grips of the T-handle for both hands of the operator.

Other objects and the advantages of the invention will appear in further detail as the specification proceeds, due reference being had to the accompanying drawings, in which:

Fig. l is a longitudinal section of the major portion of a pressure fluid operated paving breaker or demolition tool equipped with a combined grip and throttle lever or shifter;

Fig. 2 is a top plan view of the tool of Fig. 1 particularly illustrating the grip and throttle lever or shifter surmounting the tool;

Fig. 3 is an elevational view showing the grip and throttle lever or shifter as seen from the right end in Fig. 1;

Fig. 4 is a fragmentary section taken on line 4-4 in Fig. 2; and

Fig. 5 is a fragmentary view disclosing a modification of the grip and throttle lever or shifter in partial longitudinal section.

The invention illustrated preferably refers to a pneumatic tool although it may conceivably also be adapted to hydraulic tools when desired, as this invention refers more particularly to the control of the tool and not to the nature of the fluid operating the latter.

It is well known that on paving breakers anddemolition tools the conventional holding handle or grip membe consists of a rigid T-shaped member usually made integral with the backhead of the tool and having a throttle lever pivbtally connected with the handle proper and operating either above or below the gripp port o s o t handle neniber. Squeezing the lever against the handle proper causes the throttle to be opened w i h al ows ressur fluid o nt r a d ope at the tool. The main disadvantage inherent in such a son ntiona t pe of a dle or i is that when the ope at d sires to elea e the throttle lever in order to stop the inflow of pressure fluid to the tool, it has heretofore been neces ary r the o e ator to pa t r ease hi grip on the handle to allow the throttle valve to be c ed by a sp i g p id o i pu o e- By thus releasing his grip on the handle, his control of the tool is greatly impaired. In view of this, what frequently transpires is that in order to avoid imposing any limitations on or reducing his control of the tool the operator simply keeps .on squeezing the throttle lever, with the result that the hammer piston Within the tool con nue ing implement is in the run-out position. Frejquent repetition of this procedure tends to result in fracture of the front end parts of the tool and also causes considerable discomfort to the operator.

With the foregoing objects in View and in order to avoid the above indicated disadvantages, the

in ention s d si ned to n du w is i tually a new type of manual control for this class of tools as will now be set forth in detail.

In the'practice of the invention, a paving breaker or demoiition tool, generally indicated at HI in Fig. 1 has a cylinder casing H containing a reciprocable hammer piston I2 propelled by operating fluid entering piston chamber l3 through inlet passage H, and distributed to the respective ends of 'the piston chamber in the usualcycle of operation of hammer drills of the valveless type. The inlet passage i4 is controlled bythrottle valve 15 normally closed against valve seat It by valve spring I l in valve chamber I B which latter is connected through passage I9 with air, hoseli communicating with an outside source .of pressure fluid (not shown). The throttie valve an upwardly extending stem 22 slida'hly mounted in :backhead 23 which is secured to cylinder casing H by bolts 24 :(Fig. 2) in more m0 .1 5 conventional manner, the stem extending u throu h Said backhead with its upper end exposedin the deep channel or recess 25 thereof. During operation, the hammer piston delivers to reciprocate although the work its blows to an anvil block or tappet 2B in tappet bushing 21 and the tappet transmits the impacts received to working implement 28 in guide 29, the latter and the tappet bushing as well as casing l i being secured together by bolts (not shown) in conventional manner, and the working implement being a drill steel, chisel or other fo-rrn of tool according to the choice of theoperator.

Inasmuch as the features and operation of the tool are well known and thus not novel to the, invention, further description thereof is superfluous. Upon one side of the rear of the backhead 23, is an integral orrigid grip handle 3| preferably of hollow construction to lighten the same, the handle projecting radially with respect to the longitudinal central axis of the tool as a whole, A second grip handle 32 directed in the opposite direction to and normally inline with handle 3| is also of light hollow construction, extends into the recess 25 and is pivoted in position by a pivot pin 33 penetrating the side walls 34 of the recess, the handle 3| thus being more than a. mere grip handle as it also forms a pivoted lever. In order to render the handles 3| and 32 more comfortable to the hands of the operator, they are each provided with a rubber sleeve 35, handle 3| having a retaining flange 36 at its outer end, and handle 32 a similar retaining flange 31 at the opposite end of smaller diameter than that of flange 36, so that the operator can identify the latter and hold the tool as a whole in predetermined position.

The lever 32 has a headed contact member 38 fitted loosely in the latter and provided with a lower head 39 resting on the upper end of the throttle valve stem 22 in effective position to enable the handle 32, when depressed, to open velve l against valve spring and thereby cause pressure fluid from passage l9 and valve chamber l8 to enter piston chamber |3 through passage M. The bottom 4| of the recess forms a stop for the lower end 39 of contact member 38 as it is larger than the diameter of valve stem 22, and

' thus a lower limit is provided preventing excessive movement of lever 32 in the downward direction. The latter is not a mere throttle lever as it becomes a rigid part of the backhead following a slight forward movement. As contact member 38 is longer than the distance through the lever and mounted loosely in the latter, it may be operated independently of said handle, and touches the top of valve stem or shank 22 in all positions of the handle. Thus, if the working implement becomes so firmly stuck that in order to withdraw the same it is helpful to have the apparatus in operation, the operator may exert a continuous upward pull on both grips or handles, and by using his thumb, can hold the throttle valve IS in the open position by depressing the contact member 38 as long as required.

In raised initial or normal position of handle or lever 32, the contact member 38 projects a small distance above the pivoted portion 43 of the lever, and in order to avoid accidental contact of member 38 with various objects with resulting accidental operation of the tool, the side walls 34 have raised integral shield portions 45 serving as rigid guards projecting slightly above said member 38 upon both sides thereof and thereby protecting the same.

The valve spring I1 is selected to be sufficiently strong to move not only throttle valve l5 to closed position, but also to raise lever 32 to normal initial position, ready for operation. However,

- underbed, it frequently the curved far end 42 upon pivoted end portion 43 of the throttle lever 32 engages against the corresponding curved portion 44 of recess 25, and this engagement provides a limit to the upward or counterclockwise movement of the handle or throttle lever which comes to a stop in the position shown in Fig. 1 under influence of the valve spring when the latter closes the valve.

The particular utility of the combined grip and throttle lever just described is readily manifest when considering more carefully the type of work performed by the tool, such as breaking up concrete pavements etc. Such pavements are usually laid on an underbed of crushed rock or cinders, and because of the comparative softness of this occurs that the working implement of a conventional tool, after having penetrated the concrete, has a natural tendency to dig itself abruptly and deeply into the underbed. The reasons for this more or less uncontrolled behaviour of the tool is that the operator experiences difliculty in promptly releasing the conventional throttle lever because of the necessity of maintaining a suflicient grip on the handle to withdraw the tool from the work.

When instead the working implement of the tool above disclosed penetrates the concrete, the operator finds it perfectly natural to restrain the tool in its forward thrust and simultaneously to stop operation thereof by pulling up on both grips or handles, one of the latter releasing the valve stem and allowing the throttle valve to close.

A modification of the described form of the invention is illustrated in Fig. 5, the backhead 46 being shown in section and the lower portion of the tool omitted altogether, but throttle valve l5, valve spring IT and valve stem 22 are the same as before which is also true of contact member 38 with its lower contact head 39. In this form of the invention, the backhead has a pair of upright rear walls 41 (one shown) spaced apart in mutual parallelism to form an open slot or recess 48 with both ends open and the bottom 49 extending fully from one end to the other of said recess. The latter is adapted to receive the intermediate section of an elongated grip member 5| slidably mounted for vertical movement therein and retained in association with the backhead and particularly between the recess walls 41 by a pair of transverse pins 52 fast in said walls and passing through vertical elongated apertures or slots 53 in said grip member. The pins provide a positive stop limiting relative movement between the grip member and the backhead. The grip member has a pair of integral grip handles or hand grips 54, 55 projecting rigidly therefrom in opposite directions so as to overhang the sides of said backhead, both handles being equipped with the conventional sleeves 35 as in the case of grip handles 3| and 32.

The contact member 38 is loosely mounted in grip member 5| directly above valve stem 22 while recess walls 41 are provided with integral guards 56 (one shown) to protect said member asin the case of guards 45. In the form under consideration, grip member 5| is not a lever but a depressor for the valve stem. As this valve stem is located considerably off center in the backhead, a counterbalancing plunger 51 is slidably mounted in a plunger chamber ,58 located on the opposite side of the central axis of the tool and a spring 59 disposed in said chamber beneath the plunger to 'urge the latter resiliently upward against hand grip'member 5|. The immediate result of having "2,400,207 spring biased plunger 51 hearing against the hand and plunger to be depressed and the entire hand grip member lowered in thus caused to valve l5.

When the operator penetration of the working implement into the slot 48, a the tool being perate by the opening ofthrottle hand grips will allow valve spring I! and plunger spring 59 to close the valve and raise plunger 57 which simultaneously raises the member i, the latter being obviously limited in vertical movevalve and thereafter to allow the same to be returned in the upward direction by the springs with consequent closure of the valve, the movement of said member being in any case parallel and balanced.

In both forms of the invention, it is quite evident that the operator retains a good grip on both handles throughout the operation of the tool and causes operation or cessation thereof by the natural normally disposed in initial position and adapted upon displacement from said position to open the handle unit.

2. In a fluid actuated tool having means for supporting and guiding a working implement, a

and substantially aligned grip handles forming a rigid unit movably 'position with respect to 3 normally disposed in initial position and adapted upon displacement from said position to open the throttle valvameans upon the backhead which allows the handle unit to be displaced from initial the cylinder and'serves to stop the movement of said handle unit after a limited stroke and thereby causessaid cylinder to move positively forward with the handle unit, the throttle valve being engaged by an offcenter portion of the handle unit, a spring biased plunger mounted in the backhead in a position to engage against the handle unit at a counter- -3. In a fluid actuated tool having means for supporting and guiding a working implement, a cylinder with a piston chamber containing a reciprocable piston adapted to impart working impacts to the working implement, a backhead associated with said cylinder and a throttle valve for controlling the flow of pressure fluid to said cylinder for driving said piston, there being resilient means tending to close said throttle valve, the combination of a pair of mutually opposite and substantially aligned grip handles forming a rigid unit movably mounted on the backhead in an initial position to engage the throttle valve, and a pair of rearwardly directed rigid members spaced apart upon the backhead to form guide means for said movably mounted unit allowing displacement thereof from initial position in order to open said throttle valve.

4. In a fluid actuated tool having means for supporting and guiding a working implement, a cylinder with a piston chamber containing a reciprocable piston adapted to impart working impacts to the working implement, a backhead associated with said cylinder and a throttle valve for controlling the flow of pressure fluid to said cylinder for driving said piston, there being resilient means tending to close said throttle valve, the combination with a grip handle rigidly disposed on the backhead substantially at right angles to the longitudinal axis of the tool as a Whole, of a pair of cess between said rigid members and the other end in initial position projecting from the recess upon depression of the same grip handle, and means upon said inner end of said second grip handle for engaging against an inner portion of said recess to provide a stop for said grip handle for determining the initial position thereof.

5. A fluid actuated tool according to claim 4, in which the portion upon the second grip handle adapted to open the valve comprises a contact member mounted in association with said second grip handle and having one portion adapted for depressing the throttle valve and another portion projecting rearwardly upon said grip handle, and

projecting rigid contact member from accidental contact with outside objects.

6. In a fluid actuated tool having means for supporting and guiding a working implement, a cylinder with a piston chamber containing a reciprocable piston adapted to impart working impacts to the working implement, a, backhead associated with said cylinder and a throttle valve for controlling the flow of pressure fluid to said cylinder for driving said piston, there being resilient means tending to close said throttle valve, a grip handle supported on said backhead, means on the backhead which allows said grip handle to be displaced forwardly from initial position with respect to the cylinder and serves to stop the movement of said portion after a limited stroke and thereby causes said cylinder to move positively forward with said grip handle, said handle having an aperture which is in alinement with said throttle valve and extends transversely through the handle, a contact member slidably mounted in said aperture and having a head at each end, said heads being spaced sufficiently to permit limited relative movement between the contact member and the hammer, one of said heads normally resting on the throttle valve and arranged to open the same when the grip handle is displaced forwardly from initial position, the other head on the contact member being normally held in spaced relation to the handle by the spring and adapted to be moved forwardly independently of the handle to open the throttle valve when the grip handle is in its initial position.

MATTHEW OFARRELL. ALFRED J. ST. LOUIS.

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