JPS599774Y2 - hammer drill mechanism - Google Patents

Description

[Detailed description of the invention] The purpose of the invention is to use a hammer, drill, etc., which has a spindle that is rotated by a motor via a gear and has a tool pit attached to its tip, and a notch at the rear end of the spindle. A movable toothed hammer member is fixed concentrically about the spindle, and rotation of the spindle with such notched teeth engaged with notched teeth of a fixed hammer member fixed within the gear case cover causes the aforementioned The cam-like action between the two notched teeth allows the movable hammer member and the spindle to which it is fixed to repeatedly reciprocate in the axial direction to perform the hammer drilling operation, and is normally attached to the power tool body. The spindle is pulled toward the front of the tool by the provided tension spring, so that the two notched teeth are not engaged, so that only a rotational movement, that is, a drilling movement, can be performed.
For portable power tools such as drills, movable hammer members and gear case covers are used to prevent hammer drilling from occurring even when the tool bit is pressed against the workpiece when the operator only wishes to perform such drilling operations. a shift washer having a cam and rotatably and axially slidable between the movable hammer member and the spindle by the cam action between the cam and the cam on the gear case force bar. two modes of operation, drilling and hammer drilling, for moving away from the fixed hammer member, thereby making it impossible to engage the two notched teeth with each other and thus preventing a hammer drilling operation; The purpose of the present invention is to provide a switching device 5.

The portable power tool has two modes of operation, one for drilling and the other for hammer drilling.

This tool has a motor housing, a gear case mounted in front of the motor housing, and a gear case cover between the two, the latter forming the inner wall of the housing.

The rear portion of the axially movable spindle is journal-mounted in a bearing in the gear case force bar.

A fixed hammer member is fixed in the gear case cover in the radial direction of the spindle bearing.

The movable hammer member is carried by the spindle and includes notched teeth adapted for ratcheting engagement with corresponding notched teeth on the stationary hammer member during hammer drilling modes of operation.

A shift member is disposed radially of the fixed hammer member, and thrust bearing means is provided between the shift member and the movable hammer member.

Means having a shift button is provided for rotating the shift member through an angle about the axis of the spindle.

Cooperative cam means are formed between the shift member and the gear case force bar such that rotation of the shift member causes axial movement thereof, thereby moving the movable hammer member into engagement with the fixed hammer member during the drilling mode of operation. It is designed to solve the problem.

Referring to FIG. 1, a portable power tool 10, referred to in the art as a hammer drill, is shown.

The tool 10 has a motor housing 11, a gear case 12, and a gear case cover 13 therebetween, the latter defining an inner wall within the tool housing.

Additionally, the hammer drill has a handle 14, a switch 15 for energizing the motor within the motor housing, and a chuck 16 for receiving a suitable tool bit or other implement.
has.

For convenience of illustration, the motor and tool bit are not shown.

The motor has an armature shaft 1 journal mounted in a first sleeve bearing 18 in a gear case force bar.
It has 7.

A pinion 19 is formed on the armature shaft and engages an intermediate gear 20 mounted on an intermediate shaft 21 journaled within the gear case.

Intermediate gears 22 and 23 (different in size) are carried by an intermediate shaft and a corresponding gear 24, which is loosely carried by a spindle 26 on which a chuck is mounted.
25.

The gears 24, 25 are normally rotatably and axially slidable relative to the spindle 26.

Each gear 24, 25 has its own compression spring 27. Biased in opposite directions by 28, each gear has a notched portion 29, 30 adapted for clutch engagement with a pin 31 fixed in a suitable manner to the spindle.

Manually operable adjustment means (not shown) are provided (not shown) for sliding one of the gears (24 or 25) axially away from the pin, thereby bringing the other gear into engagement with the pin, thereby causing the other gear to slide axially away from the pin. Key the gear to the spindle.

That is, the compression spring 28 compresses the gear 25 in FIGS. 1 and 2.
When the gear is suspended to the right in the figure, a pin 31 fixed to the spindle 26 engages with a notch 30 of the gear 25.

When the gear adjusting means is operated, for example, the gear 25 is moved to the left in FIGS. 1 and 2, the notch 30 is disengaged from the pin 31, the compression spring 27 moves the gear 24 to the left,
Notch 29 of gear 24 engages pin 31.

The pin 31 is non-rotatably fixed to the spindle 26 and thus rotates together with the spindle.

As a result, when the notches 29, 30 of the gear 24 or 25 are engaged with the pin 31, the gear 24 or 25
rotates together with the spindle 26.

This is a known mechanism commonly referred to as a "dog clutch."

The gear adjusting means is a mechanism for moving the gear in the axial direction of the spindle, and any suitable known mechanism can be used.

This two-speed gear shifting mechanism is disclosed in U.S. Pat. No. 3,178,955 and U.S. Pat.
No. 78956, both patents are assigned to the assignee of the present invention.

Referring again to FIG. 1, and with further reference to FIGS. 2-4, the spindle is axially movable and is normally moved forward, i.e., by the countersunk spring 26A, which is a tension spring. It is biased to the left in Figure 1 and Figure 2.

Additionally, it has a spindle aft portion 26B which is journal mounted within a second sleeve bearing 32 mounted within the gear case force bar.

A fixed hammer member consisting of a flanged bushing 33 is fixed concentrically around the bearing 32 and fixed within the gear case cover.

A movable hammer member 34 is fixed concentrically in a suitable manner on the spindle in front of the fixed hammer member.

As seen in FIGS. 2, 3 and 4, these hammer members have corresponding notched teeth 35, 36, respectively, which ratchet into each other in the hammer drilling mode of operation so that the spindle is When rotated, the camming action between the engaged notched teeth 35, 36 causes the spindle to move axially in a repetitive manner to effect a hammer drilling action.

The notched teeth 35 of the fixed hammer member 33 and the notched teeth 36 of the movable hammer member 34 are known, have similar shapes, have protuberances (teeth) and stubs (notches); When the spindle 26 and the movable hammer member 34 fixed to the spindle 26 rotate while the protruding part of the ridge is engaged with the other stub, one ridge rides on the other ridge and then engages the stub again. The rapid repetition of this action causes repetitive axial reciprocating motion of the movable hammer member and the spindle to which it is fixed.

Such notched teeth and their operation are known.

When using a tool, when an operator presses the tool carried by the chuck against a workpiece, the spindle is biased axially rearward, ie, to the right in FIGS. 1 and 2.

This bias pressure causes the spindle to retreat axially into the gear case against the force of countersunk spring 26A, ratcheting the notched teeth on each hammer member, thereby providing a hammer drilling mode of operation.

In this case, by the manual adjustment described above, when the gear 24 on the spindle 26 is brought into clutch engagement with the pin 30, a low speed hammer drilling mode of operation is obtained, and the gear 25 is brought into clutch engagement with the pin 30.
0 and clutch engagement provides a high speed hammer drilling mode of operation.

The shift I member consisting of the washer 37 is the fixed hammer member 3
3 and has a radially projecting tongue 38 which engages a transverse slot 39 formed in the shift button 40.

The shift button may be of suitable shaped plastic and is guided for limited alternating rotational movement within an arcuate slot 41 (FIG. 4) formed in the gear case cover between the motor housing and gear case. be done.

The connection between the tongue 38 and the slot 39 allows the shift button 40 and shift washer 37 to rotate together through an angle about the axis of the spindle.

A cam surface 42 is formed on the side of the shift washer facing the gear case force bar and engages a corresponding cam 43 (FIG. 3) on the gear case cover.

These cams 42 and 43 have corresponding shapes and each consist of four axially raised peaks and four valleys therebetween.

When the peaks and valleys of each cam are engaged, the shift washer 37 is axially located furthest to the right, so that the notched teeth of the movable hammer member are aligned with the notched teeth of the fixed hammer member. Does not prevent engagement.

By rotating the shift washer, the cam 42. When the respective peaks of 43 are engaged with each other, the shift washer moves to the left, pushing the movable hammer member that is in contact with it via the thrust bearing 44 and moving it to the left, so that the spindle 26 also moves to the left. As the shift washer becomes impossible to move to the right due to the engagement between the ridges, it becomes impossible for the toothed teeth 35 and 36 to engage with each other, and even when the tool bit is pressed against the workpiece, the hammer does not・Drilling motion cannot occur.

This is the tool's drilling mode of operation.

The thrust bearing 44, as shown in FIG. and can slide in contact with the movable hammer member 34.

In this case, by the manual adjustment described above, clutching the gear 24 on the spindle 26 with the pin 30 provides a low-speed drilling mode of operation, and clutching the gear 25 with the pin 30 provides a high-speed drilling mode of operation. .

As shown in FIGS. 3 and 4, the shift button 40 has arcuately spaced pockets 45A, 45B that are connected to respective projecting lugs integrally cast within the gear case force bar. 46A and 46B are accepted alternately.

The shift button 40 has some elasticity due to its arcuate shape and material, so if you rotate the shift button with force, the shift button will elastically deform slightly when it comes into contact with the lug, causing the lug to move in and out of the pocket. be done.

The cooperation between them limits the arcuate movement of the shift button and
Detent-type “snap action”
ion”) to disable inadvertent movement of the shift button.

As will be understood by those skilled in the art, this invention provides a low cost, relatively high capacity power tool that can be adjusted for drilling or "hammer drilling" at will by the operator. It provides a simple and reliable mechanism.

Additionally, the two-speed transmission provides "low speed" and "high speed" operation, thereby providing a total of four distinct modes of operation.

[Brief explanation of the drawing]

FIG. 1 is a side view of the tool, partially cut away and in section to show the mechanism adjusted to the hammer drill mode of operation. 2 is a side view of a portion of FIG. 1 showing the mechanism adjusted to a drilling mode of operation; FIG. FIG. 3 is an exploded perspective view of the mechanism shown in FIGS. 1 and 2. FIG. FIG. 4 is a sectional view taken along line 44 in FIG. 2. 10: Portable electric tool, 11: Motor housing,
12: Ga case, 13: Ga case cover, 17: Armature shaft, 18: First sleeve bearing, 2
6: Spindle, 32: Second sleeve bearing, 33
: Fixed hammer member, 34: Movable hammer member, 35, 36
: notched tooth, 37: shift member, 40: shift button, 41: arcuate slot, 42. 43: Cam surface, 4
4: Thrust bearing.

Claims (1)

[Scope of claim for utility model registration] A motor housing, a gear case provided in front of the motor housing, a gear case cover between the gear case and the motor housing, a tool can be attached to the tip, a journal is attached to the gear case, and it is attached in the axial direction by a spring. a spindle driven by a motor, movable axially and retractably; a fixed hammer member disposed from a bushing concentrically disposed around the spindle bearing of the gear case force bar; carried on the spindle in front of the fixed hammer member; A portable power tool having a movable hammer member, notched teeth formed on each of the fixed hammer member and the movable hammer member that engage each other in a hammer drilling mode of operation to produce hammering movement of the spindle, a shift washer having a cam surface on the gear case cover, a cam surface disposed concentrically around a fixed hammer member between the gear case cover and the movable hammer member, and capable of being engaged cooperatively with the cam surface; a shift washer and movable; and means for rotating the shift washer by a certain angle about the axis of the spindle, so that when the shift washer is rotated, the shift washer moves in the axial direction and the movable hammer member is moved away from the fixed hammer member a sufficient distance to disable the engagement of the notched teeth formed on the movable and fixed hammer members, and thus to cause the notched teeth to interact with each other in the drilling mode of operation. It is characterized in that the hammering operation of the spindle due to action is made impossible. An operating mode switching device for a portable power tool having two selective operating modes: drilling and hammer drilling.